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:
Sep. 04, 2012
Filed:
Feb. 10, 2010
Fumiaki Nakano, Tokyo, JP;
Nobuhiko Ando, Tokyo, JP;
Noriaki Nishi, Kanagawa, JP;
Takashi Nakao, Tokyo, JP;
Hiroaki Nakagawa, Tokyo, JP;
Yutaka Tentaku, Tokyo, JP;
Fumiaki Nakano, Tokyo, JP;
Nobuhiko Ando, Tokyo, JP;
Noriaki Nishi, Kanagawa, JP;
Takashi Nakao, Tokyo, JP;
Hiroaki Nakagawa, Tokyo, JP;
Yutaka Tentaku, Tokyo, JP;
Sony Corporation, Tokyo, JP;
Abstract
An optical pickup includes: a light source outputting a light beam; an objective lens collecting the light beam on a target recording layer as a target of plural recording layers provided in an optical disc; a lens moving unit moving the objective lens in a tracking direction nearly orthogonal to track grooves helically or coaxially formed in the target recording layer; a collective lens collecting a reflected light beam formed when the light beam is reflected by the optical disc; a diffraction optical element diffracting part of the reflected first-order light beam in predetermined directions as first, second, third and fourth beams; and a photodetector receiving the first and second beams using first and second light receiving areas, and generating light reception signals, and receiving the third and fourth beams using third and fourth light receiving areas, and generates light reception signals.