PURPOSE: To reduce the drive voltage and also, improve the long-term reliability of light emitting properties.
CONSTITUTION: A lower electrode 3, a lower insulating layer 4, an EL light emitting layer 5, an upper insulating layer 6, and an upper electrode 7 are stacked in this order on the surface 2a of a transparent substrate 2. For the insulating layers 4 and 6, The first insulating layers 4a and 6a consisting of the Si3N4 being the material to prevent the diffusion of impurities to an EL light emitting layer 5, the second insulating layers 4b and 6b consisting of SrTiO3 or CaTiO3 being high permittivity materials, and the third insulating layers 4c and 6c are stacked in order from the side of the EL light emitting layer 5. Since the diffusion of ions are prevented by the Si3N4 films being the first insulating layers 4a and 6a, it becomes possible to use high permittivity material as the second insulating layers 4b and 6b, and the drive voltage drops, and the drop of light emitting properties lessens, and long-term reliability improves.
OGURA TAKASHI
TANAKA KOICHI
