Patent ID: 8075148

Claim:
An illumination apparatus, comprising: a transparent substrate including oppositely facing first and second surfaces; a phosphor layer disposed on a first surface side of the transparent substrate; an optical wavelength selection filter layer disposed on a second surface side of the transparent substrate and configured to transmit light of a first wavelength therethrough and reflect light of a second wavelength that is emitted from the phosphor layer by being excited by the light of the first wavelength; and a light-emitting device configured to emit the light of the first wavelength toward the optical wavelength selection filter layer, wherein, the optical wavelength selection filter layer is between the transparent substrate and the light-emitting device, the optical wavelength selection filter layer includes at least a first film and a second film, and the first film is in contact with the second surface of the transparent substrate, the first film having a greater refractive index than the second film.