TWI821598B - Light-transmissive conductor with directional conductivity and method of making the same - Google Patents

Abstract

Light-transmissive conductors including oriented conductors disposed in a light-transmissive polymer having a volume resistivity between 1x10¹⁰ ohm-cm and 1x10⁴ ohm-cm. The oriented conductors typically have very high conductivity along their length. Light-transmissive conductors described herein are well-suited for front electrodes for electro-optic displays, especially elongated displays in the shape of ribbons, stripes, or rulers.

Description

Light-transmitting conductor with directional conductivity and manufacturing method thereof

This application claims priority from U.S. Patent Provisional Application No. 63/004,430 filed on April 2, 2020. This application additionally claims priority from U.S. Patent Application No. 16/585,218 filed on September 27, 2019. All patents, published applications and references disclosed herein are incorporated by reference in their entirety.

In reflective display media, most images are produced using only reflected ambient light. It is therefore important to minimize light losses in the optical path between the luminescent source (eg daylight) and the reflective medium. This is particularly important for the film that makes up the front electrode (light passes through it twice before reaching the viewer). For example, polyethylene terephthalate (PET) coated with 5 mil thick commercially available indium tin oxide (ITO) has a conductivity of 300 ohms/square and a transmission spectrum of visible light of about 85% for a single pass. Therefore, after two passes through the film, the transmission actually drops to (0.85) ² , or 72%. In other words, more than a quarter of the incident light "disappears" in front of the viewer on its journey from the light source to the medium to the viewer's eyes.

This loss in transmittance is detrimental to all types of reflective optoelectronic displays because almost 30% of the light may be lost even before losses in the display medium are taken into account. Therefore, in many cases, the reflective medium must be supplemented with front light, which "intensifies" the light hitting the reflective medium. This light is commonly seen in e-readers, watches, thermostats, etc.

In addition to losses, PET-ITO is prone to cracking when bent, making it unsuitable for many applications that require flexible transparent conductors. Many novel electrode materials have been developed to replace ITO, but most are currently too expensive for commercial manufacturing or not robust enough for consumer products. Some of these light-transmitting materials are dispersions of small conductors (silver shavings or whiskers) in a polymeric binder that provides conductive continuity as well as flexibility and mechanical strength. See, for example, U.S. Patent No. 9,529,240, which is incorporated herein by reference in its entirety. In most cases, the adhesive is an electrical insulator, thus causing a non-uniform electric field between the light-transmissive composite electrode and another electrode (such as the backplane conductor) in the system. When this light-transmissive composite electrode is used in an electrophoretic medium (such as that sold by E Ink Corporation), this unevenness causes a transient state switching problem, generally known as "self-erasing", so that part of the updated image will be lost after the display is updated. disappear. This unevenness can be improved by increasing the amount of small conductors in the formulation, however, as the amount of conductor dispersion increases, the transmittance of the ultimately light-transmitting conductive layer decreases.

The requirements for suitable light-transmissive conductors are more complex when the conductor shape is of high aspect ratio. That is, when the length to width ratio (aspect ratio) is greater than 10:1, such as 20:1, such as 50:1, such as 100:1. This aspect ratio is common in long display segments such as shelf marquees, strips, fabrics, or architectural design elements such as pinstripes. In this application, the minimum sheet resistance of, for example, ITO-coated PET (300 ohms/square) is significant enough to dramatically increase the power required to actuate the display. This results in more failures of the device and requires more expensive power management components. In addition, many high-aspect-ratio applications (such as ribbons) require greater flexibility, which is difficult to achieve with existing light-transmissive conductors.

Therefore, the invention mentioned here provides a light-transmitting conductor with directional conductivity. In preferred embodiments, the conductivity along the length of the material is approximately that of an electrically conductive material, such as less than 1 x 10 ^-3 ohm-centimeter. [It should be understood that the volume resistivity quoted is for standard relative humidity (50% RH) and temperature (20°C). ]

A first aspect of the invention includes a light-transmissive conductor comprising a light-transmissive polymer with a volume resistivity between 1x10 ¹⁰ ohm-cm and 1x10 ⁴ ohm-cm and an aspect ratio greater than 10:1 (length:width) oriented conductive components. In some embodiments, the light-transmissive polymer is flexible, thereby allowing the light-transmissive conductor to be flexible. In some embodiments, the light-transmissive polymer is doped with conductive additives, such as salt, polymer electrolyte (polyelectrolyte), polymer electrolyte (polymer electrolyte), or solid electrolyte. In some embodiments, the directional conductive element is a lead or conductive fiber. In other embodiments, the oriented conductive element includes a plurality of conductive sheets, wires, silver, whiskers, nanowires, or nanotubes oriented such that the aspect ratio is greater than 10:1. This material may include carbon nanotubes, silver, tungsten, iron, copper, nanoparticles, metal mesh, or graphene. In some embodiments, the directional conductive element has an aspect ratio greater than 100:1. In some embodiments, the visible light transmittance of the light-transmissive polymer is greater than 70%. All of the above features can be brought into light-transmitting films with a thickness of less than 500 microns.

A second aspect of the invention includes an optoelectronic display, which includes a front electrode including a layer of the light-transmitting conductor of the invention; a back electrode; a layer of photoelectric medium disposed between the front electrode and the back electrode; and connecting the front and back electrodes. the voltage source. The light-transmitting conductor includes a light-transmitting polymer with a volume resistivity between 1x10 ¹⁰ ohm-cm and 1x10 ⁴ ohm-cm, and a directional conductive element with an aspect ratio greater than 10:1 (length:width). In some embodiments, the photoelectric medium layer includes charged pigment particles in a solvent. In some embodiments, the charged pigment particles and solvent are encapsulated in microcapsules or sealed in microcells. The charged pigment particles may include two groups of charged pigment particles, each group having a different charge polarity and different optical characteristics. In some embodiments, the optoelectronic display includes an optically clear adhesive between the front electrode and the optoelectronic layer.

A third aspect of the invention includes a color-changing fiber comprising a central conductive element; a layer of optoelectronic media surrounding the central conductive element; and a light-transmissive conductive outer layer of the invention comprising a volume resistivity of 1x10 ¹⁰ ohm-cm to 1x10 ⁴ ohm-cm, and directional conductive components with an aspect ratio greater than 10:1 (length:width). In some embodiments, the photoelectric medium includes charged pigment particles in a solvent. In some embodiments, the charged pigment particles are encapsulated in microcapsules and dispersed in a polymeric binder.

