JPH0369024A - Optical system drive device - Google Patents

Abstract

PURPOSE:To accurately fix a neutral position holding member and to smoothly slide and turn a movable member so as to stabilize servo characteristics by specifically constructing the neutral position holding member constituted of an elastic material to be fixed to the movable member. CONSTITUTION:The movable member 21 similar to the movable member of the prior art is vertically slid and laterally turned around a supporting shaft 33. The neutral position holding member 45 consisting of Si rubber has a part 45a to be fitted to the outer periphery of a bearing 23 of the movable member 21 and a part 45b to be fitted to a large rubber stopping pin 29 around the bearing 23, and the front end of the pin 29 is on the inner peripheral side than the position symmetrical with an objective lens 22. The holding member is fixed to the movable member 21 by the fitting part 45a and is accurately positioned and fixed to the movable member 21 by the fitting part 45b. The pressurized contact of the inside diameter surface of the bearing with the supporting shaft and the extreme inclination of the movable member are prevented by this constitution and the movable member is smoothly slid and turned, by which the servo characteristics are stabilized. The neutral holding member 45 is fixed by a supporting member 46 to a base plate 28.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical system drive device suitably used in, for example, an optical information recording/reproducing device.

[Prior Art] Fig. 2 shows an exploded perspective view of a conventional objective lens driving device.

In FIG. 2, 1 indicates a movable member. The movable member is provided with a bearing 3 at its center. Further, the movable member 1 is provided with an objective lens e2, and a balance weight 4 is fixedly provided at a position 5 substantially symmetrical to the lens e2 with the bearing 3 as the center. Further, a focus coil 6 is wound and fixed on the outer circumference of the movable member 1 for driving the member 1 in the two directions shown in the figure, and a focus coil 6 is wound and fixed on the outer circumference of the movable member 1 to drive the member 1 in the y direction shown in the figure. Tracking coils 7m+7bt7c+7d for driving 1 are fixedly attached.

The yoke 8 has a base 89 made of a ferromagnetic material, an inner yoke portion 10m, 10b and an outer yoke portion 1 also made of a ferromagnetic material.
1a*11b, and the outer yoke portion 11a.

Permanent magnets 12 m * 12 fixed to each of 11b
b, and a support shaft 13 press-fitted into the base portion 9.

Inner yoke portion 10a I 10b and permanent magnet 12&.

A stain magnetic force is generated by energizing the focus coil 6 and tracking coils 7a to 7d in the magnetic field generated in the gap between the movable member 12b and the support part 13, and the movable member 1 slides up and down and/or moves left and right around the support part 13. Do a mouthful.

In order to return this movable member 1i to the neutral position, conventionally, for example, a barbed part 14 was provided at one end of the balance weight 4, and an elastic member 15 such as silicone rubber was fitted and fixed into the barbed part 14. 1 The other end of the elastic member 15 is the support member 1
6 and the support member 16 is fixed to the yoke 8.

[Problem to be solved by the invention]

However, in the above case, due to the poor adhesion of silicone rubber, simply fitting the elastic member 15 into the balance weight 4 will cause the elastic member 15 to rotate around the balance weight 4 when the movable member 1 is driven. There was a drawback that it would shift. For this reason, a method of fixing the balance weight 4 and the elastic member 15 by baking is considered, but this method eliminates misalignment in the rotational direction of the movable member 1 and the balance weight 4, and the rotational direction of the elastic member 15. Difficult to fix.

Furthermore, as the connection position between the elastic member 15 and the movable member 1 moves toward the outer circumference of the movable member 1, the inner diameter surface of the bearing 3 becomes stronger with respect to the support shaft 13 due to the pulling force caused by the elasticity of the elastic member 15. If the movable member 1 is not easily pressed, the movable member 1 is likely to tilt significantly. Therefore, there is a problem that the movable member l cannot slide and rotate smoothly and the servo characteristics become unstable.
It was.

Therefore, it is required to accurately position and fix the movable member 1 and the elastic member 15.

〔the purpose〕

The present invention has been made in view of the problems of the prior art described above, and its purpose is to provide a neutral lens that can accurately return and maintain the objective lens position to the neutral position, and that can smoothly slide and rotate. An object of the present invention is to provide an optical system drive device equipped with a position holding mechanism.

[Means to solve the problem]

According to the present invention, the above object includes a movable MJ member that holds an optical system, a drive means that slides and/or rotates the movable member, and a support that supports the sliding and/or rotation of the movable member. An optical system drive device comprising a shaft, a base to which the support shaft is fixed, and a neutral position holding member having an elastic member that holds the movable member at a neutral position; one end of the neutral position holding member is It is elastically wound and fixed to the outer periphery of a bearing provided on a movable member that pairs with the support shaft, and a recess or a protrusion provided on the neutral position holding member is fitted in the vicinity of the bearing. 6,
The other end of the neutral position holding member is fixed to the base directly or via a joining member, and this is achieved by a moving device for the optical system 4.

[Effect]

By using the above means, the elastic member (neutral position holding member) can be fixed to the movable member with high precision, and the conventional problems of pressure contact on the inner diameter surface of the bearing with respect to the support shaft and significant inclination of the movable member can be prevented. can. Therefore, the movable member can slide and rotate smoothly, and the servo characteristics are stabilized.

〔Example〕

Hereinafter, embodiments of the present invention will be described specifically and in detail based on the drawings.

FIG. 1 is an exploded perspective view showing an optical system driving device of the present invention. However, FIG. 1 also shows a sectional view taken along line AA of the movable member.

