JP2005070462A - Method of manufacturing electrophoretic display device, electrophoretic display device and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an electrophoretic display device by which the electrophoretic display device having excellent display performance and uniform characteristics can be manufactured, to provide the electrophoretic display device manufactured by the same method and to provide an electronic device having high reliability. <P>SOLUTION: The method of manufacturing the electrophoretic display device has: a first step for supplying a microcapsule dispersion liquid containing microcapsules 40 in which electrophoretic dispersion liquid 10 containing at least one kind of electrophoretic particles 5 is encapsulated, a water soluble setting resin precursor and an aqueous solvent onto a second substrate 2 provided with a second electrode 4; a second step for removing at least a portion of the aqueous solvent; and a third step for joining a first substrate 1 and the second substrate 2 by curing the setting resin precursor by a polymerization reaction while the first substrate (counter substrate) 1 provided with a first electrode 3 is opposed to the second substrate 2 (the second electrode 4) via the microcapsules 40. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrophoretic display device manufacturing method, an electrophoretic display device, and an electronic apparatus.

Generally, it is known that when an electric field is applied to a dispersion system in which fine particles are dispersed in a liquid, the fine particles move (migrate) in the liquid by Coulomb force. This phenomenon is called electrophoresis. In recent years, an electrophoretic display device that displays desired information (image) using this electrophoresis has attracted attention as a new display device.
This electrophoretic display device has characteristics such as a display memory property and a wide viewing angle property in a state where voltage application is stopped, and a high-contrast display with low power consumption.

In addition, since the electrophoretic display device is a non-light-emitting device, the electrophoretic display device has a feature that it is easier on the eyes than a light-emitting display device such as a cathode ray tube.
As such an electrophoretic display device, a plurality of microcapsules enclosing electrophoretic particles and a liquid phase dispersion medium are disposed between a pair of substrates having electrodes, and a binder material for fixing each substrate and the microcapsules is disposed. A microcapsule type is known.

Here, FIG. 7 schematically shows the operating principle of such an electrophoretic display device.
In such an electrophoretic display device 920, when a voltage is applied between the electrodes 903 and 904 provided on the pair of substrates, the electrophoretic particles 905 in the microcapsule are aligned in the direction of the electric field generated between the electrodes 903 and 904. Accordingly, the liquid phase dispersion medium 906 moves toward one of the electrodes. As a result, the observer can see the color of the electrophoretic particles 905 (see FIG. 7A) and / or the color of the liquid phase dispersion medium 906 (see FIG. 7B).
Therefore, desired information can be displayed by patterning one or both electrodes and controlling the voltage applied to them.

By the way, in this electrophoretic display device, when the pair of substrates and the microcapsules are fixed with a binder material, for example, as described in Patent Document 1.
The oil-soluble (lipophilic) resin particles (polymer particles) that will eventually become the binder material are dispersed in an aqueous solvent as an emulsion, and the microcapsules are dispersed in this dispersion to produce an aqueous emulsion-type microcapsule dispersion. Prepare.

Here, the reason why the aqueous solvent is used as the solvent is that when a hydrophobic solvent is used, the solvent penetrates into the microcapsules and swells and dissolves the microcapsules.
And this microcapsule dispersion liquid is apply | coated to the surface in which the electrode of one board | substrate is formed. Next, after drying this coating film, the other board | substrate is piled up and board | substrates are crimped | bonded.
Accordingly, the pair of substrates and the microcapsules are bonded and fixed by the binder material, and the electrophoretic display device is created.

However, in this type of microcapsule dispersion, an ionic surfactant for dispersing oil-soluble resin particles in an aqueous solvent or an amine-based adhesion reinforcing agent (for example, diethylamine) for improving adhesiveness is used. Addition of ionic additives is required.
These ionic additives pass through the microcapsule and enter the capsule, adversely affect the charged particles, for example, reduce the charge amount, and reduce the display performance of the electrophoretic display device. .
For this reason, an electrophoretic display device manufactured using this water-based emulsion type microcapsule dispersion has problems that it is difficult to control the characteristics and to obtain uniform characteristics.

JP 2003-140198 A

  An object of the present invention is to provide an electrophoretic display device manufacturing method capable of manufacturing an electrophoretic display device having excellent display performance and uniform characteristics, and an electrophoretic display device manufactured by such an electrophoretic display device manufacturing method, Another object is to provide a highly reliable electronic device.

Such an object is achieved by the present invention described below.
The method for producing an electrophoretic display device of the present invention includes a microcapsule in which an electrophoretic dispersion liquid containing at least one type of electrophoretic particles is sealed on a substrate having electrodes, a water-soluble curable resin precursor, A first step of supplying a microcapsule dispersion containing an aqueous solvent;
A second step of removing at least a part of the aqueous solvent;
A third step of bonding the counter substrate and the substrate by curing the curable resin precursor by a polymerization reaction with the counter substrate opposed to the substrate via the microcapsule. It is characterized by that.
Thereby, an electrophoretic display device having excellent display performance and uniform characteristics can be manufactured.

In the method for producing an electrophoretic display device of the present invention, it is preferable that a monomer is contained as the water-soluble curable resin precursor.
Monomers are preferred because of their high solubility in aqueous solvents.
In the method for manufacturing an electrophoretic display device of the present invention, it is preferable that the monomer is oligomerized in the second step or prior to the second step.
Thereby, it can prevent that a water-soluble curable resin precursor dissipates with an aqueous solvent.

In the method for manufacturing an electrophoretic display device of the present invention, it is preferable that an oligomer is included as the water-soluble curable resin precursor.
Thereby, the process of oligomerizing the monomer can be omitted.
In the method for producing an electrophoretic display device of the present invention, the oligomer preferably has a weight average molecular weight of 250 to 1,000.
Thereby, it can prevent more reliably that an oligomer permeate | transmits in a microcapsule and dissipates with an aqueous medium.

In the method for producing an electrophoretic display device of the present invention, it is preferable that the water-soluble curable resin precursor starts a polymerization reaction by heating or light irradiation.
Thereby, the polymerization reaction of a water-soluble curable resin precursor can be advanced without requiring a large-scale installation.
In the method for producing an electrophoretic display device of the present invention, the content of the water-soluble curable resin precursor in the microcapsule dispersion is preferably 0.1 to 20% by weight.
Thereby, joining of substrates and fixing of a microcapsule can be performed more reliably.

In the method for manufacturing an electrophoretic display device of the present invention, in the second step, the aqueous solvent is preferably removed by standing at room temperature or heating.
In the method by standing at room temperature, it is possible to remove the aqueous solvent while preventing the polymerization reaction of the water-soluble curable resin precursor from proceeding more than necessary. On the other hand, in the method using heating, the aqueous solvent is surely and quickly. Can be removed.

In the method for producing an electrophoretic display device of the present invention, it is preferable that the heating in the second step is performed under a condition that the water-soluble curable resin precursor does not completely cure.
Thereby, it can prevent that the viscosity of a film lose | disappears and can join substrates suitably.
In the method for manufacturing an electrophoretic display device of the present invention, it is preferable that in the first step, the microcapsule dispersion liquid is supplied onto the substrate so as to have a thickness substantially equal to the average particle diameter of the microcapsules. .
As a result, the microcapsules can be arranged in a single layer on the substrate.

In the method for producing an electrophoretic display device of the present invention, the average particle diameter of the microcapsules is preferably 20 to 200 μm.
Thereby, an electrophoretic display device with higher display performance can be obtained.
In the method for producing an electrophoretic display device of the present invention, the content of the microcapsules in the microcapsule dispersion is preferably 10 to 70% by weight.
Thereby, an electrophoretic display device with higher display performance can be obtained.

In the method for manufacturing an electrophoretic display device of the present invention, in the third step, the water-soluble curable resin precursor is cured by bringing either the counter substrate or the substrate relatively close to the other. It is preferable to be carried out in the state.
Thereby, joining of substrates and fixing of a microcapsule can be performed more reliably.

