JP2009186731A - Display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display element which includes a simple construction of members, is driven with low voltage, exhibits high contrast, and produces little fluctuation of reflectance in repeated driving. <P>SOLUTION: The display element is characterized in that: it includes an electrolyte between mutually facing electrodes; at least one of the mutually facing electrodes includes a porous layer composed of a metal oxide; both a metal salt compound and an electrochromic compound are fixed to the porous layer; and black, white, and a color other than black are displayed by a driving operation of the facing electrodes. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a novel electrochemical display element.

  In recent years, with the increase in the operating speed of personal computers, the spread of network infrastructure, the increase in capacity and price of data storage, etc., information such as documents and images conventionally provided in printed materials such as paper has become easier. Opportunities to obtain and view electronic information are increasing.

  As a means for browsing such electronic information, conventional liquid crystal displays and CRTs (CRTs), and in recent years, light-emitting types such as organic electroluminescence displays are mainly used. In particular, when electronic information is document information, It is necessary to keep a close eye on this browsing means for a relatively long time, and these actions are not necessarily human-friendly means. Generally, as a disadvantage of the light-emitting display, flickering makes the eyes tired, inconvenient to carry, read There are known problems such as the posture being restricted and the need to adjust the line of sight to the still screen, and the increased power consumption when read for a long time.

  As a display means to compensate for these drawbacks, a reflection type display having a so-called memory property that uses external light and does not consume power for image retention is known. However, it has sufficient performance for the following reasons. It's hard to say.

  For example, a method using a polarizing plate such as a reflective liquid crystal has a low reflectance of about 40% and is difficult to display white, and many of the manufacturing methods used for producing the constituent members are not easy. In addition, the polymer dispersed liquid crystal requires a high voltage and utilizes the difference in refractive index between organic substances, so that the resulting image has insufficient contrast. In addition, the polymer network type liquid crystal has problems such as a high voltage and a complicated TFT circuit required to improve the memory performance. In addition, a display element based on electrophoresis requires a high voltage of 10 V or more, and there is a concern about durability due to electrophoretic particle aggregation. As a method for performing color display using these methods, a method using a color filter is known. In principle, a bright white display cannot be obtained due to the coloring of the color filter.

  As a method capable of full color display that can be driven at a low voltage, an electrochromic method (see, for example, Patent Document 1) is known. The electrochromic method can be driven at a low voltage of 3 V or less, but when displaying full color, it is necessary to laminate three layers of different colors, and there is a concern about high cost due to a complicated element configuration. A full-color electrochromic device using flat ground mixing (see, for example, Patent Document 2) is known. However, in this method, black display contrast is not sufficient because of flat ground mixing, and therefore a method of performing color display and black display in a single layer. Is desired.

As a result of examining the techniques disclosed in these patent documents in detail, the present inventor has found that there is a problem in the stability of reflectance when it is repeatedly driven, and the requirement specification of users has increased in recent years. It has been found that further improvements are necessary to meet the requirements.
Special table 2001-510590 gazette JP 2003-270670 A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a display element that can be driven with a simple member configuration, low voltage, exhibits high contrast, and has little fluctuation in reflectance during repeated driving. There is to do.

  The above object of the present invention is achieved by the following configurations.

  1. The counter electrode has an electrolyte, and at least one of the counter electrodes has a porous layer made of a metal oxide, and both the metal salt compound and the electrochromic compound are immobilized on the porous layer. A display element that performs black display, white display, and color display other than black by driving the counter electrode.

  2. 2. The porous layer is composed of metal oxide particles, and the metal oxide particles are metal oxide particles in which a metal salt compound and an electrochromic compound are immobilized in advance. Display element.

  3. 3. The display element according to 1 or 2 above, wherein the metal salt compound is a silver salt compound.

  4). 4. The display element according to any one of 1 to 3, wherein the electrochromic compound is a compound represented by the following general formula (A).

[Wherein, R ¹ represents a substituted or unsubstituted aryl group, and R ² and R ³ each represent a hydrogen atom or a substituent. X represents> N—R ⁴ , an oxygen atom or a sulfur atom, and R ⁴ represents a hydrogen atom or a substituent. ]
5. 5. The display element according to any one of 1 to 4, wherein the metal salt compound is a salt of a compound represented by the following general formula (1) and a metal.

Formula (1) R ₁ -L-SM
[Wherein R ₁ represents —COOH, —P═O (OH) ₂ , —OP═O (OH) ₂ or —Si (OR) ₃ (R represents an alkyl group), and L represents Represents a linking group, and M represents a hydrogen atom, a metal atom or quaternary ammonium. ]
6). 6. The display element according to 5 above, wherein a metal salt compound is formed after immobilizing the compound represented by the general formula (1) on the porous layer.

7). The compound represented by the general formula (A) is —COOH, —P═O (OH) ₂ , —OP═O (OH) ₂ or —Si (OR) ₃ (R represents an alkyl group.) The display element according to any one of 1 to 6 above, wherein

  8). 8. The display element according to any one of 1 to 7, wherein the electrolyte contains a compound represented by the following general formula (III) or (IV).

[Wherein, L represents an oxygen atom or CH ₂ , and R ^{8 to} R ¹¹ each represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group, or an alkoxy group. ]

[Wherein, R ¹² and R ¹³ each represent a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group or an alkoxy group. ]

  According to the present invention, it is possible to provide a display element that has a simple member configuration, can be driven at a low voltage, exhibits high contrast, and has little fluctuation in reflectance during repeated driving.

  Hereinafter, the best mode for carrying out the present invention will be described in detail.

  As a result of intensive studies in view of the above problems, the inventor has an electrolyte between the counter electrodes, and at least one of the counter electrodes has a porous layer made of a metal oxide. The display element is characterized in that both the metal salt compound and the electrochromic compound are immobilized on the material layer, so that the oxidation-reduction reaction of the metal salt compound and the oxidation-reduction reaction of the electrochromic compound occur at a certain site. As a result, the present inventors have found that a display element that can be driven with a simple member configuration, low voltage, exhibits high contrast, and has little fluctuation in reflectance by repeated driving can be realized.

  Details of the present invention will be described below.

[Basic structure of display element]
In the display element of the present invention, the display portion is provided with one corresponding counter electrode. A transparent electrode such as an ITO electrode having a porous layer made of a metal oxide is provided on the electrode 1 which is one of the counter electrodes close to the display portion, and a conductive electrode is provided on the other electrode 2. The electrode 1 is fixed with both the metal salt compound and the electrochromic compound according to the present invention, and the electrolyte according to the present invention is held between the electrode 1 and the electrode 2, and more preferably, The metal salt compound according to the present invention is a silver salt compound, and the electrochromic compound is a compound represented by the general formula (A). By applying a voltage of positive and negative polarity between the counter electrodes, a metal dissolution and precipitation reaction and an electrochromic reaction of an electrochromic compound are performed, and the colored states other than black, white, and black can be switched reversibly. .

[Immobilization of metal salt compounds and electrochromic compounds]
The display element of the present invention is characterized in that both a metal salt compound and an electrochromic compound are immobilized on a porous layer.

