JPH041937A - tracking control device - Google Patents

Abstract

PURPOSE:To surely and automatically detect and correct a tracking position by measuring previously the value of a tracking error signal at the extreme point of the reflected light or at the maximum point of a reproduced signal in plural areas of a disk and storing this measured value in order to use it as the tracking position. CONSTITUTION:A tracking error signal detection means 6 is provided together with an extreme point detection means 15, a tracking position signal generating means 9, a tracking target position storage means 13, and a control means 12. Then the tracking position is measured at plural divided positions on the surface of an optical disk 1 and then stored. A tracking servo operation is carried out at the tracking target position corresponding to the disk position at the signal record/reproduction/erasure states respectively. Thus a sure track following servo operation is automatically attained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a tracking control device for an optical recording and reproducing device used for data file Jv, image files, etc. Conventional techniques Below are examples of conventional tracking control devices. will be explained with reference to the drawings.

FIG. 8 is a block diagram of a conventional tracking control device. In Figure 8, 1 is an optical disk drive 2
3 is an optical beam; 3 is an objective lens; 4 is an optical head; the light beam 2 emitted from the optical head 4 is focused into a minute spot by the objective lens 3, and enters the optical disk 1 to record and reproduce information. A focus servo circuit 5 performs focus servo to focus the light beam 2 on the medium surface of the optical disc 1. 6 is a tracking error signal detection line; 7 is a tracking servo circuit that performs phase complementation (L power amplification, etc.) for the tracking error signal obtained by the tracking error signal detector 6; 8 is a tracking actuator that connects the objective lens 3 to the medium of the optical disk L; Tracking servo is performed to make the light beam 2 follow the information recording track by moving it in a direction substantially perpendicular to the information recording track on the surface. Reference numeral 11 denotes a transporter that moves the optical head 4 and the tracking actuator 8 substantially perpendicular to the information recording track. It moves in the direction.

9 is a tracking position signal generator a; 10 is a subtracter that subtracts the output of the tracking position signal generator 9 from the tracking error signal. The operation of the tracking control device configured as above will be explained below.Conventional tracking control In the device: First, apply the focus servo and after the focus servo starts operating stably, adjust the tracking position so that the average value of the maximum and minimum values of the tracking error signal becomes the tracking position. The output of the signal generator 9 is subtracted to give an offset to the tracking error signal to adjust the position of the tracking servo. However, the problem with conventional tracking control devices is that the value midway between the maximum and minimum values of the main tracking error signal is stored and used as the only tracking position. etc., the optical axis moves and the tracking position changes depending on the position on the disk.

Alternatively, if the light intensity distribution of the reflected light changes in a portion of a read-only (hereinafter abbreviated as ROM) disk where pits exist, the tracking error signal may be offset or regenerated, making it impossible to detect the correct tracking position. The objective is to provide a tracking control device that can reliably and automatically detect and correct the tracking position.

