JPH04206051A - Optical head - Google Patents

Abstract

PURPOSE:To form a thin optical head by arranging a semiconductor laser so that the angle formed between the optical axis of the light emitted from the semiconductor laser on a mirror and the optical axis directed toward an objective lens is smaller than 90 degrees. CONSTITUTION:The angle formed between the optical axis of the light which is emitted from a semiconductor laser 11, reflected from a half mirror 15 and directed toward a mirror 14 and the optical axis of the light which is reflected from the mirror 14 and directed toward an objective lens 13 is made to be the angle smaller than 90 degrees. At this time, the attaching position of the semiconductor laser 11 is located at a position close to a light recording medium 12. Furthermore, the light which is reflected from the light recording medium 12 is inclined into the direction of the light recording medium 12 with respect to an optical base 17. The attaching position of a photodetector 16 can be made close to the light recording medium 12. Thus, the thin optical head can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical head used for recording or reproducing optical discs.

2. Description of the Related Art In recent years, optical disks have attracted attention as large-capacity memories, and optical heads used for recording or reproducing the disks are also required to be thinner, and various improvements have been made.

A conventional optical head will be explained below.

FIG. 2 is a configuration diagram of a conventional optical head, in which 1 is a semiconductor laser, 2 is an optical recording medium, 3 is an objective lens for focusing light on the optical recording medium 2, and 4 is the semiconductor laser 1.
5 is a half mirror for separating a part of the reflected light from the optical recording medium 2; 6 is a half mirror for separating a part of the reflected light from the optical recording medium 2; 7 is an optical base on which the optical components described above are assembled.

Problems to be Solved by the Invention However, in the conventional configuration described above, the optical axis of the light emitted from the semiconductor laser 1 is made parallel to the optical recording medium 2;
There was a problem in that there was a limit to achieving a thin structure using conventional parts due to the size of the stem of the semiconductor laser 1 and the shape of the optical transverse ratio device 6.

The present invention solves the above-mentioned conventional problems, and aims to realize an even thinner optical head using parts similar to the conventional ones. In the optical head of the invention, the semiconductor laser is arranged so that the angle between the optical axis emitted from the semiconductor laser and incident on the mirror and the optical axis toward the objective lens is smaller than 90 degrees.

Effect: With this configuration, the center of the semiconductor laser and photodetector can be placed in a direction closer to the optical recording medium with respect to the optical base, making it possible to create an even thinner optical head using the same components as before. Possible 0 Example An example of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of an optical head in an embodiment of the present invention, in which 11 is a semiconductor laser, 12 is an optical recording medium, 13 is an objective lens, 14 is a mirror, and 15Fi half mirror 116
is a photodetector as a detection means, which is the same as the component of the conventional example. In this configuration, the angle between the optical axis of the light emitted from the semiconductor laser 11, reflected by the half mirror 16 and directed toward the mirror 14, and the optical axis of the light reflected by the mirror 14 and directed toward the objective lens 13 is smaller than 90 degrees. It has become. According to this configuration, the mounting position of the semiconductor laser 11 can be placed close to the optical recording medium 12. Furthermore, the light reflected from the optical recording medium 12 is also transferred to the optical base J.
Since it is tilted toward the optical recording medium 12 with respect to L17, the mounting position of the photodetector 16 can also be placed near the optical recording medium 12, and a thinner optical head can be manufactured.

In this embodiment, the ξ sea 14 is tilted to make the optical axis of the light toward the objective lens 13 perpendicular, but the incident surface 16a of the half mirror 16 is tilted to make the optical axis toward the mirror 14 and the optical axis toward the objective lens 13 vertical. The angle formed with the optical axis may be smaller than 90 degrees.

In this case, by changing the angle of the output surface 15b of the half mirror 15, the angle between the optical axis toward the photodetector 16 and the optical axis of the incident light on the objective lens 13 can be made smaller than 90 degrees. Adjust the position of the photodetector 16 to the optical base 17.
It can be installed near the optical recording medium 12.

Effects of the Invention As described above, the present invention improves semiconductor lasers and photodetectors by making the angle between the optical axis of the light toward the objective lens and the optical axis of the light emitted from the semiconductor laser and incident on the mirror smaller than 90 degrees. A thinner optical head can be manufactured without changing the shape of the optical head.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an optical head according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional optical head. 11... Semiconductor laser, 12... Optical recording medium, 13... River objective lens, 14... River ε-ji.
115...Seal/Half Baller, 15! L: half incidence surface, human incidence surface, 15b: half epsilon exit surface, 16: mark/photodetector, 17: optical base. Name of agent: Patent attorney Akira Okaji and two others Figure 1 15 - Half mirror Figure 2

Claims (1)

[Claims] a semiconductor laser, a mirror that reflects light emitted from the semiconductor laser onto an objective lens, and an objective lens that is driven in a focusing direction and a tracking direction to focus the light reflected by the mirror onto an optical recording medium; a detection means for detecting the light reflected from the optical recording medium, and the semiconductor laser is arranged so that the angle between the optical axis toward the objective lens and the optical axis emitted from the semiconductor laser and incident on the mirror is smaller than 90 degrees. An optical head characterized in that it is installed.