Reflective nanofiber lighting devices

• US 9,228,716 B2
• Filed: 06/01/2012
• Issued: 01/05/2016
• Est. Priority Date: 04/08/2004
• Status: Active Grant

• Current Assignee: Research Triangle Institute
• Original Assignee: Research Triangle Institute
• Inventors: Davis, James Lynn, Guzan, Kimberly A., Mills, Karmann C., Lamvik, Michael K., Bittle, James F., Haines, Laura
• Primary Examiner(s): DZIERZYNSKI, EVAN P
• Application Number:
  US14/123,248
• Publication Number:
  US 20140119026A1
• Time in Patent Office: 1,313 Days
• Field of Search: 362/296.02
• US Class Current: 1/1
• CPC Class Codes: D06M 11/00 Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising D06M10/00 takes precedence
• CPC Class Codes: D06M 13/00 Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds D06M10/00, D06M14/00 take precedence; treatment with complexes of organic amines with inorganic substances D06M11/59; Such treatment combined with mechanical treatment
• CPC Class Codes: D06M 15/00 Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment D06M10/00, D06M14/00 take precedence; treatment with inorganic polyphosphates D06M11/72
• CPC Class Codes: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• CPC Class Codes: F21V 7/0008 providing for indirect lighting
• CPC Class Codes: F21V 7/24 characterised by the material
• CPC Class Codes: F21V 7/28 characterised by coatings
• CPC Class Codes: F21V 9/30 Elements containing photoluminescent material distinct from or spaced from the light source shades F21V1/17; globes, bowls or cover glasses F21V3/08, F21V3/12; refractors F21V5/10; reflectors F21V7/26, F21V7/30; elements with provision for controlling the spectral properties or intensity F21V9/40
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

A fiber-based reflective lighting device and a housed lighting device. The fiber-based reflective lighting device which includes a source configured to generate a primary light, and a substrate having a nanocomposite mat of reflective fibers having a diameter less than 1,000 nm which diffusively reflects light upon illumination with at least the primary light. The nanocomposite mat includes a reflectance-enhancing coating conformally disposed around an outer surface of the fibers, having a refractive index different from the reflective fibers, and which increases a reflectance of the substrate in the visible spectrum. The lighting device includes a light exit configured to emanate the reflected light. The housed lighting device includes a housing, a source configured to generate primary light and direct the primary light into the housing, the reflective nanocomposite mat of reflective fibers, and a light exit in the housing configured to emanate the reflected light from the housing.

Claims

1. A fiber-based reflective lighting device comprising:

a source configured to generate a primary light;

a substrate having a nanocomposite mat of reflective fibers having diameters less than 1,000 nm which diffusively reflects visible light upon illumination with at least the primary light;

said nanocomposite mat including a reflectance-enhancing coating conformally disposed around an outer surface of the fibers, having a refractive index different from the reflective fibers, and which increases a reflectance of the substrate in the visible spectrum; and

a light exit configured to emanate the reflected light.

2. The device of claim 1, wherein

the coating comprises bridge elements connected between the reflective fibers and forming light scattering sites between adjacent fibers, or

the coating comprises nodules or segments on the reflective fibers forming light scattering sites on the fibers.

3. The device of claim 1, wherein the reflectance-enhancing coating comprises an optically clear coating.

4. The device of claim 1, wherein the reflectance-enhancing coating comprises at least one of parylene coatings, perfluorosilane coatings, vacuum plasma coatings, atomic layer deposition coatings, perfluorinated coatings, phosphonate dip coatings, and silicone coatings, or mixtures thereof.

5. The device of claim 1, wherein the reflectance-enhancing coating comprises a coating having a thickness of at least one of less than 50 nm, less than 200 nm, less than 2000 nm, or less than 5,000 nm.

6. The device of claim 1, wherein a difference in refractive indices of the reflective fibers and the coating is less than 0.20 or less than 0.12.

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

8. The device of claim 1, wherein the mat of reflective fibers comprises a reflective material having a reflectivity greater than 0.8.

9. The device of claim 8, wherein the reflective material comprises at least one nanofiber having a laterally extending surface for reflection of the light.

