JPH05303748A - Optical pickup device - Google Patents

Abstract

PURPOSE:To provide the optical pickup device capable of reducing the power required for inclining an object lens actuator when adjusting the inclination and decreasing the working cost CONSTITUTION:On an optical block 3, an opening section 3b is surrounded by equally spaced recessed sections 11 formed around an optical axis S. The lower parts of spheres 12 are engaged with the recessed sections 11 to rotate freely. A lower end surface 1c of the object lens actuator 1 is formed as a sphere around a principal point P of the object lens 2, which point-contacted with the sphere 12 fixed on an optical block 3 by means of a screw 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to an optical recording / reproducing apparatus such as an optical disk apparatus, a magneto-optical disk apparatus, etc., for irradiating a disk as a recording / reproducing medium with a light spot to record or reproduce information. The present invention relates to an optical pickup device.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 59-223953 discloses adjusting an objective lens, an objective lens driving device integrated with the objective lens, an optical block, and an inclination of the objective lens driving device with respect to the optical block. And an optical pickup having a convex spherical surface centered in the objective lens is formed at the bottom of the base of the objective lens driving device. A concave spherical surface that is in contact with the convex spherical surface and that has the same center as the convex spherical surface is formed on the upper surface of the block. Thus, no matter which direction the objective lens driving device is tilted, the position of the light spot projected by the objective lens and the distance between the objective lens and the disk do not change, and the tilt of the objective lens can be adjusted efficiently. You can

In a recording / reproducing apparatus to which the above optical pickup is applied, in order to write or read information accurately, it is necessary to maximize the performance of the objective lens and narrow the light spot as small as possible. Therefore, the tilt of the objective lens must be close to zero for that purpose.

[0004]

In the optical pickup having the above-mentioned structure, the inclination of the objective lens is adjusted by sliding the convex spherical surface in contact with the concave spherical surface to incline the objective lens driving device. However, since the frictional force becomes large in the surface contact state, the objective lens driving device cannot be tilted unless a large force is applied. This is
This lowers the workability of the tilt adjustment of the objective lens and makes it difficult to finely adjust the tilt of the objective lens.

Further, unless the surface roughness of each of the convex spherical surface and the concave spherical surface is made small, it becomes difficult to tilt the objective lens driving device smoothly. When each of the concave spherical surfaces is processed with high accuracy, there arises a problem that the processing process becomes complicated and the processing cost increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical pickup device capable of reducing the operating force required for tilting the objective lens actuator during tilt adjustment in order to solve the above problems and suppressing the processing cost. ..

[0007]

In order to solve the above problems, the present invention provides an objective lens actuator, and an optical block for supporting the objective lens actuator,
In an optical pickup device including means for adjusting the inclination of the objective lens actuator with respect to the optical block, a concave portion formed at a position facing the objective lens actuator of the optical block, and rotatably fitted into the concave portion. It is configured to adjust the inclination of the objective lens actuator by contacting the lower end of the objective lens actuator with the spherical body.

Further, it is provided with an objective lens, an objective lens actuator for supporting the objective lens, an optical block for supporting the objective lens actuator, and means for adjusting the inclination of the objective lens actuator with respect to the optical block. In the optical pickup device, the contact surface of the objective lens actuator with respect to the optical block is formed to be an inclined surface that comes into contact with a virtual spherical surface having a center in the objective lens. Further, a low friction layer made of a low friction material is formed on at least one of the contact surface and the contact portion of the optical block with respect to the objective lens actuator.

[0009]

According to the above means, a concave portion formed at a position facing the objective lens actuator of the optical block,
By providing three or more spheres that are rotatably fitted in the recesses and configured to bring the lower end of the objective lens actuator into contact with the spheres to adjust the inclination of the objective lens actuator, The sphere is rotated by the objective lens actuator during tilt adjustment.

Further, the contact surface of the objective lens actuator with respect to the optical block is formed so as to be an inclined surface which comes into contact with a virtual spherical surface having a center in the objective lens, so that the objective lens can be displaced during tilt adjustment. By forming a low friction layer on at least one of the contact surface or the contact portion of the optical block with respect to the objective lens actuator, the contact surface of the objective lens actuator during sliding and the contact portion of the optical block can be suppressed. The frictional drag can be reduced.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a side sectional view showing a schematic structure of an optical pickup device according to a first embodiment of the present invention.

Reference numeral 1 is an objective lens actuator for fixing the objective lens 2 and driving the objective lens 2 in a predetermined direction. Reference numeral 3 is an optical block serving as a support base of the objective lens actuator 1. The objective lens actuator 1 and the optical block. 3 is formed in a hollow structure, and is configured so that the laser beam L passes through the inside. In addition, a laser beam L is provided in the objective lens actuator 1.
An objective lens 2 for condensing light is held via a holder 4, a mechanism (not shown) for moving the objective lens 2 in a predetermined direction is arranged, and a reflection mirror for reflecting the laser beam L is provided in the optical block 3. 5 are arranged.

FIG. 2 is a perspective view showing an optical block in the first embodiment.

