WO2009116352A1 - Display element - Google Patents

Abstract

Disclosed is a display element having a simple member configuration, which can be driven at a low voltage. The display element is suppressed in reflectance changes during repeated operations. The display element contains, between a pair of opposing electrodes, an electrolyte, a compound the color of which is reversibly changed by an electrochemical redox reaction, and a redoxable auxiliary compound which accelerates the electrochemical redox reaction. The display element shows a white or colored display by driving the pair of opposing electrodes, and is characterized in that the solvent of the electrolyte is an aprotic polar solvent containing a compound represented by general formula (GI). Rf-L-X-Ar-Ball (GI) In the general formula, Rf represents a perfluoroalkyl group; L represents an optionally substituted alkyl group or a bonding hand; X represents a sulfur atom, an oxygen atom or an N-Rn group (wherein Rn represents a hydrogen atom or a substituent); Ar represents an optionally substituted divalent aromatic group; and Ball represents a hydrophobic group having 5 or more carbon atoms.)

Description

Display element

The present invention relates to a novel electrochemical display element that does not leak an organic solvent or the like and can be driven at a low voltage and has high durability.

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 increasingly 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. Generally, as a drawback of light-emitting displays, eyes flicker due to flickering, inconvenient to carry, reading posture is limited It is known that it is necessary to adjust the line of sight to a still screen, and that power consumption increases when read for a long time.

As a display means to compensate for these drawbacks, a reflection type display 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.

In other words, the method using a polarizing plate such as a reflective liquid crystal has a low reflectance of about 40%, and thus it is difficult to display white, and many of the manufacturing methods used to manufacture 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 driving voltage and a complicated TFT circuit required to improve the memory performance. In addition, a display element based on electrophoresis requires a high voltage of 10 V or more, and there is a concern about durability due to electrophoretic particle aggregation.

As a display method for 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 (see, for example, Patent Documents 1 to 5).

Conventionally, a liquid electrolyte in which a supporting electrolyte is dissolved in water or an organic solvent has been used as an electrolyte of many electrochemical elements. However, the liquid electrolyte has problems in that it is difficult to leak the electrolyte due to aging or damage due to long-term storage of the electrochemical element, and to reduce the size and thickness. In particular, EC or ED display elements must be sealed with a transparent material such as glass or plastic in at least one direction for display applications. It is difficult to end up. For this reason, leakage and volatilization of the electrolyte become a larger problem.

Therefore, research and development of solid thin film electrolyte materials that solidify electrolytes, are easy to handle, have high safety, and have a high ion transport number have been actively conducted. For example, there is a solid polymer electrolyte in which a supporting electrolyte is dissolved in a polymer having a polyether structure such as polyethylene oxide, polypropylene oxide, or a derivative or copolymer thereof. Such a polymer having a polyether structure can dissolve one monovalent cation with four oxygen atoms in the ether structure. Although such a solid electrolyte basically does not contain a solution, the possibility of leakage is low, but its conductivity is about three orders of magnitude lower than that of a normal non-aqueous electrolyte. .

Also known is a gel electrolyte that includes a liquid electrolyte in a polymer matrix that forms a mesh. Such gel electrolytes can be polymerized in a liquid electrolyte mixed with monomers to produce a polymer swollen with the liquid electrolyte, or a polymer matrix that has been polymerized in advance is immersed in the liquid electrolyte to swell the polymer. Make it. In such a gel electrolyte, the polymer matrix basically has a function including a liquid electrolyte and does not contribute to ionic conduction, so that sufficient conductivity cannot be obtained.

Recently, gels have been attracting attention as solid electrolytes that are excellent in conductivity and uniformity and have sufficient solid strength to withstand use as solid electrolytes for electrochemical devices. It is known that a compound having a self-organization property (self-organization compound) that forms a fibrous aggregate by using an intermolecular force such as hydrogen bonding as a driving force gels a liquid with a small amount of addition (for example, (See Patent Documents 6 to 8).

However, as a result of examining the techniques disclosed in Patent Documents 6 to 8 in detail, in order to gel the electrolytic solution containing a large amount of the supporting electrolyte with the gelling agent, It has been found that a large amount of gelling agent has to be used, there is a problem that the original electrochemical characteristics are changed, and there is a problem in the stability of the reflectance when it is repeatedly driven.

On the other hand, Patent Documents 9 to 11 below describe that various solvents can be gelled by addition of a small amount of a specific perfluoroalkyl derivative and are preferable as gel electrolytes. It shows only the ability to form, and it does not show whether an electrolyte containing various additives can be gelled. Further, it has not been suggested that the effect of stabilizing the reflectance when repeatedly driven can be 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 Japanese Patent No. 2599763 JP 2001-167629 A JP 2006-235366 A JP 2007-191626 A JP 2007-191627 A JP 2007-191661 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 configuration.

1. An electrolyte, a compound that changes color reversibly by an electrochemical oxidation-reduction reaction, and an auxiliary compound that can be oxidized / reduced to promote the electrochemical oxidation-reduction reaction are contained between a pair of opposed electrodes. In the display element which performs white display and color display by the driving operation of the electrode, the solvent of the electrolyte is an aprotic polar solvent and includes a compound represented by the following general formula (GI) Display element.

General formula (GI) Rf-LX-Ar-Ball
(In the formula, Rf represents a perfluoroalkyl group, L represents an alkylene group which may have a substituent, or a simple bond. X represents a sulfur atom, an oxygen atom or N—Rn. Rn represents a hydrogen atom. Or represents a substituent, Ar represents a divalent aromatic group which may have a substituent, and Ball represents a hydrophobic group having 5 or more carbon atoms.)
2. 2. The display device according to 1 above, wherein the compound represented by the general formula (GI) is a compound represented by the following general formula (GII).

General formula (GII) Rf-L—X—Ar—Y—R
(In the formula, Rf represents a perfluoroalkyl group, L represents an alkylene group which may have a substituent, or a simple bond. X represents a sulfur atom, an oxygen atom or N—Rn. Rn represents a hydrogen atom. Alternatively, Ar represents a divalent aromatic group which may have a substituent, Y represents a linking group that binds to Ar by an oxygen atom, a sulfur atom, or a nitrogen atom, and connects Ar and R. R represents an aliphatic group having 5 or more carbon atoms which may have a substituent.
3. 3. The display element according to 1 or 2 above, wherein the compound that reversibly discolors by the electrochemical oxidation-reduction reaction is an electrochromic compound.

4. 4. The display element according to 3 above, wherein the electrochromic compound is represented by the following general formula (L).

(Wherein 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). 5. The display element according to 3 or 4 above, wherein the auxiliary compound capable of being oxidized and reduced that promotes an electrochemical reaction of the electrochromic compound is an N-oxyl derivative.

6. 6. The display device according to any one of 1 to 5, wherein the compound that reversibly discolors by the electrochemical redox reaction is a metal salt compound.

7. 7. The display element according to 6 above, wherein the metal salt compound is a silver salt compound.

8. 8. The display element according to 6 or 7 above, wherein a compound represented by the following general formula (G1) or a compound represented by the general formula (G2) is contained between the pair of opposed electrodes.

Formula (G1) Rg ₁₁ -S-Rg ₁₂
(Wherein 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 atoms, halogen atoms are substituted. And Rg ₁₁ and Rg ₁₂ may be linked to each other to form 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, and Rg ₂₁ represents a substituent. In the case where n is 2 or more, each Rg ₂₁ may be the same or different, and may be linked to each other to form a condensed ring.
9. 9. The method according to any one of 6 to 8, wherein a multi-color display of three or more colors, substantially black display, white display, and color display other than black, is performed by driving the pair of opposed electrodes. Display element.

