JPS63149839A - Objective lens driver - Google Patents

Abstract

PURPOSE:To stably adjust the inclination of an objective lens by providing one supporting point and two adjusting points between a base and an optical block, and varying the height of the base by means of tiny hollow screws for adjusting two points assembled on the optical block in centering the fulcrum. CONSTITUTION:For the purpose of forming an optical spot whose aberration is small on a recording medium, the optical axis of an optical beam radiated by the optical block and the center axis of the objective lens 1 to condense the optical beam are made parallel with each other, and for this purpose, the height of the base 10 is adjusted by moving up or down said hollow screws 14 assembled on the optical block. Thereafter, the base 10 and the optical block is fixed with each other with screws which are approximately coaxial with the center axes of the hollow screws 14, said former screws being penetrating the hollow screws and thereby penetrating a screw hole made through the optical block. At this time of adjusting, since the adjusting points 11a, 11b are approximately coincident with the fixing points 12a, 12b, a moment hardly occurs. In such a way, the adjusting of the inclination of the titled driver is made easy and can be stably achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an objective lens driving device for an apparatus for optically writing or reading information onto or from a disc-shaped recording medium.

2. Description of the Related Art A conventional method for adjusting the inclination of an objective lens in this type of objective lens driving device has a button structure as shown in FIG.

That is, by moving the adjusting insect screw 26 up and down as shown in FIG. After adjusting the inclination of the entire objective lens drive device with respect to the optical block 15 so that the irradiated light beam is approximately flat, the base 10 and the optical block 15 are screwed together as shown in FIG. 3(B). 17
Secure with screws.

Problems to be Solved by the Invention However, in the method for adjusting the inclination of the structure as shown in FIG. 4, the adjustment insect screws are attached at the adjustment points 11a and 11b and the position fixing point 12a of the set screw.

12b is misaligned, as shown in FIG. 3(B), when fixing with the setscrew 17 after determining the inclination with the adjustment insect screw 25, the moment with the adjustment insect screw 25 as a fulcrum is There are problems in that the force M acts, leaving stress and strain on the base 10 of the objective lens driving device, and at the same time, it is difficult to make subtle adjustments to the inclination due to the deformation of the base 1o.

The present invention provides an objective lens driving device that realizes a stable tilt adjustment method in which stress and distortion do not remain when the base is fixed.

Means for Solving the Problems In order to achieve the above object, the present invention provides a hollow insect screw that is attached to an optical block and configured to change the height of the base by moving it up and down, and a central axis of the hollow insect screw. It has an optical block or a threaded part drilled in the base coaxially, and the base and the optical block are screwed and fixed through the hollow part of the hollow insect screw.

According to the above-described structure, the present invention adjusts the inclination by raising and lowering the height of the base with a hollow insect screw, and after adjusting the inclination, fixes the base and the optical block with, for example, a set screw. When fixing, no moment force acts between the hollow screw for tilt adjustment and the set screw for fixing, so no stress or strain is generated on the base, and subtle changes in tilt can be suppressed without deforming the base. .

Example Hereinafter, one embodiment of the present invention will be described based on the drawings.

The first diagram is a plan view of an objective lens driving device according to an embodiment of the present invention, and the direction of the first diagram is a front view of the same.

In FIG. 1, 1 is held in a lens holder 2,
゛ Along with lens holder 2, the first
An objective lens that constitutes the movable part of the optical system forms a light spot on a recording medium on which information can be optically written or read.

Denoted at 5a to 6d are leaf springs, which are provided so that the lens holder 2 can be moved in the focusing direction F by a focusing coil 9. Reference numeral 3 denotes a second movable part connected by leaf springs 5a to 5d, and a tracking coil is attached so that the first movable part and the second movable part 3 can rotate in the tracking direction T about an axis 4. 8a and 8b are arranged in the gap of a magnetic circuit consisting of magnets 6a to 6c and magnetic strings 7a to 7c.

10 is a base, and between the base 1o and the optical block 15 shown in FIG. 2, there is one fulcrum 13 for fixing the base 1o and the optical block 16 and two adjustment points 11a,
Fixed point 12 is approximately the same as b and adjustment points 11a and 11b.
a and 12b are provided, and are arranged so that the fulcrum 13 and the line connecting one adjustment point 11a and the other adjustment point 11b are approximately at right angles.

Next, the structure near the adjustment points 11a and 11b will be described in more detail with reference to FIG.

In FIG. 2, 14 indicates two adjustment points 11a.

11b, and the optical block 1
5, and has a middle threaded part that engages with the first threaded part so as to change the height at the two adjustment points 11a and 11b of the base 1o by rotating and moving it up and down. With a bug screw.

