Large area tiled modular display system

• US 5,805,117 A
• Filed: 05/12/1994
• Issued: 09/08/1998
• Est. Priority Date: 05/12/1994
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Zammit, Theodore J., Maloney, Thomas C., Mazurek, Niel
• Primary Examiner(s): Mengistu, Amare
• Application Number:
  US08/241,599
• Time in Patent Office: 1,580 Days
• Field of Search: 345/1, 345/903, 345/102, 345/77, 248/917-919, 361/700, 361/392, 361/393, 361/394, 359/80, 359/83, 359/40, 348/383, 348/787, 348/779, 349/73, 349/109, 349/152, 349/158
• US Class Current: 345/1.3
• CPC Class Codes: G02F 1/13336 Combining plural substrates to produce large-area displays, e.g. tiled displays
• CPC Class Codes: G06F 3/147 using display panels
• CPC Class Codes: G09F 9/35 being liquid crystals G09F9/302 takes precedence; liquid crystal materials C09K19/00; liquid crystal panels comprising a number of electrodes in a single cell per se G02F1/13
• CPC Class Codes: G09G 2300/026 Video wall, i.e. juxtaposition of a plurality of screens to create a display screen of bigger dimensions
• CPC Class Codes: G09G 2360/04 Display device controller operating with a plurality of display units
• CPC Class Codes: H04N 5/70 Circuit details for electroluminescent devices
• CPC Class Codes: H04N 5/7441 the modulator being an array of liquid crystal cells
• CPC Class Codes: H04N 9/12 Picture reproducers H04N9/11 takes precedence
• CPC Class Codes: H04N 9/30 using solid-state colour display devices
• CPC Class Codes: Y10S 248/919 Adjustably orientable video screen support
• CPC Class Codes: Y10S 345/903 Modular display

Abstract

A tiled flat-panel modular display system includes an array of display modules which contain thin seal liquid crystal displays. Each one of a plurality of module alignment devices attach a respective display module to a large base plate. A frame is connected to the base plate and surrounds the base plate and display modules. A global cover glass assembly disposed above the display modules encloses and protects the display modules. Included in each of the display modules is a light source configuration of a light box and a light box cover which utilizes global light sources that provide efficient uniform backlighting of the corresponding display. The alignment devices permit alignment of the display modules with respect to each other and to a global black mask disposed in the global cover glass assembly to achieve a display system that is seamless in appearance. The tiled display system further utilizes compensation electronics to achieve uniform contrast and transmission characteristics in each of the thin seal displays. In addition, the display system utilizes display circuitry that achieves an improvement in optical performance over conventional displays.

Claims

1. A tiled display system comprising:

an array of display modules;

a base plate having a first major surface;

a plurality of module alignment devices, each one of the module alignment devices attaching a respective display module to the first major surface of the base plate and providing vertical and horizontal adjustment capability to the respective display module; and

a global cover glass assembly disposed above the display modules.

2. The display system of claim 1 further comprising:

a rear plate connected to a second major surface of the base plate; and

a housing connected to the rear plate and surrounding the base plate and display modules, wherein the display modules are protected by the housing and the global cover glass assembly.

3. The display system of claim 1, wherein each one of the display modules comprises:

a light box having a first open side and paired holes on opposite side walls, with global light sources extending into and through the light box through the paired holes;

a substantially transparent light box cover positioned adjacent the front open side of the light box; and

a thin seal display panel being positioned proximate a side of the light box cover opposite the light box light box, the thin seal display containing an array of picture elements and electrical edge contacts.

4. The display system of claim 3, wherein the light box cover spreads a portion of light generated by the global light sources to edge regions of the light box cover that extend parallel to a direction of the light sources in order to substantially balance the light output across the front surface of the light box cover.

5. The display system of claim 4, wherein the light box cover front surface is substantially flat and positioned adjacent the thin seal display, a back surface of the light box cover is positioned adjacent the light box, the back surface having concave surfaces in the edge regions to spread the light generated by the light sources.

