FRONT PLANE LAMINATE WITH ELECTRICAL CONNECTIONS ON OUTER SURFACES - Patent application

Abstract

A light-transmitting substrate having an inner surface, an outer surface opposite the inner surface, and a plurality of through-holes. When combined with a light-transmitting conductive material such as indium tin oxide (ITO), the substrate provides electrical connection between a light-transmitting conductive layer that can be used as a top electrode in an electro-optic display and contact spots on the outer surface of the light-transmitting substrate. Thus, the light-transmitting substrate allows for simpler electrical connections for electro-optic displays, particularly for large-format devices that may need to be cut or assembled in the field. Additionally, the redundancy of tens to hundreds of electrical contacts minimizes the possibility of a broken electrical connection rendering the device inoperable.

Description

[Technical field]

[0001] (Related Applications) This application claims priority to U.S. Provisional Patent Application No. 63 / 086,695, filed October 2, 2020. All patents and publications disclosed herein are incorporated by reference in their entirety.

[0002] FIELD OF THEINVENTION The present invention relates to front plane laminates, methods of making the laminates, and electro-optic displays formed from the laminates. More specifically, in one aspect, the present invention relates to a front plane laminate having a substrate including interspersed portions distributed within a continuous portion. The interspersed portions include a conductive material that forms an electrical connection between a conductive layer of the front plane laminate and contact spots on an outer surface of the substrate. [Background technology]

[0003] (background) An electro-optical display comprises a layer of electro-optical material. The term "electro-optical", as applied to a material or display, is used herein in its conventional sense in the imaging arts to refer to a material having first and second display states differing in at least one optical property, the material being changed from its first display state to its second display state by application of an electric field to the material. The optical property is typically a color perceptible to the human eye, but it may also be optical transmittance, reflectance, luminescence, or, in the case of displays intended for machine reading, another optical property such as pseudocolor in the sense of a change in reflection of electromagnetic wavelengths outside the visible range.

[0004] Several types of electro-optic displays are known. One type of electro-optic display is the rotating dichroic member type, as described, for example, in U.S. Pat. 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 dichroic ball" display, but in some of the above-mentioned patents the rotating member is not spherical, so the term "rotating dichroic member" is preferred as it is more accurate). Such displays use a large number of small bodies (typically spherical or cylindrical) that have two or more portions with different optical properties and an internal dipole. These objects are suspended within liquid-filled vacuoles in a matrix, and the vacuoles are filled with liquid so that the objects are free to rotate. The appearance of the display is altered by applying an electric field to it, thereby rotating the objects into various positions and changing the portion of the objects that is seen through the viewing surface.

[0005] Another type of electro-optic display uses an electrochromic medium, e.g., in the form of a nanochromic film comprising electrodes formed at least in part from a semiconducting metal oxide and a plurality of dye molecules attached to the electrodes capable of reversible color change. See, e.g., 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. Pat. Nos. 6,301,038, 6,870,657, and 6,950,220. This type of medium is also typically bistable.

[0006] Another type of electro-optic display is the electrowetting display developed by Philips and described in Hayes, RA, et al, "Video-Speed ​​Electronic Paper Based on Electrowetting", Nature, 425, 383-385 (2003). In U.S. Patent No. 7,420,549, it is shown that such electrowetting displays can be made bistable. Other well-known electro-optic display materials include liquid crystal displays (LCDs), organic light-emitting diode displays (OLEDs), light-emitting diodes (LEDs), and micro / mini LEDs.

[0007] One type of electro-optic display that has been the subject of intense research and development for many years is the particle-based electrophoretic display, in which multiple charged particles move through a fluid under the influence of an electric field. Electrophoretic displays can have attributes of good brightness and contrast, wide viewing angles, state bistability, and low power consumption compared to liquid crystal displays.

[0008] Numerous patents and applications assigned to or in the name of Massachusetts Institute of Technology (MIT), E Ink Corporation, E Ink California, LLC, and related companies describe various techniques used for encapsulation and microcell electrophoresis and other electro-optic media. Encapsulated electrophoretic media comprises a number of small capsules, each of which itself comprises an internal phase containing electrophoretically mobile particles in a fluid medium, and a capsule wall surrounding the internal phase. Typically, the capsules themselves are held in a polymer binder to form a coherent layer positioned between two electrodes. In microcell electrophoretic displays, the charged particles and fluid are not encapsulated in microcapsules, but instead are retained within a number of cavities formed in a carrier medium, typically a polymer film. Techniques described in these patents and applications include: (a) Electrophoretic particles, fluids, and fluid additives (see, e.g., U.S. Pat. Nos. 7,002,728 and 7,679,814) (b) Capsules, binders, and encapsulation processes (see, e.g., U.S. Pat. Nos. 6,922,276 and 7,411,719) (c) Microcell structures, wall materials, and methods of forming the microcells (see, e.g., U.S. Pat. Nos. 7,072,095 and 9,279,906). (d) Methods for filling and sealing microcells (see, e.g., U.S. Pat. Nos. 7,144,942 and 7,715,088). (e) Films and subassemblies containing electro-optic media (see, e.g., U.S. Pat. Nos. 6,982,178 and 7,839,564) (f) Backplanes, adhesive layers and other auxiliary layers, and methods used in displays (see, e.g., U.S. Pat. Nos. 7,116,318 and 7,535,624) (g) Color formation and color control (see, e.g., U.S. Pat. Nos. 7,075,502 and 7,839,564) (h) Methods for driving displays (see, e.g., U.S. Pat. Nos. 7,012,600 and 7,453,445) (i) Display applications (see, e.g., U.S. Pat. Nos. 7,312,784 and 8,009,348) (j) Non-electrophoretic displays, such as those described in U.S. Pat. No. 6,241,921 and U.S. Patent Application Publication No. 2015 / 0277160, as well as non-display applications of encapsulation and microcell technology (see, e.g., U.S. Patent Application Publication Nos. 2015 / 0005720 and 2016 / 0012710).

