CN114127628A - Electrophoretic display - Google Patents

Abstract

An electrophoretic display system includes a first electrode disposed on a substrate, and a three-dimensional (3D) carbon-based structure configured to guide migration of charged electrophoretic ink particles dispersed therein, the charged electrophoretic ink particles configured to respond to application of a voltage to the first electrode. The 3D carbon-based structure includes: a plurality of 3D aggregates defined by the morphology of graphene nanoplatelets orthogonally fused together and crosslinked by a polymer; and a plurality of channels interspersed throughout the 3D carbon-based structure defined by the morphology. The plurality of channels includes a plurality of inter-particle pathways and a plurality of intra-particle pathways. Each inter-particle via may have a smaller size than each inter-particle via. A second electrode is disposed on the 3D carbon-based structure. Each 3D aggregate may include any one or more of graphene, carbon nano-onions, carbon nano-sheets, or carbon nanotubes.

Description

Electrophoretic display

RELATED APPLICATIONS

This application claims priority to us provisional patent application 62/866,464 entitled "electrophosphorotic Display" filed on day 6, month 25 of 2019, and is a continuation-in-part application of us patent application 16/706,542 entitled "Resonant Gas Sensor" filed on day 6, 12, month 6 of 2019, which claims priority to us provisional patent application 62/815,927 entitled "Resonant Gas Sensor" filed on day 8, 3, month 3 of 2019 and is a continuation-in-part application of us patent application 16/239,423 entitled "Resonant Gas Sensor" filed on day 3, 1 month 3 of 2019, which claims priority to us provisional patent application 62/613,716 entitled "vollates Sensor" filed on day 4, 1 month 1 of 2018; and this application is a continuation-in-part application and claims priority from U.S. patent application 16/282,895 entitled "Antenna with Frequency-Selective Elements" filed on 22.2.2019, a continuation application of U.S. patent application 15/944,482 entitled "Antenna with Frequency-Selective Elements" filed on 3.4.2018, a priority from U.S. provisional patent application 62/508,295 entitled "Carbon-based Antenna" filed on 18.5.2017, a priority from U.S. provisional patent application 62/482,806 entitled "Dynamic Energy Harvesting Power" filed on 7.4.7.2017, and a priority from U.S. provisional patent application 62/481,821 entitled "Dynamic Energy Harvesting Power" filed on 5.4.2017; all of these patents are hereby incorporated by reference in their entirety for all purposes.

Technical Field

The present disclosure relates generally to an electrophoretic display, and more particularly to an electrophoretic display device that includes carbon particles crosslinked to each other by a polymer and that when activated simulates the appearance of conventional ink on paper.

Background

Electrophoretic displays (EPDs), also known as electronic paper, provide a low-power alternative to conventional flat panel displays and have therefore been widely used in a variety of consumer products, including electronic reading devices, digital notebooks, shelf labels, signs, and simple displays suitable for packaging or for use as digital labels. Unlike conventional backlit flat panel displays that emit light, EPDs reflect light like conventional paper. This can make it more readable and provide a wider viewing angle than most lighted displays. EPDs typically operate by using charged pigment particles held between a front substrate and a back substrate. When a voltage is applied across the two plates, the particles migrate to the plate with a charge opposite to the charge on the particles. Current EPD devices are limited in resolution and performance due to the use of conventional materials. It is desirable to implant highly structured and surface functionalized carbon particles to enhance EPD resolution, reduce power consumption and extend service life, while reducing production costs.

Disclosure of Invention

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Moreover, the systems, methods, and devices of the present disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

One innovative aspect of the subject matter described in the present disclosure can be realized as a three-dimensional (3D) carbon-based structure configured to guide migration of charged electrophoretic ink particles dispersed therein, the charged electrophoretic ink particles configured to respond to application of a voltage to a first electrode. The 3D carbon-based structure may include a plurality of 3D aggregates defined by morphologies of graphene nanoplatelets orthogonally fused together and crosslinked by a polymer and a plurality of channels defined by the morphologies dispersed throughout the 3D carbon-based structure. The plurality of channels may include a plurality of inter-particle pathways and a plurality of intra-particle pathways. Each inter-particle via may have a smaller size than each inter-particle via. A second electrode may be disposed on the 3D carbon-based structure.

In some implementations, the electrophoretic display system can include a plurality of recesses formed in any one or more of the plurality of 3D aggregates or the plurality of channels. Any one or more of the interparticle passageways can have an average radial dimension of no greater than about 10 μm. Any one or more of the intra-particle passageways can have an average radial dimension greater than about 200 nm.

In some implementations, each 3D aggregate further includes any one or more of graphene, carbon nano-onions, carbon nano-sheets, or carbon nanotubes. The polymer may comprise any one or more of cellulose, cellulose acetate butyrate, styrene butadiene, polyurethane, polyether-polyurethane, acrylate, epoxy or vinyl.

Another innovative aspect of the subject matter described in this disclosure can be implemented as a method of making an electrophoretic display structure. The method can include self-nucleating a 3D open porous structure defined by a plurality of 3D carbon-based aggregates from a carbon vapor-containing stream; functionalizing one or more exposed surfaces of the 3D open porous structure with a nucleophilic moiety; and cross-linking the plurality of 3D carbon-based aggregates in the 3D open porous structure. Crosslinking may include converting nucleophilic moieties; and defining porosity in the 3D open porous structure.

In some implementations, the self-nucleation of the 3D open porous structure may further include defining a porosity with an average pore size greater than about 200 nm. The self-nucleation of the 3D open porous structure may include forming a plurality of passages defined by a plurality of 3D carbon-based aggregates therein. The plurality of passageways may be configured to direct a plurality of charged movable titania particles to a charged electrode disposed on an electrophoretic display structure. Any one or more of the plurality of charged movable titania particles may be configured to be non-reactively dragged into or out of the 3D open porous structure.

Another innovative aspect of the subject matter described in the present disclosure can be realized as a display device comprising a pair of electrodes disposed on a substrate and a three-dimensional (3D) carbon-based structure disposed between the pair of electrodes. The 3D carbon-based structure may be configured to direct migration of a plurality of charged electrophoretic ink particles dispersed therein based on a voltage difference applied to any one or more of the pair of electrodes. The 3D carbon-based structure may include: a plurality of 3D aggregates defined by the morphology of graphene nanoplatelets orthogonally fused together and crosslinked by a polymer; and a plurality of channels interspersed throughout the 3D carbon-based structure defined by the morphology. The plurality of channels may include a plurality of inter-particle pathways and a plurality of intra-particle pathways. Each inter-particle via may have a smaller size than each inter-particle via.

In some implementations, the 3D carbon-based structure may not rely on any one or more of microcups or microcapsules. The plurality of charged electrophoretic ink particles may comprise a plurality of negatively charged movable titanium dioxide particles. The negatively charged mobile titanium dioxide particles may exhibit a substantially white color. Negatively charged movable titanium dioxide particles exhibiting a substantially white color may be configured to be attracted to either one of the pair of electrodes when the electrode is positively charged; alternatively, when either one of the pair of electrodes is negatively charged, it is repelled away from the electrode.

In some implementations, the 3D carbon-based structure can be configured to be in a non-conductive state. The display device may include an antenna configured to provide power to the display device. The display device may include a contrast layer between the 3D carbon-based structure and any one or more of the pair of electrodes. The contrast layer may be a first color. The plurality of charged electrophoretic ink particles may be a second color different from the first color. The 3D carbon-based structure is defined by a polydispersity index of less than about 0.5.

The details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims. It should be noted that the relative dimensions of the following figures may not be drawn to scale.

Drawings

Implementations of the subject matter disclosed herein are illustrated by way of example and are not intended to be limited by the figures of the accompanying drawings. Like numbers refer to like elements throughout the drawings and description. It should be noted that the relative dimensions of the following figures may not be drawn to scale.

Fig. 1A shows a side cross-sectional schematic view 110A of an exemplary conventional EPD device 100A, according to some implementations.

Fig. 1B illustrates a conventional microcapsule-type electrophoretic display according to some implementations.

Fig. 1C shows a conventional PMEPD100C using microcup technology according to some implementations.

Fig. 1D illustrates a schematic cross-sectional view of an EPD device including a carbon-based structure, according to some implementations.

Fig. 1E illustrates an exemplary EPD device including a carbon-containing structure, according to some implementations.

Fig. 2 shows a schematic diagram illustrating the structure of an electrophoretic display, such as that shown in fig. 1, according to some implementations.

Fig. 3A-3B illustrate scanning electron microscope images of a structure (such as that shown in fig. 2) according to some implementations.

Fig. 4A-4B are schematic diagrams representing methods for fabricating a structure (such as shown in fig. 2) of an electrophoretic visual display (such as shown in fig. 1) according to some implementations.

Fig. 5 illustrates a cross-sectional view of an exemplary electrophoretic visual display, according to some implementations.

Fig. 6 illustrates a cross-sectional view of an exemplary electrophoretic visual display, according to some implementations.

Fig. 7A illustrates a schematic diagram representing a method of preparing a carbon ink for an electrophoretic visual display, according to some implementations.

Fig. 7B illustrates a schematic diagram representing another method of preparing a carbon ink for an electrophoretic visual display, according to some implementations.

Fig. 8 illustrates a cross-sectional schematic view of an exemplary display configuration for an electrophoretic visual display, according to some implementations.

Fig. 9 illustrates a cross-sectional schematic view of an exemplary display configuration for an electrophoretic visual display, according to some implementations.

Fig. 10 illustrates a cross-sectional schematic view of an exemplary display configuration for an electrophoretic visual display, according to some implementations.

Fig. 11 illustrates a cross-sectional schematic view of an exemplary display configuration for an electrophoretic visual display, according to some implementations.

Fig. 12 illustrates an image of an exemplary electrophoretic display unit according to some implementations.

Fig. 13 illustrates an image of an exemplary electrophoretic display unit according to some implementations.

Fig. 14 illustrates an image of an exemplary electrophoretic display unit according to some implementations.

Fig. 15A illustrates a schematic cross-sectional view of a multilayer exemplary electrophoretic display according to some implementations.

