JPH11144295A - Optical head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an optical head thinner in the optical head performing a recording or a reproduction with respect to the optical disk espectially housed in a disk cartridge in among verious kinds of optical disks. SOLUTION: A laser unit 14 in which a light source and a light receiving element are integrated, a reflection mirror 13 bending the light emitted from the laser unit 12, a collimating lens 6 converging the outgoing light, a reflection mirror 8 guiding parallel beams to an optical disk 3, an objective lens 9 converging the parallel beams with respect to the disk 3, an actuator 10 driving the objective lens 9 and a diffraction grating 15 guiding a reflected light from the disk 3 to the laser unit 14 while diffracting it are arranged in the inside of a cartridge opening part 4. Thus, the optical head is made thinner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head for recording or reproducing information on or from an optical recording medium such as an optical disk or a magneto-optical disk, and more particularly, to recording or reproducing an optical disk contained in a disk cartridge. Optical head.

[0002]

2. Description of the Related Art The structure of a conventional optical head is shown in FIG. There is a cartridge 1 and a shutter 2 of the cartridge, and there is a space 4 (hereinafter referred to as an opening) with the optical disk 3 generated by opening the shutter 2. The configuration of the optical head includes a semiconductor laser 5 serving as a light source and a collimating lens 6 for converting light emitted from the semiconductor laser 5 into parallel light.
A prism 7, a reflecting mirror 8 for guiding the parallel light to the optical disk 3, an objective lens 9 for condensing the parallel light on the optical disk 3, and an objective lens 9 for focusing and tracking the disk with respect to the disk. It comprises an objective lens actuator 10 to be followed, a condenser lens 11 for detecting light reflected from the optical disk, and a light receiving element 12. Here, the semiconductor laser 5 and the light receiving element 12 serving as a light source are arranged outside the opening of the cartridge. The optical system 18 including the objective lens actuator 10 and the optical components is mounted on or integrated with the transfer unit 17, and moves on the transfer shaft 16 toward the inner and outer circumferences of the optical disc 3.

[0003]

However, if a semiconductor laser or a light receiving element as a light source is arranged outside the opening of the cartridge as in the prior art, a space for preventing contact with the cartridge and a space for adjusting the semiconductor laser are provided. Must be secured. Therefore, when viewed from the optical disk, there is a problem that the thickness h of the optical head (FIG. 4: conventional example) increases. The present invention disposes a semiconductor laser as a light source in the cartridge opening, and arranges all optical head components such as other light receiving elements and optical components such as lenses and prisms, an objective lens actuator, etc. in the cartridge opening. Accordingly, it is an object to reduce the thickness and size of the optical head as if there is no cartridge.

[0004]

According to the present invention, there is provided an optical system comprising a semiconductor laser as a light source, a light receiving element, and optical components such as a prism and a lens in an opening of a cartridge. The objective lens actuator is arranged.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

(Embodiment 1) Embodiment 1 will be described with reference to FIG. A semiconductor laser 5 serving as a light source and light emitted from the semiconductor laser 5 are provided in a space 4 (hereinafter referred to as an opening) between the cartridge 1 and a shutter 2 of the cartridge, and an optical disk 3 generated by opening the shutter 2. Collimating lens 6 that makes the light parallel
A prism 7, a reflecting mirror 8 for guiding the parallel light to the optical disc 3, an objective lens 9 for condensing the parallel light on the optical disc 3, and a focusing direction and a tracking direction for the objective lens with respect to the optical disc. And an objective lens actuator 10 that follows the optical disk, and a condenser lens 11 that collects reflected light from the optical disk on a light receiving element 12. In other words, a light source having the largest dimension in the height direction among the components such as the collimator lens and the prism constituting the normal optical system is disposed in the opening. The optical system 18 including the objective lens actuator 10 and the optical components is mounted on or integrated with the transfer unit 17, and moves on the transfer shaft 16 toward the inner and outer circumferences of the optical disc 3.

(Embodiment 2) Embodiment 2 will be described with reference to FIG. A semiconductor laser 5 serving as a light source; a collimator lens 6 for converting light emitted from the semiconductor laser 5 into parallel light; a prism 7; a reflecting mirror 13 for bending an optical axis of the parallel light; A reflecting mirror 8 for guiding parallel light to the optical disk 3; an objective lens 9 for condensing the parallel light on the optical disk 3; and an objective lens actuator 10 for causing the objective lens to follow the optical disk in a focus direction and a tracking direction.
And a condenser lens 11 for condensing light reflected from the optical disc on a light receiving element 12 and a light receiving element 12 for detecting the reflected light. With the above configuration, the optical head unit including the objective lens actuator 10 and the optical system unit 18 including the optical components is disposed in the cartridge opening 4. The optical head unit is mounted on or integrated with the transfer unit 17 and moves on the transfer shaft 16 toward the inner and outer circumferences of the optical disc 3.

(Embodiment 3) Embodiment 3 will be described with reference to FIG. A laser unit 14 in which a light source and a light receiving element are integrated;
A reflecting mirror 13 for bending the light emitted from the optical disc, a collimating lens 6 for condensing the emitted light, a reflecting mirror 8 for guiding the parallel light to the optical disc 3, and an objective lens for condensing the parallel light to the optical disc 9, an actuator 10 for driving the objective lens in the focus direction and the tracking direction with respect to the optical disc, and a laser unit 14 for diffracting reflected light from the optical disc.
Is arranged. With the above configuration, the optical head unit including the objective lens actuator 10 and the optical system unit 18 including the optical components is disposed in the cartridge opening 4. The optical head unit is mounted on or integrated with the transfer unit 17 and moves on the transfer shaft 16 toward the inner and outer circumferences of the optical disc 3.

[0009]

As is clear from the above embodiments, according to the present invention, by arranging a semiconductor laser as a light source at the cartridge opening, the thickness h of the optical head viewed from the optical disk (FIG. 1) can be made thinner,
In addition, by arranging the optical system unit composed of light receiving elements and optical components such as lenses and prisms and the objective lens actuator in the opening of the cartridge, the optical head can be made thinner and smaller as if there is no cartridge. Can be.

[Brief description of the drawings]

FIG. 1 is a diagram of a first embodiment of the present invention.

FIG. 2 is a diagram of a second embodiment of the present invention.

FIG. 3 is a diagram of a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a conventional optical head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cartridge 2 Shutter 3 Disk 4 Opening 5 Semiconductor laser 6 Collimating lens 7 Prism 8 Reflection mirror 9 Objective lens 10 Objective lens actuator 11 Condensing lens 12 Light receiving element 13 Reflection mirror 14 Laser unit 15 Diffraction grating 16 Transfer shaft 17 Transfer part 18 Optical system

Claims (2)

[Claims] An optical head for recording or reproducing an optical disk incorporated in a cartridge includes a light source, a collimator lens for collimating light from the light source, a reflection mirror for guiding the parallel light to an objective lens, and an optical disk. An objective lens that focuses light on the optical disk, an objective lens actuator that causes the objective lens to follow the optical disk, and a detection unit that detects reflected light from the optical disk. An optical head comprising a light source for an optical head. 2. An optical head for recording or reproducing an optical disk built in a cartridge, comprising: a light source; a collimating lens for condensing light from the light source; a reflecting mirror for guiding the parallel light to an objective lens; An objective lens for condensing light, an objective lens actuator unit for causing the objective lens to follow the optical disk, and a detection unit for detecting reflected light from the optical disk. An optical head comprising a head.