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.

As a result of intensive studies in view of the above problems, the present inventors have promoted an electrolyte, a compound that reversibly changes color due to an electrochemical redox reaction, and the electrochemical redox reaction between a pair of opposed electrodes. A display element containing an auxiliary compound that can be oxidized and reduced, and performing white display and color display by driving the pair of opposed electrodes, wherein the solvent of the electrolyte is an aprotic polar solvent, and a gelling agent 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 by using a display element containing the compound represented by the general formula (GI) as As a result, the present invention has been found.

Hereinafter, details of the present invention will be described.

<< Basic configuration of display element >>
In the display element of the present invention, the display portion is provided with one of a pair of opposing electrodes. The electrode 1, which is one of the 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. Between the electrode 1 and the electrode 2, an electrolyte according to the present invention and a compound that reversibly discolors by an electrochemical redox reaction are contained. By applying a voltage of positive and negative polarity between a pair of opposing electrodes, the white and various colored states are reversible by coloring / decoloring reaction by oxidation / reduction of a compound that reversibly discolors by electrochemical oxidation-reduction reaction. Can be switched automatically.

Also, an auxiliary compound (promoter) that can be oxidized and reduced, which will be described later, is added in order to promote the electrochemical reaction of the compound that reversibly changes color due to the electrochemical oxidation-reduction reaction.

Examples of the compound that reversibly discolors by an electrochemical redox reaction include a metal salt compound that dissolves and precipitates reversibly by an electrochemical redox reaction with an electrochromic compound.

A preferred embodiment is that both an electrochromic compound and a metal salt compound are contained as a compound that reversibly changes color by an electrochemical redox reaction. In this embodiment, by applying a voltage of positive and negative polarity between a pair of electrodes facing each other, black and white display accompanying dissolution and precipitation of the metal salt compound is performed, and coloring / decoloring reaction by oxidation / reduction of the electrochromic compound In addition, the colored states other than black, white, and black can be switched reversibly.

In a more preferred embodiment of the present invention, the electrochromic compound is immobilized on the transparent electrode 1 on the display side.

"electrode"
(Display electrode)
In the display element of the present invention, a transparent electrode is used on the display portion side of a pair of opposed 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.

(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 electrochromic dye (hereinafter also referred to as EC dye) or the like on the surface and inside thereof. The specific surface area of the semiconductor nano-porous layer is preferably 1 ~ 5000m ² / g, more preferably 10 ~ 2500m ² / g. 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, 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, more preferably 5 to 25000.

(Counter electrode)
In the display element of the present invention, a metal electrode or a carbon electrode is used as an electrode that is not the display portion side electrode among the pair of electrodes facing each other.

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 having a work function close to the redox potential of silver in the electrolyte. Among them, silver or a silver electrode having a silver content of 80% or more is advantageous for maintaining the reduced state of silver. Excellent in preventing dirt. 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.

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

《Gelling agent》
One feature of the present invention is that a compound represented by the general formula (GI), more preferably the general formula (GII) is used as the gelling agent for the electrolyte.

In General Formula (GI), Rf represents a perfluoroalkyl group, and L represents an alkylene group which may have a substituent or a simple bond. X represents a sulfur atom, an oxygen atom or N—Rn. Rn represents a hydrogen atom or a substituent. Ar represents a divalent aromatic group which may have a substituent, and Ball represents a hydrophobic group having a total carbon number of 5 or more.

In the general formula (GI), the perfluoroalkyl group represented by Rf means a group in which all hydrogen atoms of a linear, branched, or cyclic alkyl group are substituted with fluorine atoms. The number of carbon atoms of the group represented by Rf is not particularly limited, but a linear perfluoroalkyl group having 6 to 12 carbon atoms is preferred because of its strong gelling ability.

In general formula (GI), L is preferably an alkylene group which may have a substituent. When L represents alkylene which may have a substituent, the substituent is not particularly limited, but perfluoroalkylene groups in which all substitution positions are substituted with fluorine atoms are excluded by definition. As the alkylene group represented by L, a linear unsubstituted alkylene group having 1 to 4 methylene chains connected is preferable, and an ethylene group, a trimethylene group, and a tetramethylene group are particularly preferable.

In the general formula (GI), when X represents N—Rn, Rn represents a hydrogen atom or a substituent. Although there is no restriction | limiting in particular in the substituent represented by Rn, The alkyl group which may have a substituent is preferable. X is particularly preferably a sulfur atom or an oxygen atom.

In General Formula (GI), Ar represents a divalent aromatic group which may have a substituent, and may be a divalent aromatic hydrocarbon group or an aromatic heterocyclic group, Phenylene group, biphenylene group, terphenylene group, naphthylene group, anthranylene group, phenanthrylene group, pyrenylene group, chryselin group, fluoranthenylene group, pyrrolene group, furanylene group, thiophenylene group, triazolen group, oxadiazolene group, pyridylene Group, pyrimidylene group and the like. As the group represented by Ar, a phenylene group, a biphenylene group or a naphthylene group which may have a substituent is particularly preferable.

In General Formula (GI), the group represented by Ball is not particularly limited as long as it is a hydrophobic group having 5 or more carbon atoms. For example, an alkyl group having 5 or more carbon atoms (for example, a pentyl group, a cyclohexyl group, t -Octyl group, nonyl group, dodecyl group, etc.), alkoxy group (for example, pentyloxy group, hexyloxy group, dodecyloxy group, tetradecyloxy group), alkylthio group (for example, pentylthio group, hexylthio group, dodecylthio group, tetradecylthio group) Group) and a dialkylamino group (for example, a dibutylamino group, a dihexylamino group, etc.) are preferable. These groups may further have a substituent. The group represented by Ball may be a polyvalent linking group. That is, the compound represented by the general formula (GI) may be a multimer having a plurality of groups represented by Rf-L—X—Ar— in the molecule.

In General Formula (GII), Rf represents a perfluoroalkyl group, and L represents an alkylene group which may have a substituent or a simple bond. X represents a sulfur atom, an oxygen atom or N—Rn. Rn represents a hydrogen atom or a substituent. Ar represents a divalent aromatic group which may have a substituent, and Y represents a linking group that binds to Ar by an oxygen atom, a sulfur atom, or a nitrogen atom and connects Ar and R. R represents an aliphatic group having 5 or more carbon atoms which may have a substituent.

In the general formula (GII), Rf, L, X, Ar are synonymous with Rf, L, X, Ar in the general formula (GI). Y in the general formula (GII) is —O—, —O—CO—, —O—CO—O—, —O—CO—NR′—, —O—, —NR′—, —NR′—. CO-, -NR'-CO-O-, -NR'-CO-NR'- and the like. These linking groups are substituted with Ar at the left-hand bond and bonded to R at the right. R ′ represents a hydrogen atom or a substituent. The linking group represented by Y is preferably —O— or —S—.

Examples of R in the general formula (GII) include linear or branched, cyclic alkyl groups, alkenyl groups, and alkynyl groups having 5 or more carbon atoms. These groups may further have a substituent. The group represented by R is preferably an alkyl group having 5 or more carbon atoms (for example, pentyl group, cyclohexyl group, t-octyl group, decyl group, dodecyl group, tetradecyl group). The upper limit of the carbon number is not particularly limited, but is preferably 20 or less, and particularly preferably 14 or less, from the viewpoint of availability of raw materials and ease of handling.

The compounds represented by general formula (GI) and general formula (GII) can be easily synthesized with reference to Patent Documents 9 to 11.

