JP2008287800A - Optical disk reproduction device and automatic adjustment method of optical disk reproduction device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide "an optical disk reproduction device and an automatic adjustment method of the optical disk reproduction device" which can appropriately perform automatic adjustment of servo characteristics. <P>SOLUTION: When a clip arises in an FE signal output by an FE amplifier 67 of a head amplifier 106, a system controller 109 sets frequency characteristics of an FE equalizer 811 at small gain frequency characteristics where gains of respective frequency bands are small, sets a gain of an FE servo gain adjusting section 812 at the minimum gain, and then causes the FE servo characteristics to be automatically adjusted. In the automatic adjustment, an FE servo automatic adjustment control section 813 calculates an sets the frequency characteristics of the FE equalizer 811 and the gain of the FE servo gain adjusting section 812 to provide desired servo characteristics while gradually varying the frequency characteristics of the FE equalizer 811 and the gain of the FE servo gain adjusting section 812 starting from an initial value according to a response to a disturbance introduced via an FE disturbance introducer 814. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technique for automatically adjusting a servo system in an optical disk reproducing apparatus for reproducing an optical disk as a storage medium.

The technology for automatically adjusting the servo system in an optical disk playback device that performs optical disk playback is based on the RF signal generated from the pickup detection signal, the focus error signal, and the tracking error signal prior to the start of optical disk playback. There is known a technique for automatically adjusting various servo characteristics such as a gain for focusing servo control and tracking servo control (for example, Patent Document 1).
JP-A-5-314504

Some optical discs have an abnormally small ratio of the amplitude of the RF signal, which is the recording signal component in the detection signal of the pickup, to the level of the upper envelope of the RF signal including the DC component.
In such a case, in order to set the amplitude of the RF signal to a predetermined level, if the pickup detection signal is uniformly amplified with a large amplification factor, the focus error signal and tracking error signal generated from the pickup detection signal In some cases, the gain becomes excessive and servo control oscillates, and various servo characteristics such as the focusing servo control gain and tracking servo control gain described above cannot be automatically adjusted appropriately. It should be noted that the RF signal needs to have a certain level of magnitude since the ripple is used to detect crossing of tracks during the automatic adjustment of the servo characteristics of the tracking servo.

  Accordingly, an object of the present invention is to enable appropriate automatic adjustment of servo characteristics even when the amplitude ratio of an RF signal is small in an optical disc reproducing apparatus.

  In order to achieve the above object, the present invention provides an optical disk reproducing apparatus for reproducing an optical disk, a pickup, a tracking error signal generating unit for generating a tracking error signal based on an output signal of the pickup, and a head for amplifying the tracking error signal An amplifier, a tracking control unit that performs tracking control according to the tracking error signal amplified by the head amplifier, and a tracking control gain according to the tracking error signal of the tracking control unit so that a desired tracking servo characteristic can be obtained. An automatic adjustment unit that automatically adjusts the first gain when the level of the tracking error signal amplified by the head amplifier is not larger than a predetermined level in the automatic adjustment unit. As the gain of Adjustment is started, and when the level of the tracking error signal amplified by the head amplifier is greater than a predetermined level, the automatic adjustment is started using a second gain smaller than the first gain as a gain at the start of the automatic adjustment. It is what you do.

  Here, in such an optical disc reproducing apparatus, the tracking control unit adjusts the gain for each frequency band of the tracking error signal, and the tracking error signal for which the tracking equalizer has adjusted the gain for each frequency band. A tracking gain adjustment unit that amplifies the tracking gain, and a tracking driver that moves the pickup in the radial direction of the optical disk based on the tracking error signal amplified by the tracking gain adjustment unit. The first gain defines a first frequency characteristic of gain adjustment for each frequency band of the tracking equalizer and a first gain of the amplification of the tracking gain adjustment unit, and the second gain. Is the tracking equalizer A second frequency characteristic the gain is small in each frequency band than the first frequency characteristic, and defines a first amplification factor smaller than the first amplification factor of the amplification of the tracking gain adjustment unit.

