KR100271568B1 - Method of detecting and controlling shock of optical disk and device thereof - Google Patents

Abstract

PURPOSE: A method for detecting and controlling a shock of an optical disk and a device thereof, are provided to use a tracking error and wobble frequency, so as to correctly detect a shock of the optical disk and perform corresponding control. CONSTITUTION: A wobble frequency detector(12) detects a tracking error signal in a reproducing signal from a pre-amplifier(8), and outputs a wobble signal detected by band pass filtering the tracking error signal. A wobble frequency comparison/shock detection unit(30) compares a frequency of the wobble signal from the wobble frequency detector(12) with a reference frequency. If the compared signals are not equal, the wobble frequency comparison/shock detection unit(30) outputs a shock detection signal to a data processor(14) and a servo processor(16). The servo processor(16) recognizes the generation of a shock of an optical disk(2), by the shock detection signal from the wobble frequency comparison/shock detection unit(30). If the generation of a shock is recognized, the servo processor(16) searches a zone where the shock is generated by information from the data processor(14). And the servo processor(16) controls a sled driver(18) using a distance between a moving position and an original position, and moves a sled to the original position, to restore a focus of optical beam irradiated on the optical disk(2) from am optical pickup(6) to an original position at a high speed.

Description

Optical disc shock detection and control method and apparatus

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for recording / reproducing an optical disc in which a wobbling signal is preformatted, and more particularly, to an optical disc shock detection and control method capable of quickly and accurately detecting and controlling shock when an optical disc occurs during reproduction. will be.

The accuracy of the servo technology plays a very important role in determining the accuracy when recording and reproducing information on an optical disc, which has recently been spotlighted as an information recording medium. In the conventional optical disc, since only the information already recorded by the mastering device needs to be properly read, a relatively accurate servo is not required. Recently, however, optical discs capable of both recording and reproducing such as Compact Disc-Recordable (CD-R) and Digital Versatile Disc-Random Access Memory (DVD-RAM) have been developed. Accordingly, a more accurate servo technique is required at the time of recording. In addition, it is preferable to apply a servo method with better performance in the existing regeneration method for the stable acquisition of the signal.

On the other hand, when a shock occurs when reproducing information from an optical disc in a conventional optical recording / reproducing apparatus, an actuator or sled may move. At this time, the optical recording / reproducing apparatus has an algorithm that determines whether a shock is generated using a tracking error signal and returns the optical pickup to the original track using the speed component of the spindle servo. However, the conventional optical disc shock detection and control method has a disadvantage in that it takes a lot of time for accurate shock detection and corresponding control. These drawbacks will become apparent by looking at the process of detecting and controlling shock when a shock occurs when reproducing information from a wobbling DVD-RAM in a conventional optical recording / reproducing apparatus through the accompanying drawings.

1 shows a configuration of an optical recording / reproducing apparatus for general optical disk shock detection and control. The optical disk shock detection and control apparatus shown in FIG. 1 includes a spindle motor 4 for rotating the optical disk 2, and an optical disk. An optical pickup 6 for reproducing information from (2), a pre-amplifier 8 for amplifying and waveform shaping a reproduced signal from the optical pickup 6, and a high frequency signal in the output signal of the preamplifier 8; An RF detector 10 for detecting a (RF) signal, a wobble frequency detector 12 for detecting a frequency (ie, a wobble frequency) of a tracking error signal, a wobble signal, and a wobble signal from an output signal of the preamplifier 8; And a data processor 14 for decoding the RF signal from the RF detector 10 and the wobble signal from the wobble frequency detector 12, and a host computer 24 for receiving the decoded signal of the data processor 14. Then, the optical disk shock of FIG. The detection and control device recognizes whether a shock is generated by the tracking error signal from the wobble frequency detector 12 and controls the sled driver 18 and the spindle driver 22 through the information of the data processor 14. It includes a servo processor 16 and a sled motor 20 driven by the sled driver 18 to transport the sled of the optical pickup 6.

