JPS62188030A - Movable part controller for optical pickup - Google Patents

Abstract

PURPOSE:To place an optical system movable system in normal operation immediately even after pickup fast conversion by supplying a signal proportional to the acceleration of an optical pickup to an actuator and canceling inertial force. CONSTITUTION:A movable contact is switched 29 to a terminal B by a control circuit 34 when access is attained, and a motor 32 is driven 33 to move the optical pickup 21 at a high speed. Its acceleration is detected 31 and the signal proportional to the acceleration is adjusted and amplified 30 to drive 38 the actuator 23, suppressing inertial force generated at the optical system movable part 24 owing to the acceleration neither excessively nor deficiently. For example, the inertial of the objective 11 is cancelled by an electromagnetic couple 15 and a magnetic piece couple 16 to eliminate unnecessary displacement. In this constitution, the pickup does not fluctuates at its stop and enters normal operation right after movement.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an optical information recording device or an information reproducing device, and in particular, the present invention relates to an optical information recording device or an information reproducing device, and in particular, when an optical pickup is moved, optical system movable parts such as an objective lens etc. The present invention relates to a movable part control device for an optical pickup.

(Prior art) Conventionally, a disk is used as an information recording medium, a spiral or concentric information track is formed on the disk surface, and a light beam such as a laser beam is irradiated onto the disk to optically reproduce information signals. There is a device that does this. For example, in the case of compact discs and their playback devices, as is well known, a pit array corresponding to digitized data is formed on a 12ffi diameter disk, and the playback device is equipped with an optical pickup equipped with a semiconductor laser, a photoelectric conversion element, etc. The data recorded on the disk is read by moving the disk from the inner circumferential side to the outer circumferential side of the disk in an IJ near-tracking manner, and simultaneously rotating the disk in a linear velocity-direction manner. Furthermore, in recent years, in addition to a playback function, devices that can optically record information on a disk, or devices that can erase recorded information and re-record it, have been actively researched.

In these optical disk recording and reproducing devices.

In order to record a large amount of information at high density and to reproduce the recorded information, the light beam irradiated onto the disk surface is narrowed down to about the wavelength of the light. Since it is necessary to focus the original beam on the track correctly, focusing and tracking controls are performed by adjusting the focusing point of the light beam in the vertical and radial directions relative to the disk surface. In general, such a light beam control method involves detecting focus errors and tracking errors from reflected light or transmitted light of the light beam irradiated onto the disk surface, and configuring an optical system based on the output signals. Many systems have been adopted in which a movable part, such as a reflective bell or an objective lens, is driven by an actuator to correct the above-mentioned errors.

For example, in an optical pickup α in which the objective lens αυ is the movable part as shown in FIG.
4a) and (14b) so as to be movable in the horizontal direction in the figure, and the tracking actuator that drives the objective lens al).

Electromagnet (15Jl), (15b) and objective lens 0υ
It is composed of magnet pieces (16a) and (16b) attached to.

This actuator is operated by an electromagnet (15a) according to the tracking error signal of the servo circuit (not shown).
, (15b), a magnetic field is generated, and this action applies power to the objective lens Ql). Although FIG. 4 shows only the control of the movement of the objective lens for tracking, the configuration for focusing can be basically the same and is well known in the art.

On the other hand, since the optical disk recording/reproducing apparatus uses a disk as a recording medium, it is characterized by an extremely short access time for searching for desired information compared to an apparatus using a tape as a medium. In addition, because the recording capacity of the optical disc is enormous, the recording and reproducing device is not only used for recording and reproducing images and music information, but also for data storage devices such as computers, or devices where information retrieval ability is particularly important. It is being promoted to apply it to Along with that,
There is a demand for even faster data access.

By the way, in the above-mentioned optical disk recording/reproducing device, the operation of searching for desired information, that is, the access operation, is performed by moving the optical pickup a predetermined distance from the current position in the tracking direction in comparison with the position information of the information intended for the optical pickup. It moves at high speed. At this time, the above-mentioned tracking servo is cut off, and the optical system movable part (objective lens αυ in FIG. 4) becomes able to move freely within its movable range. Therefore, when the optical pickup moves, an inertial force acts on the optical system movable part due to the acceleration ζ generated by the movement, and the inertial force causes the optical system movable part to be displaced unnecessarily.

Therefore, immediately after the optical pickup is moved at high speed, such as during an access operation, there is a residual amount of displacement caused in the optical system movable part due to the above-mentioned inertial force. It takes time to get it back. This poses a major problem in reducing the data access time of the optical disk recording/reproducing device.

(Problems to be Solved by the Invention) As described above, when the optical pickup is moved at high speed, the movable parts of the optical system for tracking or tracking become unnecessary due to inertia caused by the movement of the entire optical pickup. To be displaced.

