JP2010085572A - Electrochemical display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrochemical display element which has a simple member configuration and can be driven with a low voltage and is superior in drive stability. <P>SOLUTION: The electrochemical display element includes an electrolyte layer containing a metal salt compound and at least one of compounds represented by general formula (G-2) between electrodes facing each other, wherein one electrode on a display viewable side out of the electrodes facing each other is modified by a silane coupling agent and an auxiliary compound which can be oxidized and reduced is fixed to the other electrode on the side opposite to the one electrode on the display viewable side, and the electrochemical display element displays black and white by application of a voltage between the electrodes facing each other. In the general formula, Z represents an atom group necessary for forming a nitrogen containing heterocycle, n represents an integer of 0 to 5, and Rg<SB>21</SB>represents a substitution group, and if n≥2, respective Rg<SB>21</SB>may be of the same, may be different, and may couple to each other to form a condensed ring. <P>COPYRIGHT: (C)2010,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, information such as documents and images provided on printed paper on paper has become easier to use electronic information. Opportunities to obtain and browse electronic information are increasing more and more.

  As a means for browsing such electronic information, a conventional liquid crystal display or CRT, and in recent years, a light emitting type such as an organic EL display is mainly used. In particular, when the electronic information is document information, it is relatively long time. It is necessary to pay close attention to this browsing means, and these actions are not necessarily human-friendly means. Generally, as a drawback of light-emitting displays, eyes flicker due to flickering, inconvenient to carry, reading posture is limited It is known that it is necessary to adjust the line of sight to a still screen, and that power consumption increases when read for a long time.

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

  That is, the method using a polarizing plate such as a reflective liquid crystal has a low reflectance of about 40%, which makes it difficult to display white, and it is difficult to say that many of the manufacturing methods used to manufacture the constituent members are simple. 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 display method for eliminating the drawbacks of each of the above-described methods, an electrodeposition method (hereinafter, abbreviated as ED method) using dissolution precipitation of metal or metal salt is known. The ED method can be driven at a low voltage of 3 V or less, has advantages such as a simple cell configuration, excellent black-white contrast and black quality, and various methods have been disclosed (for example, Patent Document 1). -3)).

As a result of examining the techniques disclosed in each of the above patent documents in detail, the present inventor has found that there is a problem in the stability of the reflectance when it is repeatedly driven, and solves this problem. As a means, there is a technique in which the surface of the display side electrode is modified with a palladium thin film to improve the durability of the display side electrode (Patent Document 4). This technology is a technology that improves the driving stability as a result of the improvement of the durability of the display side electrode. However, regarding the driving stability deterioration due to the characteristic variation of the electrolyte and the characteristic variation of the electrode facing the display side electrode, , Found to have little or no effect.
U.S. Pat. No. 4,240,716 Japanese Patent No. 3428603 JP 2003-241227 A JP-A-11-142895

  The present invention has been made in view of the above problems, and an object thereof is to provide a display element that has a simple member configuration, can be driven at a low voltage, and has excellent driving stability.

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

  1. Between the counter electrodes, there is an electrolyte layer containing at least one of a metal salt compound and a compound represented by the following general formula (G-2), and the electrode on the side where the display can be seen is a silane cup An auxiliary compound that is modified with a ring agent and that can be oxidized / reduced is fixed to an electrode on the side opposite to the electrode on which the display can be seen, and black is applied by applying a voltage between the counter electrodes. An electrochemical display element characterized by displaying white.

[Wherein Z represents an atomic group necessary for constituting a nitrogen-containing heterocyclic ring. n represents an integer of 0 to 5, Rg ₂₁ represents a substituent, and when n is 2 or more, each Rg ₂₁ may be the same or different, and may be connected to each other to form a condensed ring. It may be formed. ]
2. When the molar concentration of metal ions in the metal salt compound is [Metal] (mol / kg) and the total molar concentration of halogen ions or halogen atoms of halogen molecules is [x] (mol / kg), 0 <[ 2. The electrochemical display device as described in 1 above, wherein the condition x] / [Metal] ≦ 0.01 is satisfied.

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

  4). 4. The electrochemical display element according to any one of 1 to 3, wherein the silane coupling agent has a —SH group.

  5. 5. The electrochemical display element according to any one of 1 to 4, wherein the auxiliary compound is a ferrocene derivative.

  6). 5. The electrochemical display element according to any one of 1 to 4, wherein the auxiliary compound is an N oxyl derivative.

  7). The electrochemical display element according to any one of 1 to 6 above, wherein the electrolyte layer contains at least one selected from compounds represented by the following general formulas (S1) and (S2): .

[Wherein L represents an oxygen atom or an alkylene group, and Rs ₁₁ to Rs ₁₄ 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 Rs ₂₁ and Rs ₂₂ each represents 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 an electrochemical display element that has a simple member configuration, can be driven at a low voltage, and has excellent driving stability.

  The electrochemical display element of the present invention has an electrolyte layer containing at least one of a metal salt compound and the compound represented by the general formula (G-2) between the counter electrodes, and among the counter electrodes The display-side electrode is modified with a silane coupling agent, and an auxiliary compound that can be oxidized and reduced is immobilized on the electrode on the side opposite to the display-side electrode. An electrochemical display element excellent in stability could be provided.

  Details of the present invention will be described below.

[Basic structure of display element]
In the electrochemical display element of the present invention (also simply referred to as a display element), one corresponding counter electrode is provided in the display portion. A transparent electrode such as an ITO electrode modified with a silane coupling agent is fixed to the electrode 1 (display side electrode) which is one of the counter electrodes close to the display portion, and an auxiliary compound capable of oxidation / reduction is fixed to the other electrode 2 Conductive electrodes are provided. Between the electrode 1 and the electrode 2, an electrolyte containing the metal salt compound according to the present invention and the compound represented by the general formula (G-2) is provided, and a positive and negative voltage is applied between the counter electrodes. By doing so, it is possible to reversibly switch between white display and black display.

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

[Halogen ion, metal ion concentration ratio]
In the display element of the present invention, the molar concentration of halogen ions or halogen atoms contained in the electrolyte is [X] (mol / kg), and silver contained in the electrolyte or the total silver of the compound containing silver in the chemical structure. When the molar concentration is [Metal] (mol / kg), it is preferable to satisfy the condition defined by the following formula (1).

