JP2009198770A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device with a simple configuration which can be driven by a low voltage, and is high in display contrast and in white display reflectance, and which hardly causes fluctuation in reflectance in repeated driving. <P>SOLUTION: The display device contains at least one electrochromic dyes which are reversibly colored or decolored by at least either of electrochemical oxidation reaction and reduction reaction, electrolyte, and white dispersion material, and performs color tone change by a driving operation of counter electrodes between the counter electrodes. In the display device, the electrochromic dyes are fixed onto the electrode surfaces and the element has a compound having a Verdazyl structure between the counter electrodes. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a novel electrochemical display element capable of multicolor display with a single layer structure.

  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 that have been conventionally provided on printed matter on paper has become easier to electronic information. Opportunities to obtain and browse electronic information as it is gaining more and more are increasing.

  As such electronic information browsing means, conventional liquid crystal displays and CRTs, and in recent years, light-emitting types such as organic EL displays are mainly used. Particularly, when electronic information is document information, it is relatively long time. It is necessary to pay close attention to this browsing means, and these actions are not necessarily human-friendly means. 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 that uses external light and does not consume power for image retention (memory type) is known, but has sufficient performance for the following reasons. It's hard to say.

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

  As a display method for solving the disadvantages of each of the above-mentioned methods, there are an electrochromic display element (hereinafter abbreviated as EC method) and an electrodeposition method (hereinafter abbreviated as ED method) using dissolution precipitation of metal or metal salt. Are known. The EC method has the advantage of being capable of full-color display at a low voltage of 3V or less, a simple cell configuration, and excellent white quality. The ED method can also be driven at a low voltage of 3V or less and is a simple cell. There are advantages such as excellent configuration, black-white contrast and black quality, and various methods have been disclosed (for example, see Patent Documents 1 to 6).

  As a result of a detailed examination of the techniques disclosed in the above-mentioned patent documents, it has been found that these methods have a problem in the stability of reflectance when repeatedly driven. As a means for solving this, a method of adding a ferrocene compound as a redox buffer to the electrolyte as described in Patent Document 7, or a redox promoter as described in Patent Document 8 on the electrode. Although there is a method of immobilization, further improvement is necessary to meet the recent increase in user requirements.

The present inventor has found that the verdazyl compound according to the present invention is effective in satisfying these requirements. Patent Document 9 describes an electrochromic display device using a veldazyl compound, but the veldazyl compound is used as an EC dye that oxidizes and develops color in the patent document. When a verdazyl compound was used as an EC dye, the color tone was limited and the stability of the dye itself was poor, and the performance was insufficient as a dye for display elements. Patent Document 9 describes an example in which a veldazyl compound that produces oxidative color and an EC dye that produces reduction color is described. However, when applied to either positive or negative color, it becomes a colored state, and multi-color display is achieved with a single layer configuration. Cannot be made possible. Further, it is not suggested that the effect of stabilizing the reflectance when repeatedly driven is obtained.
International Publication No. 04/068231 Pamphlet International Publication No. 04/066733 Pamphlet U.S. Pat. No. 4,240,716 Japanese Patent No. 3428603 JP 2003-241227 A Special table 2007-508587 gazette Special table 2007-508587 gazette US Pat. No. 7,253,940 JP 58-23878 A

  The present invention has been made in view of the above problems, and its object is a display element that can be driven with a simple member configuration, low voltage, high display contrast, and high white display reflectance, and can be driven repeatedly. An object of the present invention is to provide a display element with little variation in reflectance.

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

  1. Between the counter electrodes, containing at least one electrochromic dye, an electrolyte, and a white scatterer that reversibly develop or decolorize by at least one of an electrochemical oxidation reaction and a reduction reaction, and by driving the counter electrode, A display element that changes color tone, wherein the electrochromic dye is immobilized on an electrode surface, and the display element has a compound having a veldazil structure between opposing electrodes.

  2. 2. The display element according to 1 above, wherein the compound having a verdazyl structure is represented by the following general formula (V).

(Wherein Rv _{1 to} Rv ₃ each represents an aromatic group, an aliphatic group or a heterocyclic group which may have a substituent, X represents a methylene group which may have a substituent,> C═O ,> C = S,> C = N—R, where R represents a hydrogen atom or a substituent.)
3. 3. The display element according to 1 or 2, wherein the electrochromic dye is colored by an oxidation reaction.

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

(In the formula, Rl ₁ represents a substituted or unsubstituted aryl group, 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. Any one of the above 1 to 4, wherein a metal salt compound is contained between the counter electrodes, and multi-color display of three or more colors of black display, white display, and color display other than black is performed by driving the counter electrode. Item 1. A display element according to item 1.

  6). 6. The display device as described in 5 above, wherein the metal salt compound is a silver salt compound.

  According to the present invention, a novel electrochemical display element capable of realizing bright white display, high-contrast black-and-white display and full-color display with a simple member configuration can be provided.

  Details of the present invention will be described below.

<< Basic configuration of display element >>
In the display element of the present invention, the display portion is provided with one corresponding counter electrode. The electrode 1 which is one of the counter electrodes close to the display unit is provided with a transparent electrode such as an ITO electrode, and the other electrode 2 is provided with a conductive electrode.

