JP2005077923A - Substrate, its manufacturing method, and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate in which the corrosion or peeling of an electrode is surely prevented in a simple step, and which is suitable for an electrodeposition-type display device, and to provide its manufacturing method and a display device using the substrate. <P>SOLUTION: Water-soluble resin, such as a resin containing polyvinyl alcohol, is dissolved in water as a solvent, and a filler or pigment and dye are added to the resulting solution, as needed, to prepare a resin solution. The resin solution is applied to a base material 11, on which first electrodes 12 are formed to form a coating layer 13. The upper surfaces of the first electrodes 12 are exposed by cleaning and the coating layer 13 is formed at recessed parts 11B between the first electrodes 12 and the peripheral part 11A of the base material 11. The coating layer 13 is cured, by using a curing agent such as a silane-coupling agent. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a substrate provided with a plurality of electrodes, a manufacturing method thereof, and a display device using the same.

  A simple matrix type wiring substrate is formed by, for example, attaching a metal film made of copper (Cu) or aluminum (Al) to a substrate made of resin such as glass or plastic, and forming electrodes by a method such as etching. It is manufactured.

  In such a wiring board, the surface is generally coated with various corrosion inhibitors in order to prevent corrosion of the electrodes. For example, in order to prevent corrosion due to moisture, a method of coating with a hydrophobic molecule such as a silylating agent has been shown (for example, see Patent Document 1). In order to prevent corrosion due to oxidation, a method of coating with a benzotriazole compound, epihalohydrin-modified polyamide, or the like has been shown (for example, see Patent Document 2). In addition, a method of plating the surface of the electrode with a noble metal such as gold (Au) (see, for example, Patent Document 3), a method of plating the entire surface of the wiring board with chromium, and removing portions other than the electrode by etching (for example, Patent Document 4) is also proposed.

  In addition, there is one in which a curable resin layer is provided on the entire surface of the resin substrate (see, for example, Patent Document 5), but this improves the chemical resistance and gas barrier property of the resin substrate rather than preventing corrosion of the electrode. This is to make it happen.

  As a method for preventing the peeling of the electrode formed on the plastic substrate, for example, a method for modifying the surface of the substrate itself, such as ultraviolet treatment, plasma treatment, corona discharge treatment, alkali treatment or ozone treatment, the substrate may be a primer. A method of processing and forming a metal film thereon has also been proposed (see, for example, Patent Document 6).

In addition, in the wiring board, a surface is flattened by filling a space between electrodes with a resin. In general, a method of exposing the electrode surface by mechanical polishing after coating the entire surface of the wiring board with a resin is used. This method is often used especially in the manufacture of build-up substrates because it can provide high flatness regardless of the type of resin used. For example, a method of exposing an electrode surface by mechanical polishing after providing an insulating layer on a wiring substrate and reducing polishing scratches by dry etching (see, for example, Patent Document 7), a photosensitive material after this mechanical polishing A method of coating a polishing flaw and exposing an electrode surface by exposure and development (see, for example, Patent Document 8), and a method of realizing flattening by using a chemical mechanical polishing slurry (for example, Patent Document) 9).
Japanese Patent Laid-Open No. 5-211146 JP 2002-105672 A JP-A-5-166967 JP-A-5-102640 JP-A-10-111500 JP-A-6-122777 Japanese Patent Laid-Open No. 6-260772 JP 7-235774 A JP 11-238709 A

  However, when such a conventional wiring board is applied to an application that directly contacts an electrolytic solution containing an organic solvent such as an electrodeposition type, the following problems may occur.

(1) Particularly in the case of a resin substrate, the electrolytic solution penetrates into the substrate and swells.
(2) Particularly in the case of a resin substrate, when the electrode is attached to the substrate with an adhesive, the adhesive dissolves in the electrolyte and the electrode is peeled off.
(3) Particularly in the case of a resin substrate, impurities contained in the substrate are eluted into the electrolyte solution.
(4) In the case of manufacturing a display device by arranging two wiring boards facing each other and sealing a peripheral portion and filling a space between the two wiring substrates with an electrolytic solution, electrodes on the peripheral portion of the wiring substrate Sealing is incomplete due to the unevenness of the take-out part, and the electrolyte leaks out.
(5) When the electrode surface is plated with a noble metal, the contact portion with the substrate is difficult to be plated. For this reason, when the display device is actually driven, the contact portion between the electrode and the substrate is easily side-etched.

  Among these, the problems associated with the electrolyte penetration into the wiring board such as (1) to (3) can be avoided by using a resin substrate having high resistance to the electrolyte. However, such a resin substrate has a low affinity with an adhesive, such as a liquid crystal polymer, and is difficult to seal. In addition, when the electrode is attached to the substrate with an adhesive, when the resin substrate is bent, if the electrode is thin, the adhesive force to the substrate is reduced and the substrate is easily peeled off.

  Further, in order to avoid leakage of the electrolyte solution as in (4), it is effective to flatten the surface of the wiring board. However, the conventional flattening method by mechanical polishing is very expensive for capital investment and often does not require the flatness that can be obtained by this method.

  As a method other than mechanical polishing, a method using a photo-curing resin as used in the manufacture of color filters can be considered. In this method, the entire surface of the substrate on which the black matrix is formed is coated with a colored photo-curing resin, exposed between the black matrices through a photomask and then developed, and finally the entire surface is thermally cured. When this method is applied to a wiring board, an aligner for accurately aligning the exposed portion and a precise photomask created in accordance with the electrode pattern are required. Moreover, it is still difficult to expose the electrode surface with a sufficient area.

  Alternatively, it is also possible to apply a photo-curing resin to the wiring board, cure the resin between the electrodes by exposing the entire surface with UV light from the opposite side (back side), and wash away the uncured resin remaining on the electrodes. It is done. In this method, the electrode can be completely exposed. However, since the applicable substrate is limited to a substrate that transmits ultraviolet rays, it cannot be applied to a glass epoxy resin substrate or the majority of resin substrates.

  The present invention has been made in view of such problems, and a first object thereof is to provide a substrate that can reliably prevent corrosion or peeling of an electrode by a simple process and a method for manufacturing the same.

  A second object of the present invention is to provide a display device in which electrode corrosion or peeling from a substrate is prevented and performance is improved.

  The board | substrate by this invention is equipped with the base material in which several electrodes were formed, and the coating layer which consists of resin formed in the area | region between several electrodes. Here, the “region between the plurality of electrodes” refers to a region surrounded by the side surface of each of the plurality of electrodes and the surface of the base material between the plurality of electrodes, and is located at both ends of the plurality of electrodes. It also includes the side surface of the electrode. The coating layer only needs to be formed so as to cover at least the side surfaces of the plurality of electrodes, and is more preferably formed so as to cover the entire region between the plurality of electrodes.

  The resin is preferably water-soluble. Here, the term “water-soluble” means that not only the case where only the hydrophilic resin material is included, but also the case where the hydrophilic resin material is included as a main component and the case where the hydrophilic resin material is introduced by introducing a hydrophilic segment into the hydrophobic resin material. Includes cases where it is granted. In addition, “when a hydrophilic resin material is included as a main component” refers to a case where a hydrophilic resin material and a hydrophobic resin material are included to exhibit water solubility.

  The substrate manufacturing method according to the present invention includes a step of forming a coating layer made of a resin so as to cover at least a plurality of electrodes on a base material on which a plurality of electrodes are formed, and exposing the upper surfaces of the plurality of electrodes by washing. And a step of forming a coating layer in a region between the plurality of electrodes.

  A display device according to the present invention has a display layer between a first substrate and a second substrate, and at least one of the first substrate and the second substrate is a base material on which a plurality of electrodes are formed, And a coating layer made of a resin formed in a region between a plurality of electrodes.

  In the board | substrate by this invention, since the coating layer which consists of resin is formed in the area | region between several electrodes, the side surface of an electrode is protected by a coating layer, and side etching of an electrode is prevented.

  In the substrate manufacturing method according to the present invention, a coating layer made of a resin is formed on a base material on which a plurality of electrodes are formed so as to cover at least the plurality of electrodes. Thereafter, the upper surfaces of the plurality of electrodes are exposed by the cleaning, and a coating layer is formed in a region between the plurality of electrodes.

  In the display device according to the present invention, since at least one of the first substrate and the second substrate is the substrate according to the present invention, corrosion of the electrode or peeling from the substrate is prevented, and the performance is improved.

  According to the substrate of the present invention, since the coating layer made of resin is formed in the region between the plurality of electrodes, the side surface of the electrode is protected by the coating layer, and side etching of the electrode can be prevented. . Furthermore, since the electrode can be firmly fixed to the base material by the coating layer, peeling of the electrode can be suppressed, which is particularly suitable when a flexible base material such as a film-like base material or plastic is used. .

