Technology for low cost PIR security sensors

Current passive infrared (PIR) security sensors employing pyroelectric detectors are simple, cheap and reliable, but have several deficiencies. These sensors, developed two decades ago, are essentially short-range moving-target hotspot detectors. They cannot detect slow temperature changes, and thus are unable to respond to radiation stimuli indicating potential danger such as overheating electrical appliances and developing fires. They have a poor optical resolution and limited ability to recognize detected targets. Modern uncooled thermal infrared technology has vastly superior performance but as yet is too costly to challenge the PIR security sensor market. In this paper microbolometer technology will be discussed which can provide enhanced performance at acceptable cost. In addition to security sensing the technology has numerous applications in the military, industrial and domestic markets where target range is short and low cost is paramount.