  At least one type of electrochromic dye, electrolyte, white scatterer, and veldazil that are reversibly developed or decolored by at least one of an electrochemical oxidation reaction and a reduction reaction according to the present invention between the electrode 1 and the electrode 2 Contains a compound having a structure.

  In the present invention, the electrochromic dye is immobilized on the electrode, and a preferred form is that it is immobilized on the surface of the electrode 1. Moreover, although the compound which has a veldazil structure may be contained in electrolyte, a preferable form is that it is fix | immobilized on the electrode surface.

  In a more preferred embodiment of the present invention, a metal salt compound is contained between the counter electrodes.

  In the display element of the present invention, by applying a voltage of positive and negative polarity between the counter electrodes, coloring / decoloring reaction due to oxidation / reduction of electrochromic dye or dissolution / precipitation reaction of metal is performed, black, white, A colored state other than black can be switched reversibly.

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

(Counter electrode)
In the display element of the present invention, the electrode that is not on the display portion side is preferably a metal electrode. As the metal electrode, for example, known metal species such as platinum, gold, silver, copper, aluminum, zinc, nickel, titanium, bismuth, and alloys thereof can be used. The metal electrode is preferably a metal of a metal salt compound in the electrolyte, for example, a metal having a work function close to the redox potential of silver. Among them, silver or a silver electrode having a silver content of 80% or more is used for maintaining the reduced state of silver. It is also advantageous in preventing electrode contamination. As an electrode manufacturing method, an existing method such as an evaporation method, a printing method, an ink jet method, a spin coating method, or a CVD method can be used.

<Semiconductor nanoporous layer>
A semiconductor nanoporous layer can be formed on the transparent electrode on the display unit side in order to immobilize a dye or the like. In order to increase the surface area, the semiconductor nanoporous layer has micropores capable of supporting an EC dye or the like on the surface and inside thereof. The specific surface area of the semiconductor nano-porous layer is preferably from ^{1~5000m 2 / g, 10~2500m 2 /} g is more preferable. Here, the specific surface area means the BET specific surface area obtained from the adsorption amount of nitrogen gas. If the specific surface area is too small, the adsorption amount of the EC dye cannot be increased, and the object of the present invention may not be achieved.

  The semiconductor fine particles contained in the semiconductor nanoporous layer are not particularly limited and may be appropriately selected according to the purpose. For example, a single semiconductor, an oxide semiconductor, a compound semiconductor, an organic semiconductor, a composite oxide semiconductor Or a mixture thereof, which may contain impurities as a dopant. There is no particular limitation on the form of the semiconductor, and it may be single crystal, polycrystalline, amorphous, or a mixed form thereof.

The semiconductor fine particles are preferably oxide semiconductors. An oxide semiconductor is a metal oxide and has semiconductor properties. For example, TiO ₂ , SnO ₂ , Fe ₂ O ₃ , SrTiO ₃ , WO ₃ , ZnO, ZrO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , V ₂ O ₅ , In ₂ O ₃ , CdO, MnO, CoO, TiSrO ₃ , KTiO ₃ , Cu ₂ O, sodium titanate, barium titanate, potassium niobate and the like.

  The shape of the semiconductor fine particles is not particularly limited and can be appropriately selected according to the purpose. The shape may be any of a spherical shape, a nanotube shape, a rod shape, and a whisker shape, and two or more types having different shapes may be used. Fine particles can also be mixed. In the case of the spherical particles, the average particle size is preferably 0.1 to 1000 nm, and more preferably 1 to 100 nm. Two or more kinds of fine particles having different particle size distributions may be mixed. In the case of the rod-like particles, the aspect ratio is preferably 2 to 50000, and more preferably 5 to 25000.

《Electrochromic dye (EC dye)》
The EC dye used in the present invention is not particularly limited as long as it exhibits an action of color development or decoloration by at least one of an electrochemical oxidation reaction and a reduction reaction, and can be appropriately selected according to the purpose. Examples of EC dyes include metal complexes, conductive polymer compounds, and organic dyes.

  Examples of metal complexes exhibiting EC characteristics include Prussian blue, metal-bipyridyl complexes, metal phenanthroline complexes, metal-phthalocyanine complexes, ferrocene dyes, phthalocyanine dye derivatives thereof, and the like.

  Examples of the conductive polymer compound exhibiting EC characteristics include polypyrrole, polythiophene, polyisothianaphthene, polyaniline, polyphenylenediamine, polyaminophenol, polyvinylcarbazole, polycarbazole, and derivatives thereof.

  Examples of organic dyes exhibiting EC characteristics include pyridine compounds, phenothiazine dyes, styryl dyes, anthraquinone dyes, pyrazoline dyes, and fluorane dyes. Examples of the pyridine compound include viologen, heptyl viologen, methylene bispyridinium, phenanthroline, azobipyridinium, quinoline, and isoquinoline. In addition, JP2007-171781A, 2007-219271, 2007-219272, 2007-279659, 2007-279570, 2007-279571, 2007-279572. Examples include compounds described in the publication.