A fourth aspect of the invention includes a method of making a light-transmissive conductor of the invention, which includes providing a light-transmissive polymer with a volume resistivity between 1x10 ¹⁰ ohm-cm and 1x10 ⁴ ohm-cm, and having an aspect ratio greater than 10 :1 (length:width) directional conductive elements are arranged in the light-transmitting polymer. In some embodiments, the method further includes disposing a plurality of the directional conductive elements in the light-transmissive polymer, orienting the plurality of directional conductive elements with an external stimulus, and curing the light-transmissive polymer. The external stimulus can be a magnetic field, an electric field, light, or mechanical actuation. In some embodiments, the resulting light-transmissive conductor has a conductivity of less than 1 x 10 ^-3 ohm-centimeter in the direction orienting the plurality of directional conductive elements.

These and other aspects of the invention will be apparent from the following description.

The light-transmissive conductors disclosed here have conductivity similar to "normal" metal conductivity in the longer direction, but not in the lateral direction. Therefore, the light-transmitting conductor of the present invention avoids electrical transients that cause self-erasure and other undesirable phenomena in optoelectronic displays. These features are accomplished by including directional conductors in a light-transmitting polymer with a volume resistivity between 1x10 ¹⁰ ohm-cm and 1x10 ⁴ ohm-cm. The conductivity of the directional conductors is typically very high, metal-like, and they can be opaque, requiring 80% or more open space between conductors to give the macroscopic appearance of a transparent conductor. Example materials include carbon nanotubes, metal nanowires (such as silver, tungsten, stainless steel, or copper), printed metal nanoparticles, metal mesh, and graphene. The configuration can be a simple lead oriented only in the fiber direction, or it can have continuous conductivity in the fiber direction and some lateral conductivity as well.

The light-transmissive polymer (also known as the polymeric dispersion binder layer) is a doped polymeric layer that fills the spaces between the conductor regions of the composite transparent electrode. This layer is transparent. Typically, the thickness of the resulting light-transmissive conductor is between 5 and 50 microns. The function of the light-transmissive polymer is to separate the individual directional conductors with sufficient width so that the resulting light-transmissive conductor achieves a visible light transmittance of over 80%, while allowing the electrical drive signals in the leads to share some of the conductivity between the directional conductors. , but are not completely conductive or completely insulating.

The oriented composite transparent electrode of the present invention can be used as a viewing electrode for an electrophoretic display. The electrode can use various standard steps disclosed in the aforementioned E Ink patent to coat or laminate the electrophoretic medium on the electrode to create multiple structures, including but not limited to a simple ink stack as shown in the following figure.

In the following detailed description, many specific details are exemplified in order to provide a complete understanding of the relevant teachings. However, those skilled in the art should understand that these teachings may be practiced without such details.

The term "optoelectronic" as applied to materials is used herein in its conventional sense in the imaging arts to mean a material having at least one first and second display state that differ in optical properties, which material changes from its display state as a result of the application of an electric field to the material. The first changes to its second display state. Although the optical property is generally color perceptible to the human eye, it can also be other optical properties, such as optical transmittance, reflectance, or brightness.

The light-transmissive polymeric material can be any polymeric material that meets the specific requirements of the end-use application. Examples of suitable polymeric materials include polyurethane, vinyl acetate, vinyl acetate ethylene, epoxy, polyacrylic adhesive, or combinations thereof. These adhesive materials can be solvent-based or water-based. Examples of specific polyurethanes that may be used are disclosed in U.S. Patent No. 7,342,068, issued March 11, 2008 and assigned to Air Products and Chemicals, Inc., which is incorporated herein by reference in its entirety.

The light-transmissive polymeric material itself can be a composite, such as an ion-conducting polymer, in which one type of ion can move through the polymeric material and the other cannot. This type of ionic material prevents ions from diffusing out of the polymeric material and potentially damaging other layers into which the ions diffuse (such as organic semiconductor layers).

It is now desirable to select ionic materials so that the conductivity of the final polymeric material after drying can be modified and adjusted by varying the carboxylic acid content of the polyurethane, and also by the cations used. For example, at a given carboxylic acid content, the carboxyl groups on the polyurethane can be neutralized with quaternary ammonium hydroxide, and the expected conductivity increases in the following order: tetramethylammonium < tetraethylammonium < tetrabutylammonium, etc. Phosphonium salts can also be used and should be slightly more conductive than nitrogen-containing analogues due to the larger size of the central atom. Other cationic species (eg metal complex ions) may also be used for this purpose. The solubility of ionic materials in polymeric materials is not an issue in this method because the ions are an intrinsic part of the medium and therefore do not phase separate into separate crystalline phases.

The acidic component of the polymeric material can also be made more acidic by replacing the carboxylic acid component with a group with a higher dissociation constant, such as a sulfate monoester, a sulfonic acid, a sulfinic acid, a phosphonic acid, a phosphonite group, or a phosphate ester. , as long as there is at least one dissociable proton. Quaternary salts and other large cations are still expected to be most useful as counter ions due to their large size and relatively high degree of ion dissociation in dry binder media of low polarity. Nitrogen-based acids (eg _RSO2 -NH- _SO2R ) can also be used if sufficient electron-withdrawing functionality is attached. Almost any mobile ion can be used in this case, including tertiary ammonium, since mobile ions exist in protonated form, even in dry adhesives. However, mobile ions based on larger amines (eg, those with longer alkyl tails) are still preferred because their size is effectively larger and therefore the ion pairs containing them are more dissociable. Alternatively, a carboxylate on the polymer can be used as a mobile ion that is not a strong Brünnster acid, ie it does not have acidic protons, like the quaternary cations discussed above.

Polymeric materials in which the cation is a fixed ion can be made by using quaternary ammonium groups in the polymer backbone or as side chains, and preferably using large anions (such as hexafluorophosphate, tetrabutylborate, tetraphenylborate Salt, etc.) are constructed as mobile ions. The quaternary ammonium group may be substituted by phosphonium, sulfonium, or other cationic groups without dissociable hydrogen, including those formed by metal cation complexes. Examples of the latter include polyether/lithium ion-containing complexes, especially cyclic polyethers (eg 18-crown-6), or polyamine complexes with transition metal ions. In this case, the anionic mobile ions may include the ion forms listed above, plus more basic materials such as carboxylate groups or even phenates.

Alternative stationary cationic polymeric materials include polymers containing repeating units derived from basic monomers, such as poly(vinylpyridine), poly(beta-dimethylaminoethyl acrylate), etc., and copolymers containing such groups , binds to mobile anions that are not good Brenister acceptors (such as sulfonate, sulfate, hexafluorophosphate, tetrafluoroborate, di(methanesulfonyl)imide, phosphate, phosphonic acid salt, etc.). Quaternary ammonium salts derived from this amine monomer can also be used, such as poly(N-methyl or benzyl (vinylpyridinium salt)), poly(N-alkyl (or alkaryl)-N'- Vinylimidazole salt), and poly(acrylic acid or methacrylic acid (β-trimethylammonium ethyl ester)) salt, and vinyl copolymers containing these ionic groups. As before, larger mobile ions are better.

