Patterning an electroluminescent device by exposure to ultraviolet radiation

An electroluminescent (EL) device which may be encapsulated in a hermetically sealed package is fabricated and then the light-emitting layer (7), which is preferably a molecular organic or organo-metallic material, is exposed to ultraviolet (UV) light (1) to reduce the emissivity of the UV-exposed portions of layer (7). The exposure may occur through mask (2) to pattern the device by attenuating the UV light (1) to create variations in the luminescence. Following exposure to UV light (1) the device may be protected from further UV exposure by coating the surfaces with material opaque to UV light to prevent degradation. The EL device may include top electrode (9), transparent electrode (5), optional hole and electron-injecting or transport layers (6,8) on transparent substrate (4). A light crystal display may be placed behind the EL device.