Means to solve the problem To achieve the above purpose! (2) In the tracking control device of the present invention, the tracking error signal detection means, the pole detection means for the reflected light of the light spot from the surface of the optical recording/reproducing medium, and the tracking position signal generation means;
tracking target position storage means; and control means for controlling the tracking position signal generation means and the tracking target position storage means according to the outputs of the pole detection means and the tracking error signal detection means; The tracking error signal obtained when the extreme point of Calculate a tracking position according to the output of the tracking target position storage means corresponding to a plurality of divided areas on the surface of the optical recording and reproducing medium. The apparatus may further include detecting the maximum point of the reproduced signal from the surface of the optical recording/reproducing medium and generating a timing signal. a reproduction signal maximum point detecting means for outputting, in an area where no signal is recorded on the surface of the optical recording/reproducing medium, the control means detects a tracking error when the reflected light extreme point detecting means detects a reflected light extreme point; A signal is stored in the tracking target position storage means, and a maximum point of the reproduction signal is detected by the reproduction signal maximum point detection means by the control means in an area where the signal is previously recorded on the surface of the optical recording/reproduction medium. The tracking error signal obtained when the signal is recorded is stored in the tracking position tracing storage means, and when the signal is recorded/reproduced in an area where no signal is recorded on the surface of the optical recording/reproducing medium, the control means detects the reflected light pole point. Instructing the tracking position signal generating means to output a tracking target value in accordance with the output of the tracking target position storage means corresponding to the tracking error signal when the pole of the reflected light is detected by the means to perform tracking control. ．． %
When a signal is recorded and/or erased in an area on the surface of the optical recording and reproducing medium where a signal is previously recorded, the control means detects a tracking error when the maximum point of the reproduced signal is detected by the maximum point detecting means of the reproduced signal. Even if the apparatus has a structure in which an instruction is given to the tracking position signal generating means in accordance with the output of the tracking target position storage means corresponding to the signal, a tracking target position signal is outputted, and tracking control is performed, the structure operates as described above. In the tracking control device, the value of the tracking error signal at the maximum point of the reflected light or the maximum point of the reproduced signal is measured in advance in multiple areas of the disk, and is stored as tracking position data on the disk surface to determine the tracking position. The inclination of the medium surface changes depending on the position on the disk surface. Even if the tracking position changes due to the presence or absence of pits, the tracking position corresponding to the disk position is read out from the storage means and corrected. There is no offset in the tracking position. It is possible to perform reliable tracking servo without any occurrence. Furthermore, by storing the tracking position by approximating it to a function, the memory capacity can be reduced and the device can be made more compact. Furthermore, in a place where a signal has already been recorded, the tracking position is set to the position where the reproduced signal is maximum, so the tracking position changes between the ROM part and other parts on a ROM disc or a disc with a ROM part and an unrecorded part. A tracking control device according to a first embodiment of the present invention will be described below with reference to the drawings. Block doctor of the tracking control device in the first embodiment FIG. 2 is a flowchart showing the operation of the microprocessor, and FIG. 4 is a disk divided area diagram showing an example of divided areas on the medium surface of an optical disk. In the figure, 1 is an optical disk, 2 is an optical beam, 3
4 is an objective lens, 4 is an optical head, and 5 is a focus servo circuit, which moves the light beam 2 focused into a minute light spot by the objective lens 3 in a direction substantially perpendicular to the medium surface of the optical disk 1. Focus on the top. 6 is a tracking error signal detector which detects the deviation between the light beam 2 reflected from the optical disc 1 and the information recording track on the medium surface of the optical disc 1. 14 is a reflected light amount detector which detects the deviation of the light beam 2 reflected from the optical disc 1.
15 is a pole detector which detects the maximum point or minimum point of the reflected light amount sum output signal of the reflected light amount detector 14 and outputs a timing signal. 9 is a tracking position signal. The generating edge 13 is a tracking target position memory. 12 is a microprocessor which inputs the tracking error signal and the timing signal of the output of the pole detector 15 to control the tracking target position memory 13 and the tracking position signal generator 9.

10 is a subtracter that subtracts the tracking position signal from the tracking error signal. 7 is tracking servo same section
Reference numeral 8 denotes a tracking actuator that controls tracking of the optical spot by moving the objective lens 3 in a direction substantially perpendicular to the information recording track on the medium surface of the optical disk l. A transporter 11 moves the optical head 4 and tracking actuator 8 in a direction substantially perpendicular to the information recording track. Optical disk l, light beam 2, objective lens 3
, optical head 4, focus servo circuit 5, tracking error signal detector 6, tracking servo circuit 7,
Tracking actuator 8, subtractor lO1 transfer device I
I is similar to that of a conventional tracking control device.

The operation of the tracking control device in the first embodiment of the present invention, which is constructed from the above elements, will be explained with reference to FIG. 4 of the second embodiment. FIG. 2 is a flowchart showing the operation of the microprocessor 12 according to the first embodiment of the present invention. FIG.
A2. FIG. 3 is a diagram showing how the disk area is divided into A3 and 4 areas.

