Electro-optic displays with edge seal components and methods of making the same

Abstract

An electro-optical display comprises a backplane having at least one electrode, a layer of an electro-optical material disposed adjacent to the backplane, and a light-transmitting electrically conductive layer disposed on the side opposite to the layer of the electro-optical material from the backplane. The electro-optical display also comprises a rod member disposed laterally adjacent to the backplane, the electro-optical material, and the light-transmitting electrically conductive layer. A first barrier layer is disposed adjacent to a first side of the rod member and the light-transmitting electrically conductive layer, and a second barrier layer is disposed on a second side of the rod member and on the backplane. The second side is the side opposite to the first side of the rod member. A flexible barrier tape extends from an edge portion of the first barrier layer, around the rod member, to an edge portion of the second barrier layer.

Description

Technology Field

[0001] Cross-reference of related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 313,974 filed February 25, 2022, the entire contents of which are incorporated herein by reference. Additionally, the entire contents of any patent, published application or other published work referenced herein are incorporated herein by reference. Background Technology

[0003] The present invention relates to an electro-optical display having an edge seal. The present invention also provides processes for manufacturing such an electro-optical display. The present invention is particularly, but not exclusively, intended for use with displays comprising encapsulated electrophoretic media. However, the present invention may also use various other types of electro-optical media that are "solid" in the sense of having solid outer surfaces, but the media may have internal cavities containing fluid (liquid or gas), and often do so. These "solid electro-optical displays" include encapsulated electrophoretic displays, encapsulated liquid crystal displays, and other types of displays discussed below.

[0004] Electro-optical displays comprise layers of electro-optical materials, and the term is used herein in its conventional sense in imaging technology to refer to a material having first and second display states that differ in at least one engineering property, and the material changes from the first display state to the second display state by the application of an electric field to the material. Although the optical property is typically a color perceptible to the human eye, it may be other optical properties such as optical transmission, reflectance, luminescence, or pseudo-color in the sense of a change in reflectance of electromagnetic wavelengths outside the visible range in the case of displays intended for machine reading.

[0005] The terms “bistable” and “bistable” are used herein in their conventional sense to refer to displays comprising display elements having first and second display states that differ in at least one optical characteristic, and accordingly, after any given element is driven by an addressing pulse of a finite duration to assume either the first or second display state, and after the addressing pulse is terminated, the state will persist for at least several times, e.g., at least four times, the minimum duration of the addressing pulse required to change the state of the display element. It is indicated in U.S. Patent Application Publication No. 2002 / 0180687 that some grayscale-capable particle-based electrophoretic displays are stable in their extreme black and white states as well as in their intermediate gray states, and that the same is true for other types of electro-optical displays. Although it is appropriate to call this type of display "multi-stable" rather than "bistable," for convenience, the term "bistable" may be used herein to cover both bistable and multi-stable displays.

[0006] Several types of electro-optical displays are known. One type of electro-optical display is a rotating bichromatic member type, as described, for example, in U.S. Patent 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 (this type of display is often referred to as a “rotating bichromatic ball” display, but the term “rotating dichromatic member” is preferred as more accurate because the rotating members in some of the aforementioned patents are not spherical). Such displays use two or more sections of various optical properties and a number of small bodies (typically spherical or cylindrical) having internal dipoles. These bodies are suspended in liquid-filled vacuoles within a matrix, and the vacuoles are filled with liquid so that the bodies rotate freely. The appearance of the display is changed by the application of an electric field, thereby rotating the bodies to various positions and changing which of the body sections is seen through the visible surface. This type of electro-optical medium is typically bistable.

[0007] Another type of electro-optical display uses an electrochromic medium in the form of a nanochromic film comprising an electrode formed at least partially from a semiconducting metal oxide, for example, and a plurality of reversibly color-changing dye molecules 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). Also see Bach, U. et al., Adv. Mater., 2002, 14(11), 845. Nanochromic films of this type are also described, for example, in U.S. Patent Nos. 6,301,038; 6,870,657; and 6,950,220. This type of medium is also typically bistable.

[0008] One type of electro-optical display, which has been the subject of intensive research and development for many years, is a particle-based electrophoretic display in which multiple charged particles move through a suspension fluid under the influence of an electric field. Compared to liquid crystal displays, electrophoretic displays can possess properties such as good brightness and contrast, wide viewing angles, state bistable, and low power consumption. Nevertheless, problems with the long-term image quality of these displays have hindered their widespread use. For example, the particles constituting electrophoretic displays tend to settle, resulting in an insufficient service life for these displays.

[0009] As mentioned above, electrophoretic media require the presence of a fluid. In most prior art electrophoretic media, this fluid is a liquid, but electrophoretic media can be prepared using a gaseous fluid; see, for example, Kitamura, T. et al., "Electrical toner movement for electronic paper-like display", IDW Japan, 2001, Paper HCS1-1, and Yamaguchi, Y. et al., "Toner display using insulative particles charged triboelectrically", IDW Japan, 2001, Paper AMD4-4). U.S. Patent Application No. 2005 / 0001810; European Patent Applications 1,462,847; 1,482,354; 1,484,635; 1,500,971; 1,501,194; 1,536,271; 1,542,067; 1,577,702; See also 1,577,703; and 1,598,694; and international applications WO 2004 / 090626; WO 2004 / 079442; and WO 2004 / 001498. These gas-based electrophoretic media appear to be prone to the same types of problems caused by such particle sedimentation as liquid-based electrophoretic media when the media are used in an orientation that allows particle sedimentation, for example, with the media placed in a vertical plane. In fact, particle sedimentation appears to be a more serious problem in gas-based electrophoretic media than in liquid-based electrophoretic media, because the lower viscosity of gaseous suspended fluids compared to liquid suspended fluids allows for faster sedimentation of electrophoretic particles.

[0010] Several patents and applications assigned to or in the name of the Massachusetts Institute of Technology (MIT) and E Ink Corporation, describing encapsulated electrophoretic media, have recently been disclosed. Such encapsulated media comprise several small capsules, each comprising an internal phase containing electrophoretic mobile particles suspended in a liquid suspension medium, and a capsule wall surrounding the internal phase. Typically, the capsules themselves are retained within a polymeric binder to form a coherent layer positioned between two electrodes. Examples of this type of encapsulated media are U.S. Patent Nos. 5,930,026; 5,961,804; 6,017,584; 6,067,185; 6,118,426; 6,120,588; 6,120,839; 6,124,851; 6,130,773; 6,130,774; 6,172,798; 6,177,921; 6,232,950; 6,249,271; 6,252,564; 6,262,706; 6,262,833; 6,300,932; 6,312,304; 6,312,971; 6,323,989; 6,327,072; 6,376,828; 6,377,387; 6,392,785; 6,392,786; 6,413,790; 6,422,687; 6,445,374; 6,445,489; 6,459,418; 6,473,072; 6,480,182; 6,498,114; 6,504,524; 6,506,438; 6,512,354; 6,515,649; 6,518,949; 6,521,489; 6,531,997; 6,535,197; 6,538,801; 6,545,291; 6,580,545; 6,639,578; 6,652,075; 6,657,772; 6,664,944; 6,680,725; 6,683,333; 6,704,133; 6,710,540; 6,721,083; 6,724,519; 6,727,881; 6,738,050; 6,750,473; 6,753,999;6,816,147; 6,819,471; 6,822,782; 6,825,068; 6,825,829; 6,825,970; 6,831,769; 6,839,158; 6,842,167; 6,842,279; 6,842,657; 6,864,875; 6,865,010; 6,866,760; 6,870,661; 6,900,851; 6,922,276; 6,950,200; 6,958,848; 6,967,640; 6,982,178; 6,987,603; 6,995,550; 7,002,728; 7,012,600; 7,012,735; 7,023,430; 7,030,412; 7,030,854; 7,034,783; 7,038,655; 7,061,663; 7,071,913; 7,075,502; 7,075,703; 7,079,305; 7,106,296; 7,109,968; 7,110,163; 7,110,164; 7,116,318; 7,116,466; 7,119,759; and 7,119,772; and U.S. patent application publication numbers 2002 / 0060321; 2002 / 0090980; 2002 / 0180687; 2003 / 0011560; 2003 / 0102858; 2003 / 0151702; 2003 / 0222315; 2004 / 0014265; 2004 / 0075634; 2004 / 0094422; 2004 / 0105036; 2004 / 0112750; 2004 / 0119681; 2004 / 0136048; 2004 / 0155857; 2004 / 0180476; 2004 / 0190114; 2004 / 0196215; 2004 / 0226820; 2004 / 0239614; 2004 / 0257635; 2004 / 0263947; 2005 / 0000813; 2005 / 0007336; 2005 / 0012980; 2005 / 0017944; 2005 / 0018273; 2005 / 0024353; 2005 / 0062714; 2005 / 0067656; 2005 / 0078099; 2005 / 0099672; 2005 / 0122284; 2005 / 0122306; 2005 / 0122563;2005 / 0122565; 2005 / 0134554; 2005 / 0146774; 2005 / 0151709; 2005 / 0152018; 2005 / 0152022; 2005 / 0156340; 2005 / 0168799; 2005 / 0179642; 2005 / 0190137; 2005 / 0212747; 2005 / 0213191; 2005 / 0219184; 2005 / 0253777; 2005 / 0270261; 2005 / 0280626; 2006 / 0007527; 2006 / 0024437; 2006 / 0038772; 2006 / 0139308; 2006 / 0139310; 2006 / 0139311; 2006 / 0176267; 2006 / 0181492; 2006 / 0181504; 2006 / 0194619; 2006 / 0197736; 2006 / 0197737; 2006 / 0197738; 2006 / 0198014; 2006 / 0202949; and 2006 / 0209388; and International Application Publication Nos. WO 00 / 38000; WO 00 / 36560; Described in WO 00 / 67110; and WO 01 / 07961; and European Patent Nos. 1,099,207 B1 and 1,145,072 B1.;

[0011] Many of the patents and applications cited above recognize that, by replacing the walls surrounding distinct microcapsules in an encapsulated electrophoretic medium with a continuous phase, the electrophoretic medium can produce a so-called polymer-dispersed electrophoretic display comprising multiple distinct droplets of an electrophoretic fluid and a continuous phase of a polymer material, and that the distinct droplets of the electrophoretic fluid in such a polymer-dispersed display may be considered as capsules or microcapsules even though a distinct capsule membrane is not associated with each individual droplet; refer, for example, to U.S. Patent No. 6,866,760 cited above. Accordingly, for the purposes of this application, such a polymer-dispersed electrophoretic medium is considered a subspecies of an encapsulated electrophoretic medium.

[0012] A related type of electrophoretic display is a so-called "microcell electrophoretic display." In a microcell electrophoretic display, charged particles and suspended fluids are not encapsulated within microcapsules but are instead retained within a plurality of cavities formed within a carrier medium, typically a polymer film. For example, refer to International Application Publication No. WO 02 / 01281 and published U.S. Application No. 2002 / 0075556, both of which were assigned to Sipix Imaging, Inc.

[0013] Another type of electro-optical display is the electrowetting display developed by Philips and described by Hayes, RA, et al., in "Video-Speed ​​Electronic Paper Based on Electrowetting", Nature, 425, 383-385 (2003). It is indicated in U.S. Patent No. 7,420,549 that such electrowetting displays can be bistable.

[0014] Other types of electro-optical materials may also be used in the present invention. In particular, bistable ferroelectric liquid crystal displays (FLC) are known in the art.

[0015] Electrophoretic media are often opaque (for example, in many electrophoretic media, particles substantially block the transmission of visible light through the display) and operate in a reflective mode, but many electrophoretic displays can be made to operate in a so-called shutter mode where one display state is substantially opaque and the other is light-transmitting. For example, see the aforementioned U.S. Patent Nos. 6,130,774 and 6,172,798 and U.S. Patent Nos. 5,872,552; 6,144,361; 6,271,823; 6,225,971; and 6,184,856. Dielectrophoretic displays similar to electrophoretic displays but relying on variations in electric field intensity may operate in a similar mode; see U.S. Patent No. 4,418,346.

[0016] Encapsulated or microcell electrophoretic displays typically do not suffer from the clustering and settling failure modes of conventional electrophoretic devices and provide additional advantages, such as the ability to print or coat displays on a wide variety of flexible and rigid substrates. (The use of the word “print” is intended to include, without limitation, all forms of printing and coating, including pre-measured coatings, e.g., patch die coating, slot or extrusion coating, slide or cascade coating, curtain coating; roll coatings, e.g., knife-over-roll coating, forward and reverse roll coating; gravure coating; dip coating; spray coating; meniscus coating; spin coating; brush coating; air knife coating; silkscreen printing processes; electrostatic printing processes; thermal printing processes; inkjet printing processes; electrophoretic deposition; and other similar techniques.) Thus, the resulting display can be flexible. Furthermore, because the display medium can be printed (using various methods), the display itself can be manufactured at a low cost.

