JPH05189773A - Optical pickup device - Google Patents

Abstract

PURPOSE:To provide the optical pickup device which can adjust and position an optical axis with high accuracy and does not move the position of the optical axis even if an objective lens is moved for the purpose of controlling the position of a focus. CONSTITUTION:A contact part of a cell 9 for holding the objective lens 1 with a collar 10 is formed to a projecting spherical surface of a radius r' around the principal point of the objective lens 1 and the contact part of the collar 10 is formed to a recessed spherical shape of a radius r'. The cell 9 and the collar 10 are formed of transparent ABS or polycarbonate, etc. The cell 9 and the collar 10 and further the collar 10 and a bobbin 12 are fixed by a UV curing type a adhesive.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup device used for an information recording / reproducing device such as an optical disk drive device and a magneto-optical disk drive device, and particularly, to easily and highly accurately adjust an optical axis of an objective lens. The present invention relates to an optical pickup device that can be used.

[0002]

2. Description of the Related Art In a recording / reproducing apparatus for recording / reproducing information by forming a light spot on the information recording medium, in order to accurately record / reproduce information, the direction of the optical axis of the objective lens is accurately set. It is necessary to match the direction of the normal of the recording surface of.

FIG. 3 is a sectional view showing an example of the configuration of a conventional optical pickup device.

The optical pickup device comprises an objective lens 1, a bobbin 2 that holds the objective lens 1, an actuator base 3 that serves as a fixed base for the bobbin 2, and an optical block 4 that emits a laser beam L to the objective lens 1. Has been done.

A plate-shaped bobbin 2 for holding the objective lens 1 is provided with a hole 2a penetrating in the thickness direction, and a focusing coil 5 is arranged on a side surface of the bobbin 2 in a magnetic gap (not shown). It is installed as described above. A sliding shaft 6 is planted on the surface of the actuator base 3 facing the bobbin 2. The sliding shaft 6 has a hole 2a in the bobbin 2.
The bobbin 2 is movably held in the optical axis direction of the objective lens 1 by sliding the inner surface of the hole 2a on the sliding shaft 6. Also, actuator base 3
The contact portion with respect to the optical block 4 is formed on a convex spherical surface having a radius r with the principal point o of the objective lens 1 as the center when the objective lens 1 is at a predetermined position. The actuator base 3 has a contact portion slid on the optical block 4 so that the direction of the optical axis of the objective lens 1 coincides with the direction of the normal line of the recording layer 7a of the information recording medium 7 when the device is assembled. Then, the optical axis of the objective lens 1 is tilted and adjusted, and then the actuator base 3 and the optical block 4 are fixed by an appropriate method such as fastening with screws.

A laser beam L emitted from a light source (not shown) of the optical block 4 enters a deflecting mirror 8 via an intermediate optical component, is reflected, and enters an objective lens 1. The laser beam L incident on the objective lens 1 is applied with an electric current to the focusing coil 5 to move the bobbin 2 so that the position of the focal point is controlled and a light spot is formed on the recording layer 7a of the information recording medium 7. To form.

[0007]

When the above optical pickup device is assembled, the direction of the optical axis of the objective lens 1 is changed to
The spherical contact portion of the actuator base 3 is adjusted by sliding the optical block 4 so as to match the normal direction of the recording layer 7a of the information recording medium 7. As shown in FIG. Is mounted on the bobbin 2 in an inclined manner, in order to match the optical axis direction with the normal direction, the actuator base 4 is adjusted so that the center line of the sliding shaft 6 is tilted with respect to the normal direction. There is a need to.

In FIG. 4, the length of the sliding shaft 6 is extended in order to make it easier to understand the influence of the inclination of the sliding shaft 6.

Objective lens 1 shown by solid lines
When the slide shaft 6 is moved from the position of to the position shown by the chain line, the optical axis moves from a to a ′ because the sliding shaft 6 is inclined. Generally, the diameter of the light spot is about 1 μm, and the size of the information track corresponds to the diameter of the light spot. Therefore, even a slight deviation of the optical axis is an obstacle to recording and reproduction.

