Reflective nanofiber lighting devices

• US 8,864,341 B2
• Filed: 12/11/2013
• Issued: 10/21/2014
• Est. Priority Date: 07/23/2012
• Status: Expired due to Fees

• Current Assignee: Research Triangle Institute
• Original Assignee: Research Triangle Institute
• Inventors: Davis, James Lynn, Michael, Larry Charles, Mills, Karmann C.
• Primary Examiner(s): Mai, Anh
• Assistant Examiner(s): Snyder, Zachary J
• Application Number:
  US14/103,110
• Publication Number:
  US 20140160723A1
• Time in Patent Office: 314 Days
• Field of Search: 362/296.01, 362/296.02, 362/341
• US Class Current: 362/296.02
• CPC Class Codes: F21V 13/08 the elements being filters or photoluminescent elements and reflectors
• CPC Class Codes: F21V 7/0008 providing for indirect lighting
• CPC Class Codes: F21V 7/043 with cylindrical surface
• CPC Class Codes: F21V 7/10 Construction
• CPC Class Codes: F21V 7/26 the material comprising photoluminescent substances
• CPC Class Codes: F21V 7/28 characterised by coatings
• CPC Class Codes: F21V 9/32 characterised by the arrangement of the photoluminescent material
• CPC Class Codes: F21V 9/38 Combination of two or more photoluminescent elements of different materials

Abstract

A fiber-based reflective lighting device. The lighting device includes a source configured to generate a primary light, a substrate including a mat of reflective nanofibers, and a light exit configured to emanate the reflected light. The fibers have an average fiber diameter AFD less than 500 nm which diffusively reflects visible light upon illumination with at least the primary light. The mat has a basis weight less than 40 gram per square meter (gsm) and a reflectance greater than 80%.

Claims

1. A fiber-based reflective lighting device comprising:

a source configured to generate a primary light;

a substrate including a mat of reflective nanofibers, the fibers having an average fiber diameter AFD less than 500 nm which diffusively reflects visible light upon illumination with at least the primary light;

said mat having a basis weight less than 40 gram per square meter (gsm) and a reflectance greater than 80%; and

a light exit configured to emanate the reflected light.

2. The device of claim 1, where said basis weight of the mat is less than 30 gsm.

3. The device of claim 1, where said basis weight of the mat is less than 20 gsm.

4. The device of claim 1, where said reflectance of the mat greater than 90%.

5. The device of claim 1, where said reflectance of the mat greater than 95%.

6. The device of claim 1, further comprising:

a luminescent sheet having light stimulatable particles configured to emit secondary light upon receiving the primary light.

7. The device of claim 6, wherein the mat comprises:

at least one of a planar or a curved reflector surface disposed behind or in front of the luminescent sheet.

8. The device of claim 7, wherein the reflector surface comprises spherical or cylindrical reflector surfaces.

9. The device of claim 6, wherein the source comprises at least two light sources disposed to illuminate the luminescent sheet.

10. The device of claim 1, where said mat has an average interfiber spacing, as measured by mean flow pore diameter, that is less than 80% of the maximum interfiber spacing, as measured by bubble point.

11. The device of claim 1, where said mat has an average interfiber spacing, as measured by mean flow pore diameter, that is less than 90% of the maximum interfiber spacing, as measured by bubble point.

12. The device of claim 1, wherein

AFD ranges from 150 to 300 nm;

Mean Flow Pore Diameter ranges from 250-600 nm;

Bubble Point Pore Diameter ranges from 450-1,000 nm;

Basis Weight ranges from 5-40 gsm; and

Reflectance @550 nm ranges from 0.85 to 0.999.

13. The device of claim 1, wherein

AFD ranges from 150-250 nm;

Mean Flow Pore Diameter ranges from 150-300 nm; and

Bubble Point Pore Diameter ranges from 200-400 nm.

14. The device of claim 1, wherein the reflective fibers include at least one of Al, Au, Ag, TiO₂, ZnO, BaSO₄, and Zn.

15. The device of claim 1, wherein the mat comprises a reflective material having a reflectance greater than 0.9.

16. The device of claim 1, wherein the fibers comprise polymer fibers.

17. The device of claim 16, wherein the polymer nanofibers comprise at least one of poly(dimethyl siloxane), poly(vinylidene fluoride), poly(ethylene oxide), poly(methyl methacrylate), poly(propylene), poly(vinyl alcohol), poly(ethylene), nylon 6, nylon 6-12, nylon 6-6, polycarbonate, polyamide, polysulfone, polybutylene terephthlate, and polyethylene terephthlate, or combinations thereof.

