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:
Mar. 16, 1993
Filed:
Aug. 05, 1991
Katsushide Tanoshima, Tokyo, JP;
Minoru Ohtsuka, Tokyo, JP;
Shizuo Nagata, Tokyo, JP;
Masahiro Takahashi, Tokyo, JP;
Yasuo Shimizu, Tokyo, JP;
Oki Electric Industry Co., Ltd., Tokyo, JP;
Abstract
In an optical head apparatus for recording or reproducing information onto or from an optical disc, a carriage is movable along a guide shaft extending in a direction parallel with the radial direction of the optical disc, and an armature is mounted on the carriage so that it can rotate about a pivotal axis perpendicular to the surface of the optical disc. An objective lens is fixed to the armature and positioned to traverse the tracks on the optical disc when the armature rotates. Guide yokes extend in parallel with the guide shaft. Tracking and carriage-servo coils are fixed to the armature and have a hollow through which the guide yokes loosely extend. A magnetic field means creates magnetic lines of force perpendicular to the longitudinal direction of the guide yokes and parallel with the surface of the optical disc. A drive circuit supplies currents to the tracking and carriage-servo coils in such directions as to produce electromagnetic forces in parallel with each other thereby driving the armature along the guide yokes or in such directions as to produce electromagnetic forces in antiparallel with each other to rotate the armature about the pivotal axis.