Bae Systems Information and Electronic Systems Integration Inc.

Paul R Murphy

Steven R Jost

A high resolution room temperature infrared camera requires no cryogenic cooling and high vacuum packaging, normally though necessary for infrared target detection, by using a &ldquo;blind&rdquo; polycrystalline lead salt resistor in combination with a matched active polycrystalline lead salt photoresistor both maintained at room temperature to provide a differential output indicative of an IR generating target. As a result of the matched components, the differential output nulls out the dark current which is the result of the ambient at the camera. The high degree of linearity associated with polycrystalline photoresistors permits fabrication of a differential detector where dark current in the active element is nulled out by equal and opposite current flow in a non-optically active reference resistor. Rather than a reference provided by a mechanical chopper normally used to correct for array non-uniformity, and rather than using costly temperature stabilization, the subject polycrystalline photoresistor provides a factory-setable reference, such that dark current can be canceled with the use of a nearly identical &ldquo;blind&rdquo; element beside the optically active element.

Growing community of inventors

Medford, MA, United States of America

Paul R Murphy