a thickness of around 200 u03bcm and the plastic sheet has a thickness of around 200 u03bcm after formation of the composite structure cs a layer of indium tin oxide 6 is deposited on the inner surface of the glass layer 4 subsequently an electroluminescent layer of poly phenylene vinylene ppv is deposited by spin coating a precursor to ppv in a suitable solvent onto the ito layer 6 and then heating the spin coated layer to convert the precursor to the polymer ppv a subsequent electroluminescent layer or charge transport layer 10 is put down in a similar fashion finally a layer of ca is evaporated followed by the evaporation of an al capping layer alternatively these layers could be deposited by sputtering sequentially or by sputtering a ca al alloy directly according to another embodiment of the invention the structure of fig1 is formed by a process in which the sequence of steps is varied prior to forming the composite structure cs the layer of glass 4 is coated on its surface with a layer of indium tin oxide 6 and after that process the plastic layer 2 is laminated to the underside of the glass layer 4 subsequent steps for manufacture of the device are as described above with reference to the first embodiment fig2 represents a different structure in accordance with the invention in that structure the composite structure still comprises a layer of plastic 2 and a layer of glass.