A color electro-optic display comprising a light fastness additive

Abstract

A color electrophoretic display (100, 200, 300) comprising an electrophoretic medium (122, 222) is disclosed, the electrophoretic medium (122, 222) comprising different types of charged pigment particles (262, 272), at least one of the different types of charged pigment particles being an organic electroactive compound, a lightfastness additive, and a nonpolar liquid. The lightfastness additive is an electron acceptor and it improves the lightfastness of the color electrophoretic display.

Description

(19) State Intellectual Property Office (12) Invention Patent Application (10) Application Publication Number (43) Application Publication Date (21) Application Number 202480062653.4 (22) Application Date 2024.10.23 (30) Priority Data 63 / 546536 2023.10.31 US (85) PCT International Application Entering National Phase Date 2026.03.27 (86) PCT International Application Application Data PCT / US2024 / 052610 2024.10.23 (87) PCT International Application Publication Data WO2025 / 096260 EN 2025.05.08 (71) Applicant: Einker Inc. Address: Massachusetts, USA (72) Inventors: S.J. Telford, R. Casado, S. Yegolov, A.L. Rattus (74) Patent Agency: Beijing Panhua Weiye Intellectual Property Agency Co., Ltd. 11280 Patent Attorney: Guo Guangxun (51) Int.Cl. G02F 1 / 167 (2019.01) G02F 1 / 1675 (2019.01) G02F 1 / 1679 (2019.01) (54) Invention Title: Color Electro-optic Display Containing Lightfast Additives (57) Abstract: This application discloses a color electro-optic display (100, 200, 300) containing an electrophoretic medium (122, 222), the electrophoretic medium (122, 222) comprising different types of charged pigment particles (262, 272), lightfast additives and nonpolar liquids, at least one of the different types of charged pigment particles being an organic electroactive compound. The lightfastness additive is an electron acceptor, and it improves the lightfastness of the color electrophoretic display. Claims 4 pages, Description 19 pages, Drawings 3 pages. CN 122029481 A 2026.05.12 CN 1 22 02 94 81 A 1. A color electro-optic display, comprising, in sequence: a first electrode layer including a light-transmitting electrode; an electro-optic material layer including an electrophoretic medium encapsulated in a plurality of micro-units or microcapsules, the electrophoretic medium containing a plurality of first-type charged pigment particles, a plurality of second-type charged pigment particles, a lightfastness additive, and a non-polar liquid, the lightfastness additive being an electron acceptor and present in the electrophoretic medium at a content of 0.1% to 6.0% by weight; a second electrode layer including a plurality of pixel electrodes. 2. The color electro-optic display of claim 1, wherein the lightfastness additive is selected from substituted 1,4-benzoquinone, substituted 1,2-benzoquinone, substituted naphthoquinone, and substituted anthraquinone, wherein the substituted 1,4-benzoquinone, the substituted 1,2-benzoquinone...The quinone, the substituted naphthoquinone, and the substituted anthraquinone have at least one substituent comprising an alkyl, cycloalkyl, or alkenyl group, and wherein the at least one substituent has 10 to 120 carbon atoms. 3. The color electro-optic display of claim 2, wherein the substituted 1,2-benzoquinone, the substituted 1,4-benzoquinone, the substituted naphthoquinone, and the substituted anthraquinone have at least one substituent represented by formula I or formula II, wherein n is an integer from 2 to 20, and wherein m is an integer from 1 to 20. 4. The color electro-optic display of claim 2, wherein the lightfastness additive is a substituted 1,4-benzoquinone represented by formula III, wherein R1 is represented by formula I or formula II, wherein n is an integer from 2 to 20, and m is an integer from 1 to 20, and wherein R2 to R4 are independently selected from hydrogen, alkyl groups, alkenyl groups, aryl groups, and heteroatom groups containing heteroatoms from groups V-VII of the periodic table. 5. The color electro-optic display of claim 4, wherein R1 is represented by formula II, m is an integer from 2 to 20, and each of R2, R3, and R4 is independently selected from hydrogen, alkyl, alkenyl, and alkoxy groups. (Claims 1 / 4 page 2 CN 122029481 A) 6. The color electro-optic display of claim 5, wherein R2 is a methyl group, and R3 and R4 are methoxy groups. 7. The color electro-optic display of claim 5, wherein R2 is hydrogen, and R3 and R4 are methyl groups. 8. The color electro-optic display of claim 7, wherein the lightfastness additive is represented by formula IV or V. 9. The color electro-optic display of claim 2, wherein the molecular structure of the lightfastness additive is a substituted benzoquinone represented by formula VI, wherein each of R5, R6, and R7 is independently selected from hydrogen, alkyl, alkenyl, and alkoxy groups, and o is an integer from 2 to 20. 10. The color electro-optic display of claim 2, wherein the lightfastness additive is a substituted naphthoquinone, the substituted naphthoquinone being represented by formula VII, wherein each of R8, R9, R10, R11 and R12 may be independently selected from hydrogen, alkyl, alkenyl and alkoxy groups, and wherein p is an integer from 2 to 20. 11. The color electro-optic display of claim 2, wherein the lightfastness additive is a substituted naphthoquinone, the substituted naphthoquinone being represented by formula VIII, wherein each of R13, R14, R15, R16 and R17 may be independently selected from hydrogen, alkyl, alkenyl and alkoxy groups, and wherein q is an integer from 2 to 20. 12. The color electro-optic display of claim 11, wherein the molecular structure of the lightfastness additive is represented by formula VIII, wherein R13, R14, R15, and R16 are hydrogen, and R17 is methyl.13. The color electro-optic display of claim 12, wherein q is selected from 3, 4, 7, and 9. 14. The color electro-optic display of any one of claims 1 to 13, wherein the electrophoretic medium further comprises a plurality of third-type charged pigment particles and a plurality of fourth-type charged pigment particles. 15. The color electro-optic display of claim 14, wherein the first, second, third, and fourth-type charged pigment particles have colors selected from white, black, cyan, magenta, yellow, blue, green, and red. 16. The color electro-optic display of claim 14, wherein the first, second, third, and fourth-type charged pigment particles are white, cyan, magenta, and yellow, respectively. 17. The color electro-optic display of any one of claims 1 to 16, wherein the electro-optic material layer comprises a plurality of microcapsules and an adhesive. 18. The color electro-optic display of claim 17, wherein the color electro-optic display further comprises a first adhesive layer disposed between the electro-optic material layer and the second electrode layer. 19. The color electro-optic display of claim 18, wherein the color electro-optic display further comprises a second adhesive layer, Page 3 / 4 of the claims 4 CN 122029481 A The second adhesive layer is disposed between the electro-optic material layer and the first electrode layer. 20. The color electro-optic display of any one of claims 1 to 16, wherein the electro-optic material layer comprises a plurality of micro-units, each of the plurality of micro-units having a micro-unit bottom, a partition wall, an opening and a sealing layer across the opening, the sealing layer being adjacent to the second electrode layer. Page 4 / 4 of the claims 5 CN 122029481 A Color electro-optic display comprising lightfast additives

[0001] Related Applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 546,536, filed October 31, 2023, which is incorporated herein by reference in its entirety with all other patents and patent applications disclosed herein. Background of the Invention

[0004] The present invention relates to a color electro-optic display comprising an electro-optic material layer having an electrophoretic medium containing a lightfastness additive. The lightfastness additive improves the lightfastness of the color electro-optic display. The electrophoretic medium of the electro-optic material layer of the electro-optic display also contains charged particles in a nonpolar liquid.

[0005] The terms “bistable” and “bistable” are used herein in their conventional meaning in the art to refer to a display comprising display elements having a first display form and a second display form that are different in at least one optical property, and such that either given element is driven to present its first display by an address pulse of finite duration.After the first or second display form, the state will persist for at least several times, for example, at least four times, the minimum duration of the addressing pulse required to change the state of the display element after the addressing pulse has terminated. U.S. Patent No. 7,170,670 shows that some particle-based electrophoretic displays capable of displaying grayscale 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-optic displays. This type of display is aptly referred to as “multistable” rather than bistable, but for convenience, the term “bistable” may be used herein to encompass both bistable and multistable displays.

[0006] When applied to materials or displays, the term “electro-optic” is used herein in its conventional meaning in the field of imaging to refer to a material having a first display state and a second display state that differ in at least one optical property, which is changed from its first display state to its second display state by applying an electric field to the material. Although the optical property is typically color perceptible to the human eye, it can be another optical property, such as transmittance, reflectance, luminescence, or, in the case of a display intended for machine reading, pseudocolor in the sense of a change in reflectance at electromagnetic wavelengths outside the visible light range.

[0007] Some electrophoretic media are solid in the sense that the material has a solid outer surface, although the media may and often do have internal spaces filled with liquid or gas. For convenience, displays using solid electrophoretic media will be referred to below as "solid-state electrophoretic displays".