6. The display system of claim 5, wherein the light box cover further comprises beveled edges in the edge regions extending parallel to the direction of the light sources.

7. The display system of claim 6, wherein an angle formed by an edge surface of the beveled edges with respect to the adjacent light box sidewalls is on the order of 50 degrees.

8. The display system of claim 3, wherein surfaces of the light box have a substantially white color.

9. The display system of claim 3 further comprising:

a driver circuit board containing display driver circuits, the driver circuit board being disposed on a rear side of the light box opposite the front open side; and

at least one thin electrical conductor connecting the thin seal display electrical edge contacts to the display driver circuits.

13. The display system of claim 9, wherein boundary picture elements of the array of picture elements adjacent edges of the thin seal display are disposed a particular distance from the edges such that when a similar display module is positioned adjacent the display module, spacing between corresponding boundary picture elements of the display modules is substantially identical to spacing between respective adjacent picture elements in the array of picture elements within one of the same display modules to produce a tiled display system having a seamless appearance.

17. The display system of claim 3, wherein the display module further comprises a patterned light diffuser positioned adjacent the front surface of the light box cover to provide substantially uniform luminance to the thin seal display.

18. The display system of claim 17, wherein the patterned diffuser comprises:

a translucent sheet;

a plurality of shaded regions, each one of the regions corresponding to positions of the picture elements in the thin seal display, and containing a particular amount of a shading based on luminance output of a portion of the light box cover corresponding to that region.

19. The display system of claim 18, wherein the particular amount of shading consists of various densities of dots.

20. The display system of claim 1, wherein the global cover glass assembly comprises:

a transparent plate having first and second major surfaces; and

a global diffusion mask disposed on the first major surface of the transparent plate.

21. The display system of claim 20, wherein the global cover glass assembly further comprises a global black mask disposed on the second major surface of the transparent plate.

23. The display system of claim 1, wherein the global cover glass assembly is a frosted glass plate.

24. The display system of claim 1, wherein each one of the alignment devices is attached to a second major surface of the base plate and to the respective one of the display modules adjacent the first major surface of the base plate by a post extending through a corresponding hole in the base plate, wherein each one of the alignment devices is capable of moving the respective display module in a horizontal and a vertical direction relative to the other display modules.

25. The display system of claim 24, wherein each alignment device comprises:

an outer retainer;

an inner retainer contained within the outer retainer, the inner retainer being attached to the post that is fixed to the corresponding display module;

vertical and horizontal screw adjuster assemblies which are cable of providing a force on the inner retainer in the vertical and horizontal directions; and

a spring for providing a biasing force on the inner retainer in directions opposite to the forces generated by the screw adjusters.

27. The display system of claim 24, further comprising compression devices attached to each one of the display modules and the base plate to provide a compression force to hold the display modules against the base plate in order to maintain alignment of the display module and to permit thermal expansion or contraction of the display module relative to the base plate.

28. The display system of claim 27, wherein each one of the compression devices comprises:

a screw having a head and an end, the screw end being attached to the display module and extending through a hole in the base plate such that the screw head is adjacent the second major surface of the base plate; and

an extension coil spring positioned between the screw head and to the base plate proximate the corresponding hole such that the display module is forced in a direction toward the first major surface of the base plate.

29. The display system of claim 1 further comprising:

a contrast adjustment circuit having a plurality of outputs, each one of the outputs being connected to a voltage input of a respective display module, wherein the contrast adjustment circuit is capable of varying the voltage applied to the display module voltage inputs to adjust the contrast and transmission characteristics of each one of the thin seal displays such that each one of the thin seal displays has substantially similar brightness and contrast characteristics.

30. The display system of claim 29, wherein the contrast adjustment circuit comprises:

a processing unit;

a plurality of controllable potentiometers having a plurality of inputs and corresponding outputs, the electrical resistance between the inputs and outputs of the controllable potentiometers being controlled by signals received from the processing unit, each one of the outputs of the controllable potentiometers being connected to a corresponding voltage input of the display modules; and

a power supply connected to the plurality of controllable potentiometers, wherein the processing unit is capable of controlling the electrical resistance of the potentiometers to vary the voltage applied to the display modules.