18. The device of claim 1, wherein the source configured to generate said primary light comprises a light emitting diode.

19. The device of claim 18, where the light emitting diode emits visible light.

20. The device of claim 1, wherein the source configured to generate said primary light comprises a fluorescent lamp.

21. The device of claim 1, further comprising:

stimulatable particles disposed at least on a surface of the reflective nanofiber mat or a surface of nanofibers separate from the reflective nanofiber mat.

22. The device of claim 21, wherein the stimulatable particles comprise at least one of quantum dots and phosphors.

23. The device of claim 22, wherein the quantum dots comprise at least one of silicon, germanium, indium phosphide, indium gallium phosphide, indium phosphide, cadmium sulfide, cadmium selenide, lead sulfide, copper oxide, copper selenide, gallium phosphide, mercury sulfide, mercury selenide, zirconium oxide, zinc oxide, zinc sulfide, zinc selenide, zinc silicate, titanium sulfide, titanium oxide, and tin oxide.

24. The device of claim 22, wherein the phosphors comprise at least one of a rare-earth doped metal oxide including Y₂O₃:

Tb, Y₂O₃;

Eu³⁺, Lu₂O₃;

Eu³⁺, CaTiO₃;

Pr³⁺, CaO;

Er³⁺, (GdZn)O;

Eu³⁺, Sr₄Al₁₄O₂₅;

Eu³⁺, GdMgB₃O₁₀;

Ce³⁺;

Tb³⁺, CeMgAl₁1O₁₉;

Ce³⁺;

Tb³⁺, Y₂O₃;

Eu³⁺, a rare-earth doped yttrium aluminum garnet (YAG) including YAG;

Ce³⁺, a rare-earth doped zirconium oxide including ZrO₂;

Sm³⁺ and ZrO₂;

Er³⁺, rare earth doped vanadates and phosphates including (YVO₄;

Eu) and (La,Ce,Tb)PO₄, doped materials having a host matrix including one Gd₂O₃, GdO₂S, PbO, ZnO, ZnS, and ZnSe and including one of a dopant of Eu, Tb, Tm and Mn, metal-doped forms of zinc sulfide and zinc selenide including ZnS;

Mn²⁺ and ZnS;

Cu⁺, Zn_0.25Cd_0.75S;

AgCl, metal sulfides including CaS;

Eu²⁺, SrGa₂S₄;

Eu and Ca_wSr_xGa_y(S,Se)_z;

Eu, doped silicates, and metal silicates including Ca₃(Sc,Mg)₂Si₃O₁₂;

Ce and (Ba,Sr)₂SiO₄;

Eu.

25. The device of claim 22, wherein the phosphors comprise at least one of rare-Earth doped YAG, rare-Earth doped ZnS, rare-Earth doped SrGa₂S₄, rare-Earth doped ZnSe, rare-Earth doped silicates, and sulfoselenides.

26. The device of claim 22, wherein the phosphor comprises a nano-phosphor.

27. The device of claim 1, wherein the mat reflects at least 90% of all visible light from 400 nm to 720 nm.

28. The device of claim 1, wherein the mat reflects at least 95% of all visible light from 400 nm to 720 nm.

29. The device of claim 1, wherein the mat reflects at least 97% of all visible light from 420 nm to 720 nm.

30. A lighting device insert comprising:

a substrate including a nanofiber mat of reflective fibers, the fibers having an average fiber diameter less than 500 nm which diffusively reflects visible light upon illumination with at least a primary light;

said nanofiber mat having an average interfiber spacing, as determined by mean flow pore diameter, that is less than 80% of the maximum interfiber spacing, as determined by the bubble point;

said nanofiber mat configured to diffusively reflect at least 80% of incident light.

31. A method for diffusively reflecting visible light, comprising:

directing a primary light beam to a mat of reflective nanofibers;

diffusively reflecting visible light from the mat of reflective nanofibers, said nanofibers having an average fiber diameter less than 500 nm and the mat has an average interfiber spacing, as determined by mean flow pore diameter, that is less than 80% of the maximum interfiber spacing, as determined by the bubble point.