The immobilization method according to the present invention comprises a functional group such as —COOH, —P═O (OH) ₂ , —OP═O (OH) ₂ or —Si (OR) ₃ , a metal salt compound and an electrochromic compound. By adsorbing to the surface of the metal oxide, a method of adsorbing to the surface of the metal oxide constituting the porous layer, a method of chemically bonding to the surface of the metal oxide, a metal salt compound or an electrochromic compound together with a polymer binder in an appropriate solvent. Dissolve and place the resulting liquid on the porous layer by coating method, ink jet method, dipping method, spin coating method, etc., and heat or photocrosslink polymer binders as needed, metal salt compound or electro Dissolve the chromic compound in a suitable solvent, place the resulting liquid on the porous layer by coating method, ink jet method, dipping method, spin coating method, etc. Examples include a method in which a solvent in which a metal salt compound or an electrochromic compound is practically insoluble is used as an electrolyte solvent.

The preferred immobilization method according to the present invention comprises a functional group such as —COOH, —P═O (OH) ₂ , —OP═O (OH) _2, or —Si (OR) ₃ with a metal salt compound and an electrochromic compound. It is the method of making it adsorb | suck to the metal oxide surface which comprises a porous layer, or making it chemically bond with the metal oxide surface.

  The porous layer forming method according to the present invention comprises forming a porous layer made of a metal oxide on a transparent electrode, and applying the metal salt compound and the electrochromic compound to the obtained porous layer by any of the methods described above. A method of fixing both, forming a first porous layer made of a metal oxide (hereinafter referred to as a first porous layer) on a transparent electrode, and obtaining one of the above-mentioned on the obtained first porous layer Either one of the metal salt compound and the electrochromic compound is fixed by the above method, and a second porous layer (hereinafter referred to as second porous layer) is formed on the first porous layer. Method of immobilizing compound that is not immobilized on first porous layer among compound or electrochromic compound in second porous, metal salt compound on metal oxide fine particles before forming porous layer And electrochromic compounds described above It was immobilized by any method, and a method in which a metal salt compound obtained and electrochromic compound to form a porous layer by using the immobilized metal oxide particles.

[Porous layer made of metal oxide]
A porous layer made of a metal oxide used in the display element of the present invention will be described below.

  In the present invention, the term “porous” means that a porous layer is disposed, a potential difference is applied between the counter electrodes, and an oxidation-reduction reaction of an electrochromic compound or a dissolution and precipitation reaction of a metal can be caused. The penetration state that can move in the electrode.

  Examples of the metal oxide constituting the porous layer according to the present invention include titanium oxide, silicon oxide, zinc oxide, tin oxide, Sn-doped indium oxide (ITO), antimony-doped tin oxide (ATO), and fluorine-doped tin oxide. (FTO), aluminum-doped zinc oxide and the like, or a mixture thereof.

The porous layer is formed by binding or contacting a plurality of fine particles of the metal oxide. The average particle diameter of the metal oxide fine particles is preferably 5 nm to 10 μm, more preferably 20 nm to 1 μm. The specific surface area of the metal oxide fine particles is preferably ^{1 × 10 -3 ~1 × 10 2} m 2 / g by a simple BET method, more preferably at 1 × 10 ^-2 ~10m ² / g . The metal oxide fine particles may have any shape such as an indefinite shape, a needle shape, or a spherical shape.

  As a method for forming or binding metal oxide fine particles, a known sol-gel method or sintering method can be employed. For example, 1) Journal of the Ceramic Society of Japan, 102, 2, p200 (1994), 2 ) Ceramics Association Journal 90, 4, p157, 3) J. of Non-Cryst. Solids, 82, 400 (1986) and the like. Further, it is also possible to use a method in which titanium oxide dendrimer particles produced by a vapor phase method are dispersed on a solution and applied onto a substrate, and the solvent is removed to obtain a porous electrode. The metal oxide fine particles are preferably bound.

[Electrochromic compound]
The electrochromic compound used in the display element of the present invention may be a compound that exhibits a phenomenon (electrochromism) in which the property of optical absorption (color and light transmittance) of a substance reversibly changes due to electrochemical redox. Any compound may be used. Specific compounds include "Electrochromic display" (June 28, 1991, Sangyo Tosho Co., Ltd.) pp27-124, "Development of chromic materials" (November 15, 2000, CMC Corporation) pp81 The compound described in -95 etc. can be mentioned.

[Compound represented by formula (A)]
In the display device of the present invention, the compound represented by the general formula (A) that is suitably used as an electrochromic compound will be described.

In the general formula (A), R ¹ represents a substituted or unsubstituted aryl group, and R ² and R ³ each represent a hydrogen atom or a substituent. X represents> N—R ⁴ , an oxygen atom or a sulfur atom, and R ⁴ represents a hydrogen atom or a substituent.

In the general formula (A), specific examples of the substituent represented by R ¹ , R ² , R ³ include, for example, an alkyl group (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group). , Pentyl group, hexyl group, etc.), cycloalkyl group (eg, cyclohexyl group, cyclopentyl group, etc.), alkenyl group, cycloalkenyl group, alkynyl group (eg, propargyl group, etc.), glycidyl group, acrylate group, methacrylate group, aromatic Group (eg, phenyl, naphthyl, anthracenyl, etc.), heterocyclic (eg, pyridyl, thiazolyl, oxazolyl, imidazolyl, furyl, pyrrolyl, pyrazinyl, pyrimidinyl, pyridazinyl, selenazolyl) Group, sliphoranyl group, piperidinyl group, pyrazolyl group, tetrazoli group Group), alkoxy group (eg methoxy group, ethoxy group, propyloxy group, pentyloxy group, cyclopentyloxy group, hexyloxy group, cyclohexyloxy group etc.), aryloxy group (eg phenoxy group etc.), alkoxycarbonyl Group (for example, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, etc.), aryloxycarbonyl group (for example, phenyloxycarbonyl group, etc.), sulfonamide group (for example, methanesulfonamide group, ethanesulfonamide group) , Butanesulfonamide group, hexanesulfonamide group, cyclohexanesulfonamide group, benzenesulfonamide group, etc.), sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group) Group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, phenylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), urethane group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido) Group, phenylureido group, 2-pyridylureido group etc.), acyl group (eg acetyl group, propionyl group, butanoyl group, hexanoyl group, cyclohexanoyl group, benzoyl group, pyridinoyl group etc.), carbamoyl group (eg amino Carbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, phenylaminocarbonyl group, 2-pyridyl Aminocarbonyl group etc.), acylamino group (eg acetylamino group, benzoylamino group, methylureido group etc.), amide group (eg acetamido group, propionamide group, butanamide group, hexaneamide group, benzamide group etc.), sulfonyl Group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, phenylsulfonyl group, 2-pyridylsulfonyl group, etc.), sulfonamide group (for example, methylsulfonamide group, octylsulfonamide group, phenylsulfone) Amide group, naphthylsulfonamide group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, anilino group, 2-pyridylamino group, etc.), halogen atom For example, chlorine atom, bromine atom, iodine atom, etc.), cyano group, nitro group, sulfo group, carboxyl group, hydroxyl group, phosphono group (for example, phosphonoethyl group, phosphonopropyl group, phosphonooxyethyl group), oxamoyl group Etc. Further, these groups may be further substituted with these groups.

R ¹ is a substituted or unsubstituted aryl group, preferably a substituted or unsubstituted phenyl group, more preferably a substituted or unsubstituted 2-hydroxyphenyl group or 4-hydroxyphenyl group.

R ² and R ³ are preferably an alkyl group, a cycloalkyl group, an aromatic group, or a heterocyclic group, more preferably one of R ² and R ³ is a phenyl group, the other is an alkyl group, and more preferably R ² and R ³ are both phenyl groups.

