Tiled, flat-panel microdisplay array having visually imperceptible seams

• US 6,005,649 A
• Filed: 07/22/1998
• Issued: 12/21/1999
• Est. Priority Date: 07/22/1998
• Status: Expired due to Term

• Current Assignee: Hanger Solutions, LLC (IP Investments Group LLC)
• Original Assignee: Rainbow Displays, Inc.
• Inventors: Seraphim, Donald P., Krusius, J. Peter
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): CHOWDHURY, TARIFUR RASHID
• Application Number:
  US09/120,569
• Time in Patent Office: 517 Days
• Field of Search: 349/73, 349/74, 349/20, 349/21
• US Class Current: 349/73
• CPC Class Codes: G02F 1/13336 Combining plural substrates to produce large-area displays, e.g. tiled displays
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• 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 2320/041 Temperature compensation
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters

Abstract

This invention describes tiling structures, methods, and circuits for making large flat-panel displays from an array of microdisplays. The inventive displays overcome the intrinsic size limits of monolithic microdisplays and allow the construction of large area, low cost, high brightness, high contrast magnified view or rear projection flat panel displays having visually imperceptible seams and are optically uniform. A structure wherein multiple microdisplay tiles are mounted on a thermally matched common substrate having inherent temperature control features is described. Additional integrated circuits such as CMOS circuits may be embedded either in the back plane of the microdisplay tiles themselves and/or in the common substrate if the common substrate is made from a suitable semiconductor material. These circuits can provide functions such pixel addressing, image control, or even complete microprocessor functions within the flat-panel display assembly itself.

Claims

1. A tiled, substantially flat, panel display comprising a plurality of microdisplays, each of said microdisplays being capable of displaying no less than a 640×

480 array of pixels at a pixel pitch no greater that approximately 30 μ

m and occupying a space no greater than about 45×

55 mm, said display having the characteristic of visually imperceptible seams between microdisplays disposed in an interior portion thereof, such that said panel display can be viewed as though it were a single, monolithic display, comprising;

a) a plurality of adjacently disposed microdisplays, said microdisplays comprising a non-transparent stack having an embedded integrated circuit, and having spaced-apart, reflective pixel-active areas upon which are formed at least a segment of an image, said segment of an image being combinable into a complete image at a view plane, said pixel-active areas being disposed at a predetermined pitch, each of said microdisplays having a predetermined thickness, disposed on a substrate adjacent and substantially parallel to said reflective pixel-active areas, said microdisplays and said substrate comprising a microdisplay assembly;

b) means defining seams disposed between adjacent microdisplays;

c) means for illuminating said image formation plane;

d) light absorbing means proximate said seams so that light directed to said seams is substantially absorbed, thereby rendering said seams substantially visually imperceptible to a viewer; and

e) means for enlarging and projecting said image segments into said view plane, with substantially no visually perceptible discontinuities between said enlarged image segments.

2. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 1, wherein said light absorbing means is applied uniformly between said pixel-inactive areas.

3. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 1, wherein said means for projecting said image comprises means for magnifying said image.

4. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 1, wherein said substrate has thermal and mechanical characteristics substantially matching the thermal and mechanical characteristics of said microdisplays.

5. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 4, wherein said substrate comprises heat transfer means for transporting dissipated heat from said microdisplays in order to maintain substantial thermal uniformity over all of said microdisplays.

6. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 5, wherein said heat transfer means comprises at least one from the group of heat sink, embedded microcooling channel, and heat pipe.

7. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 1, further comprising thermal control means for regulating temperature of said microdisplay assembly.

8. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 7, wherein said thermal control means for regulating temperature of said microdisplay assembly comprises heat generating means.

9. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 1, wherein said substrate comprises at least one from the group of silicon and glass ceramic.

10. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 1, wherein said substrate comprises semiconductor material having thermal and mechanical characteristics substantially matching the thermal and mechanical characteristics of said microdisplays.

11. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 10, wherein said substrate comprises heat transfer means for transporting dissipated heat from said microdisplays in order to maintain substantial thermal uniformity over all of said microdisplays.

12. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 11, wherein said heat transfer means comprises at least one from the group of heat sink, embedded microcooling channel, and heat pipe.

13. The tiled, substantially flat, display panel composed of a plurality of microdisplays in accordance with claim 12, further comprising a light shield disposed in said seams for blocking light from entering said integrated circuits.

14. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 11, wherein said integrated circuit comprises a CMOS structure.

15. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 10, wherein said substrate comprises an integrated circuit.

16. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 10, wherein said semiconductor comprises at least one from the group of silicon and gallium arsenide.

17. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 16, wherein said common cover plate comprises an anti-reflective coating.

18. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 1, further comprising a common cover plate disposed adjacent and substantially parallel to said microdisplays.

19. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 18, wherein said common cover plate comprises at least one electrically conductive layer.

20. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 19, further comprising a plurality of spacers for offsetting said common cover plate relative to said substrate for providing a predetermined space therebetween.

21. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 20, further comprising sealing means disposed between said common cover plate and said substrate.

22. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 21, further comprising liquid crystal material disposed in said predetermined space.

23. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 1, wherein for special color, each of said pixel-active areas comprises a primary color element.

24. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 1, further comprising at least one polarizing layer.

25. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 1, further comprising a passivation layer disposed adjacent said at least one image formation plane.

26. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 1, further comprising a liquid crystal aligning layer proximate said liquid crystal material for orienting the liquid crystal molecules thereof.

27. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 26, further comprising a passivation layer disposed adjacent said at least one image formation plane.

28. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 1, wherein at least one of said plurality of microdisplays comprises a reflective liquid crystal microdisplay.

29. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 1, wherein at least one of said plurality of microdisplays comprises a vacuum field emissive microdisplay.

30. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 1, wherein at least one of said plurality of microdisplays comprises a light emissive microdisplay.

31. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 1, wherein at least one of said plurality of microdisplays comprises a micromirror display.

32. A tiled, substantially flat, panel display comprising a plurality of microdisplay tiles, each of said microdisplays being capable of displaying no less than a 640×

480 array of pixels at a pixel pitch no greater that approximately 30 μ

m and occupying a space no greater than about 45×

55 mm, said display having the characteristic of a visually imperceptible seam, such that said panel display can be viewed as though it were a single, monolithic display, comprising;

a) means defining an image viewing plane;

b) a plurality of microdisplay tiles each having a reflective image formation plane upon which is formed at least a segment of an image, said segment of an image being combinable into a complete image at said image viewing plane, said microdisplay tiles being disposed in a plane substantially parallel to said image formation plane;

c) means for enlarging and protecting said image segments into said viewing plane, thereby forming said complete image having no visually perceptible discontinuities between said enlarged image segments;

d) means defining a seam disposed between adjacently disposed microdisplay tiles; and

e) masking means disposed proximate said seam for blocking light directed from said seam towards a viewer of said display, thereby making said seam substantially visually imperceptible to said viewer.

33. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 32, further comprising light-transferring means disposed adjacent said image formation plane.

34. The tiled, substantially flat, panel display composed of a plurality of microdisplays in accordance with claim 33, further comprising a plurality of focusing devices for coupling light into said image formation plane.