Method and system for display resolution multiplication

• US 6,421,109 B1
• Filed: 10/15/1999
• Issued: 07/16/2002
• Est. Priority Date: 10/16/1998
• Status: Expired due to Fees

• Current Assignee: Hoya Corporation
• Original Assignee: DigiLens Inc
• Inventors: Popovich, Milan M.
• Primary Examiner(s): Parker, Kenneth
• Application Number:
  US09/419,016
• Time in Patent Office: 1,005 Days
• Field of Search: 349/15, 349/201, 349/202, 359/15, 359/17, 359/315-316, 359/462, 359/298, 345/6, 348/54, 348/56, 348/756
• US Class Current: 349/202
• CPC Class Codes: G02B 5/32 Holograms used as optical elements
• CPC Class Codes: G03H 1/26 Processes or apparatus specially adapted to produce multiple sub- holograms or to obtain images from them, e.g. multicolour technique
• CPC Class Codes: H04N 5/72 Modifying the appearance of television pictures by optical filters or diffusing screens
• CPC Class Codes: H04N 9/30 using solid-state colour display devices

Abstract

Disclosed is an optical display system and a method for increasing the resolution of an display device. The optical display system includes a display device which includes a pixel and a holographic optical element positioned in front of the pixel. The holographic optical element is configured to diffract a portion of the incident light from the pixel toward a user of the display system such that two or more pixels may be perceived by the user.

Claims

1. An apparatus comprising:

a display device comprising a plurality of light emitting pixels, wherein a first pixel is configured to emit a first and second light in first and second directions, respectively, wherein the first and second directions define a non-zero angle therebetween;

a first optical element comprising first, second, and third holograms each one of which is configured to operate in an active state or an inactive state, wherein the first hologram is configured to diffract red bandwidth light when operating in the active state, wherein the first hologram is configured to transmit red bandwidth light without diffraction when operating in the inactive state, wherein the second hologram is configured to diffract green bandwidth light when operating in the active state, wherein the second hologram is configured to transmit green bandwidth light without diffraction when operating in the inactive state, and wherein the third hologram is configured to diffract blue bandwidth light when operating in the active state, wherein the third hologram is configured to transmit blue bandwidth light without diffraction when operating in the inactive state;

wherein the first optical element is positioned to receive the first light, wherein the first optical element is configured to diffract the first light, wherein the diffracted first light emerges from the first optical element in a direction substantially parallel to the second direction.

2. The apparatus of claim 1 wherein the first optical element comprises a first holographic recording medium, wherein the first hologram is recorded in the first holographic recording medium.

3. The apparatus of claim 1 wherein the first optical element comprises a first holographic recording medium, wherein the first holographic recording medium comprises liquid crystal elements, and wherein the first hologram is recorded in the first holographic recording medium.

4. The apparatus of claim 3 wherein the first holographic recording medium comprises a photo-polymer.

5. The apparatus of claim 1 wherein the first optical element comprises a first holographic recording medium, wherein the first hologram is recorded in the first holographic recording medium, wherein the first hologram is formed during a hologram recording process whereby a polymer dispersed liquid crystal material undergoes phase separation to create regions populated by liquid crystal droplets and to create regions of clear photopolymer interspersed by regions populated by liquid crystal droplets.

6. The apparatus of claim 1 wherein the first optical element comprises a first holographic recording medium, wherein the first hologram is recorded in the first holographic recording medium, wherein the first hologram comprises a first thick phase hologram.

7. The apparatus of claim 1 wherein the first optical element comprises a first holographic recording medium, wherein the first hologram is recorded in the first holographic recording medium, wherein the first hologram comprises a first thin phase hologram.

8. The apparatus of claim 1 further comprising a fourth optical element, wherein the fourth optical element is positioned adjacent the first optical element and configured to receive the second light, wherein the fourth optical element is configured to converge the second light.

9. The apparatus of claim 1 further comprising a fourth optical element, wherein the fourth optical element is positioned adjacent the first optical element and configured to receive the second light, wherein the fourth optical element is configured to diverge the second light.

10. The apparatus of claim 1 wherein the display device is a color LCD display device, and wherein the first pixel emits multiple wavelengths of light.

11. The apparatus of claim 1 wherein the first, second, and third holograms are positioned within a single plane.

12. The apparatus of claim 1, wherein the first pixel comprises three sub-pixels, the first sub-pixel configured to emit red light, the second sub-pixel configured to emit green light and the third sub-pixel configured to emit blue light.

13. The apparatus of claim 1, wherein the first optical element is configured such that the passage of light emitted by a second pixel of the display device through the first optical element is substantially inhibited.

