WO2011096298A1 - Display element - Google Patents

Abstract

Disclosed is a display element which is capable of obtaining a good contrast ratio with a less amount of a color developing colorant, namely a display element which is capable of obtaining a good contrast ratio with low power consumption. Specifically disclosed is a display element which comprises a color development space between at least a pair of electrodes that face each other. The display element is characterized in that the color development space satisfies the following formulae (1) and (2). Formula (1): n₂·d₂ ≤ 90 or n₂·d₂ ≥ 185 Formula (2): 100 ≤ n₁·d₁ ≤ 175 (In the formulae, n₁ and d₁ respectively represent the refractive index n₁ and the thickness d₁ (nm) of the color development space when the display element has colored (or black) display; and n₂ and d₂ respectively represent the refractive index n₂ and the thickness d₂ (nm) of the color development space when the display element has white display.)

Description

Display element

The present invention relates to a display element, and more particularly to a display element with reduced power consumption.

In recent years, with the increase in the operating speed of personal computers, the spread of network infrastructure, the increase in capacity and price of data storage, information such as documents and images that have been provided as printed materials on paper has become easier. Opportunities for obtaining and browsing electronic information are increasing.

As a means for browsing such electronic information, conventional liquid crystal displays and CRTs, and in recent years, light-emitting types such as organic electroluminescence displays are mainly used. In particular, when the electronic information is document information, it is necessary to keep an eye on the browsing means for a relatively long time. These actions are hardly human-friendly means. It is known that the user is tired, inconvenient to carry, limited reading posture, needs to be in line with the still screen, and consumes power when reading for a long time.

As a display means to compensate for these drawbacks, a reflection type display using so-called "memory" that uses external light and does not consume power for image retention is known. However, it has sufficient performance for the following reasons. It is hard to say that it is demonstrating.

That is, the method using a polarizing plate such as a reflective liquid crystal has a low reflectance of about 40%, which makes it difficult to display white, and it is difficult to say that many of the manufacturing methods used to manufacture the constituent members are simple. In addition, the polymer dispersed liquid crystal requires a high voltage and utilizes the difference in refractive index between organic substances, so that the resulting image has insufficient contrast. In addition, the polymer network type liquid crystal has problems such as a high driving voltage and a need for a complicated TFT circuit in order to improve 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 aggregation of electrophoretic particles.

On the other hand, an electrochromic display element can be driven at a low voltage with a simple member structure, and can display a relatively bright white display or a black and white display with a high contrast, and is expected to be applied to electronic paper, electronic books, and the like. Various methods are disclosed (for example, refer to Patent Documents 1 and 2).

However, the electrochromic display element, like the electrophoretic display element, performs colored display by light absorption by the dye, and therefore, in order to obtain a sufficient contrast ratio, the thickness of the colored material is required. The occupied volume ratio will increase. For this reason, there are problems such that the drive voltage becomes high and viewing angle dependency occurs, so that high-resolution display cannot be performed. Therefore, there has been a demand for a display element that efficiently obtains a high contrast ratio with a smaller amount of coloring material.

WO2004 / 068231 Specification WO 2004/066773 specification

The present invention has been made in view of the above problems, and an object of the present invention is to provide a display element that can obtain a good contrast ratio with a smaller amount of coloring material, that is, a good contrast ratio with low power consumption. There is to do.

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

1. A display element having a color space between at least a pair of opposing electrodes, wherein the color space satisfies the following formulas (1) and (2).

Formula (1)
n ₂ · d ₂ ≦ 90 or n ₂ · d ₂ ≧ 185
Formula (2)
100 ≦ n ₁ · d ₁ ≦ 175
[Where n ₁ and d ₁ are the refractive index n ₁ and thickness d ₁ (nm) of the coloring space when the display element is colored (or black), respectively, and n ₂ and d ₂ are The refractive index n ₂ and the thickness d ₂ (nm) of the coloring space in the white display state. ]
2. 2. The display element according to 1, wherein an electrolyte is further contained between the pair of opposed electrodes, and the coloring space contains an electrochromic compound.

3. 3. The display element according to 2 above, wherein the electrochromic compound is an organic dye.

4. 4. The display element according to 2 or 3, wherein the electrochromic compound is a compound represented by the following general formula (L).

[Wherein, Rl ₁ represents a substituted or unsubstituted aryl group, and Rl ₂ and Rl ₃ each represent a hydrogen atom or a substituent. X represents> N—Rl ₄ , an oxygen atom or a sulfur atom, and Rl ₄ represents a hydrogen atom or a substituent. ]
5. 5. The display element according to 4 above, wherein the compound represented by the general formula (L) is a compound represented by the following general formula (L2).

Wherein Rl ₂₁ and Rl ₂₂ each represents an aliphatic group, an aliphatic oxy group, an acylamino group, a carbamoyl group, an acyl group, a sulfonamide group or a sulfamoyl group, and Rl ₂₃ represents an aromatic group or an aromatic heterocyclic group Rl ₂₄ represents a hydrogen atom, an aliphatic group, an aromatic group or an aromatic heterocyclic group, and Rl ₂₅ represents a hydrogen atom, an aliphatic group, an aromatic group or an acyl group. ]
6). 6. The display element according to any one of 2 to 5, wherein the electrochromic compound is fixed to a transparent porous electrode.

7. 7. The display element according to any one of 2 to 6, wherein a metal salt compound is contained in the electrolyte, and black display and white display are performed by a driving operation of the opposing electrode.

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

9. 9. The display element as described in 7 or 8 above, wherein the electrolyte further contains a compound represented by the following general formula (G-1) or (G-2).

General formula (G-1)
Rg ₁₁ -S-Rg ₁₂
[Wherein, Rg ₁₁ and Rg ₁₂ each represent a substituted or unsubstituted hydrocarbon group. Further, these hydrocarbon groups may contain one or more nitrogen atom, oxygen atom, phosphorus atom, sulfur atom or halogen atom, and Rg ₁₁ and Rg ₁₂ may be connected to each other to take a cyclic structure. ]

[Wherein, 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 hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkylcarbonamide group, an arylcarbonamide group, an alkylsulfonamide group, an arylsulfonamide group, an alkoxy group, an aryl Oxy group, alkylthio group, arylthio group, alkylcarbamoyl group, arylcarbamoyl group, carbamoyl group, alkylsulfamoyl group, arylsulfamoyl group, sulfamoyl group, cyano group, alkylsulfonyl group, arylsulfonyl group, alkoxycarbonyl group, Represents an aryloxycarbonyl group, an alkylcarbonyl group, an arylcarbonyl group, an acyloxy group, a carboxyl group, a carbonyl group, a sulfonyl group, an amino group, a hydroxy group or a heterocyclic group, and when n is 2 or more, Of Rg ₂₁ may be the same or different, and may be linked to each other to form a condensed ring. ]

According to the present invention, it has been possible to provide a display element that can obtain a good contrast ratio with a smaller amount of coloring material, that is, a good contrast ratio with low power consumption.

It is a schematic sectional drawing which shows an example of a structure of the display element of this invention.

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

As a result of intensive studies in view of the above problems, the present inventors have found that in a display element having a color development space between at least a pair of opposed electrodes, the color development space satisfies the expressions (1) and (2). As a result of the present invention, it has been found that a display element capable of obtaining a good contrast ratio with a smaller amount of colorant and low power consumption can be realized.

[Color development space]
The display element of the present invention is characterized in that, in a display element having a color development space between at least a pair of opposed electrodes, the color development space satisfies the following formulas (1) and (2).

Formula (1)
n ₂ · d ₂ ≦ 90 or n ₂ · d ₂ ≧ 185
Formula (2)
100 ≦ n ₁ · d ₁ ≦ 175
However, n ₁ and d ₁ are the refractive index n ₁ and the thickness d ₁ (nm) of the coloring space when the display element is in a colored (or black) display state, respectively, and n ₂ and d ₂ are the white display of the display element, respectively. The refractive index n ₂ and the thickness d ₂ (nm) of the coloring space in the state are represented.

