JP2010117635A - Display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display element capable of performing low voltage driving and having excellent driving durability with a simple member construction. <P>SOLUTION: In the display element including an auxiliary compound layer disposed in contact with a non-display side electrode and an electrolyte layer containing a metal salt compound and a 6 to 18 membered saturated heterocycle compound represented by general formula (G1) between facing electrodes, black and white colors are displayed by applying voltage between the facing electrodes. <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 human-friendly means. Generally, as a disadvantage of the light-emitting display, 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). To 3). In the ED system, a method of adding an auxiliary compound that can be oxidized / reduced to the electrolyte is disclosed in order to stabilize the oxidation-reduction reaction and to stabilize the display (see, for example, Patent Document 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 is a problem in the stability of the reflectance when the conventional technique is repeatedly driven.
U.S. Pat. No. 4,240,716 Japanese Patent No. 3428603 JP 2003-241227 A JP 2005-189299 A

  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 durability.

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

  1. An auxiliary compound layer disposed between the counter electrodes in contact with the non-display side electrode; an electrolyte layer containing a metal salt compound and a 6-18 membered saturated heterocyclic compound represented by the following general formula (G1); And displaying black and white by applying a voltage between the counter electrodes.

[In formula, R < ₁ >, R < ₂ > represents the substituent except a hydrogen atom or an amino group, respectively. n represents an integer of 1 to 3, and m represents an integer of 2 to 9. When m is 2 or more, n may be the same or different. ]
2. 2. The display element according to 1 above, wherein the auxiliary compound layer contains an N-oxyl derivative or a ferrocene derivative.

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

  4). A compound represented by the following general formula (L) is contained between the counter electrodes, and color display other than black and white is performed in addition to white display and black display by a driving operation of the counter electrode. The display element according to any one of 1 to 3 above.

[Wherein, Rl ₁ represents a substituted or unsubstituted aryl group, and Rl ₂ and Rl ₃ each represent a hydrogen atom or a substituent. X represents> N—Rl ₄ , an oxygen atom or a sulfur atom, and Rl ₄ represents a hydrogen atom or a substituent. ]
5). The compound represented by the said general formula (L) is -COOH, -P = O (OH) ₂ , -OP = O (OH) _2, and -Si (OR) ₃ (R represents an alkyl group.) 5. The display element according to 4 above, which has at least one substituent selected from the group consisting of:

  6). 6. The display element according to 4 or 5, wherein the compound represented by the general formula (L) is immobilized on the surface of at least one counter electrode.

  According to the present invention, it is possible to provide a display element that has a simple member configuration, can be driven at a low voltage, and has excellent driving durability.

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

  As a result of intensive studies in view of the above problems, the present inventor is represented by the auxiliary compound layer disposed in contact with the non-display side electrode between the counter electrodes, the metal salt compound, and the general formula (G1). An electrolyte layer containing a 6- to 18-membered saturated heterocyclic compound and applying a voltage between the counter electrodes to display black and white; It has been found that a display element that can be driven with a member structure and a low voltage and that has excellent driving stability can be realized.

  In other words, when the metal is dissolved / deposited on the display electrode by the driving operation of the counter electrode, the auxiliary compound disposed in the vicinity of the non-display electrode is correspondingly reduced and oxidized, so that oxidation within the device is performed. It is considered that the reduction reaction is stabilized and the display is stabilized. However, when a compound that is more likely to be oxidized (or reduced) than an auxiliary compound is used as a compound that is added as a silver solvent, the compound that is added as a silver solvent without the auxiliary compound being oxidized (or reduced) at the non-display electrode is the first. It will be oxidized (or reduced). Then, since the auxiliary compound does not function effectively, the oxidation-reduction reaction in the element becomes unstable, and it is considered that the stability of the reflectance when repeatedly driven is impaired. Here, being more easily oxidized (or reduced) means that the oxidation potential is base (or the reduction potential is noble) or kinetically more electrochemically oxidized (or reduced). In the present invention, the compound represented by the general formula (G1) is used as the compound added as the silver solvent. However, this compound is not easily oxidized and reduced on the electrode, and is disposed close to the non-display electrode. In order not to prevent the auxiliary compound from functioning effectively, it is assumed that the stability of the reflectance when it is repeatedly driven is improved.

