KR102503275B1 - Electrophoresis display apparatus and microcapsule for electrophoresis display apparatus - Google Patents

Abstract

According to an embodiment of the present invention, an electrophoretic display device capable of displaying three or more colors and a microcapsule for the electrophoretic display device are disclosed. The electrophoretic display device includes a display layer including a plurality of pixel electrodes, a common electrode, and display cells arranged between the pixel electrodes and the common electrode. Each of the display cells includes a first color solution having a first color and a first density, a second color solution having a second color different from the first color and having a second density greater than the first density, and the second color solution having a second density greater than the first density. It includes electrophoretic particles dispersed in the first color solution and the second color solution and charged with a first polarity.

Description

Electrophoresis display apparatus and microcapsule for electrophoresis display apparatus {Electrophoresis display apparatus and microcapsule for electrophoresis display apparatus}

The present invention relates to an electrophoretic display device and a microcapsule for the electrophoretic display device.

In order to express three or more colors using an electrophoretic display device, one of the reflective display devices, it was necessary to use color filters, inject two or more color particles into one display cell, or use two or more types of display cells. .

When a color filter is used, light incident from the outside passes through the color filter and passes through the color filter while being reflected on the display layer again, resulting in high light loss. Accordingly, overall reflectance and color reproducibility are lowered, contrast ratio is lowered, and manufacturing cost is increased due to the color filter.

In the case of a method using two or more types of microcapsules containing color inks of different colors, a process of arranging each type of microcapsules at a predetermined position is required. Even in the case of the barrier rib method, a process of injecting ink of a predetermined color into the micro cells defined by the barrier rib is required. Accordingly, there is a problem that not only productivity and yield are lowered, but also manufacturing cost is increased.

One problem to be solved by the present invention is to provide an electrophoretic display device and microcapsules for the electrophoretic display device that can be manufactured by a simple process and can express three or more colors.

An electrophoretic display device according to an aspect of the present invention includes a display layer including a plurality of pixel electrodes, a common electrode, and display cells arranged between the pixel electrodes and the common electrode. Each of the display cells includes a first color solution having a first color and a first density, a second color solution having a second color different from the first color and having a second density greater than the first density, and the second color solution having a second density greater than the first density. It includes electrophoretic particles dispersed in the first color solution and the second color solution and charged with a first polarity.

The first color solution and the second color solution may be phase-separated from each other within the display cell.

The first color solution may be positioned on the second color solution due to a density difference.

The electrophoretic particles are controlled to be positioned on the first color solution, between the first color solution and the second color solution, or under the second color solution by an electric field between the pixel electrodes and a common electrode. It can be.

When the electrophoretic particles are white, the first color of the first color solution is displayed when the electrophoretic particles are positioned between the first color solution and the second color solution, and the electrophoretic particles When they are positioned below the second color solution, a third color obtained by mixing the first color of the first color solution and the second color of the second color solution may be displayed.

The first color solution may include a first solvent and a first dye dissolved in the first solvent, and the second color solution may include a second solvent and a second dye dissolved in the second solvent.

The first dye may be insoluble in the second solvent, and the second dye may be insoluble in the first solvent.

Each of the display cells may include a microcapsule having a capsule outer wall surrounding the first color solution, the second color solution, and the electrophoretic particles.

The display layer may include barrier ribs separating the display cells from each other.

An electrophoretic display device according to another aspect of the present invention includes a display layer including a plurality of pixel electrodes, a common electrode, and display cells arranged between the pixel electrodes and the common electrode. Each of the display cells may include: a first color solution having a first color and a first density; a second color solution having a second color different from the first color and having a second density greater than the first density; and a third color solution having a third color different from the second color and having a third density greater than the second density, and electrophoretic particles dispersed in the first to third color solutions and charged with a first polarity. include

The first to third color solutions may be phase separated from each other within the display cell.

The first color solution may be positioned on the second color solution due to a density difference, and the second color solution may be positioned on the third color solution due to a density difference.

The electrophoretic particles are formed on the first color solution, between the first color solution and the second color solution, and between the second color solution and the third color solution by an electric field between the pixel electrodes and the common electrode. It may be controlled to be located between, or below the third color solution.

When the electrophoretic particles are white, the electrophoretic particles display the first color when positioned between the first color solution and the second color solution, and the electrophoretic particles are in the second color solution. and the third color solution, displaying a fourth color in which the first color and the second color are mixed, and when the electrophoretic particles are positioned below the third color solution, the first color solution A fifth color in which all of the through third colors are mixed may be displayed.

The first color solution includes a first solvent and a first dye dissolved in the first solvent, the second color solution includes a second solvent and a second dye dissolved in the second solvent, The three-color solution may include a third solvent and a third dye dissolved in the third solvent.

The first dye is insoluble in the second solvent and the third solvent, the second dye is insoluble in the first solvent and the third solvent, and the third dye is insoluble in the first solvent and the third solvent. 2 May be insoluble in solvents.

A microcapsule for an electrophoretic display device according to an aspect of the present invention includes a first color solution having a first color and a first density, a second color having a second color different from the first color and having a second density greater than the first density. A second color solution having a, electrophoretic particles dispersed in the first color solution and the second color solution and charged with a first polarity, and the first color solution, the second color solution, and the electrophoretic particles enclosing the capsule outer wall.

The first and second color solutions may be phase-separated from each other in the display cell, and the first color solution may be positioned on the second color solution due to a density difference.

The first color solution includes a first solvent and a first dye dissolved in the first solvent and having the first color, and the second color solution is dissolved in a second solvent and the second dye is dissolved in the second solvent. A second dye having a color may be included, the first dye may be insoluble in the second solvent, and the second dye may be insoluble in the first solvent.

It may further include a third color solution having a third color different from the first and second colors and having a third density greater than the second density.

The electrophoretic display device and the microcapsule for the electrophoretic display device according to the present invention can express three or more colors and can be manufactured by a simple process.

1 is a schematic cross-sectional view of an electrophoretic display device according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view according to an enlarged example of the display layer of FIG. 1 .
3 is a cross-sectional view according to another example in which the display layer of FIG. 1 is enlarged.
4A to 4C are schematic cross-sectional views for explaining the operation of the display layer of FIG. 2 .
Figure 5a is a cross-sectional view according to another example of the microcapsule shown in Figure 2.
FIG. 5B is a cross-sectional view of another example of the display cell shown in FIG. 3 .
6A to 6D are schematic cross-sectional views for explaining the operation of the display layer including the microcapsules of FIG. 5A.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and the following examples may be modified in many different forms, and the scope of the present invention It is not limited to the examples below. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the spirit of the invention to those skilled in the art.

Terms used in this specification are used to describe specific embodiments and are not intended to limit the present invention. As used herein, the singular form may include the plural form unless the context clearly indicates otherwise. Also, when used herein, "comprise" and/or "comprising" specifies the presence of the recited shapes, numbers, steps, operations, elements, elements, and/or groups thereof. and does not exclude the presence or addition of one or more other shapes, numbers, operations, elements, elements and/or groups. As used herein, the term "and/or" includes any one and all combinations of one or more of the listed items.

