Classifications

• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
  • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
  • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
  • G11B7/0908—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for focusing only

Definitions

• the present invention relates to a technique for generating various servo error signals in an optical disk recording / reproducing apparatus.
• FIG. 3 is a block diagram of an optical disk device using an error signal generation device 200.
• Reference numeral 201 denotes an optical disk
• reference numeral 202 denotes a light beam irradiation unit for irradiating the optical disk 201 with a light beam.
• Reference numeral 203 denotes a light detection unit, which includes a plurality of photodetectors for detecting reflected light or transmitted light of a light beam from the optical disk 201.
• Reference numeral 204 denotes an error unified signal generation unit, which generates two signals serving as sources of the error signal from a plurality of outputs from the light detection unit 203.
• the error signal generation device 204 is a device for generating an error signal from the output from the error unit signal generation unit 204.
• Reference numeral 205 denotes an adjustment unit, which applies a gain and an offset to two signals which are sources of the error signal from the error source signal generation unit 204.
• Reference numeral 206 denotes a balance calculation unit, which performs a differential calculation by applying a gain balance to two outputs from the adjustment unit 205.
• the adjustment unit is adjusted so that the output signal amplitude of the adjustment unit 205 falls within the D range.
• D range dynamic range
• the gain and offset values of 205 when handling signals that are offset between when the focus is out of focus and when the focus is in focus, the output signal amplitude of the adjustment unit 205 when focusing on the D range becomes small, and the balance calculation unit 20 Error signal amplitude after differential operation by 6, small error signal The accuracy of is reduced.
• An object of the present invention is to enable a highly accurate error signal to be obtained even when an optical disc apparatus handles a signal that is offset between when the focus is out of focus and when the focus is in focus.
• the offset amount from the calculation reference level of the balance calculation is obtained for the signal at the time of out-of-focus, and the balance calculation is performed only for the signal at the time of the focus, and then the correction corresponding to the offset amount is performed. This allows the D range to be used to the maximum during focusing and improves the accuracy of the error signal.
• FIG. 1 is a block diagram of an optical disk device using an error signal generation device according to the present invention.
• FIG. 2 is a diagram showing an error signal generation operation in the error signal generation device in FIG.
• FIG. 3 is a schematic diagram showing an input signal adjustment operation in the error signal generation device in FIG.
• FIG. 4 is a detailed diagram showing an input signal adjustment operation in the error signal generation device in FIG.
• FIG. 5 is a diagram showing an example of the internal configuration of the balance correction value adjustment unit in FIG.
• FIG. 6 is a diagram showing another example of the internal configuration of the balance correction value adjusting unit in FIG.
• FIG. 7 is a diagram showing still another internal configuration example of the balance correction value adjustment unit in FIG.
• FIG. 8 is a diagram showing still another example of the internal configuration of the balance correction value adjustment unit in FIG. 1.
• FIG. 9 is a diagram showing an offset adjustment operation in the error signal generation device in FIG.
• FIG. 10 is a diagram showing a configuration example of the signal measurement unit in FIG.
• FIG. 11 is a diagram showing another configuration example of the signal measurement unit in FIG.
• FIG. 12 is a diagram showing still another configuration example of the signal measurement unit in FIG.
• FIG. 13 is a diagram illustrating a gain adjustment operation in the error signal generation device in FIG.
• FIG. 14 is a diagram illustrating another gain adjustment operation in the error signal generation device in FIG.
• FIG. 15 is a diagram illustrating a configuration example of the signal measurement unit in FIGS. 13 and 14.
• FIG. 16 is a diagram illustrating another configuration example of the signal measurement unit in FIGS. 13 and 14.
• FIG. 17 is a diagram showing a calibration operation in the error signal generation device in FIG.
• FIG. 18 is a diagram showing a gain calibration operation in the error signal generation device in FIG.
• FIG. 19 is a diagram showing an offset calibration operation in the error signal generation device in FIG.
