Electro-optical display device

Abstract

A display device has a plurality of display surfaces controlled by a controller, the display device having a mounting substrate for mounting the plurality of display surfaces. The mounting structure has a conductor layer for providing electrical connections to the plurality of display surfaces. The display device can also have at least one display surface that is sufficiently flexible to have a curvature, wherein the curvature creates a space between the at least one display surface and the mounting structure to accommodate the controller.

Description

[0001] Reference to Related Applications

[0002] This application claims priority to U.S. provisional application 62 / 348,801 filed June 10, 2016. The entire contents of the above-mentioned application are incorporated herein by reference. TECHNICAL FIELD

[0003] The present invention relates to electro-optic display devices. More particularly, the present invention provides means for assembling multiple electro-optic displays into larger display devices in a convenient manner. BACKGROUND

[0004] For some display applications, it can be desirable to assemble multiple electro-optic displays together to form a larger display screen. In order to connect multiple displays, a set of connecting cables is typically required for connecting each display to an electrical driver unit. In addition, one or more alignment frame structures are required to properly position the displays. The overall assembly of the displays typically requires careful measurement and precise placement of the individual displays. In operation, the connecting cables are highly customized to the individual display device design and, in addition, the customized connecting cables can be time consuming to assemble and prone to error at installation, making this approach only suitable for small volume applications and prototypes. Alternatively, the display connection can include modular subcomponents that can be connected to one another to span the distance between each display and the driver unit. In this way, such an approach is only feasible for large volume applications where the reduced production cost can be amortized over the large number of display devices produced.

[0005] The subject matter presented herein provides means for conveniently and at low cost assembling multiple displays into display devices in a variety of configurations. SUMMARY

[0006] The subject matter presented herein provides display devices having multiple display surfaces controlled by a controller, the display device having a mounting substrate for mounting the multiple display surfaces, the mounting structure having a conductor layer for providing electrical connections to the multiple display surfaces. The display device further includes at least one display surface that is flexible enough to have a curvature, wherein the curvature creates a space between the at least one display surface and the mounting structure to accommodate the controller. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 An electrophoretic image display according to the subject matter presented herein is shown;

[0008] Figure 2 An exemplary mounting structure for assembling multiple displays according to the subject matter presented herein is shown;

[0009] Figure 3a set of conductive interconnects according to the subject matter presented herein is shown; and

[0010] Figure 4 a printed graphic layer according to the subject matter presented herein is shown;

[0011] Figure 5 an exemplary pixel conductor layer of a display tile having a plurality of irregularly shaped pixel drive electrodes according to the subject matter presented herein is shown;

[0012] Figure 6 an exemplary substrate of a display tile according to the subject matter presented herein is shown;

[0013] Figure 7 a backside conductor layer having conductive traces according to the subject matter presented herein is shown;

[0014] Figure 8A and 8B a flexible display tile having various curvatures is shown; and

[0015] Figure 9 a flexible display tile mounted to a mounting structure is shown. DETAILED DESCRIPTION

[0016] The subject matter presented herein relates to apparatuses for assembling a plurality of electro-optic displays. Such apparatuses can include a conductive interconnect layer having a set of printed conductive interconnects for connecting a plurality of displays and a printed graphic overlay for aligning the displays. The electro-optic displays of the present subject matter are particularly, but not exclusively, intended for use in particle-based electrophoretic displays in which one or more types of electrically charged particles are suspended in a liquid and move through the liquid under the influence of an electric field to change the appearance of the display.

[0017] The term "electro-optic" as applied to a material or a display, is used herein in its conventional meaning, to refer to a material having first and second display states differing in at least one optical property, the material being capable of being switched 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 can be another optical property, such as optical transmission, reflectance, luminescence, or, where the display is for machine reading, pseudo-color in the sense of a change in reflectance of electromagnetic wavelengths outside the visible range.

[0018] 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 between dark and light states that, unlike the case of a simple bistable display, does not necessarily evolve over time toward one of the two extreme states. For example, a pixel having a gray state might remain in its gray state even after its addressing pulse has terminated. Similarly, a gray state might refer to a state that is not exactly intermediate the optical states of the two extreme states. It can be preferred to maintain the term "gray state" even though the state in question is outside the range of states that are considered "gray" in conventional usage. This usage of the term "gray state" is likely to facilitate understanding of the various display technologies disclosed herein. It must be emphasized that like a "black" display for which the light transmission is about 0% even as viewed through clear optics, and a "white" display for which the light transmission is about 100% even as viewed through clear optics, a gray display can also be about as bright or darker than a typical internal ambient light in a typical viewing environment. A display having a gray state that is substantially intermediate its lightest and darkest states can be preferred for certain applications, because such a display can provide additional contrast without consuming more power than a display that is either solely white or solely black.