These chemical modification techniques are not strictly limited to polyurethanes and can be applied to any structurally appropriate polymer. For example, vinyl polymers may contain anionic or cationic fixed ions. In another form of the invention, the polymeric material may contain one or more conductive polymers selected from the group consisting of PEDOT-PSS, polyacetylene, polyphenylene sulfide, polyphenylene vinylene, and combinations thereof.

The light-transmitting polymer may alternatively include ionic additives, such as (a) salts, polymer electrolytes, polymer electrolytes, solid electrolytes, and combinations thereof; or (b) non-reactive solvents, conductive organic compounds, or its combination.

In one form, the additive may be a salt, such as an inorganic salt, an organic salt, or a combination thereof, as disclosed in U.S. Patent No. 7,012,735, filed on March 26, 2004 and assigned to E Ink Corporation. Exemplary salts include potassium acetate and tetraalkylammonium salts, especially tetrabutylammonium salts, such as chloride. Further examples of salts include salts such as RCF ₃ SOF ₃ , RClO ₄ , LiPF ₆ , RBF ₄ , RAsF ₆ , RB(Ar) ₄ , and RN(CF ₃ SO ₂ ) ₃ , where R can be any cation, such as Li ⁺ , Na ⁺ , H ⁺ , or K ⁺ . Alternatively R may include an ammonium group of the form N ⁺ R ₁ R ₂ R ₃ R ₄ . A preferred salt is tetrabutylammonium hexafluorophosphate.

In another form, the additive may be a salt having an anion containing at least three fluorine atoms, as disclosed in U.S. Patent No. 8,446,664, assigned to E Ink Corporation, filed on April 4, 2011. The salt may, for example, have a hexafluorophosphate anion. The salt may also have an imidazolium cation. Exemplary salts include 1-butyl-3-methylimidazolium hexafluorophosphate (hereinafter referred to as "BMIHFP"), 1-butyl-3-methylpiperidinium hexafluorophosphate, 1-butyl-hexafluorophosphate 3-methylpyridinium salt, 1-ethyl-3-methylimidazolium hexafluorophosphate, sodium hexafluorophosphate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, and boron tetrafluoride 1 -Butyl-3-methylimidazolium salt. A preferred salt is BMIHFP. This preferred salt is liquid at 25°C and can be directly dispersed in an aqueous polymer dispersion or emulsion without the use of any solvent. Alternatively, since the preferred salts are soluble in water at about 1% at 25°C, they can be added as dilute aqueous solutions. Adding the salt as an aqueous solution avoids introducing any undesirable organic solvents into the adhesive.

Alternatively, the fluorine-containing salt may have a tetrafluoroborate anion, a tetraphenylborate anion, a trifluoromethane sulfonamide anion ("triflimide"), a tetrakis(pentafluorophenyl)borate anion, a ,5-(trifluoromethyl)phenyl)borate anion, or trifluoromethanesulfonate anion ("triflate"), such as boron tetrafluoride 1-butyl-3-methylimidazolium salt or trifluoride 1-Butyl-3-methylimidazolium methanesulfonate. The fluoride-containing salt may be present in an amount from about 50 to about 10,000 ppm, and typically from about 100 to about 1000 ppm, based on the polymeric material solids content.

In other specific embodiments, the polymer electrolyte is a polymer electrolyte. Polymer electrolytes are generally polymers in which about 10% or more of the molecules are composed of functional groups that can be ionized to form charged species. Examples of specific functional groups in polymer electrolytes include, but are not limited to, carboxylic acid, sulfonic acid, phosphoric acid, and quaternary ammonium compounds. These polymers may be combined with organic or inorganic salts or used alone. Examples of polymer electrolytes include, but are not limited to, polyacrylic acid, polystyrene sulfonate, poly(2-vinylpyridine), poly(4-vinylpyridine), poly(dimethylammonium chloride), poly(methylammonium chloride), Dimethylaminoethyl acrylate), poly(diethylaminoethyl methacrylate), and may include salts of polymeric acids, such as, but not limited to, alkali metal salts of polyacrylic acid. The preferred polymer electrolyte is the sodium salt of polyacrylic acid.

The optimum amount of polymeric additives will, of course, vary widely with the base polymeric material and the exact additives used, and the desired volume resistivity of the final mixture. However, as a general rule, additives at concentrations of about 10 ^"5 to about 10 ^"4 moles per gram of polymeric material have been found to produce useful results. When the additive is a salt, the range is 1:1 salt, such as tetrabutylammonium chloride, tetrabutylammonium hexafluorophosphate, and potassium acetate; if a 1:2 salt is used, such as sodium carbonate or potassium chloride, then each A lower concentration of salt on the order of 10 ^-6 moles per gram of polymeric material will suffice. The volume resistivity of polymeric materials generally changes in a predictable manner with additive concentration, so the final choice of how much additive should be added to achieve the desired volume resistivity can easily be determined experimentally.

Although small amounts of salt have been added to polymers as binders and laminating adhesives in prior art optoelectronic displays, such as as biocides to protect the polymer from biodegradation during long-term storage, this salt generally exhibits Its biocidal or similar functions are used up. In contrast, the additives used in the present invention are intended to be permanent components of the polymeric material since it is intended to permanently adjust its electrical conductivity. The optimal amount of additives used is generally substantially greater than the amount of salt used as biocides and the like.

Examples of fibers including light-transmissive conductors of the present invention are shown in Figures 1-6B. Specific reference is now made to Figure 1, which depicts a cross-sectional view of an optoelectronic fiber in accordance with a first embodiment. The fiber contains a central conductive core 10 in the form of fibers or leads. The central conductive fiber 10 preferably has a high aspect ratio, such as 10:1, such as 100:1, so that the fiber remains flexible after it has been coated with layers. For example, the length of the central conductive fiber may be greater than or equal to 100 times the fiber thickness. Because of this high aspect ratio, the fibers should be strong enough to withstand the weaving process. Also due to the high aspect ratio, the fiber conductivity is preferably high and is suitable as an electrode to switch the photoelectric medium applied to its surface. For example, any metal, metal alloy, conductive polymer, and fiber with sufficient electrical conductivity known in the art, or composites containing these materials, can be used in various embodiments of the present invention. Conductive materials that can be used to form the central conductive fiber include, but are not limited to, copper, tungsten, aluminum, nickel, stainless steel, gold, silver, carbon fiber, and combinations thereof. Alloys of the above conductive metals may also be added to the central conductive fiber. For example, a conductive metal can be electroplated onto the surface of the core fiber to form a conductive fiber.