10. A tiled display system comprising:

an array of display modules;

a base plate having a first major surface;

a plurality of module alignment devices, each one of the module alignment devices attaching a respective display module to the first major surface of the base plate; and

a global cover glass assembly disposed above the display modules, wherein each one of the display modules comprises;

a light box having a first open side and paired holes on opposite side walls, wherein global light sources can extend into and through the light box through the paired holes;

a substantially transparent light box cover positioned adjacent the front open side of the light box; and

a thin seal display panel being positioned proximate a side of the light box cover opposite the light box light box, the thin seal display containing an array of picture elements and electrical edge contacts, wherein the thin seal display comprises;

first and second substrates having major surface areas of the substantially the same size;

a liquid crystal material disposed between major surfaces of the first and second substrates; and

the thin seal attaching the first and second substrate together and containing the liquid crystal material, the thin seal having a uniform interior edge and an outer edge, the outer edge being substantially in alignment with edges of the first and second substrates, the thin seal being formed by a precision reduction of the substrate edges and seal until the seal is the desired width of the thin seal, wherein the array of picture elements are disposed in a display area formed by sealed area, and the electrical edge contacts, which are electrically connected to the picture elements, are disposed on the edges of the substrates.

11. The display system of claim 10, wherein the array of picture elements are passive matrix picture elements and wherein each picture element is formed by an intersection of row and column conductors electrically connected to the electrical edge contacts.

12. The display system of claim 10, wherein the array of picture elements are active matrix picture elements.

14. The display system of claim 10 further comprising a color filter mask positioned adjacent the thin seal display wherein the color filter mask provides sufficient coloration of the picture elements to produce a colored display.

15. The display system of claim 14, wherein the color filter mask contains groups of tinted red, green and blue color stripes which are positioned in accordance with respective groups of three picture elements forming respective pixels, and which are slightly wider than a width of the corresponding picture elements.

16. The display system of claim 15, wherein the color stripes and pixels are arranged in a horizontal orientation to improve the horizontal viewing angle.

22. A tiled display system comprising:

an array of display modules;

a base plate having a first major surface;

a plurality of module alignment devices, each one of the module alignment devices attaching a respective display module to the first major surface of the base plate; and

a global cover glass assembly disposed above the display modules, wherein the global cover glass assembly comprises;

a transparent plate having first and second major surfaces;

a global diffusion mask disposed on the first major surface of the transparent plate;

a global black mask disposed on the second major surface of the transparent plate, wherein the global black mask comprises;

a transparent sheet; and

an array of row and column opaque strips positioned such that transparent mask openings formed by the opaque stripes correspond to the size, shape and positions of the pixels, wherein the opaque stripes mask the regions between pixels on each of the display modules and between boundary pixels of adjacent display modules to produce the tiled display system that is seamless in appearance.

26. A tiled display system comprising:

an array of display modules,

a base plate having a first major surface;

a plurality of module alignment devices, each one of the module alignment devices attaching a respective display module to the first major surface of the base plate; and

a global cover glass assembly disposed above the display modules, wherein each one of the alignment devices is attached to a second major surface of the base plate and to the respective one of the display modules adjacent the first major surface of the base plate by a post extending through a corresponding hole in the base plate, wherein each one of the alignment devices is capable of moving the respective display module in a horizontal and a vertical direction relative to the other display modules, wherein each alignment device comprises;

an outer retainer;

an inner retainer contained within the outer retainer, the inner retainer being attached to the post that is fixed to the corresponding display module;

vertical and horizontal screw adjuster assemblies which are cable of providing a force on the inner retainer in the vertical and horizontal directions; and

a spring for providing a biasing force on the inner retainer in directions opposite to the forces generated by the screw adjusters, wherein each one of the vertical and horizontal screw adjusters comprises;

a screw having a head and an end;

a corresponding screw end cap attached to the screw end;

a captured wedge-shaped block having a threaded through hole; and

a free wedge-shaped block, wherein the screw extends through a first hole in the outer retainer, the threaded screw hole of the captured block and second hole in the outer retainer, the screw end being located outside of the outer retainer and is capped by the screw end cap such that the screw may be rotated within the outer retainer to move the captured block forward or backward relative to the screw, an angled edge surface of the captured block engages an angled edge surface of the free block to exert a force orthogonal to the direction of movement of the captured block, the force acting against the spring to move the inner retainer forward or backward in the direction of the created force.

