JPH07296410A - Optical head device on which laser beam is incident through optical fiber - Google Patents

Abstract

PURPOSE:To miniaturize and lighten an optical head by arranging an optical fiber between a light source of an optical head and a collimation lens. CONSTITUTION:An outgoing luminous flux emitted from a light source 1 is converged by a convex lens 3, made incident on an optical fiber 5, transmitted through it, and made incident on an optical head body (movable part) 13. An incident luminous flux from the optical head body 13 is made a parallel luminous flux by the collimation lens 6, after it is transmitted through a beam splitter 7, totally reflected by a total reflection mirror 8, converged by an object lens 9 and focused on an optical medium 10. The luminous flux converged on the optical medium 10 is reflected by a recording film, made to be a parallel luminous flux by the object lens 9, separated from an outgoing light by the beam splitter 7 and made a signal luminous flux, focused on a photo-detector 12, and information on the optical medium is read. With this constitution, the light source 1 and its driving circuit section are separated from the optical head body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head device used for recording / reproducing information on an optical medium by a light beam emitted from a light source, and more particularly to let a laser beam enter through an optical fiber. The present invention relates to an optical head device.

[0002]

2. Description of the Related Art A conventional optical head structure is shown in FIG. In the figure, an outgoing light beam emitted from a light source 1 such as a semiconductor laser is converted into a parallel light beam by a collimating lens 6 placed at a position of a focal length from the light source, transmitted through a beam splitter 7, and then totally reflected by a total reflection mirror 8. Is focused by the objective lens 9 and focused on the recording film on the optical medium 10. The light beam condensed on the optical medium 10 is reflected on the recording film, becomes a parallel light beam again by the objective lens 9, is separated from the emitted light beam by the beam splitter 9 and becomes a signal light beam, and a signal detection lens 11 detects the signal. The information on the optical medium 10 is read by focusing on the photodetector 12 for use. The part other than the optical medium 10 becomes the optical head main body 13 and becomes the movable part.

[0003]

In the conventional optical head having the structure shown in FIG. 2, all parts except the optical medium 10 are movable parts of the optical head.
The weight of the optical head itself increases, and the optical head becomes large. Further, the center points of the light source 1, the collimator lens 6, the beam splitter 7, the total reflection mirror 8 and the objective lens 9 need to be on the optical axis in a straight line.

The object of the present invention is to reduce the weight and size of the head by separating the light source 1 from the movable part, eliminating the need to dispose the light source on the same straight line as other optical parts.
An object of the present invention is to provide an optical head device in which the drive circuit of the light source can be freely arranged.

[0005]

According to the present invention, the light source is made to pass through the optical fiber between the light source and the optical head main body, and to make the light beam passing through the inside of the optical fiber enter the optical head main body. By separating the optical parts from the optical parts, it is possible to obtain an optical head device in which a laser beam that allows the movable part of the optical head to be made smaller and lighter and the position of the light source part to be freely arranged is incident through an optical fiber.

[0006]

FIG. 1 shows an embodiment of the present invention.

In FIG. 1, two convex lenses 2 and 3 are arranged in front of the light source 1, an optical fiber 5 is arranged between the convex lens 3 and the collimating lens 6, and the optical head is fixed to the light source side fixing portion 4. And the optical head body (movable part) 13 are separated.

In the above structure, the light flux emitted from the light source 1 becomes a parallel light flux by the convex lens 2, is focused by the convex lens 3, and is incident on one end face of the optical fiber 5 arranged near the focal length. The light that has entered the optical fiber 5 propagates through the fiber, emits a light beam from the end face on the opposite side to the incident side, and the optical head main body 13
Incident on. The light flux incident on the main body becomes a parallel light flux by the collimator lens 6 placed at the position of the focal length from the end face of the optical fiber 5 which is the incident point of the light flux, and passes through the beam splitter 7, as in the conventional device FIG. The light is totally reflected by the rear total reflection mirror 8, condensed by the objective lens 9, and focused on the recording film on the optical medium 10.

The light beam condensed on the optical medium 10 is reflected on the recording film, becomes a parallel light beam again by the objective lens 9, is separated from the emitted light beam by the beam splitter 9, and becomes a signal light beam. Is focused on the photodetector 12 for signal detection by the optical medium 10
Read the information above. The light source 1 and the two convex lenses 2 and 3 become the optical head fixing portion 4, and the collimator lens 6, the beam splitter 7, the total reflection mirror 8, the objective lens 9, the signal condensing lens 11, and the photodetector 12 are the optical head main body 1
It becomes 3 and becomes a movable part.

[0010]

According to the present invention, an optical fiber is provided between the light source of the optical head and the collimating lens,
Since the light source and its drive circuit section are separated from the main body of the optical head, only the optical fiber which is smaller and lighter than the light source and only the end face enter the movable section, so that the optical head can be made smaller and lighter.

Further, since the positional relationship between the light source and the head main body is free, there is no limitation on the arrangement of the light source section, and the space of the device can be effectively used.

Further, in the case of an apparatus using a plurality of optical heads, it is possible to collectively arrange as many light sources as there are to be used at one place.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an optical head as a conventional example.

[Explanation of symbols]

 1 Light source 1 2 Convex lens 3 Convex lens 4 Optical head fixing part 5 Optical fiber 6 Collimating lens 7 Beam splitter 8 Total reflection mirror 9 Objective lens 10 Optical medium 11 Signal condensing lens 12 Photodetector 13 Optical head body (movable part)

Claims (2)

[Claims] 1. In an optical head device for condensing a light beam on an optical medium to reproduce information from the medium or record information on the medium, a light beam from a light source is converted into an optical fiber by using a convex lens. An optical head device for injecting laser light through an optical fiber, characterized in that a light beam is made incident on the end face of the optical head, and a light flux is made incident on the main body of the optical head from the opposite end face through the optical fiber. 2. An optical head fixing part including a laser light source and a lens for receiving the laser light from the light source, an optical fiber for guiding the laser light from the optical head fixing part, and a beam for receiving the laser light guided by the optical fiber. A laser beam having a splitter and an optical system for guiding the light passing through the beam splitter to an optical medium and an optical head fixing unit including a photodetector for detecting reflected light from the optical medium through the beam splitter is made to enter through an optical fiber. Optical head device.