  According to such an optical disk reproducing apparatus, when the tracking error signal is excessively amplified by the head amplifier by appropriately setting the predetermined level, the tracking control according to the tracking error signal of the tracking control unit is performed. Can be set to a second gain smaller than the first gain, which is a gain at the start of normal automatic adjustment, and automatic adjustment of the gain of the tracking control unit can be started. Therefore, by appropriately setting the second gain, it is possible to eliminate a situation where servo control oscillates due to the gain being too large at the start of automatic adjustment, and proper automatic adjustment cannot be performed. It becomes like this. Therefore, when the head amplifier is such that the tracking error signal is amplified with an amplification factor corresponding to the amplitude of the RF signal generated from the output signal of the pickup, the amplitude of the RF signal is reduced. Even when the tracking error signal is excessively amplified by the head amplifier because the ratio of the RF signal to the upper envelope level is abnormally small, appropriate automatic adjustment can be realized. Further, when the tracking error signal is appropriately amplified by the head amplifier, a quick automatic adjustment can be realized by using the first gain larger than the second gain as the gain at the start of the automatic adjustment.

  In order to achieve the above object, the present invention provides an optical disk reproducing apparatus for reproducing an optical disk, a pickup, a focus error signal generating unit that generates a focus error signal based on an output signal of the pickup, and an amplification of the focus error signal A desired focus servo characteristic for obtaining a head control amplifier, a focus control unit that performs focus control according to the focus error signal amplified by the head amplifier, and a focus control gain according to the focus error signal of the focus control unit. An automatic adjustment unit that automatically adjusts the first gain when the level of the focus error signal amplified by the head amplifier is not greater than a predetermined level in the automatic adjustment unit. Start the automatic adjustment as a gain at the start, When the level of the focus error signal amplified by the head amplifier is greater than a predetermined level, the automatic adjustment is started with a second gain smaller than the first gain as the gain at the start of the automatic adjustment. It is.

  Here, in such an optical disc reproducing apparatus, the focus control unit includes a focus equalizer that adjusts a gain of each frequency band of the focus error signal, and the focus error signal that the focus equalizer adjusts a gain of each frequency band. And a focus driver that moves a focus position of the pickup based on the focus error signal amplified by the focus gain adjustment unit. The gain defines a first frequency characteristic of gain adjustment for each frequency band of the focus equalizer and a first amplification factor of the amplification of the focus gain adjustment unit, and the second gain is the focus gain Each frequency than the first frequency characteristic of the equalizer A second frequency characteristic the gain is small bandwidth, preferably set to defines a first amplification factor smaller than the first amplification factor of the amplification of the focus gain adjustment unit.

  According to such an optical disc reproducing apparatus, when the focus error signal is excessively amplified by a head amplifier by appropriately setting the predetermined level, the focus control unit responds to the focus error signal. The focus control gain can be set to a second gain smaller than the first gain, which is the gain at the start of normal automatic adjustment, and the automatic adjustment of the gain of the focus control unit can be started. Therefore, by appropriately setting the second gain, it is possible to eliminate a situation where servo control oscillates due to the gain being too large at the start of automatic adjustment, and proper automatic adjustment cannot be performed. It becomes like this. Therefore, when the head amplifier is such that the focus error signal is amplified by an amplification factor corresponding to the amplitude of the RF signal generated from the output signal of the pickup, the amplitude of the RF signal is reduced. Even when the focus error signal is excessively amplified by the head amplifier because the ratio of the RF signal to the upper envelope level is abnormally small, appropriate automatic adjustment can be realized. In addition, when the focus error signal is appropriately amplified by the head amplifier, the first gain larger than the second gain can be used as a gain at the start of automatic adjustment so that a quick automatic adjustment can be performed. .

  As described above, according to the present invention, in the optical disk reproducing apparatus, even when the amplitude ratio of the RF signal is small, the servo characteristics can be automatically adjusted appropriately.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 shows a configuration of an optical disc drive according to the present embodiment.
As shown in the figure, the optical disk drive 1 includes a clamper 101, a turntable 102, a spindle motor 103, a feed motor 104, a pickup 105, a head amplifier 106, a signal processing unit 107, a servo control unit 108, a system controller 109, and a host device 2. A host interface 110 to be connected is provided.

  In such a configuration, the clamper 101 and the turntable 102 clamp the optical disc 3 such as a DVD mounted on the optical disc drive 1, and the spindle motor 103 rotates the optical disc 3 clamped between the turntable 102 and the clamper 101. To do. The feed motor 104 performs a seek operation for moving the pickup 105 in the radial direction of the optical disc 3 and a tracking adjustment operation.

