JP4547370B2 - Optical disk device - Google Patents

Description

  The present invention relates to an optical disc apparatus.

  As background art in this technical field, for example, there is JP-A-2002-251728. This publication describes that “the peak value of the tracking error TE signal is compared with a reference threshold value to determine whether the laser beam is irradiating the defect portion on the optical disk”.

  Further, as background art in this technical field, for example, there is JP-A-8-30987. This publication states that “by comparing the RF signal and its low-frequency component, the defect signal is output accurately without responding to fluctuations due to surface fluctuations or reflectance fluctuations of the RF signal”.

  As background art in this technical field, for example, there is JP-A-7-320283. In this publication, “FE signal is subjected to waveform processing by filter means 9b such as phase correction and low-frequency boost necessary for focus servo, and then ACT is driven by ACT drive amplifier 10b, and the light spot is focus-controlled on the disk surface. Similarly, the TE signal is subjected to waveform processing by the filter means 9a such as phase correction and low-frequency boost required for tracking servo, and then the tracking ACT is driven by the ACT drive amplifier 10a, and the light spot is phase-determined on the information track. There is a description.

  As background art in this technical field, there is, for example, JP-A-11-161958. In this publication, “the comparison signal Sfc generated at the same timing before at least one rotation is used to complement the comparison signal Sfc during the signal damage period stepwise, and the reference reproduction clock signal is used by the comparison signal Sfc after the complementation. "Ss is generated and reproduced".

  As background art in this technical field, for example, there is JP-A-2001-307347. In this publication, “a fluctuation amount calculation unit that calculates the fluctuation amount by comparing the integral value of the rotation angle section in which the dropout has occurred with the stored integral value in the same rotation angle section before the occurrence of the dropout, The equalizer equalization characteristics are changed according to the amount ".

JP 2002-251728 A JP-A-8-30987 JP-A-7-320283 JP-A-11-161958 JP 2001-307347 A

  In an optical disk, an objective lens is moved by a focus actuator and a tracking actuator so that a light spot follows a predetermined track of a predetermined recording / reproducing layer. The focus actuator and the tracking actuator are controlled by feedback based on an error signal generated using laser light reflected from the disk.

  On the other hand, the disk may have defects such as recording surface and track distortion, scratches on the disk surface, dust and dirt created during manufacture. Since these defects affect the focus or tracking error signal, the follow-up performance of the focus or track decreases when the light spot passes through the defect.

  As a method for detecting these defects, there are Patent Document 1 that compares the peak value of an error signal with a predetermined threshold value and Patent Document 2 that detects a defect by comparing a high-frequency component of the error signal with a predetermined threshold value.

  Further, as a countermeasure method for the detected defect, Patent Document 3 for switching the actuator control gain, Patent Document 4 for complementing the error signal in the defect using the error signal before one rotation, and the error at the same rotation angle before one rotation. There is Patent Document 5 in which a change amount of an integrated value of a signal is measured and a control characteristic is changed according to the change amount, or complemented using an error signal and a drive signal before one rotation.

  As described above, the method of detecting a defect using an error signal and changing the control characteristics of the focus actuator or the track actuator, or performing the complementary operation using the error signal or drive signal before one rotation is used when the defect passes. It is possible to reduce the deterioration of the focus or track following performance and to ensure the reliability of the device against the defect.

  However, there are various types of defects, and how to deal with them varies depending on the defect. For example, there are methods of holding the control signal and changing the control gain as methods for preventing the focus or track following performance from deteriorating when passing the defect. However, there are cases where the effect is adversely affected depending on the type of the defect. Further, even when there is an effect, the tracking error is reduced due to a change in the control method, so that there is a problem that the defect detection sensitivity is different and an appropriate timing for returning the control method to the original is unknown.

  As described above, in order to prevent an increase in the tracking error due to the defect, it is necessary to appropriately detect the defect, appropriately select a control method for the detected defect, and end the selected control method at an appropriate timing. If these processes cannot be performed properly, there arises a problem that the reliability of the apparatus is impaired.