Formula (1): 0 ≦ [X] / [Metal] ≦ 0.1
The halogen atom as used in the field of this invention means an iodine atom, a chlorine atom, a bromine atom, and a fluorine atom. When [X] / [Metal] is larger than 0.1, X− → X ₂ is generated during the oxidation-reduction reaction of the metal, and X ₂ easily cross-oxidizes with the deposited metal to dissolve the deposited metal. Therefore, the molar concentration of halogen atoms is preferably as low as possible relative to the molar concentration of metallic silver. In the present invention, 0 ≦ [X] / [Metal] ≦ 0.001 is more preferable. In the case of adding halogen ions, the halogen species preferably have a total molar concentration of [I] <[Br] <[Cl] <[F] from the viewpoint of improving memory properties.
[Compound represented by General Formula (G-2)]
The compound represented by the general formula (G2) according to the present invention will be described.

In the general formula (G2), Z represents a nitrogen-containing heterocyclic ring excluding imidazole rings. n represents an integer of 0 to 5, Rg ₂₁ represents a substituent, and when n is 2 or more, each Rg ₂₁ may be the same or different, and may be connected to each other to form a condensed ring. It may be formed.

  Examples of the nitrogen-containing heterocycle having Z as a constituent in general formula (G2) include, for example, 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 benzimidazole Ring, benzothiazole ring, benzoselenazole ring, naphthoxazole ring and the like.

The substituents represented by Rg ₂₁ of the general formula (G2), not particularly limited, but include for example substituents such as the following.

  A halogen atom (eg, fluorine atom, chlorine atom, bromine atom, iodine atom), an alkyl group (eg, methyl, ethyl, propyl, i-propyl, butyl, t-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, Dodecyl, hydroxyethyl, methoxyethyl, trifluoromethyl, benzyl, etc.), aryl groups (eg, phenyl, naphthyl, etc.), alkylcarbonamide groups (eg, acetylamino, propionylamino, butyroylamino, etc.), arylcarbonamide groups (For example, benzoylamino, etc.), alkylsulfonamide groups (for example, methanesulfonylamino group, ethanesulfonylamino group, etc.), arylsulfonamide groups (for example, benzenesulfonylamino group, toluenesulfonylamino group, etc.), Lucoxy group, aryloxy group (for example, phenoxy), alkylthio group (for example, methylthio, ethylthio, butylthio, etc.), arylthio group (for example, phenylthio group, tolylthio group, etc.), alkylcarbamoyl group (for example, methylcarbamoyl, dimethylcarbamoyl, Ethylcarbamoyl, diethylcarbamoyl, dibutylcarbamoyl, piperidylcarbamoyl, morpholylcarbamoyl, etc.), arylcarbamoyl groups (eg, phenylcarbamoyl, methylphenylcarbamoyl, ethylphenylcarbamoyl, benzylphenylcarbamoyl, etc.), carbamoyl groups, alkylsulfamoyl groups ( For example, methylsulfamoyl, dimethylsulfamoyl, ethylsulfamoyl, diethylsulfamoyl, dibutylsulfamo Moyl, piperidylsulfamoyl, morpholylsulfamoyl, etc.), arylsulfamoyl groups (eg, phenylsulfamoyl, methylphenylsulfamoyl, ethylphenylsulfamoyl, benzylphenylsulfamoyl, etc.), sulfamoyl groups , Cyano group, alkylsulfonyl group (for example, methanesulfonyl group, ethanesulfonyl group, etc.), arylsulfonyl group (for example, phenylsulfonyl, 4-chlorophenylsulfonyl, p-toluenesulfonyl, etc.), alkoxycarbonyl group (for example, methoxycarbonyl, Ethoxycarbonyl, butoxycarbonyl etc.), aryloxycarbonyl group (eg phenoxycarbonyl etc.), alkylcarbonyl group (eg acetyl, propionyl, butyroyl etc.), arylcal Bonyl group (for example, benzoyl group, alkylbenzoyl group, etc.), acyloxy group (for example, acetyloxy, propionyloxy, butyroyloxy, etc.), carboxyl group, carbonyl group, sulfonyl group, amino group, hydroxy group or heterocyclic group (for example, Oxazole ring, thiazole ring, triazole ring, selenazole ring, tetrazole ring, oxadiazole ring, thiadiazole ring, thiazine ring, triazine ring, benzoxazole ring, benzthiazole ring, indolenine ring, benzselenazole ring, naphthothiazole ring, Triazaindolizine ring, diazaindolizine ring, tetraazaindolizine ring group, etc.). These substituents further include those having a substituent.

  Next, although the preferable specific example of a compound represented by general formula (G2) is shown, this invention is not limited to these compounds.

  Of the above-exemplified compounds, Exemplified Compounds G2-12 and G2-20 are particularly preferable from the viewpoint that the object and effects of the present invention can be exhibited.

〔Silane coupling agent〕
In the present invention, the kind of the silane coupling agent to be processed for the display side electrode is not particularly limited, and a silane coupling agent blended in rubber or plastic can be used conventionally. For example, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ -Glycidoxypropyltrimethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ- Methacryloxypropyltriethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-amino Propyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, bis Examples include-(3- [triethoxysilyl] -propyl) -tetrasulfane and n-octadecyltriethoxysilane. Among these, a silane coupling agent having an SH group such as γ-mercaptopropyltrimethoxysilane is preferable.

[Auxiliary compounds that can be redox]
In the display device of the present invention, in order to promote the oxidation-reduction reaction of the metal salt compound, an auxiliary compound that can be oxidized and reduced (hereinafter referred to as a promoter) is used by being immobilized on a porous electrode. To do. The promoter may be one that does not change the optical density in the visible region (400 to 700 nm) or may change as a result of the oxidation-reduction reaction.

  For example, when color is generated by reduction (or oxidation) of a metal oxide on the display electrode side, a high color density can be obtained with a low driving voltage by using an oxidation (or reduction) reaction of a promoter on the counter electrode side. It becomes. Thus, when a promoter is used as a counter electrode reactant, it is preferable to use a promoter having a redox activity opposite to that of the metal oxide, immobilized on the counter electrode. When a promoter is used as a counter electrode material, it is preferable that the promoter does not change the optical density in the visible region (400 to 700 nm) as a result of the redox reaction. However, as described in the preferred embodiment of the present invention, the optical density in the visible region (400 to 700 nm) changes in the case of using a white scatterer in the display element to shield the color development by the promoter. A promoter may be used. Such a configuration is preferable because it facilitates selection of a promoter.

Examples of preferred promoters that can be used in the present invention include the following compounds.
1) Compounds having an N—O bond, such as N-oxyl derivatives such as TEMPO, N-hydroxyphthalimide derivatives, and hydroxamic acid derivatives.
2) A compound having an allyloxy free radical having a bulky substituent introduced at the 0-position, such as galvinoxyl.
3) Metallocene derivatives such as ferrocene.
4) A benzyl (diphenylethanedione) derivative.
5) Tetrazolium salt / formazan derivative.
6) Azine compounds such as phenazine, phenothiazine, phenoxazine, and acridine.
7) Pyridinium compounds such as viologen.