An electrophoretic display device of the present invention includes a substrate including an electrode,
A plurality of microcapsules disposed on the substrate and encapsulating an electrophoretic dispersion containing at least one type of electrophoretic particles;
A counter substrate disposed opposite to the substrate via the microcapsule;
An electrophoretic display device having a binder material bonded to the substrate and the counter substrate,
The binder material is obtained by curing a water-soluble curable resin precursor by a polymerization reaction.
Thereby, an electrophoretic display device having excellent display performance and uniform characteristics can be obtained.
An electronic apparatus according to the present invention includes the electrophoretic display device according to the present invention.
As a result, a highly reliable electronic device can be obtained.

Hereinafter, a method for manufacturing an electrophoretic display device, an electrophoretic display device, and an electronic apparatus according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
<First Embodiment>
First, a first embodiment of the electrophoretic display device of the present invention will be described.
FIG. 1 is a longitudinal sectional view showing a first embodiment of the electrophoretic display device of the present invention, and FIG. 2 is a schematic diagram showing the operating principle of the electrophoretic display device shown in FIG.

In the following description, for convenience of explanation, the upper side in FIGS. 1 and 2 (the same applies to the following drawings) is “upper” or “upper”, and the lower side is “lower” or “lower”. "
An electrophoretic display device 20 shown in FIG. 1 includes a first substrate (counter substrate) 1 including a first electrode 3 and a second substrate (substrate) including a second electrode 4 facing the first electrode 3. ) 2, a plurality of microcapsules 40 disposed between the first substrate 1 and the second substrate 2 and encapsulating the electrophoretic dispersion 10, and a binder material 41. Hereinafter, the structure of each part is demonstrated sequentially.

The 1st board | substrate 1 and the 2nd board | substrate 2 are respectively comprised by the sheet-like (flat plate-shaped) member, and have a function which supports and protects each member distribute | arranged among these.
Each of the substrates 1 and 2 may be either flexible or hard, but is preferably flexible. By using the substrates 1 and 2 having flexibility, the electrophoretic display device 20 having flexibility, that is, for example, an electrophoretic display device 20 useful in constructing electronic paper can be obtained.

  When each of the substrates 1 and 2 is flexible, the constituent materials thereof include, for example, polyolefins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymer, modified polyolefins, and polyamides (example: Nylon 6, nylon 46, nylon 66, nylon 610, nylon 612, nylon 11, nylon 12, nylon 6-12, nylon 6-66), thermoplastic polyimide, aromatic polyester and other liquid crystal polymers, polyphenylene oxide, polyphenylene sulfide, Polycarbonate, polymethyl methacrylate, polyether, polyether ether ketone, polyether imide, polyacetal, styrene, polyolefin, polyvinyl chloride, polyurethane, polyester, polyamide, Examples thereof include various types of thermoplastic elastomers such as rebutadiene, trans polyisoprene, fluoro rubber, and chlorinated polyethylene, or copolymers, blends, polymer alloys, etc. mainly composed of these. A seed or a mixture of two or more can be used.

The thickness (average) of the substrates 1 and 2 is appropriately set depending on the constituent material, application, and the like, and is not particularly limited. However, when having flexibility, it is about 20 to 500 μm. Preferably, it is about 25-250 micrometers. As a result, the electrophoretic display device 20 can be reduced in size (particularly thinner) while achieving harmony between the flexibility and strength of the electrophoretic display device 20.
On the surface of the substrates 1 and 2 on the side of the microcapsule 40, that is, on the lower surface of the first substrate 1 and the upper surface of the second substrate 2, respectively, the first electrode 3 and the Two electrodes 4 are provided.

When a voltage is applied between the first electrode 3 and the second electrode 4, an electric field is generated between them, and this electric field acts on the electrophoretic particles 5.
In the present embodiment, the first electrode 3 is a common electrode, and the second electrode 4 is an individual electrode (pixel electrode) divided into a matrix (matrix). A portion where one second electrode 4 overlaps constitutes one pixel. Note that the first electrode 3 may be divided into a plurality of parts in the same manner as the second electrode 4.

The constituent materials of the electrodes 3 and 4 are not particularly limited as long as they are substantially conductive. For example, copper, aluminum, nickel, cobalt, platinum, gold, silver, molybdenum, tantalum, or these Metal materials such as alloys containing carbon, carbon-based materials such as carbon black, carbon nanotubes, fullerenes, polyacetylene, polypyrrole, polythiophene, polyaniline, poly (p-phenylene), poly (p-phenylenevinylene), polyfluorene, polycarbazole, In an electroconductive polymer material such as polysilane or a derivative thereof, or in a matrix resin such as polyvinyl alcohol, polycarbonate, polyethylene oxide, polyvinyl butyral, polyvinyl carbazole, or vinyl acetate, NaCl, LiClO ₄ , KCl, H ₂ O, L iCl, LiBr, LiI, LiNO ₃ , LiSCN, LiCF ₃ SO ₃ , NaBr, NaI, NaSCN, NaClO ₄ , NaCF ₃ SO ₃ , KI, KSCN, KClO ₄ , KCF ₃ SO ₃ , NH ₄ I, NH ₄ SCN, NH ₄ ClO ₄ , NH ₄ CF ₃ SO ₃ , MgCl ₂ , MgBr ₂ , MgI ₂ , Mg (NO ₃ ) ₂ , MgSCN ₂ , Mg (CF ₃ SO ₃ ) ₂ , ZnCl ₂ , ZnI ₂ , ZnSCN ₂ , Zn Ionic conductivity in which ionic substances such as (ClO ₄ ) ₂ , Zn (CF ₃ SO ₃ ) ₂ , CuCl ₂ , CuI ₂ , CuSCN ₂ , Cu (ClO ₄ ) ₂ , Cu (CF ₃ SO ₃ ) ₂ are dispersed. Polymer materials, indium tin oxide (ITO), fluorine-doped tin oxide (FTO), tin oxide (S O _2), various conductive materials include such as a conductive oxide material such as indium oxide (IO), can be used singly or in combination of two or more of them.

In addition, as a constituent material of each electrode 3, 4, for example, a conductive material such as gold, silver, nickel, carbon, etc. in a non-conductive material such as glass material, rubber material, polymer material, etc. Various composite materials in which (conductive particles) are mixed to add conductivity can also be used.
Specific examples of such a composite material include, for example, a conductive rubber in which a conductive material is mixed in a rubber material, a conductive rubber in which an electrically conductive material is mixed in an adhesive composition such as epoxy, urethane, and acrylic. In matrix resin such as conductive adhesive or conductive paste, polyolefin, polyvinyl chloride, polystyrene, ABS resin, nylon (polyamide), ethylene vinyl acetate copolymer, polyester, acrylic resin, epoxy resin, urethane resin Examples thereof include a conductive resin mixed with a conductive material.

The thickness (average) of the electrodes 3 and 4 is appropriately set depending on the constituent material, application, etc., and is not particularly limited, but is preferably about 0.05 to 10 μm, preferably about 0.05 to 5 μm. It is more preferable that
Of the substrates 1 and 2 and the electrodes 3 and 4, the substrate and the electrodes (in the present embodiment, the first substrate 1 and the first electrode 3) disposed on the display surface side are respectively light transmissive. That is, it is preferably substantially transparent (colorless transparent, colored transparent or translucent). Thereby, the state of the electrophoretic particles 5 in the electrophoretic dispersion liquid 10 described later, that is, the information (image) displayed on the electrophoretic display device 20 can be easily recognized visually.

Each of the electrodes 3 and 4 may have a multilayer structure in which a plurality of materials are sequentially stacked, for example, in addition to a single layer structure made of a single material as described above. That is, each of the electrodes 3 and 4 may have a single layer structure made of ITO, for example, or may have a two-layer structure of an ITO layer and a polyaniline layer.
In addition, the function of defining the distance between the first electrode 3 and the second electrode 4 between the first substrate 1 and the second substrate 2 in the vicinity of the side portion of the electrophoretic display device 20. A spacer 70 is provided.

In this embodiment, the spacer 70 is provided so as to surround the outer periphery of the electrophoretic display device 20, and a sealed space 71 is defined (formed) between the first substrate 1 and the second substrate 2. It also has a function as a sealing member.
Examples of the constituent material of the spacer 7 include various resin materials such as epoxy resin, acrylic resin, urethane resin, melamine resin, and phenol resin, and various ceramic materials such as silica, alumina, and titania. These can be used alone or in combination of two or more.

