JP2008026605A - Electrochromic display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrochromic display element having excellent whiteness during white display and display speed. <P>SOLUTION: In the electrochromic display element having counter electrodes, at least one porous layer A containing titanium oxide to which an electrochromic dyestuff is adsorbed and at least one porous layer B containing tin oxide, a gel-shaped electrolyte containing a metal oxide having an average particle diameter larger than that of the titanium oxide to which the electrochromic dyestuff is adsorbed is included between the counter electrodes. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrochromic display element excellent in whiteness and display speed during white display.

  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 that compensates for these drawbacks, a reflection type display that uses external light and does not consume power for image retention (memory type) is known, but has sufficient performance for the following reasons. It's hard to say.

  That is, the method using a polarizing plate such as a reflective liquid crystal has a low reflectance of about 40% and is difficult to display white, and many of the production methods used for producing the constituent members are not easy. In addition, the polymer dispersed liquid crystal requires a high voltage and utilizes the difference in refractive index between organic substances, so that the resulting image has insufficient contrast. In addition, the polymer network type liquid crystal has problems such as a high voltage and a 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.

  On the other hand, the electrochromic display element can be driven at a low voltage of 3 V or less, but the color quality of black or color (yellow, magenta, cyan, blue, green, red, etc.) is not sufficient, and the memory property is low. In order to ensure, there is a concern that the display cell requires a complicated film configuration such as a vapor deposition film.

  As a method for improving the problems of these electrochromic display methods, for example, a color is reversibly generated by a porous layer and at least one of an oxidation reaction and a reduction reaction between two conductive substrates, at least one of which is transparent. Alternatively, an electrochromic display device using an electrochromic element intervening with an electrolyte containing an electrochromic dye to be erased is disclosed, and the structure is simple, bright and easy to see, and power consumption can be reduced. (For example, refer to Patent Documents 1 and 2).

As a result of proceeding with the examination in more detail, the present inventor produced a full-color electrochromic display element by the method disclosed in Patent Documents 1 and 2 and evaluated the display characteristics. As a result, the required performance for the display element increased. However, it has been found that the whiteness at the time of white display and the display speed at the time of image display have not yet reached satisfactory quality.
International Publication No. 2004/068231 Pamphlet International Publication No. 2004/0667673 Pamphlet

  This invention is made | formed in view of the said subject, The objective is to provide the electrochromic display element which is excellent in the whiteness and display speed at the time of white display.

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

  1. A counter electrode; a porous layer A containing titanium oxide adsorbing at least one layer of electrochromic dye; and a porous layer B containing at least one layer of tin oxide, and the electrochromic layer between the counter electrodes An electrochromic display element comprising a gel electrolyte containing a metal oxide having an average particle size larger than that of titanium oxide on which a dye is adsorbed.

  2. 2. The electrochromic display element according to 1 above, wherein an average primary particle size of a main component of the metal oxide contained in the gel electrolyte is 200 nm or more and 1000 nm or less.

  3. 3. The electrochromic display element as described in 1 or 2 above, wherein the metal oxide contained in the gel electrolyte is titanium dioxide.

  4). 4. The electrochromic display element as described in any one of 1 to 3 above, wherein the gel electrolyte contains a butyral resin.

  5. 5. The electrochromic display element as described in 4 above, wherein an average polymerization degree of the butyral resin is 300 or more and 1000 or less.

  6). 6. The electrochromic display element according to any one of 1 to 5, wherein a mass ratio of a solvent constituting the gel electrolyte and the metal oxide is in a range of 10: 1 to 1: 1. .

  7). 6. The electrochromic display element according to any one of 1 to 5, wherein a mass ratio of a solvent constituting the gel electrolyte and the metal oxide is in a range of 20: 1 to 2: 1. .

  8). 8. The electrochromic display element according to any one of 1 to 7, wherein the electrochromic dye is represented by the following general formula (1).

[Wherein, R ¹ represents — (CH ₂ ) _m — (where m represents 0 or an integer of 1 to 10), an arylene group having up to 14 carbon atoms, and a heteroarylene group, each carbon atom A branched alkylene group, an alkenylene group, or a cycloalkylene group of up to several tens, and each arylene group, heteroarylene group, branched alkylene group, branched alkenylene group, or cycloalkylene group is optionally -P (O) (OH) ₂ group - (CH _{2) n} - may have through a group. Moreover, you may substitute arbitrarily. Here, n represents 0 or an integer of 1 to 10.

R ² is a group represented by R ³ R ⁴ , wherein R ³ represents — (CH ₂ ) p— (wherein p represents 0 or an integer of 1 to 10), and R ⁴ Represents a -P (O) (OH) ₂ group, or an aryl group or heteroaryl group having up to 14 carbon atoms, a branched alkyl group, an alkenyl group, or a cycloalkyl group each having up to 10 carbon atoms.

X ⁻ represents an ion that neutralizes charge.

However, when R ² is — (CH ₂ ) ₂ —P (O) (OH) ₂ , R ¹ is not — (CH ₂ ) _m — (m is 2 or 3). In addition, when R ² is a phenyl group, R ¹ is not — (CH ₂ ) _m — (m is 2). ]
9. The electrochromic display element according to any one of 1 to 7, wherein the electrochromic dye is represented by the following general formula (2).

