Flexible segmented electro-optic displays and methods of manufacture

Abstract

A flexible segmented electro-optic display and a method for manufacturing the same are disclosed. The display includes an electroactive layer having a front viewing side and an opposite rear side. The electroactive layer includes an encapsulated electrophoretic dielectric. A transparent common electrode layer is superimposed on the front viewing side of the electroactive layer. A plurality of display segment electrodes are directly adjacent to the rear side of the electroactive layer. Each of the display segment electrodes is associated with an adjacent portion of the encapsulated electrophoretic dielectric. A processor die is electrically connected to each of the plurality of display segment electrodes to apply a voltage to a selected display segment electrode, thereby driving the respective associated portions of the encapsulated electrophoretic dielectric between different optical states. A protective seal encapsulates the electroactive layer, the transparent common electrode layer, the plurality of display segment electrodes, and the processor die.

Description

Technical Field

[0001] [Interactive Reference Materials for Related Applications] This application claims priority to U.S. Provisional Patent Application No. 63 / 622,686, filed January 19, 2024, entitled "Flexible Segmented Electro-optic Display and Method of Manufacturing the Same Thereof," the entire contents of which are incorporated herein by reference.

[0002] This application generally relates to flexible segmented electro-optic displays and methods for manufacturing the same. More specifically, this application relates to flexible segmented electrophoretic displays having display segment electrodes that are directly printed onto one side of the electroactive layer adjacent to the device, rather than printed on a backplane laminated to the electroactive layer. Prior Technology

[0003] Electro-optic displays can include encapsulated electrophoretic media and various other types of electro-optic media that are "solid" in the sense that they have a solid outer surface, but these media may and often do have internal cavities containing fluids (liquids or gases). Such "solid-state electro-optic displays" include encapsulated electrophoretic displays, encapsulated liquid crystal displays, and other types of displays discussed below.

[0004] An electro-optic display comprises a layer of electro-optic material. This term, used herein in its conventional sense in imaging technology, refers to an electroactive material having at least a first and a second display state, which differ in at least one optical property. The material is changed from its first display state to its second display state by applying an electric field to the material. While the optical property is typically color perceptible to the human eye, it can be another optical property, such as light transmission, reflection, emission, or, in the case of a display intended for machine reading, pseudo-color in the sense of a change in reflectivity at electromagnetic wavelengths outside the visible light range.

[0005] The terms "bistable" and "bistability" are used herein in their conventional sense to refer to a display comprising display elements having first and second display states that are different in at least one optical property, and to present either the first or second display state after any given element is driven by an electrically addressed pulse of finite duration, and that state persists at least several times, for example, at least four times, after the addressing pulse terminates; the addressing pulse requires a minimum duration to change the state of the display element. U.S. Patent No. 7,170,670 shows that some particle-based electrophoretic displays with grayscale capabilities are stable not only in their extreme black and white states but also in their intermediate gray states, and so are some other types of electro-optical displays. This type of display may be appropriately called multi-stable rather than bistable, but for convenience, the term "bistable" may be used herein to encompass both bistable and multi-stable displays.

[0006] Several types of electro-optic displays are known. One type of electro-optic display is, for example, the rotating bichromal member type described in U.S. Patents 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 because in some of the aforementioned patents, the rotating member is not spherical.) Such a display uses a large number of small objects (typically spherical or cylindrical) having two or more parts with different optical properties and an internal dipole. These objects are suspended in liquid-filled bubbles within a matrix, wherein the liquid-filled bubbles allow the objects to rotate freely. By applying an electric field, these objects are rotated to various positions and the portion of these objects visible through a viewing surface is altered, thereby changing the display. This type of electro-optic medium is typically bistable.

[0007] Another type of electro-optic display uses an electrochromic medium, such as an electrochromic film in the form of a nanochromic film, comprising an electrode at least partially composed of a semiconductor metal oxide and a plurality of dye molecules with reversible color-changing capabilities 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 at., Adv. Mater., 2002, 14(11), 845. This type of nanochromic film is also described, for example, in U.S. Patents 6,301,038; 6,870,657; and 6,950,220. This type of medium is also typically bistable.

[0008] Particle-based electrophoretic displays are another type of electro-optical display in which charged particles move through a suspended liquid under the influence of an electric field. Such displays have been the subject of intensive research and development for several years. Compared to liquid crystal displays (LCDs), electrophoretic displays offer superior brightness and contrast, wide viewing angles, dual stability, and low power consumption. However, long-term image quality issues hinder their widespread adoption. For example, the particles constituting an electrophoretic display tend to settle, leading to a shorter lifespan for these displays.

[0009] As mentioned above, the electrophoretic medium requires the presence of a fluid. In most conventional electrophoretic media, this fluid system is liquid, but a gaseous fluid can be used to produce the electrophoretic medium; 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. Patent Application Publication No. 2005 / 0001810; European Patent Applications Nos. 1,462,847; 1,482,354; 1,484,635; 1,500,971; 1,501,194; 1,536,271; 1,542,067; 1,577,702; 1,577,703; and 1,598,694; and International Applications WO 2004 / 090626; WO 2004 / 079442; and WO 2004 / 001498. When such media are used in an orientation that allows particle settling (e.g., in the case of media arranged in a vertical plane), such gas-based electrophoretic media appear to be susceptible to the same type of problems caused by particle settling as those of liquid-based electrophoretic media. More precisely, particle sedimentation appears to be a more serious problem in gas-based electrophoretic media than in liquid-based electrophoretic media, because the lower viscosity of gas suspensions allows for faster sedimentation of these electrophoretic particles compared to liquid suspensions.

