JPS60263347A - Objective lens driver - Google Patents

Abstract

PURPOSE:To improve the mass productivity and performance of objective lens drivers by securing such a constitution where four supporters for an object to be driven are formed in parallel to each other by winding a metallic fine wires double and spirally. CONSTITUTION:A focusing coil 6 and a tracking coil 7 are attached around a bobbin 5 attached with an objective lens 4, and both ends of four supporters 1 are attached to fixed frames 8 and 3 respectively. The supporter 1 is formed by winding a metallic fine wire double and spirally. When a connection pin 9 is energized, a part to be driven including the lens 4, the bobbin 5 and coils 6 and 7 can be driven in both focusing and tracking directions x and y. The supporter 1 has high resistance to its deformation and can be assembled with no tilt of the lens 4. Thus the ideal damping is possible with a wide range of working temperatures and the highly stable performance.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention relates to an objective lens driving device that drives an objective lens for reading information optically recorded on a recording medium in two directions: in the direction of the recording medium and in two directions parallel to the recording medium. Regarding.

[Background of the invention: Two companies]

As a conventional device of this kind, Utility Model Application No. 58-16573
As described in Publication No. 7, in order to vibrate in two directions, the support part is constituted by a leaf spring, so the 1K
In the vicinity of Hz, a phenomenon in which the operations in two directions interfere with each other may occur due to the natural resonance of the leaf spring, which may impede accurate servo response performance.

[Purpose of the invention]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an objective lens driving device for an optical information reproducing device that eliminates the above-mentioned drawbacks, has excellent mass productivity, and has high performance.

[Summary of the invention]

The present invention provides a support in which a metal wire is closely wound around a member having a viscoelastic material such as rubber attached to a metal core material in a cylindrical shape, or a coil spring tightly wound.
A support body for an objective lens driving device is obtained which is made of a double tightly wound wire.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in detail using the drawings.

FIG. 1 is a partially sectional perspective view of an objective lens driving device using a support 1 according to an embodiment of the present invention. The objective lens 4 is attached to a barrel 5, and a focusing coil 6 and tracking coils 7a and 7b are wound around the barrel 5. Further, first support fixing frames 8a to 8b are attached to the pobbin 5, and one ends of the supports 1a to 1d are attached to each of the first fixing frames. The other ends of the supports 1a to 1d are attached to the second fixed frame 3. In this embodiment, the support body 1 uses four coil springs that are tightly wound once and double tightly wound as strands. Inside the supports 18 to 1d, winding ends of coils for supplying current to the focusing and tracking coils are interposed. The winding ends are connected to external connection pins 98 to 9d by a pattern drawn on the second fixing frame 3, soldering, etc.

Magnetic circuits 118-llb are attached to the base 10 so that the focusing coil 6 and tracking coils 7a-7b are interposed in the air gap magnetic field. Therefore, when a current is supplied to the connection pins 98 to 9d, the driven parts including the objective lens 4, the pin 5, the focusing coil 6, and the tracking coils 7a to 7b are driven in the focusing direction (X) and the tracking direction (y). It becomes possible.

Figures 2 and 3 show a part of the support according to the invention.

FIG. Figure 2 shows a double coil spring structure in which thin metal wires are tightly wound and then tightly wound again as strands.

FIG. 3 shows a member in which a thin metal wire 14 is tightly wound around a member in which a viscoelastic body 13 such as rubber is adhered to a metal core 12 in a cylindrical shape. The metal core material 12 is a lead wire for supplying current to a driven part.

Figure 2 shows that when the driven part is vibrating, the coils are in close contact with each other, so a shift occurs in the -th and second turns of the coil, and vibration energy is converted into thermal energy. The effect was to dampen the sharpness of the resonance (QO).

In the example shown in Figure 3, the sharpness of the resonance could be damped more than the conventional product due to the damping effect of the viscoelastic material along with the effect of the misalignment of the coil.

FIG. 4 shows the vicinity of the lowest resonance frequency 0) of the amplitude frequency characteristic of the driven body of the objective lens driving device when the structure is used as a parameter for supports having almost the same shape.

In Fig. 4, A is the double coil spring-shaped support of the present invention, B is the support of the present invention in which fine metal wire is closely wound around the viscoelastic body, and C is the conventional product. be. In FIG. 4, the frequency characteristic of the embodiment according to the present invention is less sharp than that of the conventional product, about 10 dB.
I was able to make it smaller.

〔Effect of the invention〕

According to the present invention, by using four double-structured close-contact coil springs and a support body made of a fine metal wire tightly wound around a viscoelastic body, the support body is strong against post-manufacturing shapes, and During assembly, the lens can be installed without tilting. Even if the spring material is made of a material with low internal loss such as metal, it is now possible to obtain a material with ideal damping and good linearity as the support. The operating temperature range for materials such as metals is -409C to 1
Even at 10°C, the spring properties did not change at all, and stability was significantly superior to that of viscoelastic materials such as rubber.

The present invention relates to a support device, and the drive structure is not limited to that shown in the embodiments of the present invention.

[Brief explanation of drawings]

1 is a partially sectional perspective view of an embodiment of the present invention, FIG. 2 is an enlarged perspective view of a part of the support shown in FIG. 1, FIG. 3 is an enlarged perspective view of another example of the support, and FIG. The figure is a characteristic diagram. 1... Support body 2... Driven body 4... Objective lens agent Akio Takahashi ¥2m 1 No. 30 No. 40

Claims (1)

[Claims] 1. A driven body equipped with a plurality of coils for driving an objective lens for reading information optically recorded on a recording medium in two directions: in the direction of the recording medium and in two directions parallel to the recording medium. In an objective lens drive device that drives a lens in each direction by a corresponding electric signal, the support body that supports the driven body has four coils parallel to each other, each of which is made of a thin metal wire tightly wound in a spiral shape. An objective lens driving device characterized by having a double helical structure in which a spring is tightly wound in a spiral shape once again as a wire. 2. The objective lens drive device according to claim 1, wherein the support body is a cylindrical viscoelastic material tightly wound with a thin metal wire.