JP2010256436A - Electrochemical display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrochemical display element which has high response speed and low electric charge consumption. <P>SOLUTION: The electrochemical display element has an electrolyte layer which contains a silver salt compound, between a pair of electrodes which face each other, and conducts operation for driving the pair of electrodes which face each other so that the silver salt compound is in a silver-ion state or a silver-deposited state. In addition, the display element contains, in the electrolyte layer, at least one of compound which can form a self assembled layer on the deposited silver. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrochemical display element, and more particularly to an 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 means of browsing, 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, and restricted reading posture In addition, 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 that compensates for these drawbacks, a reflection type display that uses external light and does not consume power for image retention (memory type) is known, but has sufficient performance for the following reasons. It's hard to say.

  That is, the 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 production 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 need for a complicated TFT circuit 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 that eliminates the drawbacks of each of the above-described methods, an electrodeposition (hereinafter abbreviated as ED) method that utilizes dissolution or precipitation of a metal or a 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 and white contrast and black quality, and various methods have been disclosed (for example, Patent Documents 1 to 3). 4).

  As a result of examining the techniques disclosed in each of the above patent documents in detail, the present inventor has found that there are significant problems in response speed and charge consumption. In addition, no reference is made to the problems of response speed and charge consumption. In response to the above problems, an electrochemical display element containing ethylenethiourea as a deposition accelerator in an electrolyte has been disclosed (for example, see Patent Document 5). However, as a result of examining the techniques disclosed in the above-mentioned patent documents in detail, it has been found that improvement in response speed and reduction in the amount of electric charge consumed are still insufficient.

U.S. Pat. No. 4,240,716 Japanese Patent No. 3428603 JP 2003-241227 A Japanese Patent Laid-Open No. 2005-266652 JP 2005-338515 A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an electrochemical display element (hereinafter also simply referred to as a display element) having a high response speed and a small amount of electric charge consumption.

  The above object of the present invention can be achieved by the following configuration.

  1. There is an electrolyte layer containing a silver salt compound between a pair of opposing electrodes, and the driving operation of the pair of opposing electrodes is performed so that the silver salt compound is in a silver ion state and a precipitated silver state. A display device to be performed, wherein the electrolyte layer includes at least one compound capable of forming a self-assembled film on the deposited silver.

  2. 2. The electrochemical display element according to 1 above, wherein the compound capable of forming the self-assembled film is represented by the following general formula (1).

[Wherein, R ₁ is any _one of an aliphatic hydrocarbon group having 13 to 20 carbon atoms, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a perfluoroalkyl group. L is a divalent linking group. Z represents an atomic group necessary for forming a nitrogen-containing heterocycle. n represents an integer of 0 to 5. R ₂ represents a hydrogen atom or a substituent. ]
3. 3. The electrochemical display device according to 2, wherein R _{1 in the} general formula (1) is a linear alkyl group.

  4). 4. The electrochemical display element as described in 2 or 3 above, wherein Z in the general formula (1) is a triazole ring.

  5. Any of the above items 2 to 4, wherein the compound represented by the general formula (1) is contained in the electrolyte layer in a mass ratio of 5% or more and 30% or less with respect to the total mass of the electrolyte layer. The electrochemical display element of Claim 1.

  According to the present invention, by containing at least one compound capable of forming a self-assembled film on the deposited silver, the dissolution and precipitation of the silver salt compound is smoothed, the response speed is improved, and the charge consumption is reduced. A display element could be provided.

  The present invention will be described in more detail.

  Hereinafter, the display element of the present invention will be specifically described. However, the present invention is not limited to the following examples, and a conventionally known configuration can be added as appropriate, and does not depart from the gist of the present invention.

[Basic structure of display element]
The display element of the present invention has a pair of opposing electrodes, a display-side electrode near the display unit is provided with a transparent electrode such as an ITO electrode, and the other counter electrode is provided with a metal electrode such as a silver electrode. Yes. An electrolyte layer containing a silver salt compound is provided between both electrodes, and by applying a voltage of both positive and negative polarity between both electrodes, an oxidation-reduction reaction of the silver salt compound is performed, and precipitated silver (black The state (reduced state) of silver halide) and the state (oxidized state) of transparent silver ions can be switched reversibly.