X is preferably> N—R ⁴ . R ⁴ is preferably a hydrogen atom, an alkyl group, an aromatic group, a heterocyclic group, or an acyl group, more preferably a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 5 to 10 carbon atoms, or acyl. It is a group.

  Specific examples of the electrochromic compound represented by the general formula (A) are shown below, but the present invention is not limited to these compounds.

In the display device of the present invention, the compound represented by the general formula (A) according to the present invention contains —COOH, —PO (OH) ₂ , —OP═O (OH) ₂ or — It preferably has Si (OR) ₃ (R represents an alkyl group).

[Metal salt compounds]
The metal salt compound according to the present invention is fixed to a porous layer made of a metal oxide. The metal salt compound is dissolved and dissolved on at least one electrode on the counter electrode by a driving operation of the counter electrode. Any compound may be used as long as it contains a metal species that can be precipitated. Preferred metal species are silver, bismuth, copper, nickel, iron, chromium, zinc and the like, and particularly preferred are silver and bismuth.

[Silver salt compound]
In the display element according to the present invention, the metal salt compound is preferably a silver salt compound.

  The silver salt compound according to the present invention is silver or a compound containing silver in the chemical structure, such as silver oxide, silver sulfide, metallic silver, silver colloidal particles, silver halide, silver complex compound, silver ion and the like. It is a generic term, and there are no particular limitations on the state species of the phase such as the solid state, the solubilized state in liquid, and the gas state, and the charged state species such as neutral, anionic, and cationic.

[Compound represented by the general formula (1)]
The metal salt compound according to the present invention is preferably a salt of a compound represented by the general formula (1) and a metal.

  The compound represented by the general formula (1) according to the present invention will be described below.

In the general formula (1), R ₁ represents —COOH, —P═O (OH) ₂ , —OP═O (OH) ₂ or —Si (OR) ₃ (R represents an alkyl group).

In general formula (1), M represents a hydrogen atom, a metal atom, or quaternary ammonium. Examples of the metal atom represented by M include Li, Na, K, Mg, Ca, Zn, Ag, and the like. Examples of the quaternary ammonium include NH ₄ , N (CH ₃ ) ₄ , N ( C ₄ H ₉ ) ₄ , N (CH ₃ ) ₃ C ₁₂ H ₂₅ , N (CH ₃ ) ₃ C ₁₆ H ₃₃ , N (CH ₃ ) ₃ CH ₂ C ₆ H _{5 and the} like.

  In the general formula (1), L represents a linking group, and the linking group may be any group such as an alkyl group, a phenyl group, a heterocyclic group, etc., as long as the group connects SM and R1 in the general formula (1). A preferable group is a nitrogen-containing heterocyclic ring, and examples of the nitrogen-containing heterocyclic ring include a tetrazole ring, a triazole ring, an imidazole ring, an oxadiazole ring, a thiadiazole ring, an indole ring, an oxazole ring, a benzoxazole ring, and a benzine. Examples include an imidazole ring, a benzothiazole ring, a benzoselenazole ring, and a naphthoxazole ring.

  Next, although the preferable specific example of a compound represented by General formula (1) is shown, this invention is not limited to these compounds.

  Among the above-exemplified compounds, Exemplified Compounds 1-13 to 1-16 are particularly preferable from the viewpoint that the object and effects of the present invention can be exhibited.

[Compound represented by general formula (III) or general formula (IV)]
In the display element of the present invention, the electrolyte preferably contains a compound represented by the general formula (III) or (IV).

  First, details of the compound represented by formula (III) will be described.

In the general formula (III), L represents an oxygen atom or CH ₂ , and R ^{8 to} R ¹¹ each represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group, or an alkoxy group.

  Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, tert-butyl, pentyl, hexyl, octyl, dodecyl, tridecyl, tetradecyl, pentadecyl, and the like as aryl groups. Examples of the cycloalkyl group such as phenyl group, naphthyl group and the like include, for example, a cyclopentyl group, cyclohexyl group and the like, an alkoxyalkyl group, for example, a β-methoxyethyl group, a γ-methoxypropyl group and the like, as an alkoxy group, Examples thereof include a methoxy group, an ethoxy group, a propyloxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, and a dodecyloxy group.

  Specific examples of the compound represented by the general formula (III) are shown below, but the present invention is not limited to these compounds.

  Next, details of the compound represented by formula (IV) will be described.

In the general formula (IV), R ¹² and R ¹³ each represent a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group or an alkoxy group.

  Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, tert-butyl, pentyl, hexyl, octyl, dodecyl, tridecyl, tetradecyl, pentadecyl, and the like as aryl groups. Examples of the cycloalkyl group such as phenyl group, naphthyl group and the like include, for example, a cyclopentyl group, cyclohexyl group and the like, an alkoxyalkyl group, for example, a β-methoxyethyl group, a γ-methoxypropyl group and the like, as an alkoxy group, Examples thereof include a methoxy group, an ethoxy group, a propyloxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, and a dodecyloxy group.

  Specific examples of the compound represented by the general formula (IV) are shown below, but the present invention is not limited to these compounds.

  Among the compounds represented by the general formula (III) and the general formula (IV) exemplified above, the exemplified compounds (III-1), (IV-2) and (IV-3) are particularly preferable.

  The compounds represented by the general formulas (III) and (IV) according to the present invention are one kind of electrolyte solvents. However, in the display element of the present invention, another solvent is used as long as the object effects of the present invention are not impaired. Can be used together. Specifically, tetramethylurea, sulfolane, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, 2- (N-methyl) -2-pyrrolidinone, hexamethylphosphortriamide, N-methylpropionamide, N, N-dimethylacetamide, N-methylacetamide, N, N dimethylformamide, N-methylformamide, butyronitrile, propionitrile, acetonitrile, acetylacetone, 4-methyl-2-pentanone, 2-butanol, 1-butanol, 2 -Propanol, 1-propanol, ethanol, methanol, acetic anhydride, ethyl acetate, ethyl propionate, dimethoxyethane, diethoxyfuran, tetrahydrofuran, ethylene glycol, diethylene glycol, triethylene glycol monobuty Ether, water and the like. Among these solvents, it is preferable to include at least one solvent having a freezing point of −20 ° C. or lower and a boiling point of 120 ° C. or higher.

  Furthermore, as a solvent that can be used in the present invention, J.P. A. Riddick, W.M. B. Bunger, T.A. K. Sakano, “Organic Solvents”, 4th ed. , John Wiley & Sons (1986). Marcus, “Ion Solvation”, John Wiley & Sons (1985), C.I. Reichardt, “Solvents and Solvent Effects in Chemistry”, 2nd ed. VCH (1988), G .; J. et al. Janz, R.A. P. T.A. Tomkins, “Nonqueous Electronics Handbook”, Vol. 1, Academic Press (1972).

  In the present invention, the electrolyte solvent may be a single type or a mixture of solvents, but a mixed solvent containing ethylene carbonate is preferred. As for the addition amount of ethylene carbonate, 10-90 mass% of the total electrolyte solvent mass is preferable. A particularly preferable electrolyte solvent is a mixed solvent having a mass ratio of propylene carbonate / ethylene carbonate of 7/3 to 3/7. When the propylene carbonate ratio is larger than 7/3, the ionic conductivity is inferior and the response speed is lowered. When the propylene carbonate ratio is smaller than 3/7, the electrolyte tends to be deposited at a low temperature.

