JP2010190945A - Display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display element simple in member configuration, drivable at low voltage and excelling in reflectance stability in repetitive driving. <P>SOLUTION: The display element has an electrolyte between counter electrodes provided on support bodies respectively. At least one of the counter electrodes is an electrode having layer configuration of three or more layers, wherein two of respective junctions of the laminated configuration are Schottky junctions, and a Schottky barrier of the Schottky junction on the side closer to the support body is high toward the electrolyte from the support body, while a Schottky barrier of the Schottky junction on the side closer to the electrolyte is high toward the support body from the electrolyte. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

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

  As a means for browsing such electronic information, a conventional liquid crystal display or CRT, and in recent years, a light emitting type such as an organic EL display is mainly used. In particular, when the electronic information is document information, it is relatively long time. It is necessary to keep an eye on the browsing means over time, and these actions are hardly human-friendly means. In general, light-emitting displays are known to suffer from eye fatigue due to flickering, inconvenient to carry, limited reading posture, need to focus on a static screen, and increase power consumption when read for a long time. .

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

  That is, the method using a polarizing plate such as a reflective liquid crystal has a low reflectance of about 40%, which makes it difficult to display white, and it is difficult to say that many of the manufacturing methods used to manufacture the constituent members are simple. In addition, the polymer dispersed liquid crystal requires a high voltage and utilizes the difference in refractive index between organic substances, so that the resulting image has insufficient contrast. In addition, the polymer network type liquid crystal has problems such as a high driving voltage and a complicated TFT circuit required to improve the memory performance. In addition, a display element based on electrophoresis requires a high voltage of 10 V or more, and there is a concern about durability due to electrophoretic particle aggregation.

  As a display method for eliminating the drawbacks of each of the above-described methods, an electrodeposition method (hereinafter, abbreviated as ED method) using dissolution precipitation of metal or metal salt is known. The ED method can be driven at a low voltage of 3 V or less, has advantages such as a simple cell configuration, excellent black-white contrast and black quality, and various methods have been disclosed (for example, Patent Document 1). -3)).

  As a result of examining the techniques disclosed in each of the above patent documents in detail, the present inventor has found that there is a problem in the stability of the reflectance when it is repeatedly driven, and solves this problem. As a means for improving the electrolysis driving stability of a metal dissolution precipitation type electrochemical display element, there is a technique of adding a redox buffer such as ferrocene to the electrolytic solution (see, for example, Patent Document 4).

  The technique described in Patent Document 4 is a technique intended to improve driving stability by redox buffer being oxidized and reduced at the non-observation side electrode. To improve driving stability, the redox buffer is used. It was found that it was necessary to increase the amount of addition sufficiently, in which case it was accompanied by a decrease in memory performance and a decrease in rewriting speed.

U.S. Pat. No. 4,240,716 Japanese Patent No. 3428603 JP 2003-241227 A JP 2007-508587 A

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

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

  1. A display element having an electrolyte between counter electrodes provided on a support, wherein at least one of the counter electrodes has a layer structure of three or more layers, and two of the junctions in the stacked structure are shot. The Schottky barrier of the Schottky junction on the side close to the support is a key junction, and the Schottky barrier of the Schottky junction on the side close to the electrolyte rises from the support to the electrolyte. A display element characterized by having an electrode that rises toward the body.

  2. 2. The display element according to 1 above, wherein the electrolyte contains a silver salt compound.

  3. 3. The display element according to 1 or 2 above, wherein each layer forming the Schottky junction is made of a different material.

  4). 4. The display element according to 3 above, wherein the different material is a metal oxide or a metal nitride.

  5. 5. The display element according to any one of 1 to 4, wherein a layer closer to the support among the layers forming the Schottky junction is a layer containing indium oxide.

  6). Any one of 1 to 5 above, wherein the layer close to the electrolyte among the layers forming the Schottky junction is a layer made of titanium nitride, tantalum nitride, or a composite material of titanium nitride and tantalum nitride. The display element according to item.

  7). 7. The display element according to any one of 1 to 6, wherein an intermediate layer of the layers forming the Schottky junction is a layer made of titanium oxide or zinc oxide.

  According to the present invention, it is possible to provide a display element that has a simple member structure, can be driven at a low voltage, has little characteristic change in repeated driving, and has a high rewriting speed.