[0009] Many of the aforementioned patents and applications recognize that the walls surrounding discrete microcapsules in an encapsulated electrophoretic medium may be replaced by a continuous phase, thereby producing so-called "polymer-dispersed electrophoretic displays" comprising a plurality of discrete droplets of an electrophoretic medium electrophoretic fluid and a continuous phase of a polymeric material, and that the discrete droplets of electrophoretic fluid in such polymer-dispersed electrophoretic displays may be considered capsules or microcapsules even though no discrete capsule membrane is associated with each individual droplet. See, for example, the aforementioned U.S. Patent No. 6,866,760. Thus, for purposes of this application, such polymer-dispersed electrophoretic media are considered a subspecies of encapsulated electrophoretic media.

[0010] Encapsulated electrophoretic displays typically do not suffer from the clustering and settling failure modes of conventional electrophoretic devices and offer 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 "printing" is intended to include all forms of printing and coating, including, but not limited to, patch die coating, slot or extrusion coating, slide or cascade coating, pre-metered coating such as curtain coating, roll coating such as knife-over-roll coating, forward and reverse roll coating, gravure coating, dip coating, spray coating, meniscus coating, spin coating, brush coating, air knife coating, silk screen printing processes, electrostatic printing processes, thermal printing processes, inkjet printing processes, electrophoretic deposition (see U.S. Pat. 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 made. Other types of electro-optic media can also be used in embodiments of the present invention.

[0011] An electro-optic display typically comprises a layer of electro-optic medium and at least two other layers disposed on opposite sides of the electro-optic medium, one of these two layers being an electrode layer. In most such displays, both layers are electrode layers, and one or both of the electrode layers are patterned to define the pixels of the display. For example, one electrode layer may be patterned into elongated row electrodes and the other into 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 commonly, one electrode layer has the form of a single continuous electrode and the other electrode layer is patterned into a matrix of pixel electrodes, each of which defines one pixel of the display. In another type of electro-optic display, intended for use with a stylus, print head, or similar movable electrode separate from the display, only one of the layers adjacent to the electro-optic layer comprises an electrode; the layer opposite the electro-optic layer is typically a protective layer intended to prevent the movable electrode from damaging the electro-optic layer.

[0012] The manufacture of three-layer electrophoretic displays typically involves at least one lamination operation. For example, several of the aforementioned MIT and E Ink patents and applications describe processes for manufacturing encapsulated electrophoretic displays in which an encapsulated electrophoretic medium comprising capsules in a binder is coated onto a light-transmissive conductive layer that acts as the top electrode layer of the final display, which in turn is applied to a light-transmissive substrate. The capsule / binder coating is then dried to form a coherent layer of electrophoretic medium firmly adhered to the conductive layer, to provide an article of manufacture hereafter referred to for convenience as a "front plane laminate" or "FPL."

[0013] Separately, a backplane is prepared that contains an array of pixel electrodes and an appropriate arrangement of conductors for connecting the pixel electrodes to a drive network. To form the final display, the FPL is laminated to the backplane using a lamination adhesive (a very similar process can be used to prepare electrophoretic displays that can be used 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 one exemplary form of such a process, the backplane itself is flexible and is prepared by printing the pixel electrodes and conductors onto a plastic film or other flexible substrate. The usual lamination technique for mass production of displays by this process is roll lamination using a lamination adhesive. Similar manufacturing techniques can be used with other types of electro-optic displays. For example, a microcell electrophoretic medium or a rotating bichromal member medium may be laminated to the backplane in substantially the same manner as an encapsulated electrophoretic medium.

[0014] When the front plane laminate is used in a display, it is necessary to make an electrical connection between a voltage source and the light-transmissive conductive layer through which the electro-optic medium is viewed (this light-transmissive conductive layer is sometimes referred to as the "top plane" electrode). In some cases the connection is made directly using wires or conductive traces that are bonded directly to the conductive layer from a power supply or controller. More typically, the voltage is routed along the backplane using fabricated traces that connect to conductive pads, and the necessary electrical connection is achieved by providing at least one "connection area" of the display that is not in contact with the electro-optic medium, where the top conductive layer is accessible.

[0015] The connection areas can be provided in two different ways. First, the formation of the electro-optic medium layer can be controlled to leave non-coated areas ("gutters") where there is no electro-optic medium, and a portion of these non-coated areas can later serve as the connection areas. Alternatively, the entire surface of the laminate is coated with the electro-optic medium, which can later be removed from the connection areas in any convenient manner, for example by cutting, mechanical abrasion, or chemical degradation of the electro-optic layer. A conductive material, for example a conductive filler such as conductive silver paste or adhesive, is then inserted to contact the connection areas and form an electrical connection between the top electrode layer and a top plane connection (TPC) in the backplane to complete the circuit.

[0016] In some cases, following removal of the electro-optic medium from the connection areas, the stack may require cleaning to remove residue from the electro-optic medium; for example, if the electro-optic medium is an encapsulated electrophoretic material, it may be desirable to remove any internal phase that remains after rupture of the capsule during removal of the electrophoretic material from the connection areas. Because the top conductive layer is typically made of a relatively fragile material such as indium tin oxide (ITO), forming the connection areas and inserting the conductive filler is a delicate process, and the solvent used in cleaning its outer perimeter wall should be selected to dissolve the electro-optic layer without damaging the top conductive layer. Furthermore, the amount of conductive filler should be sufficient to complete the electrical circuit, but not so much that it can flow, creep, or shift, or otherwise tend to cause shorts. Importantly, when the FPL is incorporated into an encapsulated display (aka module), the FPL must be cut and the pieces must be cleaned for top plane connection prior to lamination to the backplane. This requires very precise alignment between the cut pieces and the backplane. Keeping all of the parts clean and aligned is difficult, especially for larger displays, or when fabricating prototype or custom displays without the use of an alignment jig, which is impractical for one-off displays and may even be impossible for some unusually shaped displays. If the pieces in the FPL are made after lamination, the cleaning process is likely to damage the top and / or backplane conductive layers.

