Optoelectronic device with upconverting luminophoric medium

• US 8,297,061 B2
• Filed: 08/02/2007
• Issued: 10/30/2012
• Est. Priority Date: 08/02/2007
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Brandes, George R.
• Primary Examiner(s): Jones, Melvin
• Application Number:
  US11/832,785
• Publication Number:
  US 20090034201A1
• Time in Patent Office: 1,916 Days
• Field of Search: 62/31
• US Class Current: 62/3.1
• CPC Class Codes: C09K 11/7771 Oxysulfides
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/644 in intimate contact or integrated with parts of the device other than the semiconductor body
• CPC Class Codes: Y10T 29/4935 Heat exchanger or boiler making

Abstract

A microelectronic device that in operation generates or includes component(s) that generate heat, in which the device comprises a heat conversion medium that converts such heat into a light emission having a shorter wavelength than such heat, to thereby cool the device and dissipate the unwanted heat by such light output. The heat conversion medium can include an upconverting luminophoric material, e.g., an anti-Stokes phosphor or phosphor composition. The provision of such heat conversion medium enables thermal management of microelectronic devices, e.g., optoelectronic devices, to be achieved in an efficient manner, to prolong the operational service life of devices such as LEDs, laser diodes, etc. that are degraded in performance by excessive heat generation in their operation.

Claims

1. A microelectronic device comprising:

a heat-generating structure adapted to emit a visible light output and to generate heat energy, wherein the heat-generating structure includes at least one of a light emitting diode and a down-converting luminophoric medium; and

an upconverting luminophoric material that receives a portion of the heat energy and at least partially converts the portion of the heat energy to upconverted visible light in addition to the visible light emitted by the heat generating structure,

wherein the microelectronic device radiates the visible light output emitted by the heat-generating structure and the upconverted visible light.

2. The microelectronic device of claim 1, wherein the upconverting luminophoric material comprises an anti-Stokes phosphor.

3. The microelectronic device of claim 2, wherein the upconverting luminophoric material comprises a material of the formula L:

M, wherein L is yttrium oxide, yttrium fluoride, yttrium oxyfluoride, yttrium oxychloride, yttrium oxysulfide, or ytterbium oxychloride, and M is one or more of ytterbium, erbium, and thulium.

4. The microelectronic device of claim 2, wherein the upconverting luminophoric material comprises a material selected from the group consisting of Y₂O₂S:

Yb,Tm;

La₂O₂S;

Er,Yb;

Y₂O₂S;

Er,Yb;

YF₃;

Er,Yb;

Y₂O₃-YOF;

Er,Yb;

YOCl;

Er,Yb;

YbOCl;

Er.

5. The microelectronic device of claim 1, wherein the upconverting luminophoric material is arranged to receive the portion of the heat energy from the heat-generating structure at least in part by conductive heat transfer.

6. The microelectronic device of claim 1, wherein the upconverting luminophoric material is arranged to receive the portion of the heat energy from the heat-generating structure at least in part by radiative heat transfer.

7. The microelectronic device of claim 1, wherein the heat-generating structure comprises the light emitting diode.

8. The microelectronic device of claim 7, wherein the light emitting diode is formed of a III-V nitride material.

9. The microelectronic device of claim 8, wherein the down-converting luminophoric material is arranged to receive primary radiation from the light emitting diode and to responsively emit the visible light output.

10. The microelectronic device of claim 9, wherein the heat-generating structure comprises the down-converting luminophoric material.

11. The microelectronic device of claim 1, comprising an optoelectronic device.

12. The microelectronic device of claim 1, wherein the heat-generating structure comprises the light emitting diode die and the down-converting luminophoric material.

13. The microelectronic device of claim 1, wherein the upconverting luminophoric material is present in a layer containing same that is coated on at least a portion of said device.

14. The microelectronic device of claim 1, wherein the upconverting luminophoric material is present in a layer containing same that is coated on at least a portion of said heat generating structure.

15. A microelectronic device generating a visible light output and heat energy in operation of the device, and an upconverting material arranged to receive a portion of the heat energy and to at least partially convert the portion of the heat energy into upconverted visible light in addition to the visible light emitted by the microelectronic device.

16. The microelectronic device of claim 15, comprising a heat-generating structure including a light emitting diode or a laser diode, wherein the heat-generating structure generates the visible light output and the heat energy.

40. The microelectronic device of claim 15, comprising a heat-generating structure including (i) one of a light emitting diode or a laser diode;

and (ii) a down-converting luminophoric material, wherein the heat-generating structure generates the visible light output and the heat energy.

17. A microelectronic device comprising:

a device configured to generate primary radiation and to radiate heat energy as a result of the generation of the primary radiation, wherein the device includes a down-converting material configured to receive a portion of the primary radiation and to partially down-convert the portion of the primary radiation to a first visible light output and to radiate at least a part of the heat energy; and

an upconverting material configured to receive at least a portion of the heat energy radiated and to partially upconvert the portion of the heat energy into a second visible light output that is emitted by the microelectronic device in addition to the first visible light output.

18. The microelectronic device of claim 17, wherein the upconverting material comprises an anti-Stokes phosphor, and the down-converting material comprises a Stokes phosphor.

