JP2009237264A - Display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display element constituted by simple members, capable of being driven by low voltage, achieving high contrast in display in black, reducing fluctuation of color tone in display in black, and displaying in color. <P>SOLUTION: This display element has electrolyte and white-colored scattered substances between opposing electrodes. Two kinds of compounds expressed by the following formula (L) (wherein, R1<SB>1</SB>denotes a substituted or non-substituted aryl group, R1<SB>2</SB>and R1<SB>3</SB>denote hydrogen atom or substituent each, X&gt;N-R1<SB>4</SB>, and X denotes oxygen atom or sulfur atom and R1<SB>4</SB>denotes hydrogen atom or substituent) are fixed on at least either of the opposing electrodes. By applying voltage V<SB>1</SB>(V) between the opposing electrodes, the compound expressed by the first type of formula (L) is colored to display in red, green or blue. By applying voltage V<SB>2</SB>(V) between the opposing electrodes further while the compound expressed by the first type of formula (L) is colored, the compound expressed by the second type of formula (L) is colored to display in black. The voltage V<SB>1</SB>and the voltage V<SB>2</SB>satisfy the following relation: V<SB>2</SB>&gt;V<SB>1</SB>&gt;0. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a novel electrochemical display element.

  In recent years, with the increase in the operating speed of personal computers, the spread of network infrastructure, the increase in capacity and price of data storage, information such as documents and images provided on printed paper on paper has become easier to use electronic information. Opportunities to obtain and browse electronic information are increasing more and more.

  As a means for browsing such electronic information, a conventional liquid crystal display or CRT, and in recent years, a light emitting type such as an organic EL display is mainly used. In particular, when the electronic information is document information, it is relatively long time. It is necessary to pay close attention to this browsing means, and these actions are not necessarily human-friendly means. Generally, as a drawback of light-emitting displays, eyes flicker due to flickering, inconvenient to carry, reading posture is limited It is known that it is necessary to adjust the line of sight to a still screen, and that power consumption increases when read for a long time.

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

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

The electrochromic method is known as a method capable of full-color display, and can be driven at a low voltage of 3 V or less. 3 layers need to be laminated, and there is a concern about high cost due to a complicated element configuration. Further, a full-color electrochromic device (for example, refer to Patent Document 1) using flat ground mixing is known. However, this method has a problem that black and white contrast is not sufficient because dark black cannot be obtained due to flat ground mixing. Was. In addition, a method using a polypyridine compound in an electrochromic device is known (for example, see Patent Document 2). However, with this configuration, only two colors can be displayed as display colors, and in particular, black display cannot be obtained. Had. In addition, an electrochromic element (for example, see Patent Document 3) that performs full color display using two or more types of viologen compounds having different threshold voltages necessary for color development is known. However, this method does not have sufficient memory properties. For this reason, there is a problem that the color variation of black display is large.
JP 2003-270670 A Japanese Patent No. 2930860 JP 2006-106669 A

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a display capable of color display that has a simple member configuration, can be driven at a low voltage, has a high black display contrast, and has a small black tone variation. It is to provide an element.

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

1. There are an electrolyte and a white scatterer between the counter electrodes, and two kinds of compounds represented by the following general formula (L) are immobilized on at least one counter electrode, and a voltage V ₁ (V ), The first type of the compound represented by the general formula (L) is colored to display red, green or blue, and the first type of the compound represented by the general formula (L) In the state where is colored, a voltage V ₂ (V) is further applied between the counter electrodes to color the second type compound represented by the general formula (L), thereby displaying black. The display element, wherein the voltage V ₁ and the voltage V ₂ satisfy a relationship of V ₂ > V ₁ > 0.

[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. ]
2. The other counter electrode different from the counter electrode on which the compound represented by the general formula (L) is immobilized is represented by a compound represented by the following general formula (A) or the following general formula (B). 2. The display element according to 1 above, wherein the compound is immobilized.

[Wherein, Ra ₁ , Ra ₂ , Rb ₁ and Rb ₂ each independently represent an aromatic hydrocarbon group, an aromatic heterocyclic group or an aliphatic hydrocarbon group which may have a substituent. Ra ₁ and Ra ₂ , Rb ₁ and Rb ₂ may be connected to each other to form a cyclic structure. ]
3. _{2. In the} item ₂ , wherein Ra ₁ and Ra ₂ in the general formula (A) and Rb ₁ and Rb _{2 in} the general formula (B) are each an aromatic hydrocarbon group or an aromatic heterocyclic group. The display element as described.

4). In the general formula (A), Ra ₁ and Ra ₂ and Rb ₁ and Rb _{2 in} the general formula (B) are each an aromatic hydrocarbon group substituted with an electron-withdrawing group or an electron-deficient aromatic heterocyclic ring. 4. The display element as described in 2 or 3 above, which is a group.

  5). 5. The display element according to any one of 1 to 4, wherein the electrolyte contains an N-oxyl derivative.

6). There are an electrolyte and a white scatterer between the counter electrodes, and at least one counter electrode has two kinds of compounds represented by the following general formula (L) immobilized thereon, and a voltage V ₃ (V ) To display black by coloring the two types of compounds represented by the general formula (L), and applying the voltage V ₄ (V) between the counter electrodes allows the two types to be displayed. By decoloring any one of the compounds represented by the general formula (L), red, green or blue is displayed, and the voltage V ₃ and the voltage V ₄ are V ₃ >0> V _4. A display element characterized by satisfying the relationship:

[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. ]
7). The other counter electrode different from the counter electrode on which the compound represented by the general formula (L) is immobilized is represented by a compound represented by the following general formula (A) or the following general formula (B). 7. The display element according to 6 above, wherein the compound is immobilized.

[Wherein, Ra ₁ , Ra ₂ , Rb ₁ and Rb ₂ each independently represent an aromatic hydrocarbon group, an aromatic heterocyclic group or an aliphatic hydrocarbon group which may have a substituent. Ra ₁ and Ra ₂ , Rb ₁ and Rb ₂ may be connected to each other to form a cyclic structure. ]
8). In the item 7, wherein Ra ₁ and Ra ₂ in the general formula (A) and Rb ₁ and Rb _{2 in} the general formula (B) are each an aromatic hydrocarbon group or an aromatic heterocyclic group. The display element as described.

