JP2005084343A - Electrophoretic display device and electronic appliance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophoretic display device which is excellent in persuasiveness of displayed contents and in visibility and an electronic appliance. <P>SOLUTION: The electrophoretic display device 20 is provided with an electrode, a pair of opposing substrates and an electrophoretic dispersion liquid layer arranged between the pair of substrates and having an electrophoretic dispersion liquid containing at least a kind of electrophoretic particles and has a first display region 81 and a second display region 82 with mutually different display colors. In a part corresponding to the first display region 81, micro capsules which display, for example, a white color and a first color different from white (for example, red, green, blue, black etc.) are disposed (switch between the white color and the first color) and in a part corresponding to the second display region 82, micro capsules which display, for example, the white color and a second color different from white or the first color (for example, red, green, blue, black etc.) are disposed (switch between the white color and the second color). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to 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.

  Examples of such an electrophoretic display device include an electrophoretic dispersion liquid in which electrophoretic particles are dispersed in a liquid phase dispersion medium between a pair of substrates having electrodes, or a pair of electrodes having electrodes. A microcapsule type in which a plurality of microcapsules enclosing the electrophoretic dispersion liquid and a binder material for fixing each substrate and the microcapsules are disposed between the substrates is known (for example, Patent Document 1). reference).

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 a pair of substrates, the electrophoretic particles 905 in the microcapsule cause 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.
However, the conventional electrophoretic display device has a disadvantage that it lacks persuasiveness and visibility of the display content because it displays a single color such as white and black.

JP 2001-56653 A

  An object of the present invention is to provide an electrophoretic display device and an electronic apparatus that are excellent in persuasiveness and visibility of display contents.

Such an object is achieved by the present invention described below.
An electrophoretic display device of the present invention includes an electrode, a substrate, and an electrophoretic dispersion liquid layer provided on the substrate and having an electrophoretic dispersion liquid containing at least one kind of electrophoretic particles. Because
It has a plurality of display areas with different display colors.
This improves the persuasiveness and visibility of the display content. In particular, it is very effective when used in a bright place such as daytime.

The electrophoretic display device of the present invention includes an electrophoretic dispersion liquid layer that includes an electrode, a pair of opposing substrates, and an electrophoretic dispersion liquid that is provided between the pair of substrates and includes at least one kind of electrophoretic particles. An electrophoretic display device comprising:
It has a plurality of display areas with different display colors.
This improves the persuasiveness and visibility of the display content. In particular, it is very effective when used in a bright place such as daytime.

In the electrophoretic display device of the present invention, it is preferable that at least one of the plurality of display areas is configured to change display contents.
Thereby, versatility becomes wide.
In the electrophoretic display device according to the aspect of the invention, it is preferable that display content is constant in at least one of the plurality of display regions.
Thereby, a structure can be simplified and cost can be reduced.

In the electrophoretic display device of the present invention, it is preferable that the electrophoretic dispersion layer is configured by arranging a plurality of microcapsules encapsulating the electrophoretic dispersion.
As a result, the electrophoretic display device can be easily manufactured, and the cost can be reduced.
In the electrophoretic display device of the present invention, it is preferable that a plurality of types of electrophoretic particles having different characteristics are used as the electrophoretic particles in each display region.
Thereby, an electrophoretic display device excellent in display performance can be obtained.
In the electrophoretic display device of the present invention, it is preferable that at least two types of electrophoretic particles having different colors and charging polarities are used as the electrophoretic particles in each display region.
Thereby, an electrophoretic display device excellent in display performance can be obtained.

In the electrophoretic display device of the present invention, in each of the display regions, as the electrophoretic particles, at least inorganic particles and a color different from the color of the inorganic particles, and the charged polarity of the inorganic particles It is preferable to use resin particles having opposite charging polarities.
Thereby, aggregation of electrophoretic particles (aggregation of inorganic particles and resin particles) can be prevented more reliably, and thereby display performance can be further improved.
An electronic apparatus according to the present invention includes the electrophoretic display device according to the present invention.
Thereby, an electronic apparatus having an electrophoretic display device with high persuasiveness and visibility of display contents can be provided.