[0017] For the reasons stated above, conventional processes for forming top plane connections are complex, time consuming, and if not carefully performed can be prone to damaging the top electrode layer and other components of the final assembly. Thus, a need exists for improved mass production techniques associated with the manufacture of top plane connections. [Prior art documents] [Patent documents]

[0018] [Patent Document 1] U.S. Pat. No. 5,808,783 Summary of the Invention [Means for solving the problem]

[0019] (Summary of the invention) These and other aspects of the present invention will be apparent in view of the following description.

[0020] In a first aspect, provided herein is an article of manufacture comprising, in order, a light-transmissive substrate having an inner surface and an outer surface opposite the inner surface, a light-transmissive conductive layer, a layer of electro-optic medium, an adhesive layer, and a release sheet in contact with the adhesive layer, the layer of electro-optic medium being disposed between the light-transmissive conductive layer and the adhesive layer. The light-transmissive substrate comprises a continuous portion and a plurality of openings in the continuous portion, the openings containing conductive material that forms electrical connections between the light-transmissive conductive layer and contact spots on the outer surface of the light-transmissive substrate.

[0021] In a second aspect, a laminated electro-optic display is provided comprising, in order, a front plane light-transmissive substrate having an inner surface and an outer surface opposite the inner surface, a light-transmissive conductive layer, an electro-optic medium layer in electrical contact with the light-transmissive conductive layer, and a backplane including conductors, the front plane light-transmissive substrate comprising a continuous portion and a plurality of openings within the continuous portion, the openings including conductive material that forms electrical connections between the light-transmissive conductive layer and contact spots on the outer surface of the front plane light-transmissive substrate.

[0022] In a third aspect, an optically transparent conductive material is provided, the optically transparent conductive material comprising an optically transparent substrate having a first surface, a second surface opposite the first surface, and a plurality of through holes, a conductive material selected from aluminum oxide, zinc oxide, indium oxide, indium tin oxide, and poly(3,4-ethylenedioxythiophene) contacting the first surface of the substrate and forming an optically transparent conductive surface adjacent the first surface of the optically transparent substrate while also providing electrical connections through the plurality of through holes to contact spots on the second surface of the optically transparent substrate, the through holes having an average diameter of at least 0.1 micrometers to a maximum of 100 micrometers. In one embodiment, the optically transparent substrate is a polymeric material. In one embodiment, the through holes have an average diameter of at least 0.5 micrometers to a maximum of 10 micrometers. In one embodiment, the through holes are selected from the group consisting of circular, linear, and elliptical. In one embodiment, the contact spots are located on a section of the outer surface of the optically transparent substrate, the section having an average density of at least 10 contact spots per square centimeter and up to 1,000 contact spots per square centimeter.

[0023] In a fourth aspect, a method of manufacturing a laminated electro-optic display is provided, the method including: laminating a front plane laminate to a backplane, the front plane laminate comprising, in order, a front plane light-transmissive substrate having an inner surface and an outer surface opposite the inner surface, a light-transmissive conductive layer, a layer of electro-optic medium in electrical contact with the light-transmissive conductive layer, and an adhesive layer, the front plane light-transmissive substrate comprising a continuous portion and a plurality of openings in the continuous portion, the openings including a conductive material that forms an electrical connection between the light-transmissive conductive layer and contact spots on the outer surface of the front plane light-transmissive substrate, the backplane comprising a top plane connection; and forming an electrical connection between at least one of the contact spots on the outer surface of the front plane light-transmissive substrate and the top plane connection.

[0024] In a fifth aspect, a method of manufacturing a laminated electro-optic display is provided, the method including: laminating a front plane laminate to a backplane, the front plane laminate comprising, in order, a front plane light-transmissive substrate having an inner surface and an outer surface opposite the inner surface, a light-transmissive conductive layer, a layer of electro-optic medium in electrical contact with the light-transmissive conductive layer, and an adhesive layer, the front plane light-transmissive substrate comprising a continuous portion and a plurality of openings in the continuous portion, the openings including a conductive material that forms electrical connections between the light-transmissive conductive layer and contact spots on the outer surface of the front plane light-transmissive substrate, and the backplane comprising a top plane connection; and forming an electrical connection between at least one of the contact spots on the outer surface of the front plane light-transmissive substrate and the top plane connection. The present specification also provides, for example, the following items: (Item 1) An article of manufacture, the article of manufacture comprising, in turn: a light-transmitting substrate having an inner surface and an outer surface opposite the inner surface; A light-transmitting conductive layer; a layer of an electro-optic medium; An adhesive layer; a release sheet in contact with the adhesive layer, the layer of electro-optic medium being disposed between the light transmissive conductive layer and the adhesive layer; The light-transmitting substrate comprises: A continuous portion; a plurality of openings in the continuous portion, the openings comprising a conductive material that forms an electrical connection between the light-transmissive conductive layer and contact spots on the outer surface of the light-transmissive substrate; A manufactured product comprising: (Item 2) Item 1, wherein the continuous portion of the optically transparent substrate comprises a micro-dimpled polymeric material. (Item 3) Item 1, wherein the light transmissive conductive layer comprises a material selected from the group consisting of aluminum tin oxide, indium tin oxide, poly(3,4-ethylenedioxythiophene), and combinations thereof. (Item 4) 2. The article of manufacture of claim 1, wherein the electro-optic medium is an encapsulated electrophoretic medium. (Item 5) Item 1, further comprising a protective layer positioned on the outer surface of the optically transparent substrate. (Item 6) 2. The article of manufacture of item 1, wherein the contact spots have an average diameter of at least 0.1 micrometers and up to 100 micrometers. (Item 7) 2. The article of manufacture of item 1, wherein the contact spots have an average diameter of at least 0.5 micrometers and up to 10 micrometers. (Item 8) Item 2. The article of manufacture of item 1, wherein the contact spots are located on a section of the outer surface of the optically transparent substrate, the section having an average density of at least 10 contact spots per square centimeter to a maximum of 1,000 contact spots per square centimeter. (Item 9) 1. A laminated electro-optic display comprising, in order: a front plane light transmissive substrate having an inner surface and an outer surface opposite the inner surface; A light-transmitting conductive layer; a layer of an electro-optic medium in electrical contact with said conductive layer; a backplane having conductors; Equipped with the front plane light-transmitting substrate comprising a continuous portion and a plurality of openings in the continuous portion, the openings comprising a conductive material that forms an electrical connection between the light-transmitting conductive layer and contact spots on the outer surface of the front plane light-transmitting substrate; Layered electro-optic display. (Item 10) 10. The laminated electro-optic display of claim 9, wherein the continuous portion comprises a micro-dimpled polymeric material. (Item 11) 10. The laminated electro-optic display of claim 9, wherein the electro-optic medium is an encapsulated electrophoretic medium. (Item 12) 10. The laminated electro-optic display of claim 9, further comprising a protective layer positioned on the outer surface of the front plane light-transmitting substrate. (Item 13) 10. The laminated electro-optic display of claim 9, wherein the contact spots have an average diameter of at least 0.1 micrometers and up to 100 micrometers. (Item 14) 10. The laminated electro-optic display of claim 9, wherein the contact spots have an average diameter of at least 0.5 micrometers and up to 10 micrometers. (Item 15) 10. The laminated electro-optic display of claim 9, wherein the contact spots are located on a section of the outer surface of the front plane light-transmitting substrate, the section having an average density of at least 10 contact spots per square centimeter to a maximum of 1,000 contact spots per square centimeter. (Item 16) An optically transparent conductive material, the optically transparent conductive material comprising: a light-transmitting substrate having a first surface, a second surface opposite to the first surface, and a plurality of through holes; a conductive material selected from aluminum oxide, zinc oxide, indium oxide, indium tin oxide, and poly(3,4-ethylenedioxythiophene), in contact with the first surface of the substrate; Equipped with the conductive material forms an optically transparent conductive surface adjacent the first surface of the optically transparent substrate and provides electrical connections through the plurality of through holes to contact spots on the second surface of the optically transparent substrate; The through holes have an average diameter of at least 0.1 micrometers and up to 100 micrometers. Light-transmitting conductive material. (Item 17) Item 17. The optically transparent conductive material according to item 16, wherein the optically transparent substrate is a polymeric material. (Item 18) Item 17. The optically transparent conductive material according to item 16, wherein the through holes have an average diameter of at least 0.5 micrometers to a maximum of 10 micrometers. (Item 19) Item 17. The optically transparent conductive material of item 16, wherein the through holes have a shape selected from the group consisting of circular, linear, and elliptical. (Item 20) Item 17. The optically transparent conductive material of item 16, wherein the contact spots are located on a section of the outer surface of the optically transparent substrate, the section having an average density of at least 10 contact spots per square centimeter to a maximum of 1,000 contact spots per square centimeter. [Brief description of the drawings]

