KR19990069672A - How to adjust servo device of optical disc player - Google Patents

Abstract

The servo device adjustment method of the disclosed optical disc reproducing apparatus relates to the servo device adjustment method of the optical disc reproducing apparatus which repeatedly adjusts the tracking balance and the focus balance adjustment.

The present invention provides a first step of adjusting an offset of a focus and tracking error signal, a second step of adjusting a DC balance of a tracking error signal with an offset adjusted therein, and adjusting a tracking balance to within an error range, and the first step. Adding a DC bias signal to the focus error signal whose offset is adjusted in step 3 to adjust the focus balance to within the error range so that the amplitude of the RF signal is maximum, and repeating the tracking balance of the second step A fourth step of adjusting, a fifth step of repeatedly adjusting the focus balance of the third step, and detecting a phase difference between the closed loop output signal and the pure disturbance signal by the second adjustment of the tracking balance, A sixth step of adjusting the tracking gain to enter, and a closed loop by adjusting the focus balance secondary of the fifth step And a seventh step of adjusting a focus gain to detect a phase difference between the output signal and the pure disturbance signal and falling within a predetermined range, and an eighth step of adjusting an RF AGC for correcting changes over time of the RF signal. do.

Therefore, by repeatedly adjusting the balance adjustment performed only once, the accuracy and the accuracy of the adjustment state are increased, thereby improving the accuracy of the servo operation state.

Description

How to adjust servo device of optical disc player

The present invention relates to a servo device adjustment method of an optical disc player.

More specifically, the present invention relates to a servo device adjustment method of an optical disc reproducing apparatus, in which the accuracy of the servo disc of the optical disc reproducing apparatus is improved by repeating and automatically adjusting the automatic adjustment performed only once.

In general, optical discs such as compact discs (CDs), laser discs (LDs), and video compact discs (VCDs), etc., are robust as a storage medium that is designed to allow data such as audio and video to be recorded in a defined effective area and to be reproduced therefrom. In addition, since the recorded data is not easily damaged and has the advantage of being reproduced cleanly without noise using a light beam, its use is gradually increasing.

The optical disc reproducing apparatus is a device for reproducing predetermined data recorded on such various optical discs, and in order to faithfully reproduce predetermined data desired by the user, an optical output servo mechanism, a tracking servo mechanism, a focus servo mechanism, a fixed speed servo mechanism, etc. Various servo mechanisms of the optical disc reproducing apparatus must be operated correctly.

That is, an optical disk made of a substrate made of a plastic material causes the disk to curl and undulate due to thermal distortion during molding, resulting in up and down shaking on the surface of the disk and damage to the roundness of the track.

Further, when the disc is mounted on the turntable of the optical disc drive, warping occurs due to the weight of the disc itself. As described above, the disk vibration and the track shaking are fixed, and the drive also has the track shaking due to the surface vibration caused by the inclination and reciprocation of the turntable.

In order to be able to record and reproduce information accurately without being affected by the surface vibration or track shaking, the FOCUS and TRACKING error signals are detected, and the precise balance adjustment or gain of the servo system is performed. Coordination is an important technique.

The focus error detection moves the objective lens of the optical pickup up and down to collect the distance between the lens and the optical disk within the depth of focus of the lens, and detects the focus error when the lens is out of the normal distance.

In addition, tracking error detection is caused by the eccentricity of the center hole of the optical disk, the track eccentricity, the shaking of the axis of rotation of the turntable, and the like. Therefore, the laser beam is not correctly tracked in order to accurately read and write on the track. You must. The tracking accuracy must be collected within about ± 0.1 μm, and the detection accuracy of the tracking error detection signal is required to be about ± 0.03 μm.

1 is a block diagram of a method for adjusting a servo device of a conventional optical disc player.

As shown, the first step (S10) of adjusting the offset to remove the offset of the focus error and tracking error signal, and by adjusting the direct current bias (BIAS) of the tracking error signal with the offset adjusted in the above, the tracking balance error In the second step S20 of adjusting to within the range and adding the DC bias signal to the focus error signal whose offset is adjusted in the first step S10, the focus balance is adjusted so that the amplitude of the RF signal is maximized. The third step (S30) to adjust to within the error range, and the phase difference between the CLOSE LOOP output signal and the pure disturbance signal by the tracking balance adjustment of the second step (S20) to detect and fall within the predetermined range Phase difference between the fourth loop (S40) of adjusting the tracking gain and the closed loop output signal and the pure disturbance signal by the focus balance adjustment of the third step (S30). The fifth step (S50) of adjusting the focus gain to detect and fall within the predetermined range, and the sixth step (S60) of the RF AGC (Automatic Gain Control) adjustment to correct the change over time of the RF signal. Automatic adjustment of the servo system of the optical disc reproducing apparatus is completed (S70).

