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:
Apr. 19, 2011
Filed:
Dec. 06, 2006
Applicants:
Hiroaki Matsumiya, Osaka, JP;
Seiji Nishiwaki, Hyogo, JP;
Inventors:
Hiroaki Matsumiya, Osaka, JP;
Seiji Nishiwaki, Hyogo, JP;
Assignee:
Panasonic Corporation, Osaka, JP;
Primary Examiner:
Int. Cl.
CPC ...
G11B 7/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
A focus error signal is generated by a first-order diffracted light diffracted by regionson a hologram plane, and an offset of a tracking error signal is canceled by first-order diffracted light diffracted by regionson the hologram plane. Consequently, even when there is an error in the substrate thicknesses of optical discs, jitter of a reproduction signal at a focus control point can be reduced by decreasing the distance between the focus control point and the point where the jitter is minimized.