[0025] The drawings depict one or more implementations in accordance with the present concepts, by way of example only, and not by way of limitation, in which like reference numbers refer to the same or similar elements.

[0026] [Figure 1] FIG. 1 is a schematic cross-section through a conventional front plane laminate (FPL).

[0027] [Diagram 2] FIG. 2 is a schematic perspective cross-sectional view through a front plane laminate including an optically transparent substrate of the present invention.

[0028] [Diagram 3] 3A-3C are schematic top plan views of front plane light-transmitting substrates having contact spots of different geometric shapes, according to embodiments of the present invention.

[0029] [Figure 4] 4A-4C are schematic top plan views of a front plane optically transparent substrate featuring elongated contact spots formed in a repeating pattern, according to an embodiment of the invention.

[0030] [Diagram 5] FIG. 5 is a perspective cross-sectional view through a layered electro-optic display according to an embodiment of the invention.

[0031] [Figure 6] FIG. 6 is a perspective cross-sectional view through the laminated electro-optic display of FIG. 5 where electrical connections have been made between the frontplane laminate contact spots and the backplane conductors.

[0032] [Figure 7]FIG. 7 is a schematic top view of a display device made from strips, including the invention described herein, that have been interwoven with fiber fragments to produce a flexible fabric that can be altered to increase or decrease the amount and color of light reflected or transmitted through the fabric on demand. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] (Detailed Description) In the following detailed description, numerous specific details are set forth as examples in order to provide a thorough understanding of the relevant teachings. However, it should be apparent to one skilled in the art that the present teachings may be practiced without such details.

[0034] The present invention includes a light-transmitting substrate having an inner surface, an outer surface opposite the inner surface, and a plurality of through holes. When combined with a light-transmitting conductive material such as indium tin oxide (ITO), the substrate provides electrical connection between a light-transmitting conductive layer that can be used as a top electrode in an electro-optic display and contact spots on the outer surface of the light-transmitting substrate. Thus, the light-transmitting substrate allows for simpler electrical connections for electro-optic displays, especially for large format devices that may need to be cut or assembled on-site. In addition, the redundancy of having tens to hundreds of electrical contacts minimizes the possibility of a device being rendered inoperable due to a broken electrical connection.

[0035] As previously described, the present application provides, in one aspect, a novel article of manufacture (hereafter referred to for convenience as a "front plane laminate" or "FPL") that simplifies the formation of an electrical connection between an upper light-transmitting conductive layer and a voltage source by forming an electrical connection between the upper light-transmitting conductive layer and contact spots on the outer surface of the front plane light-transmitting substrate. The electrical connection may be made in fine holes or vias, or a simple clamp may be applied to the outside, e.g., the outer edge, to create an electrical connection to a portion or all of the outer surface of the front plane light-transmitting substrate. Alternatively, conductive pads or conductive tape can be used to make the connection to the front plane light-transmitting substrate. Alternatively, a front plane light-transmitting substrate with microvias may also provide better conformal capabilities for complex curves. For example, fine holes or strips can be etched into the surface to allow deformation without breaking the connection to the light-transmitting conductive layer. The present invention is particularly useful in simplifying complex structures where multiple connections to a light-transmitting conductive layer are required.

[0036] Reference will now be made in detail to the embodiments illustrated in the accompanying drawings and discussed below. The use of terms such as "top," "bottom," "over," "below," and the like is merely a convention, as the relative locations of two or more layers may be switched by reorienting the article in a different direction.