[0008] Some types of electro-optic displays are known. One type of electro-optic display is the rotating bicolor unit type, as described in, for example, U.S. Patents Nos. 5,808,783; 5,777,782; 5,760,761; 6,054,071; 6,055,091; 6,097,531; 6,128,124; 6,137,467 and 6,147,791 (although this type of display is often referred to as a “rotating bicolor sphere” display, the term “rotating bicolor unit” is preferred because it is more accurate, since in some of the aforementioned patents the rotating unit is not spherical). Such a display uses a large number of small bodies (typically spherical or cylindrical) having two or more portions with different optical properties, as well as internal dipoles. These small bodies are suspended in liquid-filled vesicles within a matrix, allowing the small bodies to rotate freely. By applying an electric field to it, the appearance of the display is altered, thus causing the small body to rotate to different positions and changing the portion of the small body seen through the viewing surface. This type of electro-optic medium is typically bistable. (Instruction manual 1 / 19 pages 6 CN 122029481 A

[0009] )Another type of electro-optic display uses an electrochromic medium, such as an electrochromic medium in the form of a nanochromic film, which comprises an electrode at least partially formed of a semiconductor metal oxide and a plurality of dye molecules capable of reversibly changing color attached to the electrode; see, for example, O'Regan, B. et al., Nature 1991, 353, 737; and Wood, D., Information Display, 18(3), 24 (March 2002). See also Bach, U. et al., Adv. Mater., 2002, 14(11), 845. 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.

[0010] Another type of electro-optic display is the electrowetting 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 electrowetting display can be fabricated to be bistable.

[0011] One class of electro-optic displays that has been a focus of research and development for many years is particle-based electrophoretic displays, in which multiple charged particles move through a liquid under the influence of an electric field. Compared to liquid crystal displays, electrophoretic displays can have properties such as good brightness and contrast, wide viewing angles, bistable states, and low power consumption. However, long-term image quality problems of these displays have hindered their widespread application. For example, the particles constituting an electrophoretic display tend to settle, resulting in a short lifespan for these displays.

[0012] A typical electrophoretic medium in an electrophoretic display contains at least one charge control agent (CCA). The CCA controls the charge on the electrophoretic particles. Typically, CCA is a surfactant-like molecule with ionic or other polar groups (hereinafter referred to as head groups) and a nonpolar chain (usually a hydrocarbon chain, hereinafter referred to as the tail). CCA can recombine with or adsorb onto charged particles. It is believed that CCA forms reverse micelles in electrophoretic media, and it is this small fraction of charged reverse micelles that causes the conductivity of the medium. Reverse micelles contain a polar core, the size of which can vary from 1 nm to tens of nanometers, and can have spherical, cylindrical, or other geometries, surrounded by the nonpolar tail groups of the CCA molecule. In electrophoretic media, three phases can usually be distinguished: a solid particle with a surface, a highly polar phase distributed in the form of tiny droplets (reverse micelles), and a continuous phase containing a nonpolar fluid. When an electric field is applied, both the electrophoretic particles and the charged reverse micelles can move through the fluid, therefore…There are two parallel paths for conducting electricity through the fluid (the fluid itself typically has a small conductivity tending to zero).

[0013] Numerous patents and applications assigned to or attributed to MIT and E Ink Corporation describe various techniques used in encapsulated electrophoretic media and other electrophoretic media. Such encapsulated media contain a number of microcapsules, each microcapsule comprising an inner phase and a capsule wall surrounding the inner phase, the inner phase containing electrophoretically movable particles in a liquid. Typically, the microcapsules themselves are held in a polymer binder to form a coherent layer located between two electrodes. The technologies described in these patents and applications include:

[0014] (a) electrophoretic particles, fluids, and fluid additives; see, for example, U.S. Patents 7,002,728 and 7,679,814;

[0015] (b) microcapsules, adhesives, and encapsulation processes; see, for example, U.S. Patents 6,922,276 and 7,411,719;

[0016] (c) films and subassemblies containing electro-optic materials; see, for example, U.S. Patents 6,982,178 and 7,839,564;

[0017] (d) Backplanes, adhesive layers, and other auxiliary layers and methods used in displays; see, for example, 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;6,967 ,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, Instruction manual 2 / 19 pages 7 CN 122029481 A 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;7,327,511;7,349,148;7,352,353;7,365,394;7,365,733;7,382,363;7, 388,572;7 ,442,587;7 ,492,497;7 ,535,624;7 ,551 ,346;7 ,554 ,712;7 ,583,427;7 ,598, 173; 7,605,799; 7,636,191; 7,649,674; 7,667,886; 7,672,040; 7,688,497; 7,733,335; 7,785,988; 7,843,626; 7,859,637; 7,893,435; 7,898,717; 7,957,053; 7,986,450; 8,009,344; 8,027,081; 8,049,947; 8,077,141; 8,089,453; 8,208,193; 8,373,211; 9,726,957; 10,520 U.S. Patents 786, 10,585,325, and 11,513,414; and U.S. Patents 2002 / 0060321, 2004 / 0105036, 2005 / 0122306, 2005 / 0122563, 2007 / 0052757, 2007 / 0097489, 2007 / 0109219, 2007 / 0211002, 2009 / 0122389, 2009 / 0315044, 2010 / 0265239, 2011 / 0026101, and 2011 / 0140744; U.S. Patent Application Publications Nos. 2011 / 0187683; 2011 / 0187689; 2011 / 0286082; 2011 / 0286086; 2011 / 0292319; 2011 / 0292493; 2011 / 0292494; 2011 / 0297309; 2011 / 0310459; and 2012 / 0182599; and International Application Publication No. WO 00 / 38000; European Patents Nos. 1,099,207 B1 and 1,145,072 B1;

[0018] (e) Color formation and color adjustment; see, for example, U.S. Patent No. 7,075,502 and U.S. Patent Application Publication No. 2007 / 0109219;

[0019] (f) Methods for driving a display; see, for example, 7,012,600; 7,119,772; 7,453,445 and 10,U.S. Patent No. 475,396;

[0020] (g) Applications of the display; see, for example, U.S. Patent Nos. 7,312,784 and 8,009,348; and

[0021] (h) Non-electrophoretic displays, as described in U.S. Patent Nos. 6,241,921; 6,950,220; 7,420,549 and 8,319,759 and U.S. Patent Application Publication No. 2012 / 0293858.

[0022] 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, wherein the electrophoretic medium comprises discrete droplets of multiple electrophoretic media and a continuous phase of polymer material, and recognizes that although the discrete capsules are not associated with each individual droplet, the discrete droplets of electrophoretic media within such a polymer dispersion electrophoretic display can also be considered as capsules or microcapsules; see, for example, U.S. Patent No. 6,866,760 mentioned above. Therefore, for the purposes of this application, such polymer dispersion electrophoretic media are considered a subtype of encapsulated electrophoretic media.

[0023] A related type of electrophoretic display is the so-called “microcell electrophoretic display.” In a microcell electrophoretic display, charged particles and fluid are not encapsulated within microcapsules, but are preserved in multiple cavities formed within a carrier medium, typically a polymer film. See, for example, U.S. Patents 6,672,921 and 6,788,449, both of which have been assigned to Sipix Imaging, Inc.

[0024] Although electrophoretic media are generally opaque (because, for example, in many electrophoretic media, particles essentially block visible light from transmission through the display) and operate in a reflective mode, many electrophoretic displays can be made to operate in so-called “shutter modes,” where one display state is substantially opaque and the other is translucent. See, for example, U.S. Patents 5,872,552; 6,130,774; 6,144,361; 6,172,798; 6,271,823; 6,225,971; and 6,184,856. Dielectric electrophoretic displays, similar to electrophoretic displays but dependent on changes in electric field strength, can operate in a similar mode; see U.S. Patent 4,418,346. Other types of electro-optic displays can also operate in shutter mode. Electrophoretic media operating in shutter mode can be used in multilayer structures for full-color displays; in such structures, at least one layer adjacent to the viewing surface of the display operates in shutter mode to expose or hide a second layer further away from the viewing surface.

[0025] Encapsulated electrophoretic displays generally do not suffer from the aggregation and sedimentation failure modes of conventional electrophoretic displays, and the specification, page 3 / 19, 8 CN 122029481 AIt also provides further advantages, such as the ability to print or coat displays on a variety of flexible and rigid substrates (the term "printing" is intended to include all forms of printing and coating, including but not limited to: volumetric coating, such as patch die coating, slot or extrusion coating, cascade coating, curtain coating; roll coating, such as doctor blade coating, forward and reverse roll coating; gravure coating; dip coating; spray coating; meniscus coating; spin coating; brush coating; air knife coating; screen printing; electrostatic printing; thermal printing; inkjet printing; electrophoretic deposition (see U.S. Patent No. 7,339,715); 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 at low cost.

[0026] Electro-optic displays typically include an electro-optic material layer and at least two other layers disposed on opposite sides of the electro-optic material layer, one of which is an electrode layer. In most such displays, both layers are electrode layers, and one or both electrode layers are patterned to define pixels of the display. For example, one electrode layer may be patterned as an elongated row electrode, and the other electrode layer may be patterned as an elongated column electrode extending at right angles to the row electrode, with pixels defined by the intersection of the row and column electrodes. Alternatively and more commonly, one electrode layer has the form of a single continuous electrode, and the other electrode layer is patterned as a matrix of pixel electrodes, where each pixel electrode defines a pixel of the display. In another type of electro-optic display, intended for use with a stylus, printhead, or similar movable electrodes separate from the display, only one of the layers adjacent to the electro-optic material layer contains electrodes, and the layers on the opposite side of the electro-optic material layer are typically protective layers designed to prevent damage to the electro-optic material layer by the movable electrodes.