  Next, details of each component of the display element of the present invention will be described.

[Basic structure of display element]
In the display element of the present invention, the counter electrode (non-display side electrode) that is paired with the display side electrode is provided with a conductive electrode on which an auxiliary compound that can be oxidized and reduced is fixed. Moreover, it has the electrolyte containing the metal salt compound which concerns on this invention, and the 6-18 membered saturated heterocyclic compound represented by the said general formula (G1) between a pair of counter electrodes, and both positive and negative electrodes between counter electrodes The white display and the black display can be switched reversibly by applying a positive voltage.

[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, particularly preferred are silver and bismuth, and particularly preferred is a silver salt compound.

(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 solution 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 solution is [X] (mol / kg), and the silver or silver contained in the electrolyte solution is a compound that contains silver in the chemical structure. When the total molar concentration of [Metal] (mol / kg) is satisfied, it is preferable that the condition defined by the following formula (1) is satisfied.

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.

[Compound represented by General Formula (G1)]
In the display element of the present invention, a compound (hereinafter, also referred to as a metal salt solvent) for promoting dissolution and precipitation of a metal salt (particularly a silver salt) is represented by the general formula (G1) between the counter electrodes. It has an electrolyte containing a 6-18 membered saturated heterocyclic compound. The compound represented by the general formula (G1) according to the present invention is useful as a silver solvent, has little influence on the coexisting compound, and has a feature of low reactivity with respect to electrical oxidation.

  The compound represented by the general formula (G1) is a saturated heterocyclic compound having 6 to 18 ring members, and all of them are not S.

R ₁ and R ₂ each represent a substituent other than a hydrogen atom or an amino group. Examples of the substituent represented by R ₁ and R ₂ include a substituted or unsubstituted hydrocarbon group, hydroxyl group, alkoxy group, thioether group, halogen compound, carboxylic acid group, carboxylate group, amide group, and sulfinic acid. Groups, sulfonic acid groups, sulfate groups, phosphonic acid groups, phosphate groups, nitro groups, cyano groups and the like.

  n represents an integer of 1 to 3, and m represents an integer of 2 to 9. When m is 2 or more, n may be the same or different.

  In addition, the compound according to the general formula (G1) is desirably less reactive to electrical oxidation than the auxiliary compound. In the present invention, less reactive to electrical oxidation means that the oxidation potential is more noble or is kinetically less reactive to electrical oxidation. It means that fewer compounds are oxidized when a certain voltage is applied between the electrodes.

  Hereinafter, specific examples of the compound represented by the general formula (G1) according to the present invention will be shown, but the present invention is not limited only to these exemplified compounds.

  Among the above-exemplified compounds, Exemplified Compounds G1-3, G1-4, and G1-5 are particularly preferable from the viewpoint that the objective effect of the present invention can be exhibited.

[Auxiliary compound layer]
One feature of the display element of the present invention is that an auxiliary compound layer containing an auxiliary compound that can be oxidized and reduced is disposed in contact with the non-display side electrode to promote an electrochemical reaction.

  The auxiliary compound contained in the auxiliary compound layer according to the present invention may be one in which the optical density in the visible region (400 to 700 nm) does not change or changes, for example, an electrochromic compound as a result of the oxidation-reduction reaction. May be.

  In the auxiliary compound layer according to the present invention, a single auxiliary compound may be used, or a plurality of auxiliary compounds may be used in combination. The auxiliary compound layer containing the auxiliary compound according to the present invention is preferably used by being immobilized on the non-display side electrode.

