Abstract: An active matrix display device comprises an array of display pixels provided over a common substrate (60). Each pixel has an upwardly emitting current-driven light emitting display element (2) comprising a lower electrode (74) and an upper substantially transparent electrode (80a. A light sensitive device (27) for sensing the display element (2) light output is positioned between the substrate (60) and the display element (2), and a drive transistor (22) is controlled in response to the light-sensitive device (27) output. The lower electrode (74) of the display element is partially transmissive to transmit at most 20% of the light incident on the lower electrode, at least a portion of the transmitted light being directed to the underlying light-sensitive device (27).