  The display element of the present invention is characterized in that the electrolyte layer contains at least one compound capable of forming a self-assembled film on the deposited silver (hereinafter also referred to as deposited silver).

  Hereinafter, the components will be sequentially described.

[Compound capable of forming a self-assembled film on precipitated silver]
The self-assembled film according to the present invention is an abbreviation for a self-assembled monolayer, and refers to a film in which a compound having high orientation is formed on precipitated silver. The compound capable of forming a self-assembled film on the precipitated silver according to the present invention is a compound in which a site that interacts with precipitated silver and a site that does not interact with precipitated silver are linked. The film pressure of the self-assembled film can be easily adjusted by the size of the part that does not interact with the precipitated silver. The formation of the self-assembled film can be confirmed by the method described in JP-A No. 2005-172882.

  The detailed action of the compound capable of forming a self-assembled film on the precipitated silver is considered as follows, but is not limited to this principle.

  When a silver salt compound is deposited on the surface of the display-side electrode by applying a voltage, the part of the compound that interacts with the precipitated silver is adsorbed to the precipitated silver, and the part that does not interact with the precipitated silver is perpendicular to the surface of the precipitated silver. A self-assembled film is formed by orienting. For this reason, it is suppressed that the precipitated silver grows greatly in the direction perpendicular to the electrode surface, and the growth of the precipitated silver in the horizontal direction with respect to the electrode surface is promoted. This shortens the time required for the precipitation to reach a certain concentration and improves the blackening rate. In addition, since the amount of charge consumed until the precipitation reaches a certain concentration is proportional to the amount of precipitated silver, the amount of charge consumed can be reduced. On the other hand, when the reverse voltage is applied to dissolve the precipitated silver, the whitening rate is improved because the required amount of dissolved silver is small.

  The compound capable of forming a self-assembled film on the precipitated silver is not particularly limited as long as it is a compound in which a site that interacts with the precipitated silver and a site that does not interact with the precipitated silver are connected. Since it can be coordinated with silver, the site that interacts with the precipitated silver preferably contains a sulfur atom or a nitrogen atom. On the other hand, it is preferable that the site | part which does not interact with precipitation silver does not contain a sulfur atom or a nitrogen atom. Specific examples of compounds that can form a self-assembled film on the precipitated silver are shown below, but the present invention is not limited to these.

  As the compound that forms a self-assembled film on the precipitated silver, the compound represented by the general formula (1) that interacts strongly with the precipitated silver is particularly preferable.

In the compound represented by the general formula (1), a sulfur atom and a nitrogen-containing heterocycle are sites where the precipitated silver interacts, and R ₁ is a site where the precipitated silver does not interact. L is a linking group of both. JP-A-2005-266652 describes that the sulfur atom of the compound represented by the general formula (1) and the nitrogen-containing heterocycle strongly interact with precipitated silver.

  In the general formula (1), examples of the nitrogen-containing heterocycle having Z as a constituent include tetrazole ring, triazole ring, imidazole ring, oxadiazole ring, thiadiazole ring, indole ring, oxazole ring, benzoxazole ring, and benzine. Examples include an imidazole ring, a benzothiazole ring, a benzoselenazole ring, and a naphthoxazole ring. In order to form a self-assembled monolayer on the deposited silver, a triazole ring is particularly preferable.

In the general formula (1), R ₁ is any _one of an aliphatic hydrocarbon group having 13 to 20 carbon atoms, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a perfluoroalkyl group.

  Examples of the aliphatic hydrocarbon group include alkyl groups (for example, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, octadecyl group, icosyl group, etc.), alkenyl groups (for example, hexadecenyl group, octadecenyl group, etc.), alkynyl groups (for example, , Hexadecynyl group, octadecynyl group, etc.). Examples of the alicyclic hydrocarbon group include a cycloalkyl group (for example, a cyclohexadecanyl group). Examples of the aromatic hydrocarbon group include a pyrenyl group. Examples of the perfluoroalkyl group include a perfluorotridecyl group, a perfluorohexadecyl group, and a perfluorooctadecyl group.

  In order to form a self-assembled film on the deposited silver, a self-assembled film cannot be formed if the number of carbon atoms is too small. On the other hand, when the number of carbon atoms is too large, the solubility in a solvent is lowered, so that a carbon number of 20 or less is suitable. In particular, a linear alkyl group having 13 to 20 carbon atoms is preferable.

