| 摘要 |
PURPOSE:To detect a readout signal in a state that a spike noise component due to the thin film transistors for signal readout switching and the noise components of photodetectors themselves are removed by making a differential amplification the signals to be outputted from the thin film transistors for signal readout switching and the thin film transistors for dummy signal detection. CONSTITUTION:With photodetector arrays 11 for signal detection formed on a substrate, dummy photodetector 18 having the same electrical characteristics as those of the photodetector arrays 11 are formed on the same substrate. Moreover, with thin film transistors 23 for signal readout switching formed on the above substrate to the light- receiving element arrays 11, thin film transistors 25 for dummy signal detection; which have the same electrical characteristics as those of these thin film transistors 23 for signal readout switching, are switched at the same timing as that of the thin film transistors 23 and also, are commonly connected to the above dummy photodetectors 18; are formed on the same substrate. Furthermore, a differential amplifier 27 to make a differential amplification the signals to be outputted from these thin film transistors 23 for signal readout switching and these thin film transistors 25 for dummy signal detection is provided.
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