As shown above, the thickness of the central conductive fiber is selected to provide a large enough surface area to facilitate coating with photoelectric media, but not so large that it would be difficult to use stiff fibers for fabric weaving. The greater thickness of the central conductive fiber also facilitates aggressive cleaning of the fibers to expose electrical connections such as leads to power supplies and/or controllers. Preferably, the thickness of the central conductive fiber is greater than or equal to about 20 microns and less than or equal to about 250 microns.

Various embodiments of the present invention can create inherently breathable and flexible fabrics by weaving photovoltaic threads. Optoelectronic fibers according to various embodiments of the present invention can be used on standard looms, and the manufacturing process used to make the fibers is easily scalable. Additionally, the lines can be independently addressed, and the optoelectronic media applied to each line can contain different formulations. As a result, fabrics made using the optoelectronic fibers disclosed herein can use a plurality of different fibers. For example, one group of fibers may include encapsulated electrophoretic media containing white and red pigments, a second group may include media containing white and green pigments, and a third group may include media containing white and blue pigments. The fabric can be woven in three sets of threads, allowing the final weaving configuration to combine any four colors in various switchable ratios and patterns, giving the fabric a broad spectrum of selectable colors. The electrophoretic medium is not limited to two pigments. The encapsulated electrophoretic medium may include three or more pigments and/or colored dispersion fluids, allowing for countless optical combinations within the fabric, such as the electrophoretic medium disclosed in US Pat. No. 9,921,451. By using bistable photoelectric media, only low power is required to switch materials, and the electronic control used to switch materials is detachable.

Referring again to Figure 1, the central conductive fiber 10 is preferably passivated by coating the fiber 10 with at least one dielectric layer 12a, 12b. The dielectric layers 12a, 12b are applied before and/or after the layer of optoelectronic medium 14 is applied. Passivating the fiber 10 leads with a dielectric layer prevents electrical short circuit failures that may occur when the optoelectronic medium 14 is overcoated with another layer of conductive material 16 . Gaps in the optoelectronic layer 14 may cause short circuit failure; therefore, adding additional layers of dielectric material may reduce the likelihood of this occurring.

The dielectric layers 12a, 12b may comprise materials including, but not limited to, polyurethane, or a 100% solids UV curable monomer such as an acrylate product such as CN3108 manufactured by Sartomer USA, LLC. The dielectric layers 12a, 12b may be applied to form an annular coating around the outer surface of the conductive fiber 10. The thickness of the annular coating is preferably as thin as possible without pinhole defects, so that the dielectric layer exhibits a resistance of, for example, 1e6 to 1e8 ohms/square. The dielectric material is preferably hydrophilic and preferably insoluble in water so that the dielectric layer is not dissolved or removed during application of the photovoltaic medium, which may be applied as an aqueous slurry.

As shown above, the optoelectronic fiber further includes a layer of optoelectronic medium 14 on the central conductive fiber 10 . The photoelectric medium is preferably a solid photoelectric material. Some optoelectronic materials are solid, meaning the material has a solid outer surface, although the material can, and often does, have internal spaces filled with liquid or gas. Thus, the term "solid state optoelectronic material" may include rotating dichromatic components, encapsulated electrophoretic media, and encapsulated liquid crystal media.

Rotating dichromatic element types of optoelectronics are disclosed, for example, in U.S. Patent Nos. 5,808,783, 5,777,782, 5,760,761, 6,054,071, 6,055,091, 6,097,531, 6,128,124, 6,137,467, and 6,147,791 (although this type of media is often referred to as "rotating duplex" color ball", but the term "Rotating two-color component" is more accurate and preferable because in some of the above-mentioned patents, the rotating component is not a sphere). This medium uses a large number of small bodies (usually spherical or cylindrical), which have two or more parts with different optical properties, and internal dipoles. The individuals are suspended in fluid-filled vacuoles within the matrix, which are filled with fluid allowing the individuals to rotate freely. The appearance of the material changes the portion of the individual viewed through the viewing surface as an electric field is applied to it, thus rotating the individual into different positions. This type of photoelectric medium is generally bistable.

The terms "bistable" and "bistable" are used herein in their conventional meaning in the art to mean optoelectronic materials having at least one first and second state with different optical properties such that in the borrowed After the limited-time addressing pulse drives the optoelectronic material to assume its first or second state, the state will continue to last for at least several times, for example, at least 4 times, the shortest addressing pulse time required to change the state of the optoelectronic material after the addressing pulse terminates. . US Patent No. 7,170,670 demonstrates that some particle-based electrophoretic materials that can have gray scales are stable not only in their extreme black and white states, but also in their intermediate gray states, and the same is true for some other types of optoelectronic media. This type of media is properly termed "multistable" rather than bistable, although for convenience the term "bistable" may be used here to cover both bistable and multistable media.

The term "grey state" is used here in its conventional sense in the field of imaging technology to indicate a state in the middle of two extreme optical states, and does not necessarily imply a black-to-white transition between these two extreme states. For example, many of the E Ink patents and published applications referenced below describe electrophoretic materials in which the extreme states are white and dark blue, so the intermediate "gray state" is actually light blue. In fact, as already mentioned, optical state changes may not be color changes at all. The terms "black" and "white" may be used below to represent two extreme optical states of materials, and it is understood that these generally include extreme optical states that are not strictly black and white, such as the white and dark blue states described above. The term "monochromatic" may be used herein to refer to a drive scheme in which the optoelectronic medium is driven only to its two extreme optical states with no intermediate gray state.

Another type of optoelectronic media uses electrochromic media, such as electrochromic media in the form of nanochromic films, which include an electrode formed at least in part from a semiconducting metal oxide, and a plurality of reversibly color-changing dyes attached to the electrode. Molecules; see, for example, O'Regan, B. et al., Nature 1991, 353 , 737; and Wood, D., Information Display, 18(3) , 24 (March 2002). See also Bach, U. et al., Adv. Mater., 2002, 14(11) , 845. This type of nanochromic film is also disclosed in, for example, U.S. Patent Nos. 6,301,038, 6,870,657, and 6,950,220. This type of medium is also generally bistable.

Another type of optoelectronic medium is the electrowetting display developed by Philips and described in Hayes, R.A. et al., "Video-Speed Electronic Paper Based on Electrowetting", Nature, 425, 383-385 (2003). As shown in US Patent No. 7,420,549, this electrowetting medium can be made bistable.

Type 1 optoelectronics are particle-based electrophoretic media, which have been the subject of intensive research and development for many years, in which a plurality of charged particles move through a fluid under the influence of an electric field. Compared with liquid crystal displays, electrophoretic media can have properties such as good brightness and contrast, wide viewing angles, bistable properties, and low power consumption.

