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. 25, 2011
Filed:
May. 29, 2008
Eishin Mori, Kyoto, JP;
Kousei Sano, Osaka, JP;
Joji Anzai, Osaka, JP;
Hideki Aikoh, Osaka, JP;
Panasonic Corporation, Osaka, JP;
Abstract
An object of the invention is to suppress an influence of a wavefront aberration which is generated at the time of correcting a third-order spherical aberration, and realize satisfactory information recording and/or reproducing. A collimator lenscorrects a third-order spherical aberration which is generated depending on the thickness of a light transmissive layer from a surface of a first optical information recording medium, corresponding to an optimal substrate thickness of a first objective lens, to an intended information recording surface, assuming that the light transmissive layer thickness of the first optical information recording mediumwhich minimizes a residual third-order spherical aberration at the time of incidence of parallel light into the first objective lensis defined as the optimal substrate thickness of the first objective lens. The optimal substrate thickness of the first objective lensis defined in such a manner that a variation of a wavefront aberration which is generated on the information recording surface of the first optical information recording mediumfarthest from the first objective lensat the time of correcting the third-order spherical aberration, and a variation of a wavefront aberration which is generated on the information recording surface of the first optical information recording mediumclosest to the first objective lensat the time of correcting the third-order spherical aberration are set equal to each other.