  An object of the present invention is to provide an optical disc apparatus having high reliability even for discs having various defects.

  The above object can be achieved by, for example, the configuration described in the claims.

  According to the present invention, it is possible to provide a highly reliable optical disk apparatus for a disk having various defects.

  Examples will be described below. Each embodiment can be used in appropriate combination.

  First, the configuration of the first embodiment of the present invention will be described with reference to FIG.

  In FIG. 1, 1 is a disc, 2 is an objective lens, 3 is a focus actuator that drives the objective lens in the direction of the rotation axis of the disc, 4 is a tracking actuator that drives the objective lens in the radial direction of the disc, and 5 includes an objective lens. An optical pickup unit, 6 is a seek motor that drives the optical pickup unit in the radial direction of the disk, 7 is a photodetector, 8 is a focus error signal generating means for generating an error signal in the focus direction between the disk and the objective lens, and 9 is a light beam. Focus control signal generating means for controlling the focus actuator so as to position the spot on the disk recording surface or reproducing surface, 10 is a focus actuator driving means for driving the focus actuator, and 11 is an error signal in the tracking direction between the track of the disk and the objective lens. Tracking error signal generating means for generating a tracking error signal, 12 a tracking control signal generating means for controlling the tracking actuator to position the light spot on a predetermined track of the disk, 13 a tracking actuator driving means for driving the tracking actuator, and 14 a seek motor. A seek motor control means for controlling, 15 a seek motor drive means for driving the seek motor, 16 a spindle motor for rotating the disk, 17 a frequency generating means for generating a signal corresponding to the rotational speed of the spindle motor, and 18 a spindle motor Is a motor control means for controlling the motor to rotate at a predetermined speed, 19 is a frequency divider, 20 is a defect detection means, 21 is a memory, and 22 is a system control means.

  Next, an outline of the operation of each block and the relationship between the blocks will be described.

  In FIG. 1, the focus actuator 3 moves the objective lens 2 in the disc rotation axis direction, and the tracking actuator 4 moves the objective lens 2 in the disc radial direction. The seek motor 6 moves the optical pickup unit 5 in the disk radial direction. The photodetector 7 converts the reflected light into an electrical signal, and sends the converted signal to the focus error signal generation means 8, the tracking error signal detection means 11, and the system control means 22.

  The focus error signal generation unit 8 generates a focus error signal based on the signal sent from the photodetector 7, and sends the generated signal to the focus control signal generation unit 9 and the defect detection unit 20. The focus control signal generation means 9 generates a focus control signal based on the signal sent from the focus error signal generation means 8 and sends the generated signal to the focus actuator drive means 10, as well as the defect detection means 20, the memory 21, and the later-described. The control method is switched based on the signals sent from the frequency divider 19 and the system control means 22, and control information is sent to the defect detection means 20. The focus actuator driving means 10 drives the focus actuator 3 based on the signal sent from the focus control signal generating means 9.

  The tracking error signal generation unit 11 generates a tracking error signal based on the signal sent from the photodetector 7 and sends the generated signal to the tracking control signal generation unit 12 and the defect detection unit 20. The tracking control signal generating means 12 generates a tracking control signal based on the signal sent from the tracking error signal generating means 11, sends the generated signal to the tracking actuator driving means 13 and the seek motor control means 14, and detects the defect. The control method is switched based on signals sent from the means 20, the memory 21, a frequency divider 19, which will be described later, and the system control means 22, and control information is sent to the defect detection means 20. The tracking actuator driving unit 13 drives the tracking actuator 4 based on the signal sent from the tracking control signal generating unit 12.

