text1
stringlengths 13
1.97M
|
|---|
Test apparatus and measurement apparatus for measuring an electric current consumed by a device under test
There is provided a test apparatus for testing a device under test, which includes a voltage supplying section that supplies a voltage to the device under test through a wire, a first capacitor that is arranged between the wire and a common potential in series, a current detecting section that detects a current flowing through the wire at a location closer to the device under test than the first capacitor is, an integrating section that outputs an integration value obtained by integrating a difference between the current detected by the current detecting section and a predetermined reference current, and a judging section that judges whether the device under test is a pass or a failure based on the integration value.
BACKGROUND
1. Technical Field
The present invention relates to a test apparatus and a measurement apparatus. Particularly, the present invention relates to a test apparatus and a measurement apparatus for measuring an electric current consumed by a device under test (load).
2. Related Art
A test apparatus has a function of measuring an average current to be consumed by a device under test when the device operates. The test apparatus detects a current output from a power source device that supplies a drive voltage to the device under test, and measures the average current consumed by the device under test.
Here, the power source device is slow in responding to any change in the current consumed by the load. Accordingly, the test apparatus has a bypass capacitor having relatively large capacitance, between its power source line and the ground, in order to compensate for any response delay of the current output from the power source device. With this, the test apparatus can supply a drive current to the device under test even in a case where it makes the device under test operate in such a manner as would require the current consumed by the device under test to change quickly.
Here, in a case where the test apparatus has a bypass capacitor, the current to be consumed by the device under test and the current output from the power source device do not coincide. Hence, the test apparatus cannot correctly measure the average current consumed by the device under test, by detecting the output current from the power source device.
Thus, a conceivable test apparatus to overcome this problem is such one that has, near the device under test, an AD converter which samples the drive current to be supplied to the device under test. However, since the drive current supplied to the device under test changes quickly, the test apparatus has to make the AD converter perform sampling quickly. Accordingly, the test apparatus has to be provided with a high-performance AD converter. Further, since there will be a large amount of data that should be taken in, the test apparatus has to be provided with a data memory having a large capacity.
Furthermore, in testing multiple devices under test of about several hundreds or so simultaneously, the test apparatus has to have the same number of current measuring sections as the number of devices under test. Therefore, it is preferred that the test apparatus be structured as a simple circuit in order to be able to measure the average current consumed by the device under test.
When measuring the current of the device under test, a measurement error is caused by an offset in the operating amplifier used by the measuring circuit. To solve this problem, it is necessary to adjust the offset to be equal to zero. But if a plurality of measurement channels are provided, it is necessary to adjust the offset of each channel because each operating amplifier has a different offset. To achieve this, a way to adjust the error caused by the offset automatically and with the same process is sought.
During the initial evaluation of the device under test, the value of the value of the current may be sought in addition to the test result indicating pass/fail of the current test of the device under test. Therefore, a way to easily obtain the current value is desired.
SUMMARY
Therefore, it is an object of an aspect of the innovations herein to provide a test apparatus and a measurement apparatus, which are capable of overcoming the above drawbacks accompanying the related art. The above and other objects can be achieved by combinations described in the independent claims. The dependent claims define further advantageous and exemplary combinations of the innovations herein.
According to a first aspect related to the innovations herein, one exemplary test apparatus may include a test apparatus for testing a device under test, having: a voltage supplying section which supplies a voltage to a device under test through a wire; a first capacitor which is arranged between the wire and a common potential in series; a current detecting section which detects a current flowing through the wire at a location which is closer to the device under test than the first capacitor is; an integrating section which outputs an integration value obtained by integrating a difference between the current detected by the current detecting section and a predetermined reference current; and a judging section which judges whether the device under test is a pass or a failure based on the integration value.
According to a second aspect related to the innovations herein, one exemplary measurement apparatus may include a measurement apparatus for measuring a current flowing through a load, having: a first capacitor which is arranged between a wire for supplying a voltage to the load and a common potential in series; a current detecting section which detects a current flowing through the wire at a location closer to the load than the first capacitor is; and an integrating section which outputs an integration value obtained by integrating a difference between the current detected by the current detecting section and a predetermined reference current.
According to a third aspect related to the innovations herein, one exemplary test apparatus may include the test apparatus according to the first aspect, wherein the integrating section has: an integrating circuit which stores charges corresponding to a current indicating the difference between the current detected by the current detecting section and the reference current in a capacity element, and outputs an integration voltage that occurs across both ends of the capacity element as the integration value; and an offset correcting section that corrects an offset occurring at an input of the integrating circuit.
According to a fourth aspect related to the innovations herein, one exemplary test apparatus may include the test apparatus according to the first aspect, further including an AD converting section that measures the integration value, wherein the AD converting section has: a recording section that records digital values obtained by measuring the integration value for each measurement cycle; and a processing section that scales the digital values obtained respectively for each measurement cycle recorded on the recording medium with measured values obtained when only the reference current is input before or after a series of measurements.
The above summary of the invention is not intended to list all necessary features of the present invention, but sub-combinations of these features can also provide an invention.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
One aspect of the present invention will be described below through an embodiment of the invention, but the embodiment below is not intended to limit the invention set forth in the claims, or all the combinations explained in the embodiment are not necessarily essential to the means of solving provided by the invention.
FIG. 1shows the configuration of a test apparatus10according to the present embodiment, together with a device under test (DUT)200. The test apparatus10comprises a signal generating section17, a voltage supplying section18, a measurement apparatus20, a reference voltage generating section21, a signal acquiring section22, and a system control device23, and tests the DUT200.
The DUT200is tested by the test apparatus10, for example, while it is loaded on a performance board or the like. The signal generating section17supplies a test signal corresponding to a test pattern to the DUT200.
The voltage supplying section18supplies a voltage to the DUT200through a wire12. The voltage supplying section18may, for example, supply a voltage for driving the DUT200, to a power source terminal of the DUT200. The voltage supplying section18may, for example, detect a voltage (drive voltage Vdd) at a point (a detection end14) on the wire12that is near the DUT200and control its output voltage such that the detected drive voltage Vdd becomes a predetermined value.
The measurement apparatus20measures an average consumption current of the DUT200(for example, an average consumption current when the DUT200is in operation). Then, the measurement apparatus20judges whether the average consumption current of the DUT200is larger or not (or smaller or not) than a predetermined reference current IREF. Note that the measurement apparatus20may, for example, be located at a device interface section such as a socket or the like, into which the performance board and the DUT200are inserted.
The reference voltage generating section21generates a reference voltage VREFfor generating the reference current IREF, and supplies it to the measurement apparatus20. The reference voltage generating section21supplies the reference voltage VREFto the measurement apparatus20, for example, prior to a test, in accordance with the control of the system control device23.
The signal acquiring section22judges whether an output signal to be output from the DUT200in response to a test signal is a pass or a failure. In addition, the signal acquiring section22judges whether the DUT200is a pass or a failure based on a result of judgment by the measurement apparatus20.
The system control device23includes a memory which stores a program therein, a CPU which executes the program, etc. The system control device23exchanges data with the signal generating section17, the voltage supplying section18, the reference voltage generating section21, and the signal acquiring section22to control the testing operation of the test apparatus10.
FIG. 2shows the configuration of the measurement apparatus20according to the present embodiment, together with the voltage supplying section18and the DUT200. The measurement apparatus20comprises a first capacitor24, a second capacitor26, a current detecting section28, an integrating section30, a judging section32, a setting section34, and a control section36.
The first capacitor24is arranged between the wire12and a common potential in series. For example, the first capacitor24may be connected to the wire12at a location closer to the voltage supplying section18than the detection end14is. The common potential may, for example, be a ground potential, or any other reference potential. When the current to be consumed by the DUT200changes quickly and an output current IPfrom the voltage supplying section18lags behind in responding to that change, the first capacitor24can supply the DUT200with a current to be consumed that amounts to this change.
The second capacitor26is arranged between the wire12and the common potential in series at a location closer to the DUT200than the first capacitor24is. The second capacitor26may, for example, be connected to the wire12at a location farther from the DUT200than the detection end14is.
Further, the second capacitor26has smaller capacitance than the first capacitor24. The capacitance of the second capacitor26may be, for example, about 1/10 to 1/1000 of the capacitance of the first capacitor24. When a high-frequency noise such as a ripple or the like gets superimposed on the wire12, the second capacitor26can drop the noise to the common potential (for example, the ground potential). Accordingly, it is preferred that the second capacitor26be connected to the wire12at a location as close to the DUT200as possible.
The current detecting section28detects a current IRMflowing through the wire12, at a location that is closer to the DUT200than the first capacitor24is and farther from the DUT200than the second capacitor26is. That is, the current detecting section28detects the current IRMflowing through the wire12at a location between the first capacitor24and the second capacitor26.
Here, since the current detecting section28detects the current flowing through the wire12at the location closer to the DUT200than the first capacitor24is, it can detect a current, which is the sum of the current supplied from the voltage supplying section18to the DUT200and the current supplied from the first capacitor24to the DUT200. That is, the current detecting section28can detect a current that coincides with a drive current IDDto be supplied to the DUT200. Accordingly, even in a case where the output voltage IPfrom the voltage supplying section18gets behind in responding to any change in the current to be consumed by the DUT200and hence the current to be consumed by the DUT200and the output current IPfrom the voltage supplying section18lose coincidence, the current detecting section28can correctly detect the drive current IDDto be supplied to the DUT200.
Note that the second capacitor26likewise supplies a current to the DUT200when the current to be consumed by the DUT200changes quickly. However, since the capacitance of the first capacitor24is larger than that of the second capacitor26, the current to be supplied from the first capacitor24to the DUT200is larger than the current to be supplied from the second capacitor26to the DUT200(for example, about 10 times to 1000 times larger). Accordingly, the current IRMflowing through the wire12between the first capacitor24and the second capacitor26can be said to be approximately the same as the drive current IDDto be supplied to the DUT200. Thus, the current detecting section28can correctly detect the drive current IDDto be supplied to the DUT200.
The current detecting section28may include, for example, a detection resistor42and a potential difference detecting section44. The detection resistor42is arranged so as to intervene in the wire12at a location between the first capacitor24and the second capacitor26in series. The detection resistor42may be, for example, a minute resistor of about several milliohms. The potential difference detecting section44outputs a detection voltage VXwhich is proportional to the potential difference between both the ends of the detection resistor42. Such a current detecting section28can output the detection voltage VXwhich is proportional to the current IRMflowing through the wire12between the first capacitor24and the second capacitor26.
Instead of the above, the current detecting section28may include a coil arranged intervening in the wire12at a location between the first capacitor24and the second capacitor26in series, and a detecting section which detects the current flowing through that coil. Such a current detecting section28can also detect the current IRMflowing through the wire12between the first capacitor24and the second capacitor26.
The integrating section30outputs an integration value obtained by integrating the difference between the current IRMdetected by the current detecting section28and the predetermined reference current IREF. For example, the integrating section30may store the charges that correspond to the current indicating the difference between the current IRMdetected by the current detecting section28and the predetermined reference current IREF, in any capacity element. Then, for example, the integrating section30may output an integration voltage that occurs across both the ends of the capacity element in which the charges are stored, as the integration value. An example of a detailed configuration of the integrating section30will be explained with reference toFIG. 3.
Since this integrating section30integrates the difference between the current IRMdetected by the current detecting section28and the reference current IREF, it will output an integration value (integration voltage) which is larger than 0 in a case where the average current of the current IRMis equal to or smaller than the reference current IREF, and which is equal to or smaller than 0 in a case where the average current of the current IRMis larger than the reference current IREF. Here, the current IRMdetected by the current detecting section28coincides with the drive current Idd to be supplied to the DUT200. That is, the average current of the current IRMcoincides with the average consumption current of the DUT200. As known from this, the integrating section30can output an integration value (integration voltage) which is larger than 0 when the average consumption current of the DUT200is equal to or smaller than the reference current IREFand which is equal to or smaller than 0 when the average consumption current of the DUT200is larger than the reference current IREF.
The judging section32judges whether the DUT200is a pass or a failure based on the integration value output from the integrating section30. The judging section32may judge whether the average consumption current of the DUT200is larger or not (or smaller or not) than the predetermined reference current IREF, by, for example, comparing whether the integration value output from the integrating section30is larger or not (or smaller or not) than a predetermined threshold (for example, 0). The judging section32may, for example, output a judgment which indicates a pass (the average consumption current is equal to or smaller than the predetermined reference current IREF) in a case where the integration value is positive, and which indicates a failure (the average consumption current is larger than the predetermined reference current IREF) in a case where the integration value is negative.
The setting section34sets the integrating section30to be at the reference current IREF, prior to a test. The setting section34may, for example, set the reference current IREFaccording to the type, grade, or the like of the DUT200, or the content of the test on the DUT200or the like. This allows the measurement apparatus20to judge, for example, whether the average consumption current of the DUT200exceeds an upper limit (or falls below a lower limit) designated as the specifications of the DUT200.
The control section36controls the integration period of the integrating section30. For example, the control section36controls the integrating section30to start integrating at a test start timing and controls the integrating section30to terminate integrating at a test end timing.
Further, in a case where the integrating section30stores the charges corresponding to the current indicating the difference between the current IRMdetected by the current detecting section28and the reference current IREFin the capacity element, the control section36may, prior to a test, discharge the charges stored in the current detecting section28in its capacity element to zero the charges from the capacity element. By doing so, the control section36can make a correct integration voltage be output from the integrating section30.
Since the measurement apparatus20as described above stores the integration value, it has only one sampling value that should be retained and does not therefore have to have a data memory or the like. Further, this measurement apparatus20can correctly compare the average consumption current of the DUT200and the reference current IREFeven when the current to be consumed by the DUT200fluctuates quickly. Furthermore, since the measurement apparatus20can be a simply-structured circuit to be able to measure the average consumption current of the DUT200, a small apparatus scale will suffice even in a case where, for example, several-hundred DUTs200are to be tested at a time.
FIG. 3shows one example of the configuration of the integrating section30and the judging section32according to the present embodiment. For example, the integrating section30may include an integrating circuit50, a reference current source52, a current letting-flow section54, and a discharging section56. Further, the judging section32may include a comparator58, for example.
The integrating circuit50stores the charges corresponding to the current indicating the difference between the current IRMdetected by the current detecting section28and the reference current IREFin the capacity element, and outputs an integration voltage VMthat occurs across both the ends of the capacity element as an integration value. For example, the integrating circuit50may include an operating amplifier60and an integrating capacitor62. The operating amplifier60has its non-inverting input terminal connected to the common potential. The integrating capacitor62is connected between the output terminal and inverting input terminal of the operating amplifier60.
The integrating circuit50having this configuration stores charges corresponding to an input current input to the inverting input terminal of the operating amplifier60in the integrating capacitor62. Then, the integrating circuit50can output the integration voltage VMthat occurs across both the ends of the integrating capacitor62in which the charges are stored. Note that the integrating circuit50outputs the integration voltage VM, which has been inverted in positive/negative characteristic from the result of integrating the input current.
The reference current source52gets the reference current IREFto flow out from the inverting input terminal of the operating amplifier60. The current letting-flow section54makes the current IRMdetected by the current detecting section28flow into the inverting input terminal of the operating amplifier60. Accordingly, the reference current source52and the current letting-flow section54can supply the current indicating the difference obtained by subtracting the reference current IREFfrom the current IRMdetected by the current detecting section28to the inverting input terminal of the operating amplifier60as an input current thereto.
The reference current source52may, for example, include a first voltage follower circuit64and a first reference resistor66. The first voltage follower circuit64has its input terminal supplied with a reference voltage −VREFfrom the setting section34and outputs a voltage equal to the reference voltage −VREFfrom its output terminal. The first reference resistor66is connected between the output terminal of the first voltage follower circuit64and the inverting input terminal of the operating amplifier60, and has a predetermined resistance value RREF1. The reference current source52having this configuration can make the reference current IREF(=VREF/RREF1), which is obtained by dividing the reference voltage VREFby the resistance value RREF1, flow out from the inverting input terminal of the operating amplifier60.
The current letting-flow section54may, for example, include a second voltage follower circuit68and a second reference resistor70. The second voltage follower circuit68has its input terminal supplied with the detection voltage VXfrom the current detecting section28and outputs a voltage equal to the detection voltage VXfrom its output terminal. The second reference resistor70is connected between the output terminal of the second voltage follower circuit68and the inverting input terminal of the operating amplifier60, and has a predetermined resistance value RREF2. The current letting-flow section54having this configuration can make the current IRM(=VX/RREF2), which is obtained by dividing the detection voltage VXby the resistance value RREF2, flow into the inverting input terminal of the operating amplifier60. The resistance value RREF2may, for example, be determined beforehand based on the relationship between the detection voltage VXfrom the current detecting section28and the current IRMflowing through the wire12.
The discharging section56discharges the charges stored in the integrating capacitor62of the integrating circuit50prior to a test. For example, the discharging section56may include a discharging switch72, a first switch74, and a second switch76. The discharging switch72causes a short circuit across both the ends of the integrating capacitor62in discharging the integrating capacitor62. Further, the discharging switch72opens both the ends of the integrating capacitor62during a test.
