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, 2011
Filed:
Mar. 19, 2007
Seiji Nishiwaki, Hyogo, JP;
Kazuo Momoo, Osaka, JP;
Junichi Asada, Hyogo, JP;
Panasonic Corporation, Osaka, JP;
Abstract
Light emitted from a radiation light sourcepasses through a diffraction gratingand is separated into transmitted light a and +1st/−1st order diffracted lights b, c. These lights are collected through an objective lenson tracks of an optical discin a partially overlapped state. Light reflected by the tracks passes through the objective lensand is incident upon light diverging means. Subsequently, light corresponding to the transmitted light 'a' diverges into two light beams that are respectively incident upon light detection regions A, A, light corresponding to the diffracted lights 'b' and “c” respectively diverges into two light beams that are respectively incident upon light detection regions B, B, and C, C. A tracking error signal associated with the tracks of the optical discis generated by combining signals detected in the light detection regions A, A, B, B, C, and C