JP2636898B

PURPOSE:To prevent overflow even at the time of excessive incident light entrance so as to obtain normal operation under various kinds of conditions by forming an overflow gate and an overflow drain adjacently to an input source, and driving these at specific voltage. CONSTITUTION:Voltage VL lower than voltage VH is applied to an overflow gate 30. The voltage of an input gate 11 is VIG, and the voltage of a transfer gate 13 is 0V. Though a barrier 32 is made higher by the voltage VL, it is far lower than threshold voltage VT, and the charge from a photoelectric transfer element 4 is shut off at the barrier 32 and is accumulated in the potential well 34 of an accumulating gate 12 over a barrier 33 right below the input gate 11. When extremely great excessive incident light enters in the condition that a barrier 35 right below the gate 13 is high with the voltage of the gate 13, 0V, the charge of the well 34 overflows, but as the barrier 32 is slightly lowered in advance by the voltage VL this overflowed charge goes over the barrier 32 and is absorbed in an overflow drain 31 and never flows out to a read-out line.