JP2565967B2 - Optical information recording / reproducing device - Google Patents

Description

The present invention relates to an optical information recording / reproducing device (hereinafter referred to as an optical disc device), and more specifically, a device for optically recording / reproducing information on / from an optical disc. The movement control of the optical head.

<Prior Art> Conventionally, an optical disk device has the configuration shown in FIG.
Information tracks (not shown) are arranged concentrically or spirally on a disc 1 which is an information carrier. The disk 1 is rotated by the motor 2, and the light flux from the light emitting element provided in the optical head 3 is condensed by the objective lens to irradiate the track on the disk surface 1. Information is reproduced by the reflected light of the irradiated light beam 4. Second, a schematic diagram showing a schematic structure of the optical head 3 is shown.
Shown in the figure. The objective lens 5 is movable up and down and left and right.

By moving the objective lens 5 in the vertical direction, control (focusing servo) for maintaining the focus of the condensed light beam 4 on the information track surface of the disk 1 is performed.

Further, the pitch of the information tracks is usually 2 μm or less, while the eccentricity between the center of rotation of the disk 1 and the center of the tracks is usually 100 μm or more. Therefore, in order to make the light beam 4 accurately follow the track, It is necessary to control (tracking servo) to move 4 in the radial direction of the disk 1 along the information track, and therefore the objective lens 5 is swung in the left-right direction in FIG.

Further, when the information track of the disk 1 is spiral, the light beam 4 moves in the radial direction of the disk 1 according to the track, and therefore it is necessary to control the optical head 3 itself to move at a slow speed.

As shown in FIG. 2, a lens position sensor (displacement detecting means) 6 for detecting the position of the objective lens 5 is provided for the movement of the optical head 3 to detect the movement amount of the irradiation position of the light beam 4. , That information is input to a compensation controller 7 (FIG. 7) such as a control ballast and a drive amplifier, and a signal necessary for moving the optical head 3 is output, whereby the optical head 3 is moved. The linear motor 8 for driving was driven.

<Problems to be Solved by the Invention> Therefore, if the gain of the control system is increased in order to reduce the control error of the control system that moves the optical head 3 or to improve the controllability against disturbance, Head 3
The rotational frequency component caused by the eccentricity of the disk 1 which is meaningless for the movement of the disk largely affects the drive signal of the linear motor 8, and the optical head 3 itself follows the shake of the objective lens 5 caused by the eccentricity of the disk 1. However, there is a problem that the power consumption for driving the optical head 3 is significantly increased due to the power consumption (reactive power consumption) for swinging the optical head 3.

Further, depending on the set control band, the eccentric disturbance to the tracking servo is increased.

The present invention has been made in view of such problems, and an object thereof is to increase the gain of a control system, and to obtain strong stability against external disturbances. A storage / playback device is provided.

<Means for Solving the Problems> In order to achieve the above object, an optical information storage / reproduction device according to the present invention rotates a disc-shaped information carrier having a concentric circle or spiral track form, In an optical information recording / reproducing apparatus for irradiating an information carrier with a light beam to record / reproduce information, an optical means for irradiating the light beam to record / reproduce information, and the optical beam provided in the optical means A light beam displacing means for displacing the light beam substantially at right angles to the track, a displacement detecting means for detecting a displacement amount of the light beam, and information on a deviation between a rotation center of the disc-shaped information carrier and a center of the track. Storing means and moving means for moving the optical means substantially at right angles to the track, and the information from the displacement detecting means and the information from the storing means are given to the moving means to move the moving means. To drive did.

<Operation> By adding the information from the displacement detection means and the information from the storage means, information having no eccentricity component of the disk can be obtained.

<Example> FIG. 1 is a schematic view showing an example of the present invention.

A motor 2 is fixed to a base 9 of the optical disk device, and a disk 1 on which information tracks are concentrically or spirally arranged is axially connected to the motor 2. A sliding member 10 is provided under the disk 1 in the radial direction, and the optical head 3 can slide on the sliding member 10. The moving means of the optical head 3 is a linear motor 8, which is a linear motor coil 8a fixed to the optical head 3 and a sliding member 1.
The linear motor magnet 8b is arranged in parallel with 0 and generates a thrust force on the linear motor coil 8a.

A schematic structure inside the optical head 3 is shown in FIG. The objective lens 5 is arranged so as to be movable in the vertical and horizontal directions, and the objective lens 5 focuses the light beam 4 generated in the optical head 3 on the disk 1. Focus servo is performed by moving the objective lens 5 in the vertical direction, and tracking servo is performed in the horizontal direction. The optical head 3 is provided with a lens position sensor 6 so that the position of the objective lens 9 in the tracking direction can be detected.

The lens position signal detected by the lens position sensor 6 is input to the memory 11 which is a storage unit.

The information stored in the memory 11 is preferably a deviation between the rotation center of the disk 1 and the center point of the track, that is, an eccentric component. Therefore, the processing of the microcomputer or the like causes a DC component cut or other disturbance. Remove.

Next, the information stored in the memory 11 is added to the real-time information 12 from the lens position sensor 6 at the addition point 13 and input to the compensation controller 7. Then, a signal required to move the optical head 3 is supplied to the linear motor coil.
8a, and the optical head 3 is moved.

