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:
Jul. 20, 2010
Filed:
Mar. 18, 2008
Takaaki Yano, Hokkaido, JP;
Takaaki Yano, Hokkaido, JP;
Hoya Corporation, Tokyo, JP;
Abstract
A relay finder optical system, of a single-lens reflex camera, includes a condenser lens group, a prism, and a relay lens group, in this order from a primary imaging plane. An image, which is formed on the primary imaging plane, and is upside down and inverted from left to right, is re-formed on a secondary imaging plane for viewing by a photographer. The relay lens group includes a positive front lens group, a negative intermediate lens group, and a positive rear lens group, in this order from the object. The most photographers-eye side lens element of the positive rear lens group comprises a positive lens element having a convex surface facing toward the image, and satisfies the following conditions:1<SF  (1)−6<<−3  (2)SF: the shaping factor of the most photographers-eye side positive lens element (SF=(rr)/(rr)); r: the radius of curvature of the object-side surface of the most photographers-eye side positive lens element; r: the radius of curvature of the photographers eye-side surface of the most photographers-eye side positive lens element; f: the focal length of the relay finder optical system; and fM: the focallength of the negative intermediate lens group.