As shown above, the electrophoretic medium requires fluid. In most state-of-the-art electrophoretic media, this fluid is a liquid, but electrophoretic media can be made using gaseous fluids; see, for example, "Electrical toner movement for electronic paper-like display" by Kitamura, T. et al., IDW Japan, 2001, Paper HCS1-1; and "Toner display using insulative particles charged triboelectrically" by Yamaguchi, Y. et al., IDW Japan, 2001, Paper AMD4-4. See also U.S. Patent Nos. 7,321,459 and 7,236,291.

Many patents and applications assigned to or in the name of the Massachusetts Institute of Technology (MIT) and E Ink Corporation, E Ink California, LLC, and related companies describe various electrophoretic and other optoelectronic media technologies for packaging. The encapsulated electrophoretic medium includes a plurality of small capsules, each of which itself includes an internal phase containing electrophoretically mobile particles in a fluid medium, and a capsule wall surrounding the internal phase. Typically, the capsule itself is held within a polymeric binder to form a coherent layer between the two electrodes. Technologies disclosed 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 methods; see, for example, U.S. Patent Nos. 6,922,276 and 7,411,719; (c) Films and subassemblies containing optoelectronic materials; see, for example, U.S. Patent Nos. 6,982,178 and 7,839,564; (d) Backsheets, adhesive layers, and other auxiliary layers and methods for displays; see, for example, U.S. Patent Nos. 7,116,318 and 7,535,624; (e) Color formation and color adjustment; see, for example, U.S. Patent Nos. 7,075,502 and 7,839,564; (f) Methods of driving displays; see, for example, U.S. Patent Nos. 7,012,600 and 7,453,445; and (g) Display applications; see, for example, U.S. Patent Nos. 7,312,784 and 8,009,348.

Many of the above-mentioned patents and applications believe that the wall surrounding the separated microcapsules in the encapsulated electrophoretic medium can be replaced by a continuous phase, thus creating a so-called polymer-dispersed electrophoretic display, in which the electrophoretic medium contains a plurality of separated droplets of electrophoretic fluids, and polymers. The material is a continuous phase, and the separated droplets of electrophoretic fluid within such a polymer-dispersed electrophoretic display may be considered capsules or microcapsules, even though there is no separate capsule film binding each individual droplet; see, for example, US Pat. No. 6,866,760, supra. For the purposes of this invention, the polymer-dispersed electrophoretic medium is therefore considered secondary to the encapsulated electrophoretic medium.

Encapsulated electrophoretic media generally do not suffer from clustering and sedimentation failures and offer further advantages, such as the ability to print or coat the media on a wide variety of flexible and rigid substrates. (The word "printing" is intended to include 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 tandem coating, Curtain coating; roller coating, such as doctor roller coating, front and back roller coating; gravure coating; dip coating; spray coating; curved coating; spin coating; brush coating ; Air knife coating; screen printing; electrostatic printing; thermal printing; inkjet printing; electrophoretic deposition (see U.S. Patent No. 7,339,715); and other similar technologies.) In addition, because the medium can be printed (using various methods), applications utilizing this medium can be inexpensively manufactured.

Optoelectronic media preferably used in various embodiments of the present invention are provided in the form of microencapsulated electrophoretic media. For example, referring again to FIG. 1 , a layer of microencapsulated electrophoretic media 14 may be coated, for example, as a ring-shaped coating around central conductive fiber 10 . The thickness of the annular coating can be greater than or equal to about 10 microns, preferably about 15 microns, more preferably about 20 microns, and less than or equal to about 250 microns, preferably about 100 microns, and more preferably about 75 microns. , and optimally is about 50 microns. As shown above, layers of dielectric material 12a, 12b may be applied under and/or over electrophoretic medium layer 14. Microencapsulated coatings may be provided, for example, in the form of aqueous coating slurry formulations containing a dispersion of microencapsulated electrophoretic particles and a binder. The adhesive material may include, but is not limited to, aqueous polymeric emulsion dispersions or water-soluble polymer solutions (such as polyvinyl alcohol (such as Kuraray Poval® CM-318), isinglass, and alginate). The slurry formulation may further include one or more additives, such as hydroxypropyl methylcellulose, surfactants (eg, Triton X-100), and co-solvents (eg, butanol).

After application of the slurry formulation, electrophoretic media layer 14 may be dried prior to application of light-transmissive conductor 16 . The light-transmissive conductor 16 may be, for example, an annular coating surrounding the optoelectronic layer 14 . As mentioned above, the light-transmitting conductor 16 includes a light-transmitting polymer with a volume resistivity between 1x10 ¹⁰ ohm-cm and 1x10 ⁴ ohm-cm, and a directional conductive element with an aspect ratio greater than 10:1. The term "light-transmissive" is used herein to mean that a layer so designed transmits light sufficient to allow a viewer to see through the layer to observe a change in the optical state of the optoelectronic medium, typically viewed through a conductive layer; the optoelectronic medium exhibits reflectivity at non-visible wavelengths Changing circumstances, the term "transmission" should of course be read to mean the transmission of relevant non-visible light wavelengths.

Referring now to Figures 2 and 3, an optoelectronic fiber 20 according to another embodiment of the present invention is provided. The optoelectronic fiber 20 includes many of the same layers as the fiber produced in accordance with the first embodiment described above. For example, the optoelectronic fiber 20 includes a similar core including conductive fibers 30 , and a similar optoelectronic material layer 32 can be coated on the outer surface of the conductive fibers 30 . The aforementioned dielectric material layer is optional in the second embodiment.

The optoelectronic fiber 20 differs from the first embodiment in that the light-transmissive conductor includes conductive leads 36 disposed in a light-transmissive polymer material layer 34 with a volume resistivity between 1x10 ¹⁰ ohm-cm and 1x10 ⁴ ohm-cm. The conductive leads 36 may be wound in a coil or spiral form, such as around an optical fiber core, and a layer of light-transmissive polymeric material 34 may be coated on the conductive leads, such as by dip coating, spraying, slot coating, or the like. In some embodiments, multiple leads may be used. It should be noted that the leads do not have to be straight to get the claimed aspect ratio, such as 10:1 or above.

The layer 34 of light-transmissive polymeric material may be provided as an annular coating having a thickness of about 5 microns to about 200 microns, preferably to about 50 microns, preferably measured from the conductive leads to the optoelectronic medium. The light-transmissive polymeric material 34 may include the doped polymeric materials discussed previously. The composition and thickness of the light-transmissive polymeric material 34 are selected such that the light-transmissive polymeric material 34 is light-transmissive and the individual conductive lead packages 36 are separated without substantially hiding the underlying optoelectronic media, while electrical drive signals can still traverse between the leads. all areas. This phenomenon is also known as "blooming," whereby the area over which the photovoltaic layer changes its optical state in response to voltage changes is greater than the area of the electrode, in this case the area where the conductive leads contact the light-transmitting polymeric material. The distance between the coil-shaped outer conductive lead packages may be less than 5 mm, more preferably about 1 mm or less, and most preferably about 500 microns or less.