Hereinafter, an electrophoretic display device and an electronic apparatus of 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 an electrophoretic display device according to a first embodiment of the present invention, FIG. 2 is a schematic diagram showing an operation principle of the electrophoretic display device shown in FIG. 1, and FIG. 3 is shown in FIG. It is a top view of an electrophoretic display device.
In the following description, for convenience of explanation, the upper side in FIGS. 1 and 2 is described as “upper” or “upper”, and the lower side is described as “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, the electrophoretic display device 20 useful for constructing a deformable electronic device such as electronic paper, for example. 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, polyvinyl alcohol, polycarbonate, polyethylene oxide, polyvinyl butyral, polyvinyl carbazole, vinyl acetate, or the like, NaCl, LiClO ₄ , KCl, H ₂ O, LiCl, 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 ( nO _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 resins 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 7 is provided.

In this embodiment, the spacer 7 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. One or more of these can be used in combination.

The thickness (average) of the spacers 7, 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 about 20 to 100 μm. Is more preferable.
The spacer 7 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 7 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 7 may be sealed with another sealing member (sealing material). Further, the spacer 7 may be omitted.

In the sealed space 71 (inner space of the cell), a plurality of microcapsules 40 enclosing the electrophoretic dispersion 10 and a binder material 41 are provided. The plurality of microcapsules 40 and the binder material 41 constitute an electrophoretic dispersion liquid layer.
The microcapsules 40 are disposed between the first substrate 1 and the second substrate 2 in a single layer (one by one without overlapping in the thickness direction) so as to be arranged in parallel in the vertical and horizontal directions, and each of the first electrodes 3. And in contact with the second electrode 4. In the present embodiment, one microcapsule 40 is arranged for two adjacent second electrodes 4. That is, the microcapsule 40 is disposed so as to straddle the two adjacent second electrodes 4.

The microcapsule 40 is configured by enclosing the electrophoretic dispersion 10 in a capsule body 401.
The constituent material of the capsule body 401 is not particularly limited, and examples thereof include various resin materials such as a composite material of gum arabic and gelatin, urethane resin, melamine resin, urea resin, polyamide, and polyether. These can be used alone or in combination of two or more.

  In addition, the method for producing the microcapsule 40 (method for encapsulating the electrophoretic dispersion 10 in the capsule body 401) 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.

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 10 to 150 μm, and more preferably about 30 to 100 μm.

The electrophoretic dispersion 10 is obtained by dispersing (suspending) at least one type of electrophoretic particles in the liquid phase dispersion medium 6. The dispersion of the electrophoretic particles in the liquid phase dispersion medium 6 is performed by, for example, one or more of paint shaker method, ball mill method, media mill method, ultrasonic dispersion method, stirring dispersion method, and the like. Can do.
The electrophoretic dispersion liquid 10 is roughly classified into a type in which one type of electrophoretic particle is dispersed in the liquid phase dispersion medium 6 and a plurality of types of electrophoretic particles having different characteristics in the liquid phase dispersion medium 6. Although there exist the thing of the form etc. which are distributed, any of these may be used.

Examples of the latter include those in which two types of electrophoretic particles having different colors (hue) and charged polarities (charges) are dispersed in the liquid phase dispersion medium 6. In particular, the electrophoretic particles preferably include inorganic particles and resin particles that are colored in a color different from the color of the inorganic particles and have a charging polarity opposite to the charging polarity of the inorganic particles.
By using a combination of inorganic particles and resin particles as the electrophoretic particles, aggregation of the electrophoretic particles can be more reliably prevented.

In the present embodiment, two types of electrophoretic particles, white inorganic particles 5a and colored resin particles 5b, are used.
The inorganic particles (electrophoretic particles) 5a and the resin particles (electrophoretic particles) 5b are particles that have a charge and can be electrophoresed in the liquid dispersion medium 6 by the action of an electric field. Any material can be used and is not particularly limited.

