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:
Apr. 19, 2011
Filed:
Jul. 23, 2009
Naoki Yamagata, Tokyo, JP;
Shuichi Takeuchi, Saitama, JP;
Naoki Yamagata, Tokyo, JP;
Shuichi Takeuchi, Saitama, JP;
Hoya Corporation, Tokyo, JP;
Abstract
An objective lens used for an optical information recording/reproducing apparatus for an optical disc based on a predetermined standard is made of resin and has a numerical aperture larger than or equal to 0.75. When f (unit: mm) represents a focal length at a wavelength λ (unit: nm), d (unit: mm) represents a thickness, and n represents a refractive index of the objective lens at the wavelength λ, the objective lens satisfies following conditions:1.00<f<1.50  (1)1.55<<1.82  (2).At least a light source side surface of the objective lens is an aspherical surface. The objective lens satisfies a following condition:2.80<(SAG1)'  (3),