Light Emissive Signage Devices Based on Lightwave Coupling

• US 20070031097A1
• Filed: 09/27/2006
• Published: 02/08/2007
• Est. Priority Date: 12/08/2003
• Status: Active Grant

• Current Assignee: University of Cincinnati
• Original Assignee: University of Cincinnati
• Inventors: Heikenfeld, Jason, Rudolph, John, Steckl, Andrew
• Granted Patent: US 7,430,355 B2
• Time in Patent Office: Days
• US Class Current: 385/129
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: Y10S 385/901 Illuminating or display apparatus

Abstract

A signage device comprising one or more light sources, a waveguide or arrangement of waveguides and photoluminescent features coupled thereto. In one embodiment, a waveguide is adapted to receive light of a first wavelength and the photoluminescent features are adapted to emit light of a second wavelength in response to receiving light of the first wavelength.

Claims

1. A signage device comprising:

a waveguide adapted to propagate light of a first wavelength shorter than about 450 nm; and

at least one photoluminescent feature coupled with the waveguide for receiving the light of the first wavelength, the at least one photoluminescent feature adapted to emit light of a second wavelength between about 420 nm and about 650 nm in response to receiving the light of the first wavelength.

2. The signage device of claim 1 wherein the waveguide includes a reflective surface operating to reduce loss of the light of the first wavelength by reflection.

3. The signage device of claim 2 wherein the reflective surface includes a surface finish capable of enhancing retention of the light of the first wavelength within the waveguide by total internal reflection (TIR).

4. The signage device of claim 2 wherein the waveguide has a major dimension such that a number of reflections of the light of the first wavelength along the major dimension is at least one.

5. The signage device of claim 1 further comprising:

a light source adapted to emit the light of the first wavelength; and

a reflective surface arranged relative to the light source so as to direct the light of the first wavelength into the waveguide.

6. The signage device of claim 5 wherein the reflective surface has a primarily parabolic geometrical shape or a primarily elliptical geometrical shape.

7. The signage device of claim 5 further comprising:

an optical element disposed between the waveguide and the light source.

8. The signage device of claim 1 wherein the waveguide is composed of a material that is substantially free of substances absorptive of light in a wavelength band between about 350 nm and about 420 nm.

9. The signage device of claim 1 wherein the waveguide further comprises a thin, flexible substrate carrying the at least one photoluminescent feature.

10. The signage device of claim 9 wherein the thin, flexible substrate is configured to adhere to a thicker substrate.

11. The signage device of claim 1 further comprising:

a plurality of light sources adapted to emit the light of the first wavelength, each of the light sources coupled with the waveguide.

12. The signage device of claim 11 further comprising a plurality of photoluminescent features, wherein the light sources may be operated to temporally sequence the light of the first wavelength for coupling with different photoluminescent features to create multiple images.

13. The signage device of claim 1 further comprising:

an antireflective coating on the at least one photoluminescent feature and the waveguide.

14. The signage device of claim 1 further comprising:

a scratch-resistant coating on the at least one photoluminescent feature and the waveguide.

15. The signage device of claim 1 wherein the at least one photoluminescent feature further comprises a primary color luminescent ink having an optical transparency of about 50% or greater.

16. The signage device of claim 1 further comprising:

a background layer arranged relative to said waveguide, the background layer carrying a feature visible to a viewer through the waveguide.

17. The signage device of claim 1 wherein the at least one photoluminescent feature comprises an acrylic host medium, light stable fluorescent particles in the acrylic host medium, and ultra-violet stabilizer additives in the acrylic host medium.

18. The signage device of claim 1 wherein the at least one photoluminescent feature comprises an ultraviolet curable clear ink.

19. The signage device of claim 1 wherein the at least one photoluminescent feature comprises an ink with a lifetime exceeding about 500 hours before exhibiting a fluorescence intensity loss of about 10% or greater.

20. The signage device of claim 1 further comprising:

a plurality of photoluminescent features each including one of a plurality of primary-color luminescent inks capable of creating full color spectrum images corresponding to a minimum Maxwell triangle of (0.3, 0.4) (0.4, 0.3) (0.3, 0.3) as depicted on a 1931 CIE Chromaticity diagram.

21. The signage device of claim 1 wherein the at least one photoluminescent feature comprises a white primary-color luminescent ink corresponding to a white point temperature of at least 4500 Kelvin.

22. The signage device of claim 1 wherein the at least one photoluminescent feature comprises a luminescent ink of internal quantum optical efficiency of about 80% or more for light of the first wavelength and in a wavelength band between about 350 nm and about 420 nm.

