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. 26, 2009
Filed:
Aug. 04, 2006
Tatsuya Nakamori, Okayama, JP;
Masayuki Ono, Osaka, JP;
Naoki Nakanishi, Shiga, JP;
Masahiko Nishimoto, Osaka, JP;
Tatsuya Nakamori, Okayama, JP;
Masayuki Ono, Osaka, JP;
Naoki Nakanishi, Shiga, JP;
Masahiko Nishimoto, Osaka, JP;
Panasonic Corporation, Osaka, JP;
Abstract
An optical pickup has a semiconductor laser, a diffractive optical element that has first diffraction regions and second diffraction regions and diffracts a beam emitted by the semiconductor laser, an objective lens that focuses the diffracted beam on an optical disc, and a detection unit that detects a tracking error signal using the diffracted beam reflected by the optical disc. When a zero order diffraction beam is focused on the optical disc, a first order diffraction beam is diffracted by the first diffraction regions to be focused at a position between the objective lens and the optical disc, and diffracted by the second diffraction regions to be focused at a position beyond the optical disc. The first order diffraction beam has a beam width that, on the optical disc in a radial direction thereof, is two times or greater a track pitch of the optical disc.