To provide an EL element with reduced total reflection not only at the interface between the air layer and a transparent substrate but also at the interface on the light extraction side of the transparent electrode layer, with sufficiently improved light extraction efficiency.
A negative electrode 1, EL layer 2, particle-containing transparent electrode layer 3', low refractive index layer, and translucent substrate 5 such as a glass substrate are laminated in this order. The light from the EL layer 2 is emitted to the transparent electrode layer 3' side in the state of as it is or reflected by the negative electrode and passing through the EL layer 2, and passes through the low refractive index layer 4 and the substrate 5, and extracted. Since the low refractive index layer 4 is provided, the light entered from the transparent electrode layer 3' side to the low refractive index layer side 4 enters the interface between the substrate 5 and low refractive index layer 4 at an incident angle almost perpendicular to the substrate face of the substrate 5, and thereby, total reflection on the air layer 7 side of the transparent substrate 5 decreases.As the transparent electrode layer 3' contains particles. total reflection on interface of low refractive-index layer and particle-containing transparent electrode layer also decreases and the light extraction efficiency is improved.
COPYRIGHT: (C)2005,JPO&NCIPI
Shinji Aramaki
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