A new contact type image sensor chip has been developed, which integrates a phototransistor and a planar thyristor shift register using a simple bipolar IC process. The combination of the simple IC process and the shift register makes it possible to realize a high performance and low cost sensor chip. A B4 size contact type image sensor using the sensor chips and a reading unit have achieved excellent performance in which S/N ratio is over 40dB at a exposure of 0.05 lx.s.
