A 310 K pixel bipolar imager (BASIS)

The BASIS (base-stored image sensor) bipolar imaging device, which consists of a bipolar phototransistor in a capacitor-loaded emitter-follower circuit, is discussed. The device is used in an imager with 310 K pixels (640 H*490 V) in a 2/3-in optical format. The imager exhibits excellent performance characteristics, such as a high aperture ratio of 60%, an image lag less than 0.1%, and good linearity with a dynamic range of 76 dB. The read out and reset operation, antiblooming capability, and total system circuit and FPN cancellation are discussed. >