[0019] Some electro-optic materials are solid or solid-like in the sense that they have a solid or solid-like external surface, although they can and often do have internal voids or spaces filled with air and / or liquid. Such displays using solid or solid-like electro-optic materials can be referred to herein for convenience as "solid electro-optic displays". Thus, the term "solid electro-optic display" is used herein to refer to any display that uses electro-optic materials, including displays using rotating bichromal members, encapsulated electrophoretic displays, microcell electrophoretic displays, and electrowetting displays.

[0020] The terms "bistable" and "bistability" are used herein in their conventional meaning in the imaging 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 to assume its first or second display state it is stable in that state and does not spontaneously change to its other state in the absence of an applied field to induce such a change. Some electro-optic media and displays can have three or more display states in which case the term bistable is not applicable. The term "bistable" is used herein to refer to displays having a bistable electro-optic medium, and the term "bistability" is used herein to refer to the property of such a medium. It is to be appreciated that the terms "bistable" and "bistability" can be used in the singular or the plural depending on the context.

[0021] 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. Patents 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 used to refer to the three types of electro-optic displays described in these patents, since the rotating member is not necessarily a ball). Such a display uses a large number of small bodies (typically spheres or cylinders) which are suspended inside a matrix and which include two or more portions having different optical characteristics. The appearance of the display is changed by applying an electric field to the display, thus rotating the bodies to various positions and changing which portion of the body is seen through the viewing surface. This type of electro-optic medium is typically bistable.

[0022] 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 and a plurality of dye molecules attached to the electrode, at least some of the dye molecules being capable of reversible color change; 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. This type of nanochromic film has been described, for example, in U.S. Patents Nos. 6,301,038; 6,870,657; and 6,950,220. This type of medium is also typically bistable.

[0023] Another type of electro-optic display is an electrowetting display, developed by Philips, which is described in Hayes, R. A., "Video-Speed Electronic Paper Based on Electrowetting", Nature, 425, 383-385 (2003). It has been shown that such an electrowetting display can be made bistable by using a three-layer structure; see U.S. Patent No. 7,420,549.

[0024] Another type of electro-optic display that has been the subject of intense research and development efforts for many years is the 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. However, these displays have persistent image problems, such as image sticking, i.e., temporary images that appear to persist after the cause of their appearance has been removed. These displays have also suffered from slow switching times, indicating that there are limitations inherent in the underlying physical processes involved.

[0025] 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 operate using a gaseous fluid; see for example Kitamura, T. et al., "Electronic paper based on electrophoretic

[0026] A number of patents and applications assigned to, or in the public domain of, the Massachusetts Institute of Technology (MIT) and E Ink Corporation, and references therein, relate to encapsulated electrophoretic media. Such encapsulated media comprise a plurality of small capsules, each of which comprises an internal phase and a capsule wall surrounding the internal phase, wherein the internal phase comprises an electrophoretically mobile particle suspended in a fluid. Typically, the capsules themselves are held in a binder to form a coherent layer positioned between two electrodes. The technology described in these patents and applications includes:

[0027] (a) electrophoretic particles, a fluid and a fluid additive; see for example U.S. Patents Nos. 7,002,728 and 7,679,814;

[0028] (b) Capsules, Adhesives, and Encapsulation Processes; see, e.g., U.S. Patent Nos. 6,922,276 and 7,411,719;

[0029] (c) Micro-Cell Structures, Wall Materials, and Methods of Forming Micro-Cells; see, e.g., U.S. Patent Nos. 7,072,095 and 9,279,906;

[0030] (d) Methods for Filling and Sealing Micro-Cells; see, e.g., U.S. Patent Nos. 7,144,942 and 7,715,088;

[0031] (e) Films and Subassemblies Containing Electro-Optic Materials; see, e.g., U.S. Patent Nos. 6,982,178 and 7,839,564;

[0032] (f) Backplanes, adhesive layers and other auxiliary layers used in displays and methods; see for example U.S. Patent 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 Application 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 Patent Publication No. WO 00 / 38000; European Patent Nos. 1,099,207 Bl and 1,145,072 Bl;

[0033] (g) Color formation and color adjustment; see for example U.S. Patent Nos. 7,075,502 and 7,839,564;

[0034] (h) Methods for driving displays; see for example U.S. Patent Nos. 7,012,600 and 7,453,445;

[0035] (i) Applications for displays; see for example U.S. Patent Nos. 7,312,784 and 8,009,348; and

[0036] (j) Non-electrophoretic displays as described in U.S. Patent No. 6,241,921 and U.S. Patent Application Publication No. 2015 / 0277160, and applications for encapsulation and microcell technology other than displays; see for example U.S. Patent Application Publication Nos. 2015 / 0005720 and 2016 / 0012710.