  Examples of the EC dye include a reduction coloring type that exhibits colorless to ultra-light color in the oxidation state and develops color in the reduction state, an oxidation coloring type that exhibits colorless to ultra-light color in the reduction state and develops color in the oxidation state, and a reduction state However, it may be any of the multicolor coloring types that exhibit color development in the oxidized state and develop several kinds of colors depending on the degree of reduction or oxidation, and can be appropriately selected according to the purpose, but the oxidation coloring type is preferred. In particular, imidazole dyes are preferred.

(Compound represented by formula (L))
In the present invention, the most preferable dye as the EC dye is a compound represented by the general formula (L). 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), 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, and more preferably a substituted or unsubstituted 2-hydroxyphenyl group or 4-hydroxyphenyl group.

The substituent represented by R1 ₂ or Rl ₃ is not particularly limited, and examples thereof include the substituents exemplified as the substituent on the aryl group of Rl ₁ . 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. As a combination of Rl ₂ and Rl ₃ , when both are phenyl groups which may have a substituent, either one is a phenyl group which may have a substituent, and the other has a substituent. It is a combination of alkyl groups that may be used.

X is preferably> 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 or acyl having 5 to 10 carbon atoms. It is a group.

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

(Adsorbable group)
In the display element of the present invention, it is preferable that the compound represented by the general formula (L) according to the present invention has an adsorptive group that is chemically or physically adsorbed on the electrode surface.

  The chemical adsorption according to the present invention is a relatively strong adsorption state due to a chemical bond with the electrode surface, and the physical adsorption according to the present invention is a relatively strong van der Waals force acting between the electrode surface and the adsorbed substance. It is weakly adsorbed.

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

<< Compound with Verdazyl Structure >>
One feature of the display element of the present invention is that it includes a compound having a veldazil structure between counter electrodes.

  A nitrogen-containing cyclic free radical of the 1,2,4,5-tetraaza-5-cyclohexenyl type is generally referred to as veldazyl (or ferdadil). The compound having a verdazyl structure according to the present invention means a compound having a nitrogen-containing cyclic free radical structure of 1,2,4,5-tetraaza-5-cyclohexenyl type as a part of the molecular structure. Depending on the case, it may have a substituent. Further, it may be a multimer having a plurality of veldazyl structures in the molecule or a polymer.

  In the present invention, the compound having a verdazyl structure is preferably a compound represented by the general formula (V).

In the general formula (V), Rv _{1 to} Rv ₃ each represents an aromatic group, an aliphatic group, or a heterocyclic group which may have a substituent. Examples of the aromatic group include a phenyl group, a naphthyl group, and an anthracenyl group. Examples of the aliphatic group include an alkyl group (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, etc.), cycloalkyl group (for example, cyclohexyl group, cyclopentyl group, etc.), An alkenyl group, a cycloalkenyl group, an alkynyl group (for example, a propargyl group etc.) is mentioned. Examples of the heterocyclic group include pyridyl group, thiazolyl group, oxazolyl group, imidazolyl group, furyl group, pyrrolyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, selenazolyl group, sriphoranyl group, piperidinyl group, pyrazolyl group, and tetrazolyl group. Etc.

Rv ₁ is preferably a phenyl group which may have a substituent, or a 5-membered or 6-membered heteroaromatic ring group. Rv ₂ and Rv ₃ are preferably a phenyl group which may have a substituent, a branched alkyl group or a cycloalkyl group.

  X represents a methylene group which may have a substituent,> C═O,> C═S,> C═N—R. R represents a hydrogen atom or a substituent. X is preferably a methylene group which may have a substituent or> C═O.

  In order to immobilize the compound having a verdazyl structure according to the present invention on the electrode, it is preferable to have an adsorptive group in the molecule. Examples of the adsorptive group include the same groups as those exemplified in the general formula (L). It is also effective to contain a polymerizable group such as a vinyl group or (meth) acryloyl group in the molecule and fix it on the electrode surface as a polymer.

  Although the details of the mechanism of action of the compound having a verdazyl structure according to the present invention are unknown, the compound having a verdazyl structure can be reversibly oxidized and reduced as shown by the following formula. The repeated durability of the display dye seems to be improved compared to the case where only the dye is oxidized and reduced.

  Although the specific example of a compound represented by general formula (V) below is shown, this invention is not limited to these.

<< N-oxyl derivative >>
In the present invention, an N-oxyl derivative may be used in combination with the compound having the veldazyl structure. The N-oxyl derivative may function as a mediator for an electrodeposition reaction or an electrochromic reaction, or may function as a counter electrode reactant. When functioning as a mediator, it is desirable to have the same polarity as that of an electrodeposition reaction or electrochromic reaction. When functioning as a counter electrode reactant, it is different from that of an electrodeposition reaction or electrochromic reaction. It is desirable to have polar activity.

  The N-oxyl derivative according to the present invention may be contained in the electrolyte or may be immobilized on the electrode surface. Examples of the method of immobilizing on the electrode surface include a method of introducing a group that chemically or physically adsorbs with the electrode surface into the N-oxyl derivative, a method of forming a thin film on the electrode surface by polymerizing the N-oxyl derivative, and the like. Can be mentioned. The N-oxyl derivative may be added in the form of an N-oxyl radical, or may be added in the form of an N-hydroxy compound.

