The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 04, 1983
Filed:
May. 07, 1981
Junichi Suzuki, Kawasaki, JP;
Kenji Shintani, Tokyo, JP;
Sony Corporation, Tokyo, JP;
Abstract
An optical tracking apparatus for tracing a spiral track on a recording disk includes an optical pickup device having a semiconductor laser and a photoelectric conversion element; an arm device pivotally mounted to an arm shaft with the pickup device being mounted to the free end thereof to thereby move substantially along the radial direction of the recording disk; sectorial arm drive coil attached to a rear end portion of the arm device and having a current path loop in parallel with the rotational plane of the arm device; and a pair of stationary magnetic field forming devices, each formed of a respective yoke and permanent magnet assembly, the yokes having respective air gaps in which magnetic fields in opposite directions to each other are formed, the arm drive coil being arranged to move in the air gaps and being supplied with an arm drive signal and a tracking error correction signal for causing the pickup device to trace the track.