Doped polymeric materials that can be used in semiconductive polymeric materials may include, but are not limited to, dopants such as tetrabutylammonium hexafluorophosphate, 1-butyl-3-methylimidazolium hexafluorophosphate, polyvinyl alcohol , ionic modified polyvinyl alcohol, gelatin, polyvinylpyrrolidone, and combinations thereof) aliphatic or aromatic polyurethane emulsions, polyacrylates, and poly(meth)acrylates. Polymeric blends containing aromatic isocyanates are less favorable. Examples of formulations that may be included in semiconductive polymeric materials are disclosed in U.S. Patent Application Publication No. 2017/0088758, and U.S. Patent Nos. 7,012,735, 7,173,752, and 9,777,201.

The conductive leads applied to the surface of the semiconductive polymeric material are preferably more pliable and less thick than the central core lead so that the outer conductive leads can be wrapped repeatedly around the outer surface of the semiconductive polymeric material. The outer conductive lead preferably has a thickness of about 10 to about 100 microns and is made of a highly conductive material, such as metal. Therefore, like the central conductive core of an optoelectronic fiber, the outer conductive leads can be made of metal, such as copper or tungsten.

In the third embodiment of the present invention depicted in FIGS. 4 and 5 , the optoelectronic fiber 40 includes the same features as the second embodiment described above. Optoelectronic fiber 40 may include a central conductive core 50 , a layer of optoelectronic medium 54 applied to the outer surface of core 50 , and a layer of light-transmissive conductor 56 applied to the outer surface of optoelectronic medium 54 .

The third embodiment is different from the second embodiment in that a plurality of outer conductive leads 52 are embedded in the outer surface of the light-transmitting conductor layer 56 . Rather than wrapping the outer surface, the outer conductive leads 52 have been applied so that they are substantially parallel to the inner conductive core 50 . The outer conductive leads may be added with multiple spools unwound parallel to the fibers. The fiber can be advanced through the spool, and the spool unwinds the leader under slight tension as the fiber advances. The reel does not have to rotate around the fiber.

All various embodiments of the present invention may further include an outer light-transmissive protective layer, such as layer 38 in Figure 3 or layer 58 in Figure 5. The protective material layer can be designed to serve as a mechanical and environmental protection layer for the underlying material. The protective material may include polymeric materials such as polyvinyl alcohol, cross-linked gelatin, acrylics, urethane acrylate copolymers, and blends thereof. To provide a more water-resistant protective layer, the polymeric material may include a 100 percent solids radiation-cured hardcoat material, such as DCU2002 solvent-based hardcoat material manufactured by PPG Industries Inc., which is a solvent-based high solids polyamine. Carbamate automotive clear hard coat material.

Coating layers in various embodiments of the present invention, such as layers of dielectric materials, optoelectronic media, external conductive materials, semiconductive polymeric materials, and protective materials, can be applied via various printing methods, as shown above , which includes but is not limited to dip coating, electrodeposition, powder coating, spray coating, or extrusion.

To switch the optical state of the optoelectronic fiber's optoelectronic medium, a voltage is applied between the central conductive core and the outer conductor of the fiber. If the optoelectronic medium contains an electrophoretic medium, the applied electric field causes the electrophoretic particles within the encapsulated dispersion to move toward or away from the central conductive core. For example, FIGS. 6A and 6B illustrate the optoelectronic fiber 20 according to the second specific embodiment of the present invention in two different optical states. The photoelectric layer 32 may be filled with an electrophoretic dispersion containing, for example, a white fluid and positively charged black particles. As shown in FIG. 6A , when a voltage is applied to the central conductive core fiber 30 and the outer conductive lead 36 so that the central conductive core fiber 30 is positive relative to the outer conductive lead 36 , the positively charged black particles are driven away from the center. The conductive core fiber 30 is oriented towards the outer circumferential viewing side of the fiber and causes a dark optical state of the fiber 20 . When the polarity is reversed, as depicted in FIG. 6B , the charged black particles are driven toward the central conductive core fiber 30 such that the black particles are obscured by the white dispersion fluid, resulting in a white optical state of the fiber 30 .

Although light-transmitting conductors with directional conductivity can be used to make long cylindrical objects, such as fibers, the light-transmitting conductors can also be used to form various structures with high aspect ratios, such as ribbons, rectangles, and strips.

Various configurations of light-transmissive conductors 70 are shown in Figures 7A-7D. In a simple embodiment, as shown in FIG. 7A , the light-transmitting conductor 70 includes a light-transmitting polymer 72 with a volume resistivity between 1x10 ¹⁰ ohm-cm and 1x10 ⁴ ohm-cm, and a plurality of transverse light-transmitting strips. The length of conductor 70 is the lead 74 . The leads can be silver, copper, aluminum, nickel, zinc, gold, steel, or any combination thereof. Because the longitudinal resistivity is dominated by the conductivity of the lead, the total conductivity along the length of the light-transmitting conductor is less than 1x10 ^"3 ohm-cm, for example less than 1x10 ^"6 ohm-cm. However, the lateral conductivity is dominated by the volume resistivity of the light-transmitting polymer, so the lateral conductivity is also generally on the order of 1x10 ¹⁰ ohm-cm to 1x10 ⁴ ohm-cm. Depending on doping levels, etc., the volume resistivity of light-transmitting polymers can be close to 1x10 ⁷ ohm-cm to 1x10 ⁵ ohm-cm, which experimentally seems to be sufficient to minimize self-erasing in electrophoretic displays, as shown in the figure below 9 discussed.

An alternative configuration may include an elongated polygonal structure 75, such as a hexagon, as shown in Figure 7B, provided that the elongated polygonal structure has a selected conductivity direction. The proportions of the long polygonal structure are not limited to large-format devices, and the small hole lead structure can be adapted to be as small as individual atomic sheets, such as graphene. The polygonal structure can again include silver, copper, aluminum, nickel, zinc, gold, steel, or any combination thereof. In some embodiments, elongated polygonal structure 75 may comprise multiple types of materials, with more conductive materials running along the length of light-transmissive conductor 70 and different less conductive materials running along the width. Grid 76 can act as a directional conductor in a similar manner by selecting materials with different conductivities for different portions of grid 76 . The polygonal structure 75 and the grid 76 provide higher structural stability in the light-transmitting conductor 70 so that it can be bent in multiple directions.