The amount of the compound represented by general formula (GI) or general formula (GII) can be used in the range of 0.1 to 30% by mass with respect to the solvent of the electrolyte to be used. A preferable addition amount is in a range of 0.5 to 10% by mass, and a range of 1 to 5% by mass is particularly preferable.

Examples of the compounds represented by the general formula (GI) and the general formula (GII) are shown below, but the present invention is not limited to these.

《Compounds reversibly discolored by electrochemical redox reactions》
The compound reversibly discolored by the electrochemical redox reaction according to the present invention refers to an electrochromic compound and a metal salt compound described below.

[Electrochromic compound (hereinafter referred to as EC compound or EC dye)]
The EC compound 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. EC compounds include tungsten oxide, iridium oxide, nickel oxide, cobalt oxide, vanadium oxide, molybdenum oxide, titanium oxide, indium oxide, chromium oxide, manganese oxide, Prussian blue, indium nitride, tin nitride, zirconium nitride chloride, etc. In addition to compounds, organometallic complexes, conductive polymer compounds, and organic dyes are known.

Examples of organometallic complexes exhibiting EC characteristics include metal-bipyridyl complexes, metal phenanthroline complexes, metal-phthalocyanine complexes, rare earth diphthalocyanine complexes, and ferrocene dyes.

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

In addition, a polymer material composed of a bisterpyridine derivative and a metal ion as described in, for example, JP-A-2007-112957 also exhibits EC characteristics.

Organic dyes exhibiting EC characteristics include pyridinium compounds such as viologen, azine dyes such as phenothiazine, styryl dyes, anthraquinone dyes, pyrazoline dyes, fluorane dyes, donor / acceptor compounds (for example, tetracyanoquinodis Methane, tetrathiafulvalene) and the like. In addition, compounds known as redox indicators and pH indicators can also be used.

EC compounds are classified into the following three classes when classified in terms of color change.
Class 1: EC compounds that change from one specific color to another by redox.
Class 2: EC compounds that are substantially colorless in the oxidized state and exhibit a specific colored state that is the reduced state.
Class 3: EC compounds that are substantially colorless in the reduced state and exhibit a particular colored state that is the oxidized state.

In the display element of the present invention, the above class 1 to class 3 EC compounds can be appropriately selected depending on the purpose and application.

(Class 1 EC compounds)
Class 1 EC compounds are EC compounds that change from a specific color to another color by oxidation-reduction, and are compounds capable of displaying two or more colors in their possible oxidation states.

As compounds classified into class 1, for example, V ₂ O ₅ changes from orange to green by changing from an oxidation state to a reduction state, and similarly Rh ₂ O ₃ changes from yellow to dark green.

Many of the organometallic complexes are classified as class 1, and ruthenium (II) bipyridine complexes, such as tris (5,5'-dicarboxylethyl-2,2'-bipyridine) ruthenium complexes, are between +2 and -4 valences, The color changes from orange to purple, blue, green blue, brown, red rust and red. Many of the rare earth diphthalocyanines also exhibit such multicolor characteristics. For example, in the case of lutetium diphthalocyanine, the color gradually changes from purple to blue, green, and red-orange according to oxidation.

Many of the conductive polymers are also classified as class 1. For example, polythiophene changes from blue to red by changing from an oxidized state to a reduced state, and polypyrrole changes from brown to yellow. In addition, polyaniline or the like exhibits multi-color characteristics and changes from an amber color of an oxidation state to blue, green, and light yellow in order.

EC compounds classified as class 1 have a merit that multicolor display is possible with a single compound, but on the other hand, they have a drawback that a state that can be said to be virtually colorless cannot be made.

(Class 2 EC compounds)
Class 2 EC compounds are compounds that are colorless or extremely light in an oxidized state and exhibit a specific colored state that is a reduced state.

Examples of the inorganic compounds classified as class 2 include the following compounds, each of which shows the color shown in parentheses in the reduced state. WO ₃ (blue), MnO ₃ (blue), Nb ₂ O ₅ (blue), TiO ₂ (blue), etc.

Examples of organometallic complexes classified as class 2 include tris (vasophenanthroline) iron (II) complexes, which show red in the reduced state.

Examples of organic dyes classified as class 2 include compounds described in JP-A Nos. 62-71934 and 2006-71765, such as dimethyl terephthalate (red) and 4,4′-biphenylcarboxylic acid. Examples thereof include diethyl acid (yellow), 1,4-diacetylbenzene (cyan), and tetrazolium salt compounds described in JP-A Nos. 1-230026 and 2000-504774.

The most representative dyes classified in class 2 are pyridinium compounds such as viologen. Viologen compounds have the advantages of clear display and the ability to have color variations by changing substituents, etc., so they are the most actively studied among organic dyes. ing. Color development is based on organic radicals generated by reduction.

Examples of pyridinium-based compounds such as viologen include compounds described in the following patents including, for example, JP-T 2000-506629.

JP-A-5-70455, JP-A-5-170738, JP-A-2000-235198, JP-A-2001-114769, JP-A-2001-172293, JP-A-2001-181292, JP-A-2001-181293, JP-T-2001-510590. JP-A-2004-101729, JP-A-2006-154683, JP-T-2006-519222, JP-A-2007-31708, JP-A-2007-171781, JP-A-2007-219271, JP-A-2007-219272, 2007-279659 No. 2007-279570, 2007-279571, 2007-279572, etc.

Examples of pyridinium compounds such as viologen that can be used in the present invention are shown below, but are not limited thereto.

(Class 3 EC compounds)
Class 3 EC compounds are compounds that are colorless or very pale in the reduced state and exhibit a specific colored state that is an oxidized state.

Examples of inorganic compounds classified into class 3 include iridium oxide (dark blue), Prussian blue (blue), etc. (each of which shows the color shown in parenthesis in the oxidized state).

There are few examples of conductive polymers classified into class 3, but examples thereof include phenyl ether compounds described in JP-A-6-263846.

Many dyes are known as class 3 dyes, styryl dyes, azine dyes such as phenazine, phenothiazine, phenoxazine, and acridine, azole dyes such as imidazole, oxazole, and thiazole are preferable. .

Examples of styryl dyes, azine dyes, and azole dyes that can be used in the present invention are shown below, but the invention is not limited thereto.

In a preferred embodiment of the present invention, a metal salt that reversibly dissolves and precipitates by an electrochemical redox reaction is used in combination with the EC dye, and a multicolor of three or more colors of black display, white display, and non-black color display. Display. In this case, since the metal salt is reduced to give a black display, the EC dye is preferably a class 3 EC compound that develops color by oxidation, and is particularly an azole series in terms of color development diversity, low driving voltage, memory properties, and the like. A dye is preferred. In the present invention, the most preferred 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, cycloalkenyl , 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, pen Ruoxy 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, cyclohexyla) Nosulfonyl group, phenylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), urethane group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, phenylureido group, 2-pyridylureido group, etc.), Acyl group (for example, acetyl group, propionyl group, butanoyl group, hexanoyl group, cyclohexanoyl group, benzoyl group, pyridinoyl group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propyl) Aminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, phenylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), acylamino group (eg acetylamino group, benzoyl group) Amino group, methylureido group, etc.), sulfonyl group (eg, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, phenylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (eg, amino group, Ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, anilino group, 2-pyridylamino group, etc.), halogen atom (eg chlorine atom, bromine atom, iodine atom etc.), cyano group, nitro group, sulfo group Carboxyl group, hydroxyl group, phosphono group (for example, phosphonoethyl group, phosphonopropyl group, phosphonooxyethyl group) and the like. Further, these groups may be further substituted with these groups.

