Patent ID: 6489615
Filing Date: 2002-12-03
Classification: G01J

Abstract:
An electromagnetic radiation sensor assembly, comprising:means for providing a heat bath; a thermally responsive absorber element for detecting radiant electromagnetic energy; an intermediate stage for thermally isolating the absorber element from the means for providing a heat bath, and including first and second thermal isolation member, 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 member being located between the absorber element and the intermediate stage and the second thermal isolation member being located between the intermediate stage and the means for providing a heat bath; an electro-thermal feedback circuit incorporated into the intermediate stage for reducing the thermal conductivity between the absorber element and the means providing a heat bath by causing the temperature of the intermediate stage to converge to the temperature of the absorber element when detecting radiation, effectively causing the thermal conductance of the first thermal isolation member 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 integrated with the intermediate stage and means for detecting the temperature difference between the absorber element and the intermediate stage and generating a temperature difference signal for controlling the amplifier and the heat generated thereby, and wherein the heat generated by 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.