The thickness (average) of the spacer 70, that is, the distance between the electrodes 3 and 4 (distance between the electrodes) is not particularly limited, but is preferably about 10 to 500 μm, and preferably about 20 to 100 μm. Is more preferable.
The spacer 70 is not limited to the configuration provided so as to surround the outer periphery of the electrophoretic display device 20. For example, the plurality of spacers 70 are arranged in the vicinity of the side portion of the electrophoretic display device 20 at a predetermined interval. It may be. In this case, the gap between the spacers 70 may be sealed with another sealing member (sealing material).

A plurality of microcapsules 40 enclosing the electrophoretic dispersion 10 and a binder material 41 are accommodated (provided) in a sealed space 71 (an internal space of a cell composed of a pair of substrates and a spacer 70). Yes.
The microcapsules 40 are disposed (arranged) in a single layer between the first substrate 1 and the second substrate 2 so as to be parallel in the vertical and horizontal directions, and contact the first electrode 3 and the second electrode 4 respectively. doing.

The constituent material of the microcapsule 40 is not particularly limited, but examples thereof include various resin materials such as a composite material of gum arabic and gelatin, a urethane resin, a melamine resin, a urea resin, a polyamide, and a polyether. Of these, one or a combination of two or more can be used.
Such microcapsules 40 are preferably substantially uniform in size. Thereby, the electrophoretic display device 20 can exhibit more excellent display performance. The microcapsules 40 having a uniform size can be obtained by using, for example, a filtration method, a specific gravity difference class method, or the like.

The size (average particle diameter) of the microcapsules 40 is not particularly limited, but is usually preferably about 20 to 200 μm, and more preferably about 30 to 100 μm. Thereby, the electrophoretic display device 20 with higher display performance can be obtained.
In such a microcapsule 40, the electrophoretic dispersion 10 is enclosed.
The production method of the microcapsule 40 (method of encapsulating the electrophoretic dispersion 10 in the microcapsule 40) is not particularly limited. For example, the interfacial polymerization method, in-situ polymerization method, phase separation method (or core separation method) Various microencapsulation methods such as a cervation method, an interfacial precipitation method, and a spray drying method can be used. The above microencapsulation method may be appropriately selected according to the constituent material of the microcapsule 40 and the like.

The electrophoretic dispersion 10 is obtained by dispersing (suspending) at least one type of electrophoretic particles 5 in a liquid phase dispersion medium 6.
For example, the electrophoretic particles 5 are dispersed in the liquid phase dispersion medium 6 by combining one or more of paint shaker method, ball mill method, media mill method, ultrasonic dispersion method, stirring dispersion method, and the like. be able to.

  As the liquid phase dispersion medium 6, a liquid having a relatively high insulating property is preferably used. Examples of the liquid phase dispersion medium 6 include alcohols such as methanol, ethanol, isopropanol, butanol, octanol, ethylene glycol, diethylene glycol, and glycerin, cellosolves such as methyl cellosolve, ethyl cellosolve, and phenyl cellosolve, methyl acetate, and ethyl acetate. , Esters such as butyl acetate and ethyl formate, ketones such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, methyl isopropyl ketone and cyclohexanone, aliphatic hydrocarbons such as pentane, hexane and octane (paraffinic hydrocarbons) ), Cycloaliphatic hydrocarbons such as cyclohexane, methylcyclohexane, benzene, toluene, xylene, hexylbenzene, hebutylbenzene, octylbenzene, nonylbenzene Aromatic hydrocarbons such as benzenes having a long-chain alkyl group (alkylbenzene derivatives) such as decylbenzene, undecylbenzene, dodecylbenzene, tridecylbenzene, tetradecylbenzene, methylene chloride, chloroform, carbon tetrachloride, 1 Halogenated hydrocarbons such as 1,2-dichloroethane, aromatic heterocycles such as pyridine, pyrazine, furan, pyrrole, thiophene, methylpyrrolidone, nitriles such as acetonitrile, propionitrile, acrylonitrile, N, N-dimethylformamide Amides such as N, N-dimethylacetamide, carboxylates or other various oils, and the like, and these can be used alone or as a mixture.

Among these, as the liquid phase dispersion medium 6, alkylbenzene derivatives (particularly dodecylbenzene) are suitable. Alkylbenzene derivatives are preferred because their raw materials are relatively inexpensive and readily available, and are highly safe.
Further, in the liquid phase dispersion medium 6 (electrophoretic dispersion liquid 10), for example, particles such as an electrolyte, a surfactant, a metal soap, a resin material, a rubber material, oils, a varnish, and a compound are used as necessary. Various additives such as dispersants such as charge control agents, titanium coupling agents, aluminum coupling agents, and silane coupling agents, lubricants, and stabilizers may be added.

  Further, the liquid phase dispersion medium 6 includes an anthraquinone dye, azo dye, indigoid dye, triphenylmethane dye, pyrazolone dye, stilbene dye, diphenylmethane dye, xanthene dye, alizarin as required. Various dyes such as a dye, an acridine dye, a quinoneimine dye, a thiazole dye, a methine dye, a nitro dye, and a nitroso dye may be dissolved.

  The electrophoretic particles 5 may be any particles as long as they are charged and can be electrophoresed in the liquid phase dispersion medium 6 by the action of an electric field. At least one of particles, resin particles, or composite particles thereof is preferably used. These particles have the advantage that they are easy to manufacture and the charge can be controlled relatively easily.

  Examples of pigments constituting the pigment particles include black pigments such as aniline black, carbon black, and titanium black, white pigments such as titanium dioxide, antimony trioxide, barium sulfate, zinc sulfide, zinc white, and silicon dioxide, monoazo, and disazo. Azo pigments such as polyazo, yellow pigments such as isoindolinone, yellow lead, yellow iron oxide, cadmium yellow, titanium yellow, antimony, azo pigments such as monoazo, disazo, polyazo, quinacridone red, chrome vermilion, etc. Examples thereof include red pigments, blue pigments such as phthalocyanine blue, indanthrene blue, bitumen, ultramarine blue, and cobalt blue, and green pigments such as phthalocyanine green. Among these, one or a combination of two or more can be used.

Examples of the resin material constituting the resin particles include acrylic resins, urethane resins, urea resins, epoxy resins, polystyrene, polyesters, and the like, and one or more of these are appropriately selected. It can be dyed and used in combination as arbitrary colored particles.
The composite particles are, for example, composed of pigment particles whose surfaces are coated with a resin material, resin particles whose surfaces are coated with a pigment, or a mixture of a pigment and a resin material mixed in an appropriate composition ratio. Particles and the like.

  The average particle diameter of the electrophoretic particles 5 is preferably about 0.1 to 10 μm, and more preferably about 0.1 to 7.5 μm. If the average particle size of the electrophoretic particles 5 is too small, a sufficient concealment rate cannot be obtained mainly in the visible light region, and as a result, the display contrast of the electrophoretic display device 20 may be reduced. If the average particle size of the electrophoretic particles 5 is too large, depending on the type or the like, the particles may easily settle in the liquid phase dispersion medium 6, which may cause problems such as deterioration in display quality of the electrophoretic display device 20. .

In such an electrophoretic display device 20, when a voltage is applied between the first electrode 3 and the second electrode 4, the electrophoretic particles 5 are applied to any electrode according to the electric field generated between them. Electrophoresis towards.
For example, when a positively charged particle is used as the electrophoretic particle 5, if the second electrode 4 is set to a positive potential, the electrophoretic particle 5 is on the first electrode 3 side as shown in FIG. To gather on the first electrode 3. For this reason, when the electrophoretic display device 20 is viewed from above (display surface side), the color of the electrophoretic particles 5 can be seen.

On the contrary, if the second electrode 4 is set to a negative potential, the electrophoretic particles 5 move to the second electrode 4 side as shown in FIG. get together. For this reason, when the electrophoretic display device 20 is viewed from above (display surface side), the color of the liquid phase dispersion medium 6 can be seen.
Accordingly, the display surface of the electrophoretic display device 20 is appropriately set by appropriately setting the physical properties (for example, color, positive / negative, charge amount) of the electrophoretic particles 5, the polarity of the electrodes 3 or 4, the potential difference between the electrodes 3 and 4, and the like. On the side, desired information (image) is displayed by the combination of the color of the electrophoretic particles 5 and the color of the liquid phase dispersion medium 6.

