Light Source Element with Lateral, Oblique Light Infeed

• US 20070263411A1
• Filed: 05/14/2007
• Published: 11/15/2007
• Est. Priority Date: 12/29/1998
• Status: Active Grant

• Current Assignee: OSRAM GmbH (Ams-Osram AG)
• Original Assignee: OSRAM GmbH (Ams-Osram AG)
• Inventors: Bachl, Bernhard, Brunner, Herbert, Schellhorn, Franz, Kirchberger, Gunter, Waitl, Gunter
• Granted Patent: US 7,688,401 B2
• Time in Patent Office: Days
• US Class Current: 362/615
• CPC Class Codes: G02B 6/00 Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
• CPC Class Codes: G02B 6/0001 specially adapted for lighting devices or systems lighting or signalling on vehicles using light guides B60Q1/00; lighting devices for vehicle dashboards B60Q3/10; lighting devices for vehicle interior using light guides B60Q3/62; lighting devices mounted on the vehicle rear part using light guides F21S43/235; measuring arrangements having light conducting pointers G01D13/265; illumination of liquid crystal displays G02F1/1336; illuminated signs G09F13/00
• CPC Class Codes: G02B 6/0018 Redirecting means on the surface of the light guide
• CPC Class Codes: G02B 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/4298 coupling with non-coherent light sources and/or radiation detectors, e.g. lamps, incandescent bulbs, scintillation chambers
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side
• 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 source element is employed back-lighting of liquid crystal displays and that comprises an obliquely placed light exit face and/or light entry face. At its surfaces, the light waveguide is surrounded by reflectors into which suitable aperture regions are potentially formed. A plurality of light sources and/or a more direct view is provided and, thus, a corresponding increase of the luminance results. A method is also provided for the manufacture of a light source element with an integrated reflector.

Claims

1. A light source element, comprising:

a light waveguide, comprising;

a light exit face;

a surface lying opposite the light exit face;

a plurality of lateral surfaces, each of the plurality of lateral surfaces connecting the light exit face and the surface opposite the light exit face; and

more than two light entry faces, each one of the more than two light entry faces being separated and remote from the other light entry faces,

wherein at least one member of a group consisting of each of the lateral surfaces and the surface opposite the light exit face is covered with reflectors that at least one of reflect and diffusely return light; and

wherein each light entry face is formed by a portion of at least one member of the group of surfaces, and each light entry face is positioned at an acute angle relative to one of the principal directions of extent of the waveguide.

2. The light source element of claim 1, wherein the light exit face and the surface opposite the light exit face are substantially parallel.

3. The light source element of claim 1, wherein each light entry face comprises an opening in a reflector that corresponds to a portion of an aperture region at the light waveguide.

4. The light source element of claim 3, further comprising light infeed units positioned in front of at least some of the light entry faces, each light infeed unit comprising at least one light source, so that light radiation emitted during operation of the light source enters the light waveguide at an oblique angle relative to one of the principal directions of extent of the waveguide.

5. The light source element of claim 3, wherein the aperture region comprises at least one triangular projection formed in at least one member of the group of surfaces, and wherein a first lateral surface of the triangular projection is covered by a reflector and a second lateral surface of the triangular projection is at least partially free of reflectors.

6. The light source element of claim 3, wherein two or more members of the group of surfaces each comprise two or more aperture regions.

7. The light source element of claim 6, wherein each of the aperture regions comprises a triangular projection formed in at least one member of the group of surfaces, and wherein a first lateral surface of each triangular projection is covered by a reflector and a second lateral surface of each triangular projection is at least partially free of reflectors.

8. The light source element of claim 1, wherein the reflectors are diffuse reflectors.

9. The light source element of claim 1, wherein the reflectors are integrally connected to one another.

10. The light source element of claim 1, wherein the reflectors are formed in an injection molding process from a material that is capable of being injection molded.

11. The light source element of claim 1, wherein the reflectors comprise a thermoplastic polymer on a base of polybutylene terephthalate.

12. The light source element of claim 1, wherein the reflectors comprise Pocan®

.

13. The light source element of claim 1, wherein the reflectors are formed from one of a reflective film and a diffusely back-scattering film.

14. The light source element of claim 13, wherein the film comprises a base of polycarbonate.

15. The light source element of claim 13, wherein at least some of the reflectors comprise at least one opening formed in the film for the passage of light radiation.

16. The light source element of claim 13, wherein the film is at least one of coated and printed with a material that has a substantially white color.

