JP2006227488A - Display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display element in which switching time of a screen is shortened and which has high display contrast by using a simple construction of components. <P>SOLUTION: The display element has an electrochemical transistor composed of an electrochemical active element containing an organic compound as a driving circuit, and contains an electrodeposition display element between opposing electrodes. In the display element, the electrodeposition display element has an electrolyte layer containing silver or a compound containing silver in its chemical structure, and conducts a driving operation of the opposing electrodes so as to generate dissolution and deposition of silver. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrochemical display element utilizing silver dissolution precipitation.

  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 disadvantage of the light-emitting display, 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. In addition, 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 display method that eliminates the drawbacks of each of the above-described methods, an electrodeposition (hereinafter abbreviated as ED) method that utilizes dissolution 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-mentioned patent documents in detail, the present inventor has a large problem in screen switching time in the case of simple matrix driving when the number of display pixels increases. There was found.
As a method for compensating for this, transistor driving in which a switch is provided for each pixel is known (for example, Patent Document 4). However, this disclosed technique uses a transistor utilizing a field effect, so that the device configuration is complicated, switching has no memory characteristics, consumes power, and switching is on / off, making it difficult to multi-level. .
On the other hand, although an electrochromic display element using an electrochemical transistor (for example, Patent Document 5) is also known, an organic polymer is used as a display element, and display performance such as contrast ratio and black and white color tone is sufficient. It's hard to say.
In addition, there is no mention or suggestion about the subject of the present invention and the configuration defined by the present invention.
U.S. Pat. No. 4,240,716 Japanese Patent No. 3428603 JP 2003-241227 A JP 2004-170850 A JP-T-2004-522189

  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 configuration, reduces the screen switching time, and has high display contrast.

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

(Claim 1)
A source, a drain and at least one gate comprising an electrochemically active element comprising an organic compound;
A source contact, a drain contact and at least one gate contact;
An electrochemical transistor having an electrolyte in electrical contact with the source, drain and at least one gate;
A display element including an electrodeposition type display element between the counter electrodes;
A display element, wherein at least one electrode of the counter electrode is electrically connected to at least one of the source and drain contacts of the electrochemical transistor.

(Claim 2)
The electrodeposition type display element is an electrodeposition type display element having an electrolyte layer containing silver or a compound containing silver in a chemical structure and driving the counter electrode so as to cause silver dissolution and precipitation. The display element according to claim 1, wherein the display element is provided.

(Claim 3)
The electrodeposition type display element is at least one compound represented by the following general formula (1) or (2), and at least one compound represented by the following general formula (3) or general formula (4). The display element according to claim 2, further comprising a seed.

[Wherein, L represents an oxygen atom or CH ₂ , and R _{1 to} R ₄ 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, R ₅ and R ₆ each represent a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group or an alkoxy group. ]

[Wherein R ₇ and R ₈ each represents a substituted or unsubstituted hydrocarbon group. However, when a ring containing an S atom is formed, an aromatic group is not taken. ]

[Wherein, M represents a hydrogen atom, a metal atom or quaternary ammonium. Z represents a nitrogen-containing heterocyclic ring excluding imidazole rings. n represents an integer of 0 to 5, and R ₉ represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkylcarbonamide group, an arylcarbonamide group, an alkylsulfonamide group, an arylsulfonamide group, an alkoxy group, an aryloxy group Group, alkylthio group, arylthio group, alkylcarbamoyl group, arylcarbamoyl group, carbamoyl group, alkylsulfamoyl group, arylsulfamoyl group, sulfamoyl group, cyano group, alkylsulfonyl group, arylsulfonyl group, alkoxycarbonyl group, aryl Represents an oxycarbonyl group, an alkylcarbonyl group, an arylcarbonyl group, an acyloxy group, a carboxyl group, a carbonyl group, a sulfonyl group, an amino group, a hydroxy group or a heterocyclic group, and when n is 2 or more, each R ₉ is They may be the same or different, and may be linked together to form a condensed ring. ]
(Claim 4)
The molar concentration of halogen ions or halogen atoms contained in the electrodeposition-type display element is [X] (mol / kg), and the total moles of silver contained in the electrolyte layer or silver contained in the chemical structure in the chemical structure. The display element according to claim 2, wherein when the concentration is [Ag] (mol / kg), the condition defined by the following formula (1) is satisfied.

Formula (1)
0 ≦ [X] / [Ag] ≦ 0.01
(Claim 5)
The organic compound of the electrochemically active element is at least one compound selected from polythiophene, polypyrrole, polyaniline, polyisothiaphthalene, polyphenylenevinylene, and derivatives thereof, and copolymers containing them. The display element according to claim 1.

(Claim 6)
The electrochemically active element contains 0.01% by mass or more and 4% by mass or less of inorganic particles selected from titanium oxide, aluminum oxide, zinc oxide, and silicon oxide with respect to the organic compound. Item 4. The display element according to Item 1.

  According to the present invention, it is possible to provide a display element with a simple member configuration that shortens the screen switching time and has a high display contrast.

