JPS6240642A - Optical pickup - Google Patents

Abstract

PURPOSE:To improve optical characteristics with light weight and high strength of forming a pickup main body containing an optical system and an actuator with plastic and forming integrally a reinforcement member having many open holes in the main body. CONSTITUTION:The optical pickup is constituted to contain the optical system or the like in the pickup main body 21. The pickup main body 21 is made of a material such as plastic and formed as a rectangle box whose upper side is opened. Further, the pickup main body 21 is formed integrally by giving a reinforcement member 22 made of metallic net in its side wall. Moreover, a cover 30 is given to the upper opening of the pickup main body 21 and a long hole 30a through which an objective lens 28 is exposed the cover is pierced. Through the constitution of main body above, the optical characteristic is improved with light weight and high strength.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Field of Industrial Application The present invention relates to an optical pickup used for recording and reproducing signals on an optical disc.

[Prior art and problems to be solved by the invention] Conventionally, audio discs, video discs, data discs,
Various pickups have been proposed for recording and reproducing signals on optical discs such as discs.

For example, there is one shown in FIG. This optical pickup is designed to detect a focus error signal from within the critical point.

A light beam emitted from a light source 1 is collimated by a collimator lens 2, then enters a polarizing prism 3, passes through the polarizing film 4, and then hits a reflective surface 5 of a reflective prism. The parallel light beam totally reflected in the right angle direction by the reflecting surface 5 passes through the 174-wavelength plate 6, is converged by the objective lens 7, and is imaged on the optical disk 8 as a light spot with a diameter of about 1. The objective lens 7 is supported within an objective lens actuator 9 including a magneto, a yoke, a coil, etc., so as to be movable in two axes: the optical axis and the radial direction of the optical disk 8 perpendicular to the optical axis.
The focusing servo J3 and the tracking servo are performed so that the light spot follows the center of the track of the optical disk 8 in a focused state by being driven in the directions of the two axes mentioned above. The reflected light from the optical disk 8 of the optical spot follows the same optical path as the outward path until it reaches the polarizing film 4, but on the return path it follows the same optical path as the outward path.
Due to the action of the 74-wavelength plate 6, the direction of polarization is perpendicular to the direction of polarization on the outgoing path, so the light is reflected off the polarizing film 4. This polarized light P
The return light from the optical disk 8 reflected by the IA 4 is incident on the photodetector 11 via the critical angle prism 10. The critical angle prism 10 has an optical surface such that the incident angle of the returned light from the optical disk 8 with respect to the optical axis is approximately a critical angle, and by reflecting the returned light on this optical surface, it is reflected to the photodetector 11. It is incident. Further, the photodetector 11 has four light-receiving areas divided into two in the radial direction and the tangential direction of the optical ice f 8, and these light-receiving areas f
A data signal, a focus error signal, and a dragging error signal are obtained from the output of f[.

The optical system including the light source 1, collimator lens 2, polarizing prism 3, reflection prism 5, objective lens 7, critical angle prism 10, photodetector 11, etc., and the objective lens actuator 9, etc. having the +if structure are formed in a box shape. It is stored inside the pickup body. Then, the feed guide bearing, rack, etc. are attached to this pickup body, and the feed drive 5
) J is set to take place.

Incidentally, for example, Japanese Patent Application Laid-Open No. 57-173656 or Japanese Patent Application Laid-Open No. 59-201240 discloses a conventional technique for optical pickup with the above structure.

However, with such conventional technology, if the pickup body is molded with plastic deck to make it smaller and lighter, it may suffer mechanical deformation when dropped, or thermal deformation at high temperatures when placed in a car. This sometimes caused the viscosity of the optical system to go out of order, making accurate reading impossible. Therefore, if a non-porous metal plate or the like is used as a reinforcing plate and integrally molded with the plus deck, there is a problem in that the pickup body becomes heavy.

The present invention was made in view of the above circumstances, and includes an optical system,
The pickup body that houses the actuator etc. can be molded with plus deck Wffi and high strength,
It is an object of the present invention to provide an optical pickup that is less deformed and can maintain the accuracy of the optical system.

[Means and operations for solving the problems] In order to solve the above problems, the present invention irradiates the recording surface of a recording medium with light emitted from a light source, and guides the reflected light to a photodetector. An optical pickup that includes an optical system and an actuator that can control the movement of the optical system relative to a recording surface of a recording medium, and is configured to record and reproduce information, in which the optical system and the actuator are housed. The pickup body is molded from plastic, and a reinforcing member with a large number of holes 61J is integrally molded into the pickup body, resulting in a wide eave, high strength, and less deformation.