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

  As a result of intensive studies in view of the above problems, the inventor of the present invention has a simple display element characterized in that the non-observation side electrode has a laminated structure of three or more layers having two Schottky barriers. It has been found that a display element that can be driven with a member structure and low voltage and has excellent reflectance stability in repeated driving can be realized, and the present invention has been achieved.

  That is, according to the present invention, the non-observation side electrode has a three-layered structure made of different materials, so that a Schottky barrier is created at the interface between the layers, and the entire non-pixel side electrode has two Schottky barriers. Technology. Therefore, by adopting the electrode configuration of the present invention, it is possible to provide a rectifying action both in the case of driving by applying a positive voltage between the counter electrodes and in the case of driving by applying a negative voltage. When the display element is not driven, electrons between the Schottky junctions are held by the non-observation side electrode, and when the display element is driven, the electrons held by the non-observation side electrode are taken out and observed. This is a technique that can be used for the dissolution and precipitation reaction of the metal on the side, and the driving stability is improved.

  Details of the present invention will be described below.

[Basic structure of display element]
In the display element of the present invention, the display portion is provided with one corresponding counter electrode. For an electrode (also referred to as a display-side electrode or an observation-side electrode) that is one of the counter electrodes close to the observation part, a transparent electrode such as an ITO electrode is used as the other electrode (also referred to as a non-display-side electrode or a non-observation-side electrode). Is provided with a three-layer laminated film according to the present invention. Between the observation-side electrode and the non-observation-side electrode, there is an electrolyte containing a metal salt compound and a white scatterer. By applying positive and negative voltages between the counter electrodes, white display and black display Can be switched reversibly.

[Schottky junction, Schottky barrier]
The electrode according to the present invention has a laminated structure of three or more metal oxides or metal nitrides having different work functions, and has a Schottky barrier at each adjacent interface. The Schottky junction of the present invention refers to an interface having a Schottky barrier. For example, in the case of a three-layer structure, when a layer closer to the support, an intermediate layer, and a layer closer to the electrolytic solution are used, the Schottky barrier increases from the layer closer to the support toward the intermediate layer. By combining the three layers so that the Schottky barrier increases from the layer close to the intermediate layer to the intermediate layer, the rectifying action can be achieved both when electrons enter and exit the electrodes of the stacked structure of the present invention. Will show.

  The height of the Schottky barrier can be measured by a method obtained from current-voltage characteristics, a method obtained from capacitance-voltage characteristics, a method obtained from optical response, or the like.

[Material for forming Schottky junction]
The material constituting the electrode according to the present invention is preferably composed of different materials for each layer. Examples of the combination of different materials include indium oxide doped with tin oxide in the first layer, titanium oxide or zinc oxide in the second layer, and tantalum nitride or a composite material of titanium nitride and tantalum nitride in the third layer. Examples of a method for forming each layer constituting the electrode according to the present invention include a sputtering method, a vacuum evaporation method, an ink jet method, a spin coating method, a printing method, and the like. A preferable formation method is a sputtering method or a vacuum evaporation method. .

  The thickness of each layer constituting the electrode according to the present invention is preferably several tens to several hundreds of nm for the first layer, several to several tens of nm for the second layer, and several tens to several hundreds of nm for the third layer. . In particular, the thickness of the second layer is important in determining the magnitude of the rectifying action. If it is too thin, the rectifying action is insufficient. If it is too thick, the applied voltage for driving the display element becomes too high. Thickness is present.

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

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

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

Specific examples of the salts include halogen ions, SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , PF _{^{6 -, AsF 6 -, CH}} 3 COO -, CH 3 (C 6 H 4) SO 3 -, and _{(C 2 F 5 SO 2)} 3 C - Li salt having a counter anion selected from, Na salt or K salt is mentioned.

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 ⁻ A quaternary ammonium salt having a counter anion selected from CH ₃ COO ⁻ , CH ₃ (C ₆ H ₄ ) SO ₃ ⁻ , and (C ₂ F ₅ SO ₂ ) ₃ C ⁻ , specifically, (CH ₃ ) ₄ 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 , and a compound represented by the following formula can be given.