The specific gravity of the electrophoretic particles 5 is preferably set so as to be substantially equal to the ratio of the liquid phase dispersion medium 6. Thereby, even after the application of the voltage between the electrodes 3 and 4 is stopped, the electrophoretic particles 5 can stay in a certain position in the liquid phase dispersion 6 for a long time. That is, the information displayed on the electrophoretic display device 20 is held for a long time.
The binder material 41 is supplied for the purpose of bonding the substrates 1 and 2, the purpose of fixing the microcapsules 40 between the substrates 1 and 2, and the purpose of ensuring the insulation between the electrodes 3 and 4.

The binder material 41 in the present invention is obtained by curing a water-soluble curable resin precursor by a polymerization reaction, and the present invention is characterized in this respect. This feature will be described in detail later.
The electrophoretic display device 20 as described above can be manufactured by, for example, the following first to third manufacturing methods.

<First manufacturing method>
First, the first manufacturing method of the electrophoretic display device 20 will be described.
FIG. 3 is a cross-sectional view for explaining a first manufacturing method of the electrophoretic display device shown in FIG.
This first production method uses a water-soluble thermosetting monomer as a water-soluble curable resin precursor, [1A] a microcapsule dispersion supplying step, [2A] an oligomerization step, [ 3A] solvent removal step and [4A] substrate bonding step. Hereinafter, these steps will be sequentially described.

[1A] Microcapsule dispersion supplying step (first step)
First, a water-soluble thermosetting monomer that is a water-soluble curable resin precursor and the microcapsules 40 are dispersed and mixed in an aqueous solvent to prepare a microcapsule dispersion (microcapsule slurry).
This microcapsule dispersion is preferably prepared by mixing a solution in which a water-soluble thermosetting monomer is dissolved in an aqueous solvent and a dispersion in which microcapsules 40 are dispersed in an aqueous solvent. Thereby, the microcapsule dispersion liquid in which the water-soluble thermosetting monomer and the microcapsules 40 are uniformly dispersed can be obtained.

As the water-soluble thermosetting monomer, for example, various monomers used as raw materials for thermosetting resins such as phenol resins, amino resins, alkyd resins, acrylic resins, and epoxy resins are used.
In addition, the water-soluble thermosetting monomer may be a monomer that is a raw material for one kind of thermosetting resin, or may be a combination of two or more monomers that are raw materials for a thermosetting resin. Also good.

Examples of the monomer that is a raw material of the phenolic resin include a combination of phenols and aldehydes.
Examples of phenols include alkylphenols such as phenol, cresol and xylenol, polyphenols such as resorcin, bisphenol A, naphthol and the like. Examples of aldehydes include formaldehyde, paraform, furfural, acetaldehyde, Examples include benzaldehyde and cyclic formal such as trioxane.

Examples of the monomer that is a raw material for the amino resin include a combination of an amino raw material and formaldehyde.
Examples of amino raw materials include melamine, urea (urea), and benzoguanamine.
Examples of the monomer that is a raw material for the alkyd resin include a combination of a polyvalent carboxylic acid and a polyhydric alcohol.

Examples of the polyvalent carboxylic acid include phthalic anhydride, isophthalic acid, and maleic anhydride, and examples of the polyhydric alcohol include ethylene glycol, glycerin, pentaerythritol, and the like.
Examples of the monomer that is a raw material for the acrylic resin include acrylic acid, methacrylic acid and derivatives thereof (amide compound, ester compound), acrylonitrile, styrene, and the like.

Epoxy resins include glycidyl ether type, glycidyl ester type, and glycidyl amine type.
Among these, examples of the monomer that is a glycidyl ether type raw material include alcohols and phenols, and examples of the monomer that is a glycidyl ester type raw material include carboxylic acids and the like, and a glycidyl amine type raw material. Examples of the monomer include primary amines, secondary amines, epichlorohydrin and the like.

The aqueous solvent is a solvent having high hydrophilicity (that is, low hydrophobicity), specifically various water (distilled water, pure water, ion exchange water, RO water, etc.), methanol, ethanol, isopropanol, butanol and the like. And lower alcohols, acetone and the like. Note that a lower hydrophobic substituent such as a methoxy group may be introduced into the lower alcohols.
By using such an aqueous solvent, the penetration of the solvent into the microcapsule 40 is suppressed, and the swelling and dissolution of the microcapsule 40 due to the penetration of the solvent is prevented. Moreover, these aqueous solvents can dissolve a water-soluble thermosetting monomer satisfactorily.

  The content of the water-soluble thermosetting monomer (water-soluble curable resin precursor) in the microcapsule dispersion is preferably about 0.1 to 20% by weight, and about 0.3 to 10% by weight. Is more preferable. When there is too little content of a water-soluble thermosetting monomer, there exists a possibility that joining of the board | substrates 1 and 2 and fixation of the microcapsule 40 cannot be performed reliably. On the other hand, if the content of the water-soluble thermosetting monomer is too large, depending on the type of the water-soluble thermosetting monomer, the viscosity of the microcapsule dispersion becomes high, and it is difficult to uniformly disperse the microcapsules 40. It may be difficult to supply the microcapsule dispersion liquid with a uniform thickness on the second substrate 2 (base material).

  In addition, the content of the microcapsules 40 in the microcapsule dispersion is preferably about 10 to 70% by weight, and more preferably about 15 to 60% by weight. If the content of the microcapsules 40 is too small, the density of the microcapsules 40 in the manufactured electrophoretic display device 20 becomes too low, and it becomes difficult to display a precise image. On the other hand, if the content of the microcapsules 40 is too large, it may be difficult to dispose the microcapsules 40 as a single layer between the first substrate 1 and the second substrate 2.

To such a microcapsule dispersion, for example, a polymerization initiator, a polymerization accelerator, a polymerization retarder, etc. are added as necessary to adjust the polymerization reaction rate of the water-soluble curable resin precursor. It may be.
The microcapsule dispersion prepared as described above is supplied onto the second substrate 2 (second electrode 4) to form the coating film 7 (see FIG. 3A).

The method (supply method) for supplying the microcapsule dispersion onto the second substrate 2 is not particularly limited. For example, a doctor blade method, a spin coating method, a dip coating method, a spray coating method, a roll coating method, a screen. It is preferable to use various coating methods such as a printing method and an inkjet printing method. According to such a coating method, the film 7 having a target thickness can be formed relatively easily and accurately.
At this time, the microcapsule dispersion is preferably supplied so as to have a thickness substantially equal to the average particle diameter of the microcapsules 40. Thereby, the microcapsules 40 can be arranged on the second substrate 2 in a single layer.

[2A] Oligomerization step Next, the water-soluble thermosetting monomer contained in the film 7 is oligomerized. A part of the water-soluble thermosetting monomer may remain in a monomer state without being oligomerized.
By this oligomerization, the water-soluble thermosetting monomer becomes an oligomer, the molecular weight is increased, and it is prevented that the water-soluble thermosetting monomer is dissipated together with the aqueous solvent even when the solvent is removed in the next step [3A]. Thereby, joining of board | substrates 1 and 2 and fixation of the microcapsule 40 can be performed more reliably.

In the first production method, since a water-soluble thermosetting monomer is used as the water-soluble curable resin precursor, the oligomerization in this step [2A] is performed by heating.
At this time, part of the aqueous solvent may be volatilized depending on the heat treatment conditions.
The heating temperature (heating temperature) is preferably about 30 to 70 ° C, and more preferably about 40 to 60 ° C. If the heating temperature is too low, the oligomerization may not proceed sufficiently. On the other hand, if the heating temperature is too high, a large amount of the aqueous solvent may volatilize, and depending on the type (for example, molecular weight) of the water-soluble thermosetting monomer, part of the water-soluble thermosetting monomer may volatilize. is there.

