JPH0521706Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an optical pick-up head device such as an optical pick-up head that optically reads information from a digital audio disk, and in particular uses a housing that prevents static electricity. This invention relates to an optical pick-up head device.

[Technical background of the invention and its problems]

Conventionally, an optical pick-up head is an optical device using a semiconductor laser. This optical pick-up head optically processes the light emitted from a semiconductor laser using an optical system, focuses the light beam onto the digital audio disk surface using an objective lens, and collects the optical signal reflected from this digital audio disk surface. is converted into an electrical signal using a photodiode. The semiconductor laser, optical system, etc. are provided in the housing body and covered with a cover.

However, because the housing, consisting of the housing body and cover, is formed from a non-conductive plastic, the housing is charged with static electricity during use of the optical pickup head. Due to the static electricity charged in the housing, there was a risk that the semiconductor laser's light emitting characteristics would deteriorate or electrostatic damage would occur. Generally, the light emitting characteristics of a semiconductor laser deteriorate at a voltage of several tens of volts.

[Purpose of invention]

This idea was made in view of the above circumstances.
By preventing the housing of an optical pickup head that includes a semiconductor laser from being charged with static electricity, it is possible to prevent the emission characteristics of the semiconductor laser from deteriorating due to the static electricity charged in the housing, and also to prevent electrostatic damage from occurring. It is an object of the present invention to provide an optical pick-up head device that can prevent

[Summary of the idea]

The optical pick-up head device of the present invention is characterized in that the components of the optical pick-up head including the semiconductor laser are assembled in a housing made of conductive plastic or non-conductive plastic whose surface is coated with conductive paint. .

[Example of idea]

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

1 and 2a and 2b show an example of an optical pickup head. That is, the semiconductor laser 1
The substantially linearly polarized light beam emitted from the beam enters the diffraction grating 2, is split into 0th-order and ±1st-order light beams, is transmitted through the polarization beam splitter 3, and is turned into parallel light by the collimating lens 4. The optical path of these three parallel lights is changed to a right angle by a prism mirror 5, and the light passes through a quarter-wave plate 6, becomes circularly polarized, and enters an objective lens 7. The light emitted from the objective lens 7 is converged on the information recording surface of the digital audio disk 8 to form three minute spots. Each light beam reflected from the information recording surface of the disk 8 travels in the opposite direction, passing through the 1/4 wavelength plate 6.
By means of the polarizing beam splitter 3 and the polarizing beam splitter 3, most of the light beam passes through a collimating lens 4 and an astigmatism optical system 9 formed of a cylindrical lens and a concave lens, and enters a photodetector 10, which is a photodiode. An information signal is extracted from the output of this photodetector 10. The semiconductor laser 1, the diffraction grating 2, the polarizing beam splitter 3, the collimating lens 4, the prism mirror 5, the 1/4 wavelength plate 6, the objective lens 7, etc. are provided in a housing body 11 and covered with a cover 12. An opening 13 is provided in a portion of the cover 12 that corresponds to the objective lens 7. The cover 12
The housing body 11 is made of conductive plastic. As the conductive plastic, for example, plastic mixed with carbon powder or metal powder can be used.

Note that the cover 12 and the housing body 11
may be made of non-conductive plastic, and its surface may be coated with a conductive paint to make it conductive.

In this way, the housing consisting of the housing body 11 and the cover 12 into which the components of the optical pickup head including the semiconductor laser 1 are assembled can be made of conductive plastic, or it can be made of non-conductive plastic and then coated with conductive paint. By providing electrical conductivity, such as coating, the housing will not be charged with static electricity during use of the optical pickup head. Therefore, it is possible to prevent deterioration of the light emitting characteristics of the semiconductor laser and electrostatic damage caused by electrostatic charge on the housing. Furthermore, since the housing is made of conductive plastic or non-conductive plastic whose surface is coated with conductive paint, it is lighter than a case where the entire housing is made of metal, and can also be expected to have a vibration absorption effect. The light weight of the housing and its vibration-absorbing properties are significant advantages, especially in optical pickup heads built into portable CD players and the like.

[Effect of idea]

As described above, according to the present invention, the components of an optical pick-up head including a semiconductor laser are assembled into a housing made of conductive plastic or non-conductive plastic whose surface is coated with conductive paint. It is possible to prevent the light emitting characteristics from deteriorating due to static electricity and the semiconductor laser from being damaged by static electricity.

Furthermore, since the housing can be made lighter than when it is made of a metal material, it is possible to suppress an increase in the weight of the entire pickup head. As a result, the linear actuator for moving the pick up head in the radial direction of the disk can be a small, lightweight motor with low torque, making the entire device including the pick up head and linear actuator smaller and lighter. can do.

Furthermore, if the housing is made of plastic, the housing can have a vibration absorbing effect, so the components of the pickup head can be protected from vibrations and shocks, and the operation can be stabilized.

Therefore, the optical pick-up head device of the present invention is suitable for portable equipment that is required to be small, lightweight, and resistant to vibrations and shocks.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram showing an example of an optical system of an optical pick-up head device according to the present invention, FIG. 2 a is a top view showing an embodiment of the present invention, and FIG. 2 b is a sectional view of the same. . 1... Semiconductor laser, 2... Diffraction grating, 3...
Polarizing beam splitter, 4... Collimating lens, 5... Prism mirror, 6... 1/4 wavelength plate,
7...Objective lens, 8...Digital audio disk, 9...Astigmatism optical system, 10...Photodetector, 11...Housing body, 12...Cover.

Claims (1)

[Scope of utility model registration request] 1. An optical pick-up head device characterized in that components of the optical pick-up head including a semiconductor laser are assembled in a housing made of conductive plastic or non-conductive plastic whose surface is coated with conductive paint.