[0017] An electro-optical display generally comprises a layer of electro-optical material and at least two other layers disposed on opposite sides of the electro-optical material, one of which is an electrode layer. In most such displays, both of the layers are electrode layers, and one or both of the electrode layers are patterned to define pixels of the display. For example, one electrode layer may be patterned with elongated row electrodes and the other electrode layer may be patterned with elongated column electrodes perpendicular to the row electrodes, and pixels are defined by the intersections of the row and column electrodes. Alternatively, and more generally, one electrode layer has the form of a single continuous electrode, and the other electrode layer is patterned as a matrix of pixel electrodes that each define one pixel of the display. In other types of electro-optical displays intended for use with a stylus, print head, or similar movable electrode separated from the display, only one of the layers adjacent to the electro-optical layer comprises an electrode, and the layer on the opposite side of the electro-optical layer is typically a protective layer intended to prevent the movable electrode from damaging the electro-optical layer.

[0018] The fabrication of a three-layer electro-optical display generally involves at least one lamination operation. For example, in several of the aforementioned MIT and E Ink patents and applications, a process for manufacturing an encapsulated electrophoretic display is described in which an encapsulated electrophoretic medium comprising capsules in a binder is coated onto a flexible substrate comprising an indium-tin-oxide (ITO) or similar conductive coating (which acts as one electrode of the final display) on a plastic film, and the capsules / binder coating is dried to form a coherent layer of the electrophoretic medium firmly attached to the substrate. Separately, a backplane is fabricated comprising an array of pixel electrodes and a suitable arrangement of conductors for connecting the pixel electrodes to a driving circuit. To form the final display, the substrate having the capsule / binder layer is laminated to the backplane using a lamination adhesive. (A very similar process can be used to manufacture electrophoretic displays usable with a stylus or similar movable electrode by replacing the backplane with a simple protective layer, such as a plastic film, on which the stylus or other movable electrode can slide.) In one form of this process, the backplane is flexible in itself and is prepared by printing 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. Similar manufacturing techniques can be used with other types of electro-optical displays. For example, a microcell electrophoretic medium or a rotational dichromatic component medium may be laminated to the backplane in substantially the same way as the encapsulated electrophoretic medium.

[0019] As discussed in the aforementioned U.S. Patent No. 6,982,178, many components used in solid-state electro-optical displays, and the methods used to manufacture such displays, are derived from the technology used in liquid crystal displays (LCDs), which are electro-optical displays, although they use liquids rather than solid media. For example, a solid-state electro-optical display may utilize an active matrix backplane comprising an array of transistors or diodes and a corresponding array of pixel electrodes, and "continuous" front electrodes on a transparent substrate (in the sense of multiple pixels and electrodes extending generally across the entire display), and these components are essentially identical to those of an LCD. However, the methods used to assemble an LCD cannot be used for a solid-state electro-optical display. An LCD is typically assembled by forming a backplane and front electrodes on separate glass substrates, then adhesively fixing these components to leave a small aperture between them, placing the resulting assembly under vacuum, and immersing the assembly in a liquid crystal bath so that the liquid crystal flows through the aperture between the backplane and the front electrodes. Finally, with the liquid crystal in place, the aperture is sealed to provide the final display.

[0020] This LCD assembly process cannot be easily transferred to solid-state electro-optical displays. Because electro-optical materials are solid, they must exist between the backplane and the front electrode before these two constants are fixed to each other. Furthermore, unlike liquid crystal materials which are simply placed between the front electrode and the backplate without being attached to either of them, solid-state electro-optical media generally need to be fixed to both; in most cases, solid-state electro-optical media are formed on the front electrode, as this is generally easier than forming the media on the backplane containing the circuit, and the front electrode / electro-optical media combination is typically laminated to the backplane by covering the entire surface of the electro-optical media with an adhesive and laminating under heat, pressure, and possibly a vacuum.

[0021] Electro-optical displays are often expensive; for example, the cost of a color LCD found in a portable computer typically accounts for a significant portion of the computer's total cost. As the use of electro-optical displays spreads to devices such as cellular phones and personal digital assistants (PDAs), which are much cheaper than portable computers, there is significant pressure to reduce the costs of such displays. As discussed above, the ability to form layers of some solid electro-optical media by printing techniques on flexible substrates opens up the possibility of reducing the cost of electro-optical components of displays by using mass production techniques, such as roll-to-roll, using commercial equipment used to produce coating papers, polymer films, and similar media. However, such equipment is expensive, and the area of ​​electro-optical media currently on the market may be insufficient to justify dedicated equipment, so it may be necessary to transport the coated media from a commercial coating plant to a plant used for the final assembly of electro-optical displays without damaging the relatively fragile layer of the electro-optical media.

[0022] Furthermore, most prior art methods for the final lamination of electrophoretic displays are essentially batch methods in which the electro-optical medium, lamination adhesive, and backplane are combined only immediately before final assembly, and it is desirable to provide a method that is more suitable for mass production.

[0023] The aforementioned U.S. Patent No. 6,982,178 describes a method for assembling a solid-state electro-optical display (including a particle-based electrophoretic display) that is well adapted for mass production. Essentially, this concurrently pending application describes a so-called “front laminate” (“FPL”) comprising, in order: a light-transmitting electrically conductive layer; a layer of a solid-state electro-optical medium electrically in contact with the electrically conductive layer; an adhesive layer; and a release sheet. Typically, the light-transmitting electrically conductive layer is to be carried on a light-transmitting substrate, which is preferably flexible in the sense that the substrate can be manually wrapped around a drum (say) to a diameter of 10 inches (254 mm) without permanent deformation. The term “transmittance” is used to mean that the layer thus designated transmits sufficient light to enable an observer viewing through the layer to observe changes in the display states of the electro-optical medium, which would generally be seen through the electrically conductive layer and (if present) the adjacent substrate. The substrate will typically be a polymer film and will generally have a thickness in the range of about 1 to about 25 mil (25 to 634 µm), preferably about 2 to about 10 mil (51 to 254 µm). The electrically conductive layer may conveniently be, for example, a thin metal layer of aluminum or ITO, or a conductive polymer. Poly(ethylene terephthalate) (PET) films coated with aluminum or ITO are commercially available, for example, as "aluminumized Mylar" ("Mylar" is a registered trademark) from EIdu Pont de Nemours & Company, Wilmington, DE, and such commercial materials may be used with good results in front lamination.

[0024] The aforementioned U.S. Patent No. 6,982,178 also describes a method for testing an electro-optical medium in a front laminate before integrating the front laminate into a display. In this test method, a release sheet is provided with an electrically conductive layer, and a voltage sufficient to alter the optical state of the electro-optical medium is applied between the electrically conductive layer and the electrically conductive layer on the opposite side of the electro-optical medium. Observation of the electro-optical medium subsequently reveals any defects in the medium and avoids laminating the defective electro-optical medium into the display, thereby incurring the resulting cost of scrapping the entire display rather than the defective front laminate.

[0025] The aforementioned U.S. Patent No. 6,982,178 also describes a second method for testing an electro-optical medium in a front laminate by placing an electrostatic charge on a release sheet and thereby forming an image on the electro-optical medium. This image is then observed in the same manner as the preceding one to detect any defects in the electro-optical medium.

[0026] The aforementioned 2004 / 0155857 describes a so-called “double release film,” which is an essentially simplified version of the front laminate of the aforementioned U.S. Patent No. 6,982,178. One form of the double release sheet comprises a layer of solid electro-optical medium sandwiched between two adhesive layers, one or both of the adhesive layers being covered by the release sheet. Another form of the double release sheet comprises a layer of solid electro-optical medium sandwiched between two release sheets. Both forms of the double release film are intended for use in a process generally similar to the process for assembling an electro-optical display from the previously described front laminate, but involve two separate laminations; Typically, in the first lamination, the double release sheet is laminated to the front electrode to form the front sub-assembly, and then, in the second lamination, the front sub-assembly is laminated to the backplane to form the final display, but the order of these two laminations can be reversed if desired.

[0027] U.S. Patent No. 7,839,564 describes a so-called “inverted front laminate,” which is a variation of the front laminate described in the aforementioned U.S. Patent No. 6,982,178. This inverted front laminate comprises, in order, at least one of a light-transmitting protective layer and a light-transmitting electrically conductive layer; an adhesive layer; a layer of a solid electro-optical medium; and a release sheet. This inverted front laminate is used to form an electro-optical display having a layer of lamination adhesive between an electro-optical layer and a front electrode or a front substrate; a second, typically thin adhesive layer may or may not be present between the electro-optical layer and a backplane. Such electro-optical displays can combine good resolution and good low-temperature performance.

[0028] The aforementioned U.S. Patent No. 7,839,564 also describes various methods designed for the mass production of electro-optical displays using inverted front laminates. Some forms of these methods are “multi-up” methods designed to allow the lamination of components for multiple electro-optical displays at once.

[0029] The aforementioned U.S. Patent No. 6,982,178 also explains the importance of protecting electro-optical media from environmental contamination, as some electro-optical media are sensitive to humidity and ultraviolet radiation and most of these media are susceptible to mechanical damage. This patent illustrates, in FIG. 10, a process in which a protective film is laminated over a front laminate in the same lamination operation in which the front laminate is laminated to a backplane; such a protective film can protect the electro-optical media from the ingress of moisture, other liquids, and some gases. However, despite such a protective film, the edges of the electro-optical media are still exposed to the environment, and this patent also teaches that it is desirable for the display to include an edge seal that serves to prevent the ingress of moisture and other contaminants around the outer edges of the display. Various types of edge seals are illustrated in FIG. 11-17 of this patent. This edge seal may consist of a metallized foil or other barrier foil attached to the edge of the FPL, a dispensed sealant (thermally, chemically, and / or radiation-cured), polyisobutylene or acrylate-based sealants, etc. It has been found that hybrid radiation and thermal curing sealants (i.e., thermal post-baked UV-cured types) provide specific advantages to display system performance. The Threebond 30Y-491 material (from Threebond Corporation, Cincinnati, OH) has been found to possess good water vapor barrier properties, low viscosity at elevated temperatures for easy dispensing of the edge seal material, good wetting properties, and manageable curing properties. Those skilled in the art and familiar with advanced sealants will be able to identify other sealants that provide similar performance.

[0030] FIG. 20 of the aforementioned U.S. Patent 6,982,178 illustrates an electro-optical display having a front protection layer and an edge seal. This display comprises a thin-film transistor (TFT) backplane that is generally similar to backplanes used with liquid crystal displays and has associated thin-film transistors and conductors for independently controlling a matrix of pixel electrodes and a voltage applied to the pixel electrodes. A tape connection package is connected to the periphery of the backplane and is provided with a driver integrated circuit (for controlling the operation of the display); the tape connection package is also connected to a printed circuit board comprising an additional circuitry for controlling the operation of the display.

[0031] On the upper surface of the backplane (as illustrated in FIG. 20 above), a lamination adhesive layer, an electro-optical medium layer, a front electrode, and a front substrate are disposed; both the front electrode and the front substrate are conveniently formed from an indium-tin-oxide coated polymer film, and as previously mentioned, such coated films are readily available commercially. The lamination adhesive layer, the electro-optical layer, the front electrode, and the front substrate are all derived from a front laminate laminated to the backplane. A portion of the front electrode and the front substrate extends beyond the electro-optical layer, and in the extended 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 backplane, while the adhesive layer secures the extended portion of the front electrode to the backplane.

[0032] On the front substrate, a first layer of optically transparent adhesive, a barrier film, a second layer of optically transparent adhesive, and an additional, relatively thick protective film provided on its exposed surface are disposed in succession. The protective film serves to block ultraviolet radiation from reaching the electro-optical layer and also prevents atmospheric moisture or other contaminants from reaching this layer.

[0033] To form a complete seal around the electro-optical layer, the barrier film, the second layer of optically transparent adhesive, and the protective film are all manufactured to be larger in both dimensions than the front substrate, so that these layers have a peripheral portion that extends or "overhangs" from the outer edge of the front substrate. To complete the sealing of the electro-optical layer, a curable edge sealing material is typically injected into the overhang area through a needle dispenser and cured to form an edge seal that completely surrounds the electro-optical layer.

[0034] FIG. 3 of the aforementioned U.S. Patent No. 7,649,674 illustrates another embodiment of an electro-optical display having a front protective or barrier layer and an edge seal. This display also comprises a backplane on which a front substrate comprising a layer of lamination adhesive, a layer of electro-optical medium, and an electrically conductive film or coating is disposed. The backplane is larger than the layers of lamination adhesive, electro-optical medium, and front substrate in both length and width dimensions. Thus, the peripheral portion of the backplane extends beyond the outer edges of these layers and around its periphery.

[0035] The display further comprises a front protection or barrier sheet laminated or otherwise applied on a front substrate. The barrier sheet is manufactured to be larger than the front substrate in both length and width dimensions, so that the barrier sheet has a peripheral portion that extends or "overhangs" from the outer edge of the front substrate. The overhang portions of the barrier sheet are "pinched" down onto the edges of the front substrate using a lamination adhesive, an electro-optical medium, and a backplane, and are sealed to the peripheral portion of the backplane to form a pinched edge seal. The barrier sheet may be melted onto the surface of the backplane, for example, using laser or ultrasonic welding. Alternatively, an adhesive may be used to secure the overhang portions of the barrier sheet to the backplane. The problem to be solved

[0036] Edge seals, such as those incorporated in Fig. 20 of U.S. Patent 6,982,178 summarized above, can be effective in preventing the ingress of moisture and other environmental contaminants into the electro-optical medium. However, one of the advantages of encapsulated electrophoretic and other electro-optical media, e.g., organic light-emitting diodes (OLEDs) and microcell media, is that they are sufficiently flexible to be used in flexible displays. However, the aforementioned edge seals and similar edge seals are not suitable for use in flexible displays because the curable edge sealing material imparts rigidity to the display once it is fully cured. These types of edge seals can also add complexity to the display manufacturing process associated with accurately distributing the sealing material around the periphery of the backplane.