14. An apparatus comprising:

a display device comprising a plurality of light emitting pixels, wherein a first pixel is configured to emit a first and second light in first and second directions, respectively, wherein the first and second directions define a non-zero angle therebetween;

a first optical element comprising a first hologram, wherein the first optical element is positioned to receive the first light, wherein the first hologram is configured to diffract the first light, wherein the diffracted first light emerges from the first optical element in a direction substantially parallel to the second direction;

a second optical element positioned to receive the first diffracted light, and;

a third optical element positioned to receive the second light;

wherein the second optical element is configured to operate in an active state or an inactive state, wherein the second optical element is configured to transmit the diffracted first light without substantial alteration when the second optical element operates in the active state, and wherein the second optical element is configured to extinguish the diffracted first light when the second optical element operates in the active state;

wherein the third optical element is configured to operate in the active state or the inactive state, wherein the third optical element is configured to transmit the second light without substantial alteration when the third optical element operates in the active state, and wherein the third optical element is configured to extinguish the second light when the third optical element operates in the active state;

wherein the third optical element is configured to be active when the second optical element is inactive, and wherein the third optical element is configured to be inactive when the second optical element is active.

15. An apparatus comprising:

a display device comprising a plurality of light emitting pixels, wherein a first pixel is configured to emit a first and second light in first and second directions, respectively, wherein the first and second directions define a non-zero angle therebetween;

a first optical element comprising a first hologram, wherein the first optical element is positioned to receive the first light, wherein the first hologram is configured to diffract the first light, wherein the diffracted first light emerges from the first optical element in a direction substantially parallel to the second direction;

a second optical element comprising a second hologram, wherein the second optical element is positioned to receive the first diffracted light, and;

a third optical comprising a third hologram, wherein the third optical element is positioned to receive the second light;

wherein the second optical element is configured to operate in an active state or an inactive state, wherein the second optical element is configured to transmit the diffracted first light without substantial alteration when the second optical element operates in the active state, and wherein the second optical element is configured to diffract the diffracted first light when the second optical element operates in the active state, wherein the twice diffracted first light emerges from the second optical element at a third direction, wherein the second and third directions define a non-zero angle therebetween;

wherein the third optical element is configured to operate in the active state or the inactive state, wherein the third optical element is configured to transmit the second light without substantial alteration when the third optical element operates in the active state, and wherein the third optical element is configured to diffract the second light when the third optical element operates in the active state, wherein the diffracted second light emerges from the third optical element in a fourth direction, wherein the fourth and second directions define a non-zero angle therebetween;

wherein the third optical element is configured to be active when the second optical element is inactive, and wherein the third optical element is configured to be inactive when the second optical element is active.

16. The apparatus of claim 15:

wherein the second hologram is one of three holograms comprised in the second optical element, wherein each of the three holograms of the second optical element is configured to operate in the active state or the inactive state, wherein each of the three holograms of the second optical element is configured to diffract a distinct visible bandwidth of light when operating in the active state, and wherein each of the three holograms of the second optical element is configured to transmit substantially all visible bandwidth without diffraction when operating in the inactive state;

wherein the third hologram is one of three holograms comprised in the third optical element, wherein each of the three holograms of the third optical element is configured to operate in the active state or the inactive state, wherein each of the three holograms of the third optical element is configured to diffract a distinct visible-bandwidth of light when operating in the active state, and wherein each of the three holograms of the third optical element is configured to transmit substantially all visible bandwidth without diffraction when operating in the inactive state.

17. The apparatus of claim 15 wherein the three holograms of the second and third optical elements are positioned within a common plane.

18. The apparatus of claim 15 wherein the three holograms of the second optical element are aligned on a first common axis, and wherein the three holograms of the third optical element are aligned on a second common axis, wherein the first and second common axes are spaced apart and parallel.

19. An apparatus comprising:

a display device comprising a plurality of light emitting pixels, wherein a first pixel is configured to emit a first and second light in first and second directions, respectively, wherein the first and second directions define a non-zero angle therebetween;

a first optical element comprising a first hologram, wherein the first optical element is positioned to receive the first light, wherein the first hologram is configured to diffract the first light, wherein the diffracted first light emerges from the first optical element in a direction substantially parallel to the second direction;

wherein the first optical element comprises a front and a back surface, wherein the first optical element is configured to diffract the first light if the first light is received on the front surface at an angle that is within a predefined range of angles measured with respect to a normal to the front surface, and wherein the first optical element is substantially opaque to the first light if the first light is received on the front surface at an angle that is outside the predefined range of angles angle measured with respect to a normal to the front surface.

