Display device

• US 20050017648A1
• Filed: 07/22/2004
• Published: 01/27/2005
• Est. Priority Date: 07/22/2003
• Status: Abandoned Application

• Current Assignee: Yeda Research and Development Co. Ltd. (Weizmann Institute of Science)
• Original Assignee: Yeda Research and Development Co. Ltd. (Weizmann Institute of Science)
• Inventors: Halahmi, Erez, Naaman, Ron
• Application Number:
  US10/895,994
• Publication Number:
  US 20050017648A1
• Time in Patent Office: Days
• US Class Current: 315/169.100
• CPC Class Codes: H01J 21/10 with one or more immovable internal control electrodes, e.g. triode, pentode, octode
• CPC Class Codes: H01J 3/021 Electron guns using a field emission, photo emission, or secondary emission electron source

Abstract

A display device is presented. The display device includes an electrodes'"'"' arrangement and an electrons'"'"' extractor. The electrodes'"'"' arrangement comprises a Cathode electrode layer having at least one Cathode electrode and an Anode electrode layer having at least one Anode electrode, the Cathode and Anode electrode layers being accommodated in a spaced-apart relationship with a gap between them. The Anode layer carries a luminescent screen assembly on its surface. The electrodes arrangement is operable to create a desired electrical field between the electrodes. The electrons'"'"' extractor operates to extract electrons from at least a selected region of the Cathode electrode layer by illuminating this Cathode region with exciting illumination of a predetermined wavelength range to cause the electron emission from the illuminated Cathode region.

Claims

1. A display device comprising:

an electrodes'"'"' arrangement including a Cathode electrode layer having at least one Cathode electrode and an Anode electrode layer having at least one Anode electrode, the Cathode and Anode electrode layers being accommodated in a spaced-apart relationship with a gap between them, the Anode electrode layer carrying a luminescent screen assembly on its surface, the electrodes arrangement being operable to create a desired electrical field between the electrodes;

an electrons'"'"' extractor for extracting electrons from at least a selected region of the Cathode electrode layer by illuminating said at least selected region of the Cathode electrode layer with exciting illumination of a predetermined wavelength range to cause the electron emission from the illuminated Cathode region.

2. The device of claim 1, wherein a material of the Cathode electrode layer and the predetermined wavelength range are such that work function of the Cathode layer material is higher than energy of photons outside said predetermined wavelength range.

3. The device of claim 1, wherein said predetermined wavelength range includes the red part of optical spectrum.

4. The device of claim 1, wherein said electrons'"'"' extractor comprises at least one light unit configured and oriented with respect to the electrodes'"'"' arrangement so as to illuminate at least the Cathode electrode.

5. The device of claim 1, wherein said electrons'"'"' extractor comprises at least one light unit configured and oriented with respect to the electrodes'"'"' arrangement so as to illuminate the entire surface of the Cathode electrode layer by which it faces the Anode electrode layer.

6. The device of claim 1, wherein said electrons'"'"' extractor comprises at least one light unit configured and oriented with respect to the electrodes'"'"' arrangement so as to illuminate the entire inner surfaces of the Cathode and Anode electrode layers by which they face each other.

7. The device of claim 1, wherein said electrons'"'"' extractor comprises at least one light unit accommodated outside the electrodes'"'"' arrangement and oriented so as to illuminate the inner surface of the Cathode electrode layer, by which it faces the Anode electrode layer, through the Cathode layer, the Cathode layer being at least partially transparent with respect to said predetermined wavelength range.

8. The device of claim 7, wherein the Cathode layer is located on a substrate made of a material at least partially transparent with respect to said predetermined wavelength range.

9. The device of claim 5, wherein said at least one light unit is configured as a frame-like structure surrounding a space between the Cathode and Anode layers.

10. The device of claim 6, wherein said at least one light unit is configured as a frame-like structure surrounding a space between the Cathode and Anode layers.

11. The device of claim 5, wherein said electrons'"'"' extractor comprises an array of light units arranged in a spaced-apart relationship to form a frame-like structure surrounding a space between the Cathode and Anode layers.

