JPH08315379A - Optical head actuator - Google Patents

Abstract

PURPOSE: To obtain an excellent vibration damping characteristic by forming an optical head actuator which has a vibration damping material which is housed in a recessed part and damps the vibration of a moving piece and providing this recessed part with a prescribed volume to house a prescribed amt. of the vibration damping material. CONSTITUTION: Silicone in liquid state is injected into the recessed part 12b in such a manner that the recessed part 12 is filled nearly full therewith. In succession, a lens holder 21 is so moved as to attain the state of an initial position in, for example, a focus direction, namely, the moving piece 21c is inserted therein. Next, the silicone in liquid state within the recessed part 12b housing the silicone in liquid state in the recessed part 12b is irradiated with UV rays to form the vibration damping material 40 consisting of the gelled silicone (silicone gel). The unnecessary vibration generated in the case where the optical head part 20 moves in the focus direction and the tracking direction moves is absorbed by the vibration damping material 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head actuator for driving an optical head including an objective lens in an optical pickup device of an optical disk drive device in the focus and tracking directions.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a conventional optical head actuator disclosed in Japanese Patent Laid-Open No. 7-37261. In FIG. 2, this optical head actuator is called a biaxial actuator, and is called a base unit 50.
, The optical head portion 60, and the plurality of suspension wires 7
0. The base portion 50 has a magnet 51
A fixed magnet portion 51 including a and a yoke 51b and a wire fixing block 52 are provided. The optical head unit 60 includes an objective lens 62 provided on a lens holder 61,
A pair of tracking coils 63 and a focusing coil 64 are provided, and a plurality of suspension wires 70 are provided.
It is movably supported by the wire fixing block 52 via. The fixed magnet portion 51 of the base portion 50 and the pair of tracking coils 63 and focusing coil 64 of the optical head portion 60 constitute a driving device. The suspension wire 70 is composed of a wire having elasticity and conductivity, and functions as a supporting member of the optical head unit 60 and also the tracking coil 6 is used.
3 as well as a member for electrically connecting to the focusing coil 64. And the tracking coil 63
Also, the focusing coil 64 is energized, and the optical head unit 60 is moved in the focusing direction (indicated by an arrow FC in the drawing) and in the tracking direction (indicated by an arrow TR in the drawing) by a magnetic flux action between the coil and the fixed magnet unit 51. ) To
Adjust the focus and tracking of the objective lens 62.

[0003]

By the way, in the conventional optical head actuator of this type including the example shown in FIG. 2, in addition to the vibration of the optical disk drive device itself in which the optical head actuator is used, the optical head portion is moved in the focus direction. And the vibration mainly occurs in the focus and tracking directions due to the movement in the tracking direction. This vibration causes a focus error and a tracking error, which causes a problem that the optical disc cannot be read accurately. Moreover, since this vibration tends to continue for a certain period of time once it occurs, there is a possibility that the focus error and the tracking error may continue for a long time once the vibration occurs. Above all, the vibration in the tracking direction has a relatively large amplitude, which is a problem. Therefore, the optical head actuator is required to have a vibration-proof property of the optical head portion. Here, regarding the anti-vibration property of the optical head actuator, it is necessary not only to sufficiently suppress the above-mentioned unnecessary vibration but also to damp the vibration as quickly as possible in response to the occurrence of the vibration. Since it is required that it should not interfere with the normal operation of the head portion, it is desired to have excellent vibration damping characteristics that meet all of these requirements.

The object of the present invention is to have excellent vibration damping properties,
An object is to provide an optical head actuator that is easy to assemble and has a simple structure.

[0005]

According to the present invention, a base portion, a plurality of elastic suspension wires each having one end fixed to a wire fixing block provided on the base portion, and an objective lens are included, An optical head unit fixed to each of the other ends of the plurality of suspension wires and movably supported by the base unit via the plurality of suspension wires; and an optical head provided on the base unit and the optical head unit. An optical head actuator having a drive device for driving the optical pickup unit in a focus direction and a tracking direction, the optical head actuator being provided at a portion of the optical head portion facing the wire fixing block so as to extend from there to the wire fixing block. A movable piece that moves together with the optical head portion, and at least an end portion of the movable piece with respect to a moving range of the movable piece. The wire fixing block has a concave portion formed to surround the wire fixing block, and a damping material housed in the concave portion for suppressing vibration of the movable piece. The concave portion has a predetermined amount of the vibration damping material. An optical head actuator is obtained which has a predetermined volume so as to accommodate a material.

According to the present invention, it is also possible to obtain the optical head actuator having a preliminary concave portion which is formed in the wire fixing block adjacent to the concave portion and accommodates an excess amount of the damping material overflowing from the concave portion.

Further, according to the present invention, the optical head portion has a lens holder for holding the objective lens, and the movable piece is formed in an inverted L shape by a part of the lens holder. An actuator is obtained.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical head actuator according to an embodiment of the present invention will be described below with reference to the drawings.

