Compact biocular viewing system for an electronic display

• US 6,219,186 B1
• Filed: 08/13/1999
• Issued: 04/17/2001
• Est. Priority Date: 04/06/1998
• Status: Expired due to Term

• Current Assignee: Sherwood Partners Incorporated, Stryker Corporation
• Original Assignee: Optimize, Inc.
• Inventors: Hebert, Raymond T.
• Primary Examiner(s): Ben, Loha
• Application Number:
  US09/373,807
• Time in Patent Office: 613 Days
• Field of Search: 359/618, 359/630, 359/633, 359/464, 359/40, 359/453, 359/670, 359/583, 359/619, 359/621, 359/622, 359/462, 359/463, 348/751, 348/746, 348/53, 348/46, 345/8
• US Class Current: 359/618
• CPC Class Codes: G02B 2027/011 comprising device for correcting geometrical aberrations, distortion
• CPC Class Codes: G02B 2027/0116 comprising devices for correcting chromatic aberration
• CPC Class Codes: G02B 2027/0132 comprising binocular systems
• CPC Class Codes: G02B 2027/0136 with a single image source for both eyes
• CPC Class Codes: G02B 2027/0138 comprising image capture systems, e.g. camera
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/017 Head mounted
• 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: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 3/002 to project the image of a two-dimensional display, such as an array of light emitting or modulating elements or a CRT
• CPC Class Codes: G09G 3/003 to produce spatial visual effects

Abstract

Low-cost plastic optics allow biocular viewing of video images with a single electro-optic display device. Folded and unfolded dual off-axis configurations use collimated illumination and intermediate imaging optics to fill both eyepieces from a single display device without requiring beamsplitters. Multiple illumination schemes provide either monochrome or color, either two-dimensional or time-sequential true stereographic presentation. Light from multicolor sources is superimposed using dichroic mirrors. A display field lens proximate to the display surface collimates the illumination beam. A shaping lens provides substantially uniform illumination of the display surface. An aperture stop improves image quality by blending sub-pixel higher order spatial harmonics from the display device. Offsetting color over- and under-correction of individual optical elements provides overall chromatic correction with minimal optical complexity. Lightweight optical elements and injection-molded unitary plastic structures containing multiple optical elements reduce cost and complexity. A wireless video interface eliminates excess cabling.

Claims

1. A biocular viewing system comprising:

a single display device having a substantially planar display surface;

a first optical channel comprising;

a first light source configured to generate a first illumination beam having a axis; and

a display field lens positioned in said first illumination beam proximate to said display surface, said first illumination beam illuminating said display surface at an oblique angle; and

a second optical channel configured substantially similarly to said first optical channel, said second optical channel comprising a second light source configured to generate a second illumination beam, said second illumination beam illuminating said display surface at an oblique angle;

wherein said second optical channel and said first optical channel are mutually disposed such that said first illumination beam and said second illumination beam are angularly displaced from one another and intersect with one another at said display surface.

2. The biocular viewing system according to claim 1, wherein said display field lens is configured to substantially collimate said first illumination beam.

3. The biocular viewing system according to claim 2, wherein said display field lens is positioned in said second illumination beam proximate to said display surface, such that said display field lens is configured to substantially collimate said second illumination beam.

4. The biocular viewing system according to claim 2, wherein said first optical channel further comprises:

a first imaging beam originated by spatially modulating said first illumination beam at said display surface;

a first eyepiece lens located in said first imaging beam;

a first imaging element located in said first imaging beam between said display surface and said first eyepiece lens; and

a first intermediate image plane located in said first imaging beam between said first imaging element and said first eyepiece lens.

5. The biocular viewing system according to claim 4, wherein said first imaging element includes off-axis aspheric curvature.

6. The biocular viewing system according to claim 4, further comprising a first intermediate field lens positioned in said imaging beam proximate to said first intermediate image plane.

7. The biocular viewing system according to claim 4, further comprising an aperture stop positioned in said first beam proximate to said first imaging element.

8. The biocular viewing system according to claim 7, wherein said aperture stop is positioned between said display surface and said first imaging element.

9. The biocular viewing system according to claim 4, further comprising at least one off-axis optical element.

10. The biocular viewing system according to claim 9, wherein at least one optical element incorporates off-axis aspheric curvature.

11. The biocular viewing system according to claim 9, comprising at least one reflective optical element, thereby defining a folded optical configuration.

12. The biocular viewing system according to claim 11, wherein said display device is an optically reflective microdisplay configured to reflect and spatially modulate said first illumination beam, thereby originating said first imaging beam.

13. The biocular viewing system according to claim 12, wherein said display field lens is positioned in said first illumination beam and in said first imaging beam proximate to said display surface.

14. The biocular viewing system according to claim 4, wherein said display device is an optically transmissive microdisplay configured to transmit and spatially modulate said first illumination beam, thereby originating said first imaging beam.

