JPH04265525A - Head tilting mechanism for optical disk device - Google Patents

Abstract

PURPOSE:To obtain sufficient light convergence even when an optical disk medium is deformed regardless of the performance and the mounting accuracy of optical head components. CONSTITUTION:A moment having its start point at a pin 7 which is caused by the force of the difference between gravitation acting on a whole subbase plate 5 and pressing force of a spring 11 in the direction of an arrow I is applied to a cam 8 through a roller 10. The cam 8 is driven to rotate by a motor while acting against the moment. As a result, the roller 10 is moved up and down and the subbase plate 5 is rotated around the pin 7, which permits the optical axis of an optical head 2 to be tilted. Thus, by rotating the cam 8, the optical axis of the optical head 2 can be freely adjusted and accordingly, the sufficient light convergence is obtained regardless of the performance and the mounting accuracy of the optical head components even when the optical disk medium is deformed.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to an optical disc device.
In particular, it relates to the tilt mechanism of the optical head.

0002

2. Description of the Related Art In order to increase the recording density of an optical disc device, it is necessary to converge light emitted from an optical head onto an optical disc medium into a spot as small as possible. In order to improve the convergence of the light emitted from the optical head, it is necessary to improve the performance of the parts that make up the optical head, such as the lens and detector, and the accuracy of the mounting position of each part.
Furthermore, the precision of optical disk media must be improved.

0003

[Problems to be Solved by the Invention] However, the performance of components such as lenses and detectors that make up the optical head has been improved,
High-level technology is required to increase the precision of the mounting position of each component, which results in an increase in the cost of the device.

[0004] The optical disk medium has a structure as shown in FIGS. 4 and 5, and is composed of two media 101 and 102 bonded together at a central portion A and a peripheral portion B of the optical disk medium. As a result, the recording areas R of the media 101 and 102 may be raised (FIG. 4) or depressed (FIG. 5), which may hinder the convergence of light.

An object of the present invention is to solve these problems and to provide sufficient light convergence regardless of the performance and mounting accuracy of the optical head components and even if the optical disk medium is deformed. An object of the present invention is to provide a head tilt mechanism for an optical disc device.

[0006]

[Means for Solving the Problems] A head tilt mechanism for an optical disc device according to the first invention includes a base plate on which an optical disc medium is placed, an optical head for recording and reproducing information on the optical disc medium, and a drive mechanism thereof. A sub-base plate attached thereto, a pin rotatably supporting the sub-base plate on the base plate, a roller attached to the sub-base plate, and a cam abutting the roller and attached to the base plate. It is characterized by

A head tilt mechanism for an optical disc device according to a second aspect of the invention includes a base plate on which an optical disc medium is placed, and a sub-base plate on which an optical head and its drive mechanism are attached for recording and reproducing information on the optical disc medium. , a pin rotatably supporting the sub-base plate on the base plate, a roller attached to the sub-base plate, and a cam abutting the roller and attached to the base plate;
The present invention is characterized in that it includes a sensor that detects the rotation angle of the cam.

[0008]

[Example] Next, an example of the present invention will be described. Figure 1
An example of a head tilt mechanism of an optical disc device according to the present invention is shown in FIG. A spindle motor 17 for driving and rotating the optical disk medium 1 is mounted on the left end of the base plate 6. The optical head 2 is for recording and reproducing information on the medium 1, and is attached to a carriage 3, and the VCM 4 drives the carriage 3 to move the head 2 in the radial direction of the medium 1. These carriage 3 and VCM 4 are placed on a sub-base plate 5.

The sub-base plate 5 is connected to the base plate 6 by a pin 7 provided near the center of the base plate 6.
It is rotatably supported on top. Therefore, the sub-base plate 5 can be rotated in the directions of arrows I and II. 10 is
This is a roller provided at a position on the right side of the pin 7 of the sub-base plate 5. The cam 8 is attached to a shaft 9 supported on the base plate 6 and is in contact with a roller 10.

On the base plate 6, the pin 7 and the motor 1
A stopper 12 provided between the base plate 7 and the base plate 7 is used to determine the limit when the sub-base plate 5 rotates in the direction of the arrow I due to disturbance. On the base plate 6,
The spring 11 provided further to the right of the cam 8 is
It biases against the sub-base plate 5 and reduces the load on the cam 8.

