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. 25, 1994
Filed:
May. 28, 1991
Takashi Miida, Kanagawa, JP;
Hiroshi Iwabuchi, Kanagawa, JP;
Yoshimitsu Kudoh, Kanagawa, JP;
Hideki Mutoh, Kanagawa, JP;
Fuji Photo Film Co., Ltd., Kanagawa, JP;
Abstract
A phase difference detection unit for an automatic focusing system of a camera or the like. The phase difference detecting unit includes a pair of linear image pickup devices which receive a pair of optical images of an object formed by the lens in the automatic focusing system of a camera or the like. The detecting unit also has a correlation operating circuit which determines whether or not the lens of the focusing system is in a proper focus condition. The proper focus condition is determined by a minimum correlation value output by the correlation operating circuit, the value being indicative of the correlation between a pair of phase shifted analog electrical signals representative of the optical images received by the pickup devices. The correlation operating circuit is capable of operation at high speed with improved accuracy by maintaining the capacitive loads of the input terminals of the correlation operating circuit.