  Next, the pickup 105 includes a laser light source, a photoelectric element, and an objective lens that condenses the irradiation light from the laser light source on the recording layer of the optical disc 3 and guides the reflected light from the recording layer of the optical disc 3 to the photoelectric element. A focus actuator that adjusts the focal position by moving the objective lens in a direction perpendicular to the signal recording surface of the optical disc 3, and a tracking actuator that performs tracking adjustment by moving the objective lens in the radial direction of the optical disc 3. It is out. The pickup 105 outputs a detection signal obtained by photoelectrically converting the reflected light from the signal recording surface of the optical disc 3 by a photoelectric element.

  Next, the head amplifier 106 generates an RF signal from the detection signal output from the pickup 105 and outputs the RF signal to the signal processing unit 107. Further, the head amplifier 106 generates an RF ripple signal (RFRP), a focus error signal (FE), and a tracking error signal (TE) representing the ripple of the RF signal from the detection signal output from the pickup 105.

  Next, the signal processing unit 107 demodulates data from the RF signal output from the head amplifier 106, detects and corrects errors that occur in the demodulated data, and reproduces data recorded on the optical disc 3. The reproduced data is sent to the host interface 110.

The servo control unit 108 controls the seek operation of the feed motor 104 according to the control of the system controller 109, and performs focus servo control and tracking servo control according to the focus error signal (FE) and tracking error signal (TE). Do. Details of the focus servo control and tracking servo control will be described later.
Then, the system controller 109 controls the above-described units, reproduces the data requested by the host command from the optical disc 3 according to the host command received from the host apparatus 2 via the host interface 110, and performs the host interface 110. A read process for transferring to the host device 2 via the host is performed.

Here, FIG. 2 shows the configuration of the head amplifier 106 and the servo control unit 108.
However, here, the pickup 105 includes six photoelectric elements a to f arranged as shown in the figure with the upper and lower sides in the figure as the circumferential direction of the optical disk 3 (direction along the track). The A + C signal obtained by adding the output signals, the B + D signal obtained by adding the output signals of the photoelectric elements b and d, the E signal output by the photoelectric element e, and the F signal output by the photoelectric element f are output as the detection signals. An example of the case will be described.

  As shown in the figure, the head amplifier 106 uniformly amplifies each signal output from the pickup 105 with the gain GP set by the system controller 109, and each signal output from the preamplifier 61 from the system controller 109. Each has a balance adjustment amplifier 62 that amplifies with an individually set gain. Here, the system controller 109 individually controls the individual gain of each signal in the balance adjustment amplifier 62 with the control signal BLCNT.

  Next, the head amplifier 106 adds an A + C signal output from the balance adjustment amplifier 62 and a B + D signal to generate an RF signal, an RF calculator 63, and an A + C signal output from the balance adjustment amplifier 62. The FE calculator 64 subtracts the B + D signal from the FE signal to obtain the FE signal, and the TE calculator 65 subtracts the F signal from the E signal output from the balance adjustment amplifier 62 to obtain the TE signal. Here, the FE computing unit 64 also has a function of adjusting the offset of the FE signal by the FE offset FEOS output from the system controller 109, and the TE computing unit 65 performs the TE by the TE offset TEOS output from the system controller 109. It also has the function of adjusting the offset of the signal.

  The head amplifier 106 also amplifies the AC component of the RF signal generated by the RF calculator 63 with the gain GRF set by the system controller 109, and the FE signal generated by the FE calculator 64 as a system controller. FE amplifier 67 that amplifies with gain GFE set from 109 and TE amplifier 68 that amplifies the TE signal generated by TE calculator 65 with gain GTE set from system controller 109.

  The head amplifier 106 includes a level detection unit 69 and an RF amplifier 66 that detect levels RFL, FEL, and TEL of the RF signal, the FE signal, and the TE signal amplified by the RF amplifier 66, the FE amplifier 67, and the TE amplifier 68, respectively. An RF ripple generation unit 60 for generating an RF ripple signal RFRP that represents the ripple of the RF signal amplified in (1).

