Visual display device with fluorescent dye-doped edge-illuminating emitter panel

• US 4,989,956 A
• Filed: 01/04/1989
• Issued: 02/05/1991
• Est. Priority Date: 01/04/1989
• Status: Expired due to Fees

• Current Assignee: Hughes Electronics Corporation (Rtx Corporation)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Hsu, Tsung Y., Wu, Wei-Yu, Lackner, Anna M., Smith, Willis H. Jr.
• Primary Examiner(s): Arnold, Bruce Y.
• Assistant Examiner(s): Ryan, J. P.
• Application Number:
  US07/293,875
• Time in Patent Office: 762 Days
• Field of Search: 350/3.7, 350/3.85, 350/345, 350/331 R, 350/350 F, 354/53, 40/546
• US Class Current: 349/71
• CPC Class Codes: B60Q 1/44 for indicating braking action or preparation for braking, e.g. by detection of the foot approaching the brake pedal
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0041 provided in the bulk of the light guide
• CPC Class Codes: G02B 6/0071 with elongated shape, e.g. tube
• CPC Class Codes: G09F 13/0472 Traffic signs
• CPC Class Codes: G09F 19/205 Special effects using different wavelengths
• CPC Class Codes: G09F 2013/185 Embossed marks
• CPC Class Codes: G09F 2013/1854 Light diffusing layer
• CPC Class Codes: G09F 2013/1868 Fluorescent pencil
• CPC Class Codes: G09F 9/35 being liquid crystals G09F9/302 takes precedence; liquid crystal materials C09K19/00; liquid crystal panels comprising a number of electrodes in a single cell per se G02F1/13

Abstract

A light emitting panel is formed of a transparent plastic substrate doped with fluorescent dye which absorbs incident light through a relatively large surface area and emits light of a longer wavelength out through one edge. The incident light may be ambient or produced by a fluorescent light source. The edge emitted light is optically coupled into an edge of a display panel, which may be a polymer dispersed liquid crystal display or a plastic panel having a display surface formed with an etched or printed pattern, grating or hologram. The substrate materials of the emitting and display panels, as well as an optical adhesive which joins the edges thereof, preferably have an essentially similar index of refraction which is larger than that of air causing light propagating through the panels to be internally reflected and exit the structure only through the pattern on the display surface. The display panel is preferably transparent in the absence of light incident on the emitting panel, and produces a display visible from only one direction upon application of incident light. The display panel may be constituted as a center-high-mounted stop light for an automotive vehicle.

Claims

1. A visual display device, comprising:

display panel means formed with a display pattern on a surface thereof and having a light receiving edge and

fluorescent dye doped emitter panel means for absorbing light incident upon a surface thereof and emitting light through an edge thereof, said edges of said emitter and display panel means being optically coupled to each other for edge illumination of said display pattern, said emitter and display panel means each comprising light transmitting substrates.

2. A visual display device as in claim 1, in which said substrates of the emitter and display panels have a substantially equal index of refraction.

3. A visual display device as in claim 2, further comprising an optical adhesive for adhering said respective edges of the emitter and display panel means together, the optical adhesive and said substrates having an essentially similar index of refraction.

4. A visual display device as in claim 1, in which said substrates are optically transparent.

5. A visual display device as in claim 1, in which the fluorescent dye comprises a material which absorbs light at a first wavelength, and emits light at a second wavelength which is longer than the first wavelength.

6. A visual display device as in claim 1, in which the display pattern comprises grooves formed in said surface.

7. A visual display device as in claim 6, in which the display pattern further comprises ink applied in the grooves.

8. A visual display device as in claim 1, in which the display pattern comprises a hologram.

9. A visual display device as in claim 8, in which the hologram is a volume hologram.

10. A visual display device as in claim 1, in which the display pattern comprises an optical diffraction grating.

11. A visual display device as in claim 1, in which the display pattern comprises printing.

12. A visual display device as in claim 11, in which the printing comprises a pattern formed of ink.

13. A visual display device as in claim 12, in which the ink comprises a light reflecting material.

14. A visual display device as in claim 12, in which the ink further comprises a light diffusing material.

15. A visual display device as in claim 1, further comprising light source means for illuminating said surface of the emitter panel means.

16. A visual display device as in claim 15, in which the light source means comprises a fluorescent lamp.

17. A visual display device as in claim 15, in which the light source means comprises a fluorescent light emitting element and a reflector for reflecting light emitted by the light emitting element toward said surface of the emitter panel means.

18. A visual display device as in claim 15, in which the emitter panel means comprises an elongated sheet formed into a spiral shape, the light source means being disposed at substantially a center of the spiral shape.