[0037] Front Panel Laminate

[0038] Before proceeding further, it is desirable to provide an exemplary description of a conventional front plane laminate ("FPL") as shown diagrammatically in the cross-sectional view of Figure 1. FPL 100 is similar to that described, for example, in U.S. Patent No. 10,503,041, which is incorporated herein by reference. FPL 100 may include, in order, a front plane light-transmitting substrate 102, a light-transmitting conductive layer 104 in contact with the inner surface of the front plane light-transmitting substrate, a layer of electro-optic medium 106 in contact with the conductive layer, an adhesive layer 108, and a release sheet 110.

[0039] In many applications, the front plane light-transmitting substrate 102 comprises polyethylene terephthalate (PET) and the light-transmitting conductive layer 104 comprises indium tin oxide (ITO). Such materials are commercially available in large rolls, for example from Saint-Gobain. The light-transmitting conductive layer 104 is applied to the light-transmitting substrate 102, which is typically flexible in the sense that the substrate can be wrapped by hand around a 10 inch (254 mm) diameter drum without permanent deformation, for example.

[0040] The term "light-transmissive" is used throughout this specification and claims to mean that a layer so designated transmits sufficient light to allow an observer looking through the layer to observe changes in the display state of the electro-optic medium that are normally visible through the conductive layer and adjacent substrate; in cases where the electro-optic medium displays changes in reflectance at non-visible wavelengths, the term "light-transmissive" should of course be interpreted to refer to the transmission of the relevant non-visible wavelengths. The substrate 102 may be fabricated from glass or a polymer film, such as polyethylene terephthalate (PET), and may have a thickness ranging from about 20 μm to about 650 μm, more typically from about 50 μm to about 250 μm. The conductive layer is typically a thin layer of a so-called "transparent conductive oxide" such as aluminum oxide, zinc oxide, indium zinc oxide, or indium tin oxide (ITO), or the conductive layer may comprise a conductive polymer such as poly(3,4-ethylenedioxythiophene) (PEDOT). Designs may also include hybrid materials, such as a combination of conductive polymers and conductive oxides, or designs may include dilute amounts of conductive fillers, such as silver whiskers or flakes, or exotic materials, such as nanotubes or graphene. In some embodiments, the substrate 102 may be a rigid optically transparent material, such as glass or clear polycarbonate or acrylic.

[0041] Typically, a coating of electro-optic medium capable of switching between optical states 106 is applied over the conductive layer 104 such that the electro-optic medium 106 is in close proximity to the conductive layer 104. The electro-optic medium is typically characterized as an electrophoretic material including a plurality of charged particles disposed in a fluid and capable of moving through the fluid under the influence of an electric field. The electrophoretic material can be selected such that the front panel laminate achieves alternately and reversibly different states when a suitable electric field is applied, for example, the electrophoretic medium may be switched between transparent and opaque, or color 1 and color 2, or transparent and color 1 and color 2.

[0042] In an exemplary embodiment, the electro-optic medium may be in the form of an oppositely charged dual particle encapsulation medium. Such an encapsulation medium includes a number of small capsules, each of which itself comprises an internal phase containing electrophoretically mobile particles suspended in a liquid suspension medium, and a capsule wall surrounding the internal phase. Typically, the capsules themselves are held in a polymer binder to form a coherent layer. When the coherent layer is positioned between two electrodes, the optical state can be reversed with the presence of a suitable electric field. The suspension medium may include a hydrocarbon-based liquid in which negatively charged white particles and positively charged black particles are suspended. In such an embodiment, upon application of an electric field across the electro-optic medium, the white particles may migrate to the positive electrode and the black particles may migrate to the negative electrode, such that the electro-optic medium 106 appears white or black to an observer viewing the display through the substrate 102, depending, for example, on whether the conductive layer 104 is positive or negative with respect to the backplane at any point in the final display. Electro-optic medium 106 alternatively comprises a plurality of colored particles in addition to black and / or white particles, each color having its respective charge polarity and intensity.

[0043] A layer of lamination adhesive 108 may be coated over the electro-optic medium layer 106, and a release layer 110 may be applied over the adhesive layer 108. The release sheet may be of any known type, provided, of course, that it does not contain materials that may adversely affect the properties of the electro-optic medium, and numerous suitable types of release sheets will be known to those skilled in the art. Common release sheets include a substrate such as paper or a plastic film, for example, a PET film that is about 150 μm to about 200 μm thick and that has been coated with a low surface energy material, for example, silicone. In some cases, the release sheet is metallized to allow for the application of an electrical potential across the electro-optic medium so that functionality can be assessed during assembly of a downstream product.

[0044] 2, a novel front plane laminate (designated as 100A) according to one aspect of the present invention is illustrated. The FPL is substantially similar to the laminate 100 shown in FIG. 1, except that a front plane light-transmitting substrate 102 having an inner surface 112 and an outer surface 114 opposite the inner surface is characterized by a composite structure including a continuous portion 102a and a plurality of openings 102b distributed within the continuous portion 102a. The openings 102b include a conductive material 115 that forms an electrical connection between the conductive layer 104 and one or more contact spots 116 on the outer surface 114. Optionally, the conductive layer 104 may be segmented into two or more sections, each in contact with a subset of the contact spots (not shown), resulting in an architecture in which a short circuit in one section does not simultaneously result in failure of the other sections. The electrical connections may be applied locally or to the entire exterior surface, and a protective layer (not shown), such as a coating of a clear acrylic polymer or silicone, may be added to seal some or all of the contact spots to prevent unwanted shorts after assembly while providing a moisture barrier.