31. A tiled display system comprising:

array of display modules;

a base plate having a first major surface;

a plurality of module alignment devices, each one of the module alignment devices attaching a respective display module to the first major surface of the base plate;

a global cover glass assembly disposed above the display modules; and

an interface circuit capable of producing an image on the tiled display system based on driver signals received by the display system, wherein the interface circuit comprises;

a first switch having an input and first and second outputs;

first and second memory units, each memory unit having an input and a plurality of sector information outputs and being capable of storing a frame of display information, the inputs of the first and second memory units being connected to the corresponding first and second outputs of the first switch, wherein row and column information in the driver signals being applied to the first switch input is directed to the first memory unit input when the first switch is in a first position and to the second memory unit input when the first switch is in a second position;

a second switch having a plurality of outputs and a plurality of corresponding first and second inputs, the plurality of first and second inputs being connected to corresponding sector information outputs of the frame memory units, wherein when in a first position the second switch connects the first frame memory unit outputs to the outputs of the second switch or when in a second position the second switch connects the second frame memory unit outputs to the output of the second switch;

a plurality of video subcontrollers, each subcontroller connected to at least one of the plurality of outputs of the second switch and controlling a corresponding sector of the array of thin seal displays in the tiled display system; and

a timing control circuit receiving the driver signals and controlling the positions of the first and second switches such that a frame of the row and column display information is sequentially alternatively provided to and stored in the first and second frame memory units while the information sector outputs of the frame memory unit not receiving the driver signals is connected to the subcontrollers, wherein the memory units are capable of providing information for each sector to the corresponding subcontrollers at substantially the same time such that each sector of the array of thin seal displays are updated at substantially the same time.

32. The display system of claim 31, wherein the interface circuit further comprises:

at least one shift register connected to a corresponding one of the subcontrollers and to corresponding rows of picture elements in the sector; and

row select inputs of a sector of display modules connected to the subcontrollers, wherein each one of the subcontrollers is capable of sequentially providing a picture element for each row of the sector to the shift register and sequentially activating each corresponding row of sector picture elements by the row select inputs to activate all the picture elements in the sector to form the display image.

33. A display module for use in a tiled modular display system comprising:

a light box having a first open side and paired holes on opposite side walls, with global light sources extending into and through the light box through the paired holes;

a substantially transparent light box cover positioned adjacent the front open side of the light box; and

a thin seal display panel being positioned proximate a side of the light box cover opposite the light box, the thin seal display containing an array of picture elements and electrical edge contacts.

34. The display module of claim 33, wherein the light box cover spreads a portion of light generated by the global light sources to edge regions of the light box cover that extend parallel to a direction of the light sources in order to substantially balance the light output across the front surface of the light box cover.

35. The display module of claim 34, wherein the light box cover front surface is substantially flat and positioned adjacent the thin seal display, a back surface of the light box cover is positioned adjacent the light box, the back surface having concave surfaces in the edge regions to spread the light generated by the light sources.

36. The display module of claim 35, wherein the light box cover further comprises beveled edges in the edge regions extending parallel to the direction of the light sources.

37. The display module of claim 36, wherein an angle formed by respective edge surfaces of the beveled edges with respect to the corresponding adjacent light box sidewalls is on the order of 50 degrees.

38. The display module of claim 33, wherein surfaces of the light box have a substantially white color.

39. The display module of claim 33 further comprising:

a driver circuit board containing display driver circuits, the driver circuit board being disposed on a light box back side opposite the front open side; and

at least one thin electrical conductor connecting the thin seal display electrical edge contacts to the display driver circuits.

