Optical head

Abstract

Abstract PURPOSE:To eliminate the return light of a semiconductor laser and to ensure the stable oscillation of the semiconductor laser, by making the light radiated from the semiconductor laser incident on the surface of an optical recording medium from a tilted direction and receiving the reflected light by a photodetector set at the single side of the semiconductor laser. CONSTITUTION:The light 25 radiated from a radiating end surface 14a of a semiconductor laser 14 is made incident in the direction tilted in the track width direction by an angle theta against the direction vertical to an optical recording medium surface 28. Then the light 26 reflected by the track guide grooves (not shown where) formed continuously in the direction vertical to the surface 28 does not virtually return to the surface 14a and goes to the detecting surfaces of photodetectors 16a and 16b. The bias voltage is applied to both electrodes 18a and 18b for photodetectors set on the surfaces of both photodetectors 16a and 16b in the direction opposite to a common electrode 19. Therefore, the reflected light 26 is received by photodetectors 16a and 16b and a track signal can be obtained by the difference signal of output between both photodetectors 16a and 16b.

Inventors

• 👤 Yoshinori Isomura
• 👤 磯村　嘉伯
• 👤 Hiroo Ukita
• 👤 宏生 浮田

Bibliographic Details