JPH0836758A - Optical pickup - Google Patents

Abstract

PURPOSE:To facilitate the assembling and to reduce the size and the weight by providing a holder for holding a biaxial actuator and a light receiving and emitting unit by a yoke member and a guide for radially guiding an information recording medium. CONSTITUTION:The optical pickup comprises a biaxial actuator 34 for magnetically driving an objective lens 56 disposed corresponding to an information recording medium in focusing and tracking directions, and a light receiving and emitting unit 42 for emitting a laser light toward the medium via the lens 56 and receiving the returned light from the medium. The pickup also comprises a yoke member 32 made of a magnetic material to form the magnetic circuit of the actuator 34. The member 32 is performed by a pickup 30 having a holder 41 for holding the actuator 34 and a light receiving and emitting unit 38, and a guide 48 for radially guiding the medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing apparatus for an optical disc (information recording medium) such as a compact disc (CD) or a magneto-optical disc (eg MD), or an optical pickup used in the reproducing apparatus. is there.

[0002]

2. Description of the Related Art An optical pickup of this type is arranged in a drive unit portion of an optical disk device shown in FIG. In FIG. 3, the optical pickup 1 has an objective lens 2. The optical pickup 1 is driven by the feed motor 3 to drive the optical disc D via the gear mechanism 4.
The guide shaft 60 can move along the radial direction S (inner and outer peripheral direction). A turntable 5 is arranged near the optical pickup 1. The turntable 5 has an optical disc D such as a compact disc.
Is set to be removable. The optical disk D can be rotated together with the turntable 5 by driving the spindle motor 6. These turntables 5
The gear mechanism unit 4, the feed motor 3, the spindle motor 6 and the like are set in the chassis 7.

FIG. 4 shows the structure of a conventional optical pickup. The optical pickup 1 includes a biaxial actuator section 10 and a guide section 12. The biaxial actuator section 10 has a biaxial cover 11, a guide section 12, an adjusting plate 13, and a yoke 14. The guide portion 12 has a rack 15, a guide hole 16, a guide groove 17, and a laser emitting / receiving element (laser coupler) 18.

The biaxial actuator section 10 includes a tracking coil 19 for moving the objective lens 2 in the tracking direction TRK and an objective lens 2 in the focusing direction FC.
It has a focus coil 20 for moving to S. The biaxial actuator unit 10 can move the objective lens 2 along a focus direction FCS (a direction toward and away from the optical disc D) and a tracking direction TRK (inner and outer peripheral directions of the optical disc D) via a hinge.
In this way, by performing focus movement and tracking movement of the objective lens 2 by magnetic driving force, the laser light from the laser light source of the laser light emitting / receiving element 18 is
By focusing on the signal surface of the optical disc D, the laser light can be accurately applied along the recording track. A magnet 15 is provided on the yoke 14 of the biaxial actuator unit 10. The yoke 14 is a yoke for forming a magnetic circuit of the tracking coil 19 and the focus coil 20. The guide shaft 60 of FIG. 3 is fitted in the guide hole 16, and the guide groove 17 is fitted in another guide member. As a result, the guide section 12 guides the optical pickup 1 in the inner and outer peripheral directions of the optical disc D by the guide groove 17 and the guide hole 16.

[0005]

However, in such a conventional optical pickup structure, since the biaxial actuator section 10 and the guide section 12 are separate bodies, the biaxial actuator section 10 and the guide section 12 are separate. Requires a fastening part to fasten the device with high accuracy, the parts shape is complicated, the size of the optical pickup is very large, and the number of parts is large. Therefore, it is an obstacle to cost reduction of the optical pickup.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an optical pickup in which the number of parts is reduced, the assembling is easy, the size and weight can be reduced, and the cost can be easily reduced. I am trying.

[0007]

According to the present invention, a biaxial actuator for magnetically driving an objective lens arranged in correspondence with an information recording medium in a focus direction and a tracking direction is provided. And a light emitting / receiving unit for irradiating the information recording medium with laser light through the objective lens and receiving return light from the information recording medium, and a magnetic material for forming a magnetic circuit of the biaxial actuator. And a holding portion for holding the biaxial actuator and holding the light emitting / receiving portion, and a guide portion for guiding the information recording medium in the radial direction. This is achieved by an optical pickup having a.

In the present invention, preferably, the holding portion is integrated with an actuator holding area for holding the biaxial actuator and a light emitting / receiving portion holding area for holding the light emitting / receiving portion. In the present invention, preferably, the light emitting / receiving unit is a laser coupler having a laser light source and a light receiving unit for receiving return light. In the present invention, preferably, the actuator holding region is arranged in parallel with the light emitting / receiving unit holding region, and the light emitting / receiving unit is located at a position corresponding to the objective lens of the biaxial actuator. In the present invention, preferably, the holding portion is provided with feeding means for feeding the yoke member in the radial direction of the information recording medium.

