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:
Apr. 03, 1990
Filed:
Jan. 09, 1989
Akira Akashi, Yokohama, JP;
Akira Ishizaki, Yokohama, JP;
Akira Hiramatsu, Yokohama, JP;
Yasuo Suda, Yokohama, JP;
Keiji Ohtaka, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A focus detection system for detecting a focus state of an object lens, includes an optical device for forming first and second light distributions corresponding to first and second images having light fluxes passing through the different parts of a pupila of the object lens. The positional relationship between the two light distributions varies in accordance with the focus state of the object lens. First and second sensors sense the first and second light distributions. A signal processor for processing output signals from the first and second sensors detect the focus state of the object lens in accordance with the positional relationships between the two light distributions. The signal processor processes the signals from the first and second sensors in accordance with a predetermined formula to obtain the positional relationship between the two images to determine a degree of coincidence of the two light distributions. The signal processing means provides an output signal in accordance with the degree of coincidence of the two light distributions.