| 摘要 |
PROBLEM TO BE SOLVED: To provide a thin type EL element by which a crack and separation or the like are not developed in a light emitting layer and which is excellent in element performance in an annealing process in manufacturing when an alkaline earth metal sulfide is used in the light emitting layer of a thin film EL element. SOLUTION: The thin film EL element is formed by layering a thin film on a light transmissive substrate 1 in order of a transparent electrode 2, an insulating layer 3, a light emitting layer 4, an insulating layer 5 and a back plate 6. When SrS of an alkaline earth metal sulfide is used as a base material of the light emitting layer of this thin film EL element, a thermal expansion coefficient of the light transmissive substrate 1 is set in a range of 8×10<-6> / deg.C to 12×10<-6> / deg.C. Therefore, stress generated by a difference in a thermal expansion coefficient between the alkaline earth metal sulfide and the light transmissive substrate is reduced, and the development of a crack and separation of the light emitting layer 4 can be prevented.
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