Systems and methods for providing compact illumination in head mounted displays

• US 7,843,642 B2
• Filed: 05/04/2006
• Issued: 11/30/2010
• Est. Priority Date: 05/04/2006
• Status: Active Grant

• Current Assignee: University of Central Florida Research Foundation Inc. (State University System of Florida)
• Original Assignee: University of Central Florida Research Foundation Inc. (State University System of Florida)
• Inventors: Rolland, Jannick, Ha, Yonggang, Shaoulov, Vesselin
• Primary Examiner(s): Sugarman, Scott J
• Assistant Examiner(s): PINKNEY, DAWAYNE
• Application Number:
  US11/417,874
• Publication Number:
  US 20070258049A1
• Time in Patent Office: 1,671 Days
• Field of Search: 359/129, 359/496, 359/618, 359/631, 359/629, 359/634, 359/636, 359638-640, 359/831, 359833-834, 359/630, 353/31, 353/34, 353/81, 451/28, 451/41
• US Class Current: 359/634
• CPC Class Codes: G03B 21/006 using LCD's

Abstract

Disclosed are systems and methods for providing illumination in a head mounted display. In one embodiment a method includes emitting light from a plurality of sources at a plurality of wavelengths and transmitting the light from the plurality of sources to a first device. The method further includes combining the light, utilizing the first device, from the plurality of sources into a combined light signal and creating telecentricity in the combined light signal. The method also includes receiving a telecentric light signal on a display surface. In one embodiment the system includes a light source, a hybrid reflective structure configured as a truncated pyramid and further configured to transmit light emitted by the light source and an optics device configured to create telecentricity in light that was transmitted through the hybrid reflective structure to a display surface.

Claims

1. A system for providing illumination in a head mounted display, comprising:

a plurality of light emitting diodes;

a color combining device configured to receive light emitted by the light emitting diodes, to combine the received light, and to transmit a combined light signal;

a hybrid reflective structure positioned between each light emitting diode and the color combining device, each hybrid reflective structure being configured to transmit the light emitted by an adjacent light emitting diode to the color combining device; and

a telecentric optics device configured to receive the combined light signal, to collimate the combined light signal, and transmit a collimated light signal to a display surface.

2. The system of claim 1, wherein the plurality of light emitting diodes comprise:

a red light emitting diode;

a green light emitting diode; and

a blue light emitting diode.

3. The system of claim 1, wherein each of the plurality of hybrid reflective structures comprises a monolithic structure formed as a truncated pyramid.

4. The system of claim 3, wherein the truncated pyramid comprises a shape selected from the group consisting of:

symmetric or anamorphic.

5. The system of claim 1, wherein each of the plurality of hybrid reflective structures comprises a monolithic structure formed as a cone.

6. The system of claim 5, wherein the cone comprises a shape selected from the group consisting of:

symmetric or anamorphic.

7. The system of claim 1, wherein each hybrid reflective structure comprises:

a receiving surface coupled with its adjacent light emitting diode; and

a transmitting surface coupled to a receiving surface of the color combining device; and

a plurality of distinct side surfaces that extend between the receiving surface and the transmitting surface.

8. The system of claim 7, wherein each hybrid reflective structure further comprises:

a reflective coating on the plurality of distinct side surfaces; and

an anti-reflective coating on the receiving surface.

9. The system of claim 7, wherein the receiving surface is configured in a substantially square geometry and wherein the transmitting surface is configured in a substantially rectangular geometry.

10. The system of claim 7, wherein the receiving surface is preferably dimensioned as a 1 mm by 1 mm square.

11. The system of claim 7, wherein the transmitting surface is preferably dimensioned as a 2 mm by 2.5 mm rectangle.

12. The system of claim 1, wherein the color combining device comprises:

a plurality of light receiving surfaces configured to receive light from the plurality of hybrid reflective structures;

a light transmitting surface configured to transmit the combined light signal, wherein the light transmitting surface is substantially parallel to a first light receiving surface of the plurality of light receiving surfaces;

a first internal reflective surface configured diagonally between a second light receiving surface and a third light receiving surface, wherein the second light receiving surface and the third light receiving surface are each perpendicular to the first light receiving surface; and

a second internal reflective surface configured diagonally between the second light receiving surface and the third light receiving surface and oriented substantially perpendicular to the first internal reflective surface.

13. The system of claim 12, wherein the first internal reflective surface reflects light from the second light receiving surface to the light transmitting surface and wherein the second internal reflective surface reflects light from the third light receiving surface to the light transmitting surface.

14. The system of claim 12, wherein the first internal reflective surface is configured to reflect a first wavelength of light corresponding to light received by the second receiving surface and wherein the second internal reflective surface is configured to reflect a second wavelength of light corresponding to light received by the third receiving surface.

15. The system of claim 1, wherein the telecentric optics device comprises a Fresnel lens having a focal point between a first light receiving surface of the color combining device and a transmitting surface of the color combining device.

16. The system of claim 1, further comprising a beam splitting optical device configured to split the light signal reflected from the display surface.

17. The system of claim 1, further comprising means for bonding the plurality of hybrid reflective structures to the color combining device.

18. The system of claim 7, wherein the receiving surface of each hybrid reflective structure has a smaller surface area than the transmitting surface.

19. The system of claim 7, wherein the transmitting surface of each hybrid reflective structure is cemented or glued to the color combining device.