[0037] The edge seal incorporated in Fig. 3 of U.S. Patent No. 7,649,674 summarized above maintains the flexibility of the electro-optical display because it does not use a curable edge sealing material. However, it has been found that the areas where pinched portions of the barrier sheet adhere to the surface of the backplane may be moisture diffusion paths along the edges of the electro-optical display.

[0038] Measures to reduce or mitigate edge moisture diffusion effects typically include increasing the width of the optically inactive region around the outer periphery of the electro-optical material and / or increasing the width of the pinched portion of the barrier sheet. However, implementing any of these mitigation measures imposes a trade-off on the design of the end product incorporating the electro-optical display. For example, for a display housing of a given height and width, increasing the width of the inactive region around the edges of the electro-optical material or the pinched portion of the barrier sheet effectively reduces the visible area of ​​the display and requires a housing with a wider bezel portion to hide these unusable areas. Alternatively, if the size of the visible area is a fixed design requirement, the dimensions of the display housing must be increased to achieve the required visible area.

[0039] Additionally, when producing large flexible displays, such as those used to wrap buses or buildings, the edges are more likely to be damaged during handling and installation. This also applies to aftermarket variable transparency films that can be installed, for example, on existing windows of buildings or vehicles, such as passenger bus windows or car door roofs. If the edges or corners of such devices are damaged, moisture penetration can degrade performance or even lead to electrical short circuits or delamination.

[0040] Accordingly, the edge seal technology described in this specification includes features for solving the defects of conventional edge seals. means of solving the problem

[0041] Accordingly, in one embodiment, the subject matter presented herein provides an electro-optical display comprising: a backplane comprising at least one electrode; a layer of an electro-optical material disposed adjacent to the backplane; a light-transmitting electrically conductive layer disposed on a side opposite to the layer of the electro-optical material from the backplane; a rod member disposed laterally adjacent to the backplane, the layer of the electro-optical material, and the light-transmitting electrically conductive layer; a first barrier layer disposed adjacent to a first side of the light-transmitting electrically conductive layer and the rod member; a second barrier layer disposed on a second side of the backplane and the rod member—the second side being a side opposite to the rod member from the first side—and a flexible barrier tape extending from an edge portion of the first barrier layer around the rod member to an edge portion of the second barrier layer.

[0042] In some embodiments, the electro-optical display further comprises an edge sealing material within a flexible barrier tape. The edge sealing material is disposed at a first end of a rod member adjacent to a first corner of the electro-electro-optical display and at a second end of a rod member adjacent to a second corner of the electro-electro-optical display.

[0043] In some embodiments, the edge sealing material is a UV-curable resin. In some embodiments, the edge sealing material has a water vapor permeability of 2 to 3 g / m2 / day at 60°C to 90% relative humidity. In some embodiments, the barrier tape further comprises an adhesive layer on the surface of the barrier tape in contact with the edge portion of the first barrier layer, the rod member, and the edge portion of the second barrier layer.

[0044] In some embodiments, the rod member is cylindrical and has an average diameter between about 0.254 mm and about 2.54 mm. In some embodiments, the rod member is incorporated within the barrier tape. In some embodiments, the rod member is positioned substantially along the longitudinal center of the barrier tape.

[0045] In some embodiments, the barrier tape further comprises a layer of electrical insulating material on a surface of the barrier tape in contact with an edge portion of the first barrier layer, a rod member, and an edge portion of the second barrier layer. In some embodiments, the barrier tape further comprises a metal foil layer disposed on a surface of the barrier tape facing a surface in contact with an edge portion of the first barrier layer, a rod member, and an edge portion of the second barrier layer. In some embodiments, the barrier tape comprises a layer of adhesive material disposed on a first half of the longitudinal surface of the barrier tape and a layer of metal foil disposed on a second half of the longitudinal surface of the barrier tape. In some embodiments, the barrier tape comprises a coloring agent.

[0046] In another embodiment, the subject matter set forth herein provides an electro-optical display comprising a backplane comprising at least one electrode, a layer of electro-optical material disposed adjacent to the backplane, a light-transmitting electrically conductive layer disposed on the side opposite to the layer of electro-optical material from the backplane, and corner barrier seals disposed at each corner of the electro-optical display. The corner barrier seals comprise a barrier material having a square shape in an unfolded state and first, second, and third fold lines, wherein the first and second fold lines are perpendicular to each other and the third fold line is substantially 45 degrees from the first and second fold lines, the first, second, and third fold lines divide each other and the barrier material, the first and second fold lines are folded upward and the third fold line is folded downward to form first and second corner pockets.

[0047] In some embodiments, the electro-optical display further includes the step of forming a square-shaped barrier material into an X shape when unfolded. In some embodiments, the corner barrier seal further includes an adhesive layer disposed on the inner surface of the first and second corner pockets.

[0048] In some embodiments, a layer of electro-optical material and a light-transmitting electrically conductive layer are disposed within a first corner pocket of each corner barrier seal, and a backplane is disposed within a second corner pocket of each corner barrier seal. In some embodiments, a layer of electro-optical material, a light-transmitting electrically conductive layer, and a backplane are disposed within a first corner pocket or a second corner pocket of each corner barrier seal.

[0049] In some embodiments, the electro-optical display further comprises a light-transmitting electrically-conductive layer and a first barrier layer disposed on a first surface of each corner barrier seal, and a second barrier layer disposed on a backplane and a second surface of each corner barrier seal. In some embodiments, the first and second barrier layers are both larger in dimensions than the light-transmitting electrically-conductive layer, the layer of electro-optical material, and the backplane, leaving peripheral portions of the first and second barrier layers that extend beyond the edges of the light-transmitting electrically-conductive layer, the layer of electro-optical material, and the backplane, respectively, and the peripheral portions of the first and second barrier layers are fixed to each other, thereby sealing the edges of the electro-optical display.

[0050] In some embodiments, the electro-optical display further includes an edge sealing component extending around the periphery of the electro-optical display over the edge portion of the first barrier layer and the edge portion of the second barrier layer. In some embodiments, the edge sealing component is a barrier tape comprising polychlorotrifluoroethylene or aluminum oxide.

[0051] In another embodiment, the subject matter set forth herein provides a process for forming an electro-optical display. The method comprises the steps of: providing a front laminate comprising an electro-optical material layer and a light-transmitting electrically conductive layer; providing a backplane comprising at least one pixel electrode, wherein the backplane has length and width dimensions greater than those of the front sub-assembly; laminating the front sub-assembly to the backplane; distributing a curable edge seal material around the periphery of the backplane adjacent to the outer edges of the front sub-assembly; partially curing the curable edge seal material; laminating a barrier layer over the front sub-assembly and the partially cured edge seal material, wherein the barrier layer is sized to overhang the partially cured edge seal material; bonding the overhanging portion of the barrier layer to the surface of the backplane; and fully curing the curable edge seal material.

[0052] In some embodiments, the surface of the barrier layer comprises a layer of pressure-sensitive adhesive. In some embodiments, the step of partially curing the curable edge seal material comprises curing the curable edge seal material for about 15 to 40 seconds.

[0053] In some embodiments, the curable edge seal material has a water vapor permeability of 2 to 3 g / m2 / day at 60°C to 90% relative humidity. In some embodiments, the curable edge seal material is a polymer comprising epoxy, urethane, acrylate, or a combination thereof. In some embodiments, the curable edge seal material is UV-curable.

[0054] In another aspect, the subject matter presented in this specification provides an electro-optical display formed using the process described above.

[0055] In another embodiment, the subject of this specification provides a variable transparent window comprising a display stack, a substrate, and an edge seal material. The display stack comprises a layer of electro-optical material disposed between the lower surface of an upper light-transmitting electrically conductive layer and the upper surface of the lower light-transmitting electrically conductive layer, and a barrier layer disposed on the upper surface of the upper light-transmitting electrically conductive layer. In some embodiments, a first adhesive layer is disposed between the barrier layer and the upper light-transmitting electrically conductive layer. The display stack is disposed on a substrate. In some embodiments, the length and width of the substrate are greater than the length and width of the display stack. In some embodiments, a second adhesive layer is disposed between the display stack and the substrate. An edge sealing material is disposed along the periphery edge of the display stack and on a portion of the substrate. The edge sealing material comprises a first horizontal section disposed over a portion of the upper surface of the barrier layer, a vertical section disposed adjacent to the entire outer edge of the display stack, and a second horizontal section disposed over a portion of the top surface of the substrate. In some embodiments, a third adhesive layer is disposed between the edge sealing material and both the display stack and the substrate.

[0056] In some embodiments, a layer of electro-optical material comprises a plurality of microcells. In some embodiments, a layer of electro-optical material comprises a layer of sealing material disposed on the open ends of the plurality of microcells. In some embodiments, the plurality of microcells each comprise a protruding structure. In some embodiments, the protruding structure is formed from one or more geometric shapes. In some embodiments, the protruding structure is formed from a conical shape formed on a cylindrical shape.

[0057] These and other aspects of the present invention will be apparent from the following description. Brief explanation of the drawing

[0058] FIG. 1 is a schematic cross-sectional view illustrating an exemplary embodiment of a sealed electro-optical display according to the subject matter presented in this specification. FIGS. 2a through 2d are cross-sectional plans illustrating steps of a method for manufacturing an electro-optical display having edge seal components according to the subject matter set forth in this specification. FIG. 3 is a schematic cross-sectional view of an adhesive barrier tape having an integral rod according to the subject matter presented in this specification. FIG. 4 is a schematic cross-sectional cutaway view illustrating an exemplary embodiment of a sealed electro-optical display comprising an adhesive barrier tape having an integral rod according to the subject matter presented in this specification. FIGS. 5a through 5f are drawings illustrating steps of a method for manufacturing a barrier corner seal for an electro-optical display according to the subject matter set forth in this specification. FIG. 6 is a schematic cross-sectional cutaway side view illustrating a conventional pinched edge seal applied to an electro-optical display. FIGS. 7a through 7e are schematic cross-sectional views illustrating steps of a method for manufacturing an electro-optical display having an improved pinched edge seal according to the subject matter set forth in this specification. Figure 8 illustrates a graph showing four plots of relative humidity in an electrophoretic medium as a function of distance from the edge of the FPL. Figure 9 illustrates a graph showing four plots of relative humidity in an electrophoretic medium as a function of distance from the edge of the FPL. FIG. 10 is a schematic cross-sectional view illustrating an exemplary embodiment of a variable transparent window comprising a sealed electro-optical display stack according to the subject matter presented in this specification. It should be emphasized that the attached drawings are not to scale and are schematic. In particular, for the sake of ease of illustration, the thicknesses of the various layers in the drawings do not correspond to their actual thicknesses. Additionally, in all drawings, the thicknesses of the various layers are greatly exaggerated with respect to their lateral dimensions. Specific details for implementing the invention

[0059] Flexible electro-optical displays, including rollable ones, particularly those using encapsulated electrophoretic media, offer significant new marketing opportunities; for example, large displays that can be stored in a compact form can be useful as additional display devices on electronic devices that currently only feature small display screens but where large display screens are often useful; examples of such devices include cellular phones equipped to receive email. However, these flexible electro-optical displays will typically require sealing to prevent the ingress of water vapor and other environmental contaminants, which can adversely affect the electro-optical properties or operating life of the display. U.S. Patent Nos. 6,982,178, 7,110,164, and 7,649,674 and Patent Publication No. 2004 / 0155857 all discuss the sealing of electro-optical displays, but most of the displays considered are formed on rigid, glass, or similar backplanes, and additional difficulties arise in selecting a sealing technology suitable for flexible displays. In order to provide proper sealing in a flexible display, both the structural characteristics and barrier characteristics of the sealing material used, as well as the configuration of the final display, need to be carefully considered.

[0060] As discussed in detail below, there are various approaches for sealing flexible displays using combinations of substrates, edge seal materials, and assembly techniques. For the purposes of subsequent discussion, the term “backplane” is used herein to refer to a rigid or flexible material provided with one or more electrodes, consistent with its conventional meaning in the field of electro-optical displays and in the aforementioned patents and published applications. The backplane may also be provided with electronics for addressing the display, or such electronics may be provided in a unit separate from the backplane. In flexible displays, it is highly desirable for the backplane to provide sufficient barrier properties to prevent the chip penetration of moisture and other contaminants through the non-viewing side of the display (the display is, of course, normally viewed from a side far from the backplane). If one or more additional barrier layers need to be added to the backplane to reduce the ingress of moisture and other contaminants, the barrier layers should be positioned as close as possible to the electro-optical layer so that the edge profile of the low barrier material is almost or completely absent between the front (discussed below) and rear barrier layers.

[0061] The term “front substrate” is used herein to refer to a rigid or flexible material that is transparent (and preferably transparent), in accordance with its conventional meaning in the field of electro-optical displays and in the patents and published applications mentioned above. The front substrate will typically comprise at least one electrode, most commonly a single continuous front electrode extending across the entire display. Typically, the exposed surface of the front substrate will form the viewing surface through which an observer views the display, but additional layers may be interposed between the front substrate and the viewing surface, as in some of the embodiments described below. As with the backplane, the front substrate must provide sufficient barrier properties to prevent the penetration of moisture and other contaminants through the viewing side of the display.