[Basic structure of display element]
FIG. 1 shows an example of the structure of the display element of the present invention.

As shown in FIG. 1, in a typical display element 1 of the present invention, at least one pair of counter electrodes is provided. A transparent electrode 5 such as an ITO electrode is provided as one of the counter electrodes close to the display portion, and a conductive electrode 2 is provided on the other electrode. A color development space 4 is provided between the transparent electrode 5 and the conductive electrode 2. By applying positive and negative voltages between the counter electrodes, white display and colored display can be switched reversibly. The color development space 4 is a space in which visible light transmission and absorption can be reversibly switched by a voltage applied between a pair of counter electrodes. For example, an electrochromic layer containing an electrochromic compound, And a space on the electrode surface where metal ions in the electrolyte are deposited and dissolved. Moreover, it is preferable to provide the porous white scattering layer 3 containing a white scattering substance on the conductive electrode 2 from the viewpoint of further increasing the display contrast and the white display reflectance.

More specifically, when the phase of the visible light C reflected by the upper surface A and the lower surface B of the coloring space 4 is shifted by about ½ wavelength when the display element 1 is in a colored display state, the visible light is reflected by the interference of light. It is weakened and the color density is higher. Since the optical path difference between the reflected light C ′ from the upper surface A and the reflected light C ″ from the lower surface B of the coloring space 4 is 2n ₁ · d ₁ , the value of 2n ₁ · d ₁ is about ½ wavelength. The phase of the visible light C reflected by the upper surface A and the lower surface B of the coloring space 4 is shifted by a half wavelength, since the wavelength of the visible light C is about 400 nm to 700 nm, so that 100 ≦ n ₁ · d ₁ ≦ 175. The reflection of visible light is weakened by the interference of light and the coloring density in the colored display state is higher, while the reflection of visible light C is not weakened by the interference of light when the color development space 4 is in the visible light transmission absorption state. By doing so, the reflectance in the white display state can be increased, and the contrast ratio of the display element 1 can be increased, that is, the absorption of light due to light interference can be in the ultraviolet or infrared region. N ₂ · d ₂ ≦ 9 0, or n ₂ · d ₂ ≧ 185.

When the coloring space 4 contains an electrochromic compound as a colorant, the electrochromic compound undergoes coloring and decoloring by electrical oxidation and reduction. In this case, ions in the electrolytic solution are present in the coloring space 4 to compensate for the charge. In and out, the refractive index n of the coloring space changes, and at the same time, the thickness d (nm) of the coloring space also changes.

In the present invention, means for achieving the conditions defined by the formulas (1) and (2) according to the present invention are as follows.

As the first step, the type and addition amount of electrochromic dye constituting the color development space (volume ratio in the color development space), the existence form of the electrochromic dye in the color development space, and other members constituting the color development space, such as electrolysis By appropriately selecting the liquid, pigment, and porous fine particles, or by forming the electrode with a porous electrode and adjusting the type and amount of addition (volume ratio in the coloring space) of the electrochromic dye to be adsorbed thereto, the coloring space N ₁ and n ₂ are determined.

Next, as a second step, d ₁ and d ₂ are set so as to satisfy the expressions (1) and (2) according to the n ₁ and n ₂ of the coloring space set as described above.

When the metal salt compound is contained in the electrolyte and the metal is precipitated and dissolved in the coloring space, the refractive index of the coloring space changes with the deposition of the metal. In addition, the thickness of the coloring space may change. In any case, the effects of the present invention can be obtained by appropriately setting the refractive index and thickness of the color development space of the display element as described above.

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

〔Electrolytes〕
In the display element of the present invention, an electrolyte is preferably contained between a pair of opposed electrodes.

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

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

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 ⁻ , PF Li salt, Na 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 ⁻ K salt is mentioned.

Further, halogen ions, SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , PF ₆ ⁻ , AsF _{6 ^{-, CH 3 COO -, CH}} 3 (C 6 H 4) SO 3 -, and _{(C 2 F 5 SO 2)} 3 C - 4 quaternary ammonium salt having a counter anion selected from, specifically, (CH ₃ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ NBF ₄ , (n-C ₄ H ₉ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ NBr, (C ₂ H ₅ ) ₄ NClO ₄ , (n- C ₄ H ₉ ) ₄ NClO ₄ , CH ₃ (C ₂ H ₅ ) ₃ NBF ₄ , (CH ₃ ) ₂ (C ₂ H ₅ ) ₂ NBF ₄ , (CH ₃ ) ₄ NSO ₃ CF ₃ , (C ₂ H _{5) 4 NSO 3 CF 3,} (n-C 4 H 9 ₄ NSO ₃ CF _3,
Furthermore

Etc.

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

The amount of the supporting electrolyte used is arbitrary, but in general, the supporting electrolyte is present in the solvent as an upper limit of 20 mol / L or less, preferably 10 mol / L or less, more preferably 5 mol / L or less. The lower limit is usually 0.01 mol / L or more, preferably 0.05 mol / L or more, more preferably 0.1 mol / L or more.

In the case of a solid electrolyte, the following compounds exhibiting electronic conductivity and ionic conductivity can be contained in the electrolyte.

Vinyl fluoride polymer containing perfluorosulfonic acid, polythiophene, polyaniline, polypyrrole, triphenylamines, polyvinylcarbazoles, polymethylphenylsilanes, Cu ₂ S, Ag ₂ S, Cu ₂ Se, AgCrSe _2, etc. Fluorine-containing compounds such as chalcogenide, CaF ₂ , PbF ₂ , SrF ₂ , LaF ₃ , TlSn ₂ F ₅ , CeF ₃ , Li salts such as Li ₂ SO ₄ , Li ₄ SiO ₄ , Li ₃ PO ₄ , ZrO ₂ , CaO , Cd ₂ O ₃ , HfO ₂ , Y ₂ O ₃ , Nb ₂ O ₅ , WO ₃ , Bi ₂ O ₃ , AgBr, AgI, CuCl, CuBr, CuBr, CuI, LiI, LiBr, LiCl, LiAlCl ₄ , LiAlF ₄ , AgSBr, C ₅ H ₅ NHAg ₅ I ₆ , Rb ₄ Cu ₁₆ I Examples thereof include ₇ Cl ₁₃ , Rb ₃ Cu ₇ Cl ₁₀ , LiN, Li ₅ NI ₂ , and Li ₆ NBr ₃ .

[Electrochromic compound]
In the display element of the present invention, the color space formed between a pair of opposing electrodes preferably contains an electrochromic compound. Furthermore, the electrochromic compound is preferably an organic dye.

The electrochromic compound applicable to the present invention is not particularly limited as long as it has an action of coloring or decoloring by an electrochemical oxidation reaction and reduction reaction, and can be appropriately selected according to the purpose. Examples of such electrochromic 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, In addition to inorganic compounds such as zirconium nitride chloride, conductive polymer compounds and organic dyes are known.

In the display element of the present invention, a metal that can be decolored and colored by dissolution and precipitation by an electrochemical oxidation reaction and a reduction reaction can be used as the electrochromic compound according to the present invention. Preferable metal species include, for example, silver, bismuth, copper, nickel, iron, chromium, zinc, etc. Among them, silver and bismuth are more preferable.

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

Examples of organic dyes exhibiting electrochromic properties include pyridinium compounds such as viologen, azine dyes such as phenothiazine, styryl dyes, anthraquinone dyes, pyrazoline dyes, fluorane dyes, donor / acceptor compounds (for example, tetracyanoquino compounds) Dimethane, tetrathiafulvalene) and the like. In addition, compounds known as redox indicators and pH indicators can also be used.

When the electrochromic compounds are classified according to color change, they can be divided into the following three classes.

Class 1: An electrochromic compound that changes from one specific color to another by redox,
Class 2: An electrochromic compound that is substantially colorless in an oxidized state and exhibits a specific colored state that is a reduced state;
Class 3: An electrochromic compound that is substantially colorless in the reduced state and exhibits a specific colored state that is an oxidized state.

