JP2010237242A - Display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display element which has simple member structure, which can be driven by low voltage and has excellent reflectance stability in repeat drive. <P>SOLUTION: The display element has an electrolyte layer containing silver salt compound between counter electrodes. The display element has lithium ions between the counter electrodes. One of the counter electrode on a non-observation side has lamination structure of a layer including a metal oxide being active electrochemically and a polymer layer having a lithium ion conductivity. The polymer layer having a lithium ion conductivity is in contact with the electrolyte layer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a display element using a novel electrochemical method.

  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 keep an eye on the browsing means over time, and these actions are hardly human-friendly means. In general, light-emitting displays are known to suffer from eye fatigue due to flickering, inconvenient to carry, limited reading posture, need to focus on a static screen, and increase power consumption 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 that eliminates the drawbacks of each of the above-described methods, an electrodeposition method (hereinafter referred to as an ED method) using dissolution 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-white contrast and black quality, and various methods have been disclosed (for example, Patent Document 1). -3)).

  As a result of examining the techniques disclosed in each of the above patent documents in detail, the present inventor has found that there is a problem in the stability of the reflectance when the conventional technique is repeatedly driven. As one of means for solving the above-mentioned problems, a method for improving the electrolysis driving stability of a metal dissolution precipitation type electrochemical display element has been studied. For example, a redox buffer such as ferrocene is included in the electrolytic solution. The technique to add is disclosed (for example, refer patent document 4).

  The technique described in Patent Document 4 is a technique intended to improve driving stability by redox buffer redoxing at the non-observation side electrode. To improve driving stability, redox buffer is used. It has been found that it is necessary to increase the amount of the buffer added sufficiently, and in that case, the memory performance and the rewriting speed are reduced.

  Patent Document 5 discloses that the durability of the observation-side electrode is reduced by adding a lithium salt compound as a supporting salt to the electrolytic solution to lower the overvoltage of the dissolution and precipitation reaction of the silver salt compound on the observation-side electrode. Attempts have been made to improve the driving stability. However, it has been found that the method described in Patent Document 5 is ineffective with respect to a decrease in driving stability due to a characteristic variation of the non-observation side electrode.

  As another technique, in Patent Document 6, as a technique for improving the driving stability of a display element by electrochromic tungsten oxide, a study using a lithium ion conductive electrolyte as an electrolyte is made. It has been found that there is little effect in terms of improving the driving stability of the display element by the dissolution precipitation reaction.

  Further, in Patent Document 7, studies have been made to improve driving stability by adding lithium ions to the electrolyte and causing oxidation / reduction of lithium ions at the non-observation side electrode. Since the potential is very low, the reduction reaction of lithium ions hardly occurs at an applied voltage in a range where the solvent of the electrolytic solution is not decomposed, and thus it was found that the effect of improving driving stability is small.

U.S. Pat. No. 4,240,716 Japanese Patent No. 3428603 JP 2003-241227 A Special table 2007-508587 gazette JP-A-11-142895 Japanese Patent Laid-Open No. 7-78609 JP2007-72368

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

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

  1. In a display element having an electrolyte layer containing a silver salt compound between the counter electrodes, the counter electrode has a lithium ion between the counter electrodes, and the non-observed electrode of the counter electrode is made of an electrochemically active metal oxide. A display element having a laminated structure of a layer including a polymer layer having lithium ion conductivity, and the polymer layer having lithium ion conductivity being a layer in contact with the electrolyte layer.

  2. 2. The display element according to 1 above, wherein the polymer layer having lithium ion conductivity is formed of at least polyethylene glycol methacrylate.

  3. 3. The display element according to 1 or 2 above, wherein the polymer layer having lithium ion conductivity has a thickness of 50 nm or more and 500 nm or less.

  4). 4. The display element according to any one of 1 to 3, wherein the electrochemically active metal oxide contains tungsten oxide or vanadium oxide.

  According to the present invention, it is possible to provide a display element that has a simple member configuration, can be driven with a low voltage, and has excellent reflectance stability in repeated driving.

  Hereinafter, embodiments 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 has an electrolyte layer containing a silver salt compound between the counter electrodes, and performs display by dissolution and precipitation reaction of the silver salt compound. The counter electrode has lithium ions, and the non-observed electrode of the counter electrode has a laminated structure of a layer containing an electrochemically active metal oxide and a polymer layer having lithium ion conductivity. In addition, by adopting a configuration in which the lithium ion conductive polymer layer becomes a layer in contact with the electrolyte layer, it is possible to drive with a simple member configuration, low voltage, and reflectivity stability in repeated driving. It has been found that an excellent display element can be realized, and has reached the present invention.

  That is, in the present invention, the non-observation side electrode is formed with a laminated structure of a layer made of a metal oxide such as tungsten oxide or vanadium oxide and a lithium ion conductive layer, and the lithium ion conductive layer and the observation side electrode are formed. The electrolyte layer containing a silver salt compound and lithium ions is arranged between the electrodes, and lithium ions move to the layer containing a metal oxide such as tungsten oxide or vanadium oxide on the non-observation side electrode. By making it difficult for silver ions to move, the redox rate of the layer containing a metal oxide such as tungsten oxide or vanadium oxide is sufficiently higher than the rate of dissolution and precipitation of the silver salt compound at the non-observation side electrode. This is a technique for improving driving stability.

  Details of the present invention will be described below.

[Basic structure of display element]
In the display element of the present invention, the display portion is provided with one corresponding counter electrode. For an electrode (also referred to as a display-side electrode or an observation-side electrode) that is one of the counter electrodes close to the observation part, a transparent electrode such as an ITO electrode is used as the other electrode (also referred to as a non-display-side electrode or a non-observation-side electrode). Is provided with a laminated structure of a layer containing an electrochemically active metal oxide according to the present invention and a polymer layer having lithium ion conductivity. Between the observation-side electrode and the non-observation-side electrode, it has an electrolyte layer containing a silver salt compound and lithium ions. By applying positive and negative voltages between the counter electrodes, white display and black display can be achieved. It can be switched reversibly. Lithium ions may be contained in the electrolyte layer at the time of manufacturing the display element or in a polymer layer having lithium ion conductivity.

