JPS62267927A - Optical pickup - Google Patents

Abstract

PURPOSE:To hold the inclination of the optical axis of an adjusted objective even when an external force is applied by fixing an objective lens driving device and an optical system main body rigidly. CONSTITUTION:Bolts 5c and 5d are pressed down by a floating coupling part consisting of coil springs 4c and 4d and the bolts 5c and 5d to energize the objective driving device 2 and optical system main body 3 in approaching directions and also allow the both to be displaced in both leaving and approaching directions. A bolt 5e which constitutes a fixed part is fixed opposite a semifixed coupling part across the slide contact part between a projection part 6 and a recessed part 7 so that the objective driving device 2 and optical system main body 3 are not displaced in the leaving directions. Then, the objective driving device 2 and optical system main body 3 are fixed rigidly by the bolts 5a and 5b, and 5e across the projection part 6 and recessed part 7 as fulcra. When the inclination is adjusted, the bolts 5a, 5b, and 5e are turned.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an improvement in an optical pickup having a mechanism for adjusting the inclination of an objective lens with respect to an optical disk.

Conventionally, there is an optical pickup having an objective lens tilt adjustment mechanism as shown in FIGS. 3 and 4 (see Japanese Patent Laid-Open No. 59-223953).

The optical pickup A is composed of an objective lens drive bag @2 that holds an objective lens 1, and an optical system body 3 that emits a beam that is incident on the objective lens 2, and both are provided in the objective lens drive device 2. A spherical surface 2a bulging toward the optical system main body 3 side and a concave spherical surface 3 formed on the optical system main body 3
coil springs 4a, 4b,
4c, 4d, and bolts 5a, 5b, 5c, and 5d to allow relative displacement.

In the conventional optical pickup A having such a configuration,
By adjusting the bolts 5a and 5b, the optical axis of the objective lens 1 can be tilted relative to the optical system main body 3 and an optical disk (not shown).

However, in the conventional optical pickup A described above, the objective lens driving device 2 and the optical system main body 3 are connected to the biasing forces of the coil springs 4a, 4b, 4c, and 4d.
Since the position is determined only by the frictional force between the spherical surface 2a and the spherical surface 3a, when an external force such as vibration is applied,
There is a problem in that the objective lens driving device 2 sometimes oscillates or does not return to the set position after being deviated, and the inclination of the optical axis of the objective lens 1 is not stable.

This invention was made in view of the above problems.
It is an object of the present invention to provide an optical pickup that can maintain the adjusted inclination of the optical axis of an objective lens even when an external force such as vibration is applied.

In order to achieve the above-mentioned objects, the present invention aims to solve the above problems by connecting the objective lens driving device and the optical system main body so that the convex portion and the concave portion are in sliding contact and can be relatively displaced by four connecting portions. In the optical pickup, a pair of adjacent connecting portions among the four connecting portions are semi-fixed connecting portions that bias the objective lens drive device and the optical system body in the direction of separation and limit displacement in the direction of separation. , the connecting portion other than the semi-fixed connecting portion is a floating connecting portion that biases the objective lens driving device and the optical system body in the approaching direction and allows displacement of both in both directions of separation and approach, and a convex portion and a concave portion are formed. A fixing part is provided at the part facing the semi-fixed connecting part across the sliding contact part to prevent separation of the objective lens drive device and the optical system main body, so that the objective lens drive device and the optical system main body can be rigidly fixed. It is characterized by the following.

Since this invention has the above-described configuration, the objective lens driving device and the optical system main body can be rigidly fixed, and the adjusted tilt of the objective lens can be adjusted even when an external force such as vibration is applied. It can also be held.

The present invention will be explained below based on the drawings. FIGS. 1 and 2 show an embodiment of the present invention. In the figure,
The same reference numerals are given to parts or members that are the same or equivalent to the conventional ones.

The optical pickup B includes a substantially rectangular parallelepiped objective lens driving device 2 that holds the objective lens 1 and moves the objective lens 1 in the focusing direction and the tracking direction of an optical disk (not shown).

Optical system main body 3 that emits a beam emitted from the objective lens 1 and records a signal on an optical disk, or detects a return beam reflected by the optical disk and reads the signal.
It consists of

A convex portion 6 is formed on the objective lens driving device 2, and
Five screw holes 8a, 8b, 8c, 8d surround the convex portion 6,
8e, and a through hole 6a penetrating through the center of the convex portion 6 to the objective lens 1 side.

A recess 7 is formed in the optical system main body 3, and a screw hole 8a is formed in the optical system main body 3.
, 8b, 8c, 8d, and 8s are provided with through holes 9a, 9b, 9c, 9d, and 9e into which bolts 5a, 5b, 5c, 5d, and 5e are loosely inserted.

These through holes 9a, 9b, 9c, 9d, and 9e include
The heads of the bolts 5a, 5b, 5c, 5d, and 5e or the flanges to which the coil springs 4a, 4b, and 4c and 4d come into contact are respectively formed, and among them, the through holes 9
The flanges 10b and 10e formed in the first through hole 9d are spaced apart from the opening on the objective lens driving device 2 side, as shown in FIG.
is provided at the opening on the objective lens driving device z side.

Note that although not shown in the drawings, a flange 10 is provided in the through hole 9a.
A flange is formed at the same position as in b.

