SURFACE LIGHT SOURCE DEVICE

摘要

Disclosed is a surface light source device provided with: an organic EL element which comprises a light-emitting face and emits light from the light-emitting face; and an optical output face structural layer which is provided on the light-emitting face of the organic EL element, wherein relatively recessed concave sections and relatively projecting convex sections are alternately provided in the surface of the optical output face structural layer, at the side opposing the organic EL element and in the in-plane direction parallel to the surface. Distances in the thickness direction of the surface light source device, between the bottoms of the concave sections and the tip ends of the adjacent convex sections, are irregular in a range in which the standard deviation is 0.05 µm or more.