Although terms such as first and second are used in this specification to describe various members, regions, and/or regions, it is obvious that these members, components, regions, layers, and/or regions should not be limited by these terms. do. These terms do not imply any particular order, top or bottom, or superiority or inferiority, and are used only to distinguish one member, region, or region from another member, region, or region. Thus, a first element, region or region described in detail below may refer to a second element, region or region without departing from the teachings of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to drawings schematically showing ideal embodiments of the present invention. In the drawings, variations of the depicted shape may be expected, depending, for example, on manufacturing techniques and/or tolerances. Therefore, the embodiments of the present invention should not be construed as being limited to the specific shape of the region shown in this specification, but should include, for example, a change in shape caused by manufacturing.

1 is a schematic cross-sectional view of an electrophoretic display device according to an embodiment of the present invention.

Referring to FIG. 1 , the electrophoretic display device 100 includes a plurality of pixel electrodes 120, a common electrode 150, and a display layer 140 between the pixel electrodes 120 and the common electrode 150. include The display layer 140 includes display cells arranged between the pixel electrodes 120 and the common electrode 150 .

According to one example, the display cells may include microcapsules 142 as shown in FIG. 2 , for example. According to another example, as shown in FIG. 3 , the display cells 142a may be defined by barrier ribs 143a. The display cells are described in more detail below with reference to FIGS. 2 and 3 .

According to an embodiment, the electrophoretic display device 100 includes a lower substrate 110, pixel electrodes 120 arranged on the lower substrate 110, an adhesive layer 130 on the pixel electrodes 120, and an adhesive layer. 140 on the display layer 140 , the common electrode 150 on the display layer 140 , and the upper substrate 160 on the common electrode 150 . According to an example, shapes such as characters or figures displayed through the display layer 140 are viewed by a viewer in an upward direction through the upper substrate 160 . However, it is not limited thereto, and shapes displayed through the display layer 140 are recognized by a viewer in a downward direction through the lower substrate 110 or in both directions through the upper substrate 160 and the lower substrate 110. It can be recognized by viewers.

The lower substrate 110 may be a substrate made of various materials such as plastic. For example, the lower substrate 110 may be made of an insulating organic material, such as polyethersulphone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethylene naphthalate ( PEN, polyethyelenen napthalate, polyethylene terephthalate (PET, polyethyeleneterepthalate), polyphenylene sulfide (PPS), polyallylate, polyimide, polycarbonate (PC), cellulose triacetate (TAC) ), etc., but is not limited thereto. The lower substrate 110 may be a substrate made of a flexible material that can be bent, bent, or rolled. According to another example, the lower substrate 110 may be a rigid substrate made of a phenol-based or epoxy-based synthetic resin.

Although not shown, a connection electrode (not shown) connected to the common electrode 150 through a through electrode (not shown) penetrating the display layer 140 may be disposed on the lower substrate 110 . Also, wirings (not shown) connected to the pixel electrodes 120 and the connection electrodes, and connection pads (not shown) connected to the wirings may be disposed on the lower substrate 110 . A driving chip (not shown) may be mounted on the lower substrate 110 to provide driving voltages and reference voltages to the pixel electrodes 120 and the connection electrode through connection pads. The driving chip may apply independent voltages to the pixel electrodes 120 .

The pixel electrodes 120 may have a single-layer structure of copper, aluminum, indium tin oxide (ITO) or indium zinc oxide (IZO), or a first material layer such as copper, aluminum, ITO, or IZO. A multi-layered structure may be formed in which a second material layer such as nickel or gold is additionally stacked on the layer.

The pixel electrodes 120 may have various planar shapes and may be disposed on the lower substrate 110 according to a designer's design. The pixel electrodes 120 may have different planar shapes and sizes according to designs. The pixel electrodes 120 are spaced apart from each other on the lower substrate 110 . Depending on the design, some of the pixel electrodes 120 may be electrically connected to each other through wires on the lower substrate 110 .

The lower substrate 110 on which the pixel electrodes 120 are formed may be a printed circuit board. The pixel electrodes 120 may be formed on the lower substrate 110 by a printing method. The pixel electrodes 120 may be formed on the lower substrate 110 using a roll-to-roll process. An active switching element using a semiconductor material, for example, a thin film transistor, may not be directly formed on the lower substrate 110 .

The adhesive layer 130 may be disposed on the pixel electrodes 120 to provide adhesive force so that the pixel electrodes 120 and the display layer 140 are bonded to each other. According to one example, the adhesive layer 130 may be formed using a pressure sensitive adhesive (PSA). The pressure-sensitive adhesive can be used as a material that prevents a change in the optical properties of constituent members and does not require a high-temperature process during curing or drying during bonding treatment.

For example, the adhesive layer 130 may use an appropriate polymer such as an acrylic polymer or a silicone polymer, polyester or polyurethane, polyether or synthetic rubber. The adhesive layer 130 may be melted by heat, and may have adhesiveness when melted by heat. The adhesive layer 130 may be cured by energy (eg, heat or UV). According to another example, the adhesive layer 130 may not be hardened according to design. According to another example, the adhesive layer 130 may be a thermoplastic resin material, for example, a hot melt adhesive material that melts at a temperature between 80 degrees and 120 degrees and has adhesive properties.

The display layer 140 is disposed on the adhesive layer 130 and is positioned between the common electrode 150 and the pixel electrodes 120, and is dependent on voltages applied to the common electrode 150 and the pixel electrodes 120. It can display three or more colors according to the direction and strength of the electric field generated by the voltage or the application time of the voltage.

The display layer 140 includes a first color solution having a first color and a first density, a second color solution having a second color and a second density, and electrophoretic particles dispersed in the first color solution and the second color solution. may include The first color and the second color may be different from each other, and the second density may be greater than the first density.

The electrophoretic particles may have a color different from the first and second colors. Electrophoretic particles may be charged with a first polarity to move according to the direction of an applied electric field. According to another example, the electrophoretic particles may include first electrophoretic particles charged with a first polarity and second electrophoretic particles charged with a second polarity. In this case, the second polarity may be opposite to the first polarity. According to another example, the second polarity is the same polarity as the first polarity, but the charge amount and/or mass of the first electrophoretic particle may be different from the charge amount and/or mass of the second electrophoretic particle. In this case, the color of the first electrophoretic particles and the color of the second electrophoretic particles may be different from each other.

According to an example, the display layer 140 may include microcapsules each including a first color solution, a second color solution, and electrophoretic particles. The display layer 140 may further include a binder to fix the microcapsules on the common electrode 150 . The display layer 140 including microcapsules will be described in more detail below with reference to FIG. 2 .

According to another example, the display layer 140 may have a mesh-shaped barrier rib formed on the common electrode 150, and the display cells defined or divided by the barrier rib may include a first color solution, a second color solution, and a barrier rib, respectively. Electrophoretic particles may be included. The display layer 140 including display cells defined by barrier ribs will be described in more detail below with reference to FIG. 3 .