[0045] In an exemplary embodiment, the continuous portion 102a may be fabricated from glass or a polymer film, such as polyethylene terephthalate (PET), which is subjected to etching, cutting, laser ablation, or any applicable drilling technique to leave openings. Alternatively, the continuous portion 102a may be micro-indented to create through holes or structural valleys that can be filled during a sputtering process where a conductive material such as ITO is added. Alternatively, the PET film may be softened with heat, stretched over a form, and perforated using a jet of high pressure gas. A conductive material may then be used to fill the openings and form the contact spots 116. The openings may be provided in various shapes, sizes, and densities as is suitable for the application at hand. Regardless of the shape, the individual and average spot sizes may be defined in terms of a given spot dimension. Unless otherwise provided or clear from the context, the term "dimension" refers to the length, width, or diameter of the contact spot along the surface of the layer. Typically, "length" refers to the extension in a lengthwise direction and width refers to the extension in a widthwise direction. "Diameter," when used in reference to a contact spot, is intended to identify the longest straight line segment between two points on the spot along the outer surface of the front plane optically transparent substrate. In some non-exclusive embodiments, the geometry of the contact spots 116 is such that their average diameter is in the range of about 0.1 μm to about 100 μm. In additional embodiments, the average contact spot diameter is in the range of about 0.5 μm to about 10 μm.

[0046] A front plane light-transmitting substrate 102 having circular geometric contact spots 116 that can be fabricated by microetching a polymer film substrate to form rounded openings is illustrated in a schematic top view in FIG. 3A. Exemplary average recess diameter ranges include about 10 μm to about 100 μm, about 10 μm to about 75 μm, and about 10 μm to about 50 μm. FIG. 3B illustrates a substrate microetched to produce stripe-shaped openings having an average width equal to or less than 100 μm. Exemplary average stripe width ranges include about 1 μm to about 100 μm, about 2 μm to about 75 μm, and about 5 μm to about 50 μm. Another substrate microetched to form elliptical openings having an average minor axis length equal to or less than about 100 μm is depicted diagrammatically in FIG. 3C. Exemplary ranges of the average minor axis length include about 1 μm to about 100 μm, about 5 μm to about 75 μm, and about 10 μm to about 50 μm.

[0047] The various contact spot shapes, surface density of contact spots, and spatial arrangements may be specifically engineered to improve the ability of the front panel laminate to adopt complex and curved shapes without breaking electrical connections while maintaining the structural integrity of the electro-optic medium. In some embodiments, the conductive material may be deposited into the openings after the continuous phase is drilled and shaped to accommodate the desired geometry and density of contact spots. One or more sections of the front plane light-transmitting substrate may be prepared in this manner to provide individualized architectures to serve different types of applications. As illustrated in the schematic top plan view of FIG. 4A, the elongated contact spots 116 may be formed in a repeating pattern at the edge of the front plane light-transmitting substrate 102. In FIG. 4B, the pattern is also repeated at the center of the front plane light-transmitting substrate, while that of FIG. 4C features a pattern of different size and relative orientation. This approach allows the fabrication of front panel laminates with specifically designed geometry and patterns of contact spots to suit any type of application. The contact spots 116 may be formed to be located within a particular section of the front plane optically transparent substrate 102 within a density range suitable for the application at hand. In an exemplary embodiment, the section of the front plane optically transparent substrate 102 includes contact spots 116 at a density within a range of about 10 contact spots per square centimeter to about 1,000 contact spots per square centimeter. In another embodiment, the section of the front plane optically transparent substrate 102 includes contact spots 116 at a density within a range of about 50 contact spots per square centimeter to about 500 contact spots per square centimeter. Embodiments in which the density is from about 50 contact spots per square centimeter to about 250 contact spots per square centimeter are also contemplated.

[0048] Front Panel Laminate Manufacturing

[0049] As explained above, the contact spots 116 may be formed by introducing a conductive material 115 into the openings 102b present in the continuous portion 102a of the front plane light-transmitting substrate 102. As explained above, the openings 102b may be recesses made by removing a portion of a polymer layer. In an embodiment, a film of a flexible light-transmitting polymer (e.g., PET) may be recessed, drilled, ablated, etc., to form a plurality of openings. The flexible light-transmitting polymer may then be coated with a light-transmitting conductive material (e.g., ITO), for example, through sputtering. When the light-transmitting material is coated on the inner surface, the openings 102b are also filled with the light-transmitting conductive material, providing an electrical connection to the outer surface 114 of the front plane light-transmitting substrate (PET film). The openings 102b are small, and because both the substrate 102 and the conductive material 115 are light-transmitting, the conductive material 115 is not visually obstructive. In another embodiment, a flowable conductive material precursor, such as a solution or paste, is introduced into the opening and then cured to provide electrical connections and contact spots. Depending on the relatively small diameter of the opening and the viscosity of the precursor, this process may prove difficult to perform in practice. To overcome these difficulties, suction may be applied to improve the flow of the precursor, and a surfactant may be added to the precursor to reduce the surface tension with the surface of the opening. In a further non-exclusive embodiment, the conductive material 115 and / or its precursor may be magnetizable, in which case this may assist in filling the opening with the material. In an exemplary embodiment, the same microfabrication methods used to manufacture microvias in high density interconnect (HDI) multilayer printed circuit boards (PCBs) may be used, for example, by adding layers in successive times, when performed in sequential build (SBU) manufacturing techniques with copper or other conductive materials such as carbon or carbon nanotubes. In a further embodiment, the conductive material may be applied by electroplating techniques.

[0050] More broadly, the interspersed portion does not necessarily have to be formed by introducing conductive fillers into the openings in the continuous portion. In some embodiments, the front plane light-transmitting substrate may be manufactured by combining insulating and conductive materials in an anisotropic manner, thereby creating electrical connections and interspersing corresponding conductive spots in the continuous portion. In one representative example, the front plane light-transmitting substrate may be fabricated by interweaving conductive yarns with PET fibers, such as PET coated with a conductive material, e.g., a metal or a conductive polymer such as polyaniline (PANI). Throughout the manufacturing process, the conductive yarns are selectively included in areas of the front plane light-transmitting substrate where electrical connections and contact spots are intended to be formed.

[0051] All of the above approaches assume that the contact spots are formed before the front plane light-transmitting substrate is assembled with the rest of the front plane laminate, however, in some embodiments, the conductive material may be introduced after the FPL is assembled, provided that the conductive material precursor does not flow through the electro-optic medium and short it out.