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 uses an electrochemical transistor comprising an electrochemically active element containing an organic compound as a driving circuit, and an electrolyte containing silver or a compound containing silver in the chemical structure An electrodeposition type display element having a layer and performing a driving operation of a counter electrode so as to cause dissolution and precipitation of silver, wherein the electrolyte layer is represented by the general formula (1) or the general formula (2) A display element comprising at least one compound selected from the group consisting of at least one compound and at least one compound represented by the general formula (3) or the general formula (4). It has been found that a display element with a short switching time and a high display contrast can be realized, and the present invention has been achieved.

  Details of the display element of the present invention will be described below.

  The display element of the present invention has an electrolyte layer containing a metal or a compound containing a metal in the chemical structure between the counter electrodes, and the driving operation of the counter electrode is electrochemically performed so as to cause dissolution and precipitation of the metal. This is an electrodeposition type display element using a transistor.

  Electrodeposition type display element has advantages such as high molar spectral absorption coefficient and high precipitation reaction rate because it uses spectral absorption change of deposited metal. Electrochromic type such as conductive polymer and tungsten oxide Compared with the display element, the display element is excellent in display performance, particularly in black and white color tone and contrast. On the other hand, since a large current flows according to the precipitation reaction as much as the contrast can be increased, when active driving is performed, each switching element for each pixel is required to have a characteristic that can withstand this large current. One method for flowing a large current through the switching element is to increase the cross-sectional area of the switching portion. 1. Since the electrodeposition type display element is sandwiched between the counter electrode of the upper electrode and the lower electrode and has a white scattering layer in the display element, the lower electrode can not be seen from the display element observation side. 2. The distance between the counter electrodes of the electrodeposition type display element is usually 20 μm or more, and from the viewpoint of preventing image bleeding, the area of the lower electrode of the counter electrode can be about 1/10 of the area of the upper electrode. The space where can be placed can be increased. 3. The electrochemical transistor of the present invention has a simple structure, and the size of the switching portion can be easily changed by a simple process change. 1 above. ~ 3. For this reason, it has been found that the structure of the present invention using an electrochemical transistor as an electrodeposition type display element is an advantageous structure as compared with other structures.

(Electrochemical transistor)
FIG. 1 is a diagram in which a voltage is applied to drive an electrochemical transistor.

  FIG. 1A shows an example of a four-terminal transistor having two gate terminals and one source and one drain terminal. A Vds voltage is applied between the source 1 and the drain 2 via the source contact 5 and the drain contact 6, and the first gate contact 7 and the second gate contact 8 are connected between the first gate 3 and the second gate 4. The connection is such that the Vg voltage is applied through the connection. The polarity of the Vg voltage can be switched by the switch 10. The electrolyte 9 at least partially covers the first gate 3 and the second gate 4 and covers the source 1 and the drain 2.

  FIG. 1B shows an example of a three-terminal transistor having one terminal each for gate, source, and drain. Similar to FIG. 1A except that a Vg voltage is applied between the gate 23 and the source 1 via the gate contact 27 and the source contact 5.

The electrochemical transistor of the present invention is based on the electrochemical reaction represented by the formula (2) for transistor operation. M in the formula (2) is an electrochemically active element, and is an element including a compound whose oxidation number is changed by applying an external voltage and reversibly changing the oxidation state M ⁺ and the reduction state M ⁻ by applying an external voltage. is there. C ⁺ and A ^{− in} the formula (2) are ionic species contained in the electrolyte of the present invention, and A ⁻ forms a counter ion with M ⁺ which is the oxidation state of M to stabilize M ⁺ . .

Formula (2)
M ⁰ + C ⁺ A ⁻ ← → M ⁺ A ⁻ + C ⁺ + e ⁻
In Equation (2), the state on the left side is a state with low electrical conductivity, and the state on the right side is a state with high electrical conductivity. Switching operation can be performed by properly using this state.

  In the case of the four terminals in FIG. 1A, when the Vg voltage is applied between the first gate 3 and the second gate 4 so that the second gate 4 becomes a negative voltage, the Vds between the source 1 and the drain 2 is reduced. The electrical conductivity is low, and when the Vg voltage is applied so that the first gate 3 becomes a negative voltage, the electrolyte contact portion between the source 1 and the drain 2 changes to the state of the right side of the equation (2), and the source 1 The electrical conductivity of Vds between the drains 2 can be increased.

In the case of the three terminals in FIG. 1B, when a Vg voltage is applied between the gate 23 and the source 1 so that the source 1 is negative, the electrical conductivity of the Vds between the source 1 and the drain 2 is low. When the Vg voltage is applied so that 23 becomes negative, the electrolyte contact portion between the source 1 and the drain 2 changes to the state on the right side of the equation (2), and the electrical conductivity of the Vds between the source 1 and the drain 2 is increased. Can be increased.
In addition, a resistor can be connected to the source, drain, and gate in order to adjust electric conductivity.

  FIG. 2 is a plan view of an example in which the electrochemical transistor of the present invention and a display element are connected. That at least one electrode of the counter electrode of the display element including an electrodeposition type display element between the counter electrodes is electrically connected to at least one of the source and drain of the electrochemical transistor; It is tightening.

