KR19990016459A - Optical Pickup Actuator - Google Patents

Abstract

The present invention relates to an optical pickup actuator that maximizes the damping characteristics of an actuator for driving an objective lens in a vertical or horizontal direction and enables miniaturization.

The movable part of the optical pickup actuator of the present invention includes a spring means having an elastic force, a lens holder in which the spring means is positioned on its side wall and a protrusion is formed on one side of the side wall, and damping means positioned on the side wall.

The optical pickup actuator of the present invention has an advantage of maximizing damping characteristics and realizing miniaturization.

Description

Optical Pickup Actuator

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup, and more particularly, to an optical pickup actuator that maximizes the damping characteristics of an actuator that drives an objective lens in a vertical or horizontal direction and enables miniaturization.

Recently, various products for recording / reproducing information of an optical disc have been developed due to the rapid development of the optical disc. Among these, an objective lens driving device is provided with the optical pickup, which makes the optical spot follow the center of the signal track of the optical disk with respect to the surface vibration and eccentricity of the optical disk caused by the rotation of the optical disk. . The objective lens driving apparatus is called an optical pickup actuator and drives the objective lens to perform focusing and tracking operations. The focusing operation is to drive the objective lens up and down so that the light spot of the light beam from the objective lens falls within the depth of focus in the signal track of the optical disc. The tracking operation is to drive left and right so that the light spot of the light beam from the objective lens follows the center of the signal track of the optical disc. Optical pickup is becoming thinner, and the optical pickup actuator that moves the objective lens up and down (focusing servo) and left and right (tracking servo) by magnetic force by tracking servo and focusing servo has emerged as an urgent problem. .

The problem of the conventional optical pickup actuator will be described in detail with reference to FIG. 1.

1 is a perspective view of a conventional optical pickup actuator.

Referring to Figure 1, the conventional optical pickup actuator is largely composed of a movable portion 10 and a fixed 20, the movable portion 10 is a lens holder (1), focusing coil (2), tracking coil (; 3), The objective lens 8 and the first printed circuit board (hereinafter referred to as the first PCB, 9). The fixing part 20 is composed of a yoke 5, a permanent magnet 4, a frame 6, and a second printed circuit board 11 hereinafter.

The movable part 10 and the fixed part 20 are connected by the wire spring 7. In the movable portion 10, the lens holder 1 has a cylindrical inner diameter, and the objective lens 8 is fitted to the inner diameter. The focusing coil 2 is wound around the outer periphery of the lens holder 1, and the tracking coil 3 is bonded onto the focusing coil 2. In the fixing portion 20, the permanent magnet 4 is bonded to both sides of the yoke 5 so as to face each other, and the yoke 5 is fixed to the frame 6.

The frame 6 is installed to give damping characteristics when the optical pickup actuator is driven, and an injection space is provided in the inside thereof so that the damper 12 made of a material having a predetermined spring constant and elastic modulus value can be injected and cured. .

However, the conventional optical pickup actuator has a limitation on the vertical height from the lowermost end of the yoke 5 to the uppermost side of the frame 6, thereby limiting the miniaturization since the distance from the uppermost surface of the frame to the disc surface is extremely small. Has been given.

In the conventional optical pickup actuator, the damper 12 is located on the rotation axis of the wire spring with a relatively small displacement of the wire spring, thereby causing a problem of lowering the efficiency of damping characteristics.

Accordingly, an object of the present invention is to provide an optical pickup actuator that maximizes the damping characteristics and enables miniaturization.

1 is a perspective view showing a conventional optical pickup actuator.

2 is a perspective view showing an optical pickup actuator according to an embodiment of the present invention;

Explanation of symbols for the main parts of the drawings

1, 11: Lens holder 2, 12: Focusing coil

3, 13: tracking coil 4, 14: permanent magnet

5, 15: York 6: frame

7, 17: wire spring 8, 18: objective lens

9, 19, 11, 21: PCB 12, 22: Damper

11a: protrusion 10, 30: movable part

20, 40: fixed part

In order to achieve the above object, the movable portion of the optical pickup actuator of the present invention is a spring means having an elastic force, a lens holder having a spring means is located on its side wall and a protrusion is formed on one side of the side wall, and a damping means located on the side wall Equipped.