9. In the general formula (A), Ra ₁ and Ra ₂ and Rb ₁ and Rb _{2 in} the general formula (B) are each an aromatic hydrocarbon group substituted with an electron-withdrawing group or an electron-deficient aromatic heterocyclic ring. 9. The display element as described in 7 or 8 above, which is a group.

  10. 10. The display element according to any one of 6 to 9, wherein the electrolyte contains an N-oxyl derivative.

  According to the present invention, it is possible to provide a display element capable of color display that has a simple member configuration, can be driven at a low voltage, has a high black display contrast, and has a small black tone color variation.

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

As a result of intensive studies in view of the above problems, the present inventor,
1) An electrolyte and a white scatterer are provided between the counter electrodes, and at least one of the counter electrodes is fixed with two types of compounds represented by the general formula (L), and the voltage V ₁ is applied between the counter electrodes. By applying (V), the first-type compound represented by the general formula (L) is colored to display red, green or blue, and is represented by the first-type general formula (L). In the state where the compound is colored, a voltage V ₂ (V) is further applied between the counter electrodes to color the compound represented by the second type of the general formula (L), thereby displaying black. A display element, wherein the voltage V ₁ and the voltage V ₂ satisfy a relationship of V ₂ > V ₁ > 0,
Or
2) An electrolyte and a white scatterer are provided between the counter electrodes, and at least one of the counter electrodes is fixed with two types of compounds represented by the general formula (L), and a voltage V ₃ is applied between the counter electrodes. By applying (V), the compound represented by the two general formulas (L) is colored to display black, and by applying a voltage V ₄ (V) between the counter electrodes, By decoloring any one of the two types of compounds represented by the general formula (L), red, green or blue is displayed, and the voltage V ₃ and the voltage V ₄ are V ₃ >0>. A display element characterized by satisfying the relationship of V ₄ ,
As a result, it has been found that a display element capable of color display capable of being driven with a simple member configuration, low voltage, high black display contrast, and small black color tone variation can be realized.

  Details of the present invention will be described below.

[Basic structure of display element]
In the display element of the present invention, the display portion is provided with one corresponding counter electrode. A transparent electrode such as an ITO electrode and a porous electrode such as a TiO 2 electrode are provided on the electrode 1 which is one of the counter electrodes close to the display portion, and a conductive electrode is provided on the other electrode 2. Between the electrode 1 and the electrode 2, the electrolyte according to the present invention and a white scatterer are provided, and two types of compounds represented by the general formula (L) according to the present invention are immobilized on the electrode 1, By applying positive and negative voltages between the opposing electrodes, it is possible to reversibly switch between white display, black display, and color display other than black.

[Display color switching method]
The display color switching method of the display element of the present invention is selected from the following two driving methods according to the characteristics of the compounds represented by the two general formulas (L) used and the application of the display element. It is characterized by.

(Driving method 1)
Of the two compounds represented by the general formula (L) according to the present invention, the color of the compound represented by the first general formula (L) is red, and the second general formula (L ) Is cyan, and 0 <the threshold voltage of the coloring state of the first type compound <the threshold voltage of the coloring state of the second type compound is satisfied. A voltage V ₁ that is noble than the threshold voltage of the coloring state of the compound represented by the first general formula (L) and lower than the threshold voltage of the coloring state of the compound represented by the second general formula (L). By applying between the counter electrodes, the white display state can be switched to the red display state. Since the compound represented by the general formula (L) according to the present invention has a sufficiently high memory property, the threshold value of the coloring state of the second type compound regardless of the elapsed time after displaying the red color. By applying a voltage V ₂ that is nobler than the voltage for a predetermined time between the opposing electrodes, it is possible to switch from a red display state to a black display state. The driving method 1 according to the present invention is the same when the combination of the coloring states of the two compounds represented by the general formula (L) is green and magenta, and blue and yellow.

(Driving method 2)
The coloring states of the two compounds represented by the general formula (L) according to the present invention are red and cyan, respectively, and 0> decoloration of the compound represented by the first general formula (L) When the relationship between the threshold voltage of the state> the threshold voltage of the decolored state of the compound represented by the second general formula (L) is satisfied, the coloring of the compound represented by the first general formula (L) The voltage V ₃ which is nobler than the threshold voltage of the state and the threshold voltage of the coloring state of the compound represented by the second general formula (L) is applied between the counter electrodes to switch from the white display state to the black state. be able to. Since the compound represented by the general formula (L) according to the present invention has a sufficiently high memory property, the second general formula (L) is used regardless of the elapsed time after displaying black. By applying a voltage V ₄ which is nobler than the threshold voltage in the decoloring state of the compound represented for a predetermined time between the counter electrodes, the black display state can be switched to the red display state. The driving method 2 according to the present invention is the same when the combinations of the coloring states of the compounds represented by the two general formulas (L) are green and magenta, and blue and yellow.

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

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

  Although there is no restriction | limiting in particular as a boiling point of the solvent of electrolyte, From the point of volatility prevention and a manufacturing reason, it is preferable that it is a high boiling point, and it is preferable to have a boiling point of 200 degreeC or more.

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

<Compounds Represented by General Formulas (S1) and (S2)>
In the display element of the present invention, the electrolyte preferably contains a compound represented by the following general formula (S1) or (S2).

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

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

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

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

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

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

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

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

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

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

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

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

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

  There are no particular limitations on the salts, and for example, inorganic ion salts such as alkali metal salts and alkaline earth metal salts; quaternary ammonium salts; cyclic quaternary ammonium salts; quaternary phosphonium salts and the like can be used.

Specific examples of the salts include halogen ions, SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ and 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 ⁻ , or K salt is mentioned.

Also, halogen ions, SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ 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.

Also, halogen ions, SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ 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, include _{(C 4 H 9) 4 PBF} 4 and the like. Moreover, these mixtures can also be used suitably.

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

  The amount of the electrolyte salt used is arbitrary, but generally, the electrolyte salt is present in the solvent as an upper limit of 20 mol / L or less, preferably 10 mol / L or less, more preferably 5 mol / L or less. Desirably, 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.

(N-oxyl derivative)
In the display element of the present invention, the electrolyte preferably contains an N-oxyl derivative.

  The N-oxyl derivative according to the present invention may function as a mediator of an electrodeposition reaction or an electrochromic reaction or may function as a counter electrode reactant. When functioning as a mediator, the electrodeposition reaction or the electrochromic reaction In the case of functioning as a counter electrode reactant, it is desirable to have an activity opposite to that of the electrodeposition reaction or electrochromic reaction.