12. The device of claim 6, wherein said electrons'"'"' extractor comprises an array of light units arranged in a spaced-apart relationship to form a frame-like structure surrounding a space between the Cathode and Anode layers.

13. The device of claim 1, wherein the gap between the Cathode and Anode layers is evacuated.

14. The device of claim 1, wherein the Cathode and Anode layers are spaced from each other by the gas-medium gap.

15. The device of claim 1, wherein the Cathode and Anode layers are spaced from each other by the air gap.

16. The device of claim 14, wherein a gas pressure in the gap between the Cathode and Anode layers is selected so as to provide a mean free path of electrons accelerating from the Cathode to the Anode larger than a length of the gap between the Cathode and the Anode layers.

17. The device of claim 1, wherein at least one of the Cathode and Anode electrode layers is formed by an array of spaced-apart electrode-elements, defining an image pixel array of the display device.

18. The device of claim 1, wherein the Cathode electrode layer is formed by an array of spaced-apart Cathode-elements defining an image pixel array of the display device.

19. The device of claim 1, wherein the Cathode electrode layer is patterned to define a first array of elongated spaced-apart parallel Cathode-elements extending along a first axis, and the Anode electrode layer is patterned to define a second array of spaced-apart parallel Anode-elements extending along a second axis perpendicular to the first axis, the first and second arrays defining together a two-dimensional image pixel array of the display device.

20. The device of claim 17, comprising a control unit operating the electrodes'"'"' arrangement to selectively effect a change in a potential difference between the selective one of the electrode-elements of said at least one of the Cathode and Anode layers and the other of said electrode layers.

21. The device of claim 17, comprising a control unit operating the electrodes'"'"' arrangement to selectively effect a change in a potential difference between the selected one of the Cathode electrode-elements and a corresponding one of the Anode electrode-elements aligned with said selected Cathode electrode-element.

22. The device of claim 20 or 21, wherein the control unit operates the electrons'"'"' extractor to provide a certain intensity of said illumination of the surface of the Cathode electrode layer by which it faces the Anode layer.

23. The device of claim 20 or 21, wherein the control unit operates the electrons'"'"' extractor to provide the controllable variable illumination of the surface of the Cathode electrode layer by which it faces the Anode layer.

24. The device of claim 1, wherein the electrodes'"'"' arrangement comprises a Gate electrode layer accommodated between the Cathode and Anode electrode layers.

25. The device of claim 24, wherein at least one of the Cathode and Anode electrode layers is formed by an array of spaced-apart electrode-elements, defining an image pixel array of the display device.

26. The device of claim 25, wherein the Gate electrode layer is in the form of a grid allowing a material propagation therethrough.

27. The device of claim 26, comprising a control unit operating the electrodes'"'"' arrangement to maintain a certain potential difference between the Cathode electrode layer and the Anode electrode layer, and to selectively apply a certain potential difference between the Gate electrode layer and at least one selected electrode-element thereby effecting a change in an electric current between said at least one electrode-element and the other one of the Cathode and Anode layers, as compared to that of the other electrode-elements, thus effecting actuation of at least one selected image pixel of the display device.

28. The device of claim 27, wherein the control unit operates the electrons'"'"' extractor to provide a certain value of said illumination of the surface of the Cathode electrode layer by which it faces the Anode layer.

29. The device of claim 27, wherein the control unit operates the electrons'"'"' extractor to provide the controllably variable illumination of the surface of the Cathode electrode layer by which it faces the Anode layer.

30. The device of claim 25, wherein the Gate electrode layer is in the form of an array of Gate electrode-elements arranged in a spaced-apart relationship in accordance with a pixel array of the device.

31. The device of claim 30, comprising a control unit operating the electrodes'"'"' arrangement to maintain a certain potential difference between the Cathode and Anode electrode layers, and to selectively apply a certain potential difference between a selected one of the Gate electrode-elements and a corresponding one of the Cathode electrode-elements thereby effecting a change in an electric current between the selected electrode-elements, as compared to that of the other electrode-elements and thus effecting actuation of at least one selected image pixel of the display device.

32. The device of claim 31, wherein the control unit operates the electrons'"'"' extractor to provide a certain value of said illumination of the surface of the Cathode electrode layer by which it faces the Anode layer.