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 ⁻ , A phosphonium salt having a counter anion selected from CH ₃ COO ⁻ , CH ₃ (C ₆ H ₄ ) SO ₃ ⁻ , and (C ₂ F ₅ SO ₂ ) ₃ C ^— , specifically, (CH ₃ ) _{4 PBF 4, (C 2 H 5} ) 4 PBF 4, (C 3 H 7) 4 PBF 4, include _{(C 4 H 9) 4 PBF} 4 and the like. Moreover, these mixtures can also be used suitably.

The supporting electrolyte of the present invention is preferably a quaternary ammonium salt, particularly preferably a quaternary spiro ammonium salt. The _ClO ⁴ as counter anion ^{_{-, BF 4 -, CF 3}} SO 3 -, (C 2 F 5 SO 2) 2 N -, PF 6 - are preferable, and BF ₄ ^- is preferable.

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

  In the case of a solid electrolyte, the following compounds showing electron conductivity and ion conductivity can be contained in the electrolyte.

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

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

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

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

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

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

Formula (1): 0 ≦ [X] / [Metal] ≦ 0.1
The halogen atom as used in the field of this invention means an iodine atom, a chlorine atom, a bromine atom, and a fluorine atom. When [X] / [Metal] is greater than 0.1, X ⁻ → X ₂ is generated during the oxidation-reduction reaction of the metal, and X ₂ easily cross-oxidizes with the deposited metal to dissolve the deposited metal. Therefore, the molar concentration of halogen atoms is preferably as low as possible relative to the molar concentration of metallic silver. In the present invention, 0 ≦ [X] / [Metal] ≦ 0.001 is more preferable. In the case of adding halogen ions, the halogen species preferably have a total molar concentration of [I] <[Br] <[Cl] <[F] from the viewpoint of improving memory properties.

[Compound represented by General Formula (G1) or (G1)]
In the present invention, a silver salt solvent can be used to promote dissolution and precipitation of metal salts (particularly silver salts). The silver salt solvent may be any compound that can solubilize silver in the electrolyte. For example, silver or a compound containing silver is solubilized by coexisting with a compound containing a chemical structural species that interacts with silver, such as a coordinate bond with silver or a weak covalent bond with silver. It is common to use a means for converting to an object. As the chemical species, a halogen atom, a mercapto group, a carboxyl group, an imino group, and the like are known. It is characterized by low influence on coexisting compounds and high solubility in solvents.

  In particular, it is preferable to contain at least one compound represented by the following general formula (G1) or general formula (G2).

[Compound represented by General Formula (G1) or General Formula (G2)]
General Formula _{(G1) Rg 11 -S-Rg} 12
[Wherein Rg ₁₁ and Rg ₁₂ each represents a substituted or unsubstituted hydrocarbon group. These hydrocarbon groups may contain one or more nitrogen atoms, oxygen atoms, phosphorus atoms, sulfur atoms, and halogen atoms, and Rg ₁₁ and Rg ₁₂ may be linked to each other to form a cyclic structure. ]

[Wherein, M represents a hydrogen atom, a metal atom or quaternary ammonium. Z represents an atomic group necessary for constituting a nitrogen-containing heterocyclic ring. n represents an integer of 0 to 5, Rg ₂₁ represents a substituent, and when n is 2 or more, each Rg ₂₁ may be the same or different, and may be connected to each other to form a condensed ring. It may be formed. ]
In the general formula (G1), Rg ₁₁ and Rg ₁₂ each represent a substituted or unsubstituted hydrocarbon group, which includes an aromatic straight chain group or a branched group. Further, these hydrocarbon groups may contain one or more nitrogen atoms, oxygen atoms, phosphorus atoms, and sulfur atoms, and Rg ₁₁ and Rg ₁₂ may be connected to each other to take a cyclic structure. However, when a ring containing an S atom is formed, an aromatic group is not taken.

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

  Hereinafter, specific examples of the compound represented by the general formula (G1) according to the present invention will be shown, but the present invention is not limited only to these exemplified compounds.

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

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

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

In the general formula (G2), M represents a hydrogen atom, a metal atom, or quaternary ammonium. Z represents an atomic group necessary for constituting a nitrogen-containing heterocycle. n represents an integer of 0 to 5, Rg ₂₁ represents a substituent, and when n is 2 or more, each Rg ₂₁ may be the same or different, and may be connected to each other to form a condensed ring. It may be formed.

