A new imaging device using amorphous silicon

A new imaging tube has been fabricated and successfully operated. In this tube, hydrogenated amorphous silicon (a-Si:H) is used as the photoconductive target. This target has a blocking type structure and is covered with a layer which has a high secondary electron emission yield, and its surface is scanned by a high velocity electron beam. The internal electric field in the photoconductor is the opposite of those used in conventional tubes, in that the secondary electron current, which is proportional to the light intensity, is obtained as a video signal. This new imaging tube overcomes a lot of disadvantages with conventional imagers in that it has high photosensitivity in the visible wavelength range, very small decay lag at high and low illumination levels, a high resolution of more than 700 TV lines uniformly, no burning and no blooming.