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. 30, 1990
Filed:
Mar. 21, 1989
Martin E Cooke, Salisbury, GB;
Andrew A Turnbull, Reigate, GB;
U.S. Philips Corp., New York, NY (US);
Abstract
Thermal radiation detection apparatus is provided comprising an array of pyroelectric detectors 1,2,3,4 in which compensation is provided for the effect of ambient temperature changes on the detector outputs and also for d.c. offsets which occur in source follower impedance converters 13 necessarily used with each detector. Single element detectors are used, the end pair of elements 3,4 being shielded from radiation and used as reference elements. Each element has a pair of diodes 11,12 connected in parallel in opposite sense to provide a d.c. path across the element. The reference element outputs are averaged 16,17,18 and fed via a high gain negative feedback loop 19 to the common connection 10 of all the elements. Offset voltages and element signals generated by ambient temperature changes are thereby compensated to the extent that the reference offsets and thermal voltages equal those of the active detector elements.