Photolytically and environmentally stable multilayer structure for high efficiency electromagnetic energy conversion and sustained secondary emission

• US 8,415,642 B2
• Filed: 09/30/2011
• Issued: 04/09/2013
• Est. Priority Date: 09/30/2010
• Status: Active Grant

• Current Assignee: Performance Indicator, LLC
• Original Assignee: Performance Indicator, LLC
• Inventors: Kingsley, Edward D., Horner, M. Glenn, Agrawal, Satish, Cincotta, Louis
• Primary Examiner(s): Kim, Kiho
• Application Number:
  US13/249,350
• Publication Number:
  US 20120080613A1
• Time in Patent Office: 557 Days
• Field of Search: 250/459.1
• US Class Current: 250/459.1
• CPC Class Codes: C09K 11/025 non-luminescent particle coatings or suspension media
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: F21V 13/14 the elements being filters or photoluminescent elements, reflectors and refractors
• CPC Class Codes: F21V 9/06 for filtering out ultraviolet radiation
• CPC Class Codes: F21V 9/08 for producing coloured light, e.g. monochromatic; for reducing intensity of light with provision for controlling the colour F21V9/40
• CPC Class Codes: F21V 9/38 Combination of two or more photoluminescent elements of different materials
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/31504 Composite [nonstructural laminate]

Abstract

A multilayer structure for sustained conversion of a primary electromagnetic radiation into another electromagnetic radiation characterized by a spectrum of a higher average wavelength is disclosed. Also disclosed are methods of creating and using the inventive multilayer structure.

Claims

1. A multilayer structure for sustained energy conversion of a primary electromagnetic radiation, said multilayer structure comprising:

(i) an energy conversion layer for converting the energy of the primary electromagnetic radiation to a longer output wavelength, the energy conversion layer comprising a polymer and a first photoluminescent material characterized by a first Stokes shift and a first radiation absorption spectrum which at least partially overlaps with the spectrum of the primary electromagnetic radiation; and

(ii) at least one stability enhancement layer increasing the photolytic and thermal stability of the energy conversion layer.

2. The multilayer structure of claim 1, wherein said polymer in said energy conversion layer is photolytically and thermally stable.

3. The multilayer structure of claim 1, wherein said first photoluminescent material and said polymer in said energy conversion layer comprise a solid state solution.

4. The multilayer structure of claim 1, wherein said primary electromagnetic radiation emanates from within the multilayer structure.

5. The multilayer structure of claim 1, wherein said primary electromagnetic radiation is ambient light.

6. The multilayer structure of claim 1, wherein said energy conversion layer further comprises a high persistence photoluminescent material, and wherein the primary electromagnetic radiation emanates from the high persistence photoluminescent material.

7. The multilayer structure of claim 1, wherein the primary electromagnetic radiation emanates from at least one of an electroluminescent source, a solid state device or a chemiluminescent source.

8. The multilayer structure of claim 1, wherein said first photoluminescent material comprises an organic fluorescent dye.

9. The multilayer structure of claim 1, further comprising a second photoluminescent material characterized by a second Stokes shift and a second radiation absorption spectrum which at least partially overlaps with the spectrum of the radiation emission of said first photoluminescent material.

10. The multilayer structure as in claim 1 or 9, wherein said energy conversion layer further comprises a light scattering element.

11. The multilayer structure as in claim 1 or 9, further comprising a reflection layer, said reflection layer redirects radiation emitted in said energy conversion layer to the viewing hemisphere.

12. The multilayer structure of claim 11, wherein said reflection layer transmits at least a portion of the primary electromagnetic radiation.

13. The multilayer structure of claim 11, wherein the reflection layer additionally fulfills the function of the at least one stability enhancement layer.

14. The multilayer structure of claim 11, wherein the energy conversion layer, the at least one stability enhancement layer and the reflection layer are rendered as a multilayer discrete particle.

15. The multilayer structure of claim 11, wherein said reflection layer being at least one of a specular reflection or a diffuse reflection.

16. The multilayer structure of claim 11, wherein said reflection layer comprises a plurality of alternate layers of non-metallic materials with high and low dielectric constants.

17. The multilayer structure of claim 11, wherein said reflection layer is a lenticular element or a microprismatic element.

18. The multilayer structure as in claim 1 or 9, further comprising a diffusion layer, said diffusion layer increases optical scattering.

19. The multilayer structure of claim 18, further comprising a reflection layer, wherein the reflection layer redirects radiation emitted in at least one of the energy conversion layer or the diffusion layer.

20. The multilayer structure of claim 18, wherein the energy conversion layer, the at least one stability enhancement layer, and the diffusion layer are rendered as a multilayer discrete particle.

21. The multilayer structure as in claim 1 or 9, further comprising a protective layer, said protective layer provides mechanical and chemical durability for at least said energy conversion layer.