  Further, the heating time (heating time) is not particularly limited, but when the heating temperature is in the above range, it is preferably about 5 to 45 minutes, more preferably about 10 to 30 minutes. If the heating time is too short, the oligomerization may not proceed sufficiently. On the other hand, if the heating time is too long, oligomerization proceeds too much, and the adhesiveness of the film 7 is impaired, so that the first substrate 1 may be difficult to be pressure-bonded in the next step [4A].

[3A] Solvent removal step (second step)
Next, a part or all of the aqueous solvent is removed from the coating 7.
The removal of the aqueous solvent can be performed, for example, by standing at room temperature (room temperature standing) or heating. In the method by standing at room temperature, the aqueous solvent can be removed while preventing the polymerization reaction of the water-soluble thermosetting oligomer from proceeding more than necessary, while in the method by heating, the aqueous solvent can be surely and quickly removed. Removal is possible.
In addition, when using the method by a heating, it is preferable to perform this heating on the conditions from which a water-soluble thermosetting oligomer does not completely harden | cure. Thereby, it can prevent that the viscosity of the film 7 lose | disappears, As a result, joining of the board | substrates in the following process [4A] can be performed suitably.

As such conditions, the heating temperature (heating temperature) is preferably 90 ° C. or lower, more preferably 60 ° C. or lower, and the heating time (heating time) is preferably about 1 to 60 minutes, more preferably 10 About 30 minutes.
By appropriately setting the heating temperature and the heating time, the aqueous solvent can be sufficiently removed while preventing the polymerization reaction of the water-soluble thermosetting oligomer from proceeding more than necessary.
In addition, by appropriately setting the heating conditions, the aqueous solvent can be removed while the monomer is oligomerized in this step [3A].

[4A] Substrate bonding step (third step)
Next, the first substrate 1 (first electrode 3) is opposed to the second substrate 2 (second electrode 4) with the microcapsules 40 interposed therebetween. In this state, the water-soluble thermosetting oligomer is cured by a polymerization reaction. As a result, a binder material 41 (cured product of a water-soluble thermosetting monomer) is formed, and the first substrate 1 and the second substrate 2 are joined and the microcapsules 40 are fixed (FIG. 3B). reference).

In particular, this step [4A] is preferably performed in a state in which one of the first substrate 1 and the second substrate 2 is relatively close to the other, that is, in a pressurized state. As a result, the water-soluble thermosetting oligomer and the first substrate 1 and the second substrate 2 are surely in contact with each other, so that the bonding between the substrates 1 and 2 and the fixing of the microcapsules 40 can be more reliably performed. it can.
This polymerization reaction is performed by heating, for example.

  In this case, the heating temperature (heating temperature) is preferably about 90 to 120 ° C, more preferably about 90 to 100 ° C. When the heating temperature is too low, the polymerization reaction of the water-soluble thermosetting oligomer does not proceed sufficiently, so that the water-soluble thermosetting oligomer does not reach curing. As a result, the bonding between the substrates 1 and 2 and the microcapsules There is a possibility that the fixing of 40 cannot be performed reliably. On the other hand, if the heating temperature is too high, the microcapsule 40 may be altered depending on the heating time or the like.

The heating time (heating time) is preferably about 1 to 45 minutes and more preferably about 10 to 30 minutes when the heating temperature is in the above range. With the heating time in such a range, the polymerization reaction of the water-soluble thermosetting oligomer can be sufficiently advanced to surely achieve curing.
In this step [4A], for example, irradiation with ultraviolet rays or electron beams may be used together as necessary.
The electrophoretic display device 20 is manufactured through the steps as described above.

<Second manufacturing method>
Next, a second manufacturing method of the electrophoretic display device 20 will be described.
Hereinafter, the second manufacturing method will be described with a focus on differences from the first manufacturing method, and description of similar matters will be omitted.
In the second production method, a water-soluble thermosetting oligomer is used as the water-soluble curable resin precursor, and other than that is the same as the first production method.

[1B] Microcapsule dispersion supplying step (first step)
First, a water-soluble thermosetting oligomer that is a water-soluble curable resin precursor and the microcapsules 40 are dispersed and mixed in an aqueous solvent to prepare a microcapsule dispersion (microcapsule slurry).
As a water-soluble thermosetting oligomer, the polymer (oligomer) of the thermosetting monomer quoted by the said 1st manufacturing method can be used, for example.
In addition, as the water-soluble thermosetting oligomer, an oligomer that is a raw material of one kind of thermosetting resin may be used, or an oligomer that is a raw material of two or more kinds of thermosetting resins may be used in combination. Also good.

The water-soluble thermosetting oligomer preferably has a weight average molecular weight of about 250 to 1,000, more preferably about 300 to 750. If the weight average molecular weight of the water-soluble thermosetting oligomer is too small, the water-soluble thermosetting oligomer may volatilize with the volatilization of the aqueous solvent in the next step [3B]. On the other hand, if the weight average molecular weight of the water-soluble thermosetting oligomer is too large, the oil solubility (lipophilicity) increases, so that it easily penetrates the microcapsules 40 and may be mixed in the electrophoretic dispersion liquid 10.
The content of the water-soluble thermosetting oligomer (water-soluble curable resin precursor), the content of the microcapsule 40, the type of the aqueous solvent, the method for supplying the microcapsule dispersion to the second substrate 2, and the like are as described above. This is the same as described in the first manufacturing method.
In the second production method, an oligomer is used as the water-soluble curable resin precursor, and thus the oligomerization step is omitted.

[3B] Desolvation step (second step)
A step similar to the above step [3A] is performed.
[4B] Substrate bonding step (third step)
A step similar to the step [4A] is performed.
In such a second manufacturing method, since the water-soluble thermosetting oligomer is used as the water-soluble curable resin precursor, the step for oligomerization can be omitted, and the electrophoretic display device 20 is manufactured. Time can be shortened.

<Third production method>
Next, a third manufacturing method of the electrophoretic display device 20 will be described.
Hereinafter, the third manufacturing method will be described with a focus on differences from the first manufacturing method, and description of similar matters will be omitted.
In the third production method, a water-soluble photocurable monomer is used as the water-soluble curable resin precursor, and the other processes are the same as those in the first production method.

[1C] Microcapsule dispersion supplying step (first step)
First, a water-soluble photocurable monomer that is a water-soluble curable resin precursor and the microcapsules 40 are dispersed and mixed in an aqueous solvent to prepare a microcapsule dispersion (microcapsule slurry).
Examples of the water-soluble photocurable monomer include N, N′-methylenebisacrylamide, acryloylmorpholine, vinylpyridine, N-methylacrylamide, N, N-dimethylacrylamide, N, N-dimethylaminopropylacrylamide, N, N. -Dimethylaminoethyl acrylate, diethylaminoethyl acrylate, N, N-dimethylaminoneopentyl acrylate, N-vinyl-2-pyrrolidone, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, diacetone acrylamide, N-methylol acrylamide, 2-acrylamide- Nitrogen-containing hydrophilic monomers such as 2-methylpropane sulfonic acid, sodium parastyrene sulfonate, methoxytetraethylene glycol methacrylate, Poly (oxyethylene) methacrylate, methoxy polyethylene glycol 400 methacrylate, methoxy polyethylene glycol 1000 methacrylate, methoxy triethylene glycol acrylate, methoxy polyethylene glycol 400 acrylate, polyethylene glycol 400 diacrylate, polyethylene glycol 400 dimethacrylate, polyethylene glycol 600 dimethacrylate, polyethylene Hydrophilic monomer not containing nitrogen such as glycol 1000 dimethacrylate, monomer having carboxyl group in molecule such as β-methacryloyloxyethyl hydrogen succinate, β-methacryloyloxyethyl hydrogen phthalate, 2-hydroxyethyl methacrylate 2-hydroxypropyl Monomers having a hydroxyl group in the molecule such as methacrylate, 2-hydroxyethyl acrylate, butanediol monoacrylate, p-isopropenylphenol, zinc acrylate, zinc methacrylate, metal acrylate, zinc methacrylate, Examples include monomers containing metals such as calcium methacrylate, magnesium acrylate, aluminum acrylate, barium acrylate, tin acrylate, lead acrylate, cobalt acrylate, manganese acrylate, nickel acrylate, and iron acrylate. It is done.
The water-soluble photocurable monomer may be a monomer that is a raw material for one type of photocurable resin, or may be a combination of two or more monomers that are a raw material for a photocurable resin. Also good.
The content of the water-soluble photocurable monomer (water-soluble curable resin precursor), the content of the microcapsule 40, the type of the aqueous solvent, the method of supplying the microcapsule dispersion to the second substrate 2, and the like are as described above. This is the same as described in the first manufacturing method.

