JP2008026454A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device of an ED system which has simple member constitution, can be driven with a low voltage, and has a high display contrast and high white display reflectivity and exhibits improved density unevenness resistance characteristics when repetitively driven. <P>SOLUTION: The electrochemical display device has between counter electrodes, an electrolyte containing silver or a compound including silver in a chemical structure and performs image display by generating a potential difference between the counter electrodes to give rise to dissolution and deposition of the silver. The display device has a porous conductive material layer internally provided with a porous array substantially exhibiting two-dimensional periodicity on the one counter electrode. <P>COPYRIGHT: (C)2008,JPO&INPIT

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 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. 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 (for example, yellow, magenta, cyan, blue, green, red, etc.) is not sufficient, and the memory There is a concern that a complicated film configuration such as a vapor deposition film is necessary for the display cell in order to ensure the property.

  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 or precipitation of a metal or a 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 the inventor's detailed examination of the techniques disclosed in each of the above-mentioned documents, in the conventional technique, when repeated driving is performed, density unevenness of the entire image occurs, and in particular, white display during whitening causes stains. It turns out that there is a problem of being recognized.
U.S. Pat. No. 4,240,716 Japanese Patent No. 3428603 JP 2003-241227 A

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its object is to provide a simple member configuration, an ED display element that can be driven at a low voltage, has high display contrast, and high white display reflectance, and is repeatedly driven. An object of the present invention is to provide a display device with improved density unevenness resistance.

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

  1. Electrochemical display that has an electrolyte containing silver or a compound containing silver in the chemical structure between the counter electrodes, and generates an electric potential difference between the counter electrodes to cause dissolution and precipitation of silver. A display element, comprising a porous conductive material layer having a porous array substantially having a two-dimensional periodicity on one counter electrode.

  2. Electrochemical display that has an electrolyte containing silver or a compound containing silver in the chemical structure between the counter electrodes, and generates an electric potential difference between the counter electrodes to cause dissolution and precipitation of silver. A display element, comprising a porous conductive material layer having a porous array substantially having a three-dimensional periodicity on one counter electrode.

  3. 3. The display element according to item 1 or 2, wherein the counter electrode on which the porous conductive material layer is formed is a transparent electrode.

  4). 4. The display element as described in 3 above, wherein the conductive material constituting the porous conductive material layer is substantially the same compound as the transparent electrode.

  5. 5. The display element according to any one of 1 to 4, wherein the holes constituting the porous array in the porous conductive material layer are substantially spherical.

  6). 6. The display element as described in 5 above, wherein the diameter of the holes constituting the porous arrangement in the porous conductive material layer is 1.0 μm or less.

  7). 7. The display element as described in 6 above, wherein the diameter of the holes constituting the porous array in the porous conductive material layer is 500 nm or less.

  8). Any one of 1 to 7 above, wherein the conductive material forming the porous conductive material layer is substantially the same material as the counter electrode on which the porous conductive material layer is formed. The display element according to item.

  9. 9. The display element according to any one of 1 to 8 above, wherein the electrolyte is substantially liquid, and the pores of the porous conductive material layer are filled with an electrolyte solution.

  10. The electrolyte contains 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 (4). 10. The display element according to any one of 1 to 9 above.

[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. ]
General formula (3)
R ₇ -S-R ₈
[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. 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. ]
11. The porous conductive material layer forms a periodic film of colloidal crystal particles on the electrode side of a substrate having an electrode on the surface, and is applied with a liquid containing a conductive material layer forming substance. 11. The display element as described in any one of 1 to 10 above, which is formed by removing colloidal crystal particles by a baking treatment.

  12 Any one of 1 to 11 above, wherein a porous white scattering layer is provided between the porous conductive material layer and the other counter electrode not in contact with the porous conductive material layer. The display element according to claim 1.

  According to the present invention, there is provided an ED display element that has a simple member configuration, can be driven at a low voltage, has high display contrast, and high white display reflectance, and has improved density unevenness resistance during repeated driving. I was able to.

