MANUFACTURING METHOD FOR COMPOSITE SUBSTRATE, AND COMPOSITE SUBSTRATE AND EL ELEMENT PROVIDED THEREBY

PROBLEM TO BE SOLVED: To provide a manufacturing method for a composite substrate capable of providing high display quality when it is applied to a thin film luminescent element by simply flattening the surface of a thick-film ceramic dielectric layer in a simple manner and at a low cost as compared with a conventional one and by increasing the density thereof, and to provide a composite substrate manufactured thereby and a thin film EL element using it. SOLUTION: This manufacturing method for a composite substrate is so composed that at least an electrode layer and a composite substrate precursor having a dielectric green layer by a thick-film method are formed on a substrate having an electrical insulation property, and the surface of the dielectric green layer is smoothed by rubbing it, and thereafter baked to provide the composite substrate. This composite substrate and this EL element are provided by the manufacturing method.