20. The system of claim 7, wherein each hybrid reflective structure is shaped as a four-sided truncated pyramid having the receiving surface as a top and the transmitting surface as a base.

21. The system of claim 1, wherein each hybrid reflective structure is composed of a low-absorption glass or plastic.

22. The system of claim 1, wherein each hybrid reflective structure is hollow.

23. The system of claim 1, wherein the telecentric optics device is focused on a receiving surface of the color combining device at which light emitted by one of the light emitting diodes is received.

24. A method for providing illumination in a head mounted display, comprising:

emitting light from a plurality of sources at a plurality of wavelengths;

transmitting the light emitted by each light source to a color combining device using a hybrid reflective structure having a receiving surface and an opposed transmitting surface;

combining the light, using the color combining device, into a combined light signal;

collimating the combined light signal to create a collimated combined light signal; and

receiving the collimated combined light signal on a display surface.

25. The method of claim 24, further comprising reflecting a display light signal from the display surface in a substantially nonparallel direction relative to the collimated combined light signal received by the display surface.

26. The method of claim 25, wherein a reflected display signal is received by a beam splitting optical device.

27. The method of claim 24, wherein the plurality of wavelengths comprise:

a first wavelength in the range between 449 and 491 nanometers;

a second wavelength in the range between 509 and 551 nanometers; and

a third wavelength in the range between 606 and 648 nanometers.

28. The method of claim 24, wherein each hybrid reflective structure is configured as a truncated pyramid.

29. The method of claim 24, wherein the hybrid reflective structures further have side surfaces extending from the receiving surface to the transmitting surface, and wherein transmitting the light comprises reflecting the light off of the side surfaces.

30. A system for providing illumination in a head mounted display, comprising:

light sources that emit light;

a color combiner that combines the light emitted by the light sources;

reflective structures configured to transmit the light emitted by the light sources to the color combiner; and

an optics device configured to collimate a combined light signal transmitted by the color combiner and transmit the collimated combined light signal to a display surface.

31. The system of claim 30, wherein the light sources comprise light emitting diodes.

32. The system of claim 31, wherein the light emitting diodes comprise:

a red light emitting diode;

a green light emitting diode; and

a blue light emitting diode.

33. The system of claim 30, wherein the color combiner comprises:

light receiving surfaces configured to receive light from the reflective structures;

a light transmitting surface configured to transmit the combined light signal;

a first internal reflective surface configured diagonally within the color combiner; and

a second internal reflective surface configured diagonally within the color combiner.

34. The system of claim 33, wherein the first internal reflective surface reflects light from a first light receiving surface of the color combiner to the light transmitting surface and wherein the second internal reflective surface reflects light from a second light receiving surface to the light transmitting surface.

35. The system of claim 33, wherein the first internal reflective surface is configured to reflect a first wavelength of light and wherein the second internal reflective surface is configured to reflect a second wavelength of light.

36. The system of claim 30, wherein each reflective structure comprises a monolithic structure formed as a truncated pyramid.

37. The system of claim 30, wherein each reflective structure comprises a monolithic structure formed as a cone.

38. The system of claim 30, wherein each reflective structure comprises:

a receiving surface coupled to an adjacent light source;

a transmitting surface coupled to a receiving surface of the color combiner; and

a plurality of distinct side surfaces that extend between the receiving surface of the reflective structure and the transmitting surface of the reflective structure.

39. The system of claim 38, wherein each reflective structure further comprises:

a reflective coating on the plurality of distinct side surfaces; and

an anti-reflective coating on the receiving surface of the reflective structure.

40. The system of claim 30, wherein the optics device comprises a telecentric optics device.

41. The system of claim 40, wherein the telecentric optics device comprises a Fresnel lens having a focal point between a light receiving surface of the color combiner and a transmitting surface of the color combiner.

42. The system of claim 30, further comprising a beam splitting optical device configured to split the light signal reflected from the display surface.

43. A system for providing illumination in a head mounted display, comprising:

a plurality of light emitting diodes;

a plurality of hybrid reflective structures configured to transmit light that is received from the plurality of light emitting diodes, each hybrid reflective structure comprising a monolithic structure formed as a truncated pyramid comprising;

a plurality of side surfaces, wherein the each of the plurality of side surfaces is adjacent and joined to two other of the plurality of side surfaces,

a receiving surface adjacent the plurality of side surfaces, wherein the receiving surface is configured to be adjacent one of the plurality of light emitting diodes, and

a transmitting surface adjacent the plurality of side surfaces, wherein the transmitting surface is substantially parallel to the receiving surface, and wherein the transmitting surface is configured to be adjacent a receiving surface on the color combining device,

wherein the receiving surface comprises a first area, wherein the transmitting surface comprises a second area, and wherein the second area is greater than the first area;

a color combining device configured to receive light transmitted from the plurality of hybrid reflective structures, the color combining device further being configured to transmit a combined light signal; and

a telecentric optics device configured to receive the combined light signal and transmit a telecentric light signal to a display surface.

44. The system of claim 43, further comprising:

a reflective coating on the plurality of side surfaces; and

an anti-reflective coating on the receiving surface.

45. The system of claim 43, wherein the receiving surface is configured in a substantially square geometry and wherein the transmitting surface is configured in a substantially rectangular geometry.

46. The system of claim 43, wherein the receiving surface is preferably dimensioned as a 1 mm by 1 mm square.

47. The system of claim 43, wherein the transmitting surface is preferably dimensioned as a 2 mm by 2.5 mm rectangle.