An OLED display, comprising: a) a substrate; b) a plurality of
independently controlled light emitting elements formed on the substrate,
the light emitting elements having an output that changes with time or
use; c) a plurality of active-matrix circuits formed on the substrate for
driving the light-emitting elements wherein the performance of some
portion of the active matrix circuitry is altered in response to incident
radiation, and wherein an incident light absorbing or reflecting layer
prevents light from irradiating the portion responsive to incident
radiation; d) a current measuring device for sensing the total current
used by the display to produce a current signal; and e) a controller
responsive to the current signal for calculating a correction signal for
the light emitting elements and applying the correction signal to input
image signals to produce corrected input image signals that compensate
for the changes in the output of the light emitting elements.