<Compound represented by formula (1)>
The N-oxyl derivative applicable to the display device of the present invention is not particularly limited, but is preferably a compound represented by the following general formula (1).

In the general formula (1), R ¹ and R ² are each independently an aliphatic hydrocarbon group, aromatic hydrocarbon group, heterocyclic group or>C═O,> C═S, which may have a substituent. ,> C represents a group bonded to a nitrogen atom via N-Rc. Rc represents a hydrogen atom or an optionally substituted aliphatic hydrocarbon group, aromatic hydrocarbon group or heterocyclic group. R ¹ and R ² 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 (for example, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (for example, 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 (for example, phenylthio group, 1-naphthylthio group, etc.), heterocyclic thio group (for example, 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 (For example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group, etc.), acyl group (for example, 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, acetyloxy, pivaloyloxy, stearoyloxy, benzoyloxy, p-methoxyphenylcarbonyloxy, ethylcarbonyloxy, 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), 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 (for example, 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, etc.), phosphino group (for example, dimethylphosphino group, diphenylphosphino group, methylphenoxyphosphino group, etc.), phosphinyl group (for example, 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 can be mentioned.

  The compound represented by the general formula (1) may be a multimer such as a dimer or trimer linked by these substituents, or may be a polymer.

  Specific examples of the compound represented by the general formula (1) are shown below, but the present invention is not limited to these exemplified compounds.

  In addition, as a compound represented by General formula (1) based on this invention, the specific compound of the compound represented by General formula (2)-(5) demonstrated below is included.

  In the present invention, the N-oxyl derivative is preferably at least one selected from compounds represented by the following general formulas (2) to (5).

<Compound represented by formula (2)>
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 following general formula (2).

In the general formula (2), R ³ , R ⁴ , R ⁵ and R ⁶ are each independently an aliphatic hydrocarbon group, aromatic hydrocarbon group or heterocyclic group which may have a hydrogen atom or a substituent. Represents. The aliphatic hydrocarbon group, aromatic hydrocarbon group, and heterocyclic group have the same meanings as those in the general formula (1).

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 (1). Further, the atoms constituting R ^{3 to} R ⁶ and Z ₁ may be linked to each other to form a cyclic structure. For example, together with the nitrogen atom, a polycyclic structure such as an azanorbornene structure or an azaadamantane structure is taken. Also good.

  The ring structure of the compound represented by the general formula (2) is preferably a piperidine ring, a pyrrolidine ring, or an azaadamantane ring.

  Specific examples of the compound represented by the general formula (2) are shown below, but the present invention is not limited to these exemplified compounds.

<Compound represented by formula (3)>
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 following general formula (3).

In the above general formula (3), R ⁷ is an aliphatic hydrocarbon group which may be substituted, or an aromatic hydrocarbon, which is substituted directly or via an oxygen atom, a nitrogen atom or a sulfur atom with a carbonyl carbon atom. Represents a group or a heterocyclic group, and R ⁸ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic group which may have a substituent. These aliphatic hydrocarbon group, aromatic hydrocarbon group, and heterocyclic group have the same meanings as those in General Formula (1). R ⁷ and R ⁸ may be connected to each other to form a cyclic structure. In the general formula (3), R ₈ is preferably an aromatic hydrocarbon group, and 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. R ⁷ is preferably an aliphatic hydrocarbon group directly bonded to a carbonyl carbon atom, particularly preferably a branched alkyl group or a cycloalkyl group.

  Specific examples of the compound represented by the general formula (3) are shown below, but the present invention is not limited to these exemplified compounds.

<Compound represented by formula (4)>
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 following general formula (4).

In the above general formula (4), 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 (1). Z ₂ may be a condensed ring.

  Specific examples of the compound represented by the general formula (4) are shown below, but the present invention is not limited to these exemplified compounds.

  As the compound represented by the general formula (4), N-hydroxysuccinimide, N-hydroxymaleic imide, N-hydroxyhexahydrophthalimide, and N-hydroxyphthalimide radical compounds are preferable.

<Compound represented by formula (5)>
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 following general formula (5).

In the above general formula (5), R ^{9 to} R ¹³ each independently represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic group which may have a substituent. These aliphatic hydrocarbon group, aromatic hydrocarbon group, and heterocyclic group have the same meanings as those in General Formula (1).

In the general formula (5), R ⁹ is preferably an aromatic hydrocarbon group, and 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. The R ¹⁰ to R ^13, preferably an alkyl group having 1 to 6 carbon atoms, a methyl group is particularly preferred.

  Specific examples of the compound represented by the general formula (5) are shown below, but the present invention is not limited to these exemplified compounds.

<Compound represented by formula (6)>
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 following general formula (6).

  In the said General formula (6), X is a structure which forms the principal chain of a polymer, and represents at least 1 sort (s) chosen from General formula (6-1)-(6-4) shown below.

R ^{21 to} R ²³ each independently represents an alkyl group having 1 to 3 carbon atoms, and examples thereof include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. From this viewpoint, a methyl group is preferable.

  Next, the following general formulas (6-1) to (6-4), which are structures forming the main chain of the polymer represented by X, will be further described.

In the above general formula (6-1), R ²⁴ represents a hydrogen atom or a methyl group.

In the general formula (6-2), R ²⁴ represents a hydrogen atom or a methyl group. R ²⁵ represents an alkylene group having 1 to 3 carbon atoms, for example, methylene group, ethylene group, ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane A -1,3-diyl group, a propane-2,2-diyl group, and the like can be mentioned. Among them, a methylene group is preferable from the viewpoint of easy synthesis.

In the general formula (6-3), R ^{26 to} R ²⁸ each independently represent a hydrogen atom or a methyl group.

In the general formula (6-4), R ^{26 to} R ²⁸ each independently represent a hydrogen atom or a methyl group. R ²⁹ represents an alkylene group having 1 to 3 carbon atoms. For example, methylene group, ethylene group, ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane A -1,3-diyl group, a propane-2,2-diyl group, and the like can be mentioned. Among them, a methylene group is preferable from the viewpoint of easy synthesis.

  Although the exemplary compounds 6-1 to 6-8 of the N-oxyl derivative represented by the general formula (6) are shown below, the present invention is not limited only to these exemplified compounds.

