JP2001118271A - Surface wobble correction and control method, eccentricity correction and control method, and optical disk device using them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively realize a surface wobble and eccentricity correction control provided with high operability by repeatedly using a surface wobble correction signal and an eccentricity correction signal generated after a disk is loaded until the disk is exchanged or re-loaded in the next time and eliminating re-detection even when the disk stops. SOLUTION: A signal synchronized with the rotational frequency of an optical disk is identified based on the rotational phase information of the optical disk, and the surface wobble and eccentricity correction data are generated to be preserved, and by outputting the preserved surface wobble correction data based on the signal synchronized with the rotational frequency, the surface wobble is corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method for detecting and correcting surface deviation and eccentricity of a disk during recording or reproduction of the disk, and to an optical disk apparatus using these methods.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. H10-21571 discloses a known example of a disk device which detects a disk rotation component of a tracking error signal and a focus error signal and corrects eccentricity and runout of a disk or the like.

The basic methods of the conventional eccentricity correction and surface blur correction are as follows. First, the tracking and focus error signal levels synchronized with the output of the frequency generator of the disk motor (hereinafter referred to as FG: Frequency Generator) are detected, and the rotational frequency component and its harmonic components of each detected signal are detected. obtain. A correction signal for eccentricity and runout is generated from each of the obtained error signals, and each of the actuators is driven in accordance with a feedback control signal for tracking and focus. Since each actuator operates to absorb the eccentricity and the runout by the correction signal, the tracking error of the track and the focus is reduced, and as a result, a high-precision control system is formed and the reliability of the disk device can be improved.

[0004]

The method of obtaining the rotational frequency component and its harmonic component of each of the tracking and focus error signals can be roughly classified into two methods. One is a method of detecting an error signal level synchronized with the FG every time the disk rotates, and adding it as a control signal of each actuator after one rotation. According to this method, the error signal level of each FG is always detected while the disk is rotating, so that the runout and eccentricity can be corrected with high accuracy, but a huge amount of processing is required, and the processing is performed in parallel with the recording operation and the reproducing operation. It is difficult to do. The other is a method of repeatedly using an error signal level detected once. This is because the amount of runout and the amount of eccentricity largely depend on the used disk and the installation state of the spindle motor, and the error signal level once detected is considered to be substantially equal until the disk is replaced or remounted.

A problem with the latter method of repeatedly using the detected error signal level is that it is necessary to identify a plurality of FGs generated plural times in one rotation of the disk. A focus error signal and a tracking error signal detected at a certain FG generation timing need to be output as correction signals at the same FG generation timing even during correction. Usually, the FG signal is simply
Since it is a Lo / Hi signal, it is difficult to identify each FG only by the waveform.

As a simple method of identifying each FG, it is conceivable to always count FGs from the start of detection of an error signal. However, if the disk stops or the rotation frequency drops extremely, the disk rotation period and FG
Since the FG itself becomes unstable, it is difficult to identify the FG by counting.

Further, if the correction signal is cleared each time the disk stops rotating and an error signal is detected again when the disk is started, the start-up time of the apparatus is delayed. In recent years, intermittent drive of the device is often performed as one of means for realizing low power of the device, and the start and stop of the disk are performed frequently, so the start time delay is a serious problem that lowers operability. Disadvantages.

Further, if there is an erroneous count due to noise even while the disk is rotating, a correction signal is added with a deviation from the timing to be actually added, and the correction effect is reduced or disturbance occurs.

An object of the present invention is to repeatedly use a surface shake correction signal and an eccentricity correction signal generated after mounting a disk until the next disk replacement or reloading, so that redetection is unnecessary even if the disk stops. Accordingly, it is an object to realize inexpensive realization of eccentricity correction control with high operability.

[0010] Another object of the present invention is to realize a highly reliable surface deviation and eccentricity correction control capable of promptly detecting and correcting erroneous counting of FG due to noise or the like by periodically performing FG discriminating operation, and at low cost. .

