US Patent 7888864 Electroluminescent devices and their manufacture

An EL device comprising a substrate (11), a light emissive structure comprising three series connected LEDs on the substrate (LED 1, 2, 3). Considering the diode LED1, it comprises organic light emissive material disposed (16-1) between an underlying ITO anode (12-1) and an overlying cathode (17-1) that is electrically connected in series to the underlying anode (12-2) of the diode LED2 through the thickness of the organic light emissive material (16-1). The connection can be made by using a wetting agent to prevent the organic light emissive material disposed (16-1) covering contact region (19-1) on the anode (12-2) so that the overlying cathode (17-1) can make a series connection with the underlying anode (12-2).