  The seek motor control means 14 generates a seek motor control signal based on the signal sent from the tracking control signal generation means 12, and sends the generated signal to the seek motor drive means 15. The seek motor drive means 15 drives the seek motor 6 based on the signal sent from the seek motor control means 14. The spindle motor 16 drives the disk 1. The frequency generation means 17 converts the rotational speed information of the spindle motor 16 into an electrical signal, and sends the converted signal to the motor control means 18 and the frequency divider 19. The motor control means 18 controls the disk motor 16 so that the disk 1 rotates at a predetermined rotational speed based on the transmitted signal. Based on the signal sent from the light detector 7, the system control means 22 calculates the radial position information on the disk irradiated with the light spot from the physical address of the disk, and uses the calculated information as the focus detection means 20 and the focus detection information. The control signal generation means 9, the tracking control signal generation means 12 and the frequency divider 19 are sent. The frequency divider 19 divides the period of the signal sent from the frequency generating means 17 and the system control means 22 by an integer according to the radius, and the divided signal is generated by the defect detection means 20 and the focus control signal. The data is sent to the means 9 and the tracking control signal generating means 12. Here, the reason why the frequency division ratio is changed according to the radius is that the tracking distance of the light spot with respect to the frequency division section is unified at the inner and outer circumferences of the disc.

  The defect detection means 20 detects a defect on the disk based on signals sent from the focus error signal generation means 8, the tracking error signal detection means 11 and the frequency divider 19, and the detected defect information is used as focus control signal generation means. 9 and the tracking control signal generation means 12 and control information for changing the defect detection threshold is obtained from the focus control signal generation means 9 and the tracking control signal generation means 12. Further, the defect detection means 20 sends defect information including rotation angle information, radius information sent from the system control means 22, changed control information and threshold information to the memory 21. The memory 21 stores information sent from the defect detection means 20, and the focus control signal generation means 9 and the tracking control signal generation means 12 switch the processing method at the time of passing the defect from the information recorded in the memory 21.

  Here, before describing the detailed operation of each main block, the defect and the influence of the defect on the error signal will be briefly described. The defect on the disk usually extends over a plurality of tracks as shown in FIG. Accordingly, when the track is continuously followed from the inner periphery side of the defect, the focus error signal or the track error signal gradually increases as shown in FIG. 3, and when the track is further followed, the outer periphery side of the defect is gradually decreased. This defect is detected at an early stage, and a control method that prevents an increase in the error signal is judged appropriately, and the control method is stabilized by detecting that the influence of the defect has disappeared and returning the control method to the normal state at an appropriate timing. Realize control performance.

  Next, operations of the defect detection unit 20, the focus control signal generation unit 9, and the memory 21 which are main blocks of the present invention will be described with reference to FIG. The defect detection means 20 sends the signal sent from the focus error signal generation means 8 to the comparator 201. As shown in FIG. 5, each of the comparators 201 compares a predetermined threshold value ± Vth with the amplitude level of the focus error signal, and sends comparison information to the defect signal generation unit 203. The defect signal generation unit 203 measures a period in which the amplitude level of the focus error signal exceeds the threshold ± Vth from the comparison information sent from the comparator 201, and generates defect information as a defect signal when the measured period is equal to or greater than the threshold Tth. Send to means 211. The defect information generation unit 211 detects the presence / absence of a defect based on the information sent from the defect signal generation unit 203 and sends the detected defect information to the focus control signal generation unit 9.

  After detecting the defect, the focus control signal generating means 9 measures the peak level Fe0 of the focus error signal when the defect passes at the next same rotation angle. The focus control signal generation means 9 increases the control band at the next same rotation angle, and measures the peak level Fe1 of the focus error signal when passing the defect. The focus control signal generation means 9 further lowers the control band at the next same rotation angle, and measures the peak level Fe2 of the focus error signal when the defect passes. Next, the focus control signal generation means 9 compares Fe1 and Fe2, selects a control band in which the peak level is small, and calculates a ratio between the peak level in the selected band and the peak level of Fe0. The focus control signal generation means 9 sends the selection result, the calculated peak ratio, and the timing signal for switching to the selected control band to the defect detection means 20 as focus control information.