33. The device of claim 31, wherein the control unit operates the electrons'"'"' extractor to provide the controllably variable illumination of the surface of the Cathode electrode layer by which it faces the Anode layer.

34. The device of claim 1, comprising a control unit operating the electrons'"'"' extractor to illuminate the at least one selected region of the Cathode electrode layer thereby affecting an electric current between the Anode electrode layer and said at least one selected region of the Cathode layer, thus effecting actuation of at least one selected image pixel of the display device.

35. The device of claim 34, wherein the control unit operates the electrodes'"'"' arrangement to maintain a certain potential difference between the Cathode and Anode electrode layers.

36. The device of claim 34, wherein the control unit operates the electrodes'"'"' arrangement to controllably vary a potential difference between the Cathode and Anode electrode layers.

37. The device of claim 1, wherein said electrons'"'"' extractor is in the form of an array of light units defining an image pixel array, said array of light units being arranged in a spaced-apart relationship such that each of the light units is associated with a corresponding region of the Cathode electrode layer.

38. The device of claim 37, wherein each of said light units is addressed by power supply, operation of at least one selected light units to illuminate the at least one corresponding region of the Cathode electrode layer resulting is actuation of the at least one selected image pixel.

39. The device of claim 37, wherein each of said light units is operable to be shiftable between its different operational modes to thereby vary intensity of light produced by the light unit, thereby allowing actuation of the at least one selected image pixel.

40. The device of claim 37, wherein the electrons'"'"' extractor is configured to prevent a change of the illumination intensity actuating the selected pixel from affecting a change in an electric current of a locally adjacent pixel.

41. The device of claim 40, wherein the electrons extractor comprises an optical mask located adjacent to the array of light units.

42. The device of claim 41, wherein the optical mask is in the form of an array of spaced-apart light blocking regions, said light units being located within the spaces, respectively, between the light blocking regions

43. The device of claim 41, wherein the optical mask is an optically insulating structure patterned to define an array of projections spaced-apart by grooves, said light units being located in said grooves so as to be spaced-apart from each other by said projections.

44. The device of claim 37, wherein the Cathode electrode layer is formed by an array of tip-like Cathode-elements projecting towards the Anode electrode layer, each of said light units being located proximate to the corresponding one of said tip-like Cathode-element, operating one of the light units resulting in maximally affecting an electric current between the corresponding tip-like Cathode-element and the Anode electrode, as compared to that of Cathode layer regions adjacent to said tip-like element.

45. The device of claim 37, wherein the array of light units is accommodated outside the electrode'"'"'s arrangement at the side of the Cathode electrode layer, the Cathode layer being made of a material at least partially transparent with respect to said predetermined wavelength range.

46. The device of claim 45, wherein the Cathode layer is carried on a substrate made of a material at least partially transparent with respect to said predetermined wavelength range.

47. The device of claim 1, wherein a structure formed by the Anode electrode layer with the luminescent screen assembly thereon is at least partially transparent.

48. The device of claim 47, wherein the luminescent screen structure is carried by the inner surface of the Anode electrode layer by which it faces the Cathode electrode layer.

49. The device of claim 47, wherein said electrons'"'"' extractor utilizes external radiation for illuminating the Cathode electrode layer through the Anode electrode layer.

50. The device of claim 1, configured and operable to enable identification of an externally pointed location on the outer surface of a structure formed by the Anode layer with the luminescent screen thereon.

51. The device of claim 50, wherein said structure formed by the Anode layer with the luminescent screen thereon is configured to be sufficiently flexible such that pointing the selected location by touching the outer surface of said structure within the selected location causes a local deformation of the structure at the touched location, thereby causing a change in an electric current between the Cathode and Anode layer regions aligned with the touched location, as compared to all the other regions, and enabling identification of the touched location by detecting this change.