The display layer 140 may display three or more colors according to at least one of the direction and intensity of the electric field and the application time of the electric field. A control method for the display layer 140 to display three or more colors will be described in more detail below with reference to FIGS. 4A to 4C.

The common electrode 150 may be disposed over the entire surface of the display layer 140 and positioned between the display layer 140 and the upper substrate 160 . As described above, in the common electrode 150 , a penetration electrode (not shown) penetrating the display layer 140 and the adhesive layer 130 is electrically connected to a connection electrode (not shown) on the lower substrate 110 . When the electrophoretic display device 100 operates, a reference voltage is applied to the common electrode 150 .

According to one example, the through electrode may be formed of a liquid conductive material having a high viscosity. For example, the through electrode may be formed using silver paste, carbon paste, or conductive liquid optically clear adhesive (OCA). According to another example, the through electrode may be formed of a conductive adhesive film. According to another example, the through electrode may be formed of metal.

The common electrode 150 may be formed of a transparent conductive material, for example, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), aluminum zinc oxide (AZO), ZnO, and TCO. (transparent conductive oxide). The common electrode 150 may be entirely formed on the upper substrate 160 through a sputtering process. According to another example, the common electrode 150 may be entirely formed on the upper substrate 160 through a coating process or a plating process.

The upper substrate 160 is disposed on the common electrode 150 and is a light transparent material having high transmittance, and may be a film formed of a material having a high transmittance of 80% or more. For example, the upper substrate 160 is a transparent polymer film having excellent light transmittance, such as polyethersulphone (PES), polyacrylate (PAR), polyetherimide (PEI), or polyethylene naphthalate. (PEN, polyethyelenen napthalate), polyethylene terephthalate (PET, polyethyeleneterepthalate), polyphenylene sulfide (PPS), polyallylate, polyimide, polycarbonate (PC), cellulose triacetate ( TAC), etc., but is not limited thereto.

Although not shown in FIG. 1 , a sealing portion (not shown) may be formed on a side surface of the electrophoretic display device 100 . For example, the sealing part may be disposed to surround at least the outer periphery of the display layer 140 . The sealing portion may function as a main blocking layer that prevents deformation of the display unit 150 from impurities such as oxygen and moisture from the outside.

According to one embodiment, the sealing part may include a photo-curable material that can be cured by irradiating light. The seal may include a mixture of an organic material and a light curable material. The sealing part may be formed by curing by irradiating ultraviolet (UV) light, laser light, visible light, or the like. Examples of the photocurable material included in the sealing part include epoxy acrylate-based resin, polyester acrylate-based resin, urethane acrylate-based resin, and polybutadine acrylate. )-based resins, silicone acrylate-based resins, alkyl acrylate-based resins, and the like. According to another embodiment, the seal may be composed of a frit or the like.

FIG. 2 is a cross-sectional view according to an enlarged example of the display layer of FIG. 1 .

Referring to FIG. 2 , the display layer 140 may include microcapsules 142 , and the microcapsules 142 may be fixed by a binder 141 .

Each of the microcapsules 142 includes a first color solution 145, a second color solution 146, electrophoretic particles 144, and an outer wall 143 of the capsule. The first color solution 145 has a first color and a first density. The second color solution 146 has a second color and a second density. The first color and the second color are different from each other, and the second density is greater than the first density. The electrophoretic particles 144 are dispersed in the first color solution 145 and the second color solution 146 and are charged with a first polarity. As shown in FIG. 2 , the capsule outer wall 143 may surround the first color solution 145 , the second color solution 146 , and the electrophoretic particles 144 .

Although the microcapsules 142 are shown in FIG. 2 as being arranged in a single layer, they may be arranged in multiple layers. In addition, although all of the microcapsules 142 are shown as having the same size, they may have different sizes depending on the manufacturing process. The microcapsules 142 may have a spherical shape with a diameter between approximately several micrometers and several tens of micrometers. The pixel electrode 120 shown in FIG. 1 may have a width between several tens and thousands of micrometers depending on the design. Tens or more microcapsules 142 may be disposed on one pixel electrode 120 .

The electrophoretic particles 144 are dispersed in the first color solution 145 and the second color solution 146 . The electrophoretic particles 144 may be charged with a first polarity (eg, (+) polarity or (-) polarity) so as to move according to the direction of the applied electric field. The electrophoretic particles 144 may absorb light or scatter light.

Electrophoretic particles 144 may include organic or inorganic compounds. Electrophoretic particles 144 may include a reflective material such as metal particles. The electrophoretic particle 144 may be a particle processed (eg, coated) with a color developing material having a unique color such as dye or pigment. For example, the electrophoretic particles 144 include iron (Fe), nickel (Ni), cobalt (Co), titanium (Ti), carbon (C), zinc (Zn), sulfur (S), gold (Au) , silver (Ag), barium (Ba), strontium (Sr), lead (Pb), aluminum (Al), tungsten (W), molybdenum (Mo), and other elements or materials containing their oxides. can include In addition, the electrophoretic particle 144 may be a particle whose surface is processed by a dye or pigment, a particle whose surface is processed by an organic compound, a particle whose surface is processed by a complex compound, a particle whose surface is processed by a coordination compound, and the like. there is.

The electrophoretic particles 144 may have a color different from the first color of the first color solution 145 and the second color of the second color solution 146, for example, white, black, red, blue, or It can be selected from a variety of colors, such as yellow. For example, the color of the electrophoretic particles 144 may be white. The white electrophoretic particles 144 include a method of surface treatment of titanium dioxide particles to have electric charge, a surface treatment method of giving electric charge in a non-polar medium, a method of coating organic/inorganic silane having a large electric capacity difference, and a polar component. It can be produced using at least one of a method of polymerizing a polymeric material containing a polymer on the surface of an inorganic particle and a method of depositing a polar inorganic material.

According to another embodiment, the electrophoretic particles 144 may include first electrophoretic particles charged with a first polarity and second electrophoretic particles charged with a second polarity. The first electrophoretic particles and the second electrophoretic particles may have different colors. In this case, according to an example, the second polarity may be a polarity opposite to the first polarity. According to another example, the second polarity and the first polarity may be the same polarity. In this case, the first electrophoretic particles and the second electrophoretic particles may have different physical and chemical properties such as surface charge, mass, and shape. For example, the first electrophoretic particles may be white and the second electrophoretic particles may be black. The black second electrophoretic particles may be generated using organic/inorganic particles such as carbon black, iron oxide nanoparticles, and copper chromite.

The first color solution 145 and the second color solution 146 include a solvent that allows the electrophoretic particles 144 to disperse and flow, and includes water, methanol, and ethanol. , Propanol, Butanol, Propylene carbonate, Toluene, Benzene, Hexane, Chloroform, Isoparaffin oil, Silicone oil, Esters It may contain materials such as triethylhexanoin, dimethicone, cetyl otanoate, dicaprylate, isopropyl myristate, and tocophenol acetate.

