Pickup device of optical disc

Abstract

Abstract PURPOSE:To attain the prevention of deterioration in a reproducing characteristic caused by the effect of skew by providing an exclusive optical means detecting the tilt of the optical disc, forming a skew servo controlling the attitude of the optical system constituting the pickup by means of its detecting value and correcting an error of a skew detecting point altogether. CONSTITUTION:A light irraidated from a light irradiating source 10 provided to a skew device SD is formed into nealy parallel ray by a lens system 11 and irradiated onto an optical disc D via a polarized beam splitter (PBS)12 and a 1/4lambda plate (QWP)13 for detecting skew. Then, the reflected light reflected from the recording face of the optical disc D is reflected nearly at a right angle by the PBS12 via the QWP13 and detected by a photodetector 14. In splitting the photodetector into four parts and operating the signals obtained from each split photodetector, the tilt of the optical disc D is detected. The signal detected by the photodetector 14 is applied to an operating circuit and a driver circuit or the like, a small sized motor or the like tilts the pickup device and controls so that the optical axis is made perpendicular to the recording face of the optical disc.

Inventors

• 👤 Akio Koizumi
• 👤 明夫 小泉

Bibliographic Details