With the focus servo being stabilized by the focus servo circuit 5, the microprocessor 12 instructs the transporter 11 to move to the AO area of the disk, and while moving within the area at a substantially constant speed, the pole detector The tracking error signal is read at the timing output of 15 and stored in the address corresponding to the area AO of the tracking target position memory 13.4 Next, the transfer device 11 is instructed to move to the area A1 and move within the area at a substantially constant speed. While moving, a tracking error signal is read from the timing output of the pole detector 15 and is stored in an address corresponding to the AI area of the tracking target position memory 13. Furthermore, the above operation is repeated over the entire area of the disk A2. Repeat in area A3. When recording, reproducing, or erasing a signal, the tracking position signal is read from the address corresponding to the disk area of the tracking target position memory 13 and an instruction is given to the tracking position signal generator 9.
A tracking position signal is output and subtracted from the tracking error signal to perform tracking servo and record, reproduce, and erase the signal.

Note that the accuracy of tracking position detection can be improved by detecting the tracking position a plurality of times within the same area and taking the average; however, the disc may be divided into concentric circles or fan shapes. Fifth
In the figure, the area of the disk is divided into concentric circles and further divided into fan-shaped areas: AO, AI, A2. A3. B.O.

B1. B2. B3. CO, CI, C2
, C3, DO, Di, D2. An example of D3 and 16 divisions is shown.

The present invention is not limited by the shape or number of disk divisions. However, since the disk inclination and tracking position also change depending on the disk installation status, the tracking position detection and storage operation ζ If you do this from time to time, you can detect the tracking position that corresponds to the disc.

Furthermore, if the tracking position is detected and corrected during the seek operation, it is possible to correct changes in the tracking position due to temporal changes in the disk mounting state, etc.Next, tracking control in the second embodiment of the present invention The operation of the device will be explained with reference to Figures 1 and 3. FIG. 3 is a flowchart showing the operation of a microprocessor according to a second embodiment of the present invention.4 The configuration of the second embodiment is the same as that of the first embodiment shown in FIG. The operation of the processor 12 and the signals stored in the tracking target position memory 13 are different from the first embodiment.

With the focus servo stabilized by the focus servo circuit 5, first give an instruction to the transporter 11 to move to the AI area, and while moving within the area at a substantially constant speed, the timing output of the pole detector 15 is output. to read the tracking error signal. Next, the transporter 11 is instructed to move to the area A2, and while moving within the area at a substantially constant speed, the tracking error signal is read from the timing output of the pole detector 15. Furthermore, repeat the above operation over the entire area of the disk.
, A3 and repeat. When the inclination of the disk medium surface changes depending on the disk position, the tracking position changes linearly or curvedly depending on the disk position, so the value of the tracking target position with respect to the disk position can be calculated by linear or quadratic, In order to increase the approximation accuracy, it is possible to approximate with a high-order function, calculate its coefficients, and store them in the tracking target position memory 13. A tracking position signal corresponding to the area is calculated from the stored coefficients and a predetermined function, and an instruction is given to the tracking position signal generator 9 to subtract the tracking position signal from the tracking error signal to perform tracking servo and erase the recording/playback of the readout signal. Since the change in the inclination of the disk medium surface is large in the radial direction of the disk, the approximation function can be approximated by a one-dimensional function in the disk radial direction. This will further improve the accuracy of the approximation.

Note that the present invention is not limited to the approximation method.

Although the accuracy of tracking position detection can be improved by detecting the tracking position multiple times within the same area and taking the average, the disk may be divided into concentric circles or fan shapes. Figure 5 shows the area of the disk. Divide into concentric circles and further fan-shape AO, AI, A2. A3. B.O.

Bl, B2. B3. Co, CI,
C2, C3, DO, Di, D2. An example of D3 and 16 divisions is shown.

The present invention is not limited to the shape or number of disc divisions.The inclination of the disc and the tracking position also change depending on the mounting state of the disc, so the tracking position detection and storage operation is performed when a new disc is mounted. By doing so, the tracking position corresponding to the disc can be detected.

