LED design of lower CCT utilizing PFS phosphor
An LED assembly includes an LED light source having a first light output with a characteristic spectrum, and a yellow-green phosphor, red phosphor, and neodymium fluorine absorber combination through which the first light output passes, wherein the yellow-green phosphor, red phosphor, and neodymium fluorine absorber combination is configured to convert the first light output to a second light output having a predetermined correlated color temperature.
1. An LED assembly, comprising:
an LED light source having a first light output with a characteristic spectrum; and
a yellow-green and red phosphor combination deposited on a top surface of the LED light source, wherein the combination converts the first light output to a second light output with a first correlated color temperature and a first Lighting Preference Index;
wherein an addition of neodymium fluorine absorber in a powdered form to the yellow-green and red phosphor combination and deposited onto the LED light source forms a yellow-green phosphor, red phosphor, and neodymium fluorine absorber combination and results in a third light output with a second correlated color temperature lower than the first correlated color temperature, the second correlated color temperature in the range of 4000 K to 2700 K,
and a second Lighting Preference Index of at least 110 and higher than the first Lighting Preference Index,
the third light output with chromaticity color coordinates below a black body locus in the CIE 1931 color space chromaticity diagram.
2. The LED assembly of claim 1 , wherein the yellow-green phosphor, red phosphor, and neodymium fluorine absorber combination is configured to provide the third light output with a Lighting Preference Index of at least 120.
3. The LED assembly of claim 1 , wherein the neodymium fluoride absorber is configured to attenuate a yellow light emission to provide the second light output with the particular Lighting Preference Index.
4. The LED assembly of claim 1 , wherein the LED light source comprises one or more of a blue LED or a violet LED.
5. The LED assembly of claim 1 , wherein the yellow-green phosphor comprises a garnet phosphor.
6. The LED assembly of claim 5 , wherein the garnet phosphor comprises a yttrium aluminum garnet phosphor.
7. The LED assembly of claim 5 , wherein the garnet phosphor comprises a yttrium aluminum garnet phosphor activated by cerium.
8. The LED assembly of claim 1 , wherein the red phosphor comprises a manganese-doped potassium fluoro-silicate phosphor.
9. The LED assembly of claim 1 , wherein the neodymium fluorine absorber comprises NdF 3 .
10. The LED assembly of claim 1 , wherein the neodymium fluorine absorber comprises a combination of NdF 3 and another neodymium compound.
11. The LED assembly of claim 1 , wherein the neodymium fluorine absorber comprises a combination of NdF 3 and NdOF.
12. The LED assembly of claim 1 , wherein the neodymium fluorine absorber comprises a combination of NdF 3 and Nd 2 O 3 .
13. The LED assembly of claim 1 , wherein the neodymium fluorine absorber is configured to absorb yellow light in a range of approximately 560-610 nm.
14. The LED assembly of claim 1 , wherein the yellow-green phosphor, red phosphor, and neodymium fluorine absorber combination comprises a yellow-green phosphor and red phosphor portion proximate the LED light source and a neodymium fluorine absorber portion spaced apart from the LED light source.
15. The LED assembly of claim 1 , wherein the first correlated color temperature is approximately 4000 K, the first Lighting Preference Index is approximately 111, the second correlated color temperature is approximately 3500 K, and the second Lighting Preference Index is approximately 128.
16. The LED assembly of claim 1 , wherein the first correlated color temperature is approximately 3350 K, the first Lighting Preference Index is approximately 107, the second correlated color temperature is approximately 3000 K, and the second Lighting Preference Index is approximately 120.
17. The LED assembly of claim 1 , wherein the first correlated color temperature is approximately 3050 K, the first Lighting Preference Index is approximately 109, the second correlated color temperature is approximately 2755 K, and the second Lighting Preference Index is approximately 120.
18. The LED assembly of claim 1 , wherein the yellow-green phosphor comprises between 0.3 and 0.7 mg of yttrium aluminum garnet phosphor activated by cerium.
19. The LED assembly of claim 1 , wherein the red phosphor comprises between 1.0 and 2.0 mg of manganese-doped potassium fluoro-silicate phosphor.
20. The LED assembly of claim 1 , wherein the neodymium fluorine absorber combination comprises between 0.05 and 0.15 mg of neodymium fluoride.
21. An LED assembly, comprising:
an LED light source having a first light output with a characteristic spectrum; and
a yellow-green phosphor, red phosphor, and neodymium fluorine absorber combination deposited on a top surface of the LED light source, wherein the first light output passes through the yellow-green phosphor, red phosphor and neodymium fluorine absorber combination,
wherein the yellow-green phosphor, red phosphor, and neodymium fluorine absorber combination consists of a yellow-green phosphor, a red phosphor and a neodymium fluorine absorber and is configured to convert the first light output to a second light output having a Lighting Preference Index greater than 110 and a correlated color temperature between 4000 K-2700 K.