[0037] Many of the foregoing patents and applications recognize that the wall surrounding a discrete microcapsule in an encapsulated electrophoretic medium can be replaced by a continuous phase, thereby creating a so-called "polymer-dispersed electrophoretic display," in which the electrophoretic medium comprises a plurality of discrete droplets of electrophoretic fluid and a continuous phase of a polymer material, and the discrete droplets of electrophoretic fluid within such a polymer-dispersed electrophoretic display can be considered to be capsules or microcapsules, even though no discrete capsule membrane is associated with each individual droplet; see for example the aforementioned U.S. Patent No. 6,866,760. Thus, for the purposes of the present application, such polymer-dispersed electrophoretic media are considered to be a sub-class of encapsulated electrophoretic media.

[0038] A related type of electrophoretic display is a so-called "microcell electrophoretic display." In a microcell electrophoretic display, charged particles and fluid are not encapsulated within microcapsules, but instead remain in a plurality of cavities formed within a carrier medium, typically a polymer film. See for example U.S. Patent Nos. 6,672,921 and 6,788,449, both to Sipix Imaging.

[0039] While electrophoretic media are often opaque (e.g., in many electrophoretic media, the particles 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 the other is light-transmissive. See, for example, U.S. Patents Nos. 5,872,552; 6,130,774; 6,144,361; 6,172,798; 6,271,823; 6,225,971; and 6,184,856. A dielectrophoretic display, similar to an electrophoretic display but relying on changes in the electrical field strength rather than particle charge, can operate in a similar mode; see U.S. Patent No. 4,418,346. Other types of electro-optic displays can also be capable of operating in shutter mode. An electro-optic medium operating in shutter mode can be used in a multilayer construction for a full-color display; in such a construction, at least one layer adjacent the viewing side of the display operates in shutter mode to expose or hide a second layer further from the viewing side.

[0040] The subject matter described herein makes it possible to create display devices composed of multiple electro-optic displays or display tiles. In some embodiments, the multiple electro-optic displays or display tiles can be electrophoretic image displays (EPIDs). As Figure 1 An EPID 100 as shown can include a backplane 102 having a backplane pixel layer 108 containing multiple pixel drive electrodes, a front electrode layer 104, and a display layer 106. The display layer 106 can include electrophoretic pigment particles encapsulated in microcapsules or microcups. In Figure 1 Shown in the middle is a microcapsule including black and white electrophoretic pigment particles. The front electrode 104 can represent the viewing side of the EPID 100, in which case the front electrode 104 can be a transparent conductor such as indium tin oxide (ITO) (which in some cases can be deposited onto a transparent substrate such as polyethylene terephthalate (PET)). In Figure 1 In the display shown, the display layer 106 can be a particle-based medium including multiple microcapsules 110 between the layers 104 and 108. Within each capsule 110 is a liquid medium and one or more types of colored pigment particles including white pigment particles 112 and black pigment particles 114. The pigment particles 112 and / or 114 can be controlled (moved) with an electric field (e.g., generated by the electrodes on layers 108 and 104), thus causing the display 100 to operate as an electrophoretic display when addressed.

[0041] As indicated above, the subject matter presented herein provides a mounting structure for mounting an electro-optical display or display tile. The mounting structure may, in some embodiments, include a substrate for supporting a conductive interconnect layer. The substrate may be sufficiently flexible so that it can be rolled up or folded for transport. In some embodiments, 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 may be designed to resist puncture cutting by the laser and prevent etching. In still other embodiments, the conductive interconnect layer may be produced separately from the mounting substrate and assembled at a later time. The mounting structure may also include an additional substrate for covering a printed pattern of the conductive interconnect layer. The printed pattern substrate may be made of paper or plastic to act as an electrical insulator to protect the conductive interconnect layer below.