After adjusting the optical axis, the actuator base 3
If the force is fixed by applying a force from the outside with a screw or the like, the position of the actuator base 3 is displaced at the time of fixing, which causes a problem that the optical axis of the objective lens 1 cannot be positioned with high accuracy.

In order to solve the above problems, an object of the present invention is to adjust the optical axis with high accuracy and position it, and to control the position of the focus point, the position of the optical axis does not move even if the objective lens is moved. It is to provide a pickup device.

[0012]

In order to achieve the above object, the present invention provides an objective lens for focusing a light beam on an information recording medium, a cell holding the objective lens, and a color holding the cell. In an optical pickup device provided with a bobbin that holds this color and is movable in the normal direction of the recording surface of the information recording medium, the contact portion of the cell with respect to the color is centered on the principal point of the objective lens. It is characterized in that it is formed in a convex spherical surface, and the direction of the optical axis of the objective lens can be adjusted by sliding the contact portion of the cell to the collar.

Further, the contact portion of the color with the cell is formed in a concave spherical surface centering on the principal point of the objective lens.

Further, the cell and the collar are made of a transparent material, and the cell and the collar, and the collar and the bobbin are fixed by a photo-curing adhesive.

[0015]

According to the above means, the contact portion of the cell with respect to the collar is formed as a convex spherical surface, so that the optical axis of the objective lens can be adjusted by sliding the cell on the collar. Therefore, it is not necessary to tilt the bobbin that holds the collar, and the position of the optical axis does not shift even if the objective lens is moved to control the focus.

Further, since the contact portion of the collar with respect to the cell is formed in the concave spherical surface, the cell smoothly slides on the collar.

Further, since the cell and the collar are made of a transparent material, and the cell and the collar, and the collar and the bobbin are fixed by the photo-curing adhesive, no force is applied from the outside at the time of fixing.

[0018]

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

FIG. 1 is a cross-sectional view showing the structure of an embodiment of the present invention. Members corresponding to the members described with reference to FIG. 3 in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

The objective lens 1 is held in the cell 9,
The cell 9 is held by the collar 10 and the collar 10 is held by the bobbin 12. The sliding shaft 16 is directly implanted in the optical block 4, and is fixed so that the direction of the center line thereof coincides with the normal direction of the recording layer 7a.

The cell 9 is provided with a through hole 9a, and the peripheral portion of the objective lens 1 is pressed against the inner surface of the through hole 9a.
The objective lens 1 is fixed. The contact portion of the cell 9 with the collar 10 forms a convex spherical surface having a radius r'with the principal point of the objective lens 1 as the center. The contact portion of the collar 10 with the cell 9 forms a concave spherical surface having a radius r'with the principal point of the objective lens 1 as the center. Cell 9 and color 10 are made of transparent acrylonitrile-butadiene-
It is made of styrene copolymer resin (ABS), polycarbonate, etc., and each contact portion is processed smoothly.

Since the contact portion between the cell 9 and the collar 10 is formed into a convex and concave spherical surfaces having the same radius, it is possible to adjust the direction of the optical axis of the objective lens 1 when the apparatus is assembled. , By sliding the cell 9, the objective lens 1
The optical axis can be smoothly tilted about the principal point of, and the direction of the optical axis can be adjusted with high accuracy.

Further, the direction of the optical axis can be adjusted only by sliding the cell 9, and the sliding shaft 16 which holds the bobbin 12 slidably does not have to be tilted, so that the focus is controlled. Therefore, even if the objective lens 1 moves, the position of the optical axis does not shift, and the light spot is condensed at a predetermined position. The position of the optical axis can be adjusted by moving the collar 10 on the bobbin 12.

An example of a method of adjusting the direction of the optical axis of the objective lens 1 and a method of fixing the cell 9 and the bobbin 10 will be described with reference to FIG.

