Microbolometer focal plane array with controlled bias

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 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 midpoint of 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 a function of any difference between said bias temperature reference reading value at said calibration instant of time and said bias temperature reference reading value corresponding to a last occurring one of said selected instants of time.