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:
Aug. 14, 2001
Filed:
Apr. 23, 1998
Takayuki Nagata, Hirakata, JP;
Akihiro Arai, Soraku-gun, JP;
Toru Nakamura, Katano, JP;
Takao Hayashi, Toyonaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An optical head comprises a photodetector,having divided photosensitive areas to detect light,reflected from an optical disk,means,for obtaining track error signal by operating signals from the photosensitive areas. The photodetector,has a first division line,parallel to an information track on the optical disk and second and third division lines,perpendicular to the first division line,and symmetrical to the optical axis. Further, a light-shielding area,is provided for shielding a part of the reflected light between the division lines,and,. The signals are operated to reduce offset of the tracking error signal due to a shift of object lens and a tilt of the optical disk. Accordingly, the optical head of the present invention has a small offset of tracking error signal with a simple structure.