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:
May. 29, 2012
Filed:
Nov. 18, 2010
Daisuke Koreeda, Saitama, JP;
Shuichi Takeuchi, Saitama, JP;
Daisuke Koreeda, Saitama, JP;
Shuichi Takeuchi, Saitama, JP;
Hoya Corporation, Tokyo, JP;
Abstract
An objective optical system for an optical information recording/reproducing apparatus for recording/reproducing for first, second and third optical discs by selectively using three types of substantially collimated light beams including first, second and third light beams respectively having first, second and third wavelengths, wherein at least one of optical surfaces of the objective optical system comprises a diffraction surface having a diffraction structure, the diffraction surface includes a first region defined by first and second optical path difference functions, a second region defined by at least one type of optical path difference function, and a third region defined by at least one type of optical path difference function, the first region satisfies a condition:−0.15<1/<−0.03  (1),