  In addition, hydrazyl free radical compounds such as benzoquinone derivatives, verdazil, thiazyl free radical compounds, hydrazone derivatives, phenylenediamine derivatives, triallylamine derivatives, tetrathiafulvalene derivatives, tetracyanoquinodimethane derivatives, thianthrene derivatives, etc. can also be used as promoters. .

  In the display element of the present invention, promoters in the categories 1) to 7) are preferable, and 1) is particularly preferable.

  Hereinafter, compounds in the category 1) will be described in detail.

  N-oxyl (also called nitroxide radical) is an oxygen-centered radical generated by radically cleaving the oxygen-hydrogen bond of hydroxylamine. The nitroxide radical is known to have two reversible redox pairs as shown in the following scheme. The nitroxide radical becomes an oxoammonium cation by one-electron oxidation, which is reduced to regenerate the radical. The nitroxide radical is converted into an aminoxy anion by one-electron reduction, which is oxidized to regenerate the radical. Therefore, the nitroxide radical can function as a p-type counter electrode reactant or an n-type counter electrode reactant.

  The N-oxyl derivative is immobilized on the electrode surface by introducing a group that chemically or physically adsorbs with the electrode surface into the N-oxyl derivative or by polymerizing the N-oxyl derivative to form a thin film on the electrode surface. The method of doing is mentioned. The N-oxyl derivative may be added in the form of an N-oxyl radical, or may be added in the form of an N-hydroxy compound, and further in the form of an oxoammonium cation.

  As N-oxyl derivatives, derivatives substituted with various substituents such as TEMPO (2,2,6,6-tetramethylpiperidinyl-N-oxyl) are commercially available. In addition, various derivatives including polymers can be easily synthesized according to known literature.

  In general, when hydrogen is substituted on the α-position carbon of the nitroxide radical, it is known that it easily disproportionates to hydroxyamine and nitrone. For this reason, the four methyl groups at the N-oxyl group α-position of TEMPO can be said to be indispensable structures for existing as stable radicals, but conversely, the reactivity may decrease due to steric hindrance of these four methyl groups. is there. Azaadamantane N-oxyl derivatives or azabicyclo N-oxyl derivatives are preferred in that they do not cause a decrease in activity.

  Next, N-hydroxyphthalimide derivatives, hydroxamic acid derivatives and the like will be described. As shown in the following scheme, phthalimide N-oxyl (PINO) generated by electrode oxidation of N-hydroxyphthalimide (NHPI) oxidizes a secondary alcohol to produce a ketone. As can be seen from this example, it is understood that the redox couple of NHPI / PINO functions as a counter electrode reactant or mediator even in the display element of the present invention. As with NHPI, hydroxamic acid derivatives and trihydroxyimino cyanuric acid (THICA) can also be used as promoters.

  When the display element of the present invention is produced using these compounds, it is preferably added in the state of N—OH. After producing a display element in the state of N—OH, radicals are generated by driving the display element to oxidize.

  The promoter represented by the category of 1) can be represented by the following general formula (M1), and promoters represented by the following general formulas (M2) to (M5) are preferable. In particular, a polycyclic N-oxyl derivative represented by the general formula (M6) is preferable.

  Various promoters represented by the general formulas (M1) to (M5) are commercially available and can be easily obtained. In addition, various derivatives can be easily synthesized according to known literature. The promoter represented by the general formula (M6) is J.P. Am. Chem. Soc. , 128, 8412 (2006) and Tetrahedron Letters 49 (2008) 48-52.

  Further, promoters obtained by polymerizing these are, for example, JP-A Nos. 2004-227946, 2004-228008, 2006-73240, 2007-35375, 2007-70384, and 2007-184227. Can be synthesized with reference to Japanese Patent Publication No. 2007-298713.

In the formula, Rm ₁₁ and Rm ₁₂ are each independently an optionally substituted aliphatic hydrocarbon group, aromatic hydrocarbon group, heterocyclic group, or>C═O,>C═S,> C═N. A group bonded to a nitrogen atom via —Rm ₁₃ ; Rm ₁₃ represents a hydrogen atom or an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic group which may have a substituent. Rm ₁₁ and Rm ₁₂ may be connected to each other to form a cyclic structure. ]
In the general formula (M1), Rm ₁₁ and Rm ₁₂ are each independently an optionally substituted aliphatic hydrocarbon group, aromatic hydrocarbon group, heterocyclic group, or>C═O,> C═S. ,> C═N—Rm represents a group bonded to a nitrogen atom via ₁₃ . Rm13 represents a hydrogen atom, an aliphatic hydrocarbon group which may have a substituent, an aromatic hydrocarbon group or a heterocyclic group. Rm ₁₁ and Rm ₁₂ may be connected to each other to form a cyclic structure.

  The aliphatic hydrocarbon group includes chain and cyclic groups, and the chain group includes linear and branched groups. Such aliphatic hydrocarbon groups include methyl, ethyl, vinyl, propyl, isopropyl, propenyl, butyl, iso-butyl, tert-butyl, pentyl, isopentyl, neopentyl, hexyl, iso-hexyl, cyclohexyl, cyclohexenyl, Examples include octyl, iso-octyl, cyclooctyl, 2,3-dimethyl-2-butyl and the like.

  Examples of the aromatic hydrocarbon group include a phenyl group and a naphthyl group. Examples of the heterocyclic group include a pyridyl group, a thiazolyl group, an oxazolyl group, an imidazolyl group, a furyl group, a pyrrolyl group, a pyrazinyl group, a pyrimidinyl group, and a pyridazinyl group. , Serenazolyl group, sulfolanyl group, piperidinyl group, pyrazolyl group, tetrazolyl group, morpholino group and the like.