[0062] Typically, an electro-optical display includes one or more barrier layers to prevent the ingress of moisture, dust, gas, etc., or to prevent the discharge of fluid within the display. If one or more additional layers need to be added to the front substrate to reduce the ingress of moisture and other contaminants, the barrier layers should be positioned as close as possible to the electro-optical layer so that there is little to no edge profile with respect to the back substrate when the barrier layer is draped over the display.

[0063] As discussed in the aforementioned U.S. Patent Nos. 7,649,674, 6,982,178 and 7,110,164 and Patent Publication No. 2004 / 0155857, a common front substrate for electro-optical displays comprises a thin layer of ITO on PET, and such coated films are commercially readily available, for example, from Saint Gobain. In such front substrates, the ITO layer acts as a barrier material, but in practice, it inevitably suffers from pinholes and cracks, through which moisture and other contaminants can penetrate into the electro-optical material. To increase the sealing properties of such PET / ITO or similar front substrates, it is desirable to laminate a redundant barrier layer onto the front substrate, wherein the redundant barrier layer is a homopolymer (e.g., polychlorotrifluoroethylene available from Honeywell Corporation under the registered trademark "ACLAR") or a sputtered ceramic (e.g., AlO available from Toppan Printing Company under the trade name Toppan GX Film). xIt is formed as ). In other embodiments, flexible glass, such as WILLOW® brand glass from Corning, may be used. To provide a flexible display, the redundant barrier layer should ideally be about 12 mm thin, but can be as thick as 5 mil (127 µm) if sufficient flexibility is still available. If an adhesive layer is required to attach the redundant barrier to the front substrate, the adhesive layer must be transparent, colorless, thin, flexible, have low creep (when the display is bent or rolled), and be durable at all temperatures within the display's operating range. Certain cross-linked polyurethanes and polyacrylates may be used as such adhesives. Suitable optically clear adhesives are commercially available from Norland Adhesives.

[0064] Alternatively, the barrier properties of the PET / ITO or similar forward substrate can be improved by coating a redundant metal oxide layer (e.g., an alumina or zinc oxide layer) on the surface of the forward substrate opposite to the ITO layer or under the ITO layer. The combination of the ITO layer and the redundant metal oxide layer improves the barrier properties of the forward substrate without excessive yellowing of the substrate (e.g., by reducing the movement of water vapor through inevitable cracks and pinholes within the ITO layer), as may occur when attempting to improve barrier properties by increasing the thickness of the ITO layer. Instead of a simple metal oxide layer, a more complex structure comprising ceramic materials, such as Barix (registered trademark) sealing material available from Vitex Systems, Inc., 3047 Orchard Parkway, San Jose, CA 95134, may be used; additionally, the barrier layer may be provided on the surface of the forward substrate away from the ITO layer or under the ITO layer. Vitex Systems currently sells a polymer film with both Barix and ITO layers under the brand name FlexGlass 200, but the polymer film is 5 mil (127 mm) PEN.

[0065] As well as the barrier properties of the front substrate, characteristics such as flexibility, cost, and other specialized properties can also be controlled by the careful selection of both the polymer and the conductive material used in the front substrate. In principle, almost any flexible, light-transmitting polymer can be used; suitable polymers include PET, PEN, polycarbonate, poly(vinylidene chloride) (sold under the trademark "SARAN"), polychlorotrifluoroethylene (sold under the trademarks "ACLAR" and "CLARIS"), triacetyl cellulose, materials sold by JSR Company under the 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 (trademark), carbon nanotubes, and about 10 4 Other suitable conductive light-transmitting conductors having a resistivity of less than ohm / square (transmittance greater than 60%) are included.

[0066] Hereinafter, exemplary embodiments of a display according to the present invention will be described by way of example only with reference to the attached drawings. In all cases, the electro-optical layer may be any of an encapsulated electrophoretic layer, a polymer-dispersed electrophoretic layer, or any of the other types of electro-optical layers discussed above. The display may include one or two lamination adhesive layers to attach the electro-optical material to a front substrate and / or a backplane. The display is visible through the lamination adhesive layer, and the display may be assembled by direct coating and lamination, or by front lamination, inverted front lamination, or the use of a double release film as described in the patents and applications referred to in the "Reference to Related Applications" section of this specification. As previously mentioned, the display is generally visible through the front substrate, but in some cases, a light-transmitting backplane may be used to provide a double-sided display or to operate in the aforementioned shutter mode. This configuration can be used in a variable transmission film, thereby allowing the amount of light transmitted through the film to be electronically changed. In all attached drawings, since the electro-optical display is shown with the viewing surface of the display (or referred to as the front surface) at the top, the front surface and rear surface referred to below refer to the upper surface and lower surface, respectively, as illustrated in the relevant drawings.

[0067] FIG. 1 of the attached drawings is a schematic cross-sectional view illustrating an exemplary embodiment of a sealed electro-optical display (100) according to the subject matter set forth in this specification. In particular, FIG. 1 corresponds to cross section AA identified in FIG. 2d by the cross-sectional plane cutting line (205).

[0068] An electro-optical display (100) typically comprises an upper transparent electrode (110), an electrophoretic medium layer (120), and a lower electrode (130), which often comprises a plurality of pixel electrodes of an active matrix of pixels controlled by thin-film transistors (TFTs). The electrophoretic medium (120) comprises electrophoretic particles (121) and electrophoretic particles (122). The electrophoretic particles (121 and 122) may have different charges and optical properties. For example, the electrophoretic particles (121) may be black and have a positive charge, while the electrophoretic particles (122) may be white and have a negative charge. However, in some embodiments, the electrophoretic medium (120) comprises only a single type of electrophoretic particle, or three or more electrophoretic particles, each of which may have different optical, electro-optical, or chemical properties. The electrophoretic medium (120) typically comprises a non-polar solvent such as isoparaffin, and may also include a dispersed polymer and a charge controller to facilitate state stability, e.g., bistable, that is, the ability to maintain an electro-optical state without inputting any additional energy.

[0069] The electrophoretic medium (120) illustrated in FIG. 1 is partitioned by a plurality of microcapsules (126). However, in some embodiments, the electrophoretic medium (120) is partitioned by the walls of a plurality of microcells (not illustrated in FIG. 1). A structure formed by an upper electrode (110) and an electrophoretic medium layer (120) (also referred to as FPL (125)) is disposed on a substrate (150) which may be rigid or flexible. In some embodiments, the FPL (125) is disposed on a backplane (155) which is an assembly comprising a lower electrode (130) organized as a plurality of pixel electrodes, an array of thin-film transistors (not illustrated in FIG. 1), and the substrate (150). In other embodiments, it should be understood that the lower electrode (130) may be a single electrode, such as a carbon-paste electrode or a metal foil (not illustrated). Additionally, in some embodiments, the lower electrode (130) may be light-transmitting and may be made of the same or similar materials as the upper electrode (110).

[0070] The electro-optical display (100) also typically includes an upper protection or barrier layer (160) for protecting the upper electrode (110) from damage, and a lower protection or barrier layer (161) for protecting the substrate (150) from damage. The upper barrier layer (160) and the lower barrier layer (161), together with edge sealing components discussed in detail below, may surround the entire electro-optical display (100) to prevent water ingress and limit fluctuations in relative humidity within the display. As illustrated in FIG. 1, the upper barrier layer (160) and the lower barrier layer (161) may extend beyond the periphery of the upper electrode (110) and the substrate (150).

[0071] The electro-optical display (100) may also include an adhesive layer (140) between the upper electrode (110) and the upper barrier layer (160), and an adhesive layer (141) between the substrate (150) and the lower barrier layer (161). Although not shown in FIG. 1, the electro-optical display (100) may include one or more additional adhesive layers as needed (e.g., between the upper electrode (110) and the electrophoretic medium layer (120), between the electrophoretic medium layer (120) and the backplane (155)). In some embodiments, the adhesive layer may include an integrated primer component to improve adhesion, or a separate primer layer (not shown in FIG. 1) may be used. (Structures of electrophoretic displays and component parts, pigments, adhesives, electrode materials, etc. are described in numerous patents and patent applications disclosed by E Ink Corporation, such as U.S. 6,922,276; 7,002,728; 7,072,095; 7,116,318; 7,715,088; and 7,839,564, all of which are incorporated herein by reference in their entirety. In some embodiments, barrier layers are manufactured to comprise an integral adhesive material or layer on at least one surface.

[0072] The electro-optical display (100) may also include an edge seal formed by a flexible barrier tape (170) extending along the outer perimeter of the electro-optical display (100). As illustrated in FIG. 1, an adhesive layer (142) attaches the flexible barrier tape (170) to an upper barrier layer (160), and an adhesive layer (143) attaches the flexible barrier tape (170) to a lower barrier layer (161). Although shown as separate layers in FIG. 1, in some embodiments, the barrier tape (170) comprises an outer layer having good barrier properties, and an integrated inner adhesive layer used to secure the barrier tape (170) to the upper and lower barrier layers (160, 161) of the display.

[0073] In some embodiments, the barrier tape (170) has a thickness of about 12 mm, but can be as thick as 0.005 (127 mm). The barrier tape (170) may be formed from materials having good barrier properties, such as a polymer (e.g., a homopolymer such as polychlorotrifluoroethylene or similar materials) or sputtered ceramic on PET, PEN, PC, or other transparent plastics. Alternatively, if transparency is not required, a metal foil such as aluminum may be used. This material is designed to be somewhat flexible, but cracking may occur if it is wrinkled or bent at too severe an angle. Accordingly, the electro-optical display (100) includes a rod (180) positioned adjacent to the outer perimeter of the electro-optical display (100) to contact the barrier tape (170) at the bend point. Thus, the bend radius of the barrier tape (170) can be controlled based on the position and average diameter (185) of the rod (180). There is, and thereby, cracks in the barrier tape (170) are minimized or eliminated.

[0074] In some embodiments, the rod (180) comprises a nylon fiber having an average diameter (185) of about 0.020 (0.508 mm). In some embodiments, the rod (180) has an average diameter (185) between about 0.010 (0.254 mm) and about 0.100 (2.54 mm). Those skilled in the art will recognize that the average diameter (185) of the rod (180) can be set according to the thickness of the electro-optical display (100) and the desired bending radius of the barrier tape (170). The rod (180) may be formed from a material such as a fluorinated organic compound (e.g., fluorocarbon or similar material), a polymer (e.g., nylon, ultra-high molecular weight polyethylene (UHMWPE), high-modulus polyethylene (HMPE), polycarbonate, acrylic, polystyrene, or similar material). In some embodiments, the rod (180) is formed from a glass fiber.

[0075] FIGS. 2a through 2d are cut-down bottom views (e.g., viewed from the opposite side of the observer shown in FIG. 1) illustrating steps of a method for manufacturing an electro-optical display having edge seal components according to the subject matter set forth in this specification. FIG. 2a is a cut-down bottom view (200A) illustrating edge seal components added to an electro-optical display. The electro-optical display shown in FIG. 2a does not yet have any edge seal components (e.g., flexible barrier tape (170), rod (180), adhesive layer (142), and adhesive layer (143)) applied, but is otherwise substantially identical to the electro-optical display (100) described in relation to FIG. 1.

[0076] The upper barrier layer (160) (not shown in FIG. 2a) and the lower barrier layer (161) (and their corresponding adhesive layers if they are separate components) may be sized to overhang each edge of the electro-optical display by an amount substantially equal to the diameter of the rod component to be used to form each edge seal. In some embodiments, oversized sheets of barrier layer material are applied to the upper and lower parts of the electro-optical display (100) and then trimmed to a desired size. In some embodiments, the upper barrier layer (160) and the lower barrier layer (161) are pre-cut to a predetermined size before being applied to the electro-optical display (100). The adhesive layer (142) and the adhesive layer (143) are formulated and applied so that the upper and lower overhanging portions of the barrier material are not bonded together and the upper and lower barrier layers can be attached to the electro-optical display (100), but the adhesive is sufficiently adhesive to hold the load component in place until the load component is permanently fixed in place by the barrier tape, as described in detail below.

[0077] As illustrated in FIG. 2a, a rod (181) is positioned along the outer edge of the electro-optical display (100) between the overhanging portions of the upper barrier layer (160) and the lower barrier layer (161). Before being applied to the electro-optical display (100), the rod (181) may be pre-cut to a predetermined length based on the dimensions of the electro-optical display (100). Alternatively, the rod (181) may be trimmed to a desired length (e.g., substantially the same length as the upper barrier layer (160) and the lower barrier layer (161)) after being applied to the electro-optical display (100) (indicated by trim (291) and dashed lines in FIG. 2a).

[0078] The barrier tape (171) is applied to the upper barrier layer (160) such that the longitudinal midpoint (171c) of the barrier tape (171) is located adjacent to the outer edge of the rod (181). In some embodiments, the barrier tape (171) is applied to the upper barrier layer (160) such that the longitudinal midpoint (171c) is substantially located at or near the vertical midpoint of the rod (181) when the barrier tape (171) is subsequently applied to the lower barrier layer (161) as described below. For example, refer to the location of the longitudinal midpoint (170c) of the rod (180) in FIG. 1.