Furthermore, by detecting and correcting the tracking position during the seek operation, it is possible to correct changes in the tracking position due to temporal changes in the disk mounting state, etc. FIG. 6 shows the third embodiment of the present invention using a microprocessor. Block of tracking control device in embodiment @ 7th
The figure is a flowchart showing the operation of the microprocessor.

In Figure 6, 3 is the objective lens, 4 is the optical spatula K
Reference numeral 5 denotes a focus servo circuit that moves the light beam 2 narrowed into a minute spot by the objective lens 3 in a direction substantially perpendicular to the medium surface of the optical disk I and focuses it on the medium surface of the optical disk I. 6 is a tracking error signal detector that detects the deviation between the light beam 2 reflected from the optical disk 1 and the information recording track on the medium surface of the optical disk 1. 14 is a reflected light amount detector that detects the amount of light beam 2 reflected from the optical disk 1. 15 is a pole detector which detects the maximum point or minimum point of the reflected light quantity sum output signal of the reflected light quantity detector 14 and outputs a timing signal. 16 is a reproduction signal detector which detects the reproduction from the optical disc l. Find the signal level. 17 is a maximum point detector which detects the maximum point of the output signal of the reproduced signal detector 16 and outputs a timing signal. 9 is a tracking position signal generator fL13 is a tracking target position memory. 12 is a microprocessor which inputs the tracking error signal, the timing signal of the output of the extreme point detector 15, and the output of the local maximum point detector 17, and controls the tracking target position memory 13 and the tracking position signal generator 9.

IO is a subtracter that subtracts the tracking position signal from the tracking error signal, and 7 is the same section as the tracking servo. 8
A tracking actuator moves the objective lens 3 in a direction substantially perpendicular to the information recording track on the medium surface of the optical disk 1, thereby performing tracking servo of the optical spot. Reference numeral 11 denotes a transporter that moves the optical head 4 and tracking actuator 8 in a direction substantially perpendicular to the information recording track.
, the focus servo circuit 5, the tracking error signal detector 6, the tracking servo circuit 7, the tracking actuator 8, the subtracter 10, and the transfer device 11 are similar to those of the conventional tracking control device, and are composed of the above elements. The operation of the tracking control device according to the third embodiment of the present invention will be explained with reference to FIG. 7. FIG. 7 is a flowchart showing the operation of the microprocessor according to the third embodiment of the present invention. With the focus servo stabilized by the focus servo circuit 5, first give an instruction to the transfer device 11 to move to a first predetermined area where a predetermined signal is not recorded. While moving within the area at a substantially constant speed, a tracking error signal is read from the timing output of the pole detector 15 and is stored in an address corresponding to the first area of the tracking target position memory 13. Next, an instruction is given to the transporter 11 to move to a second predetermined area in which a predetermined signal is recorded in advance, and while moving within the second area at a substantially constant speed, the maximum point detector 17 is moved. The tracking error signal is read by the timing output of the tracking target position memory 1.
The data is stored at an address corresponding to the second area of No.3.

Further, the above operation is repeated until the entire area of the disk is stored in the tracking target position memory 13. When recording, reproducing, and erasing signals, the tracking target position signal is read from the address corresponding to the disk area of the tracking target position memory 13, and recording, reproducing, and erasing of the signal is performed.

Note that the effect of correcting the tracking position can be improved by further dividing the area on the disk in which signals are prerecorded and the area in which no signal is recorded into a plurality of areas and storing the tracking position directly or by approximating it as a function.

Note that the disk tilt and tracking position change depending on the disk installation status, so it is best to perform the tracking position detection and storage operation when a new disk is installed.Furthermore, the tracking position can be detected and stored during the seek operation. This correction allows you to correct changes in the tracking position due to temporal changes in the disk installation status, etc.Furthermore, detecting the tracking position during a seek operation and correcting it allows you to correct changes in the tracking position due to temporal changes in the disk installation status, etc. Effects of the invention that can correct changes As explained above, the present invention measures the tracking position at a plurality of divided positions on the surface of the disk medium.Memorizes and performs tracking corresponding to the disk position when recording, reproducing, and erasing signals. Since tracking servo is performed at the target position, reliable track following servo can be performed. Further, by approximating the tracking position at a plurality of divided positions on the disk medium surface to a function and storing the coefficients, the memory capacity can be reduced. Further, in a place where a signal has been recorded in advance, tracking servo is performed at a position where the level of the reproduced signal is maximized, thereby making it possible to achieve reliable track following servo even with a ROM disk missing or a partial ROM disk.

