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:
Dec. 25, 1979
Filed:
Mar. 17, 1978
Applicant:
Inventors:
Masahiro Kawasaki, Tokyo, JP;
Yoshio Sawada, Tokyo, JP;
Assignee:
Asahi Kogaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
G03B / ;
U.S. Cl.
CPC ...
354 24 ; 354 51 ; 354 / ;
Abstract
A novel photometric circuit for a camera is disclosed wherein the operational amplifiers common to conventional photometric circuits are eliminated from that part of the circuit which solves the exposure Apex indication equation: S.sub.v +B.sub.v =A.sub.v +T.sub.v. The variable resistors which are used to convert the film sensitivity and aperature settings into electrical quantities are positioned in the feedback circuit of the transistor which is connected to the electro-optical transducer and which develops a voltage dependent upon scene brightness.