  Based on the peak ratio information and the control band switching timing signal, the defect detection means 20 changes the threshold value ± Vth of the comparator 201 at the timing when the control band is switched when the defect passes, and the defect signal generation means 203 detects at the same timing. The time threshold value Tth is changed. These operations are shown in FIG. The focus control signal generation means 9 switches to the control band selected by the detected defect rotation angle. The error signal in this section is reduced to + Vp ′ with respect to the level + Vp before switching the control band. Therefore, in the same section, the defect detection sensitivity becomes high unless the threshold value Vth of the comparator and the detection time + Tth are changed. Therefore, by changing the comparator threshold Vth and detection time + Tth to Vth ′ and Tth ′, respectively, corresponding to the peak level ratio + Vp ′ / + Vp, the defect is monitored under the same conditions as before the control band change. In other words, it is appropriately determined to end the control band switching operation in the same section. The defect processing operation for tracking is omitted because it is the same as the focus.

  Finally, information stored in the memory 21 will be described with reference to FIG. “Tr / Af” indicates whether the defect is detected from a focus error signal or a tracking error signal. The radius information indicates the radius when the defect is detected. The radius information uses mm as a unit, but the present invention is not limited to this, and the same effect can be obtained by using the address information of the disk or the movement distance of the seek motor as the radius information. Further, the detected rotation angle of the defect may fall within one pulse of the divided FG or may extend to a plurality of pulses, and FIG. 7 shows them. Further, the control band changed in the detection section, the changed comparator threshold value, and the detection time are stored. When the end of the defect is detected, the defect end radius is recorded. The memory 21 information is used when the track having the detected defect is followed again. When radius information of the outer peripheral edge of the defect is stored, the control band is changed between “detection radius” and “radius (end)” in FIG. This occurs when the defect detection is performed when the radius information of the outer peripheral edge of the defect is not stored, but cannot be detected by a seek operation or the like before the radius of the outer peripheral edge of the defect is detected. In this case, the comparator and the detection time threshold are switched based on the values stored in “threshold 1” and “threshold 2”, and the control band is continuously switched until the radius of the outer peripheral edge is detected.

  As described above, the defect is detected from the focus and tracking error signals, the control band in which the error signal level is reduced is measured, the control band is switched in the rotation angle section of the detected defect, and the control band is changed. By switching the comparator threshold value and detection time width for defect detection within the same interval based on the reduction amount of the error signal level, it is possible to improve the tracking performance of focus and tracking for the defect.

  Next, a second embodiment of the present invention will be described with reference to FIGS.

  The configuration of the block diagram is the same as that of FIG.

  An outline of the operation of each block and the relationship between the blocks will be described.

  In FIG. 1, the focus control signal generation means 9 generates a focus control signal based on the signal sent from the focus error signal generation means 8, sends the generated signal to the focus actuator drive means 10, and the defect detection means 20 The control method is switched based on signals sent from the memory 21, a frequency divider 19 described later, and the system control means 22, and control information is sent to the defect detection means 20. The tracking control signal generating means 12 generates a tracking control signal based on the signal sent from the tracking error signal generating means 11, sends the generated signal to the tracking actuator driving means 13 and the seek motor control means 14, and detects the defect. The control method is switched based on signals sent from the means 20, the memory 21, a frequency divider 19, which will be described later, and the system control means 22, and control information is sent to the defect detection means 20. The defect detection means 20 detects a defect on the disk based on signals sent from the focus error signal generation means 8, the tracking error signal detection means 11 and the frequency divider 19, and identifies the detected defect using a filter. Then, the detected defect information is sent to the focus control signal generation means 9 and the tracking control signal generation means 12. Further, control information for changing the defect detection threshold is obtained from the focus control signal generation means 9 and the tracking control signal generation means 12. Further, the defect detection means 20 sends defect information including defect identification information, rotation angle information, radius information sent from the system control means 22, changed control information and threshold information to the memory 21. Other block-to-block operations are the same as those in the first embodiment, and will be omitted.

