Light emitting module and lens

Abstract

A lens including an upper surface having a curved portion having a changing curvature in a direction extending away from a central axis of the lens, and a lower surface having a concave portion disposed on the central axis of the lens. The concave portion of the lower surface includes an entrance disposed on a lower region of the concave portion and configured to receive light emitted from a light-emitting diode chip, and an upper end surface disposed on an upper region of the concave portion. The concave portion includes a width that narrows in a direction extending away from the entrance. The upper end surface is nonplanar.

What is claimed is: 
     
         1 . A light emitting module, comprising:
 a housing comprising a cavity;   a light emitting device comprising a light emitting diode chip disposed in the cavity; and   a wavelength conversion layer which fills the cavity of the housing; and   a lens comprising:
 a first portion comprising a lower surface and a concave portion comprising an entrance region, the concave portion being enclosed by the lower surface and narrowing from the entrance region toward a direction of a central axis, which is perpendicular to the lower surface, 
 a second portion comprising a concave surface disposed on the central axis, and 
 a plurality of legs supporting the lower surface, 
   wherein the wavelength conversion layer is disposed below the lower surface and is enclosed by the housing,   wherein the wavelength conversion layer overlaps a region narrower than the entrance region, and   wherein at least a portion of the housing is disposed outside of the entrance region.   
     
     
         2 . The light emitting module of  claim 1 , wherein the concave portion comprises an upper end surface spaced apart from the lower surface. 
     
     
         3 . The light emitting module of  claim 2 , wherein the upper end surface is flat. 
     
     
         4 . The light emitting module of  claim 3 , a light scattering pattern is disposed on the upper end surface. 
     
     
         5 . The light emitting module of  claim 3 , wherein a material layer having a refractive index greater than that of the lens is disposed on the upper end surface. 
     
     
         6 . The light emitting module of  claim 2 , wherein the upper end surface comprises a surface selected from the group consisting of a downwardly convex surface and an upwardly concave surface. 
     
     
         7 . The light emitting module of  claim 2 , wherein the upper end surface comprises a rounded surface. 
     
     
         8 . The light emitting module of  claim 2 , wherein the second portion of the lens further comprises a convex surface connected to the concave surface. 
     
     
         9 . The light emitting module of  claim 8 , wherein the lens further comprises a flange connected to the convex surface of the second portion and the lower surface of the first portion. 
     
     
         10 . The light emitting module of  claim 9 , wherein an upper portion of the flange is disposed below the upper end surface. 
     
     
         11 . The light emitting module of  claim 10 , wherein the flange comprises a vertical lateral surface. 
     
     
         12 . The light emitting module of  claim 11 , wherein the vertical lateral surface comprises uneven patterns. 
     
     
         13 . The light emitting module of  claim 11 , wherein the vertical lateral surface is connected to the lower surface of the first portion of the lens. 
     
     
         14 . The light emitting module of  claim 11 , wherein the entrance region is elongated in one direction. 
     
     
         15 . The light emitting module of  claim 1 , further comprising a printed circuit board,
 wherein the housing is disposed on the printed circuit board, and   wherein the plurality of legs are connected to the printed circuit board.   
     
     
         16 . The light emitting module of  claim 15 , wherein the printed circuit board comprises an upper surface and a reflective film disposed on the upper surface of the printed circuit board. 
     
     
         17 . The light emitting module of  claim 1 , wherein uneven patterns are formed on the lower surface of the first portion.