Multi-grain luminescent ceramics for light emitting devices

Abstract

A ceramic body is disposed in a path of light emitted by a light source. The light source may include a semiconductor structure comprising a light emitting region disposed between an n-type region and a p-type region. The ceramic body includes a plurality of first grains configured to absorb light emitted by the light source and emit light of a different wavelength, and a plurality of second grains. For example, the first grains may be grains of luminescent material and the second grains may be grains of a luminescent material host matrix without activating dopant.

1 - 9 . (canceled) 
     
     
         10 . The device of  claim 26  wherein:
 the first grains comprise a host matrix and a first activating dopant; and 
 the second grains comprise the host matrix and a second activating dopant. 
 
     
     
         11 . The device of  claim 26  wherein the second grains are configured to absorb the first light and emit a third light of a different wavelength from the first light and the second light. 
     
     
         12 . The device of  claim 26  wherein the ceramic body further comprises third grains comprising the host matrix without any activating dopant. 
     
     
         13 . The device of  claim 26  wherein:
 the first activating dopant is Ce; and 
 the second activating dopant is Eu. 
 
     
     
         14 . The device of  claim 26  wherein the host matrix is Ca 1−x−y M y Al 1+a−b+x B b Si 1−a N 3−a O a , where M=(Mg, Sr, Ba), B=(B, Ga), 0.001≦x≦0.02, 0≦y≦1, 0.0005≦a≦1, 0≦b≦1. 
     
     
         15 . The device of  claim 26  wherein the host matrix is (Lu 1−x−y−a−b Y x Gd y ) 3 (Al 1−z−u Ga z Si u ) 5 O 12−u N u  wherein 0≦x≦1, 0≦y≦1, 0<z≦0.1, 0≦u≦0.2, 0<a≦0.2 and 0<b≦0.1. 
     
     
         16 - 25 . (canceled) 
     
     
         26 . A device comprising:
 a light source; and   a ceramic body disposed in a path of a first light emitted by the light source, wherein the ceramic body comprises:
 a plurality of first grains configured to absorb the first light emitted by the light source and emit a second light of a different wavelength from the first light; and 
 a plurality of second grains; 
 wherein the light source comprises a semiconductor structure comprising a light emitting region disposed between an n-type region and a p-type region.