JPH05109098A - Objective lens driving device - Google Patents

Abstract

PURPOSE:To provide an inexpensive objective lens driving device which is used for optical pickup devices for optical disk devices, hologram device, etc., is less in the weight balance shifting of its mobile section, and has an excellent servo characteristic. CONSTITUTION:A lens collision preventing member 11 on the upper surface of the objective lens holder 2 of this objective lens driving device is constituted of an elastic bonding agent. As a result, the number of parts used in this driving device can be reduced and the member 11 can be miniaturized. Therefore, the influence to the weight balance of the mobile section can be reduced and the servo characteristic of this driving device can be improved. In addition, the cost of the device can be reduced.

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 for adjusting an irradiation position of a light beam by displacing an objective lens in an optical pickup used for an optical disk device, a hologram device or the like.

[0002]

2. Description of the Related Art In an optical disk device, by moving the entire optical pickup in the tracking direction of a rotating optical disk (radial direction of the disk), an arbitrary track can be selected for recording and reproduction. .. Further, the optical pickup device has an objective lens driving device that adjusts the irradiation position of the light beam by subtly displacing the objective lens. This objective lens driving device adjusts the focus of the light beam by displacing the objective lens in the optical axis direction, and also adjusts the tracking by displacing the objective lens in the tracking direction on a plane orthogonal to the optical axis. Is to do.

A movable part supporting member for displacing a movable part composed of an objective lens, an objective lens holder, a coil or a magnet in a focusing direction and a tracking direction includes a resin hinge, a wire, a leaf spring, etc., and a conventional optical pickup. An objective lens driving device in the apparatus will be described with reference to FIG. 2 using a wire as an example.

The objective lens 1 of the optical system is held by the objective lens holder 2 with its periphery fixed. The objective lens holder 2 has a hole 2a in the center thereof, and the magnet 3 is fixed to the hole 2a so as to face the hole 2a. The tracking coil 4 and the focus coil 5 wound around the yoke 6 are located at the center of the magnets 3 facing each other in the hole 2a and fixed to the base 8. Four parallel linear movable part support members 7a, 7b, 7
One end of each of c and 7d is fixed to the objective lens holder 2 and the other end is fixed to the support member fixing portion 9 of the base 8 so as to support the movable portion so as to be movable in two directions of the focus direction and the tracking direction. .. The base 8 is attached to the tip of an optical pickup body (not shown), and irradiates the optical disc through the objective lens 1.

In the objective lens driving device, when the tracking coil 4 is appropriately energized, the objective lens holder 2 is moved in parallel in the tracking direction by electromagnetic action. Therefore, it is possible to adjust the tracking of the light beam applied to the optical disc through the objective lens 1. When the focus coil 5 is appropriately energized, the objective lens holder 2 is moved in parallel in the focus direction by electromagnetic action. Therefore, the focus of the light beam with which the optical disc is irradiated through the objective lens 1 can be adjusted.

Further, in recent years, optical pickups have become smaller and thinner, and the gap between the objective lens and the optical disc has become smaller, so that the collision between the objective lens and the optical disc can be prevented.
A lens collision prevention member 10 made of an elastic material such as resin is fixed at a position facing the objective lens on the objective lens holder.

[0007]

However, in the above-mentioned conventional structure, the weight variation of the movable portion is affected by the variation in the attachment of the lens collision prevention member 10 and the variation in the component accuracy, and the servo characteristics become unsatisfactory due to rolling and yawing. There was a problem of becoming stable. Further, there is a problem of high cost due to an increase in the number of parts.

The present invention solves the above problems,
An object of the present invention is to provide a low-cost objective lens driving device that has little influence on the weight balance of the movable part, has excellent servo characteristics, and has a small number of parts.

[0009]

In order to achieve this object, the objective lens driving device of the present invention is provided with a lens collision preventing portion made of an elastic adhesive on the objective lens holder to prevent collision between the objective lens and the optical disk. It is configured to prevent.

[0010]

With this configuration, there is little influence on the weight balance, and rolling and yawing hardly occur, so that stable servo characteristics can be obtained. Furthermore, the number of parts can be reduced,
Cost reduction is possible.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention and is a perspective view of an objective lens driving device. In addition,
Components having the same functions as those of the conventional example shown in FIG. 1 are designated by the same reference numerals.

The objective lens 1 of the optical system is held by the objective lens holder 2 with its periphery fixed. This objective lens holder 2 is provided with a hole 2a at the center thereof, and a magnet 3 is fixed so as to face the hole 2a and constitutes a movable portion in the objective lens driving device. The tracking coil 4 and the focus coil 5 wound around the yoke 6 have the holes 2
It is located at the center of the magnet 3 facing a and is fixed to the base 8. Four parallel linear movable part support members 7a, 7
b, 7c and 7d have one end of the objective lens holder 2
In addition, the other end is fixed to the support material fixing portion 9 of the base 8, and supports the movable portion so as to be movable in two directions of the focus direction and the tracking direction. The base 8 is attached to the tip of an optical pickup body (not shown) so that the optical disk is irradiated with the light through the objective lens 1.
Further, the collision of the objective lens 1 and the optical disk is prevented by the lens collision prevention member 11 in which the elastic adhesive is dropped on the upper surface of the objective lens holder 2 so as to be higher than the objective lens 1.

In the objective lens driving device, when the tracking coil 5 is appropriately energized, the objective lens holder 2 is moved in parallel in the tracking direction by electromagnetic action. Therefore, it is possible to adjust the tracking of the light beam applied to the optical disc through the objective lens 1. Further, when the focus coil 5 is appropriately energized, the objective lens holder 2 is moved in parallel in the focus direction by electromagnetic action. Therefore, the focus of the light beam with which the optical disc is irradiated through the objective lens 1 can be adjusted.

In this embodiment, the lens collision prevention member 1
By configuring 1 with an elastic adhesive, it is possible to reduce the number of resin parts and downsize the lens collision prevention member 11. Therefore, the influence on the weight balance of the movable portion is reduced, and rolling and yawing are less likely to occur, so that stable servo characteristics can be obtained.

Further, by providing the lens collision prevention member 11 in the vicinity of the objective lens 1, the objective lens can also be bonded and the number of steps can be reduced.

[0016]

As described above, according to the present invention, since the lens collision prevention member is made of the elastic adhesive, the number of parts can be reduced and the collision prevention member can be downsized, and the influence on the weight balance of the movable portion can be improved. It is possible to realize a low-cost objective lens driving device which has excellent servo characteristics in which rolling and yawing hardly occur.

[Brief description of drawings]

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

FIG. 2 is a perspective view of an objective lens driving device according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Objective lens 2 Objective lens holder 3 Magnet 4 Tracking coil 5 Focus coil 6 Yoke 7a-7d Movable part supporting material 8 Base 9 Supporting material fixing part 11 Lens collision prevention member

Front page continued (72) Inventor Tetsuro Shimamura 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Yoshiaki Ikeda 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Invention Kenichiro Urairi 1006 Kadoma, Kadoma-shi, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. An objective lens holder having an objective lens on at least an upper surface, a magnet or a coil on a side surface, and a notch or a hole portion on a central side surface, and a collision between the objective lens and a disk on the objective lens holder. A lens collision prevention portion made of an elastic adhesive, a coil or a magnetic circuit having the magnet provided so as to face the magnet or the coil, and a movable portion supporting member that enables the objective lens holder to operate in the focus direction and the tracking direction. And an objective lens driving device comprising a support material fixing portion for fixing the movable portion support material. 2. An objective lens driving device, wherein a lens collision prevention unit is arranged near the objective lens.