〔substrate〕
In the display element of the present invention, a substrate can be used. Examples of the substrate that can be used in the present invention include polyolefins such as polyethylene and polypropylene, polycarbonates, cellulose acetate, polyethylene terephthalate, polyethylene dinaphthalene dicarboxylate, polyethylene naphthalates, polyvinyl chloride, polyimide, and polyvinyl acetal. Synthetic plastic films such as polystyrene can also be preferably used. Syndiotactic polystyrenes are also preferred. These can be obtained, for example, by the methods described in JP-A Nos. 62-117708, 1-46912, and 1-178505. Further, a metal substrate such as stainless steel, a paper support such as baryta paper and resin coated paper, and a support provided with a reflective layer on the plastic film, supported by JP-A-62-253195 (pages 29 to 31) The thing described as a body is mentioned. RDNo. 17643, page 28, ibid. No. 18716, page 647, right column to page 648, left column, and No. 307105, page 879 can also be preferably used. As these supports, those having resistance to curling due to heat treatment of Tg or less as in US Pat. No. 4,141,735 can be used. Further, the surface of these supports may be subjected to surface treatment for the purpose of improving the adhesion between the support and other constituent layers. In the present invention, glow discharge treatment, ultraviolet irradiation treatment, corona treatment, and flame treatment can be used as the surface treatment. Furthermore, the support body described in pages 44 to 149 of publicly known technology No. 5 (issued by Aztec Co., Ltd. on March 22, 1991) can also be used. Furthermore, RDNo. 308119, page 1009, Product Licensing Index, Volume 92, P108, “Supports”, and the like. In addition, a glass substrate or an epoxy resin kneaded with glass can be used.

(Transparent conductive layer)
The display element of the present invention can have a transparent conductive layer. The transparent conductive layer is not particularly limited as long as it is transparent and conducts electricity. For example, Indium Tin Oxide (ITO: Indium Tin Oxide), Indium Zinc Oxide (IZO: Indium Zinc Oxide), Fluorine Doped Tin Oxide (FTO), Indium Oxide, Zinc Oxide, Platinum, Gold, Silver, Rhodium, Copper, Examples thereof include chromium, carbon, aluminum, silicon, amorphous silicon, and BSO (Bismuth Silicon Oxide). In order to form the electrode in this manner, for example, an ITO film may be vapor-deposited on the substrate by a sputtering method or the like, or an ITO film may be formed on the entire surface and then patterned by a photolithography method. The surface resistance value is preferably 100Ω / □ or less, and more preferably 10Ω / □ or less. The thickness of the transparent electrode is not particularly limited, but is generally 0.1 to 20 μm. Another example is a method using a conductive polymer.

[White scattered matter]
In the present invention, from the viewpoint of further increasing the display contrast and the white display reflectance, it is preferable to contain a white scattering material, and a porous white scattering layer may be formed and present.

  The porous white scattering layer applicable to the present invention can be formed by applying and drying an aqueous mixture of an aqueous polymer and a white pigment that is substantially insoluble in the electrolyte solvent.

  Examples of the white pigment applicable in the present invention include titanium dioxide (anatase type or rutile type), barium sulfate, calcium carbonate, aluminum oxide, zinc oxide, magnesium oxide and zinc hydroxide, magnesium hydroxide, magnesium phosphate, Magnesium hydrogen phosphate, alkaline earth metal salt, talc, kaolin, zeolite, acidic clay, glass, organic compounds such as polyethylene, polystyrene, acrylic resin, ionomer, ethylene-vinyl acetate copolymer resin, benzoguanamine resin, urea-formalin resin, A melamine-formalin resin, a polyamide resin, or the like may be used alone or in combination, or in a state having voids that change the refractive index in the particles.

In the present invention, among the white particles, titanium dioxide, zinc oxide, and zinc hydroxide are preferably used. In addition, titanium dioxide surface-treated with inorganic oxides (Al ₂ O ₃ , AlO (OH), SiO _2, etc.), in addition to these surface treatments, trimethylolethane, triethanolamine acetate, trimethylcyclosilane, etc. Titanium dioxide subjected to organic treatment can be used.

  Of these white particles, it is more preferable to use titanium oxide or zinc oxide from the viewpoint of coloring prevention at high temperature and the reflectance of the element due to the refractive index.

  In the present invention, examples of the water-based polymer that does not substantially dissolve in the electrolyte solvent include a water-soluble polymer and a polymer dispersed in the water-based solvent.

Examples of water-soluble compounds include proteins such as gelatin and gelatin derivatives, cellulose derivatives, natural compounds such as starch, gum arabic, dextran, pullulan, and carrageenan, and the like, polyvinyl alcohol, polyvinyl pyrrolidone, acrylamide polymers, and the like. Examples include synthetic polymer compounds such as derivatives. As gelatin derivatives, acetylated gelatin, phthalated gelatin, polyvinyl alcohol derivatives as terminal alkyl group-modified polyvinyl alcohol, terminal mercapto group-modified polyvinyl alcohol, and cellulose derivatives include hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose and the like. It is done. Further, Research Disclosure and those described on pages (71) to (75) of JP-A No. 64-13546, US Pat. No. 4,960,681, JP-A No. 62-245260, etc. superabsorbent polymers described, namely -COOM or -SO ₃ M (M is a hydrogen atom or an alkali metal) homopolymer or a vinyl monomer together or with other vinyl monomers of the vinyl monomer having a (e.g., sodium methacrylate, Copolymers with ammonium acid, potassium acrylate, etc.) are also used. Two or more of these binders can be used in combination.

  In the present invention, gelatin and gelatin derivatives, or polyvinyl alcohol or derivatives thereof can be preferably used.

  Polymers dispersed in an aqueous solvent include natural rubber latex, styrene butadiene rubber, butadiene rubber, nitrile rubber, chloroprene rubber, isoprene rubber and other latexes, polyisocyanate, epoxy, acrylic, silicone, polyurethane, Examples thereof include a thermosetting resin in which urea, phenol, formaldehyde, epoxy-polyamide, melamine, alkyd resin, vinyl resin and the like are dispersed in an aqueous solvent. Of these polymers, it is preferable to use an aqueous polyurethane resin described in JP-A-10-76621.

  In the present invention, “substantially not dissolved in an electrolyte solvent” is defined as a state in which a dissolution amount per kg of electrolyte solvent is 0 to 10 g at a temperature of −20 ° C. to 120 ° C. And the amount of dissolution can be determined by a known method such as a component quantification method using a gas chromatogram.

  In the present invention, the water mixture of the water-based compound and the white pigment is preferably in a form in which the white pigment is dispersed in water according to a known dispersion method. The mixing ratio of the aqueous compound / white pigment is preferably 1 to 0.01, more preferably 0.3 to 0.05 in terms of volume ratio.

  In the present invention, the medium for applying the water mixture of the water-based compound and the white pigment may be at any position as long as it is on the component between the counter electrodes of the display element, but on the electrode surface of at least one of the counter electrodes. It is preferable to give to. As a method for applying to a medium, for example, a coating method, a liquid spraying method, a spraying method via a gas phase, a method of flying droplets using vibration of a piezoelectric element, for example, a piezoelectric inkjet head, Examples thereof include a bubble jet (registered trademark) type ink jet head that causes droplets to fly using a thermal head that uses bumping, and a spray type that sprays liquid by air pressure or liquid pressure.

