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, 2005
Filed:
Sep. 28, 2001
Applicants:
Akihiro Yasuda, Katano, JP;
Kazuhiro Hayashi, Kadoma, JP;
Daisuke Ogata, Amagasaki, JP;
Inventors:
Assignee:
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B007/24 ;
U.S. Cl.
CPC ...
Abstract
An optical information recording medium in which the ranges of the refractive index and thickness of a protective layer in a case where the protective layer is constituted by a plurality of layers are newly specified and the refractive index and thickness of the protective layer are determine in these ranges, thereby ensuring that even if variation in thickness of the protective layer to ±3 μm is tolerated, spherical aberration in the optical information recording medium is substantially to within 30 mλrms.