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

[Class 1 electrochromic compound]
A class 1 electrochromic compound is an electrochromic compound that changes from a specific color to another color by oxidation-reduction, and is a compound that can display two or more colors in its possible oxidation state.

As a compound 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 Ru ₂ O ₃ changes from yellow to dark green.

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 in an oxidation state to blue, green, and light yellow.

An electrochromic compound classified as class 1 is a single compound and has an advantage of being capable of multicolor display, but has a disadvantage that it cannot form a state that is substantially colorless.

[Class 2 electrochromic compounds]
Class 2 electrochromic 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) and the like.

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′-biphenyl. Examples thereof include diethyl carboxylate (yellow), 1,4-diacetylbenzene (cyan), and tetrazolium salt compounds described in JP-A-1-230026, JP-T 2000-504774, and the like.

The most representative dyes classified in class 2 are pyridinium compounds such as viologen. Viologen compounds have the advantages of vivid display images and the ability to change colors by changing substituents, so they are the most actively studied among organic dyes. Has been. Color development is based on organic radicals generated by reduction.

Examples of pyridinium compounds such as viologen include compounds described in each of the following patent documents starting with 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-2001-181292 JP 2001-181293, JP 2001-510590, JP 2004-101729, JP 2006-154683, JP 2006-519222, JP 2007-31708, JP 2007-. No. 171781, No. 2007-219271, No. 2007-219272, No. 2007-279659, No. 2007-279570, No. 2007-279571, No. 2007-279572. Gazette 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 electrochromic compounds]
Class 3 electrochromic compounds are compounds that are colorless or extremely light in the reduced state and exhibit a specific colored state in the oxidized state.

Examples of inorganic compounds classified as class 3 include iridium oxide (dark blue), Prussian blue (blue), etc. (each exhibiting the color shown in parentheses in the oxidized state).

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

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

Hereinafter, styryl dyes, azine dyes, and azole dyes that can be used in the present invention are exemplified, 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 electrochromic dye, and a plurality of three or more colors of black display, white display, and color display other than black are used. Perform color display. In this case, since the metal salt is reduced to display black, the electrochromic dye is preferably a class 3 electrochromic compound that develops color by oxidation.

In particular, in the present invention, from the viewpoint of refractive index, an electrochromic compound represented by the following general formula (L) according to the present invention is preferable as the electrochromic compound.

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 (eg, propargyl group, etc.), glycidyl groups, acrylate groups, methacrylate groups, aromatic groups (eg, phenyl group, naphthyl group, anthracenyl group, etc.), heterocyclic groups (eg, 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 . Preferably, Rl ₂ and Rl ₃ are each 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 connected 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.

The preferred X, is> 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 referred to in the present invention is a relatively strong adsorption state due to a chemical bond with the electrode surface, and the physical adsorption referred to in the present invention is a relatively strong van der Waals force acting between the electrode surface and the adsorbed substance. It is weakly adsorbed. The adsorptive group according to the present invention is preferably a chemisorbable group. Examples of the adsorptive group to be chemisorbed include —COOH, —P═O (OH) ₂ , —OP═O (OH) ₂ , Or -Si (OR) ₃ (R represents an alkyl group) is preferable.

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

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

These groups represented by Rl ₂₁ to Rl ₂₅ may be further substituted with an arbitrary substituent. However, at least one of the groups represented by Rl ₂₁ to Rl ₂₅ has a partial structure of —COOH, —P═O (OH) ₂ , —OP═O (OH) ₂ , or —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 compound represented by the general formula (L2) is fixed on the electrode, at least one of the groups represented by Rl ₂₁ to Rl ₂₅ has a partial structure of —P═O (OH) ₂ , —Si It is preferable to have (OR) ₃ (R represents an alkyl group), and in particular, —Si (OR) ₃ (R represents an alkyl group) as a partial structure of the group represented by Rl ₂₃ or Rl ₂₄ It is preferable to have.

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

[Metal salt compounds]
The metal salt compound according to the present invention is any compound as long as it contains a metal species that can be dissolved and precipitated by driving the counter electrode on at least one electrode on the counter electrode. There may be. Preferred metal species are silver, bismuth, copper, nickel, iron, chromium, zinc and the like, and particularly preferred are silver and bismuth.

[Silver salt compound]
The silver salt compound according to the present invention is silver or a compound containing silver in the chemical structure, such as silver oxide, silver sulfide, metallic silver, silver colloidal particles, silver halide, silver complex compound, silver ion and the like. There are no particular restrictions on the phase state species such as the solid state, the solubilized state in liquid, and the gas state, and the charged state species such as neutral, anionic, and cationic.

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

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

[Silver salt solvent]
In the present invention, a silver salt solvent can be used to promote dissolution and precipitation of metal salts (particularly silver salts). The silver salt solvent may be any compound that can solubilize silver in the electrolyte. For example, silver or a compound containing silver coexisting with a compound containing a chemical structural species that interacts with silver, such as a coordinate bond with silver or a weak supply bond with silver. It is common to use a means for converting to a solubilizate. As the chemical species, a halogen atom, a mercapto group, a carboxyl group, an imino group, and the like are known. It is characterized by low influence on coexisting compounds and high solubility in solvents.

In the display element of the present invention, the electrolyte preferably contains a compound represented by the general formula (G-1) or (G-2) as a silver salt solvent.

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

In general, in order to cause dissolution and precipitation of silver, it is necessary to solubilize silver in an electrolyte. For example, silver that causes a coordinate bond with silver and a weak covalent bond with silver can be obtained. Compounds containing chemical structural species that exhibit interaction are useful. As the chemical structural species, a halogen atom, a mercapto group, a carboxyl group, an imino group, and the like are known, but in the present invention, a compound containing a thioether group and mercaptoazoles usefully function as a silver solvent, In addition, there is a feature that the influence on the coexisting compound is small and the solubility in the solvent is high.

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

In the general formula (G-2), M represents a hydrogen atom, a metal atom, or quaternary ammonium. Z represents an atomic group necessary for constituting a nitrogen-containing heterocyclic ring. n represents an integer of 0 to 5, and Rg ₂₁ represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkylcarbonamide group, an arylcarbonamide group, an alkylsulfonamide group, an arylsulfonamide group, an alkoxy group, an aryl Oxy group, alkylthio group, arylthio group, alkylcarbamoyl group, arylcarbamoyl group, carbamoyl group, alkylsulfamoyl group, arylsulfamoyl group, sulfamoyl group, cyano group, alkylsulfonyl group, arylsulfonyl group, alkoxycarbonyl group, Represents an aryloxycarbonyl group, an alkylcarbonyl group, an arylcarbonyl group, an acyloxy group, a carboxyl group, a carbonyl group, a sulfonyl group, an amino group, a hydroxy group or a heterocyclic group, and when n is 2 or more, Of Rg ₂₁ may be the same or different, and may be linked to each other to form a condensed ring.

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

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

Hereinafter, specific examples of the compound represented by the general formula (G-1) applicable in 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 (NH) CSCH ₂ CH ₂ SC (NH) NH ₂ .2HBr
G1-32: H ₂ N (NH) CSCH ₂ CH ₂ OCH ₂ CH ₂ OCH ₂ CH ₂ SC (NH) NH ₂ .2HCl
G1-33: H ₂ N (NH) CNHCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ NHC (NH) NH ₂ .2HBr
G1-34: [(CH ₃ ) ₃ NCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ N (CH ₃ ) ₃ ] 2 ⁺ · 2Cl ⁻

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

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

In the general formula (G-2), M represents a hydrogen atom, a metal atom, or quaternary ammonium. Z represents an atomic group necessary for constituting a nitrogen-containing heterocyclic ring. n represents an integer of 0 to 5, and Rg ₂₁ represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkylcarbonamide group, an arylcarbonamide group, an alkylsulfonamide group, an arylsulfonamide group, an alkoxy group, an aryl Oxy group, alkylthio group, arylthio group, alkylcarbamoyl group, arylcarbamoyl group, carbamoyl group, alkylsulfamoyl group, arylsulfamoyl group, sulfamoyl group, cyano group, alkylsulfonyl group, arylsulfonyl group, alkoxycarbonyl group, Represents an aryloxycarbonyl group, an alkylcarbonyl group, an arylcarbonyl group, an acyloxy group, a carboxyl group, a carbonyl group, a sulfonyl group, an amino group, a hydroxy group or a heterocyclic group, and when n is 2 or more, Of Rg ₂₁ may be the same or different, and may be linked to each other to form a condensed ring.