15. The biocular viewing system according to claim 1, wherein said first light source comprises a light mixing cavity, said cavity including:

a plurality of light emitting diodes generating light beams of differing color; and

a diochroic mirror positioned in said light beams of differing color;

whereby said first illumination beam is emitted at said dichroic mirror.

16. The biocular viewing system according to claim 15, wherein said cavity includes a plurality of wavelength graded dichroic mirrors positioned in said light beams of differing color.

17. The biocular viewing system according to claim 15, further comprising a plurality of collimating lenses positioned between said light emitting diodes and said dichroic mirror, whereby said light beams of differing color are substantially collimated.

18. The biocular viewing system according to claim 6, further comprising a decollimating lens positioned in said first illumination beam between said dichroic mirror and said display surface.

19. The biocular viewing system according to claim 1, wherein said first optical channel includes an aspheric shaping optical element positioned in said first illumination beam between said first light source and said display surface, said aspheric shaping optical element being configured to redistribute optical energy density radially away from said axis within said first illumination beam.

20. The biocular viewing system according to claim 8, wherein said aspheric shaping optical element includes a substantially conical surface.

21. The biocular viewing system according to claim 1, wherein said display device is a liquid crystal video display.

22. A biocular viewing system comprising:

a single display device having a substantially planar display surface;

a first optical channel comprising;

a first light source configured to generate a first illumination beam having an axis, said first light source comprising a light mixing cavity including;

a plurality of light emitting diodes generating light beams of differing color; and

a diochroic mirror positioned in said light beams of differing color, whereby said first illumination beam is emitted at said dichroic mirror, such that said first illumination beam illuminates said display surface at an oblique angle; and

a second optical channel configured substantially similarly to said first optical channel comprising a second light source configured to generate a second illumination beam, said second illumination beam illuminating said display surface at an oblique angle;

wherein said second optical channel and said first optical channel are mutually disposed such that said first illumination beam and said second illumination beam are angularly displaced from one another and intersect with one another at said display surface.

23. The biocular viewing system according to claim 22, wherein said cavity includes a plurality of wavelength graded dichroic mirrors positioned in said light beams of differing color.

24. The biocular viewing system according to claim 22, further comprising a plurality of collimating lenses positioned between said light emitting diodes and said dichroic mirror, whereby said light beams of differing color are substantially collimated.

25. The biocular viewing system according to claim 24, further comprising a decollimating lens positioned in said first illumination beam between said dichroic mirror and said display surface.

26. The biocular viewing system according to claim 22, wherein said first optical channel includes an aspheric shaping optical element positioned in said first illumination beam between said first light source and said display surface, said aspheric shaping optical element being configured to redistribute optical energy density radially away from said axis within said first illumination beam.

27. The biocular viewing system according to claim 26, wherein said aspheric shaping optical element includes a substantially conical surface.

28. The biocular viewing system according to claim 22, wherein said first optical channel further comprises:

a first imaging beam originated by spatially modulating said first illumination beam at said display surface;

a first eyepiece lens located in said first imaging beam;

a first imaging element located in said first imaging beam between said display surface and said first eyepiece lens; and

a first intermediate image plane located in said first imaging beam between said first imaging element and said first eyepiece lens.

29. The biocular viewing system according to claim 28, wherein said first imaging element includes off-axis aspheric curvature.

30. The biocular viewing system according to claim 28, further comprising a first intermediate field lens positioned in said imaging beam proximate to said first intermediate image plane.

31. The biocular viewing system according to claim 28, further comprising an aperture stop positioned in said first beam proximate to said first imaging element.

32. The biocular viewing system according to claim 31, wherein said aperture stop is positioned between said display surface and said first imaging element.

33. The biocular viewing system according to claim 28, comprising at least one reflective optical element, thereby defining a folded optical configuration.

34. The biocular viewing system according to claim 33, wherein said display device is an optically reflective microdisplay configured to reflect and spatially modulate said first illumination beam, thereby originating said first imaging beam.

35. The biocular viewing system according to claim 28, wherein said display device is an optically transmissive microdisplay configured to transmit and spatially modulate said first illumination beam, thereby originating said first imaging beam.

36. The biocular viewing system according to claim 22, wherein said display device is a liquid crystal video display.

37. A biocular viewing system comprising:

a single display device having a substantially planar display surface;

a first optical channel comprising;

a first light source configured to generate a first illumination beam having an axis, such that said first illumination beam illuminates said display surface at an oblique angle; and

an aspheric shaping optical element positioned in said first illumination beam between said first light source and said display surface, said aspheric shaping optical element being configured to redistribute optical energy density radially away from said axis within said first illumination beam;

a second optical channel configured substantially similarly to said first optical channel comprising a second light source configured to generate a second illumination beam, said second illumination beam illuminating said display surface at an oblique angle;

wherein said second optical channel and said first optical channel are mutually disposed such that said first illumination beam and said second illumination beam are angularly displaced from one another and intersect with one another at said display surface.

38. The biocular viewing system according to claim 37, wherein said aspheric shaping optical element includes a substantially conical surface.

