JPS62197932A - Driving device for objective lens - Google Patents

Abstract

PURPOSE:To reduce the number of parts and to facilitate assembling without lowering accuracy by forming plural springs that works as supporting members and a joining part that joins them integrally to make a movable electromagnetic unit movable in two dimensional directions. CONSTITUTION:A movable electromagnetic unit 2 is provided with a bobbin 18 for winding coil and an assembled objective lens 1 is mounted to the bobbin 18 and held by the movable electromagnetic unit 2. A pair of springs 7, 7 for focusing direction, a pair of springs 8, 8 for track direction and a joining part 5 of a supporting member 3 are formed integrally by using a material made of synthetic resin or rubber. The supporting member 3 supports a movable electromagnetic unit 2 to the body 4 of a driving device by making the movable electromagnetic unit 2 movable in focus direction and track direction to the body 4 of the driving device. Thus, the number of parts can be reduced and assembling is made easy without reducing the accuracy of assembling.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to an objective lens driving device installed in an optical information reproducing device that reads information recorded on an optical disk or an optical information recording device that records information on an optical disk. Regarding improvements.

(Prior art and its problems) Conventionally, an optical information reproducing device that reads information recorded on an optical disk or an optical information recording device that records information on an optical disk is equipped with an objective lens drive device. . The driving device for this objective lens is shown in Fig. 6.
As shown in FIG. 7, it has a movable electromagnetic unit 2 that integrally holds an objective lens 1, and this movable electromagnetic unit 2 is supported by a drive device main body 4 via a support member 3.

The support member 3 includes one end of a pair of focus direction springs 7.7 that apply a force to return the optical disk 6 in the focus direction to the coupling portion 5, and a 1-rack that provides a force to return the optical disk 6 in the track direction. One end of the direction spring 8.8 is attached, the other end of the pair of focus direction springs 7.7 is attached to the movable electromagnetic unit 2, and the other end of the pair of track direction springs 8.8 is attached. It is configured by being attached to the drive device main body 4. Is the objective lens 1 the movable electromagnetic unit 2? By moving in the direction against the return force of the focus direction spring 7.7, it is moved in the focus direction F shown in FIG. 7, and also in the direction against the return force of the track direction spring 8.8. By doing so, it can be moved in the track direction T shown in FIG.

By the way, in this way, so that the movable electromagnetic unit that integrally holds the objective lens is movable in at least two-dimensional directions, the support member that supports the movable electromagnetic unit applies a return force in at least the two-dimensional direction to the movable electromagnetic unit. In a conventional objective lens drive device that is composed of a plurality of springs attached to an electromagnetic unit and a coupling part that couples the ends of the plurality of springs, the focus direction The spring 7.7 and the track direction springs 8, 8 are made of metal plate springs and are formed separately from the coupling part 5, in order to satisfy the characteristics required for an objective lens drive device. Another problem is that the support member 3 must be assembled with strict accuracy, making assembly difficult. Furthermore, since there are many parts that make up the support member 3, it is difficult to manage each part, leading to an increase in cost.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems, and is an objective lens that can reduce the number of parts per unit and facilitate assembly without impairing assembly accuracy. The purpose of the present invention is to provide a drive device for the following.

(Means for Solving the Problems) A feature of the objective lens driving device according to the present invention is that the movable electromagnetic unit that holds the objective lens integrally is movable in at least two-dimensional directions. A plurality of springs as constituent elements of a support member that supports the drive device main body and a connecting portion that connects the ends of the plurality of springs are integrally formed of a synthetic resin material or a rubber material. It's where you are.

(Example) An example of an objective lens driving device according to the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, the driving device body 4 has a circular recess 10 formed in its lower part. This recess 10
, a disc-shaped focusing magnet 11 and a disc-shaped focusing yoke 12,13 are incorporated. The focusing magnet 11, the disc-shaped focusing yoke 12, and the drive device main body 4 have through holes 14, 15, .
16 are formed respectively.

A cylindrical portion 17 extending toward the movable electromagnetic unit 2 is formed at the center of the focusing yoke 13 .

The focusing magnet 11 is connected to the focusing yoke 12.1.
The focusing magnet 11 and the focusing yokes 12 and 13 constitute a focusing closed magnetic circuit that drives the movable electromagnetic unit 2 in the focusing direction.

The movable electromagnetic unit 2 has a bobbin 18 for winding a coil. The objective lens 1 is held by the movable electromagnetic unit 2 with the objective lens assembly attached to the upper end of the coil winding bobbin 18. The movable electromagnetic unit 2 is supported by the drive main body 1 so as to be movable in the focus direction and the track direction of the optical disc 6 via a support member 3. The coil winding bobbin 18 has a pair of track direction coil winding parts 19.
19, and a focus direction coil winding part 20.

21.22 is the coil winding part 19.1 for the track direction.
9 shows a coil wound around the focus direction coil winding part zO. The pair of track direction coil winding parts 19 and 19 are arranged at symmetrical positions on the outer circumference of the coil winding bobbin 18, and the focus direction coil winding part 20 is arranged at the lower end of the coil winding bobbin 18. It is set in. The focusing direction coil winding section 20 is configured to face the focusing magnet 11 through the first through hole 16.15, and the cylindrical body section 17 of the focusing yoke 13 enters the lower part of the coil winding bobbin 18. The structure is as follows.

