Electro-optical device comprising identification mark

Abstract

The invention discloses an electro-optical device including an identification mark. An electro-optical device includes, in order, a conductive light-transmitting layer, an electro-optical material layer, an adhesive layer, and a backplane substrate including a plurality of pixel electrodes configured to apply an electric potential between the conductive light-transmitting layer and the pixel electrodes. Comprising an identification mark is located in a layer of the electro-optical device and emits radiation of a characteristic wavelength when activated by a stimulus, enabling identification of manufacturing sources and manufacturing batches of the electro-optical device and its components. The techniques also relate to front plane laminates and dual release sheets, which are useful components for manufacturing electro-optical devices.

Description

[0001] Related applications This application is a divisional application of the patent application with application number 202080059339.2 filed on February 22, 2022 and invention name “Electro-optical device comprising an identification mark”.

[0002] This application claims priority to U.S. Provisional Application No. 62 / 891,486, filed on August 26, 2019, which is incorporated herein by reference in its entirety. Technical Field

[0003] The present invention relates to an electro-optical device comprising an activation region having an identification mark which, when activated, emits radiation of a characteristic wavelength. The present invention enables verification of the manufacturing origin of the electro-optical device and its components and identification of the manufacturing batch of the electro-optical device and its components at any time during the life of the electro-optical device. Background Art

[0004] The term "electro-optical," as applied to a material, device, or display, is used herein in its conventional sense in the field of imaging, referring to a material having first and second display states that differ in at least one optical property, wherein the material is caused to change from its first display state to its second display state by applying an electric field to the material. While the optical property is typically color perceptible to the human eye, it may be another optical property, such as light transmission, reflection, luminescence, or, in the case of displays intended for machine reading, false color in the sense of a change in reflectivity at electromagnetic wavelengths outside the visible range. Hereinafter, the terms "electro-optical device" and "electro-optical display" are used interchangeably and are considered synonyms.

[0005] The term "gray state" is used herein in its conventional sense in the field of imaging to refer to a state between the two extreme optical states of a pixel, and does not necessarily imply a black and white transition between the two extreme states. For example, several patents and published applications of Iink Corporation referred to below describe electrophoretic displays in which the extreme states are white and dark blue, so that the intermediate "gray state" is actually light blue. In fact, as already mentioned, the change in optical state may not be a color change at all. The terms "black" and "white" may be used below to refer to the two extreme optical states of the display, and should be understood to generally include extreme optical states that are not strictly black and white, such as the white and dark blue states mentioned above. The term "monochromatic" may be used below to refer to a drive scheme in which the pixel is driven only to its two extreme optical states, without an intermediate gray state.

[0006] Certain electro-optic materials are solid in the sense that they have a solid outer surface, although they may, and often do, have internal spaces filled with liquid or gas. For convenience, displays using such solid-state electro-optic materials may be referred to hereinafter as "solid-state electro-optic displays" or "solid-state electro-optic devices." Thus, the terms "solid-state electro-optic display" or "solid-state electro-optic device" include rotating two-color component displays, packaged electrophoretic displays, microcell electrophoretic displays, and packaged liquid crystal displays.

[0007] The terms "bistable" and "bistability" are used herein in their conventional sense in the art to refer to a display including display elements having first and second display states that differ in at least one optical property such that, after any given element is driven to assume its first or second display state with an addressing pulse of finite duration, that state persists, after termination of the addressing pulse, for a time that is 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. As shown in U.S. Patent No. 7,170,670, some particle-based electrophoretic displays supporting grayscale are stable not only in their extreme black and white states but also in intermediate gray states, as are some other types of electro-optical displays. Such displays are properly referred to as "multistable" rather than bistable, but for convenience, the term "bistable" will be used herein to encompass both bistable and multistable displays.

[0008] Several types of electro-optical displays are known. One type of electro-optical display is a rotating two-color component type, as described in, for example, 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 (although this type of display is commonly referred to as a "rotating two-color ball" display, the term "rotating two-color component" is preferably more accurate because, in some of the above-mentioned patents, the rotating component is not spherical). This display uses many small bodies (usually spherical or cylindrical) and internal dipoles, and the body includes two or more parts with different optical properties. These bodies are suspended in a liquid-filled vacuole in the matrix, and the vacuole is filled with liquid so that the body can rotate freely. The appearance of the display is changed by applying an electric field to the display, thereby rotating the body to various positions and changing which part of the body is seen through the viewing surface. This type of electro-optical medium is typically bistable.

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

[0010] Another type of electro-optical display is the electrowetting display developed by Philips and described in Hayes, RA et al., "Video-Speed ​​Electronic Paper Based on Electrowetting", Nature, 425, 383-385 (2003). It is shown in U.S. Patent No. 7,420,549 that such an electrowetting display can be made bistable.

[0011] One type of electro-optical display that has been the subject of intensive research and development for many years is the particle-based electrophoretic display (EPD), in which multiple charged particles move through a fluid under the influence of an electric field. Compared to liquid crystal displays (LCDs), EPDs can offer good brightness and contrast, wide viewing angles, state bistability, and low power consumption. However, issues with the long-term image quality of these displays have hindered their widespread adoption. For example, the particles that make up EPDs tend to settle, resulting in a short lifespan for these displays.

[0012] As mentioned above, electrophoretic media require the presence of a fluid. In most prior art electrophoretic media, the fluid is a liquid, but electrophoretic media can be generated using a gaseous fluid; see, for example, Kitamura, T. et al., “Electronic toner movement for electronic paper-like display,” IDW Japan, 2001, Paper HCS 1-1, and Yamaguchi, Y. et al., “Toner display using insulative particles charged triboelectrically,” IDW Japan, 2001, Paper AMD4-4. See also U.S. Patents No. 7,321,459 and 7,236,291. When such gas-based electrophoretic media are used in an orientation that allows particle sedimentation, such as in signs where the media is arranged in a vertical plane, such gas-based electrophoretic media are susceptible to the same type of problems as liquid-based electrophoretic media due to the same particle sedimentation. In fact, the particle sedimentation problem is more severe in gas-based electrophoretic media than in liquid-based electrophoretic media because the lower viscosity of the gaseous suspending fluid compared to liquids allows for faster sedimentation of the electrophoretic particles.

[0013] Numerous patents and applications assigned to or in the names of the Massachusetts Institute of Technology (MIT), Iink Corporation, Iink California LLC, and related companies describe various technologies for encapsulated and microcell electrophoretic and other electro-optical media. Encapsulated electrophoretic media comprise a plurality of small capsules, each of which itself comprises an inner phase containing electrophoretically mobile particles in a fluid medium and a capsule wall surrounding the inner phase. Typically, the capsules themselves are held in a polymer binder to form a coherent layer between two electrodes. In microcell electrophoretic displays, the charged particles and fluid are not encapsulated within microcapsules, but rather within a plurality of cavities formed within a carrier medium (usually a polymer film). The technologies described in these patents and applications include: (a) Electrophoretic particles, fluids, and fluid additives; see, for example, U.S. Patent Nos. 7,002,728 and 7,679,814; (b) capsules, adhesives, and encapsulation processes; see, e.g., U.S. Patent Nos. 6,922,276 and 7,411,719; (c) microcell structures, wall materials, and methods of forming microcells; see, for example, U.S. Patent Nos. 7,072,095 and 9,279,906; (d) Methods for filling and sealing microlocations; see, e.g., U.S. Patent Nos. 7,144,942 and 7,715,088; (e) Films and subassemblies containing electro-optical materials; see, for example, U.S. Patent Nos. 6,982,178 and 7,839,564; (f) Backsheets, adhesive layers, and other auxiliary layers and methods for use in displays; see, e.g., U.S. Patent Nos. 7,116,318 and 7,535,624; (g) color formation and color adjustment; see, e.g., U.S. Patent Nos. 7,075,502 and 7,839,564; (h) Methods for driving displays; see, for example, U.S. Patent Nos. 7,012,600 and 7,453,445; (i) Display applications; see, e.g., U.S. Patent Nos. 7,312,784 and 8,009,348; and (i) Non-electrophoretic displays, such as described in U.S. Patent No. 6,241,921 and U.S. Patent Application Publication No. 2015 / 0277160; and applications of packaging and microcell technology other than displays; see, for example, U.S. Patent Application Publication Nos. 2015 / 0005720 and 2016 / 0012710.

