KR100345234B1 - An apparatus and method for detecting axial vibration - Google Patents

Abstract

The present invention relates to a method and apparatus for detecting and compensating for vibration of a disk surface caused by rotation of a recording medium in recording or reproducing data on a disk-type rotating recording medium. The surface vibration compensation method includes: a first step of rotating the optical disc in a state in which an active state of a focusing servo and an optical pickup are located on an inner circumference of the optical disc; A second step of detecting a voltage value and a center voltage value corresponding to the magnitude of a focusing drive signal output according to the rotational drive of the optical disk; A third step of performing the second step after moving the optical pickup from the inner circumference to the outer circumference of the optical disc; A fourth step of detecting an amount of surface vibration of the optical disk based on the voltage values detected from the second and third steps; And a fifth step of variably setting an operating characteristic of the servo system before regeneration of the optical disc to compensate for the detected surface vibration amount, thereby detecting a degree of surface vibration of the optical disc before regeneration and thereby performing a compensation operation. As a result, it is a useful invention that normal reproduction can be performed without errors even for abnormal discs.

Description

An apparatus and method for detecting axial vibration of an optical disk

The present invention relates to a method and apparatus for detecting and compensating for vibration of a disk surface caused by rotation of a recording medium in recording or reproducing data on a disk-type rotating recording medium.

With the development of technology, disc-type recording media are widely used. In particular, various types of discs such as CD, DVD, or magneto-optical disc (MOD) are being used with increasing recording density. Manufacture.

Such optical discs or magneto-optical discs (hereinafter referred to as 'optical discs') are due to inherent factors such as manufacturing process errors, manufacturing process deviations, or acquired factors due to distribution and user's carelessness. This causes the disk to bend or twist up and down.

In the case of reproducing a recording signal from an optical disk having such a defect, surface vibration occurs due to a deviation of the inner and outer circumference heights of the disk due to the deflection of the disk, and this surface vibration component occurs beyond the allowable range or the disk Skew may be bent in the radial direction due to the bending of the disc. In this case, the disc does not play at all or in severe cases, because the correct focusing and tracking operations are not performed during disc playback. There was a problem of not being.

Conventionally, in order to prepare for the surface vibration of such a disk, the surface vibration component during one rotation of the disk is detected during initial loading of the disk, and from this, radial adjustment, defocus control, etc., are performed before the optical disk is played. Compensation operation was performed. As shown in Figs. 1A to 1C, in the case of a disc bent up and down, the surface vibration at the inner and outer circumferences of the disk is accurately detected even though the surface vibration components at the inner and outer circumferences of the disk are different. If not, there was a problem that the compensation operation according to the surface vibration detection is meaningless.

Accordingly, the present invention has been made to solve the above problems, and provides an apparatus and method for compensating surface vibration of an optical disk for normal reproduction of the optical disk even when surface vibration occurs from an abnormal optical disk. The purpose is.

1A to 1C show the shape of an optical disk bent in a radial direction,

Figure 2 shows the configuration of a preferred embodiment of the optical disk drive device in which the surface vibration compensation device of the optical disk according to the present invention is implemented,

Figure 3 shows the flow of a preferred embodiment of the surface vibration compensation method of the optical disk according to the present invention,

4 shows the shape of a low-pass focused driving signal (FDO signal),

Fig. 5 shows an example of the surface vibration detection position of the optical disk.

※ Explanation of code for main part of drawing

10: optical disc 20: optical pickup

30: R / F 40: Servo part

50 driver 60 digital signal processing

70: low pass filter 80: size detection unit

81: center voltage detector 90: microcomputer

M1: Sled Motor M2: Spindle Motor

Surface vibration compensation device for an optical disk according to the present invention for achieving the above object, the drive means for rotating the optical disk; Reading means for detecting a recording signal on the optical disc; Servo means for performing focusing and tracking servo of said reading means on said rotating drive optical disk; And detecting the surface vibration amount of the optical disk based on a voltage value and a center voltage value corresponding to the magnitude of a focusing driving signal applied by the servo means to the reading means in the inner and outer circumferences of the optical disk. Characterized in that it comprises a control means for variable setting the operating characteristics of,