The optical block 3 has a laser beam L on its upper surface.
The three screw holes 3a are formed at equal intervals in the circumferential direction with respect to the optical axis S, and are equidistantly spaced with respect to the optical axis S at the outer peripheral positions of the openings 3b formed on the upper surface (120 ° intervals).
Thus, the recess 11 is formed. The lower portion of a sphere 12 having wear resistance and a certain strength or more is fitted in the recess 11.

The objective lens actuator 1 is placed on a sphere 12 fitted in the recess 11, and a stay 1a protruding in the radial direction is formed on the side surface of the objective lens actuator 1 and a screw hole is formed in the stay 1a. An insertion hole 1b is formed at an extension position of 3a.

A screw 6 is inserted into the insertion hole 1b, and the screw 6
Is screwed into the screw hole 3a of the optical block 3. At this time, the head of the screw 6 larger than the diameter of the insertion hole 1b comes into contact with the upper surface of the stay 1a, so that the objective lens actuator 1 is fixed onto the optical block 3 via the sphere 12.

The objective lens actuator 1 has a lower end surface 1
c is in contact with and fixed to the spherical body 12, and the lower end surface 1c which is a contact surface with the spherical body 12 is formed to be a spherical surface having a radius R1 with the principal point P of the objective lens 2 as the center.
The lower end surface 1c is fixed to the optical block 3 with point contact corresponding to each of the three spheres 12.
Is not in contact with.

Next, the work of adjusting the inclination of the objective lens 2 will be described.

The objective lens actuator 1 and the objective lens actuator 1 hold the objective lens actuator 1 and the objective lens actuator 1 by appropriately loosening the screws 6 other than the screw 6 arranged at the position corresponding to the inclination direction and tightening the screws 6 corresponding to the next inclination direction. The objective lens 2 thus tilted is tilted by an angle corresponding to the insertion amount of the screw 6 into the screw hole 3a. At this time, the spherical body 12 fitted in the recess 11 is rotated while being driven by the lower end surface 1c of the objective lens actuator 1 while always being in contact with the lower end surface 1c.

When the objective lens 2 is tilted at a desired angle, the loosened screw 6 is first tightened, and the head of the screw 6 is brought into contact with the upper surface of the stay 1a. As a result, the objective lens actuator 1 is fixed by the screw 6, and the objective lens 2 is also fixed in the tilt direction.

As described above, since the lower end surface 1c is formed so as to be a spherical surface having the radius R1 with the principal point P of the objective lens 2 as the center, the inclination of the objective lens 2 is tilted by tilting the objective lens actuator 1. Even if the adjustment is performed, the distance between the objective lens 2 and the disc (recording / reproducing medium not shown) and the position of the light spot do not change. Further, when the tilt is adjusted, the sphere 12 is rotated following the lower end surface 1c, so that the frictional drag force is reduced, so that the operation force required to tilt the objective lens actuator 1 becomes very small.
The tilt of the objective lens 2 can be adjusted smoothly and with high accuracy.

FIG. 3 is a perspective view showing another example of the main part in the first embodiment.

At the outer peripheral position of the opening 3b of the optical block 3, three recesses 13 which are long in the tangential direction of the opening 3b are formed at equal intervals. The lower part of the cylindrical body 14 is fitted and inserted into each of the recesses 13. Here, the cylindrical body 14 has an opening 3b.
The tangent line and the axis line are parallel to each other and are rotatable with respect to the axis line.

The objective lens actuator 1 has a lower end surface 1
The c is fixed to the optical block 3 by making point contact with the cylindrical body 14.

Also in the optical pickup device having the main part shown in FIG. 3, the inclination of the objective lens 2 is adjusted by the same method as that described with reference to FIGS. However, since the rotation direction of the columnar body 14 is limited to the direction around the axis, all the columnar body 14 are not always adjusted when adjusting the inclination.
Does not rotate following the movement of the lower end surface 1c. At this time, the frictional force generated between the cylindrical body 14 and the lower end surface 1c is larger than that when the spherical body 12 is used.
Since 14 and the lower end surface 1c are in point contact with each other, the frictional drag force can be sufficiently reduced when adjusting the inclination.
The tilt of the objective lens 2 can be adjusted smoothly and with high accuracy.

FIG. 4 is a perspective view showing another example of the main part in the first embodiment.

At the outer peripheral position of the opening 3b of the optical block 3, contact members 15 having hemispherical tip portions 15a are equidistant (12).
Three trees are planted at 0 ° intervals.

The objective lens actuator 1 has a lower end surface 1
The c is brought into point contact with the tip portion 15a of the contact member 15 and fixed on the optical block 3.

Even in the optical pickup device having the main part shown in FIG. 4, the inclination of the objective lens 2 is adjusted by the same method as that described with reference to FIGS.

During tilt adjustment, the objective lens actuator 1
Since the lower end surface 1c of the sliding member slides in a state of being in point contact with the tip portion 15a of the contact member 15, the frictional drag force generated between the lower end surface 1c and the tip portion 15a of the contact member 15 can be sufficiently reduced. Therefore, the inclination of the objective lens 2 can be adjusted smoothly and with high accuracy.