In the general formula (G-2), examples of the metal atom represented by M include Li, Na, K, Mg, Ca, Zn, Ag, and the like. Examples of the quaternary ammonium include NH ₄ , N (CH ₃ ) ₄ , N (C ₄ H ₉ ) ₄ , N (CH ₃ ) ₃ C ₁₂ H ₂₅ , N (CH ₃ ) ₃ C ₁₆ H ₃₃ , N (CH ₃ ) ₃ CH ₂ C ₆ H ₅ Etc.

Examples of the nitrogen-containing heterocycle having Z as a constituent in the general formula (G-2) include, for example, a tetrazole ring, a triazole ring, an imidazole ring, an oxadiazole ring, a thiadiazole ring, an indole ring, an oxazole ring, a benzoxazole ring, Examples include a benzimidazole ring, a benzothiazole ring, a benzoselenazole ring, and a naphthoxazole ring.

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

Next, preferred specific examples of the compound represented by the general formula (G-2) will be 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.

[Auxiliary compounds that can be redox]
In the display element of the present invention, in order to promote the electrochemical reaction of the electrochromic material, an auxiliary compound (hereinafter referred to as a promoter) that can be oxidized and reduced may be added in addition to the electrochromic compound. 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, the electrochromic compound, and is immobilized on the electrode. It may be added to the electrolyte. These promoters can be used, for example, as counter electrode reactants or as redox mediators.

For example, when an electrochromic compound is oxidized (or reduced) in color on the display electrode side, a high color density can be obtained with a low driving voltage by using a reduction (or oxidation) reaction of a promoter on the counter electrode side. Become. Thus, when a promoter is used as a counter electrode reactant, an electrochromic compound is immobilized on a display electrode, and a promoter having redox activity opposite to that of the electrochromic compound is immobilized on a counter electrode. preferable. 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 where the white light scattering material is used in the display element and the color development by the promoter is shielded, the promoter in which the optical density in the visible region (400 to 700 nm) changes. That is, an electrochromic compound 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 the electrochromic compound on the display electrode side.

Meanwhile, 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. 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 catalyst. In addition, since oxidation at a low potential is possible, decomposition of the substrate and product can be suppressed.

In the present invention, for example, when an electrochromic compound that oxidizes and colors is used as the substrate, it is possible to drive the display element with a low driving voltage by coexisting an oxidation mediator of the catalyst, and the durability of the display element is improved. Rise. In addition, there are advantages such as an improvement in display switching speed and high coloring efficiency. Similarly, the above-described effect can be obtained by a combination of a reducing mediator and an electrochromic compound that produces a reducing 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. In the present invention, when a promoter is used as a mediator, it is preferable to fix an electrochromic compound on a display electrode and 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, a known electrochromic compound can be used. When used as a redox mediator, according to the characteristics of the electrochromic compound used as the display dye, Journal of Organic Synthetic Chemistry, Vol. 43, No. 6 (Special Issue on “Organic Synthesis Using Electric Energy”) (1985), etc. The known mediators described in 1) 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 represented by TEMPO and the like, N-hydroxyphthalimide derivatives, hydroxamic acid derivatives and the like, compounds having an N—O bond,
2) a compound having an allyloxy free radical having a bulky substituent introduced at the 0-position, such as galvinoxyl;
3) Metallocene derivatives such as ferrocene,
4) benzyl (diphenylethanedione) derivative,
5) Tetrazolium salt / formazan derivative,
6) Azine compounds such as phenazine, phenothiazine, phenoxazine, acridine,
7) Pyridinium compounds such as viologen.

In addition, hydrazyl free radical compounds such as benzoquinone derivatives, verdazil, thiazyl free radical compounds, hydrazone derivatives, phenylenediamine derivatives, triallylamine derivatives, tetrathiafulvalene derivatives, tetracyanoquinodimethane derivatives, thianthrene derivatives, etc. can also be used as promoters .

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

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

N-oxyl (also called nitroxide radical) is an oxygen-centered radical generated by radically cleaving the oxygen-hydrogen bond of hydroxylamine. Nitroxide radicals are known to have two reversible redox pairs as shown in the scheme below. The nitroxide radical becomes an oxoammonium cation by one-electron oxidation, which is reduced to regenerate the radical. The nitroxide radical is converted into 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.

The N-oxyl derivative is immobilized on the electrode surface by introducing a group that chemically or physically adsorbs to the electrode surface into the N-oxyl derivative, or by polymerizing the N-oxyl derivative to form a thin film on the electrode surface. The method of doing is mentioned. 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, TEMPO (2,2,6,6-tetramethylpiperidinyl-N-oxyl) and other derivatives substituted with various substituents are commercially available. In addition, various derivatives including polymers can be easily synthesized according to known literature.

Generally, 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. 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.

Promoters obtained by polymerizing these are, for example, JP-A Nos. 2004-227946, 2004-228008, 2006-73240, 2007-35375, 2007-70384, and 2007-184227. No. 2007, No. 2007-298713, and the like can be synthesized.

In the general formula (M1), Rm ₁₁ and Rm ₁₂ are each independently an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a heterocyclic group, or>C═O,> C═ S or a group bonded to a nitrogen atom via> C═N—Rm ₁₃ is represented. Rm ₁₃ represents a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, aromatic hydrocarbon group or heterocyclic group. Rm ₁₁ and Rm ₁₂ may be connected to each other to form a cyclic structure.

The aliphatic hydrocarbon group includes chain and cyclic groups, and the chain group includes linear and branched groups. 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 a trimer linked by these substituents, or may be a polymer.

In the general formula (M2), Rm ₂₁ , Rm ₂₂ , Rm ₂₃ and Rm ₂₄ are each independently an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic group which may have a hydrogen atom or a substituent. Represents. In addition, atoms constituting Rm ₂₁ to Rm ₂₄ and Z ₁ may be connected to each other to form a cyclic structure, and Z ₁ may further have a substituent.

In the general formula (M2), Rm ₂₁ , Rm ₂₂ , Rm ₂₃ and Rm ₂₄ are each independently an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic group which may have a hydrogen atom or a substituent. These aliphatic hydrocarbon groups, aromatic hydrocarbon groups, and heterocyclic groups have the same meanings as those in 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). The atoms constituting Rm ₂₁ to Rm ₂₄ and Z ₁ may be linked to each other to form a cyclic structure. For example, a polycyclic structure such as an azanorbornene structure or an azaadamantane structure is taken together with a nitrogen atom. Also good.

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 general formula (M3), Rm ₃₁ is an aliphatic hydrocarbon group or aromatic hydrocarbon which may be substituted directly or substituted with a carbonyl carbon atom via an oxygen atom, a nitrogen atom or a sulfur 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 ring structure.

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 (M3).

In the general formula (M3), Rm ₃₁ is an aliphatic hydrocarbon group which may be substituted, or an aromatic hydrocarbon, which is substituted directly or through a 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, and these aliphatic hydrocarbon group, aromatic carbon group About a hydrogen group and a heterocyclic group, it is synonymous with each in general formula (M1). Rm ₃₁ and Rm ₃₂ may be connected to each other to form a cyclic structure. 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 produce a display element.

In the general formula (M4), Z ₂ represents an atomic group necessary for forming a cyclic structure, and may further have a substituent.

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 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 produce a display element.

In the general formula (M5), 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.

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 general formula (M5), 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, and these aliphatic hydrocarbons The group, aromatic hydrocarbon group, and heterocyclic group have the same meanings as those 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. As Rm ₅₂ to Rm ₅₅ , an alkyl group having 1 to 6 carbon atoms is preferable, and a methyl group is particularly preferable.

