Patent ID: 6538250
Filing Date: 2003-03-25
Classification: H01L,H04N

Abstract:
A method for controlling bias for an microbolometer focal plane array associated with a substrate, and which said microbolometer focal plane array includes a plurality of substrate-isolated microbolometer detectors and one thermally-shorted microbolometer detector thermally shorted to said substrate, and wherein associated with said microbolometer focal plane array is a circuit means, including an electric signal bias source, for determining, for each of said microbolometer detectors, a reading value representative of the corresponding temperature associated therewith, the method comprising the steps of:setting the magnitude said electric signal bias source to a bias source calibration magnitude such that an average value representative of the average of each reading value associated with all of said substrate-isolated microbolometer detectors at a calibration instant of time is substantially at a selected value within a selected reading value range at a calibration instant of time; determining a bias temperature reference reading value representative of the temperature of said thermally-shorted microbolometer detector at substantially said calibration instant of time; determining a bias temperature reference reading value representative of the temperature of said thermally-shorted microbolometer detector at selected instants of time subsequent to said calibration instant of time; adjusting said bias electric signal source to an operating magnitude value, where said operating magnitude value is substantially equal to the sum of: (i) said bias source calibration magnitude, and (ii) a selected scale factor multiplied by the difference between a. said bias temperature reference reading value at said calibration instant of time, and b. said bias temperature reference reading value corresponding to a last occurring one of said selected instants of time.