  FIG. 3 is a cross-sectional view of the display element of the present invention. The first counter electrode 31 in FIG. 2 and the first counter electrode 31 in FIG. 3 are the same member. Depending on whether or not the first counter electrode 31 is energized by the electrochemical transistor of the present invention, the voltage applied between the first counter electrode 31 and the second counter electrode 32 is changed to change the metal dissolution deposition state of the display element.

  FIG. 3 shows an example of one pixel. With this configuration, one pixel of the display element can be controlled independently, and since the operation can be performed in parallel with the operation of other pixels, the screen switching time of the display element can be shortened.

  In addition, the electrochemical transistor of the present invention has a switching memory property, and when erasing the screen, it is possible to apply an inversion voltage reflecting the switching state at the time of writing as it is, thereby reducing power consumption and erasing time during erasing There are advantages you can do.

  As the organic compound used for the electrochemically active element, a conductive polymer can be used. As the conductive polymer material used in the present invention, preferred compounds are listed below, but the present invention is not limited thereto. Moreover, the mixture of these compounds and anionic polymers, such as a polystyrene sulfonic acid, and the copolymer with an anionic polymer can be used as a dope compound.

  The conductive polymer referred to in the present invention refers to a polymer compound having a conductivity higher than 0.1 S / cm. Specific examples of preferable compounds as the conductive polymer material used in the present invention are listed below, but the present invention is not limited thereto.

  US Pat. Nos. 5,504,323, 5,523,555, 5,331,183, 5,454,880, 5,196,144, Each conductive polymer material described in US Pat. No. 4,145,462 can also be preferably used.

  The compounds preferably used in the present invention are polythiophene, polypyrrole, polyaniline, polyisothiaphthalene, polyphenylene vinylene, and derivatives thereof, and copolymers containing these.

  The electrochemically active element of the present invention comprises 0.01% by mass or more and 4% by mass or less of inorganic particles selected from titanium oxide, aluminum oxide, zinc oxide, and silicon oxide with respect to the organic compound. To do. The electrochemically active element can be composed of only an organic material containing the conductive polymer. However, by adding 0.01% by mass or more and 4% by mass or less of the inorganic particles, a solution-like organic substance is formed on the substrate. When applied above, there is an advantage that the viscosity of the solution can be easily adjusted and the shape uniformity of the product is increased. A preferable average primary particle size of these inorganic particles is 100 nm or less and 1 nm or more.

As a material used for the electrolyte of the electrochemical transistor of the present invention, when the electrolyte is a liquid, the following compounds can be included in the electrolyte. 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.

  Further, when the supporting electrolyte is a solid, the following compounds exhibiting 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. F-containing compounds such as chalcogenide, CaF ₂ , PbF ₂ , SrF ₂ , LaF ₃ , TlSn ₂ F ₅ , CeF ₃ , Li salts such as Li ₂ SO ₄ , Li ₄ SiO ₄ , Li ₃ PO ₄ , ZrO ₂ , CaO _{, Cd 2 O 3, HfO 2} , Y2O 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 Cl 13, Rb 3 Cu 7 Cl 10, LiN, Li 5 NI 2 Compounds such as li ₆ NBr _3, and the like.

  Moreover, a gel electrolyte can also be used as the supporting electrolyte. When the electrolyte is non-aqueous, the oil gelling agents described in paragraphs [0057] to [0059] of JP-A No. 11-185836 can be used.

  A thickener can be used for the electrolyte layer, 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 acetals) (eg, poly (vinyl formal) and poly (vinyl butyral)), poly (esters), poly (urethanes), phenoxy resins, poly (vinylidene chloride), poly ( Epoch ), 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 And polyurethane.

  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.

  Examples of materials used for the gate, source, and drain contacts include known electrode materials. Platinum, gold, silver, copper, aluminum, zinc, nickel, titanium, bismuth, and alloys thereof, oxides such as indium tin oxide, indium zinc oxide, tin oxide, indium oxide, and zinc oxide, carbon, etc. Is mentioned. Of these, silver or copper is preferred from the viewpoint of electrical conductivity and handling.

(Electrodeposition type display element)
The display element of the present invention has an electrolyte layer containing a metal or a compound containing a metal in the chemical structure between the counter electrodes, and performs an operation of driving the counter electrode so as to cause dissolution and precipitation of the metal. This is a deposition type display element. Examples of the metal compound include bismuth, copper, silver, lithium, iron, chromium, nickel, and cadmium. Silver or bismuth is preferable, and silver is most preferable.

  In the display element of the present invention, the electrolyte layer contains at least one compound represented by the general formula (1) or the general formula (2) and a compound represented by the general formula (3). Features.

  First, the compound represented by the general formula (1) according to the present invention will be described.

In the general formula (1), L represents an oxygen atom or CH ₂ , and R _{1 to} R ₄ each represents 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.

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

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

In the general formula (2), R ₅ and R ₆ 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 (2) which concerns on this invention is shown, in this invention, it is not limited only to these illustrated compounds.