[Wherein, R ₁ represents a substituted or unsubstituted aryl group, and R ₂ and R ₃ each represent a hydrogen atom or a substituent. X represents> N—R ₄ , an oxygen atom or a sulfur atom, and R ₄ represents a hydrogen atom or a substituent. ]
10. The porous layer A containing titanium oxide adsorbed with the electrochromic dye or the porous layer B containing tin oxide has a thickness of 1.0 μm or more and 5.0 μm or less. The electrochromic display element according to any one of 1 to 9.

  11. 11. The electrochromic display element according to any one of 1 to 10, wherein a plurality of the electrochromic display elements are stacked to display a plurality of colors.

  12 The porous layer A containing titanium oxide on which different electrochromic dyes are adsorbed is arranged in a pattern between the counter electrodes to display a plurality of colors. Electrochromic display element.

  13. The electrochromic according to any one of 1 to 11, wherein a plurality of kinds of electrochromic dyes are adsorbed on the counter electrode by a porous layer containing the same titanium oxide to display a plurality of colors. Display element.

  14 14. The electrochromic display element according to any one of 1 to 13, wherein the gel electrolyte is formed by screen printing using a gel electrolyte.

  15. 15. The electrochromic display element as described in any one of 1 to 14, wherein at least one counter electrode is formed on a plastic substrate.

  According to the present invention, an electrochromic display element excellent in whiteness and display speed during white display can be provided.

  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 has found that a counter electrode, a porous layer A containing titanium oxide adsorbed with at least one electrochromic dye, and a porous material containing at least one tin oxide layer. And a gel electrolyte containing a metal oxide having an average particle size larger than that of titanium oxide having the electrochromic dye adsorbed between the counter electrodes. It has been found that an electrochromic display element excellent in whiteness and display speed at the time of white display can be realized by the display element, and as soon as the present invention has been achieved.

  Details of the present invention will be described below.

  One feature of the electrochromic display element of the present invention is that it has a porous layer A containing titanium oxide on which at least one electrochromic dye is adsorbed.

[Electrochromic dye]
First, the details of the electrochromic dye according to the present invention will be described.

  The electrochromic dye according to the present invention may be any compound that exhibits electrochromic properties.

  Specifically, JP-A-62-297382, JP-A-62-228689, JP-A-3-54528, JP-A-5-224242, JP-A-5-98251, JP-A-2004-01729, JP-A-2000-2000. -241835, the pigment | dye described in the international publication 2004/066773 pamphlet etc. can be mentioned.

  For example, the compound represented by the following general formula (1) is mentioned.

In the general formula (1), R ¹ is — (CH ₂ ) _m — (where m represents 0 or an integer of 1 to 10), an arylene group having up to 14 carbon atoms, a heteroarylene group, Represents a branched alkylene group, alkenylene group, or cycloalkylene group having up to 10 atoms, and each arylene group, heteroarylene group, branched alkylene group, branched alkenylene group, or cycloalkylene group is optionally -P (O) ( OH) ₂ group may be present through a — (CH ₂ ) _n — group. Moreover, you may substitute arbitrarily. Here, n represents 0 or an integer of 1 to 10.

R ² is a group represented by R ³ R ⁴ , wherein R ³ represents — (CH ₂ ) p— (where p represents 0 or an integer of 1 to 10), and R ⁴ represents , -P (O) (OH) ₂ group, an aryl group having up to 14 carbon atoms, a heteroaryl group, a branched alkyl group having up to 10 carbon atoms, an alkenyl group, or a cycloalkyl group.

X ⁻ represents an ion that neutralizes charge.

However, when R ² is — (CH ₂ ) ₂ —P (O) (OH) ₂ , R ¹ is not — (CH ₂ ) _m — (m is 2 or 3). In addition, when R ² is a phenyl group, R ¹ is not — (CH ₂ ) _m — (m is 2).

In addition, the arylene group, heteroarylene group having up to 14 carbon atoms, branched alkylene group, branched alkenylene group, or cycloalkylene group each having up to 10 carbon atoms represented by R ¹ can be optionally substituted. These groups may be substituted by one or two or more, and when a plurality of substituents are substituted, they may be different from each other or the same substituent.

  Examples of these substituents include the following groups.

  Lower alkyl group, lower alkenyl group, phenyl substituted-lower alkyl group, diphenyl substituted-lower alkyl group, phenyl group, phenoxy group, lower alkanoyloxy group, halogen atom, amino group, cyano group, nitro group, lower alkylamino group, Di (lower alkyl) amino group, phenylamino group, lower alkanoylamino group, benzoylamino group, lower alkylsulfonylamino group, phenylsulfonylamino group, lower alkanoyl group, benzoyl group, carboxyl group, lower alkoxycarbonyl group, carbamoyl group, N-lower alkylcarbamoyl group, N, N-di- (lower alkyl) carbamoyl group, ureido group, N-lower alkylureido group, lower alkylsulfonyl group, phenylsulfonyl group, hydroxyl group, lower alkoxy group, Mino group, lower alkylamino group, di (lower alkyl) amino group, lower alkoxy group substituted by halogen atom, carboxyl group or lower alkoxycarbonyl group, alkoxy group having 3 to 7 carbon atoms, divalent methylenedi An oxy group etc. are mentioned.

  In addition, the phenyl groups mentioned above, and the phenyl groups contained in the benzoyl group, phenylamino group, etc. are all substituted with lower alkyl groups, lower alkoxy groups, halogen atoms, hydroxy groups, nitro groups, etc. Also good.

The aryl group, heteroaryl group, branched alkyl group, alkenyl group, cycloalkyl group and the like represented by R ⁴ may also be unsubstituted, but one or more may be selected depending on the group defined as the substituent for R ^1. It may be substituted as described above.

