JPH10188308A - Optical head actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily assemble a yoke at the time of assemblage. SOLUTION: The yoke to be fitted to an actuator frame 5 is formed in an approximately U-shape by connecting one pair of yoke leg parts 7a and 7b facing to each other with a bottom part 7c. Then, one yoke leg part 7a out of the one pair of yoke leg parts 7a and 7b is inserted from the lower part into one of one pair of slits 5-4 formed in the bottom wall of the actuator frame 5, and is assembled to erect in the actuator frame 5.

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 for recording / reproducing information on / from an optical recording medium such as an optical disk.

[0002]

2. Description of the Related Art An example of a conventional optical head actuator will be described with reference to FIGS. 7, an optical head actuator includes a lens holder 30 for holding an objective lens 31, a focusing coil 32a and a tracking coil 32b wound around a coil bobbin provided on the lens holder 30, and an A suspension wire 34 that movably supports the damper base 33 fixedly disposed on the base 40 in the focusing direction F and the tracking direction Tr, and a pickup base that supports the damper base 33 so as to be capable of swing adjustment in the radial direction R. 3
And an actuator base 4 that supports the pickup base 35 so as to be swingably adjustable in the tangential direction Ta.
0.

In the case shown in the figure, two pairs of suspension wires 34 are provided as a whole, and a total of four suspension wires 34 are provided. By connecting the lens holder 30 and the damper base 33 on both sides of the lens holder 30, respectively. The connection is made mechanically and electrically.

A yoke having a U-shaped overall shape is attached to the pickup base 35 by connecting mutually parallel yoke legs 35a and 35b at a bottom 35g. These yoke legs 35a and 35b are disposed so as to sandwich the lens holder 30 at an interval from a horizontal direction X perpendicular to the tracking direction, and face the lens holder 30 of one of the yoke legs 35a. A magnet 36 is provided on the inner surface. The pickup base 35 further includes a rising portion 35c for fixing the damper base 33 from the X direction, a screw 35d that passes through the rising portion 35c and is screwed into a screw hole 33a provided in the damper base 33, and a pickup from below. Screw 35e penetrating the base 35 and abutting on the lower surface of the damper base 33
And a coil spring 35f (see FIG. 7) for urging the lower surface of the damper base 33 upward. Further, a tongue 35f extending outward is provided on the bottom 35g of the yoke. The tongue 35f is fixed to the pickup base 35 by screws 35h.

[0005] The actuator base 40 has a support portion 40a for the pickup base 35 so as to adjustably support the pickup base 35 in the tangential direction Ta. The actuator base 40 further includes a laser diode 40b, a beam splitter 40
c, a rising mirror 40d and a photodiode 40e. Further, the actuator base 40 is provided with a screw 4 that penetrates the actuator base 40 from below and is screwed into a screw hole provided on the lower surface of the pickup base 35.
0f, and a coil spring 40g (see FIG. 9) for urging the lower surface of the pickup base 35 upward.

A space for accommodating a gel-like vibration damping material for suppressing vibration of the plurality of suspension wires 34 is provided at both ends in the longitudinal direction of the damper base 33 which fixes one end of the plurality of suspension wires 34. Is attached. The gel cover 37 accommodates a portion near the fixing portion of the suspension wire 34, and a gel-like vibration damping material is injected into the gel cover 37.

According to the optical head actuator configured as described above, light emitted from the laser diode 40b is
After being reflected by the beam splitter 40c, it is reflected by the rising mirror 40d, and is condensed on the signal surface of an optical recording medium (not shown) via the objective lens 31. Then, the light reflected on the signal surface of the optical recording medium is reflected again by the rising mirror 40d via the objective lens 31, passes through the beam splitter 40c, and then enters the photodiode 40e. Thereby, the photodiode 40
The information recorded on the signal surface of the optical recording medium can be detected based on the output signal from e.

[0008]

The optical head actuator is assembled through the following steps. First, the lens holder 30 is assembled as shown in FIG. Next, one ends of the plurality of suspension wires 34 are attached to the lens holder 30. Subsequently, a damper base 33 is attached to the other ends of the plurality of suspension wires 34, and a gel cover 37 is attached to the damper base 33. Then, a gel-like damping material is injected into the gel cover 37. A jig such as a syringe is used for injecting the vibration damping material. Further, the assembled body assembled as described above is assembled to the pickup base 35, and this is mounted to the actuator base 40.

