An electroluminescent (EL) display device comprises an array of display pixels,
each display pixel comprising an EL display element and a driving circuit. A digital
pixel drive signal determines whether the pixel is on or off, and a selected one
of a plurality of supply voltages is switched to the EL display element. This device
enables a digital drive scheme to be implemented, but the provision of a plurality
of different supply voltages enables a grey scale to be implemented without requiring
time or area ratio systems to be employed. Alternatively, the device of the invention
can allow time or area ratio techniques to be improved.