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

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

The substituents represented by Rg ₂₁ of the general formula (G2), not particularly limited, but include for example substituents such as the following.

  Hydrogen atom, halogen atom (eg, fluorine atom, chlorine atom, bromine atom, iodine atom), alkyl group (eg, methyl, ethyl, propyl, i-propyl, butyl, t-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl) Octyl, dodecyl, hydroxyethyl, methoxyethyl, trifluoromethyl, benzyl, etc.), aryl groups (eg, phenyl, naphthyl, etc.), alkylcarbonamide groups (eg, acetylamino, propionylamino, butyroylamino, etc.), aryl Carboxamide groups (eg, benzoylamino), alkylsulfonamide groups (eg, methanesulfonylamino group, ethanesulfonylamino group, etc.), arylsulfonamide groups (eg, benzenesulfonylamino group, toluenesulfonylamino) Group), alkoxy group, aryloxy group (for example, phenoxy), alkylthio group (for example, methylthio, ethylthio, butylthio, etc.), arylthio group (for example, phenylthio group, tolylthio group, etc.), alkylcarbamoyl group (for example, methylcarbamoyl group) Dimethylcarbamoyl, ethylcarbamoyl, diethylcarbamoyl, dibutylcarbamoyl, piperidylcarbamoyl, morpholylcarbamoyl, etc.), arylcarbamoyl groups (eg, phenylcarbamoyl, methylphenylcarbamoyl, ethylphenylcarbamoyl, benzylphenylcarbamoyl, etc.), carbamoyl groups, alkylsulfurates Famoyl groups (eg methylsulfamoyl, dimethylsulfamoyl, ethylsulfamoyl, diethylsulfamoyl, dibu Sulfamoyl, piperidylsulfamoyl, morpholylsulfamoyl, etc.), arylsulfamoyl groups (eg, phenylsulfamoyl, methylphenylsulfamoyl, ethylphenylsulfamoyl, benzylphenylsulfamoyl, etc.), sulfamoyl groups , A cyano group, an alkylsulfonyl group (eg, methanesulfonyl group, ethanesulfonyl group, etc.), an arylsulfonyl group (eg, phenylsulfonyl, 4-chlorophenylsulfonyl, p-toluenesulfonyl, etc.), an alkoxycarbonyl group (eg, methoxycarbonyl, Ethoxycarbonyl, butoxycarbonyl etc.), aryloxycarbonyl group (eg phenoxycarbonyl etc.), alkylcarbonyl group (eg acetyl, propionyl, butyroyl etc.), a A reelcarbonyl group (for example, benzoyl group, alkylbenzoyl group, etc.), an acyloxy group (for example, acetyloxy, propionyloxy, butyroyloxy, etc.), a carboxyl group, a carbonyl group, a sulfonyl group, an amino group, a hydroxy group, or a heterocyclic group (for example, , Oxazole ring, thiazole ring, triazole ring, selenazole ring, tetrazole ring, oxadiazole ring, thiadiazole ring, thiazine ring, triazine ring, benzoxazole ring, benzthiazole ring, indolenine ring, benzselenazole ring, naphthothiazole ring , Triazaindolizine ring, diazaindolizine ring, tetraazaindolizine ring group, etc.). These substituents further include those having a substituent.

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

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

〔solvent〕
Solvents are generally used in electrochemical cells and batteries, and dissolve various additives such as electrochromic compounds used in the present invention, metal salt compounds that are reversibly dissolved and precipitated by electrochemical redox reactions, and promoters. Any solvent can be used.

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

  Furthermore, room temperature molten salts can also be used as solvents. The room temperature molten salt is a salt composed of ion pairs that are melted at room temperature (that is, in a liquid state) consisting only of ion pairs that do not contain a solvent component, and usually has a melting point of 20 ° C. or lower, A salt consisting of an ion pair that is liquid at a temperature above. The room temperature molten salt can be used alone or in combination of two or more.

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

  In the present invention, particularly preferably used solvents are compounds represented by the following general 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).

[Wherein, 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. ]

[Wherein, Rs ₂₁ and Rs ₂₂ each represents an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group, or an alkoxy group. ]
First, the detail of the compound represented by general formula (S1) is demonstrated.