[0010] Numerous patents and applications, assigned to or in the name of the Massachusetts Institute of Technology (MIT) and E Ink Corporation, describe various techniques used in encapsulation electrophoresis and other electro-optic media. Such encapsulation media comprise a plurality of small capsules, each capsule comprising an internal phase of electrophoretically moving particles contained in a fluid medium and a capsule wall surrounding the internal phase. Typically, these capsules are held in a polymeric binder to form a coherent layer between two electrodes. The techniques described in these patents and applications include: (a) Electrophoretic particles, fluids, and fluid additives: see, for example, U.S. Patent Nos. 7,002,728 and 7,679,814; (b) Capsules, binders, and encapsulation processes: see, for example, U.S. Patent Nos. 6,922,276 and 7,411,719; (c) Cellular structure, wall material, and methods of forming microcells: see, for example, U.S. Patent Nos. 7,072,095 and 9,279,906; (d) Methods for filling and sealing microcells: see, for example, U.S. Patent Nos. 7,144,942 and 7,715,088; (e) Thin films and sub-assemblies containing electro-optic materials: see, for example, U.S. Patent Nos. 6,982,178 and 7,839,564; (f) Backplates, adhesive layers and other auxiliary layers used in displays, and methods thereof: see, for example, U.S. Patent Nos. 7,116,318 and 7,535,624; (g) Color formation and color adjustment: See, for example, U.S. Patent Nos. 6,017,584; 6,545,797; 6,664,944; 6,788,452; 6,864,875; 6,914,714; 6,972,893; 7,038,656; 7,038,670; 7,046,228; 7,052,571; 7,075,502; 7,167,155; 7,385,751; 7,492,505; 7,667,684; 7,684,108; 7,791,789; 7,800,813; 7,821,702; 7,839,564; 7,910,175; 7,952,7 90;7,956,841;7,982,941;8,040,594;8,054,526;8,098,418;8,159,636;8,213,076;8,363,299;8,422,116;8,441,714;8,441,716;8,466,852;8 ,503,063;8,576,470;8,576,475;8,593,721;8,605,354;8,649,084;8,670,174;8,704,756;8,717,664;8,786,935;8,797,634;8,810,899;8,830, 559;8,873,129;8,902,153;8,902,491;8,917,439;8,964,282;9,013,783;9,116,412;9,146,439;9,164,207;9,170,467;9,170,468;9,182,646;9,195,111;9,199,441;9,268,191;9,285,649;9,293,511;9,341,916;9,360,733;9,361,836;9,383,623; and 9,423,666; and U.S. Patent Application Publication No. 2008 / 004331 8;2008 / 0048970;2009 / 0225398;2010 / 0156780;2011 / 0043543;2012 / 0326957;2013 / 0242378;2013 / 0278995;2014 / 0055840;2014 / 0078576;2014 / 0340430;2014 / 0340736;2014 / 0362213;2015 / 0103394;2015 / 0118390;2015 / 0124345;2015 / 0198858;2015 / 0234250;2015 / 0268531;2015 / 0301246;2016 / 0011484; 2016 / 0026062; 2016 / 0048054; 2016 / 0116816; 2016 / 0116818; and 2016 / 0140909; (h) Methods for driving a display: see, for example, U.S. Patent Nos. 5,930,026; 6,445,489; 6,504,524; 6,512,354; 6,531,997; 6,753,999; 6,825,970; 6,900,851; 6,995,550; 7,012,600; 7,023,420; 7,034,783; 7,061,166; 7,061,662; 7,116,466; 7,119,772; 7,177,066; 7,193,625; 7,202,847; 7,242,514; 7,259,744; 7,304,787; 7,3 12,794;7,327,511;7,408,699;7,453,445;7,492,339;7,528,822;7,545,358;7,583,251;7,602,374;7,612,760;7,679,599;7,679,813;7,683, 606;7,688,297;7,729,039;7,733,311;7,733,335;7,787,169;7,859,742;7,952,557;7,956,841;7,982,479;7,999,787;8,077,141;8,125,501 ;8,139,050;8,174,490;8,243,013;8,274,472;8,289,250;8,300,006;8,305,341;8,314,784;8,373,649;8,384,658;8,456,414;8,462,102;8, 514,168;8,537,105;8,558,783;8,558,785;8,558,786;8,558,855;8,576,164;8,576,259;8,593,396;8,605,032;8,643,595;8,665,206;8,681 ,191;8,730,153;8,810,525;8,928,562;8,928,641;8,976,444;9,013,394;9,019,197;9,019,198;9,019,318;9,082,352;9,171,508;9,218,77 3;9,224,338;9,224,342;9,224,344;9,230,492;9,251,736;9,262,973;9,269,311;9,299,294;9,373,289;9,390,066;9,390,661; and 9,412,314;and U.S. Patent Application Publications Nos. 2003 / 0102858; 2004 / 0246562; 2005 / 0253777; 2007 / 0091418; 2007 / 0103427; 2007 / 0176912; 2008 / 0024429; 2008 / 0024482; 2008 / 0136774; 2008 / 0291129; 2008 / 0303780; 2009 / 0174651; 2009 / 0195568; 2009 / 03227 21;2010 / 0194733;2010 / 0194789;2010 / 0220121;2010 / 0265561;2010 / 0283804;2011 / 0063314;2011 / 0175875;2011 / 0193840;2011 / 0193841;2011 / 0199671;2011 / 0221740;2012 / 0001957;2012 / 0098740;2013 / 0063333;2013 / 01 94250;2013 / 0249782;2013 / 0321278;2014 / 0009817;2014 / 0085355;2014 / 0204012;2014 / 0218277;2014 / 0240210;2014 / 0240373;2014 / 0253425;2014 / 0292830;2014 / 0293398;2014 / 0333685;2014 / 0340734;2015 / 0070744;2015 Patent applications numbered / 0097877;2015 / 0109283;2015 / 0213749;2015 / 0213765;2015 / 0221257;2015 / 0262255;2015 / 0262551;2016 / 0071465;2016 / 0078820;2016 / 0093253;2016 / 0140910; and 2016 / 0180777 (these patent applications may be referred to below as MEDEOD (method for driving an electro-optic display) applications); (i) Applications of displays: see, for example, U.S. Patent Nos. 7,312,784 and 8,009,348; and (j) Non-electrophoretic displays: see, for example, U.S. Patent No. 6,241,921 and U.S. Patent Application Publications Nos. 2015 / 0277160, 2015 / 0005720, and 2016 / 0012710.

[0011] Many of the aforementioned patents and applications recognize that the walls surrounding discrete microcapsules in an encapsulated electrophoretic medium can be replaced by a continuous phase, thereby producing a so-called polymer dispersion electrophoretic display; in such a display, the electrophoretic medium comprises electrophoretic fluids of a plurality of discrete droplets and a continuous phase of polymeric material, and recognizes that even without discrete capsule membranes associated with each individual droplet, the electrophoretic fluids of the discrete droplets within such a polymer dispersion electrophoretic display can be considered as capsules or microcapsules; see, for example, U.S. Patent No. 6,866,760. Thus, for the purposes of this application, such polymer dispersion electrophoretic media are considered a subtype of encapsulated electrophoretic media.

[0012] One related type of electrophoretic display is the so-called "microcellular electrophoresis display." In a microcellular electrophoresis display, instead of encapsulating charged particles and fluids in microcapsules, they are held within a plurality of cavities formed in a carrier medium (e.g., a polymeric membrane). See, for example, U.S. Patents 6,672,921 and 6,788,449.

[0013] Another type of electro-optic display is the electro-wetting display developed by Philips and described in Hayes, RA, et al., “Video-Speed ​​Electronic Paper Based on Electrowetting”, Nature, 425, 383-385 (2003). U.S. Patent No. 7,420,549 shows that such an electro-wetting display can be fabricated to be bistable.

[0014] Other types of electro-optic materials may also be used in various embodiments. Of particular interest are bistable ferroelectric liquid crystal displays (FLCs), which are known in this art.

[0015] Although electrophoretic media are typically opaque (because, for example, in many electrophoretic media, particles substantially block the transmission of visible light through the display) and operate in reflective mode, many electrophoretic displays can operate in a so-called "shutter mode," in which one display state is substantially opaque and another display state is transparent. See, for example, U.S. Patents 6,130,774 and 6,172,798 and U.S. Patents 5,872,552, 6,144,361, 6,271,823, 6,225,971, and 6,184,856. Dielectrophoretic displays (which are similar to electrophoretic displays but depend on changes in electric field strength) can operate in a similar mode; see U.S. Patent 4,418,346.

[0016] An encapsulated or microcellular electrophoretic display typically does not suffer from the clustering and settling failure modes of conventional electrophoresis devices and offers additional advantages, such as the ability to print or coat the display on a variety of flexible and rigid substrates. (The use of the word "printing" is intended to encompass all forms of printing and coating, including but not limited to: pre-metered coatings (e.g., patch die coating, slot or extrusion coating, slide or cascade coating, and curtain coating); roll coating (e.g., knife over roll coating and forward and reverse roll coating); gravel coating; dip coating; spray coating; meniscus coating; spin coating; brush coating; air knife coating; silk screen printing processes; electrostatic printing processes; thermal printing processes; and inkjet printing processes.) Processes); electrophoretic deposition; and other similar techniques. Therefore, the resulting display can be flexible. Furthermore, because the display medium can be printed (using various methods), the display itself can be manufactured inexpensively.

