JPH04205924A - Objective lens driving device for optical disk - Google Patents

Abstract

PURPOSE:To enhance the torsional rigidity in a rolling direction and to stabilize the writing and reading out operation of information to and from an optical disk by bridging and applying a vibration proof agent to the respective connecting parts of 4 sheets of leaf springs for focusing, a movable part and a junction plate. CONSTITUTION:The vibration proof agent 9 is applied on 4 sheets of the leaf springs 3A to 3D for focusing. This vibration proof agent 9 is further bridged and applied respectively in the connecting parts of the moving body 2 and the leaf springs 3A to 3D for focusing and the connecting parts of the junction plate 4 and the leaf springs 3A to 3D for focusing. The vibration proof agent 9 having the hardness higher than the hardness of a rubber-like adhesive material and the rigidity higher than this material is used. Then, the force to twist and incline the movable part 2 is generated when the magnetic force to move the movable part 2 in the focus direction and the track direction is applied but the torsional rigidity is enhanced by the vibration proof agent 9 and, therefore, the generation of a twist and inclination is obviated and the parallelism of the movable part 2 is assured. The writing and reading out of the information to and from the optical disk are stably executed in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an objective lens drive device for an optical disc, and more particularly to an objective lens drive device for an optical disc equipped with a four-point support mechanism using a focusing plate spring.

[Conventional technology]

Conventional examples are shown in FIGS. 6 to 8. Of these, in FIG. 6, the movable part 12 that holds the objective lens 11 has four focusing plate springs 13A and 1 arranged in parallel.
The focusing leaf springs 13A to 13D are supported at four points by 3B, 13C, and 13D, and the other ends of the focusing leaf springs 13A to 13D are fixed to the relay plate 14.

The relay plate 14 is a focusing leaf spring 13A~
The fixing portion 164 is connected to the fixing portion 164 via a trasoking temporary spring 15 whose surface is arranged in a direction perpendicular to the fixing portion 13D. Further, the focusing leaf springs 13A to 13D are fixed to concave grooves 17 provided in the movable portion 12 and the relay plate 14 with a rubber adhesive 18.

The objective lens 11 has focusing plate springs 13A to 13.
The four-point support provided by D makes it possible to move parallel to the optical axis direction (focus direction) of the lens. At the same time, this objective lens 1 is also movable in one direction (toward the trunk) perpendicular to the tracking plate spring 15, and the movable part 12 is attracted by a magnetic circuit (not shown) (coil, magnetoft) to perform focusing. and tracking control.

In this way, focusing and tracking can be performed using a single magnetic circuit, thereby reducing the size and weight of the device.

Figure 8 shows a focusing leaf spring 3 in addition to the configuration of Figure 6.
The case where anti-vibration agent 9 is applied on each of a, 3b, 3c and 3d is shown.

[Problems to be Solved by the Invention] However, in this conventional objective lens drive device, the focusing leaf springs 3A to 3D are supported only by the rubber-like anti-vibration adhesive 8, so the supporting force is weak. When the objective lens is moved in the track direction and the left and right coverage of the trunk coil is lost, a secondary resonance called rolling resonance occurs due to the rotation of the movable part.

[Object of the Invention] The present invention improves the disadvantages of the conventional example, and in particular, effectively suppresses the rolling motion of the movable body that holds the objective lens, and thereby improves the read/write operation of information on an optical disk. It is an object of the present invention to provide a stabilized objective lens drive device for an optical disc.

[Means to solve the problem]

The present invention includes a cube-shaped movable body that holds the objective lens in the center along the movable direction, and four mutually parallel focusing plate springs that support this movable body at four points via a rubber adhesive. and a tracking leaf spring that connects ends of the four focusing leaf springs located on the side opposite to the movable body to a fixed support part via a relay support plate. In 4 above,
A vibration damping agent is applied to each of the focusing leaf springs, and the vibration damping agent is applied to the connecting portion between the movable body and the focusing leaf spring and the connecting portion between the relay plate and the focusing leaf spring, respectively. The structure is such that it is applied as a bridge. This aims to achieve the above-mentioned purpose.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

In the embodiment shown in FIGS. 1 to 5, the objective lens I
a cube-shaped movable body 2 that holds the movable body 2 in the center along the movable direction; four mutually parallel focusing leaf springs 3A that support the movable body 2 at four points via a rubber adhesive 8;
3B, 3C, 3D, and the ends of the four focusing leaf springs 3A to 3D located on the opposite side of the movable body 2 are connected to the fixed support part 6 via the relay support plate 4 for tracking. A leaf spring 5 is provided.