[2C] Oligomerization Step Next, the water-soluble photocurable monomer contained in the film 7 is oligomerized. A part of the water-soluble photocurable monomer may remain in a monomer state without being oligomerized.
In the third production method, since a water-soluble photocurable monomer is used as the water-soluble curable resin precursor, the oligomerization in this step [2C] is performed by light irradiation.

The light used for irradiation is appropriately selected according to the water-soluble photocurable monomer to be used, and is not particularly limited, and examples thereof include ultraviolet rays and visible light.
The intensity (illumination intensity) of the irradiated light is in the range of about 50~3000J / cm ² and more preferably preferably 100~1000J / cm ² approximately. If the light intensity is too weak, oligomerization may not proceed sufficiently. On the other hand, even if the light intensity is increased beyond the upper limit, no further increase in effect can be expected.

  The irradiation time (irradiation time) is not particularly limited, but when the irradiation intensity is in the above range, it is preferably about 1 to 45 minutes, and more preferably about 10 to 30 minutes. If the irradiation time is too short, oligomerization may not proceed sufficiently depending on the type of water-soluble photocurable monomer. On the other hand, if the irradiation time is too long, oligomerization proceeds too much, and the adhesiveness of the film 7 is impaired. As a result, it is difficult to press-bond the first substrate 1 in the next step [4C].

[3C] Solvent removal step (second step)
A step similar to the above step [3A] is performed.
[4C] Substrate bonding step (third step)
A step similar to the step [4A] is performed.
As described above, in the method for manufacturing an electrophoretic display device of the present invention, the substrates 1 and 2 and the microcapsules 40 are fixed by the binder material 41 which is a cured product of the water-soluble curable resin precursor.

Here, since the water-soluble curable resin precursor is well dissolved in the aqueous solvent, it is not necessary to add a surfactant or the like for dissolution in the aqueous solvent.
Moreover, since adhesion and fixing by a cured product obtained by a polymerization reaction are excellent in strength, it is not necessary to add an adhesion reinforcing agent to an aqueous solvent.
Accordingly, it is possible to avoid a decrease in the charge amount of the electrophoretic particles 5 due to the intrusion of the surfactant or the adhesion enhancing agent into the microcapsule 40, and to stably manufacture the electrophoretic display device 20 having excellent display performance. can do.

Second Embodiment
Next, a second embodiment of the electrophoretic display device of the present invention will be described.
FIG. 4 is a vertical cross-sectional view (showing an operating state) showing a second embodiment of the electrophoretic display device of the present invention.
Hereinafter, the electrophoretic display device according to the second embodiment will be described focusing on the differences from the electrophoretic display device according to the first embodiment, and description of similar matters will be omitted.

In the electrophoretic display device 20 of the second embodiment, the liquid phase dispersion medium 6 has a plurality of types of electrophoretic particles having different characteristics, specifically, two types of electrophoretic particles having different colors (hues) and charges. Is the same as the electrophoretic display device 20 of the second embodiment except that is dispersed.
In the present embodiment, an example in which the electrophoretic particles 5a are positively charged and white and the electrophoretic particles 5b are negatively charged and black (colored) is used as an example. To do.

In the electrophoretic display device 20, when the second electrode 4 is set to a positive potential, the electrophoretic particles 5 a move to the first electrode 3 side and gather on the first electrode 3. The particles 5 b move to the second electrode 4 side and gather at the second electrode 4.
On the contrary, when the second electrode 4 is set to a negative potential, the electrophoretic particles 5a move to the second electrode 4 side and gather at the second electrode 4, while the electrophoretic particles 5b It moves to the first electrode 3 side and gathers at the first electrode 3.

  Therefore, as shown in FIG. 4, when the electrophoretic display device 20 is viewed from above (display surface side) by the combination of the second electrodes 4, the color (white) of the electrophoretic particles 5 a in the left microcapsule 40. However, in the center microcapsule 40, the color (gray) in which the color of the electrophoretic particles 5b of the electrophoretic particles 5a is mixed, and in the right microcapsule 40, the color (black) of the electrophoretic particles 5b is You will see each one.

With this configuration, the electrophoretic display device 20 can display a multi-tone image.
In the illustrated configuration, the electrophoretic particles 5a and the electrophoretic particles 5b are approximately the same number and are dispersed in the liquid phase dispersion medium 6. However, these numbers may be set according to the purpose. .
Further, the average particle diameter of the electrophoretic particles 5a and the average particle diameter of the electrophoretic particles 5b may be the same or different.

Further, the same type of electrophoretic particles may be used for one microcapsule 40, and the type of electrophoretic particles may be different for each microcapsule 40.
The electrophoretic display device 20 according to the second embodiment can obtain the same operations and effects as those of the first embodiment.
The electrophoretic display device 20 as described above can be incorporated into various electronic devices. Hereinafter, the electronic apparatus of the present invention including the electrophoretic display device 20 will be described.

<< Electronic Paper >>
First, an embodiment when the electronic apparatus of the present invention is suitable for electronic paper will be described.
FIG. 5 is a perspective view showing an embodiment when the electronic apparatus of the present invention is applied to electronic paper.
An electronic paper 600 shown in FIG. 5 includes a main body 601 composed of a rewritable sheet having the same texture and flexibility as paper, and a display unit 602.
In such an electronic paper 600, the display unit 602 includes the electrophoretic display device 20 as described above.

<< Display >>
Next, an embodiment when the electronic apparatus of the present invention is applied to a display will be described.
FIG. 6 is a diagram showing an embodiment when the electronic apparatus of the present invention is applied to a display. Among these, FIG. 6A is a sectional view and FIG. 6B is a plan view.
A display (display device) 800 shown in FIG. 6 includes a main body 801 and an electronic paper 600 that is detachably attached to the main body 801. The electronic paper 600 has the same configuration as described above, that is, the configuration shown in FIG.

  The main body 801 has an insertion port 805 into which the electronic paper 600 can be inserted on the side (right side in FIG. 6), and two pairs of conveying rollers 802a and 802b are provided inside. When the electronic paper 600 is inserted into the main body 801 through the insertion port 805, the electronic paper 600 is installed in the main body 801 in a state of being sandwiched between the pair of conveyance rollers 802a and 802b.

  A rectangular hole 803 is formed on the display surface side of the main body 801 (the front side in FIG. 6B), and a transparent glass plate 804 is fitted in the hole 803. . Thereby, the electronic paper 600 installed in the main body 801 can be viewed from the outside of the main body 801. That is, in the display 800, the display surface is configured by visually recognizing the electronic paper 600 installed in the main body 801 on the transparent glass plate 804.

Further, a terminal portion 806 is provided at the leading end portion (left side in FIG. 6) of the electronic paper 600 in the insertion direction, and the terminal with the electronic paper 600 installed in the main body portion 801 is provided inside the main body portion 801. A socket 807 to which the unit 806 is connected is provided. A controller 808 and an operation unit 809 are electrically connected to the socket 807.
In such a display 800, the electronic paper 600 is detachably installed on the main body 801, and can be carried and used while being detached from the main body 801.

In such a display 800, the electronic paper 600 is configured by the electrophoretic display device 20 as described above.
Note that the electronic apparatus of the present invention is not limited to the application to the above. For example, a television, a digital still video camera, a viewfinder type, a monitor direct-view type video tape recorder, a car navigation device, a pager, an electronic Examples include notebooks, calculators, electronic newspapers, electronic books, electronic notebooks, word processors, personal computers, workstations, videophones, POS terminals, devices with touch panels, etc. It is possible to apply the electrophoretic display device 20 of the invention.