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

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

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

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

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

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

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

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

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

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

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

(Porous white scattering layer)
In the present invention, a porous white scattering layer can be provided from the viewpoint of further enhancing display contrast and white display reflectance.

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

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

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

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

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

  Polymers dispersed in aqueous solvents 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.

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

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

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

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

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

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

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

  In the present invention, the medium for applying the water mixture of the water-based compound and the white pigment may be at any position as long as it is on the component between the counter electrodes of the display element, but on the electrode surface of at least one of the counter electrodes. It is preferable to give to.

  As a method for applying to a medium, for example, a coating method, a liquid spraying method, a spraying method via a gas phase, a method of flying droplets using vibration of a piezoelectric element, for example, a piezoelectric inkjet head, Examples thereof include a bubble jet (registered trademark) type ink jet head that causes droplets to fly using a thermal head that uses bumping, and a spray type that sprays liquid by air pressure or liquid pressure.

  As a coating method, it can select suitably from a well-known coating method. For example, air doctor coater, blade coater, rod coater, knife coater, squeeze coater, impregnation coater, reverse roller coater, transfer roller coater, curtain coater, double roller coater, slide hopper coater, gravure coater, kiss roll coater, bead coater, Examples include cast coaters, spray coaters, calendar coaters, and extrusion coaters.

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

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

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

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

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

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

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

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

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

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

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

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

  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 996 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]
[Display side transparent substrate]
The substantially transparent substrate used in the present invention is a substrate having a transmittance for visible light of at least 50% or more.

  Examples of such transparent substrates include polyester (for example, polyethylene terephthalate), polyimide, polymethyl methacrylate, polystyrene, polypropylene, polyethylene, polyamide, nylon, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyether sulfone, and silicone resin. Polymer films such as polyacetal resins, fluororesins, cellulose derivatives, polyolefins, plate-like substrates, glass substrates and the like are preferably used.

[Counter substrate]
In addition to the transparent substrate mentioned as the display-side transparent substrate, an opaque substrate such as an inorganic substrate such as a metal substrate or a ceramic substrate can also be used.

[electrode]
[Display side transparent electrode]
The transparent electrode is not particularly limited as long as it is transparent and conducts electricity. For example, Indium Tin Oxide (ITO: Indium Tin Oxide), Indium Zinc Oxide (IZO: Indium Zinc Oxide), Fluorine Doped Tin Oxide (FTO), Indium Oxide, Zinc Oxide, Platinum, Gold, Silver, Rhodium, Copper, Examples thereof include chromium, carbon, aluminum, silicon, amorphous silicon, and BSO (Bismuth Silicon Oxide).

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

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

[Grid electrode (auxiliary electrode)]
An auxiliary electrode can be attached to at least one of the counter electrodes according to the present invention.

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

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

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

  As a method of forming the auxiliary electrode, a known method can be used. For example, patterning may be performed by a photolithography method, a printing method, an ink jet method, electrolytic plating or electroless plating, or a method of forming a pattern by exposing and developing using a silver salt photosensitive material.

  Although the line width and line interval of the auxiliary electrode pattern of the present invention may be arbitrary values, it is necessary to increase the line width in order to increase the conductivity. On the other hand, when an auxiliary electrode is attached to the transparent electrode, from the viewpoint of visibility, the area coverage of the auxiliary electrode viewed from the display element observation side is preferably 30% or less, and more preferably 10% or less.

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

(Electrode manufacturing method)
A known method can be used to form the transparent electrode and the metal auxiliary electrode. For example, mask deposition may be performed on the substrate by sputtering or the like, or patterning may be performed by photolithography after the entire surface is formed.

  Electrodes can also be formed by electrolytic plating, electroless plating, printing methods, and ink jet methods.

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

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

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

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

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

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

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

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

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

  Sealing agent is for sealing so that it does not leak outside and is also called sealing agent. Epoxy resin, urethane resin, acrylic resin, vinyl acetate resin, ene-thiol resin, silicon resin, modified resin A curing type such as a polymer resin, such as a thermosetting type, a photocurable type, a moisture curable type, and an anaerobic curable type can be used.

