Patent ID: 7179672

Claim:
A light-emitting device having a finely roughened structure on a surface of an inorganic light permeable layer formed on a surface of an outermost layer of a light-emitting side or on an outermost layer at a light-emitting side of a semiconductor layer constituting the light-emitting element, the surface having a surface property comprising following two conditions: (1) a mean radius of gyration <R> of projections in the roughened surface structure is 1/20 or more and ½ or less of a light wavelength, and dispersion σ R of a radius of gyration is 1.05 or more and 2 or less, wherein <R> is represented by <R>=ΣR 2 n R /ΣRn R where n R denotes a number of projections having an arbitrary radius of gyration, and σ R is represented by σ R =<R>/(ΣRn R /Σn R ) where n R denotes a number of projections having an arbitrary radius of gyration; and (2) a mean height <H> of projections in the roughened surface structure is 1/10 or more and 1 or less of the light wavelength, and dispersion σ H of the radius of gyration is 1.05 or more and 2 or less, wherein <H> is represented by <H>=ΣH 2 n H /ΣHn H where n H denotes the number of projections having an arbitrary height, σ H is represented by σ H =<H>/(ΣHn H /Σn H ) where n H denotes the number of projections having an arbitrary height.