Tri-color white light led lamp

Abstract

The invention relates to a tri-color lamp for generating white light comprising a phosphor composition comprising a phosphor of general formula (Ba 1-x-y-z- Sr x Ca y ) 2 SiO 4 :Eu z , wherein 0≦x≦1, 0≦y≦1 and 0<z<1. The phosphor composition may also comprise a red phosphor. The two phosphors can absorb radiation emitted by a light emitting diode, particularly a blue LED. This arrangement provides a mixing of three light sources—light emitted from the two phosphors and unabsorbed light from the LED. The invention also relates to an alternative to a green LED comprising a single green phosphor of general formula (Ba 1-x-y-z- Sr x Ca y ) 2 SiO 4 :Eu z , wherein 0≦x≦0 1, 0≦y≦1 and 0<z<1, that absorbs radiation from a blue LED. A resulting device provides green light of high absorption efficiency and high luminous equivalent values.

1 . A light emitting device comprising a LED for emitting a pattern of light and a phosphor composition comprising a phosphor of general formula (Ba 1-x-y-z Sr x Ca y ) 2 SiO 4 :Eu z , wherein 0≦x≦1, 0≦y≦1 and 0<z<1. 
   
   
       2 . The light emitting device according to  claim 1 , wherein the light emitting device has an emission at a wavelength from 450 nm to 480 nm. 
   
   
       3 . The light emitting device according to  claim 1 , wherein the phosphor composition is comprised in a thin film layer. 
   
   
       4 . The light emitting device according to  claim 1 , wherein the LED is a blue-emitting LED. 
   
   
       5 . The light emitting device according to  claim 1 , wherein the phosphor composition comprises a green phosphor of general formula (Ba 1-x-y-z Sr x Ca y ) 2 SiO 4 :Eu z , wherein 0≦x≦1, 0≦y≦1 and 0<z<1 and a red phosphor. 
   
   
       6 . The light emitting device according to  claim 5 , wherein the red phosphor is selected from the group of (Sr 1-x-y Ba x Ca y )S:Eu wherein 0≦x<1 and 0≦y<1; CaS:Ce, Cl; Li 2 Sr SiO 4 :Eu; (Sr 1-x Ca x )SiO 4 :Eu wherein 0≦x<1; (Y 1-x Gd x ) 3 (Al 1-y Ga y ) 5 O 12 :Ce wherein 0≦x<1 and 0≦y<1 and (Sr 1-x-y Ba x Ca y ) 2 Si 5 N 8 :Eu wherein 0≦x<1 and 0≦y<1. 
   
   
       7 - 9 . (canceled) 
   
   
       10 . A light emitting device comprising a LED for emitting a pattern of light and a phosphor composition comprising a phosphor of general formula (Ba 1-x-y Sr x Ca y ) 2 SiO 4 :Eu z , wherein 0≦x≦1, 0≦y≦1 and 0<z<1. 
   
   
       11 . The light emitting device according to  claim 10 , wherein the LED has an emission at a wavelength from 450 nm to 480 nm. 
   
   
       12 . The light emitting device according to  claim 10 , wherein the phosphor composition is comprised in a thin film layer. 
   
   
       13 . The light emitting device according to  claim 10 , wherein the LED is a blue-emitting LED. 
   
   
       14 . The light emitting device according to  claim 10 , wherein the phosphor composition comprises a red phosphor. 
   
   
       15 . The light emitting device according to  claim 14 , wherein the red phosphor is selected from the group of (Sr 1-x-y Ba x Ca y )S:Eu wherein 0≦x<1 and 0≦y≦1; CaS:Ce, Cl; Li 2 Sr SiO 4 :Eu; (Sr 1-x Ca x )SiO 4 :Eu wherein 0≦x<1; (Y 1-x Gd x ) 3 (Al 1-y Ga y ) 5 O 12 :Ce wherein 0≦x<1 and 0≦y<1 and (Sr 1-x-y Ba x Ca y ) 2 Si 5 N 8 :Eu wherein 0≦x≦1 and 0≦y<1.