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

  The compounds represented by the general formulas (1) and (2) 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.

  In the display element of this invention, it is preferable to use the compound represented by the said General formula (3) with the compound represented by the said General formula (1) or (2).

In the general formula (3), R ₇ and R ₈ 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, sulfur atoms, and halogen atoms. 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.

  Generally, in order to cause dissolution and precipitation of silver, it is necessary to solubilize silver in the electrolyte layer. For example, solubilize silver or a compound containing silver 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 structural species, halogen atoms, mercapto groups, carboxyl groups, imino groups and the like are known, but in the present invention, the thioether group is also useful as a silver solvent and has little influence on the coexisting compound, It is characterized by high solubility in solvents.

  Hereinafter, although the specific example of a compound represented by General formula (3) which concerns on this invention is shown, in this invention, it is not limited only to these illustrated compounds.

3-1: CH ₃ SCH ₂ CH ₂ OH
3-2: HOCH ₂ CH ₂ SCH ₂ CH ₂ OH
3-3: HOCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ OH
3-4: HOCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ OH
3-5: HOCH ₂ CH ₂ SCH ₂ CH ₂ OCH ₂ CH ₂ OCH ₂ CH ₂ SCH ₂ CH ₂ OH
3-6: HOCH ₂ CH ₂ OCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ OCH ₂ CH ₂ OH
3-7: H ₃ CSCH ₂ CH ₂ COOH
3-8: HOOCCH ₂ SCH ₂ COOH
3-9: HOOCCH ₂ CH ₂ SCH ₂ CH ₂ COOH
3-10: HOOCCH ₂ SCH ₂ CH ₂ SCH ₂ COOH
3-11: HOOCCH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ COOH
3-12: HOOCCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH (OH) CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ COOH
_{3-13: 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
3-14: H ₃ CSCH ₂ CH ₂ CH ₂ NH ₂
3-15: H ₂ NCH ₂ CH ₂ SCH ₂ CH ₂ NH ₂
3-16: H ₂ NCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ NH ₂
3-17: H ₃ CSCH ₂ CH ₂ CH (NH ₂ ) COOH
3-18: H ₂ NCH ₂ CH ₂ OCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ OCH ₂ CH ₂
NH ₂
3-19: H ₂ NCH ₂ CH ₂ SCH ₂ CH ₂ OCH ₂ CH ₂ OCH ₂ CH ₂ SCH ₂ CH ₂
NH ₂
3-20: H ₂ NCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂
NH ₂
3-21: HOOC (NH ₂ ) CHCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ CH (NH ₂ ) COOH
3-22: HOOC (NH ₂ ) CHCH ₂ SCH ₂ CH ₂ OCH ₂ CH ₂ OCH ₂ CH ₂ SCH ₂ CH (NH ₂ ) COOH
3-23: HOOC (NH ₂ ) CHCH ₂ OCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ OCH ₂ CH (NH ₂ ) COOH
3-24: H ₂ N (═O) CCH ₂ SCH ₂ CH ₂ OCH ₂ CH ₂ OCH ₂ CH ₂ SCH ₂ C (═O) NH ₂
3-25: H ₂ N (O =) CCH ₂ SCH ₂ CH ₂ SCH ₂ C (O =) NH _{2
3-26: H 2 NHN (O =} ) CCH 2 SCH 2 CH 2 SCH 2 C (= O) NHNH 2
3-27: H ₃ C (O =) NHCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ NHC (O =) CH ₃
3-28: H ₂ NO ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SO ₂ NH ₂
3-29: NaO ₃ SCH ₂ CH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ CH ₂ SO ₃ Na
3-30: H ₃ CSO ₂ NHCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ NHO ₂ SCH ₃
3-31: H ₂ N (NH) CSCH ₂ CH ₂ SC (NH) NH ₂ .2HBr
3-32: H ₂ (NH) CSCH ₂ CH ₂ OCH ₂ CH ₂ OCH ₂ CH ₂ SC (NH) NH ₂ .2HCl
3-33: H ₂ N (NH) CNHCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ NHC (NH) NH ₂ .2HBr
3-34: [(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 3-2 is particularly preferable from the viewpoint that the object and effects of the present invention can be exhibited.

  In the display element of the present invention, the total molar concentration of silver contained in the electrolyte layer or the compound containing silver in the chemical structure is [Ag] (mol / kg), and the above general formula (3 When the molar concentration of the thioether group of the compound represented by () is [-S-] (mol / kg), it is preferable to satisfy the condition of 2≤ [-S-] / [Ag] ≤10. When [-S-] / [Ag] is smaller than 2, there is a drawback that the solubility of silver is not sufficient and precipitates are formed at low temperatures. Moreover, when [-S-] / [Ag] is larger than 10, the solubility of silver is sufficient, but there is a drawback that the memory property is lowered. In the present invention, a more preferable range is 2.5 ≦ [−S −] / [Ag] ≦ 5.

  In the display element of the present invention, together with the compound represented by the general formula (1) or (2) according to the present invention and the compound represented by the general formula (3) according to the present invention, the general formula (4) It is preferable to contain the compound represented by these in an electrolyte layer.