[0042] In one embodiment, once the size and geometry of the display are determined, the arrangement of the display and driver unit can then be determined (e.g., drawn) on the mounting structure. To connect the display and driver unit, computer-aided design software (e.g., AUTOCAD (registered trademark) or Altium) can be used to draw marker traces. The drawn traces can then be used as a template to manufacture the conductive interconnects. To mask the conductive interconnects, a printed graphic layer can be placed on top of the conductive interconnects. Holes or vias can be cut through the printed graphic layer to allow access to the conductive interconnects. It should be appreciated that the conductive interconnects can be manufactured independently, separately from the other layers, and individually. In this way, the designer has the freedom to design and manufacture the conductive interconnects to any suitable size and configuration. Thus, the designer is not bound by the limitations of any conductive trace generation equipment, but is free to manufacture interconnects of any size and shape suitable for the designer's customization.

[0043] Figure 2 2 shows a mounting structure 204 in which sixteen electro-optical displays or display tiles 202 can be assembled together to form a larger display device 200. In one example, the display tiles 202 can be arranged in a manner such as Figure 2 The mounting structure 204 is shown in a rectangular array (e.g., 4x4) in a manner similar to how tiles are positioned on a wall, with uniform spacing between the tiles. It should be appreciated that the rectangular shape of the display tiles 202 shown here is for illustrative purposes, as the tiles 202 can easily take on other geometric shapes. Furthermore, the subject matter disclosed herein enables the display tiles 202 to be arranged and assembled in a variety of configurations. In addition Figure 2 In addition to the ordered stacked configuration shown, the display tiles 202 can also be arranged, for example, with uneven spacing therebetween and in a disordered manner. In some embodiments, the display tiles 202 can be arranged according to a specific pattern to form a predetermined image. Alternatively, the designer can arbitrarily arrange the display tiles to form a specific pattern (e.g., an abstract image, etc.).

[0044] In addition, each tile can be given a designation code to match a particular location on the mounting structure 204. For example, a display tile (not shown) can be designated as IA to match a predetermined location IA on the mounting structure 204, and the end user can simply match the tile IA with the predetermined location IA when assembling the display device 200.

[0045] In some embodiments, the mounting structure 204 can include a substrate for supporting the conductive interconnect layer. The support substrate can be made of plastic such as polyethylene terephthalate (PET) and have a thickness of at least 2 mils (51 μm - preferably 5 mils (127 μm) or more and be flexible enough to be rolled up or folded. In some embodiments, the conductive interconnect layer can be scribed using an energy or particle (e.g., laser) beam, and the support substrate is preferably able to withstand the cutting of the laser. The conductive interconnects (e.g., traces and / or pads) connecting the display tiles can sometimes be made by drawing traces and / or pads between the tiles using a continuous conductor such as carbon black or metal filled ink. Alternatively, the interconnect traces or pads can be mechanically or laser scribed from a conductive layer made of a material such as indium tin oxide (ITO) or sputtered metal (e.g., aluminum). In yet another embodiment, separate traces can be printed using a technique such as silk screening that can be suitable for high volume applications, where the tooling and other start-up costs can be amortized over time.

[0046] In addition, the mounting structure can also include another substrate for printed graphics, and this substrate can be disposed above the conductive interconnect layer. This printed graphics substrate layer can be made of paper or plastic and function as an electrical insulator to protect the underlying conductive interconnect layer as well as a printing surface for the printed graphics. The printed graphics can be produced using inkjet or laserjet printing for uniquely customized designs or gravure printing for high volume (non-customized) designs. The printed graphics can function as alignment markers during mounting as well as provide aesthetic appeal to the display device 200.

[0047] To assemble the display device 200, in a preferred embodiment, a designer can first determine the size and shape of the display tiles 202. The designer can then decide the arrangement of each tile, and where the conductive interconnects can be placed on each tile. The outline of the arrangement of the tiles 202 and their conductive interconnects can be drawn on the same layer as the printed artwork to simplify installation. Subsequently, the location of the driver unit of the display device can be determined. It is preferred that the driver unit be placed behind one of the display tiles 202. In some embodiments, the display tiles 202 can be curved outwardly away from the mounting structure 204, leaving room behind the tiles for the driver unit. Alternatively, the driver unit can be placed away from the tiles 202, for example, hidden behind a housing (e.g., a wainscot molding), folded around behind the mounting structure 204 (e.g., over the top tile), or at a location that is easily accessible by the display operator.