[0027] The manufacture of a three-layer electro-optic display typically involves at least one lamination operation. For example, several of the aforementioned MIT and E Ink patents and applications describe methods for manufacturing encapsulated electrophoretic displays, wherein an encapsulated electrophoretic medium is coated onto a flexible substrate, the encapsulated electrophoretic medium comprising microcapsules in an adhesive, the flexible substrate comprising an indium tin oxide (ITO) or similar conductive coating on a plastic film (which serves as an electrode of the final display), and the microcapsule / adhesive coating is dried to form a coherent layer of electrophoretic medium firmly adhered to the substrate. A backplane is prepared separately, the backplane comprising a pixel electrode array and a suitable conductor layout connecting the pixel electrodes to driving circuitry. To form the final display, a substrate with the capsule / adhesive layer on it is laminated to the backplane using a laminating adhesive (a very similar method can be used to...).Electrophoretic displays that can be used with styluses or similar movable electrodes (which can slide on the protective layer) are fabricated by replacing the backplate with a simple protective layer, such as a plastic film. In a preferred form of such a method, the backplate itself is flexible and is fabricated by printing pixel electrodes and conductors onto a plastic film or other flexible substrate. An obvious lamination technique for mass-producing displays using this process is roller lamination using laminating adhesives. Similar manufacturing techniques can also be used for other types of electro-optic displays. For example, microcell electrophoretic media or rotating dual-color cell media can be laminated to the backplate in essentially the same manner as encapsulated electrophoretic media.

[0028] As discussed in the aforementioned U.S. Patent No. 6,982,178 (see column 3, line 63 through column 5, line 46), many components used in solid-state electro-optic displays, as well as methods for manufacturing such displays, are derived from the technology used in liquid crystal displays (LCDs), which are also electro-optic displays, except that they use a liquid medium instead of a solid medium. For example, a solid-state electro-optic display can utilize an active matrix backplane comprising an array of transistors or diodes and corresponding pixel electrode arrays, and a “continuous” front electrode on a transparent substrate (in the sense of electrodes extending across multiple pixels and typically the entire display). These components are essentially the same as those in an LCD. However, the methods used to assemble LCDs cannot be used for solid-state electro-optic displays. LCDs are typically assembled by forming a backplane and front electrode on separate glass substrates, then bonding these components together with a small hole between them, placing the resulting assembly in a vacuum, and immersing the assembly in a liquid crystal bath so that liquid crystal flows through the hole between the backplane and front electrode. Finally, with the liquid crystal in place, the hole is sealed to provide the final display.

[0029] This LCD assembly process cannot be easily transferred to solid-state electro-optic displays. Because the electro-optic material layer is solid, it must exist between the backplane and the front electrode before they are fixed together. Furthermore, unlike liquid crystal materials, which are simply placed between the front electrode and the backplate without being bonded to either, solid-state electro-optic material layers typically need to be fixed to both. In most cases, the solid-state electro-optic material layer is formed on the front electrode, as this is generally easier than forming the dielectric on the backplate containing the circuitry. The front electrode / electro-optic material layer combination is then laminated onto the backplate, usually by covering the entire surface of the electro-optic material layer with adhesive and laminating under heat, pressure, and possibly vacuum. Therefore, most prior art methods for final lamination of solid-state electrophoretic displays are essentially batch processes, where the electro-optic material layer, laminating adhesive, and backplate are (typically) placed together immediately before final assembly, and require the provision of...A method better suited for mass production.

[0030] The aforementioned U.S. Patent No. 6,982,178 describes a method for assembling a solid-state electro-optic display (including an encapsulated electrophoretic display) that is well-suited for mass production. Essentially, the patent describes a so-called “front panel laminate” (“FPL”) comprising, in sequence: a light-transmitting conductive layer; an electro-optic material layer in electrical contact with the conductive layer; an adhesive layer; and a release sheet. Typically, the light-transmitting conductive layer is carried on a light-transmitting substrate, which is preferably flexible, meaning that the substrate can be manually wound around a roller with a diameter of (approximately) 10 inches (254 mm) without permanent deformation. The term "transparent" is used in this patent and herein to refer to a layer so defined that it transmits sufficient light to allow an observer to view through it to observe changes in the display state of the electrophoretic medium, typically through the conductive layer and an adjacent substrate (if present); where the electrophoretic medium exhibits a change in reflectivity at non-visible wavelengths, the term "transparent" should of course be interpreted as transmission at the relevant non-visible wavelength. The substrate is generally a polymer film and typically has 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 preferably a thin metal or metal oxide layer, such as an aluminum or ITO layer, or it may be a conductive polymer. Poly(ethylene terephthalate) (PET) films coated with aluminum or ITO are commercially available, for example, from E.I. du Pont de Nemours & Company of Wilmington, Delaware, under the name "aluminized Mylar" ("Mylar" is a registered trademark), and such commercial materials can be used for front panel laminates with good results.

[0031] Assembling an electro-optic display using such a front panel laminate can be achieved by removing the release sheet from the front panel laminate and contacting the adhesive layer with the back panel under conditions that effectively adhere the adhesive layer to the back panel, thereby fixing the adhesive layer, electrophoretic dielectric layer, and conductive layer to the back panel. This process is well-suited for mass production because the front panel laminate can be mass-produced, generally using roll-to-roll coating technology, and then cut into sheets of any size required for use with a particular back panel.

[0032] U.S. Patent No. 7,561,324 describes a so-called "dual release sheet," which is essentially a simplified version of the front-panel laminate of the aforementioned U.S. Patent No. 6,982,178. One form of the dual release sheet includes a solid electro-optic material layer sandwiched between two adhesive layers, wherein one or both adhesive layers are covered by the release sheet. Another form of the dual release sheet includes a solid electro-optic material layer sandwiched between two release sheets. Both forms of dual release films are intended for use in such...The process, generally similar to that used for assembling an electro-optic display from a front panel laminate already described, but involving two separate laminations; typically, in the first lamination, a double release liner is laminated to the front electrode to form a front sub-assembly, and then in the second lamination, the front sub-assembly is laminated to the back panel to form the final display, but the order of these two laminations can be reversed if desired.

[0033] U.S. Patent No. 7,839,564 describes a so-called “inverted front panel laminate,” a variation of the front panel laminate described in U.S. Patent No. 6,982,178 above. The inverted front panel laminate sequentially comprises at least one of: a light-transmitting protective layer (see specification 5 / 19 pages 10 CN 122029481 A) and a light-transmitting conductive layer; an adhesive layer; a solid electro-optic material layer; and a release liner. The inverted front plate laminate is used to form an electro-optic display having a laminated adhesive layer between an electro-optic material layer and a front electrode or front substrate; a second, generally thin adhesive layer may or may not be present between the electro-optic material layer and the back plate. Such an electro-optic display can combine good resolution with good low-temperature performance.

[0034] In a high-resolution display, each individual pixel must be addressable without interference from addressing of adjacent pixels (regardless of whether the electrophoretic medium used is bistable). One way to achieve this is to provide an array of nonlinear elements, such as an array of transistors or diodes, wherein at least one nonlinear element is associated with each pixel to produce an active matrix display, as mentioned above. An addressing (pixel) electrode is connected to a suitable voltage source via its associated nonlinear element, the addressing (pixel) electrode addressing a pixel. By convention, in high-resolution arrays, pixels are arranged in a two-dimensional array of rows and columns such that any particular pixel is uniquely defined by the intersection of a specified row and a specified column. The sources of all transistors in each column are connected to a single column electrode, while the gates of all transistors in each row are connected to a single row electrode; the source-to-row and gate-to-column assignments are conventional and can be reversed if desired. The row electrodes are connected to a row driver, which essentially ensures that only one row is selected at any given time—that is, a voltage is applied to the selected row electrode to ensure that all transistors in the selected row are conductive, while voltages are applied to all other rows to ensure that all transistors in these unselected rows remain non-conductive. The column electrodes are connected to a column driver, which applies a selected voltage to each column electrode to drive the pixels in the selected row to their desired optical state. The aforementioned voltages are relative to a common front electrode, which is typically positioned on the side of the electrophoretic medium opposite the nonlinear array and extends across the entire display. After a preselection interval known as the “line addressing time,” the selected row is deselected, and the next row…The column driver is selected, and the voltage changes, causing the next row of the display to be written. This process is repeated, causing the entire display to be written row by row.

[0035] In the following discussion, the term “waveform” will be used to refer to a curve of the entire voltage changing over time, which affects the transition of a pixel from a particular initial gray level to a particular final gray level. Typically, such a waveform contains multiple waveform elements; wherein these elements are essentially rectangular (i.e., wherein a given element contains the application of a constant voltage for a period of time); said elements may be referred to as “pulses” or “drive pulses”. The term “drive scheme” refers to a set of waveforms sufficient to affect the possible transitions between all gray levels of a particular display. A display may use multiple drive schemes; for example, U.S. Patent No. 7,012,600 teaches that a drive scheme may need to be modified according to parameters such as the temperature of the display or the time it has been running during its lifespan, and thus, a display may be equipped with multiple different drive schemes for use under conditions such as different temperatures. A set of drive schemes used in this way may be referred to as a “set of related drive schemes”.