A flange is formed in the through hole 9c at the same position as the flange 10d.

In this example, the convex part 6 and the concave part 7 are both constituted by spherical surfaces that share the center O with the objective lens 1, as shown in FIG. Even when the objective lens driving device 2 and the optical system main body 3 are displaced in any direction, the center ○ of the objective lens 1 and the optical system main body 3
The central axis Q of the beam emitted from the center will not deviate from the center axis Q of the beam.

The objective lens driving device 2 and the optical system main body 3 are connected movably through four connecting portions, of which two adjacent
The two connecting parts are coil springs 4a, 4b and bolts 5.
It is a semi-fixed connection part consisting of a and 5b.

The other two connections are floating connections consisting of coil springs 4c, 4d and bolts 5c, 5d.

In the semi-fixed connection part, coil springs 4a and 4b are arranged closer to the objective lens drive device 2 than the flanges of the through holes 9a and 9b, and bias the objective lens drive device 2 and the optical system main body 3 in the direction of separation. The bolts 5a and 5b are screwed to the optical system main body 3 and abut the flanges of the through holes 9a and 9b from the side opposite to the coil springs 4a and 4b to prevent displacement only in the direction of separation.

Moreover, in the floating connection part, a coil spring 4c.

4d is disposed closer to the optical system main body 3 than the flanges of the through holes 9c and 9d, and by pushing down the bolts 5c and 5d, the objective lens driving device 2 and the optical system main body 3 are urged in the approaching direction, and It is possible for both to move toward and away from each other.

The bolts 5e constituting the fixing part are arranged so that the objective lens driving device 2 and the optical system main body 3 are not displaced in the direction of separation at the part facing the semi-fixed coupling part by sandwiching the sliding contact part between the convex part 6 and the concave part 7. The objective lens device 2 and the optical system main body 3, which have been positioned, are rigidly fixed by bolts 5a and 5b and a bolt 5e, which sandwich the convex portion 6 and the concave portion 7 as fulcrums. .

The tilt adjustment is performed by turning the bolts 5a, 5b, and 5e. In FIG. 2, when tilting the objective lens drive device 2 to the right, loosen the bolt 5e, then loosen the bolt 5a.
When tightening bolt 5b and tilting it to the left, tighten bolt 5.
Loosen bolts a and 5b, then tighten bolt 5e.

After adjusting the inclination in this way, if the objective lens drive device 2 and the optical system main body 3 are rigidly fixed with the bolts 5e, the relative positional relationship between the two can be maintained even when external forces such as vibrations are applied during use. can be kept as it was when set.

As explained above, in the optical pickup according to the present invention, the objective lens driving device and the optical system main body are connected to each other so that the convex portion and the concave portion are in sliding contact and are movable relative to each other by four connecting portions. In the optical pickup, a pair of adjacent connecting parts among the four connecting parts are semi-fixed connecting parts that bias the objective lens drive device and the optical system body in the direction of separation and limit displacement in the direction of separation. The connecting portion other than the fixed connecting portion is a floating connecting portion that biases the objective lens drive device and the optical system body in the approaching direction and allows them to be displaced in both directions toward and away from each other. A fixing part that prevents the objective lens drive device from separating from the optical system main body is provided at a part that faces the semi-fixed connection part by sandwiching the contact part, so that the objective lens drive device and the optical system main body can be rigidly fixed. This structure not only makes it easy to adjust the tilt of the objective lens, but also prevents relative shake or misalignment between the objective lens drive device and the optical system body even when external forces such as vibrations are applied. It is possible to provide an optical pickup in which the optical axis of the lens is highly stable.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view of an optical pickup showing an embodiment of the present invention, Fig. 2 is an explanatory view showing a cross section of the optical pickup shown in Fig. 1, and Fig. 3 is an exploded perspective view showing a conventional optical pickup. 4 are explanatory diagrams showing a cross section of the optical pickup shown in FIG. 3. B... Optical pickup... Objective lens 2... Objective lens drive device 3... Optical system body 5e... Bolt (fixing part) 6... Convex portion 7... Concave portion Fig. 3

Claims (1)

[Claims] At least one of the convex portion formed in the objective lens drive device and the concave portion formed in the optical system main body has a spherical surface having a center within the objective lens, and the convex portion and the concave portion slide on the spherical surface. In an optical pickup in which the objective lens driving device and the optical system main body are coupled so as to be relatively displaceable by four coupling parts surrounding the convex part and the concave part, two of the four coupling parts are adjacent to each other. The two connecting portions are semi-fixed connecting portions that urge the objective lens driving device and the optical system body in the direction of separation and only prevent displacement in the direction of separation, and the two connecting portions other than the semi-fixed connecting portion The portion is a floating connecting portion that urges the objective lens drive device and the optical system body in the approaching direction and allows displacement in both directions of separation and approach, and a sliding contact portion between the convex portion and the concave portion. A fixing portion that prevents displacement of the objective lens driving device and the optical system main body in a direction in which the objective lens driving device and the optical system main body are separated is provided at a portion that sandwiches and faces the semi-fixed connecting portion, and the objective lens driving device and the optical system main body are connected to each other. An optical pickup characterized by being rigidly fixable.