[0009]

According to the above construction, the yoke member has the holding portion for holding the shaft actuator and the light emitting / receiving portion, and the guide portion for guiding in the radial direction of the information recording medium. The number of parts can be reduced. The holding part preferably has an actuator holding area and a light emitting / receiving part holding area integrated with each other, and the actuator holding area is preferably arranged in parallel with the light receiving / emitting part holding area, and is preferably a biaxial actuator objective. It is in the position corresponding to the lens. As a result, the number of parts can be reduced, and the return light from the information recording medium can be directly guided to the light emitting / receiving unit through the objective lens. The number of parts can be further reduced by providing the holding portion of the yoke member with the feeding means for feeding the yoke member in the radial direction of the information recording medium.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The examples described below are
Since it is a preferred specific example of the present invention, various technically preferable limitations are attached, but the scope of the present invention is, unless otherwise stated to limit the present invention, in the following description.
It is not limited to these modes.

FIG. 1 is a perspective view showing a preferred embodiment of the optical pickup of the present invention. The optical pickup of FIG. 1 is used in an optical disc device for reproducing recorded information on an optical disc as an information recording medium, for example, a compact disc. In FIG. 1, the optical pickup 30 is arranged facing the optical disc D. The optical pickup 30 generally includes a yoke member 32, a biaxial actuator 34, and a biaxial cover 36.
Etc.

The yoke member 32 is formed by bending a plate made of a magnetic material, for example, a metal magnetic material, and has a holding portion 41. The holding portion 41 of the yoke member 32 includes a biaxial actuator holding area 40 for holding the biaxial actuator 34, a light emitting / receiving element holding area 42 for holding a laser emitting / receiving element (laser coupler) 38, and It has a connecting portion 44. The yoke member 32 can be made of a magnetic material, for example, an iron-based material.

The yoke member 32 has a guide member 48 having a guide hole 46, a rack 50 and a guide claw 52. The guide member 48, the rack 50, and the guide claw 52 are attached to the yoke member 32, preferably by outsert molding. Guide member 4
8, the rack 50 and the guide claws 52 are the yoke members 32.
, For example plastic, preferably ABS
(Acrylonitrile-butadiene-styrene) and POM
(Polyacetal) or the like is almost outsert-molded. This plastic outsert-molding is performed with the yoke member in a flat state, and then the yoke member is bent to form a substantially cross-section U as shown in FIG. Alternatively, the yoke member 32 having a J-shape is formed.

A guide shaft 60 on the chassis side is inserted into the hole 46 of the guide member 48. The guide plate 63 on the chassis side is fitted into the guide claw 52. The guide shaft 60 and the guide plate 63 are the same as those set for the conventional chassis 7 shown in FIG. The guide shaft 60 and the guide plate 63 are arranged parallel to the S direction, which is the inner and outer peripheral direction of the optical disc D. The yoke member 32 includes the guide shaft 60 and the guide plate 6.
3 can guide in the direction of arrow S. The outsert rack 50 is adapted to engage with the gear of the gear mechanism section 4 shown in FIG. As a result, by driving the feed motor 3 shown in FIG.
It is possible to move and position in the direction of arrow S via the guide plate 63.

Next, the biaxial actuator 34 is a hinge type biaxial actuator in the illustrated example, and the movable part 7
7, fixing portion 94, hinge 50, tracking coil 5
2, a focus coil 54, an objective lens 56 and the like. On the yoke member 32, four yoke plates 70, 72, 74 and 76 are bent and formed parallel to each other in the direction of the optical disc D. Out of these four yoke plates 70, 72, 74 and 76, the two outer yoke plates 7
The driving magnets 80 and 80 are respectively denoted by 0 and 76.
Has been fixed. Fixed part 9 of biaxial actuator 34
4 is fixed to the yoke member 32 via the adjusting plate 90 and the pin 92. Thereby, the tracking coil 5 of the biaxial actuator 34
2. The focus coil 54 includes the yoke plates 70,
72, 74, 76.

By energizing the tracking coil 52, the yoke plates 70, 72, 74 and 76 form a magnetic circuit, and the objective lens 56 can be moved along the tracking direction TRK. Also focus coil 5
By energizing 4, the yoke plates 70, 72, 74,
The objective lens 56 can be moved in the focus direction FCS by a magnetic driving force via the lens 76.

