Color stable red-emitting phosphors
A lighting apparatus includes a semiconductor light source in direct contact with a polymer composite comprising a color stable Mn 4+ doped phosphor, wherein the lighting apparatus has a color shift of ≤1.5 MacAdam ellipses after operating for at least 2,000 hour at a LED current density greater than 2 A/cm 2 , a LED wall-plug efficiency greater than 40%, and a board temperature greater than 25° C.
1. A lighting apparatus comprising a semiconductor light source; and
a color stable M 4+ doped phosphor of formula K 2 SiF 6 :Mn 4+ , wherein % intensity loss of the phosphor after exposure to light flux of at least 80 w/cm 2 at a temperature of at least 50° C. for at least 8 hours is ≤4%.
2. The lighting apparatus according to claim 1 , wherein % intensity loss of the phosphor is ≤3%.
3. The lighting apparatus according to claim 1 , wherein % intensity loss of the phosphor is ≤1%.
4. A backlight device comprising a semiconductor light source; and
a color stable Mn 4+ doped phosphor of formula K 2 SiF 6 :Mn 4+ , wherein % intensity loss of the phosphor after exposure to light flux of at least 80 w/cm 2 at a temperature of at least 50° C. for at least 8 hours is ≤4%.
5. The backlight device according to claim 4 , wherein % intensity loss of the phosphor is ≤3%.
6. The backlight device according to claim 4 , wherein % intensity loss of the phosphor is ≤1%.
7. A color stable Mn 4+ doped phosphor of formula K 2 SiF 6 :Mn 4+ , wherein % intensity loss of the phosphor after exposure to light flux of at least 80 w/c 2 at a temperature of at least 50° C. for at least 8 hours is ≤4%.
8. The color stable Mn 4+ doped phosphor according to claim 7 , wherein the % intensity loss of the phosphor is ≤3%.
9. The color stable Mn 4+ doped phosphor according to claim 7 , wherein the % intensity loss of the phosphor is ≤1.5%.