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. 15, 1985
Filed:
Jan. 19, 1982
Applicant:
Inventors:
Toshio Sugiyama, Toyokawa, JP;
Yoshio Yamane, Yokohama, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 44 ; 2502 / ; 369 45 ;
Abstract
An optical scanning device for subjecting a light spot to a focussing operation and for causing the light spot to perform a tracking operation to reproduce information stored in a video or audio disc is disclosed in which a coil controlling a focussing optical system for forming the light spot and another coil causing the light spot to track the above-mentioned information are both placed in a magnetic gap included in a magnetic circuit formed by a permanent magnet and a magnetic member, and the magnetic circuit is arranged in a direction perpendicular to the direction of the tracking operation.