In the general formula (M6), Rm ₆₁ and Rm ₆₂ each independently represent a hydrogen atom or an aliphatic hydrocarbon group which may have a substituent, and Z ₃ , Z ₄ and Z ₅ form a cyclic structure. And n represents 0 or 1.

In formula (M6), represents an aliphatic hydrocarbon group which may have a hydrogen atom or a substituent each independently _{Rm 61} and _{Rm 62,} as the _{Rm 61} and _{Rm 62} or a hydrogen atom, carbon atoms 4 The following linear alkyl groups are preferable, and at least one of Rm ₆₁ and Rm ₆₂ is preferably a hydrogen atom.

Z ₃ , Z ₄ and Z ₅ each represent 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 , Z ₄ and Z ₅ may further have a substituent.

N represents 0 or 1, but when n = 0, the general formula (M6) 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.

〔solvent〕
In the electrolyte according to the present invention, a solvent that is generally used in electrochemical cells and batteries and that can dissolve various additives such as metal salt compounds and promoters that are reversibly dissolved and precipitated by an electrochemical redox reaction is used as a solvent. can do.

Specifically, acetic anhydride, methanol, ethanol, tetrahydrofuran, ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, butylene carbonate, propylene carbonate, nitromethane, acetonitrile, acetylacetone, N-methylformamide, N, N-dimethylformamide , Dimethyl sulfoxide, hexamethylphosphoamide, dimethoxyethane, diethoxyfuran, γ-butyrolactone, γ-valerolactone, sulfolane, propionitrile, butyronitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, N-methylacetamide, N, N -Dimethylacetamide, N-methylpropionamide, methylpyrrolidinone, 2- (N-methyl) -2-pyrrole Dinone, dimethyl sulfoxide, dioxolane, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, ethyl dimethyl phosphate, tributyl phosphate, tripentyl phosphate, trihexyl phosphate, triheptyl phosphate, trioctyl phosphate, trinonyl phosphate, tridecyl phosphate, tris ( Trifluoromethyl) phosphate, tris (pentafluoroethyl) phosphate, triphenyl phosphate, tricresyl phosphate, 2-ethylhexyl phosphate, tetramethylurea, 1,3-dimethyl-2-imidazolidinone, hexamethylphosphotriamide, 4-methyl-2-pentanone, dioctyl phthalate, dioctyl sebacate, and ethylene glycol Call, diethylene glycol, polyethylene glycols such as triethylene glycol monobutyl ether and the like can be used.

Furthermore, room temperature molten salt can also be used as a solvent. The normal temperature molten salt is a salt that is melted at normal temperature consisting of only ion pairs that do not contain a solvent component, that is, a salt consisting of liquid ion pairs. The salt which consists of an ion pair which is liquid at temperature is shown. The room temperature molten salt can be used alone or in combination of two or more.

The electrolyte solvent used in the present invention is preferably an aprotic polar solvent, particularly propylene carbonate, ethylene carbonate, dimethyl sulfoxide, dimethoxyethane, acetonitrile, γ-butyrolactone, sulfolane, dioxolane, dimethylformamide, dimethoxyethane, tetrahydrofuran, adiponitrile, Methoxyacetonitrile, dimethylacetamide, methylpyrrolidinone, dimethyl sulfoxide, dioxolane, sulfolane, trimethyl phosphate and triethyl phosphate are preferred. The solvent may be used alone or in combination of two or more.

<Compounds Represented by General Formulas (S1) and (S2)>
In the present invention, particularly preferably used solvents are compounds represented by the following general formula (S1) or (S2).

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

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

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

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

Examples of 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) according to the present invention will be described.

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

Examples of 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 exemplary compounds (S1-1), (S1-2), and (S2-3) are particularly preferable.

The compounds represented by the general formulas (S1) and (S2) according to the present invention are one type of electrolyte solvent. However, in the display element of the present invention, another solvent is used as long as the object effects of the present invention are not impaired. Can be used together. Specifically, tetramethylurea, sulfolane, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, 2- (N-methyl) -2-pyrrolidinone, hexamethylphosphortriamide, N-methylpropionamide, N, N-dimethylacetamide, N-methylacetamide, N, N-dimethylformamide, N-methylformamide, butyronitrile, propionitrile, acetonitrile, acetylacetone, 4-methyl-2-pentanone, 2-butanol, 1-butanol, 2-propanol, 1-propanol, ethanol, methanol, acetic anhydride, ethyl acetate, ethyl propionate, dimethoxyethane, diethoxyfuran, tetrahydrofuran, ethylene glycol, diethylene glycol, triethylene glycol 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.M. 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, “Nonequeous Electrolytes Handbook”, Vol. 1, Academic Press (1972).

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

(Porous white scattering layer)
In the present invention, it is possible to have a porous white scattering layer containing a white scattering material from the viewpoint of further increasing display contrast and white display reflectance.

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

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

In the present invention, examples of the water-based polymer that is substantially insoluble in the electrolyte solvent include a water-soluble polymer and a polymer dispersed in the water-based solvent.

Examples of water-soluble polymers include proteins such as gelatin and gelatin derivatives, or cellulose derivatives, natural compounds such as starch, gum arabic, dextran, pullulan, and carrageenan, and other natural compounds such as polyvinyl alcohol, polyethylene glycol, polyvinyl pyrrolidone, and acrylamide. Synthetic polymer compounds such as coalescence and derivatives thereof may be mentioned. Examples of gelatin derivatives include acetylated gelatin, phthalated gelatin, polyvinyl alcohol derivatives include 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 between these vinyl monomers or other vinyl monomers (eg sodium methacrylate, methacrylic acid) Copolymers with ammonium, potassium acrylate, etc.) are also used. These binders can be used in combination of two or more.

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

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

In the present invention, the average molecular weight of the water-based polymer is preferably in the range of 10,000 to 2,000,000, more preferably in the range of 30,000 to 500,000 in terms of weight average.

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

In the present invention, among the above white pigments, titanium dioxide is preferably used. In particular, titanium dioxide surface-treated with an inorganic oxide (Al ₂ O ₃ , AlO (OH), SiO _2, etc.), in addition to these surface treatments. Titanium dioxide that has been treated with an organic substance such as trimethylolethane, triethanolamine acetate, or trimethylcyclosilane is more preferably used.

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

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.

The film thickness of the porous white scattering layer is preferably in the range of 5 to 50 μm, more preferably in the range of 10 to 30 μm.

As the solvent, an alcohol solvent having high solubility in water such as methanol, ethanol, isopropanol is preferably used, and the mixing ratio of water / alcohol solvent is preferably in the range of 0.5 to 20 by mass ratio. More preferably, it is in the range of 2-10.

In the present invention, the medium for applying the water mixture of the water-based compound and the white pigment may be any position as long as it is on the constituent element between the counter electrodes of the display element, but the electrochromic coloring layer farthest from the observation side. It is preferable to give.

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, air doctor coater, blade coater, rod coater, knife coater, squeeze coater, impregnation coater, reverse roller coater, transfer roller coater, curtain coater, double roller coater, slide hopper coater, gravure coater, kiss roll coater, bead coater, Examples include cast coaters, spray coaters, calendar coaters, and extrusion coaters.

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 it can evaporate water. For example, heating from a heat source, a heating method using infrared light, a heating method using electromagnetic induction, and the like can be given. Further, water evaporation may be performed under reduced pressure.

Porous as used in the present invention refers to the formation of a porous white scattering material by applying a water admixture of the water-based compound and the white pigment onto the electrode and drying it, and then the silver or silver is chemically treated on the scattering material. After supplying an electrolyte solution containing the compound contained in the structure, it can be sandwiched between opposing electrodes, giving a potential difference between the opposing electrodes, causing a silver dissolution precipitation reaction, and penetrating ions that can move between the electrodes Tell the state.

