U.S. patent application number 16/826633 was filed with the patent office on 2020-07-23 for electro-optic display apparatus.
The applicant listed for this patent is E Ink Corporation. Invention is credited to George G. HARRIS, Richard J. PAOLINI, JR..
Application Number | 20200233250 16/826633 |
Document ID | / |
Family ID | 60572602 |
Filed Date | 2020-07-23 |
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United States Patent
Application |
20200233250 |
Kind Code |
A1 |
HARRIS; George G. ; et
al. |
July 23, 2020 |
Electro-Optic Display Apparatus
Abstract
A display apparatus including: a plurality of display tiles; a
controller configured to control the display tiles; a mounting
structure for mounting the plurality of display tiles, the mounting
structure including a conductive interconnect layer having a
plurality of traces configured to connected the plurality of
display tiles to the controller, and a connector connecting at
least one display tile to the mounting structure. The at least one
display tile is sufficiently flexible to have a curvature, wherein
the curvature produces a space between the at least one display
tile and the mounting structure to house the controller.
Inventors: |
HARRIS; George G.; (Woburn,
MA) ; PAOLINI, JR.; Richard J.; (Framingham,
MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
E Ink Corporation |
Billerica |
MA |
US |
|
|
Family ID: |
60572602 |
Appl. No.: |
16/826633 |
Filed: |
March 23, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15618691 |
Jun 9, 2017 |
|
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16826633 |
|
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62348801 |
Jun 10, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02F 1/1681 20190101;
G02F 1/16753 20190101; G02F 1/16755 20190101; G02F 1/133305
20130101; G02F 1/13336 20130101; G02F 1/167 20130101; G02F 1/1676
20190101 |
International
Class: |
G02F 1/1333 20060101
G02F001/1333; G02F 1/167 20060101 G02F001/167 |
Claims
1. A method for producing a display apparatus having a plurality of
flexible display tiles controlled by a controller, the method
comprising: providing a mounting structure with predetermined
positions for mounting the plurality of display tiles; producing a
conductive interconnect layer having a plurality of traces
configured to connected the plurality of display tiles to the
controller; mounting at least one display tile to the mounting
structure, the at least one display tile being sufficiently
flexible to have a curvature such that the curvature produces a
space between the at least one display tile and the mounting
structure; and placing the controller in the space between the at
least one display tile and the mounting structure.
2. The method of claim 1 further comprising providing an insulator
layer to insulate the interconnect layer from the at least one
display tile.
3. The method of claim 1, wherein the producing the conductive
interconnect layer step further comprises etching the interconnect
layer to produce conductive traces.
4. The method of claim 1, wherein the mounting step further
comprises connecting the mounting structure and the at least one
display tile using a connector.
5. The method of claim 1, wherein the producing the conductive
interconnect layer step further comprises using a laser to produce
conductive traces.
6. The method of claim 1, wherein the space housing the controller
is located between the reverse side of the display tile and the
mounting structure.
7. A display apparatus comprising: a plurality of display tiles; a
controller configured to control the display tiles; a mounting
structure for mounting the plurality of display tiles, the mounting
structure comprising a conductive interconnect layer having a
plurality of traces configured to connected the plurality of
display tiles to the controller; and a connector connecting at
least one display tile to the mounting structure; wherein: the at
least one display tile is sufficiently flexible to have a
curvature, wherein the curvature produces a space between the at
least one display tile and the mounting structure to house the
controller.
8. The display apparatus of claim 7 wherein the connector connects
the at least one display tile to the conductive interconnect
layer.
9. The display apparatus of claim 7 wherein the mounting structure
is flexible.
10. The display apparatus of claim 7, wherein the mounting
structure further comprises an insulator layer positioned between
the display tiles and the conductor layer.
11. The display apparatus of claim 7, wherein the at least one
display tile comprises a flexible front electrode.
14. The display apparatus of claim 7, wherein the at least one
display tile comprises a reverse side conductor layer.
15. The display apparatus of claim 14, wherein the connector
connects the reverse side conductor layer to the conductive
interconnect layer.
16. The display apparatus of claim 7, wherein the at least one
display tile comprises, in order: a front electrode; a layer of
electrophoretic display material; a pixel conductor layer; a
substrate layer; and a reverse side conductor layer.
17. The display apparatus of claim 16, wherein the connector
connects the reverse side conductor layer to the conductive
interconnect layer.
18. The display apparatus of claim 7, wherein the space housing the
controller is located between the reverse side of the at least one
tile and the mounting structure.
19. The display apparatus of claim 7, wherein the at least one
display tile comprises a plurality of pixels.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. patent application
Ser. No. 15/618,691 filed on Jun. 9, 2017 and claiming priority to
U.S. Provisional Application 62/348,801 filed on Jun. 10, 2016. The
entire content of the above mentioned application is herein
incorporated by reference.
SUBJECT OF THE INVENTION
[0002] This invention relates to electro-optic display apparatus.
More specifically, this invention provides means for assembling
multiple electro-optic displays into a larger display apparatus in
a convenient fashion.
BACKGROUND OF INVENTION
[0003] For some display applications it may be desirable to
assemble a plurality of electro-optic together to form a larger
display screen. To connect the plurality of displays, normally a
set of connecting cables are required for connecting each display
to an electrical driver unit. Furthermore, one or more alignment
frame structures will be required to properly position the
displays. The overall assembly of the displays typically will
require careful measurements and precise placements of the
individual displays. In operation, the connecting cables are either
highly customized for individual display apparatus designs, and in
addition, customized connection cables can be time-consuming to
assemble and be error prone when installing, making this approach
suitably only for low volume applications and prototypes.
