Light emitting diodes with enhanced thermal sinking and associated methods of operation
View Patent ↗Solid state lighting devices and associated methods of thermal sinking are described below. In one embodiment, a light emitting diode (LED) device includes a heat sink, an LED die thermally coupled to the heat sink, and a phosphor spaced apart from the LED die. The LED device also includes a heat conduction path in direct contact with both the phosphor and the heat sink. The heat conduction path is configured to conduct heat from the phosphor to the heat sink.
1. A light emitting diode (LED) device, comprising:
a substrate including a heat sink;
an LED die thermally coupled to the heat sink;
a phosphor spaced apart from the LED die;
a heat conduction path in direct contact with both the phosphor and the heat sink, the heat conduction path being configured to conduct heat from the phosphor to the heat sink; and
a plurality of vias positioned in the phosphor, wherein individual vias include a conductive material, and wherein the conductive material forms a portion of the heat conduction path.
2. The LED device of claim 1 wherein at least a portion of the heat conduction path is directly between the phosphor and the LED die.
3. The LED device of claim 1 wherein:
at least a portion of the heat conduction path is directly between the phosphor and the LED die; and
the LED die includes an electrical insulator proximate to the heat conduction path.
4. The LED device of claim 1 wherein:
the heat conduction path is a first heat conduction path; and
the LED device further includes a second heat conduction path in direct contact with the phosphor, the second heat conduction path being configured to conduct heat from the phosphor to the heat sink.
5. The LED device of claim 1 wherein:
the heat conduction path is a first heat conduction path;
the LED device further includes a second heat conduction path in direct contact with the phosphor, the second heat conduction path being configured to conduct heat from the phosphor to the heat sink; and
the first and second heat conduction paths are generally parallel to each other.
6. The LED device of claim 1 wherein:
the heat conduction path is a first heat conduction path; and
the LED device further includes a second heat conduction path and a third heat conduction path both in direct contact with the phosphor, the second heat conduction path being configured to conduct heat from the phosphor to the heat sink, and the third heat conduction path being configured to conduct heat from the phosphor to the first and/or second heat conduction paths.
7. The LED device of claim 1 wherein:
the heat conduction path is a first heat conduction path;
the LED device further includes a second heat conduction path and a third heat conduction path both in direct contact with the phosphor, the second heat conduction path being configured to conduct heat from the phosphor to the heat sink, and the third heat conduction path being configured to conduct heat from the phosphor to the first and/or second heat conduction paths;
the first and second heat conduction paths are generally parallel to each other; and
the third heat conduction path is generally perpendicular to the first and/or second heat conduction paths.
8. The LED device of claim 1 wherein:
the LED device further includes an insulating material between the heat conduction path and the LED die; and
the insulating material is configured to resist a heat flow from the LED die to the phosphor.
9. The LED device of claim 1 wherein:
the LED device further includes an insulating material between the conduction material and the LED die;
the insulating material is configured to resist a heat flow from the LED die to the phosphor via the insulating material; and
the heat conduction path is also configured to conduct at least a portion of the heat flow to the heat sink.
10. A light emitting diode (LED) device, comprising:
a substrate having a heat sink;
an LED die thermally coupled to the heat sink;
a phosphor spaced apart from the LED die; and
a heat conduction path in direct contact with both the phosphor and the heat sink, the heat conduction path being configured to conduct heat from the phosphor to the heat sink, wherein the heat conduction path includes a lateral portion across from a forward-facing surface of the LED die and at least one vertical portion extending from the lateral portion toward the heat sink such that the heat conduction path at least substantially covers the LED die; and
a plurality of vias positioned in the phosphor, wherein individual vias include a conductive material, and wherein the conductive material forms a portion of the heat conduction path.
11. The LED device of claim 10 wherein at least a portion of the heat conduction path is directly between the phosphor and the LED die.
12. The LED device of claim 10 wherein:
at least a portion of the heat conduction path is directly between the phosphor and the LED die; and
the LED die includes an electrical insulator proximate to the heat conduction path.