  Next, operations of the defect detection unit 20, the focus control signal generation unit 9, and the memory 21 which are main blocks of the present invention will be described with reference to FIG. The defect detection means 20 sends the signals sent from the focus error signal generation means 8 to the comparator 201 and the high-pass filter 205, respectively. The comparator 201 compares the predetermined threshold value ± Vth with the amplitude level of the focus error signal and sends the comparison information to the defect signal generation means 203 as in FIG. The defect signal generation means 203 measures the period when the amplitude level of the focus error signal exceeds the threshold value ± Vth from the comparison information sent from the comparator 201, and when the measured period is equal to or greater than the threshold value Tth, It is sent to the defect information generation means 211. On the other hand, the high pass filter 205 extracts a high frequency component of the focus error signal and sends it to the comparator 207. Here, the cut-off frequency fc of the high-pass filter 205 is equal to or lower than the control band fs for focus control, and is set to detect at least a signal equal to or higher than the control band fs. Similar to the comparator 201, the comparator 207 compares the predetermined threshold value ± Vth with the amplitude level of the output signal from the high-pass filter 205, and sends the comparison result to the defect type information generation means 209. The defect type information generation unit 209 measures the period when the amplitude level of the output signal from the comparator 207 exceeds the threshold value ± Vth similarly to the defect signal generation unit 203, and when the measured period is equal to or higher than the threshold value Tth, The defect signal is sent to the defect information generation means 211 as a defect signal. The defect information generation means 211 identifies whether the detected defect is detected as a high-frequency focus error signal or a low-frequency signal, generates defect identification information, and generates the generated defect identification information as a focus control signal. Send to means 9.

  The focus control signal generation means 9 first measures the peak level Fe0 of the focus error signal when passing the defect at the next same rotation angle after detecting the defect. Further, the focus control frequency band is switched based on the defect identification information at the next same rotation angle. At this time, the control band is lowered when a high-frequency focus error signal is detected by the detected defect, and the frequency characteristic band is raised when a low-frequency focus error signal is detected. FIG. 9 schematically shows the operation timing and the influence on the focus error signal when the frequency characteristic band is lowered. The dotted line of the focus error signal is a waveform before the band is lowered, and the error signal level is large due to the overresponse of the control system after passing the defect. By reducing the frequency characteristic band when passing the defect, it is possible to prevent an over-response of the control system as shown by a solid line and to reduce the error signal level after passing the defect. FIG. 10 schematically shows the operation timing and the influence on the focus error signal when the frequency characteristic band is increased. When a focus error signal having a low frequency such as a dotted line is generated, the cause is often disk distortion or the like. In this case, by increasing the frequency characteristic band when passing the defect, the tracking error due to distortion can be suppressed as shown by the solid line, and the error signal level can be reduced. The focus control signal generating means 9 switches the band and measures the peak level Fe3 of the focus error signal when passing through the defect, calculates the peak level ratio of Fe0 and Fe3, and selects the calculated peak level ratio. A timing signal for switching to the control band is sent to the defect detection means 20 as focus control information.

  Based on the peak ratio information and the control band switching timing signal, the defect detection means 20 changes the threshold values ± Vth of the comparators 201 and 207 at the timing when the control band is switched when the defect passes, and the defect signal generation means 203 at the same timing. The detection time threshold value Tth of the defect type information generation means 209 is changed. The defect processing operation for tracking is omitted because it is the same as the focus.

  Finally, information stored in the memory 21 will be described with reference to FIG. The identification column is “Hi” when a high-frequency focus error signal or tracking error signal is detected by the detected defect, and “Lo” when a low-frequency focus error signal or tracking error signal is detected. Other items such as “Tr / Af” are the same as those in the first embodiment, and are omitted.

  In this embodiment, a high-pass filter is used as a method for identifying a defect. However, as shown in FIG. 12, it is possible to identify a defect by using two threshold values ± Vth1, ± Vth2 and a detection time setting Tth for the focus and tracking error signals. It is. That is, by detecting the presence / absence of a defect with the threshold value ± Vth1, and measuring the time when the error signal at this time exceeds ± Vth2, the defect can be identified based on the measured time. In this case, the configuration of the defect detection means 20 is the configuration shown in FIG. 4, and the comparators 201 and 202 have two threshold values.