  The columnar structure provides strong self-holding (strength) between the substrates, for example, a columnar body, a quadrangular columnar body, an elliptical columnar body, a trapezoidal array arranged in a predetermined pattern such as a lattice arrangement. A columnar structure such as a columnar body can be given. Alternatively, stripes arranged at predetermined intervals may be used. This columnar structure is not a random array, but can be properly maintained at intervals of the substrate, such as an evenly spaced array, an array in which the interval gradually changes, and an array in which a predetermined arrangement pattern is repeated at a constant period. The arrangement is preferably considered so as not to disturb the display. If the ratio of the area occupied by the columnar structure in the display 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, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

<< Production of display element >>
(Preparation of electrolyte)
(Preparation of electrolyte 1)
In 2.5 g of the exemplary compound (S1-4), 0.1 g of silver p-toluenesulfonate, 0.2 g of the exemplary compound (G2-12) and 0.025 g of bis (trifluoromethylsulfonyl) imide lithium It was made to melt | dissolve and the electrolyte solution 1 was obtained.

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

(Preparation of electrode 2)
On the electrode 1, a Cr thin film was formed by sputtering to have an average film thickness of 5 nm, and further a gold thin film was formed to have an average film thickness of 20 nm, whereby an electrode 2 was produced.

(Preparation of electrode 3)
A titanium dioxide thin film was formed on the electrode 1 so as to have an average film thickness of 20 nm by a sputtering method, whereby an electrode 3 was produced.

(Preparation of electrode 4)
A zinc oxide thin film was formed on the electrode 1 so as to have an average film thickness of 20 nm by a sputtering method, whereby an electrode 4 was produced.

(Preparation of electrode 5)
On the electrode 1, a titanium dioxide thin film is formed by sputtering to have an average film thickness of 20 nm, and a titanium nitride thin film is further formed by sputtering to have an average film thickness of 50 nm. did.

(Preparation of electrode 6)
A titanium dioxide thin film is formed on the electrode 1 by sputtering to have an average film thickness of 20 nm, and further a tantalum nitride thin film is formed by sputtering to have an average film thickness of 50 nm. did.

(Preparation of electrode 7)
On the electrode 1, a titanium dioxide thin film is formed by sputtering to have an average film thickness of 20 nm, and further, a composite comprising 50% ratio of titanium nitride and tantalum nitride to have an average film thickness of 50 nm by sputtering. A thin film was formed to produce an electrode 7.

(Preparation of electrode 8)
On the electrode 1, a titanium dioxide thin film is formed so as to have an average film thickness of 10 nm by a sputtering method, and further a composite composed of 50% ratio of titanium nitride and tantalum nitride so that the average film thickness is 50 nm by a sputtering method. A thin film was formed to produce an electrode 8.

(Preparation of electrode 9)
On the electrode 1, a titanium dioxide thin film is formed by sputtering to have an average film thickness of 5 nm, and further a composite comprising 50% ratio of titanium nitride and tantalum nitride to have an average film thickness of 50 nm by sputtering. A thin film was formed to produce an electrode 9.

(Production of electrode 10)
On the electrode 1, a titanium dioxide thin film is formed by sputtering to have an average film thickness of 30 nm, and further a composite comprising 50% ratio of titanium nitride and tantalum nitride to have an average film thickness of 50 nm by sputtering. A thin film was formed to produce the electrode 10.

(Preparation of electrode 11)
On the electrode 1, a titanium dioxide thin film is formed by sputtering to have an average film thickness of 50 nm, and further a composite comprising 50% ratio of titanium nitride and tantalum nitride to have an average film thickness of 50 nm by sputtering. A thin film was formed to produce the electrode 11.

(Preparation of electrode 12)
A zinc oxide thin film is formed on the electrode 1 so as to have an average film thickness of 20 nm by a sputtering method, and a titanium nitride thin film is further formed by a sputtering method so that the average film thickness is 50 nm. did.

(Preparation of electrode 13)
A zinc oxide thin film is formed on the electrode 1 so that the average film thickness is 20 nm by sputtering, and further a tantalum nitride thin film is formed so that the average film thickness is 50 nm by sputtering. did.

(Preparation of electrode 14)
A zinc oxide thin film is formed on the electrode 1 by sputtering to have an average film thickness of 20 nm, and further a composite comprising 50% ratio of titanium nitride and tantalum nitride to have an average film thickness of 50 nm by sputtering. A thin film was formed to produce an electrode 14.