The cell 9 is fixed to the grip portion 21 of the optical axis adjusting device whose body is not shown. An ultraviolet curable adhesive is applied to the contact portion of the color 10 with the cell 9 to form an adhesive layer 10a, and an adhesive layer 10b is similarly formed on the contact surface with the bobbin 12, and the color 10 is placed on the bobbin 12. .. Next, from the position of the bobbin 12 shown in the figure, an electric current is applied to the focusing coil 5 to move the bobbin 12 upward to move the collar 10 to the cell 9
Press against.

The grip portion 21 of the optical axis adjusting device has the cell 9 in a surface direction (direction of arrow A) having the optical axis as a normal line and a rotation direction (direction of arrow B) about the principal point o of the objective lens 1. ) And can be moved to.

The laser beam L is emitted from the optical block 4 to the objective lens 1 and focused on the objective lens 1, and the position and the direction of the optical axis of the formed light spot are detected by the spot monitor 31.

On the basis of the detection signal from the spot monitor 31, the optical axis adjusting device determines the direction of the optical axis and sets the cell 9 to the color 10
The position of the light spot is adjusted by sliding the collar 10 on the bobbin 12.

Then, by irradiating the cell 9 made of a transparent material and the color 10 with ultraviolet rays from the ultraviolet lamp 32, the adhesive layers 10a, 10b made of an ultraviolet curable adhesive are cured, and the cell 9 and the color 10 are cured. And again, color 10 and bobbin
Fix 12 and.

After adjusting the optical axis, by fixing the cell 9 and the collar 10 and the collar 10 and the bobbin 12 with an ultraviolet curing adhesive, a force is not applied from the outside at the time of fixing, so that the positioning is performed with high accuracy. It becomes possible to fix it.

Further, in the above optical pickup device, the direction of the optical axis and the position of the light spot can be adjusted at the time of assembling, and the adjustment does not have an adverse effect on recording and reproduction, so the device is constructed. It is possible to reduce the dimensional tolerance of the parts to be assembled and the assembly accuracy of the parts, and it is possible to reduce the cost of the device and the number of steps.

[0032]

As described above, according to the present invention,
By forming the contact part for the color of the cell on the convex spherical surface and sliding the cell with respect to the color and adjusting the optical axis, the optical axis does not move due to the movement of the objective lens in the optical axis direction. It is possible to provide an optical pickup device capable of allowing a recording / reproducing device to normally perform recording / reproducing, and by forming a contact surface for a color cell on a concave spherical surface, a sliding for adjusting an optical axis is provided. The operation can be performed smoothly, the direction of the optical axis can be adjusted with high accuracy, and the cell and the color are made of a transparent material, and the cell and the color, and the color and the bobbin are light-curing type adhesive. By fixing with an agent, no external force is applied when fixing,
An optical pickup device that can perform positioning with high accuracy can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an example of an apparatus used in this embodiment and during assembly and adjustment.

FIG. 3 is a cross-sectional view showing an example of the configuration of a conventional optical pickup device.

FIG. 4 is a cross-sectional view showing the operation of the bobbin in this example.

[Explanation of symbols]

1 ... Objective lens, 2, 12 ... Bobbin, 3 ... Actuator base, 4 ... Optical block, 5 ... Focusing coil, 6, 16 ... Sliding axis, 7 ... Information recording medium,
7a ... recording layer, 9 ... cell, 10 ... color, 10a, 10b
… Adhesive layer.

Claims (3)

[Claims] 1. An objective lens for focusing a light beam on an information recording medium, a cell holding the objective lens, a color holding the cell, and a normal line of a recording surface of the information recording medium holding the color. In an optical pickup device provided with a bobbin movable in a direction, a contact portion of the cell with respect to the collar is formed into a convex spherical surface centering on a principal point of the objective lens, and the contact portion of the cell is slid onto the collar. An optical pickup device characterized in that the direction of the optical axis of the objective lens can be adjusted by moving the objective lens. 2. The optical pickup device according to claim 1, wherein a contact portion of the color with respect to the cell is formed in a concave spherical surface centering on a principal point of the objective lens. 3. The cell and the collar are made of a transparent material, and the cell and the collar, and the collar and the bobbin are fixed by a photo-curing adhesive. Item 2. The optical pickup device of item 2.