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:
Sep. 10, 2013
Filed:
Mar. 05, 2012
Katsuhiko Hayashi, Nara, JP;
Yasuhiro Tanaka, Hyogo, JP;
Michihiro Yamagata, Osaka, JP;
Fumitomo Yamasaki, Nara, JP;
Katsuhiko Hayashi, Nara, JP;
Yasuhiro Tanaka, Hyogo, JP;
Michihiro Yamagata, Osaka, JP;
Fumitomo Yamasaki, Nara, JP;
Panasonic Corporation, Kadoma-shi, JP;
Abstract
An optical system for optical pickup includes a magnification conversion optical element moving along an optical axis direction in accordance with each of optical recording medium recording surfaces, and an objective lens element converging a light beam incident through the magnification conversion optical element, to form a spot on a corresponding one of the recording surfaces, and satisfies the following formula: 4.0×10<Mn/(tn−tc)×f<6.0×10. Here tc is the thickness [μm] of a recording-medium base material at which a third-order spherical aberration occurring when a parallel light beam is incident on the objective lens element is the minimum, f is the focal length [mm] of the objective lens element, and Mn is the imaging magnification of the objective lens element when a spot is formed through a thickness tn [μm]of the base plate.