The first color solution 145 and the second color solution 146 may include a fluorescent material, a phosphorescent material, or a light emitting material differently from each other or a color variable material whose color characteristics change as energy is applied (eg, Zion). pigment materials, Zion dye materials, etc.) may be included differently.

For example, the first color solution 145 and the second color solution 146 may include different dye materials such as azo dyes, anthraquinone dyes, carbonium dyes, indigo dyes, sulfur dyes, and phthalocyanine dyes. .

In addition, the first color solution 145 and the second color solution 146 are titanium dioxide, zinc oxide, lithopon, zinc sulfonate, carbon black ), inorganic pigments such as graphite, chrome yellow, fluorescent pigments and pearl pigments, or insoluble azo, soluble azo, phthalocyanine, quinacridone, dioxazine, isoindolinone, vat dyes , Pigment materials including organic pigments such as phyllocolin-based, fluorine-based, quinophthalone-based, and metal complexes may be included differently from each other.

The first color solution 145 has a first color and a first density, and the second color solution 146 has a second color and a second density greater than the first density. The first color and the second color are different colors and may be selected from among red, green, and blue. As another example, the first color and the second color may be selected from among cyan, magenta, and yellow.

The first color solution 145 may include a first solvent and a first dye dissolved in the first solvent. The second color solution 146 may include a second solvent and a second dye dissolved in the second solvent. The first dye may be selected as a material that allows the first color solution 145 to have a first color, and the second dye may be selected as a material that allows the second color solution 146 to have a second color.

The first color solution 145 and the second color solution 146 may be phase separated from each other. The first solvent of the first color solution 145 and the second solvent of the second color solution 146 may be selected so as not to mix with each other. Also, the first dye of the first color solution 145 may be selected from a material insoluble in the second solvent of the second color solution 146 .

The second dye of the second color solution 146 may be selected from a material insoluble in the first solvent of the first color solution 145 . Accordingly, the first color of the first color solution 145 and the second color of the second color solution 146 may not be mixed.

According to another example, the dissolution parameter of the first color solution 145 and the dissolution parameter of the second color solution 146 may be so far apart that the same dye does not dissolve. For example, a first dye matching a first dissolution parameter (eg, 10) of the first solvent is dissolved in the first solvent to form the first color solution 145 . The second color solution 146 is also formed by dissolving a second dye matching a second solubility parameter (eg, 20) of the second solvent in a second solvent. Since the solubility parameters of the first dye and the second dye will also be different, the first dye can be soluble only in the first solvent and the second dye only soluble in the second solvent. Accordingly, the first color of the first color solution 145 and the second color of the second color solution 146 may not be mixed.

As shown in FIG. 2 due to a density difference between the first color solution 145 and the second color solution 146 , the first color solution 145 may be positioned above the second color solution 146 . Since the first color solution 145 and the second color solution 146 are separated from each other without mixing, the first color solution 145 is located on top of the second color solution 146 due to the difference in density where gravity acts. do. To this end, the first solvent and the second solvent may be selected from materials having a density difference enough to be separated from each other.

For example, Isopar M solvent has a density of 0.79 g/ml at 15°C. A halocarbon oil 0.8 solvent having polychlorotrifluoroethylene as a component has a density of 1.71 g/ml at 37.8°C. The SC-PAR solvent having 1,2-dichloropropane as a component has a density of 1.16 g/ml at 20°C. The SC-PAR solvent, which is a mixture of nitroethane, 1-nitropropane, and 2-nitropropane, has a density of 1.01 g/ml at 20°C.

The first solvent of the first color solution 145 and the second solvent of the second color solution 146 may be selected from solvents having a density difference as described above.

The first color solution 145, the second color solution 146, and the electrophoretic particles 144 may be mixed to form an emulsion. The diameter of the emulsion may be 1 μm or more and 1000 μm or less, which may be additionally added to the mixing ratio between the first color solution 145, the second color solution 146 and the electrophoretic particles 144, the stirring speed, It can be adjusted according to factors such as the amount of surfactant present.

The emulsion thus formed may be encapsulated. The capsule outer wall 143 may surround an emulsion in which the first color solution 145 , the second color solution 146 , and the electrophoretic particles 144 are mixed.

A surfactant may be included in the emulsion, and after the first color solution 145 and the second color solution 146 are separated within the outer wall 143 of the capsule, a stable state may be maintained by the surfactant. The surfactant may be any one of anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, and zwitterionic surfactants. The surfactant may be contained in an amount of 0.01% by weight or more and 10% by weight or less based on the total weight of the emulsion.

The capsule outer wall 143 surrounding the emulsion may be made of a light-transmitting polymer material, for example, aginate, gelatin, ethyl cellulose, polyamide, melamine-formaldehyde (melamine formaldehyde), poly(vinyl pyridine), polystyrene, urethane, polyurethane, and methylmethacrylate.

According to one example, the capsule outer wall 143 may be formed by, for example, an in-situ polymerization method. As the molecular weight of monomers dissolved in the aqueous phase increases, oligomers or polymers settle at the interface between the emulsified organic phase and the aqueous solution, and the polymers located at the interface have a larger molecular weight through a crosslinking reaction, resulting in the outer wall of the capsule ( 143)

According to another example, the capsule outer wall 143 may be formed using an isoelectric point by a coacervation microencapsulation method. It is not limited thereto, and the capsule outer wall 143 may be formed by methods such as emulsion polymerization, multiple emulsion polymerization, condensation polymerization, solvent extraction and evaporation, suspension crosslinking, coacer, extrusion, and spraying. there is.

The outer wall 143 of the capsule may be hardened under a high temperature condition, a low temperature condition, an ionic condition, or the like, and may have soft or hard characteristics depending on the concentration or type of the polymer included in the capsule.

After the capsule outer wall 143 is formed, as time passes, the emulsion in the capsule outer wall 143 is separated according to the characteristics and densities of the first color solution 145 and the second color solution 146 . As a result, as shown in FIG. 2 , the first color solution 145 is located in the upper region of the outer wall 143 of the capsule, the second color solution 146 is located in the lower region, and the electrophoretic particles 144 ) may be dispersed in the first color solution 145 and the second color solution 146 and move by the applied electric field.

The electrophoretic particles 144 may move from the first color solution 145 into the second color solution 146 or vice versa by the applied electric field, and the first color solution 145 and the second color solution ( 146) may be located on the border between

The binder 141 may include a material that is at least partially transparent in a visible light region of 380 nm to 750 nm. The binder 141 may include at least one transparent polymer material selected from the group consisting of acrylic polymers, silicone polymers, ester polymers, urethane polymers, amide polymers, ether polymers, fluorine polymers, and rubbers. In addition, the binder 141 may include a fluorescent material, a phosphorescent material, a light emitting material, or a material whose color characteristics change as energy is applied (eg, a Zion pigment material, a Zion dye material, etc.). The binder 141 may be in a cured state.