  Examples of the inorganic particles 5a include titanium oxide (titania), bitumen, ultramarine blue, phthalocyanine blue, chrome yellow, cadmium yellow, lithopone, molybdate orange, first yellow, benzimidazoline yellow, flavans yellow, naphthol yellow, and benzimidazolone. Orange, Perinone Orange, Bengala, Cadmium Red, Madalake, Naphthol Red, Dioxazine Violet, Phthalocyanine Blue, Alkaline Blue, Cerulean Blue, Emerald Green, Phthalocyanine Green, Pigment Green, Cobalt Green, Aniline Black, etc. Various compounds such as zinc white, barium sulfate, chromium oxide, calcium carbonate, gypsum, lead white, carbon black and iron black can be used. .

Among these, the inorganic particles 5a are preferably composed mainly of titanium oxide. Such inorganic particles 5a mainly composed of titanium oxide are preferable because they have high whiteness and particularly low cohesiveness with the resin particles 5b.
Moreover, it is preferable that the inorganic particle 5a has a surface subjected to a treatment for improving the dispersibility with respect to the liquid phase dispersion medium 6. Thereby, the dispersibility to the liquid phase dispersion medium 6 of the inorganic particle 5a improves, As a result, aggregation with the resin particle 5b can be prevented more reliably.

As the surface treatment of the inorganic particles 5a, a treatment with a surface treatment agent such as a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, or a zirconium coupling agent is suitable.
In particular, as the surface treatment agent, a titanate coupling agent (Ajinomoto Co., “KR TTS”) and an aluminum coupling agent (Ajinomoto Co., “AL-M”) are preferable.

On the other hand, as the resin particles 5b, for example, particles obtained by an emulsion polymerization method or the like can be used.
Examples of the resin material constituting the resin particles 5b include acrylic resins, urethane resins, urea resins, epoxy resins, melamine resins, polystyrene, polyester, divinylbenzene, and the like. Species or a combination of two or more can be used.

Among these, as a resin material which comprises the resin particle 5b, what has an acrylic resin as a main component is preferable. By constituting the resin particles 5b mainly with an acrylic resin, aggregation with the inorganic particles 5a can be more reliably prevented.
In addition, the resin preferably has a polar group such as a hydroxyl group, an amino group, or a carboxyl group in its molecular structure. By introducing such a polar group, the polar group is introduced into the molecular structure of the resin and insolubilized in the solvent. As a result, the resistance of the resin particles 5b to the liquid phase dispersion medium 6 can be improved.
From this point of view, the polar group is preferably at least one of a hydroxyl group and an amino group, and particularly preferably an amino group.

In view of the above, the resin is preferably an acrylic resin having at least one of a hydroxyl group and an amino group as a polar group.
Such an acrylic resin can be obtained, for example, by copolymerizing an acrylic resin having a polar group and introducing the polar group into the acrylic resin. According to this method, an acrylic resin having a polar group can be obtained relatively easily and with a high yield.

In addition, the charging property in the liquid phase dispersion medium 6 of the resin particle 5b can be adjusted by setting the introduction amount of the polar group as appropriate.
The resin particles 5b are colored in any one of red, green, blue and black by mixing pigments such as dyes and pigments. Thus, the electrophoretic display device 20 can display the color of the inorganic particles 5a, the color of the resin particles 5b, and a mixed color thereof.
It is preferable that the average particle size of the inorganic particles 5a and the average particle size of the resin particles 5b satisfy the following relationship.

  That is, when the average particle diameter of the inorganic particles 5a is A [μm] and the average particle diameter of the resin particles 5b is B [μm], it is preferable that B / A satisfies the relationship of 1.5 to 200, It is more preferable to satisfy the relationship of 5-50. Thereby, aggregation of the inorganic particles 5a and the resin particles 5b can be effectively prevented while suitably maintaining the dispersibility of the particles 5a and 5b in the liquid phase dispersion medium 6.

Specifically, the average particle size B of the resin particles 5b is preferably about 0.5 to 20 μm, and more preferably about 2 to 10 μm. By making the average particle diameter B of the resin particles 5b within the above range, the above effects are more suitably exhibited, and effects such as prevention of thickness reduction of the electrophoretic display device 20 and reduction in manufacturing efficiency are exhibited. The
In addition, when the surface treatment (adsorption of the surfactant to the surface of the inorganic particles 5a) of the inorganic particles 5a with a surfactant is performed, if the average particle size B of the resin particles 5b is too small, The inorganic particles 5a may enter the hydrophobic chain, and as a result, the inorganic particles 5a and the resin particles 5b may aggregate. However, even when the inorganic particles 5a are surface-treated with a surfactant, the inorganic particles 5a and the resin particles 5b can be obtained by setting the average particle size B of the inorganic particles 5a to 0.5 μm or more (particularly 2 μm or more). Can be effectively prevented from aggregating.
Also from this viewpoint, it is preferable to omit the surface treatment of the inorganic particles 5a with the surfactant.

