| 摘要 |
PURPOSE:To equalize a supplied source voltage to a buffer amplifier circuit with a bias voltage impressed between the electrodes of a photoelectric converting element by reducing a signal level inputted to the buffer amplifier circuit. CONSTITUTION:The circuit is equipped with a bias switching element 5 to connect and arrange serially a capacitive element 4 between a signal removing electrode 1a of a photoelectric converting element 1 and the input edge of a buffer amplifier circuit 3 and switch a bias Vo impression or interruption to the input terminal of the buffer amplifier circuit 3 and a switching control means 6 to switch a reference bias switching element 2 from a bias Vo impressing condition to the interrupting condition in the bias impressing condition by the bias switching element 5 and thereafter, switch the bias switching element 5 to the bias interrupting condition and the reference bias switching element 2 to the bias impressing condition. Consequently, the signal level inputted to the buffer amplifier circuit 3 is the one lower than a reference bias voltage Vb to the photoelectric converting element 1.
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