In the general formula (1), R ₂ is a hydrogen atom or a substituent. Although there is no restriction | limiting in particular as a substituent, For example, the following substituents are mentioned.

  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.

In the general formula (1), L is a divalent linking group. Although there is no particular limitation, for example, an alkylene group (for example, a methylene group, an ethylene group, a propylene group, etc.) and an arylene group (for example, a phenylene group, a naphthylene group, etc.). Alternatively, it may be a composite group of these with —O—, —CO—, —COO—, —CONH—, —SO ₂ —, and the like. Furthermore, you may have substituents, such as a hydroxyl group, an alkoxy group, and an amino group.

  Specific examples of the compound represented by the general formula (1) are shown below, but the present invention is not limited thereto.

  In order to smoothly deposit and dissolve the silver salt compound on the electrode, the amount of the compound that forms the self-assembled film on the deposited silver is 1% or more with respect to the total mass of the electrolyte layer, 50% % Or less is preferred. More preferably, the mass ratio is 5% or more and 30% or less with respect to the total mass of the electrolyte layer.

[Silver salt solvent]
In the present invention, a silver salt solvent can be used to promote dissolution and precipitation of the silver salt. The silver salt solvent may be any compound that can solubilize silver in the electrolyte. For example, it is common to use a means for converting a silver salt compound into a solubilized product in the presence of a compound containing a chemical structural species that interacts with the silver salt compound that causes a coordinate bond with silver ions. Is. As the chemical species, halogen atoms, mercapto groups, carboxyl groups, imino groups, and the like are known, but in the present invention, compounds containing thioether groups and mercaptoazoles have the effect of solubilizing silver salt compounds. It is characterized by high solubility in a solvent with little influence on coexisting compounds.

  Although the silver salt solvent of this invention is not limited, The compound represented by following General formula (2) is especially preferable.

In the general formula (2), M represents a hydrogen atom, a metal atom or quaternary ammonium. Z ₁ represents an atomic group necessary for forming a nitrogen-containing heterocyclic ring. n represents an integer of 0 to 5. R ₃ represents a hydrogen atom or a substituent. When n is 2 or more, each R ₃ may be the same or different, and may be linked to each other to form a condensed ring.

Examples of the metal atom represented by M in the general formula (2) include Li, Na, K, Mg, Ca, Zn, and Ag. 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 It is done.

Examples of the nitrogen-containing heterocyclic ring having Z ₁ in the general formula (2) as a constituent component 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 benzine. Examples include an imidazole ring, a benzothiazole ring, a benzoselenazole ring, and a naphthoxazole ring.

R _{3 in the} general formula (2) is a hydrogen atom or a substituent. Although there is no restriction | limiting in particular as a substituent, For example, the following substituents are mentioned.

  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 (2) is shown, this invention is not limited to these compounds.

  Among the above-exemplified compounds, Exemplified Compounds 2-12 and 2-20 are particularly preferable from the viewpoint that the object and effects of the present invention can be exhibited.

[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. There are no particular restrictions on the phase state species 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.

  In the display element of the present invention, silver iodide, silver chloride, silver bromide, silver oxide, silver sulfide, silver citrate, silver acetate, silver behenate, silver p-toluenesulfonate, silver trifluoromethanesulfonate, mercapto A known silver salt compound such as a silver salt with an acid or a silver complex with iminodiacetic acid can be used. Among these, it is preferable to use, as a silver salt, a compound that does not have a nitrogen atom having coordination properties with halogen, carboxylic acid, or silver, and for example, silver p-toluenesulfonate is preferable.

  The metal ion concentration contained in the electrolyte according to the present invention is preferably 0.2 mol / kg ≦ [Metal] ≦ 2.0 mol / kg. If the metal ion concentration is 0.2 mol / kg or more, a silver solution having a sufficient concentration can be obtained, and a desired driving speed can be obtained. If the metal ion concentration is 2 mol / kg or less, precipitation is prevented, and storage at low temperature is possible. The stability of the electrolyte solution is improved.

[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 greater 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.

[Organic 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, particularly preferably used solvents are compounds represented by the following general formulas (S1) and (S2).

[Compounds Represented by General Formulas (S1) and (S2)]
In the display element of the present invention, the electrolyte preferably contains a compound represented by the following general formula (S1) or (S2).

