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:
Oct. 06, 1998
Filed:
Jan. 13, 1997
Fernando Erismann, Elk Grove, CA (US);
C & K Systems, Inc., Folsom, CA (US);
Abstract
A passive infrared intrusion detection device uses a dual element pyroelectric detector and a housing for surrounding and containing the dual element pyroelectric detector. The housing has a plurality of Fresnel lens elements for gathering infrared radiation from a 'look down' volume of space and for focusing the gathered infrared radiation onto the pyroelectric detector. A mask positioned between the plurality of Fresnel lens elements and the detector partially occludes the gathered infrared radiation from the Fresnel lens elements to one of the elements of the dual element pyroelectric detector creating an imbalance in the signal thereby preventing common mode rejection.