Among them, a vibration damping agent 9 is applied to the four focusing leaf springs 3A to 3D, and the vibration damping agent 9 is also applied to the connecting portions between the movable body 2 and the focusing leaf springs 3A to 3D, and the above-mentioned Relay support plate 4 and focusing leaf spring 3
It is applied as a bridge to the connection parts A to 3D, respectively.

As the vibration damping agent 9, a material having higher hardness and greater rigidity than the rubber-like adhesive material 8 described above is used.

To explain this in more detail, in FIG. 1, the objective lens 1
The movable part 2 holding the is supported at four points by four focusing leaf springs 3A, 3B, 3C, and 3D arranged in parallel.
The other end of D is fixed to the relay plate 4. The relay plate 4 includes focusing leaf springs 3A, 3B, 3C, 3D.
It is connected to a fixed part 6 via a tracking leaf spring 5 whose surface is arranged perpendicular to the . Further, the focusing leaf springs 3A, 3B, 3C, and 3D are fixed to concave grooves 7 provided in the movable portion 2 and the relay plate 4 with a rubber adhesive 8.

The feature of this embodiment is that a vibration damping agent 9 is applied on the four focusing leaf springs 3A, 3B, 3C, and 3D, and as shown in FIG.
A vibration damping agent 9 is applied to each connecting portion 10 between 3C and 3D, the movable portion 2, and the relay plate 4 as a bridge.

Therefore, when one magnetic circuit applies a magnetic force that moves the movable part 2 in the focus direction and the track direction, the forces in both directions are combined and act on the movable part 2, causing the movable part 2 to twist or tilt. Although a force is generated, the anti-vibration agent 9
By bridging the movable part 2 to each connecting part 10, the torsional rigidity in the rolling direction R shown in FIG. This anti-vibration agent 9 is a rubber-like adhesive 8
It has higher hardness and rigidity, and has a damper effect in the focus direction.

〔Effect of the invention〕

As described above, according to the present invention, the vibration damping agent is bridged between the four mutually parallel focusing leaf springs that support the movable part that holds the objective lens at four points, the movable part, and the relay plate. Since the structure is such that the torsional rigidity in the rolling direction is increased, there is no twisting or inclination, and only linear movement occurs, suppressing secondary resonance. It is possible to provide an unprecedented and excellent objective lens drive device for an optical disc that can stably write and output information.

[Brief explanation of the drawing]

FIG. 1 is a front view showing one embodiment of the present invention, and FIG. 2 is a front view showing one embodiment of the present invention.
3 is a detailed explanatory diagram showing part A of FIG. 1,
4 is a sectional view taken along line IV-IV in FIG. 3, FIG. 5 is a right side view of FIG. 1, FIG. 6 is a front view of the conventional example, and FIG. 7 is a cross-sectional view of FIG. A sectional view taken along the line -■, and FIG. 8 a front view showing another conventional example. 1...Objective lens, 2...Movable part, 3
A~3D・・・Focusing leaf spring, 4...
... Relay plate, 5 ... Tracking plate spring, 6 ... Fixed part, 7 ... Concave groove, 8
...Rubber-like adhesive, 9...Vibration damping agent,
10...Connection part. Applicant Japan Electric Co., Ltd. Agent Patent Attorney Isamu Takahashi Fig. 1 M, 3B, 3C, 3D 2 leaf springs for focuserongs Fig. 2 3A, 3c Fig. C Fig. 7 Fig. 8 Book

Claims (2)

[Claims] (1) A cube-shaped movable body that holds the objective lens in the center along the movable direction, and four mutually parallel focusing plate springs that support this movable body at four points via a rubber adhesive. and a tracking leaf spring that connects ends of the four focusing leaf springs located on the side opposite to the movable body to a fixed support part via a relay support plate. In addition to applying a vibration damping agent to the four focusing leaf springs, the vibration damping agent is further applied to the connecting portion between the movable body and the focusing leaf spring and the connecting portion between the relay plate and the focusing leaf spring. 1. An objective lens drive device for an optical disc, characterized in that the connecting portions are each coated as a bridge. (2) The objective lens drive device for an optical disc according to claim 1, wherein the vibration damping agent is made of a material having higher hardness and greater rigidity than the rubber adhesive.