JPH0430646B2 - - 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.

Conventional structure and problems The elastic member of the optical pickup has sufficient elasticity, and when focus, tracking, etc. are not controlled, the optical axis of the objective lens and the optical axis of the light incident from the light source coincide. Therefore, a positioning function for supporting the objective lens at a predetermined position and a damping function for vibration of the objective lens are required.

Although metal leaf springs have excellent positioning functions, it is difficult to obtain elasticity in the two orthogonal directions of focusing and tracking, and the damping effect against vibrations of the objective lens is insufficient, so they do not have good control characteristics. It has a drawback that it cannot be obtained.

Further, rubber plate springs have the problem that they generate distortion when attached to a movable part, making it difficult to obtain an accurate positioning function.

Therefore, the present applicant proposed an elastic member for an optical pickup device as disclosed in Japanese Patent Application No. 58-62437 as a solution to the above-mentioned problems.

The configuration will be explained below using FIGS. 1 to 4.

FIG. 1 shows a plan view of the elastic member, and FIG. 2 shows a sectional front view. This elastic member has a ring-shaped portion 1 in the center, and thin plate-shaped spring portions 2a and 2b are provided on opposite sides of the ring-shaped portion 1. The opposing ends of the spring parts 2a, 2b are connected to each other by metal members 3a, 3b, and 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 parts 2a, 2b are approximately parallel to each other and are approximately symmetrical with respect to the ring-shaped member 1, and the metal members 3a, 3b are approximately perpendicular to the spring parts 2a, 2b and are approximately parallel to each other. It is.

3 and 4 show the elastic members shown in FIGS. 1 and 2 attached to 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 disk is shown. 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 metal ring 4 and the metal members 3a and 3b, which are rigid metal bodies, and there is no distortion of the elastic members during joining, as seen in conventional examples, so focus or tracking control is not performed. When not in use, a positioning function for supporting the objective lens 5a at a predetermined position can be obtained.

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.

However, in the elastic support member configured as described above, when attaching the metal ring 4 to the movable part 5, the coil axes of the tracking drive coils 8a and 8b may not coincide with the YY direction in the figure.

As a result, tracking drive coils 8a, 8b
The direction of the tracking driving force, in which the tracking driving magnets 9a and 9b act in cooperation with each other, is
This has the problem of causing a discrepancy with the disk radial direction XX and causing jitter.

OBJECT OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks of the conventional technology, and to have elasticity in two orthogonal directions for focus control and tracking control, and to have a damping effect during vibration, and also to have elasticity in two orthogonal directions for focus control and tracking control. It has a positioning function that accurately supports the objective lens in the position described when it is not working.
Another object of the present invention is to provide an elastic member for optical pickup that can prevent the occurrence of jitter due to tracking control by positioning a tracking drive coil, and can realize a smaller size and lower power consumption of the device.

Structure of the Invention The present invention houses an objective lens inside, and has a circumferential step at the upper and lower ends and a linear step formed on the outside of the circumferential step. A movable part equipped with a coil and a tracking coil,
A casing that holds the magnets that act on these coils arranged around the outer periphery of the movable part and a pair of substantially parallel thin rubber plate-shaped spring parts are connected at both ends with a metallic material, and about four sides thereof An elastic support member configured such that a metal ring having a straight line portion on the outer periphery is held by the thin plate spring portion is provided at a substantially central position of the shape, and the circumferential step portion at the upper and lower ends of the movable portion is , on the inner periphery of the metallic ring of each elastic support member,
The linear stepped portion engages with the linear portion of the metal ring and is fitted in an unrotatable state, and an elastic support member holding the movable portion in this manner is attached to the housing. be.

According to this configuration, as described above, the movable part is positioned at a position where the linear step part and the linear part engage, and is held by the elastic support member in an unrotatable state, so that the focus coil And the tracking coil can be easily directed in a predetermined direction.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 5 and 6 show an elastic member, and first, this elastic member will be explained.

This elastic member includes a metal ring 11 in the center having positioning fitting surfaces 12a and 12b on a part of its outer periphery, and thin plate-like spring portions 2a and 2b opposite to each other on both sides of the metal ring 11. will be established. The opposing ends of the spring parts 2a and 2b are connected to each other by metal members 3a and 3b. Further, the spring portions 2a and 2b are substantially parallel to each other and the metal ring 1
The metal member 3 is further arranged so as to be substantially orthogonal to the straight parts 12a and 12b of 1 and to be substantially symmetrical to each other.
a and 3b are substantially parallel to the spring portions 2a and 2b.