The first switch74connects the input terminal of the first voltage follower circuit64to the common potential in the discharging operation. The first switch74connects the input terminal of the first voltage follower circuit64to the reference voltage −VREFduring a test. The second switch76connects the input terminal of the second voltage follower circuit68to the common potential in the discharging operation. The second switch76connects the input terminal of the second voltage follower circuit68to the detection voltage VXduring a test.
The discharging section56having this configuration can discharge the charges stored in the integrating circuit50in the discharging operation. Also, the discharging section56can store the charges corresponding to the current indicating the difference between the current IRMdetected by the current detecting section28and the reference current IREFin the integrating circuit50during a test.
The comparator58compares the integration voltage VMoutput from the integrating circuit50with the common potential (for example, the ground potential), and outputs a judgment corresponding to the result of comparison. That is, the comparator58can detect whether the integration voltage VMoutput from the integrating circuit50is positive or negative, and output a judgment corresponding to whether it is positive or negative.
For example, in a case where the integration voltage VMis positive (for example, equal to or larger than 0), the comparator58may judge that the average consumption current of the DUT200is equal to or smaller than the predetermined reference current IREFand hence output a pass judgment. Further, for example, in a case where the integration voltage VMis negative (for example, smaller than 0), the comparator58may judge that the average consumption current of the DUT200is larger than the predetermined reference current IREFand output a failure judgment. As such, since the comparator58needs only to detect the positive or negative characteristic of the integration voltage VMoutput from the integrating circuit50, judging whether a pass or a failure is available with a simple configuration.
FIG. 4shows one example of the drive current Idd to be supplied to the DUT200during a test (which is equal to the current to be consumed by the DUT200). For example, the test apparatus10may control the DUT200to operate during a test such that a drive current Idd as shown inFIG. 4flows through the DUT200.
That is, the test apparatus10may control the DUT200to operate during a test such that the drive current Idd switches between 0.50 A and 1.00 A within a 4 μs period (with a duty ratio of 50%) as shown inFIG. 4. As a result, the average consumption current of the DUT200after the time (0 μs) is 0.75 A. In the example ofFIG. 4, prior to the time (0 μs), the test apparatus10controls the DUT200to operate such that the average consumption current is 0.50 A.
FIG. 5shows a result of simulating the output current IPoutput from the voltage supplying section18in a case where the DUT200is controlled to operate as shown inFIG. 4.FIG. 5shows a simulation result under a regulated condition that the first capacitor24is 330 μF, the second capacitor26is 1 μF, a wire resistance from the voltage supplying section18to the detection end14is 5 mΩ, a wire resistance from the detection end14to the DUT200is 5 mΩ, and the voltage value of the detection end14is 1.20V.FIG. 6toFIG. 9show simulation results obtained under the same condition.
As shown inFIG. 5, the voltage supplying section18outputs an output current IPwhich does not timely respond to the average consumption current of the DUT200. Specifically, the voltage supplying section18outputs an output current IPwhich will reach the average consumption current (0.75 A) of the DUT200at a time 200 μs.
FIG. 6shows a result of simulating the drive voltage Vdd in a case where the DUT200is controlled to operate as shown inFIG. 4. The voltage supplying section18reduces its output voltage during a period in which it increases its output current IP. Then, the voltage supplying section18returns the output voltage to its original after the output voltage IPgets stabilized. Accordingly, the drive voltage Vdd gradually decreases until before the output current IPbecomes stabilized (time 0 μs to time 200 μs) and gradually increases after the output current IPbecomes stabilized (after time 200 μs), as shown inFIG. 6.
FIG. 7shows a result of simulating a current ICL1which flows through the first capacitor24in a case where the DUT200is controlled to operate as shown inFIG. 4. The current ICL1which flows through the first capacitor24changes its amplitude in synchronization with the fluctuations of the drive current Idd.
In a case where the output current IPlags behind in responding to a change in the average consumption current of the DUT200, the first capacitor24supplies a current to fill the shortage, which is the difference obtained by subtracting the output current IPfrom the average consumption current, to the DUT200. Accordingly, during the period in which the voltage supplying section18increases the output current IP(before time 200 μs), the average value of the current ICL1takes a negative value. After the time at which the output current IPbecomes stabilized (after time 200 μs), the average value of the current ICL1increases from a negative value toward 0.
FIG. 8shows a result of simulating a current ICL2which flows through the second capacitor26in a case where the DUT200is controlled to operate as shown inFIG. 4. The current ICL2which flows through the first capacitor24changes its amplitude in synchronization with the fluctuations of the drive current Idd. However, since the second capacitor26has much smaller capacitance than that of the first capacitor24, it cannot supply a current enough to fill the shortage, which is the difference obtained by subtracting the output current IPfrom the average consumption current, to the DUT200. Hence, the average value of the current ICL2takes 0 even when any change occurs in the average consumption current of the DUT200.
FIG. 9shows a result of simulating the current IRMwhich flows through the wire12between the first capacitor24and the second capacitor26in a case where the DUT200is controlled to operate as shown inFIG. 4. As shown inFIG. 9, the average value of the current IRMis 0.75 A all the time. That is, even during the period in which the voltage supplying section18increases the output current IP(before time 200 μs), the average value of the current IRMcoincides with the average consumption current of the DUT200.
The test apparatus10judges whether the average consumption current of the DUT200is larger than the predetermined reference current IREFor not, based on the integration value obtained by integrating the difference between the current IRMflowing through the wire12between the first capacitor24and the second capacitor26and the reference current IREF. Accordingly, the test apparatus10can accurately judge whether the average consumption current of the DUT200is larger than the reference current IREFor not at all the times.
FIG. 10shows the configuration of the test apparatus10according to a first modification of the present embodiment, together with the DUT200.FIG. 11shows one example of a reference current IREFwhich is set by a search section82of the test apparatus10according to the first modification. The test apparatus10according to the present modification has generally the same functions and configuration as those of the test apparatus10shown inFIG. 1, so those members that have generally the same configuration and function as those of the members shown inFIG. 1will be denoted by the same reference numerals in the drawing and explanation for such members will be omitted but for any differences.
The test apparatus10according to the present modification may further comprise a search section82. In the present modification, the CPU in the system control device23executes a measuring program for measuring the current value of a current flowing through a wire, and hence makes the system control device23function as the search section82. The search section82varies the reference current IREFfrom test to test based on the judgment produced in the previous test by using a binary search method, and determines the current value (absolute value) of the current IRMflowing through the wire12.
To be more specific, the search section82first sets the reference current IREF, which takes the center value of a measurement range, which is a range of current values to be measured. Then, the search section82makes the test apparatus10perform the test. That is, the search section82makes the test apparatus10judge whether the average consumption current of the DUT200is larger than the reference current IREFor not.
Subsequently, the search section82determines to which of the upper and lower ranges within the measurement range that are divided at the level of the reference current IREFthe current IRMflowing through the wire12belongs. Then, the search section82sets the range determined to include the current IRMas a new measurement range, and sets a new reference current IREF, which takes the center value of the new measurement range. Then, the search section82repeats the above process plural times and narrows down the range to which the current IRMflowing through the wire12belongs to determine the current value (absolute value) of the current IRMflowing through the wire12.
As shown inFIG. 11for example, the search section82, for example, first sets the center of a first measurement range (for example, 0 A to 1 A) to be the reference current IREF(for example, 0.5 A). Then, the search section82makes the test apparatus10perform a first test. The search section82determines to which of a lower range (0 A to 0.5 A) and an upper range (0.5 A to 1 A), which are obtained by dividing the measurement range to upper and lower parts at the reference current IREF, the current IRMflowing through the wire12belongs, based on the judgment (a pass or a failure) obtained from the first test. In the present example, the first test turns out a failure judgment and hence the search section82determines that the current IRMbelongs to the upper range (0.5 A to 1 A).
Then, the search section82sets the determined range (0.5 A to 1 A) as a new measurement range, and sets a new reference current IREF(for example, 0.75 A), which takes the center value of the new measurement range. Then, the search section82makes the test apparatus10perform a second test and repeats the same process as that in the first test.
The search section82do the same things for the third test and thereafter. Then, the search section82narrows down the range to which the current IRMbelongs, and ultimately determines the current value of the current IRM. As obvious from the above, the test apparatus10according to the present modification can measure the absolute value of the average consumption current of the DUT200.
FIG. 12shows the configuration of the measurement apparatus20according to a second modification of the present embodiment, together with the DUT200. The measurement apparatus20according to the present modification has generally the same functions and configuration as those of the measurement apparatus20shown inFIG. 2, and thus those members that have generally the same configuration and function as those of the members shown inFIG. 2will be denoted by the same reference numerals in the drawing and explanation for such members will be omitted but for any differences.
The measurement apparatus20according to the present modification comprises a first integrating section30-1, a second integrating section integrating section, a first judging section32-1, a second judging section32-2, and a selecting outputter84instead of the integrating section30and the judging section32. Each of the first integrating section30-1and the second integrating section integrating section stores charges corresponding to a current indicating the difference between the current IRMdetected by the current detecting section28and the predetermined reference current IREFin a capacity element, and outputs the integration voltage that occurs across both the ends of the capacity element. Each of the first integrating section30-1and the second integrating section integrating section may, for example, have the configuration shown inFIG. 3.
The first judging section32-1judges whether the DUT200is a pass or a failure based on the integration voltage output from the first integrating section30. The second judging section32-2judges whether the DUT200is a pass or a failure based on the integration voltage output from the second integrating section30. Each of the first judging section32-1and the second judging section32-2may, for example, have the same configuration and function as those of the judging section32. The selecting outputter84selects and outputs the judgment output from a designated one of the first judging section32-1and the second judging section32-2.
The control section36controls the integration period and discharge period of the first integrating section30-1and second integrating section integrating section. Further, the control section36notifies the selecting outputter84of a designated one of the first judging section32-1and the second judging section32-2from which the judgment should be output.
Here, the control section36selects the first integrating section30-1and the second integrating section integrating section alternately from test to test, such that the selected one stores charges and outputs an integration value. Then, the control section36controls the second integrating section integrating section to discharge the stored charges while the first integrating section30-1is storing charges. Further, the control section36controls the first integrating section30-1to discharge the stored charges while the second integrating section integrating section is storing charges.
The measurement apparatus20according to this modification can eliminate time in which no test can be performed for the purposes of discharging. Hence, the test apparatus10having this measurement apparatus20can shorten the time taken for tests.
FIG. 13shows a configuration of a test apparatus300according to a third modification of the present invention, along with the DUT200. The test apparatus300according to the present modification has generally the same functions and configuration as those of the test apparatus10shown inFIGS. 1 to 3, so those members that have generally the same configuration and function as those of the members shown inFIGS. 1 to 3will be denoted by the same reference numerals in the drawing and explanation for such members will be omitted but for any differences.
The test apparatus300tests the DUT200and is provided with the signal generating section17, the voltage supplying section18, a measurement apparatus310, the reference voltage generating section21, the signal acquiring section22, the system control device23, and an AD converting section320. The measurement apparatus310has the same function and configuration as the measurement apparatus20. The measurement apparatus310is provided with the first capacitor24, the second capacitor26, a current detecting section330, an integrating section340, a judging section350, and a control section360. The control section360may have the same function as the setting section34and the control section36.
FIG. 14shows a configuration of the current detecting section330according to the present modification, along with the voltage supplying section18and the DUT200. The current detecting section330may include the detection resistor42, the potential difference detecting section44, and an input switching section332. The detection resistor42can be used in place of the coil. The input switching section332selects one of (i) a detection input for detecting the current IRMflowing through the wire12and (ii) a correction input that is equivalent to an input causing the current flowing through the wire12to be zero. The input causing the current flowing through the wire12to be zero may be exemplified by an input causing a short between the inputs of the potential difference detecting section44.
When the input switching section332selects the correction input, the output Vx of the potential difference detecting section44outputs the offset error. For example, when the offset of the potential difference detecting section44is 100 μV and the gain is 100, the offset error voltage is (offset)×(gain+1)=10.1 mV. If Idd is 2 A and the detection resistor42is 5 mΩ, the gain is 100, and therefore the signal output voltage is 1V. In this case, the measurement of 2 A includes an offset error voltage of approximately 1%, which is not a small error.
FIG. 15shows an exemplary configuration of the integrating section340according to the present modification. The integrating section340includes the integrating circuit50, the discharging section56, a reference current source342, a reference switching section344, and an offset correcting section346. The integrating circuit50includes the operating amplifier60and the integrating capacitor62. The integrating circuit50stores, in the integrating capacitor62, a charge corresponding to the difference in current between the reference current IREFand the current IRMdetected by the current detecting section330. This integrating capacitor62is an example of a capacity element. The integrating circuit50outputs the integration voltage VMgenerated at both ends of the capacity element as the integration value. The discharging section56includes the discharging switch72. Before beginning the test, the discharging section56discharges the charge stored in the integrating circuit50.
The reference current source342outputs the reference current IREFfrom the input of the integrating circuit50. The reference current source342includes the first voltage follower circuit64and the first reference resistor66. The second reference resistor70has the same function as the first current letting-flow section54. The reference switching section344selects whether the reference input of the reference current source342connects to the reference voltage VREFor to the ground voltage.
The offset correcting section346corrects the offset occurring at the input of the integrating circuit50. The offset correcting section346includes the correction capacitor402that stores the offset error voltage output by the current detecting section330, when the input switching section332selects the correction input and the reference switching section344selects the ground voltage, i.e. during correction. When the input switching section332selects the detection input and the reference switching section344selects the reference voltage, i.e. during measurement, the offset correcting section346outputs a voltage equal to −1 times the offset error voltage stored in the correction capacitor402. The switch404is a short during correction and is open during measurement.
As shown inFIG. 15, the offset error voltage stored in the correction capacitor402is input to the positive input of the operating amplifier400and the output is fed back to the negative input of the operating amplifier400, so that the output V1of the operating amplifier400is equal to the stored offset error voltage. On the other hand, the output V1is connected to the feedback portion of the first voltage follower circuit64via the resistance406, and therefore, if the resistance406and the resistance408have equal resistance values, the value equal to −1 times the output V1is superimposed on the output V2of the first voltage follower circuit64. This generates a reference current component that cancels out the current caused by the offset error voltage, thereby decreasing the effect of the offset error voltage.
FIG. 16shows an exemplary configuration of the judging section350according to the present modification. The judging section350includes an offset holding section352that holds the offset occurring at the output of the integrating circuit50, when the input switching section332selects the correction input and the reference switching section344selects the ground voltage, i.e. during correction. The offset holding section352includes an offset capacitor452and a switch454. The offset occurring at the output of the integrating circuit50is stored in the offset capacitor452. The switch454is a short during correction and is open during measurement.
When the input switching section332selects the detection input and the reference switching section344selects the reference voltage, i.e. during measurement, the judging section350judges whether the DUT200is defective based on the offset voltage held by the offset capacitor452of the offset holding section352. This enables correcting of the offset occurring upstream from the comparator58, so that the current can be accurately measured.
A low-voltage amplifying section354may be provided that amplifies the integration value and supplies the amplified integration value to the judging section350. Since the offset correction sets the integration value to a sufficiently low level, amplifying the integration value using the low-voltage amplifying section354has significant meaning.
The AD converting section320measures the integration value. The AD converting section320can record the digital values obtained by measuring the integration value for each measurement cycle in a recording section, measure the values obtained when only the reference current is input before or after a series of measurements, and scale the digital values of each measurement cycle recorded on the recording medium with the measured values. The recording section and the processing section that performs the scaling process may be provided to the system control device23. The AD converting section320enables the current value to be scaled by measuring the reference current only once before or after the series of measurements. This scaling is used to obtain the current value of the digital values measured in each measurement cycle.
FIG. 17shows an exemplary operation of the test apparatus300according to the third embodiment. Here, XSTSP represents the control signal of the switch404, XIN represents the control signal of the input switching section332, and XREF represents the control signal of the reference switching section344. Current measurement is performed while all of these control signals are logic L, i.e. during the period t(n). In the current measurement, the difference between the current Idd flowing through the DUT200and the reference current, shown by the dotted lines inFIG. 17, is detected as the output VM(V4) of the integrating circuit50. The defectiveness judgment is based on whether the output VM(V4) is positive or negative. Furthermore, ta represents the period over which the output VM(V4) is held, and the integration value, which is the output from the AD converting section320, is acquired during this period. The acquired integration value is scaled with the integration value of only the reference current measured during the period t(ref).
One aspect of the present invention has been explained above using an embodiment, but the technical scope of the present invention is not limited to the scope described in the above embodiment. Various modifications or alterations can be made upon the above-described embodiment. It is obvious from the claims that any embodiment upon which such modifications or alterations are made can also be included in the technical scope of the present invention.
|
FR 1093211 A1
|
Method of controlling playback condition, optical disk, optical disk drive device and program
Playback durability of a writable optical disk is ensured. A method of controlling a playback condition includes continuously irradiating an optical disk with a laser beam having a power level lower than a mark formation level and detecting a change of a state of a signal caused by a return light from the optical disk, and setting a playback condition for the optical disk according to the change of the state of the signal. The playback durability of the optical disk can be ensured by adaptively controlling the playback condition as stated above.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a technique for preventing or suppressing degradation of a recorded state of a writable optical disk in an optical disk drive device.