At the top of the drive device main body 4, there are struts 23.23.24.2.
4 is provided protrudingly. This pillar 23.23.24.24
has the function of positioning and attaching the trunk direction magnets 25 and 26 and the truck direction yokes 27 and 28 to the drive device main body 4. The track direction magnet 25 and the track direction magnet 26 are configured to face each other with the same polarity facing each other, and a track direction coil is wound between the track direction magnet 25 and the track direction magnet 26. The rotating portion 19.19 is configured to enter. The track direction magnets 25 and 26 and the track direction yoke 2
7.28 constitute a set of track dose magnetic circuits.

A current corresponding to the track error signal is applied to the coil 21.21, and a current corresponding to the focus error signal is applied to the coil z2.
The track dose magnetic circuit for the coil 21 is arranged in such a direction that electromagnetic force is generated in the track direction T when the coil 21 is energized, and the focusing closed magnetic circuit for the coil 22 is arranged in the direction such that an electromagnetic force is generated in the track direction T when the coil 21 is energized. When the coil 22 is energized, an electromagnetic force is generated in the focus direction F, and the coils 21 and 21 are wound in the same direction so that electromagnetic force in the track direction is generated in the same direction.

As shown in FIG. 3, the support member 3 has a pair of focus direction springs 7.7 and a pair of track direction springs 8.8.
and the connecting portion 5 are integrally formed of a synthetic resin material or a rubber material. A pair of focus direction springs 7
．． 7 and the pair of track direction springs 8, 8 are plate-shaped here. A pair of focus direction springs 7.
7 are configured to face each other with an interval in the focus direction.

It has a function of applying a force to the electromagnetic unit 2 to return the optical disc 6 in the focusing direction. The pair of track direction springs 8.8 are configured to face each other with an interval in the track direction, and have a function of applying a return force to the movable electromagnetic unit 2 in the track direction of the optical disc 6.

One end of the upper focus direction spring 7 is coupled to the upper end of the coil winding bobbin 18, and one end of the lower focus direction spring 7 is coupled to an axially intermediate portion of the coil winding bobbin 18. combined. Bobbin 1 for winding the coil
8 has flanges 29 and 30 formed at its upper end and middle part, respectively, for attaching the end of the focus direction spring 7.7.

One end of the pair of track direction springs 8.8 is attached to the support column 24.24. The support member 3 thereby supports the movable electromagnetic unit 2 on the drive device main body 4 so that the movable electromagnetic unit 2 is movable relative to the drive device main body 4 in the focus direction and the track direction of the optical disk 6. It is something.

FIG. 4 shows another embodiment of the support member of the objective lens driving device according to the present invention, in which a focus direction spring 7 is shown.
．． 7 and the track direction spring 8.8 are connected to the rod-shaped spring member 31.
The connecting portion 5 is attached to the drive device main body 4. According to this embodiment, the rod-shaped spring member 31 applies a return force in the focus direction and a return force in the track direction to the electromagnetic unit 2.

FIG. 5 shows still another embodiment of the support member of the objective lens drive device according to the present invention, in which the ends of a pair of track direction springs 8.8 are attached to the drive device main body 4. 3z
The configuration is such that the According to this example,
Compared to the first embodiment described above, attachment of the support member 3 to the drive device main body 4 is easier.

In the embodiments described above, the objective lens 2 is moved in the two-dimensional direction of the focus direction and the track direction of the optical disc 6, but the electromagnetic unit 2 is also moved in the tangential direction of the optical disc 6.

It is also possible to adopt a configuration in which the movable unit 2 is moved in three-dimensional directions.

(Effects of the Invention) As explained above, the objective lens driving device according to the present invention moves the movable electromagnetic unit that holds the objective lens together so that the movable electromagnetic unit is moved in at least two dimensions. Since the plurality of springs as the constituent elements of the support member supported on the drive device main body and the joint portion that connects the ends of the plurality of springs are integrally formed from a synthetic resin material or a rubber material, This has the effect that the number of parts can be reduced and assembly can be facilitated without impairing assembly accuracy.

[Brief explanation of drawings]

FIG. 1 is a plan view of an objective lens driving device according to the present invention;
2 is a cross-sectional view of the objective lens driving device shown in FIG. 1 taken along the line A-A, FIG. 3 is a perspective view of the support member shown in FIG. 1, and FIG. FIG. 5 is a perspective view showing still another embodiment of the support member, and FIG. 6 is a plan view showing the configuration of a conventional objective lens driving device. FIG. 7 is a cross-sectional view of the objective lens driving device shown in FIG. 6 taken along line BB. 1...Objective lens 2...Movable electromagnetic unit 3...Supporting member 4...Driver main body 5...Joining part 7...Focusing spring 8...Track direction spring Fig. 3 Figure 5

Claims (1)

[Claims] (1) A support member that supports the movable electromagnetic unit applies a return force in at least the two-dimensional direction to the movable electromagnetic unit so that the movable electromagnetic unit that holds the objective lens integrally is moved in at least two dimensions. In an objective lens driving device comprising a plurality of springs and a connecting portion that connects ends of the plurality of springs, the plurality of springs and the connecting portion are made of a rubber material or An objective lens driving device characterized in that it is integrally formed of a synthetic resin material.