  For example compound 6-1, tetramethylanidin is used as a catalyst, and methyl vinyl ketone is Michael-added to 2-nitropropane to give 5-nitro-2-hexanone. Next, the obtained 5-nitro-2-hexanone is cyclized in water using ammonium chloride and zinc to obtain a cyclic nitrone compound. Ethynyl group is introduced into the obtained cyclic nitrone compound by Grignard reaction using ethynylmagnesium bromide in ether and further converted into a nitroxide radical by air oxidation using a copper catalyst. This is polymerized with a rhodium catalyst to give Exemplary Compound 6-1. Other exemplary compounds can also be obtained by a method similar to the above synthesis method. That is, after introducing an ethynyl group and a vinyl group into a cyclic nitrone compound by a Grignard reaction, a polymerizable monomer having a nitroxide radical is obtained by an oxidation reaction. This is polymerized with a suitable polymerization catalyst. In the case of an ethynyl group, it can be polymerized not only by a rhodium catalyst but also by a catalyst in which molybdenum, tungsten, niobium, tantalum chloride and an alkyltin compound, an alkylaluminum compound or the like are combined. In the case of a vinyl group, it can be polymerized by a catalyst in which a transition metal compound such as titanium tetrachloride, titanium trichloride, vanadium tetrachloride, or vanadium trichloride is combined with an organometallic compound of a typical metal such as triethylaluminum. The target N-oxyl derivative can be synthesized by appropriately changing the synthesis scheme, raw materials to be used, reaction conditions and the like, and combining known synthesis techniques.

  In the present invention, the N-oxyl derivative is also a polymer having a structure represented by the following general formulas (7) to (9) in the molecule.

<Compound represented by formula (7)>
The N-oxyl derivative according to the present invention is preferably a polymer having a structure represented by the following general formula (7) in the molecule.

In the first general formula (7), R ³⁰ represents an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a secondary butyl group, and a tertiary butyl group. Etc. R ³¹ represents a hydrogen atom or a methyl group.

  The compound represented by the general formula (7) preferably has a number average molecular weight of 500 or more, more preferably 5000 or more. This is because if the number average molecular weight is 500 or more, it is difficult to dissolve in the electrolyte solution, and if the number average molecular weight is 5000 or more, it is almost insoluble. The upper limit of the number average molecular weight is not particularly limited, but for the convenience of synthesis, a compound having a number average molecular weight of 5000000 or less, more preferably a number average molecular weight of 1000000 or less can be suitably used. The shape of the compound represented by the general formula (7) may be any of a chain shape, a branched shape, and a network shape. Moreover, the structure which bridge | crosslinked with the crosslinking agent may be sufficient.

  Although the exemplary compounds 7-1 to 7-8 of the N-oxyl derivative represented by the general formula (7) are shown below, the present invention is not limited only to these exemplified compounds.

  The compound represented by the general formula (7) according to the present invention can be synthesized, for example, according to the synthesis route described in [Chemical Formula 8] of JP-A-2007-35375.

<Compound represented by formula (8)>
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 following general formula (8).

In the general formula (8), R ³² represents an alkyl group having 1 to 4 carbon atoms, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, secondary butyl group, tertiary butyl group. Etc. R ³³ to R ³⁵ represents a hydrogen atom or a methyl group each independently.

  The compound represented by the general formula (8) preferably has a number average molecular weight of 500 or more, and more preferably 5000 or more. This is because if the number average molecular weight is 500 or more, it is difficult to dissolve in the electrolyte solution, and if the number average molecular weight is 5000 or more, it is almost insoluble. The upper limit of the number average molecular weight is not particularly limited, but for the convenience of synthesis, a compound having a number average molecular weight of 5000000 or less, more preferably a number average molecular weight of 1000000 or less can be suitably used. The shape of the compound represented by the general formula (8) may be any of a chain shape, a branched shape, and a network shape. Moreover, the structure which bridge | crosslinked with the crosslinking agent may be sufficient.

  Although the exemplary compounds 8-1 to 8-8 of the N-oxyl derivative represented by the general formula (8) are shown below, the present invention is not limited only to these exemplified compounds.

  The compound represented by the general formula (8) according to the present invention can be synthesized, for example, according to the synthesis route described in [Chemical Formula 9] of JP-A-2007-35375.

<Compound represented by formula (9)>
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 following general formula (9).

In the general formula (9), R ^{36 to} R ⁴³ each represents a substituted or unsubstituted alkyl group, and n represents an integer of 5 to 200.

R ^{36 to} R ⁴³ may be any substituted or unsubstituted alkyl group, and may be any of a chain, cyclic or branched alkyl group, preferably an alkyl having 1 to 10 carbon atoms, more preferably 1 to 4 carbon atoms. It is a group. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a t-butyl group. The alkyl group may be substituted with a halogen atom such as fluorine, chlorine, bromine or iodine, an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, a phosphorus atom, or a boron atom. n represents an integer of 5 to 200, preferably an integer of 10 to 100.

  Examples of the N-oxyl derivative represented by the general formula (9) are shown below, but the present invention is not limited only to the compounds exemplified here.

  The compound represented by the general formula (9) can be produced, for example, by subjecting a monomer having a norbornene skeleton to ring-opening polymerization using a metathesis catalyst such as a second generation Grubbs catalyst.

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

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

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

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

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

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

Examples of water-soluble compounds include proteins such as gelatin and gelatin derivatives, cellulose derivatives, natural compounds such as starch, gum arabic, dextran, pullulan, and carrageenan, and the like, polyvinyl alcohol, polyvinyl pyrrolidone, acrylamide polymers, and the like. Examples include synthetic polymer compounds such as derivatives. As gelatin derivatives, acetylated gelatin, phthalated gelatin, polyvinyl alcohol derivatives as terminal alkyl group-modified polyvinyl alcohol, terminal mercapto group-modified polyvinyl alcohol, and cellulose derivatives include hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose and the like. It is done. Furthermore, Research Disclosure and those described in pages (71) to (75) of JP-A No. 64-13546, US Pat. No. 4,960,681, JP-A No. 62-245260, etc. superabsorbent polymers described, namely -COOM or -SO ₃ M (M is a hydrogen atom or an alkali metal) homopolymer or a vinyl monomer together or with other vinyl monomers of the vinyl monomer having a (e.g., sodium methacrylate, Copolymers with ammonium acid, potassium acrylate, etc.) are also used. Two or more of these binders can be used in combination.