FIG. 2 shows the drive section of the cam 8. A worm wheel 15 is attached to one end of the shaft 9 to which the cam 8 is attached, and a worm 14 rotated by a drive motor 13 meshes with the wheel 15. Therefore, when the motor 13 rotates, rotational torque is transmitted to the cam 8 via the worm 14 and the wheel 15. Further, a sensor 16 such as an encoder is attached to the other end of the shaft 9, and the rotation angle of the cam 8 is detected.

Next, the operation will be explained. A moment starting from the pin 7 is applied to the cam 8 through the roller 10 due to the difference between the gravity acting on the entire sub-base plate 5 and the pressing force of the spring 11 in the direction of the arrow 11 . Cam 8 is driven by motor 13 and rotates against this moment. As a result, the roller 10 moves up and down and the sub-base plate 5 rotates around the pin 7, so that the optical axis of the optical head 2 is tilted according to the rotation angle of the sub-base plate 5.

FIG. 3A shows a case where the roller 10 follows the rotation of the cam 8 and is pushed upward, and at this time the optical axis of the optical head 2 is tilted by +α degrees. Further, FIG. 3(B) shows a case where the cam 8 is in the initial state, the roller 10 is not moving either up or down, and the corrected optical axis of the optical head 2 is aligned with the initial optical axis. There is. Figure 3 (C
) shows a case where the roller 10 follows the rotation of the cam 8 and descends, and at this time the optical axis of the optical head 2 is tilted by −α degrees. That is, by rotating the cam 8, the optical axis of the optical head 2 can be adjusted freely, and therefore, sufficient light convergence is achieved regardless of the performance and mounting accuracy of the optical head components, and even if the optical disk medium is deformed. is obtained.

Further, since a sensor 16 is attached to the shaft 9 that rotates the cam 8, this sensor 16
The rotation angle of the cam 8 can be detected by this, and the detection result can be used to adjust the optical axis.

[0015]

As explained above, the head tilt mechanism of the optical disc device according to the first invention includes a base plate on which an optical disc medium is placed, an optical head for recording and reproducing information on the optical disc medium, and a drive mechanism thereof. The device includes an attached sub-base plate, a pin that rotatably supports the sub-base plate on the base plate, a roller attached to the sub-base plate, and a cam that comes into contact with the roller and is attached to the base plate. Therefore, with this head tilt mechanism, the optical axis of the optical head can be freely adjusted by rotating the cam, and therefore, regardless of the performance and installation accuracy of the optical head components, and even if the optical disk medium is deformed, sufficient light is provided. It is possible to obtain the convergence of

Further, the head tilt mechanism of the optical disk device according to the second invention further includes a sensor for detecting the rotation angle of the cam. Therefore, the rotation angle of the cam can be detected by this sensor, and the detection result can be used to adjust the optical axis, so that the optical axis can be adjusted more effectively.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a head tilt mechanism of an optical disc device of the present invention.

FIG. 2 is a perspective view showing a cam constituting the head tilt mechanism of FIG. 1 and a driving section thereof.

3 is a diagram showing the relationship between rotation of a cam and change in the optical axis of the optical head in the head tilt mechanism of FIG. 1. FIG.

FIG. 4 is a cross-sectional view showing an optical disc medium.

FIG. 5 is a sectional view showing an optical disc medium.

[Explanation of symbols]

1 Optical disc medium 2 Optical head 3 Carriage 4 VCM 5 Sub base plate 6 Base plate 7 Pin 8 Cam 9 Shaft 10 Roller 11 Spring 12 Stopper 13 Drive motor 14 Warm 15 Worm wheel 16 Sensor

Claims (2)

[Claims] 1. A base plate on which an optical disc medium is mounted, a sub-base plate to which an optical head and its drive mechanism for recording and reproducing information on the optical disc medium are attached, and the sub-base plate is rotatable on the base plate. A head tilt mechanism for an optical disc device, comprising: a pin supported on the sub-base plate; a roller attached to the sub-base plate; and a cam abutting the roller and attached to the base plate. 2. A base plate on which an optical disc medium is mounted, a sub-base plate to which an optical head and its driving mechanism for recording and reproducing information on the optical disc medium are attached, and the sub-base plate is rotatable on the base plate. an optical disc device comprising: a pin supported on the sub-base plate; a roller attached to the sub-base plate; a cam abutting the roller and attached to the base plate; and a sensor detecting the rotation angle of the cam. head tilt mechanism.