19. A method of thermally managing an optoelectronic device configured to emit a visible light output and to generate heat, comprising absorbing a portion of the heat with an upconverting luminophoric material that in exposure to the portion of the heat at least partially converts the portion of the heat to a heat-dissipative visible light output that is radiated together with the emitted visible light output.

20. The method of claim 19, wherein the upconverting luminophoric material comprises an anti-Stokes phosphor.

21. The method of claim 19, wherein the upconverting luminophoric material comprises a material of the formula L:

M, wherein L is yttrium oxide, yttrium fluoride, yttrium oxyfluoride, yttrium oxychloride, yttrium oxysulfide, or ytterbium oxychloride, and M is one or more of ytterbium, erbium, and thulium.

22. The method of claim 19, wherein the upconverting luminophoric material comprises a material selected from the group consisting of Y₂O₂S:

Yb,Tm;

La₂O₂S;

Er,Yb;

Y₂O₂S;

Er,Yb;

YF₃;

Er,Yb;

Y₂O₃-YOF;

Er,Yb;

YOCl;

Er,Yb;

YbOCl;

Er.

23. The method of claim 19, wherein the upconverting luminophoric material is arranged to receive the portion of the heat from a heat-generating structure of the optoelectronic device by conductive heat transfer or by radiative heat transfer.

24. The method of claim 19, wherein the optoelectronic device includes a light emitting diode and a down-converting luminophoric material arranged to receive primary radiation from the light emitting diode and to responsively emit the visible light output.

25. The method of claim 24, wherein the heat is generated in the down-converting luminophoric material.

26. A method of thermally managing an optoelectronic device generating a visible light output and heat energy in operation of the optoelectronic device, comprising reducing the heat energy of the device by thermally coupling an upconverting material with the optoelectronic device, wherein the upconverting material is configured to convert a portion of the heat energy into a heat-dissipative visible light output that is radiated together with the visible light output.

27. The method of claim 26, wherein the optoelectronic device comprises a light emitting diode or a laser diode.

41. The method of claim 26, wherein the optoelectronic device comprises (i) one of a light emitting diode or a laser diode;

and (ii) a down-converting luminophoric material.

28. A method of thermally managing an optoelectronic device, comprising incorporating an upconverting material and a down-converting material therein, wherein the down-converting material is configured to receive a portion of a primary radiation from the optoelectronic device and to partially convert the portion of the primary radiation into visible light energy and heat energy, and wherein the upconverting material is configured to receive a portion of the heat energy and to partially convert the portion of the heat energy into a heat-dissipative visible light output that is radiated together with the visible light energy converted by the down-converting material.

29. The method of claim 28, wherein the upconverting material comprises an anti-Stokes phosphor and the down-converting material comprises a Stokes phosphor.

30. A method of fabricating a microelectronic device, comprising incorporating in said microelectronic device multiple upconverting and/or down-converting elements that are responsive to energy emitted by any of light emitting regions of the microelectronic device to produce a visible light output as part of a predetermined visible light output spectrum for the microelectronic device, wherein the multiple upconverting and/or down-converting elements include at least one upconverting element configured to convert at least a portion of heat energy generated by the microelectronic device into a heat-dissipative visible light output that is radiated with the visible light output of the microelectronic device as part of the predetermined light output spectrum for the microelectronic device.

31. A microelectronic device that in operation generates or includes component(s) that generate visible light and heat, the device comprising a heat conversion medium, including an emissive conversion material that converts at least a portion of said heat into a heat-dissipative visible light emission having a shorter wavelength than said heat radiation, and wherein the heat-dissipative visible light emission is radiated together with the visible light generated.

32. The microelectronic device of claim 31, wherein said heat-dissipative visible light emission is effective to cool the microelectronic device.

33. The microelectronic device of claim 31, wherein said heat-dissipative visible light emission is effective to cool the microelectronic device to a greater extent, in relation to a corresponding microelectronic device lacking said heat conversion medium wherein said heat is dissipated by radiative and conductive cooling of said microelectronic device.

34. The microelectronic device of claim 31, wherein heat is transferred from said microelectronic device or component(s) thereof to said heat conversion medium by at least one of conduction and radiation.

35. The microelectronic device of claim 31, wherein said heat conversion medium comprises multiple phosphor materials including an anti-Stokes phosphor.

36. The microelectronic device of claim 31, wherein said component(s) that generate heat comprise at least one of a down-converting luminophoric material and a light emitting diode.

37. A microelectronic device that in operation generates visible light and generates heat or includes component(s) that generate said heat, the microelectronic device comprising a heat conversion medium that converts said heat to a heat-dissipative visible light emission that is radiated by the microelectronic device together with the generated visible light.

38. A microelectronic device that in operation emits visible light and generates heat energy or includes component(s) that emit said visible light and generate the heat energy, in which the device comprises an upconverting material that receives at least a portion of the heat energy and partially upconverts at least a portion of the heat energy into upconverted visible light that is radiated together with the emitted visible light.

39. A method of thermally managing a microelectronic device configured to emit visible light, comprising incorporating therein an upconverting material that produces upconverted visible light in response to heat energy from at least one of an external light source and/or energy from an active region of the microelectronic device, and converts the heat energy into heat-dissipative visible light that is radiated together with the emitted visible light.