JPH05334684A - Optical pickup - Google Patents

Abstract

PURPOSE:To provide an optical pickup capable of simplifying skew adjusting work with simple constitution in the optical pickup of an optical disk recording and reproducing device. CONSTITUTION:The bottom of a skew base 44 is formed in circular arc shape. The bottom of the skew base 44 is held with an optical pickup base 42 in such a way that it can be rocked freely by abutting on a skew base abutting part 42A. The skew base 44 is held at a prescribed position in such state.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup for an optical disc recording / reproducing apparatus.

[0001]

2. Description of the Related Art Conventionally, in an optical disk recording / reproducing apparatus, a light beam is intermittently emitted from a laser diode,
By irradiating this optical beam to an optical disc to which a predetermined modulating magnetic field is applied, the thermomagnetic recording method is applied to record desired information.

Therefore, as shown in FIG. 3, in the optical pickup 1, the inclination of the objective lens 2 is adjusted at the time of assembly so that the light beam L1 is vertically incident on the optical disk 2 (hereinafter, this adjustment is referred to as skew adjustment). This means that the light beam L1 can be condensed on the optical disk 2 in a predetermined spot shape.

As a result, the optical pickup 1 holds an optical system such as a laser diode on a predetermined base 6, bends the light beam L1 of the laser diode by the mirror 8 and guides it to the objective lens 4. This allows the optical pickup 1
Focuses the light beam L1 on the information recording surface of the optical disc 2 via the objective lens 4.

Here, in the optical pickup 1, the laser diode and the like are arranged on the base 6, whereas the objective lens 4 and the mirror 8 are mounted on the base 6 via the skew base 10.

The skew base 10 holds the objective lens 4 via a predetermined actuator 12, and the bottom surface of the skew base 10 is processed into a hemispherical shape. Corresponding to the skew base 10, a circular through hole 14 is formed in the base 6, and the through hole 14 holds the hemispherical bottom surface of the skew base 10.

As a result, the skew base 10 has the arrow a.
As shown by b and b, the skew base 10 can be tilted in the incident direction of the light beam L1, and the objective lens 4 can be tilted in the direction indicated by the arrow c. The objective lens 4 can be tilted in the direction indicated by d. Therefore, in the optical pickup 1, the skew base 10 can be tilted in desired directions to adjust the tilt of the objective lens 4 in each direction.

[0007]

However, this type of optical pickup has a problem that the processing of the bottom surface of the skew base 10 is complicated.

That is, in this type of optical pickup, it is necessary to adjust the tilt with high accuracy, and for this purpose, the bottom surface of the skew base 10 must be accurately formed into a spherical shape.

However, it is generally very difficult to form a spherical surface with high precision as compared with the processing of other arcs, flat surfaces, etc.
In addition, the inspection after processing becomes complicated. Further, in the optical pickup 1, since the tilt of the objective lens 4 can be adjusted in each direction, there is a drawback that it is difficult to adjust in only one direction, and the skew adjustment is complicated accordingly.
There was also the problem of taking time.

The present invention has been made in view of the above problems, and an object thereof is to provide an optical pickup having a simple structure and capable of simplifying skew adjustment.

[0011]

According to the present invention, there is provided a skew for mounting an objective lens in an optical pickup for irradiating an optical disc with a light beam emitted from a laser light source through the objective lens. The optical pickup has a base and an optical pickup base on which the laser light source and the skew base are mounted. The skew base has an arc-shaped bottom, and the optical pickup base is in contact with the arc-shaped bottom of the skew base. It has a skew base abutting part that holds the bottom part in a slidable manner, and a skew base positioning mechanism that holds the skew base in a predetermined position.By tilting the bottom part of the skew base, the entire skew base is tilted and the objective is tilted. This is achieved by adjusting the tilt of the lens and holding it in place.

Further, in the invention of claim 2, the skew base is formed by bending the plate member in a U-shaped cross section so that the side plates extend substantially parallel to both sides from the back plate portion. Is mounted on this back plate portion, and the end of the side plate is formed in an arc shape.

Further, in the invention of claim 3, the skew base contact portion is formed of a rectangular through hole having an inner surface formed in a V shape.

Further, in the invention of claim 4, the skew base positioning mechanism is provided with a biasing means for sliding the bottom portion of the skew base in one direction, and the skew base sandwiches the arc shaped bottom portion therebetween. With a screw hole in the back plate part on the side opposite to the leaf spring, the skew base positioning mechanism is
A screw penetrating the pickup base is screwed into a screw hole of the skew base, and the skew base is biased in a direction opposite to the sliding direction by the biasing means, so that the skew base is held at a predetermined position. ..

