PURPOSE: To prevent a flicker phenomenon by providing a buffer circuit which makes a vertical scanning line selecting a photodiode being not inserted between plural vertical scanning lines to be selected non-selective faster than those being inserted in a solid-state image pickup element of a two-line simultaneous reading system.
CONSTITUTION: A gate line is turned off previously, which has a coupling capacity only with a single vertical gate line out of two selected vertical gate lines, and a gate line is turned off later, which has a coupling capacity with the two vertical gate lines. For example, after B and C are selected and turned on, and when B is turned off previously and then C off; when B is turned off, a transistor 44 is still under a conducting condition. Therefore, an electric potential Vsc of a photodiode 43 is free from the influence and when a vertical gate line 31 is turned off, the potential only drops due to a coupling capacity Cpc1. Therefore, the Vsc potential fluctuation is equal when a field changes, and C and C are simultaneously selected to be turned off, thereby eliminating the difference in the field fluctuation amount, and causing no flicker.
ANDOU HARUHISA
OOBA SHINYA
TAKEMOTO KAYAO