2. Description of the Related Art
For example, JP-A-2006-309921 discloses an evaluation method of an optical recording medium in which the evaluation of playback durability of the optical recording medium can be performed in a short time and with high precision. Specifically, an operation laser power for heating a recording layer up to a recording operation temperature is obtained; the temperature of the recording layer when a laser beam having a specified playback laser power is irradiated at data playback is obtained based on the ambient temperature at the data playback, the playback laser power and the operation laser power; a relation between the playback laser power at the data playback and a playback endurance frequency is obtained; and a relation between the temperature of the recording layer at the data playback and the playback endurance frequency is obtained from the relation between the playback laser power at the data playback and the playback endurance frequency. However, no consideration is made on measures to enable the playback while the durability is kept.
In order to play back information recorded on an optical disk, a laser beam having a playback power is irradiated to the optical disk. According to standards, the disk must withstand more than one million times laser irradiation than the playback power. Until now, no serious problem occurs in CDs and DVDs. However, when a laser of a shorter wavelength is used for a high capacity optical disk based on the Blu-ray standard or HD-DVD standard, there is a tendency that even if the amount of power output is small like the playback power as compared with the record power, the laser has the energy amount to disrupt coloring matter coupling. Thus, in a writable optical disk, the state of recorded medium becomes liable to degrade by repeated playback, and the problem of the playback durability becomes serious.
It is ideal that in combinations of all commercialized optical disk drives and optical disks themselves, sufficient playback durability is obtained, and playback degradation does not occur in any playback environment, or does not reach such a level that a problem occurs in a recording and playback system. However, actually, the lasers of the optical disk drives and the optical disks have individual variations at the time of production and due to change over lapsed time, and the change of outside environment such as temperature also has an influence. Therefore, according to the related art, it is difficult to ensure a sufficient margin.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a technique for ensuring playback durability of a writable optical disk.
According to a first aspect of the invention, a method of controlling a playback condition includes a step of continuously irradiating an optical disk with a laser beam having a power level lower than a mark formation level and detecting a change of a state of a signal caused by a return light from the optical disk, and a step of changing and setting a playback condition for the optical disk according to the change of the state of the signal. The playback condition is adaptively controlled as stated above, so that the playback durability of the optical disk can be ensured.
According to a second aspect of the invention, a method of controlling a playback condition includes a step of irradiating a track of an optical disk with a laser beam having a power level lower than a mark formation level and detecting a state of an initial signal as a state of a signal caused by a return light from the track of the optical disk, a step of continuously irradiating the track of the optical disk with a laser beam having a power level lower than the mark formation level for a specified time or a specified number of times and detecting a state of a second signal as a state of a signal caused by a return light from the track of the optical disk, a step of calculating a variation or a rate of change of a state of a signal based on the state of the initial signal and the state of the second signal, a step of using data representing a relation between a variation or a rate of change of a state of a signal and a compensation amount of a playback condition for the optical disk and specifying the compensation amount of the playback condition corresponding to the calculated variation or the rate of change of the state of the signal, and a step of setting a playback condition in which the specified compensation amount of the playback condition is reflected. As the variation or the rate of change of the state of the signal becomes large, the playback durability of this optical disk becomes low. Accordingly, when the data representing the relation between the variation or the rate of change of the state of the signal and the compensation amount of the playback condition for the optical disk is prepared, an adjustment can be made to the suitable playback condition, and the playback durability can be ensured.
According to a third aspect of the invention, a method of controlling a playback condition includes a first detection step of irradiating a track of an optical disk with a laser beam having a power level lower than a mark formation level and detecting a state of an initial signal as a state of a signal caused by a return light from the track of the optical disk, a second detection step of continuously irradiating the track of the optical disk with a laser beam having a power level lower than the mark formation level and detecting a state of a second signal as a state of a signal caused by a return light from the track of the optical disk, a step of calculating a variation or a rate of change of a state of a signal based on the state of the initial signal and the state of the second signal, a step of, when the variation or the rate of change of the state of the signal exceeds a threshold, using data representing a relation between a time or a laser irradiation frequency and a compensation amount of a playback condition for the optical disk and specifying the compensation amount of the playback condition corresponding to the time between the first detection step and the second detection step or the laser irradiation frequency, and a step of setting a playback condition in which the specified compensation amount of the playback condition is reflected. Here, the laser irradiation frequency may be the number of times the disk makes one rotation and the laser beam is repeatedly irradiated to the same position. It is understood that when the variation or the rate of change of the state of the signal exceeds the specified threshold before the laser irradiation time or the laser irradiation frequency becomes large, the playback durability of this optical disk is low. Accordingly, when the data representing the relation between the time or the laser irradiation frequency and the compensation amount of the playback condition for the optical disk is prepared, an adjustment can be made to the suitable playback condition, and the playback durability can be ensured.
According to a fourth aspect of the invention, a method of controlling a playback condition includes a step of recording data on a track of an optical disk under a recording condition, a step of irradiating the track with a laser beam having a power level lower than a mark formation level and detecting a state of an initial signal as a state of a signal caused by a return light from the track, a step of continuously irradiating the track of the optical disk with a laser beam having a power level lower than the mark formation level for a specified time or a specified number of times and detecting a state of a second signal as a state of a signal caused by a return light from the track of the optical disk, a step of calculating a variation or a rate of change of a state of a signal based on the state of the initial signal and the state of the second signal, a step of using data representing a relation between a variation or a rate of change of a state of a signal and a compensation amount of a playback condition for the optical disk and specifying the compensation amount of the playback condition corresponding to the calculated variation or the rate of change of the state of the signal, and a step of setting a playback condition in which the specified compensation amount of playback condition is reflected. For example, a code pattern is actually recorded in a test recording area, and the variation or the rate of change of the state of the signal can be acquired in an environment close to actual playback. That is, the adjustment of the playback condition can be performed more appropriately.
According to a fifth aspect of the invention, a method of controlling a playback condition includes a step of recording data on a track of an optical disk under a recording condition, a first detection step of irradiating the track with a laser beam having a power level lower than a mark formation level and detecting a state of an initial signal as a state of a signal caused by a return light from the track, a second detection step of continuously irradiating the track with a laser beam having a power level lower than the mark formation level and detecting a state of a second signal as a state of a signal caused by a return light from the track, a step of calculating a variation or a rate of change of a state of a signal based on the state of the initial signal and the state of the second signal, a step of, when the variation or the rate of change of the state of the signal exceeds a threshold, using data representing a relation between a time or a laser irradiation frequency and a compensation amount of a playback condition for the optical disk and specifying the compensation amount of the playback condition corresponding to the time between the first detection step and the second detection step or the laser irradiation frequency, and a step of setting a playback condition in which the specified compensation amount of the playback condition is reflected.
Besides, the state of the signal of the first to the third aspects of the invention may be a reflectivity level. Besides, the state of the signal of the first, the fourth and the fifth aspects of the invention may be one of a voltage level of a code in the data recording, a β value, an asymmetry value, a jitter value and an error value.
Further, the playback condition may be a level of a laser power at playback or a rotational speed of a spindle motor.
According to a sixth aspect of the invention, a method of controlling a playback condition includes a step of reading information relating to a change of a state of a signal caused by a return light from an optical disk, which is generated as a result of continuously irradiating the optical disk with a laser beam having a power level lower than a mark formation level, from a memory in an optical disk drive or the optical disk in which the information relating to the change of the state of the signal is stored, and a step of changing and setting a playback condition for the optical disk according to the information relating to the change of the state of the signal. As stated above, the information relating to the change of the state of the signal may not be calculated by the optical disk drive device, but may be read from the memory in the optical disk drive device or the optical disk. Incidentally, the playback condition in which the playback durability is considered may be read from the memory in the optical disk drive device or the optical disk and may be set.
According to a seventh aspect of the invention, an optical disk records data representing a relation between a variation or a rate of change of a state of a signal caused by a return light from an optical disk, which is generated as a result of continuously irradiating the optical disk with a laser beam having a power level lower than a mark formation level, and a compensation amount of a playback condition for the optical disk. When the optical disk as stated above is prepared, the processes as described above can be performed, the suitable playback condition is set, and the playback durability can be ensured.
According to an eighth aspect of the invention, an optical disk records data representing a relation between a time or a laser irradiation frequency, from a laser irradiation start, obtained when a variation or a rate of change of a state of a signal caused by a return light from a track, which is generated as a result of continuously irradiating the optical disk with a laser beam having a power level lower than a mark formation level, exceeds a threshold and a compensation amount of a playback condition for the optical disk.
According to a ninth aspect of the invention, an optical disk drive device includes a memory that stores data representing a relation between a variation or a rate of change of a state of a signal caused by a return light from an optical disk, which is generated as a result of continuously irradiating the optical disk with a laser beam having a power level lower than a mark formation level, and a compensation amount of a playback condition for the optical disk.
According to a tenth aspect of the invention, an optical disk drive device includes a memory that stores data representing a relation between a time or a laser irradiation frequency, from a laser irradiation start, obtained when a variation or a rate of change of a state of a signal caused by a return light from a track, which is generated as a result of continuously irradiating an optical disk with a laser beam having a power level lower than a mark formation level, exceeds a threshold and a compensation amount of a playback condition for the optical disk.
According to an eleventh aspect of the invention, an optical disk stores at least one of information relating to a change of a state of a signal caused by a return light from an optical disk, which is generated as a result of continuously irradiating the optical disk with a laser beam having a power level lower than a mark formation level, and a data playback condition for the optical disk. By doing so, the processes as described above can be performed, the suitable playback condition is set, and the playback durability can be ensured.
According to a twelfth aspect of the invention, an optical disk drive device includes a memory that stores at least one of information relating to a change of a state of a signal caused by a return light from an optical disk, which is generated as a result of continuously irradiating the optical disk with a laser beam having a power level lower than a mark formation level, and a data playback condition that is determined according to the change of the state of the signal and can prevent or suppress degradation of playback quality of the optical disk.
A program for causing a processor to execute a method of the invention can be created, and the program is stored in, for example, a storage medium or a storage device such as a flexible disk, an optical disk such as a CD-ROM, a magneto-optical disk, a semiconductor memory, a hard disk, a nonvolatile memory of a processor, or any other computer readable medium. Besides, the program may be distributed by digital signals through a network. Incidentally, the data in the middle of processing may be temporarily stored in a storage device such as a memory of a processor.
According to the invention, the playback durability of a writable optical disk can be ensured.
DETAILED DESCRIPTION OF THE INVENTION
A drive system of a first embodiment of the invention will be described with reference to a functional block diagram ofFIG. 1. The drive system of the embodiment of the invention includes an optical disk drive device100and an I/O system (not shown) including a display unit such as a television set and an operation unit such as a remote controller.
The optical disk drive device100includes a memory127for storing data in the middle of processing, data of processing results, reference data in the processing, and the like, a controlling circuit125including a CPU (Central Processing Unit) and a memory circuit126for storing a program to cause a process described later to be performed, an interface unit (hereinafter abbreviated to an I/F)128as an interface to the I/O system, a characteristic value detection unit124to detect an amplitude level of an RF signal as a playback signal, an equalizer131and a data demodulator circuit123for performing a process to decode that a code of which length is read from the RF signal as the playback signal, a pickup unit110, a data modulator circuit129that performs a specified modulation on data outputted from the controlling circuit125and to be recorded and outputs it to a laser diode (hereinafter abbreviated to an LD) driver121, the LD driver121, and a servo controlling circuit132for a rotational control unit of an optical disk150and a spindle motor133and for the pickup unit110. Incidentally, the length of the code read from the RF signal is, for example, 2T to 8T and 9T of a synchronous code in the case of Blu-ray standards. Besides, in the case of HD-DVD standards, the length is 2T to 11T and 13T of a synchronous code.
The pickup unit110includes an objective lens114, a beam splitter116, a detection lens115, a collimate lens113, an LD111, and a photo detector (PD)112. In the pickup unit110, a not-shown actuator is operated according to the control of the servo controlling circuit132, and focusing and tracking are performed.
The controlling circuit125is connected to the memory127, the characteristic value detection unit124, the I/F128, the LD driver121, the data modulator circuit129, the servo controlling circuit132and the like. The characteristic value detection unit124is connected to the PD112, the controlling circuit125and the like. The LD driver121is connected to the data modulator circuit129, the controlling circuit125and the LD111. The controlling circuit125is connected also to the I/O system through the I/F128.
Next, the outline of a process when data is recorded on the optical disk150will be described. First, the controlling circuit125causes the data modulator circuit129to perform the specified modulation processing on the data to be recorded on the optical disk150, and the data modulator circuit129outputs the modulated data to the LD driver121. Incidentally, the controlling circuit125controls the spindle motor133to rotate at a specified rotational speed through the servo controlling circuit132. The LD driver121drives the LD111based on the received data and in accordance with a specified recording condition (strategy and parameter) and causes the laser beam to be outputted. The laser beam is irradiated to the disk150through the collimate lens113, the beam splitter116, and the objective lens114, and forms a mark and a space on the optical disk150. Incidentally, in this embodiment, the optical disk drive device100may be such that data can not be recorded.
Besides, the outline of a process when data recorded on the optical disk150is played back will be described. In accordance with the instruction from the controlling circuit125, the LD driver121drives the LD111to output a laser beam. The controlling circuit125controls the spindle motor133to rotate at a specified rotational speed through the servo controlling circuit132. The laser beam is irradiated to the optical disk150through the collimate lens113, the beam splitter116, and the objective lens114. The reflected light from the optical disk150is inputted to the PD112through the objective lens114, the beam splitter116and the detection lens115. The PD112converts the reflected light from the optical disk150into an electric signal and outputs it to the characteristic value detection unit124and the like. The equalizer131and the data demodulator circuit123perform a specified decoding processing on the outputted playback signal, and outputs the decoded data to the display unit of the I/O system through the controlling circuit125and the I/F128, and the playback data is displayed. The characteristic value detection unit124is not used in normal playback.
Next, the process of the embodiment will be described with reference toFIGS. 2 to 5. First, the user sets the optical disk150(optical disk on which data can be written at least once) to optical disk drive device100. The controlling circuit125reads initialization information, such as a data playback position (for example, a specified track in a test area), a laser power level and a rotational speed of the spindle motor133, previously stored in the memory127or the like, and sets it in the LD driver121, the servo controlling circuit132and the like (step S1). Although the laser power level is set to a value lower than a recording laser power level, that is, a mark formation level, it is preferable that a value higher than a normal playback laser power level is adopted. This is for causing a change of a playback signal described later to occur in a short time. Besides, a specified code may not be written at the data playback position.
Next, the controlling circuit125causes the LD driver121to start laser irradiation to the foregoing data playback position (step S3). The laser irradiation is continuously performed. When the laser irradiation is started, a return (reflected) light from the optical disk150is converted into an electric signal by the PD112, and is outputted to the characteristic value detection unit124. The characteristic value detection unit124detects a state of a signal caused by the return light, and outputs it to the controlling circuit125, and the controlling circuit125stores it in the memory127(step S5). Step S5is performed at least twice, that is, immediately after step S3and after a specified time elapses or laser irradiation is performed a specified number of times. However, the change mode of the state of the signal, for example, a linear type, a saturation type, or an exponential function type may be determined by performing step S5more times.
Incidentally, when playback degradation does not occur, as shown by a solid line “Ref.” in the graph ofFIG. 3(the vertical axis represents voltage level, and the horizontal axis represents time), an almost constant voltage level is detected by the characteristic value detection unit124. The voltage level approximately represents the reflectivity level of the optical disk150, and here, it is indicated that the reflectivity is constant. On the other hand, when the signal degradation occurs by repeated playback, the voltage level is changed. In general, when the optical disk150is of the Low-to-High type, the voltage level is changed to the high voltage side as indicated by a dotted line. When the optical disk150is of the High-to-Low type, the voltage level is changed to the low voltage side as indicated by an alternate long and short dash line. That is, the reflectivity is changed.
Incidentally, the voltage level based on the return light from the optical disk150may not directly be used, but another index may be calculated, and the index value may instead be used as the state of the signal.
Accordingly, the voltage level detected immediately after step S3is stored as a state of a reference signal or a state of an initial signal in the memory127, and it is determined what signal state is obtained after a specified time elapses.
At the time point when the detection at step S5is ended, the controlling circuit125causes the LD driver121to end the laser irradiation. The controlling circuit125derives the variability of the detected state of the signal (step S7). Specifically, a difference between a first voltage level as the state of the reference signal (the state of the initial signal) and a second voltage level as a state of a signal (a second state of a signal) after the specified time elapses, that is, a variation or a rate of change is calculated. For example, the rate of change may be calculated as (first voltage level−second voltage level)/(first voltage level). Also as described above, the change mode of the state of the signal may also be determined.
Thereafter, the controlling circuit125specifies a compensation amount of a playback condition corresponding to the derived variability of the state of the signal (step S9). For example, a correspondence table of a variability of a state of a signal and a compensation amount to be applied, or data of an expression to calculate a compensation amount to be applied from a variability of a state of a signal is stored in the memory127, and the compensation amount corresponding to the derived variability of the state of the signal is specified by using the correspondence table or the expression. When the variability includes the change mode, for example, correspondence tables or expressions corresponding to respective types are prepared. Incidentally, also described later, the correspondence table or the expression may be recorded on the optical disk150, not the memory127, and may be read from the optical disk150.
