JP2899505B2 - Track jumping equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a track jump apparatus in an optical disk apparatus capable of performing a so-called track jump process in which a track jumps in a radial direction.

[0002]

2. Description of the Related Art In recent years, a reproduction-only optical disk device for reproducing a compact disk in which an audio signal is recorded on an optical disk, an optical video disk in which an audio signal or a moving image signal is recorded on an optical disk, and the like, have become widespread. Recording / reproducing optical disk devices such as optical disks and magneto-optical disks have also been developed. In such an optical disk device, a feature of a disk-shaped recording medium, that is, a high-speed jump access utilizing the fact that data is recorded on the same plane is an important functional feature.

As a conventional track jump apparatus, there is one disclosed in, for example, Japanese Patent Application Laid-Open No. 5-28672. FIG. 4 is a block diagram of a conventional track jump device. In this conventional example, a tracking error detection circuit 42 that outputs a tracking error signal indicating a tracking error amount of an optical pickup 41, a phase compensation circuit 43 that performs phase compensation on the tracking error signal, and a jump for performing a track jump A driving pulse generator 44;
A tracking error level detection circuit 45 for measuring the level of the tracking error signal; switching means 46 for switching a signal to be output to a driving circuit 47;
6, a control unit 49 for controlling the jump drive pulse generator 44 and the tracking error level detection circuit 45, and a tracking actuator 48. When performing a track jump, the jump drive pulse generator 44
Thus, a kick pulse and a brake pulse for crossing the track are generated, and by switching the switching means 46, the pulse is applied to the tracking actuator 48 to realize a track jump. Further, in this conventional example, the tracking error level detection circuit 45 detects the level of the tracking error signal, and adds a jump correction pulse based on this level to the kick pulse, thereby stabilizing the jump of one track. ing.

[0004]

With such a track jump apparatus, it is possible to jump accurately when the number of tracks to be jumped is small, but it is necessary to increase the number of tracks or to jump in a short cycle. Jumps could not be performed correctly when processing such as repeating was performed. This is because the movement of the tracking actuator due to the kick pulse exceeds the movable range. In particular, when two-stage servo combining a tracking actuator and a coarse motor is performed in order to secure the movement amount of the light spot in the radial direction, the movement by the coarse motor is very slow. However, there has been a problem that the track jump fails.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to realize a track jump device capable of more stably jumping a large number of tracks.

[0006]

A track jump device according to the present invention comprises: a level detecting means for detecting an average tracking error amount, in other words, a delay amount of a coarse motor with respect to the movement of a tracking actuator; Control means for determining the crest value and width of the forcible feed pulse to be applied to the coarse motor based on the detected tracking error amount, and forcible feed pulse generating means for generating the forcible feed pulse in accordance with an instruction from the control means. Features.

[0007]

According to the present invention, by providing the above-mentioned means, it is possible to optimize the peak value and the width of the forcible feed pulse for driving the coarse movement motor, and it is possible to perform a large number of track jumps more stably. It becomes possible.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a track jump device according to one embodiment of the present invention.

In FIG. 1, reference numeral 11 denotes an optical disk having concentric or spiral tracks on which information is recorded;
Reference numeral 12 denotes an optical pickup having a tracking actuator for moving a light spot irradiated on the optical disk 11 in a radial direction; 13, a tracking error detection circuit that generates and outputs a tracking error signal based on a signal output from the optical pickup 12; Is a tracking phase compensation circuit that receives a tracking error signal, performs low-frequency compensation and high-frequency compensation, and outputs the result. 15 is a kick that generates a kick pulse or a brake pulse applied to a tracking actuator to perform a track jump. A pulse generation circuit 16 is a tracking drive switching circuit that switches a signal applied to the tracking actuator to either the output of the tracking phase compensation circuit 14 or the output of the kick pulse generation circuit 15.
7 is a traverse error detection circuit that extracts and outputs a low-frequency component of the tracking error signal, 18 is a traverse phase compensation circuit that performs low-frequency compensation and dead band processing on the signal output by the traverse error detection circuit 17 and outputs the signal. Is a forced feed pulse generating circuit for generating a forced feed pulse for driving the coarse motor 112 in an open loop, and 110 is a traverse phase compensating circuit 18 or a forced feed pulse generating circuit 19 for applying a signal applied to the coarse motor 112. A traverse drive switching circuit for switching to any one of the outputs, 111 is a level detection circuit for measuring and outputting an average value of the tracking error signal, 112 is a coarse motor, and the rotational motion of the coarse motor 112 is a lead screw. Is converted into a parallel motion by moving the optical pickup 12 in the radial direction. It has a mechanism. A control circuit 113 controls the tracking drive switching circuit 16, the traverse drive switching circuit 110, and the level detection circuit 111.