  Hereinafter, the compound represented by Formula (4) will be described.

In the general formula (4), M represents a hydrogen atom, a metal atom, or quaternary ammonium. Z represents a nitrogen-containing heterocyclic ring excluding imidazole rings. n represents an integer of 0 to 5, and R ₄ represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkylcarbonamide group, an arylcarbonamide group, an alkylsulfonamide group, an arylsulfonamide group, an alkoxy group, an aryloxy group Group, alkylthio group, arylthio group, alkylcarbamoyl group, arylcarbamoyl group, carbamoyl group, alkylsulfamoyl group, arylsulfamoyl group, sulfamoyl group, cyano group, alkylsulfonyl group, arylsulfonyl group, alkoxycarbonyl group, aryl Represents an oxycarbonyl group, an alkylcarbonyl group, an arylcarbonyl group, an acyloxy group, a carboxyl group, a carbonyl group, a sulfonyl group, an amino group, a hydroxy group or a heterocyclic group, and when n is 2 or more, each R ₄ is They may be the same or different, and may be linked together to form a condensed ring.

Examples of the metal atom represented by M in the general formula (4) 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 represented by Z in the general formula (4) include 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.

Examples of the halogen atom represented by R ₄ in the general formula (4) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the alkyl group include methyl, ethyl, propyl, i- Examples include propyl, butyl, t-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, dodecyl, hydroxyethyl, methoxyethyl, trifluoromethyl, benzyl, etc. Examples of the aryl group include phenyl, naphthyl and the like. Examples of the alkylcarbonamide group include acetylamino, propionylamino, butyroylamino and the like. Examples of the arylcarbonamide group include benzoylamino and the like. Examples of the sulfonamide group include methanesulfonyl. Minosulfonyl, ethanesulfonylamino group and the like, arylsulfonamide groups include, for example, benzenesulfonylamino group, toluenesulfonylamino group and the like, and aryloxy groups include, for example, phenoxy and the like, alkylthio Examples of the group include each group such as methylthio, ethylthio, and butylthio. Examples of the arylthio group include phenylthio group and tolylthio group. Examples of the alkylcarbamoyl group include methylcarbamoyl, dimethylcarbamoyl, Examples include ethyl carbamoyl, diethyl carbamoyl, dibutyl carbamoyl, piperidyl carbamoyl, morpholyl carbamoyl and the like, and aryl carbamoyl groups include, for example, phenyl carbamoyl, methyl phenyl carbamoyl Examples include groups such as vamoyl, ethylphenylcarbamoyl, and benzylphenylcarbamoyl. Examples of the alkylsulfamoyl group include methylsulfamoyl, dimethylsulfamoyl, ethylsulfamoyl, diethylsulfamoyl, and dibutylsulfamoyl. Examples of each group include moyl, piperidylsulfamoyl, morpholylsulfamoyl, and arylsulfamoyl groups include, for example, phenylsulfamoyl, methylphenylsulfamoyl, ethylphenylsulfamoyl, benzylphenylsulfamoyl. Examples of the alkylsulfonyl group include a methanesulfonyl group and an ethanesulfonyl group. Examples of the arylsulfonyl group include phenylsulfonyl and 4-chlorophenylsulfonyl. Examples of each group include p-toluenesulfonyl and the like. Examples of the alkoxycarbonyl group include groups such as methoxycarbonyl, ethoxycarbonyl and butoxycarbonyl. Examples of the aryloxycarbonyl group include phenoxycarbonyl and the like. Examples of the alkylcarbonyl group include acetyl, propionyl, butyroyl, and the like. Examples of the arylcarbonyl group include a benzoyl group and an alkylbenzoyl group. Examples of the acyloxy group include acetyloxy. , Propionyloxy, butyroyloxy and the like, and examples of the heterocyclic group include oxazole ring, thiazole ring, triazole ring, selenazole ring, tetrazole ring, oxadiazole ring, thiadiazole ring, thiazol ring, and the like. Down ring, a triazine ring, a benzoxazole ring, benzothiazole ring, an indolenine ring, benzimidazole benzoselenazole ring, naphthothiazole ring, triazaindolizine ring, diaza indolizine ring, tetraazacyclododecane indolizine ring group, and the like. These substituents further include those having a substituent.

  Next, although the preferable specific example of a compound represented by General formula (4) is shown, this invention is not limited to these compounds.

  Among the above-exemplified compounds, Exemplified Compounds 4-12 and 4-18 are particularly preferable from the viewpoint that the object and effects of the present invention can be exhibited.

  In the display element of the present invention, the total molar concentration of silver contained in the electrolyte layer or the compound containing silver in the chemical structure is [Ag] (mol / kg), and the general formula ( When the molar concentration of the mercapto group of the compound represented by 4) is [SM] (mol / kg), it is preferable that the condition of 0 <[− SM] / [Ag] ≦ 0.1 is satisfied. When the compound represented by the general formula (4) according to the present invention is not used, the light stability of the electrolyte layer is not sufficient, resulting in long-time irradiation with external light and brown stains under a high temperature environment. The white display is deteriorated, the silver reduction reaction proceeds further with blackened silver as a nucleus, and the reflectance is further lowered than in the initial state. On the other hand, when [-SM] / [Ag] exceeds 0.1, the memory property is lowered by the action of dissolving the blackened silver of the mercapto compound. More preferably, 0 <[− SH] / [Ag] ≦ 0.02.

