Patent ID: 8338847

Claim:
A light emitting device comprising: a first semiconductor layer; an active layer to generate a light on the first semiconductor layer; a second conductive semiconductor layer on the active layer; a transparent electrode layer on the second conductive semiconductor layer; and a multiple thin film mirror on the transparent electrode layer, the multiple thin film mirror being formed by repeatedly stacking a first thin film layer having a first refractive index and a second thin film layer having a second refractive index different from the first refractive index by at least one time, wherein the second conductive semiconductor layer has a thickness satisfying following equation 1: 2·Φ1+Φ2 =N· 2π±Δ, (0≦Δ≦π/2) Equation 1 wherein, Φ1 is a phase shift occurring when a light, which travels in a vertical direction, passes through the second conductive semiconductor layer and is expressed as Φ1=2πnd/λ (n is a refractive index of the light, λ is a wavelength of the light, and d is a thickness of the second conductive semiconductor layer), Φ2 is a phase shift occurring when the light is reflected from one of the transparent electrode layer and the multiple thin film mirror, and N is a natural number.