In addition, the method for compensating the surface vibration of an optical disk according to the present invention includes: a first step of rotating the optical disk in a state where an active state of a focusing servo and an optical pickup are located on an inner circumference of the optical disk; A second step of detecting a voltage value and a center voltage value corresponding to the magnitude of a focusing drive signal output according to the rotational drive of the optical disk; A third step of performing the second step after moving the optical pickup from the inner circumference to the outer circumference of the optical disc; A fourth step of detecting an amount of surface vibration of the optical disk based on the voltage values detected from the second and third steps; And a fifth step of variably setting an operating characteristic of the servo system before reproduction of the optical disk to compensate for the detected surface vibration amount.

Hereinafter, a preferred embodiment of the surface vibration compensation device and detection method for an optical disk according to the present invention will be described with reference to the accompanying drawings.

Fig. 2 shows the configuration of a preferred embodiment of the optical disk drive apparatus in which the surface vibration compensator of the optical disk according to the present invention is implemented, comprising: an optical pickup 20 for reading recorded data on the optical disk 10; An R / F unit 30 for filtering the signal detected by the optical pickup 20 and outputting it as a binary signal; A servo unit (40) for controlling the driving of the drive unit (50) from the tracking error (T.E) and focus error (F.E) signals of the optical pickup (20) and the rotational speed of the optical disc (10); A sled motor (M1) for horizontally moving the optical pickup (20); A spindle motor (M2) for rotating the optical disk (10) in accordance with a control signal output from the servo unit (40); A driver (50) for driving the sled motor (M1) and the spindle motor (M2); A digital signal processor (60) for restoring the binary signal to original data with its own clock synchronized with the binary signal; A low pass filter (LPF) 70 for band filtering a focusing drive (FDO) signal applied to an actuator of the optical pickup 20; A magnitude detector (80) for detecting a voltage value for a difference between a maximum value and a minimum value of a focusing drive signal output from the low pass filter (70); A center voltage detector (81) for detecting a center voltage value of the focusing driving signal; And a microcomputer 90 for detecting the surface vibration amount (or skew) of the optical disk 10 based on the detected positive voltage value and performing a compensation operation.

Figure 3 shows the flow of a preferred embodiment of the surface vibration compensation method of the optical disk according to the present invention, hereinafter will be described in detail with respect to the detection method of Figure 3 according to the present invention with reference to the configuration of FIG.

First, when the optical disk 10 is inserted and seated (S10) in a tray (not shown) provided in the optical disk driving apparatus, the microcomputer 90 is the servo unit 40 and the drive unit 50. By applying a drive voltage to the spindle motor (M2) through the initial rotation of the optical disk 10, the optical disk 10 is brought into a reproducible state almost similar to the CLV (Constant Linear Velocity) on state.

In addition, the microcomputer 90 moves the optical pickup 20 to the inner circumference of the optical disk 10 in order to easily detect whether or not surface vibration is generated from the optical disk 10 (S11). The optical pickup 20 detects a recording signal from a current position of the optical disk 10, wherein the microcomputer 90 is positioned of an objective lens provided in an actuator of the optical pickup 20. The focusing servo operation and the tracking servo operation to variably control are turned on.

In such an operation state, the low pass filter 70 low-passes a focusing driving signal (FDO signal: Focusing Driving Out signal) output from the servo unit 40 to remove high frequency noise, and then receives a signal used only for focusing driving. An example of the signal form is shown in FIG. When the driving signal as shown in FIG. 4 is detected, as shown in FIG. 1, when the rotating disk is bent in the radial direction, the distance between the objective lens and the disk is changed according to the rotation of the disk. This is because the controller outputs a control signal according to a change in distance from the disk to follow this.

The magnitude detector 80 detects the difference between the maximum value (rising peak) and the minimum value (falling peak) of the focus driving signal output by removing the high frequency noise, that is, the voltage value V1 with respect to the signal size. The voltage detector 81 detects the center voltage value V2 of the focusing driving signal (S12).

