Tiled flat panel displays

• US 5,889,568 A
• Filed: 12/12/1995
• Issued: 03/30/1999
• Est. Priority Date: 12/12/1995
• Status: Expired due to Term

• Current Assignee: Hanger Solutions, LLC (IP Investments Group LLC)
• Original Assignee: Rainbow Displays, Inc.
• Inventors: Seraphim, Donald P., Li, Che-yu, Krusius, J. Peter
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Ngo, Julie
• Application Number:
  US08/571,208
• Time in Patent Office: 1,204 Days
• Field of Search: 345/1, 345/76, 345/903, 349/73, 349/149
• US Class Current: 349/73
• CPC Class Codes: G02F 1/1333 Constructional arrangements; Manufacturing methodsG02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/13336 Combining plural substrates to produce large-area displays, e.g. tiled displays

Abstract

A large flat panel display having a plurality of tile display modules with capability in the range of 12 or more lines per inch, being precisely manufactured and aligned such that the interpixel spacing between two adjacent tiles maintains the uniformly periodic spacing of the interpixel spacing within tiles. The display is addressed as a single monolithic display, without reference to the plurality of individual tiles making up the display. All of the interconnections between tiles are located between tiles in the "shadow area", unless all tiles can have an edge around the periphery of the display. Also disclosed are methods of making and assembling the tiles and the displays.

Claims

1. A large flat panel display comprising:

a) a plurality of tile display modules, each tile display module having a plurality of pixels arranged in a matrix having uniformly periodic interpixel spacing, said pixels comprising an active area and an inactive, dark area, and each tile display module having electrical interconnection means for addressing the pixels such that each pixel may be selectively controlled through the electrical interconnection means, and pads for interconnecting with the electrical interconnection means; and

b) a back plate for supporting and interconnecting the tile display modules, having at least one layer of optically opaque interconnection lines for connection to the electrical interconnection means of a plurality of the tile display modules, said at least one layer of optically opaque interconnection lines forming a light shield being disposed in said inactive, dark areas of said pixels, thereby forming a mask structure, the optically opaque interconnection lines having pads for electrical connection thereto;

the tile display modules being mounted upon the back plate, with the pads of the tile display modules being electrically connected to the pads of the interconnection lines of the back plate, aligning the tile display modules thereon, and located such that the interpixel spacing between two adjacent pixels on two adjacent tile display modules maintains the uniform periodicity of the interpixel spacing between adjacent pixels within the tile display modules, and

the pixels of the large flat panel display being addressed via the interconnection means of the back plate as if the large flat panel display comprising a plurality of tile display modules were a single monolithic large display.

2. The large flat panel display of claim 1 in which the tile display modules are backlit through the back plate.

3. The large flat panel display of claim 1 in which the tile display modules comprise liquid crystal displays.

4. The large flat panel display of claim 3 in which the liquid crystal displays are active matrix liquid crystal displays.

5. The large flat panel display of claim 1 in which the tile display modules comprise layers bonded together by an adhesive.

6. The large flat panel display of claim 5 in which the adhesive has conductive elements for connection to the electrical interconnection means of the tile display module.

7. The large flat panel display of claim 6 in which the conductive elements are conductive particles.

8. The large flat panel display of claim 5, in which each of the tile display modules further comprises lead frame type connections located in the dark space between tile display modules, and arranged such that the interpixel spacing between two adjacent pixels on two adjacent tile display modules maintains the uniform periodicity of the interpixel spacing between adjacent pixels within the tile display modules, the lead frame connections having a first end connected to the electrical interconnection means of the tile display module and a second end connected to the pads of the tile display module, and the first end of the lead frame type connections has a plurality of nodules for enhancing contact between the lead frame and the electrical interconnection means.

9. The large flat panel display of claim 8 in which the nodules are formed of a material selected from the group consisting of palladium, nickel and gold.

10. The large flat panel display of claim 5, in which each of the tile display modules further comprises lead frame type connections located in the dark space between tile display modules, and arranged such that the interpixel spacing between two adjacent pixels on two adjacent tile display modules maintains the uniform periodicity of the interpixel spacing between adjacent pixels within the tile display modules, the lead frame connections having a first end connected to the electrical interconnection means of the tile display module and a second end connected to the pads of the tile display module, and the first end of the lead frame type connections has a plurality of dendrites for enhancing contact between the lead frame and the electrical interconnection means.

11. The large flat panel display of claim 5 in which the adhesive also functions as a seal between the layers of the tile display modules.

12. The large flat panel display of claim 11 in which the adhesive is deposited around the edges of the tile display modules in a width such that the interpixel spacing between two adjacent pixels on two adjacent tile display modules maintains the uniform periodicity of the interpixel spacing between adjacent pixels within the tile display modules.

