KR100188535B1 - Tracking control system of optical disc drive - Google Patents

Abstract

The present invention enables accurate reproduction of a predetermined signal while optical tracking in accordance with a track of a signal recorded on an optical disc.

According to the present invention, four light-receiving elements (11) are provided in which the optical disk is accurately tracked to reproduce the recorded data cleanly regardless of the pitch of the data recorded on the optical disk. A plurality of auxiliary light receiving elements 15, 15A (16, 16A) ... are arranged in a row on both sides of the left and right sides of ... 14), and these auxiliary light receiving elements 15, 15A (16, 16A) ... The optical disc is detected by the detection signals of the auxiliary light receiving elements 15, 15A or (16, 16A) ... which determine the pitch of the recording data of the optical disc reproduced by the detection signal and detect the light at the same pitch as the pitch of the recording data. Control tracking of

Description

Tracking Control System of Optical Disc Driver

1 is a view showing an arrangement of light receiving elements by a conventional control system.

(A) and (b) of FIG. 2 are diagrams for explaining the generation of a pitch and a tracking error of a signal recorded on an optical disc.

3 is a view showing an arrangement state of the extinction water by the control system of the present invention.

Fig. 4 (a) and (b) are diagrams for explaining a tracking operation according to the pitch of a signal recorded on an optical disc.

5 is a signal flow diagram showing the operation of the control system of the present invention.

* Explanation of symbols for main parts of the drawings

11 to 14: light receiving element 15, 15A, 16, 16A: auxiliary light receiving element

17: pitch

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracking control system of an optical disc driver that enables accurate reproduction of a predetermined signal while optical tracking in accordance with a track of a signal recorded on an optical disc such as a compact disc and a video disc.

In general, an optical disk converts and records various data including a video and audio signal into a digital signal, and reproduces the data using a light such as a laser. The optical disk can record and reproduce a large amount of data in a limited size. It is expanding.

When predetermined data is recorded on an optical disk, data is stored at a constant pitch while drawing a constant track.

Therefore, when the stored data is played back, the tracks must be played back in the same manner as when the data is recorded so that the data can be played back correctly without any error.

In the same manner as when recording data on the optical disk, light is emitted to the optical disk to reproduce the data while drawing a track, and the light receiving element detects that the emitted light is reflected from the optical disk.

Conventional tracking error detection methods include three-beam method and one-beam method. Among them, the three-beam method is the most frequently used method, and the structure is complicated and difficult to adjust. The one-beam method includes disk tilt and disk. This method is used when detecting a defect, a false signal, or an offset.

1 is a view showing an arrangement of a conventional light receiving element.

Here, reference numerals 1 to 4 denote light receiving elements for reproducing data recorded on the optical disc, and the light receiving elements 1 to 4 are connected to each other while forming a square, and the light receiving elements 1 to 4 are outside of the optical discs. Auxiliary light receiving elements 5 and 5A for tracking are provided so as to control tracking of the optical disc with detection signals of these auxiliary light receiving elements 5 and 5A.

This conventional technique is based on the light (6) (6A) 6B which the light receiving elements 1-4 and the light receiving element 5 (5A) respectively detect as shown in FIG. If the pitch 7) and the position of the pitch 7 where data is recorded on the optical disc are the same, the tracking of the optical disc is precisely controlled by the signals of the auxiliary light receiving elements 5 and 5A, that is, the auxiliary light receiving element 5 ( The tracking error can be detected by the difference between the detection signals respectively detected by 5A), and the tracking can be controlled by the detected error to accurately track the optical disc.

However, as shown in (b) of FIG. 2, if the position of the pitch 7 of the optical disc is changed, the track of the optical disc cannot be accurately detected from the signal of the auxiliary light receiving elements 5 and 5A, thereby tracking There was a problem in that an error occurred and the recorded signal could not be reproduced cleanly, and the recorded signal could not be reproduced in case of a serious tracking error.

It is therefore an object of the present invention to provide a tracking control system of an optical disc driver that accurately tracks an optical disc and reproduces the recorded data cleanly even when the position of the pitch on which the data is recorded changes.

In order to achieve the above object, the present invention provides a three-beam (optical) method for detecting a tracking error signal. A light receiving element is provided so as to control the tracking of the optical disk by selecting a particular auxiliary light receiving element which detects light reflected at the pitch at which the data of the optical disk is recorded during reproduction of the optical disk.

Hereinafter, a tracking control system of an optical disk driver of the present invention will be described in detail with reference to the accompanying drawings of FIGS. 3 to 5.

