A Large Area, High-speed CCD Imager Suitable for Use in Ambient Lighting Conditions

High-speed, large area detector arays are needed for recording fast events in both military and commercial applications. Deblurring of high-velocity targets within an image require extremely short exposure times. Short exposure times in turn, reduce the time availble for photon intergration and, because of increased amplifier bandwidths, result in higher noise levels at the CCD sense node. The desire to take high quality (high-speed) images under ambient lighting conditions imposes a need to optimize both the light gathering capability of the individual photosites and the sensitivity of the CCD output amplifier. Previous efforts at reducing sense node capacitance have been hampered by either physical constraints of the fabrication process, or band-width limitations imposed by using lightly oped drain techniques. Deblurring of high-speed events typically equires interline transfer CCD designs which allow for high-speed shuttering capability, but severely limit the detector element's light gathering capability. SMD proposes an alternative imaging architecture which optimizes both photosite and amplifier sensitivity through the use of novel micromachining techniques. The modified amplifier and photosite structure promises to achieve charge to voltage conversion gains of l00 to 200 microvolts per electron.