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. 04, 2012
Filed:
Apr. 15, 2008
Yukiko Hamano, Kanagawa, JP;
Hideaki Hirai, Kanagawa, JP;
Toshimichi Nasukawa, Iwate, JP;
Kazuhiro Umeki, Iwate, JP;
Yukiko Hamano, Kanagawa, JP;
Hideaki Hirai, Kanagawa, JP;
Toshimichi Nasukawa, Iwate, JP;
Kazuhiro Umeki, Iwate, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A disclosed optical pickup includes an aberration correction unit with a phase shifter surface. On the phase shifter surface, rectangular or staircase-like steps are formed in a concentric manner around an optical axial center, in certain regions where a light beam passes through. The steps have different heights in the optical axial direction. A light beam having a wavelength of 405 nm is directly transmitted through the steps so that a phase difference is applied for correcting spherical aberration that occurs on a first optical recording medium. A light beam that passes through an annular region without any steps is focused on a second optical recording medium. A light beam that passes through an outside region is focused by an object lens on the second optical recording medium, and is not focused on the first optical recording medium.