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:
Mar. 08, 1994
Filed:
Jun. 04, 1991
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A focus state detection device comprising: a first optical conversional system for forming an optical flux in one of two symmetric regions with respect to an optical axis of an optical flux from a subject to be photographed; a second optical conversional system for forming an optical flux in the other of the two symmetric regions; and a third optical conversional system for forming an optical flux in a region including the optical axis. The device further comprises a first and a second photoelectric converters for generating electric signals in response to optical intensity distribution data of the fluxes formed by the first and second systems, respedtively; a third photoelectric converter for generating an electric signal in response to optical intensity distribution data of the flux formed by the third system; and a calculation unit for detecting a focus state of the subject on the basis of correlation between three electric signals output from the first, second and third converter means.