[0036] Electro-optic displays comprising electrophoretic media having black and white particles are well known in the art and have been used in e-readers, electronic notebooks, and other devices for over a decade. Typically, the black and white particles comprise inorganic pigments. More recently, electro-optic displays comprising electrophoretic media having colored particles, such as yellow, red, and other colored particles, have been introduced to the market. Typically, such electro-optic displays comprise colored particles containing organic pigments in addition to white particles and optionally black particles. For color displays, organic pigments are superior to inorganic pigments because they provide more vibrant colors and significantly higher chromaticity. However, in the presence of ultraviolet and visible light, organic pigments generally exhibit lower long-term color stability than inorganic pigments. Therefore, there is a need to develop color electro-optic displays comprising electrophoretic media containing organic pigments, wherein the color quality of the electro-optic display image remains stable even after prolonged use of the display. The inventors of the present invention have surprisingly discovered that color electro-optic devices comprising electrophoretic media containing organic pigments and electron acceptor molecules significantly improve the long-term color quality of electro-optic display images. Specification 6 / 19 pages 11 CN 122029481 A Summary of the Invention

[0038] Therefore, the present invention provides a color electro-optic display, which sequentially includes a first electrode layer, an electro-optic material layer, and a second electrode layer. The first electrode layer includes a light-transmitting electrode. The second electrode layer includes a plurality of pixel electrodes. The electro-optic material layer includes an electrophoretic medium, which is encapsulated in a plurality of microunits or a plurality of microcapsules. The electrophoretic medium includes a plurality of first-type charged pigment particles, a plurality of second-type charged pigment particles, lightfast additives, and a non-polar liquid.The charged pigment particles of the first and second types contain at least one organic pigment. The lightfastness additive is present in the electrophoretic medium at a content of 0.1% to 6.0% by weight, based on the weight of the electrophoretic medium.

[0039] The electro-optic material layer may include a plurality of microcapsules and an adhesive, each microcapsule containing the electrophoretic medium. The color electro-optic display containing the electrophoretic medium encapsulated in a plurality of microcapsules may further include a first adhesive layer disposed between the electro-optic material layer and the second electrode layer. In addition to the first adhesive layer, the color electro-optic display containing the electrophoretic medium encapsulated in a plurality of microcapsules may further include a second adhesive layer disposed between the electro-optic material layer and the first electrode layer.

[0040] The electro-optic material layer may include a plurality of microunits. Each of the plurality of microunits may have a microunit bottom, a partition wall, an opening, and a sealing layer across the opening. The sealing layer may be adjacent to the second electrode layer. Each microunit is filled with an electrophoretic medium. The color electro-optic display having multiple micro-units in the electro-optic material layer may further include an adhesive layer disposed between the sealing layer and the second electrode layer.

[0041] In addition to the plurality of charged pigment particles of the first and second types, the electrophoretic medium of the color electro-optic display of the present invention may also include a plurality of charged pigment particles of the third type. The pigment particles of the first, second, and third types may have different colors selected from white, black, cyan, magenta, yellow, blue, green, and red. The pigment particles of the first, second, and third types may be (a) white, (b) black, and (c) yellow or red, respectively.

[0042] In addition to the plurality of charged pigment particles of the first, second, and third types, the electrophoretic medium of the color electro-optic display of the present invention may also include a plurality of charged pigment particles of the fourth type. The pigment particles of the first, second, third, and fourth types may have different colors selected from white, black, cyan, magenta, yellow, blue, green, and red. The pigment particles of the first, second, third, and fourth types may be white, cyan, magenta, and yellow, respectively. The pigment particles of the first, second, third, and fourth types can be white, blue, red, and green, respectively.

[0043] In addition to the plurality of charged pigment particles of the first, second, third, and fourth types, the electrophoretic medium of the color electro-optic display of the present invention may also contain a plurality of charged pigment particles of the fifth type. The charged pigment particles of the first, second, third, fourth, and fifth types can have different colors selected from white, black, cyan, magenta, yellow, blue, green, and red. The pigment particles of the first, second, third, fourth, and fifth types can be white, black, red, blue, and green, respectively.

[0044] The lightfastness additives in the electrophoretic medium of the color electro-optic display of the present invention improve the lightfastness of the display.The lightfastness additive is an electron acceptor. The lightfastness additive may be selected from substituted 1,2-benzoquinone, substituted 1,4-benzoquinone, substituted naphthoquinone, and substituted anthraquinone. The substituted 1,2-benzoquinone, substituted 1,4-benzoquinone, substituted naphthoquinone, and substituted anthraquinone may have at least one substituent comprising an alkyl, cycloalkyl, or alkenyl group. The at least one substituent may have 10 or more carbon atoms. The at least one substituent may have 10 to 120 carbon atoms.

[0045] The substituted 1,2-benzoquinone, substituted 1,4-benzoquinone, substituted naphthoquinone, and substituted anthraquinone may have at least one substituent, which is represented by Formula I or Formula II, where n is an integer from 2 to 20, and where m is an integer from 1 to 20. Specification 7 / 19 pages 12 CN 122029481 A

[0046]

[0047] The lightfastness additive of the electrophoretic medium may be a substituted 1,4-benzoquinone, which is represented by Formula III.

[0048]

[0049] R1 may be represented by Formula I or Formula II, wherein n may be an integer from 2 to 20, and m may be an integer from 1 to 20, or from 2 to 13. R2 to R4 may be independently selected from hydrogen, alkyl groups, alkenyl groups, aryl groups, and heteroatom groups containing heteroatoms of Groups V-VII of the periodic table.

[0050] The lightfastness additive of the electrophoretic medium may be represented by Formula III, wherein R1 may be represented by Formula II, m may be an integer from 2 to 20, and wherein each of R2, R3, and R4 may be independently selected from hydrogen, alkyl, alkenyl, and alkoxy groups.

[0051] The lightfastness additive of the electrophoretic medium can be represented by Formula III, wherein R1 can be represented by Formula II, m is an integer from 2 to 20, wherein R2 can be methyl, and wherein R3 and R4 can be methoxy groups.

[0052] The lightfastness additive of the electrophoretic medium can be represented by Formula III, wherein R1 can be represented by Formula II, m is an integer from 2 to 20, wherein R2 can be hydrogen, and R3 and R4 can be methyl groups.

[0053] The lightfastness additive can be a substituted 1,4-benzoquinone represented by Formula IV.

[0054] .

[0055] The lightfastness additive can be a substituted 1,4-benzoquinone (ubiquinone-10) represented by Formula V. Specification 8 / 19 pages 13 CN 122029481 A

[0056] .

[0057] The lightfastness additive of the electrophoretic medium may be a substituted 1,4-benzoquinone, represented by formula VI. Each of R5, R6, and R7 may be independently selected from hydrogen, alkyl, alkenyl, and alkoxy groups. In formula VI, o is an integer from 2 to 20.

[0058] .

[0059] The lightfastness additive of the electrophoretic medium may be a substituted naphthoquinone, represented by formula VII.Each of R8, R9, R10, R11, and R12 is independently selected from hydrogen, alkyl, alkenyl, and alkoxy groups. In Formula VII, p is an integer from 2 to 20.

[0060] .

[0061] The lightfastness additive of the electrophoretic medium may be a substituted naphthoquinone, which is represented by Formula VIII. Each of R13, R14, R15, R16, and R17 may be independently selected from hydrogen, alkyl, alkenyl, and alkoxy groups. In Formula VIII, q is an integer from 2 to 20. The integer p in Formula VIII may be selected from 3, 4, 7, and 9.

[0062] In the example of the lightfastness additive represented by Formula VIII, R13, R14, R15, R16, and R17 may be hydrogen, and R21 is methyl. The integer q in the example may be 3, 4, 7, or 9.

[0063] . Specification 9 / 19 Page 14 CN 122029481 A Brief Description of the Drawings

[0065] FIG1 is a side view of a color electro-optic display containing an electrophoretic medium encapsulated in microcapsules. The color electrophoretic display sequentially includes: a first electrode layer, an electro-optic material layer, a first adhesive layer, and a second electrode layer.

[0066] FIG2 is a side view of a color electro-optic display containing an electrophoretic medium encapsulated in microcapsules. The color electrophoretic display sequentially includes: a first electrode layer, a second adhesive layer, an electro-optic material layer, a first adhesive layer, and a second electrode layer.

[0067] FIG3 is a side view of a color electro-optic display containing an electrophoretic medium encapsulated in microcells. The color electrophoretic display sequentially includes: a first electrode layer, an electro-optic material layer including a sealing layer, a first adhesive layer, and a second electrode layer.

[0068] FIG4, 5, and 6 are micrographs of microcapsules containing electro-optic material layers for three different electrophoretic media. Detailed Description of the Invention

[0070] As used herein, the term “electron acceptor” or its synonym “electron acceptor molecule” refers to a compound that accepts an electron from another molecule, which is an electron donor. That is, the electron acceptor can be an oxidizing agent.

[0071] The terms “substituted 1,2-benzoquinone,” “substituted 1,4-benzoquinone,” “substituted naphthoquinone,” and “substituted anthraquinone” are molecules whose molecular structure comprises a 1,2-benzoquinone, 1,4-benzoquinone, naphthoquinone, and anthraquinone ring structure and at least one substituent directly attached to the 1,2-benzoquinone, 1,4-benzoquinone, naphthoquinone, and anthraquinone ring structure.

[0072] As used herein, the term “alkyl” refers to a hydrocarbon group that can be linear or branched. The hydrocarbon group contains a carbon-carbon single bond. The hydrocarbon group does not contain a carbon-carbon double bond or a carbon-carbon triple bond.

