Patent ID: 7839365

Claim:
An active matrix electroluminescent display device including an array of display pixels, comprising: an electroluminescent (EL) display element; active matrix circuitry including first and second drive transistors for driving a current through the display element, wherein the first and second drive transistors are in parallel, each connected between a respective power supply line and the EL display element, the input to the pixel being provided to the gates of the first and second drive transistors, and wherein the first drive transistor is supplied with a first supply voltage and the second drive transistor is supplied with a second supply voltage, at least one of the supply voltages being variable in dependence on the combined brightness level; means for determining a combined brightness level of a multitude of pixels in an image to be displayed in a frame period; and means for controlling the first and second drive transistors of each pixel individually in dependence on a respective input signal providing a drive level for the pixel and in dependence on the combined brightness level of the multitude of pixels in the image, wherein the means for controlling the first and second drive transistors comprises a signal processing device for determining an combined brightness level and for processing the input signals for the pixels in dependence on the combined brightness level, wherein the signal processing device is adapted to employ gamma characteristics for processing the input signals in dependence on the combined brightness level, wherein said gamma characteristics comprising a gamma correction LUT altered by a LUT generator to set a certain maximum brightness level depending on the combined brightness level.