17. The light source element of claim 1, wherein the light source element forms a closed ring.

18. The light source element of claim 17, wherein the light source element comprises a first lateral surface that forms an inner circumference of the light waveguide and a second lateral surface that forms an outer circumference of the light waveguide, and wherein the first lateral surface comprises more than two light entry faces.

19. The light source element of claim 18, wherein the second lateral surface comprises more than two light entry faces.

20. The light source element of claim 4, wherein at least some of the light sources comprise a semiconductor light emitting diode.

21. The light source element of claim 1, wherein at least one member of the group of surfaces comprises light scattering sections and plane sections, and an area ratio of the plane sections to the light scattering sections is set so that a substantially uniform luminance of the light source element is achieved.

22. The light source element of claim 1, wherein each of the light entry faces is planar.

23. A liquid crystal display, comprising:

the light source element of claim 1;

and

a liquid crystal element proximal to the light exit face of the light waveguide and configured to receive light radiation emitted from the light exit face, wherein the liquid crystal element is spaced from the light exit face by one or more spacers.

24. The light source element of claim 1, further comprising light sources positioned in front of at least some of the light entry faces, wherein the light sources and the surface opposite the light exit surface are substantially coplanar.

25. A light source element, comprising:

a light waveguide, comprising;

a light exit face;

a surface lying opposite the light exit face;

a plurality of lateral surfaces, each of the plurality of lateral surfaces connecting the light exit face and the surface opposite the light exit face; and

at least two light entry faces, wherein each of the at least two light entry faces is separated from the other light entry faces and formed by a portion of at least one member of a group consisting of each of the plurality of lateral surfaces and the surface opposite the light exit surface, and wherein each of the at least two light entry faces is formed on a common side of the light waveguide and arranged at an acute angle relative to one of the principal directions of extent of the light waveguide,

wherein at least one member of the group consisting of the lateral surfaces and the surface opposite the light exit face is covered with reflectors that at least one of reflect and diffusely return light.

26. The light source element of claim 25, wherein the light exit face and the surface opposite the light exit face are substantially parallel.

27. The light source element of claim 25, wherein each light entry face comprises an opening in a reflector that corresponds to a portion of an aperture region at the light waveguide.

28. The light source element of claim 27, further comprising light infeed units positioned in front of at least some of the light entry faces, each light infeed unit comprising at least one light source, so that light radiation emitted during operation of the light source enters the light waveguide at an oblique angle relative to one of the principal directions of extent of the waveguide.

29. The light source element of claim 27, wherein the aperture region comprises at least one triangular projection formed in at least one member of the group of surfaces, and wherein a first lateral surface of the triangular projection is covered by a reflector and a second lateral surface of the triangular projection is at least partially free of reflectors.

30. The light source element of claim 27, wherein two or more members of the group of surfaces each comprise two or more aperture regions formed on a common side of the light waveguide.

31. The light source element of claim 30, wherein each of the aperture regions comprises a triangular projection formed in at least one member of the group of surfaces, and wherein a first lateral surface of each triangular projection is covered by a reflector and a second lateral surface of each triangular projection is at least partially free of reflectors.

32. The light source element of claim 25, wherein the reflectors are diffuse reflectors.

33. The light source element of claim 25, wherein the reflectors are integrally connected to one another.

34. The light source element of claim 25, wherein the reflectors are formed in an injection molding process from a material that is capable of being injection molded.

35. The light source element of claim 25, wherein the reflectors comprise a thermoplastic polymer on a base of polybutylene terephthalate.

36. The light source element of claim 25, wherein the reflectors comprise Pocan®

.

37. The light source element of claim 25, wherein the reflectors are formed from one of a reflective film and a diffusely back-scattering film.

38. The light source element of claim 37, wherein the film comprises a base of polycarbonate.

39. The light source element of claim 37, wherein at least some of the reflectors comprise at least one opening formed in the film for the passage of light radiation.

40. The light source element of claim 37, wherein the film is at least one of coated and printed with a material that has a substantially white color.

41. The light source element of claim 25, wherein the light source element forms a closed ring.

42. The light source element of claim 41, wherein the light source element comprises a first lateral surface that forms an inner circumference of the light waveguide and a second lateral surface that forms an outer circumference of the light waveguide, and wherein the first lateral surface comprises two or more light entry faces on a common side of the light waveguide.

43. The light source element of claim 42, wherein the second lateral surface comprises two or more light entry faces on a common side of the light waveguide.

44. The light source element of claim 28, wherein at least some of the light sources comprise a semiconductor light emitting diode.

