KR0131447B1 - Optical pick-up track jump control circuit and metho of optical disk reproducing apparatus - Google Patents

Abstract

A circuit and a method of controlling a track jump of an optical pickup at an optical disk playing system are disclosed. The circuit comprises a track crossing detection circuit(24) for generating a track crossing signal, a jump driving circuit(34) for driving a driving motor(36), a pseudo track crossing signal generating circuit(26) for generating a pseudo track crossing signal, a selection switch(28) for selecting one of signal from the track crossing detection signal or the pseudo track crossing signal, a track counter(30) for counting the selected signal to generate a track count signal, and a controller(32) for controlling the jump driving circuit(34) according to the track counted signal.

Description

Track Jumping Control Circuit and Method of Optical Pickup in Optical Disc Player

1 is a block diagram of a conventional track jump control circuit.

2 is a block diagram of a track jump control circuit according to the present invention.

3 is a flowchart of a track jump control function according to the present invention.

* Explanation of symbols for main parts of the drawings

20: optical pickup 22: high frequency amplifier

24: track crossing detection circuit 26: pseudo track crossing signal generating circuit

28: selector switch 30: track counter

32: control unit 34: jump drive circuit

36: optical pickup drive motor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc reproducing apparatus, and more particularly, to an optical disc reproducing apparatus which controls a track jump by a track count method of an optical disc. The present invention relates to a track jump control circuit and a method of optical pickup for precisely moving at a maximum movable speed.

In general, optical disc playback devices such as CDP (Compact Disc Player) and LDP (Laser Disc Player) control track jumping by counting the number of tracks that are traversed while moving the optical pickup across the track on the disc when searching for the target track. The track count method is widely used.

The conventional track jump control circuit for this purpose is configured as shown in FIG. 1 to count the track crossing signal output from the track crossing detection circuit 6 when a spot of the optical pickup 2 traverses a track on the optical disc. It is used as a reference for the distance to the track. This will be described in more detail as follows. In FIG. 1, when the optical pickup 2 needs to be moved to the target track on the optical disc, the control unit 10 as a control unit controls the jump driving circuit 12 to drive the optical pickup driving motor 14. Accordingly, the optical pickup 2 moves across the track on the optical disc. In this case, the control unit 10 is a microcomputer for controlling the optical disc reproducing apparatus as a whole. At this time, the optical disk is in a state of being rotated by a motor (not shown) which is controlled and controlled by the controller 10. As described above, when the spot of the optical pickup 2 traverses the track on the optical disc, the high frequency signal generated by the optical pickup 2 is amplified by the high frequency amplifier 4 and then input to the track crossing detection circuit 6. The track crossing detection circuit 6 outputs the track crossing signal in the secondaryd state by detecting the level variation of the high frequency signal generated at the track crossing. Then, the track counter 8 counts the track crossing signal and generates and applies the track count signal to the controller 10 upon completion of counting up to a preset value. The controller 10 checks whether the target track is reached by subtracting the moving distance to the target track whenever the track count signal is input, and controls the jump drive circuit 12 when reaching the target track. Stops movement.

In order to reduce the search time of the target track, the optical pickup 2 should be moved as fast as possible. However, when the optical pickup 2 is moved at a high speed, the spot may not pass the pit row in the track of the optical disc, and the accuracy of the track crossing signal is collapsing. This phenomenon occurs in proportion to the movement speed of the optical pickup, thereby limiting the movement speed of the optical pickup during track jumping, thereby increasing the overall track jumping time.

As a technique to solve such a disadvantage, instead of using the track crossing signal, a separate peripheral device such as a scale device has been used, but it is difficult to precisely move due to the limitation of mechanical precision of the scale device. There was this.

Accordingly, it is an object of the present invention to provide an optical disc reproducing apparatus for controlling track jump by a track count method, in which an optical pickup can be accurately moved at the maximum movable speed using a pseudo track crossing signal when the optical pickup is moved at high speed. The present invention provides a track jump control circuit and method for optical pickup.