[0073] As used herein, the term “cycloalkyl” refers to a saturated hydrocarbon containing a ring structure. The saturated hydrocarbon can contain monocyclic, bicyclic, tricyclic, or other polycyclic hydrocarbon groups. The carbon atoms in the ring structure may contain substituents, which may be linear or branched.

[0074] As used herein, the term "alkenyl" refers to a hydrocarbon group having at least one carbon-carbon double bond. The hydrocarbon group may be linear or branched.

[0075] As used herein, the term "aryl" refers to a hydrocarbon group containing an aromatic ring.

[0076] As used herein, the term "heteroatomic group" refers to an alkyl, cycloalkyl, alkenyl, or aryl group containing at least one heteroatom from Groups V-VII of the periodic table in addition to carbon and hydrogen atoms.

[0077] As used herein, the term "aliphatic hydrocarbon" includes saturated and unsaturated, non-aromatic, linear (i.e., straight-chain), branched, acyclic, and cyclic hydrocarbons.

[0078] A compound is "soluble" in a liquid if at least 1 gram of the compound can dissolve in 100 grams of liquid.

[0079] The term "lightfastness" relating to color electro-optic displays relates to the consistency of the color quality of a color electro-optic display image over time. Over time, the color quality of a color electro-optic display image deteriorates, meaning that the total color gamut that the color electro-optic display can provide decreases.

[0080] A typical color electro-optic display may have an electro-optic material layer comprising an electrophoretic medium encapsulated in microcapsules or microcells, as described in U.S. Patent No. 6,982,178. FIG1 shows a side view of a basic structural example of a portion of a color electro-optic display having microcapsules. The color electro-optic display 100 includes a first electrode layer 101 comprising light-transmitting electrodes, an electro-optic material layer 102, a first adhesive layer 104, and a second electrode layer 103, the second electrode layer comprising a plurality of pixel electrodes. The first adhesive layer 104 connects the electro-optic material layer 102 to the second electrode layer. The electro-optic material layer 102 comprises a plurality of microcapsules 112. Each microcapsule has a microcapsule wall and contains an electrophoretic medium 122 having charged pigment particles in a nonpolar liquid. The electrophoretic medium 122 comprises a plurality of first-type charged pigment particles and a plurality of second-type pigment particles. At least one of the first and second-type charged pigment particles comprises an organic pigment. The electrophoretic medium may also contain multiple charged pigment particles of type 3 (see page 10 / 19 of CN 122029481 A). The electrophoretic medium 122 may also contain multiple charged pigment particles of type 4. The electrophoretic medium 122 may also contain multiple charged pigment particles of type 5. The electrophoretic medium 122 also contains lightfastness additives. Typically, multiple microcapsules are contained within a polymer binder 132. A viewer can view the image of the display 100 from the viewing side 150. At least one type of charged pigment may contain organic pigments. The colored electro-optic material layer 100 may be constructed from a front-plate laminate as described in the background of the invention.

[0081] Another example of a colored electro-optic display is shown in FIG. 2. FIG. 2 illustrates a colored electro-optic display with microcapsules.A side view of a basic structural example of a portion. The electro-optic display 200 has a viewing side 150. It sequentially includes: a first electrode layer 101 containing light-transmitting electrodes, a second adhesive layer 105, an electro-optic material layer 102, a first adhesive layer 104, and a second electrode layer 103 containing a plurality of pixel electrodes. The second adhesive layer 105 connects the first electrode layer 101 to the electro-optic material layer 102. The first adhesive layer 104 connects the electro-optic material layer 102 to the second electrode layer. The electro-optic material layer 102 contains a plurality of microcapsules 112. Each microcapsule has a microcapsule wall and contains an electrophoretic medium 122 having charged pigment particles in a non-polar liquid. The electrophoretic medium 122 contains a plurality of first-type charged pigment particles and a plurality of second-type charged pigment particles. At least one of the first and second-type charged pigment particles contains an organic pigment. The electrophoretic medium may also contain a plurality of third-type charged pigment particles. The electrophoretic medium 122 may also contain a plurality of fourth-type charged pigment particles. Electrophoretic medium 122 may also contain a plurality of fifth-type charged pigment particles. Electrophoretic medium 122 also contains lightfastness additives. Typically, a plurality of microcapsules are contained within polymer adhesive 132. Color electro-optic material layer 100 may be constructed from a dual release sheet as described in the background of the invention.

[0082] The microcapsule color electro-optic display of Figures 1 and 2 may also include a light-transmitting front substrate (not shown in Figures 1 and 2) adjacent to a first electrode layer 101, wherein the electrode layer is disposed between the front substrate and the electro-optic material layer (for the display of Figure 1) or between the front substrate and the second adhesive layer (for the display of Figure 1). The front substrate may be a plastic film, such as a poly(ethylene terephthalate) (PET) sheet having a thickness of 25 to 200 µm. The front substrate may also include one or more additional layers, such as a protective layer for absorbing ultraviolet radiation, a barrier layer for preventing oxygen or moisture from entering the display, and an anti-reflective coating for improving the optical properties of the display.

[0083] An example of a color electro-optic display containing microcells is shown in Figure 3. The color electro-optic display 300 in Figure 3 sequentially includes: a first electrode layer 201, an electro-optic material layer 202, an adhesive layer 204, and a second electrode layer 203 containing multiple pixel electrodes. The adhesive layer 204 connects the sealing layer 232 of the electro-optic material layer 202 to the second electrode layer 203. The electro-optic material layer 202 of the color electro-optic display 300 includes multiple microcells 212 and a sealing layer 232. Each microcell 212 has a bottom 242, a partition wall 252, and an opening, and the sealing layer 232 spans the opening of each microcell. Each microcell 212 includes an electrophoretic medium 222. The electrophoretic medium 222 contains multiple first-type charged pigment particles 272 and multiple second-type charged pigment particles 262 in a non-polar liquid. The first-type and second-type charged pigment particles (272 and...)At least one of 262) contains an organic pigment. Electrophoretic medium 222 may also contain a plurality of third-type charged pigment particles. Electrophoretic medium 222 may also contain a plurality of fourth-type charged pigment particles. Electrophoretic medium 222 may also contain a plurality of fifth-type charged pigment particles. Electrophoretic medium 222 also contains lightfastness additives. A viewer can view the image of display 100 from viewing side 250.

[0084] The micro-unit color electro-optic display of FIG3 may also include a light-transmitting front substrate (not shown in FIG3) adjacent to a first electrode layer 201, wherein the electrode layer is disposed between the front substrate and the electro-optic material layer. The front substrate may be a plastic film, such as a poly(ethylene terephthalate) (PET) sheet having a thickness of 25 to 200 µm. The front substrate may also include one or more additional layers, such as a protective layer for absorbing ultraviolet radiation, a barrier layer for preventing oxygen or moisture from entering the display, and an anti-reflective coating for improving the optical properties of the display. Specification 11 / 19 pages 16 CN 122029481 A

[0085] In the electro-optic displays of Figures 1, 2 and 3, the first electrode layer may be a conductive layer having a thin, continuous coating of conductive material with minimal inherent absorption of electromagnetic radiation in the visible spectrum, such as indium tin oxide (ITO), poly(3,4-ethylenedioxythiophene)poly(styrene sulfonate) (PEDOT:PSS), graphene or the like.

[0086] Microcells may be formed by batch processes or continuous roll-to-roll processes as disclosed in U.S. Patent No. 6,933,098. The latter provides a continuous, low-cost, high-throughput manufacturing technique for producing compartments for a variety of applications, including electro-optic display devices. Microcell arrays suitable for use in the present invention may be manufactured using micro-embossing.

[0087] The electrophoretic medium of the color electro-optic display of the present invention comprises charged pigment particles, lightfast additives and a nonpolar liquid. The nonpolar liquid may include aliphatic hydrocarbons. The lightfastness additive is an electron acceptor. The lightfastness additive is present in the electrophoresis medium at a content of 0.1 to 6.0% by weight, based on the weight of the electrophoresis medium. The lightfastness additive may be present in the electrophoresis medium at a content of 0.2 to 5.0%, 0.4 to 4.0%, 0.5 to 3.0%, 0.6 to 2.0%, or 0.7 to 1.5% by weight, based on the weight of the electrophoresis medium. The lightfastness additive is soluble in the nonpolar liquid of the electrophoresis medium. The lightfastness additive is soluble in the electrophoresis medium.

[0088] The lightfastness additive may be selected from substituted 1,2-benzoquinone, substituted 1,4-benzoquinone, substituted naphthoquinone, and substituted...Anthraquinones. The substituted 1,2-benzoquinone, substituted 1,4-benzoquinone, substituted naphthoquinone, and substituted anthraquinone may have at least one substituent comprising an alkyl, cycloalkyl, or alkenyl group. The at least one substituent may have 8 or more carbon atoms, 10 or more carbon atoms, 12 or more carbon atoms, 15 or more carbon atoms, 20 or more carbon atoms, 25 or more carbon atoms, 30 or more carbon atoms, 35 or more carbon atoms, 40 or more carbon atoms, 60 or more carbon atoms, 80 or more carbon atoms, 100 or more carbon atoms, or 110 or more carbon atoms.

