Utlaesningselektronik foer Termiska IR-Detektorer av Bolometertyp (Read Out Electronics for Thermal Detectors of Bolometer Type).

摘要

Thermal infrared (IR) detectors can be used for imaging IR systems with high temperature resolution. One detector type which has shown high responsivity is the resistance bolometer. Radiometric calculations on the expected signal power for an IR camera with NETD = 0.1K has been made. Traditional readout technique for photon detectors is not directly applicable to bolometer detectors. During the read out of the signals from a bolometer one has to consider the power dissipation due to bias current through the detector. Further on, the choice of bias resistor is important for stability reasons because it is possible to overheat the detector when using unsuitable resistance values. Elementary theory for bolometers is mentioned and an example is given with values published by the Honeywell Company. There is a demand for low noise in the read out electronics. Noise calculations have been made for transistors with varying dimensions less than 50 micrometers x 50 micrometers in a typical CMOS-process. The results show that the 1/f-noise is dominating at low frequencies. Noise calculations for BiC-MOS have not been made, however, due to the lack of process parameters. One conclusion when comparing the two techniques is that one has to compensate for the 1/f-noise when using CMOS in the actual application.