| 摘要 |
PURPOSE:To obtain a compact, thin optical head by changing the optical axis of the light emitted from a semiconductor laser into the direction of the optical axis of an objective lens with a light-amount separating means, and arranging a photodetector on an optical substrate at a position facing the objective lens with the light-amount separating means in-between. CONSTITUTION:A part of the amount of laser light emitted from a semiconductor laser 11 is reflected from a half mirror 12 which is inclined by about 45 degrees with respect to the optical axis. The reflected light is directed toward the direction of the optical axis of an objective lens 13 and reflected from an optical disk. The light is modulated by the amount of light with the pits of the optical disk. The light is cast into the objective lens 13 again and returned into the half mirror 12. A part of the light is transmitted and cast into a photodetector 14 which is attached on an optical substrate 10. Since the optical axis is changed with the half mirror 12 in this way, optical parts such as a rise-up mirror are not required. The photodetector 14 can be directly arranged laterally on the optical substrate in parallel with the objective lens 13. Therefore, the number of the parts can be decreased, and the optical head can be made compact and thin. |