More specifically, the combination of the lens holder 30 and the objective lens 3
Mutually perpendicular reference lines C for defining the center position of
1 and C2 are set, and the objective lens 31 is incorporated so that the center of the objective lens 31 coincides with the intersection. On the other hand, the damper base 33 is combined with the lens holder 30 such that the center line thereof coincides with the reference line C2. Further, the damper base 33 is fixed to the pickup base 35 such that the center line of the damper base 33 coincides with a reference position set at the rising portion 35c of the pickup base 35.

However, in the above assembling process, a screw hole must be formed in the pickup base 35 and the tongue portion 35f of the yoke must be screwed with the screw 35h, and fixing with the screw 35h requires a large number of steps. There is a problem of doing.

In order to improve the positioning accuracy of each part, the dimensional accuracy of each part must be improved.
There is a problem that the dimensional error of each part directly affects the assembling accuracy.

In addition, apart from the above-mentioned problems, the tip of the syringe comes into contact with the suspension wire 34 at the time of injection of the vibration damping material, or at the time of assembling with the pickup base 35, When the suspension wire 34 comes into contact with the suspension wire 34,
However, there is also a problem that it is deformed.

An object of the present invention is to provide an optical head actuator that is effective for improving the assembly accuracy.

Another object of the present invention is to provide an actuator frame that allows the yoke to be easily assembled.

[0015]

According to the present invention, there is provided a lens holder for holding a lens for an optical pickup, and a lens holder for supporting this lens holder vertically and horizontally via a plurality of suspension wires. An optical head actuator having a fixing portion for fixing one end side of the plurality of suspension wires, the damper base being used for fixing the damper base and accommodating the lens holder. A yoke combining a magnet is mounted on the actuator frame, and an opening through which a light incident on the objective lens and a reflected light can pass through is provided on a bottom wall of the actuator frame. The yoke has a pair of yoke legs opposed to each other at the bottom. Connecting substantially has the shape of a U-shape and,
The wider yoke leg of the pair of yoke legs is assembled so as to be inserted into a pair of slits formed on the bottom wall of the actuator frame from below and stand up in the actuator frame. An optical head actuator is obtained.

According to the present invention, when one yoke leg of the yoke is inserted into one slit formed in the bottom wall of the actuator frame, the one slit is inserted into the actuator frame. An optical head actuator, wherein a positioning groove is formed so as to be inserted into the one slit while sliding the one yoke leg along the inside of a side wall of the actuator frame located near the actuator frame. Is obtained.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing an optical head actuator according to an embodiment of the present invention, FIG. 2 is a bottom view thereof, and FIG. 3 is a sectional view taken along line AA 'of FIG. Referring to FIG. 1, an optical head actuator 1 includes an actuator base 2 and an objective lens 3-1.
And a lens holder 3 having a tracking coil 3-2 and a focusing coil 3-3 (see FIG. 3), and an actuator frame 5 accommodating the lens holder 3 and the damper base 4.

Referring to FIG. 3, the optical head actuator 1 has a laser section 11 for generating a laser beam.
The laser light emitted from the laser unit 11 is applied to the beam splitter 1
The light is irradiated from 2 through an objective lens 3-1 onto an optical disk 13 which is an optical recording medium. The reflected light from the optical disk 13 enters the light receiving device 14 from the objective lens 3-1 via the beam splitter 12. That is, the light receiving device 14 receives the reflected light from the optical disc 13.

The laser section 11 and the beam splitter 12 are held on the actuator base 2. Note that the actuator base 2 is further held and fixed to the housing of the optical disk drive. A circuit board 15 is fixed to a side surface of the actuator base 2. The circuit board 15 is electrically connected to other circuit elements of the optical disk drive by a connector 16 mounted thereon.

On the lower surface of the actuator base 2, the above-mentioned light receiving device 14 is assembled. Light receiving device 14
Comprises a photodiode 14-2 mounted on an element holder 14-1. The actuator frame 5 has
A cover 17 that exposes the objective lens 3-1 and covers the remaining surface is provided.