• FIG. 20 is a block diagram of an optical disk device using a conventional error signal generation device.
• FIG. 1 is a block diagram of an optical disk device using an error signal generation device 100 according to the present invention.
• Reference numeral 101 denotes an optical disk
• 102 denotes a light beam irradiation unit for irradiating the optical disk 101 with a light beam.
• Reference numeral 103 denotes a photodetection unit, which includes a plurality of photodetectors for detecting reflected light or transmitted light of a light beam from the optical disc 101.
• Reference numeral 104 denotes an error unified signal generation unit, which generates two signals serving as error signal sources from a plurality of outputs from the photodetection unit 103.
• Reference numeral 105 denotes a focus monitoring unit which detects whether or not the force of the light beam is focused on the optical disc 101 based on a plurality of outputs from the light detection unit 103.
• the error signal generation device 100 is a device for generating an error signal from the output from the error source signal generation unit 104.
• Reference numeral 106 denotes an adjustment unit that applies an offset and a gain to two signals that are the source of the error signal from the error source signal generation unit 104.
• Reference numeral 107 denotes a balance operation unit that performs a differential operation by applying a gain balance to two outputs from the adjustment unit 106.
• Reference numeral 108 denotes a signal measurement unit that measures two outputs from the adjustment unit 106.
• Reference numeral 109 denotes an offset amount learning unit, which is an adjustment unit 106-2 based on a signal indicating the convergence state of the light beam from the focus monitoring unit 105 and the measurement result of the signal measurement unit 108.
• Reference numeral 110 denotes a balance correction value adjustment unit, which is used to calculate a balance based on the balance value information from the balance calculation unit 107 and the offset amount when the focus is out of focus from the offset amount learning unit 109. Determine the correction value.
• 1 1 1 is a balancer correction unit which adds information on the correction value of the balance correction value adjustment unit 110 to the output of the balance calculation unit 107.
• FIG. 2 shows an error signal generation operation in the error signal generation device 100 in FIG.
• the signal measurement unit 108 uses the balance operation unit 107 of the output of the adjustment unit 106 when the focus is out of focus to calculate the offset amount (a, b) is measured.
• the balance correction value adjustment unit 110 a correction value is determined from the measured offset amounts a and b and the balance value B a1 used in the balance calculation.
• the balancer correction unit 111 adds the correction value determined by the balance correction value adjustment unit 110 to the output result of the balance calculation unit 107, and corrects the balance calculation, thereby defocusing. Even if the signal has an offset amount at the time of focusing, a highly accurate balance calculation can be performed.
• the error signal generation device 100 in FIG. 1 calculates the offset amount from the balance calculation reference level of the input signal when the focus is out of focus, calculates the balance only for the signal when the focus is in focus, and then performs the offset calculation. Make corrections appropriate for the amount.
• the balance calculation can be performed.
• the D range can be used widely during focusing, and the error signal accuracy is improved.
• FIG. 3 shows an outline of an input signal adjustment operation in the error signal generation device 100 in FIG.
• the D range immediately after the output of the adjustment unit 106 is limited to a certain value.
• the gain and offset of the adjustment unit 106 are determined in advance so that the adjusted signal falls within the D range.
• there is an A / D converter, etc. May be limited to Thus, even when the D range before the balance calculation is limited by the A / D converter or the like, the input signal can be adjusted to enter the D range to enable the balance calculation.
• FIG. 4 shows the details of the input signal adjustment operation in the error signal generation device 100 in FIG.
• the offset amount learning unit 109 adjusts the offset and the gain of the adjustment unit 106 twice, that is, when the focus is in focus and when the focus is out of focus, and the offset amount when the focus is out of focus and the focus amount when the focus is in focus. From the gain and the setting of each gain and offset at the time of out-of-focus, an offset amount of the signal at the time of out-of-focus in the gain and the offset at the time of focusing is calculated.
• Offset amount when focus is out of focus a Gain setting when focus is focused Gl
• Offset setting when focus is focused Ofs 1 Gain setting when focus is out of focus G2