3 is a cross-sectional view according to another example in which the display layer of FIG. 1 is enlarged.

Referring to FIG. 3 , the display layer 140a includes a barrier rib 143a and display cells 142a defined by the barrier rib 143a. Like the display layer 140 shown in FIG. 1 , the display layer 140a is disposed between the common electrode 150 and the adhesive layer 130 .

Partition walls 143a may be disposed on the common electrode 150 to physically partition the display cells 142a. The barrier ribs 143a may be arranged in a mesh shape or grid shape on a plane.

The barrier rib 143a may be formed of a resin such as an organic compound, an inorganic compound, or a combination thereof. For example, the barrier rib 143a may be formed of a sealing material, for example, a UV curable acrylic resin or a heat curable epoxy resin. The barrier rib 143a may be formed by a stamper method in which a resin layer is formed and then the resin layer is imprinted.

According to another example, the barrier rib 143a may be formed using a photolithographic process. For example, after the photosensitive resin layer is applied on the common electrode 150, light is radiated to the position where the barrier rib 143a is to be formed or to the position to be removed for the formation of the barrier rib 143a using a photo mask, and then development The barrier rib 143a may be formed through the process.

The electrophoretic particles 144a, the first color solution 145a, and the second color solution 146a may be injected into the space partitioned by the barrier rib 143a. The electrophoretic particles 144a, the first color solution 145a, and the second color solution 146a injected into the space defined by the barrier rib 143a may constitute one display cell 142a. The electrophoretic particles 144a, the first color solution 145a, and the second color solution 146a are the electrophoretic particles 144, the first color solution 145, and the Each may correspond to the second color solution 146, and will not be repeatedly described.

An emulsion in which the electrophoretic particles 144a, the first color solution 145a, and the second color solution 146a are mixed may be injected into the space formed by the barrier rib 143a. is separated according to the characteristics and densities of the first color solution 145a and the second color solution 146a, the first color solution 145a is located at the top, the second color solution 146a is located at the bottom, and Migrating particles 144a may be dispersed in the first color solution 145a and the second color solution 146a.

The first color solution 145a and the second color solution 146a may also be phase-separated from each other within the barrier rib 143, and the first color solution 145a is phase-separated from the second color solution 146a due to a density difference. can be located The electrophoretic particles 144a may be located on top of the first color solution 145a or between the first color solution 145a and the second color solution according to the direction and strength of the applied electric field and the time during which the electric field is applied. 146a) or below the second color solution 146a.

4A to 4C are schematic cross-sectional views for explaining the operation of the display layer of FIG. 2 .

Referring to FIG. 4A , a microcapsule 142 is positioned between the pixel electrode 120 and the common electrode 150 . For example, the common electrode 150 may be grounded, and a driving voltage for changing a state of the display layer 140 may be applied to the pixel electrode 120 . Since the display layer 140 includes microcapsules 142, representatively only one microcapsule 142 is shown. It will be understood that the microcapsules 142 positioned around the illustrated microcapsule 142 will operate in the same way if the same electric field is applied. As described above, the microcapsule 142 includes a capsule outer wall 143 , electrophoretic particles 144 , a first color solution 145 and a second color solution 146 .

A phenomenon in which electrophoretic particles in a solution move by an electric field will be described first.

In a state where an electric field (E) is applied, charged electrophoretic particles in the solution move in the solution at a speed (v) proportional to the applied electric field (E) as shown in Equation 1 below.

[Equation 1]

v = µE

Here, μ is a proportionality constant and means electrophoretic mobility. The electrophoretic mobility (μ) can be expressed as in Equation 2 below.

[Equation 2]

μ = ζε/η

Here, ε is the dielectric constant of the solution, η is the viscosity of the solution, and ζ is the zeta potential of the solution. The zeta potential means an electrostatic potential in a shear plane surrounding charged electrophoretic particles, and can be expressed as in Equation 3 below.

[Equation 3]

ζ= gλ _D /ε

Here, g is the charge amount of the electrophoretic particle, and λ _D is the debye length occupied by the electrophoretic particle in the solution. Therefore, when the cell height is h, the switching time (t _total ) of the electrophoretic particles moving at the speed (v) can be quantified by Equation 4 below. Here, V is the applied voltage, and the electric field (E) is equal to V/h.

[Equation 4]

t _total h/v= h/μE= h ² /μV

That is, when the voltage of V is applied for the switching time (t _total ), the electrophoretic particles move as much as the cell height (h) in the solution, so the display color of the display layer is completely changed. If the voltage of V is applied for 1/2 (t _total /2) of the switching time, the electrophoretic particles move by half (h/2) of the height of the cell in the solution. In addition, when a voltage of V/2 is applied for a switching time (t _total ), the electrophoretic particles move by half (h/2) of the height of the cell in the solution.

It is assumed that the electrophoretic particles 144 are negatively charged. When negative high voltage (-HV) is applied to the pixel electrode 120, the electrophoretic particles 144 receive a repulsive force from the pixel electrode 120 and move toward the common electrode 150, and the first color solution (145). Since the electrophoretic particles 144 have bistability, even if the application of the negative high voltage (-HV) to the pixel electrode 120 is stopped, the electrophoretic particles 144 remain in their positions on the first color solution 145. can keep

In this case, since light incident from the top of the common electrode 150 is reflected from the electrophoretic particles 144, an observer sees the color of the electrophoretic particles 144. That is, when a negative high voltage (-HV) is applied to the pixel electrode 120, the display layer 140 displays the color of the electrophoretic particles 144.

The negative high voltage (-HV) is the electrophoretic mobility (μ) of the electrophoretic particles 144 in the first and second color solutions 145 and 146, the voltage application time, the microcapsule 142 It can be set according to the height of

Referring to FIG. 4B , when a positive voltage (+mV) is applied to the pixel electrode 120, the electrophoretic particles 144 receive an attractive force from the pixel electrode 120 and move toward the pixel electrode 120. do. When the magnitude of the positive voltage (+mV) is smaller than the positive high voltage (+HV), the electrophoretic particles 144 are separated from the first color solution 145 according to the application time of the positive voltage (+mV). It is located between the two color solutions (146). Since the electrophoretic particles 144 have bistability, even if the application of the positive voltage (+mV) to the pixel electrode 120 is stopped, the electrophoretic particles 144 form the first color solution 145 and the second color solution 145. The position between the solution 146 may be maintained as it is. According to another example, negative and positive pulse voltages are alternately applied to the pixel electrode 120 so that the electrophoretic particles 144 maintain a position between the first color solution 145 and the second color solution 146. It can be.

When the electrophoretic particles 144 are positioned under the second color solution 146, when a negative voltage (-mV) is applied to the pixel electrode 120, the electrophoretic particles 144 move to the common electrode ( 150) to be positioned between the first color solution 145 and the second color solution 146.