Returning to FIG. 1, the suspension between the lens holder 3 and the damper base 4 is connected by a plurality of suspension wires 6.
Is housed in The actuator frame 5 is further provided with a pair of yokes 7, and the yoke 7 is combined with a magnet 8.

As shown in FIG. 4, the pair of yokes 7 has yoke legs 7a and 7b facing each other,
It has a substantially U-shape with the bottom 7c connecting the yoke legs 7a and 7b. One yoke leg 7a of the pair of yoke legs 7a, 7b has a wide shape. The other yoke leg 7b has a narrower shape than the one yoke leg 7a.

Further, referring to FIG. 4, the actuator frame 5 has a receiving portion for the damper base 4 at one end of a substantially box-like body formed of a resin material. The receiving portion has a support block 5-1 for fixing the damper base 4 with the screw 9. Also, the actuator frame 5
The bottom wall is provided with an opening 5a through which light incident on the objective lens 3-1 and reflected light can pass. Further, on both side walls of the substantially box-shaped body, a substantially semicircular protrusion 5-
2 and a hole 5-3 through which an injector for injecting a gel-like vibration damping material can be inserted. This hole 5-3 is used to regulate the vertical movement of the injector.
An elliptical shape is preferred. This is when the damping material is injected
This is to prevent a part of the injector from contacting and deforming the suspension wire 6. Support part 2-1
Has the same shape as that described in FIG.

The damper base 4 has a U-shape, and leg portions on both sides thereof are hollow, and a fixing portion 4-1 for fixing one end of the suspension wire 6 is provided at a rear portion thereof.

Further, on the rear wall of the damper base 4, there is provided a flexible wiring board (not shown) for soldering connection with the end of the further fixed suspension wire 6. This damper base 4 has leg-shaped portions on both sides which are connected to both side walls of the actuator base 2 and the support block 5-.
1 and is fixed with screws 9 in a state of being inserted into the space between them.

As described below, before fixing the damper base 4 to the actuator base 2, the damper base 4
Is provided with a suspension wire 6. That is, the lens holder 3 and the damper base 4 are housed and fixed in the actuator frame 5 in a state of an assembly connected by a plurality of suspension wires 6.

A method of assembling the present optical head actuator will be described. First, two sets of yokes 7 and magnets 8 are attached to the actuator frame 5. Referring to FIG. 4, this assembling is performed by connecting a pair of yoke legs 7a and 7b facing each other with a bottom portion 7c to form a substantially U-shaped two yoke legs 7a and 7b. The wider yoke leg 7 a is inserted from below into a pair of slits 5-4 formed in the bottom wall of the actuator frame 5 to rise into the actuator frame 5,
The bottom 7c of the yoke 7 is bonded to the lower surface of the actuator frame 5.

It should be noted that the narrower yoke leg 7 of the yoke 7
b rises into the actuator frame 5 through the opening 5a. Next, the magnet 8 is bonded to the wider yoke leg 7a of the yoke 7.

Further, one yoke 7 is provided with one slit 5 formed on the bottom wall of the actuator frame 5.
-4, and at this time, one slit 5-4
Is raised in one slit 5-4 while sliding along a pair of opposing positioning grooves 5-8 formed along the inside of the side wall of the actuator frame 5 located in the vicinity of.

On the other hand, the lens holder 3 is assembled while being held by the jig. Next, a plurality of suspension wires 6 are attached to the assembled lens holder 3.
Subsequently, the lens holder 3 to which the suspension wire 6 is attached is positioned in the actuator frame 5 fixed by another jig. Then, the damper base 4 is attached to the ends of the plurality of suspension wires 6 in the positioned lens holder 3. In this case, the damper base 4 is also held by another jig, and the damper base 4 is fixed to the support block 5-5 of the actuator frame 5 so that the ends of the suspension wires 6 enter the hollow portions on both sides of the damper base 4. The assembling is performed by horizontally moving toward 1. Further, the assembled damper base 4 is fixed to the support block 5-1 of the actuator frame 5 with screws 9, and the suspension wire 6 is fixed to the fixing portion 4-1 of the damper base 4. Finally, a damping material is injected into the hollow space of the damper base 4 containing the suspension wire 6. This injection is performed using an injector such as a syringe through holes 5-3 on both side walls of the actuator frame 5.

