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:
Dec. 17, 2013
Filed:
Sep. 29, 2011
Katsuhiko Hayashi, Nara, JP;
Yoshiaki Komma, Osaka, JP;
Yasuhiro Tanaka, Hyogo, JP;
Michihiro Yamagata, Osaka, JP;
Katsuhiko Hayashi, Nara, JP;
Yoshiaki Komma, Osaka, JP;
Yasuhiro Tanaka, Hyogo, JP;
Michihiro Yamagata, Osaka, JP;
Panasonic Corporation, Kadoma-shi, JP;
Abstract
An optical pickup device is provided which is compatible with at least two types of optical disc standards having different NAs and which controls an effective NA when a light beam for an optical disc standard having a relatively small NA is converged, thereby forming a desired spot. An inner partB and an outer partF of an objective lens elementare provided with diffraction structures different from each other. A condition (1), DO×DO>0, and a condition (2), DO×DO<0, are satisfied (DO(DO) is the diffraction order of the diffracted light beam having the highest diffraction efficiency among light beams of the wavelength λ(λ) diffracted by the diffraction structure on the inner part; and DO(DO) is the diffraction order of the diffracted light beam having the highest diffraction efficiency among light beams of the wavelength λ(λ) diffracted by the diffraction structure on the outer part).