  According to the substrate manufacturing method of the present invention, since the upper surfaces of the plurality of electrodes are exposed by cleaning, no special device such as an aligner or a precise operation using a photomask is required, and any shape is possible. Also for these electrodes, it is possible to easily form a coating layer in a region between the electrodes and to sufficiently expose the upper surface of the electrodes.

  According to the display device of the present invention, since the substrate of the present invention is provided, electrode corrosion or peeling from the substrate can be prevented, and performance can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1 and 2 show a configuration of a display device having a substrate according to an embodiment of the present invention as a first substrate. This display device is used, for example, as an electrodeposition type display device, and includes a display layer 30 between a first substrate 10 and a second substrate 20. A sealing member 40 is provided on the peripheral edge portion 11 </ b> A of the first substrate 10. Although not shown, a drive unit is provided around the display device.

  The first substrate 10 has a plurality of striped first electrodes 12 formed on a base material 11. In the first substrate 10, there is a step between the upper surface of the first electrode 12 and the surface of the base material 11, and a coating layer 13 made of resin is formed in the interelectrode region 11 </ b> B between the first electrodes 12. Has been. The upper surface of the first electrode 12 is not covered with the coating layer 13 and is in direct contact with the display layer 30.

  The material of the base material 11 is one that does not repel the resin applied when the coating layer 13 is formed, and has an adhesive force that does not easily peel off when the coating layer 13 is cured. If there is, it will not be specifically limited. Specifically, glass, glass epoxy resin, esters such as polyethylene naphthalate and polyethylene terephthalate, cellulose esters such as polyamide, polycarbonate, and cellulose acetate, polyethers such as polyoxymethylene, polyacetal, polystyrene, polyethylene, polypropylene, and methylpentene Examples thereof include polyolefins such as polymers, polyimides such as polyimide-amide and polyetherimide, and polycycloolefins such as norbornene resins. In order to improve the coating property of the resin or to improve the adhesion to the resin, the base material 11 is a method using a treatment agent such as a surfactant or a silane coupling agent, or UV (ultraviolet radiation). ) / The surface may be modified by a method using active energy rays such as ozone or corona discharge. The base material 11 may be a rigid substrate shape that does not easily bend, or may be a film-like structure having flexibility.

  Although not shown, holes having a diameter of, for example, about 1 mm to 2 mm are provided at two locations on the diagonal periphery of the base material 11. These holes are used for injecting an electrolytic solution in a manufacturing process described later. A sealing film 14 is bonded to the entire surface of the substrate 11 opposite to the first electrode 12.

  The first electrode 12 is made of, for example, titanium (Ti), silver (Ag), gold (Au), platinum (Pt), nickel (Ni), copper (Cu), aluminum (Al), molybdenum (Mo), tungsten ( W) or a metal or alloy, silicon (Si), or a carbon material such as graphite. The first electrode 12 may be composed of a single layer, but may be composed of a plurality of layers. For example, although not shown, the first electrode 12 may be fixed to the base material 11 with an adhesive such as silver paste, epoxy resin, polyimide resin, or polyamide resin, or on the base material 11 by plating. It may be formed. Note that the first electrode 12 is drawn out of the sealing member 40 in order to connect to the drive unit.

  The covering layer 13 protects the side surface of the first electrode 12 to suppress side etching, and prevents corrosion of the first electrode 12 or peeling from the substrate 11.

  The coating layer 13 is preferably made of a water-soluble resin. Resistance to the organic solvent contained in the display layer 30 of the first substrate 10 can be increased. For example, the organic solvent contained in the display layer 30 is prevented from penetrating into the base material 11 or included in the base material 11. This is because it is possible to prevent impurities such as an ultraviolet absorber or a catalyst from being eluted into the display layer 30. Moreover, when fixing the 1st electrode 12 to the base material 11 with an adhesive agent, since an organic solvent osmose | permeates an adhesive agent, it can suppress peeling of the 1st electrode 12 by melt | dissolution or swelling of an adhesive agent. It is. Furthermore, it is because electrolyte solution can be made to gelatinize favorably when forming the display layer 30 in the manufacturing process mentioned later.

  The coating layer 13 is preferably made of a resin containing, for example, polyvinyl alcohol. Polyvinyl alcohol is also used in laundry glue, tablet capsules, or stamp glue, and water can be used as a solvent, reducing environmental impact and reducing manufacturing costs, and is suitable for mass production. is there. Polyvinyl alcohol may be partially acetylated.

  Here, the “resin containing polyvinyl alcohol” includes not only the case of containing only polyvinyl alcohol but also the case of containing polyvinyl alcohol as a main component, that is, the case of containing water and including polyvinyl alcohol and a hydrophobic resin material. .

  Moreover, the coating layer 13 may be comprised with resin containing water-based acrylic resin or amino resin. Examples thereof include polyacrylamide, polyethylene oxide, methyl vinyl ether / maleic acid / cross polymer, and carboxy vinyl polymer. Moreover, you may be comprised by what provided the water-solubility by introduce | transducing the hydrophilic segment into hydrophobic resin material.

  Here, the “water-based acrylic resin or amino resin-containing resin” means not only the case of containing only the water-based acrylic resin or amino resin, but also the case of containing the water-based acrylic resin or amino resin as a main component, that is, the water-based acrylic resin or amino resin. Including the case of including a resin and a hydrophobic resin material and exhibiting water solubility.

  The degree of polymerization of these resins is not particularly limited, but as the molecular weight increases, the solubility in a solvent decreases and the viscosity increases. For this reason, when it is desired to increase the filling rate of the resin in the interelectrode region 11B between the first electrodes 12 to increase the flattening rate of the first substrate 10, the covering layer 13 can be formed of a resin with a low polymerization degree. preferable. The flattening rate referred to here is the difference between the lowest portion (curved bottom) of the top surface of the coating layer 13 and the top surface of the first electrode 12 from the step S1 between the top surface of the first electrode 12 and the surface of the substrate 11. The value obtained by subtracting the step S2 is obtained by dividing the value obtained by the step S1 between the upper surface of the first electrode 12 and the surface of the substrate 11 and multiplying the obtained value by 100.

  For example, when the coating layer 13 is composed of a resin containing polyvinyl alcohol, when water is used as a solvent for dissolving the resin in the manufacturing process described later, the saponification degree of the resin is 70 mol% or more and 100 mol% or less. Is preferred. In general, the higher the degree of saponification, the higher the water solubility, and the lower the solubility, the higher the solubility in a water-soluble organic solvent such as alcohol. Therefore, when water is used as a solvent for dissolving the resin, dissolution can be easily performed by using a resin having a high saponification degree. Conversely, when alcohols such as methanol are used as the solvent for dissolving the resin, the saponification degree of the resin is preferably greater than 0 mol% and not greater than 50 mol%.

  The covering layer 13 may contain a filler (filler). By including the filler, the mechanical strength of the coating layer 13 can be increased, and the dimensional stability against heat shrinkage can be improved. In addition, the effect of preventing penetration of the electrolyte from the display layer 30 can be increased, and the amount of resin used can be reduced. Examples of fillers include titanium oxide, potassium titanate, zircon oxide, zinc sulfide, antimony oxide, zinc oxide, magnesium oxide, barium sulfate, calcium sulfate, talc, alumina, calcium carbonate, kaolin clay, mica, magnesium hydroxide , Calcium sulfate, bentonite, calcium sulfate, anhydrous silicic acid, basic magnesium carbonate, hydrotalcite, hydrous calcium silicate, quartz glass, diatomaceous earth, carbon, or silica. Two or more of these may be used in combination.

  Furthermore, it is preferable that the coating layer 13 contains at least one of a pigment and a dye. This is because by coloring the coating layer 13 with a pigment or dye, the exposure of the first electrode 12 can be identified visually when the upper surface of the first electrode 12 is exposed by washing in the manufacturing process described later. Moreover, it is because it is also possible to provide the coating layer 13 with an ultraviolet shielding ability by containing a pigment or a dye in the coating layer 13.

  In addition, when the coating layer 13 is comprised with water-soluble resin, coloring with dye is very easy. Further, if the color of the coating layer 13 is different from the surface of the first electrode 12, it is convenient for identifying the exposure of the first electrode 12, but there is no particular limitation. Since many of the exemplified water-soluble resins are colorless and transparent, or similar, they can be colored in any color with a pigment or dye. The content of the pigment or dye is not particularly limited.

  Examples of the pigment include organic pigments such as azo pigments, phthalocyanine pigments, dioxazine pigments, quinacridone pigments, anthraquinone pigments, and benzimidazolone pigments. In addition, in the case of inorganic pigments, the above-mentioned fillers can be used as coloring pigments, and titanium (Ti), antimony (Sb), chromium (Cr), nickel (Ni), iron (Fe), zinc (Zn) , Cobalt (Co), Aluminum (Al), Silicon (Si), Copper (Cu), Manganese (Mn), Lithium (Li), Phosphorus (P), Calcium (Ca) or Tin (Sn) Many are already manufactured and marketed. These pigments can be used alone or as a mixture of a plurality of types, and can be subjected to a surface treatment with a surfactant, a silane coupling agent or the like, if necessary.