Next, the servo control unit 108 includes a focus servo control unit 81, a focus driver 82, a tracking servo control unit 83, and a tracking driver 84.
The focus servo control unit 81 includes an FE equalizer 811, an FE servo gain adjustment unit 812, an FE servo automatic adjustment control unit 813, and an FE disturbance introducer 814. The ftracking servo control unit includes a TE equalizer 821 and a TE. A servo gain adjustment unit 822, a TE servo automatic adjustment control unit 823, and a TE disturbance introducer 824 are provided.

  Then, in the focus servo control unit 81, the FE equalizer 811 performs equalization processing on the FE signal output from the FE amplifier 67 of the head amplifier 106 by the frequency gain characteristic set by the FE servo automatic adjustment control unit 813. The servo gain adjustment unit 812 amplifies the FE signal output from the FE equalizer 811 with the gain set by the FE servo automatic adjustment control unit 813 and outputs the amplified signal to the focus driver 82. On the other hand, when the system controller 109 instructs the FE servo automatic adjustment control unit 813 to execute FE servo automatic adjustment, the FE servo automatic adjustment control unit 813 introduces disturbance to the FE signal input to the FE equalizer 811 via the FE disturbance introducer 814. Based on the response to the disturbance appearing in the FE signal output from the head amplifier 106, the frequency gain characteristic of the FE equalizer 811 and the gain of the FE servo gain adjustment unit 812 that obtain desired servo characteristics are calculated while gradually changing them. Then, the FE equalizer 811 and the FE servo gain adjustment unit 812 are set.

Then, the focus driver 82 controls the focus actuator of the pickup 105 according to the FE signal output from the FE servo gain adjustment unit 812 under the control of the system controller 109, thereby realizing focusing of the pickup 105.
On the other hand, in the tracking servo control unit 83, the TE equalizer 821 performs equalization processing on the TE signal output from the TE amplifier 68 of the head amplifier 106 by the frequency gain characteristic set by the TE servo automatic adjustment control unit 823, and TE The servo gain adjustment unit 822 amplifies the TE signal output from the TE equalizer 821 by the gain set by the TE servo automatic adjustment control unit 823 and outputs the amplified signal to the tracking driver 84. When the TE servo automatic adjustment control unit 823 is instructed to execute the TE servo automatic adjustment from the system controller 109, the TE servo automatic adjustment control unit 823 introduces a disturbance to the TE signal input to the TE equalizer 821 via the TE disturbance introducer 824, Based on the response to the disturbance appearing in the TE signal output from the head amplifier 106, the frequency gain characteristic of the TE equalizer 821 that obtains a desired servo characteristic and the gain of the TE servo gain adjustment unit 822 are calculated while gradually changing them. Then, the TE equalizer 821 and the TE servo gain adjustment unit 822 are set.

  Then, the tracking driver 84 controls the tracking actuator and the feed motor 104 of the pickup 105 according to the TE signal output from the TE servo gain adjustment unit 822 under the control of the system controller 109, thereby realizing tracking of the pickup 105. . The tracking driver 84 tracks the pickup 105 by controlling the tracking actuator and the feed motor 104 of the pickup 105 in accordance with a seek control signal output from the system controller 109 while referring to the RFRP signal when a seek operation is performed. Move between.

In such a configuration, the system controller 109 performs automatic setting of servo characteristics at the time of startup or when the optical disk 3 is mounted.
In the automatic setting of the servo characteristics, the system controller 109 first sets the gain of each signal of the balance adjustment amplifier 62 so that the deviation of the balance between the A + C signal and the B + D signal, and the E signal and the F signal is canceled. These offsets are set with the FE offset FEOS and the TE offset TEOS so that the offset of the FE signal generated by the FE calculator 64 and the offset of the TE signal generated by the TE calculator 65 are set to a desired level. adjust.

Next, the system controller 109 sets the gain characteristics of the focus servo and tracking servo in the gain characteristic setting process shown in FIG.
As shown in the figure, in this process, first, the level detection unit 69 of the head amplifier 106 detects the level FEL of the FE signal while controlling the focus driver 82 and causing the focus actuator to change the focus cyclically greatly. 302).
Then, it is determined from the level FEL of the FE signal whether or not the mounted optical disk 3 is a CD-RW (step 304). Here, when the level FEL of the FE signal is smaller than a predetermined level, it is determined that the mounted optical disk 3 is a CD-RW.
If the mounted optical disk 3 is a CD-RW (step 306), the gain GP of the preamplifier 61 is set to a large gain (step 324). Here, the preamplifier 61 is configured so that the gain GP can be switched between a standard gain and a gain that is a gain larger than the standard gain. Note that the initial value of the gain GP of the preamplifier 61 at the start of the gain characteristic setting process is a standard gain.