  The auxiliary compound applicable to the present invention is not particularly limited and may be appropriately selected depending on the purpose. As an auxiliary compound, a known electrochromic compound can be used.

  Examples of preferred auxiliary compounds that can be used in the present invention include the following compound groups.

1) N-oxyl derivatives such as TEMPO (2,2,6,6-tetramethylpiperidinyl-N-oxyl), N-hydroxyphthalimide derivatives, hydroxamic acid derivatives, etc., compounds having an N—O bond ,
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) benzyl (diphenylethanedione) derivative,
5) Tetrazolium salt / formazan derivative,
6) Azine compounds such as phenazine, phenothiazine, phenoxazine, acridine,
7) pyridinium compounds such as viologen,
In addition, benzoquinone derivatives, hydrazyl free radical compounds such as verdazil, thiazyl free radical compounds, hydrazone derivatives, phenylenediamine derivatives, triallylamine derivatives, tetrathiafulvalene derivatives, tetracyanoquinodimethane derivatives, thianthrene derivatives, etc. can also be used as auxiliary compounds. it can.

  In the display device of the present invention, auxiliary compounds in the categories 1) to 7) are preferable, and the N-oxyl derivative described in 1) and the metallocene derivative (ferrocene derivative) described in 3) are particularly preferable.

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

[Electrochromic compound represented by general formula (L)]
In the present invention, it is preferable to use the compound represented by the general formula (L) as the electrochromic compound to perform color display other than black and white in addition to white display and black display by a driving operation of the counter electrode. .

  Hereinafter, the electrochromic compound represented by the general formula (L) according to the present invention will be described.

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

When Rl ₁ represents an aryl group having a substituent, the substituent is not particularly limited, and examples thereof include the following substituents.

  Alkyl groups (eg, methyl, ethyl, propyl, isopropyl, tert-butyl, pentyl, hexyl, etc.), cycloalkyl groups (eg, cyclohexyl, cyclopentyl, etc.), alkenyl groups, cycloalkenyl groups , Alkynyl groups (for example, propargyl group), glycidyl groups, acrylate groups, methacrylate groups, aromatic groups (for example, phenyl group, naphthyl group, anthracenyl group, etc.), heterocyclic groups (for example, pyridyl group, thiazolyl group, oxazolyl group) Group, imidazolyl group, furyl group, pyrrolyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, selenazolyl group, sriphoranyl group, piperidinyl group, pyrazolyl group, tetrazolyl group, etc.), alkoxy group (for example, methoxy group, ethoxy group, propyloxy) Group, pliers Oxy group, cyclopentyloxy group, hexyloxy group, cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, etc.) , Aryloxycarbonyl group (for example, phenyloxycarbonyl group), sulfonamide group (for example, methanesulfonamide group, ethanesulfonamide group, butanesulfonamide group, hexanesulfonamide group, cyclohexanesulfonamide group, benzenesulfonamide group ), Sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylamino) Sulfonyl group, phenylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), urethane group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, phenylureido group, 2-pyridylureido group, etc.), acyl Groups (eg, acetyl, propionyl, butanoyl, hexanoyl, cyclohexanoyl, benzoyl, pyridinoyl, etc.), carbamoyl groups (eg, aminocarbonyl, methylaminocarbonyl, dimethylaminocarbonyl, propylamino) Carbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, phenylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), acylamino group (for example, acetylamino group, benzoyla) Mino group, methylureido group etc.), sulfonyl group (eg methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, phenylsulfonyl group, 2-pyridylsulfonyl group etc.), amino group (eg amino group, Ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, anilino group, 2-pyridylamino group, etc.), halogen atom (eg chlorine atom, bromine atom, iodine atom etc.), cyano group, nitro group, sulfo group Carboxyl group, hydroxyl group, phosphono group (for example, phosphonoethyl group, phosphonopropyl group, phosphonooxyethyl group) and the like. Further, these groups may be further substituted with these groups.

