JP3473663B2 - Optical head actuator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head actuator provided in an optical disk driver, and more particularly to improvement of a lens holder that holds a pickup lens.

[0002]

2. Description of the Related Art Referring to FIGS. 8 and 9, an optical head actuator 10 of this type includes an actuator base 11
And an actuator section 12 mounted on the actuator base 11 and housed in a predetermined space together with a motor 13 for rotating / driving an optical recording medium such as a CD, which constitutes an optical pickup device.

The optical head actuator 10 includes an optical component 1 such as a beam splitter 14 and a half mirror 15.
6. A flexible circuit board 17 is provided. On the flexible circuit board 17, a laser unit 18 such as a connector, a grating and a laser diode, a photodiode 19, and an electronic component 22 such as a variable resistor 20 and a chip capacitor 21 are mounted. The flexible circuit board 17 is bent and three-dimensionally attached to the actuator base 11. The laser section 18 is attached to the support section 24 of the actuator base 11 by a pressing plate.

In the optical head actuator 10, the laser light generated by the laser diode in the laser section 18 is used for the half mirror 15 and the beam splitter 1.
4. The optical recording medium is irradiated through the objective lens or the like in the actuator unit 12, and the reflected light thereof is the objective lens,
The light is received by the photodiode 19 via the beam splitter 14, the half mirror 15, and the like.

[0005]

By the way, as shown in FIG. 10, the photodiode 19 is attached to the photodiode holder 30, and the photodiode holder 30 is fixed to the actuator base 11 by adhesion. Reference numeral 31 indicates an adhesive portion. Before this fixing, that is, at the final stage of the manufacturing process, optical adjustment is performed. In this optical adjustment, the Z-axis, that is, the optical path length is adjusted by adjusting the position of the laser diode in the optical axis direction.
This optical path length adjustment is an adjustment for equalizing the optical path lengths of the light transmitting system and the light receiving system with the optical recording medium in between. On the other hand, by sliding the photodiode holder 30 on the actuator base 11, the XY axis adjustment is performed. The X-Y axis adjustment is an adjustment for receiving the reflected light at the center of the photodiode 19.

However, in the above conventional structure, it is necessary to alternately perform the optical path length adjustment and the XY axis adjustment for the optical adjustment, which is troublesome and time-consuming. This is because the laser diode is held in a space in which a slight backlash occurs in order to facilitate mounting in the laser unit 18, and the light emitting point of the laser diode shifts when the optical path length is adjusted. by.

Therefore, an object of the present invention is to provide an optical head actuator capable of facilitating optical adjustment.

Another object of the present invention is to achieve the above object with a minimum number of parts.

[0009]

SUMMARY OF THE INVENTION The present invention provides an actuator base and an assembly surface for the actuator base.
In the optical head actuator comprising a photodiode for receiving light reflected from the optical recording medium is assembled by the child base, said element base, photodiode plate and the photo diode mounted with the photo die <br/> Hauts de consists of a photodiode base supporting the plate in cantilevered, yet an integral molded structure and said photodiode base and the photodiode plates linked in the support portion of the cantilevered, the
The photodiode base has about the same depth
Formed on the mounting surface of the actuator base as
It is housed in a recess or groove, and is bent to L shape on both sides.
Has a ridged end and is received in the recess or groove.
The photodiode so as to straddle the photodiode base.
Mounted on the mounting surface of the chute base by screwing
A cover, the end of the cover being the photo
Part of the diode base and the mounting surface adjacent to it
The cover is elastic so that the elasticity of the cover causes
It is designed to hold the ion base,
The mounting surface adjacent to a part of the diode base
While protrusions are formed at multiple locations, before corresponding to the protrusions
A hole into which the protrusion can be fitted is formed at the end of the cover.
This prevents the cover from being screwed.
It is characterized in that the rotating force is prevented from being transmitted to the element holder .

A notch or hole through which a screw can be inserted is provided at the end of the photodiode plate opposite to the supporting portion, and the photodiode base corresponding to the notch or hole is provided with the screw. Is provided, and the photodiode plate is displaced by the screw with the supporting portion as a fulcrum to finely adjust the optical path length.

Further, a fulcrum of the supporting portion is on an extension surface of a light receiving surface of the photodiode.

In addition, the photodiode base is
It is characterized in that it is attached to the actuator base such that its position can be adjusted with respect to two axes perpendicular to each other on a plane parallel to the light receiving surface of the photodiode.