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

  As a result of intensive studies in view of the above problems, the present inventor 1) has an electrolyte containing silver or a compound containing silver in the chemical structure between the counter electrodes, and generates a potential difference between the counter electrodes. This is an electrochemical display element that displays an image by causing dissolution and precipitation of silver, and has a porous conductive structure having a porous array having substantially a two-dimensional periodicity on one counter electrode. A display element characterized by having a conductive material layer, or 2) having an electrolyte containing silver or a compound containing silver in a chemical structure between counter electrodes, and generating a potential difference between the counter electrodes An electrochemical display element that displays an image by causing dissolution and precipitation of silver, and a porous conductive material having a porous array having a substantially three-dimensional periodicity on one counter electrode With a display element characterized by having a layer, It has been found that an ED type display element that can be driven at a low voltage, has a high display contrast, and a high white display reflectance, and can realize a display element with improved density unevenness resistance during repeated driving. It is up to.

  Details of the present invention will be described below.

  The display element of the present invention is characterized by having a porous conductive material layer provided with a porous array having substantially a two-dimensional periodicity on one of the counter electrodes.

  The porous array showing the two-dimensional periodicity in the present invention is a structure in which a large number of holes are two-dimensionally repeated.

  In addition, the display element of the present invention is characterized by having a porous conductive material layer having a porous array substantially having a three-dimensional periodicity on one of the counter electrodes.

  A case where a two-dimensional structure of an array in which a large number of holes are two-dimensionally repeated is three-dimensionally periodically arranged in a stacked state is called a porous array exhibiting three-dimensional periodicity.

  Conventionally, as a method for forming a porous conductive layer, for example, as described in JP-A-2006-73321, a liquid mixture of an organic solvent containing indium, tin and alcohol and a surfactant is applied onto a substrate. However, although a method for forming a porous film by heat-treating this substrate is disclosed, since this method uses the generation of random bubbles by a surfactant, The distribution has no periodicity. Such a porous layer having no periodicity does not lead to improvement in image density unevenness which is a problem of the present invention.

  In addition to the periodicity of the hole arrangement as described above, the homogeneity of the holes is also important. The holes for exhibiting three-dimensional periodicity are preferably three-dimensionally homogeneous, that is, substantially spherical. The term “substantial” as used in the present invention means that deformation due to its own weight or the like can be tolerated to some extent, and if the fluctuation is approximately ± 10%, there is no practical problem.

  The diameter of the spherical hole is preferably 10 nm or more and 1.0 μm or less, more preferably 10 nm or more, from the penetration of the electrolyte solution, the dissolution / deposition reaction rate of the silver image, the strength of the porous conductive material layer, and the like. 500 nm or less.

  The display element of the present invention is characterized in that since a silver image is deposited on the transparent electrode on the viewing side, the porous conductive material layer is provided on the transparent electrode.

  The conductive material forming the porous conductive material layer of the present invention is preferably formed of the same compound as the transparent electrode, and more preferably substantially transparent when the layer is formed. As such a conductive material, for example, tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), or aluminum-doped zinc oxide (AZO) is suitable.

  In order to form a porous conductive material layer having two-dimensional periodicity or three-dimensional periodicity defined in the present invention, a two-dimensional periodic film of colloidal crystal latex particles is formed on the electrode side of a substrate having electrodes on the surface. A so-called colloidal crystal template method is preferable, in which a liquid containing a conductive material forming substance is formed, and the colloidal crystal particles are extinguished by baking or dissolution. Colloidal crystals have a homogeneous structure usually formed from small particles suspended in solution. It is formed by slowly precipitating particles of fairly uniform size in a liquid.

  Preferred colloidal crystal materials include, but are not limited to, polystyrene, polymethyl methacrylate, silica and the like. An organic compound such as polystyrene is particularly preferable because it can be easily removed by heating.

  Formation of a two-dimensional periodic array using a colloidal crystal can be easily formed by a substrate pulling method using a dispersion of colloidal crystals. Further, by adjusting the viscosity of the colloidal crystal dispersion liquid, it is possible to apply by a method such as a blade coating method or a spin coating method. By repeating the formation of such a two-dimensional periodic array a plurality of times, a porous conductive material layer having a three-dimensional periodicity can be formed.

  When forming a porous conductive material layer having such periodicity, the amount of thickener used for viscosity adjustment should be in a range that does not affect the two-dimensional periodic formation of colloidal crystals. is there.

