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:
Feb. 25, 2014
Filed:
Feb. 17, 2011
Kazuki Matsui, Hachioji, JP;
Yasunari Fukuta, Osaka, JP;
Kazuki Matsui, Hachioji, JP;
Yasunari Fukuta, Osaka, JP;
Konica Minolta Advanced Layers, Inc., Tokyo, JP;
Abstract
Disclosed is an imaging lens by which astigmatism and field curvature are satisfactorily corrected by arranging on a first surface a concave surface having an appropriate radius of curvature. Condition (1) defines the radius of curvature of the concave surface arranged on the object-side surface of a bonded compound lens. By fulfilling condition (1), a lens can be obtained in which astigmatism and field curvature are satisfactorily corrected. Condition (1): −1.5<rL11/f<−5.0, wherein rL11 is the local curvature radius of the object-side surface of the first lens calculated by the equation below; f is the focus distance of the entire system. rL11={(h1)2+(s1)2}/(2s1); h1 is 1/10 of the effective radius of the object-side surface of the first lens; and s1 is the displacement amount in a direction parallel to the optical axis from the surface apex point at a lens surface height h1.