KR910002029Y1 - Operating apparatus of objective lens for lazer pick-up unit - Google Patents

Abstract

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Description

Objective Lens Drive for Laser Pickup

1 is an exploded perspective view of the present invention.

2 is a cross-sectional view of the present invention.

3 is a cross-sectional view of the main part optical axis parallel adjustment of the present invention.

4 is a plan view of the present invention.

* Explanation of symbols for main parts of the drawings

1 housing cover 2 shaft fixing plate

3: groove 4: bolt

6: incident light path 11: damper mounting body

14 yoke 15: magnet

16: inner wall 17: bobbin

19, 19 ': Magnet insertion hole

The present invention relates to an objective lens driving apparatus for driving an objective lens in a laser pickup for reading information contained in a compact disc.

The laser pickup is to receive information reflected by irradiating laser light onto a compact disc and read information. The laser light is oscillated and collected by an optical system and irradiated onto the compact disc through an objective lens.

Here, in order to accurately read the information, the focus of the laser beam must be correctly aligned on the compact disc, and thus an objective lens driver for this purpose is required.

The configuration for driving the objective lens is composed of a bobbin body for moving the objective lens up, down, left, and right, a coil wound around the bobbin outer circumference and generating a magnetic force in the inner circumference or outer circumference of the bobbin body.

In the objective lens driver, the magnet is located inside or outside the bobbin.

The inner magnetic shape located inside has an advantage of miniaturization. However, since the leakage magnetic flux is structurally large, the magnetic flux density of the effective space is low. Therefore, crosstalk and higher resonance occur.

To compensate for this, a magnet having a large coefficient of permeability should be used, and the yoke used here has to be separated up and down, so that the manufacturing process is difficult and has to be assembled several times.

In addition, the outer magnet shape in which the magnet is located on the outside is easy to manufacture parts, but it is not easy to make it small. In addition, the magnet should have a high coercive force to obtain a desired driving force.

On the other hand, unlike the above method, a pickup in which the bobbin is integrally fixed with the optical system has been proposed.

This one-piece type has the advantage that the yoke is very simple and easy to assemble, but the parallelism of the objective lens cannot be adjusted. Therefore, there is no way to improve the quality by correcting the error after assembly.

It is an object of the present invention to provide an objective lens driving apparatus for laser pickup, which is capable of correcting an optical axis center coincidence in an integrated structure that is easy to assemble and produce in order to solve the above drawbacks.

Accordingly, the present invention is characterized in that the magnetic flux is prevented by surrounding the outer periphery of the bobbin with a yoke, and the optical system and the objective lens driving unit are detached from each other and attached or rotated.

Hereinafter, the present invention will be described according to a preferred embodiment based on the accompanying drawings.

FIG. 1 is an exploded perspective view showing the objective lens driving device of the present invention, and FIG. 2 is a coupling cross-sectional view, and (1) shows a housing cover to which an optical system is attached.

In the housing gerber 1, a groove 3 into which the shaft fixing plate 2 is inserted is formed in a circular shape, and the shaft fixing plate 2 is screwed by the bolt 4.

At this time, the shaft fixing plate 2 is supported by the spring 5 to loosen and tighten the bolt 4, the parallel between the shaft fixing plate 2 and the groove 3 is adjusted.

The shaft retaining plate (2) is It is shaped to prevent the objective lens incident light path 6 drilled in the housing cover 1, and a hole 8 into which the shaft 7 is inserted is drilled in the center of the arc. A groove 9 having a larger diameter is formed above the groove 3, and a stepped cross section is formed in the groove 9. A damper mounting plate 11 to which the damper 10 is mounted is provided. The damper mounting plate 11 is formed with a notch 12 for smooth straightening of the beam incident through the objective lens incident light path 6.

In addition, the yoke fixing portions 13 and 13 'protrude from the outer circumferential upper portion of the groove 9 so that the yokes 14 and 14' are detachably installed by coupling means such as screws.

York 14, 14 'is " &Quot; The inner wall 16 is formed in a magnetic cross section, and the inner wall 16 to which the magnets 15 and 15 'are attached is flat, and the outer wall 16' is formed of an outer-shaped yoke, which is formed as an arcuate surface. In the bobbin 17 wound around the outer periphery, the bush 18 into which the shaft 7 is inserted is projected downward, and the magnet insertion holes 19 and 19 'are drilled.

Therefore, when the shaft 7 is inserted into the bush 18, as shown in FIG. 2, the inner wall 16 of the yoke 14, 14 'and the magnets 15, 15' attached thereto are magnets. It is located in the insertion holes 19 and 19 ', and is located in the outer wall 16' at the outer periphery of the bobbin 17. When the fixing screw 20 of the damper mounting plate 11 for mounting the damper 10 connected to the bobbin 17 is screwed through the yoke fixing portion 13 ', the position adjustment of the bobbin 17 is completed. It is configured to be fixed. In the drawings, reference numeral 21 denotes an objective lens, and 22 denotes a balance weight.

The present invention configured as described above has the inner wall 16 and the magnets 15 and 15 'of the yokes 14 and 14' inserted into the magnet insertion holes 19 and 19 'of the bobbin 17 together. As a result, the objective driving unit can be miniaturized, and the magnetic yoke type magnetic circuit can eliminate the upper yoke required for the magnetic type. The effect of preventing the leakage of magnetic flux is increased, thereby increasing the efficiency of the magnetic circuit, thereby fundamentally eliminating crosstalk and high-order retardation.

In addition, the present invention, as shown in Figure 3, the shaft fixing plate (2) is screwed to the front end of the bolt (4) through the housing cover (1) and is elastically supported by the spring (5) When the bolt 4 is loosened or tightened, the shaft fixing plate 2 is moved up and down.

The high and high motion of the shaft fixing plate 2 is the result of moving the bobbin (17) associated with the installation and eventually performs a function of adjusting the parallelism of the objective lens (21). Then, the optical axis adjustment for matching the center of the beam center of the optical system and the center of the objective lens 21 rotates the damper mounting plate 11 inserted into the groove 9 by a separate jig, the objective lens 21 of the bobbin 17. And the center of the objective lens incident light path 6 shown in FIG.

When the optical axis adjustment is completed, the damper mounting plate 11 is fixed with the fixing screw 20 to suppress the rotation of the bobbin 17, thereby preventing the optical axis from being deformed.

As described above, the present invention can simplify the structure of the yoke by integrally combining the objective lens driving device and the optical housing, thereby reducing the cost, enabling the miniaturization of the magnet, and easily adjusting the optical axis. It can work.

Claims (2)

A bolt 4 having a small diameter groove 3 interposed inside the optical housing cover 1 having the groove 9 engraved in a step shape and the groove 3 that has been electrically interposed therebetween. The shaft fixing plate 2 coupled to the optical system housing cover 1, which is coupled by the damper mounting body 11, which is accommodated in the groove 9, and fixed by the side fixing screw 20, and the inner side thereof. And a pair of cross-sections arranged on the outer periphery of the bobbin 17 and a pair of magnet insertion holes 19 and 19 'symmetrically drilled through. "The yoke 14 is made of a magnetic yoke 14, and the yoke 14 is a magnet insertion hole 19 (19 ') of the bobbin 17, the inner wall 16 to which the ordinary magnet 15 is attached. Positioning inward and the outer wall (16) is defective to locate the outside of the bobbin (17) objective lens drive device for laser pickup. 2. The magnet insertion hole (19) (19 ') of the bobbin (17) according to claim 1 is a flat " "The objective lens drive device for laser pickup, characterized in that formed in a magnetic shape.