  The coating layer 13 preferably includes a silane coupling agent having an amine group or an amide group as a functional group. This is because an amine group or an amide group is introduced into the coating layer 13, and good adhesiveness is obtained between the coating layer 13 and the display layer 30 or between the coating layer 13 and the sealing member 40. Such a silane coupling agent also has a role as a crosslinking agent for curing the coating layer 13 in, for example, a manufacturing process described later.

  The covering layer 13 is preferably also formed on the peripheral edge portion 11 </ b> A of the base material 11. This is because, in the manufacturing process, the coating layer 13 may be formed on the entire surface of the substrate 11, and patterning is not required and the process is simplified. Moreover, the affinity between the sealing member 40 provided on the peripheral portion 11A and the base material 11 is enhanced, the sealing performance of the sealing member 40 is improved, and the display is performed between the sealing member 40 and the coating layer 13. This is because the organic solvent in the layer 30 can be effectively prevented from leaking out. Furthermore, the sealing performance of the sealing member 40 can be further improved by increasing the planarization rate of the surface of the first substrate 10 by adjusting the viscosity of the resin that is the material of the coating layer 13. .

  The sealing film 14 seals a hole for injecting an electrolytic solution. The sealing film 14 also has a function of imparting a gas barrier property to the base material 11 when the base material 11 is made of a flexible material such as plastic. The sealing film 14 has, for example, a configuration in which a thin film having a high gas barrier property and a cover film are bonded together through an adhesive layer such as a double-sided adhesive film. Examples of the thin film having a high gas barrier property include an aluminum foil, a film obtained by vapor-depositing silica on the surface of a plastic film, or an ethylene vinyl alcohol polymer. Examples of the cover film include a release film such as a film coated with PTFE (polytetrafluoroethane) or a release agent. In addition, the sealing film 14 does not necessarily need to be provided in the whole surface of the base material 11, and may be provided only on the hole for inject | pouring electrolyte solution.

  The second substrate 20 is a substrate on the display side, and has a configuration in which a plurality of striped second electrodes 22 are provided on a base material 21.

  The substrate 21 is made of a transparent material, specifically, quartz glass or the like. In addition to this, for example, the base 11 may be made of the same synthetic resin. Similarly to the base material 11, the base material 21 may have a rigid substrate shape that does not bend easily, or may be a film-like structure having flexibility. The surface of the base 21 on the second electrode 22 side is made of, for example, silylating agent / HMDS (1,1,1,3,3,3-hexamethyldisilazane) in order to improve the adhesion with the display layer 30. After adhering by a method such as spin coating or spraying, it may be heated and dried by, for example, a hot plate or an oven.

The second electrode 22 functions as a deposition substrate on which a metal to be displayed as a pixel is deposited, and is composed of, for example, a transparent conductive film. Specifically, indium oxide (In ₂ O ₃ ), tin oxide (SnO ₂ ), ITO (Indium Tin Oxide) that is an oxide of tin (Sn) and indium (In), or tin or It is preferably composed of a material doped with antimony (Sb) or the like. Moreover, you may comprise with magnesium oxide (MgO) or zinc oxide (ZnO). Note that the second electrode 22 is drawn out of the sealing member 40 in order to connect to the drive unit.

  The display layer 30 includes, for example, an electrolyte and a precipitation-dissolving material that is precipitated and dissolved by an oxidation-reduction reaction.

  The electrolyte contains a polymer material, an electrolyte salt, and, if necessary, a solvent as a plasticizer. Examples of the polymer material include polyethylene oxide, polypropylene oxide, polyethyleneimine, and polyethylene sulfide. These may be branched with the main chain structure. Further, polymethyl methacrylate, polyvinylidene fluoride, polyvinylidene chloride or polycarbonate may be used. These polymer materials may be used alone or in combination of two or more. In addition, a polymerizable functional group such as an acrylic group may be bonded to these polymer materials.

The electrolyte salt is for increasing the ionic conductivity of the display layer 30 so that the precipitation dissolution reaction of the precipitation dissolution material can be performed more effectively and stably. Examples of the supporting electrolyte salt include lithium salts such as LiCl, LiBr, LiI, LiBF ₄ , LiClO ₄ , LiPF _{6, and} LiCF ₃ SO ₃ , potassium salts such as KCl, KI, and KBr, or NaCl, NaI, or Sodium salts such as NaBr, or tetraalkyl quaternary ammonium salts such as tetraethylammonium borofluoride, tetraethylammonium perchlorate, tetrabutylammonium borofluoride, tetrabutylammonium perchlorate or tetrabutylammonium halide salt Can be mentioned. Any 1 type may be used for electrolyte salt and it may use it in mixture of 2 or more types.

  Examples of the solvent include hydrophilic ones such as water, ethyl alcohol, isopropyl alcohol, or mixtures thereof, or propylene carbonate, dimethyl carbonate, ethylene carbonate, γ-butyrolactone, acetonitrile, sulfolane, dimethoxyethane, ethyl alcohol. , Isopropyl alcohol, dimethylformamide, dimethyl sulfoxide, dimethylacetamide, N-methylpyrrolidone, or a mixture thereof having a hydrophobic property.

  The precipitation-dissolving material is for enabling display of pixels by utilizing the change in color between the precipitated state and the dissolved state. Examples of the precipitation-dissolving material include metal ions that precipitate as a metal upon reduction. Although it does not specifically limit as a metal ion, For example, a bismuth ion, copper ion, silver ion, sodium ion, lithium ion, iron ion, chromium ion, nickel ion, or cadmium ion is mentioned. Among them, particularly preferable metal ions are bismuth ions or silver ions, and more preferable are silver ions. Bismuth ions and silver ions can easily proceed with a reversible reaction and have a high degree of discoloration during precipitation. In particular, silver ions have an ionic valence of usually 1, so that the ionic valence is usually 3. This is because, compared with a certain bismuth ion, the amount of charge required to reduce one atom to a metal is one third. The metal ion is added to the solvent as a metal salt, for example. Examples of the metal salt include silver nitrate, silver borofluoride, silver halide, silver perchlorate, silver cyanide, and silver thiocyanide as long as they are silver salts. Any 1 type may be used for a metal salt, and 2 or more types may be mixed and used for it.

  The display layer 30 may also contain a colorant and various additives as necessary.

  The colorant is for improving contrast. Examples of the colorant include inorganic pigments and organic pigments, and these may be used alone or in combination. For example, when the precipitation color from the electrolyte solution composition used in the present embodiment is black, such as silver, a white material having high concealability is preferable. As such a material, for example, inorganic particles such as titanium oxide, calcium carbonate, silicon oxide, magnesium oxide or aluminum oxide can be used. Moreover, a pigment | dye can also be used.

  The sealing member 40 is for sealing a space between the first substrate 10 and the second substrate 20, and also serves as a spacer. The sealing member 40 may be, for example, a film-like member such as a thermoplastic resin film or a thermosetting resin film, and may be formed by applying an ultraviolet curable resin in a frame shape with a dispenser. The sealing member 40 may be composed of a single layer, but may be composed of a plurality of layers, such as forming an adhesive layer on both surfaces of the core material.

  This display device can be manufactured, for example, as follows.

  FIG. 3 shows a manufacturing process of the display device according to the present embodiment. First, for example, a resin containing polyvinyl alcohol having a saponification degree adjusted as described above is prepared. This resin is dissolved in water as a solvent to form a varnish, and the above-described filler, pigment or dye is added as necessary to prepare a resin solution for forming the coating layer 13.

  At this time, instead of adjusting the saponification degree of the resin containing polyvinyl alcohol, the solubility of the solvent used for dissolving the resin may be adjusted. For example, when the step S1 between the upper surface of the first electrode 12 and the surface of the substrate 11 is small, if the solubility of the resin is too high, the coating layer 13 that covers the upper surface of the first electrode 12 is subsequently dissolved and removed by washing. At this time, the coating layer 13 in the interelectrode region 11B may flow out, or conversely, the coating layer 13 eluted from the interelectrode region 11B may cover the upper surface of the first electrode 12 again. For this reason, the surface of the 1st electrode 12 is left in the state which left the coating layer 13 of the interelectrode area | region 11B by mixing water and water-soluble organic solvents, such as alcohol, by a suitable ratio, and adjusting the solubility of resin. It can be sufficiently exposed.

