Patent attributes
An illumination device comprising an organic light-emitting diode (1) (OLED) having a light output that changes with use with an illumination/active area (2,3), where light is being emitted for an illumination purpose, a reference area (4) being substantially smaller than the illumination area (2), wherein the reference area (4) is an isolated area (4) not connected to the illumination/active area (2,3), a substrate, on which the reference area (4) and the illumination/active area (2,3) are located, a driver (5) connected to the illumination/active area (2,3) and the reference area (4), with a measurement circuit (6) detecting at least one active value of the illumination/active area (2,3) and at least one reference value of the reference area (4), a control circuit (7), which compares the active and the reference value and produces a correction signal in response thereto to compensate the changes in the light output of the illumination area (2), wherein the control circuit (7) calculates the correction signal for the illumination area (2) based on the active value and the reference value.