《Metal salt compound》
The display element of the present invention preferably contains a metal salt compound between the counter electrodes.

  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 deposited by driving the counter electrode on at least one electrode on the counter electrode. Also good. Preferred metal species are silver, bismuth, copper, nickel, iron, chromium, zinc, etc., more preferably silver and bismuth, and particularly preferred is silver.

  The metal ion concentration contained in the electrolyte according to the present invention is preferably 0.2 mol / kg ≦ [Metal] ≦ 2.0 mol / kg. If the metal ion concentration is 0.2 mol / kg or more, a metal 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.

(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.

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

Formula (1): 0 ≦ [X] / [Metal] ≦ 0.1
In the present invention, the halogen atom means an iodine atom, a chlorine atom, a bromine atom, or a fluorine atom. When [X] / [Metal] is greater than 0.1, 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.

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

  In the display element of this invention, it is preferable that electrolyte contains at least 1 sort (s) of the compound represented by the following general formula (G1) or (G2).

General Formula _{(G1) Rg 11 -S-Rg} 12
In the formula, 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 take a cyclic structure.

In the formula, 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, Rg ₂₁ represents a substituent, and when n is 2 or more, each Rg ₂₁ may be the same or different, and is linked to each other to form a condensed ring. May be.

  The compound represented by the general formula (G1) or (G2) is a compound that promotes solubilization of a metal, for example, silver in an electrolyte in order to cause dissolution and precipitation of a metal, for example, silver in the present invention.

  In general, in order to cause dissolution and precipitation of a metal, it is necessary to solubilize the metal in the electrolyte, for example, a metal that generates a metal coordination bond or a weak covalent bond with the metal. A compound containing a chemical structural species that interacts with is 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 metal solvents and It has a feature that it has little influence on coexisting compounds and high solubility in a solvent.

(Compound represented by General Formula (G1))
The compound represented by General Formula (G1) will be described in detail.

In the general formula (G1), Rg ₁₁ and Rg ₁₂ each represents a substituted or unsubstituted hydrocarbon group. 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.

  Hereinafter, although the specific example of a compound represented by general formula (G1) based on this invention is shown, this invention is not limited to these 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 =} ) NHCH 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 (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 ⁻

  Among the above-exemplified compounds, Exemplified Compound G1-2 is particularly preferable from the viewpoint that the objective effect of the present invention can be exhibited.

(Compound represented by formula (G2))
Next, the compound represented by formula (G2) according to the present invention will be described.

Examples of the metal atom represented by M in the general formula (G2) include Li, Na, K, Mg, Ca, Zn, and Ag. Examples of the quaternary ammonium include NH ₄ , N (CH ₃ ) ₄ , N (C ₄ H ₉ ) ₄ , N (CH ₃ ) ₃ C ₁₂ H ₂₅ , N (CH ₃ ) ₃ C ₁₆ H ₃₃ , N (CH ₃ ) ₃ CH ₂ C ₆ H _{5 and the} like It is done.

  Examples of the nitrogen-containing heterocycle having Z as a constituent in the general formula (G2) include, for example, a tetrazole ring, a triazole ring, an imidazole ring, an oxadiazole ring, a thiadiazole ring, an indole ring, an oxazole ring, a benzoxazole ring, and a benzimidazole. Ring, benzothiazole ring, benzoselenazole ring, naphthoxazole ring and the like.

The substituents represented by Rg ₂₁ of the general formula (G2), is not particularly limited, include, for example, substituents as described below.

  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 groups (eg, phenyl, naphthyl, etc.), alkylcarbonamide groups (eg, acetylamino, propionylamino, butyroylamino, etc.), arylcarbonamide groups ( For example, benzoylamino etc.), alkylsulfonamide groups (eg methanesulfonylamino group, ethanesulfonylamino group etc.), arylsulfonamide groups (eg benzenesulfonylamino group, toluenesulfonylamino group etc.), Alkyloxy group (eg, phenoxy), alkylthio group (eg, methylthio, ethylthio, butylthio, etc.), arylthio group (eg, phenylthio group, tolylthio group, etc.), alkylcarbamoyl group (eg, methylcarbamoyl, dimethylcarbamoyl, ethylcarbamoyl, diethyl) Carbamoyl, dibutylcarbamoyl, piperidylcarbamoyl, morpholylcarbamoyl, etc.), arylcarbamoyl groups (eg, phenylcarbamoyl, methylphenylcarbamoyl, ethylphenylcarbamoyl, benzylphenylcarbamoyl, etc.), alkylsulfamoyl groups (eg, methylsulfamoyl, Dimethylsulfamoyl, ethylsulfamoyl, diethylsulfamoyl, dibutylsulfamoyl, piperidylsulfamoy , Morpholylsulfamoyl, etc.), arylsulfamoyl groups (eg, phenylsulfamoyl, methylphenylsulfamoyl, ethylphenylsulfamoyl, benzylphenylsulfamoyl, etc.), alkylsulfonyl groups (eg, methanesulfonyl) Group, ethanesulfonyl group, etc.), arylsulfonyl group (for example, phenylsulfonyl, 4-chlorophenylsulfonyl, p-toluenesulfonyl, etc.) alkoxycarbonyl group (for example, methoxycarbonyl, ethoxycarbonyl, butoxycarbonyl, etc.), aryloxycarbonyl group ( For example, phenoxycarbonyl etc.), alkylcarbonyl groups (eg acetyl, propionyl, butyroyl etc.), arylcarbonyl groups (eg benzoyl group, alkylbenzoyl groups etc.), acyl Ruoxy 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, tetraazaindolizine ring group). These substituents further include those having a substituent.