13. The LED device of claim 10 wherein:
the heat conduction path is a first heat conduction path; and
the LED device further includes a second heat conduction path in direct contact with the phosphor, the second heat conduction path being configured to conduct heat from the phosphor to the heat sink.
14. The LED device of claim 10 wherein:
the heat conduction path is a first heat conduction path;
the LED device further includes a second heat conduction path in direct contact with the phosphor, the second heat conduction path being configured to conduct heat from the phosphor to the heat sink; and
the first and second heat conduction paths are generally parallel to each other.
15. The LED device of claim 10 wherein:
the heat conduction path is a first heat conduction path; and
the LED device further includes a second heat conduction path and a third heat conduction path both in direct contact with the phosphor, the second heat conduction path being configured to conduct heat from the phosphor to the heat sink, and the third heat conduction path being configured to conduct heat from the phosphor to the first and/or second heat conduction paths.
16. The LED device of claim 10 wherein:
the heat conduction path is a first heat conduction path;
the LED device further includes a second heat conduction path and a third heat conduction path both in direct contact with the phosphor, the second heat conduction path being configured to conduct heat from the phosphor to the heat sink, and the third heat conduction path being configured to conduct heat from the phosphor to the first and/or second heat conduction paths;
the first and second heat conduction paths are generally parallel to each other; and
the third heat conduction path is generally perpendicular to the first and/or second heat conduction paths.
17. The LED device of claim 10 wherein:
the LED device further includes an insulating material between the heat conduction path and the LED die; and
the insulating material is configured to resist a heat flow from the LED die to the phosphor.
18. The LED device of claim 10 wherein at least a portion of the heat conduction path comprises a generally transparent material.
19. A light emitting diode (LED) device, comprising:
a substrate including a heat sink;
an LED die thermally coupled to the heat sink;
a converter material spaced apart from the LED die; and
a heat conduction path in direct contact with both the converter material and the heat sink, the heat conduction path being configured to conduct heat from the converter material to the heat sink, wherein the heat conduction path includes a lateral portion across from a forward-facing surface of the LED die and at least one vertical portion extending from the lateral portion toward the heat sink;
a plurality of vias positioned in the converter material, wherein individual vias include a conductive material, and wherein the conductive material forms a portion of the heat conduction path.
20. The LED device of claim 19 wherein:
the heat sink includes at least one of silicon (Si), gallium nitride (GaN), aluminum nitride (AlN), copper (Cu), aluminum (Al), tungsten (W), stainless steel (Fe), diamond (C), glass (SiO2), silicon carbide (SiC), and aluminum oxide (Al2O3);
the LED die includes an N-type gallium nitride (GaN) material, an indium gallium nitride (InGaN) material, and a P-type GaN material on one another in series;
the LED device further comprises an insulating material including at least one of a polyimide, a solvent-soluble thermoplastic polyimide, a ceramic material, and glass, the insulating material having a thermal conductivity less than about 0.15 W/(m·K);
the converter material includes at least one of cerium(III)-doped yttrium aluminum garnet (“YAG”), neodymium-doped YAG, neodymium-chromium double-doped YAG, erbium-doped YAG, ytterbium-doped YAG, neodymium-cerium double-doped YAG, holmium-chromium-thulium triple-doped YAG, thulium-doped YAG, chromium(IV)-doped YAG, dysprosium-doped YAG, samarium-doped YAG, and terbium-doped YAG, CaS:Eu, CaAlSiN3:Eu, Sr2Si5N8:Eu, SrS:Eu, Ba2Si5N8:Eu, Sr2SiO4:Eu, SrSi2N2O2:Eu, SrGa2S4:Eu, SrAl2O4:Eu, Ba2SiO4:Eu, Sr4Al14O25:Eu, SrSiAl2O3N:Eu, BaMgAl10O17:Eu, Sr2P2O7:Eu, BaSO4:Eu, and SrB4O7:Eu; and
the heat conduction path includes at least one of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), and zinc oxide (ZnO).