KR19990012008A - How to adjust the offset of the optical disc player - Google Patents

Abstract

The present invention relates to a method of adjusting an offset level of an optical disc player for measuring and eliminating an offset level that is an error between a tracking error signal detected during playback of an optical disc and a point at which actual tracking matches. A first step of dividing and setting the signal into a plurality of sections, and then detecting a tracking error signal in each set section; A second step of detecting an offset level corresponding to each of the sections by integrating each of the plurality of tracking error signals detected in the first step; A third step of performing tracking servo based on the detected offset level after detecting the offset level corresponding to the current playback position from the offset level measured in response to the respective sections when the optical disc is reproduced; By providing an offset adjustment method of the optical disc player comprising a, it is possible to perform a precise tracking servo has the effect of improving the reliability of the DVDR system.

Description

How to adjust the offset of the optical disc player

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc player, and more particularly, to an offset adjustment method of an optical disc player for measuring and eliminating offset levels present in a tracking error signal.

In general, an optical disc player capable of playing video includes a laser disk player (LDP), a video compact disk player (VCDP), and the like. Compression techniques are used to provide viewers with video and audio by playing back optical discs with video and audio data of several gigabytes (GB).

As described above, the optical disc player has a higher signal-to-noise ratio than conventional video / audio playback devices, so that signals can be reproduced with better image quality / sound quality, no noise due to irregular playback and modulation, and distortion is very low. Not only is there no ghost, but random access is possible, and there are various advantages such as providing various functions such as a music accompaniment function.

On the other hand, in order to accurately read the data recorded on such an optical disc, the optical pickup of the optical disc player must accurately follow the track of the pitch formed on the optical disc.

If the tracking control is not performed smoothly, it is difficult to accurately read the data recorded due to impact or disturbance during reproduction.

Therefore, even if the disk rotates eccentrically, the tracking control is performed so that the laser beam of the optical pickup is accurately followed along the tracks at a predetermined interval. The tracking control device is generally called a tracking servo, and the general operation process thereof is shown in FIG. Referring to the following.

1 is a block diagram illustrating a tracking servo device according to the related art, including a photodetector 10, a current-voltage converter 20, an error detector 30, a difference compensator 40, and a driver 50. )

First, the photo detector 10 is composed of two photo diodes D1 and D2 divided into two, and detects the light reflected from the optical disk through the respective photo diodes D1 and D2, and the detected Generates a current corresponding to light.

The two sets of current-voltage converters 20 are composed of two sets of OP amplifiers. The OP amplifier has a resistor R1 at its inverting input terminal as shown in FIG. 1, and the non-inverting input terminal is grounded. The feedback loop is provided with a loop resistor Rf from the output terminal to the inverting input terminal.

In the pair 21 of the current-voltage converter 20 configured as described above, the current generated by the diode D1 of the photodetector 10 divided into two is converted into a constant voltage, and the converted voltage is converted into an error. It is provided to one input terminal of the detector 30.

In addition, the other pair 22 of the current-voltage converter 20 converts the current generated from one diode D2 of the photodetector 10 divided into a constant voltage, and converts the current into a constant voltage. It is provided to the other input terminal of the error detection unit 30.

At this time, the voltage provided from the current-voltage converter 20 is output as a product of the loop resistance Rf with respect to the current I generated in one diode, and its phase is inverted. That is, the output voltage is output as -I * Rf.

The error detector 30 includes a differential amplifier having two input terminals and one output terminal.

When the voltages provided by the two sets of current-voltage converters 21 and 22 are input to the two input terminals of the error detector 30, respectively, the error detector 30 inputs two inputs input by the current-voltage converters 21 and 22. Amplify the difference voltage between voltages. At this time, the generated voltage is a tracking error signal, which indicates the degree to which the laser beam deviates from the tracks at regular intervals of the optical disk.

The phase compensator 40 compensates for the phase of the focusing error signal generated by the error detector 30, amplifies it, and outputs it as a drive control signal for driving the driver 50.