[0052] Electro-optical displays

[0053] In one application, the frontplane laminate is laminated to a backplane to form an electro-optic display. There are three main categories of backplanes: active matrix, passive matrix, and direct drive backplanes.

[0054] For an active matrix backplane, an array of thin film transistors (TFTs) (not shown) is formed on the surface of the backplane substrate 202, with each transistor acting as a switch for a pixel electrode (212a, 212c). The TFTs are addressed by a set of narrow multiplexed electrodes (gate and source lines). A passive matrix backplane uses a simple grid to deliver charge to specific pixels on the display. The grid is formed on a top and bottom substrate. One substrate forms the "columns" and the other substrate forms the "rows". In a passive matrix, the columns or rows are made from a transparent conductive material, usually indium tin oxide (ITO). The rows or columns are connected to an integrated circuit that controls when charge is sent to a particular column or row. In a direct drive backplane, the bottom substrate may include an electrical connector located on the edge of the substrate, with multiple conductors extending from the edge of the substrate to form contacts to sections of the segmented conductive layer, such that each section is electrically connected to a respective conductor. There are no limitations on the type of backplane that may be used in various embodiments of the present invention, provided that the top plane connections are made through contact spots disposed on the outer surface of the front plane light-transmitting substrate.

[0055] Turning now to FIG. 5, assembly of an electro-optic display using FPL 100 with a backplane may be effected by removing release sheet 110 and contacting adhesive layer 108 with backplane 200 under conditions effective to adhere the adhesive layer to a backplane such as 200, thereby affixing the adhesive layer, layer of electro-optic medium 106, and light-transmissive conductive layer 104 to the backplane. FPL 100 may be cut larger than the final display size, or may even be a continuous sheet such as in a roll-to-roll process. This allows for coarse tolerances in the alignment of FPL 100 and backplane 200, which is particularly useful for large displays. Once laminated (not shown), the display may be cut to its final size, potentially using alignment marks or pins on the backplane to allow for precise alignment of the cut to the backplane.

[0056] Lamination of the FPL 100 of 200 to the backplane may advantageously be performed by vacuum lamination. Vacuum lamination is effective in evacuating air from between the two materials being laminated, and thus in avoiding undesirable air bubbles in the final display (such air bubbles may introduce undesirable artifacts in the image produced on the display). However, vacuum lamination of the two parts of an electro-optic display in this manner may impose stringent requirements on the lamination adhesive used, especially for displays using encapsulated electrophoretic media. The lamination adhesive 108 should have sufficient adhesive strength to bond the electro-optic layer to the backplane, and in the case of encapsulated electrophoretic media, the adhesive 108 should also have sufficient adhesive strength to mechanically hold the capsules together. The adhesive 108 is preferably chemically compatible with all other materials in the display. If the electro-optic display is of the flexible type, the adhesive 108 should be sufficiently flexible so as not to introduce defects in the display when the display is flexed. The lamination adhesive 108 should have proper flow properties at the lamination temperature to ensure a high quality lamination. Furthermore, the lamination temperature is preferably as low as possible. An example of a useful lamination adhesive that may be incorporated within various embodiments of the present invention is an aqueous polyurethane dispersion known as a "TMXDI / PPO" dispersion, as described in U.S. Pat. No. 7,342,068, which is incorporated herein by reference in its entirety.

[0057] The top plane connections 204 may be electrically connected to all or a specific subset of the conductive spots 116. Typically, the top plane connections 204 from the backplane are integrated into the backplane 200, which is depicted as a standalone item in Figs. 5 and 6 for clarity. In a representative embodiment, this connection may be accomplished using wires or traces (304 / 306) or a combination thereof, as shown diagrammatically in Fig. 6. It is not necessary to connect each conductive spot 116 to a top plane connection 204, since each conductive spot 116 is connected to the light-transmitting conductive layer 104. However, typically more than one conductive spot is connected. In some cases, conductive traces are applied across the outer surface as illustrated in Fig. 6, with conductive transparent wiring 304 linking a subset of the contact spots to the conductors 306 and the backplane connections 204. In such an embodiment, a protective layer, such as a clear coating of acrylic or silicone, can isolate the connection points and prevent undesired shorting after assembly (not shown). In an alternative embodiment, the conductive contact pads that are coupled to the wires 304 can be attached to the outer surface using, for example, a conductive adhesive. In other embodiments, the connection between the top plane connections 204 and the conductive spots 116 can be made using conductive clamps, for example, alligator clips.

[0058] Flexible, color-changing and transparent coating material

[0059] In further applications, the front plane laminate may be cut into pieces, which are sealed and then interwoven with pieces of conventional (e.g., textile, polymer) materials, for example. Alternatively, strips of one or more types of front plane laminate 100 may be interwoven with fiber strips 700 to form a woven structure of fibers 700 and front plane laminate 100. In an exemplary fabric, shown diagrammatically in FIG. 7, FPL strips 100 are interwoven with fiber strips 700 to produce a flexible fabric that is not completely transparent, but can be altered to increase or decrease the amount and color of light reflected or transmitted through the fabric, as required. Alternatively, both orientations of the fabric may be achieved with strips of front plane laminate 100. A variable color and transmission coating with this type of architecture is described in U.S. Pat. No. 11,086,186, which is incorporated by reference in its entirety. However, as anticipated above, to make electrical contact with a conductive layer in a conventional laminate, it is usually necessary to provide at least one "connection area" where the conductive layer is free from the electro-optic medium. As a result, each FPL strip in the fabric requires its own individual connection area, which leads to structurally complex structures that are relatively expensive and laborious to manufacture.

