SOLID-STATE IMAGE PICKUP ELEMENT

PROBLEM TO BE SOLVED: To show high sensitivity with output having a steep gradient in low illuminance and to enlarge the dynamic range of a solid-state image pickup element with output having a smooth gradient in high illuminance by constituting a light receiving part with a second photodiode whose potential well is deeper and whose light receiving quantity per unit area is less than a first photodiode. SOLUTION: The light receiving part constituted by the second photodiode 24 whose potential well is deeper and whose light sensitivity is lower than the first photodiode 22, and a transmission part constituted by a first transmission gate 30a transmitting charges accumulated in the first photodiode 22 to a transmission element and a second transmission gate 30b transmitting the charges accumulated in the second photodiode 24 to the transmission element are provided. Since the light receiving quantity of the second photodiode 24 is less, the gradient of the output corresponding to the illuminance is decreased for the illuminance higher than the saturation value. Since, information that illuminance is more than saturation one can be displayed without exceeding the capacity of a transmission terminal, the dynamic range of the solid-state image pickup element can be enlarged.