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:
Jan. 05, 1982
Filed:
May. 07, 1980
Minolta Camera Kabushiki Kaisha, Osaka, JP;
Abstract
A pentagonal prism for use in a viewfinder of a single lens reflex camera is made of a glass whose refractive index and Abbe number are not less than 1.6 and 45, respectively. Effective optical path regions on a pair of roof surfaces of the prism are left transparent so that viewfinder light can be totally reflected at both of the roof surfaces. A light absorbing paint is coated in an upper front surface, a pair of said surfaces of the prism as well as at regions other than effective optical path region of the roof surfaces, a bottom light incident surface and a rear light exit surface of the prism. The light absorbing paint prevents the occurrence of ghost images in the view field of the viewfinder. New type glasses suited for the prism are proposed.