  In the display element of the present invention, the molar concentration of halogen ions or halogen atoms contained in the electrolyte layer is [X] (mol / kg), and silver or silver contained in the electrolyte layer is contained in the chemical structure. When the total molar concentration of silver is [Ag] (mol / kg), it is preferable to have a condition of 0 ≦ [X] / [Ag] ≦ 0.01.

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] / [Ag] is larger than 0.1, X− → X ₂ is generated during the redox reaction of silver, and X ₂ easily cross-oxidizes with blackened silver to dissolve the blackened silver. Therefore, the molar concentration of halogen atoms is preferably as low as possible relative to the molar concentration of silver. In the present invention, 0 ≦ [X] / [Ag] ≦ 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.

(Electrolytes)
The electrolyte of the display element of the present invention includes silver iodide, silver chloride, silver bromide, silver oxide, silver sulfide, silver citrate, silver acetate, silver behenate, silver p-toluenesulfonate, silver with mercapto Known silver salt compounds such as salts and silver complexes with iminodiacetic acids 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 silver ion concentration contained in the electrolyte layer according to the present invention is preferably 0.2 mol / kg ≦ [Ag] ≦ 2.0 mol / kg. If the silver ion concentration is less than 0.2 mol / kg, it becomes a dilute silver solution, and the driving speed is delayed. If it is greater than 2 mol / kg, the solubility deteriorates, and precipitation tends to occur during low-temperature storage, which is disadvantageous. It is.

  As the other electrolyte material, the same type as the electrolyte of the electrochemical transistor described above can be used.

(White particles with added electrolyte)
In the display element of the present invention, the electrolyte layer preferably includes white particles.

  Examples of the white particles according to 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, and phosphoric acid. Magnesium hydrogen, alkaline earth metal salt, talc, kaolin, zeolite, acid clay, glass, organic compounds such as polyethylene, polystyrene, acrylic resin, ionomer, ethylene-vinyl acetate copolymer resin, benzoguanamine resin, urea-formalin resin, melamine Formalin resin, polyamide resin, or the like may be used alone or in combination, or in a state having voids that change the refractive index in the particles.

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

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

(Thickener added with electrolyte)
In the display element of the present invention, the same thickener as described in the above-mentioned electrochemical transistor can be used for the electrolyte layer.

(Other additives for electrolyte layer)
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 agent, hardener, surfactant, thickener, plasticizer, slip agent, UV absorber, irradiation prevention dye, filter light absorption dye, anti-bacterial agent, polymer latex, heavy metal, antistatic agent, matting agent Etc. can be contained as required.

  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
(Layer structure)
The constituent layers between the counter electrodes of the display element of the present invention will be further described.

As a constituent layer according to the display element of the present invention, a constituent layer containing a hole transport material can be provided. Examples of hole transport materials include aromatic amines, triphenylene derivatives, oligothiophene compounds, polypyrroles, polyacetylene derivatives, polyphenylene vinylene derivatives, polythienylene vinylene derivatives, polythiophene derivatives, polyaniline derivatives, polytoluidine derivatives, CuI, CuSCN CuInSe ₂ , Cu (In, Ga) Se, CuGaSe ₂ , Cu ₂ O, CuS, CuGaS ₂ , CuInS ₂ , CuAlSe ₂ , GaP, NiO, CoO, FeO, Bi ₂ O ₃ , MoO ₂ , Cr ₂ O ₃ Etc.

(substrate)
Examples of the substrate that can be used in the present invention include polyolefins such as polyethylene and polypropylene, polycarbonates, cellulose acetate, polyethylene terephthalate, polyethylene dinaphthalene dicarboxylate, polyethylene naphthalates, polyvinyl chloride, polyimide, and polyvinyl acetal. Synthetic plastic films such as polystyrene can also be preferably used. Syndiotactic polystyrenes are also preferred. These can be obtained, for example, by the methods described in JP-A Nos. 62-117708, 1-46912 and 1-178505. Further, a metal substrate such as stainless steel, a paper support such as baryta paper and resin coated paper, and a support provided with a reflective layer on the plastic film, supported by JP-A-62-253195 (pages 29-31) The thing described as a body is mentioned. RDNo. 17643, page 28, ibid. No. 18716, page 647, right column to page 648, left column, and No. 307105, page 879 can also be preferably used. As these supports, those having resistance to curling due to heat treatment of Tg or less as in US Pat. No. 4,141,735 can be used. Further, the surface of these supports may be subjected to surface treatment for the purpose of improving the adhesion between the support and other constituent layers. In the present invention, glow discharge treatment, ultraviolet irradiation treatment, corona treatment, and flame treatment can be used as the surface treatment. Furthermore, the support body described in pages 44 to 149 of publicly known technology No. 5 (issued by Aztec Co., Ltd. on March 22, 1991) can also be used. Furthermore, RDNo. 308119, page 1009, Product Licensing Index, Volume 92, P108, “Supports”, and the like. In addition, a glass substrate or an epoxy resin kneaded with glass can be used.