[0048] Once the arrangement of the display tiles 202 and the driver unit is determined, the marked traces that connect the driver unit outputs to the display tiles 202 can be drawn. The marked traces can be drawn using CAD software such as Autocad, Altium, PADS, or Adobe Illustrator. In some embodiments, fiducial marks can also be drawn to aid in later alignment of the printed artwork with the conductive interconnects (e.g., traces and / or pads). Subsequently, the conductive interconnects can be manufactured using the drawn marked traces as a template. Referring now to Figure 3 , a conductive interconnect layer 300 for providing electrical connections to the display tiles is shown. The conductive interconnect layer 300 can be manufactured by printing traces 302 and pads 304 on a media substrate (e.g., PET) or by scribing a conductive film (e.g., carbon, silver, aluminum, ITO, etc.) that has been deposited on a media substrate. Other methods of manufacturing the conductive interconnects 300 can be readily employed here depending on what manufacturing equipment is available to the user. It should be noted that the conductive interconnect layer 300 can be manufactured here separately from all other layers of the display device 100. In this way, the designer is free to utilize any method to produce the interconnect layer 300 and is not bound by any interconnect producing equipment. Thus, the designer can manufacture interconnects of any shape or size as he sees fit to accommodate his design. This allows the designer to freely produce display devices of various shapes and configurations and is not bound by the limitations of the manufacturing of conductive interconnects.

[0049] In use, each display tile can have a pre-assembled connector (e.g., a flat flexible connector) port, and matching connectors can be placed on the pads 304, in this way, when assembling the display device, the user can simply connect the connectors on each display tile to the matching connectors on the pads 304, eliminating the need to produce a connecting cable to connect multiple display tiles to a mounting structure, making the entire device more compact and convenient to assemble.

[0050] Now refer to Figure 4 , shows a printed graphic layer 400 produced on a dielectric substrate that may later be laminated to Figure 3 On the conductive interconnect layer 300 shown. On the printed graphics layer 400, the arrangement of the display tiles and driver units is outlined along with through holes 402 for the conductive interconnects. In addition, if multiple structures or surfaces are required, fiducial or alignment marks can also be drawn on this layer for aligning adjacent interconnect mounting structures. For aesthetic purposes, other graphic features such as artistic designs can be further included. Once manufactured, through holes or vias can be cut in this layer 400 to allow access to the conductive interconnects, where the driver units and display tiles can be connected. The through holes can be made using laser cutting, die cutters, scissors, etc. according to the designer's preference, and the electrical connections can be made using conductive pressure sensitive adhesive pads, spring pins or electrical connections such as crimp pin / socket pairs (i.e. Nicomatic).

[0051] In a preferred embodiment, the printed graphics and conductive interconnects can be adhered (e.g., laminated) together or separately to a supporting substrate to create a monolithic mounting structure or surface. The display tiles can then be positioned onto the mounting structure at their intended locations. Optionally, a mounting frame can also be provided, to which the mounting structure and display tiles can be attached.

[0052] In addition, the topics presented in this paper also provide connections to Figure 2 . An exemplary display tile may include a pixel conductor layer, a substrate layer and a reverse conductor layer, wherein the substrate layer may be located between the pixel conductor layer and the reverse conductor layer. Drive electrodes for display pixels or pixel segments may be defined and manufactured on the pixel conductor layer. In a preferred embodiment, the drive electrodes are first patterned on the pixel conductor layer using an energy or particle beam (e.g., laser scribing), wherein the laser scribing allows the manufacture of drive electrodes of various sizes and geometries without the use of complex machinery. Subsequently, through-holes may be created through the substrate layer, and conductive traces may be drawn on the reverse conductor layer, wherein the conductive traces are used to transmit a voltage or drive waveform to the drive electrodes through the through-holes. In this way, the backplane is assembled without having to use size-limiting techniques such as photolithography or global alignment - techniques typically required for screen printing or PCB manufacturing. Thus, large-scale backplanes with drive electrodes of variable sizes can be assembled conveniently and inexpensively.

[0053] In some implementations, specialized display applications will require displays to utilize pixels or pixel segments of irregular geometries.The present subject matter enables the inexpensive assembly of display tiles having a plurality of irregularly shaped display pixel segments. Figure 5 5. The pixel conductor layer 500 of a display tile having a plurality of irregularly shaped pixel segments is shown.Figure 5 As shown, the pixel conductor layer 500 may include a plurality of variable-sized drive electrodes 511-517 for driving a plurality of irregularly shaped pixel segments (not shown), wherein the shape and position of the drive electrodes 511-517 will match the shape and position of the corresponding pixel segments. In some embodiments, the pixel conductor layer 500 can be formed by applying a continuous layer of a conductive material such as ITO to a substrate. Other conductive materials can also be sputtered onto the substrate to form a continuous layer, 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 materials such as copper, nickel, aluminum, silver nanowires, and printed silver can also be used depending on the specific needs of the display application.

