Active matrix of amorphous silicon multijunction color sensors for document imaging

An integrated color image sensor, made entirely with amorphous silicon (a-S i:H) large-area technology, is presented. The a-Si:H based sensor is a doub le-junction p-i-n-i-p photodiode that discriminates two spectral bands acco rding to the bias voltage. The active-matrix addressed array has 512x512 pi xels with 75 mum pixel pitch and uses thin-film transistors as pixel switch es. The array structure and the spectral response are discussed, and color images taken by the system using two bias voltages demonstrate the compatib ility of color sensors with large-area active-matrix addressing techniques. (C) 2001 American Institute of Physics.