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

Rl _2, Rl is not particularly limited as substituent represented by _3, etc. substituents exemplified as a substituent on the aryl group of the Rl ₁ can be mentioned. Rl ₂ and Rl ₃ are preferably an alkyl group, a cycloalkyl group, an aromatic group, or a heterocyclic group, which may have a substituent. Rl ₂ and Rl ₃ may be linked to each other to form a ring structure. The combination of Rl ₂ and Rl ₃ may be a phenyl group or a heterocyclic group, both of which may have a substituent, or Either one is a phenyl group or a heterocyclic group which may have a substituent, and the other is a combination of an alkyl group which may have a substituent.

X is preferably a> N-Rl _4. Rl ₄ is preferably a hydrogen atom, an alkyl group, an aromatic group, a heterocyclic group or an acyl group, more preferably a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 5 to 10 carbon atoms, or acyl. It is a group.

  In the display element of the present invention, the compound represented by the general formula (L) preferably has an adsorptive group that is chemically or physically adsorbed to the electrode surface. The chemical adsorption referred to in the present invention is a relatively strong adsorption state due to a chemical bond with the electrode surface, and the physical adsorption referred to in the present invention is a relatively strong van der Waals force acting between the electrode surface and the adsorbed substance. It is weakly adsorbed.

In the present invention, the adsorptive group is preferably a chemisorbable group, and as the adsorptive group to be chemisorbed, —COOH, —P═O (OH) ₂ , —OP═O (OH) ₂ and -Si (OR) ₃ (R represents an alkyl group) is preferable.

  Among the azole dyes represented by the general formula (L), an imidazole dye represented by the following general formula (L2) is particularly preferable.

In the general formula (L2), Rl ₂₁ and Rl ₂₂ represent an aliphatic group, an aliphatic oxy group, an acylamino group, a carbamoyl group, an acyl group, a sulfonamide group, and a sulfamoyl group, and Rl ₂₃ represents an aromatic group or an aromatic group. Represents a heterocyclic group, Rl ₂₄ represents a hydrogen atom, an aliphatic group, an aromatic group or an aromatic heterocyclic group, and Rl ₂₅ represents a hydrogen atom, an aliphatic group, an aromatic group or an acyl group.

These groups represented by Rl ₂₁ to Rl ₂₅ may be further substituted with an arbitrary substituent. However, at least one of the groups represented by Rl ₂₁ to Rl ₂₅ has, as its partial structure, —COOH, —P═O (OH) ₂ , —OP═O (OH) ₂ and —Si (OR) ₃ ( R represents an alkyl group.

In the general formula (L2), the group represented by Rl ₂₁ or Rl ₂₂ is preferably an alkyl group (particularly a branched alkyl group), a cycloalkyl group, an alkyloxy group, or a cycloalkyloxy group. Rl ₂₃ is preferably a substituted or unsubstituted phenyl group, a 5-membered or 6-membered heterocyclic group (for example, thienyl group, furyl group, pyrrolyl group, pyridyl group, etc.). Rl ₂₄ is preferably a substituted or unsubstituted phenyl group, a 5-membered or 6-membered heterocyclic group, or an alkyl group. Rl ₂₅ is particularly preferably a hydrogen atom or an aryl group.

In addition, when the compound represented by the general formula (L2) is fixed on the electrode, at least one of the groups represented by Rl _{21 to} Rl ₂₅ includes —P═O (OH) ₂ , —Si as a partial structure. It is preferable to have (OR) ₃ (R represents an alkyl group), and in particular, —Si (OR) ₃ (R represents an alkyl group) as a partial structure of the group represented by Rl ₂₃ or Rl _24. It is preferable to have.

  Specific examples of the EC dye represented by the general formula (L2) and specific examples of the EC dye included in the general formula (L) are shown below, although they do not correspond to the general formula (L2). Is not limited to these exemplified compounds.