[0089] The at least one substituent may have 8 to 120 carbon atoms, 10 to 120 carbon atoms, 12 to 110 carbon atoms, 15 to 110 carbon atoms, 20 to 110 carbon atoms, 25 to 110 carbon atoms, 30 to 110 carbon atoms, or 40 to 110 carbon atoms. The at least one substituent may have 8 to 105 carbon atoms, 10 to 100 carbon atoms, 12 to 90 carbon atoms, 15 to 90 carbon atoms, 20 to 85 carbon atoms, 25 to 80 carbon atoms, 30 to 85 carbon atoms, or 40 to 85 carbon atoms.

[0090] The lightfastness additive may be a substituted 1,2-benzoquinone, a substituted 1,4-benzoquinone, a substituted naphthoquinone, or a substituted anthraquinone having at least one substituent, wherein the at least one substituent is represented by Formula I or Formula II, wherein n is an integer from 2 to 20, and m is an integer from 1 to 20.

[0091] .

[0092] The lightfastness additive may be a substituted 1,4-benzoquinone, wherein the substituted 1,4-benzoquinone is represented by Formula III, and R1 in the specification 12 / 19 pages 17 CN 122029481 A is represented by Formula I or Formula II, wherein n is an integer from 2 to 20, and m is an integer from 1 to 20. The integer n may be 1 to 20, 2 to 18, 2 to 15, 3 to 12, or 3 to 10. The integer m can be 1 to 20, 1 to 18, 2 to 18, 2 to 15, 3 to 15, 3 to 12, 3 to 10, or 4 to 10. Substituent R1 can also be an alkyl group containing 10 to 100 carbon atoms, 10 to 80 carbon atoms, 10 to 70 carbon atoms, 10 to 50 carbon atoms, 10 to 30 carbon atoms, 10 to 20 carbon atoms, or 10 to 15 carbon atoms. Substituents R2 to R4 can be independently selected from hydrogen, alkyl groups, alkenyl groups, aryl groups, and heteroatom groups containing heteroatoms from groups V-VII of the periodic table. The heteroatoms can be selected from nitrogen, oxygen, halogen, phosphorus, or sulfur.

[0093]

[0094] The lightfastness additive can be 1,4-benzoquinone represented by Formula III, with substituent R1 represented by Formula II, and the integer m...The number of R2, R3, and R4 is 2 to 20, and each of R2, R3, and R4 is independently selected from hydrogen, alkyl, alkenyl, and alkoxy groups. The lightfastness additive can be 1,4-benzoquinone represented by Formula III, with substituent R1 represented by Formula II, integer m being 2 to 20, R2 being hydrogen, and R3 and R4 being methyl groups.

[0095] The lightfastness additive can be 1,4-benzoquinone represented by Formula III, with substituent R1 represented by Formula II, m being 9, R2 being hydrogen, and R3 and R4 being methyl groups. The molecular structure of the lightfastness additive is represented by Formula IV.

[0096] .

[0097] The lightfastness additive can be 1,4-benzoquinone represented by Formula III, with substituent R1 represented by Formula II, m being 10, R2 being methyl groups, and R3 and R4 being methoxy groups. The molecular structure of the lightfastness additive is represented by Formula V. Formula V is referred to in the literature as ubiquinone-10.

[0098] .

[0099] The lightfastness additive may be 1,4-benzoquinone represented by Formula III, wherein substituent R1 may be represented by Formula II, m is 2, R2 is a methyl group, and R3 and R4 are methoxy groups.

[0100] The lightfastness additive may be 1,4-benzoquinone represented by Formula VI, wherein each of R5, R6 and R7 may be independently selected from hydrogen, alkyl, alkenyl and alkoxy groups, and wherein o is an integer from 2 to 20.

[0101] .

[0102] The lightfastness additive may be a substituted naphthoquinone represented by Formula VII, wherein each of R8, R9, R10, R11 and R12 may be independently selected from hydrogen, alkyl, alkenyl and alkoxy groups, and wherein p is an integer from 2 to 20.

[0103] .

[0104] The lightfastness additive may be a substituted naphthoquinone represented by formula VIII, wherein each of R13, R14, R15, R16 and R17 may be independently selected from hydrogen, alkyl, alkenyl and alkoxy groups, and wherein q is an integer from 2 to 20.

[0105] .

[0106] The lightfastness additive may be a substituted naphthoquinone represented by formula VIII, wherein q is an integer from 2 to 20, wherein R13, R14, R15, R16 are hydrogen, and R17 is methyl. The integer q may be selected from 3, 4, 7 and 9.

[0107] The electrophoretic medium of the innovative color electro-optic display of the present invention comprises two or more types of charged pigment particles. The electrophoretic medium of the innovative color electro-optic display of the present invention comprises a plurality of first type charged pigment particles and a plurality of second type charged pigment particles. The first type charged pigment particles have a different color than the second type charged pigment particles. At least one of the first and second charged pigment particles comprises an organic pigment. The color electro-optic display of the present inventionThe electrophoretic medium may also contain a plurality of third-type charged pigment particles, which may have a different color from the first and second charged pigment particles. The third charged pigment particles may include organic pigments. The electrophoretic medium of the color electro-optic display of the present invention may also contain a plurality of fourth-type charged pigment particles, which may have a different color from the first, second and third charged pigment particles. The third charged pigment particles may include organic pigments. The electrophoretic medium of the color electro-optic display of the present invention may also contain a plurality of fifth-type charged pigment particles, which may have a different color from the first, second, third and fourth charged pigment particles. The fifth charged pigment particles may include organic pigments. Specification 14 / 19 pages 19 CN 122029481 A

[0108] Each type of charged pigment particle in the electrophoretic medium may carry a positive charge or a negative charge. If the electrophoretic medium contains two types of charged pigment particles, namely the first and second types of charged pigment particles, the first type of charged pigment particles may carry a negative charge (or a positive charge), and the second type of charged pigment particles may carry a positive charge (or a negative charge). When an electric field is applied across the electro-optic material layer through the pixel electrode of the transparent conductive layer and the backplate, charged pigment particles of the first type in the electrophoretic medium move toward the positive electrode and charged pigment particles of the second type move toward the negative electrode, so that an observer viewing the display from the viewing side sees either the charged pigment particles of the first type or the charged pigment particles of the second type corresponding to the pixel electrode, depending on whether the transparent conductive layer is positively or negatively charged relative to the pixel electrode.

[0109] In one example, the electrophoretic medium contains three types of charged pigment particles, each having a different color from the other types. Two of the three types of charged pigment particles may be positively charged, and one type of charged pigment particle is negatively charged. At least one of the types of charged pigment particles contains an organic pigment. Two of the types of charged pigment particles may contain organic pigments. The colors of the three types of charged pigment particles may be selected from white, black, yellow, red, blue, cyan, and magenta.

[0110] In another example, the electrophoretic medium contains four types of charged pigment particles. Each type of charged pigment particle may have a different color. Two of the charged pigment particles of this type can carry a positive charge, and two of the charged pigment particles of this type can carry a negative charge. Alternatively, three of the charged pigment particles of this type can carry a positive charge, and one type of charged pigment particle can carry a negative charge. At least one of the charged pigment particles of this type contains an organic pigment. Two types of charged pigment particles may contain organic pigments. The colors of the four types of charged pigment particles can be selected from white, black, yellow, red, blue, cyan, and magenta. For example, electrophoretic particles may contain white...The five types of charged pigment particles are white, black, green, yellow, red, blue, cyan, green, and yellow. Cyan, magenta, and yellow charged particles may carry a positive charge, and white charged particles may carry a negative charge.

[0111] In another example, the electrophoretic medium comprises five types of charged pigment particles. Each type of charged pigment particle may have a different color. Three of the charged pigment particles of said type may carry a positive charge, and two of said type may carry a negative charge. Alternatively, four of said type of charged pigment particles may carry a positive charge, and one type of charged pigment particle may carry a negative charge. At least one of said type of charged pigment particles contains an organic pigment. Two, three, or four types of charged pigment particles may contain organic pigments. The colors of the five types of charged pigment particles may be selected from white, black, green, yellow, red, blue, cyan, green, and magenta. For example, the electrophoretic particles may contain white, cyan, magenta, and yellow. Cyan, magenta, and yellow charged pigment particles may carry a positive charge, and white charged particles may carry a negative charge.

[0112] As mentioned above, organic pigments generally have lower long-term color stability than inorganic pigments. However, in terms of color, organic pigments are much more desirable because they exhibit much brighter and more saturated colors than inorganic pigments. That is, the color of organic pigments is less stable over time when exposed to ultraviolet or visible light. The lightfastness additives in the color electrophoretic medium of the color electro-optic display of the present invention significantly improve the lightfastness of the electro-optic display of the present invention.

[0113] Although the mechanism by which the color quality of the image of the color electro-optic display deteriorates during long-term exposure to light is not fully understood, the inventors of the present invention have observed that the addition of electron donor molecules such as amines to the electrophoretic medium composition reduces the lightfastness of the color electro-optic display. Uncontrolled trace amounts of electron donor molecules are likely to be present in the materials used to prepare the electrophoretic composition. For example, charge control agents (CCAs) are surfactant-type molecules, typically quaternary ammonium salts, which are prepared by reacting an amine with a suitable alkylating agent. Incomplete alkylation results in the presence of some free amine, which, as mentioned above, is an electron donor. Because alkylating agents are toxic compounds, manufacturers of quaternary ammonium salts typically reduce their addition slightly for safety reasons. As a result, many commercially available or custom-made CCA molecules contain small amounts of free amine.