20. A display system comprising:

a display device comprising a first pixel and a second pixel, the first and second pixels being separated from each other by a non-light producing space, wherein the first and second pixels are configured to emit light in a forward direction;

a holographic optical element having a front and back surface, the holographic optical element being positioned in front of the first and second pixels over at least a portion of the non-light producing space, wherein light emitted from the first pixel strikes the back surface of the holographic optical element, and wherein the holographic element diffracts the light emitted from the first pixel such that the diffracted light emerges from the front surface of the holographic optical element substantially normal to the front surface of the holographic optical element, and wherein at least a portion of the diffracted light emerges from the holographic optical element at a position in front of the intervening non-light producing space, and wherein the holographic optical element is configured such that the passage of light emitted by the second pixel through the holographic optical element is substantially inhibited;

a first shutter element positioned in front of the holographic optical element, and wherein the first shutter element is substantially opaque to light when in an active state, and wherein the second shutter element is substantially transparent to light in an inactive state; and

a second shutter element positioned in front of the pixel, wherein the second shutter element is substantially opaque to light when in an active state, and wherein the second shutter element is substantially transparent to light in an inactive state.

21. The display system of claim 20, wherein the holographic optical element is formed from a polymer dispersed liquid crystal material, and wherein the holographic optical element is switchable between an active state and an inactive state.

22. The display system of claim 20, wherein the entire holographic optical element is positioned in front of the non-light producing space.

23. The display system of claim 22, further comprising an additional holographic optical element, the additional holographic element being substantially optically aligned with the pixel and adjacent to the holographic optical element.

24. The display system of claim 23, wherein the additional holographic element is substantially contained within the outer boundary of the first pixel.

25. The display system of claim 20, wherein the first shutter element is configured to be in an active state when the second shutter element is in an inactive state, and wherein the second shutter element is configured to be in an active state when the first shutter element is in an inactive state.

26. The display system of claim 20, wherein the first and second shutter elements are switchable holographic optical elements.

27. The display system of claim 20, wherein the display device is a color LCD display device, and wherein the pixel emits multiple wavelengths of light.

28. The display system of claim 20, wherein the holographic optical element comprises three superimposed switchable holograms, wherein the first hologram is configured to diffract red light, wherein the second hologram is configured to diffract green light, and wherein the third hologram is configured to diffract blue light.

29. The display system of claim 20, wherein the pixel comprises three sub-pixels, the first sub-pixel emitting red light, the second sub-pixel emitting green light and the third sub-pixel emitting blue light, and wherein the holographic optical element comprises three sub-holograms, wherein the first sub-hologram is configured to diffract red light, wherein the second sub-hologram is configured to diffract green light, and wherein the third sub-hologram is configured to diffract blue light.

30. The display system of claim 20, wherein the holographic element is a switchable holographic optical element, and wherein the holographic optical element extends over the first and second pixels, and wherein the holographic optical element in an inactive state allows light traveling in a normal direction to the holographic optical element to pass through the element, and wherein the holographic optical element in an active state allows only light incident at a predefined angle to pass through the holographic optical element, and wherein the holographic optical element in an active state diffracts the incident light such that it emerges in a substantially normal direction from the holographic optical element.

31. An apparatus for enhancing the resolution of a display device, the display device comprising an array of pixels, the apparatus comprising

a holographic optical element layer comprising an array of holograms having a spatial frequency equal to the spatial frequency of the pixels of the display device;

a shutter element layer positioned in front of the holographic optical element layer, the shutter element layer comprising a first array of shutters and a second array of shutters, the first array of shutters and the second array of shutters having a spatial frequency equal to the spatial frequency of the array of holograms, wherein the first array of shutter and the second array of shutters are coplanar and non-overlapping, and wherein the first array of shutters are in front of the array of holograms;

wherein the apparatus is positionable over the display device such that the second array of shutters is in front of the pixels of the display.

32. The apparatus of claim 31, wherein the holographic optical element layer is formed from a liquid crystal material.

33. The apparatus of claim 31, wherein the array of holograms are switchable holograms.

34. The apparatus of claim 31, wherein the holographic optical element layer is formed from a polymer dispersed liquid crystal material.

35. The apparatus of claim 31, wherein the array of holograms comprises an array of diffraction grating holograms.

36. The apparatus of claim 31, further comprising an additional array of holograms formed in the holographic optical element layer, the additional array of holograms being coplanar and non-overlapping with the array of holograms, and wherein the additional array of holograms are in front of the pixels of the display device during use.