In the formula, L ₁ 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 formula, 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 ₁ 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, 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.

  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, or cellulose derivatives, natural compounds such as starch, gum arabic, dextran, pullulan, and carrageenan polysaccharides, polyvinyl alcohol, polyethylene glycol, polyvinyl pyrrolidone, and acrylamide polymers. And synthetic polymer compounds such as derivatives thereof. 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 of the vinyl monomer having a (e.g., sodium methacrylate, Copolymers with ammonium acid, potassium acrylate, etc.) are also used. These binders can be used in combination of two or more.

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

  Polymers dispersed in an aqueous solvent include latexes such as natural rubber latex, styrene butadiene rubber, butadiene rubber, nitrile rubber, chloroprene rubber, isoprene rubber, polyisocyanate, epoxy, acrylic, silicon, 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.

〔Electrolytes〕
As the supporting electrolyte that can be used in the electrolyte composition of 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.

Further, 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 - 4 quaternary ammonium salt having a counter anion selected from, 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,
Furthermore,

Etc.

Further, 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 - phosphonium salt having a counter anion selected from, specifically, _(CH 3) ₄ PBF ₄ , (C ₂ H ₅ ) ₄ PBF ₄ , (C ₃ H ₇ ) ₄ PBF ₄ , (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 amount of the electrolyte salt used is arbitrary, but in general, the electrolyte salt is present in the solvent as an upper limit of 20 mol / L or less, preferably 10 mol / L or less, more preferably 5 mol / L or less. The lower limit is usually 0.01 mol / L or more, preferably 0.05 mol / L or more, more preferably 0.1 mol / L or more.

[Solid electrolyte, gel electrolyte]
The electrolyte according to the present invention is not only a solution electrolyte composed of a solvent or an ionic liquid, but also a high-viscosity electrolyte or gel electrolyte (hereinafter, referred to as a solid electrolyte or a polymer compound containing substantially no solvent). Gel electrolyte) can be used.

  Examples of the solid electrolyte and gel electrolyte applicable to the present invention include a solid electrolyte described in JP-A No. 2002-341387, a polymer solid electrolyte described in JP-A No. 2002-341387, and JP-A No. 2004-20928. A solid polymer electrolyte described in JP-A No. 2004-191945, a solid polymer electrolyte described in JP-A No. 2005-338204, and a polymer described in JP-A No. 2006-323022 Examples thereof include solid electrolytes, solid electrolytes described in JP-A No. 2007-141658, solid electrolytes described in JP-A No. 2007-163865, and gel electrolytes.

[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.

  In the display element of the present invention, polyethylene glycol having an average polymerization degree of 100 to 500 is preferable as the thickener, and it is preferably added in a range of 5 to 20% by mass ratio with respect to the organic solvent of the electrolyte layer. .

〔substrate〕
The substrate that can be used in the present invention is preferably a transparent substrate. Examples of such a transparent substrate include polyester (for example, polyethylene terephthalate), polyimide, polymethyl methacrylate, polystyrene, polypropylene, polyethylene, and polyamide. Nylon, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyether sulfone, silicon resin, polyacetal resin, fluororesin, cellulose derivative, polyolefin and other polymer films, plate substrates, glass substrates, and the like are preferably used. The transparent substrate used in the present invention refers to a substrate having a transmittance for visible light of at least 50%.

  Further, as the counter substrate, for example, an opaque substrate such as an inorganic substrate such as a metal substrate or a ceramic substrate can be used.

〔electrode〕
A pair of opposing electrodes used in the present invention is composed of an electrode located on the display side (hereinafter referred to as a display side electrode) and an electrode located on the opposite side across the electrolyte layer (hereinafter referred to as a counter electrode). Become.

"Display side electrode"
A transparent electrode that transmits at least visible light is used for the display-side electrode. 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 indicating the conductivity of the display-side electrode is preferably 100Ω / or less, and more preferably 10Ω / or less. Although there is no restriction | limiting in particular in the thickness of an electrode, it is common that it is 0.1-20 micrometers.

"Transparent porous electrode" (conductive)
A nanoporous electrode having a nanoporous structure can be provided on the surface of the display side electrode. 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 referred to 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"
Since the counter electrode can be used without being involved in the display color, it can be used without particular limitation as long as it conducts electricity.