10. The device of claim 9, wherein the reflective material produces a mix of specular and diffuse reflection of light.

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

12. The device of claim 11, wherein the polymer fibers 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 6,10, nylon 6,6, polycarbonate, polyamide, polysulfone, and polyethylene terephthlate, or combinations thereof.

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

14. The device of claim 1, wherein the reflective nanocomposite mat comprises fibers having an average fiber diameter in a range between 50 to 5,000 nm.

15. The device of claim 1, wherein the reflective nanocomposite mat comprises fibers having an average fiber diameter in a range between 50 to 350 nm before application of the reflectance-enhancing coating.

16. The device of claim 1, wherein the reflective nanocomposite mat has a thickness in a range between 0.01 microns and 2,000 microns or between 1 to 500 microns.

17. The device of claim 1, wherein the reflective nanocomposite mat reflects at least 70% of all visible light from 420 nm to 720 nm.

18. The device of claim 1, wherein the reflective nanocomposite mat reflects at least 80% of all visible light from 420 nm to 720 nm.

19. The device of claim 1, wherein the reflective nanocomposite mat reflects at least 90% of all visible light from 420 nm to 720 nm.

20. A lighting device insert comprising:

a substrate having a nanocomposite mat of reflective fibers having diameters less than 1,000 nm which diffusively reflects visible light upon illumination with at least a primary light;

said nanocomposite mat including an reflectance-enhancing coating having a refractive index different from the reflective fibers and which increases a reflectance of the substrate in the visible spectrum; and

said nanocomposite mat configured to diffusively reflect at least 70% of incident light.

21. The insert of claim 20, wherein the reflectance-enhancing coating comprises a coating having a thickness of at least one of less than 20 nm, less than 200 nm, less than 2000 nm, or less than 5,000 nm.

22. The insert of claim 20, wherein a difference in refractive indices of the reflective fibers and the coating is less than 0.20 or less than 0.12.

23. The insert of claim 20, wherein the coating comprises bridge elements connected between the reflective fibers and forming light scattering sites between adjacent fibers.

24. The insert of claim 20, wherein the coating comprises nodules or segments on the reflective fibers forming light scattering sites on the fibers.

25. The insert of claim 20, wherein the reflective fibers include at least one of Al, Au, Ag, TiO₂, ZnO, BaSO₄, and Zn.

26. The insert of claim 20, wherein the reflective fibers comprises a reflective material having at least one nanofiber having a laterally extending surface for reflection of the light.

27. The insert of claim 26, wherein the reflective material produces a mix of specular and diffuse reflection of light.

28. The insert of claim 20, wherein the reflectance-enhancing coating comprises at least one of parylene coatings, perfluorosilane coatings, vacuum plasma coatings, atomic layer deposition coatings, perfluorinated coatings, phosphonate dip coatings, and silicone coatings, or mixtures thereof.

29. A method for making a reflective material, comprising:

providing a nanocomposite mat of reflective fibers having diameters less than 1,000 nm which diffusively reflects visible light; and

conformally applying an reflectance-enhancing coating of a thickness between 20 nm and 5,000 nm around an outer surface of the fibers, wherein a difference in refractive indices between the fibers and the coating is less than 0.20.

30. The method of claim 29, wherein the applying comprises applying said coating with a difference in refractive indices between the fibers and the coating which is less than 0.15.

31. The method of claim 29, wherein the applying comprises applying said coating with at least one of vapor deposition, plasma coating, dip-coating, spray coating, roller coating, extrusion coating, dip coating, inkjet printing, nanoimprint lithography, transfer coating, and dip-pen lithography.

32. The method of claim 29, wherein the applying comprises applying for said coating at least one of parylene coatings, perfluorosilane coatings, vacuum plasma coatings, atomic layer deposition coatings, perfluorinated coatings, phosphonate dip coatings, and silicone coatings, or mixtures thereof.

33. The method of claim 29, wherein the applying comprises applying for said coating a coating having a thickness of at least one of less than 20 nm, less than 200 nm, less than 2000 nm, or less than 5,000 nm.