U.S. patent application number 09/847447 was filed with the patent office on 2002-11-07 for large format emissive display.
Invention is credited to Kwasnick, Robert F., Morley, Roland M., Sundahl, Robert C..
Application Number | 20020163301 09/847447 |
Document ID | / |
Family ID | 25300643 |
Filed Date | 2002-11-07 |
United States Patent
Application |
20020163301 |
Kind Code |
A1 |
Morley, Roland M. ; et
al. |
November 7, 2002 |
Large format emissive display
Abstract
A backframe may be utilized to align a plurality of emissive
display tiles precisely with respect to one another. The individual
display tiles may be removable from the backframe for replacement
or other reasons. As a result, the spacing between individual tiles
in an overall large format display may be precisely controlled in
some cases. In addition, regularly occurring gaps between adjacent
tiles may be filled with a suitable light absorbing material to
reduce the visibility of seams.
Inventors: |
Morley, Roland M.; (Tempe,
AZ) ; Kwasnick, Robert F.; (Palo Alto, CA) ;
Sundahl, Robert C.; (Phoenix, AZ) |
Correspondence
Address: |
Timothy N. Trop
TROP, PRUNER & HU, P.C.
8554 KATY FWY, STE 100
HOUSTON
TX
77024-1805
US
|
Family ID: |
25300643 |
Appl. No.: |
09/847447 |
Filed: |
May 2, 2001 |
Current U.S.
Class: |
313/506 |
Current CPC
Class: |
G02F 1/13336
20130101 |
Class at
Publication: |
313/506 |
International
Class: |
H05B 033/08 |
Claims
What is claimed is:
1. A large format display comprising: a plurality of emissive
display modules, each module including at least two alignment
elements; and a backframe including a plurality of alignment
devices to mate with the alignment elements of said display
modules.
2. The display of claim 1 wherein each module includes an
electroluminescent display tile secured to a backplate, said
backplate including said alignment elements.
3. The display of claim 2, said display tile including front and
back surfaces and including a driver chip on the back surface of
said display tile and one more emissive elements on the front
surface thereof.
4. The display of claim 3, said modules including fasteners
extending from said backplates.
5. The display of claim 4 including elements on said backframe that
engage said fasteners to secure said backframe to said modules.
6. The display of claim 4 wherein said backframe removeably
connects said modules to said backframe.
7. The display of claim 6 wherein said fasteners are threaded
fasteners.
8. The display of claim 1 wherein each module includes a
transparent layer and a plurality of spaced apart light emissive
cells formed on said layer and defining regions between said
cells.
9. The display of claim 8 including an optically absorbing material
formed on said layer so as to overlay the region between the
cells.
10. The display of claim 1 including a plurality of gaps between
adjacent modules, said gaps being covered by an optically absorbing
material.
11. The display of claim 10 including an optically clear adhesive
between adjacent modules.
12. A method comprising: engaging a plurality of emissive display
modules with a backframe; and aligning said modules with respect
one another using a characteristic of said backframe.
13. The method of claim 12 wherein aligning includes causing pins
on one of said modules or said backframe to engage holes in one of
said modules or said backframe.
14. The method of claim 12 including forming said modules by
securing light emitting tiles to a backplate having alignment
elements, and causing said alignment elements to engage alignment
devices on said backframe.
15. The method of claim 14 including providing tiles with a
plurality of light emitting cells, and coating a region visually
between the cells with optically absorbent material.
16. The method of claim 14 including filling the seams between
adjacent modules with an optical adhesive.
17. The method of claim 14 including threadedly securing said
modules to said backframe.
18. The method of claim 17 including filling the seams between
adjacent modules with an optical adhesive material and covering the
adhesive material with an optically absorbing material.
19. A system to connect tiles together to form a large format
display, said system comprising: a backplate to mount a tile, said
backplate including at least two alignment pins; and a backframe
including a plurality of alignment holes to receive the pins of
said backplate.
20. The system of claim 19 wherein said backplate includes
fasteners extending outwardly from a surface thereof.
21. The system of claim 20 wherein a threaded fastener is utilized
to secure said backplate to said backframe.
22. A method comprising: forming a display device having a
plurality of spaced, light emitting cells; and coating the device
with a matrix of light absorbing material.
23. The method of claim 22 including forming said spaced light
emitting cells on one side of a transparent layer.