[0014] Many of the aforementioned patents and applications recognize that the walls surrounding discrete microcapsules in an encapsulated electrophoretic medium can be replaced by a continuous phase, thereby creating a so-called polymer-dispersed electrophoretic display, wherein the electrophoretic medium comprises a plurality of discrete droplets of an electrophoretic fluid and a continuous phase of a polymer material, and wherein the discrete droplets of electrophoretic fluid within such a polymer-dispersed electrophoretic display can be considered to be capsules or microcapsules, even though no discrete capsule membrane is associated with each individual droplet; see, e.g., U.S. Patent No. 6,866,760. Therefore, for the purposes of this application, such polymer-dispersed electrophoretic media are considered to be a subclass of encapsulated electrophoretic media.

[0015] While electrophoretic media are typically opaque (because, for example, in many electrophoretic media, the particles substantially block visible light from being transmitted through the display) and operate in a reflective mode, many electrophoretic displays can be made to operate in a so-called "shutter mode," in which one display state is substantially opaque and one display state is light-transmissive. See, for example, U.S. Patents Nos. 5,872,552, 6,130,774, 6,144,361, 6,172,798, 6,271,823, 6,225,971, and 6,184,856. Dielectrophoretic displays, which are similar to electrophoretic displays but rely on variations in electric field strength, can operate in a similar mode; see U.S. Patent No. 4,418,346. Other types of electro-optical displays can also operate in a shutter mode. Electro-optical media operating in shutter mode can be used in multilayer structures for full-color displays; in this structure, at least one layer adjacent to the viewing surface of the display is operated in shutter mode to expose or hide a second layer further away from the viewing surface.

[0016] Encapsulated electrophoretic displays are generally free of the aggregation and sedimentation failure modes of conventional electrophoretic devices and offer additional benefits, such as the ability to print or coat the display on a variety of flexible and rigid substrates. The term "printing" is intended to encompass all forms of printing and coating, including but not limited to: pre-metered coating such as patch die coating, slot or extrusion coating, slide or lamination coating, and curtain coating; roll coating such as blade-over-roll coating, forward and reverse roll coating; gravure coating; dip coating; spray coating; meniscus coating; spin coating; brush coating; air knife coating; screen printing processes; electrostatic printing processes; thermal printing processes; inkjet printing processes; electrophoretic deposition (see U.S. Patent No. 7,339,715); and other similar techniques. Thus, the resulting display can be flexible. Furthermore, because the display medium can be printed (using a variety of methods), the display itself can be inexpensively manufactured.

[0017] Other types of electro-optical materials may also be used in the present invention. Of particular interest are bistable ferroelectric liquid crystal displays (FLCs), which are known in the art.

[0018] Other types of electro-optical media may also be used in the displays of the present invention.

[0019] An electro-optical device typically comprises a layer of electrophoretic material and at least two other layers arranged on opposite sides of the electrophoretic material, one of the two layers being an electrode layer. In most such devices, both layers are electrode layers, and one or both of the electrode layers are patterned to define the pixels of the display. For example, one electrode layer may be patterned as elongated row electrodes, while the other electrode layer may be patterned as elongated column electrodes extending at right angles to the row electrodes, the pixels being defined by the intersections of the row and column electrodes. Alternatively, and more typically, one electrode layer has the form of a single continuous electrode, while the other electrode layer is patterned as a matrix of pixel electrodes, each pixel electrode defining one pixel of the display. In another type of electrophoretic display intended for use with a stylus, printhead or similar movable electrode that is separate from the display, only one of the layers adjacent to the electrophoretic layer includes an electrode, and the layer on the opposite side of the electrophoretic layer is typically a protective layer intended to prevent the movable electrode from damaging the electrophoretic layer.

[0020] The manufacture of three-layer electrophoretic displays typically involves at least one lamination operation. For example, the aforementioned MIT and Iink patents and applications describe a process for manufacturing encapsulated electrophoretic displays, in which an encapsulated electrophoretic medium, comprising capsules enclosed in a binder, is applied to a flexible substrate comprising an indium tin oxide (ITO) or similar conductive coating on a plastic film (which serves as one electrode in the final display). The capsule / binder coating is dried to form a coherent layer of electrophoretic medium firmly adhered to the substrate. Separately, a backplane is prepared containing an array of pixel electrodes and an appropriate arrangement of conductors connecting the pixel electrodes to the drive circuitry. To form the final display, the substrate with the capsule / binder layer is laminated to the backplane using a laminating adhesive. A very similar process can be used to manufacture electrophoretic displays for use with a stylus or similar movable electrode, by replacing the backplane with a simple protective layer, such as a plastic film, over which the stylus or other movable electrode can slide. In a preferred form of this process, the backplane itself is flexible and is prepared by printing the pixel electrodes and conductors on a plastic film or other flexible substrate. The obvious lamination technique for mass production of displays by this process is roll lamination using a laminating adhesive.

[0021] The aforementioned U.S. Patent No. 6,982,178 describes a method for assembling solid-state electro-optical displays (including encapsulated electrophoretic displays) that is well-suited for mass production. Essentially, the patent describes a so-called "front plane laminate" ("FPL") comprising, in order: (a) a light-transmitting conductive layer; (b) a solid electro-optic layer; (c) an adhesive layer; and (d) a release film. Typically, the light-transmitting conductive layer will be carried on a light-transmitting substrate, which is preferably flexible, in the sense that it can be manually wound onto a roll (for example) 10 inches (254 mm) in diameter without permanent deformation. The term "light-transmitting" is used in the patent and herein to mean that the designated layer transmits sufficient light to enable an observer to observe changes in the display state of the electro-optic medium through the layer, which would typically be observed through the conductive layer and the adjacent substrate (if present); in the case of an electro-optic medium displaying changes in reflectivity at non-visible wavelengths, the term "light-transmitting" should of course be interpreted as referring to transmission of the relevant non-visible wavelengths. The substrate is typically a polymer film and will typically have a thickness of about 1 to about 25 mils (25 to 634 m), preferably from about 2 to about 10 mils (51 to 254 The conductive layer is conveniently a thin metal or metal oxide layer such as aluminum or ITO, or may be a conductive polymer. Polyethylene terephthalate (PET) films coated with aluminum or ITO are commercially available, for example as "aluminized Mylar" ("Mylar" is a registered trademark) from E.I. DuPont de Nemours and Company, Wilmington, Delaware, and such commercial materials can be used to good effect in front plane laminates.

[0022] U.S. Patent No. 7,561,324 describes a so-called "double release sheet" which is essentially a simplified version of the frontplane laminate of the aforementioned U.S. Patent No. 6,982,178. One form of the double release sheet comprises a solid electro-optical medium layer sandwiched between two adhesive layers, one or both of which are covered by a release film. Another form of the double release sheet comprises a solid electro-optical medium layer sandwiched between two release films. Both forms of double release sheet are intended to be used in a process generally similar to the process already described for assembling electro-optic displays from frontplane laminates, but involving two separate laminations; typically, in a first lamination, the double release sheet is laminated to the front electrode to form the front subassembly, and then in a second lamination, the front subassembly is laminated to the backplane to form the final display, although the order of the two laminations can be reversed if desired.