By moving the hollow insect screw 14 up and down, the optical axis of the light beam and the central axis of the objective lens 1 are adjusted to be substantially parallel. Reference numeral 16 denotes a second threaded portion formed in the optical block 15 substantially coaxially with the central axis of the hollow screw 14, and 17 a set screw for screwing and fixing the base 1o and the optical block 16 through the hollow portion of the hollow screw 14. It is.

The operation of the objective lens driving device of this embodiment configured as described above will be described below.

In order to form a light spot with little aberration on the recording medium, it is necessary to make the optical axis of the light beam emitted from the optical block 16 substantially parallel to the central axis of the objective lens that focuses the light beam.

Therefore, as shown in FIG.
As shown in FIG. 0, the hollow part of the hollow part screw 14 is inserted into the threaded part 16 made in the optical block 16 approximately coaxially with the center axis of the hollow part screw 14 for adjustment, and the base 1o and the optical block 15 are fixed with a screw. Fix with screws 17. At this time,
As shown in FIG. 1(c), since the adjustment points 11a, 11b and the fixed points 12a, 12b are approximately the same, no moment force is generated. It can be done stably.

It goes without saying that the adjustment will be made easier if the hollow part of the adjusting hollow screw 14 is made into a regular hexagonal shape so that the inclination can be adjusted using a hexagonal wrench. Also,
At the fulcrum 13, the base 10 may be provided with a spherical convex portion or a concave portion, and the optical block 16 may be provided with a spherical concave portion or convex portion having the same radius of curvature as the convex portion or concave portion of the base 10.

Furthermore, in this embodiment, the second screw portion 1e is the optical block 1.
However, the base 10 may be provided with a second screw portion, and a set screw 1 may be inserted from the optical block 15 side to fix the base 10 and the optical block 15.

Effects of the Invention The present invention provides an objective lens driving device having a mechanism for adjusting the central axis of an objective lens that forms a light spot on a recording medium and the optical axis of a light beam irradiated onto the objective lens to be approximately parallel to each other. Then, set one fulcrum and two adjustment points between the base and the optical pro, and move the two adjustment hollow screws attached to the optical block up and down with the fulcrum as the center. Adjust the tilt of the objective lens by changing the height of the base. After that, by screwing and fixing the base and the optical block through the hollow part of the hollow part screw, using a screw part drilled in the optical block approximately coaxially with the central axis of the hollow part screw,
It is possible to make it difficult to generate a moment force between the adjustment point and the fixed point, and it is possible to realize an objective lens driving device capable of stable tilt adjustment without stress and strain remaining on the base.

[Brief explanation of the drawing]

The first diagram is a plan view of an objective lens driving device according to an embodiment of the present invention, FIG. 1(B) is a front view of the same, and FIG. (B) is a cross-sectional view of the main part showing the main part structure of this embodiment, FIGS. 3(A) and (B) are main part cross-sectional views showing the main part structure of the conventional objective lens driving device, and FIG. 4 is a plan view of a conventional objective lens driving device, and FIG. 4) is a front view of the same. 1... Objective lens, 2... Lens holder, 3... Second movable part, 4... Axis,
5a-6d...Plate spring, 6a-6c...
・Magnet, 7a-7c...Magnetic yaw, 8a, 8
b...Tracking coil, 9...
Focusing coil, 10. River...Base, 11a. 11b...adjustment point, 12a, 12b・middle・
・Fixing point, 13...Fully point, 14...Hollow part screw, 14a...Hollow screw part, 16...
・Optical block, 15a...First screw part, 16
...Second screw part, 17. River... Set screw. Name of agent: Patent attorney Toshio Nakao and one other person lo
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+Koujo Nera f! ;fL-1te 14 volume I; wholesale

Claims (4)

[Claims] (1) A device for optically writing or reading information on a recording medium, which has a central axis of an objective lens for forming a light spot on the recording medium, and a function for shaping and irradiating a light beam. a mechanism for adjusting the inclination of the light beam irradiated from the optical block to the objective lens so as to be substantially parallel to the optical axis, and the optical block and the base are arranged between the optical block and the base. One fixed point and two adjustment points are provided, and the above-mentioned 2.
At each adjustment point, a hollow insect screw is attached to the optical block and can be moved up and down to change the height of the base at each adjustment point; 1. An objective lens driving device comprising a block or a threaded portion drilled in the base, the base and the optical block being fixed by screws through the hollow portion of the hollow insect screw. (2) The objective lens driving device according to claim 1, characterized in that the hollow portion of the hollow insect screw has a regular hexagonal shape. (3) A spherical convex or concave portion is provided on the base at one fulcrum, and a spherical concave or convex portion having the same radius of curvature as the convex or concave portion of the base is provided on the optical block. An objective lens driving device according to claim 1. (4) A patent claim characterized in that the line connecting one fulcrum, one of the two adjustment points, and the line connecting the other adjustment point are approximately at right angles. Range 1
The objective lens drive device described in .