Seamless tiled active matrix liquid crystal display

• US 20020118321A1
• Filed: 04/08/2002
• Published: 08/29/2002
• Est. Priority Date: 03/12/1998
• Status: Abandoned Application

• Current Assignee: Shichao Ge
• Original Assignee: Shichao Ge
• Inventors: Ge, Shichao
• Application Number:
  US10/119,138
• Publication Number:
  US 20020118321A1
• Time in Patent Office: Days
• US Class Current: 349/73
• CPC Class Codes: G02F 1/133305 Flexible substrates, e.g. plastics, organic film
• CPC Class Codes: G02F 1/13336 Combining plural substrates to produce large-area displays, e.g. tiled displays

Abstract

A seamless tiled display employs active liquid crystal display (LCD) and backlight. The active matrix elements of active LCD are mounted on the inside or outside of the front plate or back plate of LCD. A thin front plate and a thin sealing wall are used to reduce the seam width of the tiled LCD. A laser cutting is used for a thin LCD sealing. A spacer added adhesive array is deposited between pixels and between front plate and back plate to guarantee the uniformity of LC cells thickness. A laser riveting is still used for making a robust plastic LCD. A reflective layer is deposited on the side wall of back plate to reflect the light emitted from the backlight and to reduce the apparent seam width. In the backlight, there can be at least one set of red, green and blue light source operated at color sequential mode to display a color image without the use of color filters.

Claims

1. A tiled active liquid crystal display device, comprising a plurality of LCD tiles, each tile comprising:

an active matrix liquid crystal display, said display having a thin front plate and liquid crystal (LC) cells;

a backlight with a light source;

means for applying the signals to said display to modulate transmittance of the liquid crystal (LC) cells, and of light from the backlight transmitted by said LC cells to display an image;

said device further comprising means assembling said LCD tiles to form a super-large-screen display.

2. The device of claim 1, wherein thickness of said thin front plate is in the range of about 0.02 to 0.7 mm.

3. The device of claim 1, wherein each of at least some of said LCD tiles has an outside active matrix control device mounted on an outside surface of such LCD tile.

4. The device of claim 3, wherein said outside active matrix control device is a field effect transistor, bipolar transistor, diode or varistor.

5. The device of claim 3, wherein said outside active matrix control device controls one LC cell or one group of LC cells.

6. The device of claim 1, wherein said light source is a cold cathode fluorescent lamp (CCF), hot cathode fluorescent lamp (HCFL) or light emitting diode (LED).

7. The device of claim 1, wherein said light source includes a white light source, and a color filter array on surfaces of said LCD tiles to display a multi-color or full-color image or characters etc.

8. The device of claim 1, wherein said light source comprises at least one set of red, green, blue (R, G, B) CCFLs or LEDs, and wherein said applying means causes said tiled LCD to be operated at a color sequential mode to display a full-color image or characters.

9. The device of claim 1, wherein said light source includes a driver for controlling light intensity, said driver including a brightness adjustment circuit for adjusting the brightness of said light source manually or automatically, to adjust brightness in order to enhance brightness uniformity across the LCD tiles.

10. A seamless active tiled LCD device, comprising:

a LCD with a thin front plate, a sealing side wall and a back plate, said LCD having a LC layer and pixels;

a thin sealing cover over the thin sealing wall of the LCD; and

an adhesive array having at least one spacer between the pixels and between the front and back plates to enhance thickness uniformity of the LC layer in the LCD.

11. The device of claim 10, wherein said front plate and back plate comprises a transparent substrate, said substrate including glass or plastic.

12. The device of claim 10, wherein said front plate and sealing wall form an integral piece or are two separate pieces.

13. The device of claim 10, wherein said outside sealing cover, which is an anti-reflective plate, a transparent or diffusing plate, or having the optical function to change the light direction, i.e. to change the viewing angle, e.g., micro-lens plate or holographic plate and the like.

14. The device of claim 10, wherein said LCD is an active LCD, the active matrix devices are mounted on the interior surface of the substrate of LCD or mounted on the outside of the substrate of LCD.

15. The device of claim 10, wherein a series of conductive pins hidden in the plate to connect the electrodes of LC cells and outside circuits to guarantee the reliability of the electric connection.