[0023] U.S. Patent No. 7,839,564 describes a so-called "inverted front plane laminate," which is a variation of the front plane laminate described in the aforementioned U.S. Patent No. 6,982,178. The inverted front plane laminate comprises, in sequence, at least one of a light-transmissive protective layer and a light-transmissive conductive layer, an adhesive layer, a solid electro-optic medium layer, and a release film. The inverted front plane laminate is used to form an electro-optic display having a laminated adhesive layer between the electro-optic layer and the front electrode or front substrate; a second, typically thinner, adhesive layer may or may not be present between the electro-optic layer and the backplane. Such an electro-optic display can combine good resolution with good low-temperature performance.

[0024] Light modulators represent a potentially significant market for electro-optical media. As energy performance in buildings and vehicles becomes increasingly important, electro-optical media can be used as coatings on windows (including skylights and sunroofs) to enable the proportion of incident radiation transmitted through the windows to be electronically controlled by varying the optical state of the electro-optical media. Effective implementation of this "variable transmittance" ("VT") technology in buildings is expected to provide the following benefits: (1) reduction of unwanted heating during hot weather, thereby reducing the energy required for cooling, the size of air conditioning equipment, and peak electricity demand; (2) increased use of natural light, thereby reducing energy used for lighting and peak electricity demand; and (3) increased occupant comfort by increasing thermal and visual comfort. Even greater benefits are expected in automobiles, where the ratio of glass surface to enclosed volume is significantly greater than in typical buildings. Specifically, effective implementation of VT technology in automobiles is expected to provide not only the benefits mentioned above, but also the following: (1) improved driving safety, (2) reduced glare, (3) enhanced mirror performance (through the use of electro-optical coatings on mirrors), and (4) improved ability to use head-up displays. Other potential applications of VT technology include privacy glass and glare protection in electronic devices.

[0025] The term "impulse" is used here in its conventional sense, namely, the integral of voltage with respect to time. However, some bistable electro-optical media function as charge converters, and for such media, an alternative definition of impulse may be used, namely, the integral of current with respect to time (which is equal to the total applied charge). Depending on whether the medium functions as a voltage-to-time impulse converter or a charge-to-impulse converter, the appropriate definition of impulse should be used.

[0026] Another complication in driving electrophoretic displays is the need for so-called "DC balancing." As discussed in U.S. Patent Nos. 6,531,997 and 6,504,524, problems can arise, and if the method used to drive the display does not result in a zero or near-zero net time-averaged applied electric field across the electro-optic medium, the operating life of the display is shortened. Driving methods that do achieve a zero net time-averaged applied electric field across the electro-optic medium are conveniently referred to as "direct current balancing" or "DC balancing."

[0027] As already noted, encapsulated electrophoretic media typically consist of electrophoretic capsules disposed in a polymer binder that serves to form the discrete capsules into a coherent layer. The continuous phase in polymer-dispersed electrophoretic media plays a similar role to the cell walls of microcellular media. Yiink researchers have discovered that the specific binder material used in electrophoretic media can influence the electro-optical properties of the media. Among the electro-optical properties of electrophoretic media affected by binder selection is the so-called "dwelling time dependence," as discussed in U.S. Patent No. 7,119,772 (see, in particular, FIG. 34 and the associated description). It has been found that, at least in certain circumstances, the impulse required to transition between two specific optical states in a bistable electrophoretic display varies with the dwell time of the pixel in its initial optical state, a phenomenon known as "dwelling time dependence" or "DTD." Obviously, minimizing the DTD is desirable because it affects the difficulty of driving the display and can affect the quality of the resulting image; for example, DTD can cause pixels that should form a uniform gray area to have slightly different grayscale levels from one another, and the human eye is very sensitive to such variations. Although it is known that the choice of binder affects the DTD, the selection of an appropriate binder for any particular electrophoretic medium has heretofore been based on trial and error, with little understanding of the relationship between the DTD and the binder chemistry.

[0028] U.S. Patent Application Publication No. 2005 / 0107564 describes an aqueous polyurethane dispersion comprising a polyurethane polymer comprising the reaction product of: (a) an isocyanate-terminated prepolymer comprising the reaction product of: (i) at least one polyisocyanate comprising The invention relates to a polyurethane dispersion comprising: (i) tetramethylxylene diisocyanate (scientific name: 1,3-bis(1-isocyanato-1-methylethyl)benzene; hereinafter referred to as "TMXDI"); (ii) at least one difunctional polyol comprising polypropylene glycol; and (iii) an isocyanate-reactive compound comprising an acidic functional group and at least two isocyanate-reactive groups selected from hydroxyl groups, primary amino groups, secondary amino groups, and combinations thereof; (b) a neutralizing agent comprising a tertiary amino group; (c) a monofunctional chain terminator; (d) a segment extender comprising an organic diamine; and (e) water. It has been found that this polyurethane dispersion (hereinafter referred to as a "TMXDI / PPO" dispersion) is useful as a laminating adhesive in electro-optical displays.

[0029] The following discussion focuses on methods for driving one or more pixels of an electro-optical display through a transition from an initial grayscale to a final grayscale (which may be different from or the same as the initial grayscale). The term "waveform" will be used to refer to the overall voltage versus time curve used to achieve the transition from a particular initial grayscale to a particular final grayscale. Typically, such a waveform will include multiple waveform elements, where these elements are substantially rectangular (i.e., where a given element comprises a constant voltage applied over a period of time); elements may be referred to as "pulses" or "drive pulses." The term "drive scheme" refers to a set of waveforms sufficient to achieve all possible transitions between grayscales for a particular display. A display may utilize more than one drive scheme; for example, the aforementioned U.S. Patent No. 7,012,600 teaches that the drive scheme may need to be modified based on parameters such as the display's temperature or the amount of time it has been in operation during its lifetime, and thus a display may be provided with multiple different drive schemes for use at different temperatures, etc. A set of drive schemes used in this manner may be referred to as a "set of related drive schemes." As described in the aforementioned "Methods for driving displays" application, it is also possible to use more than one drive scheme simultaneously in different areas of the same display, and a set of drive schemes used in this way may be referred to as a "set of simultaneous drive schemes".

[0030] One need in the field of electronic devices is to identify the manufacturing origin and batch of such devices and their components in order to troubleshoot and resolve quality issues at any time during the life of the device. The present invention seeks to provide suitable tools to meet this need in an efficient and effective manner. Summary of the Invention

[0031] Thus, in one aspect, the present invention provides an electro-optical device comprising, in sequence, (a) a conductive light-transmitting layer, (b) a layer of electro-optical material, (c) an adhesive layer, and (d) a backplane substrate comprising a plurality of pixel electrodes, wherein the plurality of pixel electrodes are configured to apply an electric potential between the conductive light-transmitting layer and the pixel electrodes, wherein the electro-optical device comprises an activation region having an identification mark that emits radiation having a characteristic wavelength profile when stimulated to activate, and wherein the activation region is located within or adjacent to a layer of the electro-optical device.

[0032] In another aspect, the present invention provides a front plane laminate comprising, in order, (a) a conductive light-transmitting layer, (b) a layer of electro-optical material, (c) an adhesive layer, and (d) a release film, wherein the front plane laminate comprises an activation area having an identification mark that emits radiation of a characteristic wavelength profile when activated by a stimulus, wherein the activation area is located within or adjacent to a layer of the front plane laminate.

[0033] In another aspect, the present invention provides a double release sheet for making an electro-optical device, comprising, in sequence, (a) a first release film, (b) a first adhesive layer, (c) a layer of electro-optical material, (d) an adhesive layer, and a second release film, wherein the double release sheet includes an activation area having an identification mark that emits radiation of a characteristic wavelength profile when activated by a stimulus, and wherein the activation area is located within or adjacent to one layer of the double release sheet.