[0054] According to some embodiments of the present subject matter, the display tile assembly process may include having a continuous layer of conductive material scribed by a laser to pattern drive electrodes 511-517 of various shapes. The scribes may cut deep enough into the conductive material layer to electrically isolate each drive electrode, but not so deep as to cut through the underlying substrate or substantially weaken the substrate so that it becomes brittle. Laser scribing allows the patterning of drive electrodes in various geometric configurations without having to perform photolithography or global alignment, which may be prohibitively expensive for large-scale displays. Figure 5 Also shown are star-shaped drive electrodes 520 and circular drive electrodes 522, but it will be appreciated that other geometries may be readily patterned using laser scribing or other comparable etching methods commonly employed in the industry.

[0055] Once the drive electrodes are patterned, vias may be created through the substrate to connect the drive electrodes to driver circuitry (not shown). Figure 6 An exemplary substrate layer 600 according to the subject matter presented herein is shown. In some embodiments, the substrate layer 600 can be made using materials such as PET, polyethylene naphthalate (PEN), cyclic olefins, paper, fabric, polyimide, or polycarbonate. Figure 5 The electrical connection of the drive electrodes 511-517 shown can be achieved by creating one or more through-holes 621-627 for each drive electrode 511-517 through the substrate layer 600. The through-holes 621-627 can be created by cutting through the substrate layer 600 using a laser, but it will be appreciated that mechanical drilling or other puncture methods commonly used in the art can be readily employed. In some embodiments, the through-holes cut into the drive electrodes can be at least 200 μm in diameter and typically no greater than 3 mm to minimize the appearance of the holes in the final display. It will be appreciated that in other embodiments, the through-holes can be formed before the drive electrodes are patterned, for example, the substrate can be pre-fabricated with through-holes in appropriate locations configured for backplane assembly.

[0056] Once the vias 621-627 are created, a porous paper can be used behind the substrate and a vacuum pull on the porous paper can be used to disperse conductive material (not shown) into the vias 621-627. The vacuum force will pull the conductive material through the vias 621-627 and either plate the sides of the vias 621-627 or fill the volume of the vias 621-627, connecting the drive electrodes 511-517 to the backside of the substrate 600. Preferably, the completed vias have a surface that is coplanar with both the pixel conductor layer and the backside conductor layer to avoid bumps from too much filler or lamination voids due to insufficient via filling. In some embodiments, the vias 621-627 can be filled with a hot melt adhesive that has a melting temperature around the lamination temperature of the electrophoretic ink material (e.g., 250F) as long as the hot melt adhesive has a flow viscosity low enough to prevent ink capsule breakage.

[0057] The properly filled vias 621-627 can provide an electrical connection between the drive electrodes 511-517 and conductive traces formed on the backside of the substrate 600 (i.e., the side opposite the pixel conductor layer). In some embodiments, an ink FPL stack (not shown) can first be laminated to the drive electrodes 511-517 prior to the formation of the conductive traces. This is done in such a way that the thickness of the traces will not press through the substrate 600 and create an indentation in the FPL layer during lamination.

[0058] The subsequent formation of the conductive traces can be done in various ways. In some embodiments, the conductive traces can be printed onto the backside starting at the vias and extending according to a predetermined layout for routing all the lines from the pixel locations to a concentrated area that matches the pad pitch of the electronics to be attached to the device without crossing over. The printing of the conductive traces can be done manually for small backplane units or, alternatively, an XY plotter with controlled dispensing of a printable conductive material can be used. Camera vision alignment can be employed to locate the vias and the XY plotter can be aligned to that location to start plotting the conductive traces. It should be recognized that other trace generation methods commonly used in the industry can be conveniently employed, such as, but not limited to, inkjet using conductive ink, rollers, tape, etc. Some examples of suitable trace materials are printed inks filled with silver or carbon. In this way, global alignment can not be needed to create the conductive traces. For example, local alignment can be entirely sufficient to lay out the traces to connect the vias to the driver circuitry. By not having to perform global alignment, large size backplanes (e.g., backplanes larger than 24 inches by 48 inches in size) can be conveniently assembled since global alignment can be difficult to design and expensive to perform.

[0059] In some other embodiments, the conductive traces can be fabricated (e.g., printed) as a conductive interconnect layer. The conductive interconnect layer can be produced separately from the substrate 600 and the pixel conductor layer 500 and assembled together when the display tiles are assembled.