  In this embodiment, when a high-frequency focus error signal or tracking error signal is detected due to a defect, the operation is performed to lower the frequency characteristic band. However, the present invention is not limited to this. Even if the focus control signal or tracking control signal is held during the defect passing period, the effect can be obtained.

  As described above, the defect is detected and identified from the focus and tracking error signals, and the control band is switched in the rotation angle section of the detected defect so that the error signal level becomes small, and the error signal due to the change of the control band By switching the comparator threshold value and detection time width for defect detection within the same interval based on the level reduction amount, it is possible to improve the tracking performance of focus and tracking for the defect.

Components explanatory diagram of this embodiment Defect explanatory diagram Explanation of error signal when defect passes Component explanatory drawing of the defect detection means of Example 1 Explanation of operation of defect detection means 1 Explanatory diagram of operation when defect detection means passes defect Storage contents explanatory diagram of the memory of Example 1 Component explanatory drawing of the defect detection means of Example 2 FIG. 1 is a diagram for explaining the operation of the focus control signal generating means when passing a defect. FIG. 2 is a diagram for explaining the operation of the focus control signal generating means when passing the defect. Explanation of contents stored in memory of embodiment 2 Explanation of operation of defect detection means FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Disk, 2 ... Objective lens, 3 ... Focus actuator, 4 ... Tracking actuator, 5 ... Optical pick-up unit, 6 ... Seek motor, 7 ... Photo detector, 8: Focus error signal generating means, 9: Focus control signal generating means, 10: Focus actuator driving means, 11: Tracking error signal generating means, 12: Tracking control signal generating means, 13 ... Tracking actuator driving means, 14 ... seek motor control means, 15 ... seek motor driving means, 16 ... spindle motor, 17 ... frequency generating means, 18 ... motor control means, 19 ... Frequency divider, 20 ... Defect detection means, 21 ... Memory, 22 ... System control means.

Claims (6)