  When the resin is dissolved in water, an organic solvent may be added in order to improve the solubility of the resin and the coating property to the substrate 11. The organic solvent used may be water-soluble, and alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, t-butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol, Ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol Monobutyl ether, triethylene glycol monomethyl Glycols such as ether, triethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, Amines such as morpholine, N-ethylmorpholine, ethylenediamine, diethylenetriamine, triethylenetetramine, polyethyleneimine, tetramethylpropylenediamine, amides such as formamide, N, N-dimethylformamide, N, N-dimethylacetamide, 2-pyrrolidinone Pyrrolidinones such as N-methyl-2-pyrrolidinone and N-vinyl-2-pyrrolidinone It is possible. In addition, polar solvents such as dimethyl sulfoxide, sulfolane, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, acetonitrile, and acetone can also be used. Two or more of these may be used in combination.

  Moreover, in order to improve the affinity with respect to the base material 11, you may mix the water-soluble organic solvent mentioned above or a leveling agent with the resin solution.

  Next, as shown in FIG. 3A, the above-described resin solution is applied to the base material 11 on which the first electrode 12 is formed, thereby forming the coating layer 13. As a coating method, an appropriate method can be used according to the viscosity of the resin solution or according to the thickness of the coating layer 13. For example, when the resin solution has a low viscosity, spin coating or dipping can be used, and when the resin solution has a high viscosity, a coating apparatus or instrument such as a bar coater, a table coater, or a spatula can be used.

  When applying the resin solution to the base material 11, repellency may occur depending on the material and surface state of the base material 11. In order to prevent this, the substrate 11 may be appropriately subjected to a surface treatment. As the surface treatment method, ultraviolet treatment, plasma treatment, corona discharge treatment, alkali treatment, ozone treatment, or the like can be used. In addition, chemical treatment such as alkali treatment or oxidation treatment may be performed. As a method of the oxidation treatment, there is a method of immersing in an aqueous solution of potassium dichromate in sulfuric acid.

  Moreover, in order to improve the affinity with respect to the base material 11 of a resin solution, the method of processing the base material 11 with a silane coupling agent or a silylating agent can also be taken.

  After forming the coating layer 13 on the surface of the substrate 11, the coating layer 13 is temporarily cured by heating the substrate 11 for an extremely short time with an oven or a hot plate to volatilize the solvent. The drying temperature may be in a range that promotes the volatilization of the solvent. In the case where there is a risk of distortion due to heating, such as the base material 11 made of plastic, the solvent may be volatilized appropriately using a reduced pressure.

  After the cover layer 13 is temporarily cured, as shown in FIG. 3B, the upper surface of the first electrode 12 is exposed by cleaning, and the cleaning is stopped when the upper surface of the first electrode 12 is exposed. Thereby, the coating layer 13 is formed in the inter-electrode region 11 </ b> B between the first electrodes 12 and the peripheral portion 11 </ b> A of the base material 11. Whether or not the upper surface of the first electrode 12 is exposed may be detected using a tester or the like while being washed, or may be visually identified when the coating layer 13 contains a pigment or dye. Is also possible.

  As the cleaning liquid, water or an organic solvent heated appropriately is used as necessary. Normally, the higher the temperature of the cleaning liquid, the higher the speed at which the coating layer 13 is dissolved. Therefore, the temperature of the cleaning liquid and the cleaning time are adjusted according to the degree to which the upper surface of the first electrode 12 is exposed. A small amount of an organic solvent may be added to the cleaning liquid in order to adjust the cleaning speed. The organic solvent added at this time may be any water-soluble one. Specific examples include, for example, increasing the solubility of the resin when dissolving the resin in water to prepare the resin solution. For this purpose, the organic solvent added is the same as that exemplified. In addition, when performing precise cleaning such as controlling the degree of exposure of the first electrode 12, a method of delaying the dissolution rate by adding an organic solvent having low resin solubility can be employed. For example, when the coating layer 13 is made of a resin containing polyvinyl alcohol, as the cleaning liquid, for example, a mixture of water and methanol with a adjusted ratio is used, or only water or only methanol is used. The solubility of the resin in the cleaning solution can be adjusted. The relationship between the degree of saponification of polyvinyl alcohol, the water / methanol mixing ratio, and the solubility is publicly disclosed through materials provided by chemical manufacturers or material manufacturers.

  As a cleaning method, in addition to a method using a spray or a shower, the first substrate 10 may be immersed in a container containing a cleaning solution, and ultrasonic waves may be applied or vibrations may be applied as appropriate. Alternatively, the surface of the first substrate 10 may be rubbed with a cloth, sponge or brush impregnated with a cleaning solution, or may be struck with a brush.

  After stopping washing, the coating layer 13 is cured by crosslinking with a crosslinking agent. Thereby, the strength of the covering layer 13 can be increased and resistance to the display layer 30 can be imparted.

  The cross-linking agent only needs to react with the side chain functional group of the water-soluble resin, such as a hydroxy group in polyvinyl alcohol, and can be used in water, a water-soluble organic solvent, or a mixture of water and a water-soluble organic solvent. It must be soluble.

  As the crosslinking agent, for example, a silane coupling agent that dissolves in water or a water-soluble organic solvent is preferable. Examples include N-β (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β (aminoethyl) -γ-aminopropyltriethoxy. Silane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, aminosilane, and other amino-based ones, β- (3,4-epoxycyclohexyl) ethyltri Epoxy compounds such as methoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyl Vinyl-based such as triethoxysilane There is something. Epoxy silane coupling agents are easily dissolved when water is prepared to be weakly acidic with acetic acid or the like. Vinyl-based materials can be used by dissolving in a water-soluble organic solvent. Of these, amino silane coupling agents having high solubility in water are particularly preferably used. These silane coupling agents may be added as they are, or those that have been hydrolyzed in advance may be added.

  Other than silane coupling agents, urea compounds such as urea, allyl urea, carbamyl urea, N-formyl urea, dimethylol urea, glyoxal, aldehydes such as formaldehyde and glutaraldehyde, malonaldehyde tetramethyl acetal, glutaraldehyde tetramethyl acetal Such as acetals, carbodiimide resins provided with hydrophilic segments, water-soluble resins or oligomers having two or more carboxyl groups, water-soluble dicarboxylic acids, water-soluble isocyanates, acrylonitrile, and the like can be used.

  The amount of these crosslinking agents added can be adjusted depending on the degree of saponification of the resin used and the hardness of the target coating layer 13, but is usually 0.1% to 5% by weight based on the resin weight. What is necessary is just to mix | blend. In order to promote the cross-linking reaction, a catalyst may be appropriately mixed. As the type of catalyst, various types of acidic catalysts such as inorganic acids and organic acids and organic tin compounds can be used.

  The crosslinking agent not only cures the coating layer 13 but also has an effect of introducing a functional group different from the resin into the coating layer 13. Thereby, the adhesiveness of the display layer 30 and the coating layer 13 and the adhesiveness of the sealing member 40 and the coating layer 13 can be improved. For this purpose, it is preferable to use, for example, a silane coupling agent having an amine group or an amide group as a functional group as the crosslinking agent.

  The crosslinking agent may be made to adhere to the coating layer 13 and then impregnated into the coating layer 13 to allow the crosslinking to proceed by heating. Alternatively, a resin solution to which a crosslinking agent has been added in advance may be applied to the substrate 11. After the coating layer 13 is formed by coating, crosslinking may be advanced by heating. Furthermore, these methods may be used in combination.

  As a method for attaching the cross-linking agent to the coating layer 13, there are methods such as coating with a cloth or sponge, spraying, exposure to steam, immersion, spin coating, and the like. The crosslinking agent may be used alone, or may be used in a state dissolved in water or a water-soluble organic solvent as necessary.

  A normal heating device such as an oven, a hot plate, or an infrared heater can be used for heating. The heating temperature is not particularly limited, but the solvent can be volatilized, the reaction between the resin and the crosslinking agent can be promoted, and the coating layer 13 can be prevented from being adversely affected. A good coating layer 13 can be obtained at about ° C.

  After the coating layer 13 is cured, the surface of the first substrate 10 is appropriately cleaned, and residues such as resin and cross-linking agent remaining on the upper surface of the first electrode 12 are removed by spray cleaning or buffing. The upper surface of one electrode 12 is sufficiently exposed. Thereby, the 1st board | substrate 10 which is a board | substrate which concerns on this Embodiment is completed.

  After forming the first substrate 10, as shown in FIG. 1, the sealing member 40 is disposed on the peripheral portion 11 </ b> A of the base material 11, and the first electrode 12 and the second electrode 22 are orthogonal to each other. The first substrate 10 and the second substrate 20 are overlapped and bonded by the sealing member 40.

  After that, for example, the above-described polymer material, electrolyte salt and, if necessary, a solvent and a precipitation-dissolving material are mixed, and an electrolytic solution to which a colorant and various additives are further added as necessary is used as the first substrate 10. The holes (not shown) are injected into the space between the first substrate 10 and the second substrate 20 and heated. As a result, the display layer 30 including the electrolyte and the precipitated dissolved material is formed. At this time, when a polymer functional material such as an acrylic group is used as the polymer material described above, the electrolyte is formed by gelling the electrolytic solution with active energy rays or heat. You can also.

