JPH04188438A - Objective-lens supporing device for optical head - Google Patents

Abstract

PURPOSE:To make it possible to write and read data stably by forming focusing plate springs which support a holding part of an objective lens in an approximately H shape by using two strip-shaped parts and a bridging part for linking the strip- shaped parts. CONSTITUTION:This apparatus is composed of an objective lens 1, a holding part 2 for the objective lens 2, a pair of upper and lower plate springs 7a and 7b for rotatably supporting the holding part 2 in the direction of an optical axis, a relay member 4 for fixing one end of each plate spring and a tracking plate spring 5 one end of which is fixed to the relay member 4 and the other end of which is fixed to a base 6. The focusing plate springs 7a and 7b have the plate surfaces crossing the optical axis at right angles. Both springs are arranged in parallel to each other. One end of a strip-shaped part 7c is fixed to the holding part 2, and the other end is fixed to the relay member 4. The two parallel strip-shaped parts 7c and one bridging part 7d for linking the intermediate parts of the strip-shaped parts 7c are provided. The strip-shaped parts 7c and the bridging part are formed in an approximately H shape. Thus, even if driving is performed in the direction of the optical axis and in the direction which is perpendicular to the direction of the optical axis, mutual interference is not generated and the stable writing and the reading of the data can be performed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical disk device that optically writes information on a disk-shaped medium by irradiating a light beam onto the medium or optically reads written information. In particular, the present invention relates to an objective lens support device for an optical head used for writing and reading.

[Prior Art] Conventionally, the objective lens support device of this type of optical head has a third
The devices shown in Figures (a) and (b) are known.

FIG. 3(a) is a plan view of the objective lens support device, and FIG. 3(b) is a front view thereof.

In the figure, an objective lens 1 is attached to a holder 2, which is supported by a relay member 4 via a focusing plate spring 3, and which is supported by a base 6 via a tracking plate spring 5. There is.

The focusing leaf spring 3 is composed of four belt-shaped leaf springs, including two parallel upper springs 3a and 3b and lower leaf springs 3c and 3d parallel to the leaf springs 3a and 3b. There is. These four wooden leaf springs 38 to 3d are all arranged so as to have a plate surface perpendicular to the optical axis of the objective lens 1, and are supported so that the holding part 2 can move in the optical axis direction. The tracking leaf spring 5 is composed of a single leaf spring, arranged so that its plate surface is parallel to the optical axis, and holds the holding part 2 in a direction perpendicular to the optical axis (with respect to an information track of an optical disc (not shown)). It is supported so as to be movable in orthogonal directions, i.e., in the radial direction.

In this objective lens support device, when a 1ifB driving force is applied to the holding part 2 by a coil and a magnetic circuit, for example, the holding part 2 is driven in the optical axis direction by the deformation of the focusing plate spring 3, and the light on the optical disk is Spot focusing is achieved, and the holding part 2 is connected to the tracking plate spring 5.
Due to this deformation, the focusing leaf spring 3 is driven in a direction perpendicular to the optical axis, and the optical spot on the optical disk is tracked.

[Problems to be Solved by the Invention] However, in the conventional objective lens support arrangement, each of the four focusing leaf springs can be deformed independently, and the direction of elastic deformation of the leaf springs is not constant. Furthermore, since the movement in the optical axis direction is also controlled in the tracking direction, mutual interference is likely to occur with the movement of the holding section in the tracking direction. Therefore, the objective lens is tilted or rotated, and there is a drawback that stable information writing and reading cannot be performed.

SUMMARY OF THE INVENTION An object of the present invention is to provide an objective lens support device that can stably write and read information.

[Means for Solving the Problems] The objective lens support device for an optical head of the present invention has one end fixed to a holder that holds the objective lens, and supports the holder so that it can move in the optical axis direction. a pair of focusing plate springs parallel to each other; a relay member fixing the other end of the plate spring; one end fixed to the relay member and the other end fixed to the base member; An objective lens support device for an optical head, comprising a tracking plate spring that supports the holding part so as to be movable in a direction perpendicular to the optical axis via the plate spring, Each is composed of two mutually parallel belt-shaped parts that connect the holding part and the relay part, and a bridge part that connects the middle part of the belt-shaped parts.