The positive voltage (+mV) is the first electrophoretic mobility (μ1) of the electrophoretic particles 144 in the first color solution 145, the voltage application time, and the height of the first color solution 145. can be set according to In addition, the negative voltage (-mV) is the second electrophoretic mobility of the electrophoretic particles 144 in the second color solution 146 (μ2), the voltage application time, the second color solution 146 It can be set according to the height of

In this case, since light incident from the top of the common electrode 150 passes through the first color solution 145 and is reflected from the electrophoretic particles 144, an observer looking at the microcapsule 142 can see the first color solution A mixed color of the first color of 145 and the color of the electrophoretic particles 144 is seen. For example, when the color of the electrophoretic particles 144 is white, an observer sees the first color of the first color solution 145 . That is, when a positive voltage (+mV) is applied to the pixel electrode 120, the display layer 140 displays the first color of the first color solution 145.

Referring to FIG. 4C , when a positive high voltage (+HV) is applied to the pixel electrode 120, the electrophoretic particles 144 receive an attractive force from the pixel electrode 120 and move toward the pixel electrode 120. and is located under the second color solution 146. Since the electrophoretic particles 144 have bistability, even if the positive high voltage (+HV) is not applied to the pixel electrode 120, the electrophoretic particles 144 maintain a position under the second color solution 146. can be kept as is.

In this case, since the light incident from the top of the common electrode 150 passes through the first and second color solutions 145 and 146 and is reflected from the electrophoretic particles 144, the observer can see the first and second color solutions. The mixed color of the first and second colors of (145, 146) and the color of the electrophoretic particles 144 is seen. For example, when the color of the electrophoretic particles 144 is white, an observer watching the microcapsule 142 has a first color of the first color solution 145 and a second color of the second color solution 146. You will see mixed colors. For example, when the first color is yellow and the second color is magenta, a color obtained by mixing the first color and the second color is red, and an observer sees red. That is, when a positive high voltage (+HV) is applied to the pixel electrode 120, the display layer 140 displays a new color obtained by mixing the first color and the second color.

The positive high voltage (+HV) is the electrophoretic mobility (μ) of the electrophoretic particles 144 in the first and second color solutions 145 and 146, the voltage application time, the microcapsule 142 It can be set according to the height of

For example, it is assumed that the color of the electrophoretic particles 144 is white, and the first and second colors are yellow and magenta, respectively. When a negative high voltage (-HV) is applied to the pixel electrode 120, the display layer 140 displays white, which is the color of the electrophoretic particles 144.

A positive voltage (+mV) is applied to the pixel electrode 120 in a state where the electrophoretic particles 144 are positioned on the first color solution 145, or the electrophoretic particles 144 are placed on the second color solution ( 146) When a negative voltage (-mV) is applied to the pixel electrode 120 in a state located below, the display layer 140 displays yellow, which is the first color of the first color solution 145. When a negative high voltage (-HV) is applied to the pixel electrode 120, the display layer 140 displays red, which is a color obtained by mixing the first color and the second color.

Therefore, as shown in FIGS. 4A to 4C , the display layer 140 can display three colors depending on the voltage applied to the pixel electrode 120 and the application time.

Meanwhile, the electrophoretic particles 144 may be located in the first color solution 145 or the second color solution 146 according to the voltage and/or application time applied to the pixel electrode 120 . For example, when the electrophoretic particles 144 are positioned above the first color solution 145, a voltage smaller than the voltage (+mv) applied to the pixel electrode 120 in the embodiment of FIG. 4B is It may be applied or the application time may be shorter. The electrophoretic particles 144 do not reach the boundary between the first and second color solutions 145 and 146 from the top of the first color solution 145 and are located in the middle of the first color solution 145. . At this time, the display layer 140 displays a color that is lighter than the color of the first color solution 145 . By adjusting the voltage and/or the application time applied to the pixel electrode 120 as described above, the brightness of the color displayed by the display layer 140 can be adjusted.

Although the operation of the display layer 140 of FIG. 2 has been described with reference to FIGS. 4A to 4C, those skilled in the art will understand the principle of operation of the display layer 140 of FIG. 3 as well as the display layer 140a of FIG. It will be understood that it can operate on the same principle as

Figure 5a is a cross-sectional view according to another example of the microcapsule shown in Figure 2.

Referring to FIG. 5A, the microcapsule 142b includes a first color solution 145b, a second color solution 146b, a third color solution 147b, electrophoretic particles 144b, and a capsule outer wall 143b. include The microcapsules 142b may be included in the display layer 140 of FIG. 1 like the microcapsules 142 of FIG. 2 . The microcapsule 142b corresponds to the microcapsule 142 of FIG. 2, and the differences are mainly described below, and the description of the microcapsule 142 is for the microcapsule 142b unless otherwise specified. Used as an explanation.

The electrophoretic particles 144b and the capsule outer wall 143b are substantially the same as the electrophoretic particles 144 and the capsule outer wall 143 shown in FIG. 3 and will not be repeatedly described. In addition, the first color solution 145b and the second color solution 146b correspond to the first color solution 145 and the second color solution 146 shown in FIG. 3, and the differences will be mainly described below. .

The first color solution 145b has a first color and a first density. The second color solution 146b has a second color and a second density. The third color solution 147b has a third color and a third density. All of the first to third colors are different from each other. For example, the first to third colors may constitute three primary colors. For example, the first to third colors may be selected differently from each other among red, green, and blue. As another example, the first to third colors may be selected differently from each other among cyan, magenta, and yellow. The electrophoretic particles 144b may have a color different from the first to third colors, and may be, for example, white.

The second density is greater than the first density, and the third density is greater than the second density. The first to third color solutions 145b, 146b, and 147b may be phase-separated from each other according to their respective chemical properties. As shown in FIG. 5A due to the difference in density between the first to third color solutions 145b, 146b, and 147b, the first color solution 145b is positioned on top of the second color solution 146b, and the second color solution 146b The solution 146b may be positioned on top of the third color solution 147b.

The first to third color solutions 145b, 146b, and 147b include a solvent that allows the electrophoretic particles 144b to disperse and flow. The first color solution 145b may include a first solvent and a first dye dissolved in the first solvent. The second color solution 146b may include a second solvent and a second dye dissolved in the second solvent. The third color solution 147b may include a third solvent and a third dye dissolved in the third solvent.

Since the first to third color solutions 145b, 146b, and 147b are separated from each other without being mixed, the first to third color solutions 145b, 146b, and 147b are stacked on each other due to the density difference where gravity acts. Located. To this end, the first to third solvents may be selected from materials having a density difference sufficient to be separated from each other.

The first dye is selected as a material that allows the first color solution 145b to have a first color, the second dye is selected as a material that allows the second color solution 146b to have a second color, and the third dye is A material that gives the third color solution 147b a third color may be selected.

