Patent ID: 8520105

Claim:
A solid-state image pickup device comprising: a pixel unit in which a plurality of photoelectric conversion elements having different sensitivities are arranged; and a pixel reading unit configured to read and add output signals from the plurality of photoelectric conversion elements in the pixel unit, and to obtain a sum signal as an output signal from one pixel, wherein, the pixel unit includes a floating diffusion that is shared by the plurality of photoelectric conversion elements, the plurality of photoelectric conversion elements include a first photoelectric conversion element having a first sensitivity, a second photoelectric conversion element having a second sensitivity, a third photoelectric conversion element having a third sensitivity, and a fourth photoelectric conversion element having a fourth sensitivity, the first, second, third, and fourth sensitivities are changed in accordance with an exposure time and satisfy a relationship of the first sensitivity being higher than the second sensitivity, the second sensitivity being higher than the third sensitivity, and the third sensitivity being higher than the fourth sensitivity, the first, second, third, and fourth photoelectric conversion elements are arranged such that the first photoelectric conversion element having the first sensitivity that is highest among the sensitivities is adjacent along horizontal and vertical directions to the fourth photoelectric conversion element having the fourth sensitivity that is lowest among the sensitivities and the third photoelectric conversion element having the third sensitivity that is lower than the second sensitivity, and the pixel unit includes a plurality of transfer transistors, each transfer transistor being associated with a corresponding one of the first, second, third, and fourth photoelectric conversion elements and configured (i) to transfer electric charge from the corresponding photoelectric conversion element to the floating diffusion and (ii) to selectively provide an overflow path configured to discharge overflowing electric charge from the photoelectric conversion element.