[0034] In another aspect, the present invention provides a method for authenticating an electro-optical device and any component thereof, comprising the steps of (a) providing an electro-optical device, the electro-optical device comprising, in sequence, a conductive light-transmitting layer, a layer of electro-optical material, an adhesive layer, and a backplane substrate comprising a plurality of pixel electrodes, the plurality of pixel electrodes being configured to apply an electric potential between the conductive light-transmitting layer and the pixel electrodes, wherein the electro-optical device comprises an activation region having an identification mark, the identification mark emitting radiation of a characteristic wavelength profile when activated, and wherein the activation region is located within or adjacent to a layer of the electro-optical device, (b) activating the identification mark by stimulation, (c) detecting the emitted electromagnetic radiation caused by the identification mark, and (d) determining the authenticity of the device or any component thereof or determining the manufacturing batch of the electro-optical device or any component thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Attached Figure 1A and 1B is an illustration of an example of an electro-optical device having identifying indicia in an adhesive layer. An example of steps in a process for making such a device from a front plane laminate is graphically depicted.

[0036] Attached Figures 2A to 2Eis an illustration of another example of an electro-optical device having identifying indicia in the adhesive layer. An example of steps in a process for making such a device from a double release adhesive sheet is graphically depicted.

[0037] Figure 3A 、 3B 3C is a diagram of an electro-optical device having an active region that is a coating on a backplane substrate. An example of the different steps of a process for making such a device from a front plane laminate is graphically depicted.

[0038] Figure 4 is a diagram of an electro-optical device having an electrophoretic medium comprising charged particles as identification marks.

[0039] Figure 5 is a diagram of an electro-optical device having a microencapsulated electrophoretic medium. The shell of the microcapsule includes particles that serve as identification markers.

[0040] Figure 6A 、 6B , 6C, and 6D are photographs of an electro-optical device having an active region that is a coating on a backplane substrate, where the electro-optical device is illuminated by (1) a typical fluorescent lamp, and (2) blue light.

[0041] Figure 7 is a diagram of the interaction of incident light with the electro-optical device. The active area of ​​the electro-optical device is the coating on the adhesive layer side of the backplane substrate. DETAILED DESCRIPTION

[0042] The present invention provides an electro-optical device comprising an active area with identification markings in one of its layers, enabling identification of the manufacturing origin of the device and its components. The technology also enables identification of the manufacturing batch of the electro-optical device and its components at any time during the life of the device.

[0043] The electro-optical device of the present invention includes, in sequence, a conductive light-transmitting layer, an electro-optical material layer, an adhesive layer, and a backplane substrate. The backplane substrate includes a plurality of pixel electrodes configured to apply an electric potential between the conductive light-transmitting layer and the pixel electrodes. The electro-optical device includes an activation region having an identification mark that emits radiation having a characteristic wavelength profile when activated by a stimulus, wherein the activation region is located in one layer of the electro-optical device.

[0044] A common method for manufacturing electro-optical devices involves the use of a front plane laminate (FPL), which, in sequence, includes a conductive, light-transmitting layer, a layer of electro-optical material, an adhesive layer, and a release film. The FPL can be produced at one location and stored or shipped to another. It can be used to manufacture the corresponding electro-optical device when and where it is needed. The release film can be simply removed, exposing the adhesive layer and enabling the manufacturer to simply attach a backplane substrate to obtain the electro-optical device. The inclusion of an activation area with an identification mark in one layer of the FPL enables verification of the manufacturing origin of the FPL and identification of the manufacturing batch of the FPL at any time during the service life of the FPL and the resulting electro-optical device.

[0045] Another method for manufacturing an electro-optical device involves the use of a double release sheet comprising, in sequence, a first release film, a first adhesive layer, a layer of electro-optical material, an adhesive layer; and a second release film. The double release film can be produced at one location and stored or shipped to another location. It can be used to manufacture the corresponding electro-optical device when and where it is needed. The first release film can be removed, exposing the first adhesive layer and enabling the manufacturer to attach the conductive light-transmitting layer. The second release film can then be removed, exposing the second adhesive layer and enabling the manufacturer to simply attach a backplane substrate to the second adhesive layer to obtain the electro-optical device. The inclusion of an activation area with an identification mark in one layer of the double release sheet enables verification of the manufacturing source of the double release sheet and identification of the manufacturing batch of the double release sheet at any time during the service life of the double release sheet and the resulting electro-optical device.

[0046] The term "light" as used herein is electromagnetic radiation of any wavelength, not just electromagnetic radiation in the visible spectrum.

[0047] The ideal activation area and corresponding identification markers have the following characteristics: a. It should be easily detectable by visual inspection or by using analytical instruments; b. It should not significantly interfere with the operation or appearance of the electro-optical device.

[0048] The identification mark may be a fluorescent dye, a fluorescent pigment, a phosphorescent dye, a phosphorescent pigment or a mixture thereof.

[0049] The identification mark may include a fluorescent dye or a combination of two or more fluorescent dyes. The identification mark may also include a fluorescent pigment or a combination of fluorescent pigments. The identification mark may also include a combination of a fluorescent dye and a fluorescent pigment. A fluorescent dye or fluorescent pigment is a compound that absorbs light and re-emit it at a different wavelength. Typically, the emission wavelength is longer than the wavelength of the incident light.

[0050] A dye is a material that is soluble in the medium of the composition in which it is used. In contrast, a pigment is a material that is insoluble in the medium of the composition in which it is used, and it exists in a solid form.

[0051] The identification mark may comprise a phosphorescent dye or a combination of two or more phosphorescent dyes. The identification mark may also comprise a phosphorescent pigment or a combination of phosphorescent pigments. The identification mark may also comprise a combination of a phosphorescent dye and a phosphorescent pigment. A phosphorescent dye or phosphorescent pigment is a compound that absorbs light and re-emit light at a different wavelength, wherein the emission occurs over a period of time after exposure to light that is generally longer than in the case of fluorescence.

[0052] Fluorescent and phosphorescent dyes and pigments, which may be collectively referred to as luminescent dyes and pigments, may be members of the chemical classes of acridine, cyanine, fluorone, luciferin, oxazine, phenanthridine, and rhodamine. Non-limiting examples of luminescent dyes and pigments are acridine orange, acridine yellow, acridinium, GelGreen, Cy2, Cy3, Cy3.5, Cy5, Cy5.5, Cy7, Cy7.5, DiI, DiOC6, heptamethine dye, indocyanine green, merocyanine, SYBR Green I, SYBR Safe, Sytox, YOYO-1, calcein, carboxyfluorescein diacetate N-succinimidyl ester, carboxyfluorescein N-succinimidyl ester, dichlorofluorescein, 6-carboxyfluorescein, Eosin Y, Eosin B, erythrosine, fluo-3, fluo-4, fluorescein, amide fluorescein, fluorescein 1, SYBR Green 1, SYBR Safe, Sytox, YOYO-1, calcein, carboxyfluorescein diacetate N-succinimidyl ester, carboxyfluorescein N-succinimidyl ester, dichlorofluorescein, 6-carboxyfluorescein, Eosin Y, Eosin B, erythrosine, fluo-3, fluo-4, fluorescein, fluorescein 1, fluorescein 2, fluorescein 3, fluorescein 4, fluorescein 5, fluorescein 6, fluorescein 7, fluorescein 8, fluorescein 9, fluorescein 10, fluorescein 11, fluorescein 12, fluorescein The following substances are listed in the table: fluorescein isothiocyanate, fluorescein isothiocyanate, Indian yellow, mercurochrome, Pacific blue, fluorescein B, seminaphtharhodafluor, coelenterazine, firefly fluorescein, fluorescein fluorescein, brilliant cresyl blue, cresyl violet, gallocyanine, Nile blue, Nile red, resazurin, ethidium bromide, gel red, propidium iodide, rhodamine 6G, rhodamine B, rhodamine 123, sulforhodamine 101, Texas Red, and sulforhodamine B.