On the other hand, the average particle size A of the inorganic particles 5a is preferably about 0.1 to 10 μm, more preferably about 0.1 to 7.5 μm, and particularly about 0.2 to 0.3 μm. Is preferred.
The specific gravity of each particle 5a, 5b is preferably set to be approximately equal to the specific gravity of the liquid phase dispersion medium 6. Thereby, each particle 5a, 5b can stay in a fixed position in the liquid phase dispersion medium 6 for a long time even after the application of the voltage between the electrodes 3, 4 is stopped. That is, the information displayed on the electrophoretic display device 20 is held for a long time.

  For the liquid phase dispersion medium 6, an insulating liquid is used. Examples of such 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, Esters such as ethyl acetate, butyl acetate and ethyl formate, ketones such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, methyl isopropyl ketone and cyclohexanone, and aliphatic hydrocarbons such as pentane, hexane and octane (paraffinic) Hydrocarbons), cycloaliphatic hydrocarbons such as cyclohexane, methylcyclohexane, benzene, toluene, xylene, hexylbenzene, hebutylbenzene, octylbenzene, nonylben , Aromatic hydrocarbons such as benzenes (alkylbenzene derivatives) with long-chain alkyl groups such as decylbenzene, undecylbenzene, dodecylbenzene, tridecylbenzene, tetradecylbenzene, methylene chloride, chloroform, carbon tetrachloride 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- Examples include amides such as dimethylformamide and N, N-dimethylacetamide, carboxylates, and other various oils, 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.

In such an electrophoretic display device 20, when a voltage is applied between the first electrode 3 and the second electrode 4, according to the electric field generated between them, the inorganic particles 5a and the resin particles 5b are respectively Electrophoresis towards either electrode.
For example, in the case of using positively charged inorganic particles 5a and negatively charged resin particles 5b, if the second electrode 4 is set to a positive potential, as shown in FIG. The resin particles 5b move to the second electrode 4 side and gather on the second electrode 4 while moving to the first electrode 3 side and gathering 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 inorganic particles 5a can be seen.

On the other hand, when the second electrode 4 is set to a negative potential, the inorganic particles 5a move to the second electrode 4 side and move onto the second electrode 4 as shown in FIG. On the other hand, the resin particles 5 b move to the first electrode 3 side and 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 resin particles 5b can be seen.
Therefore, the display of the electrophoretic display device 20 is appropriately set by turning on / off the voltage application between each second electrode 4 and the first electrode 3 and appropriately setting the polarity of the second electrode 4. On the surface side, desired information (image) is displayed by a combination of the color of the inorganic particles 5a and the color of the resin particles 5b (the display content can be freely changed).

When the electrophoretic dispersion liquid 10 in which one type of electrophoretic particle is dispersed in the liquid phase dispersion medium 6 is used, for example, when the electrophoretic particle having a positive charge is used, When the electrode 4 is set to a positive potential, the electrophoretic particles move to the first electrode 3 side and 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 can be seen.
On the contrary, when the second electrode 4 is set to a negative potential, the electrophoretic particles move to the second electrode 4 side and gather on the second electrode 4. 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.

The binder material 41 is, for example, for the purpose of bonding the first substrate 1 and the second substrate 2, for the purpose of fixing the first substrate 1 and the second substrate 2 and the microcapsule 40, and between the electrodes 3 and 4. Supplied for the purpose of ensuring insulation. Thereby, durability and reliability of the electrophoretic display device 20 can be further improved.
For the binder material 41, a resin material that is excellent in affinity (adhesion) with the electrodes 3 and 4 and the capsule body 401 (microcapsule 40) and excellent in insulation is preferably used.

