JPS63127437A - Track jump system for optical disk device - Google Patents

Abstract

PURPOSE:To quickly and stably perform multitrack jump to increase the access speed by controlling the moving speed of a light beam at the time of track jump. CONSTITUTION:When jump is started, a control circuit 10 cuts off a servo circuit 9 and operates a jump voltage applying circuit 8 to accelerate an actuator 2. When the acceleration end signal is sent from the circuit 10 to the circuit 8 after a certain time, the actuator 2 is moved at a certain speed. When the counted value of a counting circuit 11 reaches a prescribed deceleration start value corresponding to the number of jump tracks in this state, the circuit 10 sends a deceleration start signal to the circuit 8 and sends the deceleration end signal there after a certain time, and simultaneously, a tracking servo leading-in start signal is sent from the circuit 10 to a servo circuit 9. As the result track jump is quickly and stably performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention improves the access speed in multi-track jumping of an optical disk device by controlling the moving speed of a light beam during track jumping. The aim is to

[Industrial application field]

The present invention provides a multi-track jump for an optical disc device.
In particular, it relates to high-speed and stable multi-jumps using only optical head actuators.

Optical disk devices serve as external storage devices for computers.
Although it has the advantage of being small and has a large capacity, it has the disadvantage that the access time is slower than that of a magnetic disk device, and improving the access time is important for expanding the range of applications for optical disk devices.

[Conventional technology]

FIG. 4 shows a block diagram of a jump control circuit in a conventional optical disc device. In the figure, 1 is an optical disc;
2 is a minute tracking actuator built into the optical head; 3 is a beam splinter that transmits the light emitted from the laser diode 5 and separates the light reflected from the optical disk 1;

4 is a collimator lens that converts the light emitted from the laser diode 5 into parallel light, and 6 is a photodetector, which is of a split type. 7 is a differential amplifier that outputs a track error signal.

8 is a jump voltage application circuit for jump driving the actuator 2, 9 is a servo circuit for servo driving the actuator 2, 10 is a control circuit for controlling the jump voltage application circuit 8 and the servo circuit 9, and 11 is the aforementioned circuit. This is a counting circuit that counts the number of track crossings from a track error signal.

FIG. 5 shows a waveform diagram for explaining the multi-jump method of a conventional optical disk device.
is the track error signal waveform of the differential amplifier, and one cycle represents one trunk, and this example shows the case of six track jumps. (d) shows the control signal waveform of the servo circuit 9, and FIG. 5 will be explained below with reference to FIG. 4.

In the conventional multi-jump method of an optical disk device, the control circuit 10 turns off the control signal of the servo circuit 9 at the start of a jump, and at the same time the jump voltage application circuit 8 turns off the control signal of the fifth
When the accelerating voltage 12 shown in the figure (al) is output and the laser beam has moved halfway to the target track, the decelerating voltage 13
When the target track is reached, the voltage application is stopped and the control signal of the servo circuit 9 is turned on.

[Problem that the invention seeks to solve]

In the multi-jump method of conventional optical disk devices, acceleration and deceleration are switched when the count number of the counting circuit 11 becomes half of the target number of tracks. Due to a delay in the reaction of It has the disadvantage of being unstable.

(2) If the count circuit 11 incorrectly counts the number of tracks due to noise or the like, the acceleration and deceleration times will be significantly different, and there is a drawback that jumps will not be stable due to excessive acceleration or deceleration.

■ ■ To solve the problem of delay, there is a method of lowering the voltage of the acceleration/deceleration pulse to reduce the proportion of the delay time in the overall jump time, but with this method the jump time is long (or The disadvantage is that the eccentricity of the disc has a greater effect on the jump, making the jump less stable.

The present invention was created in view of the above-mentioned drawbacks of the conventional art, and aims to provide a trunk jump method that can stabilize jumps and speed up access time.

[Means for solving problems]

As shown in FIG. 1, in the trunk jump method of the optical disk device of the present invention, at the start of a jump, the control circuit 10 turns off the servo circuit 9, activates the jump voltage application circuit 8 to accelerate the actuator 2, and starts the count circuit 11. The control circuit 10 changes the output of the jump voltage application circuit 8 to a deceleration mode according to the timing and control waveform determined in advance by the output, and when the deceleration is completed, the jump voltage application circuit 8 is turned off and the servo circuit 9 is activated.

[Effect]

The control circuit 10 of the present invention turns off the servo circuit 9, activates the jump voltage application circuit 8, and accelerates the actuator 2 at the start of a jump. Thereafter, as shown in FIG. 3, after a certain period of time T has elapsed, the control circuit 10 sends a signal to end the acceleration to the jump voltage application circuit 8, and the actuator 2 is in a state where it continues to move at a constant speed.

In this state, when the count value in the count circuit 11 reaches a predetermined deceleration start value corresponding to the number of jump tracks, the control circuit IO sends a deceleration start signal to the jump voltage application circuit 8.

Thereafter, when a certain time T'' has elapsed, the control circuit 10 sends a signal to the jump voltage application circuit 8 to end the deceleration, and at the same time, the control circuit 10 sends a signal to the servo circuit 9 to start track servo pull-in.

This method allows for high-speed and stable track jumping.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

Note that, in order to make the explanation of the configuration and operation easier to understand, the same parts are given the same reference numerals throughout all the figures, and repeated explanation thereof will be omitted.