[Example] Next, an example of the present invention will be described in detail with reference to the drawings.

1 and 2 show one embodiment of the present invention, and FIG. 1(a) is a plan view of the objective lens support device;
FIG. 1(B) is a front view thereof, FIG. 1(C) is a side view thereof, and FIG. 2 is a plan view of the focusing leaf spring. In addition,
Components in the drawings having the same configuration as the conventional device will be described with the same reference numerals.

The objective lens support device according to the present invention includes an objective lens 1,
A holding part 2 of the objective lens 1, a pair of upper and lower leaf springs 7a and 7b that support the holding part 2 movably in the optical axis direction,
Relay member 4 that fixes one and one of these leaf springs 7a and 7b
The tracking plate spring 5 has one end fixed to the relay member 4 and the other end fixed to the base 6.

The two focusing plate springs 7a and 7b have plate surfaces perpendicular to the optical axis, and are arranged parallel to each other.
As shown in FIG. 2, two mutually parallel belt-shaped parts 7c are fixed at one end to the holding part 2 and the other end to the relay member 4, and one bridge part connects the middle part of the belt-shaped parts 7c. 7d, and is formed into a substantially H-shape.

Now, when the driving force for focusing is applied to the holding part 2,
The upper and lower leaf springs 7a and 7b are deformed in a direction perpendicular to their plate surfaces to drive the holding portion 2 in the optical axis direction. At this time, the bridging portions 7d of the focusing leaf springs 7a and 7b have improved rigidity in the torsional direction shown by arrow A in FIG. 1(c), so the upper and lower leaf springs 7a and 7b are Since rotation can be prevented, movement in the focus direction can be accurately controlled, and interference in the tracking direction can be prevented.

Next, when a driving force for tracking is applied to the holding part 2,
The tracking leaf spring 5 deforms in a direction perpendicular to the optical axis, and drives the holding part 2 in the tracking direction. Due to this movement in the tracking direction, the focusing leaf spring 7a
and 7b have high rigidity against torsion due to the presence of the bridge portion 7d, and therefore are not subject to interference in the rotational direction of arrow A and the focusing direction.

[Effects of the Invention] As explained above, the present invention includes two belt-shaped parts that fix the focusing plate spring supporting the holding part of the objective lens at both ends to the holding part and the relay member, respectively; Since this band-shaped part is formed into a substantially H-shape with the bridge part that connects each other, the rigidity in the torsional direction that occurs when the holding part is driven in the focusing direction or tracking direction is large, and the holding part can move linearly. This suppresses rotational movement. Therefore, even if the drive is performed in the direction of the optical axis (focus direction) and the direction perpendicular to the optical axis (tracking direction), there will be no interference with each other, and sufficient responsiveness is achieved, allowing stable information writing and reading. It has the effect of allowing you to do this.

[Brief explanation of the drawing]

FIG. 1 shows an objective lens support device in an embodiment of the present invention, (a) is a plan view, (b) is a front view, (c) is a side view, and FIG. 2 is a focusing device shown in an embodiment of the present invention. FIG. 3 shows a conventional objective lens support device, with FIG. 3(a) being a plan view and FIG. 3(b) being a front view. l... Objective lens, 2... Holding part, 3... Leaf spring for focusing, 4... Relay member, 5... Leaf spring for tracking, 6... Pace, 7... Focusing leaf spring.

Claims (1)

[Claims] A pair of mutually parallel focusing leaf springs, one end of which is fixed to a holder that holds an objective lens and supports the holder so that it can move in the optical axis direction, and the other end of the leaf spring. A relay member to be fixed; one end portion fixed to the relay member and the other end portion fixed to a base member, and the holding portion supported so as to be movable in a direction perpendicular to the optical axis via the leaf spring. an objective lens support device for an optical head, comprising one tracking leaf spring, each of the focusing leaf springs having two parallel belt-like parts connecting the holding part and the relay part; 1. An objective lens support device for an optical head, comprising: and a bridge portion connecting intermediate portions of the band-shaped portions.