• the offset setting of Ofs2 is (a-Ofs1), it can be represented by ZGlxG2 + Ofs2.
• the gain and the offset at the time of focusing may be set so that the output signal of the adjusting unit 106 when the focus is out of focus exceeds the output D range of the adjusting unit 106.
• the amount of offset of the input signal at the time of out-of-focus is obtained from the gain and offset settings of the adjustment unit 106 at the time of focusing and out-of-focus. Since the output exceeds the output D range, the D range can be used widely and highly accurate balance calculation can be performed.
• FIG. 5 shows an example of the internal configuration of the balance correction value adjustment unit 110 in FIG.
• the balance correction value adjustment unit 110 shown in FIG. 5 calculates the correction value of the balance calculation from the two outputs (a, b) of the offset amount learning unit 109 and the balance value (B a 1) of the balance calculation unit 107. (1 + Bal) One b (1-Bal). With this, a highly accurate balance correction can always be performed by recalculating and correcting the balance calculation correction value for the dynamic fluctuation of the balance value (Bal). Further, the arithmetic unit can be shared by the balance calculation unit 107 and the balance correction value adjustment unit 110.
• FIG. 6 shows another internal configuration example of the balance correction value adjustment unit 110 in FIG.
• FIG. 7 shows still another internal configuration example of the balance correction value adjustment unit 110 in FIG.
• a and b are sufficiently large and the difference between a and b is small with respect to the two outputs (a, b) of the offset amount learning unit 109.
• the correction value of the balance calculation is set to Bal (a + b).
• the number of arithmetic units of the balance correction value adjustment unit 110 can be further reduced, and the arithmetic speed can be improved.
• FIG. 8 shows still another internal configuration example of the balance correction value adjustment unit 110 in FIG.
• the balance correction value adjustment unit 110 in FIG. 8 sets the two outputs of the offset amount learning unit 109 to a common value by making the gain and offset values of the adjustment unit 106 the same for the two inputs. a), and from the balance value (Bal) of the balance calculation unit 107, the correction value of the balance calculation is set to 2 ⁇ Balxa.
• the gain and offset of the adjustment unit 106 By sharing the gain and offset of the adjustment unit 106 in this way, the number of arithmetic units can be reduced and the arithmetic speed can be improved.
• FIG. 9 shows an offset adjustment operation in the error signal generation device 100 in FIG.
• the signal measurement unit 108 in FIG. 9 measures the average value of the output signals of the adjustment unit 106 when the focus is out of focus and when the focus is in focus.
• the offset amount learning unit 109 determines the offset value of the adjustment unit 106 so that the average value becomes the calculation reference level of the balance calculation.
• FIG. 10 shows a configuration example of the signal measurement unit 108 in FIG. Figure 10 signal
• the measurement unit 108 measures the time average of the output signal of the adjustment unit 106 when the focus is out of focus and at the time of focusing, and sets the time average as the average value of the output signal of the adjustment unit 106.
• the signal measurement unit 108 can be realized by a simple arithmetic unit.
• FIG. 11 shows another configuration example of the signal measurement unit 108 in FIG.
• the signal measurement unit 108 in FIG. 11 measures the maximum value and the minimum value of the output signal of the adjustment unit 106 at the time of out-of-focus and in-focus, and calculates the intermediate value between the maximum value and the minimum value.
• the value shall be the average value of the output signals of the adjustment unit 106 at the time of focusing.
• FIG. 12 shows still another configuration example of the signal measurement unit 108 in FIG.
• the signal measurement unit 108 in FIG. 12 measures the maximum value and the minimum value of the output signal of the adjustment unit 106 at the time of out-of-focus and at the time of focusing for a certain period of time. And the average value of the respective averages is taken as the average value of the output signals of the adjustment unit 106 at the time of focusing. This makes it possible to perform highly accurate balance calculation while avoiding the influence of noise.
• FIG. 13 shows a gain adjustment operation in the error signal generation device 100 in FIG.
• the signal measurement unit 108 of FIG. 13 measures the amplitude of the output signal of the adjustment unit 106 during focusing.
• the offset amount learning unit 109 is adjusted so that the amplitude of the output signal of the adjusting unit 106 at the time of focusing becomes a fixed ratio to the D range immediately after the output of the adjusting unit 106.