[Brief explanation of the drawing]

FIG. 1 shows the blocks of the tracking control device in the first embodiment of the present invention using a microprocessor.
The figure is a flowchart showing the operation of the first embodiment of the present invention using a microprocessor, FIG. 3 is a flowchart showing the operation of the second embodiment of the invention using a microprocessor, and FIG. Fig. 5 shows the partitioning of the disk area in the second embodiment of the invention & Fig. 6 shows the third embodiment of the invention using a microprocessor. FIG. 7 is a flowchart showing the operation of the third embodiment of the present invention using a microprocessor, and FIG. 8 is a block diagram of a tracking control device in a conventional example. be. 1... Optical disk closed 2... Light beam entered 3... Objective lens x 4... Optical head 5... Focus servo same section 6... Tracking error detection same section 7... Tracking servo Same area 8. Tracking actuator 9... Tracking position signal generation image 10.
Subtraction a11・・Transfer line 12・・Microprocessor 13・・Tracking target position memory device 14・
・Reflected light amount detector 15... Name of pole detector agent Patent attorney Shigetaka Awano and one other person

Claims (11)

[Claims] (1) Tracking error signal detection means for detecting a deviation between a light spot focused on the surface of an optical recording/reproducing medium and a signal recording/reproducing track and outputting a tracking error signal indicating the deviation; means for moving the signal in a direction substantially perpendicular to the signal recording/reproducing track; pole detecting means for detecting the pole of the reflected light of the optical spot from the surface of the optical recording/reproducing medium and outputting a timing signal; and a target position of the tracking servo. a tracking position signal generating means for outputting a signal; a tracking target position storing means for storing a target position of the tracking servo; and a tracking position signal generating means according to the outputs of the pole detecting means and the tracking error signal detecting means. control means for controlling the tracking target position storage means, while the moving means moves the light spot at a substantially constant speed in a direction substantially perpendicular to the signal recording/reproducing track; The tracking error signal when the pole point is detected is stored in the tracking target position storage means in a plurality of divided areas on the surface of the optical recording and reproducing medium, and the signal is recorded and reproduced on the signal recording and reproducing track. Sometimes, an instruction is given to the tracking position signal generating means according to the output of the tracking target position storage means corresponding to a plurality of divided areas on the surface of the optical recording/reproducing medium, and the tracking position signal is outputted. A tracking control device characterized by performing control. (2) The tracking control device according to claim 1, wherein the tracking position is detected when the optical information recording/reproducing disk is mounted and is stored in the tracking target position storage means. (3) The tracking control device according to claim 1, wherein a tracking position is detected during a seek operation and the tracking target position stored in the tracking target position storage means is corrected. (4) Tracking error signal detection means for detecting a deviation between a light spot focused on the surface of an optical recording/reproducing medium and a signal recording/reproducing track, and outputting a tracking error signal indicating the deviation; a means for moving the signal in a direction substantially perpendicular to the signal recording/reproducing track; a pole detecting means for detecting a pole of the reflected light of the optical spot from the surface of the optical recording/reproducing medium and outputting a timing signal; A tracking position generating means outputs a target position signal, a tracking target position storing means stores the target position of the tracking servo, and the tracking position signal is calculated based on the outputs of the pole detecting means and the tracking error signal detecting means. comprising arithmetic control means for controlling the generating means and the tracking target position storage means, while the moving means moves the light spot at a substantially constant speed in a direction substantially perpendicular to the signal recording/reproducing track;
The arithmetic control means detects the tracking error signal when the pole point of the reflected light is detected by the pole detection means in a plurality of divided regions on the surface of the optical recording/reproducing medium and approximates it to a predetermined function. The coefficients of the functions are stored in the tracking target position storage means, and when recording/reproducing signals on the signal recording/reproducing track, the coefficients of the functions stored in the tracking target position storage means are used to store the coefficients on the surface of the optical recording/reproducing medium. A tracking control device, characterized in that the tracking control device calculates a tracking position corresponding to an area, gives an instruction to the tracking position signal value generating means, outputs a tracking target position signal, and performs tracking control. (5) The tracking control device according to claim 4, wherein the tracking target value is detected when the optical information recording/reproducing disk is mounted and is stored in the tracking target position storage means. (6) Detect the tracking target position during the seek operation,
