JPS63224039A - Objective lens driving device - Google Patents

Abstract

PURPOSE:To prevent the breaking of wire of a coil by bonding a leaf spring and a conductive material through a viscoelastic material, and soldering a coil for a focusing or the coil for a tracking to the conductive material, on the fixed part of the leaf spring. CONSTITUTION:The conductive material 12 such as a copper foil or the like is bonded to the leaf spring 5d or the like through the viscoelastic material 11, and the coil 9 for the focusing or the coil 8 for the tracking is soldered to the top of the lens holder 2 of the conductive material 12. Thus, because the contact point of the coil does not vibrate, a wire is not broken, and reliabil ity is much improved. Besides, because plural conductive parts can be formed on one sheet of the leaf spring, the number of the leaf springs can be reduced, compared with a case that the spring itself is made of the conductive material.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an objective lens driving device for an apparatus for optically writing or reading information.

Conventional technology Objective lens drive devices drive an objective lens with light in a direction perpendicular to the surface of the recording medium in order to correct focus shifts caused by vertical movement of warped disk-shaped recording media such as compact discs, and tracking shifts caused by eccentricity. It is driven in two axes: an axial direction (hereinafter referred to as focus direction F) and a radial direction parallel to the recording medium surface (hereinafter referred to as tracking direction T).

A conventional objective lens driving device of this type has a structure as shown in FIG. 4, for example.

That is, for driving in the focus direction F, the lens holder 2 to which the objective lens 1 is attached is driven by the magnet 6a.

The plate panels esa and sb are connected to the intermediate support portion 3 by an electrodynamic transducer in which a focusing coil 9 is installed in the gap of a magnetic circuit consisting of the magnetic yokes 6b and 7b.
It is obtained by translational movement through .

For driving in the tracking direction T, the lens holder 2 to which the objective lens 1 is attached is driven by the magnets ea, eb and the magnetic yoke 7a.
, 7b, a plate spring SC is connected to the fixed part 4 by an electrodynamic transducer in which a tracking coil 8 is arranged in the gap of the magnetic circuit.

It is obtained by translation through 5d.

In addition, the entire objective lens drive device is driven by a motor to access the recording medium in the access direction d.

Problems to be Solved by the Invention However, in the objective lens drive device having the structure as shown in FIG. 4, the end of the focusing coil 9 or tracking coil 8 is mounted on the base 10 as shown in FIG. A drive current is applied to the focusing coil or tracking coil 8 by soldering to the board 13 that has been mounted.
There has been a problem in that the focusing coil 9 or the tracking coil 8 may break due to repeated stress generated at the contact portion between the focusing coil 9 or the tracking coil 8.

SUMMARY OF THE INVENTION Therefore, the present invention provides an objective lens drive device having a plate spring that can be easily installed and that can apply a drive current with high reliability.

Means for Solving the Problems The technical means of the present invention for solving the above problems is that the leaf spring and the conductive material for sending a driving current to the movable part are adhesively fixed via a viscoelastic material. The structure is as follows.

Effect of the Invention With the above-described configuration, the focus coil or tracking coil can be soldered, for example, on the lens holder, and when the movable part is driven, the contacts of the focus coil or tracking coil do not vibrate, thereby preventing coil breakage. It can be prevented.

Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a perspective view of an objective lens driving device according to an embodiment of the present invention.

The lens holder 2 to which the objective lens 1 is attached is attached to the magnet ea
, eb and magnetic yokes ya, yb, and an electrodynamic transducer in which a focusing coil 9 and a tracking coil 8 are arranged in the gap of a magnetic circuit, the plate springs 61L,
Its drive is obtained by translational movement in the focus direction F and tracking direction T via esb, 50, 5+1, respectively.

Note that one end of the leaf springs 50, 5d is fixed to both ends of the fixing part 4 fixed near the end of the pace 1o, and the other end is fixed to both ends of the intermediate support part 3. Further, the substantially U-shaped plate spring 51L has both ends thereof fixed to both ends of the upper surface of the lens holder 2, and the other end thereof to the upper surface of the intermediate support portion 3. Both ends are fixed to the lower surface of the lens holder 2, and the other end is fixed to the lower surface of the intermediate support section 3.

11 is a viscoelastic material fixed to the surface of the leaf springs 6a to 6d, and a conductive material 12 is provided on each of the viscoelastic materials 11, and each end of the conductive material 12 is connected with a lead wire. ing.

To explain in more detail below, for example, as shown in FIG. 2, a conductive material 12 such as steel foil is bonded to a plate spring 6d etc. via a viscoelastic material 11, and a focusing coil 9 or a tracking coil is attached. The coil 8 is soldered onto the lens holder 2 of the conductive material 12 as shown in FIG. In this embodiment, due to the above-described configuration, the contacts of the coil do not vibrate, so there is no disconnection and reliability is greatly improved. Furthermore, as shown in FIG. 1, since a plurality of conductive parts can be formed on one leaf spring, the number of leaf springs can be reduced compared to when the leaf spring itself is made of a conductive material.

Furthermore, since the viscoelastic material 11 is used, it goes without saying that the change in the spring constant due to adhesion of the conductive material 12 is very small and stable displacement frequency characteristics can be maintained.

Effects of the Invention The present invention provides an objective lens drive device of the type that obtains drive in either or both of the focus direction F and the tracking direction T by translating a movable part via a plurality of parallel leaf springs. Then, a leaf spring and a conductive material are bonded via a viscoelastic material, and a focusing coil or a tracking coil is soldered to the conductive material on the fixed part of the leaf spring, thereby driving the movable part. At the same time, since the coil does not vibrate, the coil does not break due to repeated stress, making it possible to design a highly reliable objective lens drive device.

[Brief explanation of drawings]

Fig. 1 is a perspective view of an objective lens drive device according to an embodiment of the present invention, Fig. 2 is a perspective view of main parts showing the configuration of an embodiment of the present invention, and Fig. 3 is a perspective view of a conventional example 9 objective lens drive device. FIG. 4 is a perspective view of a conventional objective lens driving device. 1...Objective lens, 2...Lens holder, 3...Intermediate support part, 4...Fixing part, 6&~6d... Plate yoke, 8...Tracking coil, 9°...°°focus cocoil 1o...Pace, 11...Viscoelastic material, 12... - Conductive material, 13...Substrate. Name of agent: Patent attorney Toshio Nakao and one other person J-
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Claims (2)

[Claims] (1) In an objective lens driving device of a device for optically writing or reading information on a recording medium, a movable part consisting of an objective lens and a lens holder is moved in the optical axis direction perpendicular to the surface of the recording medium and in the optical axis direction perpendicular to the surface of the recording medium. a mechanism for driving in a radial direction parallel to the surface of the recording medium, and the movable section is configured to move in translation in one or both of the optical axis direction and the radial direction. The part and the fixed part are connected by a plurality of parallel leaf springs, and the leaf spring and a conductive material for sending a driving current to the movable part are adhesively fixed via a viscoelastic material. Objective lens drive device. (2) The objective lens driving device according to claim 1, characterized in that steel foil is used as the conductive material.