[0013]

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the drawings. First, the structure of the entire optical head actuator will be described. Figure 1,
With reference to FIG. 2, this optical head actuator includes a laser section 1 that generates a laser beam. The laser light emitted from the laser unit 1 is applied from the beam splitter 2 through the objective lens 3 to the optical disc 4 which is an optical recording medium. The reflected light from the optical disc 4 enters the light receiving device 5 from the objective lens 3 through the beam splitter 2. That is,
The light receiving device 5 receives the reflected light from the optical disc 4.

The laser unit 1 and the beam splitter 2 are held by an actuator base 6. The actuator base 6 is held and fixed to the housing of the optical disk drive. A circuit board 7 is fixed to the side surface of the actuator base 6. The circuit board 7 is electrically connected to other circuit elements of the optical disk drive by the connector 7-1 mounted on the circuit board 7.

In the present embodiment, the above-mentioned light receiving device 5 is assembled on the lower surface of the actuator base 6. The light receiving device 5 includes a photodiode 5-on the element holder 5-1.
It is equipped with 2. The element holder 5-1 has a larger projected area than the photodiode 5-2, and the element holder 5-1 projects outward from the photodiode 5-2. By utilizing the portion protruding to the outside of the element holder 5-1, the light receiving device 5 is held on the actuator base 6 by using the cover 8 as described below.

Referring also to FIGS. 3 and 4, the actuator base 6 is mounted on the mounting surface 6-for mounting the light receiving device 5.
Have one. The element holder 5-1 is attached to the mounting surface 6-1.
Is formed with a groove or recess 6-2 for receiving the. The width dimension of the recess 6-2 is larger than the width dimension of the element holder 5-1 and the depth dimension is made substantially equal to or slightly shallower than the thickness dimension of the main portion of the element holder 5-1. .

The mounting surface 6-1 is further provided with the recess 6-.
Two protrusions on each side of the two sides, a total of four protrusions 6-
3 is formed. Although these projections 6-3 are formed integrally with the actuator base 6, they may be attached separately.

The cover 8 is made of a metal plate and has a main portion 8a having a central opening portion and L at both ends thereof.
It has both end portions 8b and 8c which are integrally bent and formed. Cover 8 on the actuator base 6
To attach the both ends 8 so as to straddle the recess 6-2.
b, 8c abutting on the mounting surface 6-1 and both end portions 8b, 8c
8c is fixed to the actuator base 6 with the screw 9. Both ends 8a and 8b of the cover 8 that are brought into contact with the actuator base 6 partially oppose the recess 6-2. Therefore, when the screw 9 is tightened, both end portions 8a and 8b are opposed to each other at both ends of the element holder 5-1 due to the relationship between the depth of the recess 6-2 and the thickness of the main portion of the element holder 5-1. The part is elastically pressed toward the inner bottom of the recess.
That is, the light receiving device 5 is held between the actuator base 6 and the cover 8 by the elasticity of the cover 8.

When mounting on the actuator base 6, the projections 6-3 of the actuator base 6 can be fitted into the holes 8-1 at both ends of the cover 8, thereby stopping the movement of the cover 8 and tightening the screws 9. preferable. According to this, the rotational force of the screw 9 can be prevented from being transmitted to the element holder 5-1, so that the positioning work of the light receiving device 5 in the recess 6-2 with the XY axis adjustment becomes simple. . That is, after adjusting the position of the light receiving device 5 with respect to the XY axes in the recess 6-2, the light receiving device 5 can be accurately positioned at a desired position by firmly tightening the screw 9.

Further, the cover 8 is attached to the actuator base 6, and the main portion 8a of the cover 8 is the light receiving device 5.
Will be covered from above and covered. Therefore, the light receiving device 5 is protected by the main portion 8a of the cover 8 from being applied with a force such as an impact from the outside.

The cover 8 may be fixed to the actuator base 6 by other fixing means instead of the screw 9.
Needless to say, the number of the protrusions 6-3 can be variously modified.

Next, the structure of the element holder 5-1 will be described with reference to FIGS. Photodiode 5-
2 is mounted on the element holder 5-1 as described above, the element holder 5-1 is the photodiode 5-2.
And a photodiode base 5-12 supporting the photodiode plate 5-11 in a cantilever manner. In particular, the photodiode plate 5-11 and the photodiode base 5-12 are made by integrally molding a metal material in such a shape that they are connected at one end side. At the other end of the photodiode plate 5-11, a screw 5
-13 is provided with a hole 5-11a which can be inserted therethrough, and the corresponding photodiode base 5-12 has a screw 5-1.
A screw hole (not shown) for receiving 3 is provided.
The photodiode base 5-12 is a hollow body so that the reflected light from the optical recording medium can pass therethrough.
The light enters the photodiode 5-2 from the middle and lower sides through the hollow portion of the photodiode base 5-12. Then, the Z-axis, that is, the optical path length is finely adjusted by changing the insertion depth of the screw 5-13.