In the general formula (1), as a preferable compound, R ¹ is — (CH ₂ ) _m — (where m represents 1, 2, 3), a phenyl group (— (CH ₂ ) _n — group). P is substituted with a -P (O) (OH) ₂ group, and n represents 1 or 2, and in R ² (represented by R ³ R ⁴ ), R ₃ is — (CH ₂ ) _p — (wherein p represents 0, 1, 2, 3), R ⁴ is unsubstituted phenyl or naphthyl, an alkyl group having 1 to 4 carbon atoms, or a halogen atom A phenyl or naphthyl group mono-, di- or tri-substituted by a cyano group, a nitro group, a phenoxy group or a benzoyl group.

X ⁻ is Cl ⁻ , Br ⁻ , ClO ₄ ⁻ , PF ₆ ⁻ , BF ₄ ⁻ , C ₂ F ₆ NO ₄ S ₂ ⁻ or CF ₃ SO ₃ ⁻ , and particularly preferably Cl ⁻ , PF ₆ ⁻ .

In the general formula (1), as a preferable compound, R ¹ is — (CH ² ) _m — (where m represents 1, 2, 3), a phenyl group (— (CH ₂ ) _n — The p-position is substituted with a -P (O) (OH) ₂ group through a group, and n represents 1 or 2, and in R ² (represented by R ³ R ⁴ ), R ³ Represents — (CH ₂ ) _p — (wherein p represents 0, 1, 2, 3), R ⁴ represents a —P (O) (OH) ₂ group, X ⁻ represents Cl ⁻ , Br ⁻ , ClO ₄ ⁻ , PF ₆ ⁻ , BF ₄ ⁻ , C ₂ F ₆ NO ₄ S ₂ ⁻ or CF ₃ SO ₃ ⁻ , particularly preferably Cl ⁻ and PF ₆ ⁻ .

  Examples of preferable compounds among the above are listed below.

(1) 1-phosphonoethyl-1 '-(3-propylphenyl) -4,4'-bipyridinium dichloride (2) 1-phosphonoethyl-1'-(3-propylphenyl) -4,4'- Bipyridinium bis-hexafluorophosphate (3) 1-phosphonoethyl-1 '-(2,4,6-trimethylphenyl) -4,4'-bipyridinium dichloride (4) 1-phosphonoethyl-1'-( 2,4,6-trimethylphenyl) -4,4'-bipyridinium bis-hexafluorophosphate (5) 1-phosphonoethyl-1 '-(naphthyl) -4,4'-bipyridinium dichloride (6) 1- Phosphoethyl-1 '-(4-cyanonaphthyl) -4,4'-bipyridinium dichloride (7) 1-phospho Ethyl-1 '-(4-methylphenyl) -4,4'-bipyridinium dichloride (8) 1-phosphonoethyl-1'-(4-cyanophenyl) -4,4'-bipyridinium dichloride (9) 1- Phosphoethyl-1 ′-(4-fluorophenyl) -4,4′-bipyridinium dichloride (10) 1-phosphonoethyl-1 ′-(4-phenoxyphenyl) -4,4′-bipyridinium dichloride (11) 1-phosphonoethyl-1 '-(4-t-butylphenyl) -4,4'-bipyridinium dichloride (12) 1-phosphonoethyl-1'-(2,6-dimethylphenyl) -4,4 ' -Bipyridinium dichloride (13) 1-phosphonoethyl-1 '-(3,5-dimethylphenyl) -4,4'-bi Lidinium dichloride (14) 1-phosphonoethyl-1 '-(4-benzophenone) -4,4'-bipyridinium dichloride (15) 1-phosphonobenzyl-1'-(3-propylphenyl) -4,4 ' -Bipyridinium dichloride (16) 1-phosphonobenzyl-1 '-(3-propylphenyl) -4,4'-bipyridinium bis-hexafluorophosphate (17) 1-phosphonobenzyl-1'-(phosphonoethyl) ) -4,4'-bipyridinium dichloride (18) 1-phosphonobenzyl-1 '-(2,4-dinitrophenyl) -4,4'-bipyridinium dichloride (19) 1-phosphonobenzyl-1'-( 2,4-dinitrophenyl) -4,4'-bipyridinium bis-hex Fluorophosphate (20) 1-phosphonobenzyl-1 ′-(4-phenoxyphenyl) -4,4′-bipyridinium dichloride (21) 1-phosphonobenzyl-1 ′-(4-phenoxyphenyl) -4, 4'-bipyridinium bis-hexafluorophosphate (22) 1-phosphonobenzyl-1 '-(4-fluorophenyl) -4,4'-bipyridinium dichloride (23) 1-phosphonobenzyl-1'-(4 -Methylphenyl) -4,4'-bipyridinium dichloride (24) 1-phosphonobenzyl-1 '-(2,4,6-trimethylphenyl) -4,4'-bipyridinium dichloride (25) 1-phosphonobenzyl -1 '-(benzyl) -4,4'-bipyridinium dichloride 26) 1-phosphonobenzyl-1 '-(naphthyl) -4,4'-bipyridinium dichloride (27) 1-phosphonobenzyl-1'-(phenyl) -4,4'-bipyridinium dichloride (28) 1- Phosphobenzyl-1 ′-(4-cyanophenyl) -4,4′-bipyridinium dichloride (29) 1-phosphonobenzyl-1 ′-(4-benzophenone) -4,4′-bipyridinium dichloride (30) 1 -Phosphonobenzyl-1 '-(4-cyanophenyl) -4,4'-bipyridinium dichloride (31) 1-phosphonobenzyl-1'-(2,6-dimethylphenyl) -4,4'-bipyridinium dichloride (32) 1-phosphonobenzyl-1 '-(3,5-dimethylphenyl) -4, 4'-bipyridinium dichloride (33) 1-phosphonobenzyl-1 '-(2,4,6-trimethylphenyl) -4,4'-bipyridinium trifluoromethanesulfonimide As a specific method for producing these compounds, For example, it is described in the pamphlet of International Publication No. 2004/066773.