[Electrolyte solvent]
If necessary, an electrolyte solvent can be contained in the electrolyte solution. As an electrolyte solvent, it is generally used for electrochemical cells and batteries, and includes various additives such as electrochromic compounds used in the present invention, metal salt compounds that reversibly dissolve and precipitate by an electrochemical redox reaction, promoters, and the like. Any solvent that can be dissolved can be used.

  Specifically, acetic anhydride, methanol, ethanol, tetrahydrofuran, propylene carbonate, nitromethane, acetonitrile, dimethylformamide, dimethyl sulfoxide, hexamethylphosphoamide, ethylene carbonate, dimethoxyethane, γ-butyrolactone, γ-valerolactone, sulfolane, dimethoxy Ethane, propiononitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, dimethylacetamide, methylpyrrolidinone, dimethyl sulfoxide, dioxolane, sulfolane, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, ethyldimethyl phosphate, tributyl phosphate, phosphorus Tripentyl phosphate, trihexyl phosphate, triheptyl phosphate, trioctyl phosphate, trinonyl phosphate, phosphate Ridecyl, tris phosphate (trifluoromethyl), tris phosphate (pentafluoroethyl), triphenyl polyethylene glycol phosphate, polyethylene glycol, 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, and 20 ° C. The salt which consists of an ion pair which is liquid at the temperature over is shown. The room temperature molten salt can be used alone or in combination of two or more.

  The electrolyte solution 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, dimethylsulfoxide, 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 formulas (S1) and (S2))
In the display element of this invention, it is preferable that electrolyte solution contains the compound represented by the following general formula (S1) or (S2).

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

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, These groups 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, 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 represents 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 solution solvent. However, in the display element of the present invention, another compound is used as long as the object effects of the present invention are not impaired. A solvent can be used in combination. 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 in terms of mass average.

  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〕
As the supporting electrolyte that can be used in the display element 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 _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 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.

  In the case of a solid electrolyte, the following compounds exhibiting electronic conductivity and ionic 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. Fluorine-containing compounds such as chalcogenides, CaF ₂ , PbF ₂ , SrF ₂ , LaF ₃ , TlSn ₂ F ₅ , CeF ₃ , Li salts such as Li ₂ SO ₄ , Li ₄ SiO ₄ , Li ₃ PO ₄ , 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 Cu 16 _{7 Cl 13, Rb 3 Cu 7} Cl 10, LiN, compounds such as _{Li 5 NI 2, Li 6 NBr} 3 , and the like.

(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.

  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. .

[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〕
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〕
(Display side transparent electrode)
Of the counter electrodes, the electrode positioned on the display side is preferably a transparent electrode.

  The transparent electrode is not particularly limited as long as it is transparent and conducts electricity. For example, Indium Tin Oxide (ITO: Indium Tin Oxide), Indium Zinc Oxide (IZO: Indium Zinc Oxide), Fluorine Doped Tin Oxide (FTO), Indium Oxide, Zinc Oxide, Platinum, Gold, Silver, Rhodium, Copper, Examples thereof include chromium, carbon, aluminum, silicon, amorphous silicon, and BSO (Bismuth Silicon Oxide).

  In 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 one embodiment of the transparent electrode, a nanoporous electrode having a nanoporous structure can be provided on the transparent 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 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.

(Grid electrode: auxiliary electrode)
An auxiliary electrode can be attached to at least one of the counter 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, a patterning method by photolithography, 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 may be used.

  The line width and line spacing of the auxiliary electrode pattern may be arbitrary values, but the line width needs to be increased 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.

(Method of forming electrode)
A known method can be used to form the transparent electrode and the metal auxiliary electrode. For example, a method of depositing a mask on a substrate by a sputtering method or the like, a method of patterning by a photolithography method after forming the entire surface, and the like can be given.

  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 a coating method, for example, a known method such as a dipping method, a spinner method, a spray method, a roll coater method, a flexographic printing method, a screen printing method, or the like can be used.