[Lithium ion conductive polymer layer]
The lithium ion conductive polymer layer according to the present invention is a polymer layer having a lithium ion conductivity of 10 ⁻⁶ S / cm or more at 25 ° C. The lithium ion conductivity can be determined by measuring using an alternating current two-terminal method.

The lithium ion conductivity of the polymer layer having lithium ion conductivity according to the present invention is preferably 10 ⁻⁵ S / cm or more and 10 ⁻² S / cm or less at 25 ° C.

  The film thickness of the polymer layer having lithium ion conductivity according to the present invention is preferably 50 nm or more and 500 nm or less because the rewriting speed is slow if it is too thick and the durability of the polymer film is deteriorated if it is too thin. .

  The polymer for forming the polymer layer having lithium ion conductivity according to the present invention is not particularly limited. For example, polyvinylidene fluoride, polyethylene glycol methacrylate, polyethylene oxide, polyacrylonitrile, polymethyl methacrylate, and ethylene glycol methacrylate Examples include styrene copolymers.

  As a method for forming a polymer layer having lithium ion conductivity according to the present invention, an ink jet method, a spin coating method, a printing method, a spray method, etc. are applied on an electrode using a coating solution in which the polymer according to the present invention is dissolved. It can be formed using a wet coating method.

  Lithium ions may be added in advance to the coating solution to form a polymer layer containing lithium ions. Alternatively, a polymer film may be formed by using a coating solution in which a polymer precursor is dissolved and thermally curing or photocuring the polymer precursor after film formation.

〔lithium ion〕
The lithium ion according to the present invention may be contained in the lithium ion conductive polymer film or may be added as a supporting salt to the electrolyte layer. Lithium ions are an electrolyte for lowering the resistance value of the electrolyte layer, and are desirably selected from substances that do not substantially react on the electrode surface. Further, when the layer containing the electrochemically active metal oxide of the non-observation side electrode is in an oxidized or reduced state, the lithium ion according to the present invention is contained in the film containing the metal oxide. By injecting or pouring, the redox reaction of the metal oxide becomes stable. For example, when the metal oxide is tungsten oxide, when the tungsten oxide is in a reduced state, lithium ions according to the present invention are implanted into the film containing tungsten oxide, and when the tungsten oxide returns to the oxidized state, The lithium ions according to the invention are poured out of the film containing tungsten oxide.

  The amount of lithium ion added according to the present invention is preferably in the range of 1 mmol to 100 mmol per liter of the display element.

  Examples of the lithium ion-based support salt according to the present invention include lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis (trifluoromethylsulfonyl) imide, lithium trifluoromethanesulfonate, and the like.

[Electrochemically active metal oxide]
The electrochemically active metal oxide according to the present invention includes a redox reaction of the metal oxide when a voltage of 2.5 V or less is applied between the counter electrodes, and includes the metal oxide. It is a metal oxide capable of causing the implantation or extraction of lithium ions according to the present invention in the layer.

Electrochemical activity as used in the present invention is defined as that an electrode having a layer containing a metal oxide according to the present invention can take out an electric quantity of 1 mC / cm ² or more when an oxidation-reduction reaction is performed. As an example of a method for measuring the amount of electricity, it can be calculated from a reduction wave or an oxidation wave of a cyclic voltammogram measured by an electrochemical analyzer ALS600C manufactured by ALS. Examples of the electrolytic solution used at the time of measurement include a 0.1 mol / L sulfuric acid aqueous solution and a 0.1 mol / l propylene carbonate solution of lithium tetrafluoroborate. The measurement condition is a scanning speed of 0.05 V / s.

  As an example of the electrochemically active metal oxide according to the present invention, tungsten oxide, niobium oxide, molybdenum oxide, tantalum oxide, and vanadium oxide are preferable, and a more preferable metal oxide is tungsten oxide or vanadium oxide. The thickness of the layer containing the metal oxide according to the present invention is preferably in the range of 0.05 μm or more and 0.8 μm or less.

  The method for forming a layer containing an electrochemically active metal oxide according to the present invention is not particularly limited, and examples thereof include sputtering, vacuum deposition, plasma laser deposition, and electrolytic deposition. Can be mentioned. The sputtering method is preferable from the viewpoint of the strength of the film and the lithium ion implantation or extraction rate according to the present invention, which is preferable as the method for forming the layer containing the electrochemically active metal oxide according to the present invention. The temperature of the substrate during film formation is preferably 120 ° C. or lower. When the temperature of the substrate during film formation is too high, the crystallinity of the film increases, and the lithium ion implantation or extraction rate according to the present invention decreases.

[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] ≦ 0.01
The halogen atom as used in the field of this invention means an iodine atom, a chlorine atom, a bromine atom, and a fluorine atom. When [X] / [Metal] is larger than 0.01, X ⁻ → X ₂ is generated during the metal redox reaction, and X ₂ easily cross-oxidizes with the deposited metal to dissolve the deposited metal. Therefore, the molar concentration of halogen atoms is preferably as low as possible relative to the molar concentration of metallic silver. In the present invention, 0 ≦ [X] / [Metal] ≦ 0.001 is more preferable. In the case of adding halogen ions, the halogen species preferably have a total molar concentration of [I] <[Br] <[Cl] <[F] from the viewpoint of improving memory properties.

[Compound represented by general formula (G-1) or (G-2)]
In the display element of this invention, it is preferable that an electrolyte layer contains the compound represented by the following general formula (G-1) or (G-2).

  The thioether compound represented by the general formula (G-1) and the mercapto compound represented by the general formula (G-2) according to the present invention cause dissolution and precipitation of silver in the present invention. It is a compound that promotes solubilization of silver.