[0079] As indicated by the arrow (290), the barrier tape (171) is wound around the rod (181) while maintaining close contact with the barrier tape (171) until the barrier tape (171) is then applied to the bottom barrier layer (161). The round shape and diameter of the rod (181) prevent the barrier tape (171) from wrinkling or bending at a radius that could cause the barrier tape (171) to crack during or after application to the electro-optical display. A substantially similar process is used to place the rod (182) and apply the barrier tape (172) to the electro-optical display, so that when the barrier tape (172) is subsequently applied to the bottom barrier layer (161), the longitudinal midpoint (172c) is substantially located at or near the vertical midpoint of the rod (182).

[0080] Although the barrier tape described in the embodiments of this specification is initially applied to the upper barrier layer (160) and then to the lower barrier layer (161), those skilled in the art will recognize that the process of the barrier tape being initially applied to the lower barrier layer (161) is within the scope of this disclosure.

[0081] FIG. 2b is a cutaway bottom view (200B) illustrating an electro-optical display with barrier tape (171) and barrier tape (172) applied. The portions of barrier tape (171) and barrier tape (172) extending beyond the edges of the upper barrier layer (160) and the lower barrier layer (161) may be trimmed as indicated by the trim (292) and dashed lines in FIG. 2b. In some embodiments, barrier tape (171) and barrier tape (172) are pre-cut to a predetermined length based on the dimensions of the electro-optical display (100) and applied so as not to require trimming.

[0082] FIG. 2c is a cutaway bottom view (200C) illustrating a barrier tape (170) applied to an electro-optical display. In a process substantially similar to that described above, a rod (180) is placed between an upper barrier layer (160) and a lower barrier layer (161), and the barrier tape (170) is initially applied to the upper barrier layer (160). However, before wrapping the barrier tape (170) around the rod (180), an edge sealing material (196) is applied to the corners of the electro-optical display. For example, a needle distributor (295) may be used to apply the edge sealing material (196) to the joints where the rods (181 and 182) meet each end of the rod (180).

[0083] The edge sealing material (196) may consist of a distributed sealant (thermal, chemical, and / or radiation-curable type), polyisobutylene, or acrylate-based sealant, etc. In some embodiments, the curable edge sealing material (196) is a UV-curable resin having a low water vapor permeability (WVTR). WVTR is a measure of the water vapor permeability of a given material, i.e., the mass of water vapor passing through a given area of ​​the material at a specific temperature and humidity over a given period. In some embodiments, the edge sealing material (196) has a water vapor permeability of about 0.01 g / m² at 60°C and 100% relative humidity. 2It is a material having a WVTR of less than / day. In some embodiments, the edge sealing material (196) has a g / m² between about 0.01 and about 2 at 60°C and 90% relative humidity. 2 It is a material having a WVTR of 2 to 3 g / m² at 60°C and 90% relative humidity. 2 It has been found that edge sealing materials (196) having a WVTR of 1 / day (e.g., UV500 by HumiSeal, UV A80 by Cemedine Co., Ltd.) can be effective as moisture barriers in some embodiments. It has also been found that hybrid radiation and thermal curing sealants (i.e., thermal post-baked UV curing types) provide specific advantages to display system performance. For example, Threebond 3000 / 3100 series materials (Threebond Corporation, Cincincinnati, OH) have favorable water vapor barrier properties (e.g., low water vapor permeability), low viscosity at elevated temperatures for easy distribution of edge seal materials, good wetting properties, and manageable curing properties. Those skilled in the art and familiar with advanced sealants will be able to identify other sealants that provide similar performance.

[0084] The curable edge sealing material (196) is then cured using a UV irradiation device to create a moisture-proof seal at the corner of the electro-optical display (100) where the rods (181 and 182) meet the ends of the rod (180). As indicated by the arrow (292), the barrier tape (170) is then wrapped around the rod (180) while maintaining close contact with the rod (180) until the barrier tape (170) is applied to the bottom barrier layer (161) (and over the ends of the barrier tape (171) and barrier tape (172). The round shape and diameter of the rod (180) prevent the barrier tape (170) from wrinkling or bending at a radius that could cause the barrier tape (170) to crack while or after it is applied to the electro-optical display.

[0085] Finally, any portion of the barrier tape (170) extending beyond the edges of the upper barrier layer (160) and the lower barrier layer (161) may be trimmed. In some embodiments, the barrier tape (170) is pre-cut to a predetermined length based on the dimensions of the electro-optical display (100) and applied so as not to require trimming. A substantially similar process may be used to add edge seals to other edges of the electro-optical display (not shown in FIG. 2c).

[0086] FIG. 2d is a cutaway bottom view (200D) illustrating an electro-optical display (e.g., electro-optical display (100)) having edge seals according to the techniques and methods described herein. As discussed above, the edge seal components and manufacturing processes of the present invention can minimize or eliminate cracking of the barrier tape material, thereby advantageously preventing moisture and contaminants from penetrating into the electro-optical material and other components of the electro-optical display. These edge seals can provide performance equivalent to or better than conventional liquid-dispensed edge seals, which are more time-consuming and difficult to implement, as well as more difficult to scale for large-scale production runs, because the edge sealing liquid must be dispensed around the perimeter of each electro-optical display and then cured. In contrast, using the edge sealing technologies and techniques described in this specification allows many components to be prepared in advance and significantly reduces curing time because only a small amount of curable edge sealing material is used for each electro-optical display.

[0087] Additionally, the edge seal technology described herein significantly reduces the width of the barrier material around the periphery of the finished electro-optical display compared to an electro-optical display employing a conventional pinched edge seal (e.g., Fig. 2 of the aforementioned U.S. Patent No. 7,649,674 and Fig. 4 of U.S. Patent Application Publication No. 2020 / 0032081) formed by pinching and bonding the overhanging upper and lower barrier layer materials together. Conventional pinched edge seals can add more than 15 mm of width at each edge of the electro-optical display. Accordingly, the outer boundary region or bezel portion of the housing for a display including an electro-optical display created using the edge seal technology described herein can be made significantly narrower than the bezel of a display including an electro-optical display having a conventional pinched edge seal. Accordingly, for a display housing of a given size, a display incorporating an electro-optical display having the edge seal technology of the present invention described herein may have a larger visible area than a display incorporating a conventional pinched edge seal electro-optical display. The edge seal technology of the present invention described herein also increases the scalability of display applications by enabling the configuration of composite displays composed of multiple individual electro-optical displays arranged as close as possible in a tiled configuration. For example, the reduced width of the perimeter barrier material allows the individual electro-optical display sections to be positioned sufficiently close to each other so that the composite display provides the appearance of a seamless single screen.

[0088] In an alternative embodiment, a continuous section of rod material is wrapped around the entire perimeter of the electro-optical display. The material used for the rod member is selected so that the rod member is not deformed or damaged by the bending radius required to route the rod member around each corner of the display. Additionally, a continuous section of barrier tape is used to seal the edges of the display. This embodiment advantageously eliminates manufacturing steps such as individually sizing and cutting each section of the rod member and barrier tape. It also eliminates the need for UV-curable edge sealing material at each corner because the barrier tape is a continuous length material without voids or openings at the corners.

[0089] FIG. 3 is a schematic cross-section (300) of an adhesive barrier tape (370) having an integral rod (380) according to the subject matter set forth in this specification. The barrier tape (370) may be formed from a material substantially similar to the barrier tape described above and may include an adhesive layer (342) coating at least one side of the tape and an integral rod (380) extending the length of the barrier tape (370). The rod (380) may be positioned substantially along the longitudinal center of the barrier tape (370).

[0090] FIG. 4 is a schematic cross-sectional cutaway illustrating an exemplary embodiment of a sealed electro-optical display (400) comprising an adhesive barrier tape (370) having an integrated rod (380) according to the subject matter set forth in this specification. The barrier tape (370) may be applied to the edge of the electro-optical display such that the integrated rod (380) is substantially in direct contact with the edge of the electro-optical display (100). The barrier tape (370) may then be folded and trimmed to the same size as before or pre-cut to a desired length. A curable edge sealing material may be applied as described above to seal the corners of the electro-optical display (400).

[0091] The electro-optical display (400) provides all the advantages of the electro-optical display (100) described above, and provides additional advantages that the barrier tape (370) reduces the number of manufacturing steps required to manufacture the electro-optical display, particularly those steps that typically must be performed manually. The speed of the manufacturing process is also greatly improved. For example, an entire sheet or roll of electro-optical display material can be coated with upper and lower barrier layers in a single operation, and individual electro-optical displays of desired dimensions can then be cut from the larger sheet. Thus, when using the barrier tape (370), there is no need to apply the upper and lower barrier layers to the electro-optical display in a second operation after the electro-optical display is cut from the larger sheet, and then trim the oversized sheets of barrier layer material so that they overhang each edge of the electro-optical display by an amount substantially equal to the diameter of the rod.

[0092] In an alternative embodiment, a continuous portion of the barrier tape (370) is wrapped around the entire perimeter of the electro-optical display. The material used for the rod member is selected so that the rod member is not deformed or damaged by the bending radius required to route the rod member around each corner of the display. This embodiment advantageously eliminates manufacturing steps such as individually sizing and cutting each section of the barrier tape. It also eliminates the need for UV-curable edge sealing material at each corner because the barrier tape is a continuous length of material without voids or openings at the corners.

[0093] Some electro-optical display applications can benefit from additional useful features apart from the excellent moisture barrier properties of the edge seal components described above. For example, variable transparency films for architectural applications are often applied to the exterior surfaces of existing glass windows to save significant time and cost during installation. These films are commonly exposed to extreme temperature fluctuations, moisture, and mechanical stress due to changing weather conditions.

[0094] Variable transparency window films for architectural applications can also be sealed between glass plates inside the window during manufacturing to better protect and insulate the film. However, the film can still be exposed to similar temperature fluctuations and mechanical stresses experienced by building structures, such as vibration and bending. Additionally, the various materials used for variable transparency window films, glass panes, window frames, and other structural components typically have significantly different properties (e.g., coefficient of thermal expansion, elastic modulus, etc.) and can therefore physically change at different rates (e.g., expansion / contraction, bending, twisting, etc.) in response to changing environmental conditions.

[0095] Accordingly, the edge seal technology described herein may include additional features that provide the additional durability and protection necessary to make such applications feasible in harsher environments. For example, in some embodiments, the inner surface of the edge sealing barrier tape applied to the upper and lower barrier layers of an electro-optical display (e.g., upper barrier layer (160) and lower barrier layer (161)) comprises a layer of silver electrical insulating material.

[0096] The insulating material prevents the electrodes (e.g., upper electrode (110) and lower electrode (130)) from short-circuiting to each other and to other components within the structure or housing where the electro-optical display (100) may be installed. Additionally, the edge-sealing barrier tape described herein can protect different layers of the electro-optical display (100) from peeling off at their edges during handling and final-use installation. This advantageously allows the electro-optical display (100) to be produced using a roll-to-roll process without requiring an additional lamination step to add a protection and / or barrier layer after parts are cut from a roll of finished display material. For example, conventional manufacturing techniques require that each part of the display material cut from a roll be laminated piece by piece, which is a time-consuming process and is prone to introducing defects into the display, particularly in the visible area. In contrast, using the edge sealing barrier tape described herein, a device manufacturer can simply cut a piece of display film from a roll, apply electrical connections to the film electrodes as needed, and wrap the edges with barrier tape in preparation for final installation in a building structure or product housing.

[0097] In some embodiments, the barrier tape is manufactured as a multilayer stack of materials having different properties based on the environmental conditions to which they will be exposed. In some embodiments, the barrier tape comprises a barrier material on a surface to be exposed to an external environment (e.g., metal foil or similar material) and an insulating material on a surface to be applied to barrier layers of an electro-optical display (e.g., polyimide or similar material). In some embodiments, the barrier tape is a ceramic-coated PET film. In some embodiments, the barrier tape is manufactured as a single multifunctional film from a material having both barrier and insulating properties.

[0098] Additionally, the configuration of the edge-sealing barrier tape described herein may be modified according to the specific application of the finished electro-optical display. In some embodiments, the barrier tape is manufactured such that a first portion of its outer surface comprises a first material and a second portion of its outer surface comprises a second material having properties different from those of the first material. For example, referring to FIG. 1, the electro-optical display (100) may be a variable transparent window film applied to the outer surface of an existing glass window. The barrier tape (170) may be manufactured such that substantially half of its outer surface comprises a first material and substantially half of its outer surface comprises a second material having properties different from those of the first material. For example, the outer surface of the barrier tape (170) may be longitudinally distributed into substantially equal halves, such as an adhesive portion (170a) on the first half and a barrier portion (170b) on the second half. The adhesive portion (170a) may include an adhesive or other bonding agent to facilitate the application of the electro-optical display (100) to the window glass. The outer-facing barrier portion (170b) may include a wear-resistant or weather-resistant material to provide added durability to the electro-optical display (100).

[0099] In some embodiments, the electro-optical display (100) is intended to be used as a freestanding device, and the entire outer surface of the barrier tape (170) is abrasion-resistant but does not contain adhesive. In some embodiments, the barrier tape (170) contains a coloring agent (e.g., a dye, a pigment, or other material used for coloring). In some embodiments, the barrier tape (170) is provided in any one of various colors to enable color-matching to an architectural structure or product housing on which the electro-optical display (100) is installed on or within it.

