Patent ID: 9431632
Filing Date: 2016-08-30
CPC Classification: G02B,G02F,H01L

Claim Text:
1. A surface light source device, comprising: an organic electroluminescent element including a luminescent layer; and a light-emitting surface structure layer disposed in contact with 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, the surface light source device further comprises a first diffusing member and a second diffusing member on which light emitted from the luminescent layer is incident, the first diffusing member is provided as a layer constituting all or part of the light-emitting surface structure layer, and is a member that allows the incident light to pass through in a diffused manner, and the second diffusing member is disposed at a position farther from the light-emitting surface structure layer than the organic electroluminescent element, and is a member that reflects the incident light in a diffused manner.