  Moreover, as a preferable electrochromic compound in this invention, the compound represented with General formula (2) below is mentioned.

In the general formula (2), R ₁ represents a substituted or unsubstituted aryl group, and R ₂ and R ₃ each represent a hydrogen atom or a substituent. X represents> N—R ₄ , an oxygen atom or a sulfur atom, and R ₄ represents a hydrogen atom or a substituent.

In the above general formula (2), R ₁ represents a substituted or unsubstituted aryl group, and R ₂ and R ₃ each represent a hydrogen atom or a substituent, but the substitution represented by R ₁ , R ₂ , or R ₃ Specific examples of the group include, for example, an alkyl group (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, etc.), cycloalkyl group (for example, cyclohexyl group, cyclopentyl group). Etc.), alkenyl group, cycloalkenyl group, alkynyl group (for example, propargyl group), glycidyl group, acrylate group, methacrylate group, aromatic group (for example, phenyl group, naphthyl group, anthracenyl group, etc.), heterocyclic group ( For example, pyridyl group, thiazolyl group, oxazolyl group, imidazolyl group, furyl group, pyrrolyl group, pyrazinyl group, pyrimidinyl , Pyridazinyl group, selenazolyl group, sriphoranyl group, piperidinyl group, pyrazolyl group, tetrazolyl group, etc.), alkoxy group (for example, methoxy group, ethoxy group, propyloxy group, pentyloxy group, cyclopentyloxy group, hexyloxy group, cyclohexyloxy group) Group), aryloxy group (for example, phenoxy group, etc.), alkoxycarbonyl group (for example, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, etc.), aryloxycarbonyl group (for example, phenyloxycarbonyl group, etc.) ), Sulfonamide group (for example, methanesulfonamide group, ethanesulfonamide group, butanesulfonamide group, hexanesulfonamide group, cyclohexanesulfonamide group, benzenesulfonamide group, etc.), Rufamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, phenylaminosulfonyl group, 2-pyridylaminosulfonyl group), urethane group ( For example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, phenylureido group, 2-pyridylureido group, etc.), acyl group (for example, acetyl group, propionyl group, butanoyl group, hexanoyl group, cyclohexanoyl group) Group, benzoyl group, pyridinoyl group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentyl) Aminocarbonyl group, cyclohexylaminocarbonyl group, phenylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), acylamino group (eg, acetylamino group, benzoylamino group, methylureido group, etc.), amide group (eg, acetamido group, propion) Amide group, butanamide group, hexaneamide group, benzamide group, etc.), sulfonyl group (eg, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, phenylsulfonyl group, 2-pyridylsulfonyl group, etc.), sulfonamide Group (for example, methylsulfonamide group, octylsulfonamide group, phenylsulfonamide group, naphthylsulfonamide group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, Tilamino 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), oxamoyl group, and the like can be given. Further, these groups may be further substituted with these groups.

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

R ₂ and R ₃ are preferably an alkyl group, a cycloalkyl group, an aromatic group, or a heterocyclic group, more preferably one of R ₂ and R ₃ is a phenyl group, the other is an alkyl group, and more preferably R ₂ and R ₃ are both phenyl groups.

X is preferably> N—R ₄ . R 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.

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

(Porous layer)
One feature of the electrochromic display element of the present invention is that it has a porous layer A containing titanium oxide adsorbed with an electrochromic dye and a porous layer B containing tin oxide.

  In the present invention, a highly reversible electrochromic material is applied at an applied voltage of about 3 V or less by including titanium oxide in which an electrochromic dye is adsorbed in the porous layer A and tin oxide in the porous layer B. Coloring and decoloring of the dye can be performed.

The porous layer A and the porous layer B according to the present invention can be formed by binding or contacting a plurality of fine particles of titanium oxide or tin oxide. The average primary particles of the titanium oxide or tin oxide fine particles are preferably 5 nm to 100 nm, more preferably 20 nm to 80 nm. The specific surface area of titanium oxide or tin oxide fine particles is preferably from ^{1 × 10 -3 ~1 × 10 2} m 2 / g by a simple BET method, and more preferably 1 × 10 ^-2 ~10m ² / g It is. The shape of the titanium oxide or tin oxide fine particles may be any shape such as an indefinite shape, a needle shape, or a spherical shape.

  The thickness of the porous layer A and the porous B according to the present invention is preferably 1 μm or more and 5 μm or less. In the porous layer A containing titanium oxide to which the electrochromic dye is adsorbed, if it is less than 1 μm, a sufficient amount of electrochromic dye cannot be adsorbed, resulting in a decrease in contrast, and if it exceeds 5 μm, the resolution is decreased. Invite disadvantage.

