JPH0349136B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention uses a laser or the like as a light source to drive an objective lens in an optical recording/reproducing device that records or reproduces information on a disc-shaped information recording medium (hereinafter referred to as a disk). The present invention relates to an optical pickup device that performs focus and tracking control.

Construction of conventional examples and their problems As supporting members for the elastic members used in optical pickups, for example, two-way leaf springs made of synthetic rubber or metal leaf springs as seen in Japanese Patent Application Laid-open No. 57-27443 are used. There is.

On the other hand, for the elastic member of the optical pickup,
Not only does it have sufficient elasticity, but it also has a positioning function that supports the objective lens in a predetermined position so that the optical axis of the objective lens and the incident optical axis from the light source match when no control such as focus or tracking is performed, and vibration of the objective lens. A damping function is required for

Although metal leaf springs have an excellent positioning function, they are difficult to obtain elasticity in the two orthogonal directions of focusing and tracking.
As seen in -27443, the focusing and tracking leaf springs must be provided separately and independently. Therefore, the optical pickup becomes larger. Another drawback is that good control characteristics cannot be obtained because the damping effect against vibrations of the objective lens is insufficient.

In addition, in the case of the two-way leaf spring of a synthetic rubber bag, although it is excellent in terms of elasticity and damping effect against vibration, it is difficult to position the objective lens in a predetermined position when focus, tracking, etc. are not controlled. In terms of functionality, it's not enough. That is, it is difficult to obtain a positioning function on the order of μm due to the distortion that occurs in the synthetic rubber when the synthetic rubber bag two-way leaf spring is attached to the objective lens and the housing of the optical pickup.

Purpose of the Invention The purpose of the present invention is to eliminate the above-mentioned conventional drawbacks, and to
An object of the present invention is to provide an optical pickup device using an elastic member that has elasticity in the direction, has a damping effect when vibrating, and has an objective lens positioning function.

Structure of the Invention The present invention includes a movable part housing an objective lens, a focus coil and a tracking coil provided around the movable part, a magnet acting on these coils, and a movable part, the coil, and the tracking coil. The magnet is provided with a casing that stores a magnet and is open at the top and bottom, and a rubber elastic member whose central part is attached to the movable part and whose both ends are fixed to the opening of the casing. The elastic member includes a ring-shaped part in the center, thin plate-shaped spring parts facing each other on both sides, a metal ring provided on the ring-shaped part and attached to the movable part, and end parts of the thin plate-shaped spring parts. This optical pickup device is provided with a member that is coupled to the casing and is attached to the open end of the casing.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 and FIG. 2 show an elastic member, and first, this elastic member will be explained. This elastic member has a ring-shaped part 1 in the center, and thin plate-shaped spring parts 2 facing each other on both sides of the ring-shaped part 1.
a and 2b are provided. The opposing ends of the spring parts 2a and 2b are connected to each other by metal members 3a and 3b, and furthermore, a metal ring 4 is fixed to the inside of the ring-shaped part 1. The spring parts 2a, 2b and the ring-shaped part 1 are integrally molded from synthetic rubber. The spring portions 2a and 2b are approximately parallel to each other and approximately symmetrical with respect to the ring-shaped member 1;
The metal members 3a, 3b are substantially perpendicular to the spring portions 2a, 2b, and are substantially parallel to each other.

3 and 4 show the elastic members shown in FIGS. 1 and 2 installed in an optical pickup. Figure 3,
In FIG. 4, 5 is a movable part that houses the objective lens 5a, 6 is the entire housing of the optical pickup, 7 is a focus drive coil, 8a and 8b are tracking drive coils, 9a and 9b are tracking drive magnets, and 10 is a Each has its own disk. Further, in the figure, XX indicates the radial direction of the recording track on the disk 10, YY indicates the tangential direction of the recording track, and ZZ indicates the thickness direction of the disk 10. Elastic members are also provided below and are given the same numbers as those above.

The pair of upper and lower elastic members are joined to a circumferential stepped portion 5b provided on the movable portion 5 by the metal ring 4, and connected to stepped portions 6a, 6b provided in the housing 6 by plate-like members 3a, 3b. are joined to each other.

With the above configuration, the connection between the elastic member, the movable part 5, and the housing 6 of the optical pickup is as follows.
This is done using the ring-shaped parts 2a, 2b and the plate-shaped members 3a, 3b, which are rigid metal bodies, and since distortion of the elastic members does not occur during joining as seen in conventional examples, focus or tracking control can be performed. A positioning function is provided to support the objective lens 5a at a predetermined position when the objective lens 5a is not positioned.

In addition, the spring parts 2a and 2b are made of synthetic rubber.
An elastic support for optical pickup that has a thin plate shape with the longitudinal direction in the YY direction, so that it has elasticity in both the XX and ZZ directions, that is, the directions for focus control and tracking control, and also has a damping effect against vibrations of the objective lens. It is possible to provide parts.

In addition, as another embodiment of the present invention, the plate-shaped member 3
A similar effect can be obtained by making a and 3b cylindrical. In addition, positioning accuracy is improved by integrally forming the spring parts 2a, 2b and the ring 4 and plate-like members 3a, 3b, which are positioning parts, by integral molding.

Effects of the Invention As described above, the present invention provides elasticity in the two orthogonal directions of tracking control and focus control, and also has a damping effect on vibrations of the objective lens, and furthermore, focus control or tracking control is performed. It is possible to provide an elastic member for optical pickup having a positioning function to accurately support an objective lens in a predetermined position when the objective lens is not in use.

[Brief explanation of drawings]

FIG. 1 is a plan view of an elastic member of an optical pickup device according to an embodiment of the present invention, FIG. 2 is a sectional front view of the same elastic member, and FIGS. 3 and 4 are a plan view and a sectional view of the same device. It is a front view. 2a, 2b...Thin spring part made of synthetic rubber, 4...Metallic ring, 3a, 3b...Metallic plate member, 5...Movable part housing objective lens, 6...Light Pickup casing.

Claims (1)

[Claims] 1 A movable part that houses an objective lens, a focus coil and a tracking coil provided around this movable part, magnets that act on these coils, and something that houses the movable part, the coil, and the magnet. a casing that is open at the top and bottom; and a rubber elastic member whose central part is attached to the movable part and whose both ends are fixed to the opening of the casing. a ring-shaped part, a thin plate-shaped spring part facing each other on both sides, a metal ring provided on the ring-shaped part and attached to the movable part, and connecting the ends of the thin plate-shaped spring part to each other. An optical pickup device comprising a member attached to an open end of the casing.