Further, in the fifth aspect of the invention, the skew base is arranged so that the principal point of the objective lens is arranged on a straight line formed by connecting the centers of arc-shaped curved surfaces between both side plates. It

Further, in the invention of claim 6, the skew base is configured to hold the objective lens so that the objective lens can be tilted in a direction orthogonal to the tilt adjustment direction.

[0017]

According to the above-mentioned structure, the bottom of the skew base is formed in an arc shape, and the arc base of the skew base is brought into contact with the skew base abutting portion so as to be slid and held at a predetermined position. As a result, the skew adjusting mechanism can be formed by a simple working operation of forming the bottom portion of the skew base into an arc shape, and the skew can be surely adjusted in only one direction.

Further, the skew base can be easily formed by forming the skew base by bending the plate member into a U-shaped cross section.

Further, by forming the skew base contact portion by the rectangular through hole having the V-shaped inner surface, the skew adjusting mechanism can be formed with a simple structure.

Further, the skew base positioning mechanism can be easily formed by urging the skew base in one direction by urging means such as a leaf spring and urging it in the opposite direction with a screw screwed into the skew base. The skew base tilt can be adjusted simply by turning the screw.

Further, by disposing the principal point of the objective lens on the straight line formed by connecting the centers of the arc-shaped curved surfaces between the both side plates, the distance to the optical disk is kept constant even if the objective lens is tilted. By adjusting the tilt accordingly, the distance adjustment to the optical disk can be omitted again, and by holding the objective lens on the skew base so that the objective lens can be tilted in a direction orthogonal to the direction of this tilt adjustment. The skew can be adjusted in the desired direction.

[0022]

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 given, but the scope of the present invention is, unless otherwise stated in the following description, limiting the present invention.
These modes are not limited.

FIG. 1 is an exploded perspective view showing an embodiment of the optical pickup according to the present invention.

In the figure, the optical pickup 30 is such that a collimator lens and the like are housed in an optical base 32 made of aluminum die cast, and subsequently a laser diode 36 and a photodetector 38 mounted on a flexible wiring board 34 are incorporated in this optical base 32. In this way, the optical block 40 is integrally formed in advance, and then the optical block 40 is incorporated into the base 42.

Further, in the optical pickup 30, after the biaxial actuator 46, the objective lens 48 and the like are incorporated in the biaxial actuator base 44, the entire body is covered with the cover 50 to form the biaxial actuator portion 52. After integrally forming the shaft actuator portion 52, the screw 5
4 by using this biaxial actuator unit 52
It is designed to be fixed to.

As described above, the optical pickup 30 can be easily assembled by integrally forming the optical block 40 and the biaxial actuator portion 52 individually.

The biaxial actuator base 44 is
It is formed by punching a plate material and then bending it into a U-shaped cross section. That is, the biaxial actuator base 44
Is equipped with a biaxial actuator 46 on the back plate portion, and both side plates are formed in parallel with the optical axis of the light beam by bending the back plate portion at right angles to the direction of the base 42. As shown in FIG. The side plate is formed in an arc shape.

With respect to the biaxial actuator base 44, a rectangular through hole 42A having an inner wall surface formed in a V-shaped cross section is formed in the base 42, and 2 holes are formed on the inner wall surface of the V-shaped cross section. The arcuate outer periphery of the shaft actuator base 44 contacts.

Further, the biaxial actuator section base 44
Is bent so that the back plate portion on the optical block 40 side protrudes upward, and the base 42 presses the protruding portion 44B from above with the leaf spring 56.

The biaxial actuator base 44
Is a screw hole 44C in the back plate portion on the side opposite to the protruding portion 44B.
Is formed, and the screw 54 penetrating the base 42 is screwed into the screw hole 44C.

As a result, the biaxial actuator base 4
4, the leaf spring 56 biases the arcuate outer periphery of the side plate against the inner wall surface of the through hole 42A, so that the screw 54 is tightened to move the biaxial actuator portion base 44 as indicated by the arrow e. When biased, the leaf spring 56 can be bent and the whole can be tilted.

On the other hand, by loosening the screw 54, the biaxial actuator portion base 44 can be biased by the leaf spring 56 and tilted in the opposite direction, which facilitates the adjustment of the screw 54. As shown by the arrow f, the tilt can be adjusted in the incident direction of the optical pickup L1.

Therefore, the biaxial actuator 46 on the biaxial actuator portion base 44 can adjust the tilt of the objective lens 48 in a direction orthogonal to the tilt adjusting direction of the objective lens 48 by the screw 54.

