NEAR EYE DISPLAY SYSTEM

• US 20090147331A1
• Filed: 08/24/2006
• Published: 06/11/2009
• Est. Priority Date: 09/12/2005
• Status: Active Grant

• Current Assignee: Elbit Systems Limited
• Original Assignee: Elbit Systems Limited
• Inventors: Ashkenazi, Asaf
• Granted Patent: US 8,079,713 B2
• Time in Patent Office: Days
• US Class Current: 359/13
• CPC Class Codes: G02B 2027/011 comprising device for correcting geometrical aberrations, distortion
• CPC Class Codes: G02B 2027/0125 Field-of-view increase by wavefront division
• CPC Class Codes: G02B 2027/0174 holographic
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 5/30 Polarising elements light-modulating devices with active elements G02F1/00
• CPC Class Codes: G02B 5/32 Holograms used as optical elements

Abstract

A near eye image display system includes an image projector, a beam combiner assembly, and an optical assembly, optically coupled between the image projector and the beam combiner assembly The image projector projects a display image toward an optical pathway, the optical pathway intersecting a viewing axis, the viewing axis extending from the eye of a user to an ambient scene The beam combiner assembly includes a plurality of beam combiners optically cascaded along the optical pathway, each of the beam combiners being disposed diagonally to the optical pathway and diagonally to the viewing axis Each of the beam combiners is arranged such that for each two adjacent beam combiners, the first of the adjacent beam combiners is optically located between the second of the adjacent beam combiners and the image projector The geometrical projection of the second beam combiner onto a first plane perpendicular to the optical pathway, is subsumed within the geometrical projection of the first beam combiner onto the first plane Each of the beam combiners is further arranged such that the partial geometric projection of each of the beam combiners onto a second plane perpendicular to the viewing axis forms a continuous geometric projection, the optical assembly directing display light of the display image from the image projector toward the beam combiner assembly along the optical pathway Each of the beam combiners reflects the display light toward the eye, and further directs ambient light emerging from the ambient scene toward the eye, thereby superimposing the display image onto the ambient scene.

Claims

1. Near eye image display system comprising:

an image projector, projecting a display image toward an optical pathway, said optical pathway intersecting a viewing axis, said viewing axis extending from the eye of a user to an ambient scene;

a beam combiner assembly comprising a plurality of beam combiners, said beam combiners optically cascaded along said optical pathway, each of said beam combiners being disposed diagonally to said optical pathway and diagonally to said viewing axis;

each of said beam combiners arranged such that for each two adjacent said beam combiners, the first of said adjacent beam combiners being optically located between the second of said adjacent beam combiners and said image projector, the geometrical projection of said second beam combiner onto a first plane being perpendicular to said optical pathway, is subsumed within the geometrical projection of said first beam combiner onto said first plane,

each of said beam combiners further arranged such that the partial geometric projection of each of said beam combiners onto a second plane being perpendicular to said viewing axis, forms a continuous geometric projection; and

an optical assembly, optically coupled between said image projector and said beam combiner assembly, said optical assembly directing display light of said display image from said image projector toward said beam combiner assembly along said optical pathway; and

a double prism assembly optically coupled between said image projector and said optical assembly, said double prism assembly including a first prism and a second prism, each said first prism and said second prism having at least a first surface, a second surface and a third surface, wherein said first surface, said second surface and said third surface are geometrically extendable to form a triangle, each said first prism and said second prism being made of transparent material,

wherein said first surface of said first prism is coupled to said image projector, said first prism receiving said display light from said image projector, at a substantially perpendicular direction to said first surface of said first prism,

wherein said first surface of said second prism is coupled to said optical assembly, said second prism directing said display light toward said optical assembly, at a substantially perpendicular direction to said first surface of said second prism,

wherein for each of said first prism and said second prism, the angle between said third surface and said first surface is substantially 67°

30′

$\left(\frac{3<br><br>\mathrm{\pi <br><br>}}{8}\right),$

the angle between said third surface and said second surface is substantially 67°

30′

$\left(\frac{3<br><br>\mathrm{\pi <br><br>}}{8}\right),$

and the angle between said first surface and said second surface substantially 45°

$\left(\frac{\mathrm{\pi <br><br>}}{4}\right),$

wherein said second surface of said first prism is disposed adjacent to said second surface of said second prism, with a transparent medium there between, wherein the ratio between the refractive index of said transparent material and the refractive index of said transparent medium is such that said ratio produces total internal reflection of a first light beam, incident on said second surface of said first prism, said first light beam arriving at said second surface of said first prism at a substantially perpendicular direction to said first surface of said first prism, said ratio further producing total internal reflection of a second light beam incident on said second surface of said second prism, said second light beam exiting said second surface of said second prism at a substantially perpendicular direction to said first surface of said second prism,

wherein for each of said first prism and said second prism, said third surface is optically reflective, providing total internal reflection,

wherein said double prism assembly directs said display light toward said optical assembly along said optical pathway, and

wherein each of said beam combiners reflects said display light toward said eye, and wherein each of said beam combiners further directs ambient light emerging from said ambient scene toward said eye, thereby superimposing said display image onto said ambient scene.