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

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

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

  Sealing agent is for sealing so as not to leak outside, and is also called sealing agent, epoxy resin, urethane resin, acrylic resin, vinyl acetate resin, enthiol resin, silicone resin, modified polymer resin A curing type such as a thermosetting type, a photocuring type, a moisture curing type, an anaerobic curing type, etc. 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.

(Display element driving method)
In the display element of the present invention, it is preferable to perform a driving operation in which silver black is precipitated by applying a voltage equal to or higher than the precipitation overvoltage, and silver black is continuously precipitated by applying a voltage lower than the precipitation overvoltage. By performing this driving operation, the writing energy can be reduced, the driving circuit load can be reduced, and the writing speed as a screen can be improved. It is generally known that overvoltage exists in electrode reactions in the electrochemical field. For example, overvoltage is described in detail on page 121 of “Introduction to Chemistry of Electron Transfer—Introduction to Electrochemistry” (published by Asakura Shoten in 1996). Since the display element of the present invention can also be regarded as an electrode reaction between the electrode and silver in the electrolyte, it can be easily understood that overvoltage exists even in silver dissolution precipitation. Since the magnitude of the overvoltage is governed by the exchange current density, it is possible to continue silver black precipitation by applying a voltage equal to or lower than the precipitation overvoltage after the formation of silver black as in the present invention. However, it is estimated that electron injection can be easily performed with little extra electric energy.

(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, health insurance cards, Basic Resident Registers, passports, electronic books, etc.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to this.

Example 1
<< Production of electrochemical transistor >>
Screen-printed poly (3,4-ethylenedioxythiophene) on poly (3,4-ethylenedioxythiophene), a conductive polymer aqueous solution doped with polystyrene sulfonic acid (solid content 1%), with a dry thickness of 0.2 μm and the pattern shown in FIG. And dried at 60 ° C. for 1 hour.

  Next, using silver paste ink, a source contact, a drain contact, a gate contact, and a first counter electrode were formed. Next, an aqueous solution of polystyrene sulfonic acid (33% by mass), glycerol (8% by mass) and D-sorbitol (8% by mass) was applied to the position shown in FIG. Dried.

<< Production of display element >>
[Production of display element 1]
(Preparation of electrolyte solution 1)
After adding 90 mg of sodium iodide and 75 mg of silver iodide in 2.5 g of dimethyl sulfoxide and completely dissolving it, 0.5 g of titanium oxide (primary average particle size 30 nm) is added and titanium oxide is added using an ultrasonic disperser. Was dispersed. 150 mg of polyvinyl alcohol (polymerization degree 4500, saponification degree 87-89%) was added to this solution, and it stirred for 1 hour, heating at 120 degreeC, and the electrolyte solution 1 was obtained.

(Preparation of display element 1)
A solution obtained by adding polyacrylic spherical beads having an average particle diameter of 50 μm to the electrolyte solution 1 so as to have a volume fraction of 10% is applied onto the first counter electrode, and the ITO electrode is sandwiched between them. Thus, pressing was performed at a pressure of 9.8 kPa, and the peripheral portion was sealed with an olefin-based sealant to produce a display element.

(Drive, evaluation)
A voltage (Vg) of 0 V, 0.3 V, 0.6 V, and 0.9 V was applied for 20 seconds between the gate contact and the source contact. Thereafter, a voltage of 1.5 V was applied between the source contact and the second counter electrode for 200 msec, and the reflectance at 550 nm from the upper surface of the ITO electrode was measured with a Minolta spectrocolorimeter CM-3700d. The obtained results are shown in Table 1.

  As is apparent from Table 1, it was found that the display device of the present invention can change the reflectance of the display element by switching control of the electrochemical transistor.

  From the state of Table 1, when a voltage of −1.5 V was applied between the source contact and the second counter electrode for 400 msec, the reflectivity returned to 64% and it was found that there was a switching memory property.

  Next, from this state, 0, -0.3, -0.6, and -0.9 V are applied between the gate contact and the source contact, respectively, and a voltage of 1.5 V is applied between the source contact and the second counter electrode for 200 milliseconds. When applied, the reflectivity was 64%, and it was found that the switch returned to the initial state.

Example 2
Evaluation was performed in the same manner as in Example 1 except that the electrolyte solution 1 of the display element 1 of Example 1 was changed to the electrolyte solution 2. The obtained results are shown in Table 2. As is apparent from Table 2, it was found that the display device 2 can change the reflectance of the display element by switching control of the electrochemical transistor, and a display element with higher contrast than that of Example 1 can be obtained.

(Preparation of electrolyte solution 2)
In 2.5 g of propylene carbonate / ethylene carbonate (mass ratio 7/3), 100 mg of silver p-toluenesulfonate, 150 mg of 3,6-dithia-1,8-octanediol and 1 mg of mercaptotriazole were added and completely dissolved. Thereafter, 0.5 g of titanium oxide (primary average particle size 30 nm) was added, and the titanium oxide was dispersed with an ultrasonic disperser.