Such a binder material 41 is not particularly limited. For example, polyethylene, chlorinated polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, polypropylene, ABS resin, methyl methacrylate resin, Vinyl chloride resin, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride acrylate copolymer, vinyl chloride-methacrylic acid copolymer, vinyl chloride-acrylonitrile copolymer, ethylene- Vinyl alcohol-vinyl chloride copolymer, propylene-vinyl chloride copolymer, vinylidene chloride resin, vinyl acetate resin, polyvinyl alcohol, polyvinyl formal, cellulose resin and other thermoplastic resins, polyamide resin, polyacetal, polycarbonate, polyethylene Polymers such as terephthalate, polybutylene terephthalate, polyphenylene oxide, polysulfone, polyamideimide, polyaminobismaleimide, polyethersulfone, polyphenylenesulfone, polyarylate, grafted polyphenylene ether, polyetheretherketone, polyetherimide, polytetrafluoride Fluorine-based resins such as ethylene, polyfluorinated ethylene propylene, tetrafluoroethylene-perfluoroalkoxyethylene copolymer, ethylene-tetrafluoroethylene copolymer, polyvinylidene fluoride, polytrifluoroethylene chloride, fluororubber, silicone Resin, silicone resin such as silicone rubber, and others, methacrylic acid-styrene copolymer, polybutylene, methyl methacrylate-butadiene-styrene copolymer, etc. It is, can be used singly or in combination of two or more of them.
The binder material 41 is preferably set so that the dielectric constant thereof is substantially equal to the dielectric constant of the liquid phase dispersion medium 6. For this reason, it is preferable to add a dielectric constant adjusting agent such as alcohols such as 1,2-butanediol and 1,4-butanediol, ketones, and carboxylates to the binder material 41.

In the present invention, the electrophoretic display device 20 has a plurality of display areas having different display colors.
In the present embodiment, as shown in FIG. 3, the electrophoretic display device 20 includes a first display area 81 and a second display area 82 that have different display colors. That is, the display area 80 is divided (segmented) into a first display area 81 and a second display area 82. The first display area 81 and the second display area 82 may be continuous or discontinuous.

In a portion corresponding to the first display area 81, for example, white and a first color (for example, red, green, blue, black, etc.) different from white are displayed (switching between white and the first color). The microcapsule 40 that can be) is disposed.
On the other hand, in the portion corresponding to the second display area 82, for example, white and a display of white and a second color different from the first color (for example, red, green, blue, black, etc.) A microcapsule 40 capable of switching to the second color is provided.
Therefore, as described above, desired information (image) is displayed in the first display area 81 by a combination of white and the first color (the display content can be freely changed). Similarly, desired information is displayed in the second display area 82 by a combination of white and the second color.

Next, an example of a method for manufacturing the electrophoretic display device 20 will be described.
[1] Step of supplying microcapsule dispersion First microcapsule dispersion containing microcapsules 40 capable of displaying the first color, binder material 41, and a dispersion medium (particularly an aqueous solvent), A microcapsule 40 capable of displaying the second color, a binder material 41, and a second microcapsule dispersion liquid containing a dispersion medium (particularly an aqueous solvent) are prepared.
Then, the first microcapsule dispersion is applied to the portion corresponding to the first display region 81 on the second substrate 2 (on the second electrode 4), and the average particle size of the microcapsules 40 is applied (thickness of application). Supply so that it may become substantially the same diameter, and form a coating film. With such a thickness, the microcapsules 40 can be disposed on the second substrate 2 as a single layer.

Similarly, the second microcapsule dispersion is applied to the portion corresponding to the second display region 82 on the second substrate 2 (on the second electrode 4), and the thickness (coating thickness) is an average of the microcapsules 40. Supply so that it may become substantially the same as a particle size, and form a coating film.
The method for supplying each microcapsule dispersion is not particularly limited, and examples thereof include a doctor blade method, a wire bar coating method, and a roll coating method.
Each microcapsule dispersion may be supplied onto the first substrate 1.