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

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

  In the display element of the present invention, the electrolyte preferably contains a compound represented by the following general formula (S1) or (S2).

In the formula, L represents an oxygen atom or an alkylene group, and Rs _{11 to} Rs ₁₄ each represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group, or an alkoxy group.

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

(Compound represented by formula (S1))
First, the compound represented by formula (S1) will be described in detail.

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 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, this invention is not limited to these compounds.

(Compound represented by formula (S2))
Subsequently, the detail of the compound represented by general formula (S2) is demonstrated.

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, this invention is not limited to these 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 kind of electrolyte solvents. However, in the display element of the present invention, other solvents are used as long as the object effects of the present invention are not impaired. Can be used together. Specific examples of other solvents include tetramethylurea, sulfolane, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, 2- (N-methyl) -2-pyrrolidinone, hexamethylphosphotriamide, N- Methyl propionamide, 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 Over mono-butyl 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. As for the addition amount of ethylene carbonate, 10-90 mass% of the total electrolyte solvent mass is preferable. A particularly preferable electrolyte solvent is a mixed solvent having a mass ratio of propylene carbonate / ethylene carbonate of 7/3 to 3/7. When the propylene carbonate ratio is larger than 7/3, the ionic conductivity is inferior and the response speed is lowered. When the propylene carbonate ratio is smaller than 3/7, the electrolyte tends to be deposited at a low temperature.

《White scattering material》
In the present invention, a white scatterer is contained from the viewpoint of further enhancing the display contrast and the white display reflectance. The white scattering material may be present by forming a porous white scattering layer.

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

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

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

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

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

Examples of water-soluble compounds include proteins such as gelatin and gelatin derivatives, cellulose derivatives, natural compounds such as starch, gum arabic, dextran, pullulan, and carrageenan, and the like, polyvinyl alcohol, polyvinyl pyrrolidone, acrylamide polymers, and the like. Examples include synthetic polymer compounds such as derivatives. As gelatin derivatives, acetylated gelatin, phthalated gelatin, polyvinyl alcohol derivatives as terminal alkyl group-modified polyvinyl alcohol, terminal mercapto group-modified polyvinyl alcohol, and cellulose derivatives include hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose and the like. It is done. 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. Or a homopolymer of vinyl monomers having —COOM or —SO ₃ M (M is a hydrogen atom or an alkali metal) or vinyl monomers or other vinyl monomers (for example, sodium methacrylate, Copolymers with ammonium methacrylate, potassium acrylate, etc.) are also used. Two or more of these binders can be used in combination.

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

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

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

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

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

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

  Porous as used in the present invention refers to the formation of a porous white scattering material by applying a water mixture of the water-based compound and the white pigment onto an electrode and drying it, and then a metal or metal is chemically formed 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 metal dissolution and 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 hardeners 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, 61-18942, 61-249054, 61-245153, JP-A-4-284444, and the like. More specifically, aldehyde hardeners (formaldehyde, etc.), aziridine hardeners, epoxy hardeners, vinyl sulfone hardeners (N, N'-ethylene-bis (vinylsulfonylacetamide) Ethane, etc.), N-methylol hardeners (dimethylolurea, etc.), boric acid, metaboric acid or polymer hardeners (compounds described in JP-A-62-234157). When gelatin is used as the aqueous compound, it is preferable to use a vinyl sulfone type hardener or a chlorotriazine type hardener alone or in combination. Moreover, when using polyvinyl alcohol, it is preferable to use boron-containing compounds such as boric acid and metaboric acid.

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

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

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

  As a method for forming a porous film, a sintering method (a fusion method, using fine pores formed by adding polymer fine particles or inorganic particles to a binder and partially fusing them), an extraction method (solvent After forming a constituent layer with a soluble organic or inorganic substance and a binder that does not dissolve in the solvent, the organic or inorganic substance is dissolved with a solvent to obtain pores), and the polymer is heated or degassed, etc. Known forming methods such as a foaming method for foaming, a phase change method for phase separation of a mixture of polymers by operating a good solvent and a poor solvent, and a radiation irradiation method for forming pores 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-2895523, JP-A-2987474, JP-A-3066426. No. 3,464,513, No. 3,483,464, No. 3535942, No. 30602203, and the like.