5. The tracking control device according to claim 4, wherein the tracking target position stored in the tracking target position storage means is corrected. (7) Tracking error signal detection means for detecting a deviation between a light spot focused on the surface of an optical recording/reproducing medium and a signal recording/reproducing track, and outputting a tracking error signal indicating the deviation; means for moving the signal in a direction substantially perpendicular to the signal recording/reproducing track; a pole detecting means for detecting a polar point of the reflected light of the optical spot from the surface of the optical recording/reproducing medium and outputting a timing signal; and the optical recording/reproducing medium. reproduction signal maximum point detection means for detecting a maximum point of a reproduction signal from a medium and outputting a timing signal; tracking position signal generation means for outputting a tracking servo target position signal; and tracking for storing the target position of the tracking servo. Control for controlling the tracking position signal generating means and the tracking target position storing means in accordance with the outputs of the target position storing means, the reflected light pole point detecting means or the reproduced signal maximum point detecting means and the tracking error signal detecting means. A tracking control device comprising means. (8) While the moving means moves the optical spot at a substantially constant speed in a direction substantially perpendicular to the signal recording/reproducing track, the control means detects the pole of reflected light in an area where no signal is recorded on the surface of the optical recording/reproducing medium. A tracking error signal when a polar point of reflected light is detected is stored in the tracking target position storage means, and the control means controls the reproduction signal to reach a maximum in an area on the surface of the optical recording/reproducing medium where a signal is recorded in advance. A tracking error signal when the polar point of the reflected light is detected by the point detection means is stored in the tracking target position storage means, and when the signal is recorded on the signal recording and reproducing track and being erased, the signal is recorded on the surface of the optical recording and reproducing medium. In the area where no signal is recorded, the control means controls the tracking position signal generating means in accordance with the output of the tracking target position storage means corresponding to the tracking error signal when the pole of the reflected light is detected by the pole detection means. The control means outputs a tracking position signal to perform tracking control, and in the area where a signal is recorded in advance on the surface of the optical recording/reproducing medium, the control means detects the maximum of the reproduction signal using the reproduction signal maximum point detection means. A claim characterized in that tracking control is performed by instructing the tracking position signal generating means to output a tracking position signal in accordance with an output of the tracking target position storage means corresponding to a tracking error signal when a point is detected. Item 7. Tracking control device according to item 7. (9) The control means detects the tracking error signal in a plurality of areas on the surface of the optical recording/reproducing medium when the pole point of the reflected light is detected by the pole detection means, approximates it to a function, and calculates the coefficient to the tracking target position. When the signal is stored in the storage means and recorded on the signal recording/reproducing track, and then recorded/reproduced, the tracking position is calculated by calculating the value of the function of the output of the tracking target position storage means corresponding to the area on the surface of the optical recording/reproducing medium. 9. The tracking control device according to claim 8, wherein the tracking control device performs tracking control by giving an instruction to the signal generating means and outputting a tracking target value. (10) The tracking control device according to claim 8, wherein the tracking target value is detected and stored in the position storage means when the optical information recording/reproducing disk is mounted. (11) The tracking control device according to claim 10, wherein a tracking position is detected during a seek operation and the tracking target position stored in the position storage means is corrected.