 The operation of this embodiment having the above configuration will be described below.

The disk 1 is rotated by the motor 2 to apply the focus servo and tracking servo described above. At this time,
The lens position signal detected by the lens position sensor 6 has a waveform as shown in FIG. Due to the eccentricity between the center of rotation of the disk 1 and the center point of tracking, a substantially sinusoidal wave synchronized with the rotation cycle of the disk is obtained.

From this lens position signal, the DC component is cut and other disturbances are removed by processing of a microcomputer or the like to extract the eccentric component of the disk 1 and store it in the memory 11.

Next, the information stored in the memory 11 is added to the lens position signal 12 at the present time (real time) based on the tracking servo of the objective lens 5 detected by the lens position sensor 6 at the combining point 13 and the difference is calculated. Then, the information is input to the compensation controller 7, but the correction signal, which is a composite signal of the output of the memory 11 and the lens position signal, is a signal having no eccentricity component of the disk 1.

Then, the information from the compensation controller 7 is given to the linear motor coil 8a to move the optical head 3.

As described above, since the correction signal input to the compensation controller 7 is a signal having no eccentricity component of the disk 1, even if the gain of this control system is increased, an ineffective driving force due to the eccentricity component is not generated, A stable control system can be constructed by eliminating the influence of eccentricity.

 FIG. 4 is a schematic view showing another embodiment of the present invention.

Reference numeral 14 is a track control, which is connected to a tracking mechanism and controls a track jump when the number of tracks used for tracking servo or track access + track movement.

Reference numeral 15 is a displacement correction device that inputs a signal from the track control 14 and outputs a signal that imitates the movement of the objective lens 5 according to the signal.

Others are the same as the embodiment shown in FIG.

In the present embodiment having the above-described structure, when the irradiation position of the light beam is accessed to a track several tracks away from the current position track, the signal of FIG. 5 is applied to the tracking mechanism (light beam displacement means). .

By applying this signal to the tracking mechanism, the position of the objective lens 5 moves as shown in FIG.

The displacement correction device 15 inputs the signal shown in FIG. 5 and outputs a simulated lens position signal as shown in FIG. 6 by a secondary integrator or a microcomputer.

This simulated lens position signal is added at the addition point 13 with the real-time lens position signal 12 of the objective lens 5 and the signal output from the memory 11, and the combined signal (correction signal) thereof is input to the compensation controller 7. The linear motor 8 is driven by the signal output from the compensation controller 7.

Therefore, even during a track jump, the linear motor is not applied with a driving force by the lens position signal, and a stable track jump can be performed regardless of the response of the linear motor.

<Effects of the Invention> The optical information recording / reproducing apparatus according to the present invention stores the eccentricity component of the disk in the memory, adds it to the real-time lens position signal, and uses this signal (correction signal) as a drive signal, so that control is performed. Even if the gain of the system is increased, reactive power consumption does not occur, so it is easy to set the gain of the control system.
By increasing the control gain, it becomes stronger against external disturbance such as external vibration.

In addition, no disturbance is given to the tracking servo system during the track jump.

[Brief description of drawings]

1 is a schematic diagram showing an embodiment of the present invention, FIG. 2 is a schematic diagram showing the structure of an optical head, and FIG. 3 is a lens position sensor in which the horizontal axis represents time and the vertical axis represents lens position. A graph of the detected lens position signal, FIG. 4 is a schematic diagram showing another embodiment of the present invention, FIG. 5 is a signal applied when a track separated by a few + tracks is accessed, and FIG. FIG. 7 is a graph showing the movement of the objective lens when the signal of FIG. 5 is applied, where the axis is the time and the vertical axis is the lens position. FIG. 7 is a schematic diagram showing an example of a conventional optical information recording / reproducing apparatus. Is. 1 ... disk, 2 ... motor, 3 ... optical head, 4 ...
... light beam, 5 ... objective lens, 6 ... lens position sensor, 7 ... compensation controller, 8a ... linear motor coil, 8b
...... Linear motor magnet, 9 …… base, 11 …… memory, 12
…… Lens position signal, 13 …… Adding point, 14 …… Track control, 15 …… Displacement compensator.

Claims (2)

(57) [Claims] 1. An optical information recording / reproducing apparatus for recording / reproducing information by rotating a disc-shaped information carrier having a concentric circle or spiral track shape and irradiating the disc-shaped information carrier with a light beam. Optical means for irradiating a beam to record / reproduce information, a light beam displacement means provided in the optical means for displacing the light beam substantially at right angles to the track, and a displacement amount of the light beam is detected. A displacement detecting means, a storage means for storing information on a deviation between a rotation center of the disc-shaped information carrier and a center of the track, and a moving means for moving the optical means substantially at right angles to the track, An optical information recording / reproducing apparatus characterized in that the information from the displacement detecting means and the information from the storing means are given to the moving means to drive the moving means. 2. Displacement correction means for outputting information on a light beam displacement amount according to a drive signal of the light beam displacement means,
2. The optical information recording / reproducing apparatus according to claim 1, wherein the information from the displacement detecting means and the information from the storing means are added to the information from the displacement correcting means and are given to the moving means.