Normal operations such as servo pull-in cannot be performed immediately after the optical pins, quads, and pins move, resulting in a delay in data access time.

The present invention has been made to solve the above-mentioned problems, and is an optical pickup movable part control that prevents unnecessary displacement of the optical system movable part when the optical pickup moves at high speed and contributes to faster data access. The purpose is to provide equipment.

[Structure of the invention]

(Means for Solving the Problems) A movable part control device for an optical pickup according to the present invention includes an optical system movable part that causes a displacement in the condensing position of a light beam, and an actuator that moves this optical system movable part. When an optical pickup equipped with an optical pickup moves at high speed, a control system generates a signal proportional to the acceleration of the optical pickup and supplies that signal to the actuator to compensate for the inertial force acting on the optical system's movable parts. It is equipped with the means.

(Function) In the movable part control device for an optical pickup having the above means, by supplying the actuator with an impulse proportional to the acceleration of the optical pickup.

The actuator applies a force corresponding to the above-mentioned inertial force to the optical system movable part in a direction to cancel the inertial force.

It acts to prevent unnecessary displacement of the optical system movable part.

As a result, the optical system movable section can immediately operate normally even immediately after the optical pickup moves at high speed.

(Example) An example of the present invention will be described below in detail with reference to the drawings. Although FIGS. 1 to 7jg3 each show different embodiments, the same parts are given the same reference numerals to avoid duplication of explanation.

FIG. 1 is a diagram showing a transmission path of control signals and the like in a movable part control device of an optical pickup, according to an embodiment of the present invention. Normally, the actuator is controlled when recording or reproducing information.

The error component of the focusing position is detected by the reflected light (or transmitted light) of the light beam irradiated from the optical pickup Qυ onto the recording medium (2), and the actuator (to) is driven based on the error signal to activate the optical system. It is configured in a servo loop that moves the movable part 124) to an appropriate state and corrects the focusing position. In the example of the tracking servo shown in Fig. 1, the tracking error signal detected by the tracking error signal detection section is sent to the actuator driver (
c), and drive the actuator (to) according to the torment and king errors. Here, a changeover switch (2) is inserted in the input wire number of the actuator driver (c), and the movable contact of this changeover switch is connected to the A terminal in the figure during normal recording and playback operation, and is connected to the A terminal in the figure for one phase. The output of the compensation circuit (5) is led to the actuator driver (to).

On the other hand, the B terminal in the figure of the changeover switch ■ above has the following.

An acceleration detector 0υ is connected via an amplification factor adjustment circuit (7). This acceleration detector Gυ is activated when the operation mode shifts from recording/reproducing operation to access operation.

It detects the acceleration due to high-speed movement of the optical pickup Q1), and outputs a signal proportional to the acceleration to the amplification factor adjustment circuit (to). Here, the access operation is performed by applying a predetermined voltage from the feed motor drive circuit (to) to the feed motor that applies a moving force to the optical pickup Qυ, which is controlled by the feed control circuit (b). .

This feed control circuit (F) is started by a control signal from the main control section that controls the system according to key input (1) not shown, and when the feed motor 02 is driven, the movable contact of the changeover switch (C) is activated at the same time. Switch to B terminal.

That is, in the control system having the above configuration.

When an access operation is requested, first a switching operation is performed by the feed control circuit (incorporated) to connect the movable contact of the changeover switch (2) to the B terminal, and the tracking servo loop is broken. At the same time, a drive signal is supplied from the feed control circuit (b) to the feed motor Oda via the feed tanabata drive circuit (to), and the optical pickup (21) starts moving at high speed. Then, the speed change, that is, the acceleration of the optical pickup Cυ is detected by the acceleration detector t31), and a detection signal proportional to the acceleration is supplied to the actuator driver (to) via the amplification factor adjustment circuit (2). here,
The signal output from the amplification factor adjustment circuit (to) is sent to the actuator using the actuator driver (to)! ,!
hi is applied in the direction of suppressing the inertial force generated in the optical system movable part @ by the above acceleration, and it is amplified by the amplification factor set so that the suppressing force works just the right amount by the amplification factor adjustment circuit (to). It is something that In other words, the inertial force generated in the moving part of the optical system is the optical pickup Qυ
Since it is proportional to the acceleration of , the same force can be generated by the actuator (c). If the actuator (c) controlled in this way is, for example, the one shown in FIG.
) and magnet pieces (16a) and (16b) to generate enough force to cancel the inertial force of the objective lens aυ, and to prevent unnecessary displacement of the objective lens Uυ during high-speed movement.
help

Therefore, according to the movable part control bag section of the optical pickup of this embodiment, the optical pickup (21
), especially when the optical pickup Q
When υ is stopped, the moving parts of the optical system are damaged due to inertia.
The moving parts of the optical system can be prevented from wandering around, and the movable parts of the optical system can resume normal operation immediately after being moved. In other words, data access time is reduced. In addition, in this embodiment, an actuator (c) and an actuator driver (c) used for controlling the light focusing position during recording and reproducing operations are used.
Since it is also used to control the above-mentioned movable part during access operation, there is no need to provide a special drive member to suppress the inertial force of the optical system movable part, and the optical system of the optical pickup Cυ can be changed. Since this is not necessary, it is possible to provide a simple and practical moving part control device for an optical pickup.

