JPS6252725A - Tilt adjusting device for optical pickup - Google Patents

Abstract

PURPOSE:To simplify the adjustment by forming incorporatedly a carriage and a pickup main body via a support supported freely tiltedly in the tangential direction of a track of the optical axis of an optical system lens and in a direction crossing with the track. CONSTITUTION:The carriage 15, the pickup main body 18 and the support 21 are formed incorporatedly by using a resin as a raw material and the pickup main body 18 is titled freely to a prescribed angle in the direction of the arrow A by the torsion of the support 21. Further, a screw hole 15c is screwed at one side in the radial direction (x) of the carriage 15, the tip 22a of the screw 22 screwed into the screw hole 15c is in press contact onto the side face of the pickup main body 18 and the pickup main body 18 is fixed to the carriage 15 by the pressing force of the screw 22.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical pickup that reads information recorded on the recording surface of a recording medium such as a compact disc, or writes information on this recording surface. In particular, the present invention relates to an optical pickup tilt adjustment device that can align the optical axis of an optical system lens built into a pickup body so as to be orthogonal to the recording surface of a recording medium.

[Prior Art and Problems to be Solved by the Invention] Conventionally, information recorded on a recording medium such as a compact disc, a video disc, or an optical disc such as a data disc is read or information is written to this recording medium. Various writing optical pickups have been proposed.

FIG. 8 is a principle diagram showing the operation of an optical pick-up of the type that detects a focus error signal by the critical angle method, and is equivalent to that disclosed in, for example, Japanese Patent Laid-Open No. 59-201240. be.

The light beam emitted from the light mi of a semiconductor laser or the like is made into a parallel light beam by the collimator lens 2, and then enters the polarizing prism 3, transmits the polarized light 113a, and reaches the reflecting prism 4. The parallel light beam totally reflected in the right angle direction by the reflecting surface of the reflecting prism 4 passes through the 174-wave plate 5 and is condensed by the objective lens 6, onto the recording surface 10a of the recording medium 10 such as a compact disk with a diameter of approximately image a light spot.

The objective lens 6 is supported within an actuator 11 including a magnet, a yoke, a coil, etc. so as to be movable two-dimensionally in the optical axis and the radial direction of the recording medium 10 perpendicular to the optical axis. This actuator 11 performs focus servo and tracking servo so that the light spot follows the center of the track of the recording medium 10 in a focused state.

The reflected light of the light spot irradiated onto the recording medium 10 follows the same optical path as the outgoing path until it reaches the polarizing film 3a, but on the returning path, its polarization direction is perpendicular to the polarizing direction of the outgoing path due to the action of the 174 wavelength plate 5. Polarized light! It is reflected in the 90° direction at ll3a, passes through the critical angle prism 7, and enters the photodetector 8.

This critical angle prism 7 has an optical surface such that the angle of incidence of the return light from the recording medium 10 with respect to the optical axis is approximately a critical angle, and by reflecting the return light on this optical surface, a photodetector 8 is detected. It is input to. The photodetector 8 also detects a light-receiving surface divided into four parts in the radial direction and tangential direction of the recording medium 10, and obtains a data signal, a focus error signal, and a tracking error signal from the output of this light-receiving surface. It looks like this.

Note that light sources such as the semiconductor laser 1. Photodetector8. Optical system lenses 2 to 7 a3 and actuator 11 are housed in the pickup body, and this pickup body
This carriage is supported by a guide shaft and runs along the recording surface 10a of the recording medium 10,
Moreover, it is designed to reciprocate in a direction across the tracks on this recording surface 10a.

By the way, if the light beam emitted from the objective lens 6 is not irradiated perpendicularly to the recording surface 10a of the recording medium 10, the light spot will not form a perfect circle on the recording surface 10a, and the reflection from the recording surface 10a will occur. The light is no longer incident on the objective lens 6, and as a result, it is difficult to read or write accurate information.

In order to deal with this, for example, in JP-A-58-109835, JP-A-58-109836, JP-A-122241M, or JP-A-59-223952, a WA1 member is interposed between the pickup body and the carriage, and this adjustment member is By tilting the pickup body, the optical axis of the objective lens 6 built into the pickup body is
An adjusting means for orthogonal to the recording surface 10a of the recording medium 10 is disclosed.

However, the tilt adjustment devices disclosed in the above publications are
A separate member is interposed between the carriage and the pickup body, which increases the number of valve parts, complicates manufacturing and assembly, and increases product cost.