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

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

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

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

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

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

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

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

  In the display element of the present invention, it is desirable to carry out a curing reaction of the water-based compound with a curing agent during or after applying and drying the water mixture described above.

  Examples of the hardener used in the present invention include, for example, U.S. Pat. No. 4,678,739, column 41, 4,791,042, JP-A-59-116655, and 62-245261. No. 61-18942, 61-249054, 61-245153, JP-A-4-218044, and the like. More specifically, aldehyde hardeners (formaldehyde, etc.), aziridine hardeners, epoxy hardeners, vinyl sulfone hardeners (N, N'-ethylene-bis (vinylsulfonylacetamide) Ethane, etc.), N-methylol hardeners (dimethylolurea, etc.), boric acid, metaboric acid or polymer hardeners (compounds described in JP-A-62-234157). When gelatin is used as the aqueous compound, it is preferable to use a vinyl sulfone type hardener or a chlorotriazine type hardener alone or in combination. Moreover, when using polyvinyl alcohol, it is preferable to use boron-containing compounds such as boric acid and metaboric acid.

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

[Compound represented by formula (L)]
In the present invention, as the electrochromic compound, two types of compounds represented by the general formula (L) are used.

  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 is> N-Rl _4, an oxygen atom or a sulfur atom, Rl ₄ represents a hydrogen atom or a substituent.

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

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

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

The substituent represented by R1 ₂ or Rl ₃ is not particularly limited, and examples thereof include the substituents exemplified as the substituent on the aryl group of Rl ₁ . Rl ₂ and Rl ₃ are preferably an alkyl group, a cycloalkyl group, an aromatic group, or a heterocyclic group, which may have a substituent. Rl ₂ and Rl ₃ may be linked to each other to form a ring structure. The combination of Rl ₂ and Rl ₃ may be a phenyl group or a heterocyclic group, both of which may have a substituent, or Either one is a phenyl group or a heterocyclic group which may have a substituent, and the other is a combination of an alkyl group which may have a substituent.

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

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

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

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

In formula _{(L2), Rl 21, Rl} 22 is an aliphatic group, an aliphatic oxy group, an acylamino group, a carbamoyl group, an acyl group, a sulfonamido group, a sulfamoyl group, R1 ₂₃ aromatic group or an aromatic Represents a heterocyclic group, Rl ₂₄ represents a hydrogen atom, an aliphatic group, an aromatic group or an aromatic heterocyclic group; 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 and —Si (OR) ₃ ( R represents an alkyl group.

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

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

[Compound represented by formula (A) or (B)]
In the general formula (A) or the general formula (B) according to the present invention, Ra ₁ , Ra ₂ , Rb ₁ , Rb ₂ may each independently have a substituent, an aromatic group, an aromatic heterocyclic ring Represents an aliphatic group. Ra ₁ and Ra ₂ , Rb ₁ and Rb ₂ may be connected to each other to form a cyclic structure.

  Examples of the aromatic hydrocarbon group include a phenyl group and a naphthyl group. Examples of the aromatic heterocyclic group include a pyridyl group, a thiazolyl group, an oxazolyl group, an imidazolyl group, a furyl group, a pyrrolyl group, a pyrazinyl group, and a pyrimidinyl group. Group, pyridazinyl group, selenazolyl group, sulfolanyl group, piperidinyl group, pyrazolyl group, tetrazolyl group, morpholino group and the like. The aliphatic hydrocarbon group includes a chain and a cyclic group, and the chain includes a linear group and a branched group. Such aliphatic hydrocarbon groups include methyl, ethyl, vinyl, propyl, isopropyl, propenyl, butyl, iso-butyl, tert-butyl, pentyl, isopentyl, neopentyl, hexyl, iso-hexyl, cyclohexyl, cyclohexenyl, Examples include octyl, iso-octyl, cyclooctyl, 2,3-dimethyl-2-butyl and the like.

  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-hexadecanoyl Minophenyl 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, dodecyl Xy group etc.), 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) , Pyrrolylthio group, etc.), alkoxycarbonyl group (eg, methoxycarbonyl group, ethoxycarbonyl group, butoxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxy) Carbonyl group, etc.), sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenyl) Aminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, morpholinosulfonyl group, pyrrolidinosulfonyl group, etc.), urea Group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group, etc.), acyl group (for example, 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 Butylcarbonyloxy 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 Group, morpholinocarbonyl group, piperazinocarbonyl group, etc.), alkanesulfinyl group or arylsulfinyl group (for example, methanesulfinyl group, ethanesulfinyl group, butanesulfinyl group, cyclohexanesulfinyl group, 2-ethylhexanesulfinyl group, dodecane) Sulfinyl 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) , Ethylamino 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 (for example, trimethylsilyloxy group, tert-butyldimethylsilyloxy group, etc.), aminocarbonyloxy group (for example, N, N-dimethylcarbamoyloxy group, N, N-diethylcarbamoyloxy group, morpholinocarbonyloxy group, N N-di-n-octylaminocarbonyloxy group, Nn-octylcarbamoyloxy group, etc.), alkoxycarbonyloxy groups (for example, methoxycarbonyloxy group, ethoxycarbonyloxy group, tert-butoxycarbo group) Ruoxy group, n-octylcarbonyloxy group, etc.), aryloxycarbonyloxy group (for example, 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, etc.), phosphino group (eg dimethylphosphino group, diphenylphosphino group, methylphenoxyphosphino group etc.), phosphinyl group (eg phosphinyl group, dioctyloxyphosphinyl group) , Diethoxyphosphinyl group, etc.) Finyloxy group (eg, diphenoxyphosphinyloxy group, dioctyloxyphosphinyloxy group, etc.), phosphinylamino group (eg, 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 can be mentioned.

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

In the general formulas (A) and (B), Ra ₁ , Ra ₂ , Rb ₁ and Rb ₂ are preferably aromatic hydrocarbon groups or aromatic heterocyclic groups, and in particular, aromatics substituted with electron-withdrawing groups. An aromatic hydrocarbon group or an electron-deficient aromatic heterocyclic group is preferred. The electron-withdrawing group is an electron-withdrawing group having a Hammett's substituent constant σp value of 0 or more. Preferably, it is an electron withdrawing group having a σp value of 0.2 or more. The upper limit is preferably an electron withdrawing group of 1.0 or less. More preferably, it is an electron withdrawing group of 0.75 or less. Hammett's rule was found in 1935 by L. L. in order to quantitatively discuss the effect of substituents on the reaction or equilibrium of benzene derivatives. P. A rule of thumb proposed by Hammett, which is widely accepted today. Substituent constants determined by Hammett's rule include a σp value and a σm value, and these values are described in many general books. A. Dean, “Lange's Handbook of Chemistry”, 12th edition, 1979 (McGraw-Hill) and “Chemical Areas Extra”, 122, 96-103, 1979 (Nan-Edo). However, it does not mean that the values known in the literature described in these documents are limited to only certain substituents, and even if the values are unknown, as long as they are included in the range when measured based on Hammett's rule Of course included.

