The invention provides an active matrix type display device which realizes
an image display of multiple gray scale exhibiting high numerical aperture
and high definition with a least number of wiring by having an image
memory circuit equivalent to a static memory circuit without using two
voltages, that is, high and low voltages. Pixels are arranged at portions
where a plurality of scanning lines (selection signal lines) and a
plurality of signal lines (data lines (video signal lines)) intersect each
other, each pixel is comprised of a pixel electrode, a switching element
which selects the pixel electrode and a memory circuit which stores data
to be written in the pixel electrode, and a power supply line which
applies an AC voltage to the memory circuit is provided.
