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:
Apr. 21, 1987
Filed:
Sep. 06, 1983
Yoshikazu Fujii, Nara, JP;
Toshihisa Deguchi, Nara, JP;
Tetsuya Inui, Nara, JP;
Hideyoshi Yamaoka, Matsubara, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
Disclosed below is a control device for positioning an optical focus in an optical disc apparatus that records, plays back, and erases any information by irradiating optical beams such as the laser beams onto a recording media composed of magnetic film, wherein the control device is characterized in that; it incorporates a focussing permanent magnet that makes up a closed magnetic circuit, a focussing yoke plate, a focussing yoke, and a focussing device coil installed so that it crosses a focussing magnetic space existing that exists between the focussing yoke plate and the focussing yoke so that the focussing magnetic space can be created in an area close to the recording media which is installed in the closed magnetic circuit. In addition, the optical focus position control device that executes both the tracking and focussing control operations for the optical disc apparatus also includes mechanism that drives the objective lens in the direction of dual axes, i.e., in the vertical (up/down) and horizontal (left/right) directions.