KR20020010387A - Method for playing of an optical disk - Google Patents

Abstract

PURPOSE: An optical disk playing method is provided to detect focusing and tracking offset values with which optimum amount of jitter is detected from an optical disk, thereby performing optimized playing of the optical disk. CONSTITUTION: While an objective lens of an optical pick-up is moved from the center of an optical axis by tracks, an optimal tracking offset value is determined from characteristic of a signal reproduced from a moved position. On the basis of the determined tracking offset value, optical disk is played while tracking operation is performed. The optimal tracking offset value is determined in a manner that the amount of jitter is detected from the reproduced signal and an offset value with respect to the minimum amount of jitter is determined as the optimal offset value.

Description

Optimal playback method for optical disks {Method for playing of an optical disk}

The present invention relates to a method of detecting an offset value of the minimum amount of jitter of an optical disc and adjusting the value so that the value is maintained, so that the optimal reproduction of the optical disc is achieved.

Characteristic error of each optical part such as astigmatism, coma, spherical aberration, etc., optical noise caused by assembly error due to mismatch of optical axis generated during assembly, electrical noise caused by each circuit part, power supply, etc., rotation of spindle motor Jitter occurs when the optical disc is played back due to factors such as speed change and deformation of the optical disc itself.

Fig. 1 shows a configuration of a general optical disc drive device for reproducing an optical disc while minimizing the jitter amount of such an optical disc, and includes: an optical pickup 20 for reading recorded data on the optical disc 10; An R / F unit 30 for filtering the signal detected by the optical pickup 20 and outputting it as a binary signal; A digital signal processor (40) for restoring the binary signal to original data with its clock synchronized with the binary signal; A focusing servo unit 51 for performing a focusing correction operation of the optical pickup 20; A tracking servo unit 52 for performing a tracking correction operation of the optical pickup 20; A servo control unit 50 controlling the focusing servo unit 51 and the tracking servo unit 52 based on a focusing error (FE) signal and a tracking error (TE) signal generated and output from the optical pickup 20; A sled servo unit 53 for horizontally moving the optical pickup 20 through a sled motor 21; A spindle servo unit 54 for rotating the optical disc through the spindle motor 11; An A / D converter 60 for converting and outputting the signal detected by the optical pickup 20 into digital data; And controlling the reproduction process of the optical disc 10 and the signal flow between the respective components, detecting the jitter amount of the reproduction data from the converted digital data, and setting the focusing offset of the servo controller 50 based on this. The microcomputer 70 is configured to be included.

Conventionally, when the optical disk is inserted and seated in the optical disk driving apparatus as shown in FIG. 2 (S1), the servo controller 50 applies control signals to the focusing servo unit 51 and the tracking servo unit 52, respectively. A focusing servo operation and a tracking servo operation for variably controlling the position of an objective lens provided in an actuator of the optical pickup 20 are performed. The focusing servo unit 51 is controlled to detect a focusing error signal from the light reflected from the optical disc 10, and focusing is adjusted to accurately form an optical focus on the signal surface of the optical disc 10 (S2), From now on, the focusing state is maintained (S3). Next, the servo control unit 50 controls the tracking servo unit 52 so that the optical focus of the optical pickup 20 at an arbitrary position (for example, the center of the optical disc 10) is focused on the optical disc 10. Tracking is adjusted to be accurately positioned on the track (Tracking Balance Adjustment), and then keeps tracking on (S4).

In this operation state, the A / D converter 60 samples the signal output from the optical pickup 20 and outputs a digital value to the microcomputer 70, and the microcomputer 70 outputs the A / D. The amount of jitter is detected based on the digital conversion value input from the D converter 60, and the focusing offset value at which the jitter is minimized is detected based on this (Focus Bias Adjustment) (S5). The microcomputer 70 applies the focusing offset value thus detected to the servo controller 50 to maintain the offset value until the optical disc 10 is ejected. 20 and the reproducing operation of the optical disc 10 are performed (S6).

However, in the conventional optical disc reproducing method as described above, there are tens of thousands of tracks on the optical disc, and the tracking offset value that minimizes the jitter amount in the inner and outer circumferences of the optical disc does not coincide with the vibration, deformation, and the like of the optical disc. Although the tracking is adjusted only on a single track, the amount of jitter detected at the inner and outer circumferences of the optical disc may not always be the minimum value but may exceed the allowable range. In this case, the optical disc may not be played normally. There was a problem of not being.

Accordingly, the present invention has been made to solve the above problems, and the optimum reproduction of the optical disc is performed by detecting the focusing and tracking offset values at which the optimum amount of jitter is detected for the optical disc, thereby enabling the optimal reproduction of the optical disc. The purpose is to provide a method.

1 shows a configuration of a general optical disc drive device,

FIG. 2 shows the flow of a conventional optical disc reproducing method made from the structure of FIG.

FIG. 3 shows the configuration of a preferred embodiment of the optimal reproducing method of the optical disc according to the present invention made up from the configuration of FIG.

4 shows, for example, the amount of jitter detected from the track position on the optical disc.

※ Explanation of code for main part of drawing

10: optical disc 11: spindle motor

20: optical pickup 21: sled motor

30: R / F part 40: digital signal processing part

50: servo control unit 51: focusing servo unit

52: tracking servo unit 53: sled servo unit

54: spindle servo part 60: A / D converter

70: micom

In order to achieve the above object, an optimal method for reproducing an optical disc according to the present invention is to move an objective lens of an optical pickup on an arbitrary track by an arbitrary track from the center of the optical axis to an inner circumferential / outer circumferential direction. A first step of determining an optimal tracking offset value from a characteristic of a signal to be reproduced and outputted from; And a second step of performing a reproducing operation while performing a tracking operation on the basis of the determined offset value.