[0011]

In order to attain the object of the present invention, a method for controlling a surface shake correction according to the present invention generates a signal synchronized with a rotation frequency of the optical disk and detects rotation phase information of the optical disk. Using a signal synchronized with the rotation frequency, the rotation phase information, and a focus control signal generated for focusing light on the optical disc, generate and save surface shake correction data, The apparatus is characterized in that the shake is corrected by outputting the stored shake correction data based on a signal synchronized with the frequency. In addition, the surface shake correction data is generated based on the rotational frequency component and the harmonic component of the focus control signal, and is generated based on the detected rotational frequency component and the harmonic component of the focus control signal. Further, after the optical disk is mounted, eccentricity correction data is generated and stored, and the stored correction data is used until the optical disk is detached.

An optical disk apparatus according to the present invention has an objective lens and a focus actuator for driving the objective lens, a pickup for recording information on the disk or reproducing the recorded information, and a drive for rotating the disk. Means, frequency generation means for generating a frequency obtained based on the rotation speed of the disk, focus error signal detection means for detecting a focus error signal obtained from the disk via the pickup,
Focus control signal generating means for generating a focus control signal for the objective lens to focus on the disk based on the output of the focus error signal detecting means, focus actuator driving means for driving the focus actuator, Rotation phase information detection means for detecting rotation phase information of the disk obtained via the pickup, and FG for identifying an output (FG) of the frequency generation means based on the rotation phase information
Identification means; plane shake correction signal generation means for generating a plane shake correction signal based on the focus control signal and the FG; memory means for storing the plane shake correction signal as plane shake correction data; Memory control means for controlling the output of the image stabilization data from the memory means based on

As the rotation phase information, a land / groove signal for identifying whether a track on the optical disk is a land or a groove, and address information recorded on the disk are used.

[0014] Further, the surface shake correction signal generating means detects a component of the focus control signal based on a signal for discriminating disc attachment / detachment. Component detection of the focus control signal obtained when following up may be performed.

[0015] Further, the memory control means, when starting the image stabilization, outputs the correction data which is closest to the average value of all the correction data stored in the memory means. Is controlled.

[0016] The memory control means may further include information on a disk radius at a position on the disk that the objective lens follows when detecting the component of the focus control signal, and a known frequency characteristic of the focus actuator. On the basis of this, correction data is generated for each disk radius and stored in the memory.

Further, the eccentricity correction control method of the present invention and the optical disk apparatus using the same are realized by using a tracking control signal instead of the focus control signal in the above-described surface shake correction control method and the optical disk apparatus using the same. You.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG.

First, a description will be given of a control system for correcting a runout and an eccentricity of the present invention and a configuration of an optical disk apparatus using the same.

1 is a tracking actuator, 2 is a focus actuator, 3 is a pickup, 4 is a disk, 5 is a disk drive means, 6 is a disk rotation frequency generation means, 7 is a disk rotation control means, 8 is a focus error signal detection means, 9 is a focus control signal generating means, 10 is a focus switching means, 11 is a focus adder, 12 is a system control means, 13 is an FG identification means, 14 is a plane blur correction signal generating section, and 15 is a memory for plane blur correction data. , 16 are the memory control means for the runout, 1
Numeral 7 denotes a surface shake correction signal DC removing means, numeral 18 denotes a focus drive signal generating means, numeral 19 denotes a tracking error signal detecting means, numeral 20 denotes a tracking control signal generating means, numeral 21 denotes a tracking switching means, numeral 22 denotes a tracking adder, and numeral 23 denotes an eccentricity. A correction signal generation unit, 24 is an eccentricity correction data memory, 25 is an eccentricity memory control unit, 26 is an eccentricity correction signal DC removal unit, and 27 is a tracking drive signal generation unit.

Next, the relationship between the blocks of the spindle system will be described.

The disk drive means 5 rotates the disk 4 based on the output of the disk rotation control means 7. The disk rotation frequency generating means 6 is a signal synchronized with the rotation frequency of the disk 4 (hereinafter, referred to as FG: frequency generator signal).
To the disk rotation control means 6 and the FG identification means 13.

Next, the relationship between each block of the focus system will be described.

