Frishauf, Holtz, Goodman, Langer & Chick
Photoelectric conversion system
 A photosensor formed on an insulating substrate has a transparent top gate electrode arranged on the upper side of a semiconductor layer for photoelectric conversion and a bottom gate electrode arranged on the lower side of the semiconductor layer. If light is applied from the top gate electrode side in a state in which a bottom gate voltage V.sub.BG =+20 V is applied to the bottom gate electrode and a top gate voltage V.sub.TG =-20 V is applied to the top gate electrode, electron-hole pairs are generated in the semiconductor layer and only the holes are held in the semiconductor layer by the effect of the top gate voltage V.sub.TG =-20 V. Therefore, an n-channel is formed in the semiconductor layer and a drain current I.sub.DS flows. It was confirmed that the drain current I.sub.DS will not flow even if illumination light is applied when the bottom gate voltage V.sub.BG is set at 0 V. Therefore, the selection or non-selection state of the photosensor can be controlled by the bottom gate voltage V.sub.TG. 
Casio Computer Co., Ltd.
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inventional inventional additional inventional inventional
Hiroyasu
Yamada