45. The light source element of claim 25, wherein at least one member of the group of surfaces comprises light scattering sections and plane sections, and an area ratio of the plane sections to the light scattering sections is set so that a substantially uniform luminance of the light source element is achieved.

46. The light source element of claim 25, wherein each of the light entry faces is planar.

47. A liquid crystal display, comprising:

the light source element of claim 25;

and

a liquid crystal element proximal to the light exit face of the light waveguide and configured to receive light radiation emitted from the light exit face, wherein the liquid crystal element is spaced from the light exit face by one or more spacers.

48. The light source element of claim 25, further comprising light sources positioned in front of at least some of the light entry faces, wherein the light sources and the surface opposite the light exit surface are substantially coplanar.

49. A light source element, comprising:

a light waveguide, comprising;

a light exit face;

a surface lying opposite the light exit face;

a plurality of lateral surfaces, each of the plurality of lateral surfaces connecting the light exit face and the surface opposite the light exit face; and

at least one aperture region comprising a first portion of a first surface selected from a group consisting of each of the plurality of lateral surfaces and the surface opposite the light exit face, the first portion being free of reflectors, and further comprising second and third portions of the first surface adjacent to the first portion and on opposite sides of the first portion, and covered by reflectors,

wherein at least one member of the group of surfaces is covered with reflectors that at least one of reflect and diffusely return light; and

wherein a light entry face is formed within said aperture region by the first portion, and the light entry face is positioned at an acute angle relative to one of the principal directions of extent of the waveguide.

50. The light source element of claim 49, wherein the light exit face and the surface opposite the light exit face are substantially parallel.

51. The light source element of claim 49, further comprising light infeed units positioned in front of at least some of the light entry faces, each light infeed unit comprising at least one light source, so that light radiation emitted during operation of the light source enters the light waveguide at an oblique angle relative to one of the principal directions of extent of the waveguide.

52. The light source element of claim 49, wherein said aperture region comprises a triangular projection formed in at least one member of the group consisting of the lateral surfaces and the surface opposite the light exit face, and wherein a first lateral surface of the triangular projection is covered by a reflector and a second lateral surface of the triangular projection is at least partially free of reflectors.

53. The light source element of claim 49, wherein two or more members of the group of surfaces each comprise more than one aperture region.

54. The light source element of claim 53, wherein each of said aperture regions comprises a triangular projection formed in at least one member of the group of surfaces, and wherein a first lateral surface of each triangular projection is covered by a reflector and a second lateral surface of each triangular projection is at least partially free of reflectors.

55. The light source element of claim 49, wherein the reflectors are diffuse reflectors.

56. The light source element of claim 49, wherein the reflectors are integrally connected to one another.

57. The light source element of claim 49, wherein the reflectors are formed in an injection molding process from a material that is capable of being injection molded.

58. The light source element of claim 49, wherein the reflectors comprise a thermoplastic polymer on a base of polybutylene terephthalate.

59. The light source element of claim 49, wherein the reflectors comprise Pocan®

.

60. The light source element of claim 49, wherein the reflectors are formed from one of a reflective film and a diffusely back-scattering film.

61. The light source element of claim 60, wherein the film comprises a base of polycarbonate.

62. The light source element of claim 60, wherein at least some of the reflectors comprise at least one opening formed in the film for the passage of light radiation.

63. The light source element of claim 60, wherein the film is at least one of coated and printed with a material that has a substantially white color.

64. The light source element of claim 49, wherein the light source element forms a closed ring.

65. The light source element of claim 64, wherein the light source element comprises a first lateral surface that forms an inner circumference of the light waveguide and a second lateral surface that forms an outer circumference of the light waveguide, and wherein the first lateral surface comprises at least one aperture region.

66. The light source element of claim 65, wherein the second lateral surface comprises at least one aperture region.

67. The light source element of claim 51, wherein at least some of the light sources comprise a semiconductor light emitting diode.

68. The light source element of claim 49, wherein at least one member of the group of surfaces comprises light scattering sections and plane sections, and an area ratio of the plane sections to the light scattering sections is set so that a substantially uniform luminance of the light source element is achieved.

69. The light source element of claim 49, wherein each of the light entry faces is planar.

70. A liquid crystal display, comprising:

the light source element of claim 49;

and

a liquid crystal element proximal to the light exit face of the light waveguide and configured to receive light radiation emitted from the light exit face, wherein the liquid crystal element is spaced from the light exit face by one or more spacers.

71. The light source element of claim 49, further comprising light sources positioned in front of at least some of the aperture regions, wherein the light sources and the surface opposite the light exit surface are substantially coplanar.