JP2910226B2 - Focus actuator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a focus actuator in an optical memory device.

[Prior Art] As shown in FIG. 5, a conventional focus actuator has an objective lens 501, a coil 502, a parallel leaf spring 503, and a base 504 arranged in a horizontal direction, and an electromagnetic force between a coil and a magnetic circuit fixed outside. The driving force is obtained by the action, and the focusing operation is performed by the deformation of the elastic body.

[Problems to be Solved by the Invention] However, in the prior art, the base 504 and the prism 5
The chassis 506 connecting the 05 was required, and the whole became longer, the weight of the movable part increased, and the access time was longer. Alternatively, power consumption has increased.

[Means for Solving the Problems] A focus actuator of the present invention focuses on an optical storage medium, has at least an objective lens, a coil, an elastic body, and a base, and fixes the coil to the objective lens. At the same time, the coil and the base are connected by an elastic body, and the objective lens, the coil, the elastic body, and the base are arranged in the direction perpendicular to the optical storage medium in this order, and the coil is rectangular, and the elastic body is The prism is formed by a spring element connected to each side of the rectangle, and has a prism that bends a light beam traveling parallel to the storage medium surface toward the objective lens.The base has a hole through which the light beam passes, and the prism has It is characterized by being directly adhered and fixed to the upper surface on the objective lens side.

[Operation] As shown in FIG. 1, the objective lens 101 and the coil 102 are
It is fixed to the base 104 via 103. A driving force is obtained by an electromagnetic action between a magnetic circuit fixed to the outside and the coil 102, and the spring 103 is expanded and contracted in the vertical direction to perform a focus operation.

Hole 1 large enough for light beam to pass through base 104
05 is opened and directly adhered to the prism 106.

FIG. 2 is a view from above, in which the objective lens 201 is fixed to a rectangular coiled coil 202, and four spring elements 203, 204, 205, 206 corresponding to each side of the rectangular coil.
Is held by With such a configuration, the inclination of the objective lens can be minimized.

FIG. 3 shows an embodiment of the present invention.

The objective lens 301 is adhered to the bobbin 302,
A coil 303 is fixed to 302. The bobbin 302 has a spring 304 having a constricted portion and a base 305 integrally formed by a plastic mold. Base 305 is prism 30
Adhered to 6.

Magnetic circuit including magnet 307 and yoke 308 and coil 303
A vertical force acts on the coil due to the electromagnetic effect of the object, deforming the spring 304 and moving the objective lens 301 up and down.

12 constrictions of the spring 304 are deformed, and the objective lens 301
Is moved up and down in parallel.

Reference numeral 309 denotes a linear motor coil for moving the entire focus actuator. In FIG. 3, the magnetic circuit for the linear motor is omitted.

In this embodiment, the yoke 307, the spring 304, the base 305, and the holder 310 of the coil for the linear motor are manufactured by integral molding of plastic.

FIG. 4 shows another embodiment of the present invention.
This is an example in which one leaf spring 401 is used. Hole 40 in base 402
There are three, which are glued to the prism 404.

[Effects of the Invention] As described above, according to the present invention, a chassis for connecting a base and a prism, which is a conventionally required focus actuator fixing portion, is not required, and an optical component can be used as a structure. Weight can be reduced,
High-speed access and low power consumption have become possible.

In addition, the inclination of the objective lens can be prevented from being generated by the configuration of the spring of the present invention.

[Brief description of the drawings]

 FIG. 1 is a sectional view of the configuration of the present invention. FIG. 2 is a plan view of the configuration of the present invention. FIG. 3 is a perspective view of an embodiment of the present invention. FIG. 4 is a cross-sectional view of another embodiment of the present invention. 101, 201, 301, 501 ... objective lenses 102, 202, 303, 502 ... coils 103, 304 ... springs 104, 305, 402 ... bases 105, 403 ... holes 106, 306, 404, 505 ... Prism 107 Optical storage media 203, 204, 205, 206 Spring element 302 Bobbin 307 Magnet 308 Yoke 309 Linear motor coil 310 Holder 401 Plate spring 503 Parallel leaf spring 504 …… Base 506 …… Chassis

Claims (1)

(57) [Claims] 1. A focus actuator for focusing on an optical storage medium, comprising: at least an objective lens, a coil, an elastic body, and a base, wherein the coil is fixed to the objective lens, and the coil and the base are connected to each other. The objective lens and the coil, the elastic body, and the base are arranged in this order in a direction perpendicular to the optical storage medium surface, and the coil is rectangular, and the elastic body is the coil A prism that bends a light beam traveling parallel to the storage medium surface toward the objective lens, and the base has a hole through which the light beam passes. And a focus actuator directly adhered and fixed to the upper surface of the prism on the objective lens side.