The focus actuator 2 moves the pickup 3 in the direction of the rotation axis of the disk 4, and positions the focused focal point on the disk surface. The reflected light from the disk 4 is sent to the focus error detecting means 8. The focus error detection means 8 detects the focus error amount, and sends the detected focus control signal to the focus control signal generation means 9. The focus control signal generating means 9 generates a focus control signal based on the focus error signal, and sends the generated focus error signal to the focus switching means 10. Focusing switching means 10
Selectively sends the focus control signal sent based on the external signal a1 and the focus open control signal other than the feedback control to the adder 11 for focus. The focus adder 11 is provided with the focus switching means 10.
Is added to the output of a plane blur correction signal DC removing unit 17 described later, and the added signal is sent to the plane blur correction signal generating unit 14 and the focus drive signal generating unit 18.

Next, the relationship between the respective blocks of the tracking system will be described.

The tracking actuator 1 moves the pickup 3 in the radial direction of the disk 4 so that the focused focal point is located on a track on the disk 4. Disc 4
The reflected light from is transmitted to the tracking error detecting means 19. The tracking error detection means 19 detects the tracking error amount and sends the detected tracking error signal to the tracking control signal generation means 20. The tracking control signal generating means 20 generates a tracking control signal based on the tracking error signal, and sends the generated tracking control signal to the tracking switching means 21. The tracking switching means 21 selectively sends the tracking control signal sent based on the external signal a2 and the tracking open control signal other than the feedback control to the tracking adder 22. The tracking adder 22 includes a tracking switching unit 21.
Is added to the output of the eccentricity correction signal DC removing means 26 described later, and the added signal is sent to the eccentricity correction signal generation means 23 and the tracking drive signal generation means 27.

Next, a method of identifying an FG signal according to the present invention will be described.

When the focus error signal and tracking error signal detected once are used as the surface eccentricity correction signal, the focus error signal and the tracking error signal are detected and stored in a memory using each FG as a trigger as shown in FIG. An operation is performed so as to output a correction signal at a timing when the FG is detected. Therefore, it is important to identify a plurality of FGs generated in one rotation of the disk.

In the present invention, in order to identify the FG, rotation phase information of the disk, that is, a signal generated for each rotation of the disk is used. As the rotation phase information, for example, FIG.
And a land and groove switching signal can be used. Once the disc is set, the phase relationship between the land / groove switching and the FG is determined, so that each FG can be identified by numbering the FG based on the switching. Alternatively, as shown in FIG. 3B, a physical address (black portion) recorded on the disk may be used as rotation phase information as a reference for FG identification. In this case, since the phase with the FG differs for each physical address, it is necessary to create a data table indicating the position of each physical address and the FG at the time of data detection.

Hereinafter, identification of the FG and generation of the correction data will be described with reference to FIGS.

The FG discriminating means 13 numbers the FG based on the land / groove signal sent from the system control means 12 and the FG sent from the disk rotation frequency generating means 6, and adds the numbering information to the sent FG to add the numbering information. Shake correction signal generation means 14, memory control means for surface shake, eccentricity correction signal generation means 23, and memory 24 for eccentricity correction data
Send to The shake correction signal generating means 14 is provided by the FG identifying means 13.
Then, a surface blur correction signal is generated based on the output of the focus adder 11 and the generated correction signal is sent to the surface blur correction data memory 15. Memory 1 for surface shake correction data
Reference numeral 5 stores the transmitted correction signal and outputs correction data in accordance with the memory control means 16 for surface deviation. The plane blur correction signal DC removing means 17 removes the DC component of the correction data sent, and sends the obtained DC removal signal to the adder 11 for focusing. Similarly, the eccentricity correction signal generation means 23 is the FG identification means 1
An eccentricity correction signal is generated based on the output of the tracking adder 22 and the output of the tracking adder 22, and the generated correction signal is sent to the eccentricity correction data memory 24. Eccentricity correction data memory 24
Saves the transmitted correction signal and stores the eccentricity memory control means 2
5, the correction data is output. The eccentricity correction signal DC removing means 26 removes the DC component of the sent correction data, and sends the obtained DC removal signal to the tracking adder 22.

Next, the detailed operation of the main blocks of the present invention will be described.