Fig. 15B illustrates a list of features associated with a multi-layer electrophoretic display, according to some implementations.

Fig. 16A illustrates an exemplary implementation of a multi-layer electrophoretic display according to some implementations.

Fig. 16B illustrates an exemplary implementation in which two multilayer substrates include different sets of components, according to some implementations.

Detailed Description

Introduction to the design reside in

Various implementations of the subject matter disclosed herein relate generally to systems and methods of manufacturing electrophoretic displays (referred to herein as "EPDs" and colloquially as "electronic paper"). Electronic paper (electronic paper/e-paper), and sometimes electronic ink, and electrophoretic displays are display devices (or components or display devices) that substantially simulate the appearance of conventional ("normal") wet ink used on paper. However, unlike conventional backlit flat panel displays that emit light (referring to modern flat panel televisions and computer monitor displays), electronic paper displays reflect emitted light onto them, similar to conventional paper. This may make EPDs relatively more natural to the eye and more comfortable to read in well-lit environments (such as outdoors on a sunny day, or in an office meeting room), while also providing a wider viewing angle than most conventional or currently available lighted displays. Notably, contrast ratios available in EPDs have reached levels similar to traditional print media (including newspapers). Thus, manufacturers can now benchmark EPD performance generally based on whether they can read in direct sunlight without producing images that appear faded (meaning that become visually unclear or indistinguishable due to a lack of sufficient contrast between bright and dark surfaces in the presence of significant external illumination).

Some EPD technologies can hold static text and images indefinitely without power, thus providing a useful low-cost alternative to traditional digital displays for certain unwanted application areas such as signage produced in grocery stores or disposable labels on goods and packaging. Flexible electronic paper may be configured to use plastic substrate materials and plastic electronics to provide structural rigidity in their respective display backplanes, while the lack of illumination may result in limited power consumption that translates into low operating costs. The applications of EPDs are numerous and may include electronic shelf labels and digital signage, schedules for airports, buses, regional railroads and subway (train) stations, ride sharing service pickup locations, electronic billboards (such as at stadiums), smart phone displays and portable electronic readers ("e-readers"), any one or more of the digital versions of books and magazines that are conventionally available in printed media form can be displayed with similar (or better) visual sensitivity and accuracy. Given that advances in electronic devices and cloud-based computing have significantly increased the amount of data that can be processed and exchanged daily in various economic sectors, from higher education to corporate finance, the ability to visually present up-to-date information to users has become increasingly important.

Notably, detailed display of textual and graphical information is important for internet of things ("IoT") systems, which refer to systems of interrelated computing devices, machinery, and digital machines that have identifiers and the ability to transmit data over a network without human-to-human or human-to-computer interaction, where low cost and power requirements pose significant challenges to their widespread deployment and use. Modern display technologies, including Organic Light Emitting Diode (OLED) technologies, provide bright, detailed and high resolution displays (with the full ability to accurately reproduce true black representations), but these rich graphics often require high operating costs, as reflected by continued power consumption, and may not be particularly suitable for integration with self-powered or other alternative energy harvesting solutions. For many IoT applications, including electronic shelf or packaging tags, it is more desirable to provide the basic necessary information at low power than to provide a rich graphical experience at high power. Although more energy efficient electrophoretic display technologies have reduced the ongoing power requirements, they still often require high voltages and power to drive the display, negating the possibility of using ambient energy harvesting methods.

Unique 3D layered open porous structure

Implementations disclosed herein provide an EPD display device having a carbon-containing layer positioned between oppositely charged electrode layers. The carbon-containing layer acts as a physical barrier to the electrophoretic ink migrating between the electrode layers to direct and control migration, thereby achieving high image resolution while maintaining low power consumption. The EPD device provides improvements over conventional EPD displays by incorporating three-dimensional (3D) carbon-based aggregates formed from graphene nanoplatelets (where graphene nanoplatelets refer to a relatively new class of carbon nanoparticles and/or nanopowders) in a carbon-containing layer having multifunctional properties. Graphene nanoplatelets may consist of small stacks (3-5 layers, or up to 15 layers) of substantially vertically aligned graphene sheets having a platelet shape. Such graphene sheets can be nearly identical to those found in the walls of carbon nanotubes, but exist in a planar form. Graphene nanoplatelets can replace carbon fibers, carbon nanotubes, nanoclays, or other compounds in many composite applications, including those suitable for use in the EPD devices provided herein.

The 3D carbon-based aggregates formed from graphene nanoplatelets may be synthesized (or otherwise "self-assembled", "self-nucleated", or formed) in a controlled and tunable chemical reaction chamber or reactor while flowing carbon-containing gaseous species therein, the gaseous species optionally including one or more inert carrier gases, or the like. The 3D carbon-based aggregates inherently self-grow in flight at defined locations orthogonal (at right angles) to each other to define a 3D layered open porous structure (the term "layered" is used herein to refer to a plurality of open passages of various widths or other dimensions interspersed in or between larger 3D carbon aggregates). The disclosed self-growth or self-assembly method of the present invention provides significant procedural, synthetic and technical differences from known and conventional carbon particle formation methods, such as annealing (which refers to a heat treatment that changes the physical properties of the material and sometimes changes the chemical properties to increase its ductility and reduce its hardness to make it easier to process) and sintering (which refers to a method of compacting by heat or pressure and forming a solid mass of material without melting it to the point of liquefaction) to exhibit unexpectedly favorable material and performance properties in a 3D layered open porous structure.

In detail with respect to the carbon-containing layer of the proposed EPD device, an organized and tunable porous arrangement is formed in a 3D layered open porous structure configured to facilitate electrophoretic migration of carbon-based electronic ink therein. The porous arrangement may be substantially fixed such that the 3D carbon-based aggregates are cross-linked and may be held in place by a bonding material or adhesive to promote flexibility, which may be desirable for forming porous arrangements on flexible substrates (such as paper, plastic, or other materials), but still direct electrophoretic ink migration as needed. Electrophoretic carbon-based inks can be prepared by using an ultrasonic treatment process in which carbon materials are simultaneously broken up and functionalized to produce submicron ink particles in the range of about 100nm to 200nm that are effectively dispersed in a low dielectric solvent.

The disclosed EPD device, related structures and electrophoretic carbon-based inks can be 3D printed on flexible and disposable substrates, allowing for the development and economically feasible production of low cost devices suitable for everyday use. Compared to conventional EPDs, EPD devices have relatively low power consumption requirements and therefore can be operated at relatively low amounts of power, allowing for devices that can be operated solely by energy harvesting rather than on, for example, portable battery power sources as is occasionally found in conventional EPD devices. As previously discussed, the disclosed apparatus has broad application and includes (at least) a shipping label for packaging or a price label for store items, where information to be displayed on the EPD may be wirelessly transmitted to the EPD. The low cost of an EPD allows it to be discarded after the item to which it is attached has been delivered or purchased, etc.

Conventional electrophoretic display ("EPD") devices

Unlike conventional backlit flat panel displays that emit light, electronic paper displays that include the disclosed EPD devices reflect light like conventional paper, making them natural to the human eye to observe and read, and can also provide wider viewing angles, enabling versatility in applications that replace conventional signage in retail stores and the like. Moreover, many e-paper technologies can hold (render) static text and images indefinitely without power, thus reducing the continuous power consumption requirements of applications in various fields.

Fig. 1A shows a side cross-sectional schematic view 110A of an exemplary conventional EPD device 100A and a top-down view 108A of the EPD device 100A, which includes an upper (transparent) electrode layer 102A, a liquid polymer layer 104A containing electrophoretic ink capsules, and a lower electrode layer 106A. In conventional practice, titanium dioxide ("titania") particles having a diameter of about one micron (μm) are dispersed in a hydrocarbon-based oil. A dark dye may also be added to the oil along with a surfactant (meaning a substance that tends to reduce the surface tension of the liquid in which it is dissolved) and a charging agent that charges the titanium dioxide particles. The mixture was placed between two parallel conductive plates (shown as upper electrode layer 102A and lower electrode layer 106A, respectively) separated by a gap of 10 to 100 μm. When a voltage is applied across the two plates, the particles electrophoretically migrate (meaning the movement of the dispersed particles relative to the fluid under the influence of a spatially uniform electric field) to the plate with the opposite charge to the particles. When the particles are on the front (viewing) side of the display, EPD100A appears white because the titanium dioxide particles scatter light back to the viewer due to their refractive index (a dimensional value that describes how fast the light passes through a given material). When the particles are located on the back side of the display, this part of the EPD appears dark, since the incident light is absorbed by the colored dye. If the rear electrode is divided into a plurality of small picture elements (pixels), an image can be formed by applying appropriate voltages to each area of the display to create a pattern of reflective and absorptive areas.

Conventional EPDs may be configured to be controlled by or with metal oxide field effect transistor (MOSFET) based Thin Film Transistor (TFT) technology. TFTs may be required to form high density images in EPDs. A common application of TFT-based EPDs is electronic readers. EPDs are considered to be a major example of the electronic paper category because of their paper-like appearance and low power consumption. Examples of commercial electrophoretic displays include high resolution active matrix displays used in Amazon Kindle, Barnes & Noble Nook, Sony Reader, and Kobo eReader.

A conventional microcapsule-type electrophoretic display 100B is shown in fig. 1B and includes an array of top electrodes 102B and an array of bottom electrodes 108B, having alternating and opposite polarities or charges, respectively, as shown, as well as white negatively charged particles 104B and a black dye 106B (collectively referred to as electronic ink). EPD holds the microcapsules in a liquid polymer layer sandwiched between two electrode arrays 102B and 108B, with the upper portion being transparent. The two electrode arrays 102B and 108B are aligned to divide the sheet into pixels, and each pixel corresponds to a pair of electrodes located on either side of the sheet. The sheet was laminated with a clear plastic for protection to give a total thickness of 80 microns, or twice that of plain paper. The network of electrode arrays (referring to both electrode arrays 102B and 108B) is connected to display circuitry that turns the electronic ink "on" and "off at a particular pixel by applying a voltage to a particular pair of electrodes. The negative charge of the surface electrode repels the white negatively charged particles 106B to the bottom of the partial capsule, forcing the black dye 106B to the surface to turn the pixel black. Reversing the voltage has the opposite effect. Which attracts the white negatively charged particles 106B to the surface, turning the pixel white.

