A CMOS sensor has unit pixels each structured by a light receiving element
and three transistors, to prevent against the phenomenon of saturation
shading and the reduction of dynamic range. The transition time (fall
time), in switching off the voltage on a drain line shared in all pixels,
is given longer than the transition time in turning of any of the reset
line and the transfer line. For this reason, the transistor constituting
a DRN drive buffer is made proper in its W/L ratio.Meanwhile, a control
resistance or current source is inserted on a line to the GND, to make
proper the operation current during driving. This reduces saturation
shading amount. By making a reset transistor in a depression type, the
leak current to a floating diffusion is suppressed to broaden the dynamic
range.