A phosphor thin film of a compound of zinc, cadmium, manganese or alkaline earth metals and an element of group VI is sandwiched by barrier layers having a larger energy gap than that of the phosphor thin film, and a plurality of the sandwich structures are accumulated thicknesswise to constitute...http://www.google.fr/patents/US5700591?utm_source=gb-gplus-shareBrevet US5700591 - Light-emitting thin film and thin film EL device
