LED LIGHT EXTRACTION BAR AND INJECTION OPTIC FOR THIN LIGHTGUIDE

• US 20080260328A1
• Filed: 04/20/2007
• Published: 10/23/2008
• Est. Priority Date: 04/20/2007
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Epstein, Kenneth A.
• Application Number:
  US11/738,172
• Publication Number:
  US 20080260328A1
• Time in Patent Office: Days
• US Class Current: 385/32
• CPC Class Codes: G02B 6/0018 Redirecting means on the surface of the light guide
• CPC Class Codes: G02B 6/0028 Light guide, e.g. taper
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]

Abstract

An optical system for back-illuminating a display has a lightguide having a confinement direction and a first plurality of light sources disposed proximate a first edge of the lightguide. Light from at least one of the light sources defines an emission axis which is approximately parallel to the confinement direction. A solid light injector is disposed to couple light from the light sources into the lightguide. A surface of the light injector may be shaped as a confinement curve for confining light from the first plurality of light sources in the confinement direction by total internal reflection. In some embodiments a portion of the illumination light from the one or more light sources enters the first light injector along a direction having a component directed away from the lightguide and is totally internally reflected within the injector.

Claims

1. An optical system, comprising:

a lightguide having a confinement direction;

a first plurality of light sources disposed proximate a first edge of the lightguide, light from at least a first light source of the first plurality of light source being directed substantially around an emission axis, the emission axis being approximately parallel to the confinement direction; and

a solid first light injector disposed to couple light from the first plurality of light sources into the lightguide, the first light injector having a first surface, at least a first portion of the first surface being shaped as a confinement curve for confining light from the first plurality of light sources in the confinement direction by total internal reflection.

2. A system as recited in claim 1, wherein a second portion of the first surface is straight.

3. A system as recited in claim 1, wherein a second portion of the first surface is curved.

4. A system as recited in claim 3, wherein the second portion of the first surface comprises a parabolic surface.

5. A system as recited in claim 1, wherein a second portion of the first surface comprises a reflectorized surface.

6. A system as recited in claim 1, wherein the first light injector comprises a second surface, at least a portion of the second surface being straight.

7. A system as recited in claim 1, wherein the first light injector comprises a second surface, at least a portion of the second surface being curved.

8. A system as recited in claim 7, wherein the second surface comprises a parabolic surface portion.

9. A system as recited in claim 1, further comprising a second plurality of light sources disposed proximate a second edge of the lightguide and a solid second light injector disposed to couple light from the second plurality of light sources into the lightguide.

10. A system as recited in claim 9, wherein the second light injector has a first surface, at least a first portion of the first surface being shaped as a confinement curve for confining light from the second plurality of light sources in the confinement direction by total internal reflection.

11. A system as recited in claim 1, wherein light is extracted from the lightguide and further comprising a display panel disposed for illumination by the light extracted from the lightguide and a controller coupled to the display panel to control an image displayed by the display panel.

12. A system as recited in claim 11, further comprising one or more light management films disposed between the lightguide and the display panel.

13. A system as recited in claim 1, wherein the first injector is non-reflectorized.

14. A system as recited in claim 1, wherein at least the first light source comprises a light emitting diode (LED).

15. A system as recited in claim 14, wherein the first light source further comprises a phosphor disposed so as to convert at least some of the light emitted by the LED at a first wavelength to light at a second wavelength different from the first wavelength.

16. A system as recited in claim 14, wherein the first plurality of light sources comprises at least a first LED capable of emitting light of a first color and at least a second LED capable of emitting light of a second color different from the first color.

17. An optical system, comprising:

a lightguide having a confinement direction;

a first plurality of light sources capable of emitting light generally about respective emission axes parallel to the confinement direction;

a first, non-reflectorized light injector disposed to couple light from the first plurality of light sources to the lightguide, the first injector directing the light from the first plurality of light sources to the lightguide.

18. A system as recited in claim 17, wherein the first light injector is shaped so that light entering the first injector is substantially all reflected towards the lightguide via one or more total internal reflections.

