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. 09, 2008
Filed:
Mar. 14, 2007
Mitsuru Mimori, Kokubunji, JP;
Kohei Ota, Hachioji, JP;
Shinichiro Saito, Hachioji, JP;
Yuichi Atarashi, Hachioji, JP;
Katsuya Sakamoto, Hachioji, JP;
Hidekazu Totsuka, Hachioji, JP;
Kiyono Ikenaka, Hino, JP;
Mitsuru Mimori, Kokubunji, JP;
Kohei Ota, Hachioji, JP;
Shinichiro Saito, Hachioji, JP;
Yuichi Atarashi, Hachioji, JP;
Katsuya Sakamoto, Hachioji, JP;
Hidekazu Totsuka, Hachioji, JP;
Kiyono Ikenaka, Hino, JP;
Konica Minolta Holdings, Inc., Tokyo, JP;
Abstract
An objective optical element of an optical pickup apparatus has a magnification m1 satisfying the following formula for a light flux of the wavelength λ:−1/7≦m≦−1/25 and |m|<|Mwhere Mis an optical system magnification from the first light source to the first optical information recording medium for a light flux of the wavelength λ. The objective optical element comprises a common region and an exclusive region. The exclusive region includes an exclusive diffractive structure having a function to suppress an increase of spherical aberration due to a raise of atmospheric temperature. A light flux of a wavelength λ. having passed through the exclusive diffractive structure intersects with the optical axis at a position different from the position of the converged light spot formed on the information recording plane of the second optical information recording medium.