Note that the acceleration detector 61) used in the above embodiment is as follows:
Any device that can respond quickly to the movement of the optical pickup Qυ and measure it with some degree of accuracy may be used.1 For example, see "Sensor Story" published by Nikkan Kogyo Shimbun (December 20, 1981) by Hiroshi Yamazaki. A gutter-type detector described in "Chapter 7 @ 7.8 Acceleration Sensor" (page 87) by the author, can be used.

FIG. 2 shows another embodiment of the invention. here,
a speed detector (41) that detects the moving speed of the one-dimensional pickup (21) to generate a signal proportional to the acceleration of the optical pickup Qυ during an access operation;

A differentiation circuit (44) is provided to differentiate the detection output.

That is, from the speed detector (41) to the optical pickup Cυ
A signal proportional to the moving speed of the motor is output, and by differentiating the signal using a differentiating circuit (four-way circuit), a signal proportional to the rate of change in speed, that is, the acceleration, is generated.

By supplying this to the actuator driver (c) via the amplification factor adjustment circuit (43) and the changeover switch (to), it is possible to cancel the inertial force generated in the optical system movable part Qa during the access operation. It is possible to obtain the same effect as above.When applying this embodiment, if a method that already includes a speed detector is used for the movement control method of the optical pickup, it is not necessary to provide a new detector. Figure 3 shows still another embodiment of the present invention.

In this embodiment, a so-called linear motor 6υ is used as the motor for sending the optical pickup υ, and a force proportional to the signal sent from the feed control circuit (b) through the feed motor drive circuit 6 is applied to the optical pickup C. The old one works properly. Therefore, an acceleration proportional to the control signal from the feed control circuit (2) is generated in the optical pickup Qυ. Therefore, during access operation, the control signal output from the feed control circuit (b) is amplified by the amplification factor adjustment circuit board.
After adjusting, supply to the actuator driver (to) via the changeover switch (c), and the optical system moving part (
It is possible to cancel the inertial force that occurs in

Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above and illustrated; for example, depending on the configuration of the optical system of an optical pickup,
(In some cases, it may be a reflecting mirror) may be controlled by a focusing actuator, and various other modifications may be made without departing from the gist of the present invention.

〔Effect of the invention〕

As described above, according to the present invention, unnecessary displacement of the optical system movable part that occurs when the optical pickup moves at high speed is prevented,
A movable part control device for an optical pickup that contributes to faster data access can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG.
3 is a block diagram showing another embodiment of the present invention, FIG. 3 is a block diagram showing still another embodiment of the present invention, and FIG.
The figure is a cross-sectional view schematically showing the head portion of the optical pickup. 21... Optical pickup, 22... Recording medium. Trap...actuator, 24...optical system movable part. Wings: Actuator driver. 4.--Switch switch, 30, 43.52...
Amplification factor adjustment circuit. 31... Acceleration detector, 32... Feed motor, 33
. . . feed drive circuit, 34 . . . feed control circuit. 41... Speed detector, 42... Differential circuit. 51...Linear motor. Falcon 4

Claims (4)

[Claims] (1) An optical pickup that optically writes or reads a recorded information string by irradiating a light beam onto a recording medium, a moving means for moving the optical pickup, and a means for moving the optical pickup, which is provided in the optical pickup to an optical system movable part that causes a displacement in the light focusing position; an actuator that moves the optical system movable part; and a drive signal proportional to the acceleration of the optical pickup when the optical pickup is moved to the actuator, and 1. A movable part control device for an optical pickup, comprising a control means for compensating for inertial force related to a system movable part. (2) The movable part control device for an optical pickup according to claim 1, wherein the control means includes an acceleration detector that detects acceleration of the optical pickup. (3) The optical pickup according to claim 1, wherein the control means includes a speed detector that detects the moving speed of the optical pickup and a differentiation circuit that differentiates the detection output thereof. Moving part control device. (4) The moving means includes a linear motor that moves the optical pickup and a circuit that supplies a drive control signal to the linear motor, and the control means supplies the actuator with a drive signal proportional to the acceleration of the optical pickup. 2. The movable part control device for an optical pickup according to claim 1, wherein the device supplies a signal proportional to the control signal.