  As a method of forming or binding titanium oxide or tin oxide according to the present invention, a known sol-gel method or sintering method can be employed. For example, 1) Journal of the Ceramic Society of Japan, 102, 2, p200 (1994), 2) Journal of the Ceramic Industry Association, 90, 4, p157, 3) J. Org. of Non-Cryst. Solids, 82, 400 (1986) and the like. In addition, a method is used in which titanium oxide dendrimer particles prepared by a vapor phase method are dispersed on a solution, applied onto a substrate, dried at a temperature of about 120 to 150 ° C., and the solvent is removed to obtain a porous layer. You can also.

  In addition, a low temperature process such as a chemical solution deposition method described in “Low Resistance / Low Temperature / Large Area Film Formation Technology of Transparent Conductive Film” (July 2005, ISBN4-86104-078-7 C3058 published by the Japan Society of Technology) In particular, when the porous layer is connected to a part of the pixel circuit through the transparent electrode, there is little damage to the pixel pixel circuit, and display between pixels in a display display in which the pixel circuit is integrated There is an advantage that variation can be reduced.

  The fine particles of titanium oxide or tin oxide are preferably bound, and preferably have a resistance of 0.1 g or more, preferably 1 g or more with a continuous load type surface property measuring instrument (for example, a scratch tester).

  Porous as used in the present invention refers to a penetrating state in which a porous layer is disposed, a potential difference is applied between the counter electrodes, an electrochromic reaction can be caused, and ionic species can move in the porous layer. .

[Gel electrolyte]
The electrochromic display element of the present invention is characterized by containing a gel electrolyte containing a metal oxide having an average particle size larger than that of titanium oxide in which the electrochromic dye is adsorbed between the counter electrodes.

  Electrolytes are usually classified into liquid electrolytes and polymer electrolytes. The polymer electrolyte is further classified into a solid electrolyte substantially composed of a solid compound, a gel electrolyte composed of a polymer compound and a liquid electrolyte. From the viewpoint of fluidity, the solid electrolyte has substantially no fluidity, while the gel electrolyte has fluidity intermediate between the liquid electrolyte and the solid electrolyte.

  Therefore, the gel electrolyte referred to in the present invention refers to a liquid electrolyte having a high viscosity at room temperature and fluidity. For example, an electrolyte having a viscosity at 25 ° C. of 100 mPa · s or more and 1000 mPa · s or less. Refers to liquid. It should be noted that the gel electrolyte according to the present invention does not necessarily have the property of causing a sol-gel change with temperature.

  In the present invention, as a method for bringing the electrolyte into a gel state, each of the solvent constituting the electrolyte and its addition amount, the metal oxide type and its addition amount, the addition of a resin material, the addition of a thickener, etc. Although it can be obtained by selecting and combining means, in the present invention, it is particularly preferable to add a resin material and use a butyral resin as the resin material.

<Electrolyte material>
In the display element of the present invention, the gel electrolyte can contain the following compounds. KCl, KI, KBr, etc. as potassium compounds, LiBF ₄ , LiClO ₄ , LiPF ₆ , LiCF ₃ SO ₃ etc. as lithium compounds, tetraethylammonium perchlorate, tetrabutylammonium perchlorate, tetraethylammonium borofluoride as tetraalkylammonium compounds And tetrabutylammonium borofluoride and tetrabutylammonium halide. Moreover, the molten salt electrolyte composition described in JP-A-2003-187881 paragraphs [0062] to [0081] can also be preferably used. Furthermore, a compound that becomes a redox pair such as I ⁻ / I ₃ ⁻ , Br ⁻ / Br ₃ ⁻ , and quinone / hydroquinone can be used.

<Electrolyte added solvent>
In the display element of the present invention, a solvent can be used as long as the electrolyte can maintain a gel state. 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 that 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), Y. 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) can be mentioned <Butyral Resin>
In the gel electrolyte according to the present invention, it is preferable to use a butyral resin as the resin material from the viewpoint of obtaining a gel state.

  The butyral resin used in the present invention can be used by being dissolved in an electrolyte solvent so that the ratio of the electrolyte solvent to the butyral resin is in the range of 20: 1 to 2: 1 in terms of mass ratio.

  Moreover, it is preferable that the butyral resin used by this invention exists in the range of 300-1000 average degree of polymerization.

  Examples of the butyral resin applicable in the present invention include # 3000-1, # 3000-2, # 3000-4, # 3000-K, # 4000-2, # 5000-A, manufactured by Denki Kagaku Kogyo Co., Ltd. Examples thereof include # 5000-D, # 6000-C, # 6000-AS, # 6000-CS, and S-LEC series manufactured by Sekisui Chemical Co., Ltd.

<Metal oxide with gel electrolyte added>
In the present invention, the gel electrolyte contains a metal oxide having an average particle size larger than that of titanium oxide on which the electrochromic dye contained in the porous layer A is adsorbed.

  Examples of the metal oxide 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, and magnesium phosphate. Magnesium hydrogen phosphate, alkaline earth metal salts, talc, kaolin, zeolite, acid clay, glass, organic compounds such as polyethylene, polystyrene, acrylic resin, ionomer, ethylene-vinyl acetate copolymer resin, benzoguanamine resin, urea-formalin resin Melamine-formalin resin, polyamide resin, etc. may be used alone or in a composite mixture, or in a state having voids that change the refractive index in the particles.

In the present invention, titanium dioxide is preferably used among the above metal oxides, and in particular, titanium dioxide surface-treated with inorganic oxides (Al ₂ O ₃ , AlO (OH), SiO _2, etc.) is more preferably used.

