The present invention relates to an optical substrate comprising a transparent substrate, a low refractive index layer, whose refractive index is lower than that of the transparent substrate, disposed over the transparent substrate, and a solgel film disposed over the low refractive index layer; a light emitting element having a first electrode, a light emitting layer and a second electrode over the solgel film of this optical substrate; and a display device provided with this light emitting element.