(Preparation of electrode 15)
A zinc oxide thin film is formed on electrode 1 so as to have an average film thickness of 10 nm by a sputtering method, and further a composite comprising 50% ratio of titanium nitride and tantalum nitride so that the average film thickness is 50 nm by a sputtering method. A thin film was formed to produce the electrode 15.

(Preparation of electrode 16)
On the electrode 1, a zinc oxide thin film is formed by sputtering to have an average film thickness of 5 nm, and further a composite comprising 50% ratio of titanium nitride and tantalum nitride to have an average film thickness of 50 nm by sputtering. A thin film was formed to produce the electrode 16.

(Preparation of electrode 17)
A zinc oxide thin film is formed on the electrode 1 by sputtering to have an average film thickness of 30 nm, and further a composite comprising 50% ratio of titanium nitride and tantalum nitride to have an average film thickness of 50 nm by sputtering. A thin film was formed to produce an electrode 17.

(Preparation of electrode 18)
A zinc oxide thin film is formed on electrode 1 so as to have an average film thickness of 50 nm by a sputtering method, and further a composite comprising 50% ratio of titanium nitride and tantalum nitride so that the average film thickness is 50 nm by a sputtering method. A thin film was formed to produce an electrode 18.

[Evaluation of Schottky barrier]
The Schottky barrier was confirmed by measuring the current-voltage characteristics of the electrode obtained above. Confirm that electrode 2 does not have a Schottky barrier, electrodes 3 and 4 have one Schottky barrier, and electrodes 5 to 18 meet the conditions of the present invention with two Schottky barriers did.

[Preparation of titanium dioxide dispersion]
Kuraray Poval PVA235 (manufactured by Kuraray Co., Ltd., polyvinyl alcohol resin) was added to the water / ethanol mixed solution so as to have a solid content concentration of 2% by mass, dissolved by heating, and then titanium dioxide CR-90 made by Ishihara Sangyo Co., Ltd. Was dispersed with an ultrasonic disperser so as to be 20% by mass to obtain a titanium dioxide dispersion.

[Production of display element]
(Preparation of display element 1)
On the electrode 1, the above titanium dioxide dispersion was screen-printed so that the average film thickness after drying was 20 μm, then dried at 50 ° C. for 30 minutes to evaporate the solvent, and then in an atmosphere at 85 ° C. The electrode 1a which dried for 1 hour and formed the porous white scattering layer was produced. Next, the peripheral portion of the electrode 1a in the vicinity of 2 cm × 2 cm is trimmed with an olefin-based sealant containing glass spherical beads having an average particle diameter of 40 μm as a volume fraction, and then a porous white scattering layer is formed. The electrode 1a and the electrode 1 on which the porous white scattering layer was not formed were bonded so as to be orthogonal to form a notch portion of the injection port, and then 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 21)
Display elements 2 to 18 were produced in the same manner as display element 1 except that the types of electrodes were changed to the combinations shown in Table 1.

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

  As is apparent from the results shown in Table 1, it can be seen that the display element satisfying the configuration of the present invention has improved reflectance stability when it is repeatedly driven as compared with the comparative example.

Claims (7)

  A display element having an electrolyte between counter electrodes provided on a support, wherein at least one of the counter electrodes has a layer structure of three or more layers, and two of the junctions in the stacked structure are shot. The Schottky barrier of the Schottky junction on the side close to the support is a key junction, and the Schottky barrier of the Schottky junction on the side close to the electrolyte rises from the support to the electrolyte. A display element characterized by having an electrode that rises toward the body.   The display element according to claim 1, wherein the electrolyte contains a silver salt compound.   3. The display element according to claim 1, wherein each layer forming the Schottky junction is made of a different material.   The display element according to claim 3, wherein the different material is a metal oxide or a metal nitride.   5. The display element according to claim 1, wherein a layer close to the support among the layers forming the Schottky junction is a layer containing indium oxide.   6. The layer close to the electrolyte among the layers forming the Schottky junction is a layer made of titanium nitride, tantalum nitride, or a composite material of titanium nitride and tantalum nitride. Item 1. A display element according to item 1.   The display element according to claim 1, wherein an intermediate layer of the layers forming the Schottky junction is a layer made of titanium oxide or zinc oxide.