  Among the ink jet methods, the following electrostatic ink jet method is capable of continuously printing a highly viscous liquid 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 method>
In the display element of the present invention, at least one of the transparent electrode of the composite electrode and the metal auxiliary electrode has a liquid discharge head having a nozzle with an internal diameter of 30 μm or less for discharging a charged liquid, and supplies a solution into the nozzle. It is one of the preferable embodiments that the liquid discharge device is provided with a supply unit that performs the discharge and a discharge voltage application unit that applies a discharge voltage to the solution in the nozzle. Further, it is preferable that the solution in the nozzle is formed by using a discharge device provided with a convex meniscus forming means for forming a state where the solution rises from the nozzle tip.

  In addition, it comprises operation control means for controlling application of drive voltage for driving the convex meniscus forming means and application of discharge voltage by the discharge voltage application means, and this operation control means applies application of the discharge voltage by the discharge voltage application means. 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.

  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 includes an operation for raising the solution by the convex meniscus forming unit, and application of the discharge voltage. A liquid discharge device having a second discharge control unit that synchronizes the liquid, and the operation control means includes a liquid level 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 in the inside.

  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.

[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.

<< Production of display element >>
(Preparation of electrolyte)
(Preparation of electrolyte 1)
In 2.5 parts by mass of dimethyl sulfoxide, 0.1 part by mass of bismuth chloride, 0.2 part by mass of the exemplified compound (G1-5) and 0.025 part by mass of tetrabutylammonium perchlorate are dissolved to prepare an electrolyte 1. did.

(Preparation of electrolyte 2)
In 2.5 parts by mass of dimethyl sulfoxide, 0.1 part by mass of bismuth chloride, 0.2 part by mass of the exemplary compound (G1-4) and 0.025 part by mass of tetrabutylammonium perchlorate are dissolved to prepare an electrolyte 2. did.

(Preparation of electrolyte 3)
In 2.5 parts by mass of dimethyl sulfoxide, 0.025 parts by mass of spiro- (1,1 ′)-bipyrrolidinium tetrafluoroborate, 0.1 parts by mass of silver p-toluenesulfonate, exemplary compound (G1-4) 0 Electrolyte 3 was prepared by dissolving 2 parts by mass.

(Preparation of electrolytes 4 to 11)
In preparation of the electrolyte 3, instead of the exemplified compound (G1-4), the exemplified compound (G1-3), the exemplified compound (G1-1), the exemplified compound (G1-2), and the exemplified compound (G1-5), respectively. Exemplified compounds (G1-6), Exemplified compound (G1-7), Exemplified compound (G1-8), Exemplified compound (G1-9) were used in the same manner except that the same amount was used to prepare electrolytes 4-11. .

(Preparation of electrolyte 12)
In 2.5 parts by mass of dimethyl sulfoxide, 0.025 part by mass of spiro- (1,1 ′)-bipyrrolidinium tetrafluoroborate, 0.1 part by mass of silver p-toluenesulfonate, The electrolyte 12 was prepared by dissolving part by mass.

(Preparation of electrolyte 13)
In 2.5 parts by mass of dimethyl sulfoxide, 0.025 part by mass of spiro- (1,1 ′)-bipyrrolidinium tetrafluoroborate, 0.1 part by mass of silver p-toluenesulfonate, 0.2 parts by mass of the following compound B The electrolyte 12 was prepared by partially dissolving.

(Preparation of electrolyte 14)
Electrolyte 14 was prepared by dissolving 0.1 part by mass of bismuth chloride, 0.2 part by mass of 2-mercaptobenzimidazole, and 0.025 part by mass of tetrabutylammonium perchlorate in 2.5 parts by mass of dimethyl sulfoxide.