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

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. Rl ₂ and Rl ₃ may be linked to each other to form a ring structure. As a combination of Rl ₂ and Rl ₃ , both of them may be a phenyl group or a heterocyclic group which may have a substituent, or one of them may be a phenyl group or a heterocyclic group which may have a substituent. Yes, the other is a combination of alkyl groups which may have a substituent.

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 having 5 to 10 carbon atoms, an acyl group It is a 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 a group that chemically or physically adsorbs 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 chemisorbable adsorptive group include —COOH, —P═O (OH) ₂ , —OP═O (OH) ₂ and —Si (OR) ₃ (R represents an alkyl group) is preferred.

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

In formula _{(L2), Rl 21, Rl} 22 is an aliphatic group, an aliphatic oxy group, an acylamino group, a carbamoyl group, an acyl group, a sulfonamido group, a sulfamoyl group, R1 ₂₃ is an aromatic group or an aromatic heterocyclic Rl ₂₄ represents a hydrogen atom, an aliphatic group, an aromatic group or an aromatic heterocyclic group, and Rl ₂₅ represents a hydrogen atom, an aliphatic group, an aromatic group or an acyl group.

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

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

Further, when the imidazole dye represented by the general formula (L2) is fixed on the electrode, at least one of the groups represented by Rl ₂₁ to Rl ₂₅ has a partial structure of —P═O (OH) ₂ , It is preferable to have —Si (OR) ₃ (R represents an alkyl group), and in particular, —Si (OR) ₃ (R represents an alkyl group) as a partial structure of the group represented by Rl ₂₃ or Rl ₂₄ It is preferable to have.

Specific examples of the EC dye represented by the general formula (L2) and specific examples of the EC dye contained in the general formula (L) that do not correspond to the general formula (L2) are shown below. The invention is not limited to these exemplified compounds.

"promoter"
In the display element of the present invention, an auxiliary compound (hereinafter referred to as a promoter) that can be oxidized and reduced is added in order to promote the electrochemical reaction of the compound that reversibly discolors due to the electrochemical redox reaction. The promoter may be one that does not change the optical density in the visible region (400 to 700 nm) as a result of the oxidation-reduction reaction, or one that changes, that is, a compound that reversibly discolors due to the electrochemical oxidation-reduction reaction. Alternatively, it may be fixed on the electrode, or may be added to the electrolyte. These promoters can be used, for example, as counter electrode reactants or as redox mediators.

For example, when a compound that reversibly changes color due to an electrochemical redox reaction on the display electrode side is oxidized (or reduced), a low drive is achieved by utilizing the reduction (or oxidation) reaction of the promoter on the counter electrode side. It is possible to obtain a high color density with voltage. Thus, when a promoter is used as a counter electrode reactant, it is preferable to use a promoter having a redox activity opposite to that of a compound reversibly discolored by an electrochemical redox reaction, immobilized on a counter electrode. . When a promoter is used as the counter electrode material, it is preferable that the promoter does not change the optical density in the visible region (400 to 700 nm) as a result of the redox reaction. However, as described in the preferred embodiment of the present invention, in the case of using a white scatterer in the display element to shield the color development by the promoter, the promoter in which the optical density in the visible region (400 to 700 nm) changes. That is, a compound that changes color reversibly by an electrochemical redox reaction may be used. Such a configuration is preferable because it facilitates selection of a promoter. As another embodiment, it is one of preferred embodiments to use a promoter that exhibits the same color as a compound that reversibly changes color by an electrochemical redox reaction on the display electrode side.

On the other hand, the redox mediator is a material generally used in the field of organic electrolytic synthesis. Each organic compound has an oxidation overvoltage that depends on the electrolysis method and electrolysis conditions, in addition to its own oxidation potential, and when the anode potential is higher than the combined oxidation potential, an oxidation reaction actually occurs. Due to experimental limitations on the anodic potential, it is not possible to oxidize all substrates by direct methods. When a substrate having a high oxidation potential is oxidized, no electron transfer from the substrate to the anode occurs. When a mediator that causes electron transfer (oxidation) to the anode at a low potential coexists in this reaction system, the mediator is first oxidized, and the substrate is oxidized by the oxidized mediator to obtain a product. The advantage of this reaction system is that it is possible to oxidize the substrate at an anodic potential lower than the oxidation potential of the substrate, and that the oxidized mediator returns to the original mediator when the substrate is oxidized. It acts as a catalytic amount. Further, since oxidation at a low potential is possible, decomposition of the substrate and product can be suppressed.

In the present invention, for example, when a compound that reversibly discolors by an electrochemical redox reaction that oxidizes and develops as the substrate, the display element is driven at a low driving voltage by coexisting a catalytic amount of an oxidation mediator. The durability of the display element is increased. Further, there are advantages such as an improvement in display switching speed and high color development efficiency. Similarly, the above effect can be obtained by a combination of a reducing mediator and a compound that reversibly discolors by an electrochemical redox reaction that produces a reduction color.

In the display element of the present invention, as shown in the field of organic electrosynthesis, a single mediator may be used, or a plurality of mediators may be used in combination. When a promoter is used as a mediator in the present invention, it is preferable to fix a compound that changes color reversibly by an electrochemical redox reaction on a display electrode and to localize the promoter in the vicinity thereof.

In the present invention, a promoter may be used as a counter electrode reactant or a mediator. For both purposes, a plurality of promoters may be used in combination at the same time.

The promoter is not particularly limited and may be appropriately selected depending on the purpose. In particular, when used as a counter electrode reactant, it is possible to use a compound that reversibly discolors by a known electrochemical redox reaction. In addition, when used as a redox mediator, in accordance with the properties of a compound that reversibly changes color by an electrochemical redox reaction, Journal of Synthetic Organic Chemistry, Vol. 43, No. 6 (“Organic synthesis using electric energy”). The known mediators described in “Special Issue” (1985) and the like can be appropriately selected and used.

Examples of preferred promoters that can be used in the present invention include the following compounds.
1) N-oxyl derivatives typified by TEMPO, N-hydroxyphthalimide derivatives, hydroxamic acid derivatives, etc. Compounds having an N—O bond 2) Allyloxy free radicals introduced with bulky substituents at the 0-position, such as galvinoxyl 3) Ferrocene etc., metallocene derivatives 4) benzyl (diphenylethanedione) derivatives 5) tetrazolium salts / formazan derivatives 6) azine compounds such as phenazine, phenothiazine, phenoxazine, acridine 7) pyridinium compounds such as viologen and others, benzoquinone Derivatives, hydrazyl free radical compounds such as verdazil, thiazyl free radical compounds, hydrazone derivatives, phenylenediamine derivatives, triallylamine derivatives, tetrathiafulvalene derivatives, tetracyanoquinodimethane derivatives, thianthrene derivatives A conductor or the like can also be used as a promoter.

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

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

N-oxyl (also called nitroxide radical) is an oxygen-centered radical generated by radically cleaving the oxygen-hydrogen bond of hydroxylamine. The nitroxide radical is known to have two reversible redox pairs as shown in the following scheme. The nitroxide radical becomes an oxoammonium cation by one-electron oxidation, and this is reduced to regenerate the radical. The nitroxide radical becomes an aminoxy anion by one-electron reduction, which is oxidized to regenerate the radical. Therefore, the nitroxide radical can function as a p-type counter electrode reactant or an n-type counter electrode reactant. In addition, the oxoammonium cation has a high oxidation ability and can function as a mediator because it can oxidize leuco dye and the like.