Ultrathin plastic passive matrix EPD display (PMEPD)

A conventional PMEPD100C using microcup technology is shown in fig. 1C and includes a top patterned conductor film 102C, charged particles 104C, a sealing or adhesive layer 106C, a bottom patterned conductor film 108C, and a dielectric solvent 110C. An exemplary microcup 114C (which may also or alternatively refer to a plurality of microcups as microcups 114C) may have a cup size 112C (meaning width (w) or length (1)) in the range of 60-180 μm and a microcup height 116C of 15-40 μm. The top and bottom patterned conductor films 102C, 108C sandwich one or more microcups, each filled with a dielectric solvent 110C, allowing the migration of charged particles 104C to be guided in accordance with the formation of microcups 114C when exposed to a voltage.

PMEPD has been prepared by a flexible format roll-to-roll manufacturing process based on microcup and sealing technology. High slew rate microcup PMEPD with a threshold voltage in the 5V to 50V range for sharp electrical-to-optical conversion ("γ") has been demonstrated in conventional products and techniques. PMEPDs using conventional column and row electrode patterns typically present significant technical challenges due to the lack of inherent threshold characteristics to suppress or eliminate undesirable crosstalk or cross-offsets between adjacent pixels during matrix driving.

Several attempts have been made to solve the threshold problem. For example, additional conductive layers or grid electrodes have been employed to suppress unwanted particle motion in non-addressed pixels. Such PMEPDs have been developed, but high manufacturing costs are generally required due to the necessary multilayer electrode structure (which itself has high cost). Alternatively, magnetic particles and magnetic electrodes have been proposed to provide the required threshold, again at the expense of manufacturing costs. Electrophoretic fluids have been reported to have inherent threshold characteristics, but there are tradeoffs in, for example, response time, operating voltage, brightness, image uniformity, and display lifetime.

As shown in FIG. 1C, the walls or partitions of the microcups 114C provide mechanical support throughout the EPD and may provide advantageous physico-mechanical properties including scratch resistance, impact resistance, and bending resistance. They also enable color separation by effectively isolating fluids with different characteristics (such as color and/or slew rate) in each individual cup. With continuous fill and seal technology, EPDs can be manufactured in high speed roll-to-roll at relatively low cost.

Limitations in conventional techniques

Although generally produced and operated at lower costs due to their relative simplicity compared to other types of modern flat panel display devices, e-paper technology can provide very low refresh rates (which is undesirable) compared to other display technologies, such as Liquid Crystal Displays (LCDs). This drawback prevents producers from implementing complex modern interactive applications (using, for example, fast moving menus, mouse pointers, or scrolling), such as those commonly found on standard mobile devices, such as smart phones. An example of such a limitation during use is that a document on a conventional EPD device may not scale smoothly without:

(1) extreme blur during conversion; alternatively, the first and second electrodes may be,

(2) very slow scaling (both of which are highly undesirable).

Another limitation is that after refreshing a partial screen, shadows of the image may be visible, leaving an undesirable residue that visually interferes with subsequent images displayed on the screen. Such shadows are a serious nuisance and are known in the industry as "ghost images" and the effect is known as "ghost formation". This effect is reminiscent of screen aging, but unlike screen aging, it can be addressed after a screen refreshes several times.

A novel EPD device comprising a 3D layered open porous structure acting as a stationary phase through which particles can migrate.

To address the limitations encountered in conventional EPD device technology, fig. 1D shows a schematic cross-sectional view of an EPD device 100D that includes a carbon-based three-dimensional (3D) structure 130D and includes tuning openings or vias that are "layered" in nature, such as organized by opening or via width. Thus, structure 130D is generally open and porous. In the configuration shown in fig. 1D, the EPD device 100D includes a plurality of layers 145D deposited on the substrate 110D by any one or more known methods and by using commercially available tools.

As shown in fig. 1D, the EPD device 100D includes a first electrode layer 120D disposed on the substrate 110D, a structure 130D disposed on the first electrode layer 120D, a plurality of charged electrophoretic ink capsules 140D interspersed within and around a porous arrangement 148D formed in the structure 130D, and a second electrode layer 150D disposed thereon. Structure 130D may be sealed with a release sealant layer 139D and laminated to second electrode 150D using an optically transparent (clear) adhesive material 149D. The plurality of charged electrophoretic ink capsules 140D are electrophoretically migrated (referring to the motion of the dispersed particles relative to the fluid under the influence of a spatially uniform electric field) through structures 130D toward layer 150D (relative to the charge of the particles and the charge of the portion of the layer substantially as previously described for the conventional EPD device of fig. 1A-1C, where the charged electrophoretic ink capsules 140D (which may be white and negatively charged) will be attracted to the positively charged first electrode 102B) to form a high resolution image (such as a pattern, graphic, text) viewed from layer 150D, as shown by the icon of eye 105D, and substantially replicate the appearance of conventional ink on paper.

Generally, the structure 130D forms a stationary solid phase between the first electrode layer 120D and the second electrode layer 150D, respectively, and may include porous carbon materials networked together with one another. Including titanium dioxide (interchangeably referred to herein as "titanium oxide", "titanium IV oxide", meaning having TiO)₂Naturally occurring titanium oxide of formula) migrate to any one or more of the first electrode layer 120D and the second electrode layer 150D, respectively, upon application of a voltage. In operation, the negatively charged movable titanium dioxide particles may be attracted to the positively charged first electrode layer 120D to display white, or repelled away from the chargeA negatively charged first electrode layer 120D to cause a black display (or darker than white). Any one or more mobile titanium dioxides may be guided or dragged in and out (non-reactively) by structure 130D (also referred to as the stationary solid phase). This approach can be readily distinguished from conventional techniques that rely on electrophoretic ink dispersed in a dielectric solvent that is trapped or at least substantially confined within the microcups or microcapsules, wherein motion is limited to the organization and placement of any microcups or microcapsules, respectively.

Fabrication of carbon-based 3D layered open porous structures

Conventional EPD devices may be manufactured by a flexible manufacturing process in roll-to-roll format and may include charged titanium dioxide and/or ink particles dispersed in a dielectric solvent within the microcups through which the charged particles migrate to form and display an image. The EPD device may include a hydrocarbon oil positioned between adjacent electrode layers, wherein charged particles migrate through the oil to form an image. The EPD device may also include carbon constructions prepared by annealing or sintering techniques as previously discussed, both of which are conventional and known and do not provide the fidelity required to achieve the structure 130D shown and discussed in fig. 1D.

Unlike the conventional techniques discussed (or others), structure 130D may include methane (CH)₄) To self-form initial carbon-and/or carbon-based particles (without the need for additional dedicated seed particles). The initial particle may be expanded by forming a plurality of orthogonally interconnected aggregates 132D, each aggregate 132D having a diameter of at least 400nm, such as 400nm to 20 μm, or an average diameter such as 1 μm to 20 μm, wherein each aggregate comprises a plurality of graphene nanoplatelets.

The initial particles are then expanded by:

in "in-flight" synthesis, describing the systematic coalescence (meaning the nucleation and/or growth of homogeneous nucleation from an initial carbon group independent of the seed particles) of additional carbon-based material derived from carbon-containing gas entering in mid-air within a microwave plasma reaction chamber; and/or the presence of a gas in the gas,

direct deposition or growth (alternatively referred to as "self-nucleation") onto a supporting or sacrificial substrate such as a current collector within the thermal reactor; and/or

Exposure to one or more post-processing operations to achieve certain desired characteristics.

Coalescence refers to a process in which two phase domains of the same composition come together and form a larger phase domain. Or, a process that seems to "pull" individual pieces of two or more miscible substances (carbon derivatives formed from flowing methane gas) together with each other if they make the slightest contact.

Thus, structure 130D forms a display architecture in which the carbon-based material uniquely self-nucleates to respectively synthesize or otherwise create a tunable porous (non-conductive) network positioned between first electrode layer 120D and second electrode layer 150D that can guide the migratory motion of particles therein and thus create and reproduce a clear high quality image that otherwise could not be achieved by conventional means.

Returning to the synthesis process for forming structure 130, as introduced above, a carbonaceous constituent material such as methane (CH) is included₄) Can flow into one of two general reactor types:

a thermal reactor; alternatively, the first and second electrodes may be,

microwave-based (and/or "microwave") reactors. A suitable type of Microwave Reactor is disclosed in U.S. Pat. No. 9,767,992(2017, 9/19), by Stowell et al, "Microwave Chemical Processing Reactor", which is incorporated herein by reference in its entirety.

As used herein, the term "in-flight" refers to contact with a carbonaceous gaseous material derived from an influent stream (such as containing methane (CH)₄) Those) to "crack" such gaseous species. As generally understood and as referred to herein, "cracking" means a technical process of methane pyrolysis to produce elemental carbon (such as high quality carbon black) and hydrogen, without potential pollution problems of carbon monoxide, and with essentially no carbon dioxide emissions. May be as described aboveA representative endothermic hydrocarbon cracking reaction occurring in a microwave reactor is shown in the following formula (1):

CH₄+74.85kJ/mol→C+2H₂ (1)

the carbon derived from the above-described "cracking" process can fuse (self-combine) together while dispersed in the gas phase, referred to as "in-flight," to form carbon-based particles, structures, (substantially) 2D graphene sheets, and aggregates 132D derived therefrom. The aggregates 132D (collectively defining the structure 130D) may each individually comprise (or consist of) multiple layers of graphene nanoplatelets fused together, each layer fused at an angle orthogonal to adjacent graphene nanoplatelets, to serve as an inherent, self-supporting scaffold of a type that may also be structurally supplemented by conventional chemical (wet) adhesives or other bonding materials, allowing the advantageous structural features of the structure 130D to be maintained even in the event of bending or other movement of the second electrode layer 120D and/or the substrate 110D.