[0114] An example of an electron donor is panthenol-10, which is the fully reduced form of ubiquinone-10 (as shown above, Formula V). The inventors of this invention have found that the addition of panthenol-10 (an electron donor molecule) to the electrophoretic medium of a color electro-optic display has a detrimental effect on the lightfastness of the color electro-optic display. Conversely, the inventors of this invention have found that electron acceptor molecules, such as ubiquinone-10, have a beneficial effect on the lightfastness of color electro-optic displays. Electron acceptors evaluated for lightfastness additives...One example is ubiquinone-10 (also known as coenzyme Q10). This material is an readily available lipid-soluble electron acceptor. Other quinone molecules that are electron acceptors and lipid-soluble (or soluble in the micelle core) are expected to exhibit similar behavior. Electrons can be photoexcited by absorbing light, without being limited to any particular theory. To prevent those excited electrons from negatively affecting the photostability of electro-optic displays, adding electron acceptors to the electrophoretic medium may mitigate the adverse effects of any potential electron donors, since electron transfer occurs from the electron donor or photoexcited pigment molecule to the electron acceptor, rather than from the electron donor or photoexcited pigment molecule to the pigment molecule. Example

[0115] I. Preparation of pigment particles and dispersions in Isopar E

[0116] Example 1A: White pigment particles were prepared using a titanium dioxide pigment core comprising a polymer coating as described in Example 1 of U.S. Patent No. 8,582,196. The polymer coating comprises lauryl methacrylate (LMA) and 2,2,2-trifluoroethyl methacrylate (TFEM) in a ratio of approximately 99:1. After polymerization, the solvent is replaced from toluene with Isopar E by repeated washing and removal of the supernatant.

[0117] Example 1B: White pigment particles are prepared using a titanium dioxide pigment core comprising a polymer coating. The polymer coating is formed by polymerization of lauryl methacrylate (LMA), 2,2,2-trifluoroethyl methacrylate (TFEM), and polysiloxane macromonomer (PDMS). After polymerization, the solvent is replaced from toluene with Isopar E by repeated washing and removal of the supernatant.

[0118] Example 2A: Yellow pigment particles are prepared using a C.I. Pigment Yellow 155 core comprising a polymer coating. The polymer coating was formed by polymerization of methyl methacrylate (MMA), 2,2,2-trifluoroethyl methacrylate (TFEM), and polysiloxane macromonomer (PDMS). After polymerization, the solvent was replaced from toluene with Isopar E by repeated washing and removal of the supernatant.

[0119] Example 2B: As summarized in Example 2A of U.S. Patent No. 9,697,778, a dispersion was prepared by grinding commercially available Pigment Yellow 155 particles using Solsperse 19,000 in Isopar E as the medium.

[0120] Example 3A: Magenta pigment particles were prepared using magenta dimethyl quinacridone pigment (CI Pigment Red 122), which included a polymer coating. The polymer coating was prepared using ethyl methacrylate.The solvent was formed from alkenyl benzyl chloride (VBC) and lauryl methacrylate (LMA), as described in Example 1 of U.S. Patent No. 9,697,778. After polymerization, the solvent was replaced from toluene with Isopar E by repeated washing and removal of the supernatant.

[0121] Example 4A: Cyan pigment particles were prepared using cyan copper phthalocyanine pigment (CI Pigment Blue 15:3), which included a polymer coating. The polymer coating was formed using methyl methacrylate monomer (MMA) and polysiloxane macromonomer (PDMS), as described in Example 7 of U.S. Patent No. 10,509,293.

[0122] II. Preparation of electrophoretic media.

[0123] Example 5A: A dispersion containing a white pigment from Example 1A was combined with a dispersion containing a yellow pigment from Example 2A, a dispersion containing a magenta pigment from Example 3A, a dispersion containing a cyan pigment from Example 4A, a charge control agent CCA-111, ubiquinone-10, Isopar E, and polyisobutylene (number average molecular weight 850,000). The structure and preparation of CCA-111 are described in U.S. Patent Application Publication No. 2020 / 0355978. The content of ubiquinone-10 in the electrophoresis medium of Example 5 was 3.0% by weight, based on the weight of the electrophoresis medium.

[0124] Comparative Example 6A: An electrophoresis medium was prepared similarly to that of Example 5A, but without any lightfastness additive ubiquinone-10. That is, Comparative Example 6A is a control electrophoresis medium. The conductivity of the electrophoretic medium was measured to be 430 pS / cm.

[0125] Example 7A: A dispersion containing white pigment from Example 1B was combined with a dispersion containing yellow pigment from Example 2B, a dispersion containing magenta pigment from Example 3A, a dispersion containing cyan pigment from Example 4A, Solsperse 19,000, ubiquinone-10, Isopar E, and polyisobutylene (number average molecular weight 850,000). The content of ubiquinone-10 in the electrophoretic medium of Example 5 was 3.0% by weight. The conductivity of the electrophoretic medium was 417 pS / cm.

[0126] Comparative Example 8A: A dispersion similar to the electrophoretic medium of Example 7A was prepared, except that ubiquinone-10 was replaced with ubiquinol-10. Ubiquinol-10 is a reduced form of ubiquinone-10. Ubiquinol-10 is not an electron acceptor but an electron donor. The electrophoretic medium has a conductivity of 449 pS / cm.

[0127]

[0128] Comparative Example 9A: An electrophoretic medium similar to that of Examples 7A and 8A was prepared, wherein the electrophoretic medium was free of ubiquinone-10 or panthenol-10. That is, Comparative Example 9A is a control electrophoretic medium.

[0129] III. Encapsulation of the electrophoretic medium.

[0130] Example 5B: The electrophoretic medium from Example 5A was encapsulated in a gelatin / gum arabic aggregate using the following method. Gelatin was dissolved in deionized water at 40°C and vigorously stirred. The electrophoretic medium from Example 1 was added dropwise to the stirred gelatin solution through a tube, the outlet of which was below the surface of the stirred solution. The resulting mixture was maintained at 42.5°C and continuously stirred vigorously to generate electrophoretic medium droplets in a continuous gelatin-containing aqueous phase. Then, an aqueous solution of gum arabic at 42.5°C was added to the mixture, and the pH of the mixture was lowered to about 5 to allow the gelatin / gum arabic aggregate to form, thereby forming microcapsules. The temperature of the resulting mixture was then lowered to 9°C, and an aqueous solution of glutaraldehyde (crosslinking agent) was added. The resulting mixture was then heated to 25°C and vigorously stirred for 12 hours. The resulting microcapsules were separated using sieves with mesh sizes of 20 μm and 45 μm to obtain microcapsules with an average diameter of approximately 44 μm.

[0131] Comparative Example 6B: The encapsulation process described in Example 5B was repeated for the encapsulation of the electrophoretic medium prepared in Comparative Example 6A.

[0132] Comparative Example 7B: The encapsulation process described in Example 5B was repeated for the encapsulation of the electrophoretic medium prepared in Comparative Example 7A.

[0133] Comparative Example 8B: The encapsulation process described in Example 5B was repeated for the encapsulation of the electrophoretic medium prepared in Comparative Example 8A.

[0134] Comparative Example 9B: The encapsulation process described in Example 5B was repeated for the encapsulation of the electrophoretic medium prepared in Comparative Example 9A.

[0135] Samples of microcapsules from Examples 7B, 8B, and 9B were observed using a microscope. Microscopic images are shown in Figures 4, 5, and 6, respectively, on pages 17 / 19 of the specification, CN 122029481 A. The images of the microcapsules in all three examples are similar, and there is no sign of microcapsule aggregation. This indicates that the presence of ubiquinone-10 does not affect the quality of the microcapsules.

[0136] IV. Preparation of Microcapsule Slurry

[0137] Example 5C1: The sieved microcapsule solution prepared in Example 5B was adjusted to pH 9, and the microcapsules were allowed to settle by gravity or centrifugation. After settling, excess water was removed. A poly(vinyl alcohol) binder solution (19% aqueous solution) was added to the concentrated capsule dispersion at a concentration of 60 mg per gram of microcapsule. The resulting slurry was mixed overnight.

[0138] Comparative Example 6C1: The preparation process of the microcapsule slurry in Example 5C was repeated using the sieved microcapsule solution prepared in Comparative Example 6B.

[0139] Example 7C1: The preparation process of the microcapsule slurry in Example 5C was repeated using the sieved microcapsule solution prepared in Example 7B.

[0140] Comparative Example 8C1: The preparation process of the microcapsule slurry in Example 5C was repeated using the sieved microcapsule solution prepared in Comparative Example 5B.

[0141] Comparative Example 9C1: The preparation process of the microcapsule slurry in Example 5C was repeated using the sieved microcapsule solution prepared in Comparative Example 9B.

[0142] Example 5C2: The preparation process of the microcapsule slurry in Example 5C1 was repeated, but the poly(vinyl alcohol) solution was replaced with a polyurethane dispersion.

[0143] Example 6C2: The preparation process of the microcapsule slurry in Example 6C1 was repeated, but the poly(vinyl alcohol) solution was replaced with a polyurethane dispersion.