The N-oxyl derivative 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. It is done. The N-oxyl derivative may be added in the form of an N-oxyl radical, or in the form of an N-hydroxy compound, and further in the form of an oxoammonium cation.

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

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

Next, N-hydroxyphthalimide derivatives, hydroxamic acid derivatives, etc. will be described. As shown in the following scheme, phthalimide N-oxyl (PINO) generated by electrode oxidation of N-hydroxyphthalimide (NHPI) oxidizes a secondary alcohol to form a ketone. That is, it has been reported that NHPI functions as an oxidation mediator (Chem. Commun., 1983, 479). As can be seen from this example, it is understood that the redox couple of NHPI / PINO functions as a counter electrode reactant or mediator also in the display element of the present invention. As with NHPI, hydroxamic acid derivatives and trihydroxyimino cyanuric acid (THICA) can also be used as promoters.

When the display element of the present invention is produced using these compounds, it is preferably added in the state of N—OH. After the display element is manufactured in the N—OH state, radicals are generated by driving the display element and performing oxidation.

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

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

Further, promoters obtained by polymerizing these are disclosed in, for example, JP-A Nos. 2004-227946, 2004-228008, 2006-73240, 2007-35375, 2007-70384, 2007-184227, 2007. -298713 can be synthesized with reference to each publication.

In the formula, Rm ₁₁ and Rm ₁₂ are each independently an optionally substituted aliphatic hydrocarbon group, aromatic hydrocarbon group, heterocyclic group, or>C═O,>C═S,> C═N. And represents a group bonded to a nitrogen atom via —Rm ₁₃ . Rm ₁₃ represents a hydrogen atom or an aliphatic hydrocarbon group optionally having substituent, an aromatic hydrocarbon group or a heterocyclic group. Rm ₁₁ and Rm ₁₂ may be connected to each other to form a cyclic structure.

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

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

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

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

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

These aliphatic hydrocarbon group, aromatic hydrocarbon group and heterocyclic group have the same meanings as the respective groups in the general formula (M1).

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

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

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

These aliphatic hydrocarbon group, aromatic hydrocarbon group, and heterocyclic group are synonymous with the respective groups in formula (M1). In the general formula (M3), Rm ₃₂ is preferably an aromatic hydrocarbon group, particularly preferably a phenyl group which may have a substituent. The substituent on the phenyl group is preferably an electron-withdrawing group such as a cyano group, an alkoxycarbonyl group, or a trifluoromethyl group. Rm ₃₁ is preferably a phenyl group or an aliphatic hydrocarbon group directly bonded to a carbonyl carbon atom, particularly preferably a branched alkyl group or a cycloalkyl group. Note that the compound represented by the general formula (M3) is preferably added in the state of N—OH to manufacture a display element.

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

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

In the general formula (M4), Z ₂ represents an atomic group necessary for forming a cyclic structure, and preferably forms a 5-membered ring or a 6-membered ring. Z ₂ may further have a substituent, and examples of the substituent include the substituents exemplified in Formula (M1). Z ₂ may be a condensed ring. Note that the compound represented by the general formula (M4) is preferably added in the state of N—OH to manufacture a display element.

In the present invention, it is one of the preferred embodiments that the N-oxyl derivative according to the present invention is a compound represented by the general formula (M4).

In the formula, Rm ₅₁ to Rm ₅₅ each independently represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic group which may have a substituent. These aliphatic hydrocarbon group, aromatic hydrocarbon group, and heterocyclic group are synonymous with the respective groups in formula (M1).

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

In the present invention, it is one of the preferred embodiments that the N-oxyl derivative according to the present invention is a compound represented by the general formula (M5).

In the formula, Rm ₆₁ and Rm ₆₂ each independently represent a hydrogen atom or an aliphatic hydrocarbon group which may have a substituent, and Z ₃ to Z ₅ each represents an atomic group necessary for forming a cyclic structure. , N represents 0 or 1. Rm ₆₁ and Rm ₆₂ are preferably a hydrogen atom or a linear alkyl group having 4 or less carbon atoms, and at least one of Rm ₆₁ and Rm ₆₂ is preferably a hydrogen atom.

Z ₃ to Z ₅ each represents an atomic group necessary for forming a cyclic structure (for example, carbon, nitrogen, oxygen, sulfur, etc.), and each preferably forms a 5-membered ring or a 6-membered ring. Z ₃ to Z ₅ may further have a substituent. n represents 0 or 1, but when n = 0, the general formula (6) represents a bicyclo compound, and when n = 1, a tricyclo compound.

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

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

"Electrolytes"
The electrolyte referred to 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 a narrowly defined electrolyte). In the description of the present invention, the electrolyte is defined as a narrowly defined electrolyte. A mixture containing other metals, compounds and the like regardless of non-electrolytes is referred to as an electrolyte (broadly defined electrolyte).

(Electrolyte solvent)
The present invention is characterized in that an aprotic polar solvent is used as a solvent for the electrolyte. Examples of the aprotic polar solvent include dimethyl carbonate, diethyl carbonate, propylene carbonate, ethylene carbonate, butyrolactan, diethyl ether, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, dioxolane, Methyldioxolane, acetonitrile, benzonitrile, nitrobenzene, N, N-dimethylformamide, N, N-diethylformamide, sulfooxide, dimethylsulfoxide dimethylsulfone, tetramethylenesulfone, sulfolane, N-methyl-2-oxdorinoline and these Mixtures can be used.

The boiling point of the electrolyte solvent is not particularly limited, but is preferably a high boiling point and preferably has a boiling point of 200 ° C. or higher from the viewpoint of preventing volatility and production.

In the present invention, particularly preferably used solvents are compounds represented by the following general formulas (S1) and (S2).

(Compounds represented by formulas (S1) and (S2))
In the display element of 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.

First, the details of the compound represented by the general formula (S1) will be described.

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 the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, a dodecyl group, a tridecyl group, a tetradecyl group, and a pentadecyl group. Examples of the cycloalkyl group such as phenyl group, naphthyl group, etc. include, for example, cyclopentyl group, cyclohexyl group, etc., alkoxyalkyl groups, such as β-methoxyethyl group, γ-methoxypropyl group, etc. 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 the general formula (S2) will be described.

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

Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, a dodecyl group, a tridecyl group, a tetradecyl group, and a pentadecyl group. Examples of the cycloalkyl group such as phenyl group, naphthyl group, etc. include, for example, cyclopentyl group, cyclohexyl group, etc., alkoxyalkyl groups, such as β-methoxyethyl group, γ-methoxypropyl group, etc. 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.

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

In the present invention, particularly preferably used solvents are the compounds represented by the above general formulas (S1) and (S2). 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. A solvent can be used in combination. Specific examples of the other solvent include 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 Recall monobutyl 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.

Further, examples of the solvent that can be used in the present invention include J. 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 Electrolytes Handbook”, Vol. 1, Academic Press (1972).

(Supporting electrolyte)
As the supporting electrolyte used in the present invention, salts, acids and alkalis which are usually used in the field of electrochemistry or the field of batteries can be used.

The salts are not particularly limited, 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 ⁻ and PF. Li salt, Na salt, or K salt having a counter anion selected from ₆ ⁻ , AsF ₆ ⁻ , CH ₃ COO ⁻ , CH ₃ (C ₆ H 4) SO ₃ ⁻ , and (C ₂ F ₅ SO ₂ ) ₃ C ⁻ The metal salt is mentioned.