An optical disk device capable of mounting an optical disk,
A laser light source for emitting laser light;
An objective lens for condensing the laser light from the laser light source on a disk;
A focus actuator for moving the objective lens in the disc rotation axis direction;
A tracking actuator that moves the objective lens in the radial direction of the disk;
A detector that converts the reflected light from the disk into an electrical signal;
A focus error signal generating means for generating a focus error signal based on an output from the detector;
Tracking error signal generating means for generating a tracking error signal based on an output from the detector;
Focus actuator control means for controlling the focus actuator;
Tracking actuator control means for controlling the tracking actuator;
Defect detection means f for detecting a defect on the disk based on the output of the focus error signal generation means;
Defect detection means t for detecting a defect on the disk based on the output of the tracking error signal generation means;
A disk motor that rotates the disk;
Disk motor control means for controlling the disk motor;
A rotation angle detection means for detecting a rotation phase of the disk motor;
Have
Based on the output of the defect detection means f and the output of the rotation angle detection means, the focus actuator control means changes the frequency characteristics between the rotation angle at which the defect is detected and other rotation angles, and further, the defect detection The means f measures the output signal level F of the focus error signal generation means when the frequency characteristic of the focus actuator control means is changed, and the rotation angle at which the defect is detected based on the detected output signal level F and the others Change the defect detection sensitivity with the rotation angle of
Based on the output of the defect detection means t and the output of the rotation angle detection means, the tracking actuator control means changes the frequency characteristics between the rotation angle at which the defect is detected and other rotation angles, and further, the defect detection The means t measures the output signal level T of the tracking error signal generation means when the frequency characteristic of the tracking actuator control means is changed, and the rotation angle at which the defect is detected based on the detected output signal level T and the others Change the defect detection sensitivity with the rotation angle of
An optical disc device characterized by the above. The optical disc apparatus according to claim 1 ,
Radius detecting means for detecting the disk radial position of the track followed by the light spot;
Have
The rotation angle detection means divides an FG (Frequency Generator) synchronized with the rotation speed of the disk motor, and detects the rotation angle of the disk motor by changing the frequency division ratio according to the output of the radius detection means. To
An optical disc device characterized by the above. The apparatus according to claim 1 or 2,
The focus actuator control means changes the frequency characteristic to the characteristic f1 at the same rotation angle after one rotation of the disk at the rotation angle at which the defect is detected based on the output of the defect detection means f and the output of the rotation angle detection means. At the same time, the first focus tracking error at the time of characteristic change is detected,
Further, the frequency characteristic is changed to the characteristic f2 at the same rotation angle after one rotation of the disk, and the second focus tracking error is detected.
From the comparison result of the measured first focus tracking error and second focus tracking error,
Reselect the frequency characteristics of the focus control,
The tracking actuator control means changes the frequency characteristic to the characteristic t1 at the same rotation angle after one rotation of the disk at the rotation angle at which the defect is detected based on the output of the defect detection means t and the output of the rotation angle detection means. At the same time, the first tracking tracking error at the time of characteristic change is detected,
Further, the frequency characteristic is changed to the characteristic t2 at the same rotation angle after one rotation of the disk, and the second tracking tracking error is detected.
Re-selecting the tracking frequency characteristic from the comparison result of the measured first tracking tracking error and the second tracking tracking error;
An optical disc device characterized by the above. The apparatus according to claim 1 or 2,
The defect detection means f has a high-pass filter Hf having a cutoff frequency fc (f) below the control band fs (f) of focus control,
Based on the output of the focus error signal generating means and the output of the high pass filter Hf, the detected defect is identified,
If the output of the focus error signal generation means is a high frequency, lower the control band of the focus actuator control means,
If the output of the focus error signal generation means is a low frequency, increase the control band of the focus actuator control means,
The defect detection means t includes a high-pass filter Ht having a cutoff frequency fc (t) that is equal to or less than a control band fs (t) for tracking control.
Based on the output of the tracking error signal generating means and the output of the high pass filter Ht, the detected defect is identified,
When the output of the tracking error signal generating means is a frequency higher than the band of the high pass filter Ht, the control band of the tracking actuator control means is lowered,
When the output of the tracking error signal generating means is a frequency lower than the band of the high pass filter Ht, the control band of the tracking actuator control means is increased.
An optical disc device characterized by the above. The apparatus according to claim 1 or 2,
The defect detection means f has two comparison values Cf1 and Cf2 (<comparison value Cf1) for comparing the outputs of the focus error signal generation means,
A defect is detected by comparing the output of the focus error signal generating means with a comparison value Cf1,
Measuring the time when the output level of the focus error signal generating means is larger than the comparison value Cf2 at the time of detecting the defect;
If the measured time is shorter than a predetermined value, lower the control band of the focus actuator control means,
If the measured time is longer than a predetermined value, increase the control band of the focus actuator control means,
The defect detection means t has two comparison values Ct1 and a comparison value Ct2 (<comparison value Ct1) for comparing the outputs of the tracking error signal generation means,
A defect is detected by comparing the output of the tracking error signal generating means with a comparison value Ct1;
Measuring the time when the output level of the tracking error signal generating means is larger than the comparison value Ct2 at the time of detecting the defect;
If the measured time is shorter than a predetermined value, lower the control band of the tracking actuator control means,
If the measured time is longer than a predetermined value, increase the control band of the tracking actuator control means,
An optical disc device characterized by the above. An optical disc apparatus according to any one of claims 2 to 5 ,
A memory for storing defect information;
A defect detection means for detecting a defect, a rotation angle of the detected defect, a disk radius range in which the detected defect exists, and a changed frequency characteristic;
The focus actuator control means and the tracking actuator control means, based on the memory means, have a frequency characteristic with a stored phase angle and other phase angles when the light spot follows a track in which a defect has been detected in the past. change,
An optical disc device characterized by the above.

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