46. The display module of claim 33, wherein the display module further comprises a patterned light diffuser positioned adjacent the front surface of the light box cover to provide substantially uniform luminance to the thin seal display.

47. The display module of claim 46, wherein the patterned diffuser comprises:

a translucent sheet;

a plurality of shaded regions, each one of the regions corresponding to positions of the picture elements in the thin seal display, and containing a particular amount of a shading based on luminance output of a portion of the light box cover corresponding to that region.

48. The display module of claim 47, wherein the particular amount of shading consists of various densities of dots.

40. A display module for use in a tiled modular display system comprising:

a light box having a first open side and paired holes on opposite side walls, wherein global light sources can extend into and through the light box through the paired holes;

a substantially transparent light box cover positioned adjacent the front open side of the light box; and

a thin seal display panel being positioned proximate a side of the light box cover opposite the light box, the thin seal display containing an array of picture elements and electrical edge contacts, wherein the thin seal display comprises;

first and second substrates having major surface areas of the substantially the same size;

a liquid crystal material disposed between major surfaces of the first and second substrates; and

a thin seal attaching the first and second substrate together and containing the liquid crystal material, the thin seal having a uniform interior edge and an outer edge, the outer edge being substantially in alignment with edges of the first and second substrates, the thin seal being formed by a precision reduction of the substrate edges and seal until the seal is the desired width of the thin seal, wherein the array of picture elements are disposed in a display area formed by sealed area, and the electrical edge contacts, which are electrically connected to the picture elements, are disposed on the edges of the substrates.

41. The display module of claim 40, wherein the array of picture elements are passive matrix picture elements and wherein each picture element is formed by an intersection of row and column conductors electrically connected to the electrical edge contacts.

42. The display module of claim 40, wherein boundary picture elements of the array of picture elements adjacent edges of the thin seal display are disposed a particular distance from the edges such that when a similar display module is positioned adjacent the display module, spacing between corresponding boundary picture elements of the display modules is substantially identical to spacing between adjacent respective picture elements in the array of picture elements within one of the same display modules to produce a tiled display system having a seamless appearance.

43. The display module of claim 40 further comprising a color filter mask positioned adjacent the thin seal display wherein the color filter mask provides sufficient coloration of the picture elements to produce a colored display.

44. The display module of claim 43, wherein the color filter mask contains groups of tinted red, green and blue color stripes which are positioned in accordance with respective groups of three picture elements forming respective pixels and which are slightly wider than a width of the corresponding picture elements.

45. The display module of claim 44, wherein the color stripes and pixels are arranged in a horizontal orientation to improve the horizontal viewing angle.

49. A light source configuration for providing a substantially uniform luminance output to a display module in a tiled modular display system comprising:

a light box having a first open side and paired holes on opposite side walls such that global light sources may extend into and through the light box through the paired holes;

a substantially transparent light box cover positioned adjacent the front open side of the light box, wherein the light box cover spreads a portion of light generated by the light sources to edge regions of the light box cover that extend parallel to a direction of the light sources in order to improve the balance of the light output across the front surface of the light box cover.

50. The light source configuration of claim 49, wherein the light box cover front surface is substantially flat and adjacent the thin seal display, a back surface of the light box cover is positioned adjacent the light box, the back surface having concave surfaces in the edge regions to spread the light generated by the light sources.

51. The light source configuration of claim 50, wherein the light box cover further comprises beveled edges in the edge regions extending parallel to the direction of the light sources.

52. The light source configuration of claim 51, wherein an angle formed by respective edge surfaces of the beveled edges with respect to the corresponding adjacent light box sidewalls is on the order of 50 degrees.

