CRYOGENIC INFRARED SOURCE ARRAY

IN ORDER TO ADEQUATELY TEST AND SIMULATE IMAGES FROM LONG WAVE INFRARE D (LWIR) SENSORS, COMPLEX DYNAMIC TARGET AND BACKGROUND SCENES MUST BE GENERATED. METHODS FOR GENERATING SUCH SCENES IN INFRARED (IR) ARE COSTLY, TIME CONSUMING, AND INADEQUATE. TO REDUCE THESE DRAWBACKS, IR SCENE GENERATING ARRAYS HAVE BEEN DEVELOPED FOR IN-THE-LOOP SIMULATIO N AND TESTING OF IR SYSTEMS. TYPICALLY THE IR SCENE GENERATING ARRAYS CONSIST OF AN ARRAY OF RESISTORS THAT ARE HEATED TO SPECIFIC TEMPERAT URES BY JOULE HEATING. SEVERAL COMPANIES HAVE DEVELOPED ARRAYS TO OPE RATE AS LOW AS LIQUID NITROGEN TEMPERATURE (77K); HOWEVER, TO REPRODUC E LOW BACKGROUND SCENES, THE IR SOURCE ARRAYS MUST OPERATE AT MUCH LOW ER TEMPERATURES--TO 20K. THIS PUTS AN ADDITIONAL BURDEN ON THE ARRAY SINCE THE CIRCUITRY MUST OPERATE COLD. PROPOSED IS A METHOD TO SOLVE THE PROBLEMS ASSOCIATED WITH A MONOLITHIC IR ARRAY. THE CONCEPT USES ELECTRON BEAMS GENERATED BY AN ARRAY OF VACUUM MICROELECTRONICS DEVICE S (VMDS) TO HEAT THE IR SOURCES. THIS ALLOWS THE SILICON CIRCUITRY TO OPERATE AT HIGHER TEMPERATURE BECAUSE THE IR SOURCE AND THE VMD DRIVE CIRCUITRY ARE NOT PHYSICALLY CONNECTED. ALSO, NEARLY 100% FILL FACTO R CAN BE ACHIEVED. THIS METHOD HAS POTENTIAL TO PRODUCE VERY HIGH SPE ED AND HIGH RESOLUTION ARRAYS.