Hereinafter, a preferred embodiment of an optical disc optimal playback method according to the present invention will be described with reference to the accompanying drawings.

FIG. 3 shows the flow of a preferred embodiment of the optimal reproducing method of the optical disc according to the present invention. Hereinafter, the reproducing method of FIG. 3 according to the present invention will be described in detail with reference to FIG.

First, as described above, after the optical disk 10 is inserted and mounted, the process of detecting the focusing offset value in the focusing and tracking servo operation ON state (Focus Bias Adjustment) is performed in the same manner as described above (S11 to S15). The microcomputer 70 detects the tracking offset value while performing the tracking shift operation in the state where the focusing offset value is detected as described above. This process is as follows.

First, the servo controller 50 controls the optical pickup at an arbitrary position (for example, the center of the optical disc 10) through the sled servo unit 53 under the control of the microcomputer 70. 20) the objective lens is shifted, and the objective lens is moved by a predetermined track (for example, one track) predetermined from the current position in the inner circumferential direction, and the A / D converter 60 is moved by the objective lens. Sampling the signal detected from the position to output a digital value to the microcomputer 70, the microcomputer 70 detects the jitter amount based on the digital conversion value input from the A / D converter 60 You will remember this.

While the above operation is continuously performed for a predetermined time and the microcomputer 70 detects the jitter amount at various positions in the inner circumferential direction, the servo controller 50 controls the control of the microcomputer 70. Accordingly, the objective lens of the optical pickup 20 is moved back to its original position before the movement, and the objective lens of the optical pickup 20 is previously designated in the circumferential direction again from the moved current position (center of the optical disc 10). The predetermined track (for example, 1 track) is moved. In addition, the A / D converter 60 samples a signal detected from the moved position of the objective lens and outputs a digital value to the microcomputer 70, and the microcomputer 70 outputs the A / D converter 60. The amount of jitter is detected and stored based on the digital conversion value inputted from (S16).

The above operation is continuously performed for a predetermined time so that the microcomputer 70 detects the jitter amount at various positions in the inner circumferential direction and the outer circumferential direction, and the microcomputer 70 stores the stored jitter amount value. Compared with each other, as shown in Fig. 4, the track position on the optical disc 10 is checked for the detected jitter amount as the minimum value, and the tracking offset value corresponding to the checked track position is detected (S17).

When the tracking offset value is detected as described above, the microcomputer 70 performs the tracking operation based on the detected tracking offset value until the optical disc 10 is ejected, that is, the detected tracking offset value. The objective lens of the optical pickup 20 is shifted by a predetermined angle from the center of the optical axis so that the optical pickup 20 is maintained, and the reproducing operation is performed while the deviation amount of the objective lens is continuously maintained (S18).

In the above embodiment, the micom 70 moves the objective lens of the optical pickup 20 in the inner and outer circumferential directions as described above, and then tracks the offset value based on the jitter amount detected at the moved position. Although it may be detected, the jitter amount detected in each of the moving positions of the objective lens of any one direction, that is, the optical pickup 20 by only a predetermined track, is not performed in both the inner and outer circumferential directions. The tracking offset value may be detected based on, and the tracking offset value may be detected based on the amount of jitter respectively detected at the moved position by moving the objective lens of the optical pickup 20 by only a predetermined track in the circumferential direction. have.

In addition, in the above embodiment, the tracking offset value may be detected by detecting the jitter amount of one or more times in the moved track while moving the objective lens of the optical pickup 20 by any track in the circumferential / outer circumferential direction.

Also, as in the above embodiment, the focusing and tracking offset values may be detected from the jitter amount of the reproduction signal, but the focusing and tracking offset values are detected using the signal level of the high frequency reproduction signal (RF signal) instead of the jitter amount. Can be implemented.

The optimal reproducing method of the optical disc according to the present invention, as described above, detects the amount of jitter at various positions in the inner / outer circumferential direction of the optical disc as well as the tracking offset value at the time of reproducing the optical disc, and the tracking offset value at which the jitter is minimized By doing so, it is a useful invention that the optimal reproducing operation is achieved while the detected focusing and tracking offset values are maintained until the optical disc is ejected.

Claims (4)

In the optical disc playback method, A first tracking value for determining an optimal tracking offset value from a characteristic of a signal reproduced and output from a moving position while moving an objective lens of an optical pickup on an arbitrary track by an arbitrary track from the center of the optical axis to the inner / outer circumferential direction step; And And a second step of performing a reproducing operation while performing a tracking operation on the basis of the determined offset value. The method of claim 1, In the first step, the jitter amount is detected from the reproduced signal, and the optical recording according to the detected jitter amount determines an offset value for the jitter amount whose value is the minimum value as an optimum offset value. Optimal recording method of media. The method of claim 2, Wherein the first step detects the amount of jitter while moving the objective lens of the optical pickup on an arbitrary track by one or more tracks from the center of the optical axis in the inner / outer circumferential direction. The method of claim 2, The first step is the optimum recording method of the optical recording medium, characterized in that for measuring the jitter amount at least once in the moved track.