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

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

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

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

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

Additive RD17643 RD18716 RD308119
Page Classification Page Classification Page Classification Chemical sensitizer 23 III 648 Upper right 96 III
Sensitizing dye 23 IV 648-649 996-8 IV
Desensitizing dye 23 IV 998 IV
Dye 25-26 VIII 649-650 1003 VIII
Development accelerator 29 XXI 648 Upper right Anti-fogging agent / stabilizer
24 IV 649 Upper right 1006-7 VI
Brightener 24 V 998 V
Hardener 26 X 651 Left 1004-5 X
Surfactant 26-7 XI 650 Right 1005-6 XI
Antistatic agent 27 XII 650 Right 1006-7 XIII
Plasticizer 27 XII 650 Right 1006 XII
Slipper 27 XII
Matting agent 28 XVI 650 Right 1008-9 XVI
Binder 26 XXII 1003-4 IX
Support 28 XVII 1009 XVII
"substrate"
Examples of the substrate that can be used in the present invention include polyolefins such as polyethylene and polypropylene, polycarbonates, cellulose acetate, polyethylene terephthalate, polyethylene dinaphthalene dicarboxylate, polyethylene naphthalates, polyvinyl chloride, polyimide, and polyvinyl acetal. Synthetic plastic films such as polystyrene can also be preferably used. Syndiotactic polystyrenes are also preferred. These can be obtained, for example, by the methods described in JP-A Nos. 62-117708, 1-46912 and 1-178505. Further, a metal substrate such as stainless steel, a paper support such as baryta paper and resin coated paper, and a support provided with a reflective layer on the plastic film, supported by JP-A-62-253195 (pages 29 to 31) The thing described as a body is mentioned. RDNo. 17643, page 28, ibid. No. 18716, page 647, right column to page 648, left column, and No. 307105, page 879 can also be preferably used. As these supports, those having resistance to curling due to heat treatment of Tg or less as in US Pat. No. 4,141,735 can be used. Further, the surface of these supports may be subjected to surface treatment for the purpose of improving the adhesion between the support and other constituent layers. In the present invention, glow discharge treatment, ultraviolet irradiation treatment, corona treatment, and flame treatment can be used as the surface treatment. Furthermore, the support body described in pages 44 to 149 of publicly known technology No. 5 (issued by Aztec Co., Ltd. on March 22, 1991) can also be used. Furthermore, RDNo. 308119, page 1009, Product Licensing Index, Volume 92, P108, “Supports”, and the like. In addition, a glass substrate or an epoxy resin kneaded with glass can be used.

<< 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.

  The sealing agent is for sealing so that the electrolytic solution does not leak to the outside, also called a sealing agent, epoxy resin, urethane resin, acrylic resin, vinyl acetate resin, ene-thiol resin, Curing types such as a thermosetting type, a photocuring type, a moisture curing type, and an anaerobic curing type such as a silicon-based resin and a modified polymer resin 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 maintain an appropriate interval between the substrates, 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 for uniformly holding a gap between the substrates may be provided between the pair of substrates. Examples of the spacer include a sphere made of resin or inorganic oxide. Further, a fixed spacer having a surface coated with a thermoplastic resin is also preferably used. In order to hold the gap between the substrates uniformly, only the columnar structure may be provided, but both the spacer and the columnar structure may be provided, or instead of the columnar structure, only the spacer is used as the space holding member. May be used. The diameter of the spacer is equal to or less than the height of the columnar structure, preferably equal to the height. When the columnar structure is not formed, the diameter of the spacer corresponds to the thickness of the cell gap.

<< Display element driving method >>
The method for controlling the transparent state and the colored state of the display element of the present invention is preferably determined based on the oxidation-reduction potential of the electrochromic dye and the deposition overvoltage of metal ions such as silver.

  For example, in the case of a display element having a compound represented by the general formula (L) and a silver compound between counter electrodes, a colored state other than black is shown on the oxidation side, and a black state is shown on the reduction side. As an example of the control method in this case, by applying a noble voltage from the oxidation-reduction potential of the compound represented by the general formula (L), the compound represented by the general formula (L) is oxidized and other than black Shows a colored state and reduces the compound represented by the general formula (L) to a white state by applying a voltage between the redox potential of the compound represented by the general formula (L) and the precipitation overvoltage of the silver compound. By applying a voltage lower than the deposition overvoltage of the silver compound, silver is deposited on the electrode to show a black state, and the oxidation potential of the deposited silver and the redox of the compound represented by the general formula (L) By applying a voltage between potentials, there is a method of dissolving and decoloring the precipitated silver.

  The driving operation of the display element of the present invention may be simple matrix driving or active matrix driving. The simple matrix driving in the present invention is a driving method in which a current is sequentially applied to a circuit in which a positive line including a plurality of positive electrodes and a negative electrode line including a plurality of negative electrodes are opposed to each other in a vertical direction. Say that. By using simple matrix driving, there is an advantage that the circuit configuration and driving IC can be simplified and manufactured at low cost. The active matrix drive is a system in which scanning lines, data lines, and current supply lines are formed in a grid pattern and are driven by a TFT circuit provided in each grid pattern. Since switching can be performed for each pixel, there are 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, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these.

Example 1 (white, color display)
<< Production of display element >>
[Production of display electrode]
(Preparation of electrode A1)
An ITO (Indium Tin Oxide) film having a pitch of 145 μm and an electrode width of 130 μm is 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 A1). It was.