[0100] FIG. 10 is a schematic cross-sectional view illustrating an exemplary embodiment of a variable transparent window (1000) comprising a sealed electro-optical display stack according to the subject matter set forth in this specification. The variable transparent window (1000) typically comprises an upper transparent electrode (1010), an electrophoretic medium layer (1020), and a lower transparent electrode (1030). The upper transparent electrode (1010) and the lower transparent electrode (1030) are light-transmitting electrically conductive layers and may each comprise a continuous planar layer of electrically conductive material. Alternatively, one or both of the upper transparent electrode (1010) and the lower transparent electrode (1030) may comprise a plurality of individually addressable pixel electrodes controlled by thin-film transistors (TFTs).

[0101] The electrophoretic medium (1020) comprises a plurality of electrophoretic particles (1021). The electrophoretic particles (1021) may have different charges and different optical properties. In some embodiments, the electrophoretic particles (1021) are black and have a positive charge. In some embodiments, the electrophoretic particles (1021) are white and have a negative charge. In some embodiments, the electrophoretic medium (1020) comprises only a single type of electrophoretic particle, or three or more electrophoretic particles, each of which may have different optical, electro-optical, or chemical properties.

[0102] The electrophoretic medium (1020) illustrated in FIG. 10 is partitioned into a plurality of microcells by walls (1027). However, in some embodiments, the electrophoretic medium (1020) is partitioned by a plurality of microcapsules similar to the electro-optical display (100) of FIG. 1. A protrusion structure (1028) is formed in each microcell. The protrusion structure (1028) may include various geometric shapes. In this example, the protrusion structure (1028) is a cone on a cylinder. The protrusion structure (1028) has a protrusion bottom, a protrusion wall surface, a protrusion apex, and a protrusion height. The protrusion apex is a point or set of points of the protrusion structure (1028) that has a shorter distance from the microcell opening than all other points of the protrusion structure (1028). In some embodiments, the walls (1027) and the protrusion structure (1028) are formed of a polymer material as discussed in the patents and publications referenced above.

[0103] In the example of the microcell in FIG. 10, the vertex of the protrusion structure (1028) is the vertex of a cone. The protrusion height is the distance between the bottom of the protrusion and the vertex of the protrusion. If the protrusion structure (1028) has a vertex that includes more than one point such as a flat surface, the protrusion height is the distance between the flat surface and the base of the bottom of the protrusion.

[0104] Microcells are sealed by a sealing layer (1012), which may be, for example, a UV-cured fluoropolymer. In some embodiments, the sealing layer (1012) is a hydrophilic polymer that is incompatible with the fluid in the electrophoretic medium (1020). Examples of components used in the sealing composition for the sealing layer (1012) may include, but are not limited to, thermoplastic or thermosetting materials and their precursors. Specific examples may include materials such as monofunctional acrylate, monofunctional methacrylate, polyfunctional acrylate, polyfunctional methacrylate, polyvinyl alcohol, polyacrylic acid, cellulose, gelatin, etc. Additives such as polymer binders or thickeners, photoinitiators, catalysts, vulcanizing agents, fillers, colorants, or surfactants may be added to the sealing composition to improve physicomechanical properties and the optical collimation film.

[0105] The sealing composition may be a water-soluble polymer having water as a sealing solvent. Examples of suitable water-soluble polymers or water-soluble polymer precursors include polyvinyl alcohol; polyethylene glycol, copolymers thereof with polypropylene glycol, and derivatives thereof, e.g., PEG-PPG-PEG, PPG-PEG, PPG-PEG-PPG; poly(vinylpyrrolidone) and copolymers thereof, e.g., poly(vinylpyrrolidone) / vinyl acetate (PVP / VA); polysaccharides such as cellulose and its derivatives, poly(glucosamine), dextran, guar gum, and starch; gelatin; melamine-formaldehyde; poly(acrylic acid), its salt form and copolymer; poly(methacrylic acid), its salt form and copolymer; poly(maleic acid), its salt form and copolymer; poly(2-dimethylaminoethyl methacrylate); poly(2-ethyl-2-oxazoline); poly(2-vinylpyridine); The sealing material may include, but is not limited to, cationic polymers functionalized with quaternary ammonium groups such as poly(allylamine); polyacrylamide; polyethyleneimine; polymethacrylamide; poly(sodium styrene sulfonate); poly(2-methacryloxyethyltrimethylammonium bromide); and poly(allylamine hydrochloride). The sealing material may also include a water-dispersible polymer with water as a formulation solvent. Examples of suitable polymer water dispersants may include polyurethane water dispersants and latex water dispersants. Suitable latexes in water dispersants include polyacrylates, polyvinyl acetates and their copolymers, e.g., ethylene vinyl acetate, and polystyrene copolymers, e.g., polystyrene butadiene and polystyrene / acrylate.

[0106] The variable transparent window (1000) includes a protective or barrier layer (1060) to protect the upper electrode (1010) from damage. An adhesive layer (1040), which is a first adhesive layer, is placed between the upper electrode (1010) and the barrier layer (1060). The barrier layer (1060), together with an edge sealing component described in detail below, substantially surrounds the entire surface of the variable transparent window (1000) to prevent water ingress and limit changes in relative humidity within the structure of the variable transparent window (1000).

[0107] For example, examples of additional components that may be present in the adhesive composition may include, but are not limited to, acrylic, styrene-butadiene copolymer, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, polyvinyl butyral, cellulose acetate butyrate, polyvinylpyrrolidone, polyurethane, polyamide, ethylene-vinyl acetate copolymer, epoxide, polyfunctional acrylate, vinyl, vinyl ether, and their oligomers, polymers, and copolymers. The adhesive layers may also include, polyvinyl alcohol; copolymers thereof with polyethylene glycol and polypropylene glycol; poly(vinylpyrrolidone) and copolymers thereof; polysaccharides; gelatin; poly(acrylic acid), its salt form and copolymers thereof; poly(methacrylic acid), its salt form and copolymers thereof; poly(2-dimethylaminoethyl methacrylate); poly(2-ethyl-2-oxazoline); It may also include a polyurethane dispersant selected from the group consisting of poly(2-vinylpyridine); poly(allylamine); polyacrylamide; polymethacrylamide; and cationic polymers functionalized with quaternary ammonium groups, and a water-soluble polymer. The adhesive layers may be post-cured, for example, by heat or radiation such as UV after lamination.

[0108] In some embodiments, the adhesive layer may include an integrated primer component to improve adhesion, or a separate primer layer (not shown in FIG. 10) may be used. (Structures of electrophoretic displays and component parts, pigments, adhesives, electrode materials, etc. are described in numerous patents and patent applications disclosed by E Ink Corporation, such as U.S. 6,922,276; 7,002,728; 7,072,095; 7,116,318; 7,715,088; and 7,839,564, all of which are incorporated herein by reference in their entirety. In some embodiments, barrier layers are manufactured to comprise an integral adhesive material or layer on at least one surface.)

[0109] A display stack structure comprising a barrier layer (1060), an adhesive layer (1040), an upper transparent electrode (1010), microcells (1020) sealed with an electrophoretic medium, and a lower transparent electrode (1030) can be applied to a substrate (1050). A second adhesive layer, an adhesive layer (1041), adheres the display stack to the substrate (1050). In some embodiments, the display stack is laminated to the substrate (1050).

[0110] The substrate (1050) may be a material used to form the window pane. The substrate (1050) may be a type of glass, e.g., clear float glass, tinted / colored glass, solar glass (i.e., infrared absorbing / reflecting glass), self-cleaning glass (e.g., Pilkington Activ), low-reflectivity glass (e.g., Pilkington Optiview), high-grade thin glass (e.g., Pilkington Microfloat), high optical purity glass (e.g., Pilkington Optiwhite), or a multilayer structure formed from a number of types of glass materials. An example of solar glass is green glass that has a visible light transmittance of 75% (or more) and absorbs about 35% of infrared light in the wavelength band of 0.9 to 1.3 microns. The substrate (1050) may also be any glass, polycarbonate, acrylic, or other suitable transparent sheet used to form the window pane.

[0111] The variable transparent window (1000) may also include an edge seal formed by an edge sealing material or a flexible barrier tape (1070) extending along the outer circumference of the variable transparent window (1000). The edge seal serves to prevent the ingress of moisture and other contaminants around the outer edge of the variable transparent window (1000). As illustrated in FIG. 10, a third adhesive layer, i.e., an adhesive layer (1042), adheres a first horizontal section of the flexible barrier tape (1070) to a portion of the upper part of the barrier layer (1060), a vertical section of the flexible barrier tape (1070) to the outer vertical edges of the layers constituting the display stack, and a second horizontal section of the flexible barrier tape (1070) to the surface of the substrate (1050). Although shown as separate layers in FIG. 10, in some embodiments, the barrier tape (1070) comprises an outer layer having good barrier properties and an integrated inner adhesive layer used to fix the barrier tape (1070) to the layers constituting the display stack and the substrate (1050).

[0112] When operated, when an electric field is applied between the upper transparent electrode (1010) and the lower transparent electrode (1030) through a first voltage waveform, the electrically charged electrophoretic particle (1021) moves toward the lower transparent electrode (1030) and is directed toward the channels on both sides of the protruding structure (1028) by the inclination of the conical portion of the protruding structure (1028). The positioning of the electrophoretic particle (1021) within the channels results in an open or transparent state of the variable transparent window (1000). The two leftmost microcells shown in FIG. 10 are examples of the positions of the electrophoretic particle (1021) when the variable transparent window (1000) is in an open state.

[0113] To transition from an open state to an opaque or closed state, the application of an electric field between the upper transparent electrode (1010) and the lower transparent electrode (1030) through a second voltage waveform causes the movement of electrically charged electrophoretic particles (1021) toward the upper transparent electrode (1010) at a second speed. The three far right microcells shown in FIG. 10 are examples of the positions of the electrophoretic particles (1021) when the variable transparent window (1000) is in a closed or opaque state. In FIG. 10, showing the two far left microcells in an open state while simultaneously showing the three far right microcells in a closed state is merely to illustrate the pigment shuttering mechanism. In the case of a variable transparent window (1000) comprising a single upper transparent electrode (1010) and a single lower transparent electrode (1030), all microcells will typically be in the same state.

[0114] Note that it is also necessary to impart some lateral velocity component when moving the electrophoretic particles (1021). Otherwise, they simply move upward, that is, only in the vertical direction, and do not move laterally from the starting position of the channel. In this scenario (no lateral direction), the closed state will not be effectively formed because the closed state will have a relatively high light transmittance. Induced-charge electroosmosis ("ICEO") can be used to provide this motion. For example, fluid is induced by electrolytic motion around the electrophoretic particles (1021) having a higher percentage of light transmittance than the closed optical state, and as a result, the fluid is attracted toward the electrophoretic particles (1021) at the poles and discharged at the equator. Because other electrophoretic particles (1021) may be mixed into the fluid, and because the electrophoretic particles (1021) may have different sizes and thus experience different sizes of ICEO velocities, at appropriately high applied fields (typically greater than 1 V / micrometer) and low frequencies (typically in the range of 10 to 1000 Hz AC), chaotic motion of the particles may be induced, which causes scrambling of the location even if the particles are originally concentrated in one area.

[0115] A variable transparent window formed by the structure of the variable transparent window (1000) may be less expensive to manufacture than a display stack that includes barrier layers at the top and bottom. For example, such a variable transparent window can be manufactured using fewer layers because a bottom barrier layer and a corresponding adhesive layer are not required, and a lamination adhesive layer is not required between the sealing layer and the top transparent electrode. This also reduces the number of steps required to manufacture the display stack. Additionally, the omission of these layers makes the variable transparent window thinner overall and increases its light transmittance. Furthermore, the product quality and manufacturing yield of the variable transparent window (1000) are higher because the barrier layer (1060) can be applied to the display stack in a roll-to-roll manufacturing process, in contrast to when the display stack is applied in a secondary lamination process after being bonded to the substrate (1050).

[0116] As discussed above, conventional dispensed thermosetting edge seals can be time-consuming to apply and cure to the periphery of an electro-optical display. The aforementioned edge sealing barrier tape improves upon conventional dispensed edge seals by, in part, eliminating the use of dispensed edge sealing liquid at all corners of the electro-optical display except for the corners where barrier tape segments on adjacent display edges meet.

[0117] FIGS. 5a through 5f illustrate additional aspects of the edge seal technology of the present invention described herein and related manufacturing technology that completely eliminate the use of distributed thermosetting barrier materials requiring curing. In particular, a barrier seal is described that may be formed of a flexible barrier material and positioned at each corner of an electro-optical display to seal the corners without using a curable edge sealing material.

[0118] FIG. 5a is a diagram (500a) illustrating steps of a method for manufacturing a corner barrier seal (501) for an electro-optical display according to the subject matter set forth in this specification. FIG. 5a illustrates a top view of a corner barrier seal (501) of a substantially square sheet (501) of barrier material. The corner barrier seal (501) can be trimmed to remove sections (502) (indicated by trim (591) and dashed lines in FIG. 5a), resulting in an X-shaped piece of barrier material.

[0119] In some embodiments, the corner barrier seal (501) is a metal foil formed from a ductile sheet metal such as annealed aluminum or tin. In some embodiments, the corner barrier seal (501) is coated with a plastic film or laminated to a plastic film to make the plastic film non-conductive and also protect the metal from mechanical damage. In some embodiments, the corner barrier seal (501) is formed from a material similar to the barrier tape or barrier layer described above.