24. The method of claim 23 including coating a second side of said
transparent layer with said absorbing material.
25. The method of claim 24 including coating said transparent layer
at locations overlying the regions between spaced, light emitting
cells with first stripes of black material of a first width,
coating the regions between the edge displays of the devices and
the light emitting cells with a black second stripe of a smaller
width, and joining display devices together so that said second
stripes have a combined width approximately equal to the width of
said first stripes.
26. A method of forming a large format display comprising: securing
a plurality of light emissive display tiles to one another;
defining gaps between adjacent display tiles; and filing said gaps
with a light absorbing material.
27. The method of claim 26 including adhesively coupling said
display tiles to one another by injecting adhesive into said gaps
and covering said adhesive with a light absorbing material.
28. The method of claim 27 including using display tiles having a
plurality of light emitting cells and coating the regions between
said cells with a light absorbing material.
29. The method of claim 26 including securing said tiles to a
support and defining structure on said tiles and said support to
align said tiles.
30. The method of claim 29 including removeably mounting said tiles
on said support.
Description
BACKGROUND
[0001] This invention relates generally to large format emissive
displays.
[0002] Large format displays may be utilized to create displays of
a size greater than the size of conventional displays. For example,
large format displays may combine the images produced from a
plurality of conventional displays. The composite display may be
able to produce an image which is much larger and more economical
than that possible with existing display technologies.
[0003] Emissive displays include light emitting diodes, liquid
crystal displays, and organic light emitting displays. These
displays actually emit light at the pixel level which can perceived
by viewers. Emissive displays may be combined together to create a
large format display.
[0004] When emissive displays are combined to create a large format
display, those displays may suffer from visible seams. The visible
seams arise from the joints between the combined displays. The user
looking at the large format display notices the individual displays
which together are combined to create the overall image. Thus in
some cases, the large format display may not produce a seamless
image.
[0005] Another problem with large format displays is that the
individual displays that are combined to form the large format
display may be misaligned with respect to one another. Even the
slightest misalignment may result in an irregularity in the overall
image that may be noticeable to anyone viewing the large format
display.
[0006] Thus, there is a need for better ways to combine emissive
displays into large format displays.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a perspective view of an emissive display tile in
accordance with one embodiment of the present invention;
[0008] FIG. 2 is a side elevational view of an emissive display
module in accordance with one embodiment of the present invention;
and
[0009] FIG. 3 is a front elevational view of a large format display
in accordance with one embodiment of the present invention.
DETAILED DESCRIPTION
[0010] Referring to FIG. 1, an emissive display tile 100 may
include a plurality of electroluminescent cells 20 each producing a
pixel or subpixel of monochrome or color light. Thus, the cells 20
in a given display tile 100 may produce one or more pixels or
subpixels of light which can contribute to the display of an image.
In some cases, a large number of cells 20 may be utilized. In
another case, fewer cells may be appropriate.
[0011] The display tile 100 may include an integrated circuit
driver chip 10. The chip 10, mounted on the lower surface of the
display tile 100, actually drives the display cells 20 by way of
electrical connections in feedthroughs (not shown).
[0012] The tile 100 may include a body 24. In one embodiment, the
body 24 may be a ceramic layer. Over the body 24 is a transparent
layer 104 which may be formed of glass. A black material 102 is
applied in a grid pattern on the top surface of the transparent
layer 104.
[0013] The emissive cells 20 may actually be formed on the bottom
surface of the transparent layer 104. The cells 20 are then visible
from above, as shown in FIG. 1, because of the transparent nature
of the transparent layer 104. In one embodiment, each cell 20 may
include three light emitting elements such as a red, green and blue
light emitting element.
[0014] The black material 102 includes an intermediate section 102a
of greater width and a peripheral section 102b that may be less
than one-half the width of the material 102a. Thus, when tiles 100
are butted one against the other and a slight gap is left between
adjacent tiles, the combined sections 102b from two adjacent tiles
100 have a resulting width approximately equal to that of the
section 102a. As a result, when the combined display is viewed, it
has a consistent matrix pattern of pixels.
