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. 24, 2000
Filed:
Dec. 29, 1999
Yoichi Tsuchiya, Hashima, JP;
Seiji Kajiyama, Ibi-gun, JP;
Yasuyuki Kanou, Hashima, JP;
Shuichi Ichiura, Hahima, JP;
Sanyo Electric Co., Ltd., Osaka, JP;
Abstract
An optical disc reproducing apparatus includes a semiconductor laser, an objective lens converging a laser beam from the semiconductor laser on a recording surface of an optical disc, a polarization plane rotating unit selectively rotating the plane of polarization of the laser beam according to the thickness of a substrate of the optical disc, and a polarizing filter selectively shading a peripheral portion of the laser beam having the rotated plane of polarization. In one embodiment, a numerical aperture changing unit includes a non-patterned twisted nematic liquid crystal, and the polarizing filter includes a polarizing film having a polarization characteristics at its peripheral portion.