For example, a system may be adopted in which with respect to the optical disk150having high playback degradation, it is necessary to reduce the playback laser power level; however, with respect to the optical disk150having little playback degradation, the laser power level is not much reduced. Specifically, as shown in the graph ofFIG. 4(the vertical axis represents the compensation amount of playback power, and the horizontal axis represents the amount of signal state transition), the relation between the amount of signal state transition and the compensation amount of playback power is expressed by a downward-sloping curve. This is because, since it is assumed that the compensation amount is added to the normal playback condition, it becomes large in the negative direction. That is, when the amount of signal state transition increases, the absolute value of the compensation amount of playback power increases. When the amount of signal state transition is a threshold or less, it is unnecessary to change the playback power, and therefore, the compensation amount is 0. When the compensation amount is made excessively large, the C/N ratio of the playback signal at the data playback deteriorates, and therefore, it is preferable that the upper limit of the compensation is also set. Incidentally, the curve shown in the graph ofFIG. 4is merely an example, and there is also a case where the compensation amount is represented by another shape curve.
Besides, a system may be adopted in which with respect to the optical disk150having high playback degradation, the rotational speed or the rotating speed of the spindle motor133is increased to shorten the time of laser irradiation, and with respect to the optical disk150having little playback degradation, the rotational speed of the spindle motor133is not increased very much. Specifically, as shown in the graph ofFIG. 5(the vertical axis represents the compensation amount of rotational speed of playback spindle, and the horizontal axis represents the amount of signal state transition), the relation between the amount of signal state transition and the compensation amount of rotational speed of playback spindle is expressed by an upward-sloping curve. Incidentally, when the amount of signal state transition is a threshold or less, it is unnecessary to change the rotational speed of the spindle motor133, and therefore, the compensation amount is 0. When the compensation amount is made excessively large, the C/N ratio of the playback signal at the data playback deteriorates, and therefore, it is preferable that the upper limit of the compensation amount is also set. Incidentally, the curve shown in the graph ofFIG. 5is merely an example, and there is also a case where the compensation amount is expressed by another shape curve.
As stated above, although the playback condition is the laser power level at the playback or the rotational speed of the spindle motor133, another playback condition may be adjusted. Besides, the relation as shown inFIG. 4orFIG. 5may be held as data in a table form or in an expression form.
The controlling circuit125sets the playback condition, in which the specified compensation amount of the playback condition is reflected on the normal playback condition, in the LD driver121or the servo controlling circuit132(step S11). That is, the compensation amount is added to the normal playback condition to specify the playback condition for subsequent data playback. When the laser power level is the playback condition, the specified playback condition is set in the LD driver121. When the rotational speed of the spindle motor133is the playback condition, the specified playback condition is set in the servo controlling circuit132.
The process as stated above may be performed before the data playback is performed, so that the playback degradation can be prevented or suppressed. That is, the playback durability of the data writable optical disk150can be ensured.
A functional block diagram of a drive system of a second embodiment of the invention is the same as that of the first embodiment shown inFIG. 1. However, a process as shown inFIG. 6is performed.
First, the user sets an optical disk150(optical disk on which data can be written at least once) to an optical disk drive device100. A controlling circuit125reads initialization information, such as a data playback position (for example, a specified track in a test area), a laser power level and a rotational speed of a spindle motor133, previously stored in a memory127or the like, and sets it in an LD driver121, a servo controlling circuit132and the like (step S21). Although the laser power level is set to a value lower than a recording laser power level, that is, a mark formation level, it is preferable that a value higher than a normal playback laser power level is adopted. Besides, a specified code may not be written at the data playback position.
Next, the controlling circuit125causes the LD driver121to start laser irradiation to the data playback position (step S23). The laser irradiation is continuously performed. When the laser irradiation is started, a return (reflected) light from the optical disk150is converted into an electric signal by a PD112, and is outputted to a characteristic value detection unit124. The characteristic value detection unit124detects a state of a signal caused by the return light, and outputs it to the controlling circuit125, and the controlling circuit125stores it in the memory127(step S25). The state of the signal is the same as that explained in the first embodiment. First, the state of the signal immediately after step S23is detected as a state of a reference signal or a state of an initial signal. Besides, measurement of an elapsed time or counting of a laser irradiation frequency is started from the first execution of step S23.
The controlling circuit125determines whether the elapsed time reaches a specified time or the laser irradiation frequency reaches a specified number of times (step S27). When the elapsed time does not reach the specified time, or the laser irradiation frequency does not reach the specified number of times, return is made to step S25. On the other hand, when the elapsed time reaches the specified time, or the laser irradiation frequency reaches the specified number of times, the controlling circuit125causes the LD driver121to end the laser irradiation. The controlling circuit125derives a variability of the detected state of the signal (step S29). Specifically, a difference between a first voltage level as the state of the reference signal (the state of the initial signal) and a second voltage level as a state of a signal (a second state of a signal) after the specified time elapses, that is, a variation or a rate of change is calculated. For example, the rate of change may be calculated as (first voltage level−second voltage level)/(first voltage level). As described in the first embodiment, the change mode of the state of the signal may also be determined.
Thereafter, the controlling circuit125specifies a compensation amount of a playback condition corresponding to the derived variability of the state of the signal (step S31). For example, a correspondence table of a variability of a state of a signal and a compensation amount to be applied, or data of an expression to calculate a compensation amount to be applied from a variability of a state of a signal is stored in the memory127, and the compensation amount corresponding to the derived variability of the state of the signal is specified by using the correspondence table or the expression. When the variability includes the change mode, for example, correspondence tables or expressions corresponding to respective types are prepared. Incidentally, the correspondence table or the expression may be recorded on the optical disk150, not the memory127, and may be read from the optical disk150. Step S31is also similar to step S9in the first embodiment.
Similarly to the first embodiment, the playback condition is the laser power level at playback or the rotational speed of the spindle motor133, however, another playback condition may be adjusted.
The controlling circuit125sets the playback condition, in which the specified compensation amount of the playback condition is reflected on the normal playback condition, in the LD driver121or the servo controlling circuit132(step S33). That is, the compensation amount is added to the normal playback condition to specify the playback condition for subsequent data playback. When the laser power level is the playback condition, the playback condition is set in the LD driver121. When the rotational speed of the spindle motor133is the playback condition, the playback condition is set in the servo controlling circuit132.
The process as stated above may be performed before the data playback is performed, so that the playback degradation can be prevented or suppressed. That is, the playback durability of the data writable optical disk150can be ensured.
A functional block diagram of a drive system of a third embodiment of the invention is the same as that of the first embodiment shown inFIG. 1. However, a process as shown inFIG. 7is performed.
First, the user sets an optical disk150(optical disk on which data can be written at least once) to an optical disk drive device100. A controlling circuit125reads initialization information, such as a data playback position (for example, a specified track in a test area), a laser power level and a rotational speed of a spindle motor133, previously stored in a memory127or the like, and sets it in an LD driver121, a servo controlling circuit132and the like (step S41). Although the laser power level is set to a value lower than a recording laser power level, that is, a mark formation level, it is preferable that a value higher than a normal playback laser power level is adopted. Besides, a specified code may not be written at the data playback position.
Next, the controlling circuit125causes the LD driver121to start laser irradiation to the foregoing data playback position (step S43). The laser irradiation is continuously performed. When the laser irradiation is started, a return (reflected) light from the optical disk150is converted into an electric signal by a PD112, and is outputted to a characteristic value detection unit124. The characteristic value detection unit124detects a state of a signal caused by the return light, and outputs it to the controlling circuit125, and the controlling circuit125stores it in a memory127(step S45). The state of the signal is the same as that explained in the first embodiment. First, the state of the signal immediately after step S43is detected as a state of a reference signal or a state of an initial signal. Besides, measurement of an elapsed time or counting of a laser irradiation frequency is started from the first execution of step S43.
The controlling circuit125determines whether the state of the signal reaches a target level (step S47). In the case of the Low-to-High optical disk150, the target level is a level in which a specified rate α (for example, 5%) is added to the state of the reference signal. In the case of the High-to-Low optical disk150, the target level is a level in which the state of the reference signal is reduced by the specified rate α. That is, it is determined whether the playback degradation occurs, and whether the state of the signal is changed from the state of the reference signal by the specified rate α or more.
When the state of the signal does not reach the target level, the controlling circuit125determines whether the elapsed time reaches a specified time or the laser irradiation frequency reaches a specified number of times (step S49). When the elapsed time does not reach the specified time or the laser irradiation frequency does not reach the specified number of times, return is made to step S45. On the other hand, when the elapsed time reaches the specified time or the laser irradiation frequency reaches the specified number of times, since the playback degradation is low, even if the specified time or the specified number of times is attained, the state of the signal is not changed to the target level. In that case, the laser irradiation is stopped and shift is made to step S51.
When the state of the signal reaches the target level, the controlling circuit125causes the LD driver121to end the laser irradiation. The controlling circuit125derives a playback durability index of the optical disk150(step S51), as will be described below.
As indicated by a curve “a” or “b” in the graph ofFIG. 8(the vertical axis represents normalized voltage, and the horizontal axis represents time or frequency), in the case of the Low-to-High optical disk150, when the playback degradation occurs, as the laser irradiation time or the frequency increases, the voltage rises. In the case of the optical disk150which is liable to be subjected to playback degradation, as indicated by the curve “b”, a time “b” (called degradation time) or a frequency “b” (called deterioration frequency) required to reach the target level (for example, 1+α) becomes short. On the other hand, in the case of the optical disk150which is not easily subjected to playback degradation, as indicated by the curve “a”, the degradation time “a” or the deterioration frequency “a” required to reach the target level (for example, 1+α) becomes larger. Accordingly, the degradation time and/or the deterioration frequency can be used as a playback durability index. Also in the case of the High-to-Low optical disk150, the degradation time and/or the deterioration frequency can be used as the playback durability index.
However, when it is determined at step S49that the specified time or the specified frequency is attained, a value obtained by adding a suitable value (which may include 0) to the specified time or the specified frequency may be used as a degradation time or a deterioration frequency.
Thereafter, the controlling circuit125specifies a compensation amount of a playback condition corresponding to the derived playback durability index (step S53). For example, a correspondence table of a playback durability index and a compensation amount to be applied, or data of an expression to calculate a compensation amount to be applied from a playback durability index is stored in the memory127, and the compensation amount corresponding to the derived playback durability index is specified by using the correspondence table or the expression. Incidentally, the correspondence table or the expression may be recorded on the optical disk150, not the memory127, and may be read from the optical disk150.
When the playback condition is the laser power, the compensation amount as shown inFIG. 9is specified. In the graph ofFIG. 9, the vertical axis represents the compensation amount of playback power, and the horizontal axis represents playback durability index. As shown in the figure, as the playback durability index becomes a small value, the absolute value of the compensation amount of the playback power becomes large. When the playback durability index increases, the absolute value of the compensation amount of the playback power decreases proportionally, and when the playback durability index increases to a certain degree, the compensation amount of the playback power becomes 0. Incidentally, when the compensation amount is made excessively large, the C/N ratio of the playback signal at data playback deteriorates, and therefore, it is preferable that the upper limit of the compensation amount is also set. Incidentally, the curve ofFIG. 9is merely an example, and there is also a case where the compensation amount is expressed by another shape curve.
When the playback condition is the rotational speed or the rotating speed of the spindle motor133, the compensation amount as shown inFIG. 10is specified. InFIG. 10, the vertical axis represents the compensation amount of rotational speed of playback spindle, and the horizontal axis represents playback durability index. As shown in the figure, when the playback durability index becomes a small value, the compensation amount of rotational speed of playback spindle becomes a large value. When the playback durability index increases, the compensation amount of rotational speed of playback spindle approaches 0 according to that. When the playback durability index increases to a certain degree, the compensation amount of rotational speed of playback spindle becomes 0. Incidentally, when the compensation amount is made excessively large, the C/N ratio of the playback signal at data playback deteriorates, and therefore, it is preferable that the upper limit of the compensation amount is also set. Incidentally, the curve ofFIG. 10is an example, and there is also a case where the compensation amount is expressed by another shape curve.
The controlling circuit125sets the playback condition, in which the specified compensation amount of the playback condition is reflected, in the LD driver121or the servo controlling circuit132(step S55). That is, the compensation amount is added to the normal playback condition to specify the playback condition for subsequent data playback. When the laser power level is the playback condition, the playback condition is set in the LD driver121. When the rotational speed of the spindle motor133is the playback condition, the playback condition is set in the servo controlling circuit132.
The process as stated above may be performed before the data playback is performed, so that the playback degradation can be prevented or suppressed. That is, the playback durability of the data writable optical disk150can be ensured.
A functional block diagram of a drive system of a fourth embodiment of the invention is the same as that of the first embodiment shown inFIG. 1. In the first to the third embodiments, a laser beam is irradiated to an area where data is not recorded, and the degree of playback degradation can be artificially specified when no recording is performed. In this embodiment, a method is described in which test recording is performed to actually write a specified code, and playback is performed to actually specify the degree of playback degradation. Hereinafter, a process will be described with reference toFIG. 11andFIG. 12. Of course, recording may be performed with the first to third embodiments as well.
First, the user sets an optical disk150(optical disk on which data can be written at least once) to an optical disk drive device100. A controlling circuit125reads initialization information, such as a data recording position (for example, a specified track in a test area), a recording laser power level, a playback laser power level, and a rotational speed of the spindle motor133, previously stored in a memory127or the like, and sets it in an LD driver121, a servo controlling circuit132and the like (step S61). Although the playback laser power level is set to a value lower than a recording laser power level, that is, a mark formation level, it is preferable that a value higher than a normal playback laser power level is adopted.
Next, the controlling circuit125outputs a specified sign row to a data modulator circuit129, and causes the specified sign row to be recorded on a specified track of the optical disk150through the LD driver121and an LD111(step S63).
The controlling circuit125causes the LD driver121to start laser irradiation to the specified track at the playback laser power level which is set as described above and to start data playback (step S65). The laser irradiation is continuously performed. When the laser irradiation is started, a return (reflected) light from the optical disk150is converted into an electric signal by a PD112, and is outputted to a characteristic value detection unit124. The characteristic value detection unit124detects a signal state of a playback signal caused by the return light and outputs it to the controlling circuit125.
For example, voltage levels of playback signals (2T to 8T signs) in the case of Low-to-High of Blu-ray standards are as shown inFIG. 12. InFIG. 12, the vertical axis represents voltage, and the horizontal axis represents time. In the case of the Low-to-High type, when a 2T mark is played back, a I2H level can be obtained, and when a 2T space is played back, a I2L level can be obtained. When a 3T mark is played back, a I3H level can be obtained, and when a 3T space is played back, a I3L level can be obtained. When a 8T mark is played back, a I8H level can be obtained, and when a 8T space is played back, a I8L level can be obtained. When playback degradation occurs by repeatedly performing the data playback, similarly to the first to the third embodiments, these voltage levels are changed to the high voltage side when the optical disk150is of the Low-to-High type, or are changed to the low voltage side when the optical disk150is of the Low-to-High type. Incidentally, the variation amount often varies according to the sign, the balance between the signs is lost, and the recording quality deteriorates. Then, for example, with respect to one sign, a voltage level (also called an amplitude level) is detected by the characteristic value detection unit124, and may be directly adopted as a signal state evaluation index. Voltage levels are detected with respect to plural signs, an operation is performed on those values, and a signal state evaluation value may be calculated.
Besides, in addition to the simple voltage level, an evaluation index such as a β value, an asymmetry value, a jitter value or an error value known to those skilled in the art may be adopted as the signal state evaluation index. In such a case, characteristic values required to calculate such known values by the controlling circuit125are detected by the characteristic value detection unit124, and are outputted to the controlling circuit125.
The controlling circuit125uses the output from the characteristic value detection unit124, calculates a previously determined signal state evaluation index, and stores it in the memory127(step S67). The value of the signal state evaluation index calculated immediately after step S65is performed is treated as a reference value or a starting value.
Besides, measurement of an elapsed time or counting of a laser irradiation frequency is started from the execution of step S65.
The controlling circuit125determines whether the elapsed time reaches a specified time or the laser irradiation frequency reaches a specified number of times (step S69). When the elapsed time does not reach the specified time, or the laser irradiation frequency does not reach the specified number of times, return is made to step S67. On the other hand, when the elapsed time reaches the specified time, or the laser irradiation frequency reaches the specified number of times, the controlling circuit125causes the LD driver121to end the laser irradiation. The controlling circuit125derives the variability of the signal state evaluation index (step S71). Specifically, a difference between the reference value (state of an initial signal) of the signal state evaluation index and the value (state of a second signal) of the signal state evaluation index calculated at step S67performed lastly, that is, a variation or a rate of change is calculated. For example, a rate of change may be calculated as (the state of the initial signal−the state of the second signal)/(the state of the initial signal). Also, a change mode, such as a shape of a change curve of a signal state evaluation index, may also be specified.