In the optical disk shock detection and control apparatus of FIG. 1, the optical pickup 6 scans a laser beam onto an optical disk 2 that is rotated by the power of the spindle motor 4, and converts the optical beam reflected by the optical beam into an electrical signal. It outputs to the preamp 8. The preamplifier 8 performs current-voltage conversion, amplification, waveform shaping, and outputs the reproduction signal output from the photodetector of the optical pickup 6 to the RF detector 10 and the wobble frequency detector 12. The RF detector 10 detects an RF signal from the output signal of the preamplifier 8 and outputs the RF signal to the data processor 14. The wobble frequency detector 12 detects a tracking error signal from the output signal of the preamplifier 8 and outputs it to the servo processor 16. In addition, the wobble frequency detector 12 outputs the wobble signal detected by bandpass filtering the tracking error signal to the data processor 14. The data processor 14 decodes and error-corrects the RF signal of the RF detector 10 and outputs it to the host computer 24, and decodes the wobble signal from the wobble frequency detector 12 to control the rotational speed of the spindle motor. .

In other words, in normal operation, the data processor 14 controls the spindle driver 22 through the servo processor 16 so that the spindle motor 4 is driven in a CLV (Constant Liner Velocity) manner. Referring to Fig. 2, the speed change of the spindle motor by the Zoned-CLV control method, which is one of the spindle controls used for the DVD-RAM disc, is shown. This makes the playback speed of data read out from each zone constant by varying the spindle speed in all zones of the DVD-RAM disc. To this end, the data processor 16 controls the speed of the spindle motor fast on the inner disk and slow on the outer disk.

By the way, when a large shock occurs in the optical disc 2, an actuator or sled of the optical pickup 6 is moved to cause the focus of the light to move to another zone on the optical disc. At this time, the tracking error signal is detected by the wobble frequency detector 12 from the reproduction signal detected by the optical pickup 6 via the preamplifier 8 and output to the servo processor 16. The servo processor 16 recognizes the shock generation of the optical disc by the tracking error signal of the wobble frequency detector 12 and performs servo system control corresponding thereto.

3 and 4, the spindle speed variation characteristic and the sled position variation characteristic by the conventional optical disk shock detection and control method are shown.

When the shock of the optical disc is detected by the tracking error signal in the servo processor 16 (b), the spindle speed is controlled by controlling the spindle driver 22 to return the optical pickup 6 moved by the shock to its original position. Increment or decrease (c) detect the location of movement by shock, i.e. the zone (d and e). Subsequently, the servo processor 16 controls the sled driver 18 through the information from the data processor 14 (f) moves the sled to its original position (g), and also drives the spindle driver 22. By controlling, the speed of the spindle motor 4 is corrected (f) and returned to the original speed (g).

As described above, the conventional optical disk shock detection and control apparatus determines whether shock is generated by using a tracking error signal detected when a shock occurs while reproducing information from the optical disk, and uses the speed component of the spindle servo to perform optical pickup. Return to the track. However, the conventional optical disc shock detection and control method consumes a lot of time for accurate shock detection and corresponding control.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to provide a shock detection and control method and apparatus for an optical disc capable of promptly detecting and correspondingly controlling when a shock occurs.

It is another object of the present invention to provide a shock detection and control method and apparatus for an optical disc that can quickly detect an optical disc shock and control corresponding thereto by using a tracking error and wobble frequency.

1 is a block diagram showing the structure of a conventional optical disk shock detection and control apparatus.

2 is a characteristic diagram showing a change in spindle speed of the Zoned-CLV spindle control method.

3 is a characteristic diagram showing a change in spindle speed by a conventional optical disc shock detection and control method.

4 is a characteristic diagram showing a change in spindle speed by a conventional optical disc shock detection and control method.

5 is a block diagram showing an optical disk shock detection and control device according to the present invention;

6 is a characteristic diagram showing a change in wobble frequency by the optical disk shock detection and control method of the present invention.

7 is a characteristic diagram showing a change in the sled position by the optical disk shock detection and control method of the present invention.

8 is a flowchart for explaining an optical disk shock detection and control method according to the present invention.

* Explanation of symbols for main parts of the drawings

2: optical disk 4: spindle motor

6: optical pickup 8: preamplifier

10: RF detector 12: wobble frequency detector

14: data processor 16: servo processor

18: sled driver 20: sled motor

22: spindle driver 24: host

30: wobble frequency comparison and shock detector

In order to achieve the above object, an optical disc shock detection and control method according to the present invention comprises: a first step of detecting a tracking error signal from a reproduction signal of an optical disc; Detecting a wobble frequency from the tracking error signal; A third step of detecting whether an optical disc shock is generated depending on whether the frequency of the wobble signal is equal to an arbitrary reference frequency; And a fourth step of returning the servo to the original position by adjusting the servo system using the movement position and the original position when the shock detection is recognized.