[0053] The activation zone can be positioned in the adhesive layer or the FPL of electro-optical device, or it can be positioned at the position of adjacent adhesive layer.Under the situation of double release sheet, the activation zone can be positioned in any adhesive layer or it can be positioned at the position of adjacent one or two adhesive layers.For example, the identification mark of the activation zone can be a part for the coating contacted with the adhesive layer.The activation zone can form an image, which comprises letter, numeral or its combination.

[0054] In a variation of the invention, the active area is in the adhesive layer. More specifically, the identification mark may be combined with the adhesive material before the adhesive material is applied to the layer of electro-optical material to create the adhesive layer. Figure 1A and 1BIllustrations of FPLs and electro-optical devices with identifying markings in the adhesive layer are provided. Figure 1A and 1B Examples of different steps in the process of making an FPL and an electro-optical device having identification markings in an adhesive layer are also provided. More specifically, Figure 1A is an example of a process for manufacturing an FPL. An identification mark is mixed with an adhesive material to produce a combination of the adhesive material and the identification mark. This combination is represented by 103. The adhesive material and identification mark combination 103 is then coated on a film 105 to form an adhesive film 105A. The adhesive film is then applied to an article of manufacture, which includes a conductive light-transmitting layer 101 and an electro-optical material layer 102. Thus, an adhesive layer 104A is formed on the electro-optical material layer 102, which contacts the film 105 serving as a release layer. The resulting FPL 106A includes an identification mark that enables verification of the manufacturing origin of the FPL and the resulting electro-optical device, as well as identification of its manufacturing batch.

[0055] A front plane laminate (FPL) is an article that can be used immediately to make an electro-optical device, or it can be stored, shipped, and used later to make an electro-optical device, such as Figure 1B More specifically, the release film can be removed from the FPL 106A and the FPL can be attached to the surface of the backplane substrate 107 to complete the manufacturing process of the electro-optical device 108A. The backplane substrate includes a plurality of pixel electrodes and a driving tool arranged to apply a variable potential to the pixel electrodes.

[0056] The resulting electro-optical device 108A includes identifying markings that enable verification of the electro-optical device's manufacturing origin and identification of its manufacturing batch.

[0057] In another variation of the invention, the activation area of ​​the dual release sheet is located in the adhesive layer of the dual release sheet (and the resulting electro-optical device). Figures 2A to 2E An example of a process for manufacturing an electro-optical device according to the present invention is provided. Figure 2E An example of a dual release sheet comprising an activation area in the adhesive layer is shown in FIG. Figure 2C It is represented as 260 in Chinese. Figure 2A 、 2B 2C provide examples of steps in a process for making a dual release sheet according to the present invention. The identification mark may be combined with an adhesive material before being applied to the first release film 221. The combination of the adhesive material and the identification mark forms a first adhesive composition 222. The first adhesive composition 252 is applied to the first release film 221, forming a first adhesive layer 223 on the first release film 221. Subsequently, a third release film 224 is placed on the first adhesive layer 223 to form a first release roll 220. Figure 2BIn a separate step shown, the electro-optic material composition is coated on a fourth release film 231 to form a structure 230. After peeling the third release film 224 from the first release roller 220 and contacting the exposed first adhesive layer 223 with the electro-optic material layer 232 of the structure 230, an intermediate electro-optic web 240 is formed. The intermediate electro-optic web 240 can be used to form a double release sheet 260, as shown. Figure 2C As shown. A second adhesive composition 252 is applied to a second release film 251 to form a second adhesive layer 253, which is part of a second release roller 250. The second adhesive composition 252 can be made by mixing an identification mark with the adhesive material. After the fourth release film 231 is peeled off from the intermediate electro-optical sheet 240 and the exposed surface of the electro-optical material layer 232 is brought into contact with the second adhesive layer 253 of the second release roller 250, a double release sheet 260 is formed. The identification mark can be included in one of the adhesive layers 223 or 253. The identification mark can be included in both the first adhesive layer 223 and the second adhesive layer 253. In the latter case, the first adhesive layer 223 can include an identification mark or a combination of different identification marks than the identification mark (or combination of identification marks) included in the second adhesive layer 253 of the double release sheet.

[0058] Dual release sheets 260 containing one or more identifying indicia in one or both of their adhesive layers can be stored and used later in the production of electro-optical devices. Figure 2D and 2E An example of the steps of a process for manufacturing an electro-optical device using a double release sheet is shown. Second release film 251 of double release sheet 260 is removed, and backplane substrate 270 is attached to the exposed surface of second adhesive layer 253 to form structure 275. First release film 221 is then removed from structure 275, and exposed first adhesive layer 223 is attached to light-transmitting conductive electrode 280 to form electro-optical device 290 including light-transmitting conductive electrode layer 281. Attaching light-transmitting conductive electrode 280 to the double release sheet can be performed before attaching backplane substrate 270. The resulting electro-optical device 290 includes at least one identifying mark (or combination of identifying marks) in at least one of its adhesive layers, just like the double release sheet form from which it is made. The identifying mark or combination of identifying marks enables verification of the manufacturing origin of the electro-optical device and identification of the batch of electro-optical devices manufactured.

[0059] Verification of the manufacturing origin and / or identification of the manufacturing batch of an electro-optical device can be performed by illuminating the surface of the backplane substrate with light (stimulus), causing an identification mark to emit radiation with a characteristic wavelength profile that is visible or measurable from the outer surface of the backplane substrate. Thus, visual inspection or spectroscopic measurement of the radiation with the characteristic wavelength profile emitted from the backplane substrate can determine the authenticity (or inauthenticity) of the electro-optical device. Despite the presence of pixel electrodes therein, the backplane substrate is typically (or can be designed to be) at least partially transmissive to ultraviolet, visible, and near-infrared radiation, making this process feasible. Even in cases where the backplane substrate is opaque (with respect to the aforementioned regions of the electromagnetic spectrum), verification of the manufacturing origin and / or identification of the manufacturing batch of the electro-optical device can be achieved by separating the backplane substrate from the rest of the device, verifying the manufacturing origin and / or identifying the manufacturing batch of the device when necessary, and reattaching the backplane substrate to the rest of the device. Alternatively, verification and / or identification can be achieved through the use of an identification mark that does not rely on ultraviolet, visible, or near-infrared radiation. Identification markers that provide a characteristic response to higher energy radiation, such as x-rays or gamma rays, may be used.

[0060] In a variation of the present invention, the active area is adjacent to the adhesive layer. More specifically, the active area can be a coating on a layer of the electro-optical device that contacts the adhesive layer. The active area can be (a) a coating on the electro-optical material layer, (b) a coating on the film forming the release layer (created before the adhesive composition is applied to the film), or (c) a coating on the backplane substrate. In the case of an FPL, the active area can be (a) a coating on the electro-optical material layer, (b) a coating on the adhesive layer, created before the first release film is attached, or (c) a coating on the release film. In the case of a dual release sheet, the active area can be (a) a coating on the backplane substrate, (b) a coating on the first adhesive layer, created before the first release film is attached, (c) a coating on the first release film, (d) a coating on the second adhesive layer, created before the second release film is attached, (e) a coating on the first release film, or (f) a coating on the second release film.