  The coating method can be appropriately selected from known coating methods. For example, an air doctor coater, blade coater, rod coater, knife coater, squeeze coater, impregnation coater, reverse roller coater, transfer roller coater, curtain coater, double coater Examples include roller coaters, slide hopper coaters, gravure coaters, kiss roll coaters, bead coaters, cast coaters, spray coaters, calendar coaters, and extrusion coaters.

  Drying of the water mixture of the aqueous compound and the white pigment applied on the medium may be performed by any method as long as water can be evaporated. For example, heating from a heat source, a heating method using infrared light, a heating method using electromagnetic induction, and the like can be given. Further, water evaporation may be performed under reduced pressure.

  Porous as used in the present invention refers to the formation of a porous white scattering material by applying a water admixture of the water-based compound and the white pigment onto the electrode and drying it, and then the silver or silver is chemically treated on the scattering material. After supplying an electrolyte solution containing the compound contained in the structure, it can be sandwiched between opposing electrodes, giving a potential difference between the opposing electrodes, causing a silver dissolution precipitation reaction, and penetrating ions that can move between the electrodes Tell the state.

  In the display element of the present invention, it is desirable to carry out a curing reaction of the water-based compound with a curing agent during or after applying and drying the water mixture described above.

  Examples of the hardener used in the present invention include, for example, U.S. Pat. No. 4,678,739, column 41, 4,791,042, JP-A-59-116655, and 62-245261. No. 61-18942, 61-249054, 61-245153, JP-A-4-218044, and the like. More specifically, aldehyde hardeners (formaldehyde, etc.), aziridine hardeners, epoxy hardeners, vinyl sulfone hardeners (N, N'-ethylene-bis (vinylsulfonylacetamide) Ethane, etc.), N-methylol hardeners (dimethylolurea, etc.), boric acid, metaboric acid or polymer hardeners (compounds described in JP-A-62-234157). When gelatin is used as the aqueous compound, it is preferable to use a vinyl sulfone type hardener or a chlorotriazine type hardener alone or in combination. Moreover, when using polyvinyl alcohol, it is preferable to use boron-containing compounds such as boric acid and metaboric acid.

  These hardeners are used in an amount of 0.001 to 1 g, preferably 0.005 to 0.5 g, per 1 g of the aqueous compound. In addition, it is possible to perform heat treatment and humidity adjustment during the curing reaction in order to increase the film strength.

(Electronic insulation layer)
In the display element of the present invention, an electrical insulating layer can be provided.

  The electronic insulating layer applicable to the present invention may be a layer having both ionic conductivity and electronic insulating properties. For example, a solid electrolyte membrane in which a polymer or salt having a polar group is formed into a film, electronic insulating properties And a porous solid body having a low relative dielectric constant such as a silicon-containing compound, and the like.

  As a method for forming a porous film, a sintering method (fusion method) (using fine pores formed between particles by adding polymer fine particles or inorganic particles to a binder or the like and partially fusing them), an extraction method ( After forming a constituent layer with a solvent-soluble organic or inorganic substance and a binder that does not dissolve in the solvent, the organic or inorganic substance is dissolved with the solvent to obtain pores), and the polymer is heated or degassed Well-known formation methods such as foaming method for foaming, phase change method for phase separation of polymer mixture by manipulating good solvent and poor solvent, and radiation irradiation method for forming pores by radiating various radiations Can be used. Specifically, JP-A-10-30181, JP-A-2003-107626, JP-B-7-95403, JP-A-2635715, JP-A-2894523, JP-A-2987474, JP-A-3066426, and JP-A-3464513. No. 3,483,464, No. 3535942, No. 30622203, and the like.

[Thickener added with electrolyte]
In the display element of the present invention, a thickener can be used for the electrolyte. For example, gelatin, gum arabic, poly (vinyl alcohol), hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate butyrate, poly ( Vinylpyrrolidone), poly (alkylene glycol), casein, starch, poly (acrylic acid), poly (methyl methacrylic acid), poly (vinyl chloride), poly (methacrylic acid), copoly (styrene-maleic anhydride), copoly ( Styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinyl acetal) s (eg, poly (vinyl formal) and poly (vinyl butyral)), poly (esters), poly (urethanes), phenoxy resins, poly (PVC Redene), poly (epoxides), poly (carbonates), poly (vinyl acetate), cellulose esters, poly (amides), hydrophobic transparent binders such as polyvinyl butyral, cellulose acetate, cellulose acetate butyrate, polyester, Examples include polycarbonate, polyacrylic acid, polyurethane and the like.

  These thickeners may be used in combination of two or more. Moreover, the compound as described in pages 71-75 of Unexamined-Japanese-Patent No. 64-13546 can be mentioned. Among these, the compounds preferably used are polyvinyl alcohols, polyvinyl pyrrolidones, hydroxypropyl celluloses, and polyalkylene glycols from the viewpoint of compatibility with various additives and improvement in dispersion stability of white particles.

[Other additives]
Examples of the constituent layers of the display element of the present invention include auxiliary layers such as a protective layer, a filter layer, an antihalation layer, a crossover light cut layer, and a backing layer. Sensitizer, noble metal sensitizer, photosensitive dye, supersensitizer, coupler, high boiling point solvent, antifoggant, stabilizer, development inhibitor, bleach accelerator, fixing accelerator, color mixing inhibitor, formalin scavenger, Toning agents, hardeners, surfactants, thickeners, plasticizers, slip agents, UV absorbers, anti-irradiation dyes, filter light absorbing dyes, anti-bacterial agents, polymer latex, heavy metals, antistatic agents, matting agents Etc. can be contained as required.

  These additives mentioned above are more specifically described in Research Disclosure (hereinafter abbreviated as RD), Volume 176 Item / 17643 (December 1978), Volume 184, Item / 18431 (August 1979), 187. Volume Item / 18716 (November 1979) and Volume 308 Item / 308119 (December 1989).

  The types of compounds and their descriptions shown in these three research disclosures are listed below.

Additive RD17643 RD18716 RD308119
Page Classification Page Classification Page Classification Chemical sensitizer 23 III 648 Upper right 96 III
Sensitizing dye 23 IV 648-649 996-8 IV
Desensitizing dye 23 IV 998 IV
Dye 25-26 VIII 649-650 1003 VIII
Development accelerator 29 XXI 648 Upper right Anti-fogging agent / stabilizer
24 IV 649 Upper right 1006-7 VI
Brightener 24 V 998 V
Hardener 26 X 651 Left 1004-5 X
Surfactant 26-7 XI 650 Right 1005-6 XI
Antistatic agent 27 XII 650 Right 1006-7 XIII
Plasticizer 27 XII 650 Right 1006 XII
Slipper 27 XII
Matting agent 28 XVI 650 Right 1008-9 XVI
Binder 26 XXII 1003-4 IX
Support 28 XVII 1009 XVII
〔electrode〕
In the display element of the present invention, it is preferable that at least one of the counter electrodes is a metal electrode. As the metal electrode, for example, known metal species such as platinum, gold, silver, copper, aluminum, zinc, nickel, titanium, bismuth, and alloys thereof can be used. The metal electrode is preferably a metal having a work function close to the redox potential of silver in the electrolyte. Among them, silver or a silver electrode having a silver content of 80% or more is advantageous for maintaining the reduced state of silver. Excellent in preventing dirt. As an electrode manufacturing method, an existing method such as an evaporation method, a printing method, an ink jet method, a spin coating method, or a CVD method can be used.