Also, halogen ions, SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ ⁻ , PF ₆ ⁻ , AsF ₆ ⁻ , CH _A quaternary ammonium salt having a counter anion selected from ₃ COO ⁻ , CH ₃ (C ₆ H ₄ ) SO ₃ ⁻ , and (C ₂ F ₅ SO ₂ ) ₃ C ⁻ , specifically, (CH ₃ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ NBF ₄ , (n-C ₄ H ₉ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ NBr, (C ₂ H ₅ ) ₄ NClO ₄ , (n-C ₄ H ₉ ) ₄ NClO ₄ , CH ₃ (C ₂ H ₅ ) ₃ NBF ₄ , (CH ₃ ) ₂ (C ₂ H ₅ ) ₂ NBF ₄ , (CH ₃ ) ₄ NSO ₃ CF ₃ , (C ₂ H ₅ ) ₄ NSO ₃ CF ₃ , (nC ₄ H ₉ ) ₄ NSO ₃ CF ₃ ,

Etc.

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

As the supporting electrolyte of the present invention, a cyclic quaternary ammonium salt is preferable, and a quaternary spiro ammonium salt is particularly preferable. As the counter anion, ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ and PF ₆ ⁻ are preferable, and BF ₄ ⁻ is particularly preferable.

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

In the present invention, in addition to the electrolyte solvent and the supporting electrolyte, the following compounds may be added.

[Metal salt compounds]
The metal salt compound according to the present invention is a salt containing a metal species that can be dissolved and precipitated by driving the pair of opposed electrodes on at least one electrode on the pair of opposed electrodes. Any compound may be used as long as it is present. Preferred metal species are silver, bismuth, copper, nickel, iron, chromium, zinc and the like, particularly preferred are silver and bismuth, and silver is most preferred.

(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.

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

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

Formula (1): 0 ≦ [X] / [Metal] ≦ 0.1
The halogen atom as used in the field of this invention means an iodine atom, a chlorine atom, a bromine atom, and a fluorine atom. When [X] / [Metal] is greater than 0.1, X ⁻ → X ₂ is generated during the metal redox reaction, and X ₂ easily cross-oxidizes with the deposited metal to dissolve the deposited metal. Therefore, the molar concentration of the halogen atom is preferably as low as possible with respect 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.

(Silver salt solvent)
In the present invention, the electrolyte preferably contains a compound represented by the following general formula (G1) or general formula (G2) in order to promote dissolution and precipitation of metal salts (particularly silver salts).

The compounds represented by the general formulas (G1) and (G2) are compounds that promote the solubilization of silver in the electrolyte in order to cause dissolution and precipitation of silver in the present invention. In general, in order to cause dissolution and precipitation of silver, it is necessary to solubilize silver in an 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 They are characterized by little influence on coexisting compounds and high solubility in solvents.

(Compound represented by General Formula (G1))
Formula (G1) Rg ₁₁ -S-Rg ₁₂
In the formula, Rg ₁₁ and Rg ₁₂ each represent a substituted or unsubstituted hydrocarbon group. In addition, 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. .

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, specific examples of the compound represented by the general formula (G1) according to the present invention will be shown, but the present invention is not limited 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 (HN =) CSCH ₂ CH ₂ SC (NH) NH ₂ .2HBr
G1-32: H ₂ N (HN =) CSCH ₂ CH ₂ OCH ₂ CH ₂ OCH ₂ CH ₂ SC (NH) NH ₂ .2HCl
G1-33: H ₂ N (HN =) 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 general formula (G2))

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 may be connected to each other to form a condensed ring. It may be formed.

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, etc.) 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.), A reeloxy group (for example, phenoxy), an alkylthio group (for example, methylthio, ethylthio, butylthio, etc.), an arylthio group (for example, phenylthio group, tolylthio group, etc.), an alkylcarbamoyl group (for example, methylcarbamoyl, dimethylcarbamoyl, ethylcarbamoyl, Diethylcarbamoyl, dibutylcarbamoyl, piperidylcarbamoyl, morpholylcarbamoyl, etc.), arylcarbamoyl groups (eg, phenylcarbamoyl, methylphenylcarbamoyl, ethylphenylcarbamoyl, benzylphenylcarbamoyl, etc.), alkylsulfamoyl groups (eg, methylsulfamoyl) , Dimethylsulfamoyl, ethylsulfamoyl, diethylsulfamoyl, dibutylsulfamoyl, piperidylsulfamo , Morpholylsulfamoyl, etc.), arylsulfamoyl groups (eg, phenylsulfamoyl, methylphenylsulfamoyl, ethylphenylsulfamoyl, benzylphenylsulfamoyl, etc.), alkylsulfonyl groups (eg, methane) Sulfonyl group, ethanesulfonyl group, etc.), arylsulfonyl group (eg, phenylsulfonyl, 4-chlorophenylsulfonyl, p-toluenesulfonyl, etc.) alkoxycarbonyl group (eg, methoxycarbonyl, ethoxycarbonyl, butoxycarbonyl, etc.), aryloxycarbonyl group (For example, phenoxycarbonyl), alkylcarbonyl groups (for example, acetyl, propionyl, butyroyl, etc.), arylcarbonyl groups (for example, benzoyl group, alkylbenzoyl groups, etc.), a Siloxy 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 and the like. These substituents further include those having a substituent.

Next, preferred specific examples of the compound represented by the general formula (G2) are shown, but the present 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 objective effects of the present invention can be exhibited.

《White scattering material》
In the present invention, from the viewpoint of further increasing the display contrast and the white display reflectance, it is preferable to contain a white scattering material, and a porous white scattering layer may be formed and present.

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

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 and other inorganic compounds, polyethylene, polystyrene, acrylic resin, ionomer, ethylene-vinyl acetate copolymer resin, benzoguanamine resin, urea-formalin resin Organic compounds such as melamine-formalin resin and polyamide resin 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 coloring prevention at high temperature and the reflectance of the 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 water-soluble polymers and polymers dispersed in water-based solvents.

Examples of water-soluble compounds include proteins such as gelatin and gelatin derivatives, cellulose derivatives, natural compounds such as polysaccharides such as starch, gum arabic, dextran, pullulan and carrageenan, polyvinyl alcohol, polyvinyl pyrrolidone, acrylamide polymers and their 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. Further, 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. Homopolymers of vinyl monomers having the described superabsorbent polymers, ie —COOM or —SO ₃ M (M is a hydrogen atom or an alkali metal), or these vinyl monomers or other vinyl monomers (for example, sodium methacrylate, methacryl Copolymers with ammonium acid, 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 water-based solvents include natural rubber latex, styrene butadiene rubber, butadiene rubber, nitrile rubber, chloroprene rubber, isoprene rubber and other latexes, 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, the water-based polyurethane resin described in JP-A-10-76621 is preferably used.

In the present invention, “substantially insoluble in the solvent of the electrolyte” is defined as a state where the amount of electrolyte dissolved in 1 kg of the solvent is 0 to 10 g 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, the water admixture 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 by volume, more preferably 0.3 to 0.05.

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 pair of opposed electrodes of the display element, but at least of the pair of opposed electrodes. It is preferable to apply on one electrode surface. 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.

The 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 a pair of opposing electrodes, and a potential difference can be applied between the opposing pair of electrodes to cause a dissolution and precipitation reaction of silver. A penetration state that can be moved between.

In the display element of the present invention, it is desirable to carry out a curing reaction of the aqueous 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, US Pat. No. 4,678,739, column 41, 4,791,042, JP-A-59-116655, and 62-245261. Nos. 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 aqueous compound. It is also possible to adjust the humidity during the heat treatment or 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.

