KR19990026836A - Track Jump Control Method of Optical Disc System - Google Patents

Abstract

A track jump control method of an optical disk system for jumping an optical pickup unit to a target track on a disk, the method comprising: a first step of performing servo control based on an initial servo gain and a servo offset value during normal playback; Calculating a track jump distance from a current playback position on the disc to a target track when the target track is determined in the track jump mode; Detecting a servo gain and a servo offset value set corresponding to the calculated track jump distance; A fourth step of jumping the optical pickup unit to a target track; A fifth step of, after the optical pickup unit reaches the target track, performing servo control based on the servo gain and servo offset values detected in the third step for a preset time; In the fifth step, after the predetermined time elapses, a sixth step of performing servo control based on the initial servo gain and the servo offset value is included.

Description

Track Jump Control Method of Optical Disc System

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a track jump control method for jumping an optical pickup unit to a predetermined track position on a disc in an optical disc system.

In general, an optical disc system is a system for non-contact reproduction of information engraved on a disc by a laser beam and digital signal processing. One of the main features of such an optical disc system is random access to a playback position on a disc. Can be done. Therefore, in the optical disc system, even when playing a track in which a predetermined song is recorded, when a signal for instructing playback of another song is input, the optical disc system immediately searches for the start position of the track in which the song corresponding to the instruction signal is recorded. It is equipped with a function to enable playback.

Such a function is commonly referred to as a track search function. The track jump device is a track jump device that substantially performs the track search function. The track jump device will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a schematic diagram of an optical pickup unit that reads information on a disc by a laser beam and converts the information into an electrical signal. FIG. 2 is a schematic diagram of a track jump apparatus for performing track search. Shown.

In Fig. 1, a predetermined sequence of information is recorded on a disc 10 along a track, and the optical pickup unit 20 emits a laser beam focused by the objective lens 21 on the track of the disc 10. Then, by receiving the light reflected from the track of the disk 10 and converts it into an electrical signal, it serves to read the information recorded on the disk.

On the other hand, in reading out the information recorded on the disk, the disk 10 is actually in a rotating state, and the optical pickup unit 20 is to trace the track of the rotating disk.

Referring to FIG. 2, the error detector 30 generates and outputs a pulse corresponding to each time the optical pickup unit 20 crosses a track without tracing a track of the disc 10. The counter 40 counts the number of pulses output from the error detector 30 and provides it to the microcomputer 50, and the microcomputer 50 can know the crossing distance of the optical pickup unit 20 based on the count value. Therefore, even when the optical disc system is performing normal playback, when an instruction signal for jumping the optical pickup unit 20 to a predetermined position on the disc 10 is input, the microcomputer 50 controls the driver 60 to pick up the optical pickup. After the unit 20 is jumped to a predetermined position, the optical pickup unit 20 determines the jump position by referring to the count value generated in the process of traversing the track of the disk 10, and then the optical pickup unit 20 When the indicated predetermined position is reached, the track jump operation is completed, and then the standby state is maintained for a predetermined time, and then a subsequent operation, for example, a reproduction operation is performed.

Here, the reason for waiting for a predetermined time after completion of the track jump is as follows. That is, after the optical pickup unit 20 completes the track jump operation, the system is in an unstable state due to the instantaneous flow of the optical pickup unit 20. Therefore, the system has stabilized the system with a certain waiting time and resumes normal playback.

However, in the related art, since the system waits until the system is stabilized and regenerates, there is a problem in that a slight time delay occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a track jump control method for shortening the time for stabilization of a system after completion of a track jump so that normal playback can be performed more quickly.

SUMMARY OF THE INVENTION The present invention provides a track jump control method for an optical disc system in which an optical pickup unit is jumped to a target track on a disc in order to achieve the above object. step; Calculating a track jump distance from a current playback position on the disc to a target track when the target track is determined in the track jump mode; Detecting a servo gain and a servo offset value set corresponding to the calculated track jump distance; A fourth step of jumping the optical pickup unit to a target track; A fifth step of, after the optical pickup unit reaches the target track, performing servo control based on the servo gain and servo offset values detected in the third step for a preset time; In the fifth step, after the predetermined time elapses, a sixth step of performing servo control based on the initial servo gain and the servo offset value is included.

1 is a view showing a schematic configuration of an optical pickup unit;

2 is a view showing a track jumping device of the prior art,

3 is a hardware configuration diagram for performing a track jumping method of the present invention;

4 is a detailed flowchart illustrating a preferred embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

100: disk 110: optical pickup unit

120: focusing servo unit 130: tracking servo unit

140: feed servo unit 150: regeneration unit

160: Micom 170: Memory

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

In general, the optical pickup unit enters a laser beam into the signal surface of the disk to read data recorded on the disk, and then converts the light reflected from the signal surface of the disk into an electrical signal. For accurate reading, the signal plane of the disc must be located within the depth of focus of the laser beam, while the laser beam for optical pickup must be able to accurately trace along the track of the disc. At this time, the action of controlling the signal surface of the disk to be located within the depth of focus of the laser beam is called focusing servo, and the action of controlling the laser beam for optical pickup to accurately trace along the track of the disk is called tracking servo. A system that performs focusing servo and tracking servo is called a servo system.

Therefore, after the track jump is completed, the above-described servo system is operated to read the data of the disk, where the servo system is directly related to the optical pickup unit, and thus is directly affected by the track jump. Only when the servo system is stabilized can accurate data reading be possible. That is, in the conventional case, once the disc is mounted in the optical disc system, the servo gain and servo offset value (tracking offset and focusing offset) of the servo system are detected immediately in the initial state, and then the detected initial servo gain and servo offset are detected. Servo control was performed based on the (offset) value, and even after the track jump was completed, playback was performed based on the initial servo gain and the servo offset value, which required a waiting time until the servo system was stabilized.