[0060] Alternatively, the conductive traces can be etched or scribed into a continuous conductive layer, similar to the patterning of the drive electrodes 511-517 mentioned above. In some embodiments, a continuous layer of conductive material can be coated on the reverse side of the substrate 600. After the FPL stack is laminated onto the drive electrodes 511-517, the conductive traces can be etched into the continuous conductive layer using a laser such that each conductive trace is electrically isolated, but not cut into the substrate enough to cut through or make it brittle. Figure 7 An exemplary reverse side conductor layer 700 with conductive traces 701-707 is shown. The conductor layer 700 can be produced as a printed layer of conductive circuitry or by etching into a continuous layer of conductive material. In the case that it is produced by etching, the cut of each conductive trace can include a via for a drive electrode and a circular structure around the via that increases the width of the conductive trace around each via to ensure continuity to that drive electrode. Alignment with each via can be accomplished using a camera vision alignment system to find and align each via to position the conductive trace path. The conductive traces 701-707 can extend in a predetermined layout for routing all the lines from the pixel locations to one area of concentration without crossing, which matches the pad pitch of the electronics to be attached to the device.

[0061] For conductive fabric designs, it can be convenient to first produce the patterns of drive electrodes and conductive traces and then affix them to a substrate, which can be a fabric or a film depending on the needs of the display application. Other suitable substrate materials include PET, polyethylene naphthalate (PEN), cyclic olefins, paper, fabric, polyimide, or polycarbonate, among others.

[0062] In general, changes can be made to the backplane assembly processes described above while still producing a backplane that is substantially comparable in performance. For example, a roll-to-roll machine can be used to assemble a backplane according to the subject matter presented herein. In some embodiments, a continuous roll of a substrate coated with a conductive material can be processed at multiple assembly stations including a laser cutting / etching station and an XY plotter station, both equipped with a camera vision alignment system. The two stations can be different units or can be part of a single assembly station (e.g., the laser cutter and plotter can be part of an XY gantry system). In addition, the roll-to-roll machine can also include a station for heat lamination of ink FPLs or other materials for assembling the display unit. This arrangement can be advantageous at least because 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 a conventional heat drying oven.

[0063] In another embodiment, the vias can be cut with the substrate roll prior to deposition of the conductive material, which allows the vias to be filled with the deposited conductive material. In this way, a separate assembly step for filling the vias can be eliminated, further reducing production costs.

[0064] In yet another embodiment, the vias may be left unfilled prior to lamination of the FPL to the display stack.Subsequent distribution of conductive traces to the reverse side of the substrate may actually implement the vias to provide connections between the drive electrodes and the conductive traces.

[0065] It will be appreciated that flexible materials may be used to create the pixel conductor layer, substrate layer and reverse conductor layer proposed above, resulting in bendable or flexible display tiles. Furthermore, the flexible nature and robustness of electrophoretic materials enable display tiles to be not only flexible but also to have multiple curvatures. Figure 8A One such flexible display tile 800 is shown. The display tile 800 shown here can be flexible enough to be bent into a semicircular shape, wherein the front electrode 804 of the tile 800 can be made of flexible materials commonly used in the industry. The pixel conductor layer 808, substrate layer 810, and back conductor layer 812 can all be made of materials that are flexible enough to support the electrophoretic display material layer 806. The curved shape of the display tile 800 creates a space 814 adjacent to the back conductor layer 812, so that when assembled with Figure 2 When the mounting structure is similar to the mounting structure shown, the controller device (such as a display controller or control circuit) can be located or accommodated in that space 814, out of sight and maintaining the overall compactness of the overall display device.

[0066] exist Figure 8B In another embodiment shown, the flexible display tile 802 can 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 back conductor layer 824) can be flexible enough to assume various curvatures to suit the designer's needs.

[0067] Figure 9 Shown is a similar assembly to that on the mounting structure 900. Figure 8BThe flexible display tile 908 is shown in cross-section. The mounting structure 900 as discussed above can include a conductive interconnect layer 904 with conductive traces for providing electrical connections to the display tile 908. A printed graphic layer 902 can be located between the interconnect layer 904 and the display tile 908 for insulation. Connectors 906 can be used to connect the display tile 908 to the interconnect layer 904. The connectors 906 can have short wires for flexibility, or can be snap-in type connectors or any connectors commonly used in the industry that free the user from having to use cables to connect individual tiles to the mounting structure.

[0068] From the foregoing, it will be seen that this application provides a means for inexpensive customization and rapid turn-around manufacturing for tiled display systems or devices. The application eliminates the need for labor-intensive custom cable manufacturing and greatly simplifies the installation process. The subject matter described herein also eliminates the need for cable management and improves the aesthetics of the overall installation process. The overall thickness of the display device is also reduced because additional space is no longer needed to pass cables behind the display tiles. In addition, the application also allows tiles to be placed non-adjacently to each other because the electrical connections are hidden behind the printed graphic layer.