First, the system control means 12 detects whether the focused spot follows the land on the disk or follows the groove, and sends the detected signal to the FG identification means 13. The FG discriminating means 13 obtains a land / groove signal from the system control means 12 to detect a land-groove switching point shown in FIG. After detecting the switching point, FG1, F
In the order of G2...
Since the G signal is sent, these FGs are numbered. The FG discriminating means 13 adds a count number to the FG signal and sends it to the surface shake correction signal generating means 14 and the eccentricity correction signal generating means 23. The surface shake correction signal generation means 14 and the eccentricity correction signal generation means 23 detect the focus and tracking error signals, respectively, using the numbered FG as a trigger.

B1 and b2 in FIG.
And 23 are command signals for performing the above operation, which become Hi each time a disk is mounted, and become Lo when detection of each error signal is completed. Therefore, the signal generating means 14 and 23
Data detection is performed when 1 and b2 are Hi, and the detection operation is stopped when it is Lo.

The signal generating means 14 and 23 count the FG generation cycle sent from the FG discriminating means 13 by a high frequency clock. When the FG generation cycle becomes equal to or less than a predetermined value and the disk rotation speed becomes high, the above detection is performed. Start operation.

In the correction data stored in the memories 15 and 24, the numbered FGs and the focus and tracking error signals detected corresponding to each FG are stored in association with each other, and the output operation is controlled by the control means 16 and 25. Respectively controlled by The control means 16 and 25
After detecting and storing the correction data from the memory 1 and b2,
4 performs an output operation. The output is to output a correction value corresponding to each FG based on the number of the FG sent from the FG identifying means 13. The operation is started by the FG identification means 1
3 is counted by a high frequency clock, and the FG generation cycle is performed after the FG generation cycle becomes a predetermined value or less and the disk rotation speed becomes high.

Further, after storing the correction data, the control means 16 and 25 calculate the average value of the respective stored data, and detect the data and the FG number whose absolute value is closest to the calculated average value. This is to avoid a sudden change in the correction signal by starting output from data having a large correction value level as shown in FIG. The control means 16 and 25 control the memories 15 and 24 so as to start the correction output from the data closest to the average value.

In addition, the control means 16 and 25 control the position of the disk in which the error signal was detected in the radial direction and the memory 1
The correction data corresponding to the radial position at the time of performing the signal correction is calculated from the data stored in the memory 5, 24, and the memory 15,
Save to 24. This is because the gain differs depending on the operating frequency of the actuator due to the frequency characteristics of the actuator, and the CLV (constant linear speed spindle control) or ZCLV whose rotational speed varies depending on the radius of the track to follow
(Spindle control that keeps the linear velocity approximately constant for each zone)
In this case, the operation is necessary to keep the correction gain constant.

Further, a1 and a2 in FIG. 1 are switching commands for performing a focus, tracking feedback operation such as read, write, and following operations, and for performing an operation other than feedback such as a stop or sweep operation. .

As described above, the FG is numbered using the land / groove signal or the physical address and the like, so that the generated surface shake and eccentricity correction signals are output from the time of mounting the disk to the time of mounting or dismounting the disk regardless of the rotation or stop of the disk. Repeated use up to, with high operability
An eccentricity correction control device can be realized at low cost.

Also, as in the case of the FG identification means 13,
By performing the discrimination operation, erroneous counting of FG due to noise or the like can be quickly detected and corrected, so that highly reliable surface deviation and eccentricity correction control can be realized.

In the above embodiment, a method of correcting surface runout and eccentricity has been described for a disk having a single recording / reproducing surface, but the present invention is not limited to this. In the case of a disc having a plurality of recording / reproducing surfaces, for example, a two-layer disc, the runout eccentricity differs for each layer, and there is no correlation in size and phase. Therefore, the same effect can be obtained by performing detection for each layer and identifying the layer at the time of correction and outputting the corresponding correction data.

[0043]

As described above, according to the present invention, the initial object can be achieved. By numbering the FGs using the disk rotation phase information, the generated run-out and eccentricity correction signals are repeatedly used from the time the disk is mounted until the disk is replaced or re-mounted, regardless of the rotation or stop of the disk. In addition, it is possible to inexpensively realize the surface runout and eccentricity correction control with high operability.

Also, as in the case of the FG identifying means 13,
By performing the G identification operation, erroneous counting of FG due to noise or the like can be quickly detected and corrected, so that highly reliable surface deviation and eccentricity correction control can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optical disk device showing one embodiment of the present invention.

