Light Emitting Device, Light Emitting Device Package

Abstract

Provided are a light emitting device, a light emitting device package, and a lighting system. The light emitting device includes a light emitting structure including a first conductive type semiconductor layer, a second conductive type semiconductor layer, and an active layer between the first conductive type semiconductor layer and the second conductive type semiconductor layer and a light extraction pattern in which a period (a) exceeds λ/n (where, λ is a wavelength of light emitted from the active layer, and n is a refractive index of the light emitting structure) on the light emitting structure. The period (a) may be in the range of 5×(λ/n) (a (15×(λ/n). An etching depth (h) of the light extraction pattern may be equal to or greater than λ/n.

1 . A light emitting device comprising:
 a light emitting structure including a first conductive semiconductor layer, a second conductive semiconductor layer and an active layer interposed between the first and second conductive semiconductor layers; and   a light extraction pattern on the light emitting structure and having a period (a) of λ/n or above (λ is a wavelength of light emitted from the active layer and n is a refractive index of the light emitting structure),   wherein the period (a) is in a range of 5×(λ/n)<a<15×(λ/n), and   an etching depth (h) of the light extraction pattern is λ/n or above.   
     
     
         2 . The light emitting device as claimed in  claim 1 , further comprising an undoped semiconductor layer on the light emitting structure, wherein the light extraction pattern is on the undoped semiconductor layer. 
     
     
         3 . The light emitting device as claimed in  claim 1 , wherein the etching depth (h) of the light extraction pattern is 450 nm to 900 nm. 
     
     
         4 . The light emitting device as claimed in  claim 1  or  3 , wherein the period (a) of the light extraction pattern is 1000 nm to 2800 nm. 
     
     
         5 . A light emitting device comprising:
 a light emitting structure including a first conductive semiconductor layer, a second conductive semiconductor layer and an active layer interposed between the first and second conductive semiconductor layers; and   a second electrode layer supporting the light emitting structure; and   a light extraction pattern on the second electrode layer and having a period (a) of λ/n or above (λ is a wavelength of light emitted from the active layer and n is a refractive index of the light emitting structure),   wherein the light extraction pattern is formed in the second electrode layer while making contact with the light emitting structure without being exposed out of the second electrode layer.   
     
     
         6 . The light emitting device as claimed in  claim 5 , wherein the period (a) is in a range of 5×(λ/n)<a<15×(λ/n). 
     
     
         7 . The light emitting device as claimed in  claim 5 , wherein an etching depth (h) of the light extraction pattern is λ/n or above. 
     
     
         8 . The light emitting device as claimed in  claim 5 , wherein the period (a) of the light extraction pattern is 1000 nm to 2800 nm. 
     
     
         9 . The light emitting device as claimed in  claim 5 , further comprising a wavelength filter on the light emitting structure. 
     
     
         10 . The light emitting device as claimed in  claim 9 , wherein the wavelength filter comprises a first dielectric layer having a first refractive index and a second dielectric layer having a second refractive index. 
     
     
         11 . The light emitting device as claimed in  claim 10 , wherein the first and second dielectric layers have a thickness of about λ/(4n×cos θ) (λ is a wavelength of light emitted from the active layer, n is a refractive index of the dielectric layers, and θ is an incident angle of light with respect to a substrate). 
     
     
         12 . The light emitting device as claimed in  claim 10 , wherein the second dielectric layer is stacked on the first dielectric layer and the first refractive index is lower than the second refractive index. 
     
     
         13 . A light emitting device package comprising:
 a light emitting device claimed in any one of  claims 1  and  5 ; and   a package body in which the light emitting device is installed.