3 is a view showing the arrangement of the light receiving element by the tracking control system of the present invention. As shown therein, the present invention is provided with auxiliary light receiving elements 15 and 15A for tracking the optical disks on the left and right sides of the four light receiving elements 11 to 14 coupled to each other in a square to reproduce data recorded on the optical disk. 16 and 16A are provided to control the tracking of the optical disc with the detection signals of these light receiving elements 15 and 15A and 16 and 16A.

The present invention in which the light receiving elements 11 to 14 and the auxiliary light receiving elements 15 and 15A and 16 and 16A are arranged as described above is used to convert an optical output element (not shown) into an optical disc when the optical disc is reproduced. When light (three beams) is emitted, light is reflected from the pitch 17 of the disk and is incident on the light receiving elements 11 to 14 and the light receiving elements 15 and 15A (16 and 16A).

At this time, when the optical disk on which data is recorded is reproduced as shown in FIG. 4A, the light receiving elements 11 to 14 and the auxiliary light receiving elements 15 and 15A are reflected back from the pitch 17 and returned. The light 18, 19, 19A is received, but the auxiliary light receiving elements 16, 16A receive light 20, 20A, which is reflected back from a portion slightly deviated from the pitch 17.

Therefore, in this case, the tracking is controlled by the signals of the light 19 (19A) detected by the auxiliary light receiving elements 15 and 15A, respectively, to calculate the difference between the signals detected by the auxiliary light receiving elements 15 and 15A, respectively. The calculated difference value drives the actuator of the pickup unit (not shown in the drawing) for precise tracking control.

On the other hand, when the optical disk on which data is recorded is reproduced in the state where the pit is changed as shown in Fig. 4B, the light receiving elements 11 to 14 and the auxiliary light receiving elements 16 and 16A are separated from the pitch 17. The reflected light 18, 19, 19A is received, but the auxiliary light receiving elements 15, 15A receive the light 19, 19A, which is reflected back from the pitch 17. do.

Therefore, in this case, the tracking is controlled by the signals of the light 20 (20A) detected by the auxiliary light receiving elements 16, 16A, respectively, and the difference between the signals detected by the auxiliary light receiving elements 16, 16A, respectively, is calculated. Drive the actuator of the pickup part with the calculated difference value to control accurately tracking.

5 is a signal flowchart showing a tracking control system of the optical disk driver of the present invention. As shown in the drawing, when the optical disk is reproduced, light is emitted to the optical disk by the optical output element of the pickup unit, and the reflected light 18, 19, 19A, 20, 20A is received by the light receiving elements 11-14 and The auxiliary light receiving elements 15 and 15A and 16 and 16A are respectively detected.

When the reflected light 18 (19, 19A) 20, 20A is detected, the level of the optical signal is compared by comparing the levels of the optical signals detected by the respective auxiliary light receiving elements 15, 15A (16, 16A). The largest auxiliary light receiving element 15, 15A or the auxiliary light receiving element 16, 16A is selected, the level difference between the selected auxiliary light receiving element 15, 15A or the auxiliary light receiving element 16, 16A is calculated, and the calculated By level difference, the pickup drives the actuator to adjust tracking.

In the above description, the tracking is controlled by installing the auxiliary light receiving elements 15, 15A, 16 and 16A on the outside of the light receiving elements 11 to 14, but the light receiving elements 11 to 14 are implemented in the present invention. A plurality of auxiliary light receiving elements are provided outside of 14), and the auxiliary light receiving element which detects light having the same pitch as the pitch on which the data is recorded by judging the pitch at which data is recorded on the optical disk by the detection signals of these light receiving elements is selected. And tracking.

As described above, the present invention provides a plurality of auxiliary light-receiving elements on the outside of the light-receiving element, and selects an auxiliary light-receiving element that detects light having a pitch equal to that of data recorded on an optical disk to be reproduced among these auxiliary light-receiving elements. By adjusting the tracking, data can be reproduced while accurately tracking all kinds of optical discs having different recording pitches of data.

Claims (2)

When the optical disc is reproduced by installing a plurality of auxiliary light receiving elements (15, 15A) (16, 16A) on both left and right sides of the light receiving elements (11 to 14) that are coupled to each other in a square and receive data recorded on the optical disc. A tracking control system for an optical disc driver, characterized in that the tracking of the optical disc is controlled by selecting an auxiliary light receiving element that receives light reflected at a pitch (17) at which data of the optical disc is recorded. The tracking control system according to claim 1, wherein the auxiliary light receiving elements (15, 15A) (16, 16A) select the one with the highest level of the light detection signal.