  In addition to the same materials used for the display-side electrode, metals such as platinum, gold, silver, copper, aluminum, zinc, nickel, titanium, bismuth and their alloys, carbon, etc. are also preferably used. be able to.

"Porous carbon electrode" (special)
Porous carbon electrodes that can be adsorbed and supported include graphite, non-graphitizable carbon, graphitizable carbon, composite carbon, and carbon compounds obtained by doping carbon with boron, nitrogen, phosphorus, etc. Can be mentioned. Examples of the shape of the carbon particles include mesophase microspheres and fibrous graphite. Mesophase spherules can be obtained by firing coal tar pitch or the like at 350 to 500 ° C., and further classifying these spherules and graphitizing by high-temperature firing can provide a good porous carbon electrode. In addition, fibrous graphite can be obtained from pitch-based, PAN-based, and vapor-grown fibers.

"Auxiliary electrode"
An auxiliary electrode can be attached to at least one of the pair of opposing electrodes according to the present invention.

  The auxiliary electrode is preferably made of a material having a lower electrical resistance than the main electrode portion. For example, metals such as platinum, gold, silver, copper, aluminum, zinc, nickel, titanium, and bismuth and alloys thereof can be preferably used.

  The auxiliary electrode can be installed either between the main electrode portion and the substrate, or on the surface of the main electrode portion opposite to the substrate. In any case, it is only necessary that the auxiliary electrode is electrically connected to the main electrode portion.

  There are no particular restrictions on the arrangement pattern of the auxiliary electrodes. It can be appropriately formed according to the required performance, such as linear, mesh, or circular. When the main electrode part is divided into a plurality of parts, the divided electrode parts may be connected to each other. However, in the case where the main electrode portion is a transparent electrode provided on the substrate on the display side, the auxiliary electrode is required to be provided with a shape and frequency that do not impair the visibility of the display element.

  As a method of forming the auxiliary electrode, a known method can be used. For example, patterning may be performed by a photolithography method, a printing method, an ink jet method, electrolytic plating or electroless plating, or a method of forming a pattern by exposing and developing using a silver salt photosensitive material.

  Although the line width and line interval of the auxiliary electrode pattern of the present invention may be arbitrary values, it is necessary to increase the line width in order to increase the conductivity. On the other hand, when an auxiliary electrode is attached to the transparent electrode, from the viewpoint of visibility, the area coverage of the auxiliary electrode viewed from the display element observation side is preferably 30% or less, and more preferably 10% or less.

  Thus, from the viewpoint of transmittance and conductivity, the line width of the auxiliary electrode is preferably 1 μm or more and 100 μm or less, and the line interval is preferably 50 μm to 1000 μm.

(Production method of electrodes)
A known method can be used to form the display side electrode and the counter electrode. For example, mask deposition may be performed on the substrate by sputtering or the like, or patterning may be performed by photolithography after the entire surface is formed.

  Electrodes can also be formed by electrolytic plating, electroless plating, printing methods, and ink jet methods.

  After forming an electrode pattern including a catalyst layer having a monomer polymerization ability on a substrate using an inkjet method, a monomer component that is polymerized by the catalyst and becomes a conductive polymer layer after polymerization is added, It is also possible to form a metal electrode pattern by polymerizing and further performing metal plating such as silver on the conductive polymer layer, and the process is greatly reduced because no photoresist or mask pattern is used. It can be simplified.

  When the electrode material is formed by coating, known methods such as a dipping method, a spinner method, a spray method, a roll coater method, a flexographic printing method, and a screen printing method can be used.

  Among the inkjet methods, the following electrostatic inkjet can print a highly viscous liquid continuously with high accuracy and is preferably used for forming the transparent electrode and the metal auxiliary electrode of the present invention. The viscosity of the ink is preferably 30 mPa · s or more, and more preferably 100 mPa · s or more.

(Electrostatic inkjet)
In the display element of the present invention, at least one of the pair of opposed electrodes has a liquid discharge head having a nozzle having an internal diameter of 30 μm or less for discharging a charged liquid, and a supply means for supplying a solution into the nozzle. Preferably, it is formed by using a liquid discharge apparatus provided with discharge voltage application means for applying a discharge voltage to the solution in the nozzle.

  Furthermore, it is preferable that the solution in the nozzle is formed using a discharge device provided with a convex meniscus forming means for forming a state where the solution rises in a convex shape from the nozzle tip.

