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:
Feb. 26, 1991

Filed:

Sep. 22, 1988
Applicant:
Inventors:

Hirokazu Tanaka, Tokyo, JP;

Kiyomitsu Ishikawa, Tokyo, JP;

Tohru Tanabe, Tokyo, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01V / ;
U.S. Cl.
CPC ...
250221 ; 250561 ;
Abstract

Here is disclosed a photoelectric detector comprising first and second light sources respectively having different light emitting areas, a photoelectric transducer member adapted to receive the light emitted from these light sources and then reflected on an object to be detected, and a signal processing circuit functioning to separate electric signals corresponding to the first and second light sources from an output of the photoelectric transducer member and to compare these separated two electric signals to each other so that presence or absence and a position of the object are detected on the basis of such comparison of the two electric signals.


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