A highly sensitive thermistor bolometer for a clinical tympanic thermometer

A newly designed infrared radiation sensor for a clinical tympanic thermometer has been developed. A very small packaging size (2.2 mm x 2.3 mm x 0.8 mm) is achieved so that the sensor can be used in the human auricle. To realize high sensitivity, infrared sensing regions in the shape of a pair of micro-air-bridges are encapsulated in a vacuum microchamber through a successive silicon batch process using micromachining techniques. The sensor shows a sensitivity R(v) of 5000 V W-1 and a noise equivalent temperature difference (NETD) of 0.062 degrees C at a d.c. bias voltage of 1.56 V.