  In the display element of the present invention, it is preferable that at least one of the counter electrodes is a transparent electrode. The transparent electrode is not particularly limited as long as it is transparent and conducts electricity. For example, Indium Tin Oxide (ITO: Indium Tin Oxide), Indium Zinc Oxide (IZO: Indium Zinc Oxide), Fluorine Doped Tin Oxide (FTO), Indium Oxide, Zinc Oxide, Platinum, Gold, Silver, Rhodium, Copper, Examples thereof include chromium, carbon, aluminum, silicon, amorphous silicon, and BSO (Bismuth Silicon Oxide). In order to form the electrode in this manner, for example, an ITO film may be vapor-deposited on the substrate by a sputtering method or the like, or an ITO film may be formed on the entire surface and then patterned by a photolithography method. The surface resistance value is preferably 100Ω / □ or less, and more preferably 10Ω / □ or less. The thickness of the transparent electrode is not particularly limited, but is generally 0.1 to 20 μm.

[Other components of the display element]
In the display element of the present invention, a sealant, a columnar structure, and spacer particles can be used as necessary.

  Sealing agent is for sealing so that it does not leak to the outside and is also called sealing agent. Epoxy resin, urethane resin, acrylic resin, vinyl acetate resin, ene-thiol resin, silicon resin, modified resin A curing type such as a polymer resin, such as a thermosetting type, a photocurable type, a moisture curable type, and an anaerobic curable type can be used.

  The columnar structure provides strong self-holding (strength) between the substrates, for example, a columnar body, a quadrangular columnar body, an elliptical columnar body, a trapezoidal array arranged in a predetermined pattern such as a lattice arrangement. A columnar structure such as a columnar body can be given. Alternatively, stripes arranged at predetermined intervals may be used. This columnar structure is not a random array, but can be properly maintained at intervals of the substrate, such as an evenly spaced array, an array in which the interval gradually changes, and an array in which a predetermined arrangement pattern is repeated at a constant period. The arrangement is preferably considered so as not to disturb the display. If the ratio of the area occupied by the columnar structure in the display area of the display element is 1 to 40%, a practically sufficient strength as a display element can be obtained.

  A spacer may be provided between the pair of substrates for uniformly maintaining a gap between the substrates. Examples of the spacer include a sphere made of resin or inorganic oxide. Further, a fixed spacer having a surface coated with a thermoplastic resin is also preferably used. In order to hold the gap between the substrates uniformly, only the columnar structure may be provided, but both the spacer and the columnar structure may be provided, or instead of the columnar structure, only the spacer is used as the space holding member. May be used. The diameter of the spacer is equal to or less than the height of the columnar structure, preferably equal to the height. When the columnar structure is not formed, the diameter of the spacer corresponds to the thickness of the cell gap.

[Display element driving method]
The method for controlling the transparent state and the colored state of the display element of the present invention is preferably determined based on the redox potential of the electrochromic compound and the deposition overvoltage of the metal compound.

  For example, in the case of a display element having an electrochromic compound and a metal compound between counter electrodes, a colored state other than black is shown on the oxidation side and a black state is shown on the reduction side. As an example of the control method in this case, the electrochromic compound is oxidized by applying a voltage higher than the redox potential of the electrochromic compound to show a colored state other than black, and the redox potential of the electrochromic compound and the metal compound By applying a voltage between the deposition overvoltages of the electrochromic compound, the electrochromic compound is reduced and returned to the white state, and by applying a voltage lower than the deposition overvoltage of the metal compound, the metal is deposited on the electrode to show a black state, There is a method of dissolving and decoloring the deposited metal by applying a voltage between the oxidation potential of the metal and the redox potential of the electrochromic compound.

  The driving operation of the display element of the present invention may be simple matrix driving or active matrix driving. The simple matrix driving in the present invention is a driving method in which a current is sequentially applied to a circuit in which a positive line including a plurality of positive electrodes and a negative electrode line including a plurality of negative electrodes are opposed to each other in a vertical direction. Say that. By using simple matrix driving, there is an advantage that the circuit configuration and driving IC can be simplified and manufactured at low cost. The active matrix drive is a system in which scanning lines, data lines, and current supply lines are formed in a grid pattern and are driven by a TFT circuit provided in each grid pattern. Since switching can be performed for each pixel, there are advantages such as gradation and memory function. For example, a circuit described in FIG. 5 of JP-A-2004-29327 can be used.

[Product application]
The display element of the present invention can be used in an electronic book field, an ID card field, a public field, a traffic field, a broadcast field, a payment field, a distribution logistics field, and the like. Specifically, keys for doors, student ID cards, employee ID cards, various membership cards, convenience store cards, department store cards, vending machine cards, gas station cards, subway and railway cards, bus cards, Cash cards, credit cards, highway cards, driver's licenses, hospital examination cards, electronic medical records, health insurance cards, Basic Resident Registers, passports, electronic books, etc.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these.

Example 1
<Production of electrode>
(Production of electrode 1)
An ITO (Indium Tin Oxide) film having a pitch of 145 μm and an electrode width of 130 μm is formed on a glass substrate having a thickness of 1.5 mm and 2 cm × 4 cm according to a known method to obtain a transparent electrode (electrode 1). It was.

(Preparation of electrode 2)
A nickel electrode having an electrode thickness of 0.1 μm, a pitch of 145 μm, and an electrode interval of 130 μm is formed on a glass substrate having a thickness of 1.5 mm and a size of 2 cm × 4 cm by using a known method. And a gold-nickel electrode (electrode 2) having a depth of 0.05 μm replaced with gold from the electrode surface was obtained.

(Preparation of electrode 3)
On the electrode 1, a titanium dioxide film having a thickness of 5 μm (about 4 to 10 particles having an average particle diameter of 17 nm had been necked) was formed to obtain an electrode 3.

(Preparation of electrode 4)
The following ink liquid 1 was applied onto the electrode 3 at 120 dpi using an ink jet apparatus having a piezo-type head to produce the electrode 4. A method for immobilizing a metal salt compound or an electrochromic compound after forming the titanium dioxide layer is referred to as production method 1. In addition, dpi as used in the field of this invention represents the number of dots per 2.54 cm.

(Preparation of electrode 5)
The following ink liquid 2 is applied onto the electrode 3 at 120 dpi in an ink jet apparatus having a piezo-type head, heated at 90 ° C. for 5 minutes to sufficiently evaporate the solvent (electrode 5 ′), and then the following ink The liquid 3 was applied onto the electrode 5 'at 120 dpi using an inkjet apparatus having a piezo-type head, and washed with water for 5 minutes and ethanol for 5 minutes to obtain an electrode 5.

(Preparation of electrode 6)
An electrode 6 was obtained in the same manner except that the ink liquid 2 was changed to the ink liquid 4 in the production of the electrode 5.

(Preparation of electrode 7)
An electrode 7 was obtained in the same manner except that the ink liquid 2 was changed to the ink liquid 4 and the ink liquid 3 was changed to the ink liquid 5 in the production of the electrode 5.

(Preparation of electrode 8)
An electrode 8 was obtained in the same manner as in the production of the electrode 5, except that the ink liquid 2 was changed to the ink liquid 6 and the ink liquid 3 was changed to the ink liquid 5.

(Preparation of electrode 9)
An electrode 9 was obtained in the same manner except that the ink liquid 2 was changed to the ink liquid 7 and the ink liquid 3 was changed to the ink liquid 5 in the production of the electrode 5.

