Display panel having dual directional diffusion

• US 20040071417A1
• Filed: 10/09/2002
• Published: 04/15/2004
• Est. Priority Date: 10/09/2002
• Status: Active Grant

• Current Assignee: SCRAM Technologies, Inc
• Original Assignee: SCRAM Technologies, Inc
• Inventors: Veligdan, James T.
• Granted Patent: US 6,999,665 B2
• Time in Patent Office: Days
• US Class Current: 385/120
• CPC Class Codes: G02B 6/08 with fibre bundle in form of plate

Abstract

An optical panel includes a plurality of stacked optical waveguides bound by black cladding to collectively form an inlet face and an opposite display screen. An inlet diffuser has an inlet surface, and an opposite outlet surface adjoining the inlet face of the waveguides. Asymmetric diffusion of image light is effected by the inlet diffuser for increasing field of view, with ambient light being absorbed through the display screen for increasing contrast. Alternatively, an outlet diffuser may be provided at the display screen to complement the inlet diffuser by differently diffusing the image light spatially at the display screen.

Claims

1. An optical panel for displaying an image, comprising:

a plurality of stacked optical waveguides, each having a first end and a second end, wherein an inlet face is defined by the plurality of first ends, and wherein an outlet face is defined by the plurality of second ends; and

an inlet diffuser provided at the inlet face of the waveguides, wherein the inlet diffuser diffuses light that forms the image asymmetrically.

2. A panel according to claim 1, wherein the inlet diffuser is configured for diffusing the light both in a first direction and in a second direction into the waveguides, and wherein the second direction is perpendicular to the first direction.

3. A panel according to claim 2, wherein the inlet diffuser provides diffusion of the light in the first direction in an amount greater than diffusion of the light in the second direction.

4. A panel according to claim 3, wherein the first direction is the horizontal direction, wherein the second direction is the vertical direction, and wherein each waveguide extends horizontally along a width of the panel.

5. A panel according to claim 2, wherein each of the waveguides includes a transmissive core having a first index of refraction, each transmissive core bound by cladding having a second index of refraction being less than the first index of refraction, and wherein the waveguides have an acceptance angle determined collectively by the first and second indices of refraction.

6. A panel according to claim 5, wherein the inlet diffuser has a diffusion cone angle in the second direction being less than or substantially equal to the acceptance angle of the waveguides.

7. A panel according to claim 2, wherein the inlet diffuser comprises diffusion elements in the form of concentric ellipses.

8. A panel according to claim 1, wherein the inlet diffuser comprises diffusion elements in the form of parallel lines which effect diffusion in substantially only one direction.

9. A panel according to claim 1, wherein the inlet diffuser comprises diffusion elements in the form of lenticular lenses having gain in substantially only one direction.

10. A panel according to claim 2 further comprising a coupler provided at an inlet surface of the inlet diffuser for redirecting the light through the inlet diffuser into the waveguides.

11. A panel according to claim 10, wherein the coupler comprises Fresnel prismatic grooves.

12. A panel according to claim 10, wherein the coupler comprises a transmissive right angle film.

13. A panel according to claim 5, wherein the cladding comprises a substantially black material.

14. A panel according to claim 1 further comprising an outlet diffuser provided at the outlet face, wherein the outlet diffuser complements the inlet diffuser by differently diffusing the light spatially at the outlet face.

15. A panel according to claim 14, wherein the inlet diffuser is configured for diffusing the light mostly in a first direction into the waveguides, wherein the outlet diffuser is configured for diffusing the light mostly in a second direction, and wherein the second direction is perpendicular to the first direction.

16. A panel according to claim 15, wherein the inlet diffuser provides diffusion of the light in the first direction in an amount greater than diffusion of the light in the second direction provided by the outlet diffuser.

17. A panel according to claim 16, wherein the first direction is the horizontal direction, wherein the second direction is the vertical direction, and wherein each waveguide extends horizontally along a width of the panel.

18. A panel according to claim 15, wherein each of the waveguides includes a transmissive core having a first index of refraction, each transmissive core bound by cladding having a second index of refraction being less than the first index of refraction, and wherein the waveguides have an acceptance angle determined collectively by the first and second indices of refraction.

19. A panel according to claim 15, wherein the inlet diffuser is configured to diffuse the light in the first direction at a cone angle greater than a cone angle of diffusion of the light in the second direction from the outlet diffuser.

20. A panel according to claim 18, wherein the inlet diffuser has a diffusion cone angle in the second direction being less than or substantially equal to the acceptance angle of the waveguides.

21. A panel according to claim 15, wherein the inlet diffuser comprises diffusion elements in the form of parallel lines which effect diffusion in substantially only the first direction.

22. A panel according to claim 15, wherein the inlet diffuser comprises diffusion elements in the form of lenticular lenses having gain in substantially only the first direction.

23. A panel according to claim 15, wherein the outlet diffuser comprises diffusion elements in the form of parallel lines which effect diffusion in substantially only the second direction.

24. A panel according to claim 15, wherein the outlet diffuser comprises diffusion elements in the form of lenticular lenses having gain in substantially only the second direction.

25. A panel according to claim 14, wherein the inlet diffuser is configured for diffusing the light both in a first direction and in a second direction into the waveguides, wherein the outlet diffuser is configured for diffusing the light mostly in the second direction, and wherein the second direction is perpendicular to the first direction.

26. A panel according to claim 25, wherein the inlet diffuser provides diffusion of the light in the first direction in an amount greater than diffusion of the light in the second direction.

27. A panel according to claim 26, wherein the first direction is the horizontal direction, wherein the second direction is the vertical direction, and wherein each waveguide extends horizontally along a width of the panel.

28. A panel according to claim 25, wherein each of the waveguides includes a transmissive core having a first index of refraction, each transmissive core bound by cladding having a second index of refraction being less than the first index of refraction, and wherein the waveguides have an acceptance angle determined collectively by the first and second indices of refraction.

29. A panel according to claim 25, wherein the inlet diffuser is configured to diffuse the light in the first direction at a cone angle greater than a cone angle of diffusion of the light in the second direction.

30. A panel according to claim 25, wherein the inlet diffuser is configured to diffuse the light in the first direction at a cone angle greater than a cone angle of diffusion of the light in the second direction from the outlet diffuser.

31. A panel according to claim 28, wherein the inlet diffuser has a diffusion cone angle in the second direction being less than or substantially equal to the acceptance angle of the waveguides.

32. A panel according to claim 25, wherein the inlet diffuser comprises diffusion elements in the form of concentric ellipses.

33. A panel according to claim 14 further comprising a coupler provided at an inlet surface of the inlet diffuser for redirecting the light through the inlet diffuser into the waveguides.

34. A panel according to claim 33, wherein the coupler comprises Fresnel prismatic grooves.

35. A panel according to claim 33, wherein the coupler comprises a transmissive right angle film.

36. A panel according to claim 18, wherein the cladding comprises a substantially black material.

37. A panel according to claim 28, wherein the cladding comprises a substantially black material.

38. A panel according to claim 1, wherein the waveguides are planar.

39. A panel according to claim 1, wherein the inlet face is substantially parallel to the outlet face.