[0120] In some embodiments, the corner barrier seal (501) is formed from a substantially square material having sides each having a length of about 5 mm to about 50 mm. In some embodiments, the corner barrier seal (501) is formed from ceramic-coated PET having a net thickness of, for example, about 12 µm to about 127 µm. In some embodiments, the corner barrier seal (501) is formed from an aluminum foil-type material having a thickness of about 6 µm to 50 µm, but thicker materials can be used with a metal forming tool capable of working with thicker metal materials.

[0121] The corner barrier seal (501) can be trimmed manually by hand or through a mechanized process such as an automated die or laser cutting. In some embodiments, a first cutting process is used to cut a square of barrier material from a roll or larger sheet material, and a second different cutting process is used to remove a section (502) from the corner barrier seal (501).

[0122] FIG. 5b is a diagram (500b) illustrating additional steps of a method for manufacturing a corner barrier seal (501) for an electro-optical display according to the subject matter set forth in this specification. FIG. 5b illustrates a top view of the current X-shaped corner barrier seal (501) with section (502) removed. The corner barrier seal (501) is folded or creased at each of the fold portions (503, 504a, 504b) (fold portions (504a) and (504b) are collectively referred to as "fold portions (504)") and then unfolded into its original shape. The fold portions (503 and 504) divide the upper surface of the corner barrier seal (501) into individual faces (AF) that meet at the intersection (506).

[0123] FIG. 5c is a drawing (500c) illustrating a corrugated corner barrier seal (501) at a fold (503). As indicated by the arrow (592), the fold (503) is a so-called "valley fold" formed such that the side of the corner barrier seal (501) is folded upward at the fold (503) until the upper surfaces of faces A, B, and C meet the upper surfaces of faces D, E, and F. After forming the fold (503), the corner barrier seal (501) is unfolded back to its original shape.

[0124] FIG. 5d is a drawing (500d) illustrating a corrugated corner barrier seal (501) at a fold portion (504a). As indicated by the arrow (593), the fold portion (504a) is a so-called "mountain fold" formed such that the corner barrier seal (501) is folded at the fold portion (504b) until the bottom surfaces of faces B, C, and D meet the bottom surfaces of faces A, E, and F. After forming the fold portion (504a), the corner barrier seal (501) is unfolded into its original shape. Subsequently, the fold portion (504b) is formed such that the corner barrier seal (501) is folded at the fold portion (504b) until the bottom surfaces of faces A, B, and F meet the bottom surfaces of faces D, D, and E (not shown in FIG. 5d). After creating the fold (504b), the corner barrier seal (501) is unfolded back to its original shape.

[0125] Although the folds have been described in a specific order in this specification, those skilled in the art will understand that the folds (503, 504a, 504b) can be manufactured in any order without changing the final configuration of the corner barrier seal (501).

[0126] The corner barrier seal (501) can be folded manually by hand or through a mechanized process such as a press die. In some embodiments, a combination of mechanized folding and hand folding is used to create the folds (503, 504a, and 504b).

[0127] FIG. 5e is an isometric view (500e) illustrating a corner barrier seal (501) for an electro-optical display after performing additional steps of a manufacturing method according to the subject matter set forth in this specification. As previously described, the corner barrier seal (501) is unfolded into its original shape after each fold (503, 504a, 504b) is manufactured. To achieve the configuration of the corner barrier seal (501) illustrated in FIG. 5e, the fold (503, 504a, 504b) are simultaneously refolded along the same fold line to form two corner pockets: a first corner pocket formed between surfaces A, B and C, and a second corner pocket formed between surfaces D, E and F.

[0128] Once the corner barrier seal (501) is prepared as described above, it can be applied to the corners of the electro-optical display. In one embodiment, the front laminate is first laminated to the backplane, and the resulting structure is cut to the desired display size. The corner barrier seal (501) can then be placed at each corner of the display. In some embodiments, each corner of the display laminate is pushed into one of two corner pockets of the corner barrier seal (501). In some embodiments, the inner faces of the corner barrier seal (501) (Fig. 5e, faces A, C, D, and F) can be pushed or fitted between the front laminate and the backplane so that the corner of the front laminate is received in the corner pocket formed between faces A, B, and C, and the corner of the backplane is received between the corner pockets formed between faces D, E, and F.

[0129] FIG. 5f is an equiangular view (500F) of an electro-optical display (500) having corner barrier seals (501) positioned at each corner. In some embodiments, the corner barrier seals (501) do not require any adhesive to be permanently fixed in place because they are covered by upper and lower barrier layers that are subsequently laminated to the upper and lower surfaces of the electro-optical display (500). Subsequently, a taped edge seal, such as the flexible barrier tapes mentioned above, can be applied to each edge of the electro-optical display (500). Alternatively, the corner barrier seal (501) allows conventional pinched edge seals to still be used by sizing the upper and lower barrier layers so as to extend beyond the edges of the display and the corner barrier seal (501) as needed.

[0130] In some embodiments, corner barrier seals (501) are formed with an adhesive on the lower side of the barrier material so that the inner surfaces of the corner pockets can be bonded to the corners of the electro-optical display. This allows the corner barrier seals (501) to be applied to the corners of the electro-optical display after lamination of the upper barrier layer and the lower barrier layer, and then a taped edge seal, such as the flexible barrier tapes described above, can be used to complete the edge sealing process. This configuration may be advantageous for electro-optical displays using ITO for the upper and lower electrodes, which are common in architectural applications. For example, the upper and lower barrier layers can be roll-to-roll laminated onto the electro-optical display, thereby minimizing the lamination steps per unit. A corner barrier seal (501) with adhesive effectively seals the corners of the upper and lower barrier layer surfaces without UV-curable resin, and a flexible barrier tape is attached to all surfaces of the corner barrier seal (501) and any exposed upper and lower barrier layer materials to form a comprehensive edge seal around the entire electro-optical display.

[0131] Accordingly, the corner barrier seal (501) described in relation to FIGS. 5a through 5f offers several advantages over conventional corner seal components and sealing processes. For example, the corner barrier seal (501) allows a superior moisture barrier seal to be formed at all points around the perimeter of the electro-optical display and reduces the required width of the barrier material at the edges of the finished electro-optical display, thereby resulting in an increase in the active and viewing areas of the electro-optical display compared to an electro-optical display using a conventional pinched edge seal. Additionally, the corner barrier seal (501), made of a ductile sheet metal such as annealed aluminum or tin, can be manufactured to be thinner but mechanically more rigid than the sputtered oxide-type barrier film typically used in conventional edge seals.

[0132] Integrating a corner barrier seal (501) into the edge sealing process for an electro-optical display also reduces the various materials and equipment required for the manufacturing process. For example, using a corner barrier seal (501) eliminates the need for materials and equipment related to dispensing thermosetting barrier materials at the corners of the display, and likewise eliminates the need for a UV curing system. A corner edge seal (501) is also useful when the display is configured at an installation location (i.e., in the field) and it is not possible to cut the edge bead, wrap the edge, and cure it as described above in relation to FIGS. 1 through 4.

[0133] Using the corner barrier seal (501) disclosed in this specification can also reduce manufacturing time. For example, the corner barrier seal (501) may be formed separately from and prior to other components of the electro-optical display, and may even be a piece supplied from a third party. Thus, the corner barrier seal (501) may be a stock part that is kept in bulk within the inventory of the manufacturing operation and withdrawn as needed during display production. Additionally, the corner barrier seal (501) allows the electro-optical display assembly operation to be scaled more easily because the manufacturing process is not bottlenecked by the use of specialized equipment, such as UV curing stations, which may be in high demand and short supply on the manufacturing floor. This allows any number of assembly technicians to work in parallel with applying the corner barrier seals (501) to in-process electro-optical displays on the manufacturing floor.

[0134] Finally, similar to the barrier tape described above, the corner barrier seal (501) may be provided in any one of various colors to make the corner pieces visually less conspicuous. For example, a corner barrier seal made of metal foil may have a color film or paint applied to one surface to match more closely with the color of the product housing or architectural structure on which the electro-optical display is installed.

[0135] In some embodiments, the section (502) is not removed from the corner barrier seal (501) as described above in relation to FIG. 5a. In this embodiment, the finished corner barrier seal (501) covers a larger portion of the active area of ​​the display, but it is advantageous to allow the barrier seal (501) to be manufactured from a simplified and easy-to-form shape, such as a square.

[0136] Other types of conventional edge seals can be formed by pinch-sealing an upper barrier layer on the surface of a backplane substrate. For example, to form the edge seals incorporated in FIG. 3 of U.S. Patent No. 7,649,674 summarized above, peripheral portions of a barrier sheet that extend or "overhang" the outer edges of a display laminate are "pinch-down" onto other layers of the display and sealed to the peripheral portions of the backplane.

[0137] FIG. 6 is a schematic cross-sectional cut-side view (600) illustrating a conventional pinched edge seal applied to an electro-optical display. In FIG. 6, the FPL (625) is laminated to the backplane (655), and an overhang portion of the upper barrier layer (660) is attached to the surface of the backplane (655) to form a pinched edge seal. Dimensions A-F identify the dimensions of specific areas of the electro-optical display associated with the pitched edge seal.

[0138] Dimension A refers to a portion of electro-optical material that is typically set to black and remains unchanged during operation to provide a sharp black border around the perimeter of the display within a viewing area (e.g., immediately adjacent to or overlapping with the inner edges of the display bezel).

[0139] Dimension B represents the width of the boundary portion of the FPL that is left unused or undriven during the operation of the electro-optical display (e.g., no voltage is applied to alter the optical state of the electro-optical medium in the area of ​​dimension B). One reason for leaving this area unused is to account for any damage that structures near the edges of the FPL might suffer when cut from a larger sheet material, and / or any defects in the FPL at the edges of the larger sheet. For example, microcells within the electro-optical medium may be cut or incomplete at the edges, as can the walls surrounding microcapsules. A combination of the areas indicated by dimensions A and B may be referred to as the inactive area of ​​the FPL because that area cannot be used to actively display images.

[0140] When a pinched edge seal is applied, an air gap (662) is typically created between the upper barrier layer (660) and the surface of the backplane (655). Dimension C identifies the width of the air gap (662) on the surface of the backplane (655). Dimension D indicates the width of the portion of the upper barrier layer (660) attached to the surface of the backplane (655). In some embodiments, a pressure-sensitive adhesive is used to bond the upper barrier layer (660) to the surface of the backplane (655). Finally, Dimension E indicates the width of the area on the surface of the backplane (655) between the end of the upper barrier layer (660) and the outer edge of the backplane (655).

[0141] Electro-optical displays including such pinched edge seals typically have adequate moisture diffusion protection at the surface of the display, but relatively weak moisture diffusion protection at the edges. As mentioned above in the discussion of conventional pinched edge seals, the areas where pinched portions of the barrier sheet are adhered to the surface of the backplane may be moisture diffusion paths at the edges of the electro-optical display. It has been observed that the pressure-sensitive adhesive used to attach the upper barrier layer (660) to the surface of the backplane (655) may be a primary moisture diffusion path along the edges of the electro-optical display.

[0142] Measures to reduce or mitigate the effects of edge moisture diffusion include increasing the width of the inactive area by increasing dimensions A and / or dimensions B, and / or increasing the width of dimension D. These measures can effectively increase the distance any moisture must travel into or out of the electro-optical display and narrow the path before it can negatively affect the performance of the areas of the electro-optical display that are actively used to display images. The air within the air gap (662) also provides a measure of protection against moisture diffusion.

[0143] While these measures can improve the level of protection against moisture diffusion at the edges of the electro-optical display, increasing the width of any of the dimensions described above generally conflicts with design goals to reduce the width of the bezel covering the parts of the display indicated by dimensions A through E and / or to reduce the overall dimensions of the display housing.

[0144] The pinched edge seal of the present invention described below includes features that resolve the defects of conventional pinched edge seals. In particular, a pinched edge seal comprising a low WVTR UV-curable resin that fills an area where an air gap (e.g., air gap (662)) would otherwise be created during the formation of a conventional pinched edge seal, and a corresponding process for manufacturing the same are described.

[0145] FIGS. 7a through 7e are schematic cross-sectional views (700A through 700E) illustrating steps of a method for manufacturing an electro-optical display having an enhanced pinched edge seal according to the subject matter set forth in this specification.

[0146] FIG. 7a is a schematic cross-sectional view (700A) illustrating steps of a method for manufacturing an electro-optical display having an enhanced pinched edge seal. In FIG. 7a, the FPL (725) is laminated onto the surface of a backplane (755) comprising a substantially transparent substrate and electrodes. However, those skilled in the art will recognize that an electro-optical display comprising a backplane (755) formed of opaque materials is within the scope of the present disclosure.

[0147] FIG. 7b is a schematic cross-sectional view (700B) illustrating steps of a method for manufacturing an electro-optical display having an enhanced pinched edge seal. In FIG. 7b, a distributor (795) can be used to apply an edge sealing material (796) around the perimeter of an FPL (725). In some embodiments, the distributor (795) is a volumetric fluid dispensing system capable of controlling the pressure and speed at which the edge sealing material (796) is dispensed to apply a constant volume of edge sealing material (796) around the FPL (725).