37. The apparatus of claim 31, wherein the additional array of holograms comprises an array of light converging holograms.

38. The apparatus of claim 31, wherein the additional array of holograms comprises an array of light diffusing holograms.

39. The apparatus of claim 31, wherein the light emitted from the array of holograms passes through the first array of shutters and emerges from the front surface of the first array of shutters when the first array of shutters is in an inactive state, and wherein the light emitted from the array of holograms is inhibited from passing through the first array of shutters when the first array of shutters is in an active state;

and wherein light emitted from the array of pixels passes through the second array of shutters and emerges from the front surface of the second array of shutters when the second array of shutters is in an inactive state, and wherein the light emitted from the array of pixels is inhibited from passing through the second array of shutters when the second array of shutters is an active state.

40. The apparatus of claim 39, wherein the first array of shutters is configured to be in an active state when the second array of shutters is in an inactive state, and wherein the second array of shutters is configured to be in an active state when the first array of shutters is in an inactive state.

41. The apparatus of claim 40, wherein the first and second array of shutters are composed of switchable holographic optical elements.

42. The apparatus of claim 31, wherein each hologram of the array of holograms comprises three superimposed switchable holograms, wherein a first switchable hologram is configured to diffract red light, and wherein a second switchable hologram is configured to diffract green light, and wherein a third switchable hologram is configured to diffract blue light.

43. The display system of claim 31, further comprising a light diffusing optical element positioned in front of the holographic optical element.

44. A display system comprising:

a display device comprising a pixel, wherein the pixel is configured to emit light in a forward direction from the pixel; and

a switchable holographic optical element having a front and back surface, the switchable holographic optical element being positioned in front of the pixel, wherein the switchable holographic optical element is substantially transparent to light incident at a predefined range of angles when in an active state, and wherein the switchable holographic optical element is substantially opaque to light incident at an angle which differs from the predefined range of angles when in an active state, and wherein the switchable holographic optical element is substantially transparent to light in an inactive state.

45. The display system of claim 44, wherein the switchable holographic optical element is formed from a polymer dispersed liquid crystal material.

46. The display system of claim 44, wherein the holographic optical element defines a hologram of a diffraction grating.

47. The display system of claim 44, wherein the display device is a color LCD display device, and wherein the pixel emits multiple wavelengths of light.

48. The display system of claim 44, wherein the holographic optical element comprises three superimposed switchable holograms, and wherein a first switchable hologram is configured to diffract red light, and wherein a second switchable hologram is configured to diffract green light, and wherein a third switchable hologram is configured to diffract blue light.

49. The display system of claim 44, wherein the pixel emits monochromatic light.

50. The display system of claim 44, wherein the pixel comprises three sub-pixels, the first sub-pixel emitting red light, the second sub-pixel emitting green light and the third sub-pixel emitting blue light, and wherein the holographic optical element comprises three sub-holograms, wherein the first sub-hologram is configured to diffract red light, wherein the second sub-hologram is configured to diffract green light, and wherein the third sub-hologram is configured to diffract blue light.

51. The display system of claim 44, further comprising a light diffusing optical element positioned in front of the holographic optical element.

52. A method of enhancing the resolution of a display device, comprising providing a display system, the display system comprising:

a display device comprising a pixel, wherein the pixel is configured to emit light in a forward direction from the pixel;

a holographic optical element having a front and back surface, the holographic optical element being positioned in front of the pixel such that at least a portion of the holographic optical element extends beyond an outer boundary of the pixel, wherein the holographic optical element is substantially transparent to light incident at a predefined range of angles, and wherein the holographic optical element is substantially opaque to light incident at an angle which differs from the predefined range of angles;

a first shutter element having a front and back surface, the first shutter element being positioned in front of the holographic optical element and in front of the holographic optical element, wherein the first shutter element is substantially opaque to light when in an active state, and wherein the first shutter element is substantially transparent to light in an inactive state;

a second shutter element having a front and back surface, the second shutter element being positioned in front of the pixel and in front of the pixel, wherein the second shutter is substantially opaque to light when in an active state, and wherein the second shutter is substantially transparent to light in an inactive state;

activating the pixel such that the pixel emits a first light pattern;

switching the first shutter to an active state such that the light emitted from the holographic optical element is substantially inhibited from passing through the first shutter;

substantially simultaneously switching the second shutter to an active state while switching the first shutter to an inactive state, wherein switching the second shutter to an active state substantially inhibits light emitted normal to the pixel from being transmitted through the shutter.