FIG. 2 is a diagram showing an embodiment of FG recognition according to the present invention.

FIG. 3 is a diagram illustrating disk rotation phase information according to the present invention.

FIG. 4 is a diagram showing one embodiment of correction data output in the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Tracking actuator, 2 ... Focus actuator, 6 ... Disk rotation frequency generation means, 8 ... Focus error signal detection means, 9 ...
Focus control signal generation means, 12: System control means, 13: FG identification means, 14: Image blur correction signal generation means, 15: Memory for image blur correction data,
16: memory control means for surface deviation, 18: focus drive signal generation means, 19: tracking error signal detection means, 20: tracking control signal generation means, 23: eccentricity correction signal generation means , 24 ... memory for eccentricity correction data, 25 ... memory control means for eccentricity.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Hiroaki Ono 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture F-term in the Digital Media Development Division, Hitachi, Ltd. 5D109 KA12 KB22 KD04 KD13 5D118 AA14 BA01 CB02 CD02 CD07 CD12 CD13

Claims (20)

[Claims] An optical disk drive for performing recording / reproduction of an optical disk while correcting optical disk surface deviation, comprising: generating a signal synchronized with a rotation frequency of the optical disk; Detecting information, using a signal synchronized with the rotation frequency, the rotation phase information, and a focus control signal generated for focusing light on the optical disk, generating and storing surface shake correction data. Then, based on a signal synchronized with the rotation frequency, the stored surface blur correction data is output to correct the surface blur, thereby controlling the surface blur correction. 2. A method for controlling a surface shake correction of an optical disk device for recording or reproducing an optical disk while correcting a surface shake of the optical disk, comprising: generating a signal synchronized with a rotation frequency of the optical disk; Detecting information, identifying a signal synchronized with the rotation frequency based on the rotation phase information, and based on the identified signal, a focus control signal generated for focusing light on the optical disc. A rotational frequency component and a harmonic component are detected, and based on the detected rotational frequency component and the harmonic component of the focus control signal, surface shake correction data is generated and stored, and based on a signal synchronized with the rotational frequency. And correcting the surface blur by outputting the stored surface blur correction data. 3. A pickup having an objective lens and a focus actuator for driving the objective lens, for recording information on the disk or reproducing the information recorded on the disk, driving means for rotating the disk, and the disk Frequency generating means for generating a frequency obtained based on the rotation speed of the disk, focus error signal detecting means for detecting a focus error signal obtained from the disk via the pickup, and based on an output of the focus error signal detecting means. A focus control signal generating means for generating a focus control signal for causing the objective lens to focus on the disk; a focus actuator driving means for driving the focus actuator; Rotational phase information Phase information detecting means for detecting the rotation phase information; FG identifying means for identifying the output (FG) of the frequency generating means based on the rotational phase information; and surface shake correction based on the focus control signal and the FG. A shake correction signal generating means for generating a signal; a memory means for storing the shake correction signal as shake correction data; and a memory for controlling output of the shake correction data from the memory means based on the FG. An optical disk device having a control unit. 4. The optical disk apparatus according to claim 3, wherein said plane deviation correction signal generation means detects a rotational frequency component of said disk and a harmonic component thereof of said focus control signal, thereby producing a plane deviation correction signal. An optical disc device for generating an optical disc. 5. The optical disk device according to claim 3, wherein the rotation phase information is a land / groove signal for identifying whether a track of the optical disk is a land or a groove. apparatus. 6. The optical disk device according to claim 3, wherein the rotation phase information is address information recorded on the disk. 7. An optical disk apparatus according to claim 4, wherein said surface shake correction signal generation means detects a component of said focus control signal based on a signal for identifying whether the disk is attached or detached. 8. The optical disk device according to claim 3, wherein said memory control means, when starting a surface shake correction, corrects a correction closest to an average value of all correction data stored in said memory means. An optical disk device, wherein the output of the memory means is controlled so as to output from data. 9. The optical disk device according to claim 3, wherein said memory control means includes information on a disk radius at a position on the disk that the objective lens followed when detecting a component of the focus control signal. An optical disk device that generates correction data for each disk radius based on a known frequency characteristic of the focus actuator and stores the correction data in the memory. 10. An optical disk apparatus according to claim 4, wherein said surface shake correction signal generating means detects a component of said focus control signal obtained when said objective lens follows substantially the outer periphery of said optical disk. An optical disc device characterized by the above-mentioned. 11. An eccentricity correction control method for an optical disk device for recording or reproducing an optical disk while correcting the eccentricity of the optical disk, comprising: generating a signal synchronized with a rotation frequency of the optical disk; Detected, using a signal synchronized with the rotation frequency, the rotation phase information, and a tracking control signal generated to cause the focus of light to follow a track on the optical disc,