1 (a) and 1 (b) are a top view and a vertical sectional view showing a main part of an optical head actuator according to the present embodiment. 1A and 1B, the present optical head actuator includes a base portion 10 and a base portion 1.
Each of the plurality of suspension wires 30 including the plurality of (four in this embodiment) suspension wires 30 having elasticity, one end of which is fixed to the wire fixing block 12 provided at 0, and the plurality of suspension wires 30 including the objective lens 22. An optical head portion 20 fixed to the end and movably supported on the base portion 10 via a plurality of suspension wires 30;
0 and the optical head unit 20 and a drive device described later for driving the optical head unit 10 in the focus direction (indicated by arrow FC in the figure) and the tracking direction (indicated by arrow TR in the figure). There is.

The base 10 comprises a plate-shaped base 11, a wire fixing block 12 fixed to the base 11 by screws 13, a magnet 14a and a yoke 14b, respectively.
And a pair of caps 15 attached to the wire fixing block 12. Each of the pair of caps 15 has a U-shaped cross section, and is fitted and attached from the outside of both side portions (upper and lower portions in the drawing) of the wire fixing block 12. And
The wire fixing block 12 is formed by the parallel pair of the U-shape.
Each of the four suspension wires 30 on the side covers a region 12a near each fixed end (in FIG. 1A, only the upper two positions are shown). The pair of caps 15 is a region 1 near the fixed end.
It is intended to cover a damping material (not shown) filled in 2a.

The optical head portion 20 has a substantially annular shape which defines a hole portion 21a, and a lens holder 21 for holding the objective lens 22 at the ring portion (the right side of the ring portion in the drawing) and the hole portion 2 are provided.
Focusing coil 23 fixed to the inner surface of 1a and penetrated by one of the pair of fixed magnet portions 14 of the base portion 10.
And a pair of fixed magnet portions 14 that are fixed to the side surfaces of the focusing coil 23 and are sandwiched between a pair of fixed magnet portions 14 (however, one fixed magnet portion 14 has a part of the focusing coil 23 interposed therebetween). And a tracking coil 24. The optical head unit 20 is fixed to both ends (upper and lower parts in the figure) of a substantially annular lens holder 21 to the other end of each of the four suspension wires 30, so that the optical head unit 20 has four base wires. It is movably supported via a suspension wire 30. In addition, the lens holder 21 side 4
Area 21 near each fixed end of the suspension wire 30 of the book
Also in b (in FIG. 1A, only the upper two positions are shown), the area 1 near each fixed end of the wire fixing block 12
Similar to 2a, a damping material (not shown) is provided.

In this actuator, the driving device is composed of a pair of fixed magnet portions 14 in the base portion 10, a focusing coil 23 and a pair of tracking coils 24 in the optical head portion 20. Four
Each of the suspension wires 30 of the book has elasticity and conductivity, and functions as a supporting member for the optical head unit 20 and also as a member for electrically connecting to the focusing coil 23 and the pair of tracking coils 24. To do. Then, a control voltage is applied to the focusing coil 23 and the pair of tracking coils 24, and the optical head portion 20 is driven in the focusing direction and the tracking direction by the magnetic flux action between these coils and the pair of fixed magnet portions 14. Adjust the focus and tracking of the objective lens 22.

The optical head actuator according to this embodiment further has the following structure.

In the lens holder 21 of the optical head unit 20,
At the portion facing the wire fixing block 12 (on the left side in the figure),
It has an inverted L-shaped movable piece 21c which is provided so as to extend from there to the wire fixing block 12 and moves together with the optical head portion 20. The movable piece 21c is the lens holder 2
Since it is a part of No. 1, it is possible to reduce the number of parts, reduce the weight, and reduce the number of assembly steps as compared with the case of using separate parts, and unnecessary vibration due to rattling of the connection relationship between multiple parts. It goes without saying that the occurrence of

Further, a concave portion 12b is formed on the main surface of the wire fixing block 12 so as to accommodate at least an end portion of the movable piece 21c. The recess 12b is sized to have a margin with respect to the moving range of the movable piece 21c, which is the same as the moving range of the optical head 20 (lens holder 21) in the focus direction and the tracking direction. Recess 1
2b further has a predetermined volume for accommodating a predetermined amount of damping material described later.

A damping material 40 for damping unnecessary vibration of the movable piece 21c is accommodated in the recess 12b. Damping material 40
For example, silicone gel is applied. As the silicone gel, there are, for example, one that gels when irradiated with ultraviolet rays, and one that gels when heated to a predetermined temperature. In this example, an ultraviolet gelling silicone gel was used. The damping material 40 made of silicone is used for the recess 12 by the following method.
It is provided in b. First, liquid silicone is injected into the recess 12b so that the recess 12b is, for example, almost full. Then, the lens holder 21 is moved in the recess 12b containing the liquid silicone so that the lens holder 21 is in the initial position in the focus direction, that is, the movable piece 21c is in the predetermined depth position. Piece 21
Insert c. Next, the liquid silicone in the recess 12b is irradiated with ultraviolet rays to form the damping material 40 made of gel silicone (silicon gel). With such a configuration, the vibration damping member 40 absorbs unnecessary vibration that occurs when the optical head unit 20 moves in the focus phrase and the tracking direction. In addition, it is preferable that the damping material provided in the above-mentioned fixed end vicinity region regions 12a and 21b be the same material.