  In general, in order to cause dissolution and precipitation of silver, it is necessary to solubilize silver in the electrolyte. For example, it causes a coordinate bond with silver or a weak covalent bond with silver. Compounds containing chemical structural species that interact with silver are useful. As the chemical structural 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 are useful as silver solvents and It has a feature that it has little influence on coexisting compounds and high solubility in a solvent.

General formula (G-1)
_{Rg 11} -S-Rg ₁₂
In the general formula (G-1), Rg ₁₁ and Rg ₁₂ each represent a substituted or unsubstituted hydrocarbon group. These hydrocarbon groups may contain one or more nitrogen atoms, oxygen atoms, phosphorus atoms, sulfur atoms, and halogen atoms, and Rg ₁₁ and Rg ₁₂ may be linked to each other to form a cyclic structure.

  In the general formula (G-2), M represents a hydrogen atom, a metal atom, or quaternary ammonium. Z represents an atomic group necessary for constituting a nitrogen-containing heterocyclic ring. n represents an integer of 0 to 5, and Rg21 represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkylcarbonamide group, an arylcarbonamide group, an alkylsulfonamide group, an arylsulfonamide group, an alkoxy group, an aryloxy group Group, alkylthio group, arylthio group, alkylcarbamoyl group, arylcarbamoyl group, carbamoyl group, alkylsulfamoyl group, arylsulfamoyl group, sulfamoyl group, cyano group, alkylsulfonyl group, arylsulfonyl group, alkoxycarbonyl group, aryl Represents an oxycarbonyl group, an alkylcarbonyl group, an arylcarbonyl group, an acyloxy group, a carboxyl group, a carbonyl group, a sulfonyl group, an amino group, a hydroxy group or a heterocyclic group, and when n is 2 or more, Rg21 may be the same, or different, may form a condensed ring by combining to each other.

In the general formula (G-1), Rg ₁₁ and Rg ₁₂ each represent a substituted or unsubstituted hydrocarbon group. In these hydrocarbon groups, one or more nitrogen atoms, oxygen atoms, phosphorus atoms, sulfur An atom may be included, and Rg ₁₁ and Rg ₁₂ may be connected to each other to take a cyclic structure.

  Examples of groups that can be substituted for the hydrocarbon group include amino groups, guanidino groups, quaternary ammonium groups, hydroxyl groups, halogen compounds, carboxylic acid groups, carboxylate groups, amide groups, sulfinic acid groups, sulfonic acid groups, and sulfates. Groups, phosphonic acid groups, phosphate groups, nitro groups, cyano groups and the like.

  Specific examples of the compound represented by General Formula (G-1) that can be applied in the present invention are shown below, but the present invention is not limited to these exemplified compounds.

G1-1: CH ₃ SCH ₂ CH ₂ OH
G1-2: HOCH ₂ CH ₂ SCH ₂ CH ₂ OH
G1-3: HOCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ OH
G1-4: HOCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ OH
G1-5: HOCH ₂ CH ₂ SCH ₂ CH ₂ OCH ₂ CH ₂ OCH ₂ CH ₂ SCH ₂ CH ₂ OH
_{G1-6: HOCH 2 CH 2 OCH 2} CH 2 SCH 2 CH 2 SCH 2 CH 2 OCH 2 CH 2 OH
_{G1-7: H 3 CSCH 2 CH 2} COOH
G1-8: HOOCCH ₂ SCH ₂ COOH
G1-9: HOOCCH ₂ CH ₂ SCH ₂ CH ₂ COOH
G1-10: HOOCCH ₂ SCH ₂ CH ₂ SCH ₂ COOH
G1-11: HOOCCH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ COOH
G1-12: HOOCCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH (OH) CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ COOH
G1-13: HOOCCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH (OH) CH (OH) CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ COOH
G1-14: H ₃ CSCH ₂ CH ₂ CH ₂ NH ₂
G1-15: H ₂ NCH ₂ CH ₂ SCH ₂ CH ₂ NH ₂
G1-16: H ₂ NCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ NH _{2
G1-17: H 3 CSCH 2 CH 2} CH (NH 2) COOH
G1-18: H ₂ NCH ₂ CH ₂ OCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ OCH ₂ CH ₂ NH _{2
G1-19: H 2 NCH 2 CH 2} SCH 2 CH 2 OCH 2 CH 2 OCH 2 CH 2 SCH 2 CH 2 NH 2
G1-20: H ₂ NCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ NH ₂
G1-21: HOOC (NH ₂ ) CHCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ CH (NH ₂ ) COOH
G1-22: HOOC (NH ₂ ) CHCH ₂ SCH ₂ CH ₂ OCH ₂ CH ₂ OCH ₂ CH ₂ SCH ₂ CH (NH ₂ ) COOH
G1-23: HOOC (NH ₂ ) CHCH ₂ OCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ OCH ₂ CH (NH ₂ ) COOH
_{G1-24: H 2 N (O =} ) CCH 2 SCH 2 CH 2 OCH 2 CH 2 OCH 2 CH 2 SCH 2 C (= O) NH 2
_{G1-25: H 2 N (O =} ) CCH 2 SCH 2 CH 2 SCH 2 C (= O) NH 2
_{G1-26: H 2 NHN (O =} ) CCH 2 SCH 2 CH 2 SCH 2 C (= O) NHNH 2
_{G1-27: H 3 C (O =} ) CNHCH 2 CH 2 SCH 2 CH 2 SCH 2 CH 2 NHC (= O) CH 3
_{G1-28: H 2 NO 2 SCH 2} CH 2 SCH 2 CH 2 SCH 2 CH 2 SO 2 NH 2
_{G1-29: NaO 3 SCH 2 CH 2} CH 2 SCH 2 CH 2 SCH 2 CH 2 CH 2 SO 3 Na
G1-30: H ₃ CSO ₂ NHCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ NHO ₂ SCH ₃
G1-31: H ₂ N (NH) CSCH ₂ CH ₂ SC (NH) NH ₂ .2HBr
_{G1-32: H 2 N (NH)} CSCH 2 CH 2 OCH 2 CH 2 OCH 2 CH 2 SC (NH) NH 2 · 2HCl
_{G1-33: H 2 N (NH)} CNHCH 2 CH 2 SCH 2 CH 2 SCH 2 CH 2 NHC (NH) NH 2 · 2HBr
G1-34: [(CH ₃ ) ₃ NCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ N (CH ₃ ) ₃ ] 2 ⁺ · 2Cl ⁻

  Of the above-exemplified compounds, Exemplified Compounds G1-2 and G1-3 are particularly preferable from the viewpoint that the object and effects of the present invention can be exhibited.