As described above, the first to third color solutions 145b, 146b, and 147b may be phase separated from each other. The first to third solvents of the first to third color solutions 145b, 146b, and 147b may be selected so as not to mix with each other. In addition, to prevent the first to third colors of the first to third color solutions 145b, 146b, and 147b from mixing with each other, the first dye of the first color solution 145b is applied to the second color solution 146b. A material insoluble in the second solvent and the third solvent of the third color solution 147b is selected, and the second dye of the second color solution 146b is insoluble in the first solvent and the third solvent of the first color solution 145b. A material insoluble in the third solvent of the color solution 147b is selected, and the third dye of the third color solution 147b is a combination of the first solvent of the first color solution 145b and the second color solution 146b. A material insoluble in the second solvent may be selected.

According to another example, dissolution parameters of the first to third color solutions 145b, 146b, and 147b may be so far apart that the same dye is not dissolved in two or more solvents. For example, a first dye matching a first dissolution parameter (eg, 10) of the first solvent is dissolved in the first solvent to form the first color solution 145b. The second color solution 146b is also formed by dissolving a second dye matching a second solubility parameter (eg, 20) of the second solvent in a second solvent. In addition, the third color solution 147b is also formed by dissolving a third dye matching a third dissolution parameter (eg, 30) of the third solvent in the third solvent. In this case, since the dissolution parameters of the first to third dyes will also be different from each other, the first dye can dissolve only in the first solvent, the second dye can only dissolve in the second solvent, and the third dye can only dissolve in the third solvent. there is. Accordingly, the first to third colors of the first to third color solutions 145b, 146b, and 147b may not be mixed with each other.

For example, the first to third color solutions 145b, 146b, and 147b may contain different dye materials such as azo dyes, anthraquinone dyes, carbonium dyes, indigo dyes, sulfur dyes, and phthalocyanine dyes. .

The first to third color solutions 145b, 146b, and 147b may include different pigment materials including inorganic pigments or organic pigments. The first to third color solutions 145b, 146b, and 147b may include a fluorescent material, a phosphorescent material, or a light emitting material differently from each other. In addition, the first to third color solutions 145b, 146b, and 147b may include different color variable materials (eg, Zion pigment material, Zion dye material, etc.) whose color characteristics change as energy is applied. there is.

The first to third color solutions 145b, 146b, and 147b and the electrophoretic particles 144b are mixed to form an emulsion, and the emulsion may be encapsulated. The capsule outer wall 143b formed by encapsulation may surround the emulsion in which the first to third color solutions 145b, 146b, and 147b and the electrophoretic particles 144b are mixed. Emulsions may contain surfactants.

After the capsule outer wall 143 is formed, as time passes, the emulsions in the capsule outer wall 143 separate from each other as shown in FIG. do.

FIG. 5B is a cross-sectional view of another example of the display cell shown in FIG. 3 .

Referring to FIG. 5B , a display cell 142c is shown bounded by partition walls 143c. The display cell 142c includes first to third color solutions 145c, 146c, and 147c and electrophoretic particles 144c. The display cell 142c and the barrier rib 143c defining the display cell 142c may be included in the display layer 140 of FIG. 1 . The barrier rib 143c is substantially the same as the barrier rib 143a shown in FIG. 3 , and the electrophoretic particles 144c are substantially the same as the electrophoretic particles 144a shown in FIG. 3 . The same components are not repeatedly described.

The electrophoretic particles 144c and the first to third color solutions 145c, 146c, and 147c may be injected into the space partitioned by the barrier rib 143c. The first to third color solutions 145c, 146c, and 147c may respectively correspond to the first to third color solutions 145b, 146b, and 147b described above with reference to FIG. 5A, and are repeated for these. don't explain

An emulsion in which the electrophoretic particles 144c, the first color solution 145c, and the second color solution 146c are mixed may be injected into the space formed by the barrier rib 143c. The emulsion may be separated according to the characteristics and densities of the first to third color solutions 145c, 146c, and 147c, and may be separated from each other as shown in FIG. 5B. Electrophoretic particles 144c may be dispersed in the first to third color solutions 145c, 146c, and 147c.

6A to 6D are schematic cross-sectional views for explaining the operation of the display layer including the microcapsules of FIG. 5A.

Referring to FIG. 6A , microcapsules 142b in the display layer 140 are positioned between the pixel electrode 120 and the common electrode 150 . The common electrode 150 may be grounded, and a driving voltage for changing a state of the display layer 140 may be applied to the pixel electrode 120 .

It is assumed that the electrophoretic particles 144 are negatively charged. When negative high voltage (-HV) is applied to the pixel electrode 120, the electrophoretic particles 144 receive a repulsive force from the pixel electrode 120 and move toward the common electrode 150, and the first color solution It is located on (145b). Since the electrophoretic particles 144b have bistability, even if the application of the negative high voltage (-HV) to the pixel electrode 120 is stopped, the electrophoretic particles 144 remain in their positions on the first color solution 145b. can keep

In this case, since light incident from the top of the common electrode 150 is reflected from the electrophoretic particles 144b, an observer sees the color of the electrophoretic particles 144b. That is, when a negative high voltage (-HV) is applied to the pixel electrode 120, the display layer 140 displays the color of the electrophoretic particles 144b. Below, it is assumed that the color of the electrophoretic particles 144b is white.

The negative high voltage (-HV) is the electrophoretic mobility (μ) of the electrophoretic particles 144 in the first and second color solutions 145 and 146, the voltage application time, the microcapsule 142 It can be set according to the height of

Referring to FIG. 6B , when a positive voltage (+mV) is applied to the pixel electrode 120, the electrophoretic particles 144b are positioned between the first color solution 145b and the second color solution 146b. can do. The magnitude of the positive voltage (+mV) may be smaller than that of the positive high voltage (+HV).

In order for the electrophoretic particles 144b to be located between the first color solution 145b and the second color solution 146b, the magnitude of the voltage applied to the pixel electrode 120 and the voltage application time depend on the electrophoretic particles 144b ) may vary depending on the previous position.

Since the light incident from the top of the common electrode 150 passes through the first color solution 145b and is reflected from the electrophoretic particles 144b, an observer looking at the microcapsule 142b can see the first color solution 145 You will see the first color of That is, when a positive voltage (+mV) is applied to the pixel electrode 120, the display layer 140 displays the first color of the first color solution 145c.

Referring to FIG. 6C , when a negative voltage (-mV) is applied to the pixel electrode 120, the electrophoretic particles 144b are positioned between the second color solution 146b and the third color solution 147b. can do. The magnitude of the negative voltage (-mV) may be smaller than that of the negative high voltage (-HV).

In order for the electrophoretic particles 144b to be located between the second color solution 146b and the third color solution 147b, the magnitude of the voltage applied to the pixel electrode 120 and the voltage application time depend on the electrophoretic particles 144b ) may vary depending on the previous position.

Since the light incident from the top of the common electrode 150 passes through the first color solution 145b and the second color solution 146b and is reflected from the electrophoretic particles 144b, an observer watching the microcapsule 142b sees a color in which the first color of the first color solution 145b and the second color of the second color solution 146b are mixed. That is, when a negative voltage (-mV) is applied to the pixel electrode 120, the display layer 140 displays a color in which the first color and the second color are mixed. For example, when the first color is yellow and the second color is magenta, the mixed color of the first color and the second color may be red.

