JPH11120584A - Objective lens drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily make a unit thin in an objective lens drive unit whose movable part provided with the objective lens is supported by four elastic members from a fixed part. SOLUTION: In an objective lens drive unit whose movable part provided with the objective lens is supported by four elastic members from a fixed part, an interval in the tracking direction between two sets of elastic members 70, whose positions in the focusing direction are almost the same, is made different. Otherwise, the fixing positions on the side of a fixing part and on the side of a movable part of the two sets of elastic members 70, whose positions in the focusing direction are almost the same, are shifted in the extending direction of the elastic members 70.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective lens driving device of an optical pickup device for optically recording or reproducing information on or from an optical recording medium, and more particularly to an objective lens driving device suitable for thinning.

[0002]

2. Description of the Related Art An optical pickup device for optically recording or reproducing data on or from an optical recording medium generally comprises an objective lens driving device having an objective lens and an optical system for transmitting and receiving light to and from the objective lens. Have been. The objective lens driving device includes a movable section having an objective lens, a focusing coil and a tracking coil, and a fixed section having a magnetic circuit, and the movable section is supported by the fixed section.

[0003] As a method of supporting the movable portion, a method of supporting the movable portion with four elastic members arranged in parallel is known.
In this supporting method, as shown in FIG.
The movable portion is supported by four elastic members 122 arranged on both sides of the movable member 9, and a pair of elastic members 122 on each side are arranged at regular intervals in the focusing direction (Z direction). (See Japanese Utility Model Publication No. 1-32176).

The four elastic members 122 are electrically conductive, and also serve as lead wires for supplying a driving current to the focusing coil 113 and the tracking coils 117 and 118. Each coil is electrically connected on the movable section side. Further, the elastic member 122 is electrically connected to a driving circuit that supplies a driving current to the objective lens driving device on the fixed portion side.

[0005] In addition, the connection between the elastic member and each coil,
A printed circuit board (relay board) is often used to connect the elastic member to the drive circuit (Japanese Patent Publication No. 4-49174).

[0006]

SUMMARY OF THE INVENTION As described above,
In order to reduce the thickness of the objective lens driving device supported by four parallelly arranged elastic members, it is necessary to reduce the spacing between the elastic members in the focusing direction (Z direction).

However, if the spacing between the elastic members in the focusing direction (Z direction) is reduced, the spacing between the lands of the printed circuit board (relay board) to which the elastic members are soldered must be reduced, making the soldering operation difficult. , And there was a limit to the narrowing interval. Therefore, it has been difficult to reduce the thickness of the objective lens driving device.

Accordingly, the present invention provides an objective lens driving device in which a movable portion having an objective lens is supported by a fixed portion with four elastic members, and the thickness of the objective lens driving device is easily reduced. It is.

[0009]

According to a first aspect of the present invention, there is provided an objective lens driving device, wherein a movable portion having an objective lens is supported by a fixed portion by four elastic members. Are different in the spacing in the tracking direction between two sets of elastic members having substantially the same position.

According to a second aspect of the present invention, in the objective lens driving device wherein the movable portion having the objective lens is supported by the fixed portion by four elastic members, the positions in the focusing direction are substantially the same. The fixed positions of the two sets of elastic members on the fixed part side and the movable part side are shifted in the direction in which the elastic members extend.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A configuration example of an objective lens driving device according to the present invention will be described with reference to the drawings.

[First Structure] FIG. 1 is a perspective view showing a first structure of an objective lens driving device according to the present invention.
Is a sectional view taken along the line AA ′.

The movable part of the objective lens driving device comprises an objective lens 10, a focusing coil 30, and a lens holder 20 having a tracking coil 40. Further, the fixing portion is composed of a base 80 having a supporting base 81 for fixing the permanent magnet 50 and the elastic member 70 and a base substrate 82.
0 is folded up. Further, the movable part is supported by four elastic members 70 from a fixed part.

The focusing coil 30 and the tracking coil 40 provided in the movable portion are arranged in a magnetic gap of a magnetic circuit composed of a permanent magnet 50 and a yoke 60 provided in a fixed portion. , A driving force in the focusing direction or the tracking direction is obtained. The driving force and the support force from the elastic member 70 are applied to the movable portion, and position control for moving the objective lens 10 in the focusing direction or the tracking direction is performed by balancing the two.

Next, the arrangement of the four elastic members will be described with reference to FIG. FIG. 2 shows a cross section parallel to the focusing direction and the tracking direction.

In FIG. 2, elastic members 70a and 70b
Means that the position in the focusing direction is the same and the objective lens 1
It is arranged almost symmetrically with respect to the optical axis of zero. The elastic members 70c and 70d also have the same position in the focusing direction and are arranged substantially symmetrically with respect to the optical axis of the objective lens 10.

Since the distance L2 between the elastic members 70c and 70d in the tracking direction is larger than the distance L1 between the elastic members 70a and 70b in the tracking direction, the holder to which the ends of the elastic members 70a and 70c are fixed by soldering. The substrate 21a and the holder substrate 21b to which the ends of the elastic members 70b and 70d are fixed by soldering are arranged obliquely with respect to the focusing direction.

Therefore, the distance L4 between the elastic members 70a and 70c on the holder substrate 21a is larger than the difference L3 between the positions in the focusing direction. Similarly, the distance L4 between the elastic members 70b and 70d on the holder substrate 21b.
Is larger than the difference L3 in the focusing direction.

As described above, the elastic member holder substrate 21b
By setting the distance L4 above to be larger than the difference L3 between the positions in the focusing direction, the tip of the elastic member is fixed by soldering even if L3 is reduced due to the reduction in the thickness of the objective lens driving device. The land interval on the holder substrate can be increased. Also, the soldering operation can be easily performed.