(Preparation of electrolyte 15)
In 2.5 parts by mass of dimethyl sulfoxide, 0.005 parts by mass of Exemplified Compound (L68), 0.025 parts by mass of spiro- (1,1 ′)-bipyrrolidinium tetrafluoroborate, silver p-toluenesulfonate 0.1 The electrolyte 15 was prepared by dissolving 2 parts by mass of 2-massaptobenzimidazole and 2 parts by mass.

(Preparation of electrolyte 16)
In 2.5 parts by mass of dimethyl sulfoxide, 0.005 parts by mass of Exemplified Compound (L68), 0.025 parts by mass of spiro- (1,1 ′)-bipyrrolidinium tetrafluoroborate, carboxy TEMPO (4-carboxy-2, 2,6,6-tetramethylpiperidine-1-oxyl free radical) 0.05 parts by mass, 0.1 parts by mass of silver p-toluenesulfonate, 0.2 parts by mass of the exemplary compound (G1-4) An electrolyte 16 was prepared.

(Preparation of electrolyte 17)
In 2.5 parts by mass of dimethyl sulfoxide, 0.005 part by mass of Exemplified Compound (L1), 0.025 part by mass of spiro- (1,1 ′)-bipyrrolidinium tetrafluoroborate, carboxy TEMPO (4-carboxy-2, 2,6,6-tetramethylpiperidine-1-oxyl free radical) 0.05 parts by mass, 0.1 parts by mass of silver p-toluenesulfonate, 0.2 parts by mass of the exemplary compound (G1-4) An electrolyte 17 was prepared.

(Preparation of electrolyte 18)
In 2.5 parts by mass of dimethyl sulfoxide, 0.025 parts by mass of spiro- (1,1 ′)-bipyrrolidinium tetrafluoroborate and carboxy TEMPO (4-carboxy-2,2,6,6-tetramethylpiperidine-1 -Oxyl free radical) 0.05 mass part, 0.1 mass part of p-toluenesulfonic acid silver, and 0.2 mass part of exemplary compound (G1-4) were melt | dissolved, and the electrolyte 18 was prepared.

[Production of electrodes]
(Production of electrode 1)
An ITO (Indium Tin Oxide) film having a pitch of 145 μm and a width of 130 μm was formed as a conductive layer on a glass substrate having a thickness of 1.5 mm and a size of 2 cm × 4 cm according to a known method. .

(Preparation of electrode 2)
Electrode 1 thoroughly washed with acetone in 1% by mass of ethanol / toluene mixed solution of 3-aminopropyltrimethoxysilane was immersed for 30 minutes and then heated at 150 ° C. for 20 minutes and treated with 3-aminopropyltrimethoxysilane. The obtained electrode 2 was obtained.

(Preparation of electrode 3)
The electrode 2 was placed in a dimethylformamide solution to which 4% by mass of 3-phenothiazin-10-yl-propionic acid and 3% by mass of 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride were added as auxiliary compounds. It was immersed for 30 minutes to form an auxiliary compound layer in which 3-phenothiazin-10-yl-propionic acid, which is an auxiliary compound, was immobilized. On the obtained electrode, the following 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. The electrode 3 was formed by drying for 1 hour to form a porous white scattering layer.

<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 4)
In preparation of the said electrode 3, it replaced with 3-phenothiazin-10-yl-propionic acid as an auxiliary compound, and the electrode 4 was obtained similarly except having used exemplary compound M56.

(Preparation of electrode 5)
In preparation of the said electrode 3, it replaced with 3-phenothiazin-10-yl-propionic acid as an auxiliary compound, and the electrode 5 was obtained similarly except having used exemplary compound M9.

(Preparation of electrode 6)
After applying a paste liquid containing titanium dioxide particles having an average particle diameter of 10 nm on the electrode 1 sufficiently washed with acetone, the solvent of the paste liquid is removed by heating at 150 ° C. for 30 minutes, An electrode 6 on which a nanoporous film of titanium dioxide having a thickness of 1 μm was formed was produced.