[0061] The identification mark itself or a solution of the identification mark or a dispersion of the identification mark may be used in the coating.The coating may also comprise a film-forming polymer. Figure 3A and 3B Provides illustrations of FPLs and electro-optical devices using FPLs. The active area is a coating on the backplane substrate. Figure 3AThis is an example of a process for manufacturing an FPL. Adhesive material 109 is applied to film 105 to create adhesive film 105B. The adhesive film is then applied to electro-optical material layer 102. The electro-optical material layer is in contact with conductive light-transmitting layer 101. This process forms FPL 106B. This is an article that can be used immediately to manufacture electro-optical devices, or it can be stored, shipped, and later used to manufacture electro-optical devices, such as Figure 3B As shown. More specifically, the release film can be removed from the FPL 106B and the FPL can be attached to the backplane substrate 107 to complete the manufacturing process of the electro-optical device 108B. In this example, the backplane substrate has been pre-coated with a composition 103 containing an identification mark. The activation area, i.e., the coating 110, can be performed using any coating technology, such as pre-metered coating such as patch die coating, slot or extrusion coating, slide or stack coating, curtain coating; roll coating such as roller blade coating, forward and reverse roll coating; embossing; gravure coating; flexographic printing; dip coating; spray coating; meniscus coating; spin coating; brush coating; air knife coating; screen printing process; electrostatic printing process; thermal printing process; inkjet printing process; and other similar techniques.

[0062] Figure 3C An illustration of electro-optical device 108B is provided as viewed from the top surface of the electro-optical device from the side where the conductive light transmissive layer is located. Active areas 110 are on the backplane substrate and in contact with adhesive layer 104. The active areas form an image including letters ("EPD").

[0063] There are various scenarios for how this method can be used to verify the manufacturing origin and identify manufacturing batches of FPLs, double release sheets, and electro-optical devices. As described above, an identification marker (e.g., a fluorescent dye or pigment) that emits a characteristic wavelength profile (when activated by a stimulus) can be mixed into the adhesive material before forming the adhesive layer of the FPL or double release sheet. The emission can be observed visually or measured spectroscopically. Multiple fluorescent and / or phosphorescent dyes can be used in varying proportions to make the emission profile more complex and to encode additional information that can be detected during the service life of the FPL, double release sheet, or electro-optical device. In other words, the wavelength peak and the light amplitude at the peak, depending on the properties of the dyes and the quantitative ratio of the dyes, can encode a variety of information, such as the manufacturing location, manufacturing time, manufacturing batch, material source, etc.

[0064] Identification marks can also be applied to one or more of the multiple surface layers of an FPL, double release sheet, or electro-optical device. As described above, coatings provide additional flexibility by allowing the creation of multiple images that can be detected upon activation. These images can include numbers and letters corresponding to the manufacturing batch and other specific information of the FPL, double release sheet, or electro-optical device. In the case of an FPL and corresponding electro-optical device, the activation area can be the result of (a) a coating on the electro-optical material layer before attaching the adhesive layer, (b) a coating on the surface of the film forming the release layer before applying the adhesive composition to the film, or (c) a coating on the backplane substrate before attaching the FPL's adhesive layer. In option (b), the activation area at least partially remains on the surface of the adhesive layer after removing the release film. Furthermore, multiple identification marks, such as fluorescent dyes, can be incorporated into the same FPL and electro-optical device at different locations, further complicating the emitted light and encoding more information about the electro-optical device, FPL, and its components. In the case of a dual release sheet and corresponding electro-optical device, the active area can be (a) a coating on the backplane substrate, (b) a coating on the first adhesive layer, which is created before the first release film is attached, (c) a coating on the first release film, (d) a coating on the second adhesive layer, which is created before the second release film is attached, (e) a coating on the first release film, or (f) a coating on the second release film.

[0065] A variety of stimuli can be used to activate the identification marker, such as (a) electromagnetic radiation in the visible and near infrared regions of the electromagnetic spectrum having a wavelength of about 400 nm to about 1000 nm, (b) electromagnetic radiation in the ultraviolet region of the electromagnetic spectrum having a wavelength of about 200 nm to about 400 nm, (c) electromagnetic radiation in the x-ray region of the electromagnetic spectrum having a wavelength of about 0.01 nm to about 10 nm, and (d) electromagnetic radiation in the gamma ray region of the electromagnetic spectrum having a wavelength of about 10 -2 to about 10 -6Electromagnetic radiation with a wavelength of 100 nm or more must be emitted from the FPL, double-release sheet, or electro-optical device and reach the identification tag to elicit a response in the form of a characteristic emission. The radiation emitted from the identification tag must also pass through the FPL, double-release sheet, or electro-optical device to be detectable from outside the FPL, double-release sheet, or electro-optical device. In this case, the layers of the FPL, double-release sheet, or electro-optical device must at least partially transmit near-infrared, visible, or ultraviolet radiation. Using an identification tag that is activatable by electromagnetic radiation and emits a characteristic wavelength profile with longer wavelengths (lower energy) allows verification of the manufacturing origin and identification of batches of FPLs, double-release sheets, and devices that are opaque to near-infrared, visible, or ultraviolet radiation. Lanthanides of the periodic table, such as europium, gadolinium, and terbium, and their salts, can be used as identification tags. They can be activated by x-rays and gamma rays. X-rays and gamma rays readily penetrate the materials used in electro-optical devices. The penetration of this high-energy electromagnetic radiation is only blocked by thick layers of heavy metals (such as lead). Upon activation with x-rays and gamma rays, lanthanide metals and their salts emit characteristic spectra that can be detected via x-ray fluorescence (XRF). XRF has very low detection limits (in the ppm range), meaning that very small amounts of lanthanide metals or their salts are sufficient to verify an FPL, dual-release sheet, or electro-optical device. The lanthanide metal or its salt can be present in any layer of the FPL, dual-release sheet, or electro-optical device, such as the adhesive layer or electro-optical material layer, or it can be part of a coating on any layer. In addition to the aforementioned elements (europium, gadolinium, and terbium), the lanthanide series includes lanthanum, cerium, praseodymium, neodymium, promethium, samarium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.

[0066] In another variant of the invention, the identification mark may be present in the FPL, double release sheet and electro-optical device in the form of particles located in the layer of electro-optical material. These particles may be charged or uncharged.

[0067] As described above, in certain types of electro-optical devices (or FPLs, or dual-release sheets), the electro-optical material layer includes an electrophoretic medium having a plurality of first charged particles that migrate through a fluid under the influence of an electric field, resulting in different display states differing in at least one optical property. The electrophoretic medium may be encapsulated by a plurality of microcapsules having microcapsule shells. Typically, such electro-optical devices include a plurality of at least one charged particle, but they may include a variety of particles contributing to a variety of potential optical states. The encapsulated electrophoretic medium may also include a plurality of second charged or uncharged particles, where the second particles may be identifying markers. Visual inspection, microscopic examination, or spectroscopic analysis of the electro-optical device (or FPL, or dual-release sheet) allows the second particles to be distinguished from the first particles and any other particles present in the electrophoretic medium. Instead of being in microcapsule form, the electrophoretic medium may be present in a plurality of microcells formed using a polymer material, as described above.

[0068] The electro-optical material of the electro-optical device (or FPL, or dual-release sheet) may include an electrophoretic medium comprising a plurality of first and second charged particles that migrate through a fluid under the influence of an electric field, resulting in different display states that differ in at least one optical property. The electrophoretic medium may be encapsulated by a plurality of microcapsules having a microcapsule shell. The encapsulated electrophoretic medium may further include a plurality of third pigment particles as part of the microcapsule shell, and the third particles may be an identifying marker. The third particles can be distinguished from the first particles, the second charged particles, and any other particles in the electrophoretic medium by visual inspection, microscopic examination, or spectroscopic analysis of the electro-optical device (or FPL, or dual-release sheet).

[0069] A typical method for making encapsulated electrophoretic media includes the following steps: (a) mixing an aqueous mixture of gelatin and gum arabic polymer in a hydrocarbon solvent in the presence of emulsion droplets containing charged particles; (b) heating the mixture to about 40°C and lowering the pH to about 4.9 to form microcapsules having a shell comprising a gelatin / gum arabic coacervate; (c) lowering the temperature of the mixture to about 10°C; (e) adding an aqueous solution of glutaraldehyde to crosslink the microcapsule shell; (f) vigorously mixing the mixture at about 25°C for more than 12 hours; (g) raising the temperature to 50°C and mixing for an additional hour to remove excess crosslinking agent; and (g) separating capsules larger than 100 μm by sieving. The retained microcapsules are mixed with a polymer binder and coated on an electro-optical electrode to form an electro-optical material layer.