39. The biocular viewing system according to claim 37, wherein said first optical channel further comprises:

a first imaging beam originated by spatially modulating said first illumination beam at said display surface;

a first eyepiece lens located in said first imaging beam;

a first imaging element located in said first imaging beam between said display surface and said first eyepiece lens; and

a first intermediate image plane located in said first imaging beam between said first imaging element and said first eyepiece lens.

40. The biocular viewing system according to claim 39, wherein said first imaging element includes off-axis aspheric curvature.

41. The biocular viewing system according to claim 39, further comprising a first intermediate field lens positioned in said imaging beam proximate to said first intermediate image plane.

42. The biocular viewing system according to claim 39, further comprising an aperture stop positioned in said first beam proximate to said first imaging element.

43. The biocular viewing system according to claim 42, wherein said aperture stop is positioned between said display surface and said first imaging element.

44. The biocular viewing system according to claim 39, comprising at least one reflective optical element, thereby defining a folded optical configuration.

45. The biocular viewing system according to claim 44, wherein said display device is an optically reflective microdisplay configured to reflect and spatially modulate said first illumination beam, thereby originating said first imaging beam.

46. The biocular viewing system according to claim 39, wherein said display device is an optically transmissive microdisplay configured to transmit and spatially modulate said first illumination beam, thereby originating said first imaging beam.

47. The biocular viewing system according to claim 37, wherein said display device is a liquid crystal video display.

48. A method of producing a biocular video display, comprising:

generating a first illumination beam of light having an axis from a first light source in a first optical channel;

illuminating a display surface at an oblique angle relative to said first illumination beam;

collimating said first illumination beam at a display field lens proximate to said display surface such that the collimated volume of said first illumination beam is minimized;

spatially modulating said first illumination beam at said display surface, thereby originating a first imaging beam;

generating a second illumination beam of light from a second light source in a second optical channel;

illuminating said video display surface at an oblique angle with said second illumination beam;

spatially modulating said second illumination beam at said display surface, thereby originating a second imaging beam;

wherein said first and second illumination beams are mutually disposed such that said first illumination beam and said second illumination beam are angularly displaced from one another and intersect with one another at said display surface; and

wherein said first and second optical channels are configured substantially similarly.

49. The method according to claim 48, further comprising:

forming a first intermediate image of said display surface at a first intermediate image plane in said first imaging beam using a first imaging element following said display surface; and

directing said first imaging beam from said first intermediate image plane to fill a first eyepiece lens.

50. The method according to claim 49, wherein at least one optical element selected from the group consisting of said display field lens and said first imaging element applies off-axis aspheric correction to remove off-axis image distortion in said first imaging beam due to said oblique illumination of said display surface by said first illumination beam.

51. The method according to claim 49, wherein said directing is performed using an intermediate field lens positioned proximate to said first intermediate image plane.

52. The method according to claim 51, wherein at least one optical element selected from said display field lens, said first imaging element, said intermediate field lens, and said first eyepiece lens is configured for color overcorrection.

53. The method according to claim 51, wherein at least one optical element selected from said display field lens, said first imaging element, said intermediate field lens, and said first eyepiece lens is configured for color undercorrection.

54. The method according to claim 49, further comprising positioning an aperture stop in said first imaging beam proximate to said first imaging element, whereby said aperture stop improves display contrast by blocking glare from stray and scattered light.

55. The method according to claim 49, wherein said first optical channel includes at least one reflective optical element incorporating total internal reflection.

56. The method according to claim 49, wherein said first optical channel includes at least one reflective optical element, thereby defining a folded optical configuration.

57. The method according to claim 56, wherein said display device is an optically reflective microdisplay configured to reflect and spatially modulate said first illumination beam, thereby originating said first imaging beam.

58. The method according to claim 57, wherein said display field lens is positioned in said first illumination beam and in said first imaging beam proximate to said display surface.

59. The method according to claim 49, wherein said display device is an optically transmissive microdisplay configured to transmit and spatially modulate said first illumination beam, thereby generating said first imaging beam.

60. The method according to claim 48, wherein said generating of said first illumination beam further comprises:

generating light beams of differing color from a plurality of light emitting diodes; and

combining said light beams of differing color at a diochroic mirror;

whereby said first illumination beam exits at said dichroic mirror.

61. The method according to claim 60, wherein said light beams of differing color are combined at a plurality of wavelength graded dichroic mirrors.

62. The method according to claim 60, wherein a plurality of collimating lenses is positioned between said light emitting diodes and said dichroic mirror, whereby said light beams of differing color are substantially collimated.

63. The method according to claim 62, wherein a decollimating lens is positioned in said first illumination beam between said dichroic mirror and said display surface.

64. The method according to claim 48, wherein said first illumination beam is shaped by an aspheric shaping optical element positioned in said first illumination beam between said first light source and said display surface, said aspheric shaping optical element being configured to redistribute optical energy density radially away from said axis within said first illumination beam.

65. The method according to claim 48, wherein said display device is a liquid crystal video display.

66. The method according to claim 48, further comprising collimating said second illumination beam at said display field lens.