20. The device of claim 19, further comprising a diffusing front plate, the first surface of said chamber being a surface of the diffusing front plate;

and

means connecting said diff-using plate to the thin LCD tiles and to said backlight so that such plate is between the tiles and the backlight.

21. The device of claim 20, wherein said diffusing front plate includes a brightness enhancement film.

22. The device of claim 20, wherein said spacer is mounted on said diffusing front plate with transparent adhesive to obtain a shadowless backlight.

23. The device of claim 19, further comprising one or more optical plates adjacent to the tiles, said optical plate having the function of anti-reflection, diffusing, contrast enhancement or/and viewing angle changing.

24. The device of claim 23, wherein said front optical plate can be one piece for one screen or one piece for one tile.

25. The device of claim 19, wherein said at least one light source comprises at least one hot cathode fluorescent lamp, cold cathode fluorescent lamp or light emitting diode.

26. The device of claim 19, wherein each of at least some of said LCD tiles comprises a thin front plate and a thin back plate, wherein the thicknesses of these plates are in the range of about 0.02 to 5 mm.

27. The device of claim 19, wherein each of said LCD tiles is a transmissive LCD, reflective LCD or scattering LCD.

28. The device of claim 19, wherein each of at least some of said LCD tiles has LC cells a spacer mixed adhesive array located between said the front plate and back plate to keep the LC cells uniform in the whole tile.

29. The device of claim 19, wherein said LCD tile is an outside-active-matrix (OAM) LCD, including an active control device that includes a field effect transistor, bipolar transistor, diode, or varistor.

30. The device of claim 29, wherein said OAM device is at least one chip, one chip has at least one active device to control the related LC cell.

31. The device of claim 19, wherein said seamless tiled LCD is a color LCD, and a color filter array and a black matrix are deposited on the inside surface or outside of said thin front plate or back plate of said LCD tiles.

32. The device of claim 27, wherein said spacer mixed adhesive is still deposited at OAM mounted area between said thin front plate and thin back plate to increase the mechanical strength.

33. The device of claim 19, wherein said connector is made of a transparent substrate and at least one conductive means is deposited, and used for connecting the electrodes of the tiles between the adjacent tiles.

34. The device of claim 19, wherein said connectors have auxiliary electrical connectors, which are connected in parallel with the related column electrodes, row electrodes and the common electrodes to reduce the resistance of the electrodes and to increase the reliability of the connections.

37. The LCD of claim 36, further comprising a front optical plate, which has the function of anti-reflection, diffusing, contrast enhancement or/and viewing angle changing;

40. The device of claim 39, wherein said light source is HCFL, CCFL or LED.

41. The device of claim 39, wherein said front diffusing plate and transparent back plate have the same or similar coefficient of thermal expansion.

42. The device of claim 39, wherein said front diffusing plate and transparent back plate can be one piece plate or combined of two or more pieces plates.

43. The device of claim 39, wherein said spacer is a cone shape spacer or other shape spacer, and fixed on the inside surface of the front diffusing plate by transparent adhesive.

44. The device of claim 39, wherein a diagonal dimension of the backlight is not less than 20 inches.

46. The device of claim 45, wherein a diagonal dimension of the backlight is not less than 20 inches.

47. The device of claim 45, wherein a series of conductors are deposited on the outside of the front diffusing plate of said backlight, used for connecting tiles and connecting tiles to the driving electronics of the display system.

50. The device of claim 49, wherein said LCD can be a transmissive LCD, reflective LCD or scattering LCD.

51. The device of claim 49, wherein said rivet is a through hole drilling by laser beam, and along the hole has a thin sealing wall formed by the melted plastic, and formed the rivet.

52. The device of claim 49, wherein said back plastic plate is thinner than said front plastic plate. The laser drilling is started from the back plate using a small diameter laser beam. The laser beam do not make a through hole, the drilling is stopped at both of front plate and back plate are melted and attached together, and to form the rivet. This structure and process can be used for making the high resolution plastic LCD, and can be used for making mosaic LCD and single piece LCD.

53. The device of claim 49, wherein said back plastic plate and said back plate are a plastic film, e.g. polyester, polycarbinate or other plastic film.