  Then, based on the level FEL of the FE signal detected by the level detection unit 69, the gain GFE of the FE amplifier 67 is roughly adjusted so that the FE signal output from the FE amplifier 67 approaches a predetermined level to detect the level. Based on the level TEL of the TE signal detected by the unit 69, the gain GTE of the TE amplifier 68 is roughly adjusted so that the TE signal output from the TE amplifier 68 approaches a predetermined level, and the RF signal detected by the level detection unit 69 Based on the level RFL, the gain GRF of the RF amplifier 66 is adjusted so that the RF signal output from the RF amplifier 66 becomes a predetermined level (step 326). Note that the TE signal level TEL and the RF signal level RFL are set, for example, with the pickup 105 via the tracking driver 84 in a state in which focus servo for controlling the focus actuator is started in accordance with the FE signal input to the focus driver 82. Detect while traversing the track. Then, the process proceeds to Step 316.

  On the other hand, if it is determined in step 306 that the optical disk 3 is not a CD-RW, the gain GFE of the FE amplifier 67 and the TE amplifier 68 are maintained in the same manner as in step 326 while the gain GP of the preamplifier 61 is kept at the standard gain. The gain GTE and the gain GRF of the RF amplifier 66 are adjusted so that the output signal of each amplifier approaches a predetermined level (step 308).

Then, the level RFL of the RF signal is acquired again from the level detection unit 69, and it is determined again whether or not the mounted optical disc 3 is a CD-RW (step 312). Here, when the amplitude level of the RF signal input to the RF amplifier 66, which is obtained from the RF signal level RFL and the gain GRF of the RF amplifier 66, is smaller than a predetermined level, the mounted optical disk 3 is a CD-RW. Is determined.
If the mounted optical disk 3 is a CD-RW (step 314), the process proceeds to step 324 described above. If the mounted optical disk 3 is not a CD-RW (step 314), step 316 is performed. Proceed to
When the process proceeds to step 316 in this way, the FE signal output from the FE amplifier 67 is determined based on whether or not the FE level FEL detected by the level detection unit 69 matches the maximum output value of the FE amplifier 67. It is determined whether or not clipping (saturation) has occurred.
If no clipping occurs in the FE signal (step 316), the FE servo automatic adjustment control unit 813 is instructed to execute FE servo automatic adjustment (step 318), and the frequency characteristics and FE servo gain adjustment of the FE equalizer 811 are instructed. The gain of the unit 812 is set. Then, the process proceeds to step 320. Here, in the initial state, the frequency characteristic of the FE equalizer 811 is set to a predetermined standard frequency characteristic, and the gain of the FE servo gain adjustment unit 812 is set to the median value of the gain adjustment width of the FE servo gain adjustment unit 812. . As a result, when clipping (saturation) does not occur in the FE signal, the FE servo automatic adjustment control unit 813 has the frequency characteristic of the FE equalizer 811 as the standard frequency characteristic, and the gain of the FE servo gain adjustment unit 812 is gain. The FE servo automatic adjustment will be started with the median adjustment width. In this FE servo automatic adjustment, as described above, the FE servo automatic adjustment control unit 813 determines the frequency characteristics of the FE equalizer 811 and the FE servo gain according to the response to the disturbance introduced through the FE disturbance introducer 814. A desired servo characteristic can be obtained while gradually changing the gain of the adjustment unit 812 from the initial value (standard frequency characteristic, median value of the gain adjustment range). The frequency characteristic of the FE equalizer 811 and the FE servo gain adjustment unit 812 The gain is calculated and set in the FE equalizer 811 and the FE servo gain adjustment unit 812.

  On the other hand, if it is determined in step 316 that clipping has occurred in the FE signal, first, the FE servo automatic adjustment control unit 813 sets the gains of the FE equalizer 811 and the FE servo gain adjustment unit 812 to a value smaller than the standard. To set. That is, the frequency characteristic of the FE equalizer 811 is set to the gain small frequency characteristic in which the gain of each frequency band is smaller than the standard frequency characteristic, and the gain of the FE servo gain adjustment unit 812 is set to the minimum gain (step 328).