13. The large flat panel display of claim 5 in which the adhesive is conductive,

at least one of the facing sides of the layers is coated with a transparent conductive substance,

the facing side of the other layer has conductive pads in the seal area, and

the conductive pads of one of the layers are connected to the transparent conductive substance coated on the other layer.

14. The large flat panel display of claim 13 in which the transparent conductive substance comprises Indium Tin Oxide.

15. The large flat panel display of claim 11 in which:

the layers of the tile display modules comprise at least an upper and a lower plate of a liquid crystal display, with the liquid crystal being located between the upper and lower layers, contained by the adhesive acting as a seal, the seal being of a width such that the interpixel spacing between two adjacent pixels on two adjacent tile display modules maintains the uniform periodicity of the interpixel spacing between adjacent pixels within the tile display modules; and

a gap is left in the seal forming an orifice, and

the tile display modules further comprise a notch in one edge thereof, aligned with the orifice, and

the liquid crystal is introduced between the upper and lower layers by evacuating the area between the upper and lower areas, introducing the liquid crystal through the orifice, then sealing the orifice, such that the seal in the orifice fits in the notch in

the edge of the tile display modules and does not extend beyond the edge.

16. The large flat panel display of claim 15 in which the orifice is aligned with the dark space between the pixels.

17. The large flat panel display of claim 5 in which the first layer of each of the tile display modules is coated on the side facing the second layer with a transparent conductive substance, and the tile display module further comprises:

a) at least one ground intraconnection pad formed on the surface of the second layer of the tile display module in a shadow area between pixels, connected to at least one electrical interconnection means on the second layer;

b) conductive means for connecting the conductive substance on the surface of the first layer and the ground intraconnection pad when the first and second layers are in alignment.

18. The large flat panel display of claim 17 in which the conductive means is a conductive adhesive.

19. The large flat panel display of claim 17 in which the transparent conductive substance is Indium Tin Oxide.

20. The large flat panel display of claim 5 which each of the tile display modules further comprises a ledge formed on the edge of at least one layer of the tile display module, between the layers thereof.

21. The large flat panel display of claim 20 in which the ledge is formed by extending one edge of one of the layers beyond the edge of the facing layer.

22. The large flat panel display of claim 20 in which the ledge is inset into one of the two layers, the edges of the two layers being coterminous.

23. The large flat panel display of claim 20 in which the tile display module further comprises connector means located within the ledge for electrical connection to the electrical interconnection means of the tile display module.

24. The large flat panel display of claim 23 in which each of the tile display modules further comprises lead frame type connections, having a first end connected to the connector means located in the ledge, and a second end connected to the pads of the tile display module.

25. The large flat panel display of claim 24 in which the lead frame type connections are tape automated bonding connections.

26. The large flat panel display of claim 24 in which the lead frame type connections are metal applied on the edge of the tile display module.

27. The large flat panel display of claim 24 in which the lead frame type connections are wire bonds.

28. The large flat panel display of claim 24 in which the lead frame type connections are metal foil.

29. The large flat panel display of claim 24, in which the tile display module further comprises lead frame type connections located in the dark space between tile display modules, and arranged such that the interpixel spacing between two

pixels on two adjacent tile display modules maintains the uniform periodicity of the interpixel spacing between adjacent pixels within the tile display modules, the lead frame connections having a first end connected to the electrical interconnection means of the tile display module and a second end connected to the pad of the tile display module, and the first end of the lead frame type connections has a plurality of nodules for enhancing contact between the lead frame and the electrical interconnection means.

30. The large flat panel display of claim 29 in which the nodules are nickel and gold.

31. The large flat panel display of claim 24, in which the tile display module further comprises lead frame type connections located in the dark space between tile display modules, and arranged such that the interpixel spacing between two adjacent pixels on two adjacent tile display modules maintains the uniform periodicity of the interpixel spacing between adjacent pixels within the tile display modules, the lead frame connections having a first end connected to the electrical interconnection means of the tile display module and a second end connected to the pads of the tile display module, and the first end of the lead frame type connections has a plurality of dendrites for enhancing contact between the lead frame and the electrical interconnection means.

32. The large flat panel display of claim 1 in which the pixels of the tile display modules are addressed using a matrix of row and column interconnection lines, with each pixel being located at the intersection of at least one row and one column interconnection line, such that an individual pixel is addressed through activation of the row interconnection line and the column interconnection line intersecting at said pixel.

33. The large flat panel display of claim 1 in which the tile display modules comprise a display tile comprising a plurality of pixel means, mounted on a tile carrier.