As described above, the method for manufacturing an electrophoretic display device, the electrophoretic display device, and the electronic apparatus of the present invention have been described based on the illustrated embodiments. However, the present invention is not limited to these.
For example, in each of the embodiments described above, the case where a water-soluble thermosetting monomer or oligomer or a water-soluble photocurable monomer is used as the water-soluble curable resin precursor has been described. For example, other types of water-soluble curable resin precursors such as water-soluble photocurable oligomers, water-soluble anaerobic curable monomers or oligomers, water-soluble reactive curable monomers or oligomers can be used.

Further, the water-soluble curable resin precursor may be used by mixing a monomer and an oligomer.
In addition, the method for manufacturing an electrophoretic display device and the electrophoretic display device of the present invention may be a combination of any two or more configurations (features) of the above embodiments.
Further, in each of the above embodiments, a configuration in which a pair of electrodes are provided to face each other has been described. However, the electrophoretic display device of the present invention is applied to a configuration in which a pair of electrodes is provided on the same substrate. You can also.

Next, specific examples of the present invention will be described.
<Preparation of microcapsules>
First, titania particles (Ishihara Sangyo Co., Ltd., “CR-90”) having an average particle size of 0.3 μm, titania coupling agent (Ajinomoto Co., “KR TTS”), and aluminum coupling agent (Ajinomoto Co., Inc.). ("AL-M").

Next, the titania particles were dispersed in dodecylbenzene (manufactured by Kanto Chemical Co., Inc.), and further mixed with an anthraquinone blue dye (manufactured by Chuo Synthetic Chemical Co., Ltd.) to prepare an electrophoretic dispersion medium.
Next, this electrophoretic dispersion medium was dropped into a solution in which gum arabic and gelatin were dissolved and stirred. The rotational speed of stirring was 1300 rpm.
Next, the pH of the solution was adjusted to 3.7 using acetic acid, and then capsules were precipitated by cooling with ice. Further, formaldehyde was added to form a crosslinked structure in the capsule.
Next, after stirring all day and night, classification was performed to obtain microcapsules (average particle size 55 μm).

(Example 1)
The obtained microcapsules were dispersed in water so that the weight ratio of microcapsules: water was 2: 1.
Further, 6 g of acrylamide (water-soluble thermosetting monomer) and 0.03 g of benzoyl peroxide were dissolved in 100 g of 1-methoxypropanol.

Next, this solution was mixed with a dispersion liquid 36 g containing microcapsules to prepare a microcapsule dispersion liquid.
The content of each component in the microcapsule dispersion is about 17% by weight of microcapsules and about 4% by weight of acrylamide.
Next, a second substrate on which a second electrode made of ITO was formed was prepared.
Next, the microcapsule dispersion was applied (supplied) onto the second substrate by a doctor blade method to form a coating film (film) having an average thickness of 60 μm.

Next, the coating film was subjected to heat treatment at 60 ° C. for 30 minutes, and subsequently at 90 ° C. for 30 minutes. The polymerization reaction of the monomer was advanced by oligomerization by a heat treatment at 60 ° C., and the polymerization reaction was further advanced by a heat treatment (desolvation) at 90 ° C. within a range that did not completely cure.
Next, the first substrate on which the first electrode made of ITO is formed is pressure-bonded to the surface of the coating film, and in this state, the coating film is cured by heat treatment at 90 ° C. for 10 minutes. The bonding between the first substrate and the second substrate and the microcapsules were fixed. Thereby, the electrophoretic display device shown in FIG. 1 was obtained.

(Example 2)
The obtained microcapsules were dispersed in water so that the weight ratio of microcapsules: water was 2: 1.
Further, 6 g of acrylamide (water-soluble thermosetting monomer), 1 g of poly (oxyethylene) methacrylate (water-soluble thermosetting monomer), and 0.06 g of 2,2-bis (2-methylbutyronitrile), It was dissolved in 100 g of 1-methoxy-2-propanol.

Next, this solution was mixed with a dispersion liquid 36 g containing microcapsules to prepare a microcapsule dispersion liquid.
The content of each component in the microcapsule dispersion is about 17% by weight of microcapsules and about 5% by weight of acrylamide and poly (oxyethylene) methacrylate.
Next, a second substrate on which a second electrode made of ITO was formed was prepared.

  Next, the microcapsule dispersion was applied (supplied) onto the second substrate by a doctor blade method to form a coating film (film) having an average thickness of 60 μm.

Next, the coating film was subjected to heat treatment (desolvation) at 60 ° C. for 60 minutes. By this heat treatment, the monomer was oligomerized and the polymerization reaction was allowed to proceed within a range that did not completely cure.
Next, the first substrate on which the first electrode made of ITO is formed is pressure-bonded to the surface of the coating film, and in this state, the coating film is cured by applying heat treatment at 100 ° C. for 10 minutes. The bonding between the first substrate and the second substrate and the microcapsules were fixed. Thereby, the electrophoretic display device shown in FIG. 1 was obtained.

(Example 3)
The obtained microcapsules were dispersed in water so that the weight ratio of microcapsules: water was 2: 1.
Further, 21 g of 2-hydroxyethyl methacrylate (water-soluble photocurable monomer), 9 g of poly (oxyethylene) methacrylate (water-soluble photocurable monomer), and 0.3 g of 1-hydroxycyclohexyl phenyl ketone are added to 100 g of water. Dissolved.

Next, this solution and 360 g of a dispersion containing microcapsules were mixed to prepare a microcapsule dispersion.
The content of each component in the microcapsule dispersion is about 49% by weight of microcapsules and about 6% by weight of 2-hydroxyethyl methacrylate and poly (oxyethylene) methacrylate.
Next, a second substrate on which a second electrode made of ITO was formed was prepared.

Next, the microcapsule dispersion was applied (supplied) onto the second substrate by a doctor blade method to form a coating film (film) having an average thickness of 60 μm.
Next, the coating film was irradiated with ultraviolet rays of 150 J / cm ² for 10 minutes, and subsequently subjected to heat treatment at 90 ° C. for 30 minutes. In addition, the polymerization reaction of the monomer was allowed to proceed by oligomerization by irradiation with ultraviolet rays, and the polymerization reaction was allowed to proceed within a range that did not completely cure by heat treatment (desolvation).
Next, the first substrate on which the first electrode made of ITO is formed is pressure-bonded to the surface of the coating film, and in this state, the coating film is cured by heat treatment at 90 ° C. for 10 minutes. The bonding between the first substrate and the second substrate and the microcapsules were fixed. Thereby, the electrophoretic display device shown in FIG. 1 was obtained.

Example 4
The obtained microcapsules were dispersed in water so that the weight ratio of microcapsules: water was 2: 1.
Further, 10 g of 30 wt% aqueous polyvinyl methyl ether solution, 0.3 g of polyethylene glycol 400 diacrylate (water-soluble photocurable monomer), 0.17 g of (4-benzoylbenzyl) trimethylammonium chloride, and 4 g of water were mixed. .

Next, this solution was mixed with 60 g of a dispersion containing microcapsules to prepare a microcapsule dispersion.
The content of each component in the microcapsule dispersion is about 56% by weight of microcapsules and about 400% by weight of polyethylene glycol 400 diacrylate.
Next, a second substrate on which a second electrode made of ITO was formed was prepared.
Next, the microcapsule dispersion was applied (supplied) onto the second substrate by a doctor blade method to form a coating film (film) having an average thickness of 60 μm.

Next, the coating film was irradiated with ultraviolet rays of 150 J / cm ² for 10 minutes, and subsequently subjected to heat treatment at 90 ° C. for 30 minutes. In addition, the polymerization reaction of the monomer was allowed to proceed by oligomerization by irradiation with ultraviolet rays, and the polymerization reaction was allowed to proceed within a range that did not completely cure by heat treatment (desolvation).
Next, the first substrate on which the first electrode made of ITO is formed is pressure-bonded to the surface of the coating film, and in this state, the coating film is cured by heat treatment at 90 ° C. for 10 minutes. The bonding between the first substrate and the second substrate and the microcapsules were fixed. Thereby, the electrophoretic display device shown in FIG. 1 was obtained.

(Example 5)
The obtained microcapsules were dispersed in water so that the weight ratio of microcapsules: water was 2: 1.
Moreover, 6 g of polyacrylamide (water-soluble thermosetting oligomer) having a weight average molecular weight of 700 and 0.03 g of benzoyl peroxide were dissolved in 100 g of 1-methoxypropanol.