  Then, execution of FE servo automatic adjustment is instructed (step 318), and the frequency characteristic of the FE equalizer 811 and the gain of the FE servo gain adjustment unit 812 are set. Then, the process proceeds to step 320. As a result, when clipping (saturation) occurs in the FE signal, the FE servo automatic adjustment control unit 813 has the frequency characteristic of the FE equalizer 811 as a small gain frequency characteristic, and the gain of the FE servo gain adjustment unit 812 is The FE servo automatic adjustment is started in the state where the gain adjustment width is at the minimum value. In this FE servo automatic adjustment, as described above, the FE servo automatic adjustment control unit 813 determines the frequency characteristics of the FE equalizer 811 and the FE servo gain according to the response to the disturbance introduced through the FE disturbance introducer 814. The desired servo characteristics can be obtained while gradually changing the gain of the adjustment unit 812 from the initial value (the small gain frequency characteristic and the minimum value of the gain adjustment range), and the frequency characteristic of the FE equalizer 811 and the FE servo gain adjustment unit 812. Are set in the FE equalizer 811 and the FE servo gain adjustment unit 812.

Next, when the processing proceeds to step 320, the TE signal output from the TE amplifier 68 is determined based on whether or not the TE level TEL detected by the level detection unit 69 matches the maximum output value of the TE amplifier 68. Determine whether clipping (saturation) has occurred.
If no clipping occurs in the TE signal (step 320), the TE servo automatic adjustment control unit 823 is instructed to execute TE servo automatic adjustment (step 322), and the frequency characteristics of the TE equalizer 821 and the TE servo gain adjustment are adjusted. The gain of the unit 822 is set, and the process ends. Here, in the initial state, the frequency characteristic of the TE equalizer 821 is set to a predetermined standard frequency characteristic, and the gain of the TE servo gain adjustment unit 822 is set to the median value of the gain adjustment width of the TE servo gain adjustment unit 822. . As a result, when clipping (saturation) does not occur in the TE signal, the TE servo automatic adjustment control unit 823 has the frequency characteristic of the TE equalizer 821 as the standard frequency characteristic, and the gain of the TE servo gain adjustment unit 822 is gain. TE servo automatic adjustment is started in the state of the median adjustment width. In this TE servo automatic adjustment, as described above, the TE servo automatic adjustment control unit 823 determines the frequency characteristic and TE servo gain of the TE equalizer 821 according to the response to the disturbance introduced via the TE disturbance introducer 824. The desired servo characteristic can be obtained while gradually changing the gain of the adjustment unit 822 from the initial value (standard frequency characteristic, median value of the gain adjustment range). The frequency characteristic of the TE equalizer 821 and the TE servo gain adjustment unit 822 The gain is calculated and set in the TE equalizer 821 and the TE servo gain adjustment unit 822. And
On the other hand, if it is determined in step 320 that clipping has occurred in the TE signal, first, the TE servo automatic adjustment control unit 823 uses the frequency characteristics of the TE equalizer 821 and the gain of the TE servo gain adjustment unit 822 as standard. Set to a smaller value. That is, the frequency characteristic of the TE equalizer 821 is set to the gain small frequency characteristic in which the gain in each frequency band is smaller than the standard frequency characteristic, and the gain of the TE servo gain adjustment unit 822 is set to the minimum gain (step 330).

  Then, the execution of TE servo automatic adjustment is instructed (step 322), the frequency characteristic of the TE equalizer 821 and the gain of the TE servo gain adjustment unit 822 are set, and the process ends. As a result, when clipping (saturation) occurs in the TE signal, the TE servo automatic adjustment control unit 823 has the gain characteristic of the TE servo gain adjustment unit 822 in which the frequency characteristic of the TE equalizer 821 is the gain small frequency characteristic. TE servo automatic adjustment is started in the state where the gain adjustment width is at the minimum value. In this TE servo automatic adjustment, as described above, the TE servo automatic adjustment control unit 823 determines the frequency characteristic and TE servo gain of the TE equalizer 821 according to the response to the disturbance introduced via the TE disturbance introducer 824. A desired servo characteristic can be obtained while gradually changing the gain of the adjustment unit 822 from the initial value (gain small frequency characteristic, minimum value of gain adjustment range), and the frequency characteristic of the TE equalizer 821 and the TE servo gain adjustment unit 822. Are set in the TE equalizer 821 and the TE servo gain adjustment unit 822.