  150 mg of polyvinyl alcohol (polymerization degree 4500, saponification degree 87-89%) was added to this solution, and it stirred for 1 hour, heating at 120 degreeC, and the electrolyte solution 2 was obtained.

Example 3
Except for the contents described below, display elements 3 to 8 were produced in the same manner as in Example 1 or 2, and the same evaluation was performed.

  In the display element 3, silicon dioxide (average primary particle size 30 nm) was added to the conductive polymer aqueous solution of the display element 1 in a solid content of 0.2%.

  In the display element 4, the sodium iodide of the display element 1 was changed to lithium bromide and the silver iodide was changed to bismuth chloride.

  For the display element 5, the propylene carbonate / ethylene carbonate of the display element 2 was changed to dimethylformamide.

  In the display element 6, the 3,6-dithia-1,8-octanediol of the display element 5 was removed, and mercaptoimidazole was changed to 300 mg.

  For the display element 7, the mercaptotriazole of the display element 5 was excluded.

  In the display element 8, the silver p-toluenesulfonate of the display element 2 was changed to silver bromide.

  The evaluation results are shown in Table 3. As apparent from Table 3, it was found that the display elements 3 to 8 can change the reflectance of the display element by switching control of the electrochemical transistor, and the display elements satisfying the requirements of the present invention have high contrast.

It is a schematic block diagram which shows the fundamental structure of the electrochemical transistor which is a drive circuit of the display element of this invention. It is a schematic block diagram which shows the basic composition which connected the electrochemical transistor and display element of this invention. Sectional view of display element of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Source 2 Drain 3 1st gate 4 2nd gate 5 Source contact 6 Drain contact 7 1st gate contact 8 2nd gate contact 9 Electrolyte 10 Switch 23 Gate 27 Gate contact 31 1st counter electrode 32 2nd counter electrode

Claims (6)

A source, a drain and at least one gate comprising an electrochemically active element comprising an organic compound;
A source contact, a drain contact and at least one gate contact;
An electrochemical transistor having an electrolyte in electrical contact with the source, drain and at least one gate;
A display element including an electrodeposition type display element between the counter electrodes;
A display element, wherein at least one electrode of the counter electrode is electrically connected to at least one of the source and drain contacts of the electrochemical transistor. The electrodeposition type display element is an electrodeposition type display element having an electrolyte layer containing silver or a compound containing silver in a chemical structure and driving the counter electrode so as to cause silver dissolution and precipitation. The display element according to claim 1, wherein the display element is provided. The electrodeposition type display element is at least one compound represented by the following general formula (1) or (2), and at least one compound represented by the following general formula (3) or general formula (4). The display element according to claim 2, further comprising a seed.

[Wherein, L represents an oxygen atom or CH ₂ , and R _{1 to} R ₄ 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, R ₅ and R ₆ each represent a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group or an alkoxy group. ]

[Wherein R ₇ and R ₈ each represents a substituted or unsubstituted hydrocarbon group. However, when a ring containing an S atom is formed, an aromatic group is not taken. ]

[Wherein, M represents a hydrogen atom, a metal atom or quaternary ammonium. Z represents a nitrogen-containing heterocyclic ring excluding imidazole rings. n represents an integer of 0 to 5, and R ₉ represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkylcarbonamide group, an arylcarbonamide group, an alkylsulfonamide group, an arylsulfonamide group, an alkoxy group, an aryloxy group Group, alkylthio group, arylthio group, alkylcarbamoyl group, arylcarbamoyl group, carbamoyl group, alkylsulfamoyl group, arylsulfamoyl group, sulfamoyl group, cyano group, alkylsulfonyl group, arylsulfonyl group, alkoxycarbonyl group, aryl Represents an oxycarbonyl group, an alkylcarbonyl group, an arylcarbonyl group, an acyloxy group, a carboxyl group, a carbonyl group, a sulfonyl group, an amino group, a hydroxy group or a heterocyclic group, and when n is 2 or more, each R ₉ is They may be the same or different, and may be linked together to form a condensed ring. ] The molar concentration of halogen ions or halogen atoms contained in the electrodeposition-type display element is [X] (mol / kg), and the total moles of silver contained in the electrolyte layer or silver contained in the chemical structure in the chemical structure. The display element according to claim 2, wherein when the concentration is [Ag] (mol / kg), the condition defined by the following formula (1) is satisfied.
Formula (1)
0 ≦ [X] / [Ag] ≦ 0.01 The organic compound of the electrochemically active element is at least one compound selected from polythiophene, polypyrrole, polyaniline, polyisothiaphthalene, polyphenylenevinylene, and derivatives thereof, and copolymers containing them. The display element according to claim 1. The electrochemically active element contains 0.01% by mass or more and 4% by mass or less of inorganic particles selected from titanium oxide, aluminum oxide, zinc oxide, and silicon oxide with respect to the organic compound. Item 4. The display element according to Item 1.

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