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:
Oct. 01, 1985
Filed:
Sep. 07, 1984
Kikuo Momiyama, Kanagawa, JP;
Kazuo Fujibayashi, Kanagawa, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
In the single lens reflex camera including a photographic system having an objective lens and an image detector, and a viewfinder optically disposed of the photographic system and comprising a focusing screen having a transparent area surrounded by a light diffusing area, a prism for changing the direction of an optical path, and an eye-piece in sequence from the object, a light receiving element for light measuring is positioned away from an optical axis of the viewfinder in rear of an image forming lens for converging the light from the focusing screen to the light receiving element, and is provided with a mask for blocking the main part of an image of the transparent area which is formed by the image forming lens, thereby the proportionality between the variation of F-number of the objective lens and the amount of light measured is improved.