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:
Mar. 23, 2010
Filed:
Jul. 31, 2006
Kazunori Matsubara, Shiki-gun, JP;
Shinzoh Murakami, Kitakatsuragi-gun, JP;
Tetsuo Ueyama, Nara, JP;
Kazuhiro Tsuchida, Higashihiroshima, JP;
Yukio Watanabe, Uji, JP;
Osamu Miyazaki, Soraku-gun, JP;
Kazunori Matsubara, Shiki-gun, JP;
Shinzoh Murakami, Kitakatsuragi-gun, JP;
Tetsuo Ueyama, Nara, JP;
Kazuhiro Tsuchida, Higashihiroshima, JP;
Yukio Watanabe, Uji, JP;
Osamu Miyazaki, Soraku-gun, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
There is provided an optical pickup apparatus that can obtain a stable servo signal by reducing stray light generated by diffraction in a recording layer other than a recording layer on which light is condensed. A hologram element provided in an optical pickup apparatus for recording information onto a recording medium and/or reproducing information on the recording medium by use of light includes fourth and fifth divisions where at least first-order diffracted light among diffracted light beams obtained by reflection and diffraction on a recording layer other than a light-condensed recording layer on which light is condensed by an objective lens so as not to be directed toward first and second light-receiving elements for detecting focus position information and third to eighth light-receiving elements for detecting track position information.