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:
Aug. 02, 2011
Filed:
Apr. 15, 2005
Hiroaki Yukawa, Kanagawa, JP;
Hiroaki Yukawa, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
The present invention provides an optical pickup in which the transmission diffraction efficiency of plural recording and/or reproducing light beams of different wavelengths, radiated from plural light sources, may be prevented from being lowered, and in which the transmission diffraction efficiency and the angle of diffraction are both optimized. The optical pickup includes an imaging unit composed of an objective lens and a set of diffraction section and adapted for condensing light beams from first to third light sources on optical recording mediums, and the set of diffraction section includes a first diffraction section which gives the transmission diffraction efficiency for order-one diffracted light or order-minus-one diffracted light higher than that for light of the other orders in case light beams of first, second and third wavelengths are transmitted therethrough, and a second diffraction section which gives the transmission diffraction efficiency for order-zero diffracted light higher than that for light of the other orders in case the light beam of the shortest wavelength and the light beam of the longest wavelength out of the first, second and third wavelengths are transmitted therethrough, and the transmission diffraction efficiency for order-one diffracted light or order-minus-one diffracted light higher than that for diffracted light of the other orders in case the remaining light beam is transmitted therethrough.