LED with multilayer light extractor having a refractive index gradient

A light emitting device comprising:

• a first semiconductor layer;
• a second semiconductor layer;
• an active layer provided between the first semiconductor layer and the second semiconductor layer;
• a first light extraction layer provided on the first semiconductor layer, the first light extraction layer including an uneven portion that includes convex and concave portions;
• and
• a second light extraction layer provided between the first light extraction layer and the first semiconductor layer, wherein the convex portions of the first light extraction layer include first layers, wherein the first layers are any one of InAlGaN, AlGaN, or AlN, wherein a refractive index of each of the first layers is decreased with increasing distance from the first semiconductor layer, wherein the second light extraction layer includes second layers and the second layers are any one of InAlGaN, AlGaN, or AlN, wherein each of the second layers is substantially flat and does not include an unevenness, wherein a refractive index in each of the second layers decreases with increasing distance from the first semiconductor layer, wherein at least one concave portion of the first light extraction layer is provided over the second light extraction layer, wherein each of the convex portions has a pyramid structure such that the first layers are laminated, wherein the refractive index of each first layer is different from the refractive indexes of the other first layers, wherein an angle of a side wall of each of the convex portions with respect to an upper surface of the second light extraction layer is 58° to 65°, wherein a thickness of each of the first layers is a multiple of λ/(4*n), and wherein λ is a wavelength of light and n is a refractive index of each of the first layers.

A light emitting device package comprising:

• a package body;
• a first conductive layer and a second conductive layer provided on the package body;
• and
• a light emitting device connected electrically to the first conductive layer and the second conductive layer, wherein the light emitting device includes a first semiconductor layer, a second semiconductor layer, an active layer provided between the first semiconductor layer and the second semiconductor layer, a first light extraction layer provided on the first semiconductor layer and including a nitride semiconductor, and a second light extraction layer provided between the first light extraction layer and the first semiconductor layer and including a nitride semiconductor, wherein the first light extraction layer has protruding portions and concave portions, each protruding portion having a plurality of first layers which are laminated to form a pyramid structure, wherein refractive indexes of the first layers decrease with increasing distance from the first semiconductor layer, wherein the second light extraction layer includes a plurality of second layers, and each of the second layers is substantially flat and does not include an unevenness, and refractive indexes of the second layers decrease with increasing distance from the first semiconductor layer, wherein at least one concave portion of the first light extraction layer is provided over at least one of the second layers, wherein the refractive index of each first layer is different from the refractive indexes of the other first layers, wherein an angle of a side wall of each of the protruding portions with respect to an upper surface of the second light extraction layer is 58° to 65°, wherein a thickness of each of the first layers is a multiple of λ/(4*n), and wherein λ, is a wavelength of light and n is a refractive index of each of the first layers.