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. 26, 2008
Filed:
Apr. 25, 2005
Applicant:
Koichiro Nishikawa, Takasaki, JP;
Inventor:
Koichiro Nishikawa, Takasaki, JP;
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B 7/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
Provided is an optical pickup apparatus which has a function for correcting spherical aberration caused by a thickness error of a transparent substrate and which is sufficiently compact, wherein a collimator lens used in the apparatus is composed of two lens groups, an interval between the two lens groups is changeable, and therefore spherical aberration caused by the thickness error of the transparent substrate is corrected.