In the display element of the present invention, it is desirable to carry out a curing reaction of the aqueous compound with a hardener 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. No. 61-18942, 61-249054, 61-245153, JP-A-4-218044, and the like. More specifically, aldehyde hardeners (formaldehyde, etc.), aziridine hardeners, epoxy hardeners, vinyl sulfone hardeners (N, N'-ethylene-bis (vinylsulfonylacetamide) Ethane, etc.), N-methylol hardeners (dimethylolurea, etc.), boric acid, metaboric acid or polymer hardeners (compounds described in JP-A-62-234157). When gelatin is used as the aqueous compound, it is preferable to use a vinyl sulfone type hardener or a chlorotriazine type hardener alone or in combination. Moreover, when using polyvinyl alcohol, it is preferable to use boron-containing compounds such as boric acid and metaboric acid.

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

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

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

As a method for forming a porous film, a sintering method (fusing method) (using fine pores formed between particles by partially fusing polymer fine particles or inorganic particles by adding a binder, etc.), extraction method ( After forming a constituent layer with a solvent-soluble organic substance or inorganic substance and a binder that does not dissolve in the solvent, the organic substance or inorganic substance is dissolved with the solvent to obtain pores), and the polymer is heated or degassed Known forming methods such as a foaming method in which foaming is performed, a phase change method in which a mixture of polymers is phase-separated by operating a good solvent and a poor solvent, and a radiation irradiation method in which pores are formed by radiating various types of radiation Can be used. Specific examples of the electrical insulating layer include, for example, Japanese Patent Application Laid-Open No. 10-30181, Japanese Patent Application Laid-Open No. 2003-107626, Japanese Patent Publication No. 7-95403, Japanese Patent No. 2635715, Japanese Patent No. 2849523, and Japanese Patent No. 2987474. The electronic insulating layer described in JP-A No. 3066426, No. 3464513, No. 3482644, No. 3535942, No. 30622203, or the like can be given.

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

These thickeners may be used in combination of two or more. Further, compounds described on pages 71 to 75 of JP-A No. 64-13546 can be exemplified. Among these, the compounds preferably used are polyvinyl alcohols, polyvinyl pyrrolidones, hydroxypropyl celluloses, and polyalkylene glycols from the viewpoint of compatibility with various additives and improvement in dispersion stability of white particles.

[Other additives]
For the electrolyte of the display element of the present invention, other additives for the purpose of improving various performances can be used. They are selected according to the purpose and are not particularly limited.

Various chemical sensitizers, noble metal sensitizers, photosensitive dyes, supersensitizers, couplers, high boiling solvents, antifoggants, stabilizers, development inhibitors, bleach accelerators, fixing accelerators, color mixing inhibitors, Formalin Scavenger, Toning Agent, Hardener, Surfactant, Thickener, Plasticizer, Slipper, Ultraviolet Absorber, Irradiation Dye, Filter Light Absorbing Dye, Antibacterial Agent, Polymer Latex, Heavy Metal, Antistatic Agent Further, a matting agent or the like can be contained as necessary.

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

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

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

〔substrate〕
The substrate constituting the display element of the present invention is preferably a transparent substrate. Examples of such a transparent substrate include polyester (for example, polyethylene terephthalate), polyimide, polymethyl methacrylate, polystyrene, polypropylene, polyethylene, Polyamide, nylon, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyether sulfone, silicon resin, polyacetal resin, fluororesin, cellulose derivative, polyolefin film, plate-like substrate, glass substrate and the like are preferably used. The transparent substrate used in the present invention refers to a substrate having a transmittance for visible light of at least 50%. Further, as the counter substrate, for example, an opaque substrate such as an inorganic substrate such as a metal substrate or a ceramic substrate can be used.

〔electrode〕
(Display side electrode)
A transparent electrode that transmits at least visible light is used for the display-side electrode. For example, Indium Tin Oxide (ITO: Indium Tin Oxide), Indium Zinc Oxide (IZO: Indium Zinc Oxide), Fluorine Doped Tin Oxide (FTO), Indium Oxide, Zinc Oxide, Platinum, Gold, Silver, Rhodium, Copper, Examples thereof include chromium, carbon, aluminum, silicon, amorphous silicon, and BSO (Bismuth Silicon Oxide).

Also, polythiophene, polypyrrole, polyaniline, polyacetylene, polyparaphenylene, polyselenophenylene, etc., and their modifying compounds can be used alone or in combination.

The surface resistance value indicating the conductivity of the display-side electrode is preferably 100Ω / □ or less, and more preferably 10Ω / □ or less. The thickness of the electrode is not particularly limited, but is generally 0.1 to 20 μm.

(Transparent porous electrode)
A nanoporous electrode having a nanoporous structure can be provided on the surface of the display side electrode. This nanoporous electrode is substantially transparent when a display element is formed, and can carry an electroactive substance such as an electrochromic dye.

The nanoporous structure referred to in the present invention refers to a state in which an infinite number of nanometer-sized pores exist in a layer and ionic species contained in the electrolyte can move within the nanoporous structure.

As a method for forming such a nanoporous electrode, a dispersion containing fine particles constituting the nanoporous electrode is formed in layers by an ink jet method, a screen printing method, a blade coating method, etc., and then heated at a predetermined temperature. A method of making porous by drying, baking, a method of making nanoporous by anodizing or photoelectrochemical etching after forming an electrode layer by sputtering, CVD, atmospheric pressure plasma, etc. Is mentioned. Also, the sol-gel method, Adv. Mater. It can also be formed by the method described in 2006, 18, 2980-2983.

The main components of the fine particles constituting the nanoporous electrode are metals such as Cu, Al, Pt, Ag, Pd and Au, metal oxides such as ITO, SnO ₂ , TiO ₂ and ZnO, carbon nanotubes, glassy carbon, and diamond. It can be selected from carbon electrodes such as like carbon and nitrogen-containing carbon, and is preferably selected from metal oxides such as ITO, SnO ₂ , TiO ₂ , and ZnO.

In order for the nanoporous electrode to be transparent, it is preferable to use fine particles having an average particle diameter of about 5 nm to 10 μm. As the shape of the fine particles, those having an arbitrary shape such as an indefinite shape, a needle shape, and a spherical shape can be used.

The film thickness of the nanoporous electrode is preferably in the range of 0.1 to 10 μm, more preferably in the range of 0.25 to 5 μm.

(Counter electrode)
Since the counter electrode can be used without being involved in the display color, it can be used without particular limitation as long as it conducts electricity.

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

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

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

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

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

As a method for forming the auxiliary electrode, a known method can be used. For example, a patterning method by photolithography, a printing method, an ink jet method, electrolytic plating or electroless plating, or a method of forming a pattern by exposing and developing using a silver salt photosensitive material may be used. Although the line width and line interval of the auxiliary electrode pattern of the present invention may be arbitrary values, it is necessary to increase the line width in order to increase the conductivity. On the other hand, when an auxiliary electrode is attached to the transparent electrode, from the viewpoint of visibility, the area coverage of the auxiliary electrode viewed from the display element observation side is preferably 30% or less, and more preferably 10% or less.

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

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

Also, electrodes can be formed by electrolytic plating, electroless plating, printing methods, and ink jet methods.

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

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

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

(Electrostatic inkjet)
In the display element of the present invention, at least one of the transparent electrode of the composite electrode and the metal auxiliary electrode supplies a liquid discharge head having a nozzle with an internal diameter of 30 μm or less for discharging charged liquid, and a solution into the nozzle. It is preferably formed using a liquid discharge apparatus including a supply unit and a discharge voltage application unit that applies a discharge voltage to the solution in the nozzle.

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

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

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

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

[Other components of the display element]
In the display element of the present invention, a sealant, a columnar structure, and spacer particles can be used as necessary.

Sealing agent is for sealing so that it does not leak 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 properly maintained at intervals of the substrate, such as an evenly spaced array, an array in which the interval gradually changes, and an array in which a predetermined arrangement pattern is repeated at a constant period. The arrangement is preferably considered so as not to disturb the display. If the ratio of the area occupied by the columnar structure 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 spacer diameter corresponds to the cell gap thickness.