[0017] An electro-optic display typically includes an electro-optic material and at least two other layers disposed on opposite sides of the electro-optic material, one of which is an electrode layer. In most such displays, both layers are electrode layers, and one or both of these electrode layers are patterned to define pixels of the display. In most electro-optic displays, at least one of these electrode layers is light-transmitting. In passive matrix devices, one electrode layer may be patterned as a plurality of elongated column electrodes, while the other electrode layer is patterned as a plurality of elongated row electrodes extending perpendicularly to the column electrodes, with pixels defined by the intersections of the column and row electrodes. Alternatively, more commonly, one electrode layer has the form of a single continuous (light-transmitting) electrode, while the other electrode layer is patterned as a matrix of pixel electrodes, each pixel electrode defining a pixel of the display. In another type of electrophoretic display used with a stylus, printhead, or similar movable electrode intended to be separate from the display, only the layer adjacent to the electro-optic layer contains electrodes, and the layer on the opposite side of the electro-optic layer is typically a protective layer intended to prevent damage to the electro-optic layer by the movable electrode.

[0018] The fabrication of three-layer electro-optic displays typically involves at least one lamination operation. For example, the aforementioned MIT and E Ink patents and applications describe a method for manufacturing an encapsulated electrophoretic display, wherein an encapsulated electrophoretic medium containing capsules in an adhesive is coated onto a flexible substrate, the flexible substrate comprising an indium tin oxide (ITO) or similar conductive coating (which acts as an electrode of the final display) on a plastic film (e.g., polyethylene terephthalate (PET)). The capsule / adhesive coating is then dried to form an adhesive layer firmly bonded to the electrophoretic medium on the substrate. Separately, a backplane is prepared, comprising a pixel electrode array and conductors suitably configured to connect the pixel electrodes to driving circuitry. To form the final display, a substrate having the capsule / adhesive layer is laminated onto the backplane using a lamination adhesive. (By replacing the backplane with a simple protective layer (e.g., a plastic film), a very similar method can be used to fabricate electrophoretic displays that can be used with a stylus or similar movable electrodes on which the stylus or its movable electrodes can slide.) In one form of such a method, the backplane itself is flexible and is fabricated by printing pixel electrodes and conductors onto a plastic film or other flexible substrate. The lamination technique used to mass-produce displays using this method involves roll-to-roll lamination using a lamination adhesive. Similar manufacturing techniques can be used for other types of electro-optic displays. For example, microcellular electrophoretic media or rotating dual-color component media can be laminated onto the backplane in a manner substantially similar to that used for encapsulated electrophoretic media.

[0019] As discussed in U.S. Patent No. 6,982,178, many components used in solid-state electrophoretic displays and the methods for manufacturing such displays are derived from the technology used in liquid crystal displays (LCDs), which are also electro-optic displays but use a liquid medium. However, the methods used to assemble LCDs cannot be used for solid-state electro-optic displays. LCD assembly typically involves forming a backplate and front electrode on separate glass substrates, then bonding these components together, leaving a small hole between them; placing the resulting assembly in a vacuum; and immersing the assembly in a liquid crystal bath, allowing liquid crystal to flow through the hole between the backplate and the front electrode. Finally, after the liquid crystal is in place, the hole is sealed to provide the final display.

[0020] Segmented electro-optic displays include an arrangement of display segment electrodes that can be individually controlled to display a desired image. In conventional segmented electro-optic displays, the display segment electrodes are formed in the backplane of the display and are selectively driven to change the optical state of adjacent portions of the electro-optic medium. The display segment electrodes are patterned on a substrate in the backplane and then laminated to a front planar laminate containing the electro-optic medium using an adhesive. The thickness of the substrate plus the thickness of the front planar laminate adhesive increases the overall volume and rigidity of the structure, reducing the flexibility of the device. A segmented electro-optic device with improved flexibility and a method for manufacturing the same are needed. Summary of the Invention

[0021] In one embodiment of the invention, a flexible segmented electrophoretic display includes an electroactive layer having a front viewing side and an opposing rear side. The electroactive layer includes an encapsulated electrophoretic medium. A transparent common electrode layer is superimposed on the front viewing side of the electroactive layer. A plurality of display segment electrodes are directly adjacent to the rear side of the electroactive layer. Each of the display segment electrodes is associated with an adjacent portion of the encapsulated electrophoretic medium. A processor die is electrically connected to each of the plurality of display segment electrodes to apply a voltage to a selected display segment electrode, thereby driving the respective associated portions of the encapsulated electrophoretic medium between different optical states. A protective seal encapsulates at least the electroactive layer, the transparent common electrode layer, the plurality of display segment electrodes, and the processor die.

[0022] A method for constructing a flexible segmented electrophoretic display according to one embodiment of the present invention includes the following steps: (a) forming an electroactive layer comprising an encapsulated electrophoretic medium on one side of a transparent common electrode layer; (b) applying a viewing-side protective sealing layer on the other side of the transparent common electrode layer; (c) printing a plurality of display segment electrodes directly adjacent to one side of the electroactive layer opposite to the transparent common electrode layer, wherein each of the display segment electrodes is associated with an adjacent portion of the encapsulated electrophoretic medium; and (d) bonding a processor die to the plurality of display segments. (e) Printing interconnects near the segment electrodes to electrically connect the processor die to each of the plurality of display segment electrodes, such that the processor die can selectively apply voltage to the display segment electrodes to drive the respective portions of the encapsulated electrophoretic medium between different optical states; and (f) applying a back protective sealing layer above the processor die and the interconnects, such that the back protective sealing layer and the viewing-side protective sealing layer encapsulate the electroactive layer, the light-transmitting common electrode layer, the plurality of display segment electrodes, the interconnects, and the processor die.

[0023] According to another aspect of the present invention, a method for constructing a flexible segmented electrophoretic display includes the following steps: (a) forming an electroactive layer comprising an encapsulated electrophoretic medium on one side of a conductive integrated barrier layer; (b) printing a plurality of display segment electrodes directly adjacent to one side of the electroactive layer opposite to the conductive integrated barrier layer, wherein each of the display segment electrodes is associated with an adjacent portion of the encapsulated electrophoretic medium; (c) bonding a processor die to the vicinity of the plurality of display segment electrodes; (e) printing interconnects such that the processor die is electrically connected to each of the plurality of display segment electrodes, such that the processor die can selectively apply voltage to the display segment electrodes to drive respective associated portions of the encapsulated electrophoretic medium between different optical states; and (d) applying a back protective sealing layer above the processor die and the interconnects, such that the back protective sealing layer and the integrated barrier layer encapsulate the electroactive layer, the plurality of display segment electrodes, the interconnects, and the processor die.

[0024] According to one or more embodiments, the encapsulated electrophoretic medium includes an electrophoretic medium encapsulated within microcapsules dispersed in a polymer binder or contained in sealed microcells.

[0025] According to one or more embodiments, the processor die has a thickness of less than 100 μm (preferably, less than 50 μm).

[0026] According to one or more embodiments, there is no air gap between the processor die and the protective seal.

[0027] According to one or more embodiments, the processor die is fixed to the electrophoretic display via a flip-chip bonding process.

[0028] According to one or more embodiments, the protective seal includes a low water vapor penetration rate (WVTR) edge sealing resin.

[0029] According to one or more embodiments, the processor die is mounted on a flexible carrier film that provides fan-out wiring for the processor die to facilitate electrical connection to the display segment electrodes.

[0030] According to one or more embodiments, the processor die is electrically connected to each of the plurality of display segment electrodes via interconnects including printed conductive ink.

[0031] According to one or more embodiments, these interconnects are printed using a pulse printing process.

[0032] According to one or more embodiments, the display further includes additional interconnects that electrically connect the processor die to power and control input contacts at one edge of the protective seal.

