optical head device

Abstract

Abstract PURPOSE:To execute focus control and tracking control, to reduce the size and price of the title device and to improve the reliability of the device by detecting light transmitted through a semitransparent photodetector by the 2nd photodetector through a focus. CONSTITUTION:Light from a semiconductor laser 1 is projected on a disk 6 through a polarized beam splitter 3 and a 1/4 wavelength plate 4. The reflected light is converged by a condenser lens 7 and detected by the semitransparent photodetector 8 and the photodetector 9 which are arranged through a focus face. Thus, differential outputs are detected in respective three divided areas 80-82, 90-92 of the photodetectors 8, 9 and focus control and tracking control can be executed. Thereby, the number of optical parts can be reduced, the size and price can be reduced and the reliability of the device can be improved.

Inventors

• 👤 Hiroaki Yamamoto
• 👤 博昭 山本
• 👤 Yoshikazu Hori
• 👤 義和 堀
• 👤 Akimoto Serizawa
• 👤 晧元 芹澤
• 👤 Makoto Kato
• 👤 誠 加藤

Bibliographic Details