[Display element driving method]
The driving operation of the display element of the present invention may be simple matrix driving or active matrix driving. The simple matrix driving in the present invention is a driving method in which a current is sequentially applied to a circuit in which a positive line including a plurality of positive electrodes and a negative electrode line including a plurality of negative electrodes are opposed to each other in a vertical direction. Say that. By using simple matrix driving, there is an advantage that the circuit configuration and driving IC can be simplified and manufactured at low cost. The active matrix drive is a system in which scanning lines, data lines, and current supply lines are formed in a grid pattern, and are driven by TFT circuits provided in each grid pattern. Since switching can be performed for each pixel, there are merits such as gradation and memory function. For example, a circuit described in FIG. 5 of JP-A-2004-29327 can be used.

[Product application]
The display element of the present invention can be used in an electronic book field, an ID card field, a public field, a traffic field, a broadcast field, a payment field, a distribution logistics field, and the like. Specifically, keys for doors, student ID cards, employee ID cards, various membership cards, convenience store cards, department store cards, vending machine cards, gas station cards, subway and railway cards, bus cards, Cash cards, credit cards, highway cards, driver's licenses, hospital examination cards, electronic medical records, health insurance cards, Basic Resident Registers, passports, electronic books, etc.

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

<< Preparation of electrolyte >>
(Preparation of electrolyte 1)
In 2.5 parts by mass of propylene carbonate, 0.1 part by mass of bis (trifluoromethanesulfonyl) imide lithium and carboxy TEMPO (4-carboxy-2,2,6,6-tetramethylpiperidine-1-oxyl free The electrolyte 1 was prepared by dissolving 0.05 part by mass of radicals.

(Preparation of electrolyte 2)
In 2.5 parts by mass of dimethyl sulfoxide, 0.1 part by mass of bismuth chloride, 0.2 part by mass of lithium bromide, and 0.025 part by mass of tetrabutylammonium perchlorate are dissolved, and electrolyte 2 is obtained. Prepared.

(Preparation of electrolyte 3)
Electrolyte 3 was prepared by dissolving 0.1 parts by mass of bis (trifluoromethanesulfonyl) imide lithium and 0.1 parts by mass of silver p-toluenesulfonate in 2.5 parts by mass of dimethyl sulfoxide.

(Preparation of electrolyte 4)
In 2.5 parts by mass of dimethyl sulfoxide, 0.1 part by mass of bis (trifluoromethanesulfonyl) imide lithium, 0.1 part by mass of silver p-toluenesulfonate, and 0% of exemplary compound (G1-3) Electrolyte 4 was prepared by dissolving 2 parts by mass.

(Preparation of electrolyte 5)
In 2.5 parts by mass of dimethyl sulfoxide, 0.1 part by mass of bis (trifluoromethanesulfonyl) imide lithium, 0.1 part by mass of silver p-toluenesulfonate, and 0% of exemplary compound (G2-12) Electrolyte 5 was prepared by dissolving 2 parts by mass.

(Preparation of electrolyte 6)
In 25 parts by mass of propylene carbonate, 7.0 parts by mass of bis (trifluoromethanesulfonyl) imide lithium and 0.2 parts by mass of pyrrole were dissolved to obtain an electrolyte 6.

<Production of electrode>
(Production of electrode 1)
An ITO (Indium Tin Oxide) film having a thickness of 1 cm is formed as a conductive layer on a glass substrate having a thickness of 1.5 mm and a width of 2 cm × 4 cm according to a known method, thereby producing an electrode 1. did.

(Preparation of electrode 2)
On the ITO film-forming surface of the electrode 1, the following titanium dioxide dispersion was screen-printed so that the average film thickness after drying was 20 μm, and then dried at 50 ° C. for 30 minutes to evaporate the solvent. The electrode 2 having a porous white scattering layer was produced by drying in an atmosphere of 1 ° C. for 1 hour.

<Preparation of titanium dioxide dispersion>
After adding Kuraray Poval PVA235 (manufactured by Kuraray Co., Ltd., polyvinyl alcohol resin) to a water / ethanol (1/1) mixed solution so as to have a solid content concentration of 2% by mass and dissolving with heating, titanium dioxide CR- 90 (manufactured by Ishihara Sangyo Co., Ltd.) was dispersed with an ultrasonic dispersing machine so as to be 20% by mass to obtain a titanium dioxide dispersion.

(Preparation of electrode 3)
The electrode 1 and the platinum electrode are arranged at positions facing each other, and this electrode pair is immersed in a glass container containing the electrolyte 6 until the amount of electricity supplied between the electrode 1 and the platinum electrode is 12 mC / cm ^2. A voltage of 3 V was applied, and a polypyrrole film formed by electrolytic polymerization of pyrrole was formed on the electrode 1. The electrode 1 on which the polypyrrole film was formed was taken out of the glass container, washed with ethanol, and dried to obtain an electrode 3.

(Preparation of electrode 4)
On the surface of the electrode 1 on which the ITO film was formed, a titanium dioxide layer having a thickness of 0.085 μm (about 4 to 10 particles having an average particle diameter of 10 nm had been necked) was formed, whereby an electrode 4 was produced.

(Preparation of electrode 5)
An electrode 5 was produced in the same manner as in the production of the electrode 3 except that the electrode 4 was used instead of the electrode 1.

(Preparation of electrode 6)
The electrode 4 was immersed in the following treatment liquid 1 and allowed to stand at room temperature for about 24 hours, then washed with ethanol and dried to produce an electrode 6.

<Preparation of treatment liquid 1>
In 20 parts by mass of pure water, 0.05 part by mass of the following compound (A-1), 0.06 part by mass of the following compound (A-2), and 0.07 part of the following compound (A-3) A treatment liquid 1 was prepared by dissolving a part by mass.

(Preparation of electrode 7)
On the ITO film forming surface of electrode 1, a 0.075 μm thick titanium dioxide layer (about 4 to 10 particles having an average particle diameter of 10 nm had been necked) was formed, and electrode 7 was produced.

(Preparation of electrode 8)
An electrode 8 was produced in the same manner as in the production of the electrode 6 except that the electrode 7 was used instead of the electrode 4.

(Preparation of electrode 9)
The electrode 1 and the platinum electrode are arranged at opposite positions, and this electrode pair is immersed in a glass container containing the electrolyte 6 until the amount of electricity supplied between the electrode 1 and the platinum electrode is 40 mC / cm ^2. A voltage of 3 V was applied, and a polypyrrole film formed by electrolytic polymerization of pyrrole was formed on the electrode 1. The electrode 1 on which the polypyrrole film was formed was taken out from the glass container, washed with ethanol, and dried to obtain an electrode 9.

(Production of electrode 10)
On the surface of the electrode 1 on which the ITO film was formed, a titanium dioxide layer having a thickness of 1.0 μm (about 4 to 10 particles having an average particle diameter of 10 nm had been necked) was formed.

(Preparation of electrode 11)
In the production of the electrode 9, an electrode 11 was produced in the same manner except that the electrode 10 was used instead of the electrode 1.

(Preparation of electrode 12)
An electrode 12 was produced in the same manner as in the production of the electrode 6 except that the electrode 10 was used instead of the electrode 4.

(Preparation of electrode 13)
On the surface of the electrode 1 on which the ITO film was formed, a titanium dioxide layer having a thickness of 0.06 μm (about 4 to 10 particles having an average particle diameter of 10 nm had been necked) was formed, whereby an electrode 13 was produced.

(Preparation of electrode 14)
An electrode 14 was produced in the same manner as in the production of the electrode 3 except that the electrode 13 was used instead of the electrode 1.

(Preparation of electrode 15)
The electrode 4 was immersed in the following treatment liquid 2 and allowed to stand at room temperature for about 24 hours, then washed with ethanol and dried to produce an electrode 15.

<Preparation of treatment liquid 2>
The treatment liquid 2 was prepared by dissolving 0.18 parts by mass of the exemplified compound (L19) as an electrochromic compound in 20 parts by mass of pure water.

(Preparation of electrode 16)
The electrode 4 was immersed in the following treatment liquid 3 and allowed to stand at room temperature for about 24 hours, then washed with ethanol and dried to produce an electrode 16.

