US Patent 7683378 Light emitting diode and method for fabricating same

An AlGaInP based light emitting diode is provided with a distributed Bragg reflector comprising a combination of an AlGaAs layer and an AlInP layer, each having a film thickness determined by following formulas (1) to (3):t1={λ0/(4×n1)}×α  (1),t2={λ0/(4×n2)}×(2−α)  (2), and0.5<α<0.9  (3)wherein t1 is a film thickness [nm] of the AlGaAs layer, t2 is a film thickness [nm] of the AlInP layer, λ0 is a wavelength [nm] of a light to be reflected, n1 is a refractive index of the AlGaAs layer to the wavelength of the light to be reflected, and n2 is a refractive index of the AlInP layer to the wavelength of the light to be reflected.