Full spectrum phosphor blends for white light generation with LED chips
View Patent ↗A light emitting device including a phosphor blend including four or more phosphors emitting within a specific spectral range to optimize the color rendering index (CRI) for a given color coordinated temperature (CCT). The blend will include at least four phosphors selected from the following: a blue phosphor having an emission peak at 400-500 nm, a green phosphor having an emission peak at 500-575 nm, an orange phosphor having an emission peak from 575-615 nm, and a deep red phosphor having an emission peak at 615-680 nm. The preferred blends are used to make light sources with general CRI values (R a ) greater than 95 at CCT's from about 2500 to 8000 K.
1. A lighting apparatus for emitting white light comprising: a semiconductor light source emitting radiation at from about 250 nm to about 450 nm; and a phosphor material radiationally coupled to the light source, the phosphor material comprising a red emitting phosphor having a peak emission between about 615 and 680 nm, an orange emitting phosphor having a peak emission between about 575 and 615 nm, a green emitting phosphor having a peak emission between about 500 and 575 nm, a blue emitting phosphor having a peak emission between about 400 and 500 nm, and one or more additional gap filling phosphors, wherein said lighting apparatus has a full spectrum between 400 and 700 nm.
2. The lighting apparatus of claim 1 , wherein the light source comprises one of an LED and an organic emissive structure.
3. The lighting apparatus of claim 1 , further comprising an encapsulant surrounding the light source.
4. The lighting apparatus of claim 3 , wherein the phosphor material is dispersed in the encapsulant.
5. The lighting apparatus of claim 1 , further comprising a reflector cup.
6. The lighting apparatus of claim 1 , further including a pigment, filter or other absorber capable of absorbing radiation generated between 250 nm and 450 nm.
7. The lighting apparatus of claim 1 , wherein said red phosphor comprises at least one of (Mg, Ca, Sr, Ba, Zn)4Si2O8:Eu2+, Mn2+; and 3.5MgO*0.5MgF2*GeO2:Mn4+.
8. The lighting apparatus of claim 1 , wherein said green phosphor comprises at least one of (Ca, Sr, Ba) Al204:Eu2+; and (Ca, Sr, Ba, Zn) 2SiO4:Eu2+.
9. The lighting apparatus of claim 1 , wherein said blue phosphor comprises at least one of (Ca, Sr, Ba) 5 (PO4) 3 (F, Cl, Br, OH):Eu2+, and (Ca, Sr, Ba) MgxAlyO(1+x+1.5y):Eu2+, wherein x is an integer between about 1 and 5 and y is an integer between about 5 and 25.
10. The lighting apparatus of claim 1 , wherein said orange phosphor comprises at least one of (Mg, Ca, Sr, Ba, Zn)2P2O7:Eu2+, Mn2+ and (Ca, Sr, Ba) 5 (PO4) 3 (F, Cl, Br, OH):Eu2+, Mn2+.
11. The lighting apparatus of claim 1 , wherein said gap filling phosphors are selected from one or more of Sr4Al14O25:Eu2+; (Mg, Ca, Sr, Ba, Zn) 4Si208:Eu2+; (Ba, Ca, Sr) 2MgAl, 6027:Eu2+, Mn2+, and mixtures thereof.
12. The lighting apparatus of claim 1 , wherein said blue phosphor is present in a spectral weight of from about 1 to 45%, said green phosphor is present in a spectral weight of from about 15 to 60%, said red phosphor is present in a spectral weight of from about 5 to 55%, and said orange phosphor is present in a spectral weight of from about 20 to 75%.
13. The lighting apparatus of claim 1 , wherein said lighting apparatus has a general CRI (Ra) greater than 90.
14. The lighting apparatus of claim 1 , wherein said lighting apparatus has a mean CRI (R1-R14) greater than 90.
15. The lighting apparatus of claim 1 , herein said lighting apparatus has a CRI (Rg) greater than 80.
16. The lighting apparatus of claim 1 , wherein a color point of said phosphor material lies on or substantially on the black body locus of the CIE chromaticity diagram.
17. The lighting apparatus of claim 1 , wherein said lighting apparatus has a CCT of from about 2500 to 8000 K.