  Next, the compound represented by formula (G-2) according to the present invention will be described.

  In the general formula (G-2), M represents a hydrogen atom, a metal atom, or quaternary ammonium. Z represents an atomic group necessary for constituting a nitrogen-containing heterocyclic ring. n represents an integer of 0 to 5, and Rg21 represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkylcarbonamide group, an arylcarbonamide group, an alkylsulfonamide group, an arylsulfonamide group, an alkoxy group, an aryloxy group Group, alkylthio group, arylthio group, alkylcarbamoyl group, arylcarbamoyl group, carbamoyl group, alkylsulfamoyl group, arylsulfamoyl group, sulfamoyl group, cyano group, alkylsulfonyl group, arylsulfonyl group, alkoxycarbonyl group, aryl Represents an oxycarbonyl group, an alkylcarbonyl group, an arylcarbonyl group, an acyloxy group, a carboxyl group, a carbonyl group, a sulfonyl group, an amino group, a hydroxy group or a heterocyclic group, and when n is 2 or more, Rg21 may be the same, or different, may form a condensed ring by combining to each other.

In the general formula (G-2), examples of the metal atom represented by M 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 Etc.

  Examples of the nitrogen-containing heterocycle having Z as a constituent in general formula (G-2) 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, Examples include a benzimidazole ring, a benzothiazole ring, a benzoselenazole ring, and a naphthoxazole ring.

In the general formula (G-2), examples of the specific group represented by Rg ₂₁ include a halogen atom (eg, fluorine atom, chlorine atom, bromine atom, iodine atom) alkyl group (eg, methyl, ethyl, propyl). I-propyl, butyl, t-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, dodecyl, hydroxyethyl, methoxyethyl, trifluoromethyl, benzyl, etc.), aryl group (for example, phenyl, naphthyl, etc.), alkylcarboxylic Amido group (eg, acetylamino, propionylamino, butyroylamino, etc.), arylcarbonamide group (eg, benzoylamino, etc.), alkylsulfonamide group (eg, methanesulfonylamino group, ethanesulfonylamino group, etc.), arylsulfone An amide group (eg , Benzenesulfonylamino group, toluenesulfonylamino group etc.), aryloxy group (eg phenoxy etc.), alkylthio group (eg methylthio, ethylthio, butylthio etc.), arylthio group (eg phenylthio group, tolylthio group etc.), alkyl Carbamoyl group (for example, methylcarbamoyl, dimethylcarbamoyl, ethylcarbamoyl, diethylcarbamoyl, dibutylcarbamoyl, piperidylcarbamoyl, morpholylcarbamoyl, etc.), arylcarbamoyl group (for example, phenylcarbamoyl, methylphenylcarbamoyl, ethylphenylcarbamoyl, benzylphenylcarbamoyl, etc.) Alkylsulfamoyl groups (eg methylsulfamoyl, dimethylsulfamoyl, ethylsulfamoyl, diethyl) Sulfamoyl, dibutylsulfamoyl, piperidylsulfamoyl, morpholylsulfamoyl, etc.), arylsulfamoyl groups (eg, phenylsulfamoyl, methylphenylsulfamoyl, ethylphenylsulfamoyl, benzylphenylsulfamoyl) Etc.), alkylsulfonyl groups (eg, methanesulfonyl group, ethanesulfonyl group, etc.), arylsulfonyl groups (eg, phenylsulfonyl, 4-chlorophenylsulfonyl, p-toluenesulfonyl, etc.) alkoxycarbonyl groups (eg, methoxycarbonyl, ethoxycarbonyl, etc.) , Butoxycarbonyl etc.), aryloxycarbonyl group (eg phenoxycarbonyl etc.), alkylcarbonyl group (eg acetyl, propionyl, butyroyl etc.), aryl Rubonyl group (for example, benzoyl group, alkylbenzoyl group, etc.), acyloxy group (for example, acetyloxy, propionyloxy, butyroyloxy, etc.), 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, tetraazaind Lysine ring group). These substituents further include those having a substituent.

  Next, although the preferable specific example of a compound represented by general formula (G-2) is shown, this invention is not limited to these compounds.

  Of the above-exemplified compounds, Exemplified Compounds G2-12, G2-18, and G2-20 are particularly preferable from the viewpoint that the object and effects of the present invention can be exhibited.

〔solvent〕
In the electrolyte according to the present invention, a solvent that is generally used in electrochemical cells and batteries and that can dissolve various additives such as metal salt compounds and promoters that are reversibly dissolved and precipitated by an electrochemical oxidation-reduction reaction. 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 formula (S1) or (S2).

  <Compounds Represented by General Formulas (S1) and (S2)>

In the general formula (S1), L represents an oxygen atom or an alkylene group, and Rs ₁₁ to Rs ₁₄ each represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group, or an alkoxy group.