Alternatively, the display connections can include modular
subcomponents that are inter-connectable to span the distance
between each display and the driver unit. In this fashion, such
approach is feasible only for large volume applications where
production cost may be averaged down by a large number of displays
apparatus produced.
[0004] The subject matter presented herein provides means to
assemble a plurality of displays into display apparatus of various
configurations conveniently and at a low cost.
SUMMARY OF INVENTION
[0005] In a first aspect, the present application provides a method
for producing a display apparatus having a plurality of display
tiles controlled by a controller, the method including: providing a
mounting structure with predetermined positions for mounting the
plurality of display tiles; producing a conductive interconnect
layer having a plurality of traces configured to connected the
plurality of display tiles to the controller; mounting at least one
display tile to the mounting structure, the at least one display
tile being sufficiently flexible to have a curvature such that the
curvature produces a space between the at least one display tile
and the mounting structure; and placing the controller in the space
between the at least one display tile and the mounting
structure.
[0006] In a second aspect, the present application provides a
mounting structure for mounting a plurality of display tiles
controlled by a controller, the structure comprising: an insulator
layer with through holes matching the placements of the plurality
of display tiles; and a conductive interconnect layer configured to
connect the plurality of display tiles to the controller, the
conductive interconnect layer having plurality of traces extending
from the controller to the through holes on the insulator
layer.
[0007] In a third aspect, the present application provides a
display apparatus including: a plurality of display tiles; a
controller configured to control the display tiles; a mounting
structure for mounting the plurality of display tiles, the mounting
structure including a conductive interconnect layer having a
plurality of traces configured to connected the plurality of
display tiles to the controller, and a connector connecting at
least one display tile to the mounting structure. The at least one
display tile is sufficiently flexible to have a curvature, wherein
the curvature produces a space between the at least one display
tile and the mounting structure to house the controller.
BRIEF DESCRIPTION OF DRAWINGS
[0008] FIG. 1 illustrates an electrophoretic image display in
accordance with the subject matter presented herein;
[0009] FIG. 2 illustrates an exemplary mounting structure for
assembling a plurality of displays in accordance with the subject
matter presented herein;
[0010] FIG. 3 illustrates a set of conductive interconnects in
accordance with the subject matter presented herein; and
[0011] FIG. 4 illustrates a printed graphics layer in accordance
with the subject matter presented herein.
[0012] FIG. 5 illustrates an exemplary pixel conductor layer for a
display tile with a plurality of irregularly shaped pixel driving
electrodes in accordance with the subject matter presented
herein;
[0013] FIG. 6 illustrates an exemplary substrate for a display tile
in accordance with the subject matter presented herein;
[0014] FIG. 7 illustrates a reverse side conductor layer with
conductive traces in accordance with the subject matter presented
herein.
[0015] FIGS. 8A and 8B illustrate flexible display tiles with
various curvatures; and
[0016] FIG. 9 illustrates a flexible display tile mounted onto a
mounting structure.
DETAILED DESCRIPTION
[0017] The subject matter presented herein relates to an apparatus
for assemble a plurality of electro-optic displays. Such apparatus
may include a conductive interconnect layer having a set of printed
conductive interconnects for connecting the plurality of displays,
and a printed graphics overlay layer for aligning the displays. The
electro-optic displays of the present subject matter are
especially, but not exclusively, intended for use with
particle-based electrophoretic displays in which one or more types
of electrically charged particles are suspended in a liquid and are
moved through the liquid under the influence of an electric field
to change the appearance of the display.
[0018] The term "electro-optic" as applied to a material or a
display, is used herein in its conventional meaning in the imaging
art to refer to a material having first and second display states
differing in at least one optical property, the material being
changed from its first to its second display state by application
of an electric field to the material. Although the optical property
is typically color perceptible to the human eye, it may be another
optical property, such as optical transmission, reflectance,
luminescence or, in the case of displays intended for machine
reading, pseudo-color in the sense of a change in reflectance of
electromagnetic wavelengths outside the visible range.
[0019] The term "gray state" is used herein in its conventional
meaning in the imaging art to refer to a state intermediate two
extreme optical states of a pixel, and does not necessarily imply a
black-white transition between these two extreme states. For
example, several of the E Ink patents and published applications
referred to below describe electrophoretic displays in which the
extreme states are white and deep blue, so that an intermediate
"gray state" would actually be pale blue. Indeed, as already
mentioned, the change in optical state may not be a color change at
all. The terms "black" and "white" may be used hereinafter to refer
to the two extreme optical states of a display, and should be
understood as normally including extreme optical states which are
not strictly black and white, for example, the aforementioned white
and dark blue states. The term "monochrome" may be used hereinafter
to denote a drive scheme which only drives pixels to their two
extreme optical states with no intervening gray states.
[0020] Some electro-optic materials are solid in the sense that the
materials have solid external surfaces, although the materials may,
and often do, have internal liquid- or gas-filled spaces. Such
displays using solid electro-optic materials may hereinafter for
convenience be referred to as "solid electro-optic displays". Thus,
the term "solid electro-optic displays" includes rotating bichromal
member displays, encapsulated electrophoretic displays, microcell
electrophoretic displays and encapsulated liquid crystal
displays.
[0021] The terms "bistable" and "bistability" are used herein in
their conventional meaning in the art to refer to displays
comprising display elements having first and second display states
differing in at least one optical property, and such that after any
given element has been driven, by means of an addressing pulse of
finite duration, to assume either its first or second display
state, after the addressing pulse has terminated, that state will
persist for at least several times, for example at least four
times, the minimum duration of the addressing pulse required to
change the state of the display element. It is shown in published
US Patent Application No. 2002/0180687 (see also the corresponding
International Application Publication No. WO 02/079869) that some
particle-based electrophoretic displays capable of gray scale are
stable not only in their extreme black and white states but also in
their intermediate gray states, and the same is true of some other
types of electro-optic displays. This type of display is properly
called "multi-stable" rather than bistable, although for
convenience the term "bistable" may be used herein to cover both
bistable and multi-stable displays.