  Specific examples of the electron withdrawing group having a σp value of 0.20 or more include acyl group, acyloxy group, carbamoyl group, alkoxycarbonyl group, aryloxycarbonyl group, cyano group, nitro group, dialkylphosphono group, diarylphosphono group Group, diarylphosphinyl group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, sulfonyloxy group, acylthio group, sulfamoyl group, thiocyanate group, thiocarbonyl group, halogenated alkyl group, halogenated alkoxy group A halogenated aryloxy group, a halogenated alkylamino group, a halogenated alkylthio group, an aryl group substituted with another electron-withdrawing group having a σp value of 0.20 or more, a heterocyclic group, a halogen atom, an azo group, or The selenocyanate group It is.

  The electron-deficient aromatic heterocyclic group is preferably a group derived from a nitrogen-containing 6-membered ring such as a pyridine ring, a pyrazine ring, a pyrimidine ring, or a pyridazine ring.

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

  Specific examples of the compound represented by formula (B) are shown below, but the present invention is not limited to these exemplified compounds.

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

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

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

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

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

Specific examples of R ₁ to R ₄ are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, A linear or branched alkyl group such as nonyl, decyl, a cycloalkyl group such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, unsubstituted or halogen atom (F, Cl, Br, I), Hydroxyl group, lower alkoxy group (methoxy, ethoxy, propoxy, butoxy), carboxyl group, acetyl group, propanoyl group, thiol group, lower alkylthio group (methylthio, ethylthio, propylthio, butylthio), amino group, lower alkylamino group, di-lower Substitution such as alkylamino group An aryl group such as phenyl, naphthyl, toluyl and xylyl having 1 to 3 groups, and an aralkyl group such as benzyl can be exemplified. Specific examples of R ₅ include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl groups, and R ₆ represents methylene. And alkylene groups such as ethylene, propylene and butylene groups. Furthermore, specific examples of R ₇ include alkylene groups such as methylene, ethylene, propylene and butylene, and phenylene groups such as phenylene.

The counter anion represented by A ⁻ in the formula includes hexafluorophosphate, hexafluoroantimonate, hexafluoroarsenate, fluorosulfonate, tetrafluoroborate, nitrate, alkylsulfonate. Represents a fluorinated alkyl sulfonate or a hydrogen sulfate.

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

[Solid electrolyte, gel electrolyte]
The electrolyte of the present invention is not limited to a solution electrolyte composed of a solvent or an ionic liquid, but also a high-viscosity electrolyte or gel electrolyte (hereinafter referred to as a gel) containing a solid electrolyte or a polymer compound substantially free of a solvent. Electrolyte).

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

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

  As a method for forming a porous film, a sintering method (fusion method) (using fine pores formed between particles by adding polymer fine particles or inorganic particles to a binder or the like and partially fusing them), an extraction method ( After forming a constituent layer with a solvent-soluble organic substance or inorganic substance and a binder that does not dissolve in the solvent, the organic substance or inorganic substance is dissolved with the solvent to obtain pores), and the polymer is heated or degassed Known forming methods such as a foaming method in which foaming is performed, a phase change method in which a mixture of polymers is phase-separated by operating a good solvent and a poor solvent, and a radiation irradiation method in which pores are formed by radiating various types of radiation Can be used. Specifically, JP-A-10-30181, JP-A-2003-107626, JP-B-7-95403, JP-A-2635715, JP-A-2894523, JP-A-2987474, JP-A-3066426, and JP-A-3464513. No. 3,483,464, No. 3535942, No. 30622203, and the like.

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

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

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

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

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

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

〔electrode〕
In the display element of the present invention, it is preferable that at least one of the counter electrodes is a metal electrode. As the metal electrode, for example, known metal species such as platinum, gold, silver, copper, aluminum, zinc, nickel, titanium, bismuth, and alloys thereof can be used. The metal electrode is preferably a metal having a work function close to the redox potential of silver in the electrolyte. Above all, silver or a silver electrode having a silver content of 80% or more is advantageous for maintaining the reduced state of silver. Excellent in preventing dirt. As an electrode manufacturing method, an existing method such as an evaporation method, a printing method, an ink jet method, a spin coating method, or a CVD method can be used.

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

[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 in the display area of the display element is 1 to 40%, a practically sufficient strength as a display element can be obtained.

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

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

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

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

Example 1
<< Production of display element >>
(Preparation of electrolyte)
(Preparation of electrolyte 1)
Electrolyte solution 1 was obtained by dissolving 0.025 g of tetrabutylammonium perchlorate in 2.5 g of acetonitrile.

(Preparation of electrolyte 2)
Electrolyte solution 2 was obtained by dissolving 0.025 g of tetrabutylammonium perchlorate in 2.5 g of dimethyl sulfoxide.

(Preparation of electrolyte 3)
Electrolyte solution 3 was obtained by dissolving 0.025 g of spiro- (1,1 ′)-bipyrrolidinium tetrafluoroborate in 2.5 g of γ-butyrolactone.

(Preparation of electrolyte 4)
0.025 g of tetrafluoroboric acid spiro- (1,1 ′)-bipyrrolidinium and 0.025 g of compound (2-17) were dissolved in 2.5 g of γ-butyrolactone to obtain an electrolytic solution 4.

(Preparation of electrolyte 5)
0.025 g of spiro- (1,1 ′)-bipyrrolidinium tetrafluoroborate and 0.025 g of compound (2-26) were dissolved in 2.5 g of γ-butyrolactone to obtain an electrolytic solution 5.

[Production of electrodes]
(Production of electrode 1)
An ITO (Indium Tin Oxide) film having a pitch of 145 μm and an electrode width of 130 μm is formed on a glass substrate having a thickness of 1.5 mm and 2 cm × 4 cm according to a known method, and a transparent electrode (electrode 1) is formed. Obtained.