In yet another specific embodiment, as shown in FIG. 7D , the directional conductive element can be composed of conductive sheets, single wires, silver, whiskers, nanowires, nanotubes, or combinations thereof, where the accompanying The conductors are oriented to achieve an aspect ratio greater than 10:1. For example, the light-transmissive polymer 72 can be loaded with silver whiskers 77, and the mixture is mechanically actuated to cause the silver whiskers 77 to be approximately aligned along the axis of the light-transmissive conductor 70, thereby creating directionality in conductivity. After the conductor 77 has been oriented, the light-transmissive polymer 72 can be cured or cross-linked to lock the conductor in its preferred orientation. The conductor may include carbon nanotubes, silver, tungsten, iron, copper, nanoparticles, metal mesh, or graphene. The method of manufacturing the light-transmissive conductor 70 of Figure 7D is shown in Figure 8, which includes providing a light-transmissive polymer 72 at step 62, disposing the conductor 77 in the light-transmissive polymer 72 at step 64, and placing the conductor 77 outside the conductor 77 at step 66. Orientation is stimulated, and the light-transmissive polymer 72 is optionally cured at step 68 . Other methods of aligning component conductors may include applying electrical or magnetic fields to stimulate alignment. Magnetic fields are particularly useful for aligning magnetic or paramagnetic materials, such as iron, tungsten and aluminum. In some cases composite materials, such as silver wire spun with iron, may be used, making it easier to align conductor 77. In some embodiments, the larger conductor 77 may be coated with iron powder, for example, to facilitate alignment in a better direction with a magnetic field, for example. The light-transmissive polymer 72 may be cured by heat or pressure, or the light-transmissive polymer 72 may include a cross-linking agent that is activated with heat or UV light, for example.

The light-transmitting conductor of the present invention can be used as an upper electrode in an optoelectronic display, as shown in Figure 9. Figure 9 is a schematic cross-section through a basic front plate laminate 80 of an optoelectronic display having a light-transmissive conductive layer of the present invention. Generally speaking, the light-transmitting conductive layer 84 is supported by a light-transmitting substrate 82, which is preferably flexible. The substrate can be manually wound around a cylinder with a diameter of 10 inches (254 mm) without permanent deformation. Substrate 82 is generally a polymeric film and typically has a thickness in the range of about 1 to about 25 mils (25 to 634 microns), preferably in the range of about 2 to about 10 mils (51 to 254 microns). The substrate 82 forms the viewing surface of the final display and may have one or more additional layers, such as a protective layer to absorb ultraviolet radiation, a barrier layer to prevent moisture ingress, or an anti-reflective coating.

The light-transmissive conductive layer 84 includes a light-transmissive polymer with a volume resistivity between 1x10 ¹⁰ ohm-cm and 1x10 ⁴ ohm-cm, and a directional conductive element with an aspect ratio greater than 10:1, as discussed above. A layer of optoelectronic medium 86 electrically contacts the light-transmissive conductive layer 84 . However, in some embodiments, a layer of optically clear adhesive (not shown) is also present between the light-transmissive conductive layer 84 and a layer of optoelectronic medium 86 . The photoelectric medium 86 shown in Figure 9 is an electrophoretic medium encapsulated by oppositely charged dual particles. It has a plurality of microcapsules each including a capsule wall 88. It contains a hydrocarbon-based liquid 90 in which negatively charged white particles 92 and positively charged particles are suspended. Electric black particles94. The microcapsules are retained within adhesive 95. When an electric field is applied across photovoltaic layer 86, white particles 92 move to the positive electrode and black particles 94 move to the negative electrode such that photovoltaic layer 86 views the electric field across photovoltaic layer 84 as positive relative to the backplane anywhere in the final display. or negative, appears white or black to a viewer viewing the display through substrate 82.

The front plate laminate 80 shown in FIG. 9 further includes a layer of lamination adhesive 96 adjacent to the photoelectric layer 86 and a release sheet 98 covering the adhesive layer 96. The release layer 98 is peeled from the adhesive layer 96 and the adhesive layer is laminated to the backplane to form the final optoelectronic display. The two-phase conductive layer of the present invention can be the front electrode of the photoelectric display, which is the electrode located on the side closest to the viewing surface. In an optoelectronic display that is completely transparent or has two viewing surfaces, the two-phase conductive layers of the present invention can be both front and back electrodes. The backing plate can be, for example, a single electrode material such as a graphite electrode, a metal foil or a conductive film (such as PET-ITO). The backplane can be a segmented display, a passive matrix display, or an active matrix display. In some cases, the backplane includes an active matrix of thin film transistors to control voltages on a plurality of pixel electrodes.

Although 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. Many variations, modifications and substitutions may be made by those skilled in the art without departing from the spirit of the invention. It is therefore intended that the appended claims cover all such changes within the spirit and scope of the invention.

The contents of all above-mentioned patents and applications are hereby incorporated by reference in their entirety.

10: Central conductive fiber

12a: Dielectric layer

12b: Dielectric layer

14: Optoelectronic medium and electrophoretic medium layer

16: Conductive materials, light-transmitting conductors

20: Optoelectronic fiber

30: Conductive fiber

32: Optoelectronic material layer, optoelectronic medium layer

34: Translucent polymeric material

36: Conductive lead

38:Outer transparent protective layer

40: Optoelectronic fiber

50: Central conductive core

52:Outer conductive lead

54: Optoelectronic media

56:Light-transmitting conductor

58:Outer transparent protective layer

62,64,66,68: Steps 70: Translucent conductor 72:Light-transmitting polymer 74:lead 75: Long polygonal structure 76:Grid 77: Conductor, silver whiskers 80:Basic front plate laminate 82: Translucent substrate 84:Light-transmitting conductive layer 86: Optoelectronic medium (layer) 88:cyst wall 90: Hydrocarbon liquid 92: Negatively charged white particles 94: Positively charged black particles 95: Adhesive 96:Laminated adhesive 98: Breakaway film

The drawings are only examples to describe one or more implementations according to the present invention, and are not limiting. Figure not to scale. In the drawings, the same element symbols refer to the same or similar elements.

Figure 1 is a cross-sectional view of an optoelectronic fiber according to a first specific embodiment of the present invention.

Figure 2 is a top perspective view of an optoelectronic fiber according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view along axis I-I of the second embodiment depicted in FIG. 2 .

Figure 4 is a top perspective view of an optoelectronic fiber according to a third embodiment of the present invention.

FIG. 5 is a cross-sectional view along axis II-II of the third embodiment depicted in FIG. 5 .

FIG. 6A is a cross-sectional view of the second embodiment depicted in FIG. 2 in a first optical state.