Subsequently, the microcomputer 90 moves the optical pickup 20 to the outer periphery of the optical disk 10 (S13), and focusing driving signals from the focusing driving signals output from the low pass filter 70 as described above. The voltage value V3 and the center voltage value V4 of the focusing driving signal are respectively outputted for the size of (S14).

As such, when the voltage values V1 and V3 and the center voltage values V2 and V4 for the magnitudes of the focusing driving signals in the inner and outer circumferences of the optical disk 10 are detected, the microcomputer 90 detects the detected V1. The larger of V3 and V3 values is stored as V5 value, the absolute value of the difference between V2 and V4 values is stored as V6 value, and the larger of V5 and V6 values is stored as V7 value.

When the V7 value is finally obtained, the microcomputer 90 detects the surface vibration amount from the obtained V7 value (S15). When the detected surface vibration amount is more than the allowable range (S20), the surface vibration is compensated. In order to calculate the servo gain value corresponding to the V7 value.

The microcomputer 90 applies the calculated servo gain value to the servo unit 40 to perform the focus and tracking servo operation by the applied servo gain value (S21) to the optical disc 10. Even if the surface vibration exceeds the allowable range, normal regeneration can be achieved.

When the reproduction of the optical disc 10 starts, the R / F unit 30 filters the high frequency signal detected by the optical pickup 20 and the digital signal processing unit 60 performs the R / F unit 30. By reproducing and outputting a high frequency signal input from the digital signal processing, the reproducing operation of the optical disc 10 is performed under the operation control of the microcomputer 90.

In the above-described surface vibration detection method, the microcomputer 90 performs the surface vibration detection positions as the inner circumference, the middle circumference, and the outer circumference, respectively, and compares the widths of the respective focusing ranges to determine the radial skew of the disc. Can be.

When the skew level of the disk is known as described above, a compensation operation is performed for each local part of the disk region.

If the detected surface vibration amount is within the allowable range in the above-described detection process (S15), the microcomputer 90 determines the optical disk 10 as a disk capable of normal reproduction, and performs the compensation operation as described above. The playback operation of the disc is immediately started without performing (S22).

The surface vibration compensating apparatus and method for detecting an optical disk according to the present invention, which is configured as described above, detect the surface vibration degree of the optical disk before reproducing and thereby perform a compensation operation, thereby allowing a normal disk to be reproduced normally without errors. This is a useful invention to be made.

Claims (6)

In the optical disk playback method, A first step of rotating the optical disc in a state where an active state of a focusing servo and an optical pickup are located on an inner circumference of the optical disc; A second step of detecting a voltage value and a center voltage value corresponding to the magnitude of a focusing drive signal output according to the rotational drive of the optical disk; A third step of performing the second step after moving the optical pickup from the inner circumference to the outer circumference of the optical disc; A fourth step of detecting an amount of surface vibration of the optical disk based on the voltage values detected from the second and third steps; And And a fifth step of variably setting an operating characteristic of the servo system before reproducing the optical disk to compensate the detected surface vibration amount. The method of claim 1, In the fifth step, the gain of the focusing servo is variably set according to the detected amount of surface vibration. The method of claim 1, In the fifth step, the gain of the tracking servo is variably set according to the detected amount of surface vibration. The method of claim 1, The fourth step, the surface vibration compensation method of the optical disk, characterized in that for detecting the vibration amount based on the difference between the detected positive voltage value. Drive means for rotating the optical disk; Reading means for detecting a recording signal on the optical disc; Servo means for performing focusing and tracking servo of said reading means on said rotating drive optical disk; And The surface vibration amount of the optical disk is detected based on a voltage value and a center voltage value corresponding to the magnitude of a focusing driving signal applied by the servo means to the reading means in the inner and outer circumferences of the optical disk. An apparatus for compensating surface vibration of an optical disk, comprising control means for varyingly setting operating characteristics. The method of claim 5, And the control means adjusts a signal gain value of the servo means in accordance with the detected surface vibration amount.