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

(Preparation of electrode 3)
Further, a titanium dioxide film having a thickness of 5 μm (about 4 to 10 particles having an average particle diameter of 17 nm was necked) was formed on the electrode 1 to obtain an electrode 3.

(Preparation of electrode 4)
The following ink liquid 1 was applied onto the electrode 3 at 120 dpi using an ink jet apparatus having a piezo-type head to produce the electrode 4. In addition, dpi as used in the field of this invention represents the number of dots per 2.54 cm.

(Preparation of electrodes 5-9)
Electrodes 5 to 9 were produced in the same manner as the electrode 4 except that the ink liquid 1 was changed to ink liquids 2 to 6.

(Production of electrode 10)
600 mg of carbon powder (conductivity imparting agent) and 100 mg of polyvinylidene fluoride (binder) were measured and mixed. 4 ml of acetylacetone was added here, and it stirred until it became a slurry form. The obtained slurry-like liquid was applied onto the electrode 2 with a doctor blade so that the film thickness after drying was 0.5 μm, and then dried at 80 ° C. for 3 minutes to obtain the electrode 10.

(Preparation of electrode 11)
300 mg of compound (A-29), 600 mg of carbon powder (conductivity imparting agent), and 100 mg of polyvinylidene fluoride (binder) were weighed and mixed. 4 ml of acetylacetone was added here, and it stirred until it became a slurry form. The obtained slurry-like liquid was applied on the electrode 2 with a doctor blade so that the film thickness after drying was 0.5 μm, and then dried at 80 ° C. for 3 minutes to obtain the electrode 11.

(Production of electrodes 12 to 15)
Electrodes 12 to 15 were produced in the same manner as the electrode 11 except that the compound (A-29) was changed to the compounds shown in Table 1.

[Preparation of ink liquid]
(Preparation of ink liquid 1)
Ink liquid 1 was prepared by dissolving compound EC-1 in ethanol to 3 mmol / L and compound EC-2 to 3 mmol / L.

(Preparation of ink liquid 2)
Ink liquid 2 was prepared by dissolving compound EC-3 in ethanol to 3 mmol / L and compound EC-4 to 3 mmol / L.

(Preparation of ink liquid 3)
Ink liquid 3 was prepared by dissolving compound EC-3 in ethanol at 3 mmol / L and compound (L1) at 3 mmol / L.

(Preparation of ink liquid 4)
The ink liquid 4 was prepared by dissolving the compound (L1) in ethanol to 3 mmol / L and the compound (L10) to 3 mmol / L.

(Preparation of ink liquid 5)
The ink liquid 5 was prepared by dissolving the compound (L17) in ethanol to 3 mmol / L and the compound (L7) to 3 mmol / L.

(Preparation of ink liquid 6)
The ink liquid 6 was prepared by dissolving the compound (L1) in ethanol to 3 mmol / L and the compound (L29) to 3 mmol / L.

[Production of display element]
(Preparation of display element 1)
After the periphery of the electrode 10 is edged with an olefin-based sealant containing glass spherical beads having an average particle size of 40 μm as a volume fraction of 10%, the striped electrodes are orthogonal to the electrode 10 and the electrode 4, respectively. The cells were bonded together and further heated and pressed to produce an empty cell. The electrolytic solution 1 was vacuum-injected into the empty cell, and the injection port was sealed with an epoxy-based ultraviolet curable resin to produce a display element 1.

(Production of display elements 2 to 20)
Display elements 2 to 20 were produced in the same manner as display element 1 except that the electrode configuration and the electrolyte were changed as shown in Table 1.

  The details of EC compounds other than the exemplified compounds described in Table 1 are as follows.

Compound EC-3: 1-Benzl-1 ′-(2-phosphoethyl) -4, 4′-bipyridinium dibromide
Compound EC-4: 1-Ethyl-1 ′-(3-phosphopropyl) -4, 4′-bipyridinium dichloride
<< Evaluation of display element >>
(Evaluation of display element 1)
[Display color evaluation]
When both electrodes of the manufactured display element 1 were connected to both terminals of the constant voltage power source and a constant voltage of +1 V was applied to the display side electrode for 0.5 seconds, the display color was switched from white to cyan. This indicates that only EC compound 1 is colored and EC compound 2 is not colored. Next, when a constant voltage of +2 V was applied to the display-side electrode for 0.5 seconds, the display color was switched from cyan to black. This indicates that the EC compound 2 is further colored red while the EC compound 1 is colored.

[Evaluation of black reflectance]
The reflectance immediately after the display element 1 is displayed in black by the above method is measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing Co., Ltd., and the average reflectance of 400 to 700 nm is an index of black reflectance. It was. Here, the smaller the obtained reflectance value is, the higher the black expression ability is.

[Evaluation of stability of black color fluctuation]
The chromaticity L ^* a ^* b ^* immediately after the display element 1 is displayed in black by the above method is measured with a spectrophotometer CM-3700d manufactured by Konica Minolta Sensing Co., Ltd., and the chromaticity L after being left for 10 minutes. ^* a ^* b ^* was measured with the same measuring device, a chromaticity difference ΔE was calculated, and ΔE was used as an indicator of the stability of black tone fluctuation. However, the display element 1 has a low memory property, and since it was almost completely erased 10 minutes after displaying black, ΔE could not be calculated.

(Evaluation of display element 2)
[Display color evaluation]
When both electrodes of the produced display element 2 were connected to both terminals of the constant voltage power source and a constant voltage of +2 V was applied to the electrode on the display side for 0.5 seconds, the display color switched from white to red. This indicates that only EC compound 3 is colored and EC compound 4 is not colored. Next, when a constant voltage of +3 V was applied to the display-side electrode for 0.5 seconds, the display color was switched from red to magenta, but black display was not possible.

(Evaluation of display element 3)
[Display color evaluation]
When both electrodes of the manufactured display element 3 were connected to both terminals of the constant voltage power source and a constant voltage of +2 V was applied to the display side electrode for 0.5 second, the display color was switched from white to red. This indicates that only EC compound 3 is colored and EC compound 2 is not colored. Next, when a constant voltage of +2.5 V was applied to the display-side electrode for 0.5 seconds, the display color was switched from red to black. This indicates that the EC compound (L10) is further cyan colored while the EC compound 1 is colored.