The conductivity of the deposited carbon and/or carbon-based material used to form structure 130D may be tuned (or eliminated) by adding a metal additive to the carbon phase during the first portion of the deposition phase or by varying the ratio of various carbon particles derived from the cracked hydrocarbon gas in question. As part of the energy deposition process, other parameters and/or additions may be adjusted so that the energy level of the deposited carbon and/or carbon-based particles will: (1) are bonded together; alternatively, (2) not bonded together. Also, by nucleating and/or growing the structure 130D "in-flight" or directly in an atmospheric plasma-based vapor stream on a supporting or sacrificial substrate, many of the operations and components present in EPD devices and EPD device manufacturing processes can be reduced or eliminated altogether. Also, customization and tunability may be implemented or added in the carbon and/or carbon-based materials in question.

Pore size of carbon-based 3D layered open porous structures

As described above, the carbon structure 130D may be synthesized in-flight to have a 3D layered structure comprising a combination of short-range, localized nano-structuring, and long-range near-fractal feature structuring, which in this context refers to the formation of successive layers, including 90 degree rotation of each successive layer relative to the layer below, and the like, thereby allowing the formation of vertical (or substantially vertical) layers and/or intermediate ("inter") layers. This orientation is referred to herein as "orthogonal layering" or "orthogonal interconnection" to form structure 130D with porous arrangement 148D formed therein. To achieve the desired EPD performance quality, the porous arrangement 148D may be tuned to include:

interparticle pores 151D, which are void spaces, cavities, or openings within and around the aggregates 132D that extend between a mesopore size and a macropore size (defined by the international union of theory and applied chemistry IUPAC, respectively, as having a pore diameter extending from 2nm and 50nm and greater than 50 nm), and are sized from 200nm to 2 μ ι η, 400nm to 5 μ ι η, or up to 10 μ ι η, which refers to the average distance between the portions of the self-assembled aggregates 132D that form the structure 130D; and

an intra-particle porosity 155D, defined as between materials within each aggregate 132D, such as between graphene layers, and may have an average pore size of 200nm to 2 μm.

Structure 130D may include aggregates 132D interconnected by a polymer (such as a cross-linked polymer).

The substrate 110D may be a flexible material, such as a polymer film or a paper-based material, and is relatively low cost and disposable, particularly suitable for single-use applications. Exemplary materials suitable for forming substrate 110D include any one or more of cardboard, paper, polymer-coated paper and polymer films, and card stock, labels, and boxes. Due to the dormant, non-power consuming nature of EPD100D when not activated, alternative configurations of EPD100 may enable extended periods of use.

Function of electrophoretic display (EPD) device

Any one or more of the first electrode layer 120D and the second electrode layer 150D may incorporate electrical conductors for contacting non-metallic portions of the circuit (such as semiconductors, electrolytes, vacuum, or air) and generating electric fields for various components of the EPD device 100D (such as pixels). The first electrode layer 120D and the second electrode layer 150D may be made of the same, similar, or different materials from each other, respectively. In some implementations, the first electrode layer 120D and the second electrode layer 150D each can include a plurality of individual electrodes positioned substantially adjacent to one another, where any one or more of the individual electrodes are printed by a conductive ink. The potential forming material used to manufacture the electrode layers 120D and 150D may include Indium Tin Oxide (ITO). The second electrode layer 150D is at least substantially transparent to allow viewing of an image formed by the migration of the plurality of charged electrophoretic ink capsules 140D under the guidance of the structure 130D. The second electrode layer 150D may be an ITO-coated film, such as polyethylene terephthalate (PET), while the first electrode layer 120D may be made of a carbonaceous material, such as graphene or metal-functionalized carbon allotropes (including graphene). Carbon particles commonly present in the first electrode layer 120D may be interconnected by a binder such as a polymer including cellulose, cellulose acetate butyrate, styrene butadiene, polyurethane, polyether-polyurethane, or a crosslinkable resin.

Structure 130D may be initially synthesized without the need for nucleation (alternatively referred to as "seed" particles), but may be subsequently exposed to one or more post-processing operations to achieve highly sensitive tuning (in width, length, or any other dimension) of any one or more porous passages of porous arrangement 148D while remaining entirely non-conductive as a whole. The carbon and carbon-based materials may be post-processed (as further described at least in fig. 4B) to prepare the porous arrangement 148D such that the electrophoretic particles may move unobstructed into and out of the structure 130 through the porous arrangement 148D. The unique morphology of the carbon used to create the structure 130 guides the migrating particles without creating, facilitating, or in any way conducting electricity and/or current. In essence, structure 130 is completely non-conductive because one or more processes used to form cross-linked carbon (as detailed in fig. 4B of structure 130) produce a non-conductive material.

Thus, the pores 151D between the carbon particles 132D enable the plurality of charged electrophoretic ink capsules 140D to electrophoretically migrate through the structure 130D (meaning the motion of the dispersed particles relative to the fluid under the influence of a spatially uniform electric field) individually or at least predominantly in response to activation and/or deactivation of any one or more of the first electrode layer 120D and the second electrode layer 150D, respectively, without experiencing undesirable electrical interference from the structure 130D itself. For example, a charged ink capsule of the plurality of charged (typically white or light colored) electrophoretic ink capsules 140D may electrophoretically migrate to the second electrode layer 150D by being guided by the structures 130D to form a detailed visible image of a level of resolution not possible using conventional techniques lacking the unique particle-guiding capabilities of the structures 130. In some configurations, most or all of plurality of charged electrophoretic ink capsules 140D may be light colored to contrast with the dark color of structure 130D.

Most or all of the plurality of charged electrophoretic ink capsules 140D may be titanium dioxide (titanium oxide) or other white colloidal particles of about 100nm dispersed in a low dielectric solvent such as any one or more of isoparaffins, such as Isopar-L and Isopar-G, xylene, 1, 2-dichlorobenzene, tetrahydronaphthalene, diethylbenzene, toluene, decane, dodecane, hexadecane, cyclohexane, 2-phenylhexane, 1-phenylheptane, 1-phenyldecane, tetrachloroethylene. The plurality of charged electrophoretic ink capsules 140D may be configured to include a Charge Control Agent (CCA), such as aerosol di-2-ethylhexyl sodium sulfosuccinate (AOT), poly (isobutylene succinimide) (PIBS), or sorbitan oleate

To have a defined polarity such that they move in response to a voltage difference applied to any one or more of the first electrode layer 120D and the second electrode layer 150D, respectively.

To better maintain a defined overall structural shape or pattern during the bending environment of the substrate 110D, the structure 130D may include aggregates 132D interconnected to one another by a binder, such as a polymer including cellulose, cellulose acetate butyrate, styrene butadiene, polyurethane, polyether-polyurethane, or a crosslinkable resin forming a polymerizable covalent bond, such as an acrylate, epoxy, vinyl. The binder connects the aggregates 132D together, but does not consume or otherwise fill the pores 151D and/or other voids, spaces, or gaps encountered between the aggregates 132D interconnected with one another to form the structure 130D.

In some implementations, the aggregate 132D may include a composition-forming element including a carbon allotrope such as graphene, carbon nano-onions (CNOs), Carbon Nanotubes (CNTs), or any combination thereof, such that in some implementations, the structure 130D may include a defined weight and/or volume percentage of graphene, including greater than 50%, greater than 80%, or greater than 90%. Due to the conductive nature of structure 130D, thickness 131D of structure 130D may be made thinner than conventional EPD materials, which enables electrode connections therein.

Fabricating structure 130D as a thin layer may result in a situation where less energy is required to move multiple charged electrophoretic ink capsules 140D, thus making EPD device 100D more advantageous for powering only by energy harvesting methods, such as energy harvesting Antenna 190D, or other methods disclosed in U.S. patent serial No. 16/282,895 entitled "Antenna with Frequency-Selective Elements" filed 2/22 of 2019 by Stowell et al, which is incorporated herein in its entirety. For example, the thickness 131D of the structure 130D may be configured to be about 10 μm to about 40 μm, or about 10 μm to about 100 μm. The structure 130D may have an electrical conductivity greater than 20,000S/m, or greater than 5,000S/m, or greater than 500S/m, or greater than 50S/m. In terms of electrical resistance, the sheet resistance of structure 130D may be less than 1Ohm/sq, or less than 10Ohm/sq, or less than 100Ohm/sq, or less than 1,000Ohm/sq.

Fig. 1E illustrates an exemplary EPD device 100E, which may include an EPD device 100D having a structure 130D, all shown and discussed in fig. 1D. The exemplary EPD device 100E may generate high resolution text 102E and a map that can be viewed from a wide angle, thereby enhancing the desirability of the EPD device 100E.

Fig. 2A illustrates an enlarged view of a structure 130D (shown in fig. 1D) of an EPD display 100D according to some implementations. As previously shown in fig. 1D, the porous arrangement 148D may be tuned to include:

interparticle pores 151D, which are void spaces, cavities, or openings in and around the aggregates 132D, whose dimensions are set to 200nm to 2 μm, 400nm to 5 μm, or up to 10 μm, refer to the average distance between the portions of the self-assembled aggregates 132D that form the structure 130D; and

an intra-particle porosity 155D, defined as between materials within each aggregate 132D, such as between graphene layers, and may have an average pore size of 200nm to 2 μm.

The aggregates 132D themselves may be sized to have an average diameter of at least about 400nm, such as about 400nm to about 20 μm, or such as about 1 μm to about 20 μm in diameter, and crosslinked together (orthogonally) by the polymer. The detailed view 135 shown in fig. 2B shows a magnified schematic view of an exemplary aggregate 132D comprising organized graphene nanoplatelets orthogonally fused together, each nanoplatelet potentially comprising several layers of graphene (FLG)136 and a single layer of graphene 137. The representative interparticle porosity 138a shown in fig. 2C (another magnified view shown in fig. 2B) is between FLGs 136 (again, in some implementations, FLGs 136 may be aggregates 132B), while the intraparticle porosity 138B is within any one or more FLGs 136, such as between individual graphene layers of graphene, and is sized from about 200nm to about 2 μm.