Here, when the insertion depth of the screw 5-13 is changed, the connecting portion on one end side of the photodiode plate 5-11 serves as a support portion, and the other end side moves up and down with this support portion as a fulcrum. Here, it is characterized in that the fulcrum of the supporting portion is on the extension surface of the light receiving surface of the photodiode 5-2, that is, at the same height.

FIG. 7 shows the photodiode plate 5-1.
3 shows the positional deviation of the light receiving point of the photodiode 5-2 due to the positional displacement of No. As shown in the drawing, the depth of the screw 5-13 is increased to increase the depth of the photodiode plate 5-11.
When is rotated downward by an angle θ, the light receiving point of the photodiode 5-2 may be a minimum value of δ [= L (1-cos θ)]. This is because the fulcrum of the supporting portion and the light receiving surface of the photodiode 5-2 are at the same height.

[0026] The structure described above, X-Y-axis adjustment and the optical path length adjustment, the photodiode plates 5-11 and the photodiode base 5-12 and the element E with integrated <br/> holder 5-1 The optical adjustment work is easy and the number of parts is only two.

[0027]

As described above, according to the present invention, it is possible to provide an optical head actuator capable of facilitating optical adjustment with a small number of parts.

[Brief description of drawings]

FIG. 1 is a vertical sectional view for explaining an internal structure of an optical head actuator according to the present invention.

FIG. 2 is a bottom view of the optical head actuator shown in FIG.

FIG. 3 is a perspective view for explaining a holding structure of the light receiving device shown in FIG.

FIG. 4 is a cross-sectional view taken along the line AA ′ of FIG.

5 is a diagram for explaining the element holder shown in FIG. 1. FIG.

6 is a cross-sectional view of the element holder shown in FIG.

7A and 7B are schematic diagrams for explaining the action associated with the optical path length adjustment of the element holder shown in FIG.

FIG. 8 is a plan view of a conventional optical head actuator.

9 is a side view of the optical head actuator of FIG. 8 as seen from the direction of arrow B. FIG.

10 is a diagram for explaining a mounting structure of the photodiode shown in FIG.

[Explanation of symbols]

1 laser section 2 beam splitter 3 Objective lens 4 optical disks 5 Light receiving device 5-1 Element holder 5-2 Photodiode 5-11 Photodiode plate 5-12 Photodiode base 6 actuator base 8 covers

Continuation of front page (56) Reference JP-A-7-235059 (JP, A) JP-A-63-268130 (JP, A) JP-A-7-127610 (JP, A) JP-A-7-296409 (JP , A) Actual Kaihei 1-2816 (JP, U) Actual Kaihei 1-224715 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G11B 7/085 G11B 7/135

Claims (4)

(57) [Claims] 1. An optical head actuator comprising: an actuator base; and a photodiode mounted on the mounting surface of the actuator base by the element base to receive reflected light from an optical recording medium , wherein the element base is the or a photodiode plate mounted with diode and photodiode base for supporting the photodiode plates at cantilevered
The photodiode plate and the flap.
A photodiode base and integrally molded structure which is connected at the support portion of the cantilever, the photodiode base, approximately the same depth as this
Formed on the mounting surface of the actuator base to have
It is accommodated in a recessed portion or groove formed therein , and further has an end portion formed by bending it into an L shape on both sides.
The photodiode array housed in the recess or groove.
Mounting surface of the actuator base so as to straddle the base
A cover that is attached to the photodiode base by means of a screw.
Part and the assembly surface adjacent thereto.
The elasticity of the cover holds the photodiode base
And the assembly adjacent to a part of the photodiode base.
While the protrusions are formed at multiple points on the contact surface,
The protrusion can be fitted to the end of the corresponding cover.
The cover is screwed because the hole is formed.
Rotational force during transfer is not transmitted to the element holder
An optical head actuator being characterized in that the. 2. The optical head actuator according to claim 1, wherein a notch or hole through which a screw can be inserted is provided at an end portion of the photodiode plate opposite to the supporting portion, and the notch or hole is provided. An optical head characterized in that the corresponding photodiode base is provided with a screw hole for the screw, and the photodiode plate is displaced by the screw with the support portion as a fulcrum to finely adjust the optical path length. Actuator. 3. The optical head actuator according to claim 2, wherein a fulcrum of the supporting portion is on an extension surface of a light receiving surface of the photodiode. 4. The optical head actuator according to claim 3, wherein the photodiode base is attached to the actuator base such that the photodiode base is positionally adjustable with respect to two axes perpendicular to each other on a plane parallel to the light receiving surface of the photodiode. An optical head actuator characterized in that