Referring to FIG. 6D , when a positive high voltage (+HV) is applied to the pixel electrode 120, the electrophoretic particles 144b are located under the third color solution 147b.

In this case, light incident from the top of the common electrode 150 passes through the first to third color solutions 145b, 146b, and 147b and is reflected from the electrophoretic particles 144b. A mixed color of the first to third colors of the three color solutions 145b, 146b, and 147b is seen. When the first to third colors constitute the three primary colors, the microcapsule 142b may display black.

The positive high voltage (+HV) is the electrophoretic mobility (μ) of the electrophoretic particles 144b in the first to third color solutions 145b, 146b, and 147b, the voltage application time, the microcapsule ( 142b) can be set according to the height.

Accordingly, as shown in FIGS. 6A to 6D , the display layer 140 including the microcapsules 142b may display at least four colors depending on the voltage applied to the pixel electrode 120 and the application time.

Although the operation of the microcapsule 142b of FIG. 5a has been described with reference to FIGS. 6A to 6D, those skilled in the art can also use the display layer 140 including the display cell 142c of FIG. 5B as a microcapsule ( It will be understood that it can operate on the same principle as the operating principle of 142b).

If the order of each step constituting the manufacturing method according to the present invention is explicitly described or does not contradict, each step can be performed in an appropriate order. The present invention is not limited to being performed according to the described order of each step. The use of all examples or exemplary terms (eg, etc.) in the present invention is solely for the purpose of explaining the present invention in detail, and the use of the above examples or exemplary terminology will obscure the scope of the present invention unless it is limited by the claims. The scope is not limited. In addition, those skilled in the art may know that design conditions and factors may be modified within the scope of the claims or equivalents thereof.

Therefore, the spirit of the present invention should not be limited to the above-described embodiments, and not only the claims to be described later, but also all scopes equivalent to or equivalently changed from these claims fall within the scope of the spirit of the present invention. would be considered to be in the category.

100: electrophoretic display device 110: lower substrate
120: pixel electrode 130: adhesive layer
140: display layer 150: common electrode
160: upper substrate 141: binder
142: microcapsule 143: capsule outer wall
144: electrophoretic particles 145: first color solution
146: second color solution

Claims (20)

a plurality of pixel electrodes;
common electrode; and
A display layer including display cells arranged between the pixel electrodes and the common electrode;
Each of the display cells,
a first color solution having a first color and having a first density;
a second color solution having a second color different from the first color and having a second density greater than the first density; and
An electrophoretic display device comprising electrophoretic particles dispersed in the first color solution and the second color solution and charged with a first polarity. According to claim 1,
The electrophoretic display device, characterized in that the first color solution and the second color solution are phase-separated from each other in the display cell. According to claim 1,
The electrophoretic display device, characterized in that the first color solution is located on the second color solution due to a density difference. According to claim 3,
The electrophoretic particles are controlled to be positioned on the first color solution, between the first color solution and the second color solution, or under the second color solution by an electric field between the pixel electrodes and a common electrode. Electrophoretic display device, characterized in that being. According to claim 4,
When the electrophoretic particles are white,
Displaying the first color of the first color solution when the electrophoretic particles are positioned between the first color solution and the second color solution;
When the electrophoretic particles are located under the second color solution, the first color of the first color solution and the second color of the second color solution are mixed to display a third color. Electrophoretic display device. According to claim 1,
The first color solution includes a first solvent and a first dye dissolved in the first solvent,
The electrophoretic display device of claim 1 , wherein the second color solution includes a second solvent and a second dye dissolved in the second solvent. According to claim 6,
The electrophoretic display device, wherein the first dye is insoluble in the second solvent, and the second dye is insoluble in the first solvent. According to claim 1,
wherein each of the display cells includes a microcapsule having a capsule outer wall surrounding the first color solution, the second color solution and the electrophoretic particles. According to claim 1,
The electrophoretic display device according to claim 1 , wherein the display layer includes barrier ribs separating the display cells from each other. a plurality of pixel electrodes;
common electrode; and
A display layer including display cells arranged between the pixel electrodes and the common electrode;
Each of the display cells,
a first color solution having a first color and having a first density;
a second color solution having a second color different from the first color and having a second density greater than the first density;
a third color solution having a third color different from the first and second colors and having a third density greater than the second density; and
An electrophoretic display device comprising electrophoretic particles dispersed in the first to third color solutions and charged with a first polarity. According to claim 10,
The electrophoretic display device, characterized in that the first to third color solutions are phase-separated from each other in the display cell. According to claim 10,
The first color solution is located on the second color solution due to a density difference,
The electrophoretic display device, characterized in that the second color solution is located on the third color solution due to a density difference. According to claim 12,
The electrophoretic particles are formed on the first color solution, between the first color solution and the second color solution, and between the second color solution and the third color solution by an electric field between the pixel electrodes and the common electrode. Electrophoretic display device, characterized in that controlled to be positioned between or below the third color solution. According to claim 13,
When the electrophoretic particles are white,
Displaying the first color when the electrophoretic particles are positioned between the first color solution and the second color solution;
When the electrophoretic particles are positioned between the second color solution and the third color solution, a fourth color obtained by mixing the first color and the second color is displayed;
When the electrophoretic particles are located under the third color solution, the electrophoretic display device of claim 1 , wherein a fifth color in which all of the first to third colors are mixed is displayed. According to claim 10,
The first color solution includes a first solvent and a first dye dissolved in the first solvent,
The second color solution includes a second solvent and a second dye dissolved in the second solvent,
The electrophoretic display device of claim 1 , wherein the third color solution includes a third solvent and a third dye dissolved in the third solvent. According to claim 15,
The first dye is insoluble in the second solvent and the third solvent,
The second dye is insoluble in the first solvent and the third solvent,
The electrophoretic display device according to claim 1 , wherein the third dye is insoluble in the first solvent and the second solvent. a first color solution having a first color and having a first density;
a second color solution having a second color different from the first color and having a second density greater than the first density;
electrophoretic particles dispersed in the first color solution and the second color solution and charged with a first polarity; and
A microcapsule for an electrophoretic display device comprising an outer wall of the capsule surrounding the first color solution, the second color solution, and the electrophoretic particles. According to claim 17,
The first and second color solutions are phase separated from each other in the display cell,
The first color solution is a microcapsule for an electrophoretic display device, characterized in that located on the second color solution by the difference in density. According to claim 17,
The first color solution includes a first solvent and a first dye dissolved in the first solvent and having the first color;
The second color solution includes a second solvent and a second dye dissolved in the second solvent and having the second color;
wherein the first dye is insoluble in the second solvent, and the second dye is insoluble in the first solvent. According to claim 17,
A microcapsule for an electrophoretic display device further comprising a third color solution having a third color different from the first and second colors and having a third density greater than the second density.

Images