23. The signage device of claim 1 whereby the waveguide has a luminance non-uniformity less than about 0.5.

24. The signage device of claim 1 further comprising a plurality of photoluminescent features applied to the waveguide in a predominantly overlapping pattern.

25. The signage device of claim 24 wherein the second wavelength of each of the photoluminescent features is a primary color selected from the group consisting of red, green, and blue.

26. The signage device of claim 25 wherein the red photoluminescent features are between the green photoluminescent features and the waveguide, and the green photoluminescent features are between the blue photoluminescent features and the waveguide.

27. The signage device of claim 1 further comprising:

a plurality of photoluminescent features applied to the waveguide in a predominantly non-overlapping pattern.

28. The signage device of claim 1 wherein the photoluminescent features have different sizes.

29. The signage device of claim 1 wherein the waveguide includes a lenticular surface or a prismatic surface adapted to steer the light of the second wavelength from the at least one photoluminescent feature to a viewer.

30. The signage device of claim 1 further comprising:

a light source emitting the light at the first wavelength within a wavelength band between about 380 nm and about 420 nm.

31. The signage device of claim 1 further comprising:

a light source coupled with the waveguide, the light source selected from the group consisting of a fluorescent tube, a light emitting diode, a solid-state laser, and a remotely directed arc lamp.

32. The signage device of claim 1 further comprising:

a light source coupled with the waveguide, the light source at least partially comprising a substance that emits the light of the first wavelength primarily within a wavelength band between about 380 nm and about 420 nm.

33. The signage device of claim 1 further comprising:

a light source coupled with the waveguide, the light source adapted to inject the light of the first wavelength into the waveguide.

34. The signage device of claim 33 further comprising:

a control device for controlling a property of the light source.

35. The signage device of claim 33 wherein the light source is adapted to be powered by a wireless technique.

36. The signage device of claim 33 wherein the light source includes one or more reflective surfaces or refractive surfaces for controlling an entry angle of the light of the first wavelength into the waveguide.

37. The signage device of claim 33 further comprising:

a coupling element coupling the light source with the waveguide, the waveguide and the coupling element having approximately equal indices of refraction.

38. The signage device of claim 33 wherein the light source is physically embedded within the waveguide.

39. The signage device of claim 38 wherein the waveguide has a peripheral edge, and further comprising:

a reflective film or a polished surface disposed about the peripheral edge.

40. The signage device of claim 1 wherein the light source is portable, and the waveguide comprises a part of an existing structure.

41. The signage device of claim 1 wherein the at least one photoluminescent feature is optically coupled with the waveguide.

42. A display comprising:

a plurality of the signage devices of claim 1 having a two dimensional arrangement or a three dimensional arrangement; and

a plurality of light sources adapted to emit the light of the first wavelength, each of the light sources coupled with a respective one of the signage devices.

43. A signage device comprising:

a plurality of waveguides each adapted to propagate light of a first wavelength shorter than about 450 nm, the waveguides arranged with an overlapping relationship; and

at least one photoluminescent feature coupled with each of the waveguides for receiving the light of the first wavelength, the at least one photoluminescent feature adapted to emit light of a second wavelength between about 420 nm and about 650 nm in response to receiving the light of the first wavelength, and the light of the second wavelength emitted from the at least one photoluminescent feature of at least one of the waveguides being transmitted to a viewer through at least another of the waveguides.

44. The signage device of claim 43 where adjacent pairs of the waveguides are separated by at least one of an optical barrier film or a coating such that multiple images can be created and electro-optically controlled.

45. The signage device of claim 43 further comprising:

means for maximizing collection efficiency and entrance angle of the light of the first wavelength into the waveguides.

46. The signage device of claim 45 wherein the means comprises one or more lenses.

47. The signage device of claim 43 further comprising:

a columnar light source adapted to emit the light of the first wavelength, the waveguides being wrapped about the columnar light source such that each of the waveguides independently receives a portion of the light of the first wavelength.

48. The signage device of claim 47 further comprising:

at least one optical element on the columnar light source to steer the light of the first wavelength into the waveguides.

49. The signage device of claim 43 further comprising:

a plurality of light sources adapted to emit the light of the first wavelength, each of the light sources optically coupled with a respective one of the waveguides.

50. The signage device of claim 49 further comprising:

a control for operating the light sources to temporally sequence the light of the first wavelength from each of the light sources for optically coupling with the photoluminescent features on different waveguides to create multiple images.