[0069] It will be apparent to those skilled in the art that many changes and modifications can be made to the particular implementations of the application described above without departing from the scope of the application. Thus, the foregoing description is by way of example only, not limiting.

Claims

1. A method for forming a patterned electrophoretic display, comprising: providing a substrate coupled to the conductor layer; patterning the conductor layer using laser scribing to create a plurality of patterned drive electrodes; providing a front plane laminate (FPL) comprising a front electrode and a display layer, the display layer comprising encapsulated electrophoretic pigment particles in a fluid; coupling the front plane laminate to the substrate; producing a reverse conductor layer by etching through a continuous layer of conductive material; coupling the reverse conductor layer to the substrate layer on a side of the substrate opposite the side of the substrate coupled to the conductor layer, wherein the substrate includes conductive vias between the plurality of patterned drive electrodes and the reverse conductor layer and the reverse conductor layer forms conductive traces between a voltage source and the patterned drive electrodes; Each conductive trace is cut to include a circular structure around each conductive via, the conductive traces extending in a predetermined layout for routing all lines from the pixel location to a collection area without crossing, the collection area matching the pad pitch of the electronic device.

2. The method according to claim 1, wherein The patterned driving electrodes are formed by patterning the conductor layer instead of patterning the substrate layer.

3. The method according to claim 1, wherein The patterned driving electrodes are formed by simultaneously patterning the conductor layer and the substrate layer.

4. The method according to claim 1, wherein The substrate includes polyethylene terephthalate (PET), polyethylene naphthalate (PEN), cyclic olefin, paper, fabric, polyimide or polycarbonate.

5. The method according to claim 1, wherein The conductor layer includes indium tin oxide (ITO), gold, nickel boron, carbon, carbon nanotubes, graphene, or poly (3,4-ethylenedioxythiophene) (PEDOT).

6. A patterned electrophoretic display comprising, from top to bottom: a front electrode comprising a transparent conductor; a display layer comprising encapsulated electrophoretic pigment particles in a fluid; a plurality of patterned drive electrodes formed by scribing a patterned conductor layer with a laser, wherein the front electrode overlaps two or more of the patterned drive electrodes; as well as a substrate layer coupled to the conductor layer; a counter conductor layer coupled to the substrate layer on a side of the substrate opposite the side of the substrate coupled to the conductor layer, the counter conductor layer being produced by etching through a continuous layer of conductive material, wherein the substrate layer includes vias between the plurality of patterned drive electrodes and the counter conductor layer and the counter conductor layer forms conductive traces between a voltage source and the patterned drive electrodes; Each conductive trace cut includes a circular structure around each conductive via, the conductive traces extending in a predetermined layout for routing all lines from the pixel location to a collection area without crossing, the collection area matching the pad pitch of the electronic device.

7. The patterned electrophoretic display according to claim 6, wherein: The through-hole is filled with a conductive material.

8. The patterned electrophoretic display according to claim 6, wherein: The electrophoretic pigment particles and the fluid are encapsulated in microcapsules.

9. The patterned electrophoretic display according to claim 6, wherein: The electrophoretic pigment particles and the fluid are encapsulated in microcells.

10. The patterned electrophoretic display according to claim 6, wherein: The electrophoretic pigment particles are charged and move through the fluid under the influence of an electric field to change the appearance of the patterned electrophoretic display.

11. The patterned electrophoretic display according to claim 6, wherein: The patterned driving electrodes are formed by patterning the conductor layer after the conductor layer is coupled to the substrate layer.

12. The patterned electrophoretic display according to claim 11, wherein: The patterned driving electrodes are formed by patterning the conductor layer instead of patterning the substrate layer.

13. The patterned electrophoretic display according to claim 11, wherein: The patterned driving electrodes are formed by simultaneously patterning the conductor layer and the substrate layer.

14. The patterned electrophoretic display according to claim 6, wherein: The substrate includes polyethylene terephthalate (PET), polyethylene naphthalate (PEN), cyclic olefin, paper, fabric, polyimide or polycarbonate.

15. The patterned electrophoretic display according to claim 6, wherein: The conductor layer includes indium tin oxide (ITO), gold, nickel boron, carbon, carbon nanotubes, graphene, or poly (3,4-ethylenedioxythiophene) (PEDOT).

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