First, when a normal two-stage servo is operating, the tracking drive switching circuit 16 and the traverse drive switching circuit 110 output signals output from the tracking phase compensation circuit 14 and the traverse phase compensation circuit 18, respectively. Can be switched. as a result,
The tracking actuator is driven by a signal obtained by performing phase compensation on a tracking error signal, and the coarse movement motor 112 is driven by a signal obtained by performing phase compensation and dead band processing on a signal output from the traverse error detection circuit 17.

When performing a track jump, the control means 1
Reference numeral 13 indicates that the tracking drive switching circuit 16 is tilted toward the kick pulse generation circuit 15 to perform a track jump of one track. The signal applied to the tracking actuator and the tracking error signal in this case are shown in FIG.
Shown in 21 is a kick pulse and 22 is a brake pulse. When a plurality of track jumps are performed, the same operation is repeated. In this case, however, it can be seen that the tracking error signal after the application of the brake pulse deviates from the center point as shown in FIG. This is because the movement of the optical pickup 12 by the coarse movement motor 112 cannot keep up with the movement of the tracking actuator by the kick pulse. Therefore, the control means 113 switches the tracking drive switching circuit 16 to the tracking phase compensation circuit 14.
Level detection circuit 1
11 to calculate the average of the tracking error signal during the period (32 in FIG. 3) in which the output of the tracking phase compensation circuit 14 is applied to the tracking actuator.
This value corresponds to 31 in FIG. 3, and from this value, the control means 113 can know how much the coarse movement motor 112 is delayed. The control means 113 controls the level detection circuit 11
It monitors whether or not the average tracking error amount output by 1 exceeds the first threshold value, and if it exceeds, sends an instruction to the forced-feed pulse generation circuit 19 to generate a forced-feed pulse. For the peak value and the width of the forced feed pulse, an average value is stored in advance in the control means 113,
This is set in the forced feed pulse generation circuit 19. At the same time, the control means 113 controls the traverse drive switching circuit 11
0 is forced to the side of the forced feed pulse generation circuit 19, and the coarse motor 112 is driven by the forced feed pulse. The coarse movement motor 112 is driven by the forcible feed pulse to move the optical pickup 12 in parallel. If the magnitude of the forcible feed pulse is optimal, the tracking error amount output by the level detection circuit 111 after the optical pickup 12 moves is 0. However, if the magnitude of the forcible feed pulse is large or small, tracking is performed. Errors remain. Control means 1
In step 13, the remaining tracking error is input, and if this value has the same polarity as before the application of the forced-feed pulse, it is considered that the optical pickup 12 is not moving enough and the peak value of the forced-feed pulse is increased. If the polarity is opposite, the amount of movement is considered to be too large, and the peak value is reduced or the width is reduced. By adjusting the width of the forced-feed pulse in this way, it is possible to generate an optimal forced-feed pulse.

In the first embodiment, the delay of the coarse motor is detected by monitoring the tracking error signal. For example, a position sensor for outputting the position of the objective lens in the optical pickup is provided. May be detected.

[0013]

As described above, according to the present invention,
Since the peak value and width of the forced feed pulse applied to the coarse motor can be optimized, the track jump can be performed stably even when performing a large number of track jumps or repeating one track jump. It is possible to do.

In particular, since one track jump can be operated very accurately, the fact that it can be operated stably a plurality of times means that the desired number of jumps can be performed accurately. This means that the effect is practically large.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a track jump device according to an embodiment of the present invention.

FIG. 2 is a waveform chart showing an operation at the time of a track jump of the embodiment.

FIG. 3 is a waveform chart showing an operation of the embodiment when a track jump is repeated.

FIG. 4 is a block diagram showing a configuration of a conventional track jump apparatus.

[Explanation of symbols]

 13 tracking error detection circuit 17 traverse error detection circuit 110 traverse drive switching circuit 111 level detection circuit 113 control circuit

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 21/08 G11B 7/085

Claims (1)

(57) [Claims] 1. An optical pickup having a tracking actuator for moving a position of a light spot irradiated on an optical disk in a substantially radial direction, and a tracking indicating a positional displacement amount in a radial direction between the light spot and a track on the optical disk. Tracking error detecting means for generating an error signal; traverse moving means for moving the optical pickup in a substantially radial direction; tracking control means for driving a tracking actuator according to the tracking error signal; and a track adjacent to the light spot. A kick pulse generating means for generating a kick pulse signal for moving the tracking drive means; a tracking drive switching means for applying one output of the tracking control means and the kick pulse generating means to the tracking actuator; A traverse error detecting unit that extracts and outputs a low-frequency component of the tracking error signal; a traverse control unit that drives a traverse moving unit according to a signal output by the traverse error detecting unit; a tracking actuator and a traverse moving unit A displacement amount detecting means for detecting a displacement amount of the position of the center point of the fork; a forced feed pulse generating means for generating a forced feed pulse to be applied to the traverse moving means in an open loop; a detection result of the displacement amount detecting means Control means for controlling the height and width of the forced-feed pulse generated by the forced-feed pulse generation means, based on the output of one of the traverse control means and the forced-feed pulse generation means to the traverse control means Traverse drive switching means for applying Click jump apparatus.