  In addition, an operation control unit that controls application of a drive voltage for driving the convex meniscus forming unit and application of a discharge voltage by the discharge voltage application unit is provided, and the operation control unit applies the discharge voltage by the discharge voltage application unit. It is also preferable to use a liquid ejection apparatus having a first ejection control unit that applies a driving voltage to the convex meniscus forming means when ejecting liquid droplets while performing the above.

  In addition, an operation control unit that controls driving of the convex meniscus forming unit and voltage application by the discharge voltage applying unit is provided, and the operation control unit is configured to swell the solution by the convex meniscus forming unit and apply the discharge voltage. And a second discharge control unit that performs synchronization with the liquid discharge device, wherein the operation control means is configured to supply the liquid at the tip of the nozzle after the swell operation of the solution and the application of the discharge voltage. It is also a preferred form to use a liquid ejection apparatus having a liquid level stabilization control unit that performs operation control for drawing the surface inward.

  By producing an electrode pattern using such an electrostatic inkjet, it is advantageous that an electrode having excellent on-demand characteristics, little waste material, and excellent dimensional accuracy can be obtained.

(Electronic insulation layer)
In the display element of the present invention, an electronic 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.

[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 region 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.

[Screen printing, display element manufacturing method]
In the present invention, a sealant, a columnar structure, an electrode pattern, and the like can be formed by a screen printing method. In the screen printing method, a screen on which a predetermined pattern is formed is placed on an electrode surface of a substrate, and a printing material (a composition for forming a columnar structure, such as a photocurable resin) is placed on the screen. Then, the squeegee is moved at a predetermined pressure, angle, and speed. Thereby, the printing material is transferred onto the substrate through the pattern of the screen. Next, the transferred material is heat-cured and dried. When the columnar structure is formed by the screen printing method, the resin material is not limited to a photocurable resin, and for example, a thermosetting resin such as an epoxy resin or an acrylic resin or a thermoplastic resin can also be used. As thermoplastic resins, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, polymethacrylate resin, polyacrylate resin, polystyrene resin, polyamide resin, polyethylene resin, polypropylene resin, fluororesin, polyurethane resin , Polyacrylonitrile resin, polyvinyl ether resin, polyvinyl ketone resin, polyether resin, polyvinyl pyrrolidone resin, saturated polyester resin, polycarbonate resin, chlorinated polyether resin and the like. The resin material is preferably used in the form of a paste by dissolving the resin in an appropriate solvent.

  After the columnar structure or the like is formed on the substrate as described above, a spacer is provided on at least one of the substrates as desired, and the pair of substrates are overlapped with the electrode formation surfaces facing each other to form an empty cell. . A pair of stacked substrates is heated while being pressed from both sides, whereby the display cells are obtained. In order to obtain a display element, an electrolyte composition may be injected between substrates by a vacuum injection method or the like. Alternatively, when the substrates are bonded together, the electrolyte composition may be dropped on one substrate, and the liquid crystal composition may be sealed simultaneously with the bonding of the substrates.

[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 manufactured by the method for manufacturing a display element of the present invention can be used in the electronic book field, the ID card related field, the public related field, the transportation related field, the broadcasting related field, the settlement related field, the distribution logistics related field and the like. it can. 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, Case decoration of various equipment such as cash card, credit card, highway card, driver's license, hospital examination card, electronic medical record, health insurance card, basic resident register, passport, one-time password, e-book, mobile phone cover, Examples include a keyboard display, an electronic shelf label, an electronic POP, and an electronic advertisement. In particular, it is effective for manufacturing electronic books, electronic advertisements, electronic POPs, and the like that require display on a large screen.

  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
<< Preparation of Electrolytic Solution 1 >>
0.3 g of silver p-toluenesulfonate is added to 5 g of dimethyl sulfoxide (DMSO), then 0.6 g of compound 2-12, 1 g of compound 1 capable of forming a self-assembled film on the deposited silver, p- 0.1 g of toluenesulfonic acid spiro- (1,1 ′)-bipyrrolidinium was added, dissolved, and mixed, and 3 g of titanium dioxide was added and dispersed to obtain an electrolytic solution 1.

