LED lamp incorporating remote phosphor and diffuser with heat dissipation features
LED lamps or bulbs are disclosed that comprise a light source, a heat sink structure and a remote phosphor carrier having at least one conversion material. The phosphor carrier can be remote to the light sources and mounted to the heat sink. The phosphor carrier can have a three-dimensional shape and comprise a thermally conductive transparent material and a phosphor layer, with an LED based light source mounted to the heat sink such that light passes through the phosphor carrier. The phosphor carrier converts at least some of the LED light, with some embodiments emitting a white light combination of LED and phosphor light. The phosphors in the phosphor carriers can operate at a lower temperature to have greater phosphor conversion efficiency and reduced heat related damage. The lamps or bulbs can also comprise a diffuser over the phosphor carrier to distribute light and conceal the phosphor carrier.
1. A phosphor carrier for an LED lamp, comprising:
a thermally conductive carrier layer;
a phosphor layer on said carrier layer such that light emitted from a LED lamp passes through said phosphor layer and is converted by said phosphor layer, wherein a full width of a surface of said phosphor layer is shaped to provide varying surface angles; and
a heat sink which defines an optical cavity, wherein said thermally conductive carrier layer and said LED lamp are in thermal contact with said heat sink;
wherein heat from said phosphor layer passes into and dissipates from said carrier layer and said heat sink, wherein said heat sink comprises separate thermal dissipation paths for said carrier layer and said LED lamp, and wherein said separate thermal dissipation paths are substantially thermally isolated from one another.
2. The phosphor carrier of claim 1 , wherein said carrier layer has thermal conductivity of at least 0.5 W/m-k.
3. The phosphor carrier of claim 1 , wherein said carrier layer has a thickness in the range of 0.1 to 10 mm.
4. The phosphor carrier of claim 1 , wherein said carrier layer is shaped to enhance light extraction.
5. The phosphor carrier of claim 1 , further comprising scattering particles to disperse light emitted from said LED lamp.
6. The phosphor carrier of claim 5 , wherein said scattering particles comprise a layer of scattering particles on said carrier layer.
7. The phosphor carrier of claim 5 , wherein said scattering particles are dispersed in said carrier layer.
8. The phosphor carrier of claim 1 , wherein said phosphor layer comprises multiple phosphors.
9. The phosphor carrier of claim 8 , wherein said multiple phosphors absorb LED light and emit yellow, red and/or green light.
10. The phosphor carrier of claim 1 , wherein said phosphor layer is remote from an LED.
11. The phosphor carrier of claim 1 , wherein said carrier layer is planar.
12. The phosphor carrier of claim 1 , wherein said carrier layer is non-planar.
13. A phosphor carrier for an LED lamp, comprising:
a thermally conductive carrier layer; and
a phosphor layer on said carrier layer and arranged such that light emitted from an LED light source passes through said phosphor layer and is converted by said phosphor layer;
wherein said carrier layer dissipates heat generated from said phosphor layer through a thermal path that is thermally decoupled from a thermal path of said LED light source, and
wherein the full width of a surface of said phosphor layer is roughened; and
wherein said phosphor layer covers less than all of a surface of said carrier layer and at least a portion of said uncovered carrier layer surface is in thermal contact with a heat sink.
14. The phosphor carrier of claim 13 , further comprising a scattering particle layer.
15. The phosphor carrier of claim 14 , wherein said scattering particle layer is on said phosphor layer.
16. The phosphor carrier of claim 14 , wherein said scattering particle layer is on said carrier layer.
17. The phosphor carrier of claim 13 , wherein said carrier layer is transparent.
18. The phosphor carrier of claim 13 , wherein said phosphor layer is arranged such that LED light passes through said phosphor layer before said carrier layer.
19. The phosphor carrier of claim 13 , wherein said carrier layer and phosphor layer comprise the same material.
20. The phosphor carrier of claim 13 , wherein said phosphor layer covers all of a surface of said carrier layer.
21. The phosphor carrier of claim 13 , wherein said phosphor layer comprises more than one phosphor.
22. The phosphor carrier of claim 13 , wherein said heat sink defines an optical cavity, wherein said LED light source is within said optical cavity, said thermally conductive carrier layer being in thermal contact with said heat sink.
23. A light emitting diode (LED) lamp, comprising:
a thermally conductive platform;
an LED light source on said platform defining a first thermal path from said light source into said platform;
a phosphor carrier arranged so the light from said LED light source passes through said phosphor carrier, said phosphor carrier comprising:
a thermally conductive carrier layer;
a phosphor layer on a surface of said carrier layer and arranged such that light emitted from said LED light source passes through said phosphor layer and is converted, and wherein heat from said phosphor layer passes into and dissipates from said carrier layer, wherein said phosphor layer covers less than all of said surface of said carrier layer and at least a portion of said uncovered carrier layer surface is in thermal contact with a heat sink; and
a heat sink in thermal contact with said phosphor carrier layer and defining a second thermal path that is thermally decoupled from said first thermal path.
24. The LED lamp of claim 23 , wherein said carrier layer has thermal conductivity of at least 0.5 W/m-k.
25. The LED lamp of claim 23 , wherein said phosphor layer and/or said carrier layer is shaped to enhance light extraction.
26. The LED lamp of claim 23 , further comprising scattering particles to disperse light emitted from said LED light source.
27. The LED lamp of claim 23 , wherein said heat sink defines an optical cavity, said LED light source being within said optical cavity, said thermally conductive carrier layer being in thermal contact with said heat sink.
28. A method for forming a phosphor carrier for an LED lamp, comprising:
forming a thermally conductive carrier layer;
forming a phosphor layer on said carrier layer such that light emitted from said LED lamp passes through said phosphor layer and is converted by said phosphor layer, the full width of a surface of said phosphor layer being shaped to provide varying surface angles;
providing a heat sink such that said thermally conductive carrier layer and said LED lamp are in thermal contact with said heat sink wherein said heat sink defines an optical cavity and comprises separate thermal dissipation paths for said carrier layer and said LED lamp, and wherein said separate thermal dissipation paths are substantially thermally isolated from one another such that heat from said phosphor layer passes into and dissipates from said carrier layer and said heat sink via one of the separate thermal dissipation paths.
29. The method of claim 28 , wherein said phosphor layer is formed by one of the methods from the group spray coating, spin coating, sputtering, printing, powder coating, electrophoretic deposition (EPD) and electrostatic deposition.
30. The method of claim 28 , wherein said phosphor layer comprises a phosphor in a binder.
31. The method of claim 30 , further comprising curing said binder.
32. The method of claim 30 , further comprising heating said carrier layer, with heat from said carrier layer curing said binder.
33. The method of claim 32 , wherein said phosphor layer further comprises a solvent, the heat from said carrier layer evaporates said solvent and cures said binder.
34. The method of claim 28 , further comprising reducing the thickness of said phosphor layer.
35. The method of claim 34 , wherein reducing the thickness of said phosphor layer comprises grinding.