<Preparation of treatment liquid 3>
The treatment liquid 3 was prepared by dissolving 0.18 parts by mass of the exemplified compound (L29) as an electrochromic compound in 20 parts by mass of pure water.

<< Production of display element >>
(Preparation of display element 1)
The peripheral part of the electrode 2 prepared above was trimmed with an olefin-based sealant containing glass spherical beads having an average particle diameter of 40 μm as a volume fraction of 10%, and then the electrodes 2 and 3 were respectively striped. The electrodes were bonded so as to be orthogonal to each other and further heated and pressed to produce an empty cell. The electrolyte 1 was vacuum-injected into the empty cell, and the injection port was sealed with an epoxy-based ultraviolet curable resin to produce a display element 1.

(Preparation of display element 2)
A display element 2 was produced in the same manner as in the production of the display element 1 except that the electrode 5 was used instead of the electrode 3.

(Preparation of display element 3)
A display element 3 was produced in the same manner as in the production of the display element 1 except that the electrode 6 was used instead of the electrode 3.

(Preparation of display element 4)
A display element 4 was produced in the same manner as in the production of the display element 1 except that the electrode 8 was used instead of the electrode 3.

(Preparation of display element 5)
A display element 5 was produced in the same manner as in the production of the display element 1 except that the electrolyte 2 was used instead of the electrolyte 1 and the electrode 13 was used instead of the electrode 3.

(Preparation of display element 6)
A display element 6 was produced in the same manner as in the production of the display element 5 except that the electrolyte 3 was used instead of the electrolyte 2.

(Preparation of display element 7)
A display element 7 was produced in the same manner as in the production of the display element 5 except that the electrolyte 4 was used instead of the electrolyte 2.

(Preparation of display element 8)
A display element 8 was produced in the same manner as in the production of the display element 5 except that the electrolyte 5 was used instead of the electrolyte 2.

(Preparation of display element 9)
A display element 9 was produced in the same manner as in the production of the display element 1 except that the electrode 9 was used instead of the electrode 3.

(Preparation of display element 10)
A display element 10 was produced in the same manner as in the production of the display element 2 except that the electrode 11 was used instead of the electrode 5.

(Preparation of display element 11)
A display element 11 was produced in the same manner as in the production of the display element 3 except that the electrode 12 was used instead of the electrode 6.

(Preparation of display element 12)
A display element 12 was produced in the same manner as in the production of the display element 5 except that the electrode 1 was used instead of the electrode 13.

(Preparation of display element 13)
A display element 13 was produced in the same manner as in the production of the display element 6 except that the electrode 1 was used instead of the electrode 13.

(Preparation of display element 14)
A display element 14 was produced in the same manner as in the production of the display element 1 except that the electrode 14 was used instead of the electrode 3.

(Preparation of display element 15)
A display element 15 was produced in the same manner as in the production of the display element 6 except that the electrode 4 was used instead of the electrode 13.

(Preparation of display element 16)
A display element 16 was produced in the same manner as in the production of the display element 7 except that the electrode 15 was used instead of the electrode 13.

(Preparation of display element 17)
A display element 17 was produced in the same manner as in the production of the display element 7 except that the electrode 16 was used instead of the electrode 13.

<< Evaluation of display element >>
The reflectance at a wavelength of 550 nm before applying the voltage of each display element (white display state) was measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing. Next, the reflectance at a wavelength of 550 nm when both electrodes of the display element are connected to an electrochemical measuring apparatus HSV-100 (manufactured by Hokuto Denko) and a voltage of 1.5 V is applied to each display element for color display. Measurement was performed with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing. The measurement was repeated by appropriately adjusting the voltage application time, and the amount of charge consumed until the reflectance became 1/10 of the voltage before application (CR10 charge amount (mC / cm ² )) was measured.

Further, the refractive index (n ₂ , n ₁ ) and the thickness of the color space (d ₂ , d ₁ ) before applying the voltage of each display element (white display) and when color display is performed are set to an environment of 25 ° C. below, it was measured using a spectroscopic ellipsometer FE-5000 (manufactured by Otsuka Electronics) _to determine _{n 1, d 1, n 2} , d 2 , respectively.

The results obtained are shown in Table 2. The lower the CR10 charge amount, the lower the power consumption.

As is clear from the results shown in Table 2, it can be seen that the display element of the present invention has a lower CR10 charge amount and can be driven with lower power consumption than the comparative example.

DESCRIPTION OF SYMBOLS 1 Display element 2 Conductive electrode 3 Porous white scattering layer 4 Coloring space 5 Transparent electrode A The upper surface of the coloring space 4 B The lower surface of the coloring space 4 C Visible light

Claims (9)

A display element having a color space between at least a pair of opposing electrodes, wherein the color space satisfies the following formulas (1) and (2).
Formula (1)
n ₂ · d ₂ ≦ 90 or n ₂ · d ₂ ≧ 185
Formula (2)
100 ≦ n ₁ · d ₁ ≦ 175
[Where n ₁ and d ₁ are the refractive index n ₁ and thickness d ₁ (nm) of the coloring space when the display element is colored (or black), respectively, and n ₂ and d ₂ are The refractive index n ₂ and the thickness d ₂ (nm) of the coloring space in the white display state. ] The display element according to claim 1, further comprising an electrolyte between the pair of opposed electrodes, and the coloring space contains an electrochromic compound. The display element according to claim 2, wherein the electrochromic compound is an organic dye. The display element according to claim 2, wherein the electrochromic compound is a compound represented by the following general formula (L).

[Wherein, Rl ₁ represents a substituted or unsubstituted aryl group, and Rl ₂ and Rl ₃ each represent a hydrogen atom or a substituent. X represents> N—Rl ₄ , an oxygen atom or a sulfur atom, and Rl ₄ represents a hydrogen atom or a substituent. ] The display element according to claim 4, wherein the compound represented by the general formula (L) is a compound represented by the following general formula (L2).

Wherein Rl ₂₁ and Rl ₂₂ each represents an aliphatic group, an aliphatic oxy group, an acylamino group, a carbamoyl group, an acyl group, a sulfonamide group or a sulfamoyl group, and Rl ₂₃ represents an aromatic group or an aromatic heterocyclic group Rl ₂₄ represents a hydrogen atom, an aliphatic group, an aromatic group or an aromatic heterocyclic group, and Rl ₂₅ represents a hydrogen atom, an aliphatic group, an aromatic group or an acyl group. ] The display element according to any one of claims 2 to 5, wherein the electrochromic compound is fixed to a transparent porous electrode. The display element according to any one of claims 2 to 6, wherein a metal salt compound is contained in the electrolyte, and black display and white display are performed by a driving operation of the opposing electrode. The display element according to claim 7, wherein the metal salt compound is a silver salt compound. The display element according to claim 7 or 8, wherein the electrolyte further contains a compound represented by the following general formula (G-1) or (G-2).
General formula (G-1)
Rg ₁₁ -S-Rg ₁₂
[Wherein, Rg ₁₁ and Rg ₁₂ each represent a substituted or unsubstituted hydrocarbon group. Further, these hydrocarbon groups may contain one or more nitrogen atom, oxygen atom, phosphorus atom, sulfur atom or halogen atom, and Rg ₁₁ and Rg ₁₂ may be connected to each other to take a cyclic structure. ]

[Wherein, 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 hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkylcarbonamide group, an arylcarbonamide group, an alkylsulfonamide group, an arylsulfonamide group, an alkoxy group, an aryl Oxy group, alkylthio group, arylthio group, alkylcarbamoyl group, arylcarbamoyl group, carbamoyl group, alkylsulfamoyl group, arylsulfamoyl group, sulfamoyl group, cyano group, alkylsulfonyl group, arylsulfonyl group, alkoxycarbonyl group, Represents an aryloxycarbonyl group, an alkylcarbonyl group, an arylcarbonyl group, an acyloxy group, a carboxyl group, a carbonyl group, a sulfonyl group, an amino group, a hydroxy group or a heterocyclic group, and when n is 2 or more, Of Rg ₂₁ may be the same or different, and may be linked to each other to form a condensed ring. ]

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