(Preparation of electrode A2)
On the electrode A1, a titanium dioxide film having a thickness of 5 μm (about 4 to 10 particles having an average particle diameter of 17 nm was necked) was formed to obtain an electrode A2.

(Production of electrodes A3 to A7)
The following ink liquids a1 to a5 were applied onto the electrode A2 at 120 dpi using an inkjet apparatus having a piezo-type head to produce electrodes A3 to A7. In the present invention, dpi represents the number of dots per 2.54 cm.

<Preparation of ink liquids a1 to a5>
Ink liquids a1 to a5 were prepared by dissolving the EC dye and the veldazyl compound in an acetonitrile / ethanol mixed solvent (1/1) so as to have the concentrations shown in Table 1 below.

[Preparation of counter electrode]
(Preparation of electrode B1)
A nickel electrode having an electrode thickness of 0.1 μm, a pitch of 145 μm, and an electrode interval of 130 μm is formed on a glass substrate having a thickness of 1.5 mm and a size of 2 cm × 4 cm by using a known method. And a gold-nickel electrode (electrode B1) having a depth of 0.05 μm substituted with gold from the electrode surface was obtained.

(Preparation of electrode B2)
On the electrode B1, a titanium dioxide film having a thickness of 5 μm (about 4 to 10 particles having an average particle diameter of 17 nm was necked) was formed to obtain an electrode B2.

(Production of electrodes B3 to B7)
The following ink liquids b1 to b5 were applied onto the electrode B2 at 120 dpi using an inkjet apparatus having a piezo-type head to produce electrodes B3 to B5. In the present invention, dpi represents the number of dots per 2.54 cm.

<Preparation of ink liquids b1 to b5>
Ink liquids b1 to b5 were prepared by dissolving the veldazyl compound in an acetonitrile / ethanol mixed solvent (1/1) so as to have the concentrations shown in Table 2 below.

(Preparation of electrolyte)
(Preparation of electrolytes 1-1 to 1-9)
In the composition shown in Table 3 below, supporting salts, EC dyes and various additives were added to various solvents to prepare electrolytic solutions 1-1 to 1-9.

(Preparation of display element 1-1)
On the periphery of the electrode B1 bordered with an olefin-based sealant containing 10% glass spherical bead-shaped spacer having an average particle diameter of 40 μm as a volume fraction, polyvinyl alcohol (average polymerization degree 3500, saponification degree 87% ) Add 20% by mass of titanium dioxide CR-90 made by Ishihara Sangyo Co., Ltd. into an isopropanol solution containing 2% by mass, and apply the mixed liquid dispersed with an ultrasonic disperser so that the film thickness after drying is 20 μm. Then, after drying at 15 ° C. for 30 minutes to evaporate the solvent, it was dried in an atmosphere at 45 ° C. for 1 hour. After spraying glass spherical bead-shaped spacers having an average particle diameter of 20 μm on the obtained titanium dioxide layer, the electrode B1 and the electrode A1 were bonded together and heated and pressed to produce an empty cell. The electrolytic solution 1-2 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 1-1.

(Production of display elements 1-2 to 1-16)
In the production of the display element 1-1, display elements 1-2 to 1-16 were obtained in the same manner except that the electrolyte solution and the electrode were changed to the configurations described in Table 4.

<< Evaluation of display element >>
(Display element 1-1: Comparison)
A dull purple color was observed when both electrodes of the display element were connected to both terminals of the constant voltage power source and a voltage of +2.5 V was applied for 3 seconds. Next, by applying a voltage of −2.5 V for 3 seconds, a dull blue color was observed. In the display element 1-1, white could not be displayed even when the voltage was switched.

(Display element 1-2: Comparison)
By connecting both electrodes of the manufactured display element to both terminals of the constant voltage power source and applying a voltage of +2.5 V for 3 seconds, reddish brown coloring was observed. Next, by applying a voltage of −2.5 V for 3 seconds, a light reddish brown color was observed. The display element 1-2 could not display white even when the voltage was switched.

(Display element 1-3: Comparison)
By connecting both electrodes of the manufactured display element to both terminals of the constant voltage power source and applying a voltage of +3.0 V for 3 seconds, red coloring was recognized. Next, by applying a voltage of −3.0 V for 3 seconds, although a slightly purple color was displayed, a substantially white display was obtained, but the applied voltage was changed to ± 1.5 V and the same operation was performed. As a result, no clear color change was observed.

(Display element 1-4: the present invention)
By connecting both electrodes of the manufactured display element to both terminals of the constant voltage power source and applying a voltage of -1.5 V for 1 second, blue coloring was recognized. Next, a white display was obtained by applying a voltage of +1.5 V for 1 second.

(Display elements 1-5 to 1-16: the present invention)
By connecting both electrodes of the manufactured display element to both terminals of the constant voltage power source and applying a voltage of +1.5 V for 1 second, red coloring was observed in all the display elements. Subsequently, a white display was obtained by applying a voltage of -1.5 V for 1 second.