  These substituents may further have a substituent. These substituents are not particularly limited, and examples thereof include alkyl groups (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, Tetradecyl group, pentadecyl group etc.), cycloalkyl group (eg cyclopropyl group, cyclopentyl group, cyclohexyl group etc.), alkenyl group (eg vinyl group, allyl group, butenyl group, octenyl group etc.), cycloalkenyl group (eg , 2-cyclopenten-1-yl group, 2-cyclohexen-1-yl group, etc.), alkynyl group (eg, propargyl group, ethynyl group, trimethylsilylethynyl group, etc.), aryl group (eg, phenyl group, naphthyl group, p) -Tolyl group, m-chlorophenyl group, o-hexadecanoylamino Phenyl group, etc.), heterocyclic group (for example, pyridyl group, thiazolyl group, oxazolyl group, imidazolyl group, furyl group, pyrrolyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, selenazolyl group, sulfolanyl group, piperidinyl group, pyrazolyl group, Tetrazolyl group, morpholino group, etc.), heterocyclic oxy group (for example, 1-phenyltetrazol-5-oxy group, 2-tetrahydropyranyloxy group, pyridyloxy group, thiazolyloxy group, oxazolyloxy group, imidazolyloxy group, etc.) ), Halogen atoms (for example, chlorine atom, bromine atom, iodine atom, fluorine atom, etc.), alkoxy groups (for example, methoxy group, ethoxy group, propyloxy group, tert-butoxy group, pentyloxy group, hexyloxy group, octyl) Oxy group, dodecyloxy Group), cycloalkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (for example, phenoxy group, 2-naphthyloxy group, 2-methylphenoxy group, 4-tert-butylphenoxy group, 3 -Nitrophenoxy group, 2-tetradecanoylaminophenoxy group, etc.), alkylthio group (for example, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), cycloalkylthio group (for example, Cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (for example, phenylthio group, 1-naphthylthio group, etc.), heterocyclic thio group (for example, pyridylthio group, thiazolylthio group, oxazolylthio group, imidazolylthio group, furylthio group, pinyl) Rorylthio group, etc.), alkoxycarbonyl group (eg, methoxycarbonyl group, ethoxycarbonyl group, butoxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl) Group), sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylamino) Sulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, morpholinosulfonyl group, pyrrolidinosulfonyl group, etc.), ureido (For example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group, etc.), acyl group (for example, acetyl group Ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (for example, Formyloxy, acetyloxy, pivaloyloxy, stearoyloxy, benzoyloxy, p-methoxyphenylcarbonyloxy, ethylcarbonyloxy, Rucarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), acylamino group (for example, acetylamino group, benzoylamino group, formylamino group, pivaloylamino group, lauroylamino group, 3, 4, 5-tri-n-octyloxyphenylcarbonylamino group), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octyl) Aminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group , Morpholinocarbonyl group, piperazinocarbonyl group, etc.), alkanesulfinyl group or arylsulfinyl group (for example, methanesulfinyl group, ethanesulfinyl group, butanesulfinyl group, cyclohexanesulfinyl group, 2-ethylhexanesulfinyl group, dodecanesulfinyl group) , Phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkanesulfonyl group or arylsulfonyl group (for example, methanesulfonyl group, ethanesulfonyl group, butanesulfonyl group, cyclohexanesulfonyl group, 2-ethylhexanesulfonyl group, Dodecanesulfonyl group, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (for example, amino group, methylamino group, Tilamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, N-methylanilino group, diphenylamino group, naphthylamino group, 2-pyridylamino group), silyloxy group (Eg, trimethylsilyloxy group, tert-butyldimethylsilyloxy group, etc.), aminocarbonyloxy group (eg, N, N-dimethylcarbamoyloxy group, N, N-diethylcarbamoyloxy group, morpholinocarbonyloxy group, N, N -Di-n-octylaminocarbonyloxy group, Nn-octylcarbamoyloxy group, etc.), alkoxycarbonyloxy group (for example, methoxycarbonyloxy group, ethoxycarbonyloxy group, tert-butoxycarbonyl) Oxy group, n-octylcarbonyloxy group, etc.), aryloxycarbonyloxy group (for example, phenoxycarbonyloxy group, p-methoxyphenoxycarbonyloxy group, pn-hexadecyloxyphenoxycarbonyloxy group, etc.), alkoxycarbonylamino Groups (for example, methoxycarbonylamino group, ethoxycarbonylamino group, tert-butoxycarbonylamino group, n-octadecyloxycarbonylamino group, N-methyl-methoxycarbonylamino group, etc.), aryloxycarbonylamino groups (for example, phenoxycarbonyl) Amino group, p-chlorophenoxycarbonylamino group, mn-octyloxyphenoxycarbonylamino group, etc.), sulfamoylamino group (for example, sulfamoylamino group, N, N -Dimethylaminosulfonylamino group, Nn-octylaminosulfonylamino group, etc.), mercapto group, arylazo group (eg, phenylazo group, naphthylazo group, p-chlorophenylazo group, etc.), heterocyclic azo group (eg, pyridylazo group) , Thiazolylazo group, oxazolylazo group, imidazolylazo group, furylazo group, pyrrolylazo group, 5-ethylthio-1,3,4-thiadiazol-2-ylazo group, etc., imino group (for example, N-succinimido-1-yl group, N-phthalimido-1-yl group, etc.), phosphino group (for example, dimethylphosphino group, diphenylphosphino group, methylphenoxyphosphino group, etc.), phosphinyl group (for example, phosphinyl group, dioctyloxyphosphinyl group, di) Ethoxyphosphinyl group, etc.), phosphine Nyloxy group (for example, diphenoxyphosphinyloxy group, dioctyloxyphosphinyloxy group, etc.), phosphinylamino group (for example, dimethoxyphosphinylamino group, dimethylaminophosphinylamino group, etc.), silyl group (For example, trimethylsilyl group, tert-butyldimethylsilyl group, phenyldimethylsilyl group, etc.), cyano group, nitro group, hydroxyl group, sulfo group, carboxyl group and the like can be mentioned.

  The compound represented by the general formula (M1) may be a multimer such as a dimer or trimer linked by these substituents, or may be a polymer.

In the formula, Rm ₂₁ , Rm ₂₂ , Rm ₂₃ , and Rm ₂₄ each independently represent an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic group that may have a hydrogen atom or a substituent. The atoms constituting Rm ₂₁ to Rm ₂₄ and Z1 may be connected to each other to form a cyclic structure, and Z ₁ may further have a substituent.

In the general formula (M2), Rm ₂₁ , Rm ₂₂ , Rm ₂₃ and Rm ₂₄ are each independently an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic group which may have a hydrogen atom or a substituent. Represents. These aliphatic hydrocarbon group, aromatic hydrocarbon group, and heterocyclic group have the same meanings as those in formula (M1).

Z ₁ represents an atomic group necessary for forming a cyclic structure, and preferably forms a 5-membered ring or a 6-membered ring. Z ₁ may further have a substituent, and examples of the substituent include the same substituents as exemplified in the general formula (M1). The atoms constituting Rm _{21 to} Rm ₂₄ and Z ₁ may be linked to each other to form a cyclic structure. For example, together with the nitrogen atom, a polycyclic structure such as an azanorbornene structure or an azaadamantane structure is taken. Also good.

  The ring structure of the compound represented by the general formula (M2) is preferably a piperidine ring, a pyrrolidine ring, or an azaadamantane ring.