[0060] In the structure of FIG. 7, making electrical contacts is greatly simplified for FPL strips 100 made from the novel laminate as disclosed herein. Contact spots 116 on the upper surface of the optically transparent substrate 102 can be easily connected to the conductive layer of a given strip by applying conductive clamps or by laying down wires or traces. The mix of electro-optic and conventional materials in the woven fabric need not be in a 1:1 ratio as shown in FIG. 7. For example, the variable transmission structure may include 10 times more surface area of ​​electro-optic material than conventional material. Alternatively, the variable transmission structure may include 10 times more surface area of ​​conventional material than electro-optic material. Of course, intermediate ratios such as 5:1, 3:1, 2:1, 1:1, 1:2, 1:3, 1:5, etc. are also possible. In other embodiments, the variable transmission structure may include two different types of electro-optic material interwoven similar to FIG. 7. Woven fabric materials including three or more electro-optic materials are also envisioned. In one example, FPL strips containing bistable, reflective, or variably transmitting materials may be woven together with conventional fibers. In another embodiment, variably transmitting strips may be woven together to form a flexible fiber that can be switched between light transmitting and colored states.

[0061] While preferred embodiments of the present invention have been shown and described herein, it should be understood that such embodiments are provided by way of example only. Numerous variations, modifications, and substitutions will occur to those skilled in the art without departing from the spirit of the present invention. It is therefore intended that the appended claims cover all such variations as fall within the spirit and scope of the present invention. All of the contents of the aforementioned patents and applications are incorporated herein by reference in their entirety. In the event of a conflict between the contents of this application and any of the patents and applications incorporated herein by reference, the contents of this application shall control to the extent necessary to resolve such conflict.

Claims

1. An article of manufacture, the article of manufacture comprising, in turn: a light-transmitting substrate having an inner surface and an outer surface opposite the inner surface; a continuous light-transmissive conductive layer; a layer of an electro-optic medium; An adhesive layer; a release sheet in contact with said adhesive layer, said layer of electro-optic medium being disposed between said continuous light-transmissive conductive layer and said adhesive layer; The light-transmitting substrate comprises: A continuous portion; a plurality of openings in the continuous portion, each of the plurality of openings comprising a conductive material formed from the same material as the continuous light-transmissive conductive layer, thereby providing an electrical connection between the continuous light-transmissive conductive layer and electrical contact spots on the outer surface of the light-transmissive substrate; A manufactured product comprising:

2. The article of manufacture of claim 1 , wherein the continuous portion of the optically transparent substrate comprises a micro-dimpled polymeric material.

3. 10. The article of manufacture of claim 1, wherein the continuous light-transmissive conductive layer comprises a material selected from the group consisting of aluminum tin oxide, indium tin oxide, poly(3,4-ethylenedioxythiophene), and combinations thereof.

4. 10. The article of manufacture of claim 1 wherein said layer of electro-optic medium is an encapsulated electrophoretic medium.

5. The article of manufacture of claim 1 , further comprising a protective layer positioned on the outer surface of the optically transparent substrate.

6. 10. The article of manufacture of claim 1, wherein the electrical contact spots have an average diameter of at least 0.1 micrometers and up to 100 micrometers.

7. 10. The article of manufacture of claim 1, wherein the electrical contact spots have an average diameter of at least 0.5 micrometers and up to 10 micrometers.

8. 2. The article of manufacture of claim 1, wherein the electrical contact spots are located on a section of the outer surface of the optically transparent substrate, the section having an average density of at least 10 electrical contact spots per square centimeter to a maximum of 1,000 electrical contact spots per square centimeter.

9. 1. A laminated electro-optic display comprising, in order: a front plane light transmissive substrate having an inner surface and an outer surface opposite the inner surface; a continuous light-transmissive conductive layer; a layer of electro-optic medium in electrical contact with said continuous light-transmissive conductive layer; a backplane having conductors; Equipped with the front plane light-transmitting substrate comprises a continuous portion and a plurality of openings within the continuous portion, each of the plurality of openings comprising a conductive material formed from the same material as the continuous light-transmitting conductive layer, thereby providing an electrical connection between the continuous light-transmitting conductive layer and electrical contact spots on the outer surface of the front plane light-transmitting substrate; Layered electro-optic display.

10. 10. The laminated electro-optic display of claim 9, wherein the continuous portion of the front plane light transmissive substrate comprises a micro-dimpled polymeric material.

11. 10. A laminated electro-optic display as claimed in claim 9, wherein said layer of electro-optic medium is an encapsulated electrophoretic medium.

12. 10. The laminated electro-optic display of claim 9 further comprising a protective layer positioned on the outer surface of the front plane light-transmitting substrate.

13. 10. The laminated electro-optic display of claim 9, wherein the electrical contact spots have an average diameter of at least 0.1 micrometers and up to 100 micrometers.

14. 10. The laminated electro-optic display of claim 9, wherein the electrical contact spots have an average diameter of at least 0.5 micrometers and up to 10 micrometers.

15. 10. The laminated electro-optic display of claim 9, wherein the electrical contact spots are located on a section of the outer surface of the front plane light-transmitting substrate, the section having an average density of at least 10 electrical contact spots per square centimeter to up to 1,000 electrical contact spots per square centimeter.

16. An optically transparent conductive material, the optically transparent conductive material comprising: a light-transmitting substrate having a first surface, a second surface opposite to the first surface, and a plurality of through holes; a continuous conductive material selected from aluminum oxide, zinc oxide, indium oxide, indium tin oxide, and poly(3,4-ethylenedioxythiophene), in contact with the first surface of the optically transparent substrate; Equipped with the continuous conductive material forms an optically transparent conductive surface adjacent the first surface of the optically transparent substrate, provides electrical connections through the plurality of through holes to electrical contact spots on the second surface of the optically transparent substrate, and fills the plurality of through holes; The through holes have an average diameter of at least 0.1 micrometers and up to 100 micrometers. Light-transmitting conductive material.

17. 20. The optically transparent conductive material of claim 16, wherein the optically transparent substrate is a polymeric material.

18. 17. The optically transparent conductive material of claim 16, wherein the through holes have an average diameter of at least 0.5 micrometers and up to 10 micrometers.

19. 17. The optically transparent conductive material of claim 16, wherein the through holes have a shape selected from the group consisting of circular, linear, and elliptical.

20. 17. The optically transparent conductive material of claim 16, wherein the electrical contact spots are located on a section of the second surface of the optically transparent substrate, the section having an average density of at least 10 electrical contact spots per square centimeter to a maximum of 1,000 electrical contact spots per square centimeter.

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