19. A system as recited in claim 17, wherein the first light injector has a first surface, at least a first portion of the first surface being shaped as a confinement curve for confining light from the first plurality of light sources in the confinement direction.

20. A system as recited in claim 19, wherein a second portion of the first surface is straight.

21. A system as recited in claim 19, wherein a second portion of the first surface is curved.

22. A system as recited in claim 21, wherein the second portion of the first surface comprises a parabolic surface.

23. A system as recited in claim 19, wherein the first light injector comprises a second surface, at least a portion of the second surface being straight.

24. A system as recited in claim 19, wherein the first light injector comprises a second surface, at least a portion of the second surface being curved.

25. A system as recited in claim 17, further comprising a second plurality of light sources disposed proximate a second edge of the lightguide and a solid second light injector disposed to couple light from the second plurality of light sources into the lightguide.

26. A system as recited in claim 25, wherein the second light injector has a first surface, at least a first portion of the first surface being shaped as a confinement curve for confining light from the second plurality of light sources in the confinement direction by total internal reflection.

27. A system as recited in claim 17, wherein light is extracted from the lightguide and further comprising a display panel disposed for illumination by the light extracted from the lightguide and a controller coupled to the display panel to control an image displayed by the display panel.

28. A system as recited in claim 27, further comprising one or more light management films disposed between the lightguide and the display panel.

29. A system as recited in claim 17, wherein the first plurality of light sources comprises light emitting diodes (LEDs).

30. A system as recited in claim 29, wherein at least one of the LEDs further comprises a phosphor disposed so as to convert at least some of the light emitted by the at least one of the LEDs at a first wavelength to light at a second wavelength different from the first wavelength.

31. A system as recited in claim 29, wherein the first plurality of light sources comprises at least a first LED capable of emitting light of a first color and at least a second LED capable of emitting light of a second color different from the first color.

32. An optical system, comprising:

a lightguide defining a confinement direction

a first set of one or more light sources capable of generating illumination light;

a solid first light injector disposed to couple light from the one or more light sources to the lightguide, at least a first portion of the illumination light from the one or more light sources entering the first light injector along a direction having a component directed away from the lightguide, the first portion of the illumination light being totally internally reflected within the injector.

33. A system as recited in claim 32, wherein the one or more light sources emit light generally along an emission axis parallel to the confinement direction.

34. A system as recited in claim 32, wherein the first light injector has a first surface, at least a first portion of the first surface being shaped as a confinement curve for totally internally reflecting the first portion of the illumination light.

35. A system as recited in claim 34, wherein a second portion of the first surface is straight.

36. A system as recited in claim 34, wherein a second portion of the first surface is curved.

37. A system as recited in claim 34, wherein the first light injector comprises a second surface, at least a portion of the second surface being straight.

38. A system as recited in claim 34, wherein the first light injector comprises a second surface, at least a portion of the second surface being curved.

39. A system as recited in claim 32, further comprising a second set of light sources disposed proximate a second edge of the lightguide and a solid second light injector disposed to couple light from the second set of light sources into the lightguide.

40. A system as recited in claim 39, wherein the second light injector has a first surface, at least a first portion of the first surface of the second light injector being shaped as a confinement curve for confining light from the second set of light sources in the confinement direction by total internal reflection.

41. A system as recited in claim 32, wherein light is extracted from the lightguide and further comprising a display panel disposed for illumination by the light extracted from the lightguide and a controller coupled to the display panel to control an image displayed by the display panel.

42. A system as recited in claim 41, further comprising one or more light management films disposed between the lightguide and the display panel.

43. A system as recited in claim 32, wherein the one or more light sources comprises light emitting diodes (LEDs).

44. A system as recited in claim 43, wherein at least one of the LEDs further comprises a phosphor disposed so as to convert at least some of the light emitted by the at least one of the LEDs at a first wavelength to light at a second wavelength different from the first wavelength.

45. A system as recited in claim 43, wherein the first plurality of light sources comprises at least a first LED capable of emitting light of a first color and at least a second LED capable of emitting light of a second color different from the first color.