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:
Feb. 20, 2007
Filed:
Mar. 21, 2005
Norio Fukasawa, Kanagawa, JP;
Junichi Suzuki, Kanagawa, JP;
Tetsu Tanaka, Tokyo, JP;
Takeshi Kubo, Kanagawa, JP;
Norio Fukasawa, Kanagawa, JP;
Junichi Suzuki, Kanagawa, JP;
Tetsu Tanaka, Tokyo, JP;
Takeshi Kubo, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
This invention is an optical pickup device having a composite optical element () which has a first diffraction grating () for splitting a light beam emitted from a light source () into zeroth-order light, plus-first-order light and minus-first-order light, a second diffraction grating () for diffracting the optical path of a return light beam from an optical disc (), and a split prism () arranged at a position where the minus-first-order light diffracted by the second diffraction grating () is incident and adapted for splitting the minus-first-order light into a plurality of light beams. It also has a light receiving unit () for acquiring a focusing error signal FE by receiving each return light beam split by the split prism () and for acquiring a tracking error signal by receiving return light beams from the optical disc () of the plus-first-order light and the minus-first-order light split by the first diffraction grating ().