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:
May. 29, 2012
Filed:
Aug. 24, 2009
Applicant:
Tetsuya Nishiyama, Tokyo, JP;
Inventor:
Tetsuya Nishiyama, Tokyo, JP;
Assignee:
TDK, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B 7/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
An optical drive device generates a first push-pull signal and a first sum signal based on a light receiving amount in two light receiving areas of which each width in a signal light tangent direction is smaller than a diameter of a spot of signal light, generates a first normalized push-pull signal by normalizing the first push-pull signal by using the first sum signal, and generates a tracking error signal based on the first normalized push-pull signal.