(Production of electrode 10)
An electrode 10 was obtained in the same manner except that the ink liquid 2 was changed to the ink liquid 8 and the ink liquid 3 was changed to the ink liquid 5 in the production of the electrode 5.

(Preparation of electrode 11)
An electrode 11 was obtained in the same manner except that the ink liquid 2 was changed to the ink liquid 9 and the ink liquid 3 was changed to the ink liquid 5 in the production of the electrode 5.

(Preparation of electrode 12)
An electrode 12 was obtained in the same manner as in the production of the electrode 5, except that the ink liquid 2 was changed to the ink liquid 10 and the ink liquid 3 was changed to the ink liquid 5.

(Preparation of electrode 13)
An electrode 13 was obtained in the same manner except that the ink liquid 2 was changed to the ink liquid 11 and the ink liquid 3 was changed to the ink liquid 5 in the production of the electrode 5.

(Preparation of electrode 14)
An electrode 14 was obtained in the same manner as in the production of the electrode 5, except that the ink liquid 2 was changed to the ink liquid 12 and the ink liquid 3 was changed to the ink liquid 5.

(Preparation of electrode 15)
On the electrode 1, the following titanium dioxide solution 1 was applied by a blade method to form a film having a thickness of 5 μm, whereby an electrode 15 was obtained. The production method 2 is a method of forming a titanium dioxide layer using titanium dioxide particles on which a metal salt compound or an electrochromic compound is immobilized in advance.

(Production of electrodes 16 to 25)
In production of the electrode 15, the electrodes 16 to 25 were obtained in the same manner except that the titanium dioxide solution 1 was changed to the following titanium dioxide solutions 2 to 11.

<Preparation of ink liquid>
(Preparation of ink liquid 1)
Compound EC-1 [bis- (2-phosphonoethyl) -4,4′-bipyridinium dibromide] was dissolved in acetonitrile / ethanol so as to be 3 mmol / L to prepare ink liquid 1.

(Preparation of ink liquid 2)
Compound EC-1 [bis- (2-phosphonoethyl) -4,4'-bipyridinium dibromide] was dissolved in acetonitrile / ethanol to 1.5 mmol / L and compound 1-16 to 1.5 mmol / L. Thus, an ink liquid 2 was prepared.

(Preparation of ink liquid 3)
Ink liquid 3 was prepared by dissolving bismuth chloride in water at 3 mmol / L.

(Preparation of ink liquid 4)
Ink liquid 4 was prepared by dissolving Compound A-42 in 1.5 mmol / L and Compound 1-16 in acetonitrile / ethanol so as to be 1.5 mmol / L.

(Preparation of ink liquid 5)
Ink liquid 5 was prepared by dissolving silver nitrate in water to a concentration of 3 mmol / L.

(Preparation of ink liquid 6)
Ink liquid 6 was prepared by dissolving Compound A-42 in 1.5 mmol / L and Compound 1-13 in acetonitrile / ethanol so as to be 1.5 mmol / L.

(Preparation of ink liquid 7)
Ink liquid 7 was prepared by dissolving Compound A-42 in 1.5 mmol / L and Compound 1-11 in acetonitrile / ethanol so as to be 1.5 mmol / L.

(Preparation of ink liquid 8)
Ink liquid 8 was prepared by dissolving compound A-42 in acetonitrile / ethanol so that compound A-42 was 1.5 mmol / L and compound 1-19 was 1.5 mmol / L.

(Preparation of ink liquid 9)
Ink liquid 9 was prepared by dissolving Compound A-113 in acetonitrile / ethanol so that Compound A-113 was 1.5 mmol / L and Compound 1-16 was 1.5 mmol / L.

(Preparation of ink liquid 10)
Ink liquid 10 was prepared by dissolving Compound A-115 in acetonitrile / ethanol so that Compound A-115 was 1.5 mmol / L and Compound 1-16 was 1.5 mmol / L.

(Preparation of ink liquid 11)
Ink liquid 11 was prepared by dissolving compound A-42 in acetonitrile / ethanol so as to be 1.5 mmol / L and compound 1 being 1.5 mmol / L.

(Preparation of ink liquid 12)
Compound A-42 was dissolved in acetonitrile / ethanol so that the compound A-42 was 1.5 mmol / L and compound 2 was 1.5 mmol / L to prepare ink liquid 12.

<Preparation of titanium dioxide solution>
(Titanium dioxide solution 1)
Compound EC-1 [bis- (2-phosphonoethyl) -4,4'-bipyridinium dibromide] was dissolved in acetonitrile / ethanol so as to have a concentration of 3 mmol / L. After addition and stirring, about 17 to 17 particles of 17 nm particles were added, and centrifuged to obtain titanium dioxide particles 1 on which compound EC-1 was immobilized. The obtained titanium dioxide particles 1 were dissolved in N-methylpyrrolidone to prepare a titanium dioxide liquid 1.

(Titanium dioxide solution 2)
Compound EC-1 [bis- (2-phosphonoethyl) -4,4'-bipyridinium dibromide] was dissolved in acetonitrile / ethanol to 1.5 mmol / L and compound 1-16 to 1.5 mmol / L. The titanium dioxide (about 4 to 10 particles having an average particle diameter of 17 nm was necked) was added to the liquid obtained and stirred, and then centrifuged to immobilize Compound EC-1 and Compound 1-16 Titanium particles 2a were obtained. The obtained titanium dioxide particles 2a were added to a 3 mmol / l bismuth chloride aqueous solution, stirred, and then centrifuged to obtain titanium dioxide particles 2b. The obtained titanium dioxide particles 2b were dissolved in N-methylpyrrolidone to prepare a titanium dioxide liquid 2.

(Titanium dioxide solution 3)
A solution obtained by dissolving compound A-42 in acetonitrile / ethanol to 1.5 mmol / l and compound 1-16 to 1.5 mmol / l was added to titanium dioxide (particles having an average particle diameter of 17 nm of 4 to 10). After adding / stirring, the mixture was centrifuged to obtain titanium dioxide particles 3a on which compound A-42 and compound 1-16 were immobilized. The obtained titanium dioxide particles 3a were added to and stirred with a 3 mmol / l bismuth chloride aqueous solution, and then centrifuged to obtain titanium dioxide particles 3b. The obtained titanium dioxide particles 3b were dissolved in N-methylpyrrolidone to prepare a titanium dioxide liquid 3.

(Titanium dioxide solution 4)
A solution obtained by dissolving compound A-42 in acetonitrile / ethanol to 1.5 mmol / l and compound 1-16 to 1.5 mmol / l was added to titanium dioxide (particles having an average particle diameter of 17 nm of 4 to 10). After adding / stirring, the mixture was centrifuged to obtain titanium dioxide particles 4a on which compound A-42 and compound 1-16 were immobilized. The obtained titanium dioxide particles 4a were added to a 3 mmol / l silver nitrate aqueous solution and stirred, and then centrifuged to obtain titanium dioxide particles 4b. The obtained titanium dioxide particles 4b were dissolved in N-methylpyrrolidone to prepare a titanium dioxide liquid 4.

(Titanium dioxide solution 5)
Titanium dioxide solution 5 was prepared in the same manner as in the production of titanium dioxide 4, except that compound 1-16 was changed to compound 1-13.