[0070] As described above, including a small amount of an additional species of charged particles in the total content of charged particles in the electrophoretic medium can enable verification of the corresponding electro-optical device. In other words, the additional species of charged particles can serve as identification markers in the corresponding FPL, double-release sheet, and electro-optical device. To effectively serve as identification markers, the species of the charged particles must be detectable through visual inspection of the electro-optical device (or FPL, or double-release sheet) or through measurement using an analytical instrument (such as an optical microscope). Spectroscopic measurement using various techniques (such as UV-Vis spectroscopy, infrared spectroscopy, X-ray fluorescence, etc.) can also be used. Therefore, the charged particle identification marker preferably has at least one different property from the other species of charged particles in the electro-optical material layer. It can have a different color, shape, or size than the other species of charged particles. Alternatively, the charged particle identification marker can be a fluorescent or phosphorescent pigment, which can be detected by emitting electromagnetic radiation with a characteristic wavelength profile when excited by electromagnetic radiation of a specific wavelength. In order to avoid that the identification mark significantly interferes with the operation of the electro-optical device and its optical state, preferably, the content of the charged particle identification mark is relatively low compared to the total weight content of the charged particles present in the electro-optical material layer. Therefore, the charged particle identification mark can be about 0.01 weight % to about 2 weight % of the weight of the total charged particle content of the electro-optical material layer, more preferably, about 0.02 weight % to about 0.5 weight %, even more preferably, about 0.05 weight % to about 0.2 weight %. Certain protocols for applying an electric field can be used to verify the device based on the charged particle identification mark. For typical visual inspection or optical microscopy, the charged particles must be visible from the surface of the electro-optical material layer.

[0071] Figure 4 An illustration of an example is provided in which the identification mark is a positively charged particle 116 in an encapsulated electrophoretic medium 114. In this example, the electro-optic medium of the electro-optic layer 102 also includes positively charged black pigment particles 115A and negatively charged white particles 114B. An electric field is applied across the electrodes of the device, with a negative charge on the conductive, light-transmitting electrode 101, causing the positively charged particles 115A and 116 to move closer to the viewing side of the electro-optic device and the negatively charged white particles to move toward the opposite side of the electro-optic layer. This enables visual inspection or spectroscopic determination of the charged particle identification mark to verify the electro-optic material layer and the corresponding electro-optic device. It will be understood by those skilled in the art that the identification mark can also be a negatively charged particle.

[0072] The inclusion of a small content of an additional type of uncharged particles in the total content of charged particles in the electrophoretic medium can also make it possible to verify the corresponding electro-optical device (FPL and double release sheet). It has been observed that even if the particles do not contain an electric charge, the particles can be driven to a position near the observation side of the electrophoretic medium. More specifically, if a high voltage electric field is applied across the electro-optical material layer, the flow of the moving charged particles toward the observation side of the electrophoretic medium will generate an air flow, and even bring the uncharged particles to a position near the observation side of the electrophoretic medium. As described above for the case of the charged particle identification mark, in order to effectively serve as an identification mark, it is preferred that the uncharged particle identification mark has at least one different property compared to other types of charged particles in the electro-optical material layer. The uncharged particle identification mark can also be a fluorescent or phosphorescent pigment. It is also preferred that the content of the charged particle identification mark is relatively low compared to the total weight content of the charged particles present in the electro-optical material layer. Therefore, the charged particle identification mark can be about 0.01 wt% to about 2 wt% of the total charged particle content of the electro-optical material layer, more preferably, about 0.02 wt% to about 0.5 wt%, and even more preferably, about 0.05 wt% to about 0.2 wt%.

[0073] In another variation of the present invention, in which the electro-optical device includes an encapsulated electrophoretic medium, the identification marker of the present invention can be pigment particles that are part of the microcapsule shell of the encapsulated electrophoretic medium. These particles can be charged or uncharged. It has been observed that in the case of the encapsulation process described above, in which the polar pigment particles are present in an emulsion, some or all of the polar pigment particles become part of the shell of the electrophoretic medium rather than being present within the microcapsules. Visual, microscopic, or spectroscopic analysis of the encapsulated electrophoretic medium can then verify the electro-optical material layer and the corresponding electro-optical device (or FPL). Preferably, the content of the polar particle identification marker is relatively low compared to the total weight content of charged particles present in the electro-optical material layer. Thus, the charged particle identification marker can be from about 0.01 wt% to about 0.5 wt%, more preferably, from about 0.02 wt% to about 0.3 wt%, and even more preferably, from about 0.05 wt% to about 0.1 wt% of the total charged particle content of the electro-optical material layer.

[0074] Figure 5 An illustration of an example is provided in which an identifying mark (polar pigment particles 119) is present in the shell of an encapsulated electrophoretic medium 114. In this example, the electro-optic medium of the electro-optic layer 102 also includes black pigment particles 115A and white particles 114B. Visual, microscopic, or spectroscopic testing of the shell of the microcapsule for the presence of the polar pigment particles can then verify the electro-optic material layer and the corresponding electro-optic device.

[0075] More than one activation zone can be used in different areas of an electro-optical device or an FPL or a double release sheet. This can make it possible to verify the different components or materials contained in the components of the electro-optical device or an FPL or a double release sheet. The complexity of the stimulus or radiation emission applied can also be increased to make the verification protocol more complicated, thereby enabling the additional information that can be detected during the useful life of the FPL, a double release sheet or an electro-optical device to be encoded. In addition, using a combination of two or more identification marks can make it possible to encode and retrieve more information about the electro-optical device or an FPL or a double release sheet.

[0076] Example An example of this method was evaluated as described below.

[0077] An aqueous dye solution containing 5 wt% of the fluorescent dye Lucifer Yellow (supplied by Sigma-Aldrich) based on the weight of the aqueous dye solution was mixed with an equal amount of an aqueous polymer solution containing 5 wt% of poly(vinyl alcohol) based on the weight of the aqueous polymer solution. The combined solution was coated onto a backplane substrate. The coating was performed so that the word "E Ink" was formed as a latent image on the backplane substrate. Lucifer Yellow is a fluorescent dye that is activated by ultraviolet light or blue visible light. When activated, this dye emits in the visible light region of the electromagnetic spectrum and emits at a maximum absorption wavelength that is longer than that of blue visible light. The FPL, which sequentially includes a conductive light-transmitting layer, an electro-optical material, an adhesive layer, and a release film, is attached to the backplane substrate after removing the release film. The attachment is performed so that the coating of the fluorescent dye is in contact with the adhesive layer of the FPL. A fluorescent lamp (60 W, 1050 lumens) was used to illuminate the conductive light-transmitting layer and the backplane substrate of the electro-optical device. Photographs of the front of the device (conductive light-transmitting layer) and the back of the device (backplane substrate) were obtained. The images are respectively at Figure 6A and 6C Then, the conductive light-transmitting layer and the backplane substrate of the electro-optical device were irradiated with blue light. Photos of the front of the device (conductive light-transmitting layer) and the back of the device (backplane substrate) were obtained. The images are respectively Figure 6B and 6D Available in.