[0144] V. Preparation of a Color Electro-Optical Display

[0145] Example 5D: The slurry prepared in Example 5C1 was bar-coated onto a 127-micrometer-thick polyester film coated with indium tin oxide (ITO), which served as the first electrode layer. The coated film was oven-dried to produce a film with a thickness of approximately 30 micrometers. The membrane is essentially a monolayer microcapsule on ITO. A front panel laminate was prepared from the resulting membrane by laminating a polyurethane adhesive onto the capsule layer (see U.S. Patent No. 6,982,178). The front panel laminate was then laminated onto a segmented graphite backing plate, which contained a graphite layer on a polyester film, to produce a color electro-optic display suitable for measuring its electro-optic properties. The color electro-optic display was equilibrated at a temperature of 25°C and a relative humidity of 50% for five days.

[0146] Comparative Example 6D: The preparation process of the electro-optic display of Example 5D was repeated using the slurry from Comparative Example 6C1.

[0147] Example 7D: The preparation process of the electro-optic display of Example 5D was repeated using the slurry from Example 7C1.

[0148] Comparative Example 8D: The preparation process of the electro-optic display of Example 5D was repeated using the slurry from Comparative Example 8C1.

[0149] Comparative Example 9D: The preparation process of the electro-optic display of Example 5D was repeated using the paste from Comparative Example 9C1.

[0150] Example 5E: The preparation process of the electro-optic display of Example 5D was repeated using the paste from Example 5C2.

[0151] Comparative Example 6E: The preparation process of the electro-optic display of Example 5D was repeated using the paste from Comparative Example 6C2.

[0152] VI. Evaluation of the lightfastness of the color electro-optic display.

[0153] The lightfastness of the color electro-optic displays of Examples 5D, Comparative Example 6D, Example 7D, Comparative Example 8D, Comparative Example 9D, Example 5E, and Comparative Example 6E was evaluated by irradiating one half of each display while keeping the other half opaque. The opaque half served as a control for the exposed portion of the display. The experiment was conducted in an environment with controlled temperature and humidity. The evaluation involved the following steps: (a) placing the display in a chamber with a relative humidity of about 50% and a temperature of about 25°C, and (b) using D65Half of the display was illuminated by (6500K) CIE light. D65 (6500K) CIE roughly corresponds to the average midday light in Western / Northern Europe (including direct sunlight and diffused light from a clear sky), and is therefore referred to as a daylight source.

[0154] The color gamut of each color electro-optic display was measured according to the electro-optic test procedure described in the next section. An arbitrary evaluation value of the display’s lightfastness was calculated by comparing the percentage of color gamut loss of the exposed and unexposed areas relative to the exposed value in the specification 18 / 19, page 23, CN 122029481 A. Panels with smaller color gamut loss % were considered to have higher lightfastness.

[0155] VII. Evaluation method of electro-optic performance

[0156] The electro-optic displays from Example 5D, Comparative Example 6D, Example 5E, Comparative Example 6E, Example 7D, Comparative Example 8D and Comparative Example 9D were electrically driven to produce eight optical states. An electrophoresis apparatus was addressed using an electrical pulse sequence (such a sequence is referred to as a “waveform”). In the following description, the voltage used in the waveforms is the voltage supplied to the rear electrode of the display, assuming that the electrode on the front (viewing) side of the display is the first electrode of all pixels and grounded. The color state of the display was recorded (measured in CIELab L*, a*, and b* units). The color gamut of each display was measured by calculating the convex hull volume containing each color state generated by the test waveform set. Type I electrophoretic media correspond to Example 5A and Comparative Example 6A. Type II electrophoretic media correspond to Example 7A, Comparative Example 8A, and Comparative Example 9A. The evaluation results of the electro-optic performance are summarized in Table 1.

[0157]

[0158]

[0159] The results clearly show that the introduction of the electron acceptor ubiquinone-10 into the electrophoretic media reduces the amount of color gamut loss caused by light exposure, expressed as a percentage of color gamut loss in Table 1. In addition, Table 1 shows that the addition of the electron donor ubiquinol-10 (the reduced form of ubiquinone-10) to the electrophoretic media has an adverse effect on the lightfastness of the color electro-optic display. Beneficial effects of electron acceptors were observed for both different types of electrophoretic displays (Type I and Type II) and for both different types of adhesives (polyvinyl alcohol and polyurethane). [Instruction manual 19 / 19, page 24, CN 122029481 A, Figure 1, Figure 2; Instruction manual Figure 1 / 3, page 25, CN 122029481 A, Figure 3, Figure 4; Instruction manual Figure 2 / 3, page 26, CN 122029481 A, Figure 5, Figure 6; Instruction manual Figure 3 / 3, page 27, CN 122029481 A]

Claims

1. A color electro-optical display, comprising, in sequence: The first electrode layer includes a light-transmitting electrode; An electro-optic material layer comprising an electrophoretic medium encapsulated in a plurality of microunits or microcapsules, the electrophoretic medium comprising a plurality of first-type charged pigment particles, a plurality of second-type charged pigment particles, a lightfastness additive, and a nonpolar liquid, the lightfastness additive being an electron acceptor and present in the electrophoretic medium at a content of 0.1% to 6.0% by weight. The second electrode layer includes multiple pixel electrodes.

2. The color electro-optic display of claim 1, wherein the lightfastness additive is selected from substituted 1,4-benzoquinone, substituted 1,2-benzoquinone, substituted naphthoquinone, and substituted anthraquinone, wherein the substituted 1,4-benzoquinone, the substituted 1,2-benzoquinone, the substituted naphthoquinone, and the substituted anthraquinone have at least one substituent comprising an alkyl, cycloalkyl, or alkenyl group, and wherein the at least one substituent has 10 to 120 carbon atoms.

3. The color electro-optic display of claim 2, wherein the substituted 1,2-benzoquinone, the substituted 1,4-benzoquinone, the substituted naphthoquinone, and the substituted anthraquinone have at least one substituent, the at least one substituent being represented by formula I or formula II, wherein n is an integer from 2 to 20, and wherein m is an integer from 1 to 20.

4. The color electro-optic display of claim 2, wherein the lightfastness additive is a substituted 1,4-benzoquinone represented by formula III. R1 is represented by formula I or formula II, where n is an integer from 2 to 20 and m is an integer from 1 to 20, and where R2 to R4 are independently selected from hydrogen, alkyl groups, alkenyl groups, aryl groups and heteroatom groups containing heteroatoms of groups V-VII of the periodic table.

5. The color electro-optic display of claim 4, wherein R1 is represented by formula II, m is an integer from 2 to 20, and wherein each of R2, R3 and R4 is independently selected from hydrogen, alkyl, alkenyl and alkoxy groups.

6. The color electro-optic display of claim 5, wherein R2 is a methyl group, and wherein R3 and R4 are methoxy groups.

7. The color electro-optic display of claim 5, wherein R2 is hydrogen, and wherein R3 and R4 are methyl groups.

8. The color electro-optic display of claim 7, wherein the lightfast additive is represented by formula IV or formula V. 。 9. The color electro-optic display of claim 2, wherein the molecular structure of the lightfastness additive is a substituted benzoquinone represented by formula VI. ， Each of R5, R6 and R7 may be independently selected from hydrogen, alkyl, alkenyl and alkoxy groups, and o is an integer from 2 to 20.

10. The color electro-optic display of claim 2, wherein the lightfastness additive is a substituted naphthoquinone, the substituted naphthoquinone being represented by formula VII. Among them, R8, R9, R 10 R 11 and R 12 Each of them may be independently selected from hydrogen, alkyl, alkenyl and alkoxy groups, and wherein p is an integer from 2 to 20.

11. The color electro-optic display of claim 2, wherein the lightfastness additive is a substituted naphthoquinone, the substituted naphthoquinone being represented by formula VIII. Where R 13 R 14 R 15 R 16 and R 17 Each of the groups can be independently selected from hydrogen, alkyl, alkenyl and alkoxy groups, and q is an integer from 2 to 20.

12. The color electro-optic display of claim 11, wherein the molecular structure of the lightfastness additive is represented by formula VIII, wherein R 13 R 14 R 15 R 16 It is hydrogen, and R 17 It is a methyl group.

13. The color electro-optical display of claim 12, wherein q is selected from 3, 4, 7 and 9.

14. The color electro-optic display according to any one of claims 1 to 13, wherein the electrophoretic medium further comprises a plurality of third-type charged pigment particles and a plurality of fourth-type charged pigment particles.

15. The color electro-optic display of claim 14, wherein the charged pigment particles of the first, second, third and fourth types have colors selected from white, black, cyan, magenta, yellow, blue, green and red.

16. The color electro-optic display of claim 14, wherein the charged pigment particles of the first, second, third, and fourth types are white, cyan, magenta, and yellow, respectively.

17. The color electro-optic display according to any one of claims 1 to 16, wherein the electro-optic material layer comprises a plurality of microcapsules and an adhesive.

18. The color electro-optic display of claim 17, wherein the color electro-optic display further comprises a first adhesive layer disposed between the electro-optic material layer and the second electrode layer.

19. The color electro-optic display of claim 18, wherein the color electro-optic display further comprises a second adhesive layer disposed between the electro-optic material layer and the first electrode layer.

20. The color electro-optic display according to any one of claims 1 to 16, wherein the electro-optic material layer comprises a plurality of micro-units, each of the plurality of micro-units having a micro-unit bottom, a partition wall, an opening, and a sealing layer extending across the opening, the sealing layer being adjacent to the second electrode layer.

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