[Example] Hereinafter, an example according to the present invention will be specifically described with reference to the drawings.

FIG. 1 and FIG. 2 relate to a first embodiment of the present invention.
The figure is a partially cutaway perspective view of the optical pickup.
The figure is a perspective view of the reinforcing member.

In these figures, the optical pickup has a configuration in which an optical system and the like are housed within a pickup body 21.

The pickup main body 21 is made of a material such as plastic, and is formed in the shape of a rectangular parallelepiped box with an opening at the top. Further, the pickup main body 21 is integrally molded with a reinforcing member 22 made of metal mesh inserted into its side wall. A light source 23 is fixed to one longitudinal side of the pickup body 21, and a collimator lens 24, a polarizing prism 25, and a reflecting prism 26 are arranged on the optical path of the light source 23.
A 174 wavelength plate 27, an objective lens 28, etc. are further arranged in the reflection direction of the reflecting prism 26. This objective lens 28 is held by an arm 29a that extends laterally from the upper surface of the two actuators.

A cover 30 is attached to the upper frontage of the pickup main body 21, and a long hole 30a for moving the objective lens 28 forward is bored in the cover 30.

This elongated hole 30a is used for the movement of the objective lens 28 during tracking operation. This allows JJ Ei. Further, a critical angle prism 31 is fixed to the polarizing prism 25,
Further, the reflection direction of this critical angle prism 31 (cover 30
A photodetector 32 is arranged on the side).

In such a configuration, the pickup body 21 is integrally molded with the metal reinforcing member 22 inserted into the side wall thereof, thereby reinforcing the plastic and reducing mechanical and thermal deformation. Therefore, accurate reading can be performed while maintaining the accuracy of the optical system. Further, since the reinforcing member 22 is formed of a metal mesh having a large number of holes, it is light, and the entire optical pickup can be extended.

FIG. 3 is a perspective view of a reinforcing member according to a second embodiment of the present invention.

In this embodiment, the reinforcing member 41 is made of a metal plate, and this metal plate has a large number of 6-holes 42. . . . and a screw hole 43.43W are formed. Then, this reinforcing member 41 is inserted into the pickup main body made of plastic and integrally molded, as in the above-mentioned Example fh.

In such a configuration, the reinforcing member 41 has a large number of openings 7L 4
2. Since the mounting screw holes 43 and 43 are formed, the plastic can be reinforced and the weight can be reduced.

In the above embodiment, the reinforcing member 22.41 may be made of a material such as metal, has a large number of holes (including a wire mesh shape), and may be integrally formed with the pickup body 21. The rollers may be the only parts that require less deformation or higher strength. In general, the pickup body 21 may have a mounting hole for an optical system, etc., and its shape can be arbitrary.Furthermore, the arrangement and structure of the optical system and actuator 29 are not limited to those in the embodiment.

[Effects of the Invention] As explained above, according to the present invention, the pip body that houses the optical system and the actuator is molded from plastic, and a reinforcing member having a large number of holes is integrally molded in the pickup body. Because of this, it can be molded to be lightweight and strong, with little deformation and the accuracy of the optical system can be maintained.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 relate to a first embodiment of the present invention.
2 is a perspective view of a reinforcing plate portion, FIG. 3 is a perspective view of a reinforcing member according to the second embodiment of the present invention, and FIG. 4 is a conventional example. Regarding the original optical pickup I! T! It is an explanatory diagram. 21...Pickup body 22.41...Reinforcement plate 23...Light source 24...Collimator lens 25...Polarizing prism 26...Reflecting prism 27
...174 wavelength plate 28...Objective lens 29...
・Actuator 31...Critical angle prism 32...Photodetector 42...Opening hole vgi Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) An optical system that irradiates the recording surface of the recording medium with light emitted from a light source and guides the reflected light to a photodetector, and this optical system can be controlled to move relative to the recording surface of the recording medium. In an optical pickup equipped with an actuator for recording and reproducing information, the pickup body housing the optical system and the actuator is molded from plastic, and the pickup body is provided with a reinforcing member having a large number of holes. An optical pickup characterized by being integrally molded. (2) The optical pickup according to claim 1, wherein the reinforcing member having a large number of holes is a metal mesh.