Abstract: A high-resolution radiation detector cell array has a planar substrate, with multiple switching circuits, interposed between a detector substrate and a subsequent substrate containing high-sensitivity preamplifiers; each of the middle-substrate switching circuits operates to substantially continuously connect cyclic different ones of an assigned different set of the array cells to an associated single one of multiple preamplifiers. In a N.times.M array of cells used with a C column-by-R row switching subassembly, a total array of (N/C).times.(M/R) preamplifiers are needed. The generally-planar detector, switch and preamplifier substrates can be connected using metallic "bump" contacts; the switch layer material may be selected to have a CTE between the CTEs of the detector and preamplifier layers.

Abstract: The invention relates to charge injection devices (CID) for sensing IR image intensity information obtained from a two dimensional array of dual-gate sensing sites on an InSb or HgCdTe substrate, and more particularly to a novel push-pull readout circuit which eliminates the pedestal due to capacitive coupling between gates on the same pixel of a dual gate CID. The CID is scanned in rows and read out in parallel columns. Pedestal cancellation is achieved in one example by resetting the prior row as a selected row is injected. In a second example pedestal cancellation is achieved by adding an additional row which is reset as each row is injected, while in a third example a pedestal cancellation network is provided associated with each column output circuit.

Abstract: The invention relates to a read and clear readout circuit and a method of operation of an IR sensing array. The invention eliminates "readout circuit lag" which reduces transient response for an individual sensor, and reduces angular resolution of an array. "Readout circuit lag" also emphasizes longer duration IR background causing unwanted saturation and restriction of the dynamic range. Readout circuit lag arises from the capacitance of the sensor elements and the capacitance of the readout circuit at a node to which the sensor elements are periodically coupled for readout, the IR induced charge being partitioned between these capacitances, with that attributable to the sensor capacitance not being injected, causing readout circuit lag. Elimination of such lag is achieved by following each readout step, with a clear or clear and skim step that removes charge to the clear level or to the skim level, precluding the lag earlier described.

Abstract: The invention relates to an improved readout circuit and readout method for an IR sensing array. The invention, given a limited time interval for reading out the signal from a sensor element in an array of sensor elements, permits a longer time to be devoted to the injection of charges into the substrate, thereby reducing device "lag" (the retention of uninjected charges). The readout is carried out by a two step, direct coupled, injection process. The first step involves independent, but simultaneous resetting of the sensor elements and the preamplifier input (at a node having sufficient capacity to supply the charges required for injection). The voltages are suitable for IR induced charge storage in the sensor elements, and for subsequent injection by the nodal capacity. A first sample is taken by a correlated double sampling circuit from the preamplifier output during the first step as the resetting stabilizes.

Abstract: Apparatus is provided for periodically reading image intensity information from M rows x N columns of charge storage sites in a CID array imager. The magnitudes of signal charges collected at the sites in response to incident radiation are sensed by measuring changes in potential on column lines connected to the respective columns of sites. These changes in potential are caused by sequentially applying specific potentials to row lines connected to the respective rows of sites to effect injection of the signal charges into the substrate of the array. The apparatus operates to minimize charge transfers within the array during readout and is thus capable of accurately determining the magnitude of signal charges in arrays fabricated from semiconductor materials having low charge transfer efficiencies. The apparatus includes means for eliminating the effects of thermal (KT/C) noise from output voltages representative of the signal charge magnitudes.