The gain characteristic setting process performed by the system controller 109 has been described above.
According to such gain characteristic setting processing, since the ratio of the amplitude of the RF signal to the level of the upper envelope of the RF signal is abnormally small, the focus error signal FE and the tracking error signal TE are excessively amplified by the head amplifier 106. In such a case, this is detected from the occurrence of clipping of the focus error signal FE and tracking error signal TE output from the head amplifier 106, and the gains of the focus servo control unit 81 and tracking servo control unit 83 are reduced. After setting, automatic adjustment of the gains of the focus servo control unit 81 and tracking servo control unit 83 is started. Therefore, at the start of automatic adjustment, it can be excluded that servo control oscillates due to the gain being too large and proper automatic adjustment cannot be performed. Further, when the focus error signal and the tracking control unit are appropriately amplified by the head amplifier 106, the focus servo control unit 81 and the tracking servo control unit 83 are set to relatively large gains, and then the focus servo control is performed. Since the automatic adjustment of the gain of the unit 81 and the tracking servo control unit 83 is started, a quick automatic adjustment in such a case can be realized.

  Therefore, according to this embodiment, when the amplitude ratio of the RF signal is small, even when the focus error signal FE and the tracking error signal TE are excessively amplified by the head amplifier 106, the servo characteristics are automatically adjusted appropriately. Will be able to do.

1 is a block diagram showing a configuration of an optical disc drive according to an embodiment of the present invention. It is a block diagram which shows the structure of the head amplifier and servo control part which concern on embodiment of this invention. It is a flowchart which shows the gain characteristic setting process which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Optical disk drive, 2 ... Host apparatus, 3 ... Optical disk, 60 ... RF ripple production | generation part, 61 ... Preamplifier, 62 ... Balance adjustment amplifier, 63 ... RF calculator, 64 ... FE calculator, 65 ... TE calculator, 66 ... RF amplifier, 67 ... FE amplifier, 68 ... TE amplifier, 69 ... Level detection unit, 81 ... Focus servo control unit, 82 ... Focus driver, 83 ... Tracking servo control unit, 84 ... Tracking driver, 101 ... Clamper, 102 ... Turntable, 103 ... Spindle motor, 104 ... Feed motor, 105 ... Pickup, 106 ... Head amplifier, 107 ... Signal processing unit, 108 ... Servo control unit, 109 ... System controller, 110 ... Host interface, 811 ... FE equalizer, 812 ... FE servo gain adjustment unit, 813 ... FE servo automatic adjustment system Department, 814 ... FE disturbance introducer, 821 ... TE equalizer, 822 ... TE servo gain adjustment unit, 823 ... TE servo automatic adjustment control unit, 824 ... TE disturbance introducer.

Claims (8)

