KR19980075513A - Tracking Servo Control of Optical Disc Player - Google Patents

Abstract

The present invention relates to a tracking servo control apparatus for an optical disc player for performing accurate tracking servo by outputting a normalized tracking servo control signal when controlling a tracking servo of an optical disc player.

To this end, the present invention is a tracking servo control apparatus of an optical disc player for controlling a tracking servo by detecting a tracking error based on the amount of light reflected from a disk, wherein the amount of reflected light of the disk is detected and a current value corresponding to the detected amount of light is provided. Light amount detection unit; A current-voltage converter for converting and providing a current value provided by the light quantity detector into a voltage value; A tracking error detector for detecting a tracking error by using a value obtained by adding a voltage value provided by the current-voltage converter and a value obtained by subtracting a voltage value provided by the current-voltage converter; A compensating unit for providing a tracking servo control signal in which the tracking error value is normalized to compensate the tracking error value provided by the tracking error detecting unit; By including a tracking actuator that performs tracking according to the tracking servo control signal provided from the compensation unit, tracking can be performed accurately.

Description

Tracking Servo Control of Optical Disc Player

The present invention relates to a tracking servo control apparatus for an optical disc player for performing accurate tracking servo by outputting a normalized tracking servo control signal when controlling a tracking servo of an optical disc player.

Computer and communication technologies are developing remarkably toward the 21st century information society. As a result, the volume of information such as audio, code information, images, and document information is increasing at a tremendous speed, recording video and audio data on a high-density recording medium that performs high-density recording due to the breakthrough of semi-permanent optical discs, namely, laser technology. And optical disc players have been developed to play them.

Such an optical disc player reproduces an image and / or an audio recorded on an optical disc and outputs it through a screen and / or a speaker, and has a higher signal-to-noise ratio than conventional image and / or audio reproducing apparatus, resulting in better image quality and / or sound quality. It is possible to reproduce signals with no noise, generate no noise due to irregular reproduction and modulation, very little distortion, ghostless, random access, etc. have.

In addition, such an optical disk player includes a compact disk player (CDP), a laser disk player (LDP), a compact disk graphic player (CDGP) and a video compact disk player (VCDP: video). compact disk player) has been developed and widely used, and recently, a digital video disk (DVD) using MPEG-2 moving picture compression technology and a digital video disk player for playing the same have been developed. It is possible to record and play back gigabytes (GB) of data including moving images in an optical disc of 12 cm, and it is also made to be compatible to play current CDs and VCDs.

On the other hand, the optical disc player performs tracking servo to keep the distance between the signal surface of the disc and the objective lens constant. The tracking servo control signal detects a tracking error signal based on the amount of reflected light and compensates for the detected tracking error signal. Tracking servo was performed by providing.

However, when data is recorded and reproduced in such an optical disc player, when a difference occurs between the reflected light of the laser light according to the recording and the reflected light of the laser light according to the reproduction, that is, as shown in FIG. There was a problem in that the track could not be accurately traced due to a difference between A) and the laser light quantity level B during reproduction.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and an object of the present invention is to output a tracking servo control signal that normalizes a tracking error detected from a laser beam reflected light, thereby tracking servo control of an optical disc player for accurately controlling the tracking servo. To provide a device.

A feature of the present invention for achieving the above object is a tracking servo control apparatus of an optical disc player which controls a tracking servo by detecting a tracking error based on the amount of light reflected from a disk, wherein the amount of reflected light of the disk is detected and detected. A light amount detector for providing a current value corresponding to the light amount; A current-voltage converter converting a current value provided by the light quantity detector into a voltage value and providing the converted voltage value; A tracking error detector for detecting a tracking error by using a value obtained by adding a voltage value provided by the current-voltage converter and a value obtained by subtracting a voltage value provided by the current-voltage converter; A compensator for providing a tracking servo control signal normalizing the tracking error value to compensate for the tracking error value provided by the tracking error detector; And a tracking actuator that performs tracking according to a tracking servo control signal provided by the compensation unit.

The above objects and various advantages of the present invention will become more apparent from the preferred embodiments of the invention described below with reference to the accompanying drawings by those skilled in the art.

1 is a diagram showing a tracking servo signal according to recording and reproduction;

2 is a block diagram showing the configuration of a tracking servo control apparatus for an optical disc player according to a preferred embodiment of the present invention;

3 is a detailed block diagram of a tracking servo control device according to the present invention shown in FIG.

