Optical pickup

Abstract

Abstract PURPOSE:To simplify the adjustment, to attain cost reduction, small size and light weight by providing a diffraction grating dividing a laser beam into three light beams, a hologram comprising two regions, and a six-split photodetector arranged to the hologram in the direction of diffracted light thereby simplifying the optical system. CONSTITUTION:A light beam radiated from a laser light source 1 is divided into three light beams by a diffraction grating 2, transmits through a hologram 10, is collected by an objective lens 5 to form a light spot on a disk signal face. The returned light reflected on the disk signal face traces the same optical path, is made incident on the hologram 10, diffracted at a prescribed angle by the hologram 10 and a light spot is formed on the six-split photodetector 11 arranged in the diffraction direction. The six-split photodetector 11 detects the light spot to detect a focusing error, a tracking error and a reproducing signal. Thus, the optical system is remarkably simplified in comparison with a conventional three-beam optical pickup, the cost is reduced and small size/light weight is attained and the adjustment is simplified.

Inventors

• 👤 Shiyuuichi Onayama
• 👤 Kazuhiko Nosaka

Bibliographic Details