Thereafter, the controlling circuit125specifies a compensation amount of a playback condition corresponding to the derived variability of the signal state evaluation index (step S73). For example, a correspondence table of a variability of a signal state evaluation index and a compensation amount to be applied, or data of an expression to calculate a compensation amount to be applied from a variability of a signal state evaluation index is stored in the memory127, and the compensation amount corresponding to the derived variability of the signal state evaluation index is specified by using the correspondence table or the expression. When the variability includes the change mode, correspondence tables or expressions corresponding to respective types are prepared. Incidentally, the correspondence table or the expression may be recorded on the optical disk150, not the memory127, and may be read from the optical disk150.
Similarly to the first embodiment, the playback condition is the laser power level at playback or the rotational speed of the spindle motor133. Accordingly, the relation between the amount of the signal state transition and the compensation amount of the playback power shown inFIG. 4is similar to the relation between the variability of the signal state evaluation index and the compensation amount of the playback power. Similarly, the relation between the amount of the signal state transition and the compensation amount of the rotational speed of the playback spindle shown inFIG. 5is similar to the relation between the variability of the signal state evaluation index and the compensation amount of the rotational speed of the playback spindle.
Similarly to the first embodiment, although the playback condition is the laser power level at playback or the rotational speed of the spindle motor133, another playback condition may be adjusted.
The controlling circuit125sets the playback condition, in which the specified compensation amount of the playback condition is reflected on the normal playback condition, in the LD driver121or the servo controlling circuit132(step S75). That is, the compensation amount is added to the normal playback condition to specify the playback condition for subsequent data playback. When the laser power level is the playback condition, the playback condition is set in the LD driver121. When the rotational speed of the spindle motor133is the playback condition, the playback condition is set in the servo controlling circuit132.
The process as stated above may be performed before the data playback is performed, so that the playback degradation can be prevented or suppressed. That is, the playback durability for the data writable optical disk150can be ensured.
A functional block diagram of a drive system of a fifth embodiment of the invention is the same as that of the first embodiment shown inFIG. 1. Also in this embodiment, test recording is performed to actually write a code, and playback is performed to actually specify the degree of playback degradation. Hereinafter, a process will be described with reference toFIG. 13.
First, the user sets an optical disk150(optical disk on which data can be written at least once) to an optical disk drive device100. A controlling circuit125reads initialization information, such as a data recording position (for example, a specified track in a test area), a recording laser power level, a playback laser power level, and a rotational speed of the spindle motor133, previously stored in a memory127or the like, and sets it in an LD driver121, a servo controlling circuit132or the like (step S81). Although the playback laser power level is set to a value lower than a recording laser power level, that is, a mark formation level, it is preferable that a value higher than a normal playback laser power level is adopted.
Next, the controlling circuit125outputs a specified sign row to a data modulator circuit129, and causes the specified sign row to be recorded on the specified track of the optical disk150through the LD driver121and an LD111(step S83).
The controlling circuit125causes the LD driver121to start laser irradiation to the specified track at the playback laser power level which is set as described above and to start data playback (step S85). The laser irradiation is continuously performed. When the laser irradiation is started, a return (reflected) light from the optical disk150is converted into an electric signal by the PD112, and is outputted to a characteristic value detection unit124. The characteristic value detection unit124detects a signal state of a playback signal caused from the return light and outputs it to the controlling circuit125. This process is the same as that of step S65of the fourth embodiment. That is, for example, a voltage level is detected by the characteristic value detection unit124with respect to one sign, and may be directly used as the signal state evaluation index. Voltage levels are detected with respect to plural signs, and an operation may be performed on those values to calculate the signal state evaluation value. Besides, in addition to the simple voltage level, an evaluation index such as a β value, an asymmetric value, a jitter value, or an error rate value known to those skilled in the art may be adopted as the signal state evaluation index.
The controlling circuit125uses the output from the characteristic value detection unit124, calculates the previously determined signal state evaluation index, and stores it in the memory127(step S87). The value of the signal state evaluation index calculated immediately after step S85is performed is treated as the reference value or the starting value of the signal state evaluation index.
Besides, measurement of an elapsed time or counting of a laser irradiation frequency is started from the execution of step S85.
The controlling circuit125determines whether the value of the signal state evaluation index reaches a target level (step S89). In the case of the signal state evaluation index which increases when the playback degradation advances, the target level is a level in which a specified rate a (for example, 5%) is added to the reference value of the signal state evaluation index. In the case of the signal state evaluation index which decreases when the playback degradation advances, the target level is a level in which the reference value of the signal state evaluation index is reduced by the specified rate α. That is, it is determined whether the playback degradation occurs and whether the state of the signal is changed from the reference value of the signal state evaluation index by the specified rate a or more.
When the value of the signal state evaluation index does not reach the target level, the controlling circuit125determines whether the elapsed time reaches a specified time or the laser irradiation frequency reaches a specified number of times (step S91). When the elapsed time does not reach the specified time or the laser irradiation frequency does not reach the specified number of times, return is made to step S87. On the other hand, when the elapsed time reaches the specified time or the laser irradiation frequency reaches the specified number of times, the playback degradation is low, and even if the specified time or the specified number of times is attained, the state of the signal does not change to the target level. In such a case, the laser irradiation is stopped and shift is made to step S93.
When the value of the signal state evaluation index reaches the target level, the controlling circuit125causes the LD driver121to end the laser irradiation. The controlling circuit125derives the playback durability index of the optical disk150(step S93). With respect to the playback durability index, the same way of thinking as that of the third embodiment is adopted. That is, there are properties that the value of the signal state evaluation index reaches the target level quickly when the playback degradation is high, and the value of the signal state evaluation index does not reach the target level quickly when the playback degradation is low. Thus, the degradation time as the time required to reach the target level or the deterioration frequency as the laser irradiation frequency required to reach the target level is adopted as the playback durability index.
However, when it is determined at step S91that the specified time or the specified number of times is attained, a value obtained by adding a suitable value (which may include 0) to the specified time or the specified number of times may be used as the degradation time or the deterioration frequency.
Thereafter, the controlling circuit125specifies the compensation amount of the playback condition corresponding to the derived playback durability index (step S95). For example, a correspondence table of a playback durability index and a compensation amount to be applied, or data of an expression to calculate a compensation amount to be applied from a playback durability index is stored in the memory127, and the compensation amount corresponding to the derived playback durability index is specified by using the correspondence table or the expression. Incidentally, the correspondence table or the expression may be recorded on the optical disk150, not the memory127, and may be read from the optical disk150. This process is the same as that of step S53of the third embodiment. That is, when the playback condition is the laser power level, the absolute value of the compensation amount is made to become large as the value of the playback durability index becomes small, and the compensation amount is made to approach 0 as the value of the playback durability index becomes large. When the playback condition is the rotational speed of the spindle motor133, the compensation amount of the rotational speed of the playback spindle becomes a large value as the playback durability index becomes a small value, and the compensation amount of the rotational speed of the playback spindle approaches 0 as the playback durability index increases.
The controlling circuit125sets the playback condition, in which the specified compensation amount of the playback condition is reflected, in the LD driver121or the servo controlling circuit132(step S97). That is, the compensation amount is added to the normal playback condition to specify the playback condition for subsequent data playback. When the laser power level is the playback condition, the playback condition is set in the LD driver121. When the rotational speed of the spindle motor133is the playback condition, the playback condition is set in the servo controlling circuit132.
The process as stated above may be performed before the data playback is performed, so that the playback degradation can be prevented or suppressed. That is, the playback durability for the data writable optical disk150can be ensured.
Other Embodiment
In the foregoing embodiments, the laser irradiation is continuously performed, the change of the playback signal is detected and the various processes are performed. However, the process may take a relatively long time. Then, values corresponding to the variability at step S7(first embodiment) or S29(second embodiment), the playback durability index at step S51(third embodiment) or step S93(fifth embodiment), and the variability of the signal state evaluation index at step S71(fourth embodiment) are stored in the memory127of the optical disk drive device100, and the values may be read and used. Besides, these values may be stored for each type of the optical disk150. Similarly, values on the optical disk150may be recorded of the optical disk150.
Further, the compensation amount itself of the playback condition or the playback condition itself after the compensation may be stored in the memory127or the optical disk150.
Besides, the rate for determining the target level, or the value of the specified time or the specified number of times may also be stored in the memory127or the optical disk150.
As described above, when data is held on the optical disk150, it may be held in a Lead-in area as shown inFIG. 14. The Lead-in area is roughly divided into a system Lead-in area, a connection area and a data Lead-in area. The system Lead-in area includes an initial zone, a buffer zone, a control data zone, and a buffer zone. The connection area includes a connection zone. Further, the data Lead-in area includes a guard track zone, a disk test zone, a drive test zone, a guard track zone, an RMD duplication zone, a recording management zone, an R-physical format information zone, and a reference code zone. In this embodiment, the control data zone of the system Lead-in area includes a recording condition data zone170. For example, the data as described above are held in the recording condition data zone170.
Although embodiments of the invention are described above, the invention is not limited to these. For example, the functional block diagram ofFIG. 1is for explaining the embodiments, and is not always coincident with the actual circuit and module constitution. Besides, with respect to the process flow, when the processing result is the same, the processing order may be exchanged, or the processing may be executed in parallel.
The structure and the operation of the present invention are not limited to the above descriptions. Various modifications may be made without departing from the spirit and scope of the present invention. While the above detailed description has shown, described, and pointed out novel features of the invention as applied to various embodiments, it will be understood that various omissions, substitutions, and changes in the form and details of the device or process illustrated may be made by those skilled in the art without departing from the spirit of the invention. The scope of the invention is indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
|
2QQMQÎ La présente invention est relative à un procédé eil *3 {^IQ^jafeil pour coucher des substances fluides sur des bandes de produits en mouvement et, plus particulièrement, à un procédé qui permet d'atteindre des vitesses de couchage maximales plus élevées que; celles obtenues jusqu'à ce jour, 5 On a décrit au brevet français 1 093•9^6 un procédé de couchage où une nappe de solution s'écoule d'une trémie, de manière continue, sur une bande en mouvement. Grâce à ce procédé,on peut augmenter considérablement ,;la vitesse de couchage et réduire l'épaisseur de la couche en appliquant sur les faces de la partie de la nappe comprise entre la trémie et la surface de la bar.de, partie 10 ci-après appelée ménisque, des pressions différentes. On exerce sur la face • de la nappe en regard de la bande une pression inférieure à celle qui s'exerce sur l'autre face de cette nappe. Suivant le brevet français 1 093 Ç66 on maintient- cette dépression au moyen d'une chambre disposée en regard de la face de la bande sur laquelle sera couchée la nappe. Cette dépression est comprise 15 entre 25 Fa et 1250 Fa, et elle est engendrée par un dispositif d'aspiration approprié. L'une des difficultés présentées par un tel procédé de couchage, particulièrement pour le couchage d'une bande de papier, réside en ce que le ménisque et la surface de la bande sont perturbés lorsqu'on atteint une certai— 20. ne vitesse de couchage critique. Cette vitesse de couchage est fonction d'un certain nombre de facteurs tels que la nature précise de la surface à coucher et les propriétés physiques et chimiques de la substance de couchage» Lorsqu'on atteint cette vitesse critique, le ménisque n'est pas" complètement rompu mais oscille plutôt, au hasard, provoquant des irrégularités dans la couche et 25 parfois emprisonnant des bulles d'air- dans celle-ci, On n'est pas sûr des causes exactes de cet effet mais un certain nombre de facteurs ont été déterminés et sont éliminés dans le procédé suivant la présente invention,1 La présente invention a pour objet un procédé de couchage permettant d'atteindre des vitesses de couchage maximales supérieures d'environ 50 ai ou 30 plus, à celles obtenues avec- le procédé de couchage classique, ce procédé pouvant être appliqué avec un appareil de couchage classique ayant subi de légères modifications peu coûteuses. L'invention a aussi pour objet roi .appareil:de couchage permettant d'atteindre des vitesses de couchage supérieures à celles obtenues jusqu'ici. 35 Le procédé d'application d'une couche de composition liquide sur une bande continue, suivant l'invention, dans lequel on maintient des pressions différentes sur les deux faces d'un ménisque formé par la composition liquide entre un dispositif d'application et la surface de la bande 'entraînée devant-ce dispositif sans contact avec celui—ci, la pression la plus faible s'exër— 40 ç.ar.t sur- la face du- ménisque qui vient, au contact de la bande, est -caractérisa 69 01280 2 2''00001 en ce qu'on soumet la face de la bande qui doit recevoir la couche à un dégazage en continu appliqué en amont du ménisque, dans la zone de plus faible pression, de manière à éliminer là couche d'air entraînée par la dite face de la bande. Suivant un mode de réalisation la pression de dégazage est inférieure 5 à la plus faible pression appliquée au ménisque et s'exerce sur toute la largeur de la bande. L'appareil de couchage, suivant la présente invention, comprend une surface support pour une bande de produit animée d'un mouvement continu, une trémie placée à une certaine distance de ce support et de la surface du pro— 10 duit sur laquelle elle débite, d'une manière continue, une nappe de composition liquide formant ainsi un ménisque, enamont de la trémie, une chambre de dépression dont l'ouverture est dirigée vers la face du ménisque venant au contact de la bande et recouvre une certaine longueur du produit à coucher au voisinage immédiat de ce ménisque, des moyens reliés à cette chambre pour abaisser la 15 pression s"exerçant sur cette face du ménisque par rapport à celle s'exerçant sur son autre face, cet appareil étant remarquable en ce qu'il comprend un dispositif d'aspiration supplémentaire logé dans cette chambre de dépression, pour éliminer, en amont du point de coucte.ge, la couche d'air entraînée par la face de la bande qui recevra la couche. 20 Au dessin annexé, donné seulement à titre d'.exemple : - la Pig. 1 est schéma de profil, avec coupe partielle, d'un mode de réalisation d'un appareil suivant l'invention ; — la Fig. 2 est une coupe partielle agrandie d'un ménisque, formé sur un appareil d'un autre type. 25 On a découvert que les vitesses de couchage critiques atteintes suivant les procédés classiques où un ménisque de substance de couchage est formé entre une trémie.et la surface d'une bande en mouvement et où on maintient des pressions différentes sur les faces opposées du ménisque peuvent être augmentées d'environ 50 ^ si la surface de la bande est soumise à une aspiration juste 30 avant le ménisque pour éliminer la couche d'air entraînée par cette bande. De préférence, cette aspiration devra être appliquée à l'intérieur de la chambre de dépression qui déjà réduit la pression sur la face du ménisque qui vient au contact de la bande. La Pig. 1 représente un appareil de couchage suivant la présente in-35 vention qui comprend un rouleau 10 supportant une bande W à coucher. Ce rour-leau est animé d'un mouvement de rotation continu par des moyens appropriés, non représentés, pour entraîner la bande dans le sens indiqué par les flèches dessinées le long de celle-ci. Une trémie 12, munie d'une fente verticale d'écoulement 13, transversale à la bande et dont la longueur est églae à la 40 largeur de cette dernière, est disposée à une certaine distance de la surface 69 01288 2000001 de la bande supportée par le rouleau 10. One pompe à débit constant, non représentée, débite dans une cavité 15 de la trémie une composition de couchage liquide L qui s'écoule à travers la fente 13 en une nappe S d'épaisseur pratiquement uniforme qui ensuite s'écoule par gravité sur un plan incliné 16. Tandis 5 que la nappe de liquide s'écoule par gravité le long du plan 16, son uniformité dans la direction "transversale s'améliore jusqu'à ce qu'elle forme un ménisque 18 franchissant l'espace compris entre une lèvre 19 de la trémie et la surface de la bande. Comme représenté à la Fig. 1, le ménisque 18 présente la forme d'une goutte ou d'un bourrelet qui s'étend sur toute la largeur de la bande. Ce 10 ménisque vient au contact de la bande qui se déplace pour entraîner par capillarité une couche C d'épaisseur uniforme d'une composition de couchage. On peut former initialement ce ménisque soit en pompant momentanément un excès de la composition de couchage dans la trémie, soit en amenant la trémie suffisamment près de la surface de la bande pour amorcer le ménisque puis en l'é— 15 loignant jusqu'à ce que le ménisque présente la forme désirée. Après avoir formé le ménisque de la composition de couchage, on règle le débit de la pompe de manière à ce que le débit compense la quantité de la composition de couchage entraînée par la bande. Afin d'éviter que le ménisque ne soit entraîné par la bande et ne soit 20 rompu, habituellement, comme décrit au brevet français 1 093 966, on réduit la pression sur la face du ménisque en regard de la bande non couchée. Pour cela, on dispose une chambre de dépression 20 en amont du point où se forme le ménisque. Cette chambre de dépression comprend une enceinte de forme générale pa— rallélépipédique ne comprenant pas de paroi sur sa face supérieure. On peut 25 fixer la chambre de dépression en un point 21 de la trémie et une partie d'une paroi 22 de la trémie à laquelle cette chambre est fixée peut former une partie" de la paroi arrière de l'enceinte. La paroi antérieure 23 de la chambre de dépression peut être écartée en 24 de la surface de la bande à coucher d'une faible distance par exemple 0,381 mm du côté de l'entrée. Ainsi le rouleau 30 support 10 et/ou la bande H supportée par celui—ci forme la paroi supérieure de la chambre de dépression. Cette chambre est reliée par un conduit 25 qui peut communiquer avec des moyens non représentés pour réduire la pression à l'intérieur de celle-ci. Le conduit 25 peut être muni d'une vanne V pour régler la pression dans la chambre 20. 