High Speed and High Resolution ISO A4 Size Amorphous Si:H Contact Linear Image Sensor

A contact linear image sensor has been developed as a new device to satisfy the requirement for facsimile equipment size reduction. An amorphous Si (a-Si:H) metal insulator semiconductor (MIS) photodiode, which has the excellent small dark current characteristics, is used as the photosensing element. In this sensor element the thermal stability of the electrode material was examined and optimum material was selected. For detecting signals stored in the photosensing elements, 64 bit/ chip integrated circuits (IC's) with a new driving method, which achieves the low noise and high speed operation, were designed and developed. These IC's are mounted on the sensor device substrate. International Standards Organization (ISO) A4 size 8 elements/mm and 12 elements/ mm sensor units in light-emitting diode (LED) light source have been developed. The sensor units characteristics in practical use give signal/ noise ratio (SNR) of 30 dB at 1.5-2.5 ms/line.