(Preparation of electrode 7)
The electrode 6 was immersed in an aqueous solution of 0.5% by mass of 3-aminopropyltrimethoxysilane for 1 hour and then heated at 100 ° C. for 1 hour to obtain an electrode 7 treated with 3-aminopropyltrimethoxysilane.

(Preparation of electrode 8)
The electrode 7 was immersed in a dimethylformamide solution to which 2.5% by mass of the exemplified compound (L1) and 3% by mass of 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride were added for 1 hour to obtain EC. An electrode 8 on which the exemplified compound (L1) as a compound was immobilized was produced.

(Preparation of electrode 9)
On the electrode 1 thoroughly washed with acetone, the titanium dioxide dispersion was screen-printed so that the average film thickness after drying was 20 μm, and then dried at 50 ° C. for 30 minutes to evaporate the solvent. An electrode 9 having a porous white scattering layer formed by drying in an atmosphere at 1 ° C. for 1 hour was produced.

[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 23)
Display elements 2 to 23 were manufactured in the same manner as in the manufacture of the display element 1 except that the electrolyte, the display-side electrode, and the non-display-side electrode were changed to the combinations shown in Table 1.

<< Evaluation of display element >>
[Evaluation of durability]
After connecting both electrodes of each display element manufactured to both terminals of the constant voltage power source and applying a voltage of −1.5 V to the display side electrode for 1.5 seconds, the reflectance of the display portion of each display element is determined by Konica Minolta. Measured with a spectrocolorimeter CM-3700d manufactured by Sensing Co., Ltd., and the reflectance at a wavelength of 550 nm was defined as R ₍₀₎ . Next, a voltage was applied to each display element by repeating 10,000 cycles for 0.5 seconds at +1.5 V and 0.5 seconds at -1.5 V, and then the reflectance was measured in the same manner as described above. The obtained reflectance was defined as R _(10000) .

The change in contrast ratio before and after the repetitive voltage application was defined as ΔR = | R ₍₀₎ −R _(10000) |, and this was used as an index of the stability of the reflectance when this ΔR was repeatedly driven. Here, the smaller the value of ΔR, the better the stability of the reflectance when it is repeatedly driven.

  Table 1 shows the configuration of each display element and the obtained durability evaluation results.

  As is apparent from the results shown in Table 1, the display element having the configuration defined in the present invention has good reflectance stability when driven repeatedly over a long period of time and excellent durability compared to the comparative example. I understand that

Claims (6)

An auxiliary compound layer disposed between the counter electrodes in contact with the non-display side electrode; an electrolyte layer containing a metal salt compound and a 6-18 membered saturated heterocyclic compound represented by the following general formula (G1); And displaying black and white by applying a voltage between the counter electrodes.

[In formula, R < ₁ >, R < ₂ > represents the substituent except a hydrogen atom or an amino group, respectively. n represents an integer of 1 to 3, and m represents an integer of 2 to 9. When m is 2 or more, n may be the same or different. ] The display element according to claim 1, wherein the auxiliary compound layer contains an N-oxyl derivative or a ferrocene derivative. The display element according to claim 1, wherein the metal salt compound is a silver salt compound. A compound represented by the following general formula (L) is contained between the counter electrodes, and color display other than black and white is performed in addition to white display and black display by a driving operation of the counter electrode. The display element according to claim 1.

[Wherein, Rl ₁ represents a substituted or unsubstituted aryl group, and Rl ₂ and Rl ₃ each represent a hydrogen atom or a substituent. X represents> N—Rl ₄ , an oxygen atom or a sulfur atom, and Rl ₄ represents a hydrogen atom or a substituent. ] The compound represented by the said general formula (L) is -COOH, -P = O (OH) ₂ , -OP = O (OH) _2, and -Si (OR) ₃ (R represents an alkyl group.) The display element according to claim 4, wherein the display element has at least one substituent selected from the group consisting of: 6. The display element according to claim 4, wherein the compound represented by the general formula (L) is immobilized on the surface of at least one counter electrode.