[2] Bonding Step of First Substrate 1 and Second Substrate 2 Next, the first substrate 1 is subjected to a second step so that the first electrode 3 faces the coating film of each microcapsule dispersion. As shown in FIG. 1, the first substrate 1 and the second substrate 2 are joined to each other with the microcapsules 40 interposed therebetween.
The bonding of the first substrate 1 and the second substrate 2 is performed using the binder material in the coating film (microcapsule dispersion) as an adhesive. That is, the coating film is dried, and the dispersion medium in the coating film is volatilized and removed.
In addition, the bonding method of the 1st board | substrate 1 and the 2nd board | substrate 2 is not restricted to this, For example, the 1st board | substrate 1 and the 2nd board | substrate 2 are separately used, for example using a predetermined adhesive agent separately. May be joined.

As described above, in the electrophoretic display device 20, the first display area 81 and the second display area 82 display in different colors. For example, the first display area 81 is classified according to the purpose. By properly using the second display area 82, the persuasiveness and the visibility of the display contents in each of them are improved. In particular, it is very effective when used in a bright place such as daytime.
The electrophoretic display device 20 can be applied to, for example, a signboard. In this case, the display contents such as characters can be arbitrarily changed in each display area, and thus can be used as various signs.

  In the present embodiment, the number of display areas is two. However, the present invention is not limited to this, and may be three or more. When there are three or more display areas, the display colors may be different from each other in all of the display areas (there may be no display area of the same display color), or the same display color. There may be a combination of display areas. In other words, the display colors need only be different from each other in at least two display areas.

  In this embodiment, the microcapsules are arranged so as to straddle two adjacent pixel electrodes (electrodes). However, in the present invention, the invention is not limited to this, and, for example, three or more microcapsules are adjacent to each other. May be arranged so as to straddle the pixel electrodes of each other, may be arranged so as not to straddle the adjacent pixel electrodes, and may be a microcapsule that does not straddle the adjacent pixel electrodes, May be mixed.

In this embodiment, one microcapsule is arranged for two pixel electrodes. However, the present invention is not limited to this. For example, one microcapsule is arranged for one pixel electrode. In addition, a plurality of microcapsules may be arranged for one pixel electrode, and one microcapsule may be arranged for three or more pixel electrodes.
In addition, the present embodiment is of a microcapsule type. However, in the present invention, the form of the electrophoretic display device is not limited to this, for example, between the first substrate 1 and the second substrate 2. The electrophoresis dispersion liquid may be provided directly as the electrophoresis dispersion liquid layer.

Second Embodiment
Next, a second embodiment of the electrophoretic display device of the present invention will be described.
Hereinafter, the electrophoretic display device of the second embodiment will be described. However, the description will focus on the differences from the electrophoretic display device of the first embodiment, and the description of the same matters will be omitted.
In the electrophoretic display device 20 of the second embodiment, the display contents are constant in each of the plurality of display areas (the first display area 81 and the second display area 82 in the present embodiment). This is the same as the electrophoretic display device 20 of the first embodiment except that it cannot be changed.
That is, in the electrophoretic display device 20, predetermined information (image) set in advance is displayed in each of the first display area 81 and the second display area 82, and selection between display and non-display is performed. Only (display on / off) is configured.

The display patterns (display contents) in the first display area 81 and the second display area 82 are, for example, the arrangement pattern of the microcapsules 40, the pattern (shape) of the first electrode 3, and the second electrode 4, respectively. It can be set as desired by setting one or more of the patterns (shapes).
Also by the electrophoretic display device 20 of the second embodiment, the same effect as that of the first embodiment can be obtained.

Note that the electrophoretic display device 20 of the second embodiment can be modified in various ways as described in the first embodiment.
Moreover, in this invention, you may provide the 1 or several display area where display content is constant, and the 1 or several display area which can change display content.
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.

<< Price tag >>
First, an embodiment when the electronic apparatus of the present invention is suitable for a price tag will be described.
FIG. 4 is a plan view showing an embodiment when the electronic device of the present invention is applied to a price tag.
A price tag 100 shown in FIG. 4 includes a main body 101 provided with an operation unit (not shown) and a display unit 102. The display unit 102 is configured by the electrophoretic display device 20 of the first embodiment described above.
The product name is displayed in black, for example, in the first display area 81 of the display unit 102, and the amount of money is displayed in red, for example, in the second display area 82. These product names and prices can be arbitrarily changed by the operation unit. For this reason, for example, in the case of a bargain sale, there is an advantage that the amount can be changed by a simple operation.