• the offset amount learning unit 109 determines the gain value of the adjustment unit 106 from the ratio between the amplitude of the output signal of the adjustment unit 106 and the D range immediately after the output of the adjustment unit 106. To determine.
• the gain value of the adjustment unit 106 is set so that the amplitude of the output signal of the adjustment unit 106 at the time of focusing is about 80% of the D range immediately after the output of the adjustment unit 106. Should be determined.
• the optical disk 101 for recording and reproducing the amplitude of the input signal and the optical disk Even when it depends on the focal position of the light beam on the light source 101, a highly accurate balance calculation can be performed. Even when the input signal amplitude fluctuates dynamically, highly accurate balance calculation can be performed without exceeding the D range.
• FIG. 14 shows another gain adjustment operation in the error signal generation device 100 in FIG.
• the offset amount learning unit 109 in FIG. 14 minimizes the gain value of the adjustment unit 106, and then the amplitude of the output signal of the adjustment unit 106 becomes the D range immediately after the output of the adjustment unit 106.
• the gain value of the adjustment unit 106 is adjusted by gradually increasing the gain value of the adjustment unit 106 until the ratio exceeds a certain fixed ratio. As a result, even when there is an error in the gain and offset set values of the adjustment unit 106, a highly accurate balance calculation can be performed.
• FIG. 15 shows a configuration example of the signal measurement unit 108 in FIGS. 13 and 14.
• the signal measurement unit 1 ⁇ 8 in Fig. 15 measures the maximum value and the minimum value of the output signal of the adjustment unit 106 during focusing, and adjusts the difference between the maximum value and the minimum value.
• the output signal amplitude of 106 is assumed.
• the signal measurement unit 108 can be realized by a simple arithmetic unit.
• FIG. 16 shows another configuration example of the signal measurement unit 108 in FIGS. 13 and 14.
• the signal measurement unit 108 in FIG. 16 measures the maximum value and the minimum value of the output signal of the adjustment unit 106 at the time of focusing within a certain period of time, and performs the measurement several times. An average value of each of the maximum value and the minimum value is obtained, and the difference between the average values is used as the amplitude of the output signal of the adjustment unit 106. Thereby, even when the input signal is offset and the center of the amplitude is different from the time average value, highly accurate balance calculation can be performed.
• the gain value of the adjustment unit 106 may be determined in advance according to the type of the medium of the optical disk 101. As a result, the error signal generation device 100 can be easily realized.
• FIG. 17 shows a calibration operation in the error signal generation device 100 in FIG.
• the offset amount learning unit 109 is set. Adjusts the gain and offset values of the adjustment unit 106 to calibrate the gain and offset.
• a highly accurate balance calculation can be performed.
• FIG. 18 shows a gain calibration operation in the error signal generation device 100 in FIG.
• the offset amount learning unit 109 changes the gain of the adjustment unit 106 while keeping the offset amount constant at the time of out-of-focus, and the signal measurement unit 108 adjusts the adjustment unit 106.
• the amount of gain change with respect to the gain setting value is calculated.
• the configuration of FIG. 17 can be realized with a simple algorithm.
• FIG. 19 shows an offset calibration operation in the error signal generator 100 in FIG.
• the offset amount learning unit 1109 changes the offset of the adjustment unit 106 while keeping the gain amount constant when the focus is out of focus, and the signal measurement unit 108 adjusts the offset unit 106.
• the offset change amount with respect to the offset set value is calculated.
• the configuration in FIG. 17 can be realized with a simple algorithm.
• the error signal generation device can use the D range to the maximum at the time of focusing and has the effect of improving the accuracy of the error signal. Useful for devices and the like.

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• Optical Recording Or Reproduction (AREA)
• Moving Of The Head For Recording And Reproducing By Optical Means (AREA)

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Citations (3)

• 2003
  • 2003-09-24 CN CN 03821908 patent/CN1682292A/zh active Pending
  • 2003-09-24 WO PCT/JP2003/012179 patent/WO2004093068A1/ja active Application Filing
  • 2003-09-24 JP JP2004570909A patent/JPWO2004093068A1/ja not_active Withdrawn

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