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

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

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

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

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

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

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

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

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

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

  The compounds represented by the general formulas (S1) and (S2) according to the present invention are one type of electrolyte solvent. However, in the display element of the present invention, another solvent is used as long as the object effects of the present invention are not impaired. Can be used together. Specifically, tetramethylurea, sulfolane, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, 2- (N-methyl) -2-pyrrolidinone, hexamethylphosphortriamide, N-methylpropionamide, N, N-dimethylacetamide, N-methylacetamide, N, N dimethylformamide, N-methylformamide, butyronitrile, propionitrile, acetonitrile, acetylacetone, 4-methyl-2-pentanone, 2-butanol, 1-butanol, 2 -Propanol, 1-propanol, ethanol, methanol, acetic anhydride, ethyl acetate, ethyl propionate, dimethoxyethane, diethoxyfuran, tetrahydrofuran, ethylene glycol, diethylene glycol, triethylene glycol monobuty Ether, water and the like. Among these solvents, it is preferable to include at least one solvent having a freezing point of −20 ° C. or lower and a boiling point of 120 ° C. or higher.

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

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

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

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

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

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

Examples of water-soluble compounds include proteins such as gelatin and gelatin derivatives, 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 (e.g., sodium methacrylate in the vinyl monomer having a methacrylic acid Copolymers with ammonium, 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.

  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.

[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.

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

(Supporting electrolyte)
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.

[Ionic liquid]
The ionic liquid referred to in the present invention is also called a room temperature molten salt, and is a salt having a melting point of 100 ° C. or lower. This salt is composed of the same number of cations and anions, and there are many substances having a melting point below room temperature depending on the molecular structure, and these are in a liquid state at room temperature without adding any solvent. An ionic liquid has a strong characteristic that it has a strong electrostatic interaction and thus has almost no vapor pressure, and does not evaporate even at high temperatures.

  The ionic liquid used in the present invention may be any substance that is generally studied and reported. In particular, an organic ionic liquid has a molecular structure that exhibits a liquid in a wide temperature range including room temperature.

The ionic liquid that can be suitably used in the present invention is represented by the formula Q ⁺ A ⁻ and is 20 to 100 ° C., preferably 20 to 80 ° C., more preferably 20 to 60 ° C., and still more preferably 20 to 40 ° C. In particular, it refers to a salt that exists as a liquid at 20 ° C., and the viscosity (25 ° C.) is not particularly limited as long as it is a melt at normal temperature, but it is preferably 1 to 200 mPa · s. Further, the cation component represented by Q + in the formula is preferably an onium cation, and more preferably an ammonium cation, an imidazolium cation, a pyridinium cation, a sulfonium cation, and a phosphonium cation.

The above-described ionic fluid will be specifically described in detail. As Q ⁺ in the above formula, R ₁ R ₂ R ₃ R ₄ N ⁺ , R ₁ R ₂ R ₃ S ⁺ , R ₁ R ₂ R ₃ R ₄ P ⁺ , R ₁ R ₂ N ⁺ = CR ₃ R ₄ , R ₁ R ₂ P ⁺ = CR ₃ R ₄ [where R ₁ to R ₄ are, independently of one another, hydrogen, saturated or unsaturated carbon C 1 -C 12 alkyl group, a cycloalkyl group having 3 to 8 carbon atoms, an aryl group or an aralkyl group having a carbon number of 7-11 having 6 to 10 carbon _{atoms, R 5 -X- (R 6 -Y-} ) n - (Wherein R ₅ represents an alkyl group having 4 or less carbon atoms, R ₆ represents an alkylene group having 4 or less carbon atoms, X and Y represent an oxygen atom or a sulfur atom, and n represents an integer of 0 to 10). And the group may be substituted] ammonium selected from the group consisting of Phosphonium _{^{ion, R 1 R 2 N + =}} CR 3 -R 7 -R 3 C = N + R 1 R 2, R 1 R 2 S + -R 7 -S + R 1 R 2, R 1 R 2 P + ^{_{= CR 3 -R 7 -R 3 C}} = P + R 1 R 2 ( _wherein, R 1, _{R 2} and _{R 3} are the same as defined above, and _{R 7} is 1 to carbon atoms A quaternary ammonium and / or phosphonium ion selected from the group consisting of 6 alkylene or phenylene groups, which may have a substituent, and nitrogen represented by the following general formula: Examples thereof include nitrogen ions containing 1, 2 or 3 atoms selected from sulfur and phosphorus atoms, ammonium ions derived from sulfur and phosphorus atom-containing heterocycles, sulfonium ions, phosphonium ions, and the like.

Wherein R ₁ and R ₂ are as defined above, and Z is an atom capable of constituting a 4-10 membered ring containing N ⁺ , N ⁺ = C, S ⁺ , P ⁺ or P ⁺ = C And the constituent atoms may have a substituent.

Specific examples of R ₁ to R _{4 in} the above are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, A linear or branched alkyl group such as nonyl and decyl; a cycloalkyl group such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl; unsubstituted or halogen atoms (eg, F, Cl, Br, I ), Hydroxyl group, lower alkoxy group (eg, methoxy, ethoxy, propoxy, butoxy, etc.), carboxyl group, acetyl group, propanoyl group, thiol group, lower alkylthio group (eg, methylthio, ethylthio, propylthio, butylthio, etc.) Each group), amino group, lower alkyl Amino group include phenyl having one to three substituents, such as di-lower alkyl amino group, naphthyl, tolyl, aryl group xylyl, and the like aralkyl groups such as benzyl. Further, specific examples of _{R 5} include methyl, ethyl, n- propyl, isopropyl, n- butyl, isobutyl, sec- butyl, and alkyl group such as tert- butyl group, methylene as _{R 6} And alkylene groups such as ethylene, propylene and butylene groups. Furthermore, specific examples of R ₇ include alkylene groups such as methylene, ethylene, propylene, and butylene, and phenylene groups such as phenylene.

Further, A in the formula ^- Examples of the counter anion represented by, hexafluorophosphate, hexafluoroantimonate, hexafluoroarsenate, fluorosulfonate salts, tetrafluoroborate, nitrate, alkyl sulfonate Represents a fluorinated alkyl sulfonate or a hydrogen sulfate.