As shown in FIG. 1, a bearing portion 2 is provided at the center of the movable member 21.
3 are provided, and 6, the objective lens, e22, and balance weight 24 are each fixedly provided at symmetrical positions with the bearing portion 23 as the center. Further, on the outer circumference of the movable member 21, there is a focus coil 2 for driving in the vertical direction in the figure.
6 and tracking coils 27a for driving in the left and right directions.
27d is wound and glued.

The ferromagnetic yokes include inner yoke parts 30a, 30b, outer yoke parts 31a*3lb, and outer yoke part 311.
32 m of permanent black stone fixed to each of 131b, 3
2b is formed and fixed to the carriage 28, which is a base, by screws, adhesive, or the like. In this embodiment, the second
Each yoke and support 11d are different from the diagram.
133 and a support member 46 that supports the elastic member 45 is fixed.

In the optical system driving device configured in this manner, the movable member 21 vertically slides and/or horizontally rotates around the support @33 by electromagnetic force, similar to the conventional example shown in FIG. An elastic member 45 is used as the neutral position holding mechanism, and this elastic member is made of an elastic material such as silicone rubber. As shown in the figure, the shape is such that the length of the elastic member is sufficient even when the movable member 21 slides up and down and rotates left and right, so that the inner diameter surface of the bearing part 23 is not pressed against the support shaft 33, and the movable member 21
It has a structure in which the inclination of .

In addition, in the illustrated case, the elastic member 45 includes a fitting portion 45m that is fitted into the outer circumferential portion of the bearing portion 23 with an inner diameter that is the same as or smaller than the outer circumferential shape of the bearing portion 23, and a fitting portion 45m that is fitted into the outer circumferential portion of the bearing portion 23.
3 at a substantially symmetrical position to the objective lens 22, and at this symmetrical position, it is fitted into a rubber stopper pin part 29, which is a convex protruding part provided on the bearing side, that is, on the inner peripheral side, and has a thick tip. A fitting part 45b is provided. The fitting portion 45b is fixed to the movable member 21 at the fitting portion 451.
It is precisely positioned and fixed to the movable member 21.

The configuration of this embodiment is called a separation optical system, and the semiconductor laser, sensor, optical components, etc. that make up the laser beam (not shown) are provided outside the carrier and the laser beam 28, and a small amount of light is emitted from the semiconductor laser. The Rede beam passes through the beam hole B36, passes through the beam hole A35 by a bending mirror (not shown), is condensed by the objective lens 22 onto an information recording medium (not shown), and then,
Depending on the route of pick-up, the reflected light will return to the head.

Although the neutral position holding member in this embodiment uses a silicone saw, it is not limited to this, and any elastic member that has excellent damping properties and whose performance changes little depending on environmental conditions may be used.

Further, in this embodiment, in order to fix the elastic member to the movable member, the elastic member is fitted into the outer periphery of the bearing provided on the movable member, but the present invention is not limited to this. It may also be of a fitted type.

However, this position is the position of the rubber fixing pin provided to position the elastic member to the movable member, and the position is approximately symmetrical to the objective lens with the bearing of the movable member of the housing as the center. The bearing side, that is, the inner peripheral side in the radial direction is desirable.

Further, the positions of the pins, holes, and rubber fixing pins are not limited to the opposite side of the objective lens with the bearing as the center, for example, the center of the objective lens 22 and the center of the bearing part 23,
It may be provided at a position perpendicular to a straight line connecting the centers of the balance weights 24, or at a position JL-%-H when the movable member is viewed from below as shown in FIG.

Further, the shape of the elastic member is not limited to that of this embodiment.

Although the elastic member is fixed to the base 28 via the support member, the elastic member is not limited to this, and may be fixed to a yoke or a magnet.

〔Effect of the invention〕

As explained above, one end of the elastic member is provided on the movable member as a method of fixing the neutral position holding member, which is composed of an elastic member for returning and holding the movable member to the neutral position, to the movable member. It is wound and fixed on the outer part of the bearing, and the fixed position is approximately symmetrical to the objective lens with the bearing as the center, and a convex part or a concave part is provided on the bearing side (inner peripheral side) in this symmetrical position, or By providing a convex portion or a concave portion near the bearing and fitting a corresponding concave portion or convex portion provided on the elastic member side, the elastic member (neutral position holding member) t can be held against the movable member. - It can be fixed with high precision, and it is possible to prevent pressure contact of the inner diameter surface of the bearing with respect to the support shaft and significant inclination of the movable member. Therefore, the movable member can slide and rotate smoothly, and the thermal characteristics are stabilized.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing an optical system drive device of the present invention, FIG. 2 is an exploded perspective view showing a conventional objective lens drive device, and FIG. 3 is a movable member showing another embodiment of the present invention. It is a top view when seen from below. 21... Movable member, 23... Bearing part, 33... Support shaft, 45... Elastic member, 45m... Fitting part, 46
...Supporting member.

Claims (1)

[Claims] (1) A movable member that holds an optical system, a drive means that slides and/or rotates the movable member, a support shaft that supports the sliding and/or rotation of the movable member, and a support shaft that supports the sliding and/or rotation of the movable member. In an optical system drive device comprising a fixed base and a neutral position holding member having an elastic member that holds the movable member at a neutral position; one end of the neutral position holding member is paired with the support shaft. The movable member is elastically wound and fixed around the outer circumference of a bearing, and a convex portion or a concave portion in the vicinity of the bearing is fitted with a concave portion or a convex portion provided on the neutral position holding member. an optical system driving device, wherein the other end of the neutral position holding member is fixed to the base directly or via a joining member.