  In addition, the porous conductive material layer having three-dimensional periodicity is formed in one step by controlling the coating film thickness by using a blade coating method, an inkjet method, a printing method, or the like by appropriately adjusting the viscosity. It is also possible.

  In addition, as a method of forming an array having periodicity in three dimensions, literatures, A.I. van Bladeren et al. , “Template-directed colloidal crystallisation”, Nature, Vol. 358321 (Jan. 1997), a colloidal epitaxy method is known.

  Hereinafter, the main structure of the display element of the present invention and a method for forming a porous conductive material layer having periodicity according to the present invention will be described with reference to the drawings. Note that the present invention is not limited only to the configuration illustrated in the drawing.

  FIG. 1 is a schematic cross-sectional view illustrating an example of an ED display portion of a display element having a porous conductive material layer having a porous array exhibiting two-dimensional periodicity.

  In FIG. 1, the ED display unit is provided with a pair of counter electrodes arranged at opposing positions. A transparent electrode such as an ITO electrode is provided on the electrode 2 which is one of the counter electrodes close to the ED display portion, and a metal electrode such as a silver electrode is provided on the other electrode 1. An electrolyte 3 having silver or a compound containing silver in the chemical structure is supported between the electrode 1 and the electrode 2, and by applying positive and negative voltages between the counter electrodes, the electrode 1 and the electrode 2 are supported. A silver oxidation-reduction reaction is performed above, and the black state of the reduced silver image and the state of transparent silver ions in the oxidized state can be switched reversibly.

  In the display element of the present invention, among the pair of counter electrodes, a porous white layer in which metal oxide particles are laminated on the electrode 1 on the non-display portion side for the purpose of increasing display contrast and reflectance during white display. A scattering layer 6 is provided.

  In the display element of the present invention, the porous conductive material layer 8 having a porous array showing two-dimensional periodicity is provided on the electrode 2 on the display portion side of the pair of counter electrodes.

  As a method for forming a porous conductive material layer 8 having a porous array exhibiting two-dimensional periodicity according to the present invention, as shown in FIG. 1a, colloidal crystal latex particles 4 (for example, A two-dimensional periodic film 5 of polystyrene, methyl methacrylate or the like) is formed according to a known coating film forming method.

  Next, as shown in FIG. 1 b, a liquid 7 containing a conductive material (for example, ITO, FTO, etc.) is applied to the formed two-dimensional periodic film 5. Thereafter, as shown in FIG. 1 c), the colloidal crystal latex particles 4 are extinguished by a sintering process or the like to form a porous conductive material layer 8 having a porous array showing two-dimensional periodicity.

  FIG. 2 is a schematic cross-sectional view showing an example of an ED display portion of a display element having a porous conductive material layer having a porous array exhibiting three-dimensional periodicity.

  The basic configuration of the display device of FIG. 2 is the same as that of FIG. 1, except that colloidal crystal latex particles 4 (for example, polystyrene, methyl methacrylate, etc.) are formed on the electrode 2 as shown in FIG. A plurality of two-dimensional periodic films 5 are laminated to form a three-dimensional periodic film 9 made of colloidal crystal latex particles 4 exhibiting three-dimensional periodicity, and then, as shown in FIG. A liquid 7 containing a conductive material (for example, ITO, FTO, etc.) is applied to the periodic film 9. Thereafter, as shown in FIG. 2 c), the colloidal crystal latex particles 4 are eliminated by a sintering process or the like, and a porous conductive material layer 10 having a porous array exhibiting three-dimensional periodicity is formed.

  In the display element of the present invention, it is preferable that the pores of these porous conductive material layers are sufficiently filled with the electrolyte solution.

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

[Electrolyte material]
In the display element of the present invention, the electrolyte may 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.

[Silver or silver compound]
The silver or silver compound according to the present invention is silver or a compound containing silver in the chemical structure, such as silver oxide, silver sulfide, metallic silver, silver colloidal particles, silver halide, silver complex compound, silver ion, etc. It is a general term for compounds, and there are no particular limitations on the state species of the phase such as the solid state, the solubilized state in liquid and the gas state, and the charged state species such as neutral, anionic and cationic.