34. The large flat panel display of claim 33 in which the electrical interconnection means of the tile display module is located on the tile carrier.

35. The large flat panel display of claim 34 in which the display tiles further comprise shadow areas between the pixels, and the electrical interconnection means is located in the shadow areas such that the electrical interconnection means does not block light transmitted by the pixels.

36. The large flat panel display of claim 33 in which the electrical interconnection means of the tile display module is located on the display tile.

37. The large flat panel display of claim 36 in which the electrical interconnection means of the tile display module comprise high-conductivity metal traces deposited on at least one surface of the tile display module.

38. The large flat panel display of claim 36 in which the display tile further comprises shadow areas between the pixels, and the electrical interconnection means is located in the shadow areas such that the electrical interconnection means does not block light transmitted by the pixels.

39. The large flat panel display of claim 38 in which the electrical interconnection means of the tile display module comprises lines which are as wide as possible, such that electrical delay is minimized.

40. The large flat panel display of claim 1 in which a plurality of layers of electrical interconnection means is applied to the back plate.

41. The large flat panel display of claim 40 in which the electrical interconnection means on the back plate comprise high conductivity metal traces deposited on at least one surface of the back plate.

42. The large flat panel display of claim 40 in which the tile display modules further comprise shadow areas between the pixels, and the electrical interconnection means is located in the shadow areas such that the electrical interconnection means do not block light transmitted by the pixels.

43. The large flat panel display of claim 42 in which the electrical interconnection means of the tile display module comprises lines which are as wide as possible, such that electrical delay is minimized.

44. The large flat panel display of claim 1 further comprising flowable alignment elements for connecting the pads of the tile display modules and the corresponding pads of the back plate, such that each of the tile display modules is both connected to the back plate and aligned relative to the other tile display modules by the action of the flowable alignment elements.

45. The large flat panel display of claim 44 in which the flowable alignment elements comprises solder joints which are liquefied and then solidify and draw the tile display module into alignment.

46. The large flat panel display of claim 45 in which the solder joints are made sufficiently small to fracture under tensional stress, such that the tile display module may be removed by lifting it outward relative to the back plate, fracturing the solder joints.

47. The large flat panel display of claim 1 further comprising a conductive adhesive for connecting the pads of the tile display modules and the corresponding pads of the back plate, such that each of the tile display modules is connected to the back plate physically and electrically by the conductive adhesive.

48. The large flat panel display of claims 47 in which the conductive adhesive connecting the pad of the tile display modules and the pad of the back plate is mechanically removable.

49. The large flat panel display of claim 1 further comprising a cover plate located over the tile display modules, covering the outer surface thereof.

50. The large flat panel display of claim 49 in which the cover plate is sealed to the back plate such that the tile display modules are contained within a sealed area comprising the gap between the cover plate and the back plate.

51. The large flat panel display of claim 50, further comprising a humidity control substance in the sealed area.

52. A large flat panel display comprising:

a) a plurality of tile display modules, each tile display module comprising;

i) a plurality of pixels arranged in a matrix having uniformly periodic interpixel spacing said pixels comprising an active area and an inactive, dark area,

ii) electrical interconnection means for addressing the pixels such that each pixel may be selectively controlled through the electrical interconnection means, and

iii) edge connection on at least one edge of the tile display module, connected to the electrical interconnection means;

b) a back plate for supporting the tile display modules, the tile display modules being mounted upon the back plate, located such that the interpixel spacing between two adjacent pixels on two adjacent tile display modules maintains the uniform periodicity of the interpixel spacing between adjacent pixels within the tile display modules, and such that the edge connection of each tile display module is located around the periphery of the display formed by the plurality of tile display modules;

c) driver means for driving the display modules, having connection means connected to the edge connection of the tile display modules such that the pixels of the tile display modules are operatively driven by the driver means; and

d) masking means disposed proximate said back plate, said shadow mask means preventing light entering said back plate from exiting in said dark areas of said pixels;

the pixels of the large flat panel display being addressed as if the large flat panel display comprising a plurality of tile display modules were a single monolithic large display.

53. The large flat panel display of claim 52, in which the tile display modules are mounted on the back plate using reworkable adhesive.

54. The large flat panel display of claim 52, in which:

the tile display modules further comprise a plurality of pads on the rear surface of the tile display modules;

the back plate further comprises a plurality of pads on the surface on which the tile display modules are mounted, located to match the pads on the rear surface of the tile display modules;

the flat panel display further comprises flowable passive alignment elements between the pads on the rear surface of the tile display modules and the pads on the back plate;

such that each of the tile display modules is both connected to the back plate and aligned relative to the other tile display modules by the flowable passive alignment elements.