<< Smart card >>
Next, an embodiment when the electronic apparatus of the present invention is suitable for a smart card will be described.
FIG. 5 is a plan view showing an embodiment when the electronic apparatus of the present invention is applied to a smart card.

A smart card 200 shown in FIG. 5 is applied to a point card, and includes a main body 201 provided with an input unit (not shown) and a display unit 202. The display unit 202 is configured by the electrophoretic display device 20 of the first embodiment described above.
The display unit 202 is installed at the upper right of the main body 201 in FIG. In addition, a store name is provided (described) in the lower right of the main body 201 in FIG.
In the first display area 81 of the display unit 202, the name of the owner is displayed in black, for example, and in the second display area 82, points are displayed in red, for example. The names and points of these owners can be arbitrarily changed by signals from the input unit.

<< Display panel in use >>
Next, an embodiment in which the electronic apparatus of the present invention is suitable for a display board in use will be described.
FIG. 6 is a plan view showing an embodiment in which the electronic apparatus of the present invention is applied to a display panel in use.

A display board 300 shown in FIG. 6 shows, for example, a use state (usage state) of a room (room) such as a conference room, and includes a main body 301 provided with an operation unit (not shown), a display unit 302, and the like. It has. The display unit 302 is configured by the electrophoretic display device 20 of the second embodiment described above.
In the first display area 81 of the display unit 302, “vacant” is displayed in black, for example, and “in use” is displayed in red in the second display area 82, for example. The display of “vacant” and “in use” can be switched by the operation unit.

Note that the electronic device of the present invention is not limited to the application as described above, and examples thereof include a signal, a calendar, a clock, and the like. The electrophoretic display device 20 can be applied.
As described above, the electrophoretic display device and the electronic apparatus according to the present invention have been described based on the illustrated embodiment. However, the present invention is not limited to this, and the configuration of each unit is an arbitrary configuration having the same function Can be substituted. In addition, any other component may be added to the present invention.

Further, the present invention may be a combination of any two or more configurations (features) of the above embodiments.
Moreover, although the said embodiment showed about the thing of the structure provided with one pair of electrodes facing, this invention is not restricted to this, For example, the thing of the structure which provides a pair of electrodes on the same board | substrate It can also be applied to.
Moreover, although the said embodiment showed about the thing of the structure provided with one pair of board | substrates facing, this invention is not limited to this, For example, it can also apply to what has a single board | substrate. .

Next, specific examples of the present invention will be described.
<Preparation of microcapsules>
First, titania particles (made by Ishihara Sangyo Co., Ltd.) surface-treated with a titania-based coupling agent (trade name KR-TTS manufactured by Ajinomoto Co., Inc.) and an aluminum-based coupling agent (trade name AL-M manufactured by Ajinomoto Co., Inc.), dodecylbenzene (Kanto) An electrophoretic dispersion medium was prepared by adding and dispersing acrylic resin particles (average particle diameter: 4 μm) (manufactured by Soken Chemical Co., Ltd.), which were dispersed in black) and further dispersed in black.
This electrophoretic dispersion medium was dropped into a solution in which arabic gum and gelatin were dissolved and stirred. In addition, the rotational speed of stirring is 1300 rpm.

  Next, the pH of the solution was adjusted to 3.7 with acetic acid, and then capsules were precipitated by cooling with ice. Further, formaldehyde was added to form a crosslinked structure in the capsule. After that, after stirring all day and night, classification is performed to classify the microcapsules that can be displayed in white and black (switching between white and black) with a particle size of 50 to 60 μm (hereinafter simply referred to as “black and white microcapsules”). Say).

  Similarly, a microcapsule capable of displaying white and red (switching between white and red) (hereinafter simply referred to as “red-white microcapsule”) and a display of white and green (white and red). A microcapsule capable of switching between green (hereinafter simply referred to as “green-white microcapsule”) and a microcapsule capable of displaying white and blue (switching between white and blue) (hereinafter simply referred to as “ Blue and white microcapsules ”) were prepared.