35 Comme décrit au brevet français 1 093 9^6 on peut maintenir dans la chambre de dépression un vide partiel de 25 Pa à 1250 Pa en fonction de la vitesse de couchage et/ou de la viscosité de la composition de couchage pour éviter que le ménisque ne soit entraîné par la bande provoquant ainsi sa rupture. 40 Un appareil de couchage tel que décrit ci—dessus est bien connu et on 69 01208 2000001 a trouvé qu'il présentait certains avantages quant à l'accroissement de la vitesse de couchage et la réduction de l'épaisseur de la couche qui peut être appliquée sur une surface en mouvement. On a trouvé cependant que de tels appareils présentent une vitesse maximale critique au-dessus de laquelle le ménis-5 que 18 commence à osciller au hasard provoquant des irrégularités importantes dans le couchage et l'entraînement de bulles d'air dans la couche. A première vue, il semblait que l'on puisse éviter ces inconvénients en augmentant simplement l'aspiration dans la chambre de dépression. Quand on a essayé d'augmenter la dépression on a trouvé que ce n'était pas là le moyen d'éviter cet 10 inconvénient car le ménisque était aspiré dans la chambre de dépression provoquant sa rupture avant que n'apparaîsse un accroissement de la vitesse maximale critique de couchage. On a aussi découvert qu'il y avait une limite bien définie à la différence de pression que l'on peut appliquer sur les deux faces du ménisque sans entraîner l'aspiration de celui—ci dans la chambre de dépres— 15 sion et sa rupture. Suivant la présente invention on augmente la vitesse de couchage maximale critique de ce type d'appareil d'environ 50 $ en soumettant la surface de la bande légèrement en amont du point de couchage à une aspiration supérieure à celle exercée dans l'ensemble de la chambre de dépression. Ce but est at— 20 teint en munissant la chambre de dépression 20 d'un dispositif d'aspiration supplémentaire 30. Comme représenté, ce dispositif d'aspiration est formé par une fente étroite 31 adjacente de la bande et qui s'étend transversalement sur toute la largeur de la trémie. L'aspiration est appliquée à la fente 31 au moyen d'un collecteur approprié 33 efcd'une source d'aspiration distincte de cel-25 le produisant la dépression dans la chambre 20. Comme représenté à la Fig.1, un conduit 26 à la partie inférieure d'un collecteur 33 peut être connecté à une source d'aspiration, non représentée qui est indépendante de celle de la chambre 20. La fente 31 peut être distante de la surface de la bande W d'environ 0,762 nui et la paroi du collecteur traversée par cette fente présente 30 une surface concave concentrique au rouleau support de manière à assurer une action plus efficace de l'aspiration. A la Fig. 1 le dispositif d'aspiration est représenté comme étant monté à l'intérieur de la chambre de dépression 20 mais sa position par rapport au ménisque 18 n'est pas critique dans la mesure où ce dispositif est à l'in-35 térieur ou forme la paroi antérieure 23 de cette chambre, comme on l'a décrit ce dispositif d'aspiration doit couvrir la totalité de la largeur de la trémie même si seulement une partie de cette largeur est utilisée pour le couchage. EXEMPLE 1 - Suivant cet exemple le dispositif d'aspiration 30 est placé de manière à former la paroi antérieure 23 de la chambre de dépression 20 et la 40 fente 31 est disposée.à une distance de 0,508 mm de la bande W à coucher. La 69 01288 . -2000001 largeur de la fente elle-même est de 0,762 mm elle s'étend sur toute la largeur de la trémie 12 qui est de 3Ê,1 cm même si la bande à coucher occupe seulement 12,7 c"i au centre de la trémie. En conséquence, la distance séparant le dispositif d'aspiration du cylindre support est de 0,762 mm, l'épaisseur de 5 la bande étant de 0,254 mm. Pour le couchage d'une composition liquide consistant en une dispersion d'halogénures d'argent photosensibles dont la viscosité est de 10 mPl sur une bande de papier, la vitesse critique maximale est comprise entre 23,4«t 27,4 m/mn quand on utilise un dispositif de couchage usuel muni seulement d'une chambre de dépression, la vitesse critique d'un système usuel 10 muni d'un dispositif d'aspiration supplémentaire, suivant la présente invention, sera comprise entre 36,6 et 39»6 m/mn et le débit du dispositif d'aspiration est de 0,510 m^/mn et la pression dans le collecteur est de 5»48 kpa. EXEMPLE 2 — Pour cet exemple on utilise la même composition de couchage- et la même bande de papier, le dispositif d'aspiration étant distant de 0,762 mm du 15 papier (1,016 mm du cylindre support). Cette disposition entraîne une au g-mentation de la vitesse maximale critique du même ordre de grandeur que celle obtenue au premier exemple. EXEMPLE 3 - Suivant cet exemple, on porte la'largeur de la fente du dispositif d'aspiration à 1,27 mm ce qui entraîne une augmentation de la vitesse maximale 20 critique qui est alors comprise entre 45,7 m/mn et 48,8 m/mn. Bans ces conditions le débit du dispositif d'aspiration est de 0,623 m^/mn et la pression dans le collecteur est 4j23 kPa. On a découvert que l'efficacité du dispositif d'aspiration augmente avec la largeur de la fente en vertu, il faut croire, du débit de l'air. Cepen-25 dant, quand la largeur de la fente est supérieure à 1,27 mm l'efficacité du dispositif tombe d'une manière remarquable pour des raisons non encore connues. La distance séparant le dispositif d'aspiration de la bande peut varier entre 0,508 mm et 0,762 mm sans affecter les performances du système. Les distances au-delà de cette échelle n'ont pas été essayées. 30 II semble que le débit d'air soit le paramètre important puisque pour une certaine dimension de la fente la vitesse critique diminue quand on réduit le débit d'air. Le pourcentage d'accroissement de la vitesse critique et le débit d'air sont directement proportionnels dans l'intervalle de débits essayés jusqu'ici par exemple entre 0,283 et 0,623 m/mn. 35 Quand on transporte une bande de produit, il est bien connu qu'une couche d'air se déplace en même temps qu'elle et que la vitesse augmentant la quantité d'air entraînée augmente aussi. Le volume de cette couche d'air varie aussi en fonction des caractéristiques de la surface de la "bande à coucher, par exemple, elle augmente avec la rugosité de: la surface. Pour cette 40 raison une bande de papier entraînera, à une vitesse, donnée, une couche d'air 69 01288 2000001 plus épaisse que celle entraînée par un film de matière plastique à cause de la plus grande rugosité de sa surface. Il faut croire que cette couche d'air ' est dirigée vers le ménisque dans les dispositifs de couchage usuels et est augmentée par le courant d'air dans la région de basse pression juste avant le 5 point de couchage et que si la pression ainsi engendrée immédiatement en-dessous du ménisque est assez grande elle entraînera une instabilité de celui—ci. Le niveau exact de la pression, nécessaire pour provoquer l'instabilité du ménisque et qui augmentera avec la vitesse de couchage, dépendra d'un certain nombre de propriétés de la bande à coucher et de la composition de couchage, par 10 exemple, la rugosité de la surface de la bande, la viscosité de la substance de couchage, les caractéristiques de mouillabilité aussi bien de la surface de la bande que de celle de la composition de couchage, etc.. Le rôle du dispositif d'aspiration est d'éliminer, ou de limiter fortement, la couche d'air arrivant au point de couchage. Ceci réduit non seulement les possibilités 15 d'entraîner de l'air sous la couche mais de plus réduit le pression de l'air immédiatement avant le ménisque ou au point où le ménisque vient au contact avec la surface de la bande. En raison de sa disposition à prolimité de la surface de la bande, ce dispositif d'aspiration élimine principalement l'air entraîné par la bande et ne semble pas réduire d'une manière sensible la près— 20 sion dans la chambre de dépression. Toute tendance que peut présenter le dispositif d'aspiration à réduire la pression dans la chambre au point ou le ménisque pourrait être rompu peut être évitée en réglant la vanne V du circuit d'aspiration de la chambre pour maintenir une dépression voulue par exemple de 25 Pa à 1250 Pa. 25 Bien que la Pig. 1 représente une trémie du type qui débite d'une manière continue une nappe de substance de couchage pour former un ménisque en forme de bourrelet entre la trémie et la surface de la bande à coucher, la présente invention n'est pas limitée à l'utilisation d'un tel appareil de couchage. Par exemple, la trémie peut être du type à extrusion comme représenté à 30 la Pig. 1 du brevet français 1 093 966 et à la Pig. 2 de la présente demande où une nappe de substance de couchage L' est débitée sous pression à partir d'une fente de trémie 60 formée par deux lèvres 61, 62 d'une trémie placée à une certaine distance d'une bande W' animée d'un mouvement de translation par un rouleau support 10'. Dans ce cas, le ménisque compris entre la trémie et 35 la surface de la bande présente la forme d'un ruban 18' sur les faces opposées duquel on applique des pressions différentes au moyen d'une chambre de dépression 20'. En ce qui concerne la présente invention la forme du ménisque est peu importante pourvu qu'il soit continu. Donc dans toute la présente description et dans les revendications quand on se réfère à la masse de liquide com-40 prise entre la trémie.et la surface de la bande comme étant une nappe continue 69 01289 2 00001 une telle terminologie comprend une masse de liquide qtieile qu'en soit la forme par exemple tin bourrelet ou une goutte de substance comme représenté à la Pig. 1 ou un ruban de substance comme représenté à la Pig. 2, etc..
|
Stationary vibration isolation system and method for controlling a vibration isolation system
The invention relates to a stationary vibration isolation system and to a method for controlling such a system which comprises a damper effective in a horizontal direction which includes a fluid of variable viscosity.
CROSS-REFERENCE TO RELATED APPLICATIONS
European Patent Application No. 13 153 155.0, with a filing date of Jan. 29, 2013, is incorporated herein by reference.
FIELD OF THE INVENTION
The invention relates to a stationary vibration isolation system which is used in particular in semiconductor industry for accommodating lithography apparatus, and further relates to a method for controlling such a vibration isolation system.
BACKGROUND OF THE INVENTION
Stationary vibration isolation systems such as those used for mounting lithography apparatus are known in practice.
Such a vibration isolation system typically comprises mechanical or pneumatic springs on which a table or frame is mounted with vibration isolation, which table or frame serves to receive a lithography apparatus to be isolated.
Further, such vibration isolation systems are typically configured as so-called active vibration isolation systems in which sensors are provided at the anti-vibration mounted load and/or on the ground, which are configured as position-velocity sensors or acceleration sensors to measure vibrations, and the vibrations are actively counteracted using actuators. In particular Lorentz motors are used as the actuators.
A problem is that vibration isolation systems do not always only have the task to isolate the anti-vibration mounted load from vibrations from the environment, but that the anti-vibration mounted load likewise causes vibrations. In particular, photolithography steppers comprise a displaceable table which causes an acceleration of the anti-vibration mounted load in one direction or another when altering the direction or speed thereof.
Such vibrations caused by the anti-vibration mounted machine itself can be reduced by means of active vibration isolation using actuators, such as Lorentz motors.
A problem, however, is that there is a tendency of increasing the size of such lithography apparatus, which involves a correspondingly greater moving mass. Accordingly, the counteracting forces generated by the actuators have to be increased correspondingly, which makes the configuration of appropriate actuators more and more complex.
Published patent application EP 2 295 829 A1 (Integrated Dynamics Engineering GmbH) discloses a vibration isolation system in which, additionally, the pneumatic springs are used to provide counteracting forces.
However, pneumatic springs are only useful to provide counteracting forces in a vertical direction. Moreover, pneumatic springs which are controlled by means of valves exhibit a delayed response behavior, so that in case of very fast motions of the anti-vibration mounted load compensation is not sufficiently possible.
OBJECT OF THE INVENTION
Therefore, an object of the invention is to mitigate the drawbacks of the prior art.
More particularly, a vibration isolation system is to be provided, which enables to compensate in a simple manner for forces produced by motions of the anti-vibration mounted load, in particular by motions of a displaceable table. In particular, the need for ever increasing force actuators should be avoided.
SUMMARY OF THE INVENTION
The object of the invention is already achieved by a stationary vibration isolation system and a method for controlling a vibration isolation system according to any of the independent claims.
Preferred embodiments and modifications of the invention are set forth in the respective dependent claims.
The invention relates to a stationary vibration isolation system intended to accommodate machines in vibration-isolated manner, in particular lithography apparatus. The stationary vibration isolation system is in particular intended to receive photolithography steppers.
The system comprises a load that is anti-vibration mounted in both the horizontal and vertical directions. The load typically comprises a frame or table on which the lithography apparatus is arranged.
Furthermore, the anti-vibration mounted load comprises a moving mass. The moving mass in particular is a displaceable table such as those used in photolithography steppers.
Due to changes in motion of the moving mass such as alterations in speed and alterations of direction, a force is produced which may result in undesirable motions of the anti-vibration mounted load.
Typically, such a force mainly acts in a horizontal direction.
According to the invention, the anti-vibration mounted load is coupled to the base via a damper which is effective at least in horizontal direction, and which damper comprises a fluid of variable viscosity.
The base of a vibration isolation system typically defines a frame which rests on the ground. However, it is also conceivable to use the ground itself as a base of the vibration isolation system and to install springs and dampers directly on the ground.
The at least one damper couples the base with the anti-vibration mounted load and is able to absorb vibrations, at least temporarily.
The gist of the invention is to use a fluid of variable viscosity.
By using a fluid of variable viscosity, a mechanical coupling of the anti-vibration mounted load and the base may be induced temporarily. In this manner, in particular force impacts of displaceable tables can be diverted to the base.
The subject-matter of the invention benefits from the fact that the movements of steppers are usually quite rapid, whereas a vibration isolation system is especially intended to counteract slow movements, in particular of less than 100 Hz.
In case of such slow movements, the fluid of variable viscosity merely acts as a slightly viscous damping element.
Upon changes in motion of the anti-vibration mounted load, however, a very high damping effect is provided by virtue of an increasing viscosity, which damping is in particular at least ten times greater, and so the force is diverted to the base.
In this way, forces generated by motions of the anti-vibration mounted load can be offset at least partially by a frictional connection to the base.
The actively controlled force actuators, in particular Lorentz motors, which preferably continue to be provided, need no longer be adapted so that they are able to compensate for all the forces produced by the anti-vibration mounted load itself.
A non-Newtonian fluid may be used as the fluid of variable viscosity.
In a non-Newtonian fluid, the viscosity of the fluid increases with the shear rate.
Thus, the damping effect of the damper increases with the rapid movements of a displaceable table of a lithography stepper. This system may be employed as a purely passive system without electronic control.
Further, an electrorheological or magnetorheological fluid may be used as the fluid.
Electrorheological and magnetorheological fluids are materials in which the viscosity may be altered very quickly by an electric or magnetic field.
Such fluids are particularly known from active shock absorbers, such as those used in motor vehicles.
The use of an electrorheological or magnetorheological fluid allows the damper to be integrated into an active vibration isolation system.
It is in particular possible to provide an active control which detects the motion of the mass and based thereon controls the viscosity of the electrorheological or magnetorheological fluid.
In particular so-called feed-forward control may be provided, in which the motion of the anti-vibration mounted mass, in particular the motion of a displaceable table, is not only detected passively using a sensor, but in which the known motion pattern of the table is used to generate compensation signals so to speak in advance.
In one modification of the invention, the anti-vibration mounted load is additionally coupled to the base in the vertical direction via a damper which comprises a fluid of variable viscosity.
In this way, vertical force components may also be compensated for.
In one embodiment of the invention, the fluid of variable viscosity is arranged in a vibration isolator.
In particular it is possible to use a vibration isolator configured as a pneumatic spring, in which the piston has an extension which is immersed in a chamber containing the fluid of variable viscosity.
An advantage of this embodiment of the invention is that all components of the damper may be incorporated in the isolators.
In an alternative embodiment of the invention, the damper is configured as an external component, which in particular provides for retrofitability of a conventional vibration isolation system in a simple manner.
The invention further relates to a method for controlling a vibration isolation system that comprises a lithography apparatus including a moving mass.
Based on the movement of the mass, a damper which is effective at least in a horizontal direction and which comprises an electrorheological or magnetorheological fluid is controlled so that the damping effect increases upon a change in motion of the mass, i.e. in the event of an acceleration applied on the system by the mass.
The change in motion of the mass may be detected by a sensor.
Preferably in this case, known motion information, in particular that of a displaceable table, is accounted for in controlling the damper.
Preferably, at least one sensor detects vibrations of the anti-vibration mounted load and/or of the ground, and based thereon actuators are controlled for active vibration isolation, in particular Lorentz motors.
In one modification of the invention, both the vibration of the ground or of the lithography apparatus detected by the sensors and the detected motion of the mass are considered in calculating a signal for controlling the actuator.