[0015] The black material 102 forms a matrix that covers the voids
between individual cells 20. This may reduce reflection from
electrode structures (not shown) on the bottom surface of the
transparent layer 104 thereby increasing pixel contrast. The matrix
102 may be a grid of optically black absorbing material that covers
the horizontal and vertical spaces between the cells 20 in the form
of horizontal and vertical stripes. In one embodiment black
material 102a may have a width that is a fraction, usually between
0.25 and 0.5 of the pixel-to-pixel spacing, to allow for
misalignment between tiles when formed onto an array of tiles.
Patterning may be achieved by transfer screen printing, ink jet
printing or other methods capable of producing spatial positioning
tolerances and feature sizes on the order of 10 microns.
[0016] The black matrix material 102 may be optically absorbing to
visible wavelengths of light and resistant to removal during
cleaning of the completed assembly with water or mild solvents. As
one example, a black emulsion, as typically used in photomask
fabrication may be used for this purpose.
[0017] Referring to FIG. 2, the tile 100 may be mounted on a
backplate 110. Each module 101, composed of a tile 100 with a
backplate 110, may be optically, electrically and mechanically
interchangeable with a plurality of other components in accordance
with one embodiment of the present invention. The module assembly
is performed at an optical alignment station that provides x,y and
z dimensions to tolerances of about 10 microns in each direction.
This means that the smallest pixel pitch for a seamless appearance
is about one millimeter.
[0018] The backplate 110 may provide mechanical support to the
display tile 100. The backplate 110 may assembled to the display
tile 100 using a thin, flexible epoxy adhesive in one
embodiment.
[0019] A pair of alignment elements 112 on the backplate 110
provide x and y alignment control at display assembly between the
display tile 100 and the backplate 110. A variety of alignment
elements 112 may be used including holes, grooves, tabs, and a
variety of pin shapes as a few examples. An exemplary backplate 110
thickness may be one millimeter or more.
[0020] The backplate 110 may be smaller in size than the tile 100
by about one millimeter or more in one embodiment. Cut out regions
(not shown) in the backplate 110 may provide clearance for tile
electronics such as the chip 10 and connectors that are disposed on
the back side of the tile 100. The backplate 110 may also include
fastener extensions 114 for attachment to a backframe (not shown in
FIG. 2).
[0021] Referring to FIG. 3, the backframe 120 may include a number
of alignment devices 124 to receive the alignment elements 112 and
fasteners 114 of a plurality of modules 101. The alignment devices
124 may be pins, holes, grooves, or tabs, as a few examples. The
alignment devices 124 mate with and align the alignment elements
112. As a result, a large number of modules 101 may be secured on
the backframe 120 in precise relative alignment. The fasteners 114
may be secured onto the backframe 120 using nuts 122 as one
example. However, any of a variety of other fasteners may be
utilized as well, including rivets, releasable catches, friction
welds, and solder, as additional examples.
[0022] The seams between adjacent modules 101 can then be filled by
an optically clear, substantially index matching gap material 128.
The gap material 128 may be an adhesive such as an acrylic or
silicone adhesive. The gap material 128, for example, may be
dispensed by syringe from the front side of the large format
display 200. The gap material 128 may reduce the amount light
scattered from the edges of each panel which would otherwise cause
a seam to be visible, particularly when viewed off-axis.
[0023] To aid in the replacement of the individual display modules
101, a reworkable adhesive may be utilized as the gap material 128
in one embodiment. For example, an ultraviolet degradable epoxy may
be used.
[0024] A black patterned coating 126 may be applied to the front of
the large format display 200 in a form of horizontal and vertical
stripes to cover the front of the seams, for example using a
syringe. The width of the coating 126 may substantially match the
width of the stripes of material 102a patterned on the individual
tiles 100. The material used in the coating 126 may be identical to
or similar in optical and mechanical properties to the material 102
used to pattern the stripes on the individual tiles 100.
[0025] The patterning results in a visual effect that presents a
low contrast mesh pattern superimposed over the displayed image.
This pattern may become part of the pixelated structure of the
display, at a spatial frequency equal to that of the pixels. For
normal viewing the distances between the fine structure of this
pattern may not be resolvable in some embodiments. If one tile 100
must be replaced, its module 101 may be readily disconnected from
the backframe 120.
[0026] While the present invention has been described with respect
to a limited number of embodiments, those skilled in the art will
appreciate numerous modifications and variations therefrom. It is
intended that the appended claims cover all such modifications and
variations as fall within the true spirit and scope of this present
invention.
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