In this way, the shape of the yoke member 32 has a characteristic, and in particular, the biaxial actuator holding region 40 and the light emitting / receiving element holding region 42 are integrated. Moreover, the light emitting / receiving element holding region 42 extends to a position directly below the objective lens 56 and is formed parallel to the biaxial actuator holding region 40. As a result, by disposing the laser light emitting / receiving element 38 in the light receiving / emitting element holding area 42, the laser light emitting / receiving element 38 is moved to the objective lens 5
The optical disc D can be easily placed by optically facing 6
The return light from can be easily guided to the light receiving portion of the laser light emitting / light receiving element 38. The laser light emitting / receiving element 38 can be directly fixed to the surface of the light emitting / receiving element holding region 42 by an adhesive or a screw, or by an adhesive or a screw via a pedestal such as a wiring board. It can also be fixed. In the above-mentioned embodiment, the number of parts constituting the optical pickup is reduced and the structure is simplified. As a result, the material cost is reduced, the number of assembly steps is small, and the size and weight can be reduced.

FIG. 2 shows a laser emitting / receiving element 3
8 is an example. A semiconductor element 124 and a micro prism 126 are arranged on the substrate 122. On the substrate 122, photodetector groups PD1 and PD2 as laser light receiving elements are arranged.

A laser diode chip 130 as a laser light emitting element is arranged on the semiconductor element 124. Laser light L from the laser diode chip 130
Is focused on the information recording surface of the optical disc D via the objective lens 56 of FIG. Photo detector group PD1, P
D2 has a predetermined pattern, and a focus error signal, a tracking error signal, and a reproduction signal can be obtained by returning the laser light L from an optical disc such as a compact disc. Laser diode chip 130
A photodiode 140 for monitoring the laser light is provided behind.

The present invention is not limited to the above embodiment. In the above embodiment, the guide member 48, the rack 50,
The guide claw 52 is formed on the yoke member 32 by outsert molding. However, the guide member 48, the rack 50, and the guide claw 52 can be formed directly from the yoke member 32 without being limited thereto. In the above-described embodiment, the tracking coil 52 and the focus coil 54 are arranged on the biaxial actuator 34 side, and the magnet 80 is arranged on the yoke member 32 side. However, not limited to this, the tracking coil 52 and the focus coil 54 are arranged on the yoke member 32 side,
It is also possible to arrange the magnet 80 on the biaxial actuator 34 side. In the embodiment described above, the optical disc D
Although an example of a compact disc is given as an example, the optical pickup of the present invention can be applied to, for example, a CD-ROM or the like in addition to the compact disc.
It can also be applied to a recording / reproducing device for a magneto-optical disk such as an MO or MD, or a reproducing device.

[0021]

As described above, according to the present invention, the number of parts is reduced, the assembling is easy, the size and weight are reduced, and the cost is easily reduced.

[Brief description of drawings]

FIG. 1 is an exploded view showing an optical pickup for an optical disc of the present invention.

FIG. 2 is a diagram showing an example of a laser emitting / receiving element of FIG.

FIG. 3 is a perspective view showing a drive unit portion including a conventional optical pickup.

FIG. 4 is an exploded perspective view of the conventional optical pickup of FIG.

[Explanation of symbols]

30 optical pickup 32 yoke member 34 2-axis actuator 40 2-axis actuator holding area 41 holding section 42 laser emission / light receiving element holding area (light emitting / receiving element holding area) 48 guide member (guide section) 50 rack (feeding means) 52 guide claw (Guide part) 52 Tracking coil 54 Focus coil 70, 72, 74, 76 Yoke plate 80 Magnet

Claims (5)

[Claims] 1. A biaxial actuator for magnetically driving an objective lens arranged corresponding to an information recording medium in a focus direction and a tracking direction, and a laser beam to the information recording medium via the objective lens. And a yoke member made of a magnetic material for constituting a magnetic circuit of the biaxial actuator, the yoke member comprising: a light emitting / receiving unit for irradiating and receiving return light from the information recording medium; An optical pickup comprising: a holding portion for holding a biaxial actuator and holding the light emitting / receiving portion; and a guide portion for guiding the information recording medium in a radial direction. 2. The optical pickup according to claim 1, wherein the holding portion is integrated with an actuator holding area for holding the biaxial actuator and a light emitting / receiving portion holding area for holding the light emitting / receiving portion. . 3. The laser receiving and emitting section is a laser coupler having a laser light source and a light receiving section for receiving return light.
Alternatively, the optical pickup according to claim 2. 4. The actuator holding area is arranged in parallel with the light emitting / receiving section holding area, and the light emitting / receiving section is located at a position corresponding to an objective lens of the biaxial actuator. Optical pickup. 5. The optical pickup according to claim 1, wherein the holding unit includes a feeding unit that feeds the yoke member in a radial direction of the information recording medium.