In view of the above, the present invention intends to perform regeneration immediately by applying another servo gain and servo offset value other than the initial servo gain and servo offset value for a predetermined time after the track jump is completed.

In addition, taking into consideration that the instability of the servo system corresponds to the track jump distance, after determining the servo gain and the servo offset value corresponding to the track jump distance through experiments or the like, when the track jump of the predetermined distance is completed, the predetermined distance By performing the servo control based on the servo gain and the servo offset value corresponding to, the playback is to be performed more quickly.

3 shows hardware for performing the track jump control method of the present invention.

In FIG. 3, the hardware for performing the track jump control method of the present invention includes a disk 100, an optical pickup unit 110, a focusing servo unit 120, a tracking servo unit 130, and a transfer servo unit 140. , A reproducing unit 150, a microcomputer 160, and a memory 170.

In FIG. 3, the optical pickup unit 110 reads data contained in the disk 110, and the focusing servo unit 120 performs focusing servo based on the focusing gain and the focusing offset value, and the tracking servo unit 130. Performs tracking servo based on the tracking gain and offset values.

In addition, the transfer servo unit 140 transfers the optical pickup unit 110 to the target track during the track jump, and the reproduction unit 150 processes the digital signal processing and MPEG signals read from the optical pickup unit 150. (Motion Picture Expert Group) Decodes, and informs the microcomputer 160 of the current playback position on the disc 100.

The memory 170 stores servo gain and servo offset values applicable to the track jump distance, and the servo gain and servo offset values corresponding to the track jump distance described above may be determined through experiments.

In addition, when the target track is determined during the track jump, the microcomputer 160 determines the track jump distance between the current playback position and the target track position provided from the playback unit 150, and then the servo gain and servo corresponding to the track jump distance. The offset value is detected, the feed servo unit 140 is controlled to dump the optical pickup unit 110 to the target track on the disc 100, and after the track jump is completed, based on the detected servo gain and the servo offset value. The focusing servo unit 120 and the tracking servo unit 130 are controlled to perform servo control for a predetermined time.

4 is a detailed flowchart illustrating a track jump method according to a preferred embodiment of the present invention, and the track jump method of FIG. 4 is performed based on FIG. 3.

In FIG. 4, in the normal playback mode S1, the focusing servo unit 120 and the tracking servo unit 130 are based on the initial servo gain and the servo offset value detected when the disc 100 is mounted in the optical disc system. The focusing servo and the tracking servo are performed on the optical pickup unit 110, and accordingly, the optical pickup unit 110 reads the data of the disk 100 and provides the data to the reproducing unit 150. The reproduction unit 150 reproduces and outputs an electrical signal provided from the optical pickup unit 110, and provides the microcomputer 160 with the current reproduction position on the disc 100.

At this time, when a jump signal is input from the outside to the microcomputer 160 (S2), the microcomputer 160 detects the target track position, receives the current playback position from the playback unit 150, and then the current playback position and the target track. The distance and the track jump distance are calculated (S3). When the track jump distance is calculated as a result of the operation, the microcomputer 160 detects the servo gain and the servo offset value set corresponding to the track jump distance from the memory 170 (S4).

Then, the microcomputer 160 controls the feed servo unit 140 so that the optical pickup unit 110 is jumped to the target track, and the feed servo unit 140 controls the optical pickup unit under the control of the microcomputer 160. 110 to jump to the target track (S5).

As a result, when the optical pickup unit 110 reaches the target track (S6), the microcomputer 160 controls the feed servo unit 140 to stop the track jump, and then detects the servo gain and servo detected in step S4. Based on the offset value, the focusing servo unit 120 and the tracking servo unit 130 are controlled to perform the focusing servo and the tracking servo.

Therefore, the focusing servo unit 120 and the tracking servo unit 130 perform the focusing servo and the tracking servo based on the servo gain and the servo offset value detected in step S4 under the control of the microcomputer 160 (S7). ). Meanwhile, although not shown in the drawing, as the focusing servo unit 120 and the tracking servo unit 130 operate, the optical pickup unit 110 reads data from the disc 100 to the playback unit 1150. Provide, and playback starts accordingly.

Thus, according to the present invention, since the playback is performed immediately after the completion of the track jump, it will be possible to perform the playback faster.

On the other hand, after the track jump is completed, the microcomputer 160 performs a focusing servo unit to perform the focusing servo and the tracking servo again based on the initial servo gain and the servo offset value when the preset time T = t1 passes (S8). The control unit 120 and the tracking servo unit 130 are controlled (S9).

As described above, the present invention enables the playback to be performed immediately after the track jump of the optical pickup unit is completed.

Claims (1)

A track jump control method of an optical disc system for jumping an optical pickup unit to a target track on a disc: A first step of performing servo control based on an initial servo gain and a servo offset value during normal reproduction; Calculating a track jump distance from a current playback position on the disc to a target track when the target track is determined in the track jump mode; Detecting a servo gain and a servo offset value set corresponding to the calculated track jump distance; A fourth step of jumping the optical pickup unit to a target track; A fifth step of, after the optical pickup unit reaches the target track, performing servo control based on the servo gain and servo offset values detected in the third step for a preset time; And in the fifth step, after the preset time has elapsed, a sixth step of performing servo control based on the initial servo gain and servo offset values.