  The silver ion concentration contained in the electrolyte 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.

(Electrolyte additive)
In the display element of the present invention, the electrolyte is composed of at least one compound represented by the following general formula (1) or (2) and a compound represented by the following general formula (3) or general formula (4). It is preferable to contain at least one kind.

In the general formula (1), L represents an oxygen atom or CH ₂ , and R _{1 to} R ₄ each represent a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group, or an alkoxy group.

In the general formula (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.

General formula (3)
R ₇ -S-R ₈
In the general formula (3), R ₇ and R ₈ each represent a substituted or unsubstituted hydrocarbon group. However, when a ring containing an S atom is formed, an aromatic group is not taken.

In the general formula (4), M represents a hydrogen atom, a metal atom or quaternary ammonium. Z represents a nitrogen-containing heterocyclic ring. n represents an integer of 0 to 5, and R ₉ represents 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, an alkylthio group. Group, arylthio group, alkylcarbamoyl group, arylcarbamoyl group, carbamoyl group, alkylsulfamoyl group, arylsulfamoyl group, sulfamoyl group, cyano group, alkylsulfonyl group, arylsulfonyl group, alkoxycarbonyl group, aryloxycarbonyl group Represents 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 the same. They may be different from each other or may be linked to each other to form a condensed ring.

  First, the compound represented by the general formula (1) 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.

  Hereinafter, although the specific example of a compound represented by General formula (1) is shown, in this invention, it is not limited only to these illustrated compounds.

  Next, the compound represented by the general formula (2) 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) 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) are one kind of electrolyte solvents. However, in the display element of the present invention, another solvent is used in combination as long as the object effects of the present invention are not impaired. be able to. 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 the present invention, it is preferable to use the compound represented by the general formula (3) or (4) together with the compound represented by the general formula (1) or (2).

  In the general formula (3), R7 and R8 each represent a substituted or unsubstituted hydrocarbon group, and these include a linear 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 an electrolyte. 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) 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 N (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.

  Next, 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. 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.

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 ₉ 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.

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

Formula (1)
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 0.01, X ⁻ → X ₂ is generated during the redox reaction of silver, and X ₂ easily cross-oxidizes with blackened silver to dissolve 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.

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

  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
(Porous white scattering layer)
In the present invention, from the viewpoint of further increasing the display contrast and white display reflectance, a porous white scattering layer may be provided as shown in FIGS.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

〔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.

[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. The display element of the present invention is obtained by injecting the electrolyte composition into the display cell by a vacuum injection method or the like.

[Driving method of display element]
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 excess electric energy.

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

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

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

<< Production of each component material >>
[Production of electrodes]
(Production of electrode 1)
An ITO film having a pitch of 145 μm and an electrode width of 130 μm was formed on a glass substrate having a thickness of 1.5 mm and a size of 2 cm × 4 cm to obtain a transparent electrode (electrode 1).

(Preparation of electrode 2)
An FTO film having a pitch of 145 μm and an electrode width of 130 μm was formed on a glass substrate having a thickness of 1.5 mm and a size of 2 cm × 4 cm to obtain a transparent electrode (electrode 2).

(Preparation of electrode 3)
A silver-palladium electrode (electrode 3) having an electrode thickness of 0.8 μm, a pitch of 145 μm, and an electrode interval of 130 μm is formed on a glass substrate having a thickness of 1.5 mm and a size of 2 cm × 4 cm by using a known method. Got.

[Formation of porous conductive material layer]
(Formation of porous conductive material layer 1)
A coating solution was prepared by adding 10% by mass of polyoxyethylene / polyoxypropylene glycol as a nonionic surfactant to the ITO slurry. Next, the coating solution is spin-coated on the electrode 1 under a condition of 500 rotations / minute, and after a drying treatment at 150 ° C. for 5 minutes, a baking treatment is performed in the atmosphere at 500 ° C. for 60 minutes. A conductive material layer 1 was formed.

(Formation of porous conductive material layer 2)
A single layer film of latex particles was formed on the electrode 1 by a substrate pulling method using an aqueous dispersion of polystyrene latex particles having an average particle diameter of 48 nm. After applying ITO slurry to this and performing a drying process at 150 ° C. for 5 minutes, a baking process is performed in the atmosphere at 500 ° C. for 60 minutes to remove latex particles, and the ITO porous conductive material layer 2 Formed.