[0022] Several types of electro-optic displays are known. One type
of electro-optic display is a rotating bichromal member type as
described, for example, in U.S. Pat. Nos. 5,808,783; 5,777,782;
5,760,761; 6,054,071 6,055,091; 6,097,531; 6,128,124; 6,137,467;
and 6,147,791 (although this type of display is often referred to
as a "rotating bichromal ball" display, the term "rotating
bichromal member" is preferred as more accurate since in some of
the patents mentioned above the rotating members are not
spherical). Such a display uses a large number of small bodies
(typically spherical or cylindrical) which have two or more
sections with differing optical characteristics and an internal
dipole. These bodies are suspended within liquid-filled vacuoles
within a matrix, the vacuoles being filled with liquid so that the
bodies are free to rotate. The appearance of the display is changed
by applying an electric field thereto, thus rotating the bodies to
various positions and varying which of the sections of the bodies
is seen through a viewing surface. This type of electro-optic
medium is typically bistable.
[0023] Another type of electro-optic display uses an electrochromic
medium, for example, an electrochromic medium in the form of a
nanochromic film comprising an electrode formed at least in part
from a semi-conducting metal oxide and a plurality of dye molecules
capable of reversible color change attached to the electrode; see,
for example O'Regan, B., et al., Nature 1991, 353, 737; and Wood,
D., Information Display, 18(3), 24 (March 2002). See also Bach, U.,
et al., Adv. Mater., 2002, 14(11), 845. Nanochromic films of this
type are also described, for example, in U.S. Pat. Nos. 6,301,038;
6,870,657; and 6,950,220. This type of medium is also typically
bistable.
[0024] Another type of electro-optic display is an electro-wetting
display developed by Philips and described in Hayes, R. A., et al.,
"Video-Speed Electronic Paper Based on Electrowetting", Nature,
425, 383-385 (2003). It is shown in U.S. Pat. No. 7,420,549 that
such electro-wetting displays can be made bistable.
[0025] One type of electro-optic display, which has been the
subject of intense research and development for a number of years,
is the particle-based electrophoretic display, in which a plurality
of charged particles move through a fluid under the influence of an
electric field. Electrophoretic displays can have attributes of
good brightness and contrast, wide viewing angles, state
bistability, and low power consumption when compared with liquid
crystal displays. Nevertheless, problems with the long-term image
quality of these displays have prevented their widespread usage.
For example, particles that make up electrophoretic displays tend
to settle, resulting in inadequate service-life for these
displays.
[0026] As noted above, electrophoretic media require the presence
of a fluid. In most prior art electrophoretic media, this fluid is
a liquid, but electrophoretic media can be produced using gaseous
fluids; see, for example, Kitamura, T., et al., "Electrical toner
movement for electronic paper-like display", IDW Japan, 2001, Paper
HCS1-1, and Yamaguchi, Y., et al., "Toner display using insulative
particles charged triboelectrically", IDW Japan, 2001, Paper
AMD4-4). See also U.S. Pat. Nos. 7,321,459 and 7,236,291. Such
gas-based electrophoretic media appear to be susceptible to the
same types of problems due to particle settling as liquid-based
electrophoretic media, when the media are used in an orientation
which permits such settling, for example in a sign where the medium
is disposed in a vertical plane. Indeed, particle settling appears
to be a more serious problem in gas-based electrophoretic media
than in liquid-based ones, since the lower viscosity of gaseous
suspending fluids as compared with liquid ones allows more rapid
settling of the electrophoretic particles.
[0027] Numerous patents and applications assigned to or in the
names of the Massachusetts Institute of Technology (MIT) and E Ink
Corporation have recently been published describing encapsulated
electrophoretic media. Such encapsulated media comprise numerous
small capsules, each of which itself comprises an internal phase
containing electrophoretically-mobile particles suspended in a
liquid suspension medium, and a capsule wall surrounding the
internal phase. Typically, the capsules are themselves held within
a polymeric binder to form a coherent layer positioned between two
electrodes. The technologies described in these patents and
applications include: [0028] (a) Electrophoretic particles, fluids
and fluid additives; see for example U.S. Pat. Nos. 7,002,728 and
7,679,814; [0029] (b) Capsules, binders and encapsulation
processes; see for example U.S. Pat. Nos. 6,922,276 and 7,411,719;
[0030] (c) Microcell structures, wall materials, and methods of
forming microcells; see for example U.S. Pat. Nos. 7,072,095 and
9,279,906; [0031] (d) Methods for filling and sealing microcells;
see for example U.S. Pat. Nos. 7,144,942 and 7,715,088; [0032] (e)
Films and sub-assemblies containing electro-optic materials; see
for example U.S. Pat. Nos. 6,982,178 and 7,839,564; [0033] (f)
Backplanes, adhesive layers and other auxiliary layers and methods
