JPS60136042A - Tracking mechanism of optical disk - Google Patents

Abstract

PURPOSE:To operate a fine access mechanism stably by providing a voice coil motor for adjusting spindle movement and a driving motor which rotates a spindle shaft in a free coupling state. CONSTITUTION:A spindle 9 is supported rotatably at one terminal of a spring- type support member 11. The support member 11 operates to hold the center point of an optical disk 1 in an oscillatory state at fine distance in parallel to the moving direction of an optical head 2'. The torque of a spindle driving motor 12 is transmitted to a universal joint 13. The driving signal for a voice coil motor 14 for driving the spindle is obtained from the detection signal obtained from the optical head 2'. In this case, a large-sized motor is usable as said voice coil motor, so the motor is stable against disturbance and follows up the eccentricity and the motion of the optical disk zone.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a tracking mechanism in an optical recording/reproducing device such as an optical disk device or a magneto-optical disk device. This invention relates to a tracking mechanism that adjusts the movement of an axis.

(b) Prior art and problems A conventional example will be explained with reference to the drawings. FIG. 1 is a schematic diagram and a block diagram showing a tracking mechanism in a conventional optical disk device. In the figure, 1 is an optical disk, 2 is an optical head, and the access method in conventional optical disk devices is a coarse access mechanism that accesses a large range of the optical disk surface of the optical disk L, and a so-called so-called track misalignment that attempts to correct track deviation including track eccentricity. Consists of #coarse access mechanism for tracking. The coarse access mechanism consists of a coarse motion carriage 3 and a coarse motion voice coil motor 4 that drives it, and the fine access mechanism supports the optical head 2 on the coarse motion carriage 8 with an elastic body 5 to improve positioning resolution. The optical radar 2 is driven by a fine voice coil motor 6 fixed to a moving carriage 8. A tracking position error signal is obtained from the detection signal obtained from the optical head 2 via a differential amplifier 7, and this signal is fed back to the fine motion voice coil motor 6 via a phase compensation circuit 8.

However, this mechanism supported by the elastic body 5 is unstable against external disturbances. Further, when the coarse access mechanism accesses at high speed, the operation of the fine access mechanism becomes unstable and tracking is not performed properly.

(C) Object of the Invention In view of the above-mentioned drawbacks of the conventional art, it is an object of the present invention to provide a tracking mechanism that stably operates a fine access mechanism in an optical recording/reproducing device.

(d) Structure and object of the invention According to the present invention, a spindle that supports and rotates an optical disk, a voice coil motor that moves and adjusts the spindle in a direction perpendicular to the spindle axis, and a universal joint that controls the rotation of the spindle axis. The present invention is achieved by providing an optical disc tracking mechanism comprising a drive motor that performs a state-of-motion operation, and which corrects tracking deviation of the optical disc by operating the voice coil motor.

(e) Embodiments of the Invention Examples of the present invention will be described below with reference to the drawings. In this figure, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and redundant explanation thereof will be omitted.

FIG. 2 shows a cross-sectional perspective view of essential parts of the tracking mechanism for an optical disc according to the present invention.

In the figure, i denotes an optical head without a tracking mechanism, which is mounted on a coarse movement carriage 8 and driven by a coarse movement voice coil motor 4 in the radial direction of the optical disk l. A spindle 9 supports and rotates the optical disc 1, and is rotatably supported at one end of a spring-like support member 11.
A mounting mechanism is provided at the other end of the spring-like support member 11 and is fixed to a frame (not shown) of the optical disk device. The action of the spring-like support member 11 is that the optical fiber 1 supported by the spindle 9
The center point of the optical head 2' is held swingably at a minute distance in a direction parallel to the moving direction of the optical head 2'.

Reference numeral 14 denotes a voice coil motor for driving a spindle, and a bobbin 10 serving as a thrust generating portion thereof is connected to the spindle 9. 12 is a spindle drive motor, and torque transmission to the spindle 9 is performed by a universal joint 13 indicated by a broken line frame. In this example, a hinuteresis coupling that transmits torque in a non-contact state is shown within the dashed line frame, but if the eccentricity is too thick (if not, a bellows type coupling (not shown), a flexible universal joint, or a flexible elastic Couplings of members can also be used because the stress generated is small.

The third figure shows a block diagram of the main parts of the tracking mechanism of the optical disc according to the present invention.

The differential amplifier 7 uses the detection signal obtained from the optical head 2'.
A tracking error signal is obtained through a phase compensation circuit 8', and this signal is sufficiently amplified by a phase compensation circuit 8' to be used as a drive signal for a voice coil motor 14 for driving a spindle.

The optical head 2' obtains a defocus signal from the detection signal, and can focus the objective lens (not shown) of the optical head 2' along the optical axis using conventional means using a small voice coil motor. From this, the influence of the fine motion of the phototisph in the disk and perpendicular directions is resolved.

(f) Effects of the Invention As explained in detail above, according to the optical disk tracking mechanism according to the present invention, the voice coil motor for driving the spindle can be as large as space allows, and the thrust can be strengthened, thereby reducing disturbance.

It has the effect of being stable and able to follow the large eccentricity of the optical disk and the movement of a relatively high frequency band.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram and block diagram of a tracking mechanism of a conventional optical disk device; FIG. 2 is a cross-sectional perspective view of a main part of an optical disk tracking mechanism according to the present invention;
Figure iJIJ8 shows a block diagram of the main parts of the tracking mechanism of the optical disc according to the present invention. In the figure, 1 is an optical disk, 2.2' is an optical head, and 8
1 is a coarse motion carriage, 4 is a coarse motion voice coil motor, 9 is a spindle, 10 is a bobbin, 11 is a spring-like support member, 1
2 is a spindle drive motor, 1B is a universal joint, and 14 is a spindle drive voice coil motor. Figure 1 Figure 2 IJ 12 Figure 3

Claims (1)

[Claims] It is composed of a spindle that supports and rotates an optical disk, a voice coil motor that moves and adjusts the spindle in a direction perpendicular to the spindle axis, and a drive motor that rotates the spindle axis in a universal joint state, and is capable of tracking the optical disk. A tracking mechanism for an optical disc, characterized in that the deviation is corrected by the operation of the voice coil motor.