In addition, since there are many parts, the entire device becomes larger, and it is necessary to respond to the recent trend toward miniaturization and weight reduction.

[Objective of the Invention] The present invention has been made in view of the above circumstances, and has a simple structure, which facilitates manufacturing and assembly, and which can reduce the cost of the product, as well as reduce the size and weight of the product. The purpose of the present invention is to provide a tilt adjustment device for an optical pickup that can be used.

[Means for solving the problem] In the tilt adjustment device according to the present invention, a pickup body is supported by a carriage that reciprocates along a guide shaft, and the pickup body directs a light beam from a light source onto the recording surface of a recording medium. In an optical pickup that has a built-in optical system lens that irradiates and guides the reflected light from the recording surface to a photodetector, the carriage and the pickup main body are arranged so that the optical axis of the optical system lens tracks with the recording surface. The pickup body is integrally molded via a support part that supports the pickup body so as to be tiltable in at least one direction of the tangential direction of the track and the direction intersecting the track, and by tilting the pickup body around the support part, the recording medium can be The perpendicularity of the optical axis of the optical system lens with respect to the recording surface of the optical system can be adjusted.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

1 to 4 relate to the first embodiment of the present invention, in which FIG. 1 is a plan view of the optical pickup, FIG. 2 is a side view of the same, and FIG.
The figure is a sectional view taken along line mm in FIG. 1, and FIG. 4 is a perspective view of the optical pickup.

In these figures, reference numeral 15 denotes a carriage, and guide holders 15a are integrally formed on both sides of the carriage 15. A pair of mutually parallel guide shafts 15a and 16b are connected to the guide holders 15a via bearings 17. It is slidably inserted. This guide shaft 1
5a and 16b extend along the recording surface 10a of the recording medium 10 and in a direction intersecting the tracks of the recording surface 10a, and both ends thereof are fixed to an equipment frame (not shown). .

Further, a rectangular hole 15b is provided in the center of the carriage 15.
A pickup main body 18 is inserted into the hole 15b. Further, a side surface of the pickup main body 18 in the tangential direction Y and a symmetrical position with respect to the optical axis of the objective lens 6 and a side surface of the hole 15b of the carriage 15 opposite to this position are connected to each other via the support portion 21. are connected. This carriage 15, pickup body 1
8 and the support part 21 are integrally molded products made of resin, and the pickup main body 18 is twisted by the support part 21.
It can be tilted at a predetermined angle in the six directions of arrows in FIG.

Further, a screw hole 15c is screwed on one side of the carriage 15 in the radial direction, and the tip 22a of the screw 22 screwed into the screw hole 15c is connected to the pickup main body 1.
The pickup main body 18 is fixed to the carriage 15 by the pressing force of the screw 22 .

The pickup main body 18 includes a light source 1 similar to that shown in FIG. 8, components 2 to 7 constituting an optical system lens, and a light detector 11:8.

Further, the objective lens 6 is held in a lens frame 20, and this lens frame 2
0 is applied to the actuator 11 in a two-dimensional direction (radial direction
The actuator 11 is supported so as to be movable in the focusing direction F), and the actuator 11 is housed in a cylindrical body 19 that projects from one side of the upper surface of the pickup main body 18 .

Next, the operation of the embodiment with the above configuration will be explained.

First, a light source 1 and an objective lens 6 are placed inside the pickup body 18.
, each member constituting the optical system such as the photodetector 8, and the actuator 11 (see FIG. 8) for correcting the objective lens 6 in two-dimensional directions (radial direction x and focusing direction F) are assembled in a predetermined manner. After the attachment, the guide shafts 16a and 16b are inserted through the guide holders 15a provided on both sides of the main 11-ridge 15 through the bearings 17, and the objective lens 6 assembled to the pickup body 18 is attached to the recording medium 10. It is made to face the recording surface 10a.

When the light beam emitted from the objective lens 6 is somewhat inclined in the tangential direction Y with respect to the recording surface 10a, the pickup main body 18 is
Rotate by a predetermined angle in the six directions of arrows around . Then, the pickup main body 18 rotates about the support part 21 as a fulcrum,
The angle of inclination of the light beam emitted from the objective lens 6 with respect to the recording surface 10a is corrected.

Note that since the rotation angle at this time is minute, the support portion 21
The torsion of the support part 21 is within the allowable elastic limit, so that the support part 21 will not be damaged or its strength will be reduced during adjustment.