Next, this solution was mixed with a dispersion liquid 36 g containing microcapsules to prepare a microcapsule dispersion liquid.
The content of each component in the microcapsule dispersion is about 17% by weight of microcapsules and about 4% by weight of polyacrylamide.
Next, a second substrate on which a second electrode made of ITO was formed was prepared.

Next, the microcapsule dispersion was applied (supplied) onto the second substrate by a doctor blade method to form a coating film (film) having an average thickness of 60 μm.
Next, the coating film was subjected to heat treatment (desolvation) at 90 ° C. for 30 minutes. As a result, the polymerization reaction was allowed to proceed in a range where the oligomer did not completely cure.
Next, the first substrate on which the first electrode made of ITO is formed is pressure-bonded to the surface of the coating film, and in this state, the coating film is cured by heat treatment at 90 ° C. for 10 minutes. The bonding between the first substrate and the second substrate and the microcapsules were fixed. Thereby, the electrophoretic display device shown in FIG. 1 was obtained.

(Example 6)
The obtained microcapsules were dispersed in water so that the weight ratio of microcapsules: water was 2: 1.
Further, 3 g of acrylamide (water-soluble thermosetting monomer), 3 g of polyacrylamide (water-soluble thermosetting oligomer) having a weight average molecular weight of 700, and 0.03 g of benzoyl peroxide were dissolved in 100 g of 1-methoxypropanol.

Next, this solution was mixed with a dispersion liquid 36 g containing microcapsules to prepare a microcapsule dispersion liquid.
The content of each component in the microcapsule dispersion is about 17% by weight of microcapsules and about 4% by weight of acrylamide and polyacrylamide.
Next, a second substrate on which a second electrode made of ITO was formed was prepared.
Next, the microcapsule dispersion was applied (supplied) onto the second substrate by a doctor blade method to form a coating film (film) having an average thickness of 60 μm.

Next, the coating film was subjected to heat treatment at 60 ° C. for 30 minutes, and subsequently at 90 ° C. for 30 minutes. The polymerization reaction of the monomer was advanced by oligomerization by a heat treatment at 60 ° C., and the polymerization reaction was further advanced by a heat treatment (desolvation) at 90 ° C. within a range that did not completely cure.
Next, the first substrate on which the first electrode made of ITO is formed is pressure-bonded to the surface of the coating film, and in this state, the coating film is cured by heat treatment at 90 ° C. for 10 minutes. The bonding between the first substrate and the second substrate and the microcapsules were fixed. Thereby, the electrophoretic display device shown in FIG. 1 was obtained.

(Comparative example)
The obtained microcapsules were dispersed in water so that the weight ratio of microcapsules: water was 2: 1.
A microcapsule dispersion liquid was prepared by mixing 8 g of this dispersion liquid and 2 g of a silicon-based binder material (manufactured by Shin-Etsu Chemical Co., Ltd., “Polon”) as an emulsion binder material.

Next, a second substrate on which a second electrode made of ITO was formed was prepared.
Next, the microcapsule dispersion was applied (supplied) onto the second substrate by a doctor blade method to form a coating film (film) having an average thickness of 60 μm.
Next, after drying this coating film, the first substrate on which the first electrode made of ITO is formed is pressure-bonded to the coating film surface, and in this state, heat treatment is performed at 120 ° C. for 10 minutes. The coating film was cured to bond the first substrate and the second substrate and fix the microcapsules. Thereby, the electrophoretic display device shown in FIG. 1 was obtained.

[Evaluation]
The electrophoretic display devices manufactured in each example and comparative example were subjected to an aging test, and the change with time of the drive voltage was examined.
As a result, in each of the electrophoretic display devices (electrophoretic display devices of the present invention) manufactured in each example, the drive voltage was maintained at a substantially constant value without changing with time.

  In contrast, in the electrophoretic display device manufactured in the comparative example, the driving voltage increased with time, and sufficient contrast could not be obtained with low voltage driving. This is considered to be the result of various ionic additives added to the emulsion binder material entering into the microcapsule and adversely affecting the charged particles, such as reducing the charge amount. .

1 is a longitudinal sectional view showing a first embodiment of an electrophoretic display device of the present invention. It is a schematic diagram which shows the principle of operation of the electrophoretic display device shown in FIG. It is sectional drawing for demonstrating the 1st manufacturing method of the electrophoretic display device shown in FIG. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the electrophoretic display device of this invention. It is a perspective view which shows embodiment at the time of applying the electronic device of this invention to electronic paper. It is a figure which shows embodiment at the time of applying the electronic device of this invention to a display. It is a schematic diagram which shows the working principle of the conventional electrophoretic display device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... 1st board | substrate 2 ... 2nd board | substrate 3 ... 1st electrode 4 ... 2nd electrode 5, 5a, 5b ... Electrophoretic particle 6 ... Liquid phase dispersion medium 7 ... Coating film 10 Electrophoretic dispersion 20 Electrophoretic display device 40 Microcapsule 41 Binder material 70 Spacer 71 Sealed space 600 Electronic paper 601 Main unit 602 Display unit 800 Display 801 ... Main unit 802a, 802b ... Conveying roller pair 803 ... Hole 804 ... Transparent glass 805 ... Insertion port 806 ... Terminal part 807 ... Socket 808 ... Controller 809 ... Operation part 903 ... 1 electrode 904 2nd electrode 905 electrophoretic particle 906 liquid phase dispersion medium 920 electrophoretic display device

Claims (15)

A microcapsule dispersion liquid containing an electrophoretic dispersion liquid containing at least one kind of electrophoretic particles, a water-soluble curable resin precursor, and an aqueous solvent is supplied onto a substrate including an electrode. A first step;
A second step of removing at least a part of the aqueous solvent;
A third step of bonding the counter substrate and the substrate by curing the curable resin precursor by a polymerization reaction with the counter substrate opposed to the substrate via the microcapsule. A method of manufacturing an electrophoretic display device.   The method for producing an electrophoretic display device according to claim 1, wherein the water-soluble curable resin precursor includes a monomer.   The method for producing an electrophoretic display device according to claim 2, wherein the monomer is oligomerized in the second step or prior to the second step.   The method for manufacturing an electrophoretic display device according to claim 1, wherein the water-soluble curable resin precursor includes an oligomer.   The method for manufacturing an electrophoretic display device according to claim 4, wherein the oligomer has a weight average molecular weight of 250 to 1,000.   The method for producing an electrophoretic display device according to claim 1, wherein the water-soluble curable resin precursor starts a polymerization reaction by heating or light irradiation.   The method for manufacturing an electrophoretic display device according to claim 1, wherein the content of the water-soluble curable resin precursor in the microcapsule dispersion is 0.1 to 20% by weight.   The method for manufacturing an electrophoretic display device according to claim 1, wherein in the second step, the aqueous solvent is removed by standing at room temperature or heating.   The method for manufacturing an electrophoretic display device according to claim 8, wherein the heating in the second step is performed under a condition in which the water-soluble curable resin precursor does not completely cure.   10. The electrophoretic display device according to claim 1, wherein in the first step, the microcapsule dispersion is supplied onto the substrate so as to have a thickness substantially equal to an average particle diameter of the microcapsules. Manufacturing method.   The method for manufacturing an electrophoretic display device according to claim 1, wherein an average particle diameter of the microcapsules is 20 to 200 μm.   The method for manufacturing an electrophoretic display device according to claim 1, wherein the content of the microcapsules in the microcapsule dispersion is 10 to 70% by weight.   In the third step, the water-soluble curable resin precursor is cured in a state where one of the counter substrate and the substrate is relatively close to the other. A method for producing an electrophoretic display device according to claim 1. A substrate comprising electrodes;
A plurality of microcapsules disposed on the substrate and encapsulating an electrophoretic dispersion containing at least one type of electrophoretic particles;
A counter substrate disposed opposite to the substrate via the microcapsule;
An electrophoretic display device having a binder material bonded to the substrate and the counter substrate,
The electrophoretic display device, wherein the binder material is obtained by curing a water-soluble curable resin precursor by a polymerization reaction. An electronic apparatus comprising the electrophoretic display device according to claim 14.

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