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:
Jul. 30, 1985
Filed:
Jun. 14, 1983
Kenichi Oinoue, Tokyo, JP;
Abstract
A method for detecting optically an F-number of an interchangeable imaging lens is disclosed. An image of an exit pupil of the imaging lens is projected onto an array of photoelectrically converting light receiving elements so as to measure a diameter of the image of the exit pupil of the imaging lens formed on the light receiving element array. The diameter of the exit pupil image is measured by counting the number of the light receiving elements whose photoelectrically converted outputs are larger than a predetermined threshold value and then the effective F-number of the imaging lens is detected in accordance with said counted number. Further, an image lateral shift amount detected by an image lateral shift detection system is corrected by the detected F-number and an accurate focus detection of the imaging lens can be performed.