| 摘要 |
PROBLEM TO BE SOLVED: To provide an organic electroluminescence(EL) element having high luminescence efficiency (light extraction efficiency), and low power consumption in high luminosity. SOLUTION: The light, which is generated within the organic EL element, has two courses of the light (1), which directly goes ahead of the element, and the light (2), which goes ahead of the element after reflecting from a negative electrode 15. Since there is light pass difference, these light interfere mutually. The phase differenceδbetween the light, which comes out from a luminescence layer and goes directly ahead of the element, and the light, which reflected by the negative electrode, is obtained byδ=π+4πL/λconcerning to the normal direction of a substrate, in whichλis wavelength, and L is an optical distance from a light emitting position to a reflective face. The optical distance L is given by an optical film thickness nd of an organic material which exists in from the luminescence position to the reflecting face (n is a refractive index and d is a film thickness). When the organic material, which exists from the luminescence position to the reflecting face, consists of a plurality of the layers, the optical distance L is given as the sum of the optical distance (optical film thickness) of each the organic layers.
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