used in displays; see for example U.S. Pat. Nos. D485,294;
6,124,851; 6,130,773; 6,177,921; 6,232,950; 6,252,564; 6,312,304;
6,312,971; 6,376,828; 6,392,786; 6,413,790; 6,422,687; 6,445,374;
6,480,182; 6,498,114; 6,506,438; 6,518,949; 6,521,489; 6,535,197;
6,545,291; 6,639,578; 6,657,772; 6,664,944; 6,680,725; 6,683,333;
6,724,519; 6,750,473; 6,816,147; 6,819,471; 6,825,068; 6,831,769;
6,842,167; 6,842,279; 6,842,657; 6,865,010; 6,873,452; 6,909,532;
6,967,640; 6,980,196; 7,012,735; 7,030,412; 7,075,703; 7,106,296;
7,110,163; 7,116,318; 7,148,128; 7,167,155; 7,173,752; 7,176,880;
7,190,008; 7,206,119; 7,223,672; 7,230,751; 7,256,766; 7,259,744;
7,280,094; 7,301,693; 7,304,780; 7,327,511; 7,347,957; 7,349,148;
7,352,353; 7,365,394; 7,365,733; 7,382,363; 7,388,572; 7,401,758;
7,442,587; 7,492,497; 7,535,624; 7,551,346; 7,554,712; 7,583,427;
7,598,173; 7,605,799; 7,636,191; 7,649,674; 7,667,886; 7,672,040;
7,688,497; 7,733,335; 7,785,988; 7,830,592; 7,843,626; 7,859,637;
7,880,958; 7,893,435; 7,898,717; 7,905,977; 7,957,053; 7,986,450;
8,009,344; 8,027,081; 8,049,947; 8,072,675; 8,077,141; 8,089,453;
8,120,836; 8,159,636; 8,208,193; 8,237,892; 8,238,021; 8,362,488;
8,373,211; 8,389,381; 8,395,836; 8,437,069; 8,441,414; 8,456,589;
8,498,042; 8,514,168; 8,547,628; 8,576,162; 8,610,988; 8,714,780;
8,728,266; 8,743,077; 8,754,859; 8,797,258; 8,797,633; 8,797,636;
8,830,560; 8,891,155; 8,969,886; 9,147,364; 9,025,234; 9,025,238;
9,030,374; 9,140,952; 9,152,003; 9,152,004; 9,201,279; 9,223,164;
9,285,648; and 9,310,661; and U.S. Patent Applications Publication
Nos. 2002/0060321; 2004/0008179; 2004/0085619; 2004/0105036;
2004/0112525; 2005/0122306; 2005/0122563; 2006/0215106;
2006/0255322; 2007/0052757; 2007/0097489; 2007/0109219;
2008/0061300; 2008/0149271; 2009/0122389; 2009/0315044;
2010/0177396; 2011/0140744; 2011/0187683; 2011/0187689;
2011/0292319; 2013/0250397; 2013/0278900; 2014/0078024;
2014/0139501; 2014/0192000; 2014/0210701; 2014/0300837;
2014/0368753; 2014/0376164; 2015/0171112; 2015/0205178;
2015/0226986; 2015/0227018; 2015/0228666; 2015/0261057;
2015/0356927; 2015/0378235; 2016/077375; 2016/0103380; and
2016/0187759; and International Application Publication No. WO
00/38000; European Patents Nos. 1,099,207 B1 and 1,145,072 B1;
[0034] (g) Color formation and color adjustment; see for example
U.S. Pat. Nos. 7,075,502 and 7,839,564; [0035] (h) Methods for
driving displays; see for example U.S. Pat. Nos. 7,012,600 and
7,453,445; [0036] (i) Applications of displays; see for example
U.S. Pat. Nos. 7,312,784 and 8,009,348; and [0037] (j)
Non-electrophoretic displays, as described in U.S. Pat. No.
6,241,921 and U.S. Patent Applications Publication Nos.
2015/0277160, and applications of encapsulation and microcell
technology other than displays; see for example U.S. Patent
Application Publications Nos. 2015/0005720 and 2016/0012710.
[0038] Many of the aforementioned patents and applications
recognize that the walls surrounding the discrete microcapsules in
an encapsulated electrophoretic medium could be replaced by a
continuous phase, thus producing a so-called polymer-dispersed
electrophoretic display, in which the electrophoretic medium
comprises a plurality of discrete droplets of an electrophoretic
fluid and a continuous phase of a polymeric material, and that the
discrete droplets of electrophoretic fluid within such a polymer
dispersed electrophoretic display may be regarded as capsules or
microcapsules even though no discrete capsule membrane is
associated with each individual droplet; see for example, the
aforementioned U.S. Pat. No. 6,866,760. Accordingly, for purposes
of the present application, such polymer-dispersed electrophoretic
media are regarded as subspecies of encapsulated electrophoretic
media.
[0039] A related type of electrophoretic display is a so-called
"microcell electrophoretic display". In a microcell electrophoretic
display, the charged particles and the fluid are not encapsulated
within microcapsules but instead are retained within a plurality of
cavities formed within a carrier medium, typically a polymeric
film. See, for example, U.S. Pat. Nos. 6,672,921 and 6,788,449,
both assigned to Sipix Imaging.
[0040] Although electrophoretic media are often opaque (since, for
example, in many electrophoretic media, the particles substantially
block transmission of visible light through the display) and
operate in a reflective mode, many electrophoretic displays can be
made to operate in a so-called "shutter mode" in which one display
state is substantially opaque and one is light-transmissive. See,
for example, U.S. Pat. Nos. 5,872,552; 6,130,774; 6,144,361;
6,172,798; 6,271,823; 6,225,971; and 6,184,856. Dielectrophoretic
displays, which are similar to electrophoretic displays but rely
upon variations in electric field strength, can operate in a
similar mode; see U.S. Pat. No. 4,418,346. Other types of
electro-optic displays may also be capable of operating in shutter
mode. Electro-optic media operating in shutter mode may be useful
in multi-layer structures for full-color displays; in such
structures, at least one layer adjacent the viewing surface of the
display operates in shutter mode to expose or conceal a second
layer more distant from the viewing surface.