Fig. 3A and 3B are Scanning Electron Microscope (SEM) photomicrographs of carbon network 300 and carbon network 301 (any one or more of which represents structure 130D shown in fig. 1D), respectively, in which carbon networks 300 and 301 consist only of carbon-based materials (such as aggregate 132D grown "in flight" in an atmospheric vapor stream of a carbon-containing gaseous substance, such as methane, as previously discussed with respect to fig. 1D), without the application or use of a resin to connect aggregate 132D. Fig. 3A shows a carbon network 300 that includes various larger interparticle pores 304 (200 nm to 2 μm, 400nm to 5 μm, or up to 10 μm in size) and smaller intraparticle pores 308 (200 nm to 2 μm in average pore size) of different sizes, as shown by the highly textured 3D configuration of the carbon network 300 shown in fig. 3A. Fig. 3B is a higher magnification photomicrograph of the carbon network 300 shown in fig. 3A, showing the porosity of the carbon network 301. Carbon networks 300 and 301 illustrate exemplary carbon-based porous structures in which a resin material is not used to bond carbon materials together. Under certain use or bending conditions, carbon networks 300 and 301 may break and break down and thus fail to provide guidance for migrating electrophoretic ink particles to form high resolution images, thereby limiting their ability to be applied to electrophoretic displays, such as EPD device 100 shown in fig. 1. To address these potential performance issues, resins (referring to solid or highly viscous materials of plant or synthetic origin that can typically be converted to polymers) can be systematically incorporated into any one or more of carbon networks 300 and 301 for the purpose of reinforcing and retaining the structure so that they can be used in EPD devices without encountering breakage or other performance issues.

Fig. 4A and 4B show a flow chart with accompanying illustrative schematic diagrams 400a and 400B, both of which relate to the fabrication of a carbon-based scaffold or structure, such as structure 130D shown in fig. 1D, and carbon networks 300 and 301 shown in fig. 3A and 3B, respectively, either or more of which are suitable for incorporation into an electrophoretic display, such as EPD device 100D shown in fig. 1D. The graph 400B shown in FIG. 4B represents a continuation of the graph 400a shown in FIG. 4A. In operation 410 of fig. 4A, carbon particles, such as aggregates 132D shown in fig. 1D, may be grown "in-flight" in a substantially atmospheric vapor stream as previously described and/or using a Microwave plasma Reactor and/or the method described in U.S. patent 9,812,295 entitled "Microwave Chemical Processing" or U.S. patent 9,767,992 entitled "Microwave Chemical Processing Reactor," the respective entireties of which are incorporated herein by reference for all purposes. Carbon particles (such as aggregate 132D) may be composed of several smaller carbon-based constituent elements (such as orthogonally fused FLG and/or SLG), as shown in fig. 2B and 2C. Such aggregates may be further deconstructed or decomposed into their constituent nanoparticles in operation 420 to functionalize these nanoparticles with nucleophilic functional groups in operation 430 to facilitate bonding of the crosslinkable monomer to the exposed carbon. The fragmentation and/or functionalization can be carried out in the reactor in which the aggregates are formed, such as during or immediately after their functionalization. Alternatively, or in addition to in situ (within the same reactor) treatment as described, after the aggregate 132D has grown, the fragmentation and/or functionalization can be performed in a post-treatment operation external to the reactor. The nucleophilic moiety added during functionalization can facilitate coupling with the electrophilic moiety of the crosslinkable monomer. The nucleophilic moiety may include, for example, a hydroxide and/or an amine, wherein in the example of fig. 4A, the exposed carbon may be oxidized to form a hydroxylated carbon.

Turning to diagram 400B shown in fig. 4B, the nucleophilic moiety of the functionalized carbon of operation 430 can be converted to a cross-linkable carbon in operation 440 by, for example, functionalizing one or more exposed surfaces of structure 130D shown in fig. 1D with the nucleophilic moiety and adding the monomer to the exposed and/or active surfaces of the carbon nanoparticles. Examples of monomers include portions of oligomers such as polyurethanes, polyethers, or polyesters linked with acrylates or epoxides. An organic coupling agent such as Toluene Diisocyanate (TDI) or methylene diphenyl diisocyanate (MDI) may also be added in operation 440 to further link the bond between the carbon nucleophile and the crosslinkable monomer. Operation 440 may also include combining the carbon nanoparticles with a solvent and a polymer initiator, wherein the polymer initiator will be used later to facilitate crosslinking of the carbon. The polymeric initiator may include Ultraviolet (UV) light or photoinitiators, such as alpha-hydroxy ketones and monoacylphosphines. Specific examples include Irgacure 184, Irgacure 819, Irgacure 1300, Darocur 1173, and Darocur TPO. Thermal initiators such as benzoyl peroxide, 2 '-Azobisisobutyronitrile (AIBN), t-butyl peroxide, 1' -azobis (cyclohexanecarbonitrile), cyclohexanone peroxide, t-butyl peracetate, and 4, 4-azobis (4-cyanovaleric acid) may also (or alternatively) be used. Solvents include, for example, isopropanol, ethanol, 2-methoxyethanol, propylene glycol monomethyl ether acetate, methyl ethyl ketone, cyclohexanone, N-methyl-2-pyrrolidone, N-dimethylformamide, xylene, toluene, methylene chloride, and/or various mixtures and combinations thereof.

An Ultraviolet (UV) and/or thermal curing carbon paste may be formed by adding a solvent and a radical initiator using the material resulting from operation 440. Operation 440 may include washing to remove excess monomer that is not successfully attached to the exposed surface of the carbon particles so that the resulting carbon will have a small number of functional groups on the surface of the carbon particles that are available for cross-linking. In operation 450, a carbon paste is cast into a paste layer 452 and dried to a substrate 454 (such as polyethylene naphthalate, polyethylene terephthalate, polyimide, polycarbonate, and polymethylmethacrylate films) that provides support for the paste layer 452Any one or more of). The solvent in the paste layer 452 may be at least partially removed after casting onto the substrate 454. In operation 460, a pixel pattern for the electrophoretic display is formed by debossing (referring to a concavo-convex embossing technique, which means a process of forming a relief image of protrusions or depressions and designs in paper and other materials, respectively) in the surface of the paste layer, such as by forming a plurality of depressions 463 in the surface of the paste layer 452. After patterning, the cross-linkable carbon in layer 452 is polymerized into structure 462 (similar to structure 130D shown in fig. 1D) by applying UV energy and/or heat. For example, a metal halide type lamp (such as 320nm-390nm, 100 mW/cm)²UVA light) can be used to cure the surface of the carbon paste layer in a 5 minute UV exposure. The resulting layer can be further crosslinked by heating the film at 90 ℃ for 10 minutes. Other free radical polymerization methods known to those of ordinary skill in the art may also or alternatively be used to crosslink the carbon. The structure 462 formed on the substrate 454 may be incorporated into an EPD device 100D, such as the EPD device 100D of figure D1.

Carbonaceous electrophoretic ink capsules (configured to migrate through a carbon structure)

Fig. 5 and 6 illustrate implementations of an exemplary EPD (any one or more of which may be identical or similar to EPD100D shown in fig. 1D) using carbon-containing electrophoretic ink (interchangeably referred to as electronic ink), according to some implementations. Conventional electrophoretic inks may comprise negatively charged white particles and positively charged black particles, and are suspended in a transparent fluid. White and black particles (meaning charged electrophoretic ink microspheres or capsules) can be organized as thin films for incorporation into various end-use applications such as EPD for novel applications in phones, watches, magazines, wearable, electronic readers, and the like, to form detailed human-readable images, where black electrophoretic ink capsules can include carbon black (meaning a material resulting from incomplete combustion of heavy petroleum products such as FCC tar, coal tar, or ethylene cracked tar).

Uniformity of pigment particle size and zeta potential is desirable in EPD device applications because differences in charged particles can lead to corresponding (and undesirable) differences in migration rates upon exposure to an applied electric field, leading to undesirable variations and lack of predictability in the quality of the resulting image. For example, smaller sized particles tend to migrate at a faster rate than larger particles. The disclosed electrophoretic inks include any one or more highly structured carbons, such as graphene, carbon nano-onions (CNOs), Carbon Nanotubes (CNTs), or any combination or derivative of the resulting structures, so as to enable higher particle uniformity and high phase purity of the highly structured carbon than conventional inks, rather than carbon black alone. For example, the provided carbon-containing electrophoretic ink may have greater than 90%, or greater than 95%, or greater than 99% highly structured carbon. The carbon inks of the present invention can be made by simultaneously functionalizing and breaking up the carbon particles, resulting in a more uniform distribution of particle size and a higher dispersion of the carbon particles in the ink. For example, the carbon ink may be monodisperse, have a polydispersity index (PDI) of less than 0.1, or have a narrow particle size distribution of < 0.2.

EPD device 500 of fig. 5 is similar to EPD device 100D shown in fig. 1, where substrate 510 corresponds to the same features as described for substrate 110D, and so on. Unlike EPD device 100D, device 500 utilizes carbon-based ink 540 dispersed within structure 530, and further includes a contrast layer 560 positioned between structure 530 and second electrode layer 550. Since the presence of carbon will cause the color of carbon ink 540 to darken, contrast layer 560 may be used to provide a contrasting color such that when ink 540 is near the bottom surface of layer 560, a user may see the pattern formed by carbon ink 540. For example, the contrast layer 560 may be white, including aluminum dioxide, antimony trioxide, barium sulfate, silicon dioxide, titanium dioxide, zinc sulfide, or other white particles, as opposed to the black color of the carbon ink 540.