Since L4 can be increased by increasing the difference between L1 and L2, the size of L4 can be adjusted by adjusting the difference between L1 and L2. By adjusting the difference between L1 and L2, L4
L3 can be reduced while maintaining a constant value, so that the objective lens driving device can be easily made thinner.

Although the other end of the elastic member is fixed to the base substrate 82 by soldering, the same effect can be obtained on the base substrate 82 side.

[Second Configuration] FIG. 3 is a perspective view showing a second configuration of the objective lens driving device according to the present invention. Second
Is also similar to the first configuration in the configuration of the movable portion and the fixed portion, but is different from the first configuration in a portion for fixing the distal end of the elastic member to the lens holder 20 side.

In the second configuration, a step portion for fixing an elastic member is provided on a side surface of the lens holder 20, and an elastic member 70b is provided on the upper step 22a, and a lower step 22b is provided on the lower step 22b.
The elastic member 70d is fixed by an adhesive 23. A coil end is entangled with the protruding portion 22c of the stair portion, and furthermore, the portion is soldered with solder 24 to secure electrical connection between the elastic member and the coil.

The portions where the elastic members 70a and 70c are fixed by soldering are similarly fixed by soldering.

By doing so, the elastic members 70b and 70b
Even if the difference L3 in the position d in the focusing direction is reduced, only the step between the upper step 22a and the lower step 22b is reduced, so that the soldering operation can be easily performed even if L3 is reduced. Therefore, similarly to the first configuration, the objective lens driving device can be easily reduced in thickness.

Regarding the soldering of the protruding portion 22c,
As shown in FIG. 4, soldering may be performed without tangling the coil terminals.

Alternatively, the elastic members 70b and 70d may be fixed to the lens holder (movable part) by insert molding shown in FIG. 5 without being fixed by the adhesive. Incidentally, insert molding may be used for fixing the elastic member on the fixing portion side.

[Third Configuration] FIG. 6 is a perspective view showing a third configuration of the objective lens driving device according to the present invention. The arrangement of the elastic members in the third configuration will be described with reference to FIG.

As shown in FIG. 6, the four elastic members 70
a and 70b and the elastic members 70c and 70d are arranged so that the positions in the focus direction are the same. In the third configuration, the elastic member 70b soldered and fixed to the movable portion
And 70d are shifted by L5. or,
The soldering position on the fixed part side is also shifted by L5,
The lengths 0b and 70d from the fixed position on the fixed portion side to the fixed position on the movable portion side are fixed.

The portions where the elastic members 70a and 70c are fixed by soldering are similarly arranged. Therefore, the fixed positions of the elastic members 70a and 70b and the elastic members 70c and 70d on the fixed portion side and the movable portion side are shifted by L5 in the extending direction (on the extension line) of the elastic member, and the four elastic members are fixed. The length from the soldering fixed position on the part side to the soldering fixed position on the movable part side is equal.

With such a configuration, even if the distance between the elastic members in the focus direction is reduced, the land distance on the holder substrate 21 and the base substrate 82 for fixing the elastic members by soldering can be increased. In addition, the thickness of the objective lens driving device can be easily reduced, and the soldering operation can be easily performed.

It should be noted that there is a difference in the spacing in the tracking direction between the two sets of elastic members having substantially the same position in the focusing direction, and the fixed and movable parts of the two sets of elastic members having substantially the same position in the focusing direction. May be shifted in the extending direction (on the extension line) of the elastic member.

In the case where the elastic member is fixed by an adhesive as in the second configuration, the fixed positions of the fixed portion and the movable portion are set in the extending direction (on the extension line) of the elastic member.
May be shifted.

[0034]

As described above, by providing a difference in the spacing in the tracking direction between two sets of elastic members having substantially the same position in the focusing direction, it is possible to easily realize a thin objective lens driving device. it can.

Further, even when the thickness of the objective lens driving device is reduced, the soldering operation can be easily performed.

The same applies even if the soldering fixing positions on the fixed portion side and the movable portion side of the two sets of elastic members having substantially the same position in the focusing direction are shifted in the direction in which the elastic members extend (on the extension line). The effect is obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an objective lens driving device according to the present invention (first configuration).

FIG. 2 is a cross-sectional view (a cross-section of FIG. 1AA ′) showing the objective lens driving device according to the present invention (first configuration).

FIG. 3 is a perspective view showing an objective lens driving device according to the present invention (second configuration).

FIG. 4 is a perspective view showing a portion for soldering and fixing an end of an elastic member to a lens holder side (second configuration).

FIG. 5 is a perspective view showing a portion for soldering and fixing an end of an elastic member to a lens holder side (second configuration).

FIG. 6 is a perspective view showing an objective lens driving device according to the present invention (second configuration).

FIG. 7 is a perspective view showing a conventional objective lens driving device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Objective lens 20 Lens holder 21 Holder substrate 22 Step part 23 Adhesive 24 Solder 30 Focusing coil 40 Tracking coil 50 Permanent magnet 60 Yoke 70, 70a, 70b, 70c, 70d Elastic member 80 Base 81 Support base 82 Base substrate

Claims (2)

[Claims] 1. An objective lens driving device in which a movable portion having an objective lens is supported by a fixed portion by four elastic members, wherein two sets of elastic members having substantially the same position in the focusing direction in the tracking direction. Objective lens driving device with different intervals. 2. An object lens driving device in which a movable section having an objective lens is supported by a fixed section by four elastic members, wherein two sets of elastic members having substantially the same position in the focusing direction are provided on the fixed section side. And an objective lens driving device in which a fixed position on the movable portion side is shifted in a direction in which the elastic member extends.