Study On Readout Architectures For Uncooled Vanadium Oxide Infrared Radiation Detector Arrays

The uncooled microbolometer detector technology has increased the interest in infrared sensors since the requirements of compact, low-cost and reliable sensors can be met using this technology. Focusing on readout architectures for uncooled vanadium oxide infrared radiation detector arrays the electronic performace and principle of microbolometer are described. Using method of theoretical calculation and simulation analysis vanadium oxide non-linear thermal resistance' model is presented. Even though this model has some performance to be improved it can be combined well with readout circuit to analyse the whole performance of detector array. A noise model including Johnson noise, 1/f noise and thermal fluctuation noise is derived for the microbolometer detector and readout circuit. Pixelwise,columnwise and serial readout architecture are described and compared with respect to NETD while keeping the total power consumption of the microbolometer array constant. The obtained results emphasize the importance of low 1/f noise in the detector to reach low NETD. The estimated temperature change due to the self-heating of the microbolometer detector is low in comparison with the ambient temperature. That makes a small influence in the noise estimation. Studying the comparison results of the readout architectures the pixelwise readout architecture is found to be the preferable choice for the implementation.