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:
Dec. 01, 1987
Filed:
Dec. 26, 1985
Applicant:
Inventors:
Kurt Muller, Stafa, CH;
Walter Meier, Mannedorf, CH;
Assignee:
Cerberus AG, Mannedorf, CH;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01J / ;
U.S. Cl.
CPC ...
250342 ; 2502521 ; 250349 ; 250353 ;
Abstract
In an infrared intrusion detector which evaluates the body radiation of an intruder by means of a dual radiation sensor having two sensor elements arranged in a differential circuit for emitting an alarm signal, a functional supervision and detection of an attempt at sabotage, e.g., by covering or spraying the entrance window, are achieved by asymmetric irradiation of the two sensor elements through the entrance window by a radiation source. The asymmetry can be achieved by disposing the radiation source outside the plane of symmetry of the sensor elements or by an asymmetrically disposed auxiliary reflector.