A method of driving a solid-state image pickup apparatus suppresses a shading in the dark output of the apparatus. The apparatus has a line of photosensors to produce signal charges in response to the intensity of incident light, and parallel lines of analog shift registers to successively transfer the signal charges from the photosensors. When the charges are transferred from an inner one of the shift register lines to an outer one thereof, dark charges in the inner shift register line are kept as they are.

In a CCD type solid state image pickup device including two-dimensionally arranged photo/electro conversion portions, a plurality of vertical shift registers each connected to one column of the photo/electro conversion portions, and a horizontal transfer portion connected to the vertical shift register, signal charges of every four of each column of the photo/electro conversion portions are mixed within the vertical shift registers or within the vertical transfer portions and the horizontal output register, to create a mixed signal charge. Then, the mixed signal charge corresponding to four of the photo/electro conversion portions is transferred within the horizontal output register. Thus, one scanning line is formed by every four rows of the photo/electro conversion portions.

Charge coupled device (CCD) solid-state image sensors comprise a substrate including a plurality of sensor groups. Each sensor group consists of N photodiodes and 2N+1 transfer electrodes, where N is at least two. By providing, for example, two photodiodes and five transfer electrodes in a group, improved area efficiency may be provided along with efficient manufacturing and driving. Three insulated patterned conductive layers are formed on a gate insulating layer, to define the first through fifth transfer electrodes on the transfer region.

A dipping in potential well due to direct contact between transfer electrodes and metal wiring causes a drop in transfer efficiency through a CCD register. In order to eliminate or at least reduce the potential dipping, an N.sup.- -type impurity layer that functions as a CCD channel is formed with N.sup.-- -type impurity regions that have impurity concentration lower than that of the N.sup.- -type impurity layer. The N.sup.- -type impurity regions are located below transfer electrodes in alignment with contact apertures.

Defective sweep occurs when strong light enters, i.e., a quantity of input light increases, and smear and blooming components increase during an exposure period because a quantity of unnecessary charge to be swept during a sweep-out transfer period of a first field side exceeds a quantity of charge to be handled. The inventive image pickup system solves the above-mentioned problem by setting the sweep-out transfer period of the first field side to be longer than the sweep-out transfer period of a second field in a digital still camera which controls an exposure time by using a mechanical shutter in using as an image pickup device, a solid-state image pickup device which carries out the sweep-out transfer of transferring and sweeping charges within a vertical transfer section quickly more than transfer speed in transferring the signal charges read out from a sensor section to the vertical transfer section before reading out the signal charges from the sensor section to the vertical transfer section.