55. The large flat panel display of claim 54 in which the flowable alignment elements comprise solder joints which are liquefied and then solidify and draw the display tile module into alignment.

56. The large flat panel display of claim 55 in which the solder joints are made sufficiently small to fracture under tensional stress, such that the tile display module may be removed by lifting it outward relative to the back plate, fracturing the solder joints.

57. A liquid crystal display module for use in tiled flat panel displays, comprising:

a) a first and a second plate, located in alignment, one below the other;

b) adhesive sealing means located between the first and second plates around the periphery of at least one of said plates, adhesively joining the first and second plates together and creating a volume therebetween, a gap being left in the adhesive sealing means forming an orifice, and the display module further comprising a notch in an edge thereof, aligned with the orifice;

c) liquid crystal material located in the volume between the first and second plates, the liquid crystal material being introduced between the first and second layers by evacuating the area between the first and second areas, introducing the liquid crystal through the orifice, then sealing the orifice, such that the seal in the orifice fits in the notch in the edge of the display module and does not extend beyond the edge;

d) a plurality of light valves arranged across the second plate with dark, shadow areas between the light valves, each light valve having a control input for controlling the light flow through the light valve, the control inputs being addressed through a matrix of row and column control lines, the spacing between light valves being uniformly periodic across the liquid crystal display module, the control lines being arranged in the dark, shadow areas between the light valves and forming a mask therein, said connecting lines connecting the plurality of light valves to the periphery of the liquid crystal display module, the width of the seal means being less than half the spacing between light valves; and

e) edge interconnection means for connecting the display module to a flat panel display, the edge interconnection means being located at the periphery of the display module, and connected to the control lines;

the adhesive seal means and the edge interconnection means being arranged such that when two modules are aligned in proximity to each other, the spacing between adjoining light valves on the two modules maintains a uniform periodicity with the spacing between light valves within the display module.

58. The liquid crystal display module of claim 57, in which the orifice is located in a position aligned with a shadow area between light valves.

59. The liquid crystal display module of claim 57, in which the sealing means is applied using a fine line dispensing needle.

60. The liquid crystal display module of claim 57, in which the edge interconnection means comprises pads located on the side of the second plate opposite the side to which the first plate is attached.

61. The liquid crystal display module of claim 60, in which the display module further comprises lead frame type connections having a first end connected to the control lines and a second end connected to the pad means, and the first end of the lead frame type connections has a plurality of nodules for enhancing contact between the lead frame and the control lines.

62. The liquid crystal display module of claim 61 in which the nodules are selected from the group consisting of palladium, nickel and gold.

63. The liquid crystal display module of claim 57 in which the adhesive is a conductive adhesive having conductive elements for connection to the control lines.

64. The liquid crystal display module of claim 57 in which the display module further comprises a ledge formed on the edge of at least one of the plates.

65. The liquid crystal display module of claim 64 in which the ledge is formed by extending one edge of one of the plates beyond the edge of the facing plate.

66. The liquid crystal display module of claim 64 in which the ledge is inset into one of the two plates, the edges of the two plates being coterminous.

67. The liquid crystal display module of claim 64 in which the display module further comprises connector means located within the ledge for electrical connection to the control lines.

68. The liquid crystal display module of claim 67 in which the display module further comprises lead frame type connections, having a first end connected to the connector means located in the ledge, and a second end connected to the edge connection means.

69. The display module of claim 68 in which the lead frame type connections are tape automated bonding connections.

70. The liquid crystal display module of claim 57 in which the edge interconnection means comprises means to wrap around from the first plate to the second plate, all within the shadow area.

71. The liquid crystal display module of claim 57 in which the edge interconnection means comprises a via filled with conductive material.

72. The liquid crystal display module of claim 57 in which the edge interconnection means comprises a metal trace applied to the edge of the liquid crystal display module.

73. The liquid crystal display module of claim 57 in which the first plate of the liquid crystal display module is coated on the side facing the second plate with a transparent conductive substance, and the liquid crystal display module further comprises:

f) at least one ground intraconnection pad formed on the surface of the second layer of the tile display module in a shadow area between light valves, connected to at least one electrical interconnection means on the second layer;

g) conductive means for connecting the conductive substance on the surface of the first layer and the ground intraconnection pad when the first and second layers are in alignment.

74. The liquid crystal display of claim 73 in which the conductive means is a conductive adhesive.

75. The liquid crystal display module of claim 73 in which the conductive means is a non-conductive spacer covered in conductive material.

76. The liquid crystal display module of claim 73 in which the transparent conductive substance is Indium Tin Oxide.