Moreover, the sealing film 14 is produced. For example, the sealing film 14 is formed by laminating a double-sided adhesive film on a thin film having a high gas barrier property made of the above-described material, and placing a cover film made of the above-mentioned material on the thin film, for example, by a laminator method using a roll laminator. It can be formed by bonding. The roll laminator conditions can be set as follows, for example.
Roller (up / down) temperature: 140 ° C
Linear pressure: 3.3 kg / cm
Laminating speed: 0.5m / min

  Prior to use, the sealing film 14 is peeled off and overlaid on the entire surface of the first substrate 10, and is bonded by heat pressing, for example, under conditions of 140 ° C., 0.2 MPa, 4 seconds. Thus, the display device shown in FIG. 1 is completed.

  In this display device, when a predetermined voltage is applied between the first electrode 12 and the second electrode 22, the metal ions in the display layer 30 existing between the first electrode 12 and the second electrode 22. Moves to the second electrode 22, metal ions are reduced at the second electrode 22, metal is deposited on the second electrode 22, and writing is performed. The deposited metal is recognized as an image through the base material 21 of the second substrate 20. On the other hand, when a predetermined reverse voltage is applied between the first electrode 12 and the second electrode 22, the metal deposited on the second electrode 22 is oxidized and dissolved as metal ions in the display layer 30 to be erased. Is done.

  Thus, in this embodiment, since the coating layer 13 made of resin is formed in the interelectrode region 11B between the first electrodes 12, the side surface of the first electrode 12 is protected by the coating layer 13, Side etching of the first electrode 12 can be prevented, and the performance of the display device can be improved. Furthermore, since the 1st electrode 12 can be firmly fixed to the base material 11 by the coating layer 13, peeling of the 1st electrode 12 can be suppressed, and flexible materials, such as a film-like base material 11 and a plastics, are especially good. This is suitable when a certain base material 11 is used.

  In the present embodiment, since the upper surface of the first electrode 12 is exposed by cleaning, a special device such as an aligner or a precise operation using a photomask is not required, and any shape of the first electrode 12 can be obtained. Also for the one electrode 12, the coating layer 13 can be easily formed in the interelectrode region 11B between the first electrodes 12, and the upper surface of the first electrode 12 can be sufficiently exposed.

  In particular, in the present embodiment, since the coating layer 13 is made of a water-soluble resin, the resistance of the first substrate 10 to the display layer 30 can be increased, and the display layer 30 containing an organic solvent is directly touched. However, the penetration of the organic solvent into the substrate 11 or the elution of impurities from the substrate 11 can be prevented. Therefore, the base material 11 with poor resistance to an organic solvent such as a glass epoxy resin can be employed, the selection range of the material of the base material 11 is widened, and the high-performance first substrate 10 is realized at low cost. Can do. Moreover, it is possible to prevent the organic solvent from penetrating into the adhesive that fixes the first electrode 12 to the substrate 11, and to suppress the peeling of the first electrode 12 due to the dissolution or swelling of the adhesive.

  In particular, in the present embodiment, since the coating layer 13 is made of a resin containing polyvinyl alcohol, water can be used as a solvent, the environmental load is small, the manufacturing cost is reduced, and mass production is possible. Are suitable.

  In addition, in particular, in the present embodiment, since the coating layer 13 is also formed on the peripheral edge portion 11A of the base material 11, the affinity between the sealing member 40 and the base material 11 is enhanced, and the sealing member The sealing performance of 40 can be improved.

  Further, specific embodiments of the present invention will be described in detail.

[Example 1-1] (low polymerization degree, glass electrode substrate, large flattening rate)
<Fabrication of first substrate>
The first substrate 10 shown in FIGS. 1 and 3 was produced. At this time, the coating layer 13 was composed of a resin having a low polymerization degree.

  Specifically, first, polyvinyl alcohol partially saponified to 88 mol% (“GOHSENOL GL-05 (trade name / product number)” manufactured by Nippon Synthetic Chemical Industry Co., Ltd .; average polymerization degree 500) · 12.5 g in distilled water 20 g After dissolving, a few drops of red water-based ink (manufactured by Pilot) for a fountain pen were added to prepare a resin solution. When the viscosity of this resin solution was measured with a rotational viscometer, it was 45,000 mPa · s (rotation speed: 0.5 rpm, 25 ° C.).

  Moreover, the base material 11 which consists of glass in which the 1st electrode 12 was formed was prepared. The first electrode 12 is formed by plating a 12 μm thick copper (Cu) layer on the entire surface of one side of the substrate 11 and then patterning it into a predetermined shape. On top of this, a nickel (Ni) layer having a thickness of 5 μm is formed. A gold (Au) layer having a thickness of 0.1 μm and a silver (Ag) layer having a thickness of 3 μm are formed in this order by plating. The width of the first electrode 12 was 200 μm, the interval was 300 μm, and the height was 45 μm. That is, the step S1 between the upper surface of the first electrode 12 and the surface of the substrate 11 was 45 μm.

  Subsequently, the prepared resin solution was applied to the base material 11 on which the first electrode 12 was formed with a silicon rubber spatula (thickness 5 mm) to form a coating layer 13 (see FIG. 3A). . This was put in an oven, heated and dried at 100 ° C. for 5 minutes, and temporarily cured.

  After that, a gauze (“Bencot (trade name)” manufactured by Asahi Kasei Co., Ltd.) is wound on a slide glass and impregnated with a methanol / water = 1/1 mixed solution, and the base material extends in the extending direction of the first electrode 12. 11 was wiped to expose the upper surface of the first electrode 12 (see FIG. 3B). The surface was observed with a microscope with a magnification of 50 times, and the red color of the colored polyvinyl alcohol aqueous solution disappeared from the upper surface of the first electrode 12 to confirm the exposure of the first electrode 12.

  Subsequently, a γ-aminopropyltriethoxysilane (“KBE-903 (product number)” manufactured by Shin-Etsu Chemical Co., Ltd.)) / Distilled water = 5/1 (weight ratio) mixed solution as a silane coupling agent on the surface of the substrate 11 Sprayed with a nebulizer. This was put in an oven and heated at 100 ° C. for 30 minutes to cure the coating layer 13. After that, the surface was lightly wiped with a sponge in running water, and the resin residue on the first electrode 12 was washed away. Thereby, the first substrate 10 shown in FIG. 1 was obtained.

  The level difference of the obtained first substrate 10 was measured with a contact-type level meter and the flattening rate was determined to be 89%. This value was obtained as described in the embodiment. Specifically, from the step S1 (45 μm) between the upper surface of the first electrode 12 and the surface of the substrate 11, the step S2 (the curved bottom) of the upper surface of the covering layer 13 and the surface of the substrate 11 ( 5 μm) was subtracted, and the obtained value was divided by the step S 1 between the upper surface of the first electrode 12 and the surface of the substrate 11, and the obtained value was further multiplied by 100.

<Solvent resistance test>
About the obtained 1st board | substrate 10, the tolerance with respect to the organic solvent used as electrolyte solution was investigated. Specifically, γ-butyrolactone was poured into a stainless steel container and the first substrate 10 was completely immersed. Covered with aluminum foil and placed in an oven and heated at 100 ° C. After 4 hours, the first substrate 10 was taken out, washed thoroughly with ethanol, and dried using an air gun. When the weight change of the first substrate 10 was measured, it was + 0.9%. Moreover, when the surface of the 1st board | substrate 10 was confirmed visually, peeling of the 1st electrode 12 and melt | dissolution of the coating layer 13 were not seen.

[Example 1-2]
Except that dimethyl sulfoxide was used instead of γ-butyrolactone, a solvent resistance test was performed in the same manner as in Example 1-1, and the change in the weight of the first substrate 10 was measured to be + 2.8%. . Moreover, when the surface of the 1st board | substrate 10 was confirmed visually, although melt | dissolution was partly produced in the contact part vicinity of the 1st electrode 12 and the base material 11, melt | dissolution of the coating layer 13 was not seen.

[Example 1-3]
<Preparation of empty cell>
A first substrate 10 was produced in the same manner as in Example 1-1. A three-layer adhesive film (55 μm thickness, manufactured by Aichi Plastics Co., Ltd.) punched into an outer shape of 30 mm × 40 mm and a width of 5 mm was stacked on the peripheral edge portion 11A of the obtained first substrate 10 as a sealing member 40. Moreover, the 2nd board | substrate 20 with which the width | variety 250 micrometers and the 2nd electrode 22 with a space | interval of 250 micrometers which consist of ITO were formed in the base material 21 of external shape 40 mm x 30 mm was prepared. The second substrate 20 is placed on the first substrate 10 on which the sealing member 40 is disposed so that the first electrode 12 and the second electrode 22 are orthogonal to each other, and 140 ° C., 0.2 MPa, 3 seconds. Heat press was performed under the conditions of Thus, an empty cell having the same configuration as that of the display device shown in FIG. 1 was produced except that the display layer 30 was not provided.