[0033] According to one or more embodiments, these additional interconnects include conductive carbon, silver, or copper.

[0034] According to one or more embodiments, these power and control input contacts include power, ground, data, and clock input terminals.

[0035] According to one or more embodiments, the protective seal includes a rear protective seal facing the rear side of the electroactive layer and a front protective seal facing the front viewing side of the electroactive layer.

[0036] According to one or more embodiments, the front protective seal and the rear protective seal form a barrier edge seal to prevent the entry of moisture or contaminants.

[0037] According to one or more embodiments, the barrier edge seal includes a compression edge seal.

[0038] According to one or more embodiments, the plurality of display segment electrodes are directly printed on the electroactive layer using an inkjet or screen printing process.

[0039] According to one or more embodiments, the display further includes a color filter array located between the electroactive layer and the light-transmitting common electrode layer.

[0040] According to one or more embodiments, the display segment electrodes comprise conductive carbon.

[0041] According to one or more embodiments, the display further includes a dielectric layer selectively formed over the display segment electrodes, and wherein the processor die is bonded to the dielectric layer.

[0042] According to one or more embodiments, the display further includes an encapsulation material located between the protective seal and the processor die or the interconnects.

[0043] According to one or more embodiments, the plurality of display segment electrodes are directly behind the electroactive layer, without any adhesive layer in between.

[0044] According to one or more embodiments, the plurality of display segment electrodes are directly behind the electroactive layer, with no substrate in between. Simple Explanation of the Diagram

[0045] Additional details of one or more embodiments of the subject matter described herein are set forth in the accompanying drawings and the following description. Other features, features, and advantages of the subject matter will become apparent from the description and drawings contained herein. It should be emphasized that the drawings are schematic and not drawn to scale. Specifically, for ease of illustration, the thickness of each layer in the drawings does not correspond to its actual thickness. Furthermore, the thickness of each layer is not proportional to its lateral dimension. Generally, throughout the drawings, elements with similar structures are annotated with similar element symbols for illustrative purposes. However, the specific properties and functions of elements in different embodiments may differ. Moreover, the drawings are intended only to facilitate the description of the subject matter. The drawings do not illustrate every feature of the described embodiments and do not limit the scope of this disclosure or the claims. Figure 1 is a schematic diagram showing an exemplary conventional segmented electro-optical device; Figure 2 is a schematic cross-sectional view showing an exemplary front flat surface layer of a conventional segmented electro-optic device; Figures 3A and 3B are schematic cross-sectional and plan views, respectively, illustrating an exemplary flexible segmented electrophoresis display with a distributing edge seal according to one or more embodiments; Figure 4 is a schematic cross-sectional view illustrating an exemplary flexible segmented electrophoresis display with a press-fit edge seal according to one or more other embodiments; Figure 5 is a schematic cross-sectional view illustrating an exemplary flexible segmented electrophoresis display with an integrated front barrier layer and a distribution edge seal, according to one or more other embodiments. Implementation

[0046] The various embodiments disclosed herein relate to a flexible segmented electrophoretic display having a plurality of display segment electrodes directly adjacent to one side of the electroactive layer of the device, rather than in a backing plate laminated to the electroactive layer. Such a display provides improved flexibility and other advantages discussed below.

[0047] Figure 1 schematically illustrates a segmented electro-optic device 114 of the prior art, which includes a backplate 112 laminated to a front planar area layer 100. The front planar area layer 100 includes an encapsulated electrophoretic or other electro-optic medium 106 as shown in Figure 2. The backplate 112 includes a rigid or flexible layer on which a plurality of display segment electrodes (e.g., carbon electrodes on a PET layer or copper electrodes on a polyimide layer or an FR-4 glass-reinforced epoxy laminate) are deposited. Each display segment electrode is associated with an adjacent portion of the encapsulated electro-optic medium, such that a voltage selectively applied to the display segment electrode drives individual associated portions of the encapsulated electrophoretic medium to switch between different optical states.

[0048] The back panel 112 may include electronics for addressing the display, or such electronics may be housed in a unit separate from the back panel. The back panel has barrier properties to prevent moisture and other contaminants from entering, particularly via the non-viewing side of the display. (Of course, the display is typically viewed from the side furthest from the back panel.)

[0049] The front flat panel 100 shown in Figure 2 is also described in U.S. Patent No. 10,503,041. The front flat panel 100 sequentially includes a front planar light-transmitting substrate 102, a light-transmitting conductive layer 104 in contact with the inner surface of the front planar light-transmitting substrate 102, an electro-optic dielectric layer (i.e., an electroactive layer) 106, an adhesive layer 108, and a release sheet 110.

[0050] The front-plane light-transmitting substrate 102 may include a PET layer, while the light-transmitting conductive layer 104 may include an ITO layer. Such materials are commercially available, for example, from Saint-Gobain in bulk rolls. The light-transmitting conductive layer 104 is applied to the light-transmitting substrate 102, which is typically flexible; in this sense, the substrate can be manually wound onto a roller with a diameter of, for example, 10 inches (254 mm) without permanent deformation.

[0051] As used herein, the term "transmittance" is consistent with its conventional meaning in the art of electro-optic displays and in the aforementioned patents and publications, indicating that the specified layer transmits sufficient light to allow a viewer to see through it to observe changes in the display state of the electro-optic medium, typically through the conductive layer 104 and the adjacent substrate 102. In the case where the electro-optic medium 106 displays changes in reflectivity at invisible wavelengths, the term "transmittance" should of course be interpreted as referring to the transmission of the relevant invisible wavelengths. The substrate 102 may be made of glass or a polymer film (e.g., PET) and may have a thickness ranging from about 20 μm to about 650 μm, more typically from about 50 μm to about 250 μm. The conductive layer 104 is typically a thin layer of so-called "transparent conductive oxide," such as aluminum oxide, zinc oxide, indium zinc oxide, or indium tin oxide, or the conductive layer 104 may comprise a conductive polymer, such as poly(3,4-ethylenedioxythiophene) (PEDOT). The design may also include hybrid materials, such as a combination of conductive polymers and conductive oxides, or it may include diluted amounts of conductive fillers (e.g., silver whiskers or silver flakes) or dissimilar materials (e.g., nanotubes and graphene). In some embodiments, the substrate 102 may be a rigid, light-transmitting material, such as glass or transparent polycarbonate or acrylic.

[0052] Typically, a coating of electro-optic medium 106, which can switch between optical states, is applied to the conductive layer 104, such that the electro-optic medium 106 is adjacent to the conductive layer 104. The electro-optic medium 106 is typically characterized by an electrophoretic material comprising a plurality of charged particles disposed in a fluid and capable of moving through the fluid under the influence of an electric field. The electrophoretic material can be selected such that, when an appropriate electric field is applied, the front planar surface plate can interchangeably and reversibly achieve different states; for example, the electrophoretic medium can switch between transparent and opaque, or between color 1 and color 2, or between transparent and color 1 and color 2.

[0053] The electro-optic medium 106 can be in the form of a two-particle encapsulated medium with opposite charges. Such an encapsulated medium comprises a plurality of small capsules, each capsule comprising an inner phase containing electrophoretically moving particles suspended in a liquid suspension medium and a capsule wall surrounding the inner phase. Typically, the capsules themselves are fixed within a polymer binder to form an adhesive layer. When the adhesive layer is positioned between two electrodes, the optical state can be reversed in the presence of a suitable electric field. The suspension medium may comprise a hydrocarbon-based liquid in which negatively charged white particles and positively charged black particles are suspended. When an electric field is applied to the electro-optic medium, the white particles move to the positive electrode, while the black particles move to the negative electrode, for example, causing the electro-optic medium 106 to appear white or black to a viewer viewing the display through the substrate 102, depending on whether the conductive layer 104 is positive or negative relative to the backplane at any location within the final display. In addition to black and / or white particles, the electro-optic medium 106 may also comprise a plurality of colored particles, each color having an individual charge polarity and intensity. Although not shown in the figure, the above-mentioned type of microcellular medium can also be used as an electro-optic medium 106.

