Patent ID: 8829784
Filing Date: 2014-09-09
Classification: G02B,H01L

Abstract:
1. A surface light source device comprising: an organic electroluminescent element including a luminescent layer; and a light-emitting surface structure layer disposed on at least one of surfaces of the organic electroluminescent element, wherein: the light-emitting surface structure layer includes a concave-convex structure provided on a surface thereof on a side toward a light-emitting surface of the device, the concave-convex structure includes a plurality of concave portions having oblique surfaces and flat portions disposed around the concave portions, and wherein at least one flat portion or concave portion has a size difference from at least one other flat portion or concave portion respectively, where said size difference is in one or more of a height thereof, and a depth thereof, the size difference being 0.62 times or larger than the center wavelength of one or both of emitted light and reflected light.