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. 18, 1988
Filed:
May. 08, 1986
Toshio Sugiyama, Aichi, JP;
Hideo Suenaga, Toyokawa, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An optical reading/reproducing apparatus such as a compact disc (CD) player, and particularly a focusing system therefor, wherein the direction of one of the focal lines of the light spot on a light detector is set to be in parallel with the direction of track on the disc surface, a divide-into-four line of the light detector is set to be 45 degrees or a value close thereto with respect to the track direction, and an offset voltage is applied to a portion of the focus servo loop connected with the output unit of a focus error detector circuit. Owing to this structure, the optical parts can be easily mounted, a casing for containing them can be easily molded, and the apparatus can be mass-produced in small sizes.