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

2 is a block configuration diagram of a track jump control circuit according to the present invention, which detects a level change of a high frequency signal generated by pickup of an optical pickup 20 and generates a track crossing signal in a quadratic state. A jump drive circuit 34 for driving the optical pickup drive motor 36 for moving the optical pickup 20 on the optical disk by a predetermined control; and at the time of track jump of the optical pickup 20; A pseudo track crossing signal generating circuit 26 which generates a clock signal of a predetermined period corresponding to the movable speed and outputs it as a pseudo track crossing signal, and the track crossing detection circuit 24 and the pseudo track crossing signal under predetermined control; A selection switch 28 for selecting an output of the generation circuit 26, a track counter 30 for counting a signal selected by the selection switch 28 and generating a track count signal upon completion of counting up to a preset value;The number of moving target tracks of the optical pickup is reduced by the track count signal, the moving speed is determined by comparing with the preset high-speed moving range, and the jump driving circuit 34 is controlled to move the optical pickup 20 to the determined movement. It consists of the control part 32 which moves at a speed.

In the configuration of FIG. 2, when the number of moving target tracks is larger than the high speed moving range, the control unit 32 moves the optical pickup 20 at high speed while the selection switch 28 causes the pseudo track crossing signal generating circuit 24 to be moved. When the number of target tracks is within the high-speed movement range, the selection switch 28 selects the output of the track crossing detection circuit 24 while moving the optical pickup 20 at low speed. To control.

3 is a flowchart of a track jump control function according to the present invention. The process of setting a high-speed moving range after determining a moving target track from a track to a target track at the current position of the optical pickup 20 in response to the setting of the jump mode. And comparing the moving target track with the high speed moving range, and moving the optical pickup 20 at high speed when the moving target track is larger than the high moving range, and the track counter 30 makes a pseudo track crossing signal. Selecting to count the output of the generation circuit 26; and moving the optical pickup 20 at a low speed when the movement target track is within the high speed moving range, and the track counter 30 is a track crossing detection circuit ( A process of selecting to count the output of 24), reducing the movement target track in response to the input of the track count signal from the track counter 30, and then completing the movement to the movement target track. By checking the completion until the process is made to proceed with the comparison process.

Hereinafter, operation examples of FIGS. 2 and 3 according to the present invention will be described in detail.

First, in Fig. 2, the optical pickup 20, the high frequency amplifier 22, the track crossing detection circuit 24, the track counter 30, the jump drive circuit 34, and the optical pickup drive motor 36 are shown. Are the same as in FIG. The control unit 32 also incorporates a program according to the flowchart of FIG. 3 into a microcomputer that generally controls the optical disc reproducing apparatus.

In order to solve the conventional problems as described above, the present invention traverses a pseudo track when the optical pickup 20 moves from a track at a current position (hereinafter referred to as a current track) to a track at a target position (hereinafter referred to as a target track). The track is counted using the signal. Accordingly, it is possible to move at the maximum movable speed without limiting the speed of the optical pickup 20, thereby reducing the overall track jump time and compensating for the missing track crossing signal.

To this end, the pseudo track crossing signal generating circuit 26 generates a clock signal of a predetermined period corresponding to the maximum movable speed at the time of the track jump of the optical pickup 20 and outputs it as a pseudo track crossing signal. At this time, the frequency of the clock signal is set based on the time taken for the optical pickup 20 to move from the innermost to outermost circumference of the optical disc at the highest movable speed. That is, assuming that the number of tracks of the optical disc is 20,000 tracks, and the time taken for the optical pickup 20 to move from the innermost to the outermost circumference of the optical disc at the maximum movable speed is 0.4 sec. The time T to traverse becomes as follows.

T = 0.4 sec / 20,000 = 20 μsec... … … (One)

Therefore, the frequency f of the clock signal is,

f = 1 / T = 1 / 20μsec = 50KHz... … … Set to (2).

In the above state, when the control unit 32 is set to the jump mode in step 301 of FIG. 3, the control unit 32 determines the movement target track from the current track of the optical pickup 20 to the target track in steps 302 to 303. After that, set the high speed range. In step 304, the moving target track and the high speed moving range are compared.

When the movement target track is larger than the high speed moving range in step 304, the jump driving circuit 34 is controlled in steps 305 and 306 to move the optical pickup 20 at high speed, and the selection switch 28 The output of the pseudo track crossing signal generating circuit 26 is selected. Accordingly, the track count 30 counts the pseudo track crossing signal and generates a track count signal every time the count is completed up to a preset value.