  In the titanium dioxide used in the present invention, the ratio of the gel electrolyte solvent to titanium dioxide is preferably in the range of 10: 1 to 1: 1 by mass ratio.

<Thickener added with gel electrolyte>
In the display element of the present invention, a thickener can be used for the gel electrolyte. For example, gelatin, gum arabic, poly (vinyl alcohol), hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate butyrate, Poly (vinyl pyrrolidone), 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 ( Vinylidene chloride), poly (epoxides), poly (carbonates), poly (vinyl acetate), cellulose esters, poly (amides), hydrophobic transparent binders such as polyvinyl butyral, cellulose acetate, cellulose acetate butyrate, polyester , 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.

[Counter electrode]
Examples of the counter electrode applicable to the electrochromic display element of the present invention include a metal electrode and a transparent 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. 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.

  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.

  As the counter electrode according to the present invention, it is preferable to use a transparent electrode in order to obtain a sufficiently large color gamut for full color display. In particular, an ITO electrode is preferable from the viewpoint of light transmittance and resistance.

[Other additives]
Examples of the constituent layers of the electrochromic 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. Additives such as chemical sensitizers, noble metal sensitizers, photosensitive dyes, supersensitizers, couplers, high boiling point solvents, antifoggants, stabilizers, development inhibitors, and bleach accelerators in the following research disclosures Agent, fixing accelerator, color mixing inhibitor, formalin scavenger, toning agent, hardener, surfactant, thickener, plasticizer, slip agent, ultraviolet absorber, irradiation prevention dye, filter light absorption dye, anticorrosive Additives listed as agents, polymer latex, heavy metals, antistatic agents, matting agents, and the like can be included as necessary.

  More specifically, these additives described above are described in detail in Research Disclosure (hereinafter abbreviated as RD), Volume 176 Item / 17643 (December 1978), Volume 184, Item / 18431 (August 1979), Volume 187. 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.

[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 out. It is also called sealing agent. Epoxy resin, urethane resin, acrylic resin, vinyl acetate resin, ene-thiol resin, silicone 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.

[Screen printing]
In the present invention, a sealant, a columnar structure, an electrode pattern, and the like can be formed by a screen printing method. In the screen printing method, a screen on which a predetermined pattern is formed is placed on an electrode surface of a substrate, and a printing material (a composition for forming a columnar structure, such as a photocurable resin) is placed on the screen. Then, the squeegee is moved at a predetermined pressure, angle, and speed. Thereby, the printing material is transferred onto the substrate through the pattern of the screen. Next, the transferred material is heat-cured and dried. When the columnar structure is formed by the screen printing method, the resin material is not limited to a photocurable resin, and for example, a thermosetting resin such as an epoxy resin or an acrylic resin or a thermoplastic resin can also be used. As thermoplastic resins, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, polymethacrylate resin, polyacrylate resin, polystyrene resin, polyamide resin, polyethylene resin, polypropylene resin, fluororesin, polyurethane resin , Polyacrylonitrile resin, polyvinyl ether resin, polyvinyl ketone resin, polyether resin, polyvinyl pyrrolidone resin, saturated polyester resin, polycarbonate resin, chlorinated polyether resin and the like. The resin material is preferably used in the form of a paste by dissolving the resin in an appropriate solvent.

  After the columnar structure or the like is formed on the substrate as described above, a spacer is provided on at least one of the substrates as desired, and the pair of substrates are overlapped with the electrode formation surfaces facing each other to form an empty cell. . A pair of stacked substrates is heated while being pressed from both sides, whereby the display cells are obtained. In order to obtain a display element, an electrolyte composition may be injected between substrates by a vacuum injection method or the like. Alternatively, when the substrates are bonded together, the electrolyte composition may be dropped on one substrate, and the liquid crystal composition may be sealed simultaneously with the bonding of the substrates.

[Configuration of full-color display element]
When performing full color display using the electrochromic display element of the present invention,
1. A method of laminating electrochromic display elements that develop and erase colors in different colors such as yellow, magenta, cyan, red, green, blue, black,
2. A method of patterning a porous portion adsorbing an electrochromic dye that develops and decolors in different colors on a flat surface,
3. Examples include a method of adsorbing a plurality of types of electrochromic dyes that develop and decolor in different color tones to a porous layer between a pair of counter electrodes.

  In the case of 3, the electrochromic dye must have a threshold value. As a method for providing the threshold value, voltage or charge amount in the color developing or decoloring direction or voltage hysteresis in the color developing or decoloring direction is set for each dye. The method of changing to is mentioned.

[Display element driving method]
The active matrix driving according to the present invention is a system in which scanning lines, data lines, and current supply lines are formed in a grid pattern and are driven by TFT circuits provided in each grid pattern. Since switching can be performed for each pixel, there are advantages such as gradation and memory function. For example, the circuit described in FIG. 5 of Japanese Patent Application Laid-Open No. 2004-29327, “Electrochromic Display” (published by 1991 Sangyo Tosho Co., Ltd.) ) 77-102.

[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 electrochromic display element >>
[Production of Display Element 1]
A display element 1 having the configuration shown in FIG. 1 was produced.

  FIG. 1 is a schematic cross-sectional view showing a part of the configuration of a comparative electrochromic display element using an electrolytic solution.