[0041] The subject matters described herein make it possible to
create a display apparatus consisting of a plurality of
electro-optic displays or display tiles. In some embodiments, the
plurality of electro-optic displays or display tiles may be
electrophoretic image displays (EPID). An EPID 100, as illustrated
in FIG. 1, may include a backplane 102 having a backplane pixel
layer 108 having a plurality of pixel driving electrodes, a front
electrode layer 104 and a display layer 106. The display layer 106
may include electrophoretic pigment particles enclosed in
micro-capsules or micro-cups. Illustrated in FIG. 1 are
micro-capsules comprising black and white electrophoretic pigment
particles. The front electrode 104 may represent the viewing side
of the EPID 100, in which case the front electrode 104 may be a
transparent conductor, such as Indium Tin Oxide (ITO) (which in
some cases may be deposited onto a transparent substrate, such as
polyethylene terephthalate (PET)). In the display illustrated in
FIG. 1, the display layer 106 may be a particle-based medium
between layers 104 and 108 that includes a plurality of
micro-capsules 110. Within each capsule 110 is a liquid medium and
one or more types of colored pigment particles that include white
pigment particles 112 and black pigment particles 114. The pigment
particles 112 and/or 114 may be controlled (displaced) with an
electric field (e.g., produced by electrodes on layers 108 and
104), thus making the display 100 operate as an electrophoretic
display when addressed.
[0042] As indicated above, the subject matter presented herein
provides a mounting structure for mounting electro-optic displays
or display tiles. This mounting structure, in some embodiments, may
include a substrate for supporting a conductive interconnect layer.
This substrate may be sufficiently flexible such that it can be
rolled or folded for shipping. In some embodiment, the conductive
interconnect layer may be printed. In some other embodiments, the
conductive interconnect layer may be laser scribed or physically or
mechanically etched, and the substrate will be designed to resist
the piercing cutting of the laser and against etching. In yet some
other embodiments, the conductive interconnect layer may be
produced separately from the mounting substrate and assembled at a
later time. The mounting structure may further include an
additional substrate for printed graphics overlaying the conductive
interconnect layer. This printed graphics substrate may be
fabricated from paper or plastic to function as an electrical
insulator to protect the underneath conductive interconnect
layer.
[0043] In one embodiment, once the dimensions and geometrical
shapes of the displays have been determined, the placements of the
displays and the driver unit can be subsequently determined (e.g.,
drawn onto) on the mounting structure. To connect the displays and
the driver unit, marking traces may be drawn using
computer-aided-design software such as AUTOCAD (Registered Trade
Mark) or Altium. Conductive interconnects can be subsequently
fabricated using the drawn traces as a template. To cover up the
conductive interconnects, a layer of printed graphics may be placed
on top of the conductive interconnects. Holes or vias may be cut
through the layer of printed graphics to allow access to the
conductive interconnects. It should be appreciated that the
conductive interconnects can be fabricated independently, separate
from the other layers, on its own. In this fashion, a designer has
the luxury to freely design and fabricate the conductive
interconnects to any fitting size and configuration. As such, the
designer is not bound by the limitations of any conductive traces
producing equipment but is able to freely fabricate interconnects
any sizes and shapes that are fitting to the designer's
customizations.
[0044] FIG. 2 illustrates a mounting structure 204 where sixteen
electro-optic displays or display tiles 202 may be assembled
together to form a larger display apparatus 200. In one example,
the display tiles 202 can be arranged in a rectangular array (e.g.,
4.times.4) on a mounting structure 204 as shown in FIG. 2, similar
in fashion to how tiles are positioned on a wall, with even spacing
between the tiles. It should be appreciated that the display tiles'
202 rectangular shapes shown here are for illustrative purposes as
the tiles 202 can easily adopt other geometrical shapes.
Furthermore, the subject matter disclosed herein enables the
display tiles 202 to be arranged and assembled in a variety of
configurations. Other than the orderly stacking configuration
illustrated in FIG. 2, the display tiles 202 may be arranged, for
example, with uneven spacing in between, and in an un-orderly
fashion. In some embodiments, the display tiles 202 can be arranged
according to a particular formation to form a pre-determined image.
Or, designers may place display tiles at their discretion to form
specific patterns (e.g., an abstract image etc.).
[0045] In addition, each tile may be given a designated code to
match a particular position on the mounting structure 204. For
example, a display tile (not shown) may be designated 1A to match a
predetermined position 1A on the mounting structure 204, and an end
user may simply match the tile 1A to the predetermined position 1A
when assembling the display apparatus 200.
[0046] In some embodiment, the mounting structure 204 may include a
substrate for supporting a conductive interconnect layer. This
support substrate may be fabricated from a plastic such as
poly(ethylene terephthalate) (PET) and have a thickness of at least
2 mils (51 .mu.m-5 mils (127 .mu.m) or above preferred) and is
sufficiently flexible to be rolled or folded. In some embodiments,
the conductive interconnect layer may be scribed using a beam of
energy or particles (e.g., laser) and the support substrate is
preferably capable of withstanding the cutting of the laser.
Sometimes the conductive interconnects (e.g., traces and/or pads)
connecting the display tiles can be made by drawing traces and/or
pads between the tiles using continuous conductor such as carbon
black or metal-filled ink. Alternatively, interconnecting traces or
pads can be mechanically or laser scribed from a conductive layer
made out of materials such as Indium Tin Oxide (ITO) or sputtered
metal (e.g., aluminum). In yet another embodiment, isolated traces
may be printed using techniques such as screen printing, which may
be suitable for high volume applications where tolling and other
startup expenses may be averaged down.
[0047] Furthermore, the mounting structure can also include another
substrate for printed graphics and this substrate may be placed
over the conductive interconnects layer. This printed graphics
substrate layer can be made from paper or plastic and function both
as an electrical insulator to protect the underlying conductive
interconnects layer and also as a printing surface for the printed
graphics. The printed graphics may be produced using ink jet or
laser jet printing for uniquely customized designs, or gravure
printing for high volume (non-customized) designs. The printed
graphics can function as alignment marks during installation as
well as provide aesthetic appeal to the display apparatus 200.