FIG. 6 illustrates another EPD display device 600 that may be used with any one or more of the disclosed carbon-containing inks. EPD device 600 of fig. 6 may be substantially similar to EPD device 100D shown in fig. 1D, where substrate 610 corresponds to the same features as described for substrate 110D, and so on. Unlike other EPD implementations, EPD device 600 may include structures 630 having a contrasting color (such as white) to carbon ink 640, rather than structures and inks having the same color as in other exemplary EPD implementations. The structure 630 can be made of a polymer composite that includes light colored (such as white) aggregates 632, such as aluminum dioxide, antimony trioxide, barium sulfate, silicon dioxide, titanium dioxide, zinc sulfide, or other white aggregates. The aggregates 632 in structure 630 may be surface functionalized to achieve crosslinking, such as with acrylate functionality, epoxy groups, or organically modified silica ("ORMOSIL"). The structures 630 may be light reflective such that the carbon ink is not visible when the ink is dispersed away from the viewing surface of the device 600.

Fig. 7A shows a flow diagram 700 and accompanying illustrative schematic for carbon ink used in the fabrication of an EPD device. In operation 710 of fig. 7A, carbon particles (similar or identical to the aggregates 132D shown in fig. 1D) are prepared using a microwave plasma reactor and/or a method as described in any one or more of the aforementioned U.S. patent 9,812,295 and U.S. patent 9,767,992. In operation 720, the carbon particles may be combined with reactive monomers (such as styrene, 4-vinyl-benzyl chloride, and vinyl-benzyl trimethyl ammonium chloride), wherein in operation 730 ultrasonic energy is applied to the mixture to simultaneously break up and functionalize the particles. The carbon particles are broken up into nanoparticles, each of which may have an average size of, for example, less than 200 nm. The sonication in operation 730 also generates free radicals that cause the subparticles to be functionalized with reactive monomers. The monomer is polymerized on the surface of the carbon particles to produce a linear polymer that acts as a dispersant. Operation 730 may also include adding a free radical initiator, such as AIBN or other thermal initiator. In operation 730, the resulting particles may be dispersed in a low dielectric solvent with a Charge Control Agent (CCA), such as AOT, PIBS, or SPAN, to make a carbon-containing electrophoretic ink. In operation 730, the fragmentation and functionalization may be performed together using ultrasonic energy to form particles that are relatively uniform in size and highly dispersed in the electrophoretic ink. Alternatively, the carbon nanomaterial can be oxidized, which can be coupled with fatty acids (such as oleic acid, isopalmitic acid, and isostearic acid) or amines (such as octadecylamine, hexadecylamine, and oleylamine) to make functionalized carbons dispersible in low dielectric solvents. CCA was then added to increase the zeta potential of the carbon particles. The resulting electrophoretic ink may have a high zeta potential value with a magnitude of at least 30mV, such as from about-30 mV to about-60 mV (negative for carbon ink).

Fig. 7B is a schematic diagram representing another method 740 of preparing a carbon ink for an electrophoretic visual display, according to some implementations. Unlike that shown and discussed in fig. 7A, carbon particles can be prepared in a manner similar to operation 710 in operation 750 and reacted with octadecylamine in operation 760 to produce functionalized carbon in operation 770. Also, in some configurations of the disclosed examples and/or implementations, black or dark carbon-based electrophoretic inks may be used to migrate within a white (or light-colored) fixed carbon-based porous matrix or structure. Such functionalized carbons can then be mixed with charge control agents (such as described in example 1) in operation 780.

EPD device configuration

Fig. 8-11 illustrate exemplary configurations of any one or more of the EPD devices disclosed herein using carbon structures (such as the structure 130D shown in fig. 1D) and/or carbon inks, according to some implementations. In these figures, only the electrode and substrate layers are shown for clarity. Moreover, the figures are schematic and not drawn to scale; for example, the dimensions of the recesses and layers may be scaled differently than shown.

Fig. 8 shows a portion of an EPD800 comprising a first electrode layer 820 ("bottom electrode"), a structure 830 (which may be carbon-based or carbon-containing, similar to structure 130D shown in fig. 1D) located on the first electrode layer 820, and a second electrode layer 850 ("top transparent electrode") located on the structure 830. The structure 830 is electrically non-conductive, porous, and made of carbon particles 831. To illustrate the movement of the ink, the ink 840 is shown as a droplet, but it should be understood that the ink 840 includes white sub-micron particles that are injected into the structure 830, which move between the pores of the structure 830 as described above. Ink 840 is an electrophoretic white ink in this implementation and is positively charged.

The first electrode layer 820 and the second electrode layer 850 are shown with pixels 832a, 832b, and 832c, wherein in operation, each pixel of the first electrode layer 820 is oppositely charged from a corresponding pair of pixels in the second electrode layer 850. Because the ink 840 is positively charged, the ink 840 is attracted to the negatively charged pixel 832b of the second electrode layer 850, causing the pixel 832b to appear white in the EPD 800. In contrast, the positively charged pixels 832a and 832c of the second electrode layer 850 appear black due to the absence of the ink 840 at the second electrode layer 850. The pixels 832a, 832b, 832c of the display may have a rectangular, circular, hexagonal, or other shape in the plane of the electrode layer 850, with the pixels forming a pattern such as an orthogonal or diagonal array.

Fig. 9 is a cross-sectional view of an EPD900 illustrating an implementation using a non-conductive, non-porous carbon-based structure 930 instead of the structure 830 of fig. 8. EPD900 also uses color ink 940 in place of white ink 840. Fig. 9 includes a first electrode layer 920 ("bottom electrode"), a non-porous carbon-based structure 930 located on the first electrode layer 920, a porous TiO2 layer 960 located on the non-porous carbon-based structure 930, and a second electrode layer 950 ("top transparent electrode") located on the layer 960. The non-porous carbon-based structure 930 is patterned with a recessed region 935 formed in the non-porous carbon-based structure 930 through which ink 940 may travel. Ink 940 is made of negatively charged electrophoretic carbon. The ink 940 may be black or other color, such as by adding color pigments instead of carbon. The pairs of pixels 932a, 932b, and 932c in the first electrode layer 920 and the second electrode layer 950 are similar to the pixels described above with respect to fig. 8.

In fig. 9, pixel 932b is shown to appear white with no carbon particles in layer 960 (black ink 940), and pixels 932a and 932c are shown to appear ink 940 (porous TiO)₂Ink 940 in layer 960). Pixels 932a, 932b, 932c together form an image on EPD 900. Fig. 9 illustrates one implementation of driving ink, where ink 940 moves vertically between electrode layers 920 and 950 when a voltage is applied between a first electrode in first electrode layer 920 and a second electrode in second electrode layer 950 (e.g., an electrode in each pixel 932a, b, c). The electrodes may be individually addressable by an addressable array in the first electrode layer 920 and the second electrode layer 950, respectively, as will be appreciated by those of ordinary skill in the art. In the example of FIG. 9, the first electrode layer 920 is likeThe first electrode in the pixel 932a has a negative charge and the second electrode in the pixel 932a of the second electrode 950 has a positive charge. Because the ink 940 is negatively charged, the ink 940 will move through the recess 935, towards the second electrode layer 950 and stay within the porous layer 960, becoming visible in the image produced by the EPD 900. When an opposite voltage is applied, the ink 940 will move towards the electrode layer 920 and the pixel 932b will appear blank, as indicated by the negative charge on the pixel 932b of the second electrode layer 950 and the positive charge on the pixel 932b of the first electrode layer 920.

Fig. 10 and 11 show implementations of EPDs 1000 and 1100 that are similar to EPD900, but have openings (e.g., recesses) that are triangular in cross-section. EPD1000 includes a first electrode layer 1020, a non-porous carbon-based structure 1030 on the first electrode layer 1020, a porous TiO2 layer 1060 on the non-porous carbon-based structure 1030, and a porous TiO₂A second electrode layer 1050 on layer 1060. The non-porous carbon-based structure 1030 is electrically non-conductive and non-porous. The recesses 1035 in the non-porous carbon-based structure 1030 have vertices of triangles that point away from the image viewing surface (e.g., away from the second electrode layer 1050). The ink 1040 includes negatively charged electrophoretic carbon. Fig. 10 illustrates a configuration in which the ink 1040 shuttles vertically into and out of the recess 1035 as a result of voltages applied to pixels in the first electrode layer 1020 and the second electrode layer 1050, as described above.

Fig. 11 shows a configuration in which the non-porous structures 1130 are non-porous layers similar to the patterned triangular recesses 1135 of fig. 10, but the non-porous carbon-based structures 1130 are electrically conductive, rather than electrically non-conductive, as is the non-porous carbon-based structures 1030. Bottom electrode 1120, top electrode 1150, and porous TiO of FIG. 11₂Layer 1160 is similar to the corresponding layer in FIG. 10. Porous TiO₂An insulating sealing layer 1170 between the layer 1160 and the top electrode 1150 serves to electrically insulate the non-porous structure 1130 from the top electrode 1150. Examples of sealing compositions for the sealing layer 1170 include thermoplastic precursor dispersions that are immiscible with the electrophoretic ink and have a lower specific density than the ink. After the stationary phase is filled with a mixture of the sealing precursor and the electrophoretic ink, the precursors phase separate and form a thin film on top of the fluidAnd (3) a layer. The layer may then be thermally or radiation polymerized to hermetically seal the stationary phase. Because the non-porous structure 1130 is conductive, the ink 1140 moves toward the entire face (e.g., side walls) of the triangular recess 1135, rather than only toward the downward apex as shown in fig. 10. This implementation may provide a faster response time in forming an image of EPD1100 as compared to EPD1000 because ink 1140 travels a smaller distance.

Fig. 12 and 13 illustrate images of exemplary electrophoretic display units 1200 and 1300, respectively, according to some implementations. When a voltage difference of about ± 1V is applied to any one or more of the display units 1200 or 1300, a contrast image (relative to no electric field) is observed. Similarly, fig. 14 shows an image of an exemplary electrophoretic display unit 1400 indicating programmed indicia that are reconfigurable upon application of a voltage, suitable for e-readers, supermarket displays, and the like, according to some implementations.