3. The system according to claim 1, wherein said optically reflective third surface of each of said first prism and said second prism is coated with a reflective coating.

4. The system according to claim 1, wherein a reflective medium is positioned adjacent to said optically reflective third surface of each of said first prism and said second prism includes.

5. The system according to claim 1, wherein said display light enters said double prism assembly via said first surface of said first prism, at a substantially perpendicular direction to said first surface of said first prism, toward said second surface of said first prism,

said second surface of said first prism reflects said display light toward said third surface of said first prism, said third surface of said first prism reflects said display light toward said first surface of said first prism, said first surface of said first prism reflects said display light toward said first surface of said second prism, said first surface of said second prism reflects said display light toward said third surface of said second prism,

said third surface of said second prism reflects said display light toward said second surface of said second prism, and said display light exits said double prism assembly via said first surface of said second prism at a substantially perpendicular direction to said first surface of said second prism.

6. The system according to claim 1, further comprising a field flattener optically coupled with said image projector,

said field flattener flattens the image plane of said display image projected by said image projector.

7. The system according to claim 6, further comprising a focus adjustment mechanism coupled with said image projector and with said field flattener,

said focus adjustment mechanism adjusting the focus of said display image projected by said image projector.

8. The system according to claim 7, wherein said focus adjustment mechanism adjusts the focus of said display image projected by said image projector so that said display image appears at optical infinity.

9. The system according to claim 7, wherein said focus adjustment mechanism adjusts the focus of said display image projected by said image projector so that said display image appears nearby.

10. The system according to claim 1, further comprising an electronic interface coupled with said image projector,

said electronic interface interfacing between said display system and external electronic components.

11. The system according to claim 1, wherein said image projector is selected from the list consisting of:

a transmissive display;

a reflective display; and

an emissive display.

12. The system according to claim 1, wherein said image projector receives an image representation from an external source, and projects an image in accordance with said image representation.

13. The system according to claim 1, wherein said display image is electronically pre-distorted in accordance with optical properties of said system.

14. The system according to claim 1, wherein said beam combiners are straight lengthwise.

15. The system according to claim 1, wherein said beam combiners are curved lengthwise.

16. The system according to claim 1, wherein said beam combiners are holographic.

17. The system according to claim 16, wherein said beam combiners transmit only certain wavelengths of light.

18. The system according to claim 1, wherein said beam combiners are polarized.

19. The system according to claim 18, wherein said image projector generates polarized light, and wherein said beam combiners transmit only one type of polarization.

20. The system according to claim 1, wherein each of said beam combiners have different levels of transmittance or reflectance.

21. The system according to claim 1, wherein the ratio between the amount of said display light and the amount of said ambient light reaching said eye, is adjustable.

22. The system according to claim 1, further comprising an attachment mechanism coupled with said projector,

said attachment mechanism attaching and detaching said system to an external device,

said attachment mechanism further interfacing between said system and external electronic components.

23. The system according to claim 22, wherein said system is mounted via said attachment mechanism onto eyewear.

24. The system according to claim 23, wherein said eyewear is selected from the list consisting of:

eyeglasses;

spectacles; and

goggles.

25. The system according to claim 22, wherein said system is mounted via said attachment mechanism onto head gear.

26. The system according to claim 25, wherein said head gear is selected from the list consisting of:

a mask; and

a helmet.

27. The system according to claim 22, wherein said attachment mechanism is selected from the list consisting of:

an electromechanical attachment mechanism;

an opto-mechanical attachment mechanism;

an electro-opto-mechanical attachment mechanism; and

a wireless-based attachment mechanism.

28. The system according to claim 1, wherein said system is inside housing comprising protective windows.

29. The system according to claim 27, wherein said protective windows is selected from the list consisting of:

transparent;

partially transparent;

variably transparent;

electronically adjustable variably transparent; and

polarized.

30. The system according to claim 1, wherein said optical pathway is substantially perpendicular to said viewing axis.

31. The system according to claim 1, wherein said viewing axis is at an angle with respect to said optical pathway.

2. (canceled)

32. Near eye image display system comprising

an image projector, projecting a display image toward an optical pathway, said optical pathway intersecting a viewing axis, said viewing axis extending from the eye of a user to an ambient scene;

a beam combiner assembly comprising a plurality of beam combiners, said beam combiners optically cascaded along said optical pathway, each of said beam combiners being disposed diagonally to said optical pathway and diagonally to said viewing axis,

each of said beam combiners arranged such that for each two adjacent said beam combiners, the first of said adjacent beam combiners being optically located between the second of said adjacent beam combiners and said image projector, the geometrical projection of said second beam combiner onto a first plane being perpendicular to said optical pathway, is subsumed within the geometrical projection of said first beam combiner onto said first plane,

each of said beam combiners further arranged such that the partial geometric projection of each of said beam combiners onto a second plane being perpendicular to said viewing axis, forms a continuous geometric projection;

an optical assembly, optically coupled between said image projector and said beam combiner assembly, said optical assembly directing display light of said display image from said image projector toward said beam combiner assembly along said optical pathway; and

a prism, optically coupled between said image projector and said optical assembly,

said prism having at least a first surface, a second surface and a third surface, wherein

said first surface, said second surface and said third surface are geometrically extendable to form a triangle, said prism being made of transparent material,

wherein the angle between said third surface and said first surface is substantially 67°

