Abstract: Electroluminescent device having an active layer of an electroluminescent material situated between two patterns of electrodes at least one of which is transparent to light emitted by the active layer, one of the patterns comprising a material for injecting charge carriers for emission a control for supplying bias voltage across a part of the active layer or setting bias current through the part of the active layer, means for applying a voltage in the reverse direction across part of the active layer, for measuring current associated with voltage applied in the reverse direction and for varying bias voltage or current depending on the measured current value.