Optical pickup

Abstract

Abstract PURPOSE:To obtain an optical pickup that generates no noise by permitting a semiconductor laser to oscillate infixed multiplex longitudinal mode. CONSTITUTION:Semiconductor laser 1 is driven by electric current supplied from two electric power sources, DC electric power source 5 and high-frequency current source 6, to provide multiplex longitudinal mode oscillation and laser light that corresponds to the oscillation spectrum focuses on video disk 2 through condenser lenses 41 and 42 to pick up information on disk 2. Through this multiplex longitudinal mode oscillation, a light output varies smoothly against displacement due to the flopping of disk 2 and fluctuations of the light output in which the displacement of disk 2 happens at intervals of lambda/2 are suppressed, suppressing a low frequency range noise perfectly. Here, lambda represents the wavelength of the laser light. Simultaneously, the high-frequency driving multiplex longitudinal mode oscillation reduces the video noise level, so that an optical pickup can be obtained which generates no noise.

Inventors

• 👤 Kunio Aiki
• 👤 Masahiro Oshima

Bibliographic Details