Fig. 15A illustrates a cross-sectional view of an exemplary EPD1500A (which may be significantly identical in structure and function to any one or more of EPD130D shown in fig. 1D and/or the EPD devices disclosed herein) according to some implementations. EPD1500A may include one or more layers including protective layer 1502A, transparent conductive layer 1504A, porous reflective layer 1506A, porous carbon matrix with integrated microporous layer 1508A, sealing layer 1510A, and flexible layer 1512A (similar to a substrate on which any one or more other layers may be formed or deposited). Protective layer 1502A may be substantially transparent, providing greater than 90% transparency in the visible range, and may also be tuned or configured as desired for a particular end use scenario (such as a supermarket or grocery store application as opposed to an e-reader application). The protective layer 1502A may be deposited on top of the transparent conductive layer 1504A, which may have about R_S＜100Ω/sq→R_SA resistance value of < 30 Ω/sq (or in the approximate range thereof). Transparent conductive layer 1504A can be deposited on porous reflective layer 1506A, which is optional in some configurations and can be achieved based on the color of the carbon-based ink. Porous reflective layer 1506A may be deposited on a porous carbon substrate with integrated microporous layer 1508AThe structure may be substantially identical in form and function to the structure 130D shown in fig. 1D, including pores of about 20 μm in size, or other sizes depending on, for example, the size of the carbonaceous electrophoretic ink particles or capsules used. The porous carbon matrix with integrated microporous layer 1508A may be deposited on sealing layer 1510A, which may be configured to include or otherwise abut or be held together with the carbon-doped polymer. Sealing layer 1510A may be deposited on flexible layer 1512A, which may substantially mimic the function of any one or more of the substrates disclosed herein to complete multilayer exemplary EPD 1500A.

Fig. 15B illustrates a list of features 1500B associated with a multi-layer electrophoretic display according to some implementations. The top electrode (not shown in fig. 15A) used with exemplary EPD1500A may include or be formed from an optically transparent conductor that is electrically conductive but does not contain silver (Ag). The porous carbon substrate with the integrated microcell layer 1508A may include patterned microcups, microcapsules, or recessed regions configured to enhance electrophoretic ink migration therein for optimal image formation quality at reduced power consumption levels. The first electrode layer and the second electrode layer (not shown in fig. 15A) may be prepared to be solvent resistant. All of the transparent components of exemplary EPD1500A may contain carbon, such as including any one or more highly structured carbons associated with implementations disclosed herein.

Fig. 16A shows an exemplary implementation of a multi-layer electrophoretic display 1600 disposed on a container 1610. Multilayer electrophoretic display 1600 may be the same as or different from EPD device 600 described previously. In this example, the EPD device 600 is disposed proximate to other components that interoperate to form a sensor system having a visual readout 1601. In some cases, and as shown, the container (e.g., shipping carton, envelope, etc.) has a surface on which one or more sensors and visual readout devices can be printed. In some cases, the one or more sensors and the one or more visual readout devices are interconnected to form an analyte sensor system that can be printed (e.g., 3D printed, ink jet printed, lithographically printed, etc.) onto one or more labels, which in turn are affixed to the container.

Fig. 16A shows an exploded view of a sample configuration of a set of components that interoperate to form an analyte sensor system for detecting a fluid (e.g., gas or liquid) analyte and for displaying (e.g., visual readout 1601) an indication of the presence and/or concentration of the analyte. A multi-layer electrophoretic display may be made up of any number and/or juxtaposition of pixels. The analyte sensors of the analyte sensor system may be electrochemical, high frequency, resonant, chemiluminescent, or any combination of these. In some cases, the first analyte sensor and the second analyte sensor are printed on the same substrate (e.g., a label or a container surface). Each analyte sensor may include a first electrode, a second electrode, and an electrolyte, some of which include particulate carbon and a redox mediator. Analyte sensor arrays can be used to add functionality, such as the ability to detect multiple gases and/or subtract background levels and/or increase sensitivity to any particular analyte. As shown, EPD device 600 is coupled to analyte sensor 1660 by power and signal interconnect 1650.

Multiple analyte sensors disposed on one container can be utilized in concert to detect a combination of chemicals, which in turn leads to characterization of the entire compound. The presence of multiple analyte sensors can be used to exclude false positives. Such multi-analyte sensor systems may include a first sensor configured to detect a first target chemical, and a second sensor configured to detect a second target chemical different from the first target chemical. An indicator, such as the illustrated EPD device 600, presents a visual indication if and when a first sensor positively detects a first target chemical and a second sensor positively detects a second target chemical. For example, a first concentric ring may be displayed (e.g., as a visual readout 1601) if and when a first sensor positively detects a first target chemical, and a second concentric ring may be displayed if and when a second sensor positively detects a second target chemical.

In addition, other components may be integrated with the analyte sensor system to add additional functionality to the analyte sensor system. For example, the energy harvesting antenna 1670 may provide the electrical power required by the sensor and/or the display. Further details regarding the general method of making and using energy harvesting antennas are described in U.S. application serial No. 16/282,895 entitled "Antenna with Frequency-Selective Elements," filed on 22.2.2019, which is hereby incorporated by reference in its entirety.

As another example for providing the electrical power required by the sensor and/or the display, an energy storage device (not shown) may be disposed proximate the sensor and/or proximate the display. Further details regarding the general method of making and using energy storage devices are described in U.S. application Ser. No. 16/740,381 entitled "Multi-PART NONTOXIC PRINTEDBATTERIES" filed on 10.1.2020, which is hereby incorporated by reference in its entirety.

Strictly as a non-limiting variation of an electroactive label with a display system printed thereon, the electroactive label may comprise an EPD device configured to display telemetry data, Q-codes or bar codes and/or icons. Exemplary variants include telemetry data that may update information, and/or images with any variation using numerical data and/or alpha or alphanumeric text formats (e.g., metrology images, Q-code images, QR-code images, or barcode images, etc.). In some implementations, the color changes or image changes are displayed in sequence. In such implementations, a change in the display, such as a change in one or more colors of a displayed symbol or image, or a chronological back-and-forth change, may be used to indicate any current condition, such as a condition of the surrounding environment, or a change in the display to indicate the presence of an analyte, or a condition of the container contents, etc.

The device may also optionally include low power communication components such as may be configured to communicate with other electronic devices. In some non-limiting examples, a cardboard shipping container is equipped with a first electrochemical sensor similar to analyte sensor 1660 and a second electrochemical sensor that is a variant of analyte sensor 1660. The energy harvesting and/or energy storage device drives the sensor and display device.

The beneficial properties of the particulate carbon in combination with the aforementioned sensor design enable very low power devices, such as devices operating at currents of 0.1 to 5 microamperes and voltages on the order of 1 volt. This example illustrates that analyte sensors utilizing the particulate carbon described herein can be prepared using low cost, low power driver/detection electronics that can be integrated onto the surface of even small packages. Furthermore, this example shows that such low cost printed displays can also be integrated with other system components such as analyte sensors, energy harvesters, batteries, and communication chips.

In some cases, as shown in fig. 16B, two different sets of components may be printed on two different substrates, which may then be combined into a single detection and display system when in use. In the described and other detection and display systems, the features of the first set of components 1661 can be different than the features of the second set of components 1662, and thus, the first set of components 1661 can be disposed on a first substrate 1641 and the second set of components 1662 can be disposed on a second substrate 1642. Electrical connectivity (e.g., for power supply and/or for electrical signal conduction) may be provided by the mated conductive terminals. In the example of fig. 16B, mating positive polarity terminals (e.g., first positive terminal 1651, second positive terminal 1652) and mating negative polarity terminals (e.g., first negative terminal 1653, second negative terminal 1654) provide power. In other implementations, additional counterpart terminals can be configured to provide signal conduction between members of the first set of components 1661 and members of the second set of components 1662. Further, where the features of the first set of components 1661 are different than the features of the second set of components 1662, the printing techniques may be different than forming the first set of components 1661 on the first substrate 1641 and forming the second set of components 1662 on the second substrate 1642.

Any of the above-described printing techniques can be used in various arrangements for constructing the first set of components or the second set of components 1662. In some cases, the composition and/or characteristics of any one or more layers of the component may indicate the use of high-energy lithography. More specifically, where a slurry is required (e.g., to form an electrolyte), and/or when the 3D structure is deeper in the depth dimension than can be formed using the aforementioned 3D printing techniques, and/or when a binder is required to provide mechanical integrity to a portion of the device, and/or when higher throughput is required than can be provided using additive 3D printing techniques, then the use of subtractive high-energy photolithography may be indicated. In some cases, a first set of components of the first substrate is printed using a first printing technique, while a second set of components of the second substrate is printed using a second printing technique.

Strictly as an example and referring again to the second set of components 1662 disposed on the second substrate 1642, the second set of components may be formed by photolithography using light having a wavelength in the ultraviolet range. More specifically, various techniques for performing Vacuum Ultraviolet (VUV) lithography may be applied.

In some cases, the pressures involved when performing VUV lithography may be pressures other than vacuum or near vacuum. In fact, the pressure of some printing/deposition techniques is much higher than atmospheric pressure. Furthermore, to support a wide range of pressures used in performing VUV lithography, the illumination wavelength is selected to be in a region of low air absorption, so that a vacuum environment is not required for high energy lithography. This flexibility with respect to wavelength and pressure in use results in higher print throughput when performing VUV lithography.

The selection of the wavelength of light (in the range of about 120nm to about 172nm, which corresponds to photon energies of about 7eV to about 10.1960 eV) results in achieving the desired feature size. In the context of the present disclosure, small feature sizes (e.g., 1 micron, 0.5 micron, 0.25 micron, and smaller) may result in smaller and smaller display pixels, which in turn results in displays with higher and higher resolutions.

Examples

Example 1, electrophoretic ink 1.

Graphene is prepared using any one or more of the aforementioned techniques and/or methods reported in U.S. patent 9,812,295 entitled "Microwave Chemical Processing" or U.S. patent 9,767,992 entitled "Microwave Chemical Processing Reactor". 10g of graphene was added to iceIn 250mL of 96% sulfuric acid cooled in a bath and the resulting mixture is stirred for at least 90 minutes. 50g of KMnO₄Was added slowly to the reaction mixture to prevent any heating. After stirring for 30 minutes, the reaction mixture was heated to 35 ℃ and stirred for a further 2 hours. Initial addition of 450mL H2O and 50mL H₂O₂Then 700mL of H was added₂And O. The reaction mixture was filtered and washed with 5% HCl and copious amounts of H₂And washing with O until the pH value of the eluent reaches 7 to obtain the graphene oxide.