(Formation of porous conductive material layer 3)
A three-dimensional array film of latex particles was formed on the electrode 2 by screen printing using an aqueous dispersion of polystyrene latex particles having an average particle diameter of 76 nm. The FTO solution was spray-coated thereon to completely coat the latex particles, and this was subjected to a baking treatment at 500 ° C. for 60 minutes to remove the polystyrene latex particles, thereby forming a porous conductive material layer 3 of FTO. .

(Formation of porous conductive material layer 4)
A three-dimensional array film of latex particles was formed on the electrode 1 by screen printing using an aqueous dispersion of polystyrene latex particles having an average particle diameter of 200 nm. After applying ITO slurry to this and performing a drying process at 150 ° C. for 5 minutes, a baking process is performed in the atmosphere at 500 ° C. for 60 minutes to remove latex particles, and the ITO porous conductive material layer 4 Formed.

(Formation of porous conductive material layer 5)
A single layer film of latex particles was formed on the electrode 1 by a substrate pulling method using an aqueous dispersion of polystyrene latex particles having an average particle diameter of 475 nm. This was sprayed with FTO solution to completely coat the latex particles. This was subjected to a baking treatment at 500 ° C. for 60 minutes to remove polystyrene latex particles, thereby forming a porous conductive material layer 4 of FTO.

(Formation of porous conductive material layer 6)
A single layer film of latex particles was formed on the electrode 1 by a substrate pulling method using an aqueous dispersion of polystyrene latex particles having an average particle diameter of 600 nm. After applying ITO slurry to this and performing a drying process at 150 ° C. for 5 minutes, a baking process is performed in the atmosphere at 500 ° C. for 60 minutes to remove latex particles, and the ITO porous conductive material layer 6 Formed.

(Formation of porous conductive material layer 7)
A three-dimensional array film of latex particles was formed on the electrode 1 by a blade coating method using an aqueous dispersion of polystyrene latex particles having an average particle diameter of 20 nm. After applying ITO slurry to this and performing a drying process at 150 ° C. for 5 minutes, a baking process is performed in the atmosphere at 500 ° C. for 60 minutes to remove latex particles, and the ITO porous conductive material layer 7 Formed.

(Preparation of electrolyte)
(Preparation of electrolyte solution 1)
In 2.5 g of dimethyl sulfoxide, 90 mg of sodium iodide and 75 mg of silver iodide were added and completely dissolved, and then 150 mg of polyvinylpyrrolidone (average molecular weight 15000) was added and stirred for 1 hour while heating to 120 ° C. Liquid 1 was obtained.

(Adjustment of electrolyte 2)
In 2.5 g of propylene carbonate, 100 mg of silver p-toluenesulfonate and Exemplified Compound 4-12 were added and completely dissolved, and then 150 mg of polyethylene glycol (average molecular weight 5000) was added and heated to 120 ° C. The mixture was stirred for a time to obtain an electrolytic solution 2.

(Formation of white scattering layer)
(Preparation of white scattering layer coating solution)
In an aqueous solution containing 2% by mass of polyvinyl alcohol (average molecular weight 30000), 20% by mass of titanium oxide having an average particle size of 20 nm was dispersed with an ultrasonic disperser to obtain a white scattering layer coating solution.

(Formation of white scattering layer 1)
A white scattering layer coating solution is screen-printed on the electrode 2 so that the average film thickness after drying is 20 μm, and then dried at 50 ° C. for 30 minutes to evaporate the solvent. The porous white scattering layer 1 was formed by heating for a period of time.

(Formation of white scattering layer 2)
On the porous conductive material layer 7, the white scattering layer coating liquid is screen-printed so that the average film thickness after drying is 20 μm, and then dried at 50 ° C. for 30 minutes to evaporate the solvent. The porous white scattering layer 2 was formed by heating at 85 ° C. for 1 hour.

<< Production of optical elements >>
After each board | substrate produced with the combination of Table 1 was bonded together using the epoxy-type cured resin, it heated and pressed and the empty cell was formed. Subsequently, each electrolyte solution shown in Table 1 was vacuum-injected into this empty cell, and the injection port was sealed with an epoxy-based ultraviolet curable resin, thereby producing display elements 1 to 14.