Now, when the movable piece 21c is inserted into the recess 12b, since the silicone is in a liquid state, an excess amount of silicone, which is approximately the immersion volume of the movable piece 21c, overflows from the recess 12b. If the overflowed excess reaches, for example, the lens holder 20 or the like and gels in this state, it is not preferable because the vibration damping material will be formed in an undesired place. In addition, removing this causes an increase in the number of manufacturing steps. On the other hand, in the present invention, the excess silicone overflow is positively discharged and stored in a place where the operation of the actuator is not adversely affected. That is, in the optical head actuator according to the present embodiment, the wire fixing block 12 is formed adjacent to the recess 12b,
It has a preliminary recess 12c for accommodating an excess amount of the damping material 40 (silicone) overflowing from the recess 12b. Recess 12b
And the preliminary recess 12c between the wire fixing block 12
A convex portion lower than the main surface of the. This ridge defines a path 12d for the silicone. Therefore, when the movable piece 21c is inserted into the concave portion 12b in which the liquid silicone is contained, the excess silicone overflow is entirely accommodated in the preliminary concave portion 12c through the path 12d. After that, ultraviolet rays are applied to the inside of the concave portion 12b and the preliminary concave portion 12b.
By irradiating both the inside and the inside of c, the silicone in both the parts gels together and does not flow out from both parts thereafter.

The predetermined volume of the recess 12b mentioned above means the moving range of the movable piece 21c, the size and shape of the movable piece 21c in terms of fluid dynamics such as the cross-sectional area and shape of the immersed portion, and the movable piece 21c. The volume equal to the preferable volume of the damping material 40 calculated based on the frequency of unnecessary vibration, the viscosity of the damping material 40, and the like.

[0019]

The optical head actuator according to the present invention is provided in a portion of the optical head portion facing the wire fixing block so as to extend toward the wire fixing block, and a movable piece that moves together with the optical head portion. There is a recess formed in the wire fixing block so as to surround at least the end of the movable piece with a margin with respect to the moving range of the movable piece, and a damping material that is housed in the recess and suppresses the vibration of the movable piece. However, since the concave portion has a predetermined volume so as to accommodate a predetermined amount of damping material, it has excellent vibration damping characteristics. That is, it is possible not only to sufficiently suppress unnecessary vibration but also to quickly suppress vibration, and it does not hinder the normal operation of the optical head unit.

Further, it has a simple structure and is easy to manufacture.

[Brief description of drawings]

1A and 1B are views showing an optical head actuator according to an embodiment of the present invention, in which FIG. 1A is a top view and FIG. 1B is a vertical sectional view.

FIG. 2 is a plan view showing an optical head actuator according to a conventional example.

[Explanation of symbols]

 10 Base Part 11 Base 12 Wire Fixing Block 12a Fixed End Vicinity Region 12b Recess 12c Preliminary Recess 12d Path 13 Screw 14 Fixed Magnet 14a Magnet 14b Yoke 15 Cap 20 Optical Head 21 Lens Holder 21a Hole 21b Fixed End Vicinity 21c Movable One piece 22 Objective lens 23 Focusing coil 24 Tracking coil 30 Suspension wire 40 Damping material FC Focusing direction TR Tracking direction

Claims (3)

[Claims] 1. A base part, a plurality of elastic suspension wires each having one end fixed to a wire fixing block provided on the base part, and an objective lens, and the other end of each of the plurality of suspension wires. An optical head unit that is fixed and is movably supported by the base unit via the plurality of suspension wires, and is provided on the base unit and the optical head unit, and drives the optical head unit in the focus direction and the tracking direction. In an optical head actuator having a drive device, provided in a portion of the optical head portion facing the wire fixing block so as to extend from there to the wire fixing block,
A movable piece that moves together with the optical head portion, a recess formed in the wire fixing block so as to surround at least an end portion of the movable piece with a margin with respect to a moving range of the movable piece, and the recess is housed in the recess. An optical head actuator, comprising: a vibration damping material for damping the vibration of the movable piece; and the recess having a predetermined volume so as to accommodate a predetermined amount of the vibration damping material. 2. The optical head actuator according to claim 1, further comprising a preliminary concave portion formed adjacent to the concave portion on the wire fixing block to accommodate an excess amount of the vibration damping material overflowing from the concave portion. 3. The optical head according to claim 1, wherein the optical head section has a lens holder for holding the objective lens, and the movable piece is formed in an inverted L shape by a part of the lens holder. Head actuator.