30′

$\left(\frac{3<br><br>\mathrm{\pi <br><br>}}{8}\right),$

the angle between said third surface and said second surface is substantially 67°

30′

$\left(\frac{3<br><br>\mathrm{\pi <br><br>}}{8}\right),$

and the angle between said first surface and said second surface substantially 45°

$\left(\frac{\mathrm{\pi <br><br>}}{4}\right),$

wherein said third surface is optically reflective, providing total internal reflection,

wherein said first surface of said prism is coupled to said image projector, said prism receiving said display light from said image projector, at a substantially perpendicular direction to said first surface of said prism; and

wherein said second surface of said prism is coupled to said optical assembly, said display light is reflected by said second surface of said prism toward said third surface of said prism, said display light is reflected by said third surface of said prism toward said first surface of said prism, said display light is reflected by said first surface of said prism toward said second surface of said prism at a substantially perpendicular direction to said second surface of said prism, said prism directing said display light toward said optical assembly.

36. The system according to claim 32, wherein said optically reflective third surface of said prism is coated with a reflective coating.

37. The system according to claim 32, wherein a reflective medium is positioned adjacent to said optically reflective third surface of said prism.

38. The system according to claim 32, further comprising a field flattener optically coupled with said image projector,

said field flattener flattens the image plane of said display image projected by said image projector.

39. The system according to claim 32, further comprising an electronic interface coupled with said image projector,

Said electronic interface interfacing between said display systems and external electronic components.

40. The system according to claim 32, wherein said image projector is selected from the list consisting of:

a transmissive display;

a reflective display; and

an emissive display.

41. The system according to claim 32, wherein said image projector receives an image representation from an external source, and projects an image in accordance with said image representation

42. The system according to claim 32, wherein said display image is electronically pre-distorted in accordance with optical properties of said system.

43. The system according to claim 32, wherein said beam combiners are straight lengthwise.

44. The system according to claim 32, wherein said beam combiners are curved lengthwise.

45. The system according to claim 32, wherein said beam combiners are holographic.

46. The system according to claim 32, wherein said beam combiners are polarized.

47. The system according to claim 32, wherein each of said beam combiners have different levels of transmittance or reflectance.

48. The system according to claim 32, wherein the ratio between the amount of said display light and the amount of said ambient light reaching said eye, is adjustable.

49. The system according to claim 32, further comprising an attachment mechanism coupled with said projector,

said attachment mechanism attaching and detaching said system to an external device, said attachment mechanism further interfacing between said system and external electronic components.

50. The system according to claim 32 wherein said system is inside housing comprising protective windows.

51. The system according to claim 32, wherein said optical pathway is substantially perpendicular to said viewing axis.

52. The system according to claim 32, wherein said viewing axis is at an angle with respect to said optical pathway.

33. A double prism assembly, for folding the light rays from a display image, said double prism assembly comprising a first prism and a second prism, each said first prism and said second prism having at least a first surface, a second surface and a third surface, wherein said first surface, said second surface and said third surface are geometrically extendable to form a triangle, each said first prism and said second prism being made of transparent material, said double prism assembly reflecting said light rays within said first prism and said second prism in a controlled manner,

wherein said first surface of said first prism is coupled to said image projector, said first prism receiving said display light from said image projector, at a substantially perpendicular direction to said first surface of said first prism,

wherein said first surface of said second prism is coupled to said optical assembly, said second prism directing said display light toward said optical assembly, at a substantially perpendicular direction to said first surface of said second prism,

wherein for each of said first prism and said second prism, the angle between said third surface and said first surface is substantially 67°

30′

$\left(\frac{3<br><br>\mathrm{\pi <br><br>}}{8}\right),$

the angle between said third surface and said second surface is substantially 67°

30′

$\left(\frac{3<br><br>\mathrm{\pi <br><br>}}{8}\right),$

and the angle between said first surface and said second surfacesubstantially 45°

$\left(\frac{\mathrm{\pi <br><br>}}{4}\right),$

wherein said second surface of said first prism is disposed adjacent to said second surface of said second prism, with a transparent medium there between, wherein the ratio between the refractive index of said transparent material and the refractive index of said transparent medium is such that said ratio produces total internal reflection of a first light beam, incident on said second surface of said first prism, said first light beam arriving at said second surface of said first prism at a substantially perpendicular direction to said first surface of said first prism, said ratio further producing total internal reflection of a second light beam incident on said second surface of said second prism, said second light beam exiting said second surface of said second prism at a substantially perpendicular direction to said first surface of said second prism,

wherein for each of said first prism and said second prism, said third surface is optically reflective, providing total internal reflection.

34-35. -35. (canceled)