[Evaluation of black reflectance]
Similarly to the display element 1, the black reflectance of the display element 2 was evaluated.

[Evaluation of stability of black color fluctuation]
The chromaticity L ^* a ^* b ^* immediately after the display element 3 is displayed in black by the above method is measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing Co., Ltd., and the chromaticity L after being left for 10 minutes. ^* a ^* b ^* was measured with the same measuring device, a chromaticity difference ΔE was calculated, and ΔE was used as an indicator of the stability of black tone fluctuation. Here, the smaller the ΔE, the higher the stability of the black color tone fluctuation.

(Evaluation of display elements 4 to 11)
Except for changing the applied voltage to the voltage shown in Table 2, the display element 3 was evaluated in the same manner as the display element 3, and the display color evaluation of the display elements 4 to 11, and the black reflectance and the stability of black tone fluctuation were evaluated.

(Evaluation of display element 12)
[Display color evaluation]
When both electrodes of the display element 12 produced were connected to both terminals of the constant voltage power source and a constant voltage of +1.2 V was applied to the display side electrode for 0.5 seconds, the display color was switched from white to blue. This indicates that only the EC compound 17 is colored and the EC compound (L7) is not colored. Next, when a constant voltage of +1.8 V was applied to the electrode on the display side for 0.5 seconds, the display color was switched from blue to black. This indicates that the EC compound (L2) is further colored yellow while the EC compound (L17) is colored.

[Evaluation of black reflectance]
Similarly to the display element 3, the black reflectance of the display element 12 was evaluated.

[Evaluation of stability of black color fluctuation]
In the same manner as the display element 3, the stability of the black color tone fluctuation of the display element 12 was evaluated.

(Evaluation of display element 13)
[Display color evaluation]
When both electrodes of the manufactured display element 13 were connected to both terminals of the constant voltage power source and a constant voltage of +2.5 V was applied to the display side electrode for 1 second, the display color was switched from white to black. This indicates that both the EC compound (L1) and the EC compound (L29) are colored. Next, when a constant voltage of −0.8 V was applied to the display-side electrode for 0.5 seconds, the display color was switched from black to red. This indicates that the cyan coloration of the EC compound (L29) was erased while the red coloration of the EC compound (L1) was maintained.

[Evaluation of black reflectance]
Similarly to the display element 3, the black reflectance of the display element 13 was evaluated.

[Evaluation of stability of black color fluctuation]
In the same manner as the display element 3, the stability of the black color tone fluctuation of the display element 13 was evaluated.

(Evaluation of display elements 14 to 20)
Except for changing the applied voltage to the voltage described in Table 2, the display color evaluation of the display elements 14 to 20 and the black reflectance and the stability of the black tone variation were evaluated in the same manner as the display element 13.

  Table 2 shows the configuration and evaluation results of each display element obtained as described above.

  As is apparent from the results shown in Table 2, it can be seen that the display element having the configuration defined in the present invention has higher black display contrast and smaller black display color tone variation than the comparative example.

Claims (10)

There are an electrolyte and a white scatterer between the counter electrodes, and two kinds of compounds represented by the following general formula (L) are immobilized on at least one counter electrode, and a voltage V ₁ (V ), The first type of the compound represented by the general formula (L) is colored to display red, green or blue, and the first type of the compound represented by the general formula (L) In the state where is colored, a voltage V ₂ (V) is further applied between the counter electrodes to color the second type compound represented by the general formula (L), thereby displaying black. The display element, wherein the voltage V ₁ and the voltage V ₂ satisfy a relationship of V ₂ > V ₁ > 0.

[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 other counter electrode different from the counter electrode on which the compound represented by the general formula (L) is immobilized is represented by a compound represented by the following general formula (A) or the following general formula (B). The display element according to claim 1, wherein the compound is immobilized.

[Wherein, Ra ₁ , Ra ₂ , Rb ₁ and Rb ₂ each independently represent an aromatic hydrocarbon group, an aromatic heterocyclic group or an aliphatic hydrocarbon group which may have a substituent. Ra ₁ and Ra ₂ , Rb ₁ and Rb ₂ may be connected to each other to form a cyclic structure. ] The Ra ₁ and Ra ₂ in the general formula (A) and the Rb ₁ and Rb _{2 in} the general formula (B) are respectively an aromatic hydrocarbon group or an aromatic heterocyclic group. The display element as described in. In the general formula (A), Ra ₁ and Ra ₂ and Rb ₁ and Rb _{2 in} the general formula (B) are each an aromatic hydrocarbon group substituted with an electron-withdrawing group or an electron-deficient aromatic heterocyclic ring. The display element according to claim 2, wherein the display element is a base. The display element according to claim 1, wherein the electrolyte contains an N-oxyl derivative. There are an electrolyte and a white scatterer between the counter electrodes, and at least one counter electrode has two kinds of compounds represented by the following general formula (L) immobilized thereon, and a voltage V ₃ (V ) To display black by coloring the two types of compounds represented by the general formula (L), and applying the voltage V ₄ (V) between the counter electrodes allows the two types to be displayed. By decoloring any one of the compounds represented by the general formula (L), red, green or blue is displayed, and the voltage V ₃ and the voltage V ₄ are V ₃ >0> V _4. A display element characterized by satisfying the relationship:

[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 other counter electrode different from the counter electrode on which the compound represented by the general formula (L) is immobilized is represented by a compound represented by the following general formula (A) or the following general formula (B). The display element according to claim 6, wherein the compound is immobilized.

[Wherein, Ra ₁ , Ra ₂ , Rb ₁ and Rb ₂ each independently represent an aromatic hydrocarbon group, an aromatic heterocyclic group or an aliphatic hydrocarbon group which may have a substituent. Ra ₁ and Ra ₂ , Rb ₁ and Rb ₂ may be connected to each other to form a cyclic structure. ] The Ra ₁ and Ra ₂ in the general formula (A) and the Rb ₁ and Rb _{2 in} the general formula (B) are respectively an aromatic hydrocarbon group or an aromatic heterocyclic group. The display element as described in. In the general formula (A), Ra ₁ and Ra ₂ and Rb ₁ and Rb _{2 in} the general formula (B) are each an aromatic hydrocarbon group substituted with an electron-withdrawing group or an electron-deficient aromatic heterocyclic ring. The display element according to claim 7, wherein the display element is a group. The display element according to claim 6, wherein the electrolyte contains an N-oxyl derivative.