[0048] To assemble the display apparatus 200, in a preferred
embodiment, a designer can firstly determine the sizes and shapes
of the display tiles 202. The designer can then decide the
placements for each tile and where the conductive interconnects may
be placed on each tile. The placements of the tiles 202 and their
conductive interconnects may be outlined on the same layer as the
printed graphics to simplify installation. Subsequently, the
location of the driver unit for the display apparatus may be
determined. It is preferred that the driver unit is placed behind
one of the display tiles 202. In some embodiments, the display
tiles 202 may be curved outwardly away from the mounting structure
204, leaving spaces behind the tiles for the driver unit.
Alternatively, the driver unit may be placed away from the tiles
202, for example, hidden behind an enclosure (e.g., a baseboard
molding), folded around behind the mounting structure 204 (e.g.,
above a ceiling tile) or at a location that may be conveniently
accessed by display operators.
[0049] Once the placements of the display tiles 202 and the driver
unit have been determined, marking traces may be drawn connecting
the driver unit outputs to the display tiles 202. The marking
traces may be drawn using CAD software such as Autocad, Altium,
PADS or Adobe Illustrator. In some embodiments, fiducial marks may
also be drawn to aid later alignment of the printed graphics to the
conductive interconnects (e.g., traces and/or pads). Subsequently,
the conductive interconnects may be fabricated using the drawn
marking traces as a template. Referring now to FIG. 3, illustrated
is a layer of conductive interconnects 300 for providing electrical
connections to the display tiles. The conductive interconnect layer
300 may be fabricated by printing traces 302 and pads 304 on a
dielectric substrate (e.g., PET) or by scribing a conductive film
(e.g., carbon, silver, aluminum, ITO etc.) already deposited on the
dielectric substrate. Other methods of fabricating the conductive
interconnects 300 may be conveniently adopted here depending on
what manufacturing equipment is available to a user. It should be
noted that the conductive interconnect layer 300 here may be
fabricated separately from all other layers of the display
apparatus 100. In this fashion, a designer is free to utilize any
method to produce the interconnect layer 300 and not be bound by
any interconnect producing equipment. As such, the designer can
fabricate interconnects of any shape or sizes as he sees fitting to
accommodate his designs. This allows the designer freedom to
produce display apparatus of various shapes and configurations and
not be bound by the manufacturing limitations of the conductive
interconnects.
[0050] In use, each display tile may have a connector (e.g., a flat
flex connector) port pre-assembled and a matching connector may be
placed on a pad 304, in this fashion, when assembling a display
apparatus, an user may simply connect the connector on each display
tile to the matching connector on the pads 304, thereby eliminate
the need to produce connecting cables to connect the plurality of
display tiles to the mounting structure, which makes the entire
apparatus more compact and convenient to assemble.
[0051] Referring now to FIG. 4, illustrated is a printed graphics
layer 400 produced on a dielectric substrate which may be later
laminated onto the conductive interconnect layer 300 shown in FIG.
3. On the printed graphics layer 400, placements of the display
tiles and the driver unit have been outlined, together with through
holes 402 for the conductive interconnects. In addition, fiducial
or alignment marks may also be drawn on this layer for aligning
neighboring interconnect mounting structures if multiple structures
or surfaces will be required. Other graphic features such as
artistic designs may be further included for aesthetic purposes.
Once fabricated, through holes or vias may be cut in this layer 400
to allow access to the conductive interconnects where the driver
unit and the display tiles may be connected. The through holes may
be made using laser cutting, a die cutter, scissors etc., depending
on the designer's preference and electrical connections may be made
using conductive pressure sensitive adhesive pads, spring pins, or
electrical connections such as crimped pin/socket pairs (i.e.,
Nicomatic).
[0052] In a preferred embodiment, the printed graphics and the
conductive interconnects may be adhered (e.g., laminated) either
together or separately to the supporting substrate to produce a
single piece of mounting structure or surface. Subsequently, the
display tiles may be positioned onto the mounting structure at
their pre-determined positions. Optionally a mounting frame may
also be provided where the mounting structure and the display tiles
may be attached to the mounting frame.
[0053] Furthermore, the subject matter presented herein also
provides for display tiles to be connected to the mounting
structure 200 presented in FIG. 2. An exemplary display tile may
include a pixel conductor layer, a substrate layer and a reverse
side conductor layer, where the substrate layer may be positioned
between the pixel conductor layer and the reverse side conductor
layer. Driving electrodes for display pixels or pixel segments can
be defined and fabricated on the pixel conductor layer. In a
preferred embodiment, the driving electrodes are firstly patterned
on the pixel conductor layer using a beam of energy or particles
(e.g., laser scribing), where laser scribing allows for the
fabrication of driving electrodes of various sizes and geometric
shapes without using complex machineries. Subsequently, vias can be
created through the substrate layer and conductive traces can be
drawn on the reverse side conductor layer, where the conductive
traces are used for transmitting electrical voltage or driving
waveforms to the driving electrodes through the vias. In this
fashion, the backplane is assembled without having to use
size-limiting techniques such as photolithography or global
alignments, techniques usually required by screen printing or PCB
manufacturing. As such, large sized backplanes with variable sized
driving electrodes can be conveniently and cheaply assembled.