However, the above-described servo adjustment method has a problem in that the accuracy of the servo operation state is lowered because the accuracy and accuracy of the adjustment state are low by completing the servo automatic adjustment in one adjustment.

Accordingly, an object of the present invention is to solve the problems described above, and an object of the present invention is to repeatedly adjust the servo adjustment of an optical disc reproducing apparatus, which is performed only once, to maintain the optimum operating state of the servo, thereby improving accuracy. The present invention provides a method for adjusting a servo device of a device.

1 is a block diagram of a servo device adjusting method of a conventional optical disc player;

2 is a block diagram of a servo adjusting device for implementing a servo device adjusting method of an optical disk player according to the related art and the present invention;

3 is a block diagram of a servo device adjusting method of an optical disc player according to the present invention.

Explanation of symbols on the main parts of the drawings

100 optical pickup 110 focusing servo

120: tracking servo 130: control unit

140: spindle servo 150: spindle motor

A servo device adjustment method of an optical disc player according to the present invention for achieving the above object is a first step of adjusting the offset to remove the offset of the focus error and tracking error signal, and the tracking error signal with the offset adjusted A second step of adjusting the tracking balance to within the error range by adjusting the DC bias of the second bias; and adding a DC bias signal to the focus error signal whose offset is adjusted in the first step to adjust the focus balance to maximize the amplitude of the RF signal. A third step of adjusting to within an error range, a fourth step of repeatedly adjusting the tracking balance of the second step, a fifth step of repeatedly adjusting the focus balance of the third step, and tracking Detects the phase difference between the closed loop output signal and the pure disturbance signal by the balance secondary adjustment, and falls within the specified range. A sixth step of adjusting the tracking gain to enter, and a seventh step of adjusting the focus gain to fall within a predetermined range by detecting a phase difference between the closed loop output signal and the pure disturbance signal by the second focus balance secondary adjustment of the fifth step And an eighth step of adjusting the RF AGC for correcting changes over time of the RF signal.

Best Mode for Carrying Out the Invention An embodiment of a servo adjustment apparatus for an optical disc player according to the present invention will be described with reference to the accompanying drawings.

2 is a block diagram of a servo adjustment apparatus for implementing the servo device adjustment method of the optical disk player according to the present invention.

An optical pickup unit 100 for outputting an RF signal and a focus and tracking error signal, a focus servo 110 for detecting a focus error signal and adjusting a difference value, and detecting and adjusting a tracking error signal. A tracking servo 120, a control unit 130 for controlling the focus servo 110 and tracking servo 120 signals, a spindle servo 140 for adjusting the spindle servo based on the result of the control unit 130, It consists of the spindle motor 150 which rotates an optical disc.

In addition, various adjustment steps are performed to adjust the servo device of the optical disc reproducing apparatus.

The above adjustment steps include steps of offset adjustment, tracking balance adjustment, tracking gain adjustment, focus balance adjustment, focus gain adjustment, and RF AGC adjustment.

The offset adjustment is performed by inputting a focus error and tracking error signal to an A / D converter to obtain a positive signal, and a sampling average value obtained by finely sampling the signal and processing the inverted data by using an offset register (REGISTER) and the inverted signal. It is an offset adjustment method that removes an offset by summing positive signals.

The tracking balance adjustment obtains the center value by detecting and adding the maximum and minimum values of the tracking error signal and then averaging them to the set data value. The gain of the tracking signal is adjusted so that this center value is as close as possible to the reference value.

The above tracking gain adjustment inputs a sine wave disturbance signal to the servo closed loop by tracking balance adjustment so that the disturbance signal detects the phase difference between the output signal output through the servo loop and the pure disturbance signal so that the phase difference falls within the predetermined range. Tracking gain adjustment that adjusts tracking gain.

In the above-described focus balance adjustment, the amplitude difference of the RF RIPPLE signal can be measured when defocusing the positive and negative sides of the just on focus. Focus balance adjustment is to adjust the defocus amount so that this amplitude difference becomes 0 (zero). When this amplitude difference becomes 0 (zero), it becomes an adjustment value that maximizes the amplitude of the RF signal.

