Quantum dot narrow-band downconverters for high efficiency LEDs
View Patent ↗The present disclosure is directed to LED components, methods and systems using such components, having light emitter devices with emissions tuned to meet CRI and LER goal values at a defined CCT. These emitter devices and methods may use a combination of light emitting diodes and quantum dots to tune the emission to meet these criteria. The quantum dots may incorporate additional features to protect the quantum dots from environmental conditions and improve heat dissipation, such as coatings and thermally conductive features.
1. A light emitting device, comprising:
a first light emitter on a support structure;
a plurality of narrow-band emitters, such that the first light emitter and the plurality of narrow-band emitters in combination provide an emission profile at a designated color correlated temperature (CCT) with a Color Rendering Index (CRI) of at least 80 and a lumens efficiency of radiation (LER) characteristic of at least 360, wherein said plurality of narrow-band emitters comprises at least two pluralities of quantum dots with different concentrations around said first light emitter, wherein said plurality of narrow-band emitters are within a barrier layer, said barrier layer on and conformal to said first light emitter, wherein part of said first light emitter is interposed between said barrier layer and said support structure; and
a broad-band layer comprising a plurality of broad-band emitters on said first light emitter, wherein said narrow-band emitters are closer to said first light emitter than said broad-band layer.
2. The device of claim 1 , in which the plurality of narrow-band emitters includes a third plurality of quantum dots.
3. The device of claim 1 , in which the plurality of narrow-band emitters includes a second light emitter.
4. The device of claim 1 , in which the CRI is >85 and the LER is >375.
5. The device of claim 1 , in which the narrow-band emitters comprise a Full Width Half Maximum (FWHM) of 20-44 nm.
6. The device of claim 1 , in which the designated CCT is 3,500 K and the plurality of narrow-band emitters are comprised of at least two pluralities of quantum dots, the first plurality of quantum dots comprising a peak wavelength of 525-535 nm and the second plurality of quantum dots comprising a peak wavelength of 585-595 nm.
7. The device of claim 6 , further comprising a third plurality of quantum dots comprising a peak wavelength of 605-625 nm.
8. The device of claim 6 , further comprising a second light emitter comprising a peak wavelength of 605-625 nm.
9. The device of claim 1 , in which the designated CCT is 3,000 K, further in which the plurality of narrow-band emitters are comprised of at least two pluralities of quantum dots and at least a third narrow-band emitter, the first plurality of quantum dots comprising a peak wavelength of 520-535 nm and the second plurality of quantum dots comprising a peak wavelength of 585-595 nm, the third narrow-band emitter comprising a peak wavelength of 618-622 nm.
10. The device of claim 1 , in which said plurality of broad-band emitters and said plurality of narrow-band emitters are in separate layers over the first light emitter.
11. The device of claim 1 , in which said plurality of broad-band emitters and said plurality of narrow-band emitters are mixed within at least one layer over the first light emitter.
12. The device of claim 1 , in which the light emitter is a light emitting diode (LED).
13. The device of claim 1 , in which at least a portion of the plurality of narrow-band emitters are tethered to said plurality of broad-band emitters.
14. The device of claim 13 , in which said plurality of broad-band emitters acts as a heat sink for at least a portion of the plurality of narrow-band emitters.
15. The device of claim 1 , in which the plurality of narrow-band emitters are comprised of narrow-band emitters of different peak wavelengths and each of said plurality of narrow-band emitters of different wavelengths are in separated multi-layers.
16. The device of claim 1 , in which the plurality of narrow-band emitters are comprised of narrow-band emitters of different peak wavelengths and each of said plurality of narrow-band emitters of different wavelengths are in at least one blended layer.
17. The device of claim 1 , in which the plurality of narrow-band emitters are comprised of narrow-band emitters of different peak wavelengths and said plurality of narrow-band emitters of different wavelengths are in separated multi-layers and at least one blended layer.
18. The device of claim 1 , in which the plurality of narrow-band emitters are comprised of quantum dots, and each of at least a portion of the quantum dots are coated by a barrier layer.
19. The device of claim 18 , in which the barrier layer is optically active.
20. The device of claim 18 , in which the barrier layer is thermally conductive.
21. The device of claim 18 , further comprising an encapsulant over the first light emitter and quantum dots, in which the barrier layer comprises a refractive index similar to the encapsulant material.
22. The device of claim 18 , in which the quantum dots are in contact with a heat sink.
23. The device of claim 22 , in which a surface of the first light emitter acts as the heat sink.
24. The device of claim 18 , in which a thermally conductive layer is in contact with at least a portion of the first light emitter and at least a portion of the quantum dots.
25. The device of claim 18 , in which a thermally conductive layer is over and in contact with at least a portion of the quantum dots.
26. The device of claim 25 , in which the thermally conductive layer comprises a volume at least 20 times larger than an active region of the quantum dots.
27. The device of claim 18 , in which at least a portion of the quantum dots are over at least a portion of a surface of the first light emitter.
28. The device of claim 27 , in which at least a portion of the quantum dots are over the first light emitter in varied densities.