22. The multilayer structure of claim 21, wherein the energy conversion layer, the at least one stability enhancement layer, and the protective layer are rendered as a multilayer discrete particle.

23. The multilayer structure as in claim 1 or 9, wherein the energy conversion layer comprises at least a single layer of discrete particles.

24. The multilayer structure as in claim 1 or 9, wherein one said at least one stability enhancement layer is rendered on a first side of the energy conversion layer and another said at least one stability enhancement layer is rendered on another side of the energy conversion layer.

25. The multilayer structure as in claim 1 or 9, wherein the energy conversion layer and the at least one stability enhancement layer are rendered as a multilayer discrete particle.

26. The multilayer structure as in claim 1 or 9, wherein the energy conversion layer further comprises a singlet oxygen quencher.

27. The multilayer structure of claim 1, wherein the primary electromagnetic radiation is infrared, visible, ultraviolet, or any combination thereof.

28. The multilayer structure of claim 1, wherein the longer output wavelength is infrared, visible, ultraviolet, or any combination thereof.

29. The multilayer structure of claim 1, wherein the primary electromagnetic radiation emanates from a waveguide that is either coupled or decoupled from an electroluminescent source.

30. The multilayer structure of claim 29, wherein said energy conversion layer is positioned over at least a surface of the waveguide that is remote to the electroluminescent source.

31. The multilayer structure of claim 29, wherein at least a portion of a surface of the waveguide is etched to extract light from the waveguide, said surface being remote to the electroluminescent source.

32. The multilayer structure of claim 1, further comprising at least one optical variable element, said at least one optical variable element varies the longer output wavelength that is observed as a function of viewing angle.

33. The multilayer structure of claim 32, wherein said at least one optical variable element comprises one or more discrete elements, said one or more discrete elements are a lenticular lens or a prismatic lens.

34. A method for sustained energy conversion of a primary electromagnetic radiation, said method comprising:

providing a multilayer structure for sustained energy conversion of the primary electromagnetic radiation, said multilayer structure comprising;

(i) an energy conversion layer comprising a polymer and a first photoluminescent material characterized by a first Stokes shift and a first radiation absorption spectrum which at least partially overlaps with the spectrum of the primary electromagnetic radiation;

(ii) at least one stability enhancement layer increasing the photolytic and thermal stability of the energy conversion layer;

exposing the energy conversion layer to the primary electromagnetic radiation; and

converting energy of the primary electromagnetic radiation to a longer output wavelength.

35. The method of claim 34, wherein the multilayer structure further comprises a second photoluminescent material characterized by a second Stokes shift and a second radiation absorption spectrum which at least partially overlaps with the spectrum of the radiation emission of said first photoluminescent material.

36. The method as in claim 34 or 35, wherein the multilayer structure further comprises a reflection layer, said reflection layer redirects radiation emitted in said energy conversion layer.

37. The method as in claim 34 or 35, wherein the multilayer structure further comprises a diffusion layer, said diffusion layer increases optical scattering.

38. The method of claim 37, wherein the multilayer structure further comprises a reflection layer, said reflection layer redirects radiation emitted in at least one of the energy conversion layer or the diffusion layer.

39. The method as in claim 34 or 35, wherein the multilayer structure further comprises a protective layer, said protective layer provides physical and chemical durability for at least the energy conversion layer.

40. A method of forming a multilayer structure for sustained energy conversion of a primary electromagnetic radiation, said method comprising:

forming an energy conversion layer comprising a first photoluminescent material characterized by a first Stokes shift and a first radiation absorption spectrum that at least partially overlaps with the spectrum of the primary electromagnetic radiation; and

overlaying at least one stability enhancement layer over at least one side of the energy conversion layer to increase the photolytic and thermal stability of the energy conversion layer.

41. The method of claim 40, wherein the multilayer structure further comprises a second photoluminescent material characterized by a second Stokes shift and a second radiation absorption spectrum which at least partially overlaps with the spectrum of the radiation emission of said first photoluminescent material.

42. The method as in claim 40 or 41, further comprising applying a diffusion layer disposed over at least one side of the energy conversion layer, wherein the diffusion layer increases optical scattering.

43. The method of claim 42, further comprising rendering a reflection layer disposed over one side of the diffusion layer, wherein the reflection layer redirects radiation emitted in at least one of the energy conversion layer or the diffusion layer.

44. The method as in claim 40 or 41, further comprising rendering a reflection layer disposed over one side of the energy conversion layer, wherein said reflection layer redirects radiation emitted in the energy conversion layer.

45. The method as in claim 40 or 41, further comprising overlaying a protective layer over a surface of the at least one stability enhancement layer, said surface not having another layer disposed on said surface, wherein the protective layer protects the multilayer structure physically and chemically.