53. The method of claim 52, further comprising activating the pixel to emit a second light pattern while substantially simultaneously activating the second shutter and inactivating the first shutter.

54. The method of claim 53, wherein substantially simultaneously activating the second shutter and inactivating the first shutter is coordinated with activating the pixel to emit the second light pattern such that the first light pattern is emitted through the second shutter, and the second light pattern is emitted through the first shutter.

55. The method of claim 53, wherein the first and second shutter elements are switchable holographic optical elements.

56. The method of claim 53, wherein the display device is a color LCD display device, and wherein the pixel emits multiple wavelengths of light, and wherein the pixel sequentially emits red, green and blue light when activated.

57. The method of claim 56, wherein the holographic optical element comprises three superimposed switchable holograms, and wherein a first switchable hologram is configured to diffract red light when activated, and wherein a second switchable hologram is configured to diffract green light when activated, and wherein a third switchable hologram is configured to diffract blue light when activated, and wherein the first, second and third switchable holograms are configured to be substantially transparent to light in an inactive state, and further comprising sequentially activating one of the switchable holograms while the other two holograms remain in an inactive state, wherein the sequential activation of the switchable holograms is synchronized with the sequence of light emitted by the pixel.

58. The method of claim 57, wherein substantially simultaneously activating the second shutter and inactivating the first shutter is synchronized with the display refresh rate.

59. A method of enhancing the resolution of a display device, comprising:

placing an apparatus for enhancing the-resolution of a display device, the display device comprising an array of pixels, the apparatus comprising;

a holographic optical element layer comprising an array of holograms having a spatial frequency equal to the spatial frequency of the pixels of the display device;

a shutter element layer positioned in front of the holographic optical element layer, the shutter element layer comprising a first array of shutters and a second array of shutters, the first array of shutters and the second array of shutters having a spatial frequency equal to the spatial frequency of the array of holograms, wherein the first array of shutter and the second array of shutters are coplanar and non-overlapping, and wherein the first array of shutters are in front of the array of holograms;

aligning the apparatus over the display device such that the array of holograms is substantially offset from the array of pixels, and wherein the second array of shutters is in front of the pixels of the display;

activating the array of pixels such that the pixels emits a first light pattern;

switching the first array of shutters to an active state such that the light emitted from the holographic optical element is substantially inhibited from passing through the first array of shutters, and wherein the first fight pattern appears to emanate from the array of pixels;

activating the array of pixels such that the pixels emit a second light pattern; and

substantially simultaneously switching the second array of shutters to an active state while switching the first array of shutters to an inactive state, wherein switching the second array of shutters to an active state substantially inhibits light emitted normal to the pixel from being transmitted through the second array of shutters, and wherein the second light pattern appears to emanate from the array of holograms.

60. The method of claim 59, wherein the display device is a color LCD display device, and wherein the pixel emits multiple wavelengths of light, and wherein the pixel sequentially emits red, green and blue light when activated.

61. The method of claim 60, wherein the holographic optical element comprises three superimposed switchable holograms, and wherein a first switchable hologram is configured to diffract red light when activated, and wherein a second switchable hologram is configured to diffract green light when activated, and wherein a third switchable hologram is configured to diffract blue light when activated, and wherein the first, second and third switchable holograms are configured to be substantially transparent to light in an inactive state, and further comprising sequentially activating one of the switchable holograms while the other two holograms remain in an inactive state, wherein the sequential activation of the switchable holograms is synchronized with the sequence of light emitted by the pixel.

62. The method of claim 59, wherein the display device is an interlaced display device, and wherein the first light pattern corresponds to the even fields of an interlaced display and wherein the second light pattern corresponds to the odd fields of an interlaced display.

63. The method of claim 59, wherein the display device is a progressive display, and wherein the first pattern of light corresponds to half of an image information, and wherein the second pattern corresponds to the complementary half of the image information.

64. A method of enhancing the resolution of a display device, comprising:

providing a display system, the display system comprising;

a display device comprising a pixel, wherein the pixel is configured to emit light emanating in a forward direction from the pixel; and

a switchable holographic optical element having a front and back surface, the switchable holographic optical element being positioned in front of the pixel, wherein the switchable holographic optical element is substantially transparent to light incident at a predefined range of angles when in an active state, and wherein the switchable holographic optical element is substantially opaque to light incident at an angle which differs from the predefined range of angles when in an active state, and wherein the switchable holographic optical element is substantially transparent to light in an inactive state;

activating the pixel such that the pixel emits a first light pattern while the switchable holographic optical element is in an inactive state;

switching the switchable holographic optical element to an active state.