[0054] A laminated adhesive layer 108 is coated on the electro-optic dielectric layer 106, and a release sheet 110 is applied to the adhesive layer 108. The release sheet 110 can be of any known type, provided it does not contain materials that adversely affect the properties of the electro-optic dielectric. Many suitable types of release sheets are known to those skilled in the art. Common release sheets include substrates such as paper or plastic films (e.g., PET films with a thickness of about 150 μm to about 200 μm coated with a low surface energy material (e.g., polysiloxane)). In some cases, the release sheet is metallized to allow a potential to be applied to the electro-optic dielectric so that functionality can be evaluated during the assembly of downstream products.

[0055] The electro-optic display 114 of FIG. 1 is assembled by removing the release tab 110 from the front planar laminate 100 and bringing the adhesive layer 108 into contact with the back plate 112 while effectively adhering the adhesive layer 108 to the back plate 112, thereby fixing the adhesive layer 108, the electro-optic dielectric layer 106, and the light-transmitting conductive layer 104 to the back plate 112. The front planar laminate 100 can be cut to a size larger than the final display size and can even be a continuous sheet in a roll-to-roll process. This allows for coarse tolerances in the alignment of the front planar laminate 100 and the back plate 112, which is particularly helpful for large displays. Once laminated, the display can be cut to its final size, possibly using alignment marks or locating pins on the back plate to allow for precise alignment of the cut with the back plate.

[0056] Segmented display devices include driver chips or integrated circuits (ICs) for selectively applying voltages to display segment electrodes to drive the respective portions of the encapsulated electrophoretic dielectric to switch between different optical states. The driver chip or IC is typically connected to a backplane substrate via a tail folded behind the electroactive region.

[0057] Segmented display devices include barrier edge seals to prevent moisture and other contaminants from entering from the outer edge of the display. Compression seals and distribution seals are two commonly used types of edge seals in electrophoretic displays. Compression edge seals are less expensive and are typically used in segmented displays, where the backplane substrate extends to the outer edge of the seal. Compression edge seals reduce the air gap size at the edge of the front planar laminate. However, the substrate is generally more permeable than the barrier layer, thus requiring a wider edge seal.

[0058] The conventional technique of using adhesive to laminate patterned display segment electrodes onto a backplate substrate of a front flat laminate results in a segmented electrophoretic display with significantly reduced flexibility due to the increased volume of the structure caused by the adhesive between the backplate substrate and the laminate.

[0059] Furthermore, to provide a flexural neutral axis for the electrophoretic medium near the front electrode, additional compensation layers may need to be added to the front viewing side of the device. This adds further rigidity and may require compromises with other front-side requirements, such as protective sealing. As a result, conventional devices typically have multiple delicate barrier and conductor layers separated by other layers within the display stack, thus requiring careful mechanical design and a larger minimum bending radius.

[0060] Another drawback of conventional segmented displays is related to the backplane manufacturing process. Screen printing of electrodes is typically used for low-cost backplanes and is cost-effective at high production volumes, but the setup cost and lead time are unsuitable for small-batch prototypes. Rigid printed etched copper circuitry is more expensive and may be difficult to use with the thin adhesive layers required for displays.

[0061] These and other drawbacks of conventional techniques can be overcome by a flexible segmented electrophoretic display in which the display segment electrodes are directly printed adjacent to the electroactive layer. This eliminates the need for a backplane substrate and adhesives between the electroactive layer and the display segment electrodes, thereby reducing the thickness of the device and increasing its flexibility.

[0062] Figures 3A and 3B schematically illustrate an exemplary flexible segmented electrophoretic display 200 according to one or more embodiments. Figure 3A is a cross-sectional view of device 200, while Figure 3B is a plan view of selected components of device 200. Display 200 includes an electroactive layer 106 containing encapsulated electrophoretic media, similar to the electroactive layers discussed previously. Electroactive layer 106 may include a plurality of microcells filled with electrophoretic fluid and sealed by a sealing layer. Electroactive layer 106 may alternatively include a plurality of microcapsules containing electrophoretic fluid and dispersed in a polymer binder.

[0063] A transparent common electrode layer 202 is superimposed on the front viewing side of the electroactive layer. For example, the transparent common electrode layer 202 includes a flexible substrate 204 (e.g., a plastic film such as PET) having an ITO or other similar conductive coating 206, wherein the ITO or other similar conductive coating 206 serves as the top common electrode of the display 200.

[0064] A plurality of display segment electrodes 208 (i.e., pixel electrodes) are formed on opposite rear sides of the electroactive layer 106. The plurality of display segment electrodes 208 are directly adjacent to the rear side of the electroactive layer 106 without any substrate or adhesive layer between them to reduce structural volume and increase flexibility. Each display segment electrode 208 is associated with an adjacent portion of the encapsulated electrophoretic medium.

[0065] In one or more embodiments, the display segment electrode 208 is directly printed onto the electroactive layer 106 using an inkjet or screen printing process. The display segment electrode 208 may comprise various conductive materials, including conductive carbon.

[0066] Various low-curing or drying temperature inks and rapid curing or drying processes (e.g., using photonic sintering) can be used to directly and safely print display segment electrodes 208 onto the electroactive layer 106.

[0067] A processor or driver die 210 is electrically connected to each of a plurality of display segment electrodes 208 to apply a voltage to the selected display segment electrode 208, thereby driving various relevant portions of the encapsulated electrophoretic medium between different optical states. The processor die 210 is connected to each display segment electrode 208 via interconnects 212. In one or more embodiments, the interconnects 212 comprise printed conductive ink. In one or more embodiments, the interconnects 212 comprise conductive carbon, silver, or copper. In one or more embodiments, the interconnects 212 are printed using a high-resolution printing process (e.g., aerosol inkjet or pulse printing).

[0068] Protective seals encapsulate components of the device to prevent or prohibit the ingress of moisture or contaminants. In the embodiment of FIG. 3A, the protective seals include a rear protective seal 214 facing the rear side of the electroactive layer 106 and a front protective seal 216 facing the opposite front viewing side of the electroactive layer 106. An edge protective seal 218 covers the periphery of the device 200 extending between the front protective seal 216 and the rear protective seal 214. In one or more embodiments, the protective seals comprise a low water vapor penetration rate (WVTR) edge sealing resin.

[0069] The display 200 further includes interconnects 219 for electrically connecting the processor die 210 to power and control input contacts 220 at the edge of the protective seal. The interconnects 219 may include conductive carbon, silver, or copper. In one or more embodiments, the power and control input contacts 220 include power, ground, data, and clock inputs.

[0070] The dielectric layer 222 is printed in a multilayer manner, which is inclined around the processor die 210, thereby electrically insulating the processor die 210 from the display segment electrode 208.

[0071] The display 200 further includes encapsulation material 224 located between the protective seal and the processor die 210 and interconnects 212, 219. The encapsulation material 224 protects the components of the device 200, particularly the printed circuit layers. Furthermore, the encapsulation material 224 also acts as a pressure-sensitive adhesive for protecting the seal 214 after lamination.