[0148] In some embodiments, the edge sealing material (796) is about 0.0001 g / m² at 60°C and 90% relative humidity. 2It is a material having a WVTR of less than / day. In some embodiments, the edge sealing material (796) has a g / m² between about 0.0001 and about 0.01 at 60°C and 90-100% relative humidity. 2 It is a material having a WVTR of / day. In some embodiments, the edge sealing material (796) has a g / m² between about 0.01 and about 2 at 60°C and 90% relative humidity. 2 It is a material having a WVTR of 1 / day. 2 to 3 g / m² at 60°C and 90% relative humidity. 2 It has been found that an edge sealing material (796) having a WVTR of 1 / day (e.g., UV500 by HumiSeal, UV A80 by Cemedine Co., Ltd.) can be effective as a moisture barrier in some embodiments.

[0149] FIG. 7c is a schematic cross-sectional view (700C) illustrating steps of a method for manufacturing an electro-optical display having an enhanced pinched edge seal. In FIG. 7c, a UV irradiation device or other curing system is used to partially cure the edge sealing material (796) (indicated by arrow (794)), so that it is no longer free-flowing but remains flexible and pliable. In some embodiments, the edge sealing material (796) is cured for about 25 seconds. In some embodiments, the edge sealing material (796) is cured for about 15 to 40 seconds. FIG. 7c illustrates that curing is performed from both the top and bottom of the edge sealing material (796), but curing of the edge sealing material (796) may be performed from the top and / or bottom, provided that the backplane (755) is formed of UV-transparent materials.

[0150] FIG. 7d is a schematic cross-sectional view (700D) illustrating steps of a method for manufacturing an electro-optical display having an enhanced pinched edge seal. In FIG. 7d, an upper barrier layer (760) is laminated over an FPL (725) and a partially cured edge sealing material (796). The malleable edge sealing material (796) flows sufficiently to fill a space that would typically become an air gap (e.g., FIG. 6, air gap (662)).

[0151] FIG. 7e is a schematic cross-sectional view (700E) illustrating steps of a method for manufacturing an electro-optical display having an enhanced pinched edge seal. In FIG. 7e, a UV irradiation device or other curing system is used to fully cure the edge sealing material (796) (indicated by arrow (794)). In some embodiments, the edge sealing material (796) is cured for more than 60 seconds. The pinched portion of the barrier layer (760) is also adhered to the surface of the backplane (755). FIG. 7e illustrates that curing is performed from both the top and bottom of the edge sealing material (796), but curing of the edge sealing material (796) may be performed from the top and / or bottom if the top barrier layer (760) and the backplane (755) are formed of UV-transparent materials.

[0152] The upper barrier layer (760) illustrated in FIGS. 7d ​​and 7e is depicted as a continuous layer of material. However, it should be noted that a process substantially similar to the one described in connection with FIGS. 7a through 7e can be used to create an enhanced pinched edge seal using a barrier tape applied around the perimeter of the display stack after it has been laminated to the substrate. For example, this process can be used to form an enhanced pinched edge seal for the variable transparent window (1000) described in connection with FIG. 10.

[0153] Incorporating the enhanced pinched edge seals described herein reduces the effects of edge moisture diffusion and improves overall moisture protection of the electro-optical display. FIGS. 8 and 9 are graphs illustrating the results of simulations performed using a verified COMSOL moisture transport model for an electro-optical display including conventional and enhanced pinched edge seals.

[0154] FIG. 8 illustrates a graph (800) illustrating four plots of relative humidity in an electrophoretic medium as a function of distance from the edge of the FPL. Line plot (805ag) represents a simulated edge moisture profile of an electro-optical display including a conventional pinched edge seal with an air gap operated for 5 days in an environment with an ambient temperature of 70°C and a relative humidity of 23%. Line plot (805uv) represents a simulated edge moisture profile of an electro-optical display including an enhanced pinched edge seal for the same period under the same environmental conditions. Line plot (810ag) represents a simulated edge moisture profile of an electro-optical display including a conventional pinched edge seal with an air gap operated for 10 days in an environment with an ambient temperature of 70°C and a relative humidity of 23%. The line plot (810uv) shows the simulated edge moisture profile of an electro-optical display including enhanced pinched edge seals for the same period under the same conditions.

[0155] As illustrated in Fig. 8, the improved pinched edge seal outperforms conventional edge seals during 5- and 10-day periods and reduces the drop in relative humidity experienced by the FPL near the edge. This results in more consistent electro-optical performance across the entire surface of the display. This also increases the durability of the displays, particularly when subjected to harsh conditions such as being outdoors and experiencing large temperature swings (e.g., displays used for bus stop timetables).

[0156] FIG. 9 illustrates a graph (900) illustrating four plots of relative humidity in an electrophoretic medium as a function of distance from the edge of the FPL. Line plot (905ag) represents a simulated edge moisture profile of an electro-optical display including a conventional pinched edge seal with an air gap operated for 5 days in an environment with an ambient temperature of 70°C and a relative humidity of 23%. For line plot (905ag), dimension C (Fig. 6) is 1 mm and dimension D (Fig. 6) is 2.16 mm. Line plot (905uv) represents a simulated edge moisture profile of an electro-optical display including an enhanced pinched edge seal for the same period under the same environmental conditions. For line plot (905uv), dimension C (Fig. 6) is also 1 mm, but dimension D (Fig. 6) is reduced to 1.5 mm.

[0157] Similarly, line plot (910ag) shows a simulated edge moisture profile of an electro-optical display including a conventional pinched edge seal with an air gap operated for 10 days in an environment with an ambient temperature of 70°C and a relative humidity of 23%. For line plot (910ag), dimension C (Fig. 6) is 1 mm and dimension D (Fig. 6) is 2.16 mm. Line plot (910uv) shows a simulated edge moisture profile of an electro-optical display including an enhanced pinched edge seal for the same period under the same environmental conditions. For line plot (910uv), dimension C (Fig. 6) is also 1 mm, but dimension D (Fig. 6) is reduced to 1.5 mm.

[0158] The plot in FIG. 9 illustrates that the improved pinched edge seal design provides improved edge moisture diffusion performance compared to the conventional air gap edge seal design, even when the dimension D is reduced. Accordingly, the outer boundary region or bezel portion of the housing for a display including an electro-optical display created using the improved pinched edge seal technology described herein can be made significantly narrower than the bezel of a display including an electro-optical display having a conventional pinched edge seal. Thus, for a display housing of a given size, a display incorporating an electro-optical display having the improved pinched edge seal technology described herein can have a larger visible area or a smaller display housing than a display incorporating a conventional pinched edge seal electro-optical display.

[0159] The enhanced pinched edge seal described herein includes features that provide enhanced protection against moisture diffusion at the display edges while maintaining or reducing the dimensions of the inactive and unused portions of the display at the edges. For example, the cured edge sealing material (796) of the enhanced pinched edge seal forms a superior moisture barrier compared to the air present in the conventional pinched edge seal, thereby reducing the dimensions of the inactive and / or unused edge portions of the display. Additionally, the partial curing step of the process of the present invention ensures that the UV-curable edge sealing material (796) is not so viscous as to seep over or between the layers of the FPL (725) and remains flexible before the upper barrier layer (760) is applied to the FPL (725). This step also ensures that the edge sealing material (796) does not dry too quickly to form a problematic hard mass of UV resin larger than the FPL (725), or shrink to leave an air gap after curing. Thus, the partially cured edge sealing material (796) can conform to and fill the space where the air gap under the pinched edge seal will normally be.

[0160] The electrode arrangement in the various types of displays of the present invention may be any type described in the aforementioned E Ink and MIT patents and applications. Thus, for example, displays may be of a direct drive type in which a plurality of electrodes are provided on a backplane, and each of the plurality of electrodes is provided with a separate connector by a controller capable of controlling the voltage applied to a specific electrode. In such direct drive displays, although other front electrode arrangements are possible, a single continuous front electrode covering the entire display is generally provided. Depending on the type of electro-optical material used, it may be possible to use a passive matrix drive arrangement in which (typically) the backplane carries a plurality of elongated parallel electrodes ("column electrodes"), while a plurality of elongated parallel electrodes ("row electrodes") are provided on the opposite side of the electro-optical material at right angles to the column electrodes, and the overlap between one specific column electrode and one specific row electrode defines one pixel of the display. The displays of the present invention may also be of an active matrix type having a matrix of pixel electrodes on a backplane and a single continuous front electrode covering the entire display, each pixel electrode defining a pixel of the display and having an associated transistor or other non-linear element, and the active matrix display is scanned in a conventional manner to record the display row by row. Finally, the display may also be of a stylus-driven type having a single electrode on the backplane and not having a permanent front electrode, and recording of the display is achieved by moving a stylus across the front surface of the display.

[0161] Although the edge seal and sealing technology of the present invention is described primarily in relation to electrophoretic displays, those skilled in the art will understand that the edge seal and sealing technology of the present invention is highly applicable to other electro-optical display technologies. Thus, for example, the present invention can be used to manufacture edge seals for use with liquid crystal displays and organic light-emitting diode ("OLED") displays used in e-book readers, portable computers, tablet computers, cellular phones, smart cards, signage, watches, electronic shelf labels, and flash drives.

[0162] It will be obvious to those skilled in the art that numerous changes and modifications may be made to the specific embodiments of the invention described above without departing from the scope of the invention. Accordingly, the entire foregoing description should be interpreted in an illustrative sense rather than a limiting one.

Claims

Claim 1 An electro-optical display comprising: a backplane comprising at least one electrode; a layer of an electro-optical material disposed adjacent to the backplane; a light-transmitting electrically conductive layer disposed opposite to the layer of the electro-optical material from the backplane; and a corner barrier seal disposed at each corner of the electro-optical display, wherein the corner barrier seal comprises a barrier material having a square shape in an unfolded state; first, second, and third fold lines, wherein the first and second fold lines are perpendicular to each other and the third fold line is substantially 45 degrees from the first and second fold lines, and the first, second, and third fold lines divide each other and the barrier material; and wherein the first and second fold lines are folded upward and the third fold line is folded downward to form first and second corner pockets. Claim 2 An electro-optical display according to claim 1, further comprising the step of forming a square-shaped barrier material into an X-shape in the unfolded state. Claim 3 The electro-optical display according to claim 1, wherein the corner barrier seal further comprises an adhesive layer disposed on the inner surface of the first and second corner pockets. Claim 4 An electro-optical display according to claim 1, wherein the layer of the electro-optical material and the light-transmitting electrically conductive layer are disposed within the first corner pocket of each corner barrier seal, and the backplane is disposed within the second corner pocket of each corner barrier seal. Claim 5 An electro-optical display according to claim 1, wherein the layer of the electro-optical material, the light-transmitting electrically conductive layer, and the backplane are disposed within the first corner pocket or the second corner pocket of each corner barrier seal. Claim 6 An electro-optical display according to claim 1, further comprising: a first barrier layer disposed on a first surface of the light-transmitting electrically-conductive layer and each corner barrier seal; and a second barrier layer disposed on a second surface of the backplane and each corner barrier seal. Claim 7 In claim 6, the first and second barrier layers are larger in dimensions than the light-transmitting electrical-conducting layer, the layer of the electro-optical material, and the backplane, so as to leave peripheral portions of the first and second barrier layers extending beyond each of the edges of the light-transmitting electrical-conducting layer, the layer of the electro-optical material, and the backplane, and the peripheral portions of the first and second barrier layers are fixed to each other to seal the edges of the electro-optical display. Claim 8 An electro-optical display according to claim 6, further comprising an edge sealing component extending around the periphery of the electro-optical display over the edge portion of the first barrier layer and the edge portion of the second barrier layer. Claim 9 In claim 8, the edge sealing component is an electro-optical display comprising a barrier tape containing polychlorotrifluoroethylene or aluminum oxide. Claim 10 A method for forming an electro-optical display, comprising: providing a front laminate comprising a layer of electro-optical material and a light-transmitting electrically conductive layer; providing a backplane comprising at least one pixel electrode, wherein the backplane has length and width dimensions greater than those of a front sub-assembly; laminating the front sub-assembly to the backplane; distributing a curable edge seal material around a periphery of the backplane adjacent to the outer edges of the front sub-assembly; partially curing the curable edge seal material; laminating a barrier layer over the front sub-assembly and the partially cured edge seal material, wherein the barrier layer is sized to overhang the partially cured edge seal material; and bonding the overhang portion of the barrier layer to the surface of the backplane. A method for forming an electro-optical display, comprising the step of completely curing the curable edge seal material. Claim 11 A method for forming an electro-optical display according to claim 10, wherein the surface of the barrier layer comprises a layer of pressure-sensitive adhesive. Claim 12 A method for forming an electro-optical display, wherein, in claim 10, the step of partially curing the curable edge seal material comprises the step of curing the curable edge seal material for 15 to 40 seconds. Claim 13 In claim 10, the above-mentioned curable edge seal material is 2 to 3 g / m² at 60°C and 90% relative humidity. 2 A method for forming an electro-optical display having a water vapor transmittance of / day. Claim 14 A method for forming an electro-optical display, wherein the curable edge seal material is a polymer comprising epoxy, urethane, acrylate, or a combination thereof, in claim 10. Claim 15 In claim 10, the above-mentioned curable edge seal material is UV-curable, a method for forming an electro-optical display. Claim 16 Electro-optical display formed using the method of claim 10.

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