53. The light source configuration of claim 49, wherein surfaces of the light box have a substantially white color.

54. A display module alignment device for securing and aligning a display module in a tiled modular display system comprising:

an outer retainer;

an inner retainer contained within the outer retainer, the inner retainer being attached to the post that is fixed to the corresponding display module;

vertical and horizontal screw adjuster assemblies which are capable of providing a force on the inner retainer in the vertical and horizontal directions; and

a spring for providing a biasing force on the inner retainer in directions opposite to the forces generated by the screw adjusters.

55. A display module alignment device for securing and aligning a display module in a tiled modular display system comprising:

an outer retainer;

an inner retainer contained within the outer retainer, the inner retainer being attached to the post that is fixed to the corresponding display module;

vertical and horizontal screw adjuster assemblies which are capable of providing a force on the inner retainer in the vertical and horizontal directions; and

a spring for providing a biasing force on the inner retainer in directions opposite to the forces generated by the screw adjusters, wherein each one of the vertical and horizontal screw adjusters comprises;

a screw having a head and an end;

a corresponding screw end cap attached to the screw end;

a captured wedge-shaped block having a threaded through hole; and

a free wedge-shaped block, wherein the screw extends through a first hole in the outer retainer, the threaded screw hole of the captured block and a second hole in the outer retainer, the screw end being located outside of the outer retainer and is capped by the screw end cap such that the screw may be rotated within the outer retainer to move the captured block forward or backward relative to the screw, an angled edge surface of the captured block engages an angled edge surface of the free block to exert a force orthogonal to the direction of movement of the captured block, the force acting against the spring to move the inner retainer forward or backward in the direction of the created force.

56. An interface circuit capable of producing an image on a tiled display system based on driver signals received by the display system, the interface circuit comprising:

a first switch having an input and first and second outputs;

first and second memory units, each memory unit having an input and a plurality of sector information outputs and being capable of storing a frame of display information, the inputs of the first and second memory units being connected to the corresponding first and second outputs of the first switch, wherein row and column information in the driver signals being applied to the first switch input is directed to the first memory unit input when the first switch is in a first position and to the second memory unit input when the first switch is in a second position;

a second switch having a plurality of outputs and a plurality of corresponding first and second inputs, the plurality of first and second inputs being connected to corresponding sector information outputs of the frame memory units, wherein when in a first position the second switch connects the first frame memory unit outputs to the outputs of the second switch or when in a second position the second switch connects the second frame memory unit outputs to the output of the second switch;

a plurality of video subcontrollers, each subcontroller connected to at least one of the plurality of outputs of the second switch and controlling a corresponding sector of the array of displays in the tiled display system; and

a timing control circuit receiving the driver signals and controlling the positions of the first and second switches such that a frame of the row and column display information is sequentially alternatively provided to and stored in the first and second frame memory units while the information sector outputs of the frame memory unit not receiving the driver signals is connected to the subcontrollers, wherein the memory units are capable of providing information for each sector to the corresponding subcontrollers at substantially the same time such that each sector of the array of thin seal displays are updated at substantially the same time.

57. The interface circuit of claim 56 further comprising:

at least one shift register connected to a corresponding one of the subcontrollers and to corresponding rows of picture elements in the sector; and

row select inputs of a sector of display modules connected to the subcontrollers, wherein each one of the subcontrollers is capable of sequentially providing pixel information for each row of the sector to the shift register and sequentially activating each corresponding row of sector pixels by the row select inputs to activate all the pixels in the sector to form the display image.

58. A method of generating a patterned light diffuser for a light source configuration comprising the steps of:

detecting the luminance output of particular regions across the light source configuration;

generating luminance output values corresponding to the luminance output detected for the detected regions;

identifying the lowest luminance output value;

generating respective correction values corresponding to the difference between the generated luminance output values and the identified lowest luminance output value; and

shading areas on a transparent sheet corresponding to the detected regions of the light source configuration, the amount of shading being dependent on the respective generated correction values.

59. The method of claim 58, wherein the step of shading areas comprises generating various densities of dot patterns.

60. The method of claim 59, wherein generation of the dot patterns comprises the steps of:

generating formatted shading printer information based on the generated correction values; and

printing on the transparent shading areas based on the formatted information.