Patent ID: 7221342

Claim:
An active matrix electroluminescent (EL) display device comprising a matrix array of electroluminescent display elements each of which has an associated switching circuit for controlling the current through the display element in accordance with an applied drive signal, wherein the switching circuit comprises: a drive transistor and a cascode transistor in series with an associated EL display element, the drive transistor being for driving a current through the associated EL display element and the cascode transistor being connected between the drive transistor and the associated EL display element; a storage capacitor connected between a power supply line to which the source of the drive transistor is also directly connected and the gate of the drive transistor, for storing a gate voltage for the drive transistor; and a first switch for allowing or preventing the drive current to flow through the EL display element, wherein the first switch is connected between the cascode transistor and the associated display element; wherein the switching circuit is operable in two modes, a first mode in which an input current is sampled by the drive transistor and the first switch is open, and a second mode in which the drive transistor drives a current corresponding to the input current through the EL display element, and the first switch is closed.