[0078] The electro-optic material layer of the FPL used in this example is opaque. It is therefore not surprising that no emission of the fluorescent dye was observed from the surface of the electro-optical device where the conductive light-transmitting electrodes were located, regardless of the nature of the incident light. In the case of attempts to activate the fluorescent dye using ordinary fluorescent bulbs, no emission was observed from any surface of the electro-optical device. The incident light that can enter the device from the partially light-transmitting backplane substrate does not have a high enough frequency, that is, it does not have a short enough wavelength to activate the fluorescent dye. However, irradiating the backplane substrate with blue light activates the fluorescent dye, which emits light in the visible region and at a maximum absorption wavelength that is longer than the wavelength of the blue incident light. As Figure 6D As shown in the photo of the backplane substrate, this emission is clearly visible to an observer when looking at the outer surface of the backplane substrate. The word "E Ink" can be clearly seen in the photo.

[0079] Figure 7 A simplified illustration of the concept of light absorption and emission of a fluorescent dye present in an activated area is provided. In this case, a coating 109 on a backplane substrate 107 in contact with an adhesive layer 104 includes a fluorescent dye. Incident blue light 111 activates the fluorescent dye and emits longer wavelength light 113 visible to an observer. Conversely, when incident blue light 111 does not encounter a fluorescent dye in its path, it is reflected back as light 112 of the same wavelength as the incident blue light. This demonstrates how a coating can represent an image, such as text ("E Ink"), and how activation with blue light can form Figure 6D photos.

[0080] This example shows how fluorescent dyes can be used to authenticate electro-optical devices.

[0081] The electro-optical device (or FPL, or dual-release sheet) of the present invention may also include an identifying mark, or a combination of identifying marks, including filaments, fibers, and / or other microparticles with a unique, easily detectable structure. One example of such an identifying mark is a taggant. Taggetants are used in explosives, but are also used in commodity materials and even documents. Preferably, these filaments, fibers, and microparticles are invisible to the naked eye, but are observable and their characteristics can be detected microscopically or have a unique spectral signature. Invisibility is particularly important if the location of the identifying mark affects the optical performance of the device, for example, if it affects the transparency of a transparent layer. Fibers and / or microparticles can be encoded by a selected combination and concentration of marking elements. Marking elements can include color / color combination, particle shape, metal content, distinct domains resulting from a combination of polymers, the presence of a magnetic component, and so on. One example of such a taggant is a polymer microparticle material, where each polymer microparticle includes distinct segments with different colors. These particles can be detected microscopically or even with a magnifying glass. Another example of a taggant is a fiber material comprising multiple fiber components, such as different polymers and other components, melting characteristics, and so on. The examples above demonstrate that such multi-component fibers and particles with unique patterns can encode simple or complex information for identification purposes. The filaments, fibers, and microparticles representing the code can be incorporated into one or more layers of, or adjacent to, an electro-optical device (or frontal laminate or dual release sheet). This type of identification marking can be used to identify or authenticate the device even after it has been exposed to mechanical or other destructive factors, such as fire or explosion, because the filaments, fibers, and microparticles can be collected from the surrounding area and analyzed.

[0082] Although preferred embodiments of the present invention have been shown and described herein, it should be understood that such embodiments are provided only as examples. Without departing from the spirit of the present invention, those skilled in the art will appreciate many variations, changes, and replacements. Therefore, the appended claims are intended to encompass all such variations that fall within the spirit and scope of the present invention. If there is any inconsistency between the content of the present application and any patent and application incorporated herein by reference, the content of the present application should be controlled within the required scope for resolving such inconsistencies.

Claims

1. An electro-optical device comprising: a. Conductive light-transmitting layer; b. electro-optical material layer; c. adhesive layer; as well as d. a backplane substrate comprising a plurality of pixel electrodes, wherein the plurality of pixel electrodes are configured to apply an electric potential between the conductive light-transmitting layer and the pixel electrodes; The electro-optical device includes an activation region having an identification mark that emits radiation of a characteristic wavelength profile when activated by a stimulus, wherein the activation region is located in the adhesive layer, and wherein the adhesive layer is a combination of an adhesive material and the identification mark. The electro-optical device of claim 1 , wherein the adhesive layer comprises a polyurethane polymer.

3. The electro-optical device of claim 1, wherein the identification mark comprises a fluorescent dye, a fluorescent pigment, a phosphorescent dye, a phosphorescent pigment, or a mixture thereof.

4. The electro-optical device of claim 2, wherein the identification mark comprises two or more fluorescent dyes or pigments.

5. The electro-optical device of claim 3, wherein the fluorescent dye, the fluorescent pigment, the phosphorescent dye, or the phosphorescent pigment is a member of the acridine, cyanine, fluoroone, luciferin, oxazine, phenanthridine, or rhodamine chemical class. The electro-optical device according to claim 1 , wherein the identification mark is a metal or a metal salt of a lanthanide element.

7. The electro-optical device according to claim 6, wherein the identification mark is a metal of the lanthanide series, the metal being europium, gadolinium or terbium.

8. The electro-optical device of claim 6, wherein the identification mark is a metal salt of europium, gadolinium, or terbium.

9. The electro-optical device of claim 1, wherein the stimulus comprises light having an average wavelength of about 400 nm to about 1000 nm.

10. The electro-optical device of claim 1, wherein the stimulus comprises light having an average wavelength of about 200 nm to about 400 nm.

11. The electro-optical device of claim 1, wherein the stimulus comprises light having an average wavelength of about 0.01 nm to about 10 nm. 12 . The electro-optic device according to claim 1 , wherein the electro-optic material layer comprises an electrophoretic medium comprising a plurality of first particles dispersed in hydrophobic oil, wherein the first particles are charged.

13. A front plane laminate for use in manufacturing an electro-optical device, comprising: a. Conductive light-transmitting layer; b. electro-optical material layer; c. adhesive layer; as well as d. Release film; The electro-optical device includes an activation region having an identification mark that emits radiation of a characteristic wavelength profile when activated by a stimulus, wherein the activation region is located in the adhesive layer, and wherein the adhesive layer is a combination of an adhesive material and the identification mark.

14. The front plane laminate of claim 13, wherein the identification mark comprises a fluorescent dye, a fluorescent pigment, a phosphorescent dye, a phosphorescent pigment, or a mixture thereof.

15. The front plane laminate of claim 13, wherein the identification mark is a metal or metal salt of a lanthanide element.

16. A double release sheet for manufacturing an electro-optical device, comprising: a. a first release film; b. a first adhesive layer; c. electro-optical material layer; d. adhesive layer; as well as e. a second release film; The electro-optical device includes an activation area having an identification mark, which emits radiation with a characteristic wavelength profile when stimulated and activated, wherein the activation area is located in the first adhesive layer or the second adhesive layer, and wherein the first adhesive layer or the second adhesive layer is a combination of an adhesive material and the identification mark.

17. The dual release sheet according to claim 16, wherein the identification mark comprises a fluorescent dye, a fluorescent pigment, a phosphorescent dye, a phosphorescent pigment, or a mixture thereof.

18. The dual release tablet according to claim 16, wherein the identification mark is a metal or a metal salt of a lanthanide element.

19. A method of verifying an electro-optical device and any component thereof, comprising the steps of: providing an electro-optical device comprising, in order, a conductive light-transmitting layer, a layer of electro-optical material, an adhesive layer, and a backplane substrate comprising a plurality of pixel electrodes, the plurality of pixel electrodes being configured to apply an electric potential between the conductive light-transmitting layer and the pixel electrodes, wherein the adhesive layer comprises a mixture of an adhesive material and an identification mark, wherein the identification mark emits radiation of a characteristic wavelength profile when activated; activating the identification marker by stimulation; detecting emitted electromagnetic radiation caused by the identification mark; as well as Determining the authenticity of the electro-optical device or any component thereof or determining the manufacturing batch of the electro-optical device or any component thereof.

20. The method of authenticating an electro-optical device and any component thereof according to claim 19, wherein the identification mark comprises a fluorescent dye, a fluorescent pigment, a phosphorescent dye, a phosphorescent pigment or a mixture thereof.

Images