KR100275875B1 - Track jump control method in defect - Google Patents

Abstract

PURPOSE: A method for controlling a track jump in a defect is provided to compensate a track movement of an optical pickup device when detecting a defect, so as to prevent abnormal disk reproducing due to the defect. CONSTITUTION: Whether sliding to another track due to a disk defect is generated when reproducing data are detected. If so, a pickup is moved to a position before a defect position, and data are reproduced to detect whether data are normally reproduced. Moving and reproducing operations are repeated predetermined number of times(N), until data are normally reproduced. If data are not normally reproduced after the N-moving and reproducing operations, a track jump is performed on the basis of a slid direction and a corresponding track number.

Description

Track Jump Control Method in Defect

The present invention relates to a method for controlling track jump at a defect of a disc, and more particularly, to a track jump control method capable of compensating track movement for track slip of an optical pickup apparatus when a defect is detected.

Optical discs, such as compact discs (hereinafter referred to as CDs) or digital video discs (hereinafter referred to as DVDs), read data from the discs in a non-contact manner using an optical pickup device. The optical pickup apparatus emits a laser to irradiate the disc, receives an optical signal reflected from the disc, and reproduces the disc. Therefore, the error signal included in the read data is minimized only when the spot of the laser irradiated from the optical pickup apparatus accurately tracks the track of the disc on which the information is recorded, and the focus is precisely adjusted at the center of the track.

A process of reading the data recorded on the disc using the optical pickup apparatus will be described with reference to FIG.

Beams emitted from the laser diode 1 are split into three beams through the diffraction grating 2. The beam split into three beams in the diffraction grating 2 passes through a collimator lens 4 which makes a parallel beam through a beam splitter 3. Then, an optical lens 6 passes through an object lens 5 that focuses a beam spot on a pit in which information is recorded.

Through such a path, the beam modulated by the information carrier recorded on the information recording surface of the optical disc 6 is reflected along the same path back to the objective lens, the collimating lens, and the beam splitter. The path of the beam splitter is changed to be collected by a sensor lens 7, and the collected beam is incident to an optical detector 8.

In this case, the photodetector 8 is located at the center of the light receiving unit (A, B, C, D) for receiving the main beam is divided into four. The light receiving units E and F for receiving the auxiliary beam are positioned above and below the main beam.

The electrical signal output from the photodetector 8 of the pickup apparatus 10 configured as described above is a reproducing signal processor which performs predetermined signal processing and amplification so that it can be used as a basic signal for tracking and focusing control and information reproduction. Is approved. The tracking and focusing control signals output from the reproduction signal processing unit are input to the servo unit to perform servo control of the optical pickup apparatus.

In addition, the electrical signal output from the photodetector 8 of the pickup device 10 is output by performing a process such as a predetermined signal compensation and filtering for reproduction. At this time, after the signal processing until the output signal is displayed, it is output to the display device, the user is watching the desired image.

That is, the optical pickup apparatus 10 emits the laser 1 to irradiate the disk 6, and receives the optical signal reflected from the disk 6 by the photodetector 8 to reproduce the disk. Therefore, the spot of the laser 1 irradiated from the optical pickup apparatus 10 accurately tracks the track of the disk 6 on which the information is recorded, and also includes an error that is included in the data to be read only when the focus of the track is correctly adjusted. The signal is minimized.

On the other hand, when the optical pickup apparatus 10 encounters a defect or scratch existing on the disk while reading data while tracking the track of the disk 6, the optical pickup apparatus 10 is currently being tracked. An error may occur in the operation of reading data without departing from the track of the track or the effect of the scratch.

In this case, the operation process will be described with reference to the servo control method of the conventional optical pickup device by the scratch shown in FIG.

When the optical pickup apparatus 10 encounters scratches or defects existing on the disk (step 103) while the optical pickup device 10 controls the servo unit to reproduce data recorded on the disk 6 (step 101), the optical pickup There is no high frequency signal detected from the device 10 or it is detected as a low frequency component compared to the high frequency signal in a steady state. At this time, the servo unit drives the slide motor to move the optical pickup device 10 by a predetermined track movement amount (step 105). Then, the track movement of the optical pickup device 10 will start from the position of the sector address which is the last detected data from the optical pickup device 10.

After a certain amount of movement of the optical pickup apparatus 10 according to step 105, when a high frequency signal is detected from the optical pickup apparatus 10, the position of the detected data is determined. That is, the sector address detected after the optical pickup device 10 is moved and the sector address before the track movement starts in step 105 are judged to determine whether there is continuity of the detected data (step 106). If there is no continuity between the two sector addresses at this time (when the difference in the sector addresses of the two signals is too large), the track slip of the optical pickup device 10 occurs as soon as the scratch passes.

That is, in step 106, it is determined whether track slippage has occurred during the passage of the scratch of the optical pickup apparatus 10.

