Patent ID: 7759861

Claim:
An organic EL display comprising: a transparent substrate having a surface; an organic EL element provided on or above the surface of the transparent substrate and including a transparent electrode disposed on or beside the surface of the transparent substrate; a two-dimensional concavo-convex structure provided on the surface of the transparent substrate, having two kinds of pattern periods and first and second types of convex structures where said first type of convex structure has an area smaller than an area of said second type of convex structure, and being provided in a pattern adapted for each of R, G and B light; and a buffer layer disposed between said transparent electrode and said concavo-convex structure, wherein a refractive index of said transparent electrode is approximately the same as a refractive index of said buffer layer, wherein one of the two kinds of pattern periods corresponds to light with a wavelength of 600 nm to 700 nm, and the other of the two kinds of pattern periods corresponds to light with a wavelength of 350 nm to 460 nm, and wherein the concavo-convex structure includes a first concavo-convex structure in which convex and concave portions are arranged at pattern points of a first square pattern and a second concavo-convex structure in which convex and concave portions are arranged at pattern points of a second square pattern, an averaged X-directional interval of the first square pattern component being equal to an averaged Y-directional interval of the first square pattern component, an averaged X-directional interval of the second square pattern component and an averaged Y-directional interval thereof being substantially equal to the X-directional interval of the first square pattern component and the Y-directional interval thereof, the second square pattern component being deviated from the first square pattern component by substantially half a pattern period of the first square pattern component in an X-direction and a Y-direction.