The optical disc shock detection and control apparatus according to the present invention further includes optical pickup means for reproducing information from the optical disc; Wobble frequency detecting means for detecting frequencies of the tracking error signal, the wobble signal, and the wobble signal in the reproduction signal from the optical pickup means; Data processing means for decoding the wobble signal from the wobble frequency detecting means; Shock detection means for detecting whether or not an optical disc shock is generated based on the frequency of the wobble signal from the wobble frequency detection means; Servo means for performing servo; And servo processing means for controlling the servo means based on the information from the data processing means in accordance with the output signal of the shock detecting means.

An optical disc shock detection and control apparatus according to the present invention includes a high frequency signal detection means for detecting a high frequency signal from a reproduction signal of an optical pickup means, and a high frequency signal detection means and a wobble frequency by current-voltage conversion of the reproduction signal from the optical pickup means. An output pre-amp for supplying to the detection means is further included.

The above and other objects and advantages of the present invention will become more apparent from the following detailed description of embodiments of the present invention.

First of all, the present invention accurately detects shock by using a point where a wobble frequency (i.e., 157 kHz) is constant in all parts of a disc together with a tracking error signal in shock detection of an optical disc, and the relative position even in restoration to the original position. By using the variable speed of the servo meter to restore quickly.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 5 to 8.

5 is a block diagram showing the configuration of an optical disk shock detection and control apparatus according to an embodiment of the present invention. The optical disk shock detection and control device shown in FIG. 5 includes a spindle motor 4 for rotating the wobbling DVD-RAM optical disk 2, an optical pickup 6 for reproducing information from the optical disk 2, and an optical pickup. A preamplifier 8 for current-to-voltage conversion and amplification of the reproduction signal from (6), an RF detector 10 for detecting an RF signal from the output signal of the preamplifier 8, and an output signal of the preamplifier 8; The wobble frequency detector 12 detecting the tracking error signal, the wobble signal, and the frequency thereof, the wobble frequency comparison and the shock detector 30 detecting the shock by using the frequency of the wobble signal from the wobble frequency detector 12; And a data processor 14 which decodes the RF signal from the RF detector 10 and the wobble signal from the wobble frequency detector 12 and recognizes the shock from the shock detector 30.

In addition, the optical disk shock detection and control apparatus of FIG. 5 controls a tracking servo (not shown) in dependence on the tracking error signal detected by the wobble frequency detector 12, and compares the wobble frequency and the shock detection of the shock detector 30. Servo processor 18 for controlling the sled driver 18 and the spindle driver 22 by the information from the data processor 12 by recognizing the occurrence of shock through a signal, and the driving of the sled driver 18. And a host computer 24 for receiving the decoded data of the data processor 14.

5, a wobble frequency comparison and shock detector 30 is further provided as compared to the optical disk shock detection and control device shown in FIG. This is to make the shock detection of the optical disc and the corresponding servo more accurate and faster by using the tracking error signal and the wobble signal.

8 is a flowchart for explaining an optical disk shock detection and control method according to an embodiment of the present invention. The flowchart of FIG. 8 will be described in detail in conjunction with the apparatus shown in FIG. 5.

When the information is reproduced, the optical pickup 6 reproduces the information from the optical disc 2 rotated in the Zoned-CLV method by the spindle motor 4 and outputs the reproduced signal to the preamplifier 8. The preamplifier 8 amplifies and waveform-forms the reproduction signal from the optical pickup 6 and supplies it to the RF detector 10 and the wobble frequency detector 12 (first step).

The wobble frequency detector 12 detects the tracking error signal from the reproduction signal from the preamplifier 8 and supplies the tracking error signal to the servo processor 16. The wobble frequency detector 12 also detects the wobble signal detected by band pass filtering the tracking error signal. 14) and the wobble frequency comparison and output to the shock detector 30 (steps 2 to 4). The wobble frequency detector 12 may also detect the frequency of the wobble signal and supply the detected wobble frequency to the wobble frequency comparison and the shock detector 30. The wobble frequency comparison and shock detector 30 compares the frequency of the wobble signal from the wobble frequency detector 12 with a reference frequency, that is, a frequency of 157 kHz, and outputs a shock detection signal if it is not equal to the data processor 14 and the servo processor. Output to step 16 (steps 5 and 6).