  Furthermore, WO95 / 18456, JP-A-8-259543, JP-A-2001-243959, Electrochemical Vol.65, No.11, p.923 (1997), EP-716288, J. Org. Electrochem. Soc. , Vol. 143, no. 10, 3099 (1996), Inorg. Chem. The pyridinium salts, imidazolium salts, triazolium salts and the like described in 1996, 35, 1168 to 1178 can be selected and used in a timely manner according to the present invention.

[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.

(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.

[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).

  Table 1 below shows the types of compounds and the locations described in these three research disclosures.

  The above additives may be provided in auxiliary layers such as a protective layer, a filter layer, an antihalation layer, a crossover light cut layer, and a backing layer, and may be contained in these auxiliary layers.

〔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, patterning may be performed by photolithography, followed by printing, ink-jet printing, electrolytic plating or electroless plating, and exposure and development using a silver salt photosensitive material to form a pattern.

  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 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.

[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.

<< Preparation of electrolyte >>
(Preparation of electrolyte 1)
In 2.5 g of dimethyl sulfoxide (DMSO), 0.1 g of silver iodide, 0.1 g of sodium iodide and 0.025 g of tetrabutylammonium perchlorate were dissolved to obtain an electrolytic solution 1.

(Preparation of electrolyte 2)
In 2.5 g of dimethyl sulfoxide (DMSO), 0.1 g of silver iodide, 0.1 g of sodium iodide, and 0.025 g of bis (trifluoromethylsulfonyl) imidolithium (Li-1) are dissolved. 2 was obtained.

(Preparation of electrolyte 3)
In 2.5 g of N-methylpyrrolidone (NMP), 0.1 g of silver iodide, 0.1 g of sodium iodide, 0.025 g of bis (trifluoromethylsulfonyl) imidolithium (Li-1), and polyvinylidene fluoride (PVDF) ) 1.0 g was dissolved to obtain an electrolytic solution 3.

(Preparation of electrolyte 4)
In 2.5 g of N-methylpyrrolidone (NMP), 0.1 g of silver p-toluenesulfonate, 0.2 g of the exemplified compound (G2-12), lithium bis (trifluoromethylsulfonyl) imidolithium (Li-1), 0. 025 g and 1.0 g of polyvinylidene fluoride (PVDF) were dissolved to obtain an electrolytic solution 4.

(Preparation of electrolyte 5)
In 2.5 g of the exemplary compound (S1-4), 0.1 g of silver p-toluenesulfonate and 0.2 g of the exemplary compound (G2-12) were dissolved to obtain an electrolytic solution 5.

(Preparation of electrolyte 6)
In 2.5 g of the exemplified compound (S1-4), 0.1 g of silver p-toluenesulfonate, 0.2 g of the exemplified compound (G2-12), bis (trifluoromethylsulfonyl) imidolithium (Li-1),. 025 g was dissolved to obtain an electrolytic solution 6.

(Preparation of electrolyte solution 7)
In 2.5 g of exemplary compound (S1-4), 0.1 g of silver p-toluenesulfonate, 0.2 g of exemplary compound (G2-12) and 0.025 g of lithium tetrafluoroborate (Li-2) It was made to melt | dissolve and the electrolyte solution 7 was obtained.

(Preparation of electrolyte 8)
In 2.5 g of the exemplified compound (S1-4), 0.1 g of silver p-toluenesulfonate, 0.2 g of the exemplified compound (G2-12) and 0.025 g of lithium trifluoromethanesulfonate (Li-3) are dissolved. Thus, an electrolytic solution 8 was obtained.

(Preparation of electrolyte 9)
In 2.5 g of the exemplary compound (S1-4), 0.1 g of silver p-toluenesulfonate and 0.2 g of the exemplary compound (G1-3) were dissolved to obtain an electrolytic solution 9.

<Production of electrode>
(Production of electrode 1)
An ITO (Indium Tin Oxide) film was formed on a 2 cm × 4 cm glass substrate having a thickness of 1.5 mm according to a known method to obtain a transparent electrode (electrode 1).

(Preparation of electrode 2)
A solution obtained by dissolving polyvinylidene fluoride (PVDF) in N-methylpyrrolidone so as to be 2.5% by mass and bis (trifluoromethylsulfonyl) imidolithium (Li-1) in 0.13% by mass was used as an electrode 1 A polymer layer composed of polyvinylidene fluoride (PVDF) containing bis (trifluoromethylsulfonyl) imidolithium (Li-1) is formed on the film by spin coating so that the average film thickness is 100 nm. Thus, an electrode 2 was produced.

(Preparation of electrode 3)
An ITO-tungsten oxide electrode was fabricated on the electrode 1 by sputtering to form a tungsten oxide film having an average film thickness of 200 nm.

  Next, a solution obtained by dissolving polyvinylidene fluoride (PVDF) in N-methylpyrrolidone so as to be 2.5 mass% and bis (trifluoromethylsulfonyl) imidolithium (Li-1) to be 0.13% by mass, It is made of polyvinylidene fluoride (PVDF) containing bis (trifluoromethylsulfonyl) imidolithium (Li-1) coated on the ITO-tungsten oxide electrode by spin coating so that the average film thickness is 100 nm. The electrode 3 was produced by forming a polymer layer.

(Preparation of electrode 4)
A solution prepared by dissolving polyethylene glycol methacrylate (PEGMA) in N-methylpyrrolidone so as to be 2.5% by mass and bis (trifluoromethylsulfonyl) imidolithium (Li-1) to be 0.13% by mass was used as an electrode 3. A polyethylene glycol methacrylate (PEGMA) containing bis (trifluoromethylsulfonyl) imidolithium (Li-1) was applied on the ITO-tungsten oxide electrode used in the preparation of the above by spin coating so that the average film thickness was 30 nm. ) Was formed to produce an electrode 4.