52. The device of claim 50, wherein

said electrons'"'"' extractor comprises at least one light unit accommodated to illuminate the inner surface of the Cathode electrode layer by which it faces the Anode layer by light reflections from the Anode layer,

said structure formed by the Anode layer with the luminescent screen thereon is configured to be sufficiently flexible such that pointing the selected location by touching the outer surface of said structure within the selected location causes a local deformation of the structure at the touched location, said local deformation causing a local change in a light scattering effect, thereby causing a local change in the electric current between the Cathode and Anode layers regions aligned with the touched location.

53. The device of claim 50, wherein said structure formed by the Anode layer with the luminescent screen assembly thereon is configured to be sufficiently flexible such that pointing the selected location by touching the outer surface of said structure within the selected location causes a local deformation of the structure at the touched location, said local deformation causing a local change in a distance between the Anode and the Cathode layers thus causing a local change in an electric field resulting in a local change in the electric current between the Cathode and Anode layers regions aligned with the touched location.

54. The device of claim 47, configured and operable to enable identification of an externally pointed location of the display device, touching an external surface of the Anode electrode layer within said location causing a local change in the illuminating light intensity at a region of the Cathode electrode layer aligned with the touched location due to a local change in external light propagating to the Cathode through the Anode at the touched location, thereby enabling identification of the touched location as a change in an electric current between the Cathode and Anode layer regions underneath the touched location.

55. The device of claim 47, operable to enable identification of a remotely pointed location on an outer surface of a structure formed by the Anode electrode layer with the luminescent screen thereon, light coming from outside of the device through the remotely pointed location towards a corresponding region of the Cathode layer causing a local change in an electric current between the Anode layer and the selected region of the Cathode layer.

56. A display device comprising:

an electrodes'"'"' arrangement including a Cathode electrode layer having at least one Cathode electrode and an Anode electrode layer having at least one Anode electrode, the Cathode and Anode electrode layers being accommodated in a spaced-apart relationship with a gap between them, and a Gate electrode layer in the form of a grid located between the Cathode and Anode layers, the Anode layer carrying a luminescent screen structure on its surface, at least one of the Cathode and Anode electrode layers being formed by an array of spaced-apart electrode-elements defining an image pixel array of the display device,

an electrons'"'"' extractor configured and operable to produce exciting radiation to illuminate at least a selected region of the Cathode electrode layer to extract electrons from the illuminated Cathode electrode;

a control unit for operating the electrodes'"'"' arrangement by supplying voltages to the electrodes, and operating the electrons'"'"' extractor to illuminate the Cathode electrode;

the device being operable to actuate a selective image pixel by carrying out at least one of the following;

varying the voltage supply to the Gate, and modifying the illumination reaching the Cathode layer.

57. A display device comprising:

an electrodes'"'"' arrangement including a Cathode electrode layer having at least one Cathode electrode and an Anode electrode layer having at least one Anode electrode, the Cathode and Anode layers being accommodated in a spaced-apart relationship with a gap between them, the Anode layer carrying a luminescent screen assembly on its surface, a structure formed by the Anode layer with the luminescent screen assembly thereon being at least partially optically transparent; and

an electrons'"'"' extractor configured and operable to produce exciting radiation to extract electrons from the Cathode electrode by illuminating at least a selective region of the Cathode electrode layer by the exciting radiation propagating to the Cathode through the Anode electrode layer.

58. A display device comprising:

an electrodes'"'"' arrangement including a Cathode electrode layer having at least one Cathode electrode and an Anode electrode layer having at least one Anode electrode, the Cathode and Anode layers being spaced by a gap, the Anode layer carrying a luminescent screen assembly on its surface;

an electrons'"'"' extractor operable to produce exciting radiation to extract electrons from the Cathode, the electrons'"'"' extractor comprising an array of light units arranged in accordance with an image pixel array, the light units being accommodated such that each of the light units illuminates a corresponding region of the Cathode electrode layer and thus extracts electrons therefrom.

59. A display device comprising:

an electrodes'"'"' arrangement including a Cathode electrode layer having at least one Cathode electrode and an Anode electrode layer having at least one Anode electrode, the Cathode and Anode layers being accommodated in a spaced-apart relationship with a gap between them, the Anode layer carrying a luminescent screen assembly on its surface, the Cathode electrode layer being made of a material at least partially transparent with respect to a spectral range of exciting radiation;

an electrons'"'"' extractor configured to produce the exciting radiation to extract electrons from the Cathode, the electrons'"'"' extractor comprising an array of light units arranged in a spaced-apart relationship in accordance with an image pixel array, the light units being accommodated outside the electrodes'"'"' arrangement, each of the light units being separately operated to illuminate a corresponding region of the inner surface of the Cathode electrode layer through the Cathode layer to thereby extract electrons from the illuminated Cathode region towards the Anode layer.