[0072] In one or more embodiments, the processor die 210 is mounted on a flexible carrier film, wherein the flexible carrier film provides fan-out wiring for the processor die 210 to facilitate electrical connection with the display segment electrode 208.

[0073] In one or more embodiments, the display 200 further includes a color filter array (CFA) or other graphic overlay 226 located between the electroactive layer 106 and the transparent common electrode layer 202. The CFA 226 contains an array of color filters that can be placed on the monochrome electroactive layer 106 to display a color image.

[0074] The processor die 210, used to drive the electroactive layer 106, is connected to and very close to the display segment electrode 208. Placing the processor die 210 within a protective seal eliminates the need for connectors to connect the display segment electrode 208 to an external processor. This allows for a higher number of display segment electrodes 208, as conventional displays with many display segment electrodes would require high pin count connectors. However, high pin count connectors can be too wide for many applications. For example, the spacing of such connectors is typically 0.5 mm or wider. Therefore, a 100-pin connector could have an excessive width of at least 50 mm. Furthermore, such connectors are expensive and could be a potential source of reliability issues.

[0075] In one or more embodiments, the processor die 210 includes a thin die with a thickness of less than 100 μm (preferably less than 50 μm). For example, the die 210 may have a thickness of about 40 μm. The thin processor die 210 makes it possible to laminate the rear protective seal 214 onto the die 210 without a substantial air gap around the die 210. Alternatively, a thicker die 210 can be attached to the display segment electrode 208 using a standard flip-chip bonding process and encapsulated with a low WVTR edge sealing resin. Standard anisotropic adhesives can be used for flip-chip bonding. The thin or thick processor die 210 can also be attached to a flexible carrier film, wherein the flexible carrier film provides fan-out from fine-pitch die wiring to print-compatible coarse-pitch wiring.

[0076] The flexible segmented electrophoretic display 200 with distribution edge seal 218 shown in Figures 3A and 3B can be constructed using the following exemplary processes according to one or more embodiments: 1. If the device 200 is to include an optional CFA or other patterned overlay 226, the CFA or patterned overlay 226 is printed on the conductive side of the transparent common electrode layer 202 (e.g., on the ITO side of the PET / ITO layer 202); 2. An electroactive layer 106 containing an encapsulated electrophoretic medium is formed on a CFA or patterned capping layer 226 on a transparent common electrode layer 202. If the electroactive layer 106 includes electrophoretic microcapsules, the CFA or patterned capping layer 226 is coated with a slurry containing microcapsules and a polymer binder. If the electroactive layer 106 includes a sealed array of microcells containing electrophoretic fluid, the electroactive layer 106 is formed by (i) imprinting microcells onto a polymer film deposited on the CFA or patterned capping layer; (ii) filling the microcells with electrophoretic fluid; and (iii) sealing the microcells with a polymer sealing layer. 3. Apply the front-viewing protective sealing layer 216 to the front side of the light-transmitting common electrode layer 202 opposite to the CFA or graphic overlay layer 226. This can be done as follows: (a) Apply or laminate the protective sealant 215 to the front side of the light-transmitting common electrode layer 202; (b) The laminate, comprising the electroactive layer 106, the light-transmitting common electrode layer 202, and the protective sealing adhesive layer 215, is cut to a size designed to fit the required active area; (c) Clean the top plane wiring (TPC); (d) Laminate the front-viewing side protective seal 216 onto the protective seal adhesive 215; 4. Using, for example, conductive carbon ink, the display segment electrode 208 is printed directly adjacent to the side of the electroactive layer 106 opposite to the light-transmitting common electrode layer 202. Prior to this step, a primer layer may optionally be applied to the electroactive layer 106 to improve printing resolution by controlling surface energy, polarity, and roughness; 5. With the die bumps facing upwards (i.e., the die bumps 230 are located on the side of the die 210 opposite to the display segment electrode 208), the processor die 210 is bonded to the vicinity of the plurality of display segment electrodes 208; 6. The dielectric layer 222 is printed in a multilayer manner, sloped upwards around the processor die 210; 7. Print interconnects 212 using a conductive material (e.g., conductive carbon, silver, or copper ink) to electrically connect the processor die bumps 230 to each display segment electrode 208; 8. Deposit packaging material 224 over the processor die 210 and interconnects 212 to protect the printed circuit layer and act as a pressure-sensitive adhesive for protecting the seal 214 after lamination; 9. Apply a post-protective sealing layer 214 over the encapsulation material 224; 10. Apply edge sealant 218 around the periphery of the viewing-side protective seal and the rear protective seal using a standard dispensing process; 11. If the initial size of the front protective seal 216 is too large, adjust it to the final size for ease of operation.

[0077] Figure 4 is a schematic cross-sectional view of an exemplary flexible segmented electrophoresis display 250 according to one or more other embodiments. The display 250 includes a compression edge seal, instead of the side seal 218 of the display 200 shown in Figures 3A and 3B.

[0078] The display 250 of Figure 4 can be constructed using the following exemplary processes according to one or more embodiments: 1. If the device 250 is to include an optional CFA or other graphic overlay 226, the CFA or graphic overlay 226 is printed on the conductive side of the transparent common electrode layer 202 (e.g., on the ITO side of the PET / ITO layer 202); 2. An electroactive layer 106 containing an encapsulated electrophoretic medium is formed on a CFA or patterned cover layer 226 on a transparent common electrode layer 202. If the electroactive layer 106 includes electrophoretic microcapsules, the CFA or patterned cover layer 226 is coated with a slurry containing microcapsules and a polymer binder. If the electroactive layer 106 includes a sealed array of microcells containing electrophoretic fluid, the electroactive layer 106 is formed by (i) imprinting microcells on a polymer film; (ii) filling the microcells with electrophoretic fluid; and (iii) sealing the microcells with a polymer sealing layer. 3. Apply the front-viewing protective sealing layer 216 to the front side of the light-transmitting common electrode layer 202 opposite to the CFA or graphic overlay layer 226. This can be done as follows: (a) Apply or laminate the protective sealant 215 to the front side of the light-transmitting common electrode layer 202; (b) Clean the top plane wiring (TPC); (c) Lamination of the front-viewing side protective seal 216 onto the protective seal adhesive 215; 4. Using, for example, conductive carbon ink, the display segment electrode 208 is printed directly adjacent to the side of the electroactive layer 106 opposite to the light-transmitting common electrode layer 202. Prior to this step, a primer layer may optionally be applied to the electroactive layer 106 to improve printing resolution by controlling surface energy, polarity, and roughness; 5. The first dielectric layer 252 is printed in a multilayer manner, sloped around the laminate including the CFA cover layer 226, the electroactive layer 106, the display segment electrode 208 and the light-transmitting common electrode layer 202. 6. With the die bumps facing upwards (i.e., the die bumps 230 are located on the side of the die 210 opposite to the display segment electrode 208), the processor die 210 is bonded to the vicinity of the plurality of display segment electrodes 208; 7. The second dielectric layer 222 is printed in a multilayer manner, sloped upwards around the processor die 210; 8. Print interconnects 212 using a conductive material (e.g., conductive carbon, silver, or copper ink) to electrically connect the processor die bumps 230 to each display segment electrode 208; 9. Deposit packaging material 224 over the processor die 210 and interconnects 212 to protect the printed circuit layer and act as a pressure-sensitive adhesive for protecting the seal 214 after lamination; 10. Apply a rear protective seal layer 214 over the encapsulation material 224; 11. If the initial size of the front protective seal 216 is too large, adjust it to the final size for ease of operation.