When it is detected in step 106 that the two sector addresses are consecutive, the track movement through the scratches of the optical pickup device 10 is normally performed. From this time, normal playback of the disc is performed again.

However, when the continuity of the two sector addresses is not detected in step 106, it is determined that the track slip occurs in the optical pickup device due to scratching, and then the pickup device 10 is moved to the position before the scratch detection again. A certain track movement of the pickup apparatus 10 is performed.

The operation is repeatedly performed up to a predetermined number of times as in steps 107 and 109, and each time a single operation is performed, the sector address detected immediately after the track movement for the passage of the scratch and the sector address of the track movement start position are performed. Comparison work is done. However, despite repeating the steps 103 through 109, if the track movement of the optical pickup apparatus 10 does not proceed normally, the system switches to the stop mode and indicates that the disc is not playable (111). step).

In other words, the conventional servo control method of a disc by scratching causes the optical pickup device to track by a predetermined amount in a state where the tracking servo of the optical pickup device is turned off when the scratch is detected from the disk, thereby leaving the scratch range.

However, if the scratches present on the disk are large, the operation of the step 105 cannot compensate for the track movement of the pickup apparatus. In particular, when a certain amount of track movement of the pickup apparatus according to step 105 is made, the pickup apparatus is bounced in one of the inner and outer circumferences of the disc by the tracking balance.

In other words, when there is a large scratch on the disc, an attempt is made to repeat the movement of the track by a certain amount in step 105 to pass through it, but the optical pickup device 10 does not escape the scratch by the movement of the track by the predetermined amount at this time. ) Is a case where the track is constantly off the track in one direction. Therefore, when there is a scratch, even if a continuous track movement of the optical pickup device 10 is continuously attempted, the defects of the same position are continuously met. If this process is repeatedly performed, the system determines that the disc cannot be played.

That is, in the conventional track movement control method, the disc cannot be reproduced due to scratches or defects present on the disc, which causes a problem in that the reliability of the product is deteriorated.

Accordingly, an object of the present invention is to provide a track jump control method in a defect capable of compensating for track movement of an optical pickup apparatus when a defect is detected.

1 is a block diagram of a general optical pickup device.

2 is an operation flowchart for the servo control of the optical pickup device by the conventional scratch.

3 is a block diagram of a track jump control apparatus in the defect according to the present invention;

4 is a flowchart showing a track jump control method in the defect according to the present invention;

Fig. 5 is a state diagram for explaining the track slipping operation of the optical pickup device due to the defect.

* Explanation of symbols for main parts of the drawings

1: laser diode 2: diffraction grating

3: beam splitter 4: collimator lens

5: objective lens 6, 30: disc

7: condenser lens 8: photodetector

10, 34: optical pickup device 32: motor

36: playback signal processing section 38: defect detection section

40: microprocessor 42: memory

44: servo unit 46: digital signal processing unit

A track jump control method in the defect according to the present invention for achieving the above object comprises the steps of: detecting a track jump slipped to another track by a disk defect during a pickup movement; Calculating a slipped direction and the number of jumped tracks when a track jump is generated; And performing additional track jumps based on the direction and the number of tracks.

The track jump control method in the defect of the present invention determines a track slip caused by the defect and proposes a track movement method of the optical pickup apparatus capable of compensating for this. This track jump control method compares the sector address before the track movement with the defect and the sector address after the track movement to determine the number of tracks to which the optical pickup apparatus has moved. Then, the track movement of the optical pickup apparatus is performed by the number of tracks added by 1 to the number of tracks, in which case the track movement is performed in the direction opposite to the direction in which the track slip is generated.

Accordingly, the track jump control method of the present invention recognizes that track slip due to defect is generated in one direction according to the tracking balance of the system, and performs track movement of the optical pickup device in a direction opposite to the track slip direction upon detecting the defect. In this way, the track movement of the optical pickup apparatus is normally performed. Therefore, there is an effect of preventing abnormal disc playback or disc playback impossible due to defects, and normal disc playback.

Hereinafter, with reference to the accompanying drawings, a track jump control method in the defect according to the present invention will be described in detail.

3 is a block diagram of a track jump control apparatus in the defect according to the present invention.

The structure of the track jump control apparatus of the present invention includes a disk 30 for storing various types of data such as video, audio, subtitles, sub-pictures, a motor 32 driven for rotation of the disk 30, and And an optical pickup device 34 for reading data from the disc 30, and a reproduction signal processor 36 for amplifying and outputting the data read out from the optical pickup device 34 by a predetermined amount. In addition, there is a servo unit 44 that controls the driving of the optical pickup device 34 and the motor 32.

That is, the servo unit 44 performs tracking and focusing control of the optical pickup device 34, and also, when detecting defects or scratches to be described in the present invention, out of the range of the defects or scratches. The control of the slide servo which tracks the optical pickup device 34 is also performed.