300mg of graphene oxide was dispersed and sonicated in 30mL H using a probe sonicator (sonic VCX 750) set to 30% amplitude₂Sonicate in O for 2 hours. The ultrasonic treatment yielded submicron particles having an average particle diameter of 149nm, which were measured by a dynamic light scattering method. Next, a solution of 500mg of Octadecylamine (ODA) in 50mL of ethanol was added and refluxed overnight. The resulting ODA-functionalized graphene particles were washed with 50mL of H₂O wash, then 3x50mL ethanol wash. To prepare the electrophoretic ink, 150mg of ODA-functionalized graphene was mixed with 150mg of Span 80 in 3.75g of 1, 2, 3, 4-tetralin (tetralin). The mixture was mixed in an ultrasonic bath for 1 hour and then filtered through a 0.7um glass fiber filter to obtain an electrophoretic graphene ink.

Example 2, electrophoretic ink 2.

Example 1 was repeated using Carbon Nano Onions (CNO) instead of graphene to prepare CNO-based inks.

Example 3, electrophoretic ink 3.

Dispersing 900mg of graphene in 90mL of CH₂Cl₂Neutralized and irradiated with an ultrasonic probe at 20kHz and 0 ℃. After 2 hours of sonication, the average particle size was 191nm, which was measured using dynamic light scattering. To the broken carbon dispersion was added a solution of 9.0g tetrabutylammonium bromide in 15mL H2O, 1.2g KMnO₄Solution in 15mL H2O and 40mL acetic acid, and the mixture was stirred overnight. The resulting graphene hydroxide was washed with aqueous ethanol (50 wt%, 100mL) at least 5 times to remove impurities. 5g of oleic acid was added to a solution of 500mg of graphene hydroxide in 100mL of hexane, and the mixture was stirred at 60 ℃ for 20 hours. By separation ofThe core obtained oleic acid functionalized carbon, which was washed at least three times with 30mL of hexane. To prepare the electrophoretic ink, 100mg oleic acid functionalized graphene was mixed with 100mg Span 85 in 2.5g dodecane. The mixture was mixed in an ultrasonic bath for 1 hour and then filtered through a 0.7 μm glass fiber filter to obtain an electrophoretic ink.

Example 4, electrophoretic ink 4.

2g of graphene, 100mg of benzoyl peroxide, 350g of styrene and 700mL of toluene were added to a round bottom flask. The reaction mixture was degassed by bubbling argon for 1 hour and then irradiated with 20kHz high intensity ultrasound at 0 ℃ for 2 hours. The mixture was filtered through a Teflon filter (0.22um) and washed at least three times with toluene. Polystyrene functionalized graphene (100mg) was dried and redispersed in xylene (2.5g) with 100mg Span 85 using an ultrasonic bath to prepare an electrophoretic ink.

Example 5, crosslinkable carbon material.

10g of the graphene hydroxide prepared in example 3 was dispersed in 1L of DMF with an ultrasonicator. After degassing the dispersed solution with nitrogen, 0.5mL of dibutyltin dilaurate was added and 300g of toluene diisocyanate pre-dissolved in 200mL of DMF were added dropwise at 70 ℃. After stirring for 4 hours, the reaction mixture was cooled to 50 ℃, then 300g of hydroxyethyl acrylate was added dropwise and the mixture was stirred for another 12 hours. Finally, acrylate functionalized graphene was obtained by vacuum filtration and washing with dichloromethane. To prepare a cross-linkable carbon formulation, 10g of acrylate functionalized graphene was dispersed in 10mL of a 1: 1 mixture of ethanol and xylene, along with 500mg of Darocur 1173 and 500mg of benzoyl peroxide. The resulting formulation was mixed with a mechanical stirrer.

Example 6, electrophoretic display unit 1.

The ITO coated PET was coated with the cross-linkable carbon formulation prepared as described in example 5 using a doctor blade with a 50 μm gap. After removal of the solvent, the resulting film was cured with UVA light at 100mW/cm2 for 5 minutes, followed by heat treatment at 90 ℃ for 10 minutes. The individual ITO-coated glasses were coated with a titanium dioxide/polyacrylate composite. Electrophoretic ink 1 was added between the ITO glasses and then sealed using an epoxy sealant. Applying ± 1V to the display unit shows a contrast image as shown in fig. 12.

Example 7, electrophoretic display unit 2.

Example 6 was repeated using electrophoretic ink 2 as shown in fig. 13.

Example 8, electrophoretic display unit 3.

Example 6 was repeated using electrophoretic ink 2 as shown in fig. 14 to form a text image.

Reference has been made to implementations of the invention disclosed herein. Each example has been provided by way of explanation of the technology of the present invention, and not as a limitation of the technology. In fact, while the specification has been described in detail with reference to specific implementations of the invention, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing, may readily conceive of alterations to, variations of, and equivalents to these implementations. For instance, features illustrated or described as part of one implementation can be used with another implementation to yield a still further implementation. Accordingly, it is intended that the present subject matter cover all such modifications and variations as come within the scope of the appended claims and their equivalents. These and other modifications and variations to the present invention may be practiced by those of ordinary skill in the art, without departing from the scope of the present invention, which is more particularly set forth in the appended claims. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention.

Claims (24)

1. An electrophoretic display system, comprising:

a first electrode disposed on a substrate;

a second electrode disposed on the substrate; and

a three-dimensional (3D) carbon-based structure, the 3D carbon-based structure disposed between the first electrode and the second electrode, the 3D carbon-based structure configured to guide migration of charged electrophoretic ink particles dispersed throughout the 3D carbon-based structure, the charged electrophoretic ink particles responsive to application of a voltage across the first electrode, the 3D carbon-based structure comprising:

a plurality of 3D aggregates defined by the morphology of graphene nanoplatelets orthogonally fused together and crosslinked by a polymer; and

a plurality of channels interspersed throughout the 3D carbon-based structure defined by the morphology, each channel of the plurality of channels comprising at least one of an inter-particle passage or an intra-particle passage.

2. The electrophoretic display system of claim 1, wherein the intra-particle vias have a smaller size than the inter-particle vias.

3. The electrophoretic display system of claim 1, further comprising a plurality of recesses formed in any one or more of the plurality of 3D aggregates or the plurality of channels.

4. The electrophoretic display system of claim 1, wherein a plurality of the interparticle passageways have an average radial dimension of no greater than about 10 μm.

5. The electrophoretic display system of claim 1, wherein the intra-particle pathways have an average radial dimension greater than about 200 nm.

6. The electrophoretic display system of claim 1, wherein each 3D aggregate further comprises any one or more of graphene, carbon nano-onions, carbon nano-platelets, or carbon nanotubes.

7. The electrophoretic display system of claim 1, wherein the plurality of 3D aggregates are cross-linked to each other.

8. The electrophoretic display system of claim 1, wherein the polymer comprises any one or more of cellulose, cellulose acetate butyrate, styrene butadiene, polyurethane, polyether-polyurethane, acrylate, epoxy, or vinyl.

9. A method of making an electrophoretic display structure, the method comprising:

self-nucleating a three-dimensional (3D) open porous structure defined by a plurality of 3D carbon-based aggregates from a carbon vapor-containing stream;

functionalizing one or more exposed surfaces of the 3D open porous structure with a nucleophilic moiety; and

cross-linking the plurality of 3D carbon-based aggregates in the 3D open porous structure by defining a porosity in the 3D open porous structure.

10. The method of claim 9, wherein the self-nucleation of the 3D open porous structure further comprises defining a porosity having an average pore diameter greater than about 200 nm.

11. The method of claim 9, wherein the self-nucleation of the 3D open porous structure further comprises forming a plurality of passages in the 3D open porous structure defined by the plurality of 3D carbon-based aggregates.

12. The method of claim 11, wherein the plurality of passageways are configured to direct a plurality of charged movable titanium dioxide particles toward a charged electrode disposed on the electrophoretic display structure.

13. The method of claim 12, wherein the plurality of charged movable titanium dioxide particles are configured to be non-reactively dragged into or out of the 3D open porous structure.

14. A display device, the display device comprising:

a pair of electrodes disposed on a substrate; and

a three-dimensional (3D) carbon-based structure disposed between the pair of electrodes and configured to direct migration of a plurality of charged electrophoretic ink particles dispersed throughout the 3D carbon-based structure based on application of a voltage difference across the pair of electrodes, the 3D carbon-based structure comprising:

a plurality of 3D aggregates defined by the morphology of graphene nanoplatelets orthogonally fused together and crosslinked by a polymer; and

a plurality of channels interspersed throughout the 3D carbon-based structure defined by the morphology, each channel of the plurality of channels comprising at least one of an inter-particle passage or an intra-particle passage.

15. The electrophoretic display system of claim 14, wherein the intra-particle vias have a smaller size than the inter-particle vias.

16. The display device of claim 14, wherein the 3D carbon-based structure is independent of any one or more of microcups or microcapsules.

17. The display device of claim 14, wherein the plurality of charged electrophoretic ink particles further comprises a plurality of negatively charged movable titanium dioxide particles.

18. The display device of claim 14, wherein the negatively charged movable titanium dioxide particles are configured to display a substantially white color.

19. The display device of claim 14, wherein the 3D carbon-based structure is configured in a non-conductive state.

20. The display device of claim 19, wherein the plurality of negatively charged movable titanium dioxide particles are configured to be non-reactively guided through the 3D carbon-based structure when the 3D carbon-based structure is in the non-conductive state.

21. The display device of claim 14, further comprising an antenna configured to provide power to the display device.

22. The display device of claim 14, further comprising a contrast layer disposed between the 3D carbon-based structure and the pair of electrodes.

23. The display device of claim 22, wherein the contrast layer is a first color and the plurality of charged electrophoretic ink particles are a second color different from the first color.

24. The display of claim 14, wherein the 3D carbon-based structure is defined by a polydispersity index of less than about 0.5.

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