The porous film can be formed by a sintering method (fusion method) (using fine particles or inorganic particles added to a binder or the like and partially fused to make use of pores formed between the particles), extraction method ( After forming a constituent layer with a solvent-soluble organic or inorganic substance and a binder that does not dissolve in the solvent, the organic or inorganic substance is dissolved with the solvent to obtain pores), and the polymer is heated or degassed Well-known formation methods such as foaming method for foaming, phase change method for phase separation of polymer mixture by manipulating good solvent and poor solvent, and radiation irradiation method for forming pores by radiating various radiations 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).

The types of compounds shown in these three research disclosures and their locations are listed in Table 1 below.

"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-62-1117708, JP-A-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 reflection 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. Further, the support 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.

Sealing agent is for sealing so that it does not leak to the 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 appropriately 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 to the display area of the display element is 1 to 40%, a practically sufficient strength as a display element can be obtained.

A spacer may be provided between the pair of substrates for uniformly maintaining a gap between the substrates. Examples of the spacer include a sphere made of resin or inorganic oxide. Further, a fixed spacer having a surface coated with a thermoplastic resin is also preferably used. In order to hold the gap between the substrates uniformly, only the columnar structure may be provided, but both the spacer and the columnar structure may be provided, or instead of the columnar structure, only the spacer is used as the space holding member. May be used. The diameter of the spacer is equal to or less than the height of the columnar structure, preferably equal to the height. When the columnar structure is not formed, the diameter of the spacer corresponds to the thickness of the cell gap.

<< Display element driving method >>
The method for controlling the transparent state and the colored state of the display element of the present invention is preferably determined on the basis of the redox potential of the EC dye and the silver ion precipitation overvoltage.

For example, in the case of a display element having a compound represented by the general formula (L) and a silver compound between a pair of electrodes facing each other, 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, the compound represented by the general formula (L) is oxidized and colored other than black 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 reduced to a white state by applying a voltage between the oxidation-reduction 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. The method of melt | dissolving and decoloring silver which precipitated by applying the voltage between is mentioned.

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. I mean. 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 advantages 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.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

Example 1
<< Production of display element >>
[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.

(Preparation of electrode A3)
The following ink liquid a1 was applied onto the electrode A2 at 120 dpi with an inkjet apparatus having a piezo-type head, to produce an electrode A3. In the present invention, dpi represents the number of dots per 2.54 cm.

(Production of electrode A4)
An electrode A4 was produced in the same manner as the electrode A3 except that the ink liquid a1 was changed to the ink liquid a2.

<Preparation of ink liquid a1>
Exemplified EC dye (L1) was dissolved in acetonitrile / ethanol mixed solvent (1/1) to prepare a concentration of 3 mmol / L.

<Preparation of ink liquid a2>
Exemplified EC dye Ot1 was dissolved in acetonitrile / ethanol mixed solvent (1/1) to prepare a concentration of 3 mmol / L.

[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. To obtain a gold-nickel electrode (electrode B1) having a depth of 0.05 μm substituted with gold from the electrode surface.

(Preparation of electrolyte)
(Preparation of electrolytes 1-1 to 1-15)
To 2.5 g of various solvents shown in Table 2 below, 0.025 g of tetrafluoroborate spiro (1,1 ′)-bipyrrolidinium (SBP) as a supporting electrolyte, various gelling agents in amounts shown in Table 2, and exemplified promoter 0 .05 g was added and dissolved by heating to prepare electrolytes 1-1 to 1-15.

[Production of display element]
(Preparation of display element 1-1)
20% by mass of Titanium Dioxide CR-90 manufactured by Ishihara Sangyo Co., Ltd. is added to an isopropanol solution containing 2% by mass of polyvinyl alcohol (average polymerization degree 3500, saponification degree 87%) to prepare a mixed liquid dispersed with an ultrasonic disperser. did.

Next, on the periphery of the electrode B1 bordered with an olefin-based sealant containing a glass spherical bead spacer having an average particle size of 40 μm as a volume fraction of 10%, the film thickness after drying the admixture is 20 μm. It applied so that it might become. Thereafter, the mixture was dried at 15 ° C. for 30 minutes to evaporate the solvent, and then dried in an atmosphere at 45 ° C. for 1 hour. After sprinkling glass spherical bead-shaped spacers having an average particle diameter of 20 μm on the obtained titanium dioxide layer, the electrodes B1 and A3 were bonded together and heated and pressed to produce empty cells.

The electrolyte solution 1-1 kept at 50 ° C. was injected into the empty cell under reduced pressure, 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 1-15)
Display elements 1-2 to 1-15 were obtained in the same manner as in the production of the display element 1-1 except that the electrolytic solution 1-1 was changed from the electrolytic solution 1-2 to the electrolytic solution 1-15.

(Preparation of display element 1-16)
A display element 1-16 was obtained in the same manner as in the production of the display element 1-1 except that the electrolytic solution 1-1 was changed to the electrolytic solution 1-5 and the electrode A3 was changed to the electrode A4.

(Preparation of display element 1-17)
A display element 1-17 was obtained in the same manner as in the production of the display element 1-1 except that the electrolytic solution 1-1 was changed to the electrolytic solution 1-2 and the electrode A3 was changed to the electrode A4.

<< Evaluation of gelation state >>
Each electrolyte solution was heated and added to a sample bottle having a diameter of 1 cm, then cooled to room temperature, and the state where the sample bottle was turned upside down was visually evaluated according to the following criteria.

○: Even if the sample bottle is tapped, it does not flow down. Δ: When the sample bottle is tapped, it flows down.

<< Evaluation of display element >>
[Evaluation of reflectance stability when driven repeatedly]
(Evaluation of display element 1-1)
Visible when both electrodes of the display element are connected to both terminals of a constant voltage power supply, and a voltage of −1.5 V is applied for 1.5 seconds, and then a voltage of +1.5 V is applied for 1 second to cause color display. The reflectance at the maximum absorption wavelength in the light region 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 _COLOR1 = | R _ave1 −R _ave2 | was used as an index of stability of reflectance when ΔR _COLOR1 was repeatedly driven. Here, the smaller the value of ΔR _COLOR1 , the _better the stability of the reflectance when it is repeatedly driven.

(Evaluation of display element 1-2 to display element 1-17)
Display elements 1-2 to 1-17 were evaluated in the same manner as display element 1-1 except that the voltage applied to the display element was changed to the values shown in Table 3.

[Evaluation of display element uniformity (unevenness)]
After the number of repetitions of the evaluation of the stability of the reflectance when repeatedly driven was extended to 20,000 times, the state of unevenness of the display element was visually evaluated according to the following criteria.

○: A substantially uniform color development / decoloration state is maintained. Δ: Discoloration or density unevenness is observed. ×: Discoloration or density unevenness is remarkable. XX: The element does not drive (the density does not change when voltage is applied).
Table 3 shows the evaluation results of the respective display elements obtained as described above.

As can be seen from Table 3, the gelling agents of the present invention (compounds of general formulas (GI) and (GII)) are found to have a stronger gelling ability than the comparative gelling agents.

Also, comparative display element No. In 1-5, 1-10, 1-13, 1-14, and 1-16, a sufficient density change does not occur when a voltage of ± 1.5 V is applied. The change was also great. On the other hand, the comparative display element no. Except for being a liquid, 1-15 was driven at a low voltage and had a favorable performance with a small change in reflectance. However, when the number of times of repeated driving was increased, the driving speed gradually decreased and eventually The device has stopped driving.

On the other hand, it can be seen that the display element satisfying the configuration of the present invention has improved reflectance stability, display unevenness, and the like even when it is repeatedly driven.

Example 2
<< Production of display element >>
As the display electrode and the counter electrode, the electrode A3 and the electrode B1 used in Example 1 were used, respectively.

