A 250 k-pixel SIT image sensor operating in its high-sensitivity mode

A solid-state imaging device which uses a static induction transistor (SIT) is examined. The image sensor consists of 530(H)×490(V) pixels and is suitable for a 2/3-in optical format. An analysis of its operation predicts that the performance of the image sensor can be examined in detail using an equivalent circuit. A noise equivalent irradiance of 1.5×10^-4 μW/cm², when using light-emitting diodes (λ=660 nm) as a light source, was obtained in a frame integration mode. This is comparable to that of a high-sensitivity silicon intensifier target tube, although a large image lag of 80% during the third frame is also present. High sensitivity, is achieved because the gate reset levels of the SIT depend on the exposure and the change of the gate reset levels added to the output signal. It is predicted that the image sensor will be highly sensitive but that it will have a large image lag