Then, the light beam emitted from the objective lens 6 is transmitted to the recording surface 10a1 of the recording medium 10. : When the pickup body 18 is oriented at right angles, tighten the screw 22 screwed into the screw hole 15C of the carriage 15, press its tip 22a against the side of the pickup body 18, and attach the pickup body 18 to the carriage 15. Fix it.

5 to 7 show a second embodiment of the present invention, in which FIG. 5 is a plan view of the optical pickup, FIG. 6 is a sectional view taken along line Vl-Vl in FIG. The figure is a side view of FIG. 5.

The support part 21 in this embodiment is the pickup main body 1
8 in the tangential direction Y and is symmetrical about the optical axis of the objective lens 6, and the side surface of the hole 15b of the carriage 15 facing this position is connected.

The carriage 15, the pickup body 18, and the support part 21 are integrally molded from resin, and the pickup body 18 is tiltable at a predetermined angle in the direction of arrow B in FIG. 7 about the support part 21. .

That is, when the light beam emitted from the objective lens 6 is somewhat inclined in the radial direction the objective lens 6.
The light flux emitted from the main ridge 15 is made perpendicular to the recording surface 10a, and then a screw hole 15 screwed into one side of the main ridge 15 is inserted.
Tighten the screw 22 screwed into C, and tighten the tip 22a.
is pressed against the side surface of the pickup body 18, and the pickup body 18 is set on the carriage 15.

In the illustrated embodiment, the pickup body 18 is fixed to the Gitlidge 15 with screws 22, but the carriage 15, the pickup body 18, and the support part 21 are integrally molded, for example, from thermoplastic resin, and the inclination angle is adjusted. During this process, the support part 21 is heated, and during that time, the pickup body 1
8 to correct the inclination angle of the light beam emitted from the objective lens 6, and after setting, the support part 21 is cooled and hardened, so that the pickup body 18 can be fixed to the carriage 15 without using the screw 22. can be fixed to.

[Effects of the Invention] As explained above, according to the present invention, a pickup body is supported by a carriage that reciprocates along a guide shaft, and a light beam from a light source is irradiated onto the recording surface of a recording medium on this pickup body. In addition, in an optical system lens that guides reflected light from the recording surface to a photodetector, the carriage and the pickup main body are arranged so that the optical axis of the optical system lens is tangential to the track and tangential to the recording surface. Since the pickup body is integrally molded via a support part that supports the pickup body so as to be tiltable in at least one direction intersecting the track, the pickup body can be rotated by a predetermined angle around the support part, and the The inclination angle of the light beam can be corrected, making gJ adjustment work easier.

In addition, the support part, which is the optical axis adjustment mechanism, is integrally molded with the pickup body and carriage, which not only reduces the number of parts and simplifies the structure, but also facilitates manufacturing and assembly. becomes easier.

As a result, the cost of the product can be lowered, and the entire device is smaller? ! ■ It is possible to realize

[Brief explanation of drawings]

1 to 4 relate to the first embodiment of the present invention, in which FIG. 1 is a plan view of the optical pickup, FIG. 2 is a side view of the same, and FIG.
The figure is a sectional view taken along the line ■-■ of FIG. 1, FIG. 4 is a perspective view of the optical pickup, FIGS. 5 to 7 relate to the second embodiment of the present invention, and FIG. 5 is a plan view of the optical pickup. 6 is a sectional view taken along the line VI-VI in FIG. 5, FIG. 7 is a side view of FIG. 5, and FIG. 8 is a principle diagram showing the operation of the optical pickup. DESCRIPTION OF SYMBOLS 1... Light source, 2-7... Optical system lens, 8... Photodetector, 10... Recording medium, 10a... Recording surface, 1
5... Carriage, 16a, 16b... Guide shaft, 18... Pickup body, 21... Support part, Y... Track direction, X... Direction intersecting the track. Figure 1 Figure 3 @ Figure 4

Claims (1)

[Claims] The pickup body is supported by a carriage that reciprocates along a guide shaft, and the pickup body is equipped with an optical system that irradiates the recording surface of the recording medium with a light beam from a light source and guides the reflected light from the recording surface to a photodetector. In an optical pickup having a built-in lens, the carriage and the pickup main body are supported so that the optical axis of the optical system lens can be tilted with respect to the recording surface in at least one of a tangential direction to a track and a direction intersecting the track. A tilt adjustment device for an optical pickup, characterized in that the device is integrally molded with a support portion interposed therebetween.