FIG. 6B is a cross-sectional view of the second embodiment depicted in FIG. 2 in a second optical state.

Figure 7A shows an exemplary light-transmissive conductor with directional conductivity.

Figure 7B shows an exemplary light-transmissive conductor with directional conductivity.

Figure 7C shows an exemplary light-transmissive conductor with directional conductivity.

Figure 7D shows an exemplary light-transmissive conductor with directional conductivity.

Figure 8 shows a flow chart for manufacturing a light-transmissive conductor with directional conductivity.

9 is a schematic cross-section through a basic front plate laminate (80) of an optoelectronic display using a light-transmitting conductor with directional conductivity as an upper electrode.

10: Central conductive fiber

12a: Dielectric layer

12b: Dielectric layer

14: Optoelectronic medium and electrophoretic medium layer

16: Conductive materials, light-transmitting conductors

Claims (22)

A light-transmitting conductor, which includes: a light-transmitting polymer with a volume resistivity between less than 1x10 ⁷ ohm-cm and 1x10 ⁵ ohm-cm, and is doped with a conductive additive; and a directional conductive element with a vertical and horizontal conductive element. The ratio is greater than 10:1 (length:width). A light-transmissive conductor comprising: a light-transmissive polymer having a volume resistivity between less than 1x10 ⁷ ohm-cm and 1x10 ⁵ ohm-cm; and a directional conductive element having an aspect ratio greater than 10:1 (length:width) ), and the directional conductive element is a lead or conductive fiber. A light-transmissive conductor comprising: a light-transmissive polymer having a volume resistivity between less than 1x10 ⁷ ohm-cm and 1x10 ⁵ ohm-cm; and a directional conductive element having an aspect ratio greater than 10:1 (length:width) ), and the oriented conductive element includes a plurality of conductive sheets, single wires, silver, whiskers, nanowires, or nanotubes oriented so that the aspect ratio is greater than 10:1. The light-transmitting conductor according to any one of claims 1 to 3, wherein the light-transmitting polymer is flexible. The light-transmitting conductor of claim 1, wherein the dopant is a salt, a polymer electrolyte (polyelectrolyte), a polymer electrolyte (polymer electrolyte), or a solid electrolyte. The light-transmitting conductor of claim 3, wherein the directional conductive element includes carbon nanotubes, silver, tungsten, iron, copper, nanoparticles, metal mesh, or graphene. The light-transmitting conductor according to any one of claims 1 to 3, wherein the aspect ratio of the directional conductive element is greater than 100:1. The light-transmitting conductor according to any one of claims 1 to 3, wherein the visible light transmittance of the light-transmitting polymer is greater than 70%. A film with a thickness less than 500 microns, comprising the light-transmitting conductor according to any one of claims 1 to 3. An optoelectronic display comprising: a front electrode comprising a layer of light-transmitting conductor, the light-transmitting conductor comprising: a light-transmitting polymer having a volume resistivity between less than 1x10 ⁷ ohm-cm and 1x10 ⁵ ohm-cm, and being doped conductive additives, and directional conductive elements with an aspect ratio greater than 10:1 (length:width); a back electrode; a photoelectric layer disposed between the front electrode and the back electrode; and a voltage source, It is connected to the front electrode and the back electrode. An optoelectronic display comprising: a front electrode comprising a layer of light-transmissive conductor, the light-transmissive conductor comprising: a light-transmissive polymer having a volume resistivity between less than 1x10 ⁷ ohm-cm and 1x10 ⁵ ohm-cm, and an orientation A conductive element whose aspect ratio is greater than 10:1 (length:width) and is a lead or conductive fiber; a back electrode; a photoelectric layer disposed between the front electrode and the back electrode; and a voltage source connected to the front electrode and the back electrode. An optoelectronic display comprising: a front electrode comprising a layer of light-transmissive conductor, the light-transmissive conductor comprising: a light-transmissive polymer having a volume resistivity between less than 1x10 ⁷ ohm-cm and 1x10 ⁵ ohm-cm, and an orientation Conductive components having an aspect ratio greater than 10:1 (length:width) and containing a plurality of conductive sheets, single wires, silver, whiskers, nanoleads, or nanotubes oriented such that the aspect ratio is greater than 10:1; back electrode; photoelectric medium layer, which is arranged between the front electrode and the back electrode; and a voltage source, which is connected to the front electrode and the back electrode. The optoelectronic display as claimed in any one of claims 10 to 12, wherein the optoelectronic medium layer contains charged pigment particles in a solvent. The photoelectric display of claim 13, wherein the charged pigment particles and solvent are encapsulated in microcapsules or sealed in microcells. Such as the optoelectronic display of claim 13, wherein the charged pigment particles include two groups of charged pigment particles, each group having different charge polarities and different optical characteristics. The optoelectronic display of any one of claims 10 to 12, further comprising an optically transparent adhesive between the front electrode and the optoelectronic medium layer. A method of manufacturing a light-transmitting conductor, comprising: providing a light-transmitting polymer with a volume resistivity between less than 1x10 ⁷ ohm-cm and 1x10 ⁵ ohm-cm, the light-transmitting polymer being doped with a conductive additive; and Oriented conductive elements with an aspect ratio greater than 10:1 (length:width) are disposed in the light-transmitting polymer. A method of manufacturing a light-transmissive conductor, comprising: providing a light-transmissive polymer with a volume resistivity between less than 1x10 ⁷ ohm-cm and 1x10 ⁵ ohm-cm; and converting an aspect ratio greater than 10:1 (length:width) A directional conductive element is configured in the light-transmitting polymer, wherein the directional conductive element is a lead or a conductive fiber. A method of manufacturing a light-transmissive conductor, comprising: providing a light-transmissive polymer with a volume resistivity between less than 1x10 ⁷ ohm-cm and 1x10 ⁵ ohm-cm; and converting an aspect ratio greater than 10:1 (length:width) A directional conductive element is disposed in the light-transmitting polymer, wherein the directional conductive element includes a plurality of conductive flakes, single wires, silver, whiskers, nanowires, or nanotubes oriented so that the aspect ratio Greater than 10:1. The method of any one of claims 17 to 19, further comprising: arranging a plurality of the directional conductive elements in the light-transmitting polymer; orienting a plurality of the directional conductive elements using external stimulation; and orienting the plurality of directional conductive elements using external stimulation; The light-transmitting polymer cures. The method of claim 20, wherein the external stimulus is a magnetic field, an electric field, light, or mechanical actuation. The method of any one of claims 17 to 19, wherein the conductivity of the light-transmissive conductor in a direction orienting the plurality of directional conductive elements is less than 1x10 ^-3 ohm-cm.