[Evaluation of reflectance stability when driven repeatedly]
Both electrodes of the produced display element were connected to both terminals of the constant voltage power source, and positive and negative voltages were applied at the times shown in Table 5 to display a colored state and a white state. The reflectance at the maximum absorption wavelength in the visible light region when colored and displayed was measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing. The drive was performed a total of 10 times under the same drive conditions, and the average value of the obtained reflectance was _Rave1 . Further, after driving repeatedly 10,000 times, R _ave2 was obtained in the same manner. ΔR _COLOR = | (R _{ave1 −Rave2} ) / R _ave1 | was used as an index of the stability of the reflectance when ΔR _COLOR was repeatedly driven. Here, the smaller the value of ΔR _COLOR, the better the stability of the reflectance when it is repeatedly driven.

  As is clear from the results shown in Table 5, the comparative display elements 1-1 and 1-2 could not display white. The comparative display element 1-3 can display white, but requires a relatively high voltage and a long time. In contrast, the display elements 1-4 to 1-16 of the present invention were capable of white display and color display in a relatively low voltage and in a short time. In addition, it can be seen that the display element of the present invention has improved reflectance stability when driven repeatedly compared to the comparative example.

Example 2 (white, black, color display)
<< Production of display element >>
As the display electrode and the counter electrode, the electrode produced by the method of Example 1 was used.

(Preparation of electrolyte)
(Preparation of electrolytic solutions 2-1 to 2-11)
With the compositions shown in Table 6 below, supporting salts, EC dyes and various additives were added to various solvents to prepare electrolytic solutions 2-1 to 2-11.

(Preparation of display element 2-1)
On the periphery of the electrode B1 bordered with an olefin-based sealant containing 10% glass spherical bead-shaped spacer having an average particle diameter of 40 μm as a volume fraction, polyvinyl alcohol (average polymerization degree 3500, saponification degree 87% ) Add 20% by mass of titanium dioxide CR-90 made by Ishihara Sangyo Co., Ltd. into an isopropanol solution containing 2% by mass, and apply the mixed liquid dispersed with an ultrasonic disperser so that the film thickness after drying is 20 μm. Then, after drying at 15 ° C. for 30 minutes to evaporate the solvent, it was dried in an atmosphere at 45 ° C. for 1 hour. After sprinkling glass spherical bead spacers having an average particle diameter of 20 μm on the obtained titanium dioxide layer, the electrode B1 and the electrode A1 were bonded together and heated and pressed to produce an empty cell. Electrolyte 2-2 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 2-1.

(Production of display elements 2-2 to 1-17)
Display elements 2-2 to 2-17 were obtained in the same manner as in the manufacture of the display element 2-1, except that the electrolyte solution and the electrodes were changed to the configurations described in Table 7.

<< Evaluation of display element >>
[Evaluation of reflectance stability when driven repeatedly]
Connect both electrodes of the display element to both terminals of the constant voltage power supply, apply the negative voltage shown in Table 8 for a predetermined time and display gray, and apply the positive voltage shown in Table 8 for a predetermined time. The reflectance at the maximum absorption wavelength in the visible light region when colored and displayed was measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing. Under the same driving conditions, driving was performed 10 times in total, and the average values of the obtained gray reflectance and colored reflectance were calculated separately, and were _designated as R _ave3 and R _ave4 , respectively. Further, after driving repeatedly 10,000 times, R _ave5 and R _ave6 were obtained by the same method. ΔR _BK = | (R _{ave3 −Rave 5} ) / R _ave3 |, ΔR _COLOR2 = | (R _ave4 −R _ave6 ) / R _ave4 |, and index of stability of reflectance when ΔR _BK and ΔR _COLOR2 are repeatedly driven It was. Here, the smaller the values of ΔR _BK and ΔR _COLOR2 , the _better the stability of the reflectance when repeatedly driven.

  As is apparent from the results shown in Table 8, it can be seen that the display element of the present invention has improved reflectance stability when it is repeatedly driven as compared with the comparative example.

Claims (6)

Between the counter electrodes, containing at least one electrochromic dye, an electrolyte, and a white scatterer that reversibly develop or decolorize by at least one of an electrochemical oxidation reaction and a reduction reaction, and by driving the counter electrode, A display element that changes color tone, wherein the electrochromic dye is immobilized on an electrode surface, and the display element has a compound having a veldazil structure between opposing electrodes. The display device according to claim 1, wherein the compound having a veldazil structure is represented by the following general formula (V).

(Wherein Rv _{1 to} Rv ₃ each represents an aromatic group, an aliphatic group or a heterocyclic group which may have a substituent, X represents a methylene group which may have a substituent,> C═O ,> C = S,> C = N—R, where R represents a hydrogen atom or a substituent.) The display element according to claim 1, wherein the electrochromic dye is colored by an oxidation reaction. The display element according to claim 1, wherein the electrochromic dye is a compound represented by the following general formula (L).

(In the formula, Rl ₁ represents a substituted or unsubstituted aryl group, 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 metal salt compound is contained between the counter electrodes, and multi-color display of three or more colors of black display, white display, and color display other than black is performed by driving the counter electrode. The display element according to claim 1. The display element according to claim 5, wherein the metal salt compound is a silver salt compound.