The successful demonstration of staring lead salt based focal plane technology has been impeded by one, the inability of previously existing ROIC technology to integrate the substantial dark currents associated with near room temperature operation of photoconductive detectors and two, the limitations of surface morphology of lead salt substrate materials. To address these technical challenges, we have developed an ROIC which operates very well with the high dark current of these devices and have developed a concept for detector pixel integration called balanced differential input (BDI). The BDI concept effectively nulls out a significant portion of the dark current before the ROIC input stage. With the development of the BDI device we have successfully addressed the issue of ROIC dynamic range. The BDI detector is comprised of two elements within a single unit cell. One cell is, in effect, "blind" and the other an active cell. the biasing scheme allows for equal and opposite dark currents. By combining the currents at the input circuit, the integrating capacitor will need to store the difference between the light and dark currents.
Benefits: Besides the advantage of significantly lowering the military system cost for MWIR sensors the commercial benefits are substantial. The concept should reduce, for example, the cost of a MWIR camera for firefighter protection by a factor of two to under $10K. The potential for spectroscopy and remote sensing applications are boundless.
Keywords: Infrared cameras, Remote sensing Infrared imaging
