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:
Jan. 31, 2012
Filed:
Jun. 01, 2009
Applicant:
Shigeharu Kimura, Yokohama, JP;
Inventor:
Shigeharu Kimura, Yokohama, JP;
Assignee:
Hitachi Media Electronics Co., Ltd., Iwate-Ken, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B 7/135 (2006.01);
U.S. Cl.
CPC ...
Abstract
An optical pickup apparatus for use on multi-layered optical information storage medium in which influences of reflected light, which result in crosstalk from adjacent layers in a multi-layered optical disk, are mitigated. In an astigmatic optical system of the optical pickup, a first composite segmented wave plate having a segmentation direction that is in the same direction as the focal line that is close to the astigmatic optical system, a second composite segmented wave plate of the same segmentation direction, and an analyzer are inserted.