JPH02230520A - Objective lens supporter - Google Patents

Abstract

PURPOSE:To obtain an objective lens supporting device simplified and with few amount of dispersion and having satisfactory damping effect by employing structure in which a metallic thin plate, soft resin, hard resin, and the soft resin are laminated as an elastic supporting body to correct the change of an objective lens. CONSTITUTION:When a coil is driven by supplying a current, a tracking elastic supporting device generates deflection by receiving a bending moment, and a shearing force is applied between the metallic thin plate 1 and the hard resin 3 in the center of the device, then, distortion is generated at the hard resin 3. Meanwhile, since the hard resin 3 is stuck with a metallic plate 4 via a outside soft resin 2, it is fixed with an appropriate degree of freedom, consequently, appropriate rigidity can be maintained. An effective damping effect can be obtained by the deflection due to the shearing force of the soft resin 2, however, since remarkable change in hardness due to a temperature can be seen in the soft resin 2 in many cases, it is desirable to use only a few quantity of soft resin 2. Effective damping effect and spring constant can be obtained by minimizing the quantity of the soft resin 2 by performing the optimization of the thickness of the hard resin 3. Also, the damping effect is applied not only on the deflected part of the metallic thin plate 1 but on the function of the soft resin 2 effectively extending over the whole of a part to be stuck.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an objective lens support device in which an objective lens is movably supported by an elastic support device in order to correct displacement of the objective lens with respect to a recording medium. be.

[Conventional technology]

Generally, an objective lens support device of an optical disk device has an actuator structure to enable fine adjustment of the optical axis. This actuator enables fine adjustment by a combination of a coil, a permanent magnet, and an elastic support.

Conventionally, in this type of objective lens support device, the elastic support body is composed of a thin plate spring, and is further provided with butyl rubber, silicone rubber, etc. in order to absorb vibrations.

FIG. 2 is an exploded perspective view of a conventional objective I men's support device, and FIG. 3 is a partially enlarged view of the L/racking direction elastic support device. The movable part 24 has a tracking coil 2 fixed to a fixed part 23 via an elastic support 22.
When a current is passed through 8, the elastic support body is deflected in the direction of the arrow depending on its polarity, thereby moving the objective lens 26. In this case, ideally the objective lens 26 should be set at point 25 as a fulcrum.
makes a circular motion. However, since the objective lens 26 is also displaced in the focus direction 27, a torsional force is generated due to a shift between the point of application of the generated force and the point of generation of the reaction force by the elastic support. Furthermore, since the elastic support body has a finite width, the movable part and the fixed part are also displaced in parallel directions.

This causes harmful parasitic resonance, so damping material is added to stabilize it.

[Problem to be solved by the invention]

In the conventional support mechanism mentioned above, since the elastic support, movable part, fixed part, and damping material are assembled separately, there are many variations in assembly, making it difficult to achieve stable performance. In order to achieve this, it is necessary to reduce the distance between the fixed part and the movable part, but this has the disadvantage that it becomes difficult to apply the damping material.

[Means to solve the problem]

The objective lens support device of the present invention is an objective lens support device in which a thin metal plate is disposed at the center of the elastic support device in the tracking direction. The feature is that soft resin, hard resin, and soft resin are laminated on both sides in this order, and a two-part metal plate is glued to the outermost side.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

/ Figure V shows a tracking elastic support device according to an embodiment of the present invention. A thin metal plate 1, a soft resin 2, a hard resin 3, a soft resin 2, and a metal plate 4 are laminated and assembled as shown in FIG. The thin metal plate 1 is suitably made of spring stainless steel or the like with a diameter of about 20 to 50 microns, and the soft resin has a thickness of about 5 to 50 microns and also serves as an adhesive in this case. The hard resin used is polyimide film, polyester film, etc. The outermost metal plate is used to create a rigid structure, and only the gap in the center of the division acts as an elastic body. It is preferable to make the gap as narrow as possible in order to make the elastic body into an ideal hinge. In the embodiment of the present invention, photoetching is performed to reduce the thickness from 2mm to 0.0mm. It is made between 5 mm.

The elastic support device is engaged with and fixed to the fixing portion 6 and the intermediate support body 5, respectively, thereby forming an objective lens support device. A coil and an objective lens are engaged with the movable part via a focusing elastic support device, and the coil is driven by receiving magnetic force between the yoke and the permanent magnet.

In the tracking elastic support device, the primary resonance point is set at approximately 30H to 50H.

Next, the operating principle of this embodiment will be explained.

When a current is supplied to the coil and the coil is driven, the tracking elastic support device generates deflection due to the bending moment. A shearing force acts between the central thin metal plate 1 and the hard resin 3, causing distortion in the hard resin 3. On the other hand, since the hard resin 3 is bonded to the metal plate 4 via the outer soft resin 2, it is fixed with an appropriate degree of freedom. Therefore, appropriate rigidity can be maintained. The deflection of the soft resin 2 due to the shearing force produces an effective vibration damping effect, and in general, the soft resin 2 often undergoes significant changes in altitude etc. depending on the temperature, so the amount of the soft resin 2 used is as small as possible. is preferable. By optimizing the thickness of the hard resin 3, it is possible to minimize the amount of the soft resin 2 and obtain an effective vibration damping effect and spring constant. In addition, in the case of this structure, the damping effect is not limited only to the bent portion of the thin metal plate 1, but also has the effect that the soft resin 2 of the entire bonded portion acts effectively.

〔Effect of the invention〕

As explained above, the present invention has a structure in which a thin metal plate, a soft resin, a hard resin, and a soft resin are laminated as an elastic support material to correct changes in the objective lens relative to the recording medium. This has the effect of providing an objective lens support device that has a vibration damping effect.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a portion according to the present invention, FIG. 2 is an exploded perspective view of a conventional objective lens support device, and FIG. 3 is a partially enlarged view of an elastic support portion. 1... Metal thin plate, 2... Soft resin, 3
...Hard resin, 4...Metal plate, 5...
...Intermediate support, 6 fixed parts. Agent Patent Attorney Oto Uchihara

Claims (1)

[Claims] an objective lens that illuminates the optical disc medium with a light spot;
An objective lens support device including a coil fixed to the objective lens, a permanent magnet that provides lines of magnetic force to the coil, and an elastic support member that provides a reaction force against the driving force generated by the coil and the permanent magnet, An objective lens characterized in that the structure of the elastic support mechanism is such that a thin metal plate is placed in the center, soft resin, hard resin, and soft resin are laminated in this order on both sides, and two metal plates are bonded to the outermost sides. Support device.