| 摘要 |
PURPOSE:To reduce noises generated in an element, and to improve the sensitivity of the whole device by providing a phototransistor having amplifying functions at every picture element and a switching means. CONSTITUTION:An n type Si substrate 31, a p type impurity diffusion layer 32 and an n type impurity diffusion layer 33 constitute a phototransistor (a photo- Tr), and each function as a collector, a base and an emitter. The n type impurity diffusion layer 33 is brought into ohmic-contact with an n type impurity diffusion layer 35 formed in a p type impurity diffusion layer 34. n type impurity diffusion layers 35, 37 and poly Si 38 each represent a drain, a source and a gate in an MOSTr. When beams are projected to the base 32, the potential of the base 32, the source 33, is changed in the forward direction. That is, a reverse bias is applied between the source 35 and the well 34. Consequently, electrons are not injected from the source 35 even when intense beams are projected, and no blooming is generated. Electrons generated in the substrate 31 cannot intrude into the well 34, and no blooming is generated. |