The driver 50 generates a drive signal for driving the tracking actuator coil by the drive control signal output from the phase compensator 40, and the focusing actuator coil is driven by the drive signal generated by the driver 50.

By driving the actuator coil, the objective lens (not shown) moves left and right, and by the movement of the objective lens, the signal surface of the optical disc is adjusted to be located within a certain depth of focus of the laser beam.

However, even if the tracking error signal is detected as 0 by performing the tracking servo as described above, an offset voltage is generated due to the inclination of the disk, the characteristics of the op amp, the characteristics of the photodiode, and the like. As it is included, each time the optical disc is mounted in the optical disc player, a process of measuring and adjusting the offset voltage is required.

Therefore, in the related art, such offsets are measured and adjusted for a predetermined section at the initial stage of mounting the optical disk.

However, in the related art, since the offset is measured by only one predetermined section and the offset is adjusted, the offset level, which is different depending on the degree of warpage of the optical disc, cannot be sufficiently adjusted.

Accordingly, the present invention has been made in view of the above-described problems, and an object of the present invention is to detect a tracking error signal by sampling a plurality of predetermined sections of all sections of an optical disc, and to calculate an integrated value of the detected tracking error signal. It is to provide an offset adjustment method of an optical disc player that can measure and adjust the offset level.

In order to achieve the above object, the present invention provides an offset level adjustment of an optical disc player for measuring and eliminating an offset level that is an error between a point where a tracking error signal detected during playback of an optical disc becomes zero and an actual tracking match. A method, comprising: a first step of dividing and setting an optical disc into a plurality of sections, and then detecting a tracking error signal in each set section; A second step of detecting an offset level corresponding to each of the sections by integrating each of the plurality of tracking error signals detected in the first step; A third step of performing tracking servo based on the detected offset level after detecting the offset level corresponding to the current playback position from the offset level measured in response to the respective sections when the optical disc is reproduced; It is to provide an offset adjustment method of an optical disc player comprising a.

1 is a block diagram showing a general tracking servo device;

2 is a block diagram of hardware for implementing the offset adjustment method according to the present invention,

3 is a flowchart illustrating an offset adjustment method according to the present invention;

4 is an exemplary diagram showing waveforms of tracking error signals in each section and each section of the optical disc for measuring the offset level according to the present invention;

* Explanation of symbols for main parts of the drawings

10: photodetector 20: current-voltage converter

30: error detection unit 40: phase compensation unit

50: drive unit 100: optical disc player

200: tracking servo device 300: microcomputer

400: storage unit 500: offset adjustment unit

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

2 is a block diagram of hardware for implementing the offset adjustment method according to the present invention, the optical disk player 100, the tracking servo device 200, the microcomputer 300, the storage unit 400, the offset adjustment unit 500 ), An integrator 600.

Hereinafter, the functions of the respective constituent members of the hardware for implementing the offset adjustment method according to the present invention are as follows.

First, the optical disc player 100 performs the original operation of the optical disc such as the reproduction of the optical disc under the control of the microcomputer 200, and the tracking servo device 200 uses the optical disc D mounted in the optical disc player 100. A tracking error signal is detected from the reflected laser beam.

The microcomputer 300 controls the overall operation of the optical disc player 100, and stores position data for a plurality of preset offset measurement sections in an internal memory (not shown), and offsets to adjust the offset level. The adjusting unit 500 is controlled.

The storage unit 400 stores the offset level measured in each preset offset measurement section, and the offset adjusting unit 500 tracks a predetermined offset voltage capable of compensating the offset level under the control of the microcomputer 300. Supply to the servo 200 to adjust the offset.

The integrator 600 integrates a tracking error signal provided from the tracking servo device 200 and provides the integrated value to the microcomputer 300. In this case, the integral value provided by the integrator 600 is an offset level in the offset measurement interval which is preset and stored in the internal memory of the microcomputer 300.

The offset adjustment method of the optical disc player according to the present invention made of the above-described structural members will now be described with reference to FIGS. 3 and 4.