FIG. 5 is a side sectional view showing a schematic structure of the optical pickup device according to the second embodiment of the present invention. In FIG. 5, members corresponding to the members described with reference to FIGS. 1 and 2 are designated by the same reference numerals and the description thereof will be omitted.

The lower end surface 21c, which is the contact surface of the objective lens actuator 1 with respect to the optical block 3, is formed as an inclined surface. The lower end surface 21c is the principal point P of the objective lens 2.
Is formed so as to be an inclined surface that contacts a virtual spherical surface having a radius R2.

Further, a low-friction layer 21d is formed by coating Teflon, which is a low-friction substance, on the surface of the lower end surface 21c inside the screw 6, which is the contact area with the optical block 3.

Also in the second embodiment, the inclination of the objective lens 2 is adjusted by the same method as in the first embodiment.

During tilt adjustment, the objective lens actuator 1
The lower end surface 21c of the optical block 3 slides in line contact with the upper end edge of the opening 3b of the optical block 3. Normally, the adjustment angle for tilting the objective lens actuator 1 when adjusting the tilt of the objective lens 2 is about 1 ° at the maximum. Here, the lower end surface 21c
Is an inclined surface that is in contact with an imaginary spherical surface centered on the principal point P, and if the adjustment angle is within 1 °, the displacement between the objective lens 2 and the disc (not shown) will be minute, and It does not affect the performance of the pickup device.

Further, the low friction layer 21d is formed in the contact area of the lower end surface 21c.
Since the frictional force between the lower end surface 21c and the optical block 3 can be reduced during the tilt adjustment, the tilt adjustment of the objective lens 2 can be performed smoothly and highly accurately. Further, even if the low friction layer is formed on the upper edge side of the opening 3b of the optical block 3, the same effect as the formation of the low friction layer 21d on the lower end surface 21c can be obtained. Further, since the lower end surface 21c is formed into an inclined surface, the processing process can be simplified as compared with the case where the lower surface 21c is formed into a spherical surface, so that the processing cost can be suppressed.

[0038]

As described above, according to the present invention,
The objective lens is provided with a concave portion formed at a position facing the objective lens actuator of the optical block, and three or more spherical bodies rotatably fitted in the concave portion, and the lower end portion is brought into contact with the spherical body. Since the sphere is driven by the lower end portion of the objective lens actuator during tilt adjustment, the objective lens actuator can be tilted with a small operating force, so that tilt adjustment can be performed smoothly. And it can be performed with high accuracy.

Further, since the contact surface of the objective lens actuator with respect to the optical block is formed as a conical surface which comes into contact with a virtual spherical surface having a center in the objective lens, the objective lens is prevented from being displaced during tilt adjustment. Since it can be suppressed, the displacement of the light spot irradiated by the objective lens can be suppressed, and it is easier to form the contact surface as an inclined surface as compared with, for example, forming a spherical surface, so that the processing process can be simplified. By forming a low friction layer on at least one of the contact surface or the contact portion of the optical block with respect to the objective lens actuator, contact between the contact surface of the objective lens actuator and the optical block during tilt adjustment can be achieved. Since the frictional force generated between the lens and the lens can be reduced, the tilt of the objective lens can be adjusted smoothly, One can be performed with high accuracy.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a schematic configuration of an optical pickup device that is a first embodiment of the present invention.

FIG. 2 is a perspective view showing an example of a main part in the first embodiment.

FIG. 3 is a perspective view showing another example of the main parts in the first embodiment.

FIG. 4 is a perspective view showing another example of the main part of the first embodiment.

FIG. 5 is a side sectional view showing a schematic configuration of an optical pickup device which is a second embodiment of the present invention.

[Explanation of symbols]

1 ... Objective lens actuator, 1c, 21c ... Lower end surface,
3 ... Optical block, 11, 13 ... Recess, 12 ... Sphere, 14
… Cylindrical body, 15… Abutting member, 15a… Tip, 21d… Low friction layer.

Claims (3)

[Claims] 1. An optical pickup device comprising an objective lens actuator, an optical block for supporting the objective lens actuator, and means for adjusting an inclination of the objective lens actuator with respect to the optical block, comprising: The objective lens is provided with a concave portion formed at a position facing the objective lens actuator, and three or more spheres rotatably fitted in the concave portion, and the lower end portion of the objective lens actuator is brought into contact with the spherical body. An optical pickup device, which is configured to adjust the tilt of an actuator. 2. An objective lens, an objective lens actuator for supporting the objective lens, an optical block for supporting the objective lens actuator, and means for adjusting an inclination of the objective lens actuator with respect to the optical block. In the optical pickup device,
An optical pickup device, wherein a contact surface of the objective lens actuator with respect to the optical block is formed to be an inclined surface in contact with a virtual spherical surface having a center in the objective lens. 3. The optical pickup device according to claim 2, wherein a low-friction layer made of a low-friction material is formed on at least one of the contact surface and the contact portion of the optical block with respect to the objective lens actuator.