[0054] In some embodiments, specialized display applications will
require a display to use pixel or pixel segments of irregular
geometric shapes. The present subject matter enables the assembly
of a display tile having a plurality of irregular shaped display
pixel segments at a cheap price. FIG. 5 illustrates a pixel
conductor layer 500 for a display tile having a plurality of
irregular shaped pixel segments. As illustrated in FIG. 5, the
pixel conductor layer 500 may include a plurality of variable sized
driving electrodes 511-517 for driving the plurality of irregular
shaped pixel segments (not shown), where the shapes and positions
of the driving electrodes 511-517 will match the shapes and
positions of the corresponding pixel segments. In some embodiments,
the pixel conductor layer 500 may be formed by coating a continuous
layer of conducting material such as ITO onto a substrate. Other
conductive materials may also be sputtered onto a substrate form
the continuous layer, materials such as, but not limited to,
various types of conductive oxides, gold, inert metals, nickel
boron, carbon, carbon nanotubes, graphene, and
poly(3,4-ethylenedioxythiophene) or also known as PEDOT. In some
other embodiments, conductive material such as copper, nickel,
aluminum, silver nanowires and printed silver may also be used
depending on the specific requirements of the display
application.
[0055] According to some embodiments of the present subject matter,
a display tile assembling process may include having a continuous
layer of conductive material scribed by a laser to pattern the
various shaped driving electrodes 511-517. The scribing may cut
deep enough into the conductive material layer to electrically
isolate each driving electrodes but not so deep as to cut through
the underneath substrate or substantially weaken the substrate to
make it fragile. Laser scribing allows for the patterning of
driving electrodes of various geometrical configurations without
having to perform photolithography or global alignments, which can
be prohibitively expensive for large sized displays. FIG. 5 further
illustrates star shaped 520 and circular 522 driving electrodes,
but it should be appreciated that other geometrical shapes can be
easily patterned using laser scribing or other comparable etching
methods commonly adopted in the industry.
[0056] Once the driving electrodes have been patterned, vias can be
created through the substrate to connect the driving electrodes to
driver circuits (not shown). FIG. 6 illustrates an exemplary
substrate layer 600 in accordance with the subject matter presented
herein. In some embodiments, the substrate layer 600 may be
manufactured using materials such as PET, Polyethylene naphthalate
(PEN), cyclic olefins, paper, fabrics, polyimide, or polycarbonate.
To provide electrical connections to the driving electrodes 511-517
as shown in FIG. 5, one or more vias 621-627 may be created through
the substrate layer 600 for each of the driving electrodes 511-517.
Vias 621-627 may be created by cutting through the substrate layer
600 using lasers, but it should be appreciated that mechanical
drilling or other puncturing methods commonly used in the art can
be easily adopted. In some embodiments, a via cut into a driving
electrode may be at least 200 .mu.m in diameter and usually no more
than 3 mm to minimize the appearance of the hole in the final
display. It should appreciated that in other embodiments, vias may
be formed before the driving electrodes have been patterned, for
example, a substrate may come pre-fabricated with vias in place
configured to backplane assembling.
[0057] Once the vias 621-627 have been created, conductive material
(not shown) may be dispensed into the vias 621-627 with a porous
paper behind the substrate and with vacuum pulling on the porous
paper. The vacuum force will pull the conductive material through
the vias 621-627 and plates the sides of the vias 621-627 or fill
the volume of the vias 621-627, connecting the driving electrodes
511-517 to the reverse side of the substrate 600. It is preferred
that the finished vias have surfaces co-planar with both the pixel
conductor layer and the reverse side conductor layer to avoid bumps
resulting from too much filler or lamination void due to
insufficient via filling. In some embodiments, the vias 621-627 may
be filled with a hot melt adhesive with a melting temperature
around the lamination temperature of the electrophoretic ink
material (e.g., 250 F), provided that the flow viscosity of the hot
melt adhesive is low enough to prevent ink capsule rupture.
[0058] The properly filled vias 621-627 can provide electrical
connections between the driving electrodes 511-517 and the
conductive traces that are to be formed on the reverse side (i.e.,
the side opposite to the pixel conductor layer) of the substrate
600. Prior to the formation of the conductive traces, in some
embodiments, an ink FPL stack (not shown) may be firstly laminated
to the driving electrodes 511-517. This is done in this fashion
such that the thickness of the traces would not press through the
substrate 600 and make impressions on the FPL layer during
lamination.
[0059] The subsequent formation of the conductive traces may be
carried out in various fashions. In some embodiments, conductive
traces may be printed onto the reverse side beginning at the vias
and extend according to a pre-determined layout for routing all of
the lines from the pixel locations, without crossing, to one
condensed area that matches the pad pitch for the electronics to be
attached to the device. The printing of the conductive traces may
be accomplished manually for small numbers of backplane units, or
alternatively, an XY plotting machine with controlled dispensing of
printable conductive material may be used. Camera vision alignment
may be adopted to locate the vias and a XY plotter may be aligned
to that location to start drawing the conductive traces. It should
be appreciated that other trace producing methods commonly used in
the industry can be conveniently adopted, methods such as, but not
limited to, inkjet with conductive inks, rollers, tapes, etc. Some
examples of suitable trace materials are silver or carbon filled
printing inks. In this fashion, no global alignment may be required
to create the conductive traces. For example, local alignment may
be perfectly sufficient to places the traces to connect the vias to
a driver circuit. By not having to perform global alignments, large
sized (e.g., backplanes larger than 24 inches by 48 inches in
sizes) backplanes can be conveniently assembled because global
alignments can be hard to design for and expensive to perform.
[0060] In some other embodiment, the conductive traces may be
fabricated (e.g., printed) as a conductive interconnect layer. The
conductive interconnect layer may be produced separately from the
substrate 600 and the pixel conductor layer 500, and to be
assembled together when a display tile is being assembled.