If the movement target track is within the high speed moving range in step 304, the jump driving circuit 34 is controlled in steps 307 and 308 to move the optical pickup 20 at low speed, and the selection switch 28 The output of the track crossing detection circuit 24 is selected. Accordingly, the track counter 30 counts the track crossing signal and generates a track count signal upon completion of counting up to a preset value.

Next, in step 309, the presence or absence of the input of the track count signal from the track counter 30 is checked. At this time, if the track count signal is not input, the operation 304 is performed again. If the track count signal is input, the movement target track is decreased in response to the input of the track count signal at step 310, and then the movement target track is performed at step 311. Check if the move is completed. At this time, when the step is not completed, the step 304 is repeatedly performed, and when the step is completed, the movement of the optical pickup 20 ends.

Here, the high speed movement means moving the optical pickup 20 at the maximum movable speed when the difference between the target track to be moved on the current track of the optical pickup 20 on the optical disc is large, that is, larger than the set high speed movement range. . The low-speed movement means moving the optical pickup 20 at a low speed when the optical pickup 20 approaches the target track during the high-speed movement, that is, within the high-speed movement range.

Therefore, when the moving target track is larger than the high-speed moving range, the moving target track is reduced by the track count signal according to the count of the pseudo track crossing signal while the optical pickup 20 is moved at high speed, and the optical pickup 20 during the high-speed moving is the target. When the optical pickup 20 is moved at a low speed in proximity to the track and the optical pickup 20 is moved at a low speed, it is controlled to jump to the target track by decreasing the moving target track by the track count signal according to the count of the track crossing signal.

As described above, according to the present invention, the track crossing signal, which is dropped at the time of track counting according to the high speed of optical pickup, can be compensated by the pseudo track crossing signal. Being able to jump at possible speeds has the advantage of reducing the overall search time.

Claims (3)

A track crossing detecting means for detecting a level change of a high frequency signal generated by pickup of an optical pickup and generating a track crossing signal in a binarized state; and an optical pickup driving motor for moving the optical pickup on an optical disc by predetermined control. An optical disc reproducing apparatus having a driving unit for driving jump, comprising: pseudo track crossing signal generating means for generating a clock signal of a predetermined period corresponding to the maximum movable speed during track jump of the optical pickup and outputting it as a pseudo track crossing signal; Selecting means for selecting outputs of the track crossing detection means and the pseudo track crossing signal generating means by a predetermined control; a track for counting a signal selected by the selection means and generating a track count signal upon completion of counting up to a preset value; The counter means and the number of moving target tracks of the optical pickup are reduced by the track count signal. A track jump control circuit for optical pickup, comprising: control means for determining the moving speed in comparison with the predetermined high speed moving range while controlling the jump driving means to move the optical pickup at the determined moving speed. . 2. The control apparatus according to claim 1, wherein the control means selects an output of the pseudo track traverse signal generating means while moving the optical pickup at a high speed when the moving target track number is larger than the high speed moving range. And the selection means controls the selection means to select an output of the track traverse detecting means while moving the optical pickup at a low speed when a target track number is within the high-speed movement range. Generating an optical pickup, a track crossing detecting means for generating a track crossing signal, a jump driving means for driving an optical pickup driving motor, and a clock signal having a predetermined period corresponding to the maximum movable speed during track jumping of the optical pickup; A pseudo track crossing signal generating means for outputting as a pseudo track crossing signal, selection means for selecting outputs of said track crossing detection means and said pseudo track crossing signal generating means by predetermined control, and counting the signal selected by said selecting means A track jump control method for an optical pickup in an optical disc reproducing apparatus having a track counter means for generating a track count signal upon completion of counting up to a preset value, the current position of the optical pickup in response to setting of a jump mode. Determining a moving target track from the track to the target track and setting a high-speed moving range; Comparing the rack with the high-speed moving range, and moving the optical pickup at high speed when the moving target track is larger than the high-speed moving range, and selecting a track counter means to count the output of the pseudo-track transverse signal generating means. And moving the optical pickup at a low speed when the moving target track is within the high speed moving range, and causing the track counter means to select the output of the track crossing detection means to count the track from the track counter means. And a process of proceeding to the comparison process until the movement target track is completed by reducing the movement target track in response to the input of a count signal, and checking the completion of movement to the movement target track. .