<Preparation of microcapsule dispersion>
For each of the various microcapsules produced, each microcapsule was mixed with a water-based emulsion type binder material (“Polon” manufactured by Shin-Etsu Chemical Co., Ltd.). Prepared.

(Example 1)
A second substrate made of polyethylene terephthalate on which a second electrode made of ITO was formed was prepared.
Then, a microcapsule dispersion having black and white microcapsules was applied to a portion corresponding to the first display region 81 on the second substrate by a doctor blade method to form a coating film having a thickness of 60 μm.
In addition, a microcapsule dispersion having red and white microcapsules was applied to a portion corresponding to the second display region 82 on the second substrate by a doctor blade method to form a coating film having a thickness of 60 μm. .
After coating, the coating film was dried at 90 ° C. for 10 minutes.
Next, using a laminator, the first substrate made of polyethylene terephthalate on which the first electrode made of ITO is formed is stacked on the second substrate so that the first electrode faces the coating film, The substrate and the second substrate were bonded to each other. The electrophoretic display device shown in FIG. 1 similar to that of the first embodiment was manufactured through the above steps.

(Example 2)
Supplying the microcapsule dispersion liquid having black and white microcapsules and the microcapsule dispersion liquid having red and white microcapsules in Example 1 so as to correspond to a certain display pattern (display contents) (coating film) The electrophoretic display device shown in FIG. 1 was produced in the same manner as in Example 1 except that the electrode pattern was changed.
[Evaluation]
When the electrophoretic display devices produced in Examples 1 and 2 were each displayed, the persuasiveness and visibility of the display contents were very good.

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 a top view of the electrophoretic display device shown in FIG. It is a top view which shows embodiment at the time of applying the electronic device of this invention to a price tag. It is a top view which shows embodiment at the time of applying the electronic device of this invention to a smart card. It is a top view which shows embodiment at the time of applying the electronic device of this invention to the display board of use condition. 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 5a, 5b ... Electrophoretic particle 6 ... Liquid phase dispersion medium 7 ... Spacer 71 ... Sealed space 10 ... Electrophoretic dispersion 20 ... Electrophoretic display device 40 ... Microcapsule 401 ... Capsule body 41 ... Binder material 80 ... Display area 81 ... First display area 82 ... Second Display area 100 ... price tag 101 ... main body 102 ... display unit 200 ... smart card 201 ... main body 202 ... display unit 300 ... display board 301 ... main body 302 ... display unit 903 ... first electrode 904 2nd electrode 905 Electrophoretic particles 906 Liquid phase dispersion medium 920 Electrophoretic display device

Claims (9)

An electrophoretic display device comprising an electrode, a substrate, and an electrophoretic dispersion layer provided on the substrate and having an electrophoretic dispersion liquid containing at least one kind of electrophoretic particles,
An electrophoretic display device comprising a plurality of display areas having different display colors. An electrophoretic display device comprising: an electrode; a pair of opposing substrates; and an electrophoretic dispersion layer provided between the pair of substrates and having an electrophoretic dispersion containing at least one kind of electrophoretic particles. There,
An electrophoretic display device comprising a plurality of display areas having different display colors.   3. The electrophoretic display device according to claim 1, wherein display contents can be changed in at least one of the plurality of display areas. 4.   The electrophoretic display device according to claim 1, wherein display content is constant in at least one of the plurality of display areas.   The electrophoretic display device according to claim 1, wherein the electrophoretic dispersion layer is configured by arranging a plurality of microcapsules encapsulating the electrophoretic dispersion.   6. The electrophoretic display device according to claim 1, wherein in each of the display regions, a plurality of types of electrophoretic particles having different characteristics are used as the electrophoretic particles.   6. The electrophoretic display device according to claim 1, wherein at least two types of electrophoretic particles having different colors and charging polarities are used as the electrophoretic particles in each display region.   In each of the display regions, as the electrophoretic particles, at least inorganic particles, and resin particles that are colored in a color different from the color of the inorganic particles and have a charging polarity opposite to the charging polarity of the inorganic particles, The electrophoretic display device according to claim 1, wherein the electrophoretic display device is used.   An electronic apparatus comprising the electrophoretic display device according to claim 1.

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