<Adhesion test>
The obtained empty cell was immersed in a stainless steel container poured with γ-butyrolactone in the same manner as in Example 1-1 and completely immersed with a weight from above. The container was covered with aluminum foil, placed in an oven, and heated at 100 ° C. After 4 hours, the empty cell was taken out, washed with ethanol, and ethanol was blown off with an air gun. Moreover, when the empty cell was observed visually, peeling of the sealing member 40 was not confirmed at all.

[Example 1-4]
<Production of display device for side etching test>
A first substrate 10 was produced in the same manner as in Example 1-1. A sealing member 40 similar to that of Example 1-3 was stacked on the peripheral edge portion 11 </ b> A of the obtained first substrate 10.

Moreover, the electrolyte solution for forming the display layer 30 was prepared. Specifically, first, the following components were dissolved in γ-butyrolactone as a solvent at each blending amount.
Silver iodide: 500 mmol / l
Sodium iodide: 750 mmol / l
Triethanolamine: 67 mmol / l
Coumarin: 5g / l
Next, 1/5 weight resin solution ("TA-140 (product number)" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was mixed with this. Subsequently, as a white pigment, titanium oxide (“JR-805 (product number)” manufactured by Titanium Industry Co., Ltd.) having an equal weight to this solution was added and dispersed with a homogenizer. The pressure was reduced with a pump, and the pressure was released when bubbles no longer emerged from the pigment dispersion, after which organic oxide (“Perocta O (trade name)” manufactured by NOF Corporation) was added to 2 wt% of the resin liquid. The solution was added and stirred gently to prevent bubbles from entering to obtain an electrolyte solution.

  Subsequently, an empty cell was produced in the same manner as in Example 1-3. At that time, the first substrate 10 used was provided with holes having a diameter of 1 mm at two locations on the diagonal periphery in the region surrounded by the sealing member 40. About the obtained empty cell, pressure injection was performed using the syringe from one hole of the first substrate 10 until the electrolyte overflowed from the other hole. After that, wipe the electrolyte solution above the holes with a cloth soaked with ethanol, temporarily seal each hole with cellophane, and gel the electrolyte solution by heating at 100 ° C. for 10 minutes in an oven. A display layer 30 containing an electrolyte and a deposited dissolution material was formed. Subsequently, the cellophane tape was peeled off, and the sealing film 14 was placed on the entire back side of the substrate 11 and heat pressed under conditions of 140 ° C., 0.2 MPa, and 3 seconds. Thereby, the display device shown in FIG. 1 was produced.

<Side etching test>
With respect to the obtained display device, electrode wiring for driving was performed, and writing, holding, erasing, and holding were performed under the following driving conditions as one cycle, and 10,000 cycles were repeatedly responded.

Driving condition Writing condition: -2.0V, 0.10 seconds,
Holding conditions: 0.0V, 12.00 seconds,
Erase conditions: + 2.8V, 0.12 seconds,
Holding condition: 0.0V, 12.00 seconds was defined as one cycle.

  After that, the display device was disassembled, the first substrate 10 was washed with ethanol, and the surface of the first electrode 12 was observed with a microscope. As a result, irregularities associated with silver precipitation / dissolution were formed on the first electrode 12. No changes were seen except for what was occurring.

[Comparative Example 1-1]
<Solvent resistance test>
The base material on which the same first electrode as used in Example 1-1 was formed was subjected to a solvent resistance test in the same manner as in Example 1-1 without forming a coating layer. When the surface of the base material was visually confirmed, partial peeling was observed on more than half of the first electrodes.

[Comparative Example 1-2]
A solvent resistance test was conducted in the same manner as in Comparative Example 1-1 except that dimethyl sulfoxide was used instead of γ-butyrolactone, and the surface of the substrate was visually confirmed. As a result, it was the same as in Comparative Example 1-1. Results were obtained.

[Comparative Example 1-3]
<Adhesion test>
A base material on which the same first electrode as used in Example 1-1 was formed, and an empty cell was produced in the same manner as in Example 1-3 without forming a coating layer. When this empty cell was subjected to a solvent resistance test in the same manner as in Example 1-3, peeling occurred between the sealing member and the substrate, and the empty cell was decomposed during the test.

[Comparative Example 1-4]
<Side etching test>
A base material on which the same first electrode as used in Example 1-1 was formed, and a display device was produced in the same manner as in Example 1-4 without forming a coating layer. About the obtained display apparatus, the electrode wiring for a drive was performed and the 10,000-cycle repeated response was performed like Example 1-4. After disassembling the display device and washing the substrate with ethanol, the surface of the first electrode was observed with a microscope. In addition to the irregularities associated with silver deposition / dissolution at the top of the first electrode, It was observed that deep erosion occurred mainly in the vicinity of the contact portion between one electrode and the substrate, and the internal copper was exposed.

  As can be seen from Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-4, in Examples 1-1 to 1-4 in which the coating layer 13 is provided, a comparative example in which the coating layer 13 is not provided. Compared to 1-1 to 1-4, the resistance to organic solvents, the adhesion of the sealing member, and the resistance to side etching were all high. That is, it was found that the corrosion and peeling of the first electrode 12 can be prevented by providing the covering layer 13.

[Example 2] (Medium polymerization degree, glass electrode substrate)
<Fabrication of first substrate>
A first substrate 10 was produced in the same manner as in Example 1-1, except that the covering layer 13 was made of a resin having a medium polymerization degree.

  First, polyvinyl alcohol partially saponified to 80 mol% (“GOHSENOL KH-20 (trade name / product number)” manufactured by Nippon Synthetic Chemical Industry Co., Ltd .; average polymerization degree 2,000) · 2 g was dissolved in 20 g of distilled water, and a fountain pen A few drops of red aqueous ink (manufactured by Pilot) was added to prepare a resin solution. When the viscosity of this resin solution was measured with a rotational viscometer, it was 1,600 mPa · s (rotation speed: 0.5 rpm, 25 ° C.).

  A base material 11 made of glass on which the same first electrode 12 as in Example 1-1 was prepared, and the prepared resin solution was subjected to spin coating (rotation speed: 2,000 rpm, 25 ° C., 20 seconds, 3 seconds). , 000 rpm, 25 ° C., 20 seconds), and applied to the substrate 11 to form a coating layer 13 (see FIG. 3A). This was put into an oven, heat-dried at 100 ° C. for 5 minutes, and temporarily cured.

  After that, the upper surface of the first electrode 12 was exposed by applying methanol spray to the surface of the substrate 11 (see FIG. 3B). The surface was observed with a microscope with a magnification of 50 times, and the red color of the colored polyvinyl alcohol aqueous solution disappeared from the upper surface of the first electrode 12 to confirm the exposure of the first electrode 12.

  Subsequently, the coating layer 13 was cured in the same manner as in Example 1-1 to obtain the first substrate 10 shown in FIG. The level difference of the obtained first substrate 10 was measured with a contact-type level meter, and the flattening rate was determined in the same manner as in Example 1-1. As a result, it was 60%.

  As can be seen from the above Example 2 and Example 1-1, the planarization rate could be increased as the polymerization degree of the resin was lowered.

[Example 3] (Low polymerization degree, glass electrode substrate, carbodiimide crosslinking)
<Fabrication of first substrate>
A first substrate 10 was produced in the same manner as in Example 1-1 except that the used crosslinking agent was different.

  First, a resin solution was prepared in the same manner as in Example 1-1, and 2 g of carbodiimide resin (“Carbodilite V-02 (trade name / product number)” manufactured by Nisshinbo Co., Ltd.) as a crosslinking agent was mixed with this resin solution. .

  A base material 11 made of glass on which a first electrode 12 similar to that of Example 1-1 was prepared, and the prepared resin solution was applied with a silicon rubber spatula (thickness 5 mm). It formed (refer FIG. 3 (A)). This was put into an oven, dried by heating at 100 ° C. for 10 minutes, and temporarily cured.

  After that, the upper surface of the first electrode 12 was exposed in the same manner as in Example 1-1 (see FIG. 3B).

  This was put in an oven and heated at 150 ° C. for 30 minutes to cure the coating layer 13. After that, the surface was lightly wiped with a sponge in running water, and the resin residue on the first electrode 12 was washed away. Thereby, the first substrate 10 shown in FIG. 1 was obtained. The level difference of the obtained first substrate 10 was measured with a contact-type level meter, and the flattening rate was determined in the same manner as in Example 1-1. As a result, it was 90%.

  As can be seen from the above Example 3 and Example 1-1, the flattening rate was substantially the same even if the crosslinking agent was different if the polymerization degree of the resin was the same.