The servo processor 16 recognizes whether or not the optical disc is shocked by the wobble frequency comparison and the shock detection signal from the shock detector 30 (step 7).

When the occurrence of the shock is recognized in the seventh step, the servo processor 16 finds out which zone the frequency due to the shock belongs to through the information from the data processor 14, and calculates the mutual distance between the movement position and the original position. Control the sled driver 18 to move the sled to its original position, or to vary the actuator gain of the optical pickup 6 to increase or decrease (not shown), thereby removing it from the optical pickup 6. The focus of the light beam irradiated on the optical disc 2 is returned to its original position at high speed (steps 8 and 9).

FIG. 6 is a characteristic diagram illustrating a wobble frequency change by the optical disc shock detection and control method according to an exemplary embodiment of the present invention. When the shock occurs, the wobble frequency is changed and has a constant value when returned to normal operation.

7 is a characteristic diagram illustrating a change in the position of the sled by the optical disk shock detection and control method according to the embodiment of the present invention.

As described above, the optical disk shock detection and control method and apparatus according to the present invention have an advantage that the optical disk shock generation and the corresponding servo control can be accurately and quickly using the wobble frequency during information reproduction.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (11)

A wobbled optical disc recording / reproducing apparatus, comprising: a first step of detecting a tracking error signal from a reproduction signal of the optical disc; Detecting a frequency of a wobble signal from the tracking error signal; Detecting a frequency of the wobble signal from an arbitrary reference frequency; And a fourth step of returning the servo to the original position by varying the servo system speed by using the movement position and the original position when the shock detection is recognized. The optical disk shock detection and control method according to claim 1, wherein the re-stage 2 includes bandpass filtering the tracking error signal to detect a wobble signal and provide a frequency of the detected wobble signal. The optical disc shock detection and control method according to claim 1, wherein the fourth step accurately detects a movement position due to shock using the wobble signal. The optical disc shock detection and control method according to claim 1, wherein the fourth step varies the gain of the sled servo or the actuator. An optical recording / reproducing apparatus for reproducing information from a wobbled optical disc, comprising: optical pickup means for reproducing information from the optical disc; Wobble frequency detecting means for detecting a frequency of a tracking error signal, a wobble signal, and a wobble signal in a reproduction signal from said optical pickup means; Data processing means for decoding the wobble signal detected by the wobble frequency detecting means; Shock detection means for detecting whether an optical disc shock is generated based on a frequency of a wobble signal from said wobble frequency detection means; Servo means for performing servo; And servo processing means for controlling the servo means based on the information from the data processing means in accordance with an output signal of the shock detecting means. 6. The apparatus according to claim 5, further comprising: high frequency signal detection means for detecting a high frequency signal in a reproduction signal from said optical pickup means; And a pre-amplifier for current-voltage converting the reproduction signal from said optical pickup means and outputting it to said high frequency detection means and wobble frequency detection means. 6. The optical disc shock detection and control apparatus according to claim 5, wherein the wobble detection means detects the wobble signal and its frequency by bandpass filtering the tracking error signal. 6. The optical disc shock detection device according to claim 5, wherein the shock detection means determines whether a shock is generated by comparing the wobble frequency from the wobble detection means with a reference frequency according to whether or not both frequencies coincide. 6. The servo processing means according to claim 5, wherein the servo processing means finds a moving position from the data processing means according to the shock detection signal from the shock detecting means, and varies the speed of the servo means by using a mutual distance from the original position. Optical disk shock detection and control device, characterized in that to return to the original position. 10. The optical disc shock detection and control apparatus according to claim 9, wherein the servo processing means returns the position of the light beam to the original position by varying the gain of the sled servo or the actuator. 6. The apparatus of claim 5, wherein the servo means comprises: a spindle motor for rotating the optical disk; A sled motor for transporting the sled of the optical pickup; Sled motor driving means for driving the sled motor under the control of the servo processing means; Spindle motor driving means for driving the spindle motor under the control of the servo processing means; Optical disc shock detection And control device.

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