19. A visual display device as in claim 15, in which the emitter panel means comprises a fluorescent dye doped sheet formed into a generally cylindrical shape with adjacent edges extending radially outwardly therefrom, the light source means being disposed at substantially a center of the cylindrical shape.

20. A visual display device as in claim 15, in which the emitter panel means comprises two U-shaped sections and two light sources embraced by the U-shaped sections respectively, each U-shaped section having a first edge which is optically coupled to the display panel means.

21. A visual display device as in claim 20, in which each U-shaped section has a second edge opposite the first edge provided with means for preventing light from propagating therethrough.

22. A visual display device as in claim 1, in which the display panel means is configured as an automotive center-high-mounted stop light.

23. A visual display device as in claim 1, in which the display panel means comprises a liquid crystal display.

24. A visual display device as in claim 1, in which the liquid crystal display comprises a polymer dispersed liquid crystal module.

25. A visual display device as in claim 24, in which the liquid crystal display further comprises a fluorescent dye material formed on at least one surface of the polymer dispersed liquid crystal module.

26. A stoplight device for an automotive vehicle, comprising:

fluorescent dye doped emitter panel means for absorbing light incident upon a surface thereof and emitting light through an edge thereof;

light source means for radiating light onto said surface of the emitter panel means in response to application of a vehicle brake; and

display panel means formed with a stoplight display pattern on a surface thereof and having an edge which is optically coupled to said edge of the emitter panel means for edge illumination of the display pattern.

27. A stoplight device as in claim 26, in which the emitter panel means and display panel means each comprise light transmitting substrates, the device further comprising an optical adhesive for adhering said respective edges of the emitter and display panels together, the optical adhesive having an index of refraction which is essentially similar to that of said substrates.

28. A stoplight device as in claim 27, in which said index of refraction is larger than the index of refraction of air, whereby a larger proportion of light propagating inside said substrates is reflected internally than is transmitted externally thereof.

29. A stoplight device as in claim 26, in which the fluorescent dye comprises a material which absorbs light at a first wavelength and emits light at a second wavelength which is longer than the first wavelength.

30. A stoplight device as in claim 26, in which the display pattern comprises grooves formed in said surface.

31. A stoplight device as in claim 30, in which the display pattern further comprises ink applied in the grooves.

32. A stoplight device as in claim 26, in which the display pattern comprises a hologram.

33. A stoplight device as in claim 32, in which the hologram comprises a volume hologram.

34. A stoplight device as in claim 26, in which the display pattern comprises an optical diffraction grating.

35. A stoplight device as in claim 26, in which the display pattern comprises printing.

36. A stoplight devices as in claim 35, in which printing comprises a pattern formed of ink.

37. A stoplight device as in claim 36, in which the ink comprises a light reflecting material.

38. A stoplight device as in claim 36, in which the ink comprises a light diffusing material.

39. A stoplight device as in claim 26, in which the light source means comprises a fluorescent lamp which emits light at a wavelength which is substantially equal to a maximum absorption wavelength of the fluorescent dye in the emitter panel means.

40. A liquid crystal display device, comprising:

fluorescent dye doped emitter panel means for absorbing light incident upon a surface thereof and emitting light through an edge thereof; and

liquid crystal display panel means having a display pattern on a surface thereof and having an edge which is optically coupled to said edge of the emitter panel means for edge illumination of the display pattern.

41. A liquid crystal display device as in claim 40, in which the liquid crystal display panel means comprises a polymer dispersed liquid crystal module.

42. A liquid crystal display device as in claim 41, further comprising light source means for radiating light onto said surface of the emitter panel means.

43. A liquid crystal display device as in claim 40, in which the emitter panel means comprises a liquid crystal material and electrode means which sandwich the liquid crystal material therebetween to form a display pattern which is changeable between a transparent state and a light scattering state in response to an electric potential applied to the electrode means.

44. A liquid crystal display device as in claim 43, further comprising a fluorescent dye material formed on surfaces of the electrode means.

45. A liquid crystal display device as in claim 40, in which the emitter panel means and display panel means each comprise light transmitting substrates, the device further comprising an optical adhesive for adhering said respective edges of the emitter and display panels together of the optical adhesive having an index of refraction which is essentially similar to that of said substrates.

46. A liquid crystal display device as in claim 45, in which said index of refraction is larger than the index of refraction of air, whereby a larger proportion of light propagating inside said substrates is reflected internally than is transmitted externally thereof.

47. A liquid crystal display device as in claim 40, in which the fluorescent dye comprises a material which absorbs light at a first wavelength, and emits light at a second wavelength which is longer than the first wavelength.

48. A liquid crystal display device as in claim 40, in which the emitter panel means comprises two U-shaped sections and two light sources embraced by the U-shaped sections respectively, each U-shaped section having a first edge which is optically coupled to the display panel means.