(Titanium dioxide solution 6)
A titanium dioxide solution 6 was prepared in the same manner as in the production of titanium dioxide 4, except that compound 1-16 was changed to compound 1-11.

(Titanium dioxide solution 7)
A titanium dioxide solution 7 was prepared in the same manner as in the production of titanium dioxide 4, except that compound 1-16 was changed to compound 1-19.

(Titanium dioxide solution 8)
A titanium dioxide solution 8 was prepared in the same manner as in the production of titanium dioxide 4, except that compound A-42 was changed to compound A-113.

(Titanium dioxide solution 9)
A titanium dioxide solution 9 was prepared in the same manner as in the production of titanium dioxide 4, except that compound A-42 was changed to compound A-115.

(Titanium dioxide solution 10)
A titanium dioxide solution 10 was prepared in the same manner as in the production of titanium dioxide 4, except that compound 1-16 was changed to compound 1.

(Titanium dioxide solution 11)
Titanium dioxide liquid 11 was prepared in the same manner as in the production of titanium dioxide 4, except that compound 1-16 was changed to compound 2.

<< Preparation of electrolyte solution >>
(Preparation of electrolyte solution 1)
Electrolyte solution 1 was obtained by dissolving 0.025 g of tetrabutylammonium perchlorate in 2.5 g of dimethyl sulfoxide.

(Preparation of electrolyte solution 2)
In 2.5 g of dimethyl sulfoxide, 0.1 g of bismuth chloride, 0.1 g of lithium bromide, and 0.025 g of tetrabutylammonium perchlorate were dissolved to obtain an electrolyte solution 2.

(Preparation of electrolyte solution 3)
Electrolyte solution 3 was obtained by dissolving 0.025 g of tetrabutylammonium perchlorate in 2.5 g of compound III-4.

<< Production of display element >>
(Preparation of display element 1)
On the periphery of the electrode 2 bordered with an olefin-based sealant containing 10% glass spherical bead spacers with an average particle diameter of 40 μm as a volume fraction, polyvinyl alcohol (average polymerization degree 3500, saponification degree 87% ) Add 20% by mass of titanium dioxide CR-90 made by Ishihara Sangyo Co., Ltd. into an isopropanol solution containing 2% by mass, and apply the mixed liquid dispersed with an ultrasonic disperser so that the film thickness after drying is 20 μm. Then, after drying at 15 ° C. for 30 minutes to evaporate the solvent, it was dried in an atmosphere at 45 ° C. for 1 hour. After sprinkling glass spherical bead spacers having an average particle diameter of 20 μm on the obtained titanium dioxide layer, electrodes 2 and 4 were bonded together and heated and pressed to prepare empty cells. The electrolyte solution 1 was vacuum-injected into the empty cell, and the injection port was sealed with an epoxy-based ultraviolet curable resin to produce a display element 1.

(Preparation of display elements 2 to 26)
In the manufacture of the display element 1, display elements 2 to 26 were obtained in the same manner except that the configuration of the electrolyte solution and the display-side electrode was changed to the configuration described in Table 1.

<< Evaluation of display element >>
About the produced display element, stability of the reflectance when it was repeatedly driven by the following method was evaluated.

(Evaluation of display elements 1 and 2)
Both electrodes of the display element produced were connected to both terminals of a constant voltage power source, and after applying a voltage of +1.5 V for 1 second to erase the color, a voltage of -0.5 V was applied for 1 second for color display. Spectral colorimeter manufactured by Konica Minolta Sensing Co., Ltd. for the reflectance at the maximum absorption wavelength in the visible light region and the reflectance at a wavelength of 550 nm when gray-displayed by applying at -1.5 V for 1 second. Measured with CM-3700d. Under the same driving conditions, driving was performed 10 times in total, and the average values of the obtained coloring state and gray reflectance were calculated separately, and were _designated as R _ave1 and R _ave2 , respectively. Further, after driving repeatedly 10,000 times, R _ave3 and R _ave4 were obtained by the same method. R _COLOR1 = | R _{ave1 −Rave3} | and R _BK1 = | R _{ave2 −Rave4} | were used as an index of stability of reflectance when R _COLOR1 and R _BK1 were repeatedly driven. Here, the smaller the values of R _COLOR1 and R _BK1 , the _better the stability of the reflectance when it is repeatedly driven.

(Evaluation of display elements 3 to 26)
[Evaluation of reflectance stability when driven repeatedly]
Reflectance at the maximum absorption wavelength in the visible light region when both electrodes of the display element are connected to both terminals of the constant voltage power source and a voltage of +1.5 V is applied for 1 second for color display, −1 The reflectance at a wavelength of 550 nm when gray display was applied for 1 second at 5 V was measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing. Under the same driving conditions, driving was performed 10 times in total, and the average values of the obtained coloring state and gray reflectance were calculated separately, and were _designated as R _ave5 and R _ave6 , respectively. Further, after driving repeatedly 10,000 times, R _ave7 and R _ave8 were obtained by the same method. R _COLOR2 = | R _{ave5 −Rave7} | and R _BK2 = | R _{ave6 −Rave8} | were used as indices of stability of reflectance when R _COLOR2 and R _BK2 were repeatedly driven. Here, the smaller the values of R _COLOR2 and R _BK2 , the _better the stability of the reflectance when repeatedly driven.

  The evaluation results are shown in Table 1.

  As is clear from the results shown in Table 1, it can be seen that the display element of the present invention has improved reflectance stability when it is repeatedly driven as compared with the comparative example.

Claims (8)

The counter electrode has an electrolyte, and at least one of the counter electrodes has a porous layer made of a metal oxide, and both the metal salt compound and the electrochromic compound are immobilized on the porous layer. A display element that performs black display, white display, and color display other than black by driving the counter electrode. 2. The porous layer is composed of metal oxide particles, and the metal oxide particles are metal oxide particles in which a metal salt compound and an electrochromic compound are immobilized in advance. Display element. The display element according to claim 1, wherein the metal salt compound is a silver salt compound. The display element according to claim 1, wherein the electrochromic compound is a compound represented by the following general formula (A).

[Wherein, R ¹ represents a substituted or unsubstituted aryl group, and R ² and R ³ each represent a hydrogen atom or a substituent. X represents> N—R ⁴ , an oxygen atom or a sulfur atom, and R ⁴ represents a hydrogen atom or a substituent. ] The display element according to claim 1, wherein the metal salt compound is a salt of a compound represented by the following general formula (1) and a metal.
Formula (1) R ₁ -L-SM
[Wherein R ₁ represents —COOH, —P═O (OH) ₂ , —OP═O (OH) ₂ or —Si (OR) ₃ (R represents an alkyl group), and L represents Represents a linking group, and M represents a hydrogen atom, a metal atom or quaternary ammonium. ] The display element according to claim 5, wherein a metal salt compound is formed after the compound represented by the general formula (1) is immobilized on the porous layer. The compound represented by the general formula (A) is —COOH, —P═O (OH) ₂ , —OP═O (OH) ₂ or —Si (OR) ₃ (R represents an alkyl group.) In a molecule | numerator, The display element of any one of Claims 1-6 characterized by the above-mentioned. The display element according to claim 1, wherein the electrolyte contains a compound represented by the following general formula (III) or (IV).

[Wherein, L represents an oxygen atom or CH ₂ , and R ^{8 to} R ¹¹ each represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group, or an alkoxy group. ]

[Wherein, R ¹² and R ¹³ each represent a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group or an alkoxy group. ]