In the formula, Rm ₃₁ is an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic group which may have a substituent, which is substituted directly or through an oxygen atom, a nitrogen atom, or a sulfur atom with a carbonyl carbon atom. Rm ₃₂ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic group which may have a substituent. Rm ₃₁ and Rm ₃₂ may be connected to each other to form a ring structure.

  In the present invention, it is one of the preferred embodiments that the N-oxyl derivative according to the present invention is a compound represented by the general formula (M3).

In the general formula (M3), Rm ₃₁ may be substituted with a carbonyl carbon atom directly or through an oxygen atom, a nitrogen atom, or a sulfur atom, and may have an aliphatic hydrocarbon group or aromatic hydrocarbon which may have a substituent. Rm ₃₂ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic group which may have a substituent. These aliphatic hydrocarbon group, aromatic hydrocarbon group, and heterocyclic group have the same meanings as those in formula (M1). Rm ₃₁ and Rm ₃₂ may be connected to each other to form a cyclic structure. In the general formula (M3), Rm ₃₂ is preferably an aromatic hydrocarbon group, particularly preferably a phenyl group which may have a substituent. The substituent on the phenyl group is preferably an electron-withdrawing group such as a cyano group, an alkoxycarbonyl group, or a trifluoromethyl group. Rm ₃₁ is preferably a phenyl group or an aliphatic hydrocarbon group directly bonded to a carbonyl carbon atom, particularly preferably a branched alkyl group or a cycloalkyl group.

  In addition, it is preferable to add the compound represented by general formula (M3) in the state of N-OH to produce a display element.

In the formula, Z ₂ represents an atomic group necessary for forming a cyclic structure, and may further have a substituent.

  In this invention, it is one of the preferable aspects that the N-oxyl derivative which concerns on this invention is a compound represented by the said general formula (M4).

In the general formula (M4), Z ₂ represents an atomic group necessary for forming a cyclic structure, and preferably forms a 5-membered ring or a 6-membered ring. Z ₂ may further have a substituent, and examples of the substituent include the substituents exemplified in Formula (M1). Z ₂ may be a condensed ring.

  Note that the compound represented by the general formula (M4) is preferably added in the state of N—OH to produce a display element.

In the formula, Rm ₅₁ to Rm ₅₅ each independently represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic group which may have a substituent.

  In this invention, it is one of the preferable aspects that the N-oxyl derivative which concerns on this invention is a compound represented by the said general formula (M5).

In the general formula (M5), Rm ₅₁ to Rm ₅₅ each independently represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic group which may have a substituent. These aliphatic hydrocarbon group, aromatic hydrocarbon group, and heterocyclic group have the same meanings as those in formula (M1).

In the general formula (M5), Rm ₅₁ is preferably an aromatic hydrocarbon group, particularly preferably a phenyl group which may have a substituent. The substituent on the phenyl group is preferably an electron-withdrawing group such as a cyano group, an alkoxycarbonyl group, or a trifluoromethyl group. As Rm ₅₂ to Rm ₅₅ , an alkyl group having 1 to 6 carbon atoms is preferable, and a methyl group is particularly preferable.

In the formula, Rm ₆₁ and Rm ₆₂ each independently represent a hydrogen atom or an aliphatic hydrocarbon group which may have a substituent, and Z ₃ , Z ₄ and Z ₅ are atomic groups necessary for forming a cyclic structure. N represents 0 or 1.

In the general formula (M6), Rm ₆₁ and Rm ₆₂ each independently represent a hydrogen atom or an aliphatic hydrocarbon group which may have a substituent. Rm ₆₁ and Rm ₆₂ are preferably a hydrogen atom or a linear alkyl group having 4 or less carbon atoms, and at least one of Rm ₆₁ and Rm ₆₂ is preferably a hydrogen atom.

Z ₃ , Z ₄ and Z ₅ each represent an atomic group necessary for forming a cyclic structure (for example, carbon, nitrogen, oxygen, sulfur, etc.), and each preferably forms a 5-membered ring or a 6-membered ring. Z ₃ , Z ₄ and Z ₅ may further have a substituent.

  n represents 0 or 1, but when n = 0, the general formula (6) represents a bicyclo compound, and when n = 1, a tricyclo compound.

  As the compound represented by the general formula (M6), n = 1 is preferable, and an azaadamantane derivative is particularly preferable.

  Specific examples of promoters that can be used in the present invention are shown below, but are not limited thereto.

[Electrolyte solvent]
Solvents are generally used in electrochemical cells and batteries, and dissolve various additives such as electrochromic compounds used in the present invention, metal salt compounds that are reversibly dissolved and precipitated by electrochemical redox reactions, and promoters. Any solvent can be used.

  Specifically, acetic anhydride, methanol, ethanol, tetrahydrofuran, ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, butylene carbonate, propylene carbonate, nitromethane, acetonitrile, acetylacetone, N-methylformamide, N, N-dimethylformamide , Dimethyl sulfoxide, hexamethylphosphoamide, dimethoxyethane, diethoxyfuran, γ-butyrolactone, γ-valerolactone, sulfolane, propionitrile, butyronitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, N-methylacetamide, N, N -Dimethylacetamide, N-methylpropionamide, methylpyrrolidinone, 2- (N-methyl) -2-pyrrolidi Non, dimethyl sulfoxide, dioxolane, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, ethyl dimethyl phosphate, tributyl phosphate, tripentyl phosphate, trihexyl phosphate, triheptyl phosphate, trioctyl phosphate, trinonyl phosphate, tridecyl phosphate, tris (Trifluoromethyl) phosphate, tris (pentafluoroethyl) phosphate, triphenyl phosphate, tricresyl phosphate, 2-ethylhexyl phosphate, tetramethylurea, 1,3-dimethyl-2-imidazolidinone, hexamethylphosphotriamide 4-methyl-2-pentanone, dioctyl phthalate, dioctyl sebacate, and ethylene glycol Lumpur, diethylene glycol, polyethylene glycols such as triethylene glycol monobutyl ether and the like can be used.

  Furthermore, room temperature molten salts can also be used as solvents. The room temperature molten salt is a salt composed of ion pairs that are melted at room temperature (that is, in a liquid state) consisting only of ion pairs that do not contain a solvent component, and usually has a melting point of 20 ° C. or lower, A salt consisting of an ion pair that is liquid at a temperature above. The room temperature molten salt can be used alone or in combination of two or more.

