Contactless phototransistor for bipolar sensor in imaging display

摘要

The phototransistor (40) includes a first conductivity collector region (44) formed in a second conductivity substrate. In the collector region a second conductivity base region (46) is formed. In the base region a first conductivity emitter region (48) is formed. A first conductivity shutter region (42) is formed in the base region, spatially separated from the emitter region, and electrically insulated. A shutter control line is formed over the shutter region and electrically coupled to it. Preferably the first conductivity is of n-type, while the second one is of p-type, or vice versa. The shutter region typically reacts to lower voltage than the emitter region. A matrix made of a number of phototransistors has row selection line and capacitor over emitter region, with capacitor coupling base region to row selection line.