g such a construction, the amount of light incident atangles less than the critical angle is increased, resulting in an increase in external extraction efficiency.The light-scattering layer 9 is prepared by dispersing SiO.sub.2 (refractive index: about 1.5) or the like in a polymer such as polymethyl methacrylate (PMMA, refractive index: about 1.7) or polycarbonate (PC, refractive index: about 1.7