(Preparation of electrode 5)
A solution prepared by dissolving polyethylene glycol methacrylate (PEGMA) in N-methylpyrrolidone so as to be 2.5% by mass and bis (trifluoromethylsulfonyl) imidolithium (Li-1) to be 0.13% by mass was used as an electrode 3. Polyethylene glycol methacrylate containing bis (trifluoromethylsulfonyl) imidolithium (Li-1) coated on the ITO-tungsten oxide electrode used in the production of bis (trifluoromethylsulfonyl) imide lithium (Li-1) by spin coating. A polymer layer composed of (PEGMA) was formed to produce the electrode 5.

(Preparation of electrode 6)
A solution prepared by dissolving polyethylene glycol methacrylate (PEGMA) in N-methylpyrrolidone so as to be 2.5% by mass and bis (trifluoromethylsulfonyl) imidolithium (Li-1) to be 0.13% by mass was used as an electrode 3. The polyethylene glycol methacrylate containing bis (trifluoromethylsulfonyl) imidolithium (Li-1) was coated on the ITO-tungsten oxide electrode used in the preparation of the above by spin coating so that the average film thickness was 100 nm. A polymer layer composed of (PEGMA) was formed to produce an electrode 6.

(Preparation of electrode 7)
A solution prepared by dissolving polyethylene glycol methacrylate (PEGMA) in N-methylpyrrolidone so as to be 2.5% by mass and bis (trifluoromethylsulfonyl) imidolithium (Li-1) to be 0.13% by mass was used as an electrode 3. A polyethylene glycol methacrylate containing bis (trifluoromethylsulfonyl) imidolithium (Li-1) was applied on the ITO-tungsten oxide electrode used in the preparation of the above by spin coating so that the average film thickness was 500 nm. A polymer layer composed of PEGMA) was formed to produce an electrode 7.

(Preparation of electrode 8)
A solution prepared by dissolving polyethylene glycol methacrylate (PEGMA) in N-methylpyrrolidone so as to be 2.5% by mass and bis (trifluoromethylsulfonyl) imidolithium (Li-1) to be 0.13% by mass was used as an electrode 3. It consists of polyethylene glycol methacrylate (PEGMA) containing bis (trifluoromethylsulfonyl) imidolithium (Li-1) on the ITO-tungsten oxide electrode used in the production of bis (trifluoromethylsulfonyl) imidolithium (Li-1) so as to have an average film thickness of 800 nm by spin coating. A polymer layer was formed to produce an electrode 8.

(Preparation of electrode 9)
The copolymer of ethylene glycol methacrylate and styrene (P-1) is 2.5% by mass, and bis (trifluoromethylsulfonyl) imidolithium (Li-1) is 0.13% by mass in N-methylpyrrolidone. Using the solution dissolved in the solution, it was applied on the ITO-tungsten oxide electrode used in the production of the electrode 3 by spin coating so that the average film thickness became 30 nm, and bis (trifluoromethylsulfonyl) imide lithium (Li Electrode 9 was produced by forming a polymer layer composed of a copolymer (P-1) of ethylene glycol methacrylate and styrene containing -1).

(Production of electrode 10)
A solution prepared by dissolving polyethylene oxide (PEO) in N-methylpyrrolidone so as to be 2.5% by mass and bis (trifluoromethylsulfonyl) imidolithium (Li-1) to be 0.13% by mass Polyethylene oxide (PEO) containing bis (trifluoromethylsulfonyl) imidolithium (Li-1) was applied on the ITO-tungsten oxide electrode used in the production by spin coating so that the average film thickness was 30 nm. The electrode 10 was produced by forming a polymer layer composed of

(Preparation of electrode 11)
In the preparation of the electrode 3, a solution in which polyethylene glycol methacrylate (PEGMA) is 2.5% by mass and lithium tetrafluoroborate (Li-2) is 0.13% by mass in N-methylpyrrolidone is prepared. A polymer composed of polyethylene glycol methacrylate (PEGMA) containing lithium tetrafluoroborate (Li-2) coated on the ITO-tungsten oxide electrode by spin coating so as to have an average film thickness of 100 nm. A layer was formed to produce an electrode 11.

(Preparation of electrode 12)
A solution in which polyethylene glycol methacrylate (PEGMA) is 2.5% by mass and lithium trifluoromethanesulfonate (Li-3) is 0.13% by mass in N-methylpyrrolidone is used in the production of electrode 3. A polymer layer made of polyethylene glycol methacrylate (PEGMA) containing lithium trifluoromethanesulfonate (Li-3), coated on an ITO-tungsten oxide electrode by spin coating so as to have an average film thickness of 100 nm. Was formed into an electrode 12.

(Preparation of electrode 13)
A vanadium oxide film was formed on the electrode 1 by a sputtering method so as to have an average film thickness of 200 nm to produce an ITO-vanadium oxide electrode.

  Next, a solution obtained by dissolving polyethylene glycol methacrylate (PEGMA) in N-methylpyrrolidone so as to be 2.5% by mass and bis (trifluoromethylsulfonyl) imide lithium (Li-1) to be 0.13% by mass, It is coated on the ITO-vanadium oxide electrode by spin coating so that the average film thickness is 100 nm, and is composed of polyethylene glycol methacrylate (PEGMA) containing bis (trifluoromethylsulfonyl) imidolithium (Li-1). The electrode 13 was produced by forming a polymer layer.

(Preparation of electrode 14)
On the electrode 1, a nickel oxide film was formed by sputtering to have an average film thickness of 200 nm to produce an ITO-nickel oxide electrode.

  A solution prepared by dissolving polyethylene glycol methacrylate (PEGMA) in N-methylpyrrolidone so as to be 2.5% by mass and bis (trifluoromethylsulfonyl) imidolithium (Li-1) in 0.13% by mass was used as the ITO. -It is made of polyethylene glycol methacrylate (PEGMA) containing bis (trifluoromethylsulfonyl) imidolithium (Li-1) coated on a nickel oxide electrode by spin coating so that the average film thickness becomes 100 nm. A polymer layer was formed to produce an electrode 14.