The motion of the mass, in particular of the displaceable table, is not only used for controlling the damper in feed-forward control, but also for controlling the actuator.
DETAILED DESCRIPTION
The subject matter of the invention will now be explained in more detail with reference to the drawings ofFIGS. 1 to 6by way of schematically illustrated exemplary embodiments.
In this vibration isolation system, the ground4is used as a base for receiving an anti-vibration mounted load2. The anti-vibration mounted load2is coupled with the ground4via vibration isolators3which are typically configured as a pneumatic spring.
Furthermore, the vibration isolation system comprises sensors. In this exemplary embodiment, sensor5is provided as a position sensor, sensor6as a speed or acceleration sensor of the anti-vibration mounted load2in the vertical direction, and sensor7as a sensor effective in the horizontal direction.
By virtue of sensors5,6,7it is possible to use compensating signals to control an actuator23, by means of a control device (not shown).
In this exemplary embodiment, actuator23is integrated in vibration isolator3. In particular a Lorentz motor is used as the actuator.
Actuator23is effective both in the horizontal and vertical directions in this exemplary embodiment.
The anti-vibration mounted load2comprises a lithography apparatus1which in this exemplary embodiment is configured as a displaceable table of a stepper that changes its direction of movement8. Due to the acceleration caused thereby, forces are applied to the anti-vibration mounted load2.
The vibrations or motions of the anti-vibration mounted load2in form of a table together with components placed thereon may be counteracted by controlling actuator23. However, with increasing size of the lithography apparatus1, bigger and bigger actuators are required.
Therefore, according to the invention, the anti-vibration mounted load2may be coupled with the base or ground4via dampers9, as shown inFIG. 2.
Dampers9comprise a fluid of variable viscosity (not shown), so that the damping effect is variable.
Forces applied by the lithography apparatus1as a result of a motion of the displaceable table may now be diverted to the ground4, due to a frictional connection via dampers9, so that the requirements on the actuators of the system are reduced.
FIG. 3schematically illustrates a vibration isolator3in which the fluid of the damper is integrated in the vibration isolator3.
Vibration isolator3is configured as a pneumatic spring and includes a working space13.
A preferably controllable valve14may be used to control the pressure in the working space13.
Vibration isolator3further comprises a piston11on which the anti-vibration mounted load rests.
Working space13is sealed on the piston side by a membrane12which is secured on the housing of working space13by means of a clamping ring10.
Above membrane12, a seal15is arranged which enables to introduce a fluid between membrane12and seal15, in particular a liquid of variable viscosity.
Fluid16may be a non-Newtonian fluid, for passively changing the damping effect, or an electrorheological or magnetorheological fluid, for actively changing the damping effect.
If now, due to a change of motion of a displaceable table, a force, in particular a horizontal force, is applied to the piston11which is rigidly connected to the anti-vibration mounted load, the viscosity of fluid16can be increased, whereby a frictional connection is established between piston11and clamping ring10.
At least horizontal force components may be diverted to the base in this manner, at least partially.
FIG. 4shows another schematic view, in which the illustrated vibration isolator substantially corresponds to the vibration isolator shown inFIG. 3, being configured as a pneumatic spring including a working space13.
A fluid16of variable viscosity is arranged between piston11and clamping ring10. In this exemplary embodiment, the fluid is an electrorheological fluid16.
When installed in a vibration isolation system, isolator3is controlled by a control device21. Control device21is connected to the lithography apparatus1. Changes in the direction of movement8of the displaceable table are communicated from lithography apparatus1to control device21. Based on this change of motion, the control device determines the force generated by lithography apparatus1and based thereon controls the power source22by means of which the viscosity of fluid16is controlled.
Thus, the vibration isolation system comprises a feed-forward control which in the event of forces caused by the lithography apparatus, preliminarily achieves a frictional connection between the anti-vibration mounted load and the base.
It will be understood that control device21moreover may be part of an active control and may additionally control actuators for active vibration isolation (23inFIG. 1).
FIG. 5shows another exemplary embodiment of a vibration isolator3which is likewise configured as a pneumatic spring including a working space13.
This vibration isolator3likewise comprises a piston11.
Working space13is sealed by a membrane12, which is secured on the housing of the working space by means of clamping ring10.
In this exemplary embodiment, piston11has an extension18which projects into the working space13of the isolator.
Within working space13, a chamber17is provided which is filled with a fluid16of variable viscosity.
If the fluid is an electrorheological fluid, the viscosity of the fluid16may be controlled by applying a voltage between the wall of chamber17and extension18.
FIG. 6shows a sectional view of a practical vibration isolator3.
It comprises working space13.
Piston11is movable relative to the working space both in the horizontal and vertical directions and may be fixed to the anti-vibration mounted load by means of fastening element19.
Furthermore, clamping ring10can be seen, by means of which the working space is sealed using a membrane.
The piston now comprises extension18which projects into the preferably sealed chamber17which is arranged within the working space and which comprises a fluid16of variable viscosity.
Vibration isolator3further comprises a foot20by means of which it may be fixed on the ground or on a base.
By increasing the viscosity of fluid16, a frictional connection may be achieved between piston11and the housing of working space13and thus ultimately between the anti-vibration mounted load and the base.
The invention permits in a very simple manner to divert forces which are caused by an anti-vibration mounted load, in particular by a stepper, to the ground, at least partially, so that they do not need to be completely counteracted by actuators.
LIST OF REFERENCE NUMERALS
|
Les vannes à papillon ont des avantages reconnaQX ité et de facilité de commande, ce dernier résultant de l'équilibrage des poussées axiales des fluides à obturer. Toutefois un inconvénient majeur de ces vannes est celui de ne pas se prêter à la réalisation dlune obturation parfaite du fluide commandé, dans les cas où cette étanchéité est nécessaire. La présente invention remédie à cet inconvénient en réunissant, dans un mouvement de commande unique, deux temps successifs 10----- manoeuvre de fermeture progressive du papillon, jusqu'à sa position perpendiculaire à l'axe de la conduite 2"----- déplacement du papillon (parallèlement à lui-même) jusqu'à son application sur un siège circulaire ce second temps pouvant utilement se décomposer en deux périodes~: a/-- rapprochement du papillon contre une butée circulaire, et b/-- continuation du même mouvement provoquant la compression d'un joint périphérique; ces temps ou périodes se répétant en sens inverse lors de l'ouverture de la vanne Les figures annexées montrent à titre d'exemple non limitatif une forme de réalisation préférée de l'invention (fig.l à 6 avec papillon à siège; et fig.7 à 9 avec joint pariphérique). La fig.1 montre une élévation-coupe de la commande, en position fermée; Lafig.2montre une coupe selon 2-2 de la fiig.1 La fig.3 montre une coupe selon 3-3 de la fig.1 La fig.4 est une coupe de la vanne, en plan, en position ouverte. La fig.5 est une eue à plus grande échelle du déverrouillage automatique de la commande rotative du papillon en fin du ler temps; La fig.6 montre le détail de commande du déplacement parallèle du papillon à partir du commencement du 2e temps; La fig.7 montre à très grande échelle le joint périphérique et sa position au début du 2e temps; La fig.8 le montre de même à la fin de la période a/ du 2e temps; La fig.9 le montre enfin à la fin de la période b/ du 2e temps. Sur ces figures les mêmes références désignent les mêmes organes 10 est le corps de vanne, comportant des brides lOt pour son raccordement aux tuyauteries, il est ltarbre de commande, 12 est le papillon, qui est accouplé en rotation à l'arbre 11 par un verrou à bascule 13 dont le ressort 13t sollicite le bec 13" à pénétrer dans la rainure 11' de 11 ( fig.2 et et 5 ). L'arbre 11 torte deux parties excentrées 14 tournant dans des coussinets 15 (fiv6) dont les faces externes peuvent coulisser entre le papillon 12 et des guides 16 vissés sur lui, mais maintenue à distance convenable par des entretoises 1? ; ces dernières maintenant l'arbre 11 dans le centre de 12 par des facettes 17'. D'autre part l'alésage du corps 10, généralement cylindrique, est usiné dans la zone de fermeture du papillon 12 en une forme sensiblement sphérique (rayon R, fig.3) et I'extérieur du papillon lui-même est usiné dans la forme sensiblement correspondante. Si lton désire que le 2e temps soit réalisé en deux périodes, le papillon est équipé dlun joint périphérique 18 susceptible d'être comprimé entre un redan 12' de 12 et la bague coulissante 19 disposée pour être la premiere å venir en contact avec le corps 10 lors de la poussée de 12 dans le sens de son écartement de l'arbre 11. Fonctionnement On conçoit aisément qu'ainsi disposée la commande en rotation de l'arbre 11 en sens A(fig.4 & 5) entraînera le papillon 12 de sa position ouverte (fig.4) à sa position perpendiculaire (fig.3) mais que dans la fin de cette course rotative de 900 le verrou 13 butera sur le talonlO" solidaire de 10 (fig.5), et qu'à partir de ce moment, la cannelure 11' étant désaccouplée de 13", l"arbre 11 continuera sa rotation en sens A et,par les deux excentriques 14, éloignera le papillon 12 de l'arbre 11, en réalisant successivement ---- soit l'application directe de la périphérie de 12 contre 10 (par progres sion en sens F, fiv.5); ; ---- soit ce mouvement en deux périodes, par a/-- application de la bague 19 et du joint 18 contre lO(fig.7 à 8); puis b/-- compression du joint 18 entre 19 et 12' (fig 8à9) et son "fluage" radial entre 12' et 10, assurant une étanchéité cl'autant plus accentuée que l'action en rotation sur l'arbre 11 aura été plus énergique. Bien entendu la forme de réalisation ci-dessus décrite et représentée ne l'est qu'à titre d'exemple et peut varier dans une large mesure sans porter atteinte aux caractéristiques de llinvention, revendiquées ci-après. REVENDICATIONS 1.---- Commande de vanne à papillon par arbre en rotation dans un même sens, en deux temps successifs 1" manoeuvre de fermeture progressive du papillon, jusqu'à sa position perpendiculaire à l'axe de la conduite 2" déplacement du papillon (parallèlement à lui-même) jusqu'à son application sur un siège circulaire, lors ces temps se répétant en sens inverse due l'ouverture de la vanne 2---- Commande selon revendication 1, dans laquelle le deuxième temps énoncé est décomposé en deux périodes successives a/-- rapprochement du papillin contre une butée circulaire; et b/--- continuation du même mouvement provoquant la compression dlun joint périphérique; ces périodes ye répétant en sens inverse lors de ltouverture de la vanne
|
Method for operating a metering unit of a catalytic converter
In order to ensure optimum metering of a reagent to be metered into an exhaust gas during operation of a metering unit of a catalytic converter of a combustion system, in particular an internal combustion engine of a motor vehicle, in any operating state of the catalytic converter and/or in any operating state of the combustion system, a method and a device for operating a metering unit of a catalytic converter of a combustion system provide that, based on a steady-state value of the reagent quantity to be metered during a steady-state operating state of the catalytic converter and/or the combustion system, the quantity of the at least one reagent is determined and adjusted using at least one dynamic correction factor which is dependent on at least one of the performance characteristics of the catalytic converter and on at least one of the performance characteristics of the combustion system. The dynamic correction factor and/or a nitrogen oxide correction factor are obtained from a dynamic correction characteristics map or a nitrogen oxide correction characteristics map only as a function of performance characteristics of the internal combustion engine, in particular the engine speed and the injected fuel quantity, and of performance characteristics of the catalytic converter, preferably the nitrogen oxide emission and the temperature of the exhaust gas downstream from the catalytic converter.
BACKGROUND INFORMATION
To reduce the emission of pollutants, in particular the emission of nitrogen oxides during the operation of combustion systems, exhaust systems of internal combustion engines in motor vehicles are equipped with catalytic converters. Using these, most of the hydrocarbons and carbon monoxide contained in the exhaust gas are burned. However, a large portion of harmful nitrogen oxides, which are discharged into the environment, remains in the exhaust gas when conventional catalytic converters are used.
The nitrogen oxide content in the exhaust gases can also be reduced by using reduction-type catalytic converters. Reduction of nitrogen oxides by adding reduction agents to an exhaust gas flow, also known as selective catalytical reduction (SCR), is known from European Patent Application No. EP 1 024 254.
The reduction agent quantity is determined here based on a load variable, e.g., injected fuel quantity and/or the engine speed, and at least one performance characteristic, e.g., the exhaust gas temperature upstream from the catalytic converter. Moreover, by using at least one characteristics map, the reduction agent quantity is adjusted as a function of at least one additional performance characteristic, e.g., the exhaust gas temperature downstream from the catalytic converter.
For this purpose, a temperature difference is formed between the actual temperature and the setpoint temperature of the exhaust gas downstream from the catalytic converter. Different characteristics maps, in which an adjusted reduction agent quantity is stored as a function of the engine speed and the injected fuel quantity, are provided for different temperature differences.
In order to take into account all occurring temperature differences as completely as possible and to achieve optimum adjustment, as many characteristics maps as possible are used, so that the reduction agent quantity can be accurately determined. Maximum nitrogen oxide conversion and minimum emission of unconverted reduction agent (reduction agent slip) is to be ensured in each operating state of the internal combustion engine and/or the catalytic converter, in particular at different temperatures, different injected fuel quantities, and/or different engine speeds. Prior to the initial startup of the engine and/or the catalytic converter, the characteristics maps must be recorded (calibrated) in advance, by the manufacturer, for example. The more characteristics maps are used, the greater is the metering accuracy during each operating state of the catalytic converter and/or each operating state of the combustion system, but also the greater is the calibration complexity and the more complex is the assignment of the characteristics maps.
SUMMARY OF THE INVENTION
The present invention is based on the technical problem of improving a method and a device for operating a metering unit of a catalytic converter of a combustion system, in particular an SCR catalytic converter of an internal combustion engine in a motor vehicle, e.g., a utility vehicle, in such a way that metering of the quantity of reagent to be metered, in particular of a reduction agent such as a urea/water solution, takes place by requiring little calibration complexity based on as few as possible characteristics maps and still achieving an optimum pollutant reduction and that, in particular, the amount of nitrogen oxides in the exhaust gas is reduced in such a way that specified limiting values are not exceeded.
It is essential, in particular in view of the use of internal combustion engines in motor vehicles in different countries having different emission guidelines, to provide a number of different catalytic converters which meet the particular emission guidelines and which, in case of need, are quickly exchangeable. This requires in particular a marked reduction in the calibration complexity.
In the method according to the present invention, a steady-state value of a reagent quantity to be metered (steady-state reagent value) is determined based on an assumed steady-state operating state of the catalytic converter and/or the combustion system, characterized by the current performance characteristics, independent of the performance characteristics of the catalytic converter, the steady-state value being adjusted using at least one dynamic correction factor (dynamic correction). As a function of at least one of the performance characteristics of the catalytic converter and at least one of the performance characteristics of the combustion system, the dynamic correction factor is obtained from a dynamic correction characteristics map.
In terms of the present invention, steady-state means that constant (steady-state) operating states of the catalytic converter and/or the combustion system over a longer period of time are assumed, e.g., operating states predetermined by the manufacturer. Therefore, steady-state values correspond to values of the particular variables during steady-state operating states, e.g., characterized by a constant nitrogen oxide emission and a constant exhaust gas temperature downstream from the catalytic converter. The steady-state reagent value is dynamically adjusted to changes, in the exhaust gas temperature for example, via the dynamic correction. In other words, the dynamic correction takes into account that, during operation of the combustion system and the catalytic converter, indeed no steady-state but rather dynamic operating states prevail during the actual operating situation.
It is an advantage here that not only operation-relevant parameters of the combustion system and the catalytic converter, the exhaust gas in particular, are used, but also steady-state values, preferably stored in characteristics maps, in which constant (steady-state) operating states of the catalytic converter and/or the combustion system are assumed.
Only one additional characteristics map (exhaust gas temperature characteristics map) for the steady-state value of the exhaust gas (steady-state exhaust gas temperature value), which is separately calibratable for each catalytic converter by the manufacturer, and the determination of the actual exhaust gas temperature downstream from the catalytic converter, with which the steady-state exhaust gas temperature value is adjusted, are necessary. Thus, using only three variables to be measured, namely the exhaust gas temperature value downstream from the catalytic converter, a value for the engine speed, and a value for the injected fuel quantity and only three corresponding characteristics maps, namely the dynamic correction characteristics map, the exhaust gas temperature characteristics map, and a characteristics map for the steady-state reagent value (reagent characteristics map), the necessary reagent quantity is accurately determinable.
In a preferred embodiment of the method, the steady-state reagent value is additionally adjusted using a nitrogen oxide correction factor as a measure for the deviations between a steady-state value for a nitrogen oxide emission (steady-state nitrogen oxide value) from a nitrogen oxide characteristics map and the present nitrogen oxide emission value, preferably by multiplication. The steady-state nitrogen oxide value is stored in the nitrogen oxide characteristics map as a function of the value for the engine speed and the value for the injected fuel quantity. This has the considerable advantage that erroneous metering due to fluctuations in the nitrogen oxide emission, which may take place statically, as well as dynamically, is drastically reduced. Erroneous metering may occur when the determination of the steady-state reagent value was based on a constant, steady-state nitrogen oxide emission. The adjustment to the actual situation in which the nitrogen oxide emission changes dynamically takes place due to the fact that the quantity of the at least one reagent is determined from the steady-state reagent value via correction using the deviation from the actual amount of nitrogen oxide.