[0061] Alternatively, conductive traces may be etched or scribed
onto a continuous conductive layer, similar to the patterning of
the driving electrodes 511-517 mentioned above. In some
embodiments, a continuous layer of conductive material may be
coated on the reverse side of the substrate 600. After the FPL
stack has been laminated onto the driving electrodes 511-517,
conductive traces may be etched into the continuous conductive
layer with a laser such that each conductive trace is electrically
isolated but not cutting into the substrate enough to cut through
or make it fragile. FIG. 7 illustrates an exemplary reverse side
conductor layer 700 with conductive traces 701-707. The conductor
layer 700 may be produced as a printed layer of conductive
circuitry, or by etching onto a continuous layer of conductive
material. In the case it is produced by etching, the cutting of
each conductive trace can include the via for the driving electrode
and a circular structure around the via adding the width of the
conductive trace around each via to ensure continuity to that
driving electrode. The alignment to each via may be accomplished
with a camera vision alignment system to find and align to each via
to locate the conductive trace path. The conductive traces 701-707
can extend in a pre-determined layout for routing all of the lines
from the pixel locations, without crossing, to one condensed area
that matches the pad pitch for the electronics to be attached to
the device.
[0062] For conductive fabric designs, it may be convenient to
firstly produce patterns for the driving electrodes and the
conductive traces, then paste them onto a substrate which could be
a fabric or film depending on the requirements of the display
application. Other suitable substrate material include PET,
Polyethylene naphthalate (PEN), cyclic olefins, paper, fabrics,
polyimide, or polycarbonate, etc.
[0063] In general, variations can be made to the backplane assembly
processes described above while still produce backplanes that are
substantially comparable in performances. For example, roll to roll
machines may be used to assemble backplanes that are in accordance
with the subject matter presented herein. In some embodiments,
continuous rolls of substrate coated with conductive materials can
be processed at multiple assembling stations including a laser
cutting/etching station and a XY plotting station, both equipped
with camera vision alignment systems. These two stations may be
distinct units or may be part of a single assembly station (e.g.,
both the laser cutter and the plotter can be part of an XY gantry
system). Furthermore, a roll to roll machine may further include a
station for heated lamination of ink FPL or other materials for
assembling display units. This arrangement can be advantageous for
at least the reason that the conductive traces can now be radiation
cured (e.g., UV cured) at the roll to roll machine, which saves
production time and cost by not having to use conventional heat
drying ovens.
[0064] In another embodiment, vias can be cut in a substrate roll
prior to the deposition of conductive materials, which permits the
filling of the vias using the deposited conductive material. In
this fashion, a separate assembling step to fill the vias may be
eliminated, further reducing production cost.
[0065] In yet another embodiment, vias may be left unfilled prior
to the lamination of the FPL to a display stack. The subsequent
dispensing of the conductive traces to the reverse side of the
substrate can in effect fulfill the vias to provide connection
between the driving electrodes and the conductive traces.
[0066] It should be appreciated that the pixel conductor layer, a
substrate layer and a reverse side conductor layer presented above
may be produced using flexible material, resulting in a display
tile that is bendable or flexible. In addition, the flexible nature
and robustness of the electrophoretic material enables the display
tile to be not only flexible, but capable of having multiple
curvatures. FIG. 8A illustrates one such flexible display tile 800.
The display tile 800 shown here may be sufficiently flexible to be
curved to a half-circular shape, where the tile's 800 front
electrode 804 may be produced using flexible material common
adopted in the industry. The pixel conductor layer 808, the
substrate layer 810 and the reverse side conductor layer 812 all
may be fabricated from materials sufficiently flexible to support a
layer of electrophoretic display material 806. The curved shape of
display tile 800 produces a space 814 adjacent to the reversed side
conductor layer 812 such that when assembled to a mounting
structure similar to the one illustrated in FIG. 2 a controller
apparatus (e.g., display controller or control circuit) may be
positioned or housed in that space 814, hiding from the view and
preserves the overall compactness of the overall display
apparatus.
[0067] In another embodiment shown in FIG. 8B, a flexible display
tile 802 may include multiple curvatures. The multiple layers of
the display tile 802 (e.g., the front electrode 816, the
electrophoretic material layer 816, the pixel conductor layer 820,
the substrate layer 822 and the reverse side conductor layer 824)
may be sufficiently flexible to assume various curvatures to suit a
designer's needs.
[0068] FIG. 9 illustrates a flexible display tile 908 that is
similar to the one presented in FIG. 8B being assembled onto a
mounting structure 900. The mounting structure 900, as discussed
above, may include a conductive interconnect layer 904 with
conductive traces for providing electrical connections to the
display tile 908. A printed graphic layer 902 may be positioned
between the interconnect layer 904 and the display tile 908 for
insulation. A connector 906 may be used to connect the display tile
908 to the interconnect layer 904. The connector 906 may have a
short wire for flexibility, or may be a snap on type connector, or
any connector commonly adopted in the industry, saving a user from
having to use cables to connect individual tiles to the mounting
structure.
[0069] From the foregoing, it will be seen that the present
invention provides means for inexpensive customization and quick
turn-around manufacturing of tiled display systems or apparatus.
The present invention eliminates the need for labor-intensive
custom cable fabrication and greatly simplifies the installation
process. The subject matter described herein also eliminates the
need for cable management and improves the aesthetics of the entire
installation process. Also reduced is the overall thickness of the
display apparatus, as there is no more need for extra spaces for
passing cables behind the display tiles. Furthermore, this
invention also allows for tiles to be placed non-adjacent to each
other, as the electrical connections are hidden behind the printed
graphics layer.
[0070] It will be apparent to those skilled in the art that
numerous changes and modifications can be made to the specific
embodiments of the invention described above without departing from
the scope of the invention. Accordingly, the whole of the foregoing
description is to be interpreted in an illustrative and not in a
limitative sense.
* * * * *