In the above-described focus gain adjustment, the sine wave disturbance signal is input to the servo closed loop by the focus balance adjustment so that the disturbance signal detects the phase difference between the output signal output through the servo loop and the pure disturbance signal so that the phase difference is within a predetermined range. Focus gain adjustment method that adjusts the focus gain.

The RF AGC adjustment detects the peak value by A / D conversion of the RF ripple signal, and also obtains the RF ripple signal value at the time of focus OFF at the time of offset adjustment and compares the peak value with the peak value. A gain adjustment method that corrects changes over time.

The method of adjusting the servo device of the optical disc reproducing apparatus of the present invention using the above-described several correction methods will be described in detail as follows.

3 is a block diagram of a servo device adjusting method of the optical disk player according to the present invention.

As shown in FIG. 3, in order to remove the offset of the focus error and tracking error signal, the first step S110 is adjusted, and the DC bias of the tracking error signal whose offset is adjusted is adjusted to track the tracking error. In the second step S120 of adjusting the balance to within the error range, and adding the DC bias signal to the focus error signal whose offset is adjusted in the first step S110, the focus balance is adjusted so that the amplitude of the RF signal is maximized. When the tracking balance value is checked after the third step S130 and the third step S310 are adjusted to within the range, the error range is often out of range again. That is, the balance adjustment is adjusted roughly. Therefore, when the second step S120 and the third step S130 are repeatedly adjusted in the roughly adjusted state, fine adjustment is performed.

That is, the fourth step (S140) of repeating the tracking balance to the second within the error range by repeating the tracking balance in the next step, the fifth step (S150) of performing the second adjustment to the second within the error range by repeating the focus balance, and tracking balance 2 The sixth step (S160) of detecting the phase difference between the closed loop output signal and the pure disturbance signal by the difference adjustment and adjusting the tracking gain so as to fall within a predetermined range, and the second step of adjusting the focus balance of the fifth step (S150). The seventh step (S170) of detecting a phase difference between the closed loop output signal and the pure disturbance signal and adjusting the focus gain to fall within a predetermined range, and the final step of adjusting the RF AGC to correct the change over time of the RF signal. If step S180 is performed, automatic adjustment of the servo system of the optical disc reproducing apparatus is completed (S190).

As a result, conventionally, the tracking balance and the focus balance were adjusted only in the error range defined in each block. However, when actually looking at the adjustment value of the tracking balance after adjusting the focus balance, it is slightly out of the preset value. In other words, by repeatedly readjusting the roughly adjusted balance value, accurate balance adjustment can be made, thereby enabling accurate gain adjustment.

In addition, if accurate balancing is not performed even for tracking and focus secondary adjustment, balance adjustment is repeated again.

As described above, the servo device adjustment method of the optical disc player according to the present invention has the effect of improving the accuracy of the servo operation state by increasing the accuracy and accuracy of the adjustment state by repeatedly adjusting the balance adjustment performed only once. .

Claims (2)

Adjusting an offset to remove an offset of the focus error and tracking error signal; A second step of adjusting the tracking balance to within an error range by adjusting a DC bias of the tracking error signal whose offset is adjusted in the first step; A third step of adjusting the focus balance to within an error range so that the amplitude of the RF signal is maximized by adding a DC bias signal to the focus error signal whose offset is adjusted in the first step; A fourth step of repeating the tracking balance of the second step to make second adjustments within an error range; A fifth step of repeatedly adjusting the focus balance of the third step to within an error range; A sixth step of detecting a phase difference between the closed loop output signal and the pure disturbance signal by the second step of adjusting the tracking balance and adjusting the tracking gain to fall within a predetermined range; A seventh step of detecting a phase difference between the closed loop output signal and the pure disturbance signal by the second focus balance second adjustment and adjusting the focus gain to fall within a predetermined range; And A method of adjusting a servo device of an optical disc reproducing apparatus, characterized by performing the eighth step of adjusting the RF AGC for correcting changes over time of the RF signal. The method of claim 1, When the balance secondary adjustment of the fourth step or the fifth step is not satisfied, the balance adjustment is repeated by repeating the fourth step or the fifth step until the predetermined error range is satisfied. Servo device adjustment method of optical disc player.