Uncooled microbolometer trade off or new figure of merit for uncooled imager - art. no. 654224

NETD is not the sole parameter to characterize microbolometer array and other parameters are as important as this one, indeed when a products comparison is done, NETD values but not, systematically, technology data (such as thermal time constant...) and typical imager parameters can be used. However, as NETD is strongly dependant on the thermal time constant, it's important to compare microbolometer in the same conditions to evaluate advantages and drawbacks. This paper deals with the important parameters to compare microbolometer devices and propose a figure of merit to take into account thermal sensitivity as well as imager characterization: such as MTF, fill factor and thermal time constant, which are often forgotten in the data products; for example, a die with a NETD around 10mK and thermal time constant around 40ms will not be compliant with a 100 Hz frame rate and has to be compared with a 40mK, tau=10ms component. The important point is to compare the right criteria and to make the best choice for the application. An example will be also presented to see how to choose an uncooled array for a given application.