  In the electrochromic display element 1 shown in FIG. 1, an electrolytic solution 4 is filled in a space surrounded by a spacer 5 between the counter electrodes 2 and 3. On one counter electrode 2 (ITO electrode), a porous layer 6 (porous layer A) composed of titanium oxide adsorbed with an electrochromic dye is formed, and on the other counter electrode 3 (ITO electrode). Includes a porous layer 7 composed of tin oxide (porous layer B), and a porous white scattering layer 8 composed of titanium oxide formed on the porous layer 7. It has become.

Specifically, a titanium oxide (average primary particle size 30 nm) dispersion dispersed in terpineol is applied on an ITO electrode (electrode 2 in FIG. 1), and baked at 350 ° C. for 1 hour to be composed of titanium oxide. A porous layer A (dry film thickness 10 μm) was formed. This was immersed in a 10 mmol / L ethanol solution of Ex1 for 4 hours, Ex1 was adsorbed on the porous layer A composed of titanium oxide, and ethanol was evaporated to obtain a member 1. Next, on the other ITO electrode (electrode 3 in FIG. 1), a dispersion of tin oxide doped with antimony dispersed in terpineol (average primary particle size: 30 nm) was applied and fired at 350 ° C. for 1 hour. Titanium oxide (average primary particle size 300 nm) and polyvinyl alcohol coated with SiO ₂ on the porous layer B containing tin oxide and forming a porous layer B (dried film thickness 10 μm) composed of tin oxide A member 2 was obtained by forming a porous white scattering layer (dry film thickness 10 μm) by a blade coating method using a mixed solution of water, ethanol and water.

  Next, the member 1 and the member 2 are sandwiched with a spacer of 100 μm, and the periphery is sealed with an epoxy-based ultraviolet curable resin. Finally, a γ-butyrolactone solution containing 1 mmol / L lithium perchlorate as an electrolytic solution Was injected between the member 1 and the member 2, and the display element 1 was produced.

  In addition, the viscosity at 25 degreeC of the electrolyte solution used for preparation of the display element 1 was 1.8 mPa * s.

[Production of Display Element 2]
On the ITO electrode, a dispersion of tin oxide doped with antimony dispersed in terpineol (average primary particle size: 30 nm) is applied and fired at 350 ° C. for 1 hour to form a porous layer B composed of tin oxide (dried) Member 3 was obtained by forming a film thickness of 10 μm. Next, the member 1 used to manufacture the display element 1 and the member 3 were sandwiched with a spacer of 100 μm, and the peripheral portion was sealed with an epoxy-based ultraviolet curable resin. Finally, a γ-butyrolactone solution containing titanium dioxide coated with SiO ₂ (average primary particle size 300 nm) and 1 mmol / L lithium perchlorate is injected between the members 1 and 3 as an electrolytic solution. A display element 2 was produced.

[Production of Display Element 3]
A display element 3 having the configuration shown in FIG. 2 was produced.

  FIG. 2 is a schematic cross-sectional view showing a part of the configuration of the electrochromic display element of the present invention using a gel electrolyte.

  In FIG. 2, the configurations of the counter electrode configurations 2 and 3 and the porous layer 6 (porous layer A) and the porous layer 7 (porous layer B) are the same as those in FIG. The gel electrolyte 9 having high viscosity is applied in place of the electrolytic solution 4 except for the above.

  Specifically, a gel electrolyte layer having a thickness of 40 μm was applied on the member 3 used in the production of the display element 2 by screen printing to form a gel electrolyte layer. Next, a 40 μm spacer was placed on the gel electrolyte layer, the periphery was sealed with an epoxy-based UV curable resin, and the member 1 used for the production of the display element 1 was covered to produce the display element 3.

(Preparation of gel electrolyte 1)
In 2.5 g of γ-butyrolactone, 0.5 g of butyral resin having an average degree of polymerization of 1000 is dissolved by heating at 90 ° C. for 10 minutes, and 1.2 g of titanium dioxide coated with lithium perchlorate and SiO ₂ is mixed. The gel electrolyte 1 was obtained by dispersing for 10 minutes with a disperser. The viscosity of this gel electrolyte 1 at 25 ° C. was 750 mPa · s.

[Production of Display Element 4]
A display element 4 was produced in the same manner as in the production of the display element 3 except that the electrochromic dye Ex1 was changed to the electrochromic dye Ex2.

[Production of display elements 5 to 8]
In the production of the display element 3, display elements 5 to 8 were produced in the same manner except that the electrochromic dye Ex1 was changed to the electrochromic dyes Ex3 to Ex6, respectively.

[Production of Display Element 9]
In the production of the display element 3, a display element 9 was produced in the same manner except that the gel electrolyte 2 having the following composition was used instead of the gel electrolyte 1.

(Preparation of gel electrolyte 2)
To 2.5 g of γ-butyrolactone, 0.1 g of butyral resin having an average degree of polymerization of 1200 was dissolved by heating at 90 ° C. for 10 minutes, and further mixed with 0.2 g of titanium dioxide coated with lithium perchlorate and SiO _2. The gel electrolyte 2 was obtained by dispersing for 10 minutes with a disperser. The viscosity of this gel electrolyte 2 at 25 ° C. was 1450 mPa · s.

<< Evaluation of display element >>
[Evaluation of reflectance during white display]
A voltage of 1.5 V was applied to each of the display devices prepared above for 3 seconds to display white, and the reflectance at 550 nm was measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing. The measured reflectance and R _W, the it was used as an index of the reflectance of the white display.

[Evaluation of display speed]
A voltage of 1.5 V was applied to each of the display devices prepared above for 0.5 seconds, and the reflectance in the colored state was measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing. The minimum value of the measured reflectance was defined as R _min, and this was used as an indicator of display speed. Here, it is assumed that the display speed is higher as R _min is lower.