(Preparation of electrolyte)
(Preparation of electrolytes 2-1 to 2-12)
0.025 g of tetrafluoroborate spiro (1,1 ')-bipyrrolidinium (SBP) as a supporting electrolyte, 2.5 g of various solvents shown in Table 4 below, a metal that is reversibly dissolved and precipitated by an electrochemical redox reaction As a salt compound, 0.1 g of silver p-toluenesulfonate, 0.2 g of Exemplified Compound G1-3 as a silver salt solvent, various gelling agents in the amounts shown in Table 4, and 0.05 g of an exemplary promoter are added and dissolved by heating. Electrolyte solutions 2-1 to 2-12 were prepared.

Display elements 2-1 to 2-12 were fabricated in the same manner as in the method described in Example 1.

<< 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 a voltage of -1.5 V for 1.5 seconds and display in gray, and a wavelength of 550 nm and a voltage of +1.5 V are 1. The reflectance at the maximum absorption wavelength in the visible light region when applied and colored for 5 seconds was measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing. Driven a total of 10 times under similar driving conditions, 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 BK2 = | R ave3 -R ave5} |, ΔR COLOR2 = | R ave4 -R ave6 | a, and as an index of the stability of the reflectance when driven repeatedly R _BK and R _COLOR2. Here, the smaller the values of ΔR _BK2 and ΔR _COLOR2 , the _better the stability of the reflectance when repeatedly driven.

Evaluation of the gelled state and evaluation of the uniformity (unevenness) of the display element were performed by the same method and standard as in Example 1.

Table 5 shows the evaluation results of each electrolytic solution and display element obtained as described above.

As is apparent from the results shown in Table 5, it can be seen that the display element satisfying the configuration of the present invention has improved reflectance stability, display unevenness, and the like when it is repeatedly driven as compared with the comparative example. .

Example 3
<< Production of display element >>
As the display electrode and the counter electrode, the electrode A1 and the electrode B1 used in Example 1 were used, respectively.

(Preparation of electrolyte)
(Preparation of electrolytes 3-1 to 3-14)
To 2.5 g of various solvents shown in Table 6 below, 0.025 g of tetrafluoroborate spiro (1,1 ′)-bipyrrolidinium (SBP) as a supporting electrolyte, various gelling agents in amounts shown in Table 6, and exemplified promoter 0 .05 g was added and dissolved by heating to prepare electrolytic solutions 3-1 to 3-14.

(Preparation of display element 3-1)
20% by mass of Titanium Dioxide CR-90 manufactured by Ishihara Sangyo Co., Ltd. is added to an isopropanol solution containing 2% by mass of polyvinyl alcohol (average polymerization degree 3500, saponification degree 87%) to prepare a mixed liquid dispersed with an ultrasonic disperser. did.

Next, on the periphery of the electrode B1 bordered with an olefin-based sealant containing a glass spherical bead spacer having an average particle size of 40 μm as a volume fraction of 10%, the film thickness after drying the admixture is 20 μm. It applied so that it might become. Thereafter, the mixture was dried at 15 ° C. for 30 minutes to evaporate the solvent, and then 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 3-1 kept at 50 ° C. was injected into the empty cell under reduced pressure, and the injection port was sealed with an epoxy-based ultraviolet curable resin to produce a display element 3-1.

(Preparation of display elements 3-2 to 3-14)
Display elements 3-2 to 1-14 were obtained in the same manner as in the production of the display element 3-1, except that the electrolytic solution 3-1 was changed from the electrolytic solution 3-2 to the electrolytic solution 3-14.

<< Evaluation of display element >>
[Evaluation of reflectance stability when driven repeatedly]
Wavelength when both electrodes of the display element are connected to both terminals of a constant voltage power supply and a voltage of +1.5 V is applied for 1.5 seconds and then a voltage of -1.5 V is applied for 1 second to display gray The reflectance at 550 nm was measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing. Under the same driving conditions, driving was carried out 10 times in total, and the average value of the obtained reflectance was _Rave7 . Further, after driving repeatedly 10,000 times, _Rave8 was obtained by the same method. _{ΔR COLOR1 = | R ave7 -R ave8} | a, and as an index of the stability of the reflectance when was repeatedly drive the [Delta] R _BK3. Here, the smaller the value of ΔR _BK3, the better the stability of the reflectance when it is repeatedly driven.

Evaluation of gelation state and evaluation of display element uniformity (unevenness) were performed by the same method and standard as in Example 1. Table 7 shows the evaluation results of the electrolytic solutions and display elements obtained as described above.

As is apparent from the results shown in Table 7, it can be seen that the display element satisfying the configuration of the present invention has improved reflectance stability, display unevenness, and the like when it is repeatedly driven as compared with the comparative example. .

Claims (9)

1. An electrolyte, a compound that changes color reversibly by an electrochemical oxidation-reduction reaction, and an auxiliary compound that can be oxidized / reduced to promote the electrochemical oxidation-reduction reaction are contained between a pair of opposed electrodes. In the display element that performs white display and color display by driving the electrode, the solvent of the electrolyte is an aprotic polar solvent and includes a compound represented by the following general formula (GI) Display element.
   General formula (GI) Rf-LX-Ar-Ball
   (In the formula, Rf represents a perfluoroalkyl group, L represents an alkylene group which may have a substituent, or a simple bond. X represents a sulfur atom, an oxygen atom or N—Rn. Rn represents a hydrogen atom. Or represents a substituent, Ar represents a divalent aromatic group which may have a substituent, and Ball represents a hydrophobic group having 5 or more carbon atoms.)
2. The display device according to claim 1, wherein the compound represented by the general formula (GI) is a compound represented by the following general formula (GII).
   General formula (GII) Rf-L—X—Ar—Y—R
   (In the formula, Rf represents a perfluoroalkyl group, L represents an alkylene group which may have a substituent, or a simple bond. X represents a sulfur atom, an oxygen atom or N—Rn. Rn represents a hydrogen atom. Alternatively, Ar represents a divalent aromatic group which may have a substituent, Y represents a linking group that binds to Ar by an oxygen atom, a sulfur atom, or a nitrogen atom, and connects Ar and R. R represents an aliphatic group having 5 or more carbon atoms which may have a substituent.
3. 3. The display element according to claim 1, wherein the compound that reversibly changes color by an electrochemical oxidation-reduction reaction is an electrochromic compound.
4. The display element according to claim 3, wherein the electrochromic compound is represented by the following general formula (L).
   

   

   
   (Wherein 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. 5. The display element according to claim 3, wherein the auxiliary compound capable of being oxidized and reduced that promotes an electrochemical reaction of the electrochromic compound is an N-oxyl derivative.
6. 6. The display element according to claim 1, wherein the compound that reversibly changes color by the electrochemical oxidation-reduction reaction is a metal salt compound.
7. The display element according to claim 6, wherein the metal salt compound is a silver salt compound.
8. The compound represented by the following general formula (G1) or the compound represented by the general formula (G2) is contained between the pair of facing electrodes, according to claim 6 or 7, The display element as described.
   Formula (G1) Rg ₁₁ -S-Rg ₁₂
   (Wherein 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 atoms, halogen atoms are substituted. And Rg ₁₁ and Rg ₁₂ may be linked to each other to form 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, and Rg ₂₁ represents a substituent. In the case where n is 2 or more, each Rg ₂₁ may be the same or different, and may be linked to each other to form a condensed ring.
9. The multicolor display of three or more colors of substantially black display, white display, and color display other than black is performed by driving the pair of opposed electrodes. The display element according to any one of the above.