LED based device with wide color gamut
The invention provides a lighting unit comprising a source of blue light, a source of green light, a first source of red light comprising a first red luminescent material, configured to provide red light with a broad band spectral light distribution, and a second source of red light comprising a second red luminescent material, configured to provide red light with a spectral light distribution comprising one or more red emission lines. Especially, the first red luminescent material comprises (Mg,Ca,Sr)AlSiN 3 :Eu and/or (Ba,Sr,Ca) 2 Si 5-x Al x O x N 8-x :Eu, and the second red luminescent material comprises K 2 SiF 6 :Mn.
1. A device comprising:
a light emitting diode;
a green light source;
a first red luminescent material to provide red light with a broad band spectral light distribution, the first red luminescent material disposed in a path of light emitted by the light emitting diode; and
a second red luminescent material to provide red light with a spectral light distribution comprising one or more red emission lines, the second red luminescent material disposed in a path of light emitted by the light emitting diode, wherein the second red luminescent material provides red light with a spectral light distribution comprising one or more red emission lines having a centroid emission wavelength ≥610 nm and with one or more red emission lines having a full width half maximum (FWHM) of ≤6 nm.
2. The device of claim 1 , wherein the first and the second red luminescent materials are mixed with resin and disposed on top of the light emitting diode.
3. The device of claim 1 , wherein the light emitting diode is a first light emitting diode emitting blue light, and the green light source is a second light emitting diode emitting green light.
4. The device of claim 3 , further comprising a light transmissive window disposed in a path of light emitted by the first and the second light emitting diodes.
5. The device of claim 4 , wherein the first and the second light emitting diodes are disposed in a chamber.
6. The device of claim 3 , further comprising RGB filters disposed in a path of light emitted by the first and the second light emitting diodes.
7. The device of claim 1 , wherein the first and the second red luminescent materials are arranged at a non-zero distance from the light emitting diode.
8. The device of claim 1 , wherein the non-zero distance is between 0.1 and 100 mm.
9. The device of claim 1 , wherein the first and the second red luminescent materials are embedded in silicone on the light emitting diode.
10. The device of claim 1 , wherein the green light source comprises a green luminescent material disposed in a path of light emitted by the light emitting diode.
11. The device of claim 1 , wherein the light emitting diode emits UV light, the device further comprising a blue luminescent material.
12. The device of claim 1 , wherein the first red luminescent material provides red light with a broad band spectral light distribution having a centroid emission wavelength ≥590 nm and with a full width half maximum (FWHM) of ≥70 nm.
13. The device of claim 1 , wherein the first red luminescent material is selected from (Mg,Ca,Sr,Ba)AlSiN 3 :Eu and (Ba,Sr,Ca) 2 Si 5-x Al x O x N 8-x Eu, wherein 0≤x≤4.
14. The device of claim 1 , wherein the second red luminescent material is selected from M 2 AX 6 doped with tetravalent manganese, wherein M comprises monovalent cations, selected from Li, Na, K, Rb, Cs, and NH 4 , wherein A comprises a tetravalent cation selected from Si, Ti, Ge, Sn, and Zr, and wherein X comprises a monovalent anion selected from F, Cl, Br and I, but at least comprising F.
15. The device of claim 1 , wherein the second red luminescent material comprises core-shell quantum dots.
16. The device of claim 1 , wherein the light emitting diode is a first light emitting diode that emits blue light, wherein the green light source comprises a second light emitting diode with centroid emission wavelength in the range of 510-540 nm, wherein the first red luminescent material is selected from (Mg,Ca,Sr,Ba)AlSiN 3 :Eu and (Ba,Sr,Ca) 2 Si 5-x Al x O x N 8-x :Eu, wherein x=0≤x≤4, and wherein the second red luminescent material comprises core-shell quantum dots.
17. The device of claim 1 , wherein:
the green light source comprises a green luminescent material selected from a divalent europium containing oxynitride, a divalent europium containing thiogallate, a trivalent cerium containing nitride, a trivalent cerium containing oxynitride, and a trivalent cerium containing garnet;
the first red luminescent material is selected from (Mg,Ca,Sr,Ba)AlSiN 3 :Eu and (Ba,Sr,Ca) 2 Si 5-x Al x O x N 8-x :Eu, wherein 0≤x≤4; and
the second red luminescent material is selected from M 2 AX 6 doped with tetravalent manganese, wherein M comprises monovalent cations, selected from Li, Na, K, Rb, Cs, and NH 4 , wherein A comprises a tetravalent cation selected from Si, Ti, Ge, Sn, and Zr, and wherein X comprises a monovalent anion selected from F, Cl, Br and I, but at least comprising F.
18. The device of claim 17 , wherein the green luminescent material and the first and the second red luminescent materials are disposed in a light converter arranged on the light emitting diode.
19. The device of claim 1 , wherein the first and the second red luminescent materials are different materials.