7 and 8 show the elastic members shown in FIGS. 5 and 6 attached to an optical pickup.

In FIGS. 7 and 8, 5 is an objective lens 5a.
6 is a housing of the entire 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 disk. In the figure, XX indicates the radial direction of recording tracking on the disk 10, YY indicates the tangential direction of the recording track, 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 has a metal ring 11
The positioning fitting surfaces 12a, 12b are the step parts 13a, 1 which are positioning fitting parts provided on the movable part 5.
3b, and is joined to the circumferential stepped portion 5b, and is joined to the stepped portions 6a, 6b provided on the housing 6 by the plate-like portions 3a, 3b, respectively.

The stepped portions 13a, 13b are formed substantially parallel to the tracking drive coils 8a, 8b.

Further, the step portions 6a and 6b are formed so as to be substantially parallel to the XX direction.

With the above configuration, the elastic member, the movable part, and the housing 6 of the optical pickup are joined by the metallic ring 11, which is a rigid metallic body, and the metallic members 3a, 3b. Since distortion of the elastic member does not occur at times, a positioning function for supporting the objective lens 5a at a predetermined position can be obtained when focus or tracking control is not performed.

In addition, the spring parts 2a and 2b are made of synthetic rubber.
By forming a thin plate shape with the longitudinal direction in the YY direction, it is possible to realize an elastic member that 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. .

Furthermore, the positioning fitting surface 1 of the metal ring 11
2a and 12b perform positioning within the XY plane, tracking drive coils 8a and 8b
The coil axis of almost coincides with the YY direction.

Therefore, since the direction of the tracking drive force exerted by the tracking drive coils 8a, 8b and the tracking drive magnets 9a, 9b in cooperation with each other substantially coincides with the disk radial direction XX, it is possible to prevent jitter from occurring due to tracking control.

Furthermore, since the movable part 5 is driven in parallel to the XX direction, the gap between the tracking drive magnets 9a, 9b and the tracking drive coils 8a, 8b can be reduced, making it possible to reduce the size of the device and reduce power consumption. It is possible to provide an elastic member for use.

In addition, as another embodiment of the present invention, the same effect can be obtained even if the metal members 3a, 3b are cylindrical. In addition, these spring parts 2a, 2b, a ring 11, a metal member 3a, which is a positioning part,
3b by integral molding, positioning accuracy is improved.

Effects of the Invention As described above, according to the present invention, the present invention has elasticity in two orthogonal directions for tracking control and focus control, and also has a damping effect on vibrations of the objective lens. It has a positioning function that accurately supports the objective lens in a predetermined position when the objective lens is not in use, and by positioning the tracking drive coil, it prevents jitter from occurring due to tracking control, and also realizes a smaller size and lower power consumption of the device. Accordingly, it is possible to provide an elastic member for optical pickup.

[Brief explanation of drawings]

FIG. 1 is a plan view of an elastic member of a conventional optical pickup device, and FIG. 2 is a sectional front view of the same elastic member.
Figures 3 and 4 are a plan view and a sectional front view of the device,
FIG. 5 is a plan view of an elastic member according to an embodiment of the present invention;
FIG. 6 is a sectional front view of the elastic member, and FIGS. 7 and 8 are a plan view and a sectional front view of the device. 2a, 2b...Thin plate-like spring portion, 3a, 3b...
...metallic member, 5...movable part, 6...casing, 8
a, 8b...Tracking drive coil, 11...
Metal rings, 12a, 12b...straight portions.

Claims (1)

[Claims] 1. An objective lens is housed inside, and the upper and lower ends have a circumferential step and a linear step formed outside the circumferential step. A movable part in which a focus coil and a tracking coil are arranged; a housing that holds a magnet acting on the focus coil and the tracking coil arranged around the outer periphery of the movable part; and a pair of substantially parallel rubber parts. Both ends of a thin plate-shaped spring part are connected by a metallic material, and a metal ring having a straight part on the outer periphery is held by the thin plate-shaped spring part at a substantially central position of the substantially four-sided shape. a support member, the pair of elastic support members are locked to the housing via the metallic material so as to face each other in a substantially parallel state; The circumferential stepped portion is fitted onto the inner periphery of the metallic ring of each of the elastic support members in a state in which the linear stepped portion engages with the linear portion of the metallic ring and cannot rotate. is supported by the elastic support member, and the focus coil and the tracking coil of the movable part are oriented in a predetermined direction at the engagement position of the linear step part and the linear part, An optical pickup device disposed in the movable part in a specified positional relationship with respect to the linear stepped part of the movable part.