In particular, the positioning of the lens holder 3 is described in FIG.
In the actuator frame 5, an optical axis L1 that passes through a line segment S1 connecting the centers of the protrusions 5-2 on both sides of the actuator frame 5 and in which the center of the objective lens 3-1 is to be located is set in advance. Reference laser light is emitted from a laser diode LD attached to a jig (not shown) through the opening 5a from below the actuator frame 5 in accordance with the optical axis L1. A monitor camera is provided above the lens holder 3 to monitor an incident point of a reference laser beam to the objective lens 3-1. In FIG. 5, a hatched area indicates a monitor area of a monitor camera. While monitoring with the monitor camera, the laser beam for reference is incident on the center of the objective lens 3-1, that is, the lens holder 3 is held so that the optical axis L2 of the objective lens 3-1 coincides with the optical axis L1. The lens holder 3 is positioned in the actuator frame 5 by adjusting the position of the jig being adjusted.

As described above, in the present embodiment, since the lens holder 3 and the damper base 4 are assembled in a state where the lens holder 3 is positioned in the actuator frame 5, the lens holder 3 is placed in the actuator frame 5 with accuracy. Well positioned. The actuator frame 5 covers and protects the suspension wire 6 on both sides thereof. After the suspension wire 6 is attached to the lens holder 3, the suspension wire 6 is immediately accommodated in the actuator frame 5. Therefore, the suspension wire 6 is not deformed in the subsequent steps. Needless to say, the suspension wire 6 is not deformed by the injector even in the damping material injection step.

[0033]

As described above, according to the present invention, since the yoke can be easily assembled to the actuator frame without screwing, the assembling accuracy is improved.

In addition, since the actuator frame is formed with a positioning groove for guiding and positioning the yoke, the yoke can be reliably positioned.

[Brief description of the drawings]

FIG. 1 is a plan view of an optical head actuator obtained according to the present invention.

FIG. 2 is a bottom view of the optical head actuator of FIG. 1;

FIG. 3 is a longitudinal sectional view taken along line AA ′ of FIG. 1;

FIG. 4 is a perspective view of an actuator frame used in the present invention.

FIG. 5 is a plan view showing a main part of FIG. 4;

FIG. 6 is a diagram for explaining a method of positioning a lens holder with respect to an actuator frame in the present invention.

FIG. 7 is an exploded perspective view of a conventional optical head actuator.

FIG. 8 is a partial cross-sectional side view for explaining a mounting structure of a damper base in FIG. 7;

FIG. 9 is a partial cross-sectional side view for explaining a mounting structure of the pickup base in FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical head actuator 2 Actuator base 3 Lens holder 3-1 Objective lens 3-2 Tracking coil 4 Damper base 5 Actuator frame 5-4 Slit 5-8 Positioning groove 6 Suspension wire 7 Yoke 7a, 7b Yoke leg 8 Magnet

Claims (2)

[Claims] 1. A lens holder for holding a lens for an optical pickup, and a damper base for supporting the lens holder to be vertically and horizontally displaceable via a plurality of suspension wires, wherein the damper base is An optical head actuator having a fixing portion for fixing one end side of the plurality of suspension wires, comprising a substantially box-shaped actuator frame for fixing the damper base and accommodating the lens holder. A yoke combining a magnet is assembled to the actuator frame, and an opening through which incident light and reflected light to the objective lens can pass is provided on a bottom wall of the actuator frame. It has a substantially U-shape in which a pair of opposed yoke legs are connected at the bottom. The wider yoke leg of the pair of yoke legs is assembled so as to be inserted from below into a pair of slits formed in the bottom wall of the actuator frame and rise into the actuator frame. Optical head actuator. 2. The optical head actuator according to claim 1, wherein one yoke leg of the yoke is inserted into the actuator frame through one slit formed in a bottom wall of the actuator frame.
A positioning groove is formed so as to be inserted into the one slit while sliding the one yoke leg along the inside of a side wall of the actuator frame located near the one slit. Optical head actuator.