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. 10, 2010
Filed:
Apr. 11, 2006
Fumitomo Yamasaki, Nara, JP;
Eishin Mori, Kyoto, JP;
Hideki Aikoh, Osaka, JP;
Akihiro Arai, Kyoto, JP;
Joji Anzai, Osaka, JP;
Fumitomo Yamasaki, Nara, JP;
Eishin Mori, Kyoto, JP;
Hideki Aikoh, Osaka, JP;
Akihiro Arai, Kyoto, JP;
Joji Anzai, Osaka, JP;
Panasonic Corporation, Osaka, JP;
Abstract
Fifth order spherical aberration in addition to third order spherical aberration for an optical information recording medium of which thickness of a light transmission layer changes greatly is corrected. An objective lens collects a laser beam emitted from a semiconductor laser on an optical information recording medium. A spherical aberration correcting portion corrects spherical aberration generated according to a thickness of the light transmission layer of the optical information recording medium, in which the spherical aberration correcting portion includes a collimator lens, a lens holder and a stepping motor for correcting the third order spherical aberration and a liquid crystal element and an applied voltage control portion for correcting the fifth order spherical aberration.