<< Evaluation of display element >>
(Confirmation of two-dimensional periodicity of pores in porous conductive material layer and measurement of pore diameter)
The two-dimensional periodicity of the porous conductive material layer having a two-dimensional periodicity produced by each display element was evaluated using a photographed image of the hole array using an electron microscope. Moreover, each hole diameter measured the diameter of 200 holes using the electron microscope, and calculated | required the average diameter and variation width of the hole diameter.

(Evaluation of display unevenness resistance)
A voltage of 1.5 V is applied to each of the display devices prepared above for 3 seconds to display white, then a voltage of −1.5 V is applied for 0.5 seconds to display gray, and any display element can be displayed. The reflectance at 550 nm at two locations was measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing Co., and the difference in reflectance was calculated. The calculated difference in reflectance was _ΔRGlay, and _RGlay was used as an indicator of display unevenness resistance. Here, it is assumed that the smaller the ΔR _Glay is, the less display unevenness is.

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

  As is clear from the results shown in Table 1, the display element of the present invention having a porous conductive material layer having a porous array exhibiting two-dimensional periodicity or three-dimensional periodicity is different from the comparative example in display unevenness. It turns out that it is excellent in tolerance.

It is a schematic sectional drawing which shows an example of ED display part of the display element which has a porous conductive material layer provided with the porous arrangement | sequence which shows two-dimensional periodicity. It is a schematic sectional drawing which shows an example of ED display part of the display element which has a porous conductive material layer provided with the porous arrangement | sequence which shows three-dimensional periodicity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Electrode 3 Electrolyte 4 Colloidal crystal latex particle 5 Two-dimensional periodic film 6 Porous white scattering layer 7 Conductive formation substance containing liquid 8 Porous conductive material layer with the porous arrangement | sequence which shows two-dimensional periodicity 9 Tertiary Original periodic film 10 Porous conductive material layer having a porous array exhibiting 10-dimensional periodicity

Claims (12)

Electrochemical display that has an electrolyte containing silver or a compound containing silver in the chemical structure between the counter electrodes, and generates an electric potential difference between the counter electrodes to cause dissolution and precipitation of silver. A display element, comprising a porous conductive material layer having a porous array substantially having a two-dimensional periodicity on one counter electrode. Electrochemical display that has an electrolyte containing silver or a compound containing silver in the chemical structure between the counter electrodes, and generates an electric potential difference between the counter electrodes to cause dissolution and precipitation of silver. A display element, comprising a porous conductive material layer having a porous array substantially having a three-dimensional periodicity on one counter electrode. The display element according to claim 1, wherein the counter electrode on which the porous conductive material layer is formed is a transparent electrode. The display element according to claim 3, wherein the conductive material constituting the porous conductive material layer is substantially the same compound as the transparent electrode. The display element according to claim 1, wherein the pores constituting the porous arrangement in the porous conductive material layer are substantially spherical. The display element according to claim 5, wherein the diameter of the holes constituting the porous array in the porous conductive material layer is 1.0 μm or less. The display element according to claim 6, wherein the diameter of the holes constituting the porous array in the porous conductive material layer is 500 nm or less. 8. The conductive material forming the porous conductive material layer is substantially the same material as the counter electrode on which the porous conductive material layer is formed. Item 1. A display element according to item 1. The display element according to claim 1, wherein the electrolyte is substantially liquid, and the pores of the porous conductive material layer are filled with the electrolyte solution. The electrolyte contains 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 (4). The display element according to claim 1, wherein the display element is a display element.

[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. ]
General formula (3)
R ₇ -S-R ₈
[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. 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 to each other to form a condensed ring. ] The porous conductive material layer forms a periodic film of colloidal crystal particles on the electrode side of a substrate having an electrode on the surface, and is applied with a liquid containing a conductive material layer forming substance. The display element according to claim 1, wherein the display element is formed by removing colloidal crystal particles by a baking treatment. The porous white scattering layer is provided between the porous conductive material layer and the other counter electrode not in contact with the porous conductive material layer. The display element according to any one of the above.

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