16. A tiled,.transparent LCD, comprising:

a transmissive LCD having a back plate with a side wall, and a reflective layer on the side wall of the back plate; and

a backlight;

said reflective layer reflecting light emitted from the backlight to reduce the apparent seam width of the LCD.

17. A tiled reflective LCD, comprising:

a transmissive LCD having a back plate with a side wall, and a reflective layer on the side wall of the back plate; and

a reflector located near the back plate of the LCD;

said reflective layer reflecting light reflected by the back reflector to reduce the apparent seam width of the tiled display.

18. A tiled active LCD display system comprising:

a display screen having N by M thin seamless active LCD tiles;

each tile having at least one backlight with a light source and driver and at least one connector;

a driving and control circuit;

wherein all tiles are connected to said circuit through said connector;

means for applying voltage and signals to the driving and control circuit and tiles to display information and images according to the signals.

19. A seamless tiled LCD, comprising:

a good mechanical strength backlight, which serves as a base plate of a display screen, said backlight comprising;

(a) at least one light source;

(b) a reflective chamber having a first and a second opposing surface and housing said light source, said first surface being flat;

(c) a good mechanical strength frame holding said chamber and said diffusing front plate;

at least one transparent spacer located between the opposing surfaces of said reflective chamber to maintain the flat shape of said first surface;

at least two thin LCD tiles, said tiles connected to the first surface so that they are supported by the first surface, said tiles having electrodes; and

at least one set of connectors located between said tiles to connect the electrodes of adjacent tiles.

35. A light utilization improved structure comprises:

a reflective '"'"'matrix is deposited on the outside surface of the front plate of the backlight or on the outside surface of said thin back plate, said reflective matrix can reflect the light, which emitting to black matrix and could being absorbed by black matrix, to the backlight reflector to increase the light utilization factor of the backlight.

36. A seamless tiled LCD, comprising:

a good mechanical strength reflector, which is as a base plate of the display screen, and comprises of diffusing reflective plate or a mirror and a good mechanical strength frame.

at least two thin LCD tiles, said LCD tiles are mounted on the outside surface of said diffusing front plate;

at least one set of connector located between said tiles to connect the electrodes of the adjacent tiles; and

means mounting said thin LCD tiles on a good mechanical strength reflector, to form a thin profile, light weight and very strong large screen display.

38. A sealing method for thin sealing wall LCD sealing, which comprises

a spacer mixed adhesive is deposited at the sealing area, e.g. by printing, between said thin front plate and thin back plate, then cured;

cutting by laser along the sealing wall;

means using laser cutting to form a very thin sealing wall, because the thin front plate and thin back plate will be melted during laser cutting. At the same time, at said cutting area still has sealing adhesive, different sealing wall can be obtained depending on sealing adhesive pattern design;

the width of sealing wall van be range of 0.01 to 10 mm.

39. A large screen spacer-shadowless backlight, comprising:

at least one light source;

one front diff-using plate and one transparent back plate;

at least one transparent spacer located between said front diffusing plate and transparent back plate;

a side wall located at the four sides of the front diffusing plate and the transparent back plate and between said plates;

a reflective layer located at the outside of the back plate and the side wall to form a reflective chamber;

a good mechanical strength frame;

means the front diffusing plate, the transparent back plate, spacer, side wall, reflective layer and mechanical frame forming a large screen spacer-shadowless good mechanical strength backlight.

45. A tiled LCD, comprising:

a large screen spacer-shadowless backlight;

at least two thin LCD tiles;

means mounting the tiles on the outside surface of the front diffusing plate of said backlight to form a tiled LCD.

48. A sealing method for plastic LCD sealing, which comprises a front plastic plate and a back plastic plate, which with electrodes and other LCD parts, and aligned each other and fixed;

cutting by laser along the sealing area;

means using laser cutting to form a thin sealing wall at sealing area, because the front plate and back plate will be melted during laser cutting at sealing area, and a thin sealing wall will be formed. The width of the sealing wall can be range of 0.01 to 10 mm.

49. A riveted plastic LCD, which comprises

a front plastic plate and a back plastic plate, which with electrodes and other LCD parts, and aligned each other and fixed;

at least one rivet made by laser beam to melt said front plate and said back plate to form the rivet;

means making at least one rivet, riveting said front plate and said back plate to form a robust plastic LCD.