  The electrolyte solvent used in the present invention is preferably an aprotic polar solvent, particularly propylene carbonate, ethylene carbonate, dimethyl sulfoxide, dimethoxyethane, acetonitrile, γ-butyrolactone, sulfolane, dioxolane, dimethylformamide, dimethoxyethane, tetrahydrofuran, adiponitrile, Methoxyacetonitrile, dimethylacetamide, methylpyrrolidinone, dimethyl sulfoxide, dioxolane, sulfolane, trimethyl phosphate and triethyl phosphate are preferred. The solvent may be used alone or in combination of two or more.

In the present invention, a particularly preferably used solvent is a compound represented by the general formula (S1) or (S2).
[Compounds Represented by General Formulas (S1) and (S2)]
In the general formula (S1), L represents an oxygen atom or an alkylene group, and Rs ₁₁ to Rs ₁₄ each represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group, or an alkoxy group.

In the general formula (S2), Rs ₂₁ and Rs ₂₂ each represents an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group, or an alkoxy group.

  First, the detail of the compound represented by general formula (S1) is demonstrated.

In the general formula (S1), L represents an oxygen atom or CH ₂ , and Rs ₁₁ to Rs ₁₄ each represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group, or an alkoxy group, These substituents may be further substituted with an arbitrary substituent.

  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.

  Hereinafter, although the specific example of a compound represented by general formula (S1) is shown, in this invention, it is not limited only to these illustrated compounds.

  Next, details of the compound represented by formula (S2) according to the present invention will be described.

In the general formula (S2), Rs ₂₁ and Rs ₂₂ 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.

  Hereinafter, although the specific example of a compound represented by general formula (S2) is shown, in this invention, it is not limited only to these illustrated compounds.

  Of the compounds represented by the general formulas (S1) and (S2) exemplified above, the exemplary compounds (S1-1), (S1-2), and (S2-3) are particularly preferable.

  The compounds represented by the general formulas (S1) and (S2) according to the present invention are one type of electrolyte solvent. 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 which 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. The addition amount of ethylene carbonate is preferably 10% by mass or more and 90% by mass or less of the total electrolyte solvent mass. 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.

[White scattered matter]
In the present invention, a porous white scattering layer can be provided from the viewpoint of further enhancing display contrast and white display reflectance.

  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.

  In the present invention, “substantially insoluble in an electrolyte solvent” is defined as a state in which the dissolved amount per kg of electrolyte solvent is 0 g or more and 10 g or less at a temperature of −20 ° C. to 120 ° C. The amount of dissolution can be determined by a known method such as a component determination method using a chromatogram or a gas chromatogram.

  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 polysaccharides such as starch, gum arabic, dextran, pullulan and carrageenan, polyvinyl alcohol, polyethylene glycol, polyvinyl pyrrolidone, and acrylamide. Synthetic polymer compounds such as coalescence and derivatives thereof may be mentioned. 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. Furthermore, Research Disclosure and those described in 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 (e.g., sodium methacrylate in the vinyl monomer having a methacrylic acid Copolymers with ammonium, potassium acrylate, etc.) are also used. Two or more of these binders can be used in combination.

  In the present invention, polyvinyl alcohol, polyethylene glycol, and polyvinylpyrrolidone compounds can be preferably used.

  Polymers dispersed in aqueous solvents 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.

  The average molecular weight of the water-based polymer of the present invention is preferably in the range of 10,000 to 2,000,000, more preferably in the range of 30,000 to 500,000 on a weight average basis.

  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 is preferably used. In particular, titanium dioxide surface-treated with an inorganic oxide (Al ₂ O ₃ , AlO (OH), SiO _2, etc.), in addition to these surface treatments. Titanium dioxide that has been treated with an organic substance such as trimethylolethane, triethanolamine acetate, or trimethylcyclosilane is more preferably 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, 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.

  The thickness of the porous white scattering layer is preferably in the range of 5 to 50 μm, more preferably in the range of 10 to 30 μm.

  As the alcohol solvent, a compound having high solubility in water such as methanol, ethanol, isopropanol is preferably used, and the mixing ratio with the water / alcohol solvent is preferably in the range of 0.5 to 20 by mass ratio, More preferably, it is the range of 2-10.

  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.

  As a coating method, it can select suitably from a well-known coating method. For example, air doctor coater, blade coater, rod coater, knife coater, squeeze coater, impregnation coater, reverse roller coater, transfer roller coater, curtain coater, double roller coater, slide hopper coater, gravure coater, kiss roll coater, bead coater, Examples include 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.

〔Electrolytes〕
The “electrolyte” as used in the present invention generally refers to a substance that dissolves in a solvent such as water and exhibits a ionic conductivity in a solution (hereinafter referred to as “narrowly defined electrolyte”). A mixture containing other metals, compounds, or the like, regardless of whether it is an electrolyte or a non-electrolyte, is called an electrolyte (“broadly defined electrolyte”).

  As the electrolyte used in the present invention, salts, acids, and alkalis that are usually used in the field of electrochemistry or the field of batteries can be used.

  There are no particular limitations on the salts, and for example, inorganic ion salts such as alkali metal salts and alkaline earth metal salts; quaternary ammonium salts; cyclic quaternary ammonium salts; quaternary phosphonium salts and the like can be used.

Specific examples of the salts include halogen ions, SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , PF _{^{6 -, AsF 6 -, CH}} 3 COO -, CH 3 (C 6 H 4) SO 3 -, and _{(C 2 F 5 SO 2)} 3 C - Li salt having a counter anion selected from, Na salt or K salt is mentioned.

Also, halogen ions, SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , PF ₆ ⁻ , AsF ₆ ⁻ A quaternary ammonium salt having a counter anion selected from CH ₃ COO ⁻ , CH ₃ (C ₆ H ₄ ) SO ₃ ⁻ , and (C ₂ F ₅ SO ₂ ) ₃ C ⁻ , specifically, (CH ₃ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ NBF ₄ , (n-C ₄ H ₉ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ NBr, (C ₂ H ₅ ) ₄ NClO ₄ , (n-C) ₄ H ₉ ) ₄ NClO ₄ , CH ₃ (C ₂ H ₅ ) ₃ NBF ₄ , (CH ₃ ) ₂ (C ₂ H ₅ ) ₂ NBF ₄ , (CH ₃ ) ₄ NSO ₃ CF ₃ , (C ₂ H _{5 ) 4 NSO 3 CF 3, (} n-C 4 H 9) ₄ NSO ₃ CF ₃ , and a compound represented by the following formula can be given.

Also, halogen ions, SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , PF ₆ ⁻ , AsF ₆ ⁻ , A phosphonium salt having a counter anion selected from CH ₃ COO ⁻ , CH ₃ (C ₆ H ₄ ) SO ₃ ⁻ , and (C ₂ F ₅ SO ₂ ) ₃ C ^— , specifically, (CH ₃ ) _{4 PBF 4, (C 2 H 5} ) 4 PBF 4, (C 3 H 7) 4 PBF 4, include _{(C 4 H 9) 4 PBF} 4 and the like. Moreover, these mixtures can also be used suitably.

The supporting electrolyte of the present invention is preferably a quaternary ammonium salt, particularly preferably a quaternary spiro ammonium salt. The _ClO ⁴ as counter anion ^{_{-, BF 4 -, CF 3}} SO 3 -, (C 2 F 5 SO 2) 2 N -, PF 6 - are preferable, and BF ₄ ^- is preferable.

  The amount of the electrolyte salt used is arbitrary, but in general, the electrolyte salt is desirably present in the solvent as an upper limit of 20 M or less, preferably 10 M or less, more preferably 5 M or less. It is desirable that it be present at 0.01M or more, preferably 0.05M or more, more preferably 0.1M or more.

  In the case of a solid electrolyte, the following compounds showing electron conductivity and ion conductivity can be contained in the electrolyte.

Vinyl fluoride polymer containing perfluorosulfonic acid, polythiophene, polyaniline, polypyrrole, triphenylamines, polyvinylcarbazoles, polymethylphenylsilanes, Cu ² S, Ag ² S, Cu ² Se, AgCrSe ^2, etc. Chalcogenide, CaF ₂ , PbF ₂ , SrF ₂ , LaF ₃ , TlSn ₂ F ₅ , CeF _{3 and} other F-containing compounds, Li ₂ SO ₄ , Li ₄ SiO ₄ , Li ₃ PO _{4 and} other Li salts, ZrO ₂ , CaO , Cd ₂ O ₃ , HfO ₂ , Y ₂ O ₃ , Nb ₂ O ₅ , WO ₃ , Bi ₂ O ₃ , AgBr, AgI, CuCl, CuBr, CuBr, CuI, LiI, LiBr, LiCl, LiAlCl ₄ , LiAlF _{4 , AgSBr, C 5 H 5 NHAg} 5 I 6, Rb 4 Cu1 6 I 7 Examples of the compound include Cl ₁₃ , Rb ₃ Cu ₇ Cl ₁₀ , LiN, Li ₅ NI ₂ , and Li ₆ NBr ₃ .

(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 (fusing method) (using fine pores formed between particles by partially fusing polymer fine particles or inorganic particles by adding a binder, etc.), extraction method ( After forming a constituent layer with a solvent-soluble organic substance or inorganic substance and a binder that does not dissolve in the solvent, the organic substance or inorganic substance is dissolved with the solvent to obtain pores), and the polymer is heated or degassed Known forming methods such as a foaming method in which foaming is performed, a phase change method in which a mixture of polymers is phase-separated by operating a good solvent and a poor solvent, and a radiation irradiation method in which pores are formed by radiating various types of radiation 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 (epoxide) s, 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
〔substrate〕
<Display side transparent substrate>
The substantially transparent substrate used in the present invention is a substrate having a transmittance for visible light of at least 50% or more.

  Examples of such transparent substrates include polyester (for example, polyethylene terephthalate), polyimide, polymethyl methacrylate, polystyrene, polypropylene, polyethylene, polyamide, nylon, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyether sulfone, and silicone resin. Polymer films such as polyacetal resins, fluororesins, cellulose derivatives, polyolefins, plate-like substrates, glass substrates and the like are preferably used.

<Non-display side counter substrate>
As the counter substrate, an opaque substrate such as an inorganic substrate such as a metal substrate or a ceramic substrate can be used in addition to the transparent substrate used for the display-side transparent substrate.

〔electrode〕
<Display side 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 addition, polythiophene, polypyrrole, polyaniline, polyacetylene, polyparaphenylene, polyselenophenylene, etc., and their modifying compounds can be used alone or in combination.

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.
<Transparent porous electrode>
As a transparent electrode, a nanoporous electrode having a nanoporous structure can be provided on the electrode layer. This nanoporous electrode is substantially transparent when a display element is formed, and can carry an electroactive substance such as an electrochromic dye.

  The nanoporous structure as used in the present invention refers to a state in which an infinite number of nanometer-sized pores exist in a layer and ionic species contained in the electrolyte can move within the nanoporous structure.

  As a method for forming such a nanoporous electrode, a dispersion containing fine particles constituting the nanoporous electrode is formed in layers by an ink jet method, a screen printing method, a blade coating method, etc., and then heated at a predetermined temperature. A method of making porous by drying, baking, a method of making nanoporous by anodizing or photoelectrochemical etching after forming an electrode layer by sputtering, CVD, atmospheric pressure plasma, etc. Is mentioned. Also, the sol-gel method, Adv. Mater. It can also be formed by the method described in 2006, 18, 2980-2983.

The main components of the fine particles constituting the nanoporous electrode are metals such as Cu, Al, Pt, Ag, Pd and Au, metal oxides such as ITO, SnO ₂ , TiO ₂ and ZnO, carbon nanotubes, glassy carbon, and diamond. It can be selected from carbon electrodes such as like carbon and nitrogen-containing carbon, and is preferably selected from metal oxides such as ITO, SnO ₂ , TiO ₂ , and ZnO.

  In order for the nanoporous electrode to have transparency, it is preferable to use fine particles having an average particle diameter of about 5 nm to 10 μm. As the shape of the fine particles, those having an arbitrary shape such as an indefinite shape, a needle shape, and a spherical shape can be used.

  The film thickness of the nanoporous electrode is preferably in the range of 0.1 to 10 μm, more preferably in the range of 0.25 to 5 μm.

<Counter electrode>
The counter electrode can be used without particular limitation as long as it conducts electricity.

  In addition to the same material as the transparent electrode, metals having no transparency such as platinum, gold, silver, copper, aluminum, zinc, nickel, titanium, bismuth and the like, alloys thereof, carbon and the like can be preferably used.

[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 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 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 TFT circuits provided in each grid pattern. Since switching can be performed for each pixel, there are merits 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, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

Example 1
<< Production of display element >>
(Preparation of electrolyte)
(Preparation of electrolyte 1)
In 2.5 g of dimethyl sulfoxide, 0.1 g of silver iodide and 0.2 g of sodium iodide were dissolved to obtain an electrolytic solution 1.

(Preparation of electrolyte 2)
In 2.5 g of dimethyl sulfoxide, 0.1 g of silver p-toluenesulfonate and 0.2 g of compound (G-12) were dissolved to obtain an electrolytic solution 2.

(Preparation of electrolyte 3)
In 2.5 g of compound S1-4, 0.1 g of silver p-toluenesulfonate and 0.2 g of compound (G-12) were dissolved to obtain an electrolytic solution 3.

(Preparation of electrolyte 4)
In 2.5 g of compound S1-2, 0.1 g of silver p-toluenesulfonate and 0.2 g of compound (G-12) were dissolved to obtain an electrolytic solution 4.

(Preparation of electrolyte 5)
In 2.5 g of dimethylformamide, 0.1 g of bismuth chloride and 0.2 g of sodium chloride were dissolved to obtain an electrolytic solution 5.

[Production of electrodes]
(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, and a transparent electrode (electrode 1) is formed. Obtained.

(Preparation of electrode 2)
A palladium thin film having a thickness of 20 nm was formed on the surface of the electrode 1 by a sputtering method, and a palladium pattern identical to the ITO pattern of the electrode 1 was formed by a photolithography method to obtain an electrode 2.

(Preparation of electrode 3)
Electrode 1 sufficiently washed with acetone in an ethanol / toluene mixed solution of 1% by mass of n-octadecyltriethoxysilane was immersed for 30 minutes and then heated at 150 ° C. for 20 minutes and treated with n-octadecyltriethoxysilane. 3 was obtained.

(Preparation of electrode 4)
An electrode 4 was obtained in the same manner as in the electrode 3, except that n-octadecyltriethoxysilane was changed to γ-aminopropyltrimethoxysilane.

(Preparation of electrode 5)
An electrode 5 was obtained in the same manner as in the electrode 3 except that n-octadecyltriethoxysilane was changed to γ-mercaptopropyltrimethoxysilane.

(Preparation of titanium dioxide dispersion)
Kuraray Poval PVA235 (manufactured by Kuraray Co., Ltd., polyvinyl alcohol resin) was added to the water / ethanol mixed solution so as to have a solid content concentration of 2% by mass, dissolved by heating, and then titanium dioxide CR-90 made by Ishihara Sangyo Co., Ltd. Was dispersed with an ultrasonic disperser so as to be 20% by mass to obtain a titanium dioxide dispersion.

(Preparation of electrode 6)
On the electrode 1, the titanium dioxide dispersion was screen-printed so that the average film thickness after drying was 20 μm, then dried at 50 ° C. for 30 minutes to evaporate the solvent, and then in an atmosphere at 85 ° C. for 1 hour. The electrode 6 which dried and formed the porous white scattering layer was produced.

(Preparation of electrode 7)
Immobilize Compound M56 by immersing Electrode 4 in a dimethylformamide solution containing 1% by mass of Compound M56 and 0.5% by mass of 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride for 30 minutes. did. On the obtained electrode, the titanium dioxide dispersion was screen-printed so that the average film thickness after drying was 20 μm, then dried at 50 ° C. for 30 minutes to evaporate the solvent, and then in an atmosphere at 85 ° C. An electrode 7 having a porous white scattering layer formed by drying for 1 hour was produced.

(Preparation of electrode 8)
An electrode 8 was obtained in the same manner as in the electrode 7, except that the compound M56 was changed to the compound M9.

(Preparation of electrode 9)
An electrode 9 was obtained in the same manner as in the electrode 7, except that the compound M56 was changed to the compound M74.

[Production of display element]
(Preparation of display element 1)
After the periphery of the electrode 3 is edged with an olefin-based sealant containing glass spherical beads having an average particle diameter of 40 μm as a volume fraction of 10%, the striped electrodes are orthogonal to the electrodes 3 and 1 respectively. The cells were bonded together and further heated and pressed to produce an empty cell. The electrolytic 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.

(Production of display elements 2 to 11)
Display elements 2 to 11 were produced using combinations of electrodes and electrolytes described in Table 1.

<< Evaluation of display element >>
[Evaluation of rewriting speed]
Konica Minolta sensing the reflectance of 550 nm wavelength when both electrodes of the display element are connected to both terminals of the constant voltage power supply and a constant voltage of -1.5 V is applied to the display side electrode for 1 second to display in gray measured at company manufactured spectrocolorimeter CM-3700d, the obtained value was defined as _{R BK.} Here, as the value of R _BK is small, resulting in faster rewriting speed of the black display.

[Evaluation of reflectance stability when driven repeatedly (drive stability)]
When both electrodes of the display element are connected to both terminals of the constant voltage power source, a voltage of +1.5 V is applied for 1 second, and then a voltage of -1.5 V is applied for 0.5 second to display gray The reflectance at a wavelength of 550 nm 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 value of the obtained reflectances was defined as R _ave1 . Further, after driving repeatedly 10,000 times, R _ave2 was obtained by the same method. Δ _BK1 = | R _ave1 −R _ave2 | was set as an index of stability of reflectance when ΔR _BK1 was repeatedly driven. Here, the smaller the value of ΔR _BK1, the better the stability of the reflectance when driven repeatedly.

  Table 1 shows the configurations and evaluation results of the display elements obtained as described above.

  It can be seen that the configuration of the present invention is very excellent in stability when driven repeatedly.

Claims (7)

Between the counter electrodes, there is an electrolyte layer containing at least one of a metal salt compound and a compound represented by the following general formula (G-2), and the electrode on the side where the display can be seen is a silane cup An auxiliary compound that is modified with a ring agent and that can be oxidized / reduced is fixed to an electrode on the side opposite to the electrode on which the display can be seen, and black is applied by applying a voltage between the counter electrodes. An electrochemical display element characterized by displaying white.

[Wherein Z represents an atomic group necessary for constituting a nitrogen-containing heterocyclic ring. n represents an integer of 0 to 5, Rg ₂₁ represents a substituent, and when n is 2 or more, each Rg ₂₁ may be the same or different, and may be connected to each other to form a condensed ring. It may be formed. ] When the molar concentration of metal ions in the metal salt compound is [Metal] (mol / kg) and the total molar concentration of halogen ions or halogen atoms of halogen molecules is [x] (mol / kg), 0 <[ The electrochemical display element according to claim 1, wherein a condition of x] / [Metal] ≦ 0.01 is satisfied. The electrochemical display element according to claim 1, wherein the metal salt compound is a silver salt compound. The electrochemical display element according to claim 1, wherein the silane coupling agent has a —SH group. The electrochemical display element according to claim 1, wherein the auxiliary compound is a ferrocene derivative. The electrochemical display element according to claim 1, wherein the auxiliary compound is an N oxyl derivative. The electrochemical display according to any one of claims 1 to 6, wherein the electrolyte layer contains at least one selected from compounds represented by the following general formulas (S1) and (S2). element.

[Wherein L represents an oxygen atom or an alkylene group, and Rs ₁₁ to Rs ₁₄ 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 Rs ₂₁ and Rs ₂₂ each represents an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group or an alkoxy group. ]