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. 14, 1987
Filed:
Oct. 18, 1984
Shinsaku Nozu, Tokorozawa, JP;
Katsuharu Sato, Tokorozawa, JP;
Hozumi Tanaka, Tokorozawa, JP;
Kenjiro Hamanaka, Tokorozawa, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Abstract
A focus error detection device to be used in an optical system for recording and/or playing back information, including a light detector made up of four light receiving elements arranged symmetrically with respect to the center of the light detector, a first operation circuit means connected to the light receiving elements for generating a focus error signal, and a second operation circuit means also connected to the light receiving elements for generating an off-set compensation signal. With this construction, and off-set of the focus error signal due to the deviation of the position of the reflection light beam is by far reduced as compared with the conventional devices.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile