CN117063116A - Electrophoretic display with narrow edge seal - Google Patents

Abstract

An electrophoretic display module is described that includes various types of backplanes and edge seals for protecting an electro-optic display from environmental contaminants. In particular, the disclosed module design allows for very narrow edge seals, i.e. thicknesses of less than 1mm. In one type of seal, the electro-optic layer is sandwiched between a back plate and a protective sheet, and the sealing material extends between the back plate and the protective sheet. In some cases, the protective sheet includes multiple layers of transparent material to provide physical protection and reduce water intrusion.

Description

Electrophoretic display with narrow edge seal

Citation of related application

The present application claims priority from U.S. provisional patent application Ser. No.63/187,972, filed on day 13 at 5 in 2021, and U.S. provisional patent application Ser. No.63/175,935, filed on day 16 in 4 in 2021. All patents and publications mentioned below are incorporated herein by reference in their entirety.

Background

The present application relates to an electrophoretic display with an edge seal. The application also provides a production process of the electrophoretic display.

The terms "bistable" and "bistable" are used herein in their conventional sense in the art to refer to displays comprising display elements having first and second display states, at least one optical property of which is different, such that after any given element is driven to assume its first or second display state with an addressing pulse of finite duration, that state will last at least several times (e.g. at least 4 times) the minimum duration of the addressing pulse required to change the state of that display element after the addressing pulse has terminated. Some particle-based electrophoretic displays supporting gray scale are shown in U.S. Pat. No.7,170,670 to be stable not only in their extreme black and white states, but also in their intermediate gray states, as well as in some other types of electro-optic displays. This type of display is properly referred to as "multi-stable" rather than bistable, but for convenience the term "bistable" may be used herein to encompass both bistable and multi-stable displays.

Numerous patents and applications assigned to or on behalf of the institute of technology (MIT), the company einker california, and related companies describe various techniques for encapsulated microcell electrophoresis and other electro-optic media. The encapsulated electrophoretic medium comprises a plurality of capsules, each capsule itself comprising an internal phase and a capsule wall surrounding the internal phase, wherein the internal phase contains electrophoretically-mobile particles in a fluid medium. Typically, the capsules themselves are held in a polymeric binder to form a coherent layer between the two electrodes. In microcell electrophoretic displays, charged particles and fluid are not encapsulated within microcapsules, but rather are held in a plurality of cavities formed within a carrier medium (typically a polymer film). The term "microcavity electrophoretic display" may be used to encompass both encapsulated electrophoretic displays and microcell electrophoretic displays. Techniques described in these patents and applications include:

(a) Electrophoretic particles, fluids, and fluid additives; see, for example, U.S. Pat. nos. 5,961,804;6,017,584;6,120,588;6,120,839;6,262,706;6,262,833;6,300,932;6,323,989;6,377,387;6,515,649;6,538,801;6,580,545;6,652,075;6,693,620;6,721,083;6,727,881;6,822,782;6,831,771;6,870,661;6,927,892;6,956,690;6,958,849;7,002,728;7,038,655;7,052,766;7,110,162;7,113,323;7,141,688;7,142,351;7,170,670;7,180,649;7,226,550;7,230,750;7,230,751;7,236,290;7,247,379;7,277,218;7,286,279;7,312,916;7,375,875;7,382,514;7,390,901;7,411,720;7,473,782;7,532,388;7,532,389;7,572,394;7,576,904;7,580,180;7,679,814;7,746,544;7,767,112;7,848,006;7,903,319;7,951,938;8,018,640;8,115,729;8,199,395;8,257,614;8,270,064;8,305,341;8,361,620;8,363,306;8,390,918;8,582,196;8,593,718;8,654,436;8,902,491;8,961,831;9,052,564;9,114,663;9,158,174;9,341,915;9,348,193;9,361,836;9,366,935;9,372,380;9,382,427;9,423,666;9,428,649;9,552,780;9,557,623;9,664,978;9,670,367;9,671,667;9,688,859;9,726,957;9,732,231;9,752,034;9,765,015;9,778,535;9,778,537;9,778,538;9,835,926;9,864,253;9,953,588;9,995,987;10,025,157;10,031,394;10,040,954;10,061,123;10,062,337;10,431,168;10,444,590; and 10,514,583; U.S. patent application publication No.2003/0048522;2003/0151029;2003/0164480;2004/0030125;2005/0012980;2009/0009852;2009/0206499;2009/0225398;2010/0148385;2011/0217639;2012/0049125;2013/0161565;2013/0193385;2013/0244149;2014/0011913;2014/0078024;2014/0078573; 2014/0078776; 2014/0104674; 2014/023978; 2015/0177590;2015/0185509; 2015/024374; 2015/0301425; and 2016/0170106;

(b) A capsule body, an adhesive and a packaging process; see, for example, U.S. Pat. nos. 5,930,026;6,067,185;6,130,774;6,172,798;6,249,271;6,327,072;6,392,785;6,392,786;6,459,418;6,839,158;6,866,760;6,922,276;6,958,848;6,987,603;7,061,663;7,071,913;7,079,305;7,109,968;7,110,164;7,184,197;7,202,991;7,242,513;7,304,634;7,339,715;7,391,555;7,411,719;7,477,444;7,561,324;7,848,007;7,910,175;7,952,790;7,955,532;8,035,886;8,129,655;8,446,664; and 9,005,494; U.S. patent application publication No.2005/0156340;2007/0091417; 2008/013092; 2009/012389; and 2011/0286081;

(c) Microcell structures, wall materials, and methods of forming microcells; see, for example, U.S. patent No.6,672,921;6,751,007;6,753,067;6,781,745;6,788,452;6,795,229;6,806,995;6,829,078;6,833,177;6,850,355;6,865,012;6,870,662;6,885,495;6,906,779;6,930,818;6,933,098;6,947,202;6,987,605;7,046,228;7,072,095;7,079,303;7,141,279;7,156,945;7,205,355;7,233,429;7,261,920;7,271,947;7,304,780;7,307,778;7,327,346;7,347,957;7,470,386;7,504,050;7,580,180;7,715,087;7,767,126;7,880,958;8,002,948;8,154,790;8,169,690;8,441,432;8,582,197;8,891,156;9,279,906;9,291,872;9,388,307;9,436,057;9,436,058;9,470,917;9,919,553; and 10,401,668; U.S. patent application publication No.2003/0175480;2003/0175481;2003/0179437;2003/0203101;2014/0050814; and 2016/0059442;

(d) Methods for filling and sealing microcells; see, for example, U.S. patent No.6,545,797;6,751,008;6,788,449;6,831,770;6,833,943;6,859,302;6,867,898;6,914,714;6,972,893;7,005,468;7,046,228;7,052,571;7,144,942;7,166,182;7,374,634;7,385,751;7,408,696;7,522,332;7,557,981;7,560,004;7,564,614;7,572,491;7,616,374;7,684,108;7,715,087;7,715,088;8,179,589;8,361,356;8,520,292;8,625,188;8,830,561;9,081,250;9,346,987; and 9,759,978; U.S. patent application publication No.2002/0188053; 2004/010024; 2004/0219306; and 2015/0098124;

(e) Films and subassemblies comprising electro-optic materials; see, for example, U.S. patent No.6,825,829;6,982,178;7,112,114;7,158,282;7,236,292;7,443,571;7,513,813;7,561,324;7,636,191;7,649,666;7,728,811;7,729,039;7,791,782;7,826,129;7,839,564;7,843,621;7,843,624;8,034,209;8,068,272;8,077,381;8,177,942;8,390,301;8,482,835;8,786,929;8,830,553;8,854,721;9,075,280;9,238,340;9,470,950;9,554,495;9,563,099;9,733,540;9,778,536;9,835,925;10,444,591; and 10,466,564; U.S. patent application publication No. 2007/0237972; 2009/0168067; and 2011/0164301;

(f) Backsheets, adhesive layers, and other auxiliary layers and methods for use in displays; 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;7,327,346;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;7,560,004;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;7,839,564;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;9,310,661;9,419,024;9,454,057;9,529,240;9,620,066;9,632,373;9,632,389;9,666,142;9,671,635;9,715,155;9,777,201;9,778,500;9,841,653;9,897,891;9,910,337;9,921,422;9,964,831;10,036,930;10,037,735;10,048,563;10,048,564;10,190,743;10,324,577;10,365,533;10,372,008;10,429,715;10,446,585;10,466,564;10,466,565;10,495,940;10,495,941;10,503,041; and 10,509,294; and U.S. patent application publication No.2002/0060321;2004/0085619;2004/0105036; 2005/012306; 2005/012563; 2006/0255322;2007/0052757; 2009/012389; 2009/0315044;2010/0177396;2011/0140744;2011/0187683; 2011/0292321; 2014/0078024;2014/0192000;2014/0210701;2014/0368753; 2015/0378135; and 2016/007775; international application publication No. WO 00/38000; european patent Nos. 1,099,207B1 and 1,145,072B1;

(g) Color formation and color adjustment; see, for example, U.S. Pat. nos. 6,017,584; 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;7,952,790;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;9,423,666;9,436,056;9,459,510;9,513,527;9,541,814;9,552,780;9,640,119;9,646,547;9,671,668;9,697,778;9,726,959;9,740,076;9,759,981;9,761,181;9,778,538;9,779,670;9,779,671;9,812,073;9,829,764;9,921,451;9,922,603;9,989,829;10,032,419;10,036,929;10,036,931;10,332,435;10,339,876;10,353,266;10,366,647;10,372,010;10,380,931;10,380,955;10,431,168;10,444,592;10,467,984;10,475,399;10,509,293; and 10,514,583; U.S. patent application publication No.2008/0043318;2008/0048970;2009/0225398;2010/0156780;2011/0043543;2012/0326957; 2013/02022378; 2013/0278995;2014/0055840; 2014/0078776; 2015/0103394; 2015/0116190; 2015/0124045; 2015/0268131; 2015/0301246;2016/0026062;2016/0048054; and 2016/011688;

(h) A method for driving a display; see, for example, U.S. Pat. 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;7,312,794;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;9,218,773;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;9,412,314;9,424,800;9,460,666;9,495,918;9,501,981;9,513,743;9,514,667;9,530,363;9,542,895;9,564,088;9,612,502;9,620,048;9,620,067;9,672,766;9,721,495;9,779,670;9,881,564;9,881,565;9,886,886;9,928,810;9,966,018;9,996,195;10,002,575;10,037,089;10,380,954;10,388,233;10,475,396; and 10,504,457; U.S. patent application publication No.2003/0102858; 2004/0246262; 2005/0253777;2007/0091418;2007/0103427;2007/0176912;2008/0024429;2008/0024482;2008/0136774;2008/0291129;2008/0303780;2009/0174651; 2009/032721; 2010/0194733;2010/0194789;2010/0220121;2010/0265561;2011/0063314;2011/0175875;2011/0193840;2011/0193841;2011/0199671;2011/0221740;2012/0001957;2012/0098740;2013/0063333;2013/0194250;2013/0249782;2014/0009817;2014/0085355;2014/0204012;2014/0218277; 2014/024910; 2014/0253425;2014/0293398;2015/0262255;2015/0262551; 2016/007465; 2016/0093253;2016/0140910; and 2016/0180777;

(i) Application of the display; see, for example, U.S. patent No.6,118,426;6,473,072;6,704,133;6,710,540;6,738,050;6,825,829;7,030,854;7,119,759;7,312,784;7,705,824;8,009,348;8,011,592;8,064,962;8,162,212;8,553,012;8,973,837;9,188,829;9,197,704;9,506,243;9,880,646; and 10,331,005; and U.S. patent application publication No.2002/0090980; 2004/019681; 2007/0285385;2013/0176288;2013/0221112; 2013/02343930; 2013/0235463; 2014/0049808;2014/0062391;2014/0206292; and 2016/0035291; international application publication No. WO 00/36560.

Many of the foregoing patents and applications recognize that the walls surrounding discrete microcapsules in an encapsulated electrophoretic medium may 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 polymeric material, and that the discrete droplets of electrophoretic fluid within such a polymer-dispersed electrophoretic display may be considered as capsules or microcapsules even if no discrete capsule film is associated with each individual droplet; see, for example, U.S. patent No.6,866,760. Thus, for the purposes of the present application, such polymer-dispersed electrophoretic media are considered a subclass of encapsulated electrophoretic media.

Although electrophoretic media are typically opaque (because, for example, in many electrophoretic media, the particles substantially block the transmission of visible light through the display) and operate in a reflective mode, many electrophoretic displays may be made to operate in a so-called "shutter mode" in which one display state is substantially opaque and one display state is light transmissive. See, for example, U.S. patent No.5,872,552;6,130,774;6,144,361;6,172,798;6,271,823;6,225,971; and 6,184,856. Dielectrophoretic displays similar to electrophoretic displays but which rely on variations in the strength of the electric field may operate in a similar mode; see U.S. patent No.4,418,346. Other types of electro-optic displays are also capable of operating in a shutter mode. In the multi-layer structure of a full-color display, an electro-optic medium operating in shutter mode may be useful; in such a configuration, at least one layer adjacent to the viewing surface of the display operates in a shutter mode to expose or hide a second layer farther from the viewing surface.

Encapsulated electrophoretic displays are generally free of the trouble of clustering and sedimentation failure modes of conventional electrophoretic devices and offer further benefits, such as the ability to print or coat displays on a variety of flexible and rigid substrates. (the use of the word "printing" is intended to include all forms of printing and coating including, but not limited to, pre-metered coating such as repair die coating, slot or extrusion coating, slide or stack coating, curtain coating, roll coating such as roller blade coating, forward and reverse roll coating, gravure coating, dip coating, spray coating, meniscus coating, spin coating, brush coating, air knife coating, screen printing processes, xerographic processes, thermal printing processes, ink jet printing processes, electrophoretic deposition (see U.S. patent No.7,339,715), and other similar techniques.) thus, the resulting display may be flexible. In addition, because the display medium can be printed (using a variety of methods), the display itself can be manufactured inexpensively.

One related type of electrophoretic display is the so-called "microcell electrophoretic display". In microcell electrophoretic displays, the charged particles and the suspending fluid are not encapsulated within microcapsules, but rather remain in a plurality of cavities formed within a carrier medium (typically a polymer film). See, for example, international application publication No. WO 02/01181 and published U.S. application No. 2002/007556, both assigned to Sipix Imaging company.

An electrophoretic display typically comprises a layer of electrophoretic material and at least two other layers, one of which is an electrode layer, disposed on opposite sides of the electrophoretic material. In most such displays, both layers are electrode layers, and one or both of the electrode layers are patterned to define the pixels of the display. For example, one electrode layer may be patterned as an elongate row electrode and the other electrode layer may be patterned as an elongate column electrode extending at right angles to the row electrode, the pixels being defined by the intersections of the row and column electrodes. Alternatively, and more typically, one electrode layer has the form of a single continuous electrode, while the other electrode layer is patterned into a matrix of pixel electrodes, each defining one pixel of the display. In another type of electrophoretic display intended for use with a stylus, printhead or similar movable electrode separate from the display, only one of the layers adjacent the electrophoretic layer includes an electrode, the layer on the opposite side of the electrophoretic layer typically being a protective layer intended to prevent the movable electrode from damaging the electrophoretic layer.

The fabrication of three-layer electrophoretic displays typically involves at least one lamination operation. For example, in several of the above MIT and E Ink patents and applications, a process is described for manufacturing encapsulated electrophoretic displays, in which an encapsulated electrophoretic medium comprising capsules in a binder is coated onto a flexible substrate comprising Indium Tin Oxide (ITO) or a similar conductive coating on a plastic film (acting as one electrode of the final display), the capsules/binder coating being dried to form a coherent layer of electrophoretic medium that adheres strongly to the substrate. A back plate comprising an array of pixel electrodes and a suitable conductor arrangement for connecting the pixel electrodes to a drive circuit is prepared separately. To form the final display, the substrate with the balloon/adhesive layer thereon is laminated to a back plate using a lamination adhesive. As a preferred form of this process (by replacing the back plate with a simple protective layer (e.g. a plastic film) a very similar process can be used to prepare an electrophoretic display that can be used with a stylus or similar movable electrode that can slide over it.) the back plate itself is flexible and is prepared by printing the pixel electrodes and conductors on a plastic film or other flexible substrate. An obvious lamination technique for mass production of displays by this process is roll lamination using lamination adhesive.

The aforementioned U.S. Pat. No.6,982,178 describes a method of assembling solid electro-optic displays, including particle-based electrophoretic displays, which is well suited for mass production. Essentially, this co-pending application describes a so-called "front plane laminate" ("FPL") that includes, in order, a light transmissive conductive layer, a solid electro-optic medium layer in electrical contact with the conductive layer, an adhesive layer, and a release sheet. Typically, the optically transparent conductive layer will be carried on an optically transparent substrate, which is preferably flexible in the sense that the substrate can be manually wound, for example, on a 10 inch (254 millimeter) diameter drum without permanent deformation. The term "light transmissive" is used in this patent to refer herein to a layer that transmits sufficient light so that a viewer can observe through the layer a change in the display state of the electro-optic medium, which will typically be observed through the conductive layer and adjacent substrate (if present). The substrate is typically a polymeric film and will typically have a thickness in the range of about 1 to about 25 mils (25 to 634 μm), preferably about 2 to about 10 mils (51 to 254 μm). The conductive layer is typically a thin metal layer such as aluminum or ITO, or may be a conductive polymer. Polyethylene terephthalate (PET) films coated with aluminum or ITO are commercially available, for example, as "aluminized Mylar" by dupont of Wilmington DE ("Mylar" is a registered trademark), and such commercial materials can be used with good results in front plane laminates.

The term "impulse" as used herein has the conventional meaning of an integral of voltage with respect to time. However, some bistable electro-optic media are used as charge converters, and with such media an alternative definition of impulse, i.e. integration of current with respect to time (equal to the total charge applied), can be used. Depending on whether the medium is used as a voltage-to-time impulse converter or as a charge impulse converter, the appropriate impulse definition should be used. The term "waveform" will be used to refer to the entire voltage-time curve used to effect a transition from one particular initial gray level to a particular final gray level. Typically such waveforms will comprise a plurality of waveform elements; wherein the elements are substantially rectangular (i.e., wherein a given element comprises a constant voltage applied over a period of time); these elements may be referred to as "pulses" or "drive pulses". The term "drive scheme" means a set of waveforms sufficient to achieve all possible transitions between gray levels of a particular display. The display may use more than one driving scheme; for example, the above-mentioned U.S. Pat. No.7,012,600 teaches that the drive scheme may need to be modified according to parameters such as the temperature of the display or the time that it has been operated during its lifetime, and thus the display may be provided with a plurality of different drive schemes for use at different temperatures, etc. A set of drive schemes used in this manner may be referred to as a "set of related drive schemes". As described in the several MEDEOD applications above, more than one drive scheme may also be used simultaneously in different areas of the same display, and a set of drive schemes used in this manner may be referred to as a "set of synchronous drive schemes.

Another complication in driving an electrophoretic display is the need for so-called "DC balancing". As discussed in the aforementioned U.S. patent nos. 6,531,997 and 6,504,524, problems may be encountered if the method used to drive the display cannot result in zero or near zero net time-averaged electric field applied to the electro-optic medium and the operating life of the display may be shortened. The driving method that results in zero net time-averaged electric field applied to the electro-optic medium is conveniently referred to as "direct current balancing" or "DC balancing".

The aforementioned U.S. Pat. No.6,982,178 also describes the importance of protecting electro-optic media from environmental contaminants, as some electro-optic media are sensitive to humidity and ultraviolet radiation, and most such media are susceptible to mechanical damage. This published application shows in fig. 10 a process in which a protective film is laminated to a front plane laminate in the same lamination operation as the front plane laminate is laminated to a back sheet; such protective films may protect the electro-optic medium from moisture, other liquids, and some gases. However, even with such protective films, the edges of the electro-optic medium remain exposed to the environment, and the published application teaches that it is also desirable for the display to include an edge seal for preventing intrusion of moisture and other contaminants around the outer edges of the display. Figures 11-17 of U.S. patent 6,982,178 illustrate various types of edge seals. The edge seal may be comprised of a metallized or other barrier foil adhered to the edge of the FPL, a dispensed sealant (thermally, chemically and/or radiation cured), a polyisobutylene or acrylate based sealant, or the like. It has been found that mixing radiation and thermally curing the encapsulant (i.e., uv curing with a post-thermal bake) provides certain advantages to the performance of the display system. The Threebond 30Y-491 material (from Threebond corporation, cincincinnati, ohio) is particularly preferred because of its advantageous water vapor barrier properties, low viscosity at high temperatures for facilitating dispensing of the edge sealing material, good wetting characteristics, and controlled curing properties. Those skilled in the art of advanced sealants will be able to identify other sealants that provide comparable performance. An exemplary edge seal having a width of about 2.5mm is shown in fig. 1.

Fig. 20 of the aforementioned U.S. patent 6,982,178 shows a preferred form of electro-optic display having a front protective layer and an edge seal. The preferred display includes a Thin Film Transistor (TFT) backplane generally similar to that used in liquid crystal displays and having a matrix of pixel electrodes and associated thin film transistors and conductors for independently controlling voltages applied to the pixel electrodes. The tape connection package is connected to the outer peripheral portion of the back plate and provided with a driving integrated circuit (controlling the operation of the display); the tape connection package is also connected to a printed circuit board that contains additional circuitry for controlling the operation of the display.

The upper surface of the back plate (as shown in fig. 20) is provided with a layer of laminating adhesive, a layer of electro-optic medium, a front electrode and a front substrate; both the front electrode and the front substrate are conveniently formed from indium tin oxide coated polymer films, and as already noted, such coated films are readily commercially available. The lamination adhesive layer, electro-optic layer, front electrode, and front substrate are all from a front sheet laminate that has been laminated to the back sheet. The front electrode and a portion of the front substrate extend beyond the electro-optic layer, and in the extending portion of the front electrode and the front substrate, a conductive via formed of silver ink electrically connects the front electrode to a circuit provided on the back plate, while an adhesive layer secures the extending portion of the front electrode to the back plate.

A first layer of optically clear adhesive, a barrier film, a second layer of optically clear adhesive, and another relatively thick protective film provided with an antiglare coating on its exposed surface are sequentially disposed on the front substrate. The protective film functions to block ultraviolet radiation from reaching the electro-optic layer and also prevents atmospheric moisture or other contaminants from reaching the layer.

To form a complete seal around the electro-optic layer, the barrier film, the second layer of optically clear adhesive, and the protective film are made larger than the front substrate in both dimensions such that the layers have peripheral portions that extend or "overhang" the outer edges of the front substrate. To complete the seal of the electro-optic layer, a curable edge sealing material is typically injected into the overhanging region via a needle dispenser and cured to form an edge seal that completely surrounds the electro-optic layer.

This type of edge seal is effective in preventing moisture and other environmental contaminants from penetrating the electro-optic medium. However, one of the advantages of encapsulated electrophoretic and other electro-optic media (e.g., rotating bichromal members and microcell media) is that they are flexible enough for flexible displays. Edge seals of the type described above and similar are not suitable for use in flexible displays because the edge seal itself imparts rigidity to the display.

Further improvements to edge seals in electro-optic displays in general, and electrophoretic displays in particular, can be found in U.S. patent No.7,649,674, the entire contents of which are incorporated herein by reference. The' 674 patent describes a number of different edge seal designs, including overlapping seal materials, single and double seal protection sheets, single and double adhesive seals, and tape seals. For example, FIG. 2 shows a schematic cross-sectional view of the single seal protective sheet display (generally designated 200) disclosed in the' 674 patent. The display 200 includes a back plane 202, a layer of laminating adhesive 204, a layer of electro-optic material 206, and a front substrate 208 including light transmissive conductors, and the back plane 202. The back plane 202 may include an array of pixels coupled to thin film transistors. Notably, the back plate 202 is much wider than the layers 204-208, the layers 204-208 having been deposited as part of a front plane laminate, such as described above. Due to this configuration, the substantially peripheral portion 202P extends far beyond the edge of the active area of the electro-optic material layer 206. This extra area is often referred to as a "dead zone" because it occupies a portion of the display but cannot be switched between optical states (see fig. 1). In this document, the width of the seal edge is generally denoted D _ES . In many cases, this dead space is covered by a decorative cover, such as a housing, frame or bezel.

The display 200 also includes a front protective or barrier sheet 210 that also includes a peripheral portion 210P that extends outwardly beyond the edges of the layers 204-208. The peripheral portion 210P of the front barrier sheet 210 is sealed to the peripheral portion 202P of the back plate 202, for example, by melting an appropriate portion of the front barrier sheet using, for example, laser or ultrasonic welding. Alternatively, the peripheral portions 210P and 202P may be fixed to each other with an adhesive.

As is evident from fig. 2, the edge seal width D _ES In many respects, is determined by the thickness and flexibility of the front protective or barrier sheet 210. In addition, the method of sealing the peripheral portion of the substrate 202P to the peripheral portion of the front protective or barrier sheet 210P determines how closely the substrate 202 may be cut from the edge of the electro-optic material layer 206. If a soldering method is used, the overall width of the substrate may be reduced, however, if an adhesive is provided between 210P and 202P, a larger edge seal may be required. (it is certain that in a mass produced display module, as shown in FIG. 1, the front plane laminate is cut to allow enough margin to seal to the previously fabricated TFT backplate, rather than otherwise.)

As with many modern electronic displays, such as mobile phones, televisions, computer monitors, electrophoretic displays are required to have thinner and thinner frames. In fact, in some applications, the edge seal width limits the width of the bezel or frame that must be used. In addition, the edge seal width has a great impact on customer acceptance when the electrophoretic displays are tiled together. For high-end applications such as digital photography and artwork, large format high resolution electrophoretic displays with non-switching lines across the middle are not acceptable at all.

Disclosure of Invention

The invention provides an electrophoretic display comprising an integrated back plate, an electrophoretic material layer disposed adjacent to the integrated back plate, a light transmissive electrode layer adjacent to the electrophoretic material layer, and a pre-integration barrier. The integrated back plate includes a back electrode layer, an adhesive layer, a metal foil layer, and a substrate. The pre-integration barrier includes a top protective layer, a moisture barrier, and an optically clear adhesive, where the optically clear adhesive bonds the moisture barrier to the integrated backsheet to create an edge seal. In some embodiments, the pre-integration barrier is deformed at the edges to encapsulate the electrophoretic material layer and the light transmissive electrode layer in the central portion while bonding the moisture barrier and the integrated backplate along the edges of the electrophoretic display. In some embodiments, the distance between the edge of the light transmissive electrode layer and the outer edge of the integrated back plate is 1mm or less. In some embodiments, the distance between the edge of the light transmissive electrode layer and the outer edge of the integrated back plate is 0.5mm or less. In some embodiments, the electrophoretic display further comprises a lamination adhesive layer between the integrated back sheet and the layer of electrophoretic material. In some embodiments, the metal foil is gold foil, silver foil, aluminum foil, or copper foil. In some embodiments, the back electrode layer comprises indium tin oxide, conductive carbon, graphene, nanotubes, metal whiskers, or poly (3, 4-ethylenedioxythiophene). In some embodiments, the electrophoretic material comprises two or more groups of charged particles that move in response to an electric field, wherein each group of charged particles has different optical properties. In some embodiments, the electrophoretic material comprises three or more groups of charged particles that move in response to an electric field, wherein each group of charged particles has different optical properties.

In another aspect, the present invention provides an electrophoretic display comprising an integrated rear barrier, a rear electrode layer, an electrophoretic material layer disposed adjacent to the rear electrode layer, and a light transmissive electrode layer adjacent to the electrophoretic material layer on a side opposite the rear electrode layer, and an integrated front barrier. The integrated rear barrier includes a rear protective layer, a rear moisture barrier, and a rear lamination adhesive. The integrated front barrier includes a top protective layer, a front moisture barrier, and an optically clear adhesive, wherein the optically clear adhesive bonds the front moisture barrier and the back electrode layer to form an edge seal. In some embodiments, the front barrier is deformed at the edges to encapsulate the electrophoretic material layer and the light transmissive electrode layer in the central portion while bonding the front moisture barrier and the back electrode layer along the edges of the electrophoretic display. In some embodiments, the distance between the edge of the light transmissive electrode layer and the outer edge of the post-integration barrier is 1mm or less. In some embodiments, the distance between the edge of the light transmissive electrode layer and the outer edge of the post-integration barrier is 0.5mm or less. In some embodiments, the electrophoretic display further comprises a lamination adhesive layer between the back electrode layer and the layer of electrophoretic material. In some embodiments, the back electrode layer is light transmissive. In some embodiments, the back electrode layer comprises indium tin oxide, conductive carbon, graphene, nanotubes, metal whiskers, or poly (3, 4-ethylenedioxythiophene). In some embodiments, the electrophoretic material comprises two or more groups of charged particles that move in response to an electric field, wherein each group of charged particles has different optical properties. In some embodiments, the electrophoretic material comprises three or more groups of charged particles that move in response to an electric field, wherein each group of charged particles has different optical properties.

Drawings

Fig. 1 shows a commercial electrophoretic display module and a caliper for measuring the edge seal width.

Fig. 2 shows a prior art electrophoretic display comprising a protective sheet and an edge seal. The width of the edge seal is shown as D _ES 。

Fig. 3 shows an improved electrophoretic display design that allows for a reduced edge seal width.

Fig. 4 shows an improved electrophoretic display design that allows for a reduced edge seal width.

Fig. 5 shows an improved electrophoretic display design that allows for a reduced edge seal width.

Fig. 6 shows an improved electrophoretic display design that allows for a reduced edge seal width.

Fig. 7A and 7B illustrate a method for reducing the edge seal width of the electrophoretic display module of fig. 5.

Fig. 8A and 8B illustrate a method for reducing the edge seal width of the electrophoretic display module of fig. 6.

It should be emphasized that all the figures are schematic and not drawn to scale. In particular, for ease of illustration, the thicknesses of the various layers in the drawings do not correspond to their actual thicknesses. Moreover, in all the figures, the thickness of the various layers is greatly exaggerated relative to their lateral dimensions.

Detailed Description

As discussed in the background, there are a number of methods of sealing an electrophoretic display using a combination of substrates, edge seal materials, and assembly techniques. The electrophoretic display described herein provides a narrow edge seal, thereby reducing the width of material at the inactive edge of the sealed electrophoretic display.

For the purposes of the ensuing discussion, the term "backplane" as used herein is consistent with its conventional meaning in the field of electro-optic displays and in the aforementioned patents and published applications, meaning a rigid or flexible material having one or more electrodes. The back plate may also be provided with electronics for addressing the display, or such electronics may be provided in a separate unit from the back plate. In electrophoretic displays, it is highly desirable that the back-plate provide sufficient barrier properties to prevent intrusion of moisture and other contaminants through the non-viewing side of the display (of course, the display is typically viewed from the side opposite the back-plate).

As discussed in the aforementioned U.S. patent nos. 6,982,178 and 7,110,164 and patent publication No.2004/0155857, a preferred form of front substrate for an electro-optic display comprises a thin layer of ITO on PET, such coated films being readily commercially available. In such front substrates, the ITO layer acts as a barrier material, but in practice commercial PET/ITO inevitably suffers from pinholes and cracks through which moisture and other contaminants may penetrate into the electro-optic material.

To increase the sealing properties of such PET/ITO or similar front substrates, it is necessary to laminate onto the front substrate an excess barrier layer made of a homopolymer (e.g., polytrifluoroethylene available from Honeywell under the registered trademark "ACLAR") or a sputtered ceramic (e.g., alO available from Toppan Printing under the trade name Toppan GX Film) _x ) And (5) forming. The excess barrier layer should be thin to provide a flexible display, ideally about 12 μm, but can be as thick as 5 mils (127 μm) if sufficient flexibility is still provided. When an adhesive layer is required to attach the excess barrier to the front substrate, the adhesive layer should be transparent, colorless, thin, flexible, have low creep (when the display is bent or otherwiseCurl) and is durable at all temperatures within the operating range of the display. Certain crosslinked polyurethanes and polyacrylates are useful as such adhesives.

Alternatively, the barrier properties of the PET/ITO or similar front substrate may be improved by coating an excess metal oxide layer (e.g., an aluminum oxide layer) on the surface of the front substrate opposite the ITO layer or underneath the ITO layer. The combination of the ITO layer and the excess metal oxide layer improves the barrier properties of the front substrate (e.g., by reducing migration of water vapor through unavoidable cracks and pinholes in the ITO layer) without causing excessive yellowing of the substrate, as would occur, for example, if an attempt were made to increase the barrier properties by increasing the thickness of the ITO layer. Instead of a simple metal oxide layer, a more complex structure comprising a ceramic material, such as a Barix (registered trademark) sealing material available from Vitex Systems company (3047Orchard Parkway,San Jose,CA 95134), may be used; also, a barrier layer may be disposed on the surface of the front substrate remote from the ITO layer or below the ITO layer. Vitex Systems currently sell a polymer film carrying both Barix and ITO layers under the trade name FlexGlass 200, but the polymer film is 5mil (127 μm) polyethylene naphthalate (PEN).

The barrier properties of the front substrate, such as flexibility, cost, and other specialized properties, may also be controlled by careful selection of both the polymer and conductive material used in the front substrate. In principle, almost any flexible, light-transmitting polymer can be used; suitable polymers include PET, PEN, polycarbonate, polyvinylidene chloride (sold under the registered trademark "SARAN"), polytrifluoroethylene (sold under the registered trademarks "ACLAR" and "CLARIS"), triacetylcellulose, the material sold by JSR corporation under the registered trademark "ARTON", polyethersulfone (PES), and laminates of two or more of these materials. Suitable transparent conductive materials include ITO, organic conductive polymers such as Baytron P (registered trademark), carbon nanotubes, and electrical resistivity less than about 10 ⁴ Other suitable conductive light transmitting conductors (transmittance greater than 60%) are ohmic/square.

The preferred display of the present invention will now be described by way of illustration only with reference to the accompanying drawings. In all cases, the electrophoretic layer may be an encapsulated electrophoretic layer, a polymer dispersed electrophoretic layer, or any other type of electro-optic layer discussed above. The electrophoretic layer may be contained in microcells defined by micro-embossing a polymer (e.g., acrylate), filling the microcells with an electrophoretic medium, and then sealing the microcells to contain the electrophoretic medium. The display may include one or two (or more) laminated adhesive layers to attach the layers of the electrophoretic display to each other or to the front substrate and/or the back sheet. The display may be viewed through either of the laminated adhesive layers and may be assembled by direct coating and lamination or by using a front plane laminate, an inverted front plane laminate or a dual release film, as described above.

The type of electrophoretic material included in the disclosed electrophoretic display is not limited. For example, an electrophoretic medium of the present invention may comprise two oppositely charged particles having different optical properties (e.g., black and white). However, the colors incorporated into the electrophoretic medium are not limited and may include, for example, red, orange, yellow, green, blue, violet, brown, pink, magenta, cyan, and the like. The electrophoretic medium may comprise three or more sets of different electrophoretic materials, such as described in U.S. Pat. nos. 9,921,451 and 9,812,073, the entire contents of which are incorporated herein by reference.

Fig. 3 is a schematic diagram of an electrophoretic display (generally designated 300) of the present invention. The display 300 includes an integrated back plate 320, a layer of electrophoretic material 306, a layer of lamination adhesive 304, a layer of light transmissive electrode 308, and an integrated front barrier 310. The integrated back plate 320 includes a back electrode layer 326, a polymer layer 324, a metal foil layer 322, and a substrate 321. The integrated back-plate 320 can additionally include an adhesive layer between the metal foil layer 322 and the substrate 321. The light transmissive electrode layer 308 may comprise Indium Tin Oxide (ITO) sputtered onto thin polyethylene terephthalate (PET), or it may comprise another light transmissive electrode material such as conductive carbon, graphene, nanotubes, metal whiskers, or poly (3, 4-ethylenedioxythiophene (PEDOT)). The PET may be 50 μm thick or less, for example 30 μm thick or less, 25 μm thick or less, or 20 μm thick or less. In some cases, the conductive material (e.g., metal whiskers) are distributed in a transparent polymer matrix. The metal foil layer can include gold foil, silver foil, aluminum foil, or copper foil. The integrated back-plate 320 is not limited to the configuration described with reference to fig. 3, and may additionally include one or more additional flexible substrates, one or more additional adhesive layers, and one or more additional metal layers. In some cases, the integrated back plate 320 is flexible and may deform around the electrophoretic material layer 306 and the light transmissive electrode layer 308 to engage with the pre-integrated barrier 310.

The pre-integration barrier 310 includes a top protective layer 311, a moisture barrier 314, and an optically clear adhesive 312. The pre-integration barrier may include a second optically clear adhesive 316 between the top protective layer 311 and the moisture barrier 314. The peripheral portion 318 of the pre-integration barrier is deformed to encapsulate the electrophoretic material layer 306 and the light transmissive electrode layer 308 in a central portion while bonding the moisture barrier 314 and the integrated backplate 320 along the edges of the electrophoretic display. The top protective layer 311 may be any transparent deformable polymeric material such as polyethylene, polyacrylate, or polystyrene.

Edge seal distance D _ES May be defined as the minimum distance between the edge of the light transmissive electrode layer 308 and the edge of the pre-integration barrier 310, or simply the distance between the edge of the light transmissive electrode layer 308 and the furthest extent of the top protective layer 311, in some cases the top protective layer 311 may extend slightly beyond the moisture barrier 314. With the configuration shown in fig. 3, it is possible to achieve a narrow edge seal, e.g., where D _ES Is 2mm or less, such as 1mm or less, such as 0.5mm or less, such as 0.2mm or less. It exhibits an edge seal thickness that is 3 to 10 times thinner when compared to the prior art, for example, of fig. 1. Such a narrow edge seal is beneficial when the display is integrated into other devices for use as a color changing ornament or indicator, or when the display is in contact (e.g., tiled). Narrow edge seals may also be required in cases where the surface area is limited, such as in jewelry or when integrated into a closely looking surface (e.g., sunglasses or eyeglasses for augmented reality). In some cases, an electrophoretic display The edges of the peripheral region 318 will be further finished, for example, using laser ablation or ion beam ablation to further reduce the width of the peripheral region. The exposed surface at the interface of the pre-integration barrier 310 and the integrated backplate 320 may be sealed with an edge barrier 340, and the edge barrier 340 may be a high density polymer sealant such as an acrylic, such as cyanoacrylate, or polyurethane, or a sealing tape. In some embodiments, edge barrier 340 may be a deposited material such as silicon nitride, aluminum oxide, or silicon oxide.

A second embodiment of the electrophoretic display of the invention is shown in fig. 4. The display 400 includes an integrated rear barrier 420, a rear electrode layer 430, an electrophoretic material layer 406, a lamination adhesive layer 404, a light transmissive electrode layer 408, and an integrated front barrier 410. The integrated rear barrier 420 includes a rear protective layer 421, a rear moisture barrier 424, and a rear lamination adhesive 422. The transparent electrode layer 408 and the back electrode layer 430 may both or alternatively comprise Indium Tin Oxide (ITO) sputtered onto thin polyethylene terephthalate (PET), or they may comprise another transparent electrode material such as conductive carbon, graphene, nanotubes, metal whiskers, or poly (3, 4-ethylenedioxythiophene (PEDOT)). The rear electrode layer 430 may be opaque. In some embodiments, the light transmissive electrode layer 408 and the back electrode layer 430 are 50 μm thick or less, such as 30 μm thick or less, 25 μm thick or less, or 20 μm thick or less, respectively.

The pre-integration barrier 410 includes a top protective layer 411, a moisture barrier 414, and an optically clear adhesive 412. The pre-integration barrier 410 may include a second optically clear adhesive 416 between the top protective layer 411 and the moisture barrier 414. The outer peripheral portion 418 of the integrated front barrier is deformed to encapsulate the electrophoretic material layer 406 and the light transmissive electrode layer 408 in a central portion while bonding the moisture barrier layer 414 and the rear electrode layer 430 along the edges of the electrophoretic display. The top protective layer 411 may be any transparent deformable polymeric material such as polyethylene, polyacrylate, or polystyrene.

Similar to fig. 3, the width of the edge seal in the embodiment of fig. 4 is the minimum distance between the edge of the transparent electrode layer 408 and the edge of the rear electrode layer 430 or the integrated rear barrier 420 (taken the one extending further outward from the edge of the transparent electrode 408). The exposed surfaces at the interface of the pre-integration barrier 410 and the post-integration barrier 420 may be sealed with an edge barrier 440, for example, as described above with reference to fig. 3.

Fig. 5 shows an alternative edge seal to that of fig. 3. In fig. 5, the pre-integration barrier 510 is deformed at the edge toward the integration back plate 520, while the integration back plate 520 is deformed toward the pre-integration barrier 510. This configuration may be referred to as a "pinch-edge" seal. Similar to fig. 3, display 500 of fig. 5 includes an integrated back plate 520, an electrophoretic material layer 506, a light transmissive electrode layer 508, and an integrated front barrier 510. The integrated backplate 520 includes a back electrode layer 526, a polymer layer 524, a metal foil layer 522, and a substrate 521. The integrated backplate 520 can additionally include an adhesive layer between the metal foil layer 522 and the substrate 521. The integrated backplate 520 is not limited to the configuration described with reference to fig. 5, and may additionally include one or more additional flexible substrates, one or more additional adhesive layers, and one or more additional metal layers. The pre-integration barrier 510 includes a top protective layer 511, a moisture barrier 514, and an optically clear adhesive 512. The pre-integration barrier 510 may include a second optically clear adhesive 516 between the top protective layer 511 and the moisture barrier 514. The outer peripheral portion 518 of the pre-integration barrier is deformed to encapsulate the electrophoretic material layer 506 and the light transmissive electrode layer 508 in a central portion while bonding the moisture barrier 514 and the integrated backplate 520 along the edges of the electrophoretic display. The top protective layer 511 may be any transparent deformable polymeric material such as polyethylene, polyacrylate, or polystyrene. With the configuration shown in fig. 5, it is possible to achieve a narrow edge seal, e.g., where D _ES Is 2mm or less, such as 1mm or less, such as 0.5mm or less, such as 0.2mm or less. In some cases, the edges of the electrophoretic display will be further finished, for example, with laser ablation or ion beam ablation to further reduce the width of the peripheral region 518. The exposed surface at the interface of pre-integration barrier 510 and integrated back plate 520 may be sealed with edge barrier 540, and edge barrier 540 may be a high density polymer sealant such as acrylic, e.g., cyanoacrylate, or polyurethane, or a sealing tape.

In a different embodiment, a pinch-edge seal similar to that of fig. 5 is formed after removing the back electrode layer 526 and the polymer layer 524 from the portion of the display that extends beyond the electrophoretic material layer 506 and the lamination adhesive 504, as illustrated in fig. 6. The post-integration barrier 620 includes a metal foil layer 522 and a substrate 521, and an optional adhesive layer (not shown). As shown in fig. 5, the pre-integrated barrier 510 includes a top protective layer 511, a moisture barrier 514, and an optically clear adhesive 512. The peripheral portion 518 of the pre-integration barrier 510 is deformed toward the post-integration barrier 620 and a portion of the post-integration barrier 620 is deformed toward the pre-integration barrier 510 to encapsulate the layers of electrophoretic material layer 506, light transmissive electrode layer 508, and laminating adhesive 504 in a central portion while bonding the moisture barrier 514 and metal foil layer 524 along the edges of the electrophoretic display with optically clear adhesive layer 512. The resulting stack is thinner, allowing for a narrower edge seal. It should be appreciated that the deflection of the pre-integration barrier 510 and the deflection of the post-integration barrier need not be symmetrical.

A method of forming a narrow pinch edge seal comprising an integrated back plate of display 500 is shown in fig. 7A. In this case, the peripheral portion 518 has been extended, which is merely a matter of using a larger portion of both the pre-integration barrier 510 and the integrated backplate 520. After the seal is formed between the transparent adhesive 512 and the back electrode layer 526, the edge seal is cut with a laser 710 (or another cutting tool) to reduce the edge seal width. However, the resulting foil/backsheet layer 720 may not provide a good seal, thus forming an edge barrier 540 that contacts the exposed edge of the pre-integrated barrier 510 and the metal foil layer 522, as shown in fig. 7B. This same edge seal approach may be used in any of the displays described above, such as those shown in fig. 3-6. Additionally, in some embodiments, the metal foil layer 522 can be electrically coupled to the back electrode layer 526 to allow easy external connection to the back electrode layer.

An alternative method of forming a narrow pinch edge seal comprising an integrated back plate of display 600 is shown in fig. 8A. In this case, the peripheral portion 518 has been extended, which is only a matter of using a larger portion of both the integrated front barrier 510 and rear barrier 520. After the seal is formed between the moisture barrier 514 and the metal foil layer 522, the edge seal is cut with a laser 710 (or another cutting tool) to reduce the edge seal width. In some embodiments, an edge barrier 740 is formed that contacts the exposed edge of the pre-integrated barrier 510 and the metal foil layer 522, as shown in fig. 8B. In some embodiments, the metal foil layer 522 can be electrically coupled to the back electrode layer 526 to allow easy external connection to the back electrode layer. In yet another alternative configuration, the structure of fig. 8B may be formed by: the back barrier layer 620 is cut before the back barrier layer 620 is assembled with the rest of the display 600 and then the integrated front barrier 510 and back barrier layer 620 are kneaded together so that the moisture barrier 514 is sealed to the metal foil layer 522.

The electrophoretic display of the present invention may be substantially rigid or the material may be selected to allow the display to bend. Such a display does not require a thick, rigid sealing member of the kind present in some prior art displays and the peripheral portions of the back plate and the barrier sheet or sheets, which are adhered to each other, can remain flexible as long as the back plate is sufficiently flexible. In some applications, the entire stack may be optically transmissive except for portions of the electrophoretic medium (i.e., the charged pigment particles). In some embodiments, the electrophoretic medium may comprise only one type of particle, and the display may be designed to provide a suitable electric field to move the pigment particles to a "shutter" state in which the viewing area becomes substantially transparent.

The electrode arrangements in the various types of displays of the present invention may be of any of the types described in the aforementioned Eink and MIT patents and applications. Thus, for example, the display may be of the direct drive type, wherein the backplate is provided with a plurality of electrodes, each electrode being provided with a separate connector through which the controller can control the voltage applied to a particular electrode. In such direct drive displays, a single continuous front electrode is typically provided covering the entire display, but other front electrode arrangements are possible. Depending on the type of electro-optic material used, a passive matrix drive arrangement may be used in which the (typically) back plate carries a plurality of elongate parallel electrodes ("column electrodes") and a plurality of elongate parallel electrodes ("row electrodes") extending at right angles to the column electrodes are provided on opposite sides of the electro-optic material, the overlap between a particular column electrode and a particular row electrode defining a pixel of the display. The display of the invention may also be of the active matrix type, typically having a matrix of pixel electrodes on a single continuous front electrode and back plate covering the entire display, each pixel electrode defining a pixel of the display and having an associated transistor or other non-linear element, the active matrix display being scanned in a conventional manner to write the display in a row-by-row manner. Finally, the display of the present invention may also be of the stylus driven type. Writing of the display is achieved by moving the stylus over the front surface of the display, with (typically) a single electrode on the backplate and no permanent front electrode.

The display of the invention may be used in any application where the electro-optic displays of the prior art are used. Thus, for example, the display of the present invention may be used in electronic book readers, portable computers, tablet computers, mobile phones, smart cards, signs, watches, shelf labels, and flash memory drives.

Many changes and modifications may be made to the preferred embodiment of the invention that has been described without departing from the scope of the invention. The preceding description is, therefore, to be construed as illustrative, and not restrictive.

Claims (20)

1. An electrophoretic display, comprising:

an integrated backplane comprising:

a rear electrode layer provided on the rear surface of the rear electrode layer,

the polymer layer of the polymer is formed of a polymer,

metal foil layer, and

a substrate;

a layer of electrophoretic material disposed adjacent to the integrated backplane;

a light-transmitting electrode layer adjacent to the layer of electrophoretic material; and

pre-integration barrier comprising:

a top protective layer,

moisture barrier, and

an optically clear adhesive, wherein the optically clear adhesive bonds the moisture barrier and the integrated back sheet to create an edge seal.

2. The electrophoretic display of claim 1 wherein the pre-integration barrier deforms at an edge toward the integration back plate to encapsulate the layer of electrophoretic material and the light transmissive electrode layer in a central portion while bonding the vapor barrier and the integration back plate along an edge of the electrophoretic display.

3. The electrophoretic display of claim 1 wherein the pre-integration barrier deforms at an edge toward the integration back plate and the integration back plate deforms at an edge toward the pre-integration barrier to encapsulate the layer of electrophoretic material and the light transmissive electrode layer in a central portion while bonding the moisture barrier and the integration back plate along an edge of the electrophoretic display.

4. An electrophoretic display according to claim 2 or 3, wherein the distance between the edge of the light transmissive electrode layer and the outer edge of the integrated back plate is 1mm or less.

5. The electrophoretic display of claim 4, wherein a distance between an edge of the light-transmissive electrode layer and an outer edge of the integrated back plate is 0.5mm or less.

6. The electrophoretic display of claim 1, further comprising a lamination adhesive layer between the integrated backplane and the layer of electrophoretic material.

7. The electrophoretic display of claim 1, wherein the metal foil is a gold foil, a silver foil, an aluminum foil, or a copper foil.

8. The electrophoretic display of claim 1, wherein the back electrode layer comprises indium tin oxide, conductive carbon, graphene, nanotubes, metal whiskers, or poly (3, 4-ethylenedioxythiophene).

9. The electrophoretic display of claim 1, wherein the electrophoretic material comprises two or more groups of charged particles that move in response to an electric field, wherein each group of charged particles has different optical properties.

10. The electrophoretic display of claim 1, wherein the electrophoretic material comprises three or more groups of charged particles that move in response to an electric field, wherein each group of charged particles has different optical properties.

11. An electrophoretic display, comprising:

post-integration blocking, comprising:

a rear protective layer, and

a rear moisture barrier;

a rear electrode layer;

a layer of electrophoretic material disposed adjacent to the back electrode layer;

a light-transmitting electrode layer adjacent to the electrophoretic material layer at a side opposite to the rear electrode layer; and

pre-integration barrier comprising:

a top protective layer,

front moisture barrier, and

an optically clear adhesive, wherein the optically clear adhesive bonds the front moisture barrier and the back electrode layer to create an edge seal.

12. The electrophoretic display of claim 11 wherein the pre-integration barrier deforms at an edge toward the post-integration barrier to encapsulate the electrophoretic material layer and the light transmissive electrode layer in a central portion while bonding the front moisture barrier and the back electrode layer along an edge of the electrophoretic display.

13. The electrophoretic display of claim 11 wherein the pre-integration barrier deforms at an edge toward the post-integration barrier and the post-integration barrier deforms at an edge toward the pre-integration barrier to encapsulate the layer of electrophoretic material and the light transmissive electrode layer in a central portion while bonding the moisture barrier and the integrated backplate along an edge of the electrophoretic display.

14. An electrophoretic display according to claim 12 or 13, wherein the distance between the edge of the light transmissive electrode layer and the outer edge of the integrated barrier is 1mm or less.

15. The electrophoretic display of claim 14, wherein a distance between an edge of the light transmissive electrode layer and an outer edge of the integrated post-barrier is 0.5mm or less.

16. The electrophoretic display of claim 11, further comprising a lamination adhesive layer between the back electrode layer and the electrophoretic material layer.

17. An electrophoretic display according to claim 11 wherein the back electrode layer is light transmissive.

18. The electrophoretic display of claim 11, wherein the back electrode layer comprises indium tin oxide, conductive carbon, graphene, nanotubes, metal whiskers, or poly (3, 4-ethylenedioxythiophene).

19. The electrophoretic display of claim 11, wherein the electrophoretic material comprises two or more groups of charged particles that move in response to an electric field, wherein each group of charged particles has different optical properties.

20. The electrophoretic display of claim 11, wherein the electrophoretic material comprises three or more groups of charged particles that move in response to an electric field, wherein each group of charged particles has different optical properties.