  The results obtained as described above are shown in Table 1.

  As is apparent from the results shown in Table 1, it can be seen that the display element 1 in which the electrolyte is liquid and has a white scattering layer has a low reflectance during white display and a low display speed.

  Further, the display element 2 in which the white scattering layer was eliminated and the titanium dioxide in the electrolyte was added was severely agglomerated of titanium dioxide and could not be evaluated.

  On the other hand, the display elements 3 to 9 of the present invention having a gel electrolyte do not cause aggregation of titanium dioxide due to the presence of the butyral resin, and even when the gap between the counter electrodes is narrow, the reflection at the time of white display is sufficient. Since the rate can be increased, it can be seen that the display speed can be increased as a result.

  Moreover, when the display element 3 of the present invention is compared with the display element 9, it can be seen that the display speed of the display element 3 using butyral resin having an average polymerization degree in the range of 300 to 1000 is higher.

  It has also been confirmed that the above effect is sufficiently effective even when an electrode of a plastic substrate is used.

It is a schematic sectional drawing which shows a part of structure of the electrochromic display element of the comparative example using electrolyte solution. It is a schematic sectional drawing which shows a part of structure of the electrochromic display element of this invention using a gel electrolyte.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrochromic display element 2, 3 Counter electrode 4 Electrolytic solution 5 Spacer 6, 7 Porous layer 8 Porous white scattering layer 9 Gel electrolyte

Claims (15)

A counter electrode; a porous layer A containing titanium oxide adsorbing at least one layer of electrochromic dye; and a porous layer B containing at least one layer of tin oxide, and the electrochromic layer between the counter electrodes An electrochromic display element comprising a gel electrolyte containing a metal oxide having an average particle size larger than that of titanium oxide on which a dye is adsorbed. 2. The electrochromic display element according to claim 1, wherein an average primary particle size of a main component of the metal oxide contained in the gel electrolyte is 200 nm or more and 1000 nm or less. The electrochromic display element according to claim 1, wherein the metal oxide contained in the gel electrolyte is titanium dioxide. The electrochromic display element according to claim 1, wherein the gel electrolyte contains a butyral resin. The electrochromic display element according to claim 4, wherein an average degree of polymerization of the butyral resin is 300 or more and 1000 or less. The electrochromic display according to any one of claims 1 to 5, wherein a mass ratio of a solvent constituting the gel electrolyte and the metal oxide is in a range of 10: 1 to 1: 1. element. The electrochromic display according to any one of claims 1 to 5, wherein a mass ratio of a solvent constituting the gel electrolyte and the metal oxide is in a range of 20: 1 to 2: 1. element. The electrochromic display element according to any one of claims 1 to 7, wherein the electrochromic dye is represented by the following general formula (1).

[Wherein, R ¹ represents — (CH ₂ ) _m — (where m represents 0 or an integer of 1 to 10), an arylene group having up to 14 carbon atoms, and a heteroarylene group, each carbon atom A branched alkylene group, an alkenylene group, or a cycloalkylene group of up to several tens, and each arylene group, heteroarylene group, branched alkylene group, branched alkenylene group, or cycloalkylene group is optionally -P (O) (OH) ₂ group - (CH _{2) n} - may have through a group. Moreover, you may substitute arbitrarily. Here, n represents 0 or an integer of 1 to 10.
R ² is a group represented by R ³ R ⁴ , wherein R ³ represents — (CH ₂ ) p— (wherein p represents 0 or an integer of 1 to 10), and R ⁴ Represents a -P (O) (OH) ₂ group, or an aryl group or heteroaryl group having up to 14 carbon atoms, a branched alkyl group, an alkenyl group, or a cycloalkyl group each having up to 10 carbon atoms.
X ⁻ represents an ion that neutralizes charge.
However, when R ² is — (CH ₂ ) ₂ —P (O) (OH) ₂ , R ¹ is not — (CH ₂ ) _m — (m is 2 or 3). In addition, when R ² is a phenyl group, R ¹ is not — (CH ₂ ) _m — (m is 2). ] The electrochromic display element according to any one of claims 1 to 7, wherein the electrochromic dye is represented by the following general formula (2).

[Wherein, R ₁ represents a substituted or unsubstituted aryl group, and R ₂ and R ₃ each represent a hydrogen atom or a substituent. X represents> N—R ₄ , an oxygen atom or a sulfur atom, and R ₄ represents a hydrogen atom or a substituent. ] The thickness of the porous layer A containing titanium oxide adsorbed with the electrochromic dye or the porous layer B containing tin oxide is 1.0 μm or more and 5.0 μm or less. Item 10. The electrochromic display element according to any one of Items 1 to 9. The electrochromic display element according to claim 1, wherein a plurality of electrochromic display elements are stacked to display a plurality of colors. The porous layer A containing titanium oxide on which different electrochromic dyes are adsorbed is arranged in a pattern between counter electrodes to display a plurality of colors. The electrochromic display element as described. The electro according to any one of claims 1 to 11, wherein a plurality of colors are displayed by adsorbing a plurality of types of electrochromic dyes to a porous layer containing the same titanium oxide on the counter electrode. Chromic display element. The electrochromic display element according to claim 1, wherein the gel electrolyte is formed by screen printing using a gel electrolyte. The electrochromic display element according to claim 1, wherein at least one counter electrode is formed on a plastic substrate.

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