<Description of the code | symbol about the principal part of drawing>

10: optical disc 20: tracking actuator

30: light amount detection unit 40: current-voltage conversion unit

50: tracking error detection unit 60: compensation unit

Hereinafter, with reference to the accompanying drawings will be described in detail the operation of the preferred embodiment according to the present invention.

2 is a block diagram showing the configuration of a tracking servo control apparatus for an optical disk player according to the present invention, which detects the optical disk 10 and the amount of light reflected from the optical disk 10 and provides a current value corresponding to the detected amount of light. Calculates the voltage value provided by the current-voltage converter 40 and the current-voltage converter 40, which converts and amplifies the current value provided by the light quantity detector 30, the light quantity detector 30 into a voltage value The tracking error detection unit 50 for detecting a tracking error, the compensation unit 60 for providing a tracking servo control signal normalized and compensated by the tracking error provided from the tracking error detection unit 50, and the compensation unit 60 It consists of the tracking actuator 20 which performs tracking according to a tracking servo control signal.

FIG. 3 is a detailed block diagram of the tracking servo control device shown in FIG. 2, and a detailed operation thereof is as follows.

In the figure, reference numeral 10 denotes an optical disc, and reference numeral 30 is a light quantity detection unit. The light amount detecting unit 30 detects the amount of light reflected from the optical disc 10. The light quantity detecting unit 30 includes a first photodiode 31 and a second photodiode 32, as shown in the drawing, and reflects the optical disc 10. The amount of light received is received and a current value corresponding thereto is provided to the current voltage converter 40.

At this time, the current-voltage converter 40 is composed of a first current-voltage converter 41 and a second current-voltage converter 42, the first current-voltage converter 41 The current value provided from the first photodiode 31 is converted into a voltage value and provided to the tracking error detector 50, and the second current-voltage converter 42 provides a current value provided from the second photodiode 32. Is converted into a voltage value and provided to the tracking error detector 50.

That is, the tracking error detector 50 detects the tracking error by calculating the current values provided from the first current-voltage converter 41 and the second current-voltage converter 42, and thus, the first current-voltage. Provided by the value (E + F) 51 and the first current-voltage converter 41 obtained by adding the voltage value provided by the converter 41 and the current value provided by the second current-voltage converter 42. The tracking error is provided to the compensator 60 by subtracting the voltage value and the voltage value provided by the second current-voltage converter 42.

At this time, the compensator 60 provides the tracking actuator 20 with the tracking servo control signal compensated by normalizing the tracking error provided from the tracking error detector 50. That is, the compensator 60 subtracts the value EF 52 obtained by subtracting the voltage value provided from the first current-voltage converter 41 and the voltage value provided from the second current-voltage converter 42. Tracking normalized by the result of dividing the voltage value provided by the first current-voltage converter 41 and the current value provided by the second current-voltage converter 42 by the value (E + F) 51. The servo control signal is provided to the tracking actuator 20.

Accordingly, the tracking actuator 20 performs accurate tracking according to the tracking servo control signal provided from the compensator 60.

As described above, the tracking servo control apparatus of the optical disc player according to the present invention detects the amount of light reflected from the optical disc, converts a current value corresponding to the detected amount of light into a voltage value, calculates the converted voltage value, and calculates a tracking error. And a tracking servo control signal in which the tracking error is normalized to compensate for the detected tracking error, there is an effect that accurate tracking can be performed.

While the invention has been shown and described with respect to certain preferred embodiments, it will be apparent to those skilled in the art that various modifications, changes and omissions can be made without departing from the spirit and scope of the invention.

Claims (2)

A tracking servo control apparatus for an optical disc player for controlling a tracking servo by detecting a tracking error based on an amount of light reflected from a disk, A light amount detector for detecting a reflected light amount of the disk and providing a current value corresponding to the detected light amount; A current-voltage converter converting a current value provided by the light quantity detector into a voltage value and providing the converted voltage value; A tracking error detector for detecting a tracking error by using a value obtained by adding a voltage value provided by the current-voltage converter and a value obtained by subtracting a voltage value provided by the current-voltage converter; A compensator for providing a tracking servo control signal normalizing the tracking error value to compensate for the tracking error value provided by the tracking error detector; And a tracking actuator configured to perform tracking according to a tracking servo control signal provided by the compensator. The tracking servo control of an optical disc player according to claim 1, wherein the compensator normalizes a value obtained by subtracting a voltage value provided by the current-voltage detector by dividing it by a sum of a voltage value provided by the current-voltage detector. Device.