The optical pickup device 34 receives the tracking and focusing control of the servo unit 44, reads the data recorded on the disk 30, and controls the movement of the track under the control of the slide servo of the servo unit 44. Perform. Since the process up to reading data from the optical pickup device 34 has been described in detail with reference to FIG.

The reproduction signal processor 36 of the present invention inputs the signals A, B, C, and D detected from the optical pickup device 34, and tracks and focuses the optical pickup device 34 based on the signals. And outputs a base signal (A + C)-(B + D) for controlling. In addition, the reproduction signal processing unit 36 performs analog signal processing such as signal compensation and filtering for signal reproduction based on the detected signals A, B, C, and D, and then passes to the digital signal processing unit 46. Output

The digital signal processing unit 46 converts the input analog signal into a digital signal, performs signal processing such as demodulation and error correction, performs primary signal processing for display, and then outputs the signal. At this time, the output signal is displayed after being decoded by a decoder.

In addition, some signals necessary for controlling the reproduction of the disc from the digital signal processed signal by the digital signal processor 46 are applied to the microprocessor 40. In this case, the applied signal is the same as the address of the currently input data. In general, since data is reproduced in sector units in the case of a CD or a DVD, a sector address is detected and applied to the microprocessor 40.

The microprocessor 40 is used to determine the input sector address and to determine the playback position of the current disc 30. The sector address is a reference signal for determining the position of a sector to be played next. Used as At this time, the input sector address is temporarily stored in the memory 42, and the large address is continuously stored in the memory 42 as compared with the next input sector address.

The present invention includes a defect detector 38 for detecting an error caused by scratching or the like of the disc on the basis of the high frequency signal output from the reproduction signal processor 36. The defect detection unit 38 does not output a defect signal when the high frequency signal is normally detected from the disc 30 by the optical pickup device 34. However, when there is a defect or scratch or the like on the disk 30, since the beam emitted from the laser diode 1 is not reflected by the disk normally, the signal detected by the photodetector of the optical pickup device 34 is a low frequency component signal. Becomes At this time, the defect detector 38 outputs a defect signal.

The following describes a track jump control method in the defect according to the present invention.

4 is a flowchart illustrating a track jump control method in the defect according to the present invention. 5 is a state diagram for explaining the track slipping operation of the optical pickup device due to the defect.

When an external input signal for reproducing the disc is input, the microprocessor 40 performs a signal processing for the reproducing of the disc and a control signal for driving the rotation of the disc 30 to the servo unit 44. The data reproduced through the optical pickup device 34 is then subjected to analog signal processing through the reproduction signal processing unit 36 and output to the digital signal processing unit 46. The digital signal processing unit 46 is output after digital signal processing such as demodulation and error correction of input data and displayed on the display apparatus (step 210).

In the signal processing according to the above disc reproducing operation, the data recorded on the disc 30 must be normally read by the optical pickup device 34 so that the signal processing for reproducing the read data is continuously performed and displayed on the display device. do.

However, when there is a defect or scratch on a portion of the disc 30, an error occurs in the track tracking of the optical pickup device 34, and therefore, as the track tracking is misaligned, it is read from the optical pickup device 34. The data is an abnormal signal. When an error occurs in the track tracking of the optical pickup device 34, there is no high frequency signal read from the optical pickup device 34. Therefore, the output signal of the reproduction signal processing unit 36 appears to be cut off. do. At this time, the defect detection unit 38 outputs a defect signal indicating that there is a defect or a scratch on the disk (step 203).

When the defect in step 203 is detected, the microprocessor 40 instructs the servo unit 44 to control the pickup device 34 according to the presence of the defect, and the servo unit 44 of the disc The optical pickup device 34 leaves the defect area out of control. Normally, in this case, the servo unit 44 moves the optical pickup device 34 by a predetermined track movement amount. At this time, the slide servo is driven with the tracking servo that controls the tracking of the optical pickup device 34 off, thereby performing track movement of the optical pickup device 34 (step 205). At this time, the track movement of the optical pickup apparatus 10 will start from the position of the sector address which is the last detected data from the optical pickup apparatus 10. The sector address at this time is stored in the memory 42 under the control of the microprocessor 40.

After a certain amount of movement of the optical pickup device 34 in step 205, when a high frequency signal is detected from the optical pickup device 34, the position of the detected data is determined. That is, by comparing the sector address detected after the optical pickup device 34 moves with the sector address stored in the memory 42 before the track movement starts in step 205, it is determined whether there is continuity of the detected data (step 207). ). If there is no continuity between the two sector addresses at this time (when the difference in the sector addresses of the two signals is too large), the track slip of the optical pickup device 34 occurs when the scratch passes.

