JPH10134384A - Optical system supporting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out the rapid and exact assembly work for a supporting device by providing the system with a contact part where a planer member extends in a second direction nearly perpendicularly to a first direction and bringing the contact member into contact with a fixing member in a first direction. SOLUTION: A spring 6 formed by etching a metal, such as beryllium copper, having about 0.1mm thickness is positioned by fitting its one end 6j into a hollow groove 2b formed in a spring fixing part 2a disposed at the X-direction end of the holding member 2 and is fixed by an adhesive. The adhesive is injected via the end hole 6k of the spring 6 so as to be penetrated between the spring 6 and the spring fixing part 2a. The positioning in the direction Y of the spring 6 is executed by pressing the spring to the end face of a projecting part 6i formed at the end. Since the positioning of the spring 6 may be executed in such a manner, the easy and exact work may be carried out without using a positioning jig.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an optical system supporting device used for an optical information reading apparatus for reproducing information by projecting a light spot on a disc-shaped information recording medium, for example.

[0002]

2. Description of the Related Art When an information recording medium is irradiated with a light spot, a focusing mechanism for focusing on a recording surface is required.

Therefore, in order to move the objective lens at least in the focusing direction, the holding member holding the objective lens can be moved with respect to the fixing member by a plate-like member including an elongated portion and made of metal. An optical system supporting device designed to support the optical system in a suitable state is disclosed in, for example,
No. 259842 discloses in FIG.

In the apparatus disclosed in this publication, a holding member 2 holding an objective lens 1 is supported by a supporting member 6 on a base 13 which is a fixed member so as to be movable.

[0005]

However, in the configuration disclosed in the above publication, the accurate position of the support member 6 in the extending direction of the support member 6 with respect to the base 13 (the horizontal direction in FIG. 3 of the publication) can be quickly determined. There are drawbacks that do not appear.

An object of the present invention is to provide an apparatus which solves the above-mentioned disadvantages.

[0007]

An optical system supporting apparatus according to the present invention includes a holding member for holding an optical element, which includes a portion extending in an elongated shape at least in a first direction with respect to a fixing member and is made of metal. An optical system supporting device adapted to be movably supported by a plate-shaped member, wherein the plate-shaped member includes a contact portion extending in a second direction substantially perpendicular to the first direction; The contact portion is in contact with the fixing member in a first direction.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a first embodiment of the present invention. The four tracking coils 5 are provided on the tangential side of the holding member 2 on which the objective lens 1 is fixed and the focusing coil 4 is wound around the outer periphery of the side so as to be adjacent to the focusing coil 4.
Are fixed so that the winding axis is parallel to the tangential direction. A semi-circular concave groove 8a is formed in the direction of the optical path in the center of the base 8 formed by pressing an aluminum plate, and the base 8 on both sides of the concave groove 8a is opposed to the groove 8a in a direction orthogonal to the concave groove 8a. Two yokes 9 having bent yokes 9a and 9b are provided in the Y direction.

The yoke 9b is located at the opening 3 of the holding member 2. Inside the yoke 9a, a magnet 10 and two magnets 11 on both sides with the magnet 10 interposed therebetween, for a total of 3
The individual parts are fixed with their polarities reversed.

A spring 6 for supporting the holding member 2 so as to be movable in the focusing direction and the tracking direction is provided by fixing both ends to a fixing member 7 provided on the base 8 and the holding member 2. The spring 6 has a butyl rubber damper 12.
It is covered with. FIG. 3 shows a place where the spring 6 is fixed to the holding member 2. A spring 6 formed by etching a metal such as beryllium copper having a thickness of about 0.1 mm is fitted with one end 6j into a groove 2b formed in a spring fixing portion 2a provided at an end in the X direction of the holding member 2. And fix with an adhesive. The adhesive is injected through a hole 6k formed at the end of the spring 6, so as to be infiltrated between the spring 6 and the spring fixing portion 2a. The positioning of the spring 6 in the Y direction is performed by connecting the end face of the projection 6i formed at the end to the spring fixing section 2a.
This is done by abutting the end face of. Since the spring 6 can be positioned in this manner, simple and accurate work can be performed without using a positioning jig. Further, a V-shaped notch 6h is formed at the end, and the focusing coil 4 and the terminal 13 of the tracking coil 5 are temporarily held and soldered. Therefore, workability of temporary holding and soldering is good.

As shown in FIG. 2, the other end 6e of the spring 6 is connected to a spring fixing portion 7a provided at an end in the X direction of the fixing portion 7 in the same manner as described above ("same as above" Projection 6i
And the spring fixing portion 2a). still,
6d is a protrusion for positioning in the Y direction, and 6f is a hole for injecting an adhesive. The other end 6e further includes a projection 6g.
Is formed and soldered to the land of the printed circuit board to supply power to the focusing coil 4 and the tracking coil 5 via the spring 6.

Between the two ends 6e and 6f of the spring 6, there are tangential parallel portions 6a and 6c parallel to the Y direction continuous with the both ends, and a portion 6b bent between the 6a and 6c so as to approach the optical axis. have. A spring 6 on the opposite side of the objective lens 1 is also provided correspondingly, and the distance between the springs 6 in the X direction on both sides of the objective lens 1 is made shorter than the distance of other parts.

