Patent ID: 7064328
Filing Date: 2006-06-20
Classification: G01J

Abstract:
1. An electromagnetic radiation sensor assembly, comprising: a heat bath; an antenna element for receiving radiant electromagnetic energy; a thermally responsive absorber element coupled to the antenna element and including means for absorbing and detecting radiant electromagnetic energy received by said antenna element; an intermediate stage for thermally isolating the absorber element from the heat bath, said intermediate stage including at least two first and at least two second thermal isolation members each having a predetermined thermal conductance interconnecting the absorber element to the intermediate stage and the intermediate stage to the heat bath, the first thermal isolation members being located between the absorber element and the intermediate stage and the second thermal isolation members being located between the intermediate stage and the heat bath; an electro-thermal feedback circuit incorporated into the intermediate stage for reducing the thermal conductivity between the absorber element and the heat bath by causing the temperature of the intermediate stage to converge to the temperature of the absorber element when detecting electromagnetic radiation, thus effectively causing the thermal conductance of the first thermal isolation members to attain a minimum conductance value and thereby improve the sensitivity of the radiation sensor towards the radiation limit; and wherein the electro-thermal feedback circuit includes a heat generating amplifier including a bipolar transistor integrated with the intermediate stage and means for detecting the temperature difference between the absorber element and the intermediate stage and generating an output voltage signal dependent on the received electromagnetic radiation to control the power generated by the amplifier, wherein the heat generated by the transistor included in the amplifier itself directly heats the intermediate stage in response to said temperature difference signal so as to equalize the temperature between the absorber element and the intermediate stage.