That is, in step 207, it is determined whether track slippage has occurred during the passage of the scratch or the defect of the optical pickup device 34. At this time, the track slip of the optical pickup device 34 is generated in the inner circumferential direction around the defect as shown in FIG. 5A or in the outer circumferential direction around the defect as shown in FIG. 5B. This always appears in one direction depending on the system due to the tracking balance of the optical pickup device 34.

Therefore, when it is detected in step 207 that the two sector addresses are continuous, the track movement passing through the scratches of the optical pickup device 34 is normally performed. From this time, normal playback of the disc is performed again.

However, when the continuity of the two sector addresses is not detected in step 207, it is determined that the track slip occurs in the optical pickup device due to scratching, and then the pickup device 34 is moved back to the positions T3 and T4 before scratch detection. In step 205, the pickup apparatus 34 moves a predetermined track.

As described in operations 209 and 211, the operation is repeatedly performed up to a predetermined N times, and the sector addresses T1 and T5 detected immediately after the track movement for the passage of scratches are performed every time one operation is performed. ) And the sector address of the track movement start positions T3 and T4 are made. However, in spite of repeating the N times from steps 203 to 211, if the track movement of the optical pickup device 34 is not normally performed, at this time, the track slip occurs and the microprocessor 40 generates a track slip. To judge.

After the track slip is determined after performing the step 211, the optical pickup device 34 calculates how much track slip occurs in which direction due to defect or scratch (step 213).

That is, in the case of Fig. 5A, the position of the sector read last from the optical pickup device 34 before the defect detection is T3. That is, when the track movement for passing the defect at the position of T3 is performed, the track slip of the optical pickup device 34 due to the defect is generated and the position where the movement is made becomes the position of T1. Therefore, when comparing the position T3 before the track movement and the position T1 after the track movement in step 207, it can be seen that the pickup device 34 has slipped two tracks in the inner circumferential direction.

Similarly, in the case of Fig. 5B, the sector address read last from the optical pickup device 34 before the defect detection is T4. When the track movement for passing through the defect is performed from the position of T4, the position where the optical pickup device 34 is moved due to the track slip becomes the position of T5. Therefore, the microprocessor 40 can recognize that the track in which the pickup device 34 has slipped two tracks in the circumferential direction by comparing the sector addresses of T4 and T5.

As described above, in step 213, the pickup device 34 may know the direction S in which the pickup device slips, and the number of tracks Q that are slipped. The microprocessor 40 controls the servo unit 44. A control command is applied to move the track Q + 1 in which the one track is added to the slipped track number Q in the direction D 'opposite to the slipped direction. Subsequently, under the control of the servo unit 44, the optical pickup device 34 moves the track in the direction opposite to the direction where the slip is generated at the initial positions T3 and T4 where the defect is detected and by the number of tracks Q + 1. (Step 215).

Accordingly, the optical pickup apparatus will be moved to the position of T2 by making three track jumps in the outer circumferential direction in FIG. 5A, and moving to the position of T6 by making (2-1) track jumps in the inner circumferential direction in FIG. 5B.

After the track movement of the optical pickup apparatus 34 is performed by the above process, the optical pickup apparatus 34 will be free from the influence of the defect, and then the disc reproducing operation is normally performed again.

As described above, in the track jump control method for defects according to the present invention, when a large defect or scratch is present on a disc, the optical pickup device moves in one direction of the inner or outer circumference of the disc as soon as it passes over the defect. Use it to bounce off. In other words, if the track movement of the optical pickup apparatus is continuously controlled by the same method, the optical pickup apparatus continuously encounters the defect at the same position on the disk, and if such an operation is repeated, the system recognizes that the playback is impossible. Therefore, in order to eliminate the impossibility of playing the disc due to the defect or the like, when the optical pickup device continues to bounce in one direction due to the defect, the track movement of the optical pickup device 34 is controlled in the opposite direction to this popping out direction. At this time, the number of tracks to be moved is characterized by moving as much as the number of tracks by adding 1 to the number of tracks moved when bounced.

That is, the track jump control method of the present invention according to the present invention recognizes that the track slip caused by the defect is generated in one direction according to the tracking balance of the system, and the optical pickup device is moved in the opposite direction to the track slip direction when the defect is detected. The track movement of the optical pickup apparatus is normally performed by performing track movement of the optical pickup apparatus. Therefore, there is an effect of preventing abnormal disc playback or disc playback impossible due to defects, and normal disc playback.

Claims (1)

A first step of detecting whether the data slips on another track due to a disc defect during data reproduction; A second step of, if slipped, moving the pickup to a position before the defective position and performing data reproduction to detect whether normal data reproduction is performed; A third step of repeating the movement and playback operations a predetermined number of times until the normal playback is performed in the second step; And a fourth step of performing track jump on the basis of the sliding direction and the number of tracks when normal playback is not possible even after repeating N times in the third step.

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