An eccentricity correction control method comprising: generating and storing eccentricity correction data; and correcting the eccentricity by outputting the stored eccentricity correction data based on a signal synchronized with the rotation frequency. 12. An eccentricity correction control method for an optical disk apparatus for recording or reproducing an optical disk while correcting the eccentricity of the optical disk, comprising: generating a signal synchronized with a rotation frequency of the optical disk; Detecting, based on the rotational phase information, identifying a signal synchronized with the rotational frequency; and, based on the identified signal, a tracking control generated to cause a light track to follow a track on the optical disc. The rotational frequency component and the harmonic component of the signal are detected. Based on the rotational frequency component and the harmonic component of the detected tracking control signal, eccentricity correction data is generated and stored, and the signal is synchronized with the rotational frequency. And correcting the eccentricity by outputting the stored eccentricity correction data based on the eccentricity correction control method. . 13. A pickup having an objective lens and a tracking actuator for driving the objective lens, for recording information on the disk or reproducing the information recorded on the disk, driving means for rotating the disk, and the disk Frequency generating means for generating a frequency obtained based on the rotation speed of the disk, tracking error signal detecting means for detecting a tracking error signal obtained from the disk via the pickup, and based on the output of the tracking error signal detecting means. hand,
Tracking control signal generating means for generating a tracking control signal for causing a focus of light to follow a track on the optical disk; tracking actuator driving means for driving the tracking actuator; and rotation of the disk obtained via the pickup Rotation phase information detection means for detecting phase information; FG identification means for identifying an output (FG) of the frequency generation means based on the rotation phase information; and eccentricity based on the tracking control signal and the FG. An eccentricity correction signal generating means for generating a correction signal; a memory means for storing the eccentricity correction signal as eccentricity correction data; and a memory control means for controlling output of the eccentricity correction data from the memory means based on the FG. An optical disc device having the same. 14. An optical disk device according to claim 13, wherein said eccentricity correction signal generating means generates an eccentricity correction signal by detecting a rotational frequency component of said disk and a harmonic component thereof of said tracking control signal. An optical disc device characterized by performing: 15. An optical disk device according to claim 13, wherein said rotation phase information is a land / groove signal for identifying whether a track of said optical disk is a land or a groove. apparatus. 16. An optical disk apparatus according to claim 14, wherein said eccentricity correction signal generation means detects a component of said tracking control signal based on a signal for identifying whether the disk is attached or detached. 17. The optical disk device according to claim 13, wherein said memory control means, when starting eccentricity correction, corrects the correction data closest to the average value of all correction data stored in said memory means. An optical disk device for controlling the output of the memory means so as to output the data from the memory device. 18. An optical disk device according to claim 13, wherein said memory control means includes information on a disk radius at a position on the disk followed by said objective lens when detecting a component of said tracking control signal. An optical disk device that generates correction data for each disk radius based on a known frequency characteristic of the tracking actuator and stores the correction data in the memory. 19. A method for controlling a surface shake correction of an optical disk device for recording or reproducing an optical disk while correcting the surface shake of an optical disk, comprising: generating and storing surface shake correction data after the optical disk is mounted. An optical disc apparatus, wherein the stored correction data is used until the optical disc is detached. 20. An eccentricity correction control method for an optical disk apparatus for recording or reproducing an optical disk while correcting the eccentricity of the optical disk, comprising: generating and storing eccentricity correction data after the optical disk is mounted; An eccentricity correction control method, wherein the corrected data is used until the optical disk is detached.