[Example 4] (High polymerization degree + talc) with filler <Preparation of first substrate>
A first substrate 10 was produced in the same manner as in Example 1-1 except that the coating layer 13 was made of a resin having a high degree of polymerization and that the coating layer 13 contained a filler.

  First, polyvinyl alcohol partially saponified to 87 mol% (“GOHSENOL GH-23 (trade name, product number)” manufactured by Nippon Synthetic Chemical Industry Co., Ltd .; average polymerization degree 2300) · 1 g was dissolved in 20 g of distilled water, and used for a fountain pen. A few drops of red aqueous ink (Pilot) were added to prepare a resin solution. When the viscosity of this resin solution was measured with a rotational viscometer, it was 71 mPa · s (rotation speed: 10 rpm, 25 ° C.).

  To this resin solution, 2 g of silica (“Nipgel • AZ-200 (trade name / product number)” manufactured by Nippon Silica Kogyo Co., Ltd.) was added as a filler and dispersed with a homogenizer. After degassing under reduced pressure, the viscosity of the resin solution was measured with a rotational viscometer and found to be 640 mPa · s (rotation speed: 0.5 rpm, 25 ° C.).

  A base material 11 made of glass on which the same first electrode 12 as in Example 1-1 was prepared, and the prepared resin solution was applied with a silicon rubber spatula (thickness 5 mm), and the coating layer 13 was applied. It formed (refer FIG. 3 (A)). This was put into an oven, heat-dried at 100 ° C. for 5 minutes, and temporarily cured.

  After that, the upper surface of the first electrode 12 was exposed in the same manner as in Example 1-1 (see FIG. 3B).

  Subsequently, N-β (aminoethyl) -γ-aminopropyltrimethoxysilane (“KBE-603 (product number)” manufactured by Shin-Etsu Chemical Co., Ltd.) / Distilled water = 1/1 (weight ratio) as a silane coupling agent The liquid was sprayed on the surface of the substrate 11 with a sprayer. This was put in an oven and heated at 100 ° C. for 30 minutes to cure the coating layer 13. After that, the surface was lightly wiped with a sponge in running water, and the resin residue on the first electrode 12 was washed away. Thereby, the first substrate 10 shown in FIG. 1 was obtained. The level difference of the obtained first substrate 10 was measured with a contact-type level meter, and the flattening rate was determined in the same manner as in Example 1-1. As a result, it was 73%.

  As can be seen from Example 4 and Example 1-1 above, even when the degree of polymerization of the resin was increased, the planarization rate could be increased by including the filler.

[Example 5] (Medium polymerization degree, glass epoxy substrate)
<Fabrication of first substrate>
Except that the coating layer 13 was made of a resin having a moderate polymerization degree and a slightly higher degree of polymerization than that of Example 1-1, and that the base material 11 made of glass epoxy resin was used, Example 1- In the same manner as in Example 1, a first substrate 10 was produced.

  First, polyvinyl alcohol partially saponified to 80 mol% (“GOHSENOL KH-20 (trade name, product number)” manufactured by Nippon Synthetic Chemical Industry Co., Ltd .; average polymerization degree 2,000) 4 g was dissolved in 20 g of distilled water, and a fountain pen A few drops of red aqueous ink (manufactured by Pilot) was added to prepare a resin solution. When the viscosity of this resin solution was measured with a rotational viscometer, it was 23,000 mPa · s (rotation speed: 0.5 rpm, 25 ° C.).

  Moreover, the 70 mm x 90 mm base material 11 which consists of the glass epoxy resin in which the 1st electrode 12 which consists of silver was formed was prepared. The prepared resin solution was applied to the base 11 with a silicon rubber spatula (thickness 5 mm) to form a coating layer 13 (see FIG. 3A). This was put into an oven, heat-dried at 100 ° C. for 5 minutes, and temporarily cured.

  After that, a slide glass is wound with gauze (“Bencot (trade name)” manufactured by Asahi Kasei Co., Ltd.) and impregnated with a mixed solution of methanol / water = 3/1. 11 was wiped to expose the upper surface of the first electrode 12 (see FIG. 3B). The surface was observed with a microscope with a magnification of 50 times, and the red color of the colored polyvinyl alcohol aqueous solution disappeared from the upper surface of the first electrode 12 to confirm the exposure of the first electrode 12.

  Subsequently, the coating layer 13 was cured in the same manner as in Example 1-1 to obtain the first substrate 10 shown in FIG.

<Preparation of empty cell>
After the obtained first substrate 10 is thoroughly dried, a three-layer adhesive film (55 μm thick, Aichi Plastic) punched into the outer peripheral portion 11A of the first substrate 10 as the sealing member 40 in an outer shape of 70 mm × 90 mm and a width of 5 mm. (Made by Susu). Moreover, the 2nd board | substrate 20 with which the 2nd electrode 22 which consists of ITO was formed in the base material 21 which consists of glass with an external shape of 90 mm x 90 mm was prepared. The second substrate 20 is placed on the first substrate 10 on which the sealing member 40 is disposed so that the first electrode 12 and the second electrode 22 are orthogonal to each other, and 140 ° C., 0.2 MPa, 5 seconds. Heat press was performed under the conditions of

<Gelification test>
Subsequently, an electrolyte solution similar to that of Example 1-4 was prepared, and this electrolyte solution was injected by pressure from one hole of the first substrate 10 until the electrolyte overflowed from the other hole. It was. After that, the electrolyte solution over the hole was wiped off with a cloth soaked with ethanol, and the hole was temporarily sealed with cello tape to produce a display cell for gelation test. This display cell for gelation test was placed in an oven and heated at 100 ° C. for 10 minutes. Thereby, the electrolyte solution was gelled, and the display layer 30 including the electrolyte and the precipitation-dissolved material was formed.

[Comparative Example 5]
<Gelification test>
An empty cell was produced in the same manner as in Example 5 by using the same first substrate as used in Example 5 except that the coating layer was not formed. About this empty cell, the electrolyte solution was inject | poured similarly to Example 5, and it sealed temporarily, and produced the display cell for a gelation test. The obtained display cell for gelation test was placed in an oven and heated at 100 ° C. for 10 minutes, but gelation of the electrolyte did not occur. When heating was further continued for 10 minutes, gelation did not occur at all, and the electrolyte solution partially changed from yellow to orange. When allowed to stand overnight at room temperature, a part of the sealing member at the periphery of the cell was peeled off from the first substrate, and the electrolyte was oozing out. When the cell was disassembled, the electrolyte solution was impregnated into a substrate made of glass epoxy resin and swelled, and a part of the first electrode was peeled off from the substrate.

  As can be seen from Example 5 and Comparative Example 5 described above, the display layer 30 was successfully gelled by providing the coating layer 13.

[Example 6] (Low polymerization degree, film substrate, pending test)
A first substrate 10 was produced in the same manner as in Example 1-1, except that a flexible film-like substrate 11 was used.

  First, a resin solution was prepared in the same manner as in Example 1-1.

  Moreover, the base material 11 in which the 1st electrode 12 was formed was prepared. At that time, a transparent plastic ("ZEONOR (registered trademark)" manufactured by Nippon Zeon Co., Ltd.) is used as the base material 11, and the first electrode 12 is formed by depositing nickel (Ni) on the base material 11 by sputtering, and then plating. Copper (Cu) was deposited by the method, patterned into a predetermined shape, and nickel (Ni), gold (Au), and silver (Ag) were formed in order from the top. The width of the first electrode 12 was 125 μm, the interval was 125 μm, and the height was 30 μm.

  Subsequently, the prepared resin solution was applied to the base material 11 on which the first electrode 12 was formed with a silicon rubber spatula (thickness 5 mm) to form a coating layer 13 (see FIG. 3A). . This was put into an oven, heat-dried at 100 ° C. for 5 minutes, and temporarily cured.

  After that, the upper surface of the first electrode 12 was exposed in the same manner as in Example 1-1 (see FIG. 3B).

  Subsequently, a γ-aminopropyltriethoxysilane (“KBE-903 (product number)” manufactured by Shin-Etsu Chemical Co., Ltd.)) / Distilled water = 5/1 (weight ratio) mixed solution as a silane coupling agent on the surface of the substrate 11 Sprayed with a nebulizer. This was put in an oven and heated at 100 ° C. for 30 minutes to cure the coating layer 13. After that, the surface was lightly wiped with a sponge in running water, and the resin residue on the first electrode 12 was washed away. Thereby, the first substrate 10 shown in FIG. 1 was obtained. The level difference of the obtained first substrate 10 was measured with a contact-type level meter, and the flattening rate was determined in the same manner as in Example 1-1. As a result, it was 65%.