FIG. 1 shows a block diagram of a track jump method of an optical disc device according to the present invention. In the figure, 14 is the control circuit 1
0 has a built-in microcomputer (hereinafter referred to as microcomputer); 15 is a memory consisting of a ROM connected to the microcomputer 14; 16 is a timer connected to the microcomputer 14 and instructs the application time of the jump voltage application circuit 8; and 17 is a A counter built into the count circuit 11 that counts the timing of the start of deceleration is shown.

FIG. 2 is a flowchart showing the operating procedure of the microcomputer 14 in FIG.

FIG. 3 shows a waveform diagram for explaining the multi-jump method of the optical disk device of the present invention, where 2nd 1 (a) is the acceleration/deceleration pulse waveform, (kl) is the moving speed of the actuator,
(C1 is the track error signal waveform of the differential amplifier, and represents one track in one cycle; this example shows the case of 6 track jumps. (d) is the control signal waveform of the servo circuit 9, as shown below. 1 and 2 will be explained with reference to FIG. 3.

In FIG. 1, the processing procedure shown in FIG. 2 starts from the time when a command indicating the number of tracks to jump to and the jump direction is input to the microcomputer 14 from an external command system (not shown).

In step 21, the microcomputer 14 reads the ROM from a table created in advance corresponding to the number of jump tracks received.
15, the count number n is set in the counter 17, and the accelerating voltage application time T and deceleration voltage application time T'' shown in FIG. 3(a) are set in the timer 16.

In step 22, the control circuit 10 is operated to
As shown in (b) and (d), the servo circuit 9 is turned off, an accelerating voltage is applied to the jump voltage application circuit 8, and the timer 16 and counter 17 are activated.

When the timer 16 reaches the set time T in step 23, the acceleration voltage for the jump voltage application circuit 8 is turned off.
The FF flipping speed is terminated, and thereafter the movement is moved to a constant speed as shown in FIG. 3(b).

Next, in step 24, the count number of the counter 17 is read. In step 25, it is determined whether the count number of the counter 17 has reached n, and if it has not reached n, step 24
When the jump voltage is reached, a deceleration voltage is applied to the jump voltage application circuit 8 in step 26 to start deceleration and at the same time start the timer 16.

When the deceleration time T' set in the timer 16 is reached in step 27, the deceleration voltage to the jump voltage application circuit 8 is turned off as shown in FIG. 3(a) fb) fd).
The servo circuit 9 is turned on to end the deceleration and the servo circuit 9 is turned on to end this processing procedure.

In addition, in step 21, the microcomputer 14 uses the ROM 15 to calculate the acceleration voltage application time T and the deceleration voltage application time T° shown in FIG. It is also effective to set the pulse widths H and H' instead of the time TST.

In this method, the acceleration/deceleration times T, T' and the peak values H, H' of the acceleration/deceleration pulses are predetermined values corresponding to the number of jump tracks, so acceleration can be achieved in any case. The total energy of the jump and the total energy of the deceleration are constant values, and even if there is an erroneous count due to noise etc., the relative speed of the actuator 2 to the track at the end of the jump can be kept within a range that allows the track servo to be pulled in. , you can achieve stable jumps. Furthermore, when the number of jump tracks is large, high-speed jumps can be realized by increasing the acceleration/deceleration times T, T' or by increasing the peak values H, H' of the acceleration/deceleration pulses.

〔Effect of the invention〕

As described above in detail, according to the track jump method of the optical disc device of the present invention, stable and high-speed multi-track jump can be realized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram for explaining the track jump method of the optical disk device of the present invention, FIG. 2 is a flowchart showing the operation procedure of the track jump method of the present invention, and FIG. 3 is the output signal of the circuit of FIG. 1. Waveform diagram FIG. 4 is a block diagram of a jump control circuit in a conventional optical disk device, and FIG. 5 is an output signal waveform diagram of the circuit shown in FIG. In the figure, 2 is an actuator, 8 is a jump voltage application circuit, 9 is a servo circuit, 10 is a control circuit, and 11 is a count circuit. UnNe my Ju1ty+7°0-z7Gffi Figure 1 Ki start octopus 470-+ Yard Figure 2 Figure 3 Ministry 1 total-shi'shi shift, port zumu pD one pro,, 7δσ
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Claims (4)

[Claims] (1) An actuator that controls the position of the light beam, a jump voltage application circuit that applies acceleration/deceleration pulses for track jumping to the actuator, and a jump voltage application circuit that detects when the light beam crosses a track and detects the number of times the light beam crosses the track. What is claimed is: 1. A track jump method for an optical disk device, characterized in that the moving speed of a light beam at the time of a track jump is controlled according to the number of jump tracks. (2) The moving speed of the light beam is controlled according to the number of jump tracks by changing the width or height of the acceleration pulse applied to the actuator. Track jump method for optical disc devices. (3) Change the width or height of the deceleration pulse in accordance with the change in the width or height of the acceleration pulse, and adjust the moving speed of the light beam on the target track to a range where the track servo pull-in at the end of the jump is stable. A track jump method for an optical disc device according to claim (1), characterized in that the track jump method is controlled within the range of 100 to 100%. (4) A track jump method for an optical disc device according to claim (1), characterized in that the timing for outputting the deceleration pulse is set before the target track by using the output of the count circuit.