It is an additional advantage that only the value of the nitrogen oxide emission is necessary, which is advantageously determined using a nitrogen oxide sensor or via simulation of engine data, measured values, and/or characteristic maps by computing differential equations and/or functionals. The nitrogen oxide emission value is accurately detectable using the nitrogen oxide sensor, whereas the simulation of the nitrogen oxide emission value has the advantage that no nitrogen oxide sensor is necessary, since variables which are detected anyway are used, preferably the values for engine speed and the injected fuel quantity.
A further advantageous embodiment of the method provides the adjustment of the quantity of the at least one reagent using a value of the operating time of the catalytic converter, a value of the operating time of the combustion system, a value of the ambient temperature, a value of the coolant temperature of the combustion system and/or a value of the air moisture, e.g., via multiplication with a corresponding factor. This has the advantage that metering is adjusted to changing environmental influences, whereby the metering accuracy is markedly improved.
In the device according to the present invention at least one means for determining the steady-state reagent value, one correction means for executing the dynamic correction, one dynamic correction characteristics map in which at least one dynamic correction factor is stored, and detection means for detecting at least one of the performance characteristics of the catalytic converter, and at least one of the performance characteristics of the combustion system are provided, with which an adjustment of the steady-state output variables to dynamically changing operating conditions may take place in a simple manner and without great technical complexity.
The difference between the steady-state exhaust gas temperature as a performance characteristic and the exhaust gas temperature downstream from the catalytic converter as another performance characteristic is preferably stored in the dynamic correction characteristics map, making quick access to these performance characteristics possible.
In addition, an advantageous embodiment provides for a control unit having a dynamic correction characteristics map and/or a nitrogen oxide characteristics map. It is an advantage here that, without great technical complexity, the characteristics maps for the dynamic correction are storable in a single control unit, e.g., by programming, and are quickly accessible.
A further advantageous embodiment provides a nitrogen oxide sensor for determining the nitrogen oxide emission value and/or a processor unit for simulating the nitrogen oxide emission value from engine data, measured values and/or characteristics maps via computation, e.g., based upon differential equations and/or functionals. It is possible to determine the nitrogen oxide emission value simply and quickly by using the nitrogen oxide sensor, whereas in the simulation an additional sensor may be omitted altogether.
DETAILED DESCRIPTION
The method and the device according to the present invention are explained below in connection with a metering unit50, illustrated inFIG. 1, of an SCR catalytic converter10of a controlled diesel catalytic converter (cd-modulcat) of an internal combustion engine3in the form of a diesel engine of a commercial motor vehicle for metering a urea/water solution (UWS)200as a reduction agent into exhaust gases for selective catalytic reduction of nitrogen oxides in particular. However, the method and the device are not limited to metering unit50of the SCR catalytic converter10or to the use in a utility vehicle or any other motor vehicle having a diesel engine. Instead, they are useable anywhere where exhaust gases of a combustion system, e.g., an oil heating system or a gasoline engine, are to be purified. Instead of the cd-modulcat, any other catalytic converter, of a direct-injection gasoline engine for example, may be provided. In addition, the method and the device are not limited to metering UWS200, in fact, also other and multiple different liquid and/or gaseous reagents, also as a mixture, may be metered. Instead of being metered into exhaust gases, UWS200may also be metered into other liquid and/or gaseous fluids.
SCR catalytic converter10is connected to engine3via an exhaust pipe20. During the operation of engine3, untreated exhaust gas of engine3is supplied to SCR catalytic converter10in a direction (flow direction) indicated by an arrow25. The exhaust gas is purified in SCR catalytic converter10in a manner known per se. Purified exhaust gas is discharged into the environment downstream from SCR catalytic converter10via an exhaust tract30(Arrow35).
Using metering unit50, UWS200is supplied to exhaust pipe20via a metering line40to reduce the nitrogen oxides contained in the untreated exhaust gas in a manner known per se.
UWS200in turn is supplied to metering unit50from a container206via a UWS feed line205. In principle, metering unit50may also be connected to a different device for supplying UWS200.
Using a control unit90, metering unit50is controllable via a control line110. Quantity400of UWS200, determinable as a function of the performance characteristics of SCR catalytic converter10and engine3, is determinable, preferably computable, using control unit90, as described in connection withFIG. 2.
A value for the exhaust gas temperature TCat,nof the purified exhaust gas is detectable as a performance characteristic of SCR catalytic converter10using a temperature sensor160in exhaust tract30and is transmittable to control unit90via a temperature signal line165. A value for engine speed n as a first performance characteristic of engine3is detectable using an engine speed sensor140of engine3and is transmittable to control unit90via an engine speed signal line145. Likewise, a value for injected fuel quantity ME as a second performance characteristic of engine3is detectable using a fuel measuring device142of engine3and is transmittable to control unit90via an injection signal line147.
In principle, injected fuel quantity ME may be obtained from a characteristics map in a known manner based on a load signal from an accelerator pedal path, so that fuel measuring device142may be omitted.
In principle, other performance characteristics characterizing engine3and/or SCR catalytic converter10, which are detectable using appropriate detecting means, may alternatively or additionally be used.
In a first exemplary embodiment of the method according to the present invention, illustrated inFIG. 2, the detected values for engine speed n and injected fuel quantity ME are transmitted to a first steady-state characteristics map (exhaust gas temperature characteristics map)300in which a steady-state value of the exhaust gas temperature downstream from SCR catalytic converter10is stored as a function of the values for engine speed n and injected fuel quantity ME.
In terms of the present invention, steady-state means that constant (steady-state) operating states of SCR catalytic converter10and engine3are assumed, e.g., operating states predetermined by the manufacturer. Therefore, steady-state values correspond to values of the particular variables during steady-state operating states, e.g., characterized by a constant nitrogen oxide emission and a constant exhaust gas temperature downstream from SCR catalytic converter10.
Steady-state characteristics maps are determined, e.g., by the manufacturer, via measurements on an engine test bench in steady-state operating states of engine3and SCR catalytic converter10.
In addition, a steady-state value for the UWS quantity to be metered (UWS steady-state value320) is determined from a second steady-state characteristics map (UWS characteristics map310) as a function of the values for engine speed n and injected fuel quantity ME. Moreover, UWS steady-state value320may be picked up at an interface Ext and may, in principle, be transmitted to a processor unit or an output unit (not shown). But interface Ext may also be omitted.
UWS characteristics map310is determined, e.g., by the manufacturer, using a variation of UWS metering during steady-state operation of engine3and a defined UWS slip. UWS steady-state value320corresponds to the UWS quantity to be expected during a steady-state operating state of catalytic converter10, characterized, for example, by a steady-state exhaust gas temperature.
UWS steady-state value320is calibrated during a steady-state operating state at a predetermined, tolerable UWS slip.
A dynamic correction factor380is determined from exhaust gas setpoint temperature value305and the difference360between exhaust gas setpoint temperature value305and exhaust gas temperature value TCat,nfrom an additional characteristics map (dynamic correction characteristics map370). Difference360is computed using a subtractor350. Using the dynamic correction value, UWS steady-state value320is adapted to the actually prevailing operating states which change dynamically and which are characterized, for example, by changes in the nitrogen oxide emission during the operation of engine3, in the possible conversion rate of UWS200as a function of a catalytic converter temperature and/or in the amount of UWS200stored in catalytic converter10.
Dynamic correction characteristics map370is also determined on an engine test bench, e.g., by the manufacturer.
UWS steady-state value320is dynamically adapted to changes, in the exhaust gas temperature for example, using the dynamic correction. In other words, the dynamic correction takes into account that, during operation of engine3and SCR catalytic converter10, actually no steady-state but rather dynamic operating states prevail during the actual operating situation.
The same reference numbers identify the elements of the second exemplary embodiment of the method according to the present invention illustrated inFIG. 3which are identical to those of the first exemplary embodiment described inFIG. 2, so that, with regard to their description, full reference is made to the first exemplary embodiment.
This second exemplary embodiment differs from the first exemplary embodiment illustrated inFIG. 2in that, subsequent to the dynamic correction, quantity400of UWS200is multiplied by a deviation factor590of the nitrogen oxide emission using an additional multiplier600. Deviation factor590is computed by dividing a filtered nitrogen oxide emission value560by a likewise filtered steady-state value of the nitrogen oxide emission (filtered steady-state nitrogen oxide value570) using a quotient generator580.
Filtered nitrogen oxide emission value560is determined from a nitrogen oxide emission value505using a first filter F1. In turn, nitrogen oxide emission value505is detected upstream from SCR catalytic converter10using a nitrogen oxide sensor, for example (not shown).
In principle, instead of using the nitrogen oxide sensor, nitrogen oxide emission value505may also be simulated from a model (not shown) via computing differential equations and/or functionals based on engine data, measured values, and/or characteristics maps.
Filtered steady-state nitrogen oxide value570is determined from a steady-state value of the nitrogen oxide emission (steady-state nitrogen oxide value550) via filtering using a second filter F2.
In principle, filter F1and filter F2may be dispensed with, which then may result in value fluctuations caused, for example, by electromagnetic interference signals.
Filtered steady-state nitrogen oxide value570and steady-state nitrogen oxide value550correspond to the nitrogen oxide emission to be expected during a constant (steady-state) operating state of SCR catalytic converter10, in particular at a constant exhaust gas temperature.
Steady-state nitrogen oxide value550is obtained from a fourth steady-state characteristics map (nitrogen oxide characteristics map520) as a function of the values for injected fuel quantity ME and engine speed n.
Nitrogen oxide characteristics map520is determined on an engine test bench during a steady-state operating state of SCR catalytic converter10, e.g., by the manufacturer.
The four characteristics maps or steady-state characteristics maps300,310,370, and520, described in connection withFIGS. 2 and 3, may, in principle, be stored in control unit90and may, in a manner known per se, be imported or changed via data transmission or software-related programming. They may, however, also be stored at a different location, in an engine control unit, for example.
In principle, the values for engine speed n and/or injected fuel quantity ME may also be transmitted via a bus system, e.g., a controller area network (CAN). Instead of or in addition to the values of engine speed n and injected fuel quantity ME, other performance characteristics of engine3may also be used.
As described in connection withFIG. 2, instead of basing dynamic correction factor380on exhaust gas temperature value TCat,nand exhaust gas setpoint temperature value305, it may also be obtained from dynamic correction characteristics map370based on nitrogen oxide emission value505and steady-state nitrogen oxide value550or another performance characteristic of SCR catalytic converter10, the dynamic correction characteristics map370being appropriately calibrated beforehand. Deviation factor590, described in connection withFIG. 2, may then be obtained, as a function of exhaust gas temperature value TCat,nand exhaust gas setpoint temperature value305, from an appropriate characteristics map which is also calibrated beforehand. Instead of exhaust gas temperature value TCat,n, other performance characteristics of SCR catalytic converter10may be used here.
|
Les colonnes de vide-ordures situées dans les immeubles modernes représentent autant de foyers permanents d'infection si elles ne sont pas périodiquement nettoyées et désinfectées. Le nettoyage proprement dit de ces colonnes suppose la mise en oeuvre de moyens à caractère mécanique ou physique relativement importants, et qui ne peuvent par conséquent pas être mis en jeu avec une fréquence très éleve.- Par ailleurs, les règlements d'hygiène, tenant compte de l'impossibilité sur le plan économique d'imposer de tels nettoyages à une fréquence très élevée, en limitent la cadence à un minimum d'une intervention annuelle. Il est bien évident qu'unie telle fréquence est insuffisante pour éliminer les risques dtinfection et de propagation d'infection par l'intercommunication qui s t établit d'étage en étage, et d'appartement à appartement par le moyen des colonnes de vide-ordures, sans qui il soit d'ailleurs possible de prévoir un équipement de saosbu dtobturateurs,suffisamment étanches pour éliminer le risque de propagation des foyers microbiens. I1 apparaît donc nécessaire d'effectuer des opérations de désinfection des colonnes, sinon continues, du moins avec une fréquence suffisamment élevée pour que tout risque de développement d'un foyer d'infection soit pratiquement éliminé. Ceci suppose une cadence d'intervention qui dépend évidemment de la température ambiante régnant dans la colonne, aussi bien que du nombre de foyers branchés sur- la colonne, mais en tout état de cause, la fréquence nécessaire pour obtenir une sérilisation satisfaisante des éventuels foyers d'infection est telle qu'il ne peut être envisagé d'intervenir avec les moyens habituels et qu'il est nécessaire de prévoir un dispositif permanent pouvant être mis en action quotidiennement ou même plusieurs fois par jour par le responsable du gardiennage de l'immeuble au moyen d'une manoeuvre simple, voire automatiquement suivant un horaire prédéterminé. A cet effet, le dispositif de désinfection de colonne de vide-ordures selon l'invention est essentiellement caractérisé en ce qu'il comprend des injecteurs de liquide désinfectant étagés le long de la colonne et reliés par une canalisation à une source de délivrance du liquide désinfectant sous pression, per mettant une désinfection semi-continue de la colonne. Une forme de réalisation de l'invention est ci-après décrite, à titre d'exemple, et en référence au dessin annexé, dont la figure unique est une vue schématique d'un tel dispositif de désinfection. Au dessin, la colonne de vide-ordures est figurée en 1 et les vide-ordures d'étage en 2. Le dispositif de désinfection comprend plumeurs injecteurs 3 régulièrement etagés le long de la colonne, et débouchant dans celle-ci en vue d'y diffuser de manière convenablement répartie un liquide désinfectant qui leur est amené par une canalisation 4 latérale à la colonne de videordures. Cette canalisation 4, destinée à être alimentée sous pression en liquide désinfectant, est ici reliée à cet effet au refoulement d'une pompe 5, de préférence du type volumétrique, ayant un tube d'aspiration 6 qui plonge dans un réservoir à liquide désinfectant 7. Ce dernier pouvant être place un niveau quelconque, le sera de préférence au voisinage immédiat du local où débouche inférieurement le vide-ordures. La pompe 7 est entraînée par un moteur électrique 8, qui sera de préférence mis sous tension par l'intermédiaire d'une minuterie, ici schématisée en 9, ou d'un contacteur temporisé selon le temps pendant lequel on veut faire durer chaque injection de désinfectant. Chaque injecteur peut notamment être constitué sous forme de trompe hydraulique assurant, par des entrées d'air ambiant au niveau des gicleurs, une émulsion du liquide désinfectant conduisant à une fine pulvérisation de celui-ci dans la colonne à désinfecter. Les injecteurs peuvent aussi être du type produisant chacun deux jets se rencontrant l'un l'autre pour obtenir la pulvérisation désirée du liquide. Une variante de réalisation de la délivrance du liquide désinfectant sous pression peut consister avantageusement, lorsque 1' immeuble est raccordé à un réseau d'air comprimé ou dispose d'un tel réseau en propre, à utiliser cet air comprimé pour refouler le liquide désinfectant dans la canalisation 4, par exemple en maintenant le réservoir 7 sous pression et en y faisant directement plonger la canalisation 4 d'alimentation des injecteurs pourvue à la sortie du réservoir d'un robinet à commande manuelle ou électromagnétique, dont l'ouverture autorisera l'injection et la fermeture l'arrêtera. Une telle variante peut aussi se concevoir avec son propre groupe motocompresseur. Avec une commande él.ectrique de mise en fonctionnement temporisé du dispositif, la désinfection peut aussi être entièrement automatisée en plaçant la minuerie ou l'or- gane de temporisation sous la dépendance d'une horloge de commande. REVENDICATIONS 1. Dispositif de désinfection de colonne de vide-ordures, caractérisé en ce qutil comprend des injecteurs de liquide désinfectant étagés le long de la colonne et reliés par une canalisation à une source de délivrance du liquide désinfectant sous pression, permettant une désinfection semi-continue de la colonne. 2. Dispositif de désinfection d'après 1, caractérisé en ce que les injecteurs sont constitués sous forme de trompe hydraulique assurant une émulsion du liquide désinfectant avec l'air ambiant. 3. Dispositif de désinfection d'après 1, caractérisé en ce que la délivrance du désinfectant sous pression est effectuée à l'aide d'un groupe motopompe puisant dans un réservoir de désinfectant et refoulant dans ladite canalisation. 4. Dispositif de désinfection d'après 1, caractérisé en ce que la délivrance du désinfectant sous pression est effectuée par mise sous pression d'air comprimé d'un réservoir de désinfectant dans lequel plonge ladite canalisation, pourvue d'un robinet de commande d'injection.
|
"TECHNIQUES PERTAINING TO DOCUMENT PRINTING\n\nTechniques pertaining to printing a document are disc(...TRUNCATED)
|
"La présente invention a pour objet un appareil médical entrant dans la catégorie de ceux utilis(...TRUNCATED)
|
End of preview. Expand
in Data Studio
README.md exists but content is empty.
- Downloads last month
- 7