[0079] Figure 5 is a schematic cross-sectional view illustrating an exemplary flexible segmented electrophoretic display 280 according to one or more other embodiments. Instead of having a front protective seal 216 as shown in Figures 3A and 4, device 280 includes a barrier layer 282 integrated into the light-transmitting common electrode layer 202 (e.g., between the ITO layer 206 and the PET layer 204). The integrated front barrier layer reduces the overall film stack thickness. Device 280 shown in Figure 5 also includes distributed edge seals 218, similar to the edge seals 218 of the device shown in Figure 3A. Although not shown, similar devices with integrated front barrier layers and compression edge seals similar to those shown in Figure 4 can be constructed.

[0080] The display 280 of Figure 5 can be constructed using the following exemplary processes according to one or more embodiments: 1. An electroactive layer 106 comprising an encapsulated electrophoretic medium is deposited on a release membrane. If the electroactive layer 106 comprises electrophoretic microcapsules, the release membrane is coated with a slurry containing microcapsules and a polymer binder. If the electroactive layer 106 comprises a sealed array of microcells containing electrophoretic fluid, the electroactive layer 106 is formed by (i) imprinting microcells onto a polymer membrane deposited on the release membrane; (ii) filling the microcells with electrophoretic fluid; and (iii) sealing the microcells with a polymer sealing layer. 2. Laminate the air-side laminate (ASL) adhesive 284 onto one side of the electroactive layer 106 opposite the release film; 3. Cut the electroactive layer 106, which contains the release film and ASL adhesive, to fit the desired active area; 4. Remove the release film from the electroactive layer 106 and laminate the electroactive layer 106 to one side of the conductive integrated barrier layer using ASL adhesive 284; 5. Clean the top-plane wiring (TPC); 6. Using, for example, conductive carbon ink, the display segment electrode 208 is printed directly adjacent to the side of the electroactive layer 106 opposite to the conductive integrated barrier layer 282. Prior to this step, a primer layer may optionally be applied to the electroactive layer 106 to improve printing resolution by controlling surface energy, polarity, and roughness; 7. With the die bumps facing upwards (i.e., the die bumps 230 are located on the side of the die 210 opposite to the display segment electrode 208), the processor die 210 is bonded to the vicinity of the plurality of display segment electrodes 208; 8. The dielectric layer 222 is printed in a multilayer manner, sloped upwards around the processor die 210; 9. Print interconnects 212 using a conductive material (e.g., conductive carbon, silver, or copper ink) to electrically connect the processor die bumps 230 to each display segment electrode 208; 10. Deposit encapsulation material 224 over the processor die 210 and interconnects 212 to protect the printed circuit layer and act as a pressure-sensitive adhesive for protecting the seal 214 after lamination; 11. Apply a post-protective sealing layer 214 over the encapsulation material 224; 12. Apply edge seals 218 around the conductive integrated barrier layer and the back protective seal layer using a standard dispensing process.

[0081] As described above, the flexible segmented electro-optic display according to various embodiments includes display segment electrodes 208 directly printed adjacent to one side of the electroactive layer 106. A significant advantage of this structure is the elimination of any lamination adhesives or substrates between the display segment electrodes 208 and the electroactive layer 106. In some embodiments, all adhesives around the electroactive layer 106 are eliminated. This reduces the overall thickness of the device, which helps to minimize the elongation and compression of the fine conductors and barrier coatings when the device is bent. This, in turn, makes the overall mechanical design of the device stack more tolerant.

[0082] Flexible segmented electro-optic displays according to various embodiments may also have a large number of display segments while using small connectors, for example, connectors with only two wires (see, for example, U.S. Patent No. 6,459,363 which describes how to use two wires for data and power transmission) or more typically four wires (PWR, GND, DATA, CLK), instead of the typical configuration where each display segment 208 has a wire connection.

[0083] Another advantage of the flexible segmented electrophoretic displays according to various embodiments is that they can be manufactured without precise layer alignment. This can be a significant advantage, especially during the early prototyping stages of a project. Precise alignment of printing steps can be achieved using optical references and pattern recognition commonly used in research and production-grade printers.

[0084] Another advantage of the methods for manufacturing flexible segmented electrophoretic displays according to the various embodiments is that they are tooling-free. This greatly reduces upfront investment in mechanical design and engineering time, especially in the early prototyping stages of a project.

[0085] Another advantage of the method disclosed in this paper is that the printing processes used in the production of displays include additive manufacturing processes, thereby minimizing material waste. For example, further reductions in material waste can be achieved by printing the adhesive directly onto the surface instead of using an adhesive pre-coated on a release film.

[0086] For those skilled in the art, it will be apparent that many changes and modifications can be made to the specific embodiments of the present invention described above without departing from the scope of the invention. Therefore, the entire description above should be interpreted in an illustrative rather than restrictive sense.

[0087] 100: Front flat area shelf 102: Front-plane transparent substrate 104: Transparent Conductive Layer 106: Electro-optic dielectric 108: Adhesive layer 110: Release film 112 backplate 114: Segmented Electro-optical Device 200: Monitor 202: Transparent Common Electrode Layer 204: Flexible substrate 206: ITO or other similar conductive coating 208: Display segment electrode 210: Processor or driver die 212: Internal connection 214: Rear protective seal 215: Protective sealant adhesive 216: Front protective seal 218: Edge protection seal 219: Internal Connection 220: Power and control input contacts 222: Dielectric layer (second dielectric layer) 224: Packaging Material 226: Color Filter Array (CFA) or other graphic overlay 230: Grain bumps 250: Flexible segmented electrophoresis display 252: First dielectric layer 280: Flexible segmented electrophoresis display 282: Barrier Layer 284: Air-side laminate (ASL) adhesive

Claims

1. A method for constructing a flexible segmented electrophoretic display, comprising the steps of: (a) forming an electroactive layer comprising an encapsulated electrophoretic medium on one side of a transparent common electrode layer; (b) applying a viewing-side protective sealing layer on the other side of the transparent common electrode layer; (c) depositing a plurality of display segment electrodes directly adjacent to one side of the electroactive layer opposite to the transparent common electrode layer, wherein each of the display segment electrodes is associated with an adjacent portion of the encapsulated electrophoretic medium; and (d) bonding a processor die to the vicinity of the plurality of display segment electrodes. (e) Depositing interconnects to electrically connect the processor die to each of the plurality of display segment electrodes, such that the processor die can selectively apply voltage to the display segment electrodes to drive the respective portions of the encapsulated electrophoretic medium between different optical states; and (f) Applying a back protective sealing layer above the processor die and the interconnects, such that the back protective sealing layer and the viewing-side protective sealing layer encapsulate the electroactive layer, the light-transmitting common electrode layer, the plurality of display segment electrodes, the interconnects, and the processor die.

2. The method of claim 1, wherein the electroactive layer comprises an array of microcells filled with an electrophoretic fluid and sealed by a sealing layer.

3. The method of claim 1, wherein forming the electroactive layer comprises: (i) Imprinting microcells onto a polymer film; (ii) Fill the microcells with an electrophoretic fluid; (iii) Seal the microcells with a polymer sealing layer.

4. The method of claim 1, wherein the electroactive layer comprises a plurality of microcapsules dispersed in a polymer binder, the microcapsules containing an electrophoretic fluid.

5. The method of claim 1, further comprising encapsulating an electrophoretic medium in microcapsules and dispersing the microcapsules in a binder to form a slurry, wherein step (a) comprises coating the transparent common electrode layer with the slurry.

6. The method of claim 1, further comprising forming a color filter array on one side of the light-transmitting common electrode layer prior to step (a).

7. The method of claim 1 further includes depositing a dielectric layer around the processor die.

8. The method of claim 1 further includes depositing a dielectric layer over the selected portion of the display segment electrodes prior to step (d).