29. The device of claim 1 , in which at least a portion of the plurality of narrow-band emitters receive and convert at least a portion of light emitted from the first light emitter.
30. A lighting emitting device, comprising:
a first light emitter;
at least three pluralities of narrow-band emitters, each emitting at a different peak wavelength range, such that the first light emitter and the at least three pluralities of narrow-band emitters in combination provide a spectral emission profile at a designated CCT with desired CRI and LER characteristics, in which the desired CRI is >80 and the desired LER is >360;
at least two of the at least three pluralities of narrow band emitters comprising pluralities of quantum dots, wherein said pluralities of quantum dots comprise different concentrations around said first light emitter;
wherein said at least three pluralities of narrow-band emitters are within a barrier layer, said barrier layer on and conformal to said first light emitter; and
a thermally conductive layer between said first light emitter and said barrier layer.
31. The device of claim 30 , in which the desired CRI is >85 and the desired LER is >375.
32. The device of claim 30 , in which the narrow-band emitters comprise a Full Width Half Maximum (FWHM) of 20-44 nm.
33. The device of claim 30 , in which a broad-band emitter acts as a heat sink for at least a portion of the pluralities of narrow-band emitters.
34. The device of claim 30 , in which the pluralities of narrow-band emitters are comprised of quantum dots, and each of at least a portion of the quantum dots are coated by a barrier layer.
35. The device of claim 34 , in which the quantum dots are in contact with a heat sink.
36. The device of claim 34 , in which said thermally conductive layer is over and in contact with at least a portion of the quantum dots.
37. A light emitting device, comprising:
a first light emitter;
a plurality of narrow-band emitters configured to reduce environmental damage to the plurality of narrow-band emitters, the plurality of narrow-band emitters also configured to include a heat dissipation feature, in which the plurality of narrow-band emitters are comprised of quantum dots, and each of at least a portion of the quantum dots are coated by a barrier layer, wherein said coating is on and conformal to a surface of said first light emitter and has a thickness of at least double the diameter of said quantum dots; and
a thermally conductive layer between said first light emitter and said barrier layer.
38. The device of claim 37 , in which the at least one light emitter and the plurality of narrow-band emitters in combination provide an emission profile at a designated color correlated temperature (CCT) with a Color Rendering Index (CRI) of at least 75 and a lumens efficiency of radiation (LER) characteristic of at least 350.
39. The device of claim 38 , in which the desired CRI is >80 and the desired LER is >360.
40. The device of claim 38 , in which the desired CRI is >85 and the desired LER is >375.
41. The device of claim 37 , in which the narrow-band emitters comprise a Full Width Half Maximum (FWHM) of 20-44 nm.
42. The device of claim 37 , in which a broad-band emitter acts as the heat dissipation feature for at least a portion of the plurality of narrow-band emitters.
43. The device of claim 37 , in which the plurality of narrow-band emitters are comprised of narrow-band emitters of different peak wavelengths.
44. The device of claim 37 , in which the heat dissipation feature is comprised of the barrier layer, such that the barrier layer is thermally conductive.
45. The device of claim 37 , in which the heat dissipation feature comprises a thermally conductive layer, the thermally conductive layer is over and in contact with at least a portion of the quantum dots.
46. The device of claim 45 , in which the thermally conductive layer comprises a volume at least thirty times larger than an active region of the quantum dots.
47. A method of tuning emitter package output, comprising:
providing a light emitter on a support structure;
providing a plurality of narrow-band emitters with a plurality of peak wavelength ranges, the plurality of peak wavelength ranges chosen such that the combination of the light emitter and the plurality of narrow-band emitters achieve a designated CCT at a desired CRI value of at least 80 and a desired LER value of at least 360;
wherein said plurality of narrow-band emitters comprises at least two pluralities of quantum dots, wherein said at least two pluralities of quantum dots comprise different concentrations around said light emitter;
wherein said plurality of narrow-band emitters are within a barrier layer, said barrier layer on and conformal to said light emitter such that part of said light emitter is interposed between said barrier layer and said support structure; and
providing a broad-band layer comprising a plurality of broad-band emitters on said light emitter, wherein said narrow-band emitters are closer to said light emitter than said broad-band layer.
48. The method of claim 47 , in which the desired CRI is >80 and the desired LER is >360.
49. The method of claim 47 , in which the desired CRI is >85 and the desired LER is >375.
50. The method of claim 47 , further comprising tethering at least a portion of the plurality of narrow-band emitters to a broad-band emitter.
51. The method of claim 47 , in which the plurality of narrow-band emitters are comprised of quantum dots, further comprising coating each of at least a portion of the quantum dots with a barrier layer.
52. The method of claim 47 , further comprising providing a heat dissipation feature in contact with the plurality of narrow-band emitters.
53. The method of claim 47 , further comprising disposing a thermally conductive layer over and in contact with at least a portion of the plurality of narrow-band emitters.
54. The method of claim 53 , in which providing the plurality of narrow-band emitters further comprises disposing at least a portion of the quantum dots over at least a portion of a surface of the light emitter.