Patent ID: 8704253

Claim:
An organic EL (electroluminescence) light-emitting device comprising: a structure including, arranged in this order, a substrate, a first electrode, an organic EL layer and a second electrode opposed to the first electrode; and an unevenness which has a period for converting a waveguide mode to a radiation mode and inhibiting a propagation of light in a waveguide mode, the unevenness arranged in a single one of an interior of the substrate, an interior of the first electrode, an interior of the organic EL layer, an interior of the second electrode, a boundary between the substrate and an exterior of the substrate, a boundary between the substrate and the first electrode, a boundary between the first electrode and the organic EL layer, a boundary between the organic EL layer and the second electrode and a boundary between the second electrode and an exterior of the second electrode, wherein the second electrode is a transparent electrode, an at least translucent thin film metal electrode or an electrode comprised of a transparent electrode and an at least translucent thin film metal arranged on a side of the transparent electrode nearest to the organic EL layer, the unevenness is an optical structure having a regularity of a refractive index distribution in a one-dimensional, two-dimensional or three-dimensional direction, a refractive index of an interior of the optical structure is different from a refractive index of a periphery of the optical structure, the regularity has a fluctuation of not more than one fourth of a period of an effective wavelength degree of the light emitted from the organic EL layer, and the unevenness has at least two optical structures with the regularity of the refractive index distribution in the two-dimensional direction, and the regularity of the optical structures has a different period within a fluctuation range for each optical structure.