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.

Date of Patent:
May. 09, 1989

Filed:

Nov. 12, 1987
Applicant:
Inventors:

Tokuji Ishida, Osaka, JP;

Katsumi Kozakai, Sakai, JP;

Masataka Hamada, Osaka, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G02B / ;
U.S. Cl.
CPC ...
250201 ; 250204 ; 354408 ;
Abstract

In a focus detection system for detecting the focus condition of an objective lens, there is disposed a pair of photosensor arrays for generating a plurality of image signals. The peak signal of the plurality of image signals is detected and compared with a predetermined constant level. The amount of defocus of the objective lens is calculated in accordance with the plurality of image signals when the detected peak signal is over the predetermined constant level. It is determined that focus detection is impossible when the detected peak signal is below the predetermined constant level.


Find Patent Forward Citations

Ishida, Tokuji. (1989). Digital focus detecting device (U.S. Patent No. 4829170). U.S. Patent and Trademark Office. https://idiyas.com/patent/badge/4829170

Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile

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