(Preparation of electrode 15)
A gold film was formed on the electrode 1 by a sputtering method so as to have an average film thickness of 50 nm to produce an ITO-gold electrode.

  Next, a solution in which polyethylene glycol methacrylate (PEGMA) is 2.5% by mass and bis (trifluoromethylsulfonyl) imidolithium (Li-1) is 0.13% by mass in N-methylpyrrolidone, A polymer composed of polyethylene glycol methacrylate (PEGMA) containing bis (trifluoromethylsulfonyl) imidolithium (Li-1) coated on an ITO-gold electrode by spin coating so as to have an average film thickness of 100 nm. A layer was formed to produce an electrode 15.

(Preparation of electrode 16)
A solution obtained by dissolving polyethylene glycol methacrylate (PEGMA) in N-methylpyrrolidone so as to be 2.5% by mass is formed on the ITO-tungsten oxide electrode used in the production of the electrode 3 by spin coating so as to have an average film thickness. The electrode 16 was produced by coating the film so as to be 100 nm and forming a polymer layer composed only of polyethylene glycol methacrylate (PEGMA).

(Measurement of lithium ion conductivity of polymer layer)
About the produced electrodes 2-16, the measurement of lithium ion conductivity at 25 degreeC was performed using the alternating current two-terminal method, and the obtained result is shown in Table 2.

  In addition, the detail of each additive described by the abbreviation in Table 2 mentioned later is as follows.

(Non-observation side electrode)
<Electrode material>
ITO: Indium Tin Oxide, Indium Tin Oxide <Polymer layer constituent material>
PVDF: Polyvinylidene fluoride PEGMA: Polyethylene glycol methacrylate P-1: Copolymer of ethylene glycol methacrylate and styrene PEO: Polyethylene oxide <Lithium compound>
Li-1: bis (trifluoromethylsulfonyl) imidolithium Li-2: lithium tetrafluoroborate Li-3: lithium trifluoromethanesulfonate (electrolyte layer)
<Silver salt compound>
Silver tosylate: silver p-toluenesulfonate <solvent>
DMSO: Dimethyl sulfoxide << Preparation of display element >>
(Preparation of display element 1)
On the electrode 1, the following 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. The electrode 1a which formed the porous white scattering layer by drying for hours was produced. Next, the periphery of the electrode 1a is bordered with an olefin-based sealant containing glass spherical beads having an average particle diameter of 40 μm as a volume fraction of 10%, and then the electrode 1a having a porous white scattering layer and the porous The cells 1 were bonded so as to be orthogonal to the electrode 1 on which the white scattering layer was not formed, 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.

<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.

(Production of display elements 2, 4, 6 to 24)
Display elements 2, 4, and 6 to 24 were produced in the same manner as the display element 1 except that the types of the electrolytic solution and the electrode were changed to the combinations shown in Table 2.

(Preparation of display element 3)
On the electrode 1, the titanium dioxide dispersion was screen-printed so that the average film thickness after drying was 20 μm, then dried at 50 ° C. for 30 minutes to evaporate the solvent, and then 1 in an atmosphere at 85 ° C. It was dried for a time to form a porous white scattering layer. Subsequently, the electrolytic solution 3 was screen-printed on the porous white scattering layer so that the average film thickness after drying was 20 μm, then dried at 200 ° C. for 30 minutes to evaporate the solvent, and then the atmosphere at 85 ° C. The electrode 1b in which the electrolyte layer having the electrolytic solution 3 was formed by drying for 1 hour was produced. Next, the periphery of the electrode 1b is bordered with an olefin-based sealant containing 10% glass spherical beads having an average particle diameter of 40 μm as a volume fraction, and then an electrode 1b on which a porous white scattering layer and an electrolyte layer are formed The porous white scattering layer and the electrode 1 on which the electrolyte layer is not formed are bonded so as to be orthogonal to each other and further heated and pressed to produce a display element 3.

(Preparation of display element 5)
A display element 5 was produced in the same manner as the display element 3 except that the types of the electrolytic solution and the electrode were changed to the combinations shown in Table 2.

<< Evaluation of display element >>
[Evaluation of reflectance stability when driven repeatedly]
When both electrodes of the display element are connected to both terminals of the constant voltage power source, a voltage of +1.5 V is applied for 1 second, and then a voltage of -1.5 V is applied for 0.5 second to display gray The reflectance at a wavelength of 550 nm was measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing. Under the same driving conditions, driving was performed 10 times in total, and the average value of the obtained reflectances was defined as R _ave1 . Further, after driving repeatedly 10,000 times, R _ave2 was obtained by the same method. ΔR _BK1 = | R _{ave1 −Rave2} | was used as an index of stability of reflectance when ΔR _BK1 was repeatedly driven. Here, the smaller the value of ΔR _BK1, the better the stability of the reflectance when driven repeatedly.

  As is apparent from the results shown in Table 2, it can be seen that the display element satisfying the configuration of the present invention has improved reflectance stability when it is repeatedly driven as compared with the comparative example.

Claims (4)

  In a display element having an electrolyte layer containing a silver salt compound between the counter electrodes, the counter electrode has a lithium ion between the counter electrodes, and the non-observed electrode of the counter electrode is made of an electrochemically active metal oxide. A display element having a laminated structure of a layer including a polymer layer having lithium ion conductivity, and the polymer layer having lithium ion conductivity being a layer in contact with the electrolyte layer.   The display element according to claim 1, wherein the polymer layer having lithium ion conductivity is formed of at least polyethylene glycol methacrylate.   The display element according to claim 1, wherein a film thickness of the polymer layer having lithium ion conductivity is 50 nm or more and 500 nm or less.   The display element according to claim 1, wherein the electrochemically active metal oxide contains tungsten oxide or vanadium oxide.