PURPOSE: To improve the heat resistance of fluorescent dyestuff and fluorescent pigment, and prevent change of a color tone during a manufacturing process, storage of an element, or driving by processing the fluorescent dyestuff and fluorescent pigment using formalin.
CONSTITUTION: An electroluminescent light emitting element consists of a surface moisture preventing sealing material, a surface electrode having transparency, a light emitting layer, a backing electrode, a lead wire, a back moisture preventing sealing material, and a filter layer if necessary, and the fluorescent dyestuff and/or fluorescent pigment are processed with formalin. In this formalin process to the fluorescent dyestuff and/or fluorescent pigment, the fluorescent dyestuff and/or fluorescent pigment are dispersed in parts for the light emitting layer comprising light emitting material, high dielectric constant binder such as cyanoethyl polyvinyl alcohol or the like, and solvent such as DMA (dimethyl acetamide), and formalin is then added.
SHIMIZU CHIKATOMO
MUKOYAMA HIDEAKI