60. A display device configured to define an array of image pixels, the device comprising an electrodes'"'"' arrangement, and an illuminator assembly configured and operable to produce exciting illumination to extract electrons from a Cathode electrode.

61. A display device comprising an electron emission device comprising an electrodes'"'"' arrangement including at least one Cathode electrode and at least one Anode electrode, the Cathode and Anode electrodes being arranged in a spaced-apart relationship;

the electron emission device being configured to expose said at least one Cathode electrode to exciting illumination to thereby cause electrons'"'"' emission from said Cathode electrode.

62. A display device comprising an electron emission device comprising an electrodes'"'"' arrangement including at least one Cathode electrode, at least one Anode electrode, and at least one Gate electrode, the electrodes being arranged in a spaced-apart relationship;

the electron emission device being configured to expose said at least one Cathode electrode to exciting illumination to thereby cause electrons'"'"' emission from said Cathode electrode.

63. A display device configured to define an array of image pixels, the device comprising an electrodes'"'"' arrangement, and an illuminator assembly producing exciting radiation to extract electrons from a Cathode electrode, the illuminator assembly being configured and operable to illuminate a surface of the Cathode electrode, by which it faces an Anode electrode, through the Cathode electrode made of a material at least partially transparent with respect to the exciting illumination.

64. A method for operating a display device which includes a Cathode electrode layer and an Anode electrode layer, the method comprising illuminating at least a selected region of the Cathode electrode layer with exciting radiation to extract electrons from the at least one illuminated Cathode region, thereby affecting an electric current between said at least one selected region of the Cathode electrode and an Anode electrode layer.

65. The method of claim 64, comprising selectively effecting a change in an electric field between two selected regions of the Cathode electrode layer and the Anode electrode layer, respectively, as compared to other regions of the Cathode and Anode layers, to thereby actuate a selective pixel of the display device.

66. The device of claim 65, comprising maintaining a certain value of the exciting illumination.

67. The device of claim 65, comprising controllably modifying the illumination.

68. The device of claim 65, wherein said change in the electric field is affected as a changed in a potential difference between said two selected regions of the Cathode electrode layer and the Anode electrode layer.

69. The device of claim 65, wherein said change in the electric field is affected as a changed in a voltage supply to a Gate electrode.

70. The method of claim 64, comprising selectively illuminating at least one region of the Cathode layer to extract electrons therefrom, thereby effecting a change in an electric current between said at least one Cathode region and the Anode layer, as compared to the other Cathode regions, thereby actuating at least one selected pixel of the display device.

71. The method of claim 70, comprising controllably varying an electric field between said at least one Cathode region and the Anode layer.

72. The method of claim 70, comprising maintaining a certain value of an electric field between said at least one Cathode region and the Anode layer.

73. The method of claim 71, wherein the controllable variation of the electric field comprises controllably varying a potential difference between said at least one Cathode region and the Anode layer.

74. The method of claim 71, the controllable variation of the electric field comprises controllably varying a voltage supply to a Gate electrode.

75. A display device comprising an electrodes'"'"' arrangement including a Cathode electrode layer and an Anode electrode layer which are accommodated in spaced-apart parallel planes with a gas-medium gap between them of a length substantially not exceeding a mean free path of electrons in said gas medium, the Anode layer carrying a luminescent screen assembly on its surface.

76. The device of claim 75, wherein the length of the gap between the Cathode and Anode electrodes substantially does not exceed 800 nm.

77. The device of claim 75, wherein the length of the gap between the Cathode and Anode electrodes is of about a few tens of nanometers.

78. The device of claim 75, wherein the length of the gap between the Cathode and Anode electrodes is from a few tens of nanometers up to a few hundreds of nanometers.