The fixing part of the optical pickup actuator of the present invention includes a permanent magnet for generating magnetic force and a yoke positioned at the rear of the permanent magnet to prevent the magnetic flux of the permanent magnet from leaking.

Other objects and features of the present invention in addition to the above objects will become apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIG. 2.

2 is a perspective view showing an optical pickup actuator according to an embodiment of the present invention.

In the configuration of Figure 2, the optical pickup actuator of the present invention comprises a movable portion 30 and a fixed portion 40, the movable portion 30 is a lens holder 11, focusing coil 12, tracking coil 13, It consists of an objective lens 18 and a first PCB 19. And the fixing part 40 is composed of a yoke 15, a permanent magnet 14, the second PCB (21).

The movable portion 30 and the fixed portion 40 are connected by a wire spring 17.

The wire spring 17 serves to supply current to the focusing coil 12 and the tracking coil 13 via the first PCB 19 and also to center one end portion thereof when the movable part 30 is driven. This serves to form a rotating shaft of the movable portion (30).

To this end, the wire spring 17 has elasticity and its one end and the other end thereof are connected to the first PCB 19 of the movable part 30 and the second PCB 21 of the fixing part 40, respectively. When the movable part 30 is driven, the rotating shaft becomes one end of the wire spring 17 connected to the second PCB 21.

The wire spring 21 may be replaced by a leaf spring having elasticity not shown.

The lens holder 11 has an objective lens 18 fitted to its inner diameter, and one side of the first PCB 19 and the wire spring 17 (or an unillustrated leaf spring) is fixed to the side wall thereof. The lens holder 11 has a protrusion 11a formed at one side of its stepped portion where the central portion of the wire spring 11 (or leaf spring) is located. The damper 22 having a predetermined spring constant and modulus of elasticity is injected and cured into the protrusion 11a of the lens holder 11.

Therefore, the damper 22 is injected into the central portion where the displacement of the wire spring 17 is large when the movable part 30 is driven, thereby maximizing the damping effect.

The fixing part 40 is made of a configuration in which the conventional frame 6 is omitted. The yoke 15 of the fixing part 40 is made of magnetic material of steel system to prevent the magnetic flux of the permanent magnet 14 from leaking. The permanent magnet 14 forms a magnetic circuit with the focusing coil 12 and the tracking coil 13 of the movable portion.

The vertical height of the fixing part 40 in which the conventional frame 6 is omitted is reduced by at least 1 mm as compared with the conventional vertical distance by the vertical distance from the lowest end surface of the yoke 15 to the uppermost surface.

The objective lens 18 is driven in the vertical direction (focusing direction) or the left and right direction (tracking direction) by the driving of the movable part 30. In detail, the current flows through the focusing coil 12 in the movable part 30 to focus. The objective lens 18 performs the focusing operation in the vertical direction by using the Lorentz force generated in the magnetic circuits of the coil 12 and the permanent magnet 14. The current flows through the tracking coil 13 and the objective lens 18 performs tracking in the horizontal direction by using the Lorentz force generated in the magnetic circuits of the tracking coil 13 and the permanent magnet 14.

As a result, in the optical pickup actuator of the present invention, the occupied space occupied at the vertical height is significantly reduced as compared with the prior art, thereby enabling miniaturization. In addition, the optical pickup actuator of the present invention can maximize the damping effect by placing the damper in the central portion where the displacement of the wire spring is large.

In addition, since the optical pickup actuator of the present invention does not need a conventional frame, the optical pickup actuator serves as a conventional frame only by the lens holder, thereby reducing manufacturing cost and manufacturing process due to the effect of component reduction.

As described above, the optical pickup actuator of the present invention has an advantage of maximizing damping characteristics and realizing miniaturization.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (3)

An actuator comprising a movable part and a fixed part, wherein the movable part includes a spring means having elastic force, a lens holder having the spring means positioned on its side wall and a protrusion formed on one side of the side wall, and a damping means positioned on the side wall. Optical pickup actuator, characterized in that provided. The optical pickup actuator of claim 1, wherein the damping means is located at a central portion of the spring means. The optical pickup actuator of claim 1, wherein the damping means is injected and cured from above at the protruding portion of the lens holder.