<< Preparation of electrolytes 2 to 26 >>
Electrolytic solutions 2 to 26 were prepared in the same manner as in the electrolytic solution 1 except that the compound 1 capable of forming a self-assembled film on the precipitated silver and the addition amount thereof were changed as shown in Table 1, respectively.

<Production of electrode>
Non-display side (counter electrode side pixel) electrode A silver palladium thin film was formed by a known method so as to have a thickness of 1000 nm in the same pattern on the surface ITO opening of a 4 cm × 5 cm drive circuit board. A non-display-side electrode was formed by forming an acrylic resin-based insulating film to a thickness of 500 nm at portions other than the necessary electrode opening.

Display-side electrode ITO was formed to a thickness of 800 nm on a non-alkali glass (thickness: 1.5 mm) surface having a size of 4 cm × 5 cm by a known method.

<< Production of display elements 1 to 26 >>
On the periphery of the non-display-side electrode, after printing an olefin-based sealant containing 10% glass spherical bead spacer having an average particle diameter of 40 μm as a volume fraction, It was dripped at the center part of the display side electrode. Then, the inside of the vacuum bonding apparatus is evacuated, the display side electrode ITO glass and the non-display side electrode are overlapped, the ends are bonded with a sealing material, and then irradiated with UV light of 10 mW / cm ² for 1 minute. Then, the sealing material was cured, and display elements 1 to 26 were produced.

<< Evaluation of display element >>
[Evaluation of response speed and charge consumption]
Both electrodes of each display element produced were connected to both terminals of a constant voltage power source, and the reflectance (R _b ) before voltage application was first measured.

Thereafter, the reflectance (R _a ) after voltage application was measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing while applying a voltage of −1.5 V to the electrode on the display side.

The time when R _b / R _a = 10 was defined as the blackening time, and the amount of charge consumed until then was measured.

Thereafter, a voltage of 1.5 V was applied to the electrode on the display side, and the time until the reflectance reached the initial _Rb was defined as the whitening time and evaluated. The obtained results are shown in Table 1.

  As shown in Table 1, the display elements 1 to 24 using a compound capable of forming a self-assembled film on the precipitated silver have a whitening / blackening rate higher than that of the display element 25 not including the compound. The amount of charge consumed has been reduced. From this, it was found that the use of the compound has the effect of increasing the whitening / blackening speed and reducing the amount of charge consumed. In addition, the display element 26 using ethylenethiourea specified in Japanese Patent Application Laid-Open No. 2005-338515 has improved the blackening speed and reduced the amount of electric charge consumed, but has the same effect as the display element of the present invention. I couldn't.

Among them, the display elements 9 to 23 showed good results, and it was found that the compound represented by the general formula (1) is preferable as the compound. The display elements 12, 13, 14, 16, and 17 showed particularly good results. The whitening / blackening speed was improved by about 2 to 3 times, and the amount of electric charge consumed was reduced to about one third. did. From this, it was found that Z of the compound represented by the general formula (1) is preferably a triazole ring, and R ₂ is preferably a linear alkyl group. Moreover, the display element 12 showed the result better than the display element 24, and it turned out that it is preferable that the quantity of this compound contains 5% or more with respect to the quantity of electrolyte.

Claims (5)

  There is an electrolyte layer containing a silver salt compound between a pair of opposing electrodes, and the driving operation of the pair of opposing electrodes is performed so that the silver salt compound is in a silver ion state and a precipitated silver state. A display device to be performed, wherein the electrolyte layer contains at least one compound capable of forming a self-assembled film on the deposited silver. The electrochemical display element according to claim 1, wherein the compound capable of forming the self-assembled film is represented by the following general formula (1).

[Wherein, R ₁ is any _one of an aliphatic hydrocarbon group having 13 to 20 carbon atoms, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a perfluoroalkyl group. L is a divalent linking group. Z represents an atomic group necessary for forming a nitrogen-containing heterocycle. n represents an integer of 0 to 5. R ₂ represents a hydrogen atom or a substituent. ] The electrochemical display element according to claim 2, wherein R _{1 in the} general formula (1) is a linear alkyl group.   4. The electrochemical display element according to claim 2, wherein Z in the general formula (1) is a triazole ring.   The compound represented by the general formula (1) is contained in the electrolyte layer in a mass ratio of 5% to 30% with respect to the total mass of the electrolyte layer. The electrochemical display element of any one of Claims.