White emitting light source and luminescent material
View Patent ↗The invention relates to a white emitting light source with an improved luminescent material of the formula (AEN2/3)*b(MN)*c(SiN4/3)*d1CeO3/2*d2EuO*xSiO2*yAlO3/2 wherein AE is an alkaline earth metal chosen of the group of Ca, Mg, Sr and Ba or mixtures thereof and M is a trivalent element chosen of the group of Al, B, Ga, Sc with d1>10*d2. In combination with a UV to blue light generating device this material leads to an improved light quality and stability, especially an improved temperature stability for a wide range of applications.
1. A device comprising:
a light source configured to emit light having a wavelength between 400 nm and 480 nm; and
a luminescent material positioned to absorb light emitted by the light source, the luminescent material comprising (AEN 2/3 )*b(MN)*c(SiN 4/3 )*d 1 CeO 3/2 *d 2 EuO*xSiO 2 *yAlO 3/2 wherein AE is an alkaline earth metal chosen of the group of Ca, Mg, Sr and Ba or mixtures thereof and M is a trivalent element chosen of the group of Al, B, Ga, Sc or mixtures thereof, wherein
0.95≦2*( a+d 1 +d 2 )/( b+c+x+y )≦1.2
a+d 1 +d 2 ≧c+x,
( b+y ):( c+x )≧1,
( b+y )≦1+10* d 1 ,
b≧ 5* y,
c≧ 10* x,
0.0001 ≦d 1 ≦0.2 and d 1 ≧10* d 2 .
2. The device of claim 1 , wherein d 1 is ≧0.01% and ≦20% of a.
3. The device of claim 1 , wherein (b+y):(c+x) is ≧1.01 and ≦1.20.
4. The device of claim 1 , wherein (b+y) is ≦1+10*d 1 .
5. The device of claim 1 , wherein b≧5*y and c≧10*x.
6. The device of claim 1 , wherein d 1 is ≦0.01.
7. The device of claim 1 wherein the luminescent material emits light having a wavelength between 500 nm and 700 nm.
8. The device of claim 1 wherein combined light comprising light emitted by the light source and light emitted by the luminescent material has a correlated color temperature between 3000 and 4000 K.
9. The device of claim 1 , wherein in said at least one luminescent material [Ba]+[Sr]+[Mg] is ≦0.9*[Ca].
10. The device of claim 1 , wherein the light source is a light emitting diode.
11. A device comprising:
a light source; and
a ceramic luminescent material positioned to absorb light emitted by the light source, the luminescent material comprising (AEN 2/3 )*b(MN)*c(SiN 4/3 )*d 1 CeO 3/2 *d 2 EuO*xSiO 2 *yAlO 3/2 wherein AE is an alkaline earth metal chosen of the group of Ca, Mg, Sr and Ba or mixtures thereof and M is a trivalent element chosen of the group of Al, B, Ga, Sc or mixtures thereof, wherein
0.95≦2*( a+d 1 +d 2 )/( b+c+x+y )≦1.2
a+d 1 +d 2 ≧c+x,
( b+y ):( c+x )≧1,
( b+y )≦1+10* d 1 ,
b≧ 5* y,
c≧ 10* x,
0.0001 ≦d 1 ≦0.2 and d 1 ≧10* d 2 .
12. The device of claim 11 , wherein d 1 is ≧0.01% and ≦20% of a.
13. The device of claim 11 , wherein (b+y):(c+x) is ≧1.01 and ≦1.20.
14. The device of claim 11 , wherein (b+y) is ≦1+10*d 1 .
15. The device of claim 11 , wherein b≧5*y and c≧10*x.
16. The device of claim 11 , wherein d 1 is ≦0.01.
17. The device of claim 11 , wherein the light source is a light emitting diode that emits blue light.
18. The device of claim 11 , wherein the ceramic luminescent material has a density ≧90% of a theoretical density.
19. The device of claim 11 , wherein:
the ceramic luminescent material comprises a main constituent and pores;
the ceramic luminescent material has a volume density larger than 90 percent of the main constituent; and
the main constituent is more than 80 percent single crystal domains.
20. The device of claim 11 , wherein the ceramic luminescent material has a surface with an RMS roughness ≧0.001 μm and ≦1 μm.