9. The method of claim 1 further includes, prior to step (f), depositing a packaging material above the processor die and the interconnects.

10. The method of claim 1 further includes forming an edge seal around the periphery of the viewing-side protective seal and the rear protective seal to prevent the ingress of moisture or contaminants.

11. The method of claim 10, wherein forming the edge seal includes applying a seal around the periphery of the display, the seal extending between the viewing-side protective seal and the rear protective seal.

12. The method of claim 10, wherein forming the edge seal includes pressing the viewing-side protective seal layer together with the peripheral edge of the rear protective seal layer.

13. The method of claim 1, wherein step (d) includes bonding the processor die to the electrophoretic display using a flip-chip bonding process.

14. The method of claim 1, wherein step (e) includes depositing the interconnects using a pulse printing process.

15. The method of claim 1, wherein step (c) includes printing the plurality of display segment electrodes using an inkjet or screen printing process.

16. The method of claim 1, wherein the plurality of display segment electrodes are deposited directly on the back side of the electroactive layer, with no substrate in between.

17. The method of claim 1, wherein the plurality of display segment electrodes are deposited directly on the back side of the electroactive layer without any adhesive in between.

18. A flexible segmented electrophoretic display constructed according to any one of claims 1-17.

19. A method of constructing a flexible segmented electrophoretic display, comprising the steps of: (a) forming an electroactive layer including an encapsulated electrophoretic medium on one side of a conductive integrated barrier layer; (b) depositing a plurality of display segment electrodes directly adjacent to one side of the electroactive layer opposite the conductive integrated barrier layer, wherein each of the display segment electrodes is associated with an adjacent portion of the encapsulated electrophoretic medium; (c) bonding a processor die to the vicinity of the plurality of display segment electrodes; (d) depositing interconnects such that the processor die is electrically connected to each of the plurality of display segment electrodes, such that the processor die can selectively apply voltage to the display segment electrodes to drive respective associated portions of the encapsulated electrophoretic medium between different optical states; and (e) applying a back protective sealing layer above the processor die and the interconnects such that the back protective sealing layer and the integrated barrier layer encapsulate the electroactive layer, the plurality of display segment electrodes, the interconnects, and the processor die.

20. The method of claim 19, wherein the conductive integrated barrier layer comprises a combination of a light-transmitting conductive material and a flexible moisture-proof layer.

21. The method of claim 19, wherein the electroactive layer comprises a plurality of microcells filled with an electrophoretic fluid and sealed by a sealing layer.

22. The method of claim 19, wherein forming the electroactive layer comprises: (i) Imprinting microcells onto a polymer film; (ii) Fill the microcells with an electrophoretic fluid; (iii) Seal the microcells with a polymer sealing layer.

23. The method of claim 19, wherein the electroactive layer comprises a plurality of microcapsules dispersed in a polymer binder, the microcapsules containing an electrophoretic fluid.

24. The method of claim 19 further includes encapsulating an electrophoretic medium in microcapsules and dispersing the microcapsules in a binder to form a slurry, wherein step (a) includes coating the conductive integrated barrier layer with the slurry.

25. The method of claim 19 further includes forming a color filter array on one side of the conductive integrated barrier layer prior to step (a).

26. The method of claim 19 further includes depositing a dielectric layer around the processor die.

27. The method of claim 19 further includes depositing a dielectric layer over the selected portions of the display segment electrodes prior to step (c).

28. The method of claim 19 further includes, prior to step (d), depositing a packaging material over the processor die and the interconnects.

29. The method of claim 19, wherein the plurality of display segment electrodes are deposited directly on the back side of the electroactive layer, with no substrate in between.

30. The method of claim 19, wherein the plurality of display segment electrodes are deposited directly on the back side of the electroactive layer without any adhesive in between.

31. The method of claim 19 further includes forming an edge seal around the integrated barrier layer and the rear protective seal layer to prevent the ingress of moisture or contaminants.

32. The method of claim 31, wherein forming the edge seal includes applying a seal around the periphery of the display, the seal extending between the integrated barrier layer and the rear protective seal.

33. The method of claim 31, wherein forming the edge seal includes pressing the integrated barrier layer together with the peripheral edge of the rear protective seal.

34. A flexible segmented electrophoretic display constructed according to any one of claims 19-33.

35. A flexible segmented electrophoresis display, comprising: An electroactive layer having a front viewing side and an opposite rear side, the electroactive layer including an encapsulated electrophoretic medium; A transparent common electrode layer superimposed on the front viewing side of the electroactive layer; a plurality of display segment electrodes directly adjacent to the rear side of the electroactive layer, each of the display segment electrodes being associated with an adjacent portion of the encapsulated electrophoretic medium; a processor die electrically connected to each of the plurality of display segment electrodes to apply voltage to the selected display segment electrode, thereby driving the respective portions of the encapsulated electrophoretic medium between different optical states; and a protective seal encapsulating the electroactive layer, the transparent common electrode layer, the plurality of display segment electrodes, and the processor die.

36. The display of claim 35, wherein the encapsulated electrophoretic medium comprises an electrophoretic medium encapsulated within microcapsules dispersed in a polymer binder or contained in sealed microcells.

37. The display as claimed in claim 35, wherein the processor die has a thickness of less than 100 μm.

38. The display as claimed in claim 35, wherein the processor die has a thickness of less than 50 μm.

39. The display as claimed in claim 35, wherein there is no air gap between the processor die and the protective seal.

40. The display of claim 35, wherein the processor die is fixed to the electrophoretic display via a flip-chip bonding process.

41. The display as claimed in claim 35, wherein the protective seal comprises a low water vapor transmission rate (WVTR) edge sealing resin.

42. The display of claim 35, wherein the processor die is mounted on a flexible carrier film that provides fan-out for the processor die wiring to facilitate electrical connection to the display segment electrodes.

43. The display of claim 35, wherein the processor die is electrically connected to each of the plurality of display segment electrodes via interconnects including printed conductive ink.

44. The display as claimed in claim 43, wherein the interconnects are deposited using a pulse printing process.

45. The display of claim 35, wherein the display further includes additional interconnects that electrically connect the processor die to power and control input contacts at one edge of the protective seal.

46. ​​The display as requested in item 45, wherein the additional interconnects include conductive carbon, silver or copper.

47. The display as requested in item 46, wherein the power and control input contacts include power, ground, data and clock inputs.

48. The display of claim 35, wherein the protective seal includes a rear protective seal facing the rear side of the electroactive layer and a front protective seal facing the front viewing side of the electroactive layer.

49. The display of claim 48, wherein the front protective seal and the rear protective seal form a barrier edge seal for preventing the entry of moisture or contaminants.

50. The display as claimed in claim 49, wherein the barrier edge seal includes a compression edge seal.

51. The display of claim 35, wherein the plurality of display segment electrodes are deposited directly on the electroactive layer using an inkjet or screen printing process.

52. The display of claim 35 further includes a color filter array located between the electroactive layer and the light-transmitting common electrode layer.

53. The display as claimed in claim 35, wherein the electrodes of the display segments comprise conductive carbon.

54. The display of claim 35 further includes a dielectric layer selectively formed over the display segment electrodes, and wherein the processor die is bonded to the dielectric layer.

55. The display of claim 43 further includes an encapsulation material located between the protective seal and the processor die or the interconnects.

56. The display of claim 35, wherein the plurality of display segment electrodes are directly behind the electroactive layer, with no adhesive layer in between.

57. The display of claim 35, wherein the plurality of display segment electrodes are directly behind the electroactive layer, with no substrate in between.

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