That is, the spring portion near the objective lens 1 is closest to the objective lens 1 as compared with the other spring portions. Although two springs 6 are provided in the Z direction as shown in FIG. 1, the lower spring is formed and provided in the same manner, and the holding member 2 is held by these four springs 6. It can be moved in the X and Z directions. With this configuration, the width of the optical system support device in the X direction can be reduced. Furthermore, a large space near the objective lens 1 can be obtained, and a spindle motor 13 having a large diameter can be used. A movement sensor in the X direction of the holding member 2 can be provided on the opposite side of the optical system supporting device. it can. Also, as in the present embodiment, the holding member 2 is narrowed between the springs 6 on both sides of the objective lens 1 as compared with the fixed member 7 side. Rigidity can be increased.

Next, X of the portions 6a, 6b and 6c of the spring 6
The widths in the direction are represented by ta, tb, and tc, respectively, and the relationship among them is represented by ta = tc <tb. For example, tc is 0.3 m
m and tb are 0.5 mm. The thickness in the Z direction is the same in each part. By doing so, the rigidity of the portion 6b is increased, and the rigidity of the holding member 2 against rotation around the X axis and the Y axis and the rigidity in the Y direction can be increased. Therefore, the inclination of the optical axis of the objective lens 1 can be prevented and the resonance frequency can be increased.

According to the plan view shown in FIG. 2, the state of the magnetic flux acting on the tracking coil 5 and the focusing coil 4 is clear. The magnetic flux generated from the magnet 10 is applied to two opposing sides 5 a and 5 b of the tracking coil 5.
Of the focusing coil 4 is orthogonally directed toward the yoke 9b.

On the other hand, the other side 5 of the tracking coil 5
The magnetic flux from the magnet 11 acts on b in a direction opposite to the magnetic flux acting on 5a. Therefore, when required currents are respectively supplied to the focusing coil 4 and the tracking coil 5, the focusing control and the tracking control of the light beam from the objective lens 1 can be performed.

In this embodiment, since the flat tracking coil 5 is fixed to the tangential side of the holding member 2, the dimensions of the optical system driving device in the tangential direction and the tracking direction can be reduced, and the size can be reduced. .
Further, the magnetic flux acting on the focusing coil 4 does not act so as to impair the drive sensitivity. In addition, since the yoke 9 is formed in a simple U-bottom groove to form a simple magnetic circuit, the number of parts is reduced, the processing and the number of assembly steps are reduced, and the cost can be reduced.

Although three magnets are provided on one side, one magnet with multiple poles may be used. FIG. 4 shows a second embodiment of the present invention, and portions corresponding to those of the first embodiment are denoted by the same reference numerals. In this embodiment, one end 6j of the spring 6 is fixed to a spring fixing portion 2a protruding from the holding member 2 and is adhesively fixed. On the other hand, the other end 6e of the spring 6 is similarly fixed to a spring fixing portion 7a protruding from the fixing member 7. Thus, the spring 6 is provided so as to sandwich the holding member 2 and the magnet 11 in the Z direction. Note that a damper for covering the spring 6 is not shown.

With this configuration, the dimension of the optical system support device in the X direction can be further reduced.
Also, since the effective length of the spring 6 that bends in the X and Y directions can be increased, the displacement of the holding member 2 in the Y direction when the holding member 2 is displaced in the X direction can be reduced. Further, since the spring fixing member 2a of the holding member 2 does not protrude in the X direction, the holding member 2 can be reduced in weight, so that the driving sensitivity is improved and the inertia moment is reduced, but the resonance frequency around the Y axis is improved.

Further, there is an effect that resonance of the spring fixing portion 2a itself does not occur. The present invention is not limited to the above embodiments, and many modifications and variations are possible. For example, the shape of the spring may be as shown in FIG. FIG. A shows a case where a portion parallel to the Y direction is formed as one place, and FIG. B shows a case where there are two parallel portions but a bent portion is formed at a right angle. Further, there is no limitation on the driving means of the holding member. The driving direction of the holding member may be only the focus direction.

[0021]

According to the optical system supporting apparatus of the present invention, the holding member for holding the optical element is formed by a metal plate-like member including a portion elongated in at least the first direction with respect to the fixing member. In an optical system supporting device adapted to be supported in a movable state, the plate-shaped member may be a contact portion extending in a second direction substantially perpendicular to the first direction (for example, a protrusion in the embodiment). 6i, the present invention is characterized in that it includes a projection 6d), and that the corresponding contact part is in contact with the fixing member in the first direction, so that the present invention enables the support device to be assembled quickly and accurately. There is.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a plan view showing a first embodiment of the present invention.

FIG. 3 is an enlarged perspective view of a spring fixing portion.

FIG. 4 is a diagram showing a second embodiment of the present invention.

FIG. 5 is a plan view showing another example of a spring.

FIG. 6 is a diagram showing a conventional example.

FIG. 7 is a diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Objective lens 2 Holding member 6 Spring 6a Parallel part in tracking direction 6c Parallel part in tracking direction 7 Fixed member

Claims (1)

[Claims] A holding member for holding the optical element, the holding member including at least a portion elongated in a first direction in a first direction and supported by a metal plate member so as to be movable. In the optical system supporting device, the plate-shaped member includes a contact portion extending in a second direction substantially perpendicular to the first direction, and the contact portion contacts the fixed member in the first direction. An optical system supporting device, which is in contact with the optical system.