JPS629545A - Optical pickup - Google Patents

Abstract

PURPOSE:To attain long term stability of a semiconductor laser by making an optical pickup main body mounted with a semiconductor laser with a plastic and forming a heat dissipation open hole at least near the part mounting the semiconductor laser. CONSTITUTION:The heat dissipation open hole 1a is formed to the optical pickup main body 1 near the mounting part of the semiconductor laser 2 to the optical pickup main body 1 made of a plastic, the heat dissipation open hole 11a is formed to a cover 11 so as to avoid the heat from the semiconductor laser itself from being kept in the optical pickup. Further, the heat dissipation open hole 10a is formed near a drive coil constituting an actuator 8 so as to avoid the heat from being kept in the pickup. Since the heat dissipating performance of the optical pickup main body 1 made of a plastic is improved sufficiently in this way, the semiconductor laser 2 is used stably for a long time.

Description

[Detailed Description of the Invention] [Industrial Application] The present invention relates to an optical pickup used for, for example, reproducing information recorded on an optical recording disk or recording information on such a disk. be.

[Conventional technology]

Conventionally, a support mechanism that supports an objective lens so as to be movable in a focusing direction parallel to the optical axis and a tracking direction perpendicular to the focusing direction, and a drive mechanism that drives the objective lens in the focusing direction and the tracking direction. The actuator is attached to the optical pickup body, and optical elements such as a semiconductor laser that emits a light beam, a beam splitter, and a photodetector are attached to the optical pickup body, and the light beam from the semiconductor laser is recorded through the objective lens of the actuator. An optical pickup that emits light onto a medium in a spot-like manner has been proposed.

In such an optical pickup, the optical pickup main body is conventionally made of a metal such as die-cast aluminum or die-cast zinc that has good thermal conductivity and therefore has a high heat dissipation effect. However, if the optical pickup body is made of metal in this way, the processing is troublesome, the cost is high, and the weight is also heavy, which is a major obstacle in making the optical pickup smaller, lighter, and lower in cost. .

[Problem that the invention seeks to solve]

Therefore, in order to solve the above problem, the applicant has developed an optical pickup body in which the main body is integrally molded from plastic. However, when the optical pickup main body is made of plastic in this way, there is a problem that the life of the semiconductor laser is shortened because plastic has poor thermal conductivity compared to metal and therefore has a low heat dissipation effect.

This invention was made in view of these problems, and the optical pickup body is made of plastic, and the semiconductor laser mounted thereon is appropriately constructed so that it can be used stably over a long period of time. The purpose is to provide optical pickups.

[Means and effects for solving the problem] In order to achieve the above object, in the present invention, an optical pickup to which an optical element such as a semiconductor laser is mounted is formed of plastic, and at least the vicinity of the part to which the semiconductor laser is mounted is made of plastic. A hole for heat radiation is formed in the optical pickup body to improve the heat radiation performance of the optical pickup body made of plastic.

〔Example〕

The drawings show one embodiment of the invention.

The optical pickup main body l is integrally molded from plastic. This optical pickup main body 1 includes a semiconductor laser 2. Optical elements such as a collimator lens 8, a polarizing prism 4, 14 wavelength plate 5, a reflecting prism 6, and a photodetector (not shown) are attached, as well as an objective lens? A light beam from the semiconductor laser 2 is attached to an actuator 8 having
The reflected light is irradiated onto a recording medium 9 such as an optical disk in a spot shape through an objective lens 7, and the reflected light is transmitted through an objective lens 7, a reflective prism 6, an electric wave plate 5, and a polarizing prism 4.
The structure is such that the light is received by a photodetector after passing through.

The actuator 8 includes a mechanism that supports the objective lens 7 so as to be movable in a focusing direction parallel to the optical axis and a tracking direction perpendicular thereto, and a drive coil for driving the objective lens 7 in the focusing direction and the tracking direction, respectively. A drive mechanism is provided, and the configuration is such that focusing control and tracking control can be performed by passing a required current through each drive coil.

In addition, the area around the actuator 8 is surrounded by a cover 10 except for the optical path in order to prevent dust from entering.
The connecting terminal side of the semiconductor laser 2 exposed to the outside is also surrounded by a cover 11 except for the portion through which the lead wire passes, in order to prevent contact accidents.

In the above configuration, the effects of heat on the semiconductor laser 2 include heat generated by the semiconductor laser itself and heat generated from the drive coil that constitutes the actuator 8. If the optical pickup main body l is made of a metal such as die-cast aluminum, the heat conductivity is good and therefore the heat dissipation effect is high, so this heat generation will not have a negative effect on the semiconductor laser 2. If the semiconductor laser 1 is made of plastic as described above, its thermal conductivity is poor and its heat dissipation effect is low, which causes problems such as heat being trapped inside the optical pickup and shortening the life of the semiconductor laser 2.

Therefore, in this embodiment, a heat dissipation hole 1a is formed in the optical pickup body 1 near the attachment point of the semiconductor laser 2 to the optical pickup body 1, and a heat dissipation hole 11a is also formed in the cover 11. This prevents the heat generated by the semiconductor laser itself from being trapped inside the optical pickup. Further, a heat dissipating hole 10a is formed in a cover 10 surrounding the actuator 8 in a portion close to the drive coil constituting the actuator 8 to prevent the heat generated from being trapped inside the optical pickup.

In this way, the heat dissipation of the optical pickup body 1 made of plastic can be sufficiently improved.
The semiconductor laser 2 can be used stably for a long period of time. Further, since the optical pickup main body l can be obtained by integral molding of plastic, it can be easily manufactured and is extremely advantageous in reducing size, weight, and cost.

In the above-described embodiment, the heat dissipation hole 1a of the optical pickup body 1 made of plastic is connected to the semiconductor laser 2.
Although it is formed only in the vicinity of the attachment part, it may be formed in other parts as well.

〔Effect of the invention〕

As described above, according to the present invention, since the optical pickup main body is made of glass, it can be made smaller, lighter, and lower in cost, and heat can be dissipated at least near the part where the semiconductor laser is mounted on the optical pickup main body. Since the aperture is formed, the semiconductor laser can be used stably for a long period of time.

[Brief explanation of the drawing]

The drawing is a sectional view showing an embodiment of the present invention. l... Optical pickup body 1a... Opening 2... Semiconductor laser 8.
... Collimator lens 4 ... Polarizing prism 5 ...
Wave plate 4 6...Reflecting prism? ...Objective lens 8...Actuator 9...Recording medium 10, 11...Cover 10a, ll
a - Open hole

Claims (1)

[Claims] 1. In an optical pickup equipped with an optical element such as a semiconductor laser, the light beam from the semiconductor laser is projected onto a recording medium in the form of a spot through an objective lens. 1. An optical pickup characterized in that a pickup body is made of plastic, and a hole for heat dissipation is formed at least in the vicinity of a portion where the semiconductor laser is mounted.