IMAGE SENSOR

PURPOSE:To obtain an image sensor with high density and high speed in which noise is reduced by integrating a photo sensor, a reset switch, an impedance conversion circuit, a readout switch and a signal scanning circuit on one and same substrate. CONSTITUTION:Many photo diodes 1 arranged linearly, a reset switch 3, an impedance conversion circuit comprising 1st and 2nd transistors (TRs) 5, 6, a readout switch 10, a shift register 12, and a signal scanning circuit consisting of a level shifter 13 and a multiplexer 14 are provided to the image sensor. The photo diodes 1 are made of amorphous silicon, other circuit part consists of a thin film TR made of a polycrystal silicon, and they all are integrated on one and same substrate. Thus, A signal having a voltage linear to an input voltage is outputted and the variance of the characteristic among components is auto-corrected. Moreover, the parasitic capacitance in the cross region between output wires is reduced to reduce noise and high speed operation with high density is attained.