An optical disk playback device for playing back an optical disk,
With a pickup,
A tracking error signal generator for generating a tracking error signal based on the output signal of the pickup;
A head amplifier that amplifies the tracking error signal;
A tracking control unit that performs tracking control according to the tracking error signal amplified by the head amplifier;
An automatic adjustment unit that automatically adjusts the tracking control gain according to the tracking error signal of the tracking control unit so as to obtain a desired tracking servo characteristic;
When the level of the tracking error signal amplified by the head amplifier is not higher than a predetermined level, the automatic adjustment unit starts the automatic adjustment using a first gain as a gain at the start of the automatic adjustment, and the head amplifier When the level of the amplified tracking error signal is larger than a predetermined level, the automatic adjustment is started using a second gain smaller than the first gain as a gain at the start of the automatic adjustment. . An optical disk reproducing apparatus according to claim 1, wherein
The tracking control unit
A tracking equalizer that adjusts the gain of each frequency band of the tracking error signal;
A tracking gain adjustment unit that amplifies the tracking error signal in which the tracking equalizer has adjusted the gain for each frequency band;
A tracking driver that moves the pickup in the radial direction of the optical disc based on the tracking error signal amplified by the tracking gain adjustment unit;
The first gain defines a first frequency characteristic of gain adjustment for each frequency band of the tracking equalizer and a first amplification factor of the amplification of the tracking gain adjustment unit, and the second gain Is a second frequency characteristic in which the gain of each frequency band is smaller than the first frequency characteristic of the tracking equalizer, and a second gain smaller than the first gain of the amplification of the tracking gain adjustment unit, An optical disc reproducing device characterized by the above. An optical disk reproducing apparatus according to claim 1 or 2, wherein
The optical disk reproducing apparatus, wherein the head amplifier amplifies the tracking error signal with an amplification factor corresponding to an amplitude of an RF signal generated from an output signal of a pickup. An optical disk playback device for playing back an optical disk,
With a pickup,
A focus error signal generation unit that generates a focus error signal based on the output signal of the pickup;
A head amplifier that amplifies the focus error signal;
A focus control unit that performs focus control according to the focus error signal amplified by the head amplifier;
An automatic adjustment unit that automatically adjusts the gain of the focus control according to the focus error signal of the focus control unit so as to obtain a desired focus servo characteristic;
When the level of the focus error signal amplified by the head amplifier is not higher than a predetermined level, the automatic adjustment unit starts the automatic adjustment using a first gain as a gain at the start of the automatic adjustment, and the head amplifier When the level of the amplified focus error signal is larger than a predetermined level, the automatic adjustment is started using a second gain smaller than the first gain as a gain at the start of the automatic adjustment. . An optical disk reproducing apparatus according to claim 1, wherein
The focus control unit
A focus equalizer for adjusting a gain for each frequency band of the focus error signal;
A focus gain adjustment unit that amplifies the focus error signal in which the focus equalizer has adjusted the gain for each frequency band; and
A focus driver that moves the focus position of the pickup based on the focus error signal amplified by the focus gain adjustment unit;
The first gain defines a first frequency characteristic of gain adjustment for each frequency band of the focus equalizer and a first amplification factor of the amplification of the focus gain adjustment unit, and the second gain Is a second frequency characteristic in which the gain of each frequency band is smaller than the first frequency characteristic of the focus equalizer, and a second gain smaller than the first gain of the amplification of the focus gain adjustment unit, An optical disc reproducing device characterized by the above. An optical disk reproducing apparatus according to claim 4 or 5, wherein
The optical disk reproducing apparatus, wherein the head amplifier amplifies the focus error signal at an amplification factor according to the amplitude of an RF signal generated from an output signal of a pickup. An automatic preparation method for an optical disk reproduction apparatus for automatically adjusting tracking servo characteristics in an optical disk reproduction apparatus for reproducing an optical disk,
A first step of setting a gain of a head amplifier that amplifies a tracking error signal generated based on an output signal of the pickup;
A second step of automatically adjusting a gain of tracking control according to the tracking error signal of the tracking control unit that performs tracking control according to the tracking error signal amplified by the head amplifier so as to obtain a desired tracking servo characteristic; Have
In the second step, when the level of the tracking error signal amplified by the head amplifier is not higher than a predetermined level, the automatic adjustment is started using the first gain as the gain at the start of the automatic adjustment, and the head amplifier When the level of the tracking error signal amplified by is increased by a predetermined level or more, the automatic adjustment is started using a second gain smaller than the first gain as a gain at the start of the automatic adjustment. Automatic adjustment method for equipment. An automatic preparation method for an optical disk reproduction apparatus for automatically adjusting focus servo characteristics in an optical disk reproduction apparatus for reproducing an optical disk,
A first step of setting a gain of a head amplifier that amplifies a focus error signal generated based on an output signal of the pickup;
A second step of automatically adjusting a gain of focus control according to the focus error signal of the focus control unit that performs focus control according to the focus error signal amplified by the head amplifier so as to obtain a desired focus servo characteristic; Have
In the second step, when the level of the focus error signal amplified by the head amplifier is not greater than a predetermined level, the automatic adjustment is started using the first gain as the gain at the start of the automatic adjustment, and the head amplifier When the level of the focus error signal amplified by is higher than a predetermined level, the automatic adjustment is started by using the second gain smaller than the first gain as the gain at the start of the automatic adjustment. Automatic adjustment method for equipment.