3 is a flowchart illustrating a method for adjusting an offset according to the present invention, and FIG. 4 is a diagram illustrating waveforms of a tracking error signal in each section and each section of the optical disc for measuring the offset level according to the present invention.

First, when the optical disc is loaded into the optical disc player 100 (S 10), the microcomputer 300 tracks for a predetermined time in the first section by referring to the position data of the offset measurement section preset in the storage unit 400. The optical disc player 100 and the tracking servo device 200 are controlled to detect an error.

Under the control of the microcomputer 300, the optical disc player 100 moves the internal optical pickup unit (not shown) to the first offset measurement section, and the tracking servo device 200 detects the tracking error signal in this section. To provide to the integrator 600. (S 20)

The integrator 600 integrates the tracking error signal provided from the tracking servo device 200 and provides the integrated value of the tracking error signal to the microcomputer 300 (S30), wherein the integrated value of the tracking error signal is tracking It will be the offset level of the section where the error signal is detected.

The microcomputer 300 stores the integral value provided by the integrator 600 in the storage unit 400 corresponding to the preset position data of the first section (S 40), and then refers to the internal memory of the microcomputer 300. The next offset measurement section is set (S50).

As a result of the search of step S 50, if there is position data for the next offset measurement section preset in the internal memory of the microcomputer 300, the microcomputer 300 controls the optical disc player 100 and the tracking servo device 200 to perform the next offset. In step S 20, the step S 40 is repeated. (S 60),

On the other hand, if the search result of step S50 does not include the position data for the next offset measurement section preset in the storage unit 400, the microcomputer 300 is assigned to the TOC (Read-in area) of the read-in area of the mounted optical disk Table Of Contents) controls the optical disc player 100 to read the information.

The optical disc player 100 reads TOC information from the lead-in area of the optical disc under the control of the microcomputer 300, and then waits for input of a key signal. (S70)

Subsequently, when a play key signal is generated by a key input unit (not shown) and the generated play key signal is applied to the microcomputer 300 (S80), the microcomputer 300 uses the optical disk mounted in the optical disk player 300. The optical disc player 300 is controlled to play back.

The optical disc player 100 plays back the optical disc mounted therein under the control of the microcomputer 300 (S90), and provides the microcomputer 300 with information on the current playback position, and the microcomputer 300 stores the storage unit. With reference to the position data of the first offset measurement section stored in 400, it is determined whether the current playback position provided by the optical disc player 100 reaches the first offset measurement section.

As a result of the determination of S 100, when the current playback position of the optical disc player 100 reaches the first offset measurement section, the microcomputer 300 withdraws the offset level of the first offset measurement section stored in the storage 400, and withdraws it. The offset adjusting unit 500 may be controlled to adjust the offset level of the tracking servo device in response to one offset level, and the offset adjusting unit 500 may compensate the offset level of the first offset measurement section under the control of the microcomputer 300. The predetermined offset voltage is supplied to the tracking servo 200 to adjust the offset level of the tracking servo device 200.

Thereafter, the microcomputer 300 determines whether the storage unit 400 has the position information for the next offset measurement section, and if there is a next offset section, controls the entire system to repeat the step S120 in step S90 described above. If there is no next offset section, the offset adjustment is stopped.

As described above, according to the present invention, after measuring the offset voltage for each predetermined section for all sections of the optical disk mounted in the optical disk player, and then adjust the offset level for each section according to the measured offset level, optical disk The tracking servo of the player can be performed accurately, thereby improving the reliability of the optical disc player.

Claims (1)

In the offset level adjustment method of an optical disc player for measuring and eliminating an offset level that is an error between a tracking error signal detected during playback of an optical disc and a point where the actual tracking coincides. A first step of dividing and setting the optical disc into a plurality of sections, and detecting a tracking error signal in each set section; A second step of detecting an offset level corresponding to each of the sections by integrating each of the plurality of tracking error signals detected in the first step; In the reproducing of the optical disc, a third step of detecting the offset level corresponding to the current reproduction position from the offset level measured corresponding to each section, and then performing a tracking servo based on the detected offset level is performed. Offset adjustment method of an optical disc player comprising a.