As a result, in the optical pickup 30, the tilt can be individually adjusted in the incident direction of the light beam L1 and in the direction orthogonal to this direction, whereby the skew adjustment can be simplified. ..

Further, at this time, the skew adjusting mechanism can be simplified by pressing the arcuately processed biaxial actuator portion base 44 against the inner wall surface of the through hole 42A to adjust the inclination in one direction. The biaxial actuator base 44 can be easily formed to simplify the overall configuration.

In particular, when a plate-shaped member is processed into, unlike a spherical shape, it can be easily processed with high accuracy. Also, inspection after processing is easy. Therefore, the two-axis actuator base 44
By forming the side plate of (1) in an arc shape, the assembling work can be simplified accordingly.

Further, as in this embodiment, the plate material is punched and then bent to form the biaxial actuator base 44, whereby the biaxial actuator base 44 can be easily formed. The assembly time of the entire spectral pickup can be shortened.

The biaxial actuator base 44 is
The tilt of the entire biaxial actuator 46 can be adjusted in a direction orthogonal to the tilt adjustment direction, and thus, in the optical pickup 30, skew adjustment can be performed independently in the directions orthogonal to each other. ..

Further, in the biaxial actuator base 44, the arcuate curvature is set so that the principal point of the objective lens 48 is located on a straight line connecting the arcuate centers of both side plates.

As a result, the biaxial actuator base 4
In No. 4, the distance from the objective lens 48 to the optical disk 2 can be maintained at a constant value even when the screw 54 is adjusted to adjust the inclination of the objective lens 48, and thus the adjustment work can be further simplified.

In the above embodiment, the case where the plate material is processed to form the biaxial actuator portion base has been described, but the present invention is not limited to this, and the biaxial actuator portion base is formed by die casting, for example. May be. Further, in the above-described embodiment, the case where the optical block is assembled as a separate body has been described, but the present invention is not limited to this, and may be integrally assembled with the base 42.

[0042]

As described above, according to the present invention, the structure of the skew adjusting mechanism can be simplified and the skew adjusting work can be facilitated.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of an optical pickup of the present invention.

FIG. 2 is a schematic sectional view showing a relationship between an optical block and a biaxial actuator section.

FIG. 3 is a schematic cross-sectional view showing the relationship between a conventional optical block and a biaxial actuator section.

[Explanation of symbols]

 1, 30 Optical pickup 2, 42 Base 4, 40 Optical block 6, 52 2-axis actuator section 10 Laser diode 12, 13 Grating 14, 20 Collimating lens 26 Mirror 28 Objective lens 32 Optical base 44 2-axis actuator section base

Claims (6)

[Claims] 1. An optical pickup for irradiating an optical disc with a light beam emitted from a laser light source through an objective lens, comprising: a skew base on which the objective lens is mounted; and an optical pickup base on which the laser light source and the skew base are mounted. The skew base has a bottom portion formed in an arc shape, and the optical pickup base is in contact with the arc shape bottom portion, and a skew base contact portion for holding the bottom portion in a slidable manner and the skew base. A skew base positioning mechanism for holding the base at a predetermined position, and by tilting the bottom of the skew base, tilting the entire skew base to adjust the tilt of the objective lens and holding it at a predetermined position. An optical pickup characterized by. 2. The skew base is formed by bending a plate member in a U-shaped cross section so that side plates extend substantially parallel to both sides from the back plate portion, and the objective lens is mounted on the back plate portion. The optical pickup according to claim 1, wherein the tip of the side plate is formed in the arc shape. 3. The light according to claim 1, wherein the skew base contact portion is a rectangular through hole having an inner surface formed in a V shape. pick up. 4. The skew base positioning mechanism includes an urging means for sliding the bottom portion of the skew base in one direction, and the skew base is opposite to the urging means with the bottom portion having the arc shape interposed therebetween. Has a screw hole in the back plate portion of the side, the skew base positioning mechanism, by screwing a screw penetrating the pickup base into the screw hole, in the direction opposite to the sliding direction by the biasing means, The optical pickup according to claim 1, wherein the skew base is held at a predetermined position by urging the base. 5. The skew base is characterized in that the principal point of the objective lens is arranged on a straight line formed by connecting the centers of the arcuate curved surfaces of the side plate tips between both side plates thereof. Item 2. The optical pickup described in any one of Items 2 to 4. 6. The skew base holds the objective lens so that the objective lens can be tilted in a direction orthogonal to a tilt adjustment direction, according to any one of claims 2 to 5. Optical pickup described in.