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. 05, 2010
Filed:
Aug. 08, 2008
Osamu Miyazaki, Mihara, JP;
Osamu Miyazaki, Mihara, JP;
Sharp Kabushiki Kaisha, Osaka-shi, JP;
Abstract
An optical pickup apparatus and a drive apparatus having the same are provided. Second light-receiving elements or third light-receiving elements for receiving ±first-order diffraction light beams from a polarization hologram are arranged outwardly of a circular region having the optical axis of a zero-order diffraction light beam on a light detector as its center, a radius of which is expressed by (2×t/n)×(f/f), where fdenotes a focal length of an objective lens, fdenotes a focal length of a coupling lens, t denotes a maximum value of a light transmitting layer thickness, n denotes a refractive index of a light transmitting layer.