<Side etching test>
A three-layer adhesive film (100 μm thickness, manufactured by Aichi Plastics Co., Ltd.) punched out in an outer shape of 16 mm × 43 mm and a width of 3 mm was stacked as the sealing member 40 on the peripheral edge portion 11A of the first substrate 10. On top of this, a second substrate 20 (“ZEONOR (registered trademark)” manufactured by Nippon Zeon Co., Ltd.) in which a second electrode 22 made of ITO is formed on a base material 21 made of a transparent plastic of 23 mm × 38 mm is connected to the first electrode 12. It mounted so that the 2nd electrode 22 might be orthogonally crossed, and it heat-pressed on the conditions of 140 degreeC, 0.2 Mpa, and 5 second.

  Subsequently, an electrolyte solution similar to that of Example 1-4 was prepared, and this electrolyte solution was injected by pressure from one hole of the first substrate 10 until the electrolyte overflowed from the other hole. It was. After that, the electrolyte solution over the hole was wiped off with a cloth soaked with ethanol, and the hole was temporarily sealed with cello tape. This was placed in an oven and heated at 100 ° C. for 10 minutes. As a result, the electrolyte solution gelled, and the display layer 30 including the electrolyte and the precipitation-dissolved material was formed. After peeling off the temporary sealing cello tape, the sealing film 14 was overlaid on the entire surface of the first substrate 10 and bonded by heat pressing under conditions of 140 ° C., 0.2 MPa, 4 seconds, as shown in FIG. A display device was obtained.

  About the obtained display apparatus, the electrode wiring for a drive was performed and the 10,000-cycle repeated response was performed like Example 1-4. After that, when the display device is disassembled and the first substrate 10 is visually observed, side etching of the first electrode 12 or first electrolyte 12 permeates between the first substrate 12 and the base material 11. No peeling of one electrode 12 occurred.

<Pending test>
About the obtained 1st board | substrate 10, long side mountain bending, long side valley bending, short side mountain bending, and short side valley bending are made into 1 cycle, 20 mm of long side directions, 10 mm of short side directions, and a bending speed 1 time / 2 seconds. Bending was performed, and peeling of the first electrode 12 was observed every 250 cycles. After repeating 1,000 cycles of bending, the first electrode 12 was observed, and there was no peeling of the first electrode 12.

[Comparative Example 6]
<Pending test>
A display device was produced in the same manner as in Example 6 by using the same base material on which the first electrode as used in Example 6 was formed without forming a coating layer. The obtained display device was subjected to a pending test in the same manner as in Example 6. As a result, peeling of the first electrode occurred after 500 cycles of bending.

  As can be seen from Example 6 and Comparative Example 6 above, when a film-like substrate is used, the first electrode is firmly fixed to the substrate by providing a coating layer, and side etching and peeling are suppressed. I was able to.

  The present invention has been described with reference to the embodiments and examples. However, the present invention is not limited to the above embodiments and examples, and various modifications can be made. For example, in the embodiments and examples described above, the case where the coating layer 13 is formed on the entire surface of the base material 11 has been described. However, the coating layer 13 is not necessarily formed on the entire surface, and hatched lines in FIG. What is necessary is just to form so that at least the 1st electrode 12 may be covered as shown as the area | region which did. That is, the coating layer 13 is not necessarily provided on the peripheral edge portion 11 </ b> A of the base material 11.

  In this case, after masking a portion where formation of the coating layer 13 is not desired, for example, the peripheral portion 11A of the substrate 11 with a protective film, water-repellent paint, or grease, the coating layer 13 is applied to the entire surface of the substrate 11. Then, it is possible to temporarily cure and peel off the covering layer 13 of the peripheral portion 11A together with the mask.

  When the coating layer 13 is not provided on the peripheral edge portion 11 </ b> A of the base material 11, an appropriate process for improving the adhesiveness of the sealing member 40 may be performed on the peripheral edge portion 11 </ b> A of the base material 11.

  Further, for example, in the second substrate 20 in the above embodiment, the covering layer 13 may be formed in the interelectrode region between the second electrodes 22 made of ITO.

  Further, for example, in the embodiment and the example described above, the case where the display layer 30 includes a so-called gel electrolyte and a precipitated dissolved material has been described. However, the display layer 30 includes a solvent and a precipitated dissolved material. It may be in a liquid state.

  Furthermore, for example, the material and thickness of each layer described in the above embodiment and the above examples, or the film formation method and film formation conditions are not limited, and other materials and thicknesses may be used. A film forming method and film forming conditions may be used.

  In addition, in the above embodiment, the simple matrix display device in which the first electrode 12 and the second electrode 22 are formed in a plurality of stripes orthogonal to each other has been described. The present invention can also be applied to an active matrix type in which the second electrodes 22 are formed as a common electrode.

  Furthermore, in the above-described embodiment, the configurations of the substrate and the display device are specifically described. However, it is not necessary to provide all layers, and other layers may be further provided.

  The board | substrate and its manufacturing method by this invention are applicable also to what kind of board | substrate, as long as it has the unevenness | corrugation by the electrode and base material which should expose an upper surface.

  In the above embodiment, the case where the present invention is applied to an electrodeposition type display device has been described. The same excellent effect can be obtained.

It is a disassembled perspective view showing the structure of the display apparatus which has a board | substrate which concerns on the 1st Embodiment of this invention. It is sectional drawing along the II-II line of the display apparatus shown in FIG. FIG. 4 is a cross-sectional view illustrating a method of manufacturing the display device illustrated in FIG. 1 in order of steps. It is a top view showing the modification of the display apparatus shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... 1st board | substrate, 11 ... Base material, 11A ... Peripheral part, 11B ... Interelectrode area | region, 12 ... 1st electrode, 13 ... Coating layer, 14 ... Sealing film, 20 ... 2nd board | substrate, 21 ... Base material, 22 ... 2nd electrode, 23A, 23B ... Injection hole, 30 ... Display layer, 40 ... Sealing member

Claims (27)

A substrate on which a plurality of electrodes are formed;
And a coating layer made of a resin formed in a region between the plurality of electrodes. The substrate according to claim 1, wherein the coating layer is made of a water-soluble resin. The substrate according to claim 2, wherein the coating layer is made of a resin containing polyvinyl alcohol. The substrate according to claim 2, wherein the coating layer is made of a resin including an aqueous acrylic resin or an amino resin. The substrate according to claim 1, wherein the coating layer is formed so as to cover side surfaces of the plurality of electrodes. The substrate according to claim 1, wherein the covering layer is formed so as to cover an entire region between the plurality of electrodes. The substrate according to claim 1, wherein the coating layer is further formed on a peripheral portion of the base material. The substrate according to claim 1, wherein the coating layer includes a filler. The substrate according to claim 1, wherein the coating layer includes at least one of a pigment and a dye. Forming a coating layer made of a resin so as to cover at least the plurality of electrodes on a substrate on which a plurality of electrodes are formed;
And a step of exposing the upper surfaces of the plurality of electrodes by cleaning and forming the coating layer in a region between the plurality of electrodes. The method for manufacturing a substrate according to claim 10, wherein the coating layer is made of a water-soluble resin. The method for manufacturing a substrate according to claim 11, wherein the coating layer is made of a resin containing polyvinyl alcohol. The method for manufacturing a substrate according to claim 11, wherein the coating layer is made of a resin containing an aqueous acrylic resin or an amino resin. The method for manufacturing a substrate according to claim 10, further comprising a step of curing the coating layer by crosslinking with a crosslinking agent after the step of forming the coating layer in a region between the plurality of electrodes. The method for producing a substrate according to claim 14, wherein the coating layer is crosslinked by impregnating with a crosslinking agent. The method for producing a substrate according to claim 14, wherein a crosslinking agent that dissolves in water or a water-soluble organic solvent is used as the crosslinking agent. The method for producing a substrate according to claim 16, wherein a silane coupling agent that dissolves in water or a water-soluble organic solvent is used as the crosslinking agent. The method for producing a substrate according to claim 16, wherein a silane coupling agent having an amine group or an amide group as a functional group is used as the crosslinking agent. A display device having a display layer between a first substrate and a second substrate,
At least one of the first substrate and the second substrate is
A substrate on which a plurality of electrodes are formed;
A display device comprising: a coating layer made of a resin formed in a region between the plurality of electrodes. The display device according to claim 19, wherein the coating layer is made of a water-soluble resin. The display device according to claim 20, wherein the coating layer is made of a resin containing polyvinyl alcohol. The display device according to claim 20, wherein the coating layer is made of a resin including an aqueous acrylic resin or an amino resin. The display device according to claim 19, wherein the covering layer is formed so as to cover side surfaces of the plurality of electrodes. The display device according to claim 19, wherein the covering layer is formed so as to cover an entire region between the plurality of electrodes. The display device according to claim 19, wherein the coating layer is further formed on a peripheral portion of the base material. The display device according to claim 19, wherein the coating layer includes a silane coupling agent having an amine group or an amide group as a functional group. The display device according to claim 19, wherein the display layer includes a precipitation-dissolving material that is precipitated and dissolved by an oxidation-reduction reaction.

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