JP2012063690A - Method for manufacturing electrophoretic display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an electrophoretic display device with a high contrast in which an electrophoretic ink can be uniformly supplied without mixing of air bubbles, a gap between electrode substrates can be controlled to be uniform, intrusion of particles into an adhesive is suppressed, and breakage due to peeling of the substrates from each other can be prevented.SOLUTION: The method for manufacturing an electrophoretic display device 30 includes steps of: forming a plurality of cells 15 comprising insulating structures 16 on a first electrode substrate 10; filling the cells 15 with an electrophoretic ink precursor A containing at least one kind of electrophoretic particles and a solvent; removing the solvent from the electrophoretic ink precursor A; filling the cells 15 with an electrophoretic ink precursor B containing no particles; laminating the first electrode substrate 10 with a second electrode substrate 20; and dispersing the electrophoretic particles in the electrophoretic ink precursor A from which the solvent is removed, into the electrophoretic ink precursor B.

Description

  The present invention relates to a method for manufacturing an electrophoretic display device capable of reversibly changing a visual state by the action of an electric field or the like.

  In general, an electrophoretic display device is a display medium that can obtain a desired display by controlling the direction of an electric field, is low in cost, has a wide viewing angle as a printed matter, has low power consumption, and has a display memory property. Has attracted attention in recent years because of its advantages.

  However, since the electrophoretic particles in the electrophoretic ink used in the electrophoretic display device are repeatedly displayed for a long period of time, the particles aggregate together or the particles are unevenly distributed in the display area. There has been proposed a method for suppressing aggregation and uneven distribution of particles by filling electrophoretic ink into a large number of finely isolated cells (small sections). Many manufacturing methods have been proposed for uniformly filling electrophoretic ink in such a large number of cells and sealing between two opposing electrode substrates.

For example, 1) In order to provide a method for manufacturing an electrophoretic display device capable of simplifying the manufacturing process and uniformly filling the electrophoretic ink, at least one of the electrodes having light transmissivity is formed so that light can be transmitted. A substrate, a substrate on which an electrode opposed to the electrode is formed, an electrophoretic ink containing at least one kind of electrophoretic particles, and a seal portion that seals the electrophoretic ink between the substrates arranged opposite to each other A method for producing an electrophoretic display device comprising: applying an electrophoretic ink precursor A containing at least one or more types of electrophoretic particles to one substrate; and electrophoretic ink precursor B on the other substrate. And a step of forming an electrophoretic ink by combining the electrophoretic ink precursor A and the electrophoretic ink precursor B. 2. Method of manufacturing electrophoretic display device (for example, refer to Patent Document 1) 2) A pair of substrates in which a first electrode and a second electrode capable of applying a voltage different from the first electrode are formed on at least one substrate In a method for manufacturing an electrophoretic display device, in which an electrophoretic dispersion containing charged electrophoretic particles is filled, an alternating voltage is applied to the first electrode and the second electrode in the electrophoretic dispersion containing charged electrophoretic particles. To induce an electrophoretic phenomenon, move the charged electrophoretic particles onto the first electrode or the second electrode, and coat the electrode surface on the substrate; A step of filling a dispersion liquid for migration onto a substrate on which a first electrode and a second electrode are formed; and a pair of substrates on which the first electrode and the second electrode are formed on the at least one substrate. And a step of sealing between (3) A plurality of spaces partitioned by a partition are formed between a pair of substrates, and the space is filled with a liquid containing charged particles. In the method of manufacturing an electrophoretic display device, a liquid that is commonly present in all spaces is applied by a coating device, and liquids having different components are discharged from a plurality of spaces by a discharging device and filled in each space. As a specific embodiment of the method for producing an electrophoretic display device, a low-boiling point solution in which charged particles are dispersed and a liquid containing a high-boiling point solution are applied by an inkjet device, and a necessary amount of solution (low-boiling point solution) After drying, the liquid in which the dye is dissolved is ejected by an ink jet device and filled in each space, so that a plurality of colored inks are applied to the desired place using the ink jet. Method of manufacturing an electrophoretic display device capable of preventing clogging of the nozzles (e.g., see Patent Document 3) it has been proposed by dividing.

However, in the method of manufacturing each electrophoretic display device described in Patent Documents 1 and 2, the electrode substrate interval (gap) is disturbed due to particles being sandwiched between the structure 16 constituting the cell and the electrode substrate. Display deterioration due to adhesion of electrophoretic ink or electrophoretic particles into the adhesive when the two electrode substrates are bonded to each other, damage to the display device due to poor adhesion, or filling of the electrophoretic ink to paste the electrode At present, it is not possible to sufficiently solve the problem of display defects due to mixing of bubbles at the time of matching.
In addition, in the method for manufacturing each electrophoretic display device described in Patent Document 3, first, a liquid that exists in common in all spaces is filled, and then liquids having different components are filled in each of the plurality of spaces. . When the amount of liquids with different components is larger than the space, they mix by flowing out to other spaces, and when the amount of liquids with different components is smaller than the space, there is no mixing between the liquids, but bubbles There are issues such as being left behind.

On the other hand, insulating particles are dispersed in a liquid phase dispersion medium as a method for producing a display body that prevents contamination of the production environment and production equipment due to scattering of particles and enables easy and reliable adjustment of the amount of particles. And manufacturing the display panel through a step of forming a dispersion, a step of supplying the dispersion into the space using an inkjet method, and a step of volatilizing the liquid dispersion medium from the space ( For example, refer to Patent Document 4) or a dispersion liquid in which at least two types of image display media are dispersed in a dispersion medium is disposed at a predetermined position on the substrate through a mask, and after the dispersion medium is removed by drying, the substrates are stacked. An image display panel manufacturing method (for example, see Patent Document 5) characterized by combining them has been proposed.
However, the panel disclosed in Patent Documents 4 and 5 is a display medium in which powder is enclosed between electrode substrates, and is basically a technique that is different from an electrophoretic display device using an electrophoretic ink that dislikes mixing of bubbles. The idea is different.

JP 2007-33680 A (Claims, Examples, etc.) Japanese Patent No. 3531916 (Claims, Examples, etc.) JP 2002-202533 A (Claims, Examples, etc.) JP 2003-167275 A (Claims, Examples, etc.) JP 2006-58564 A (Claims, Examples, etc.)

  The present invention has been made in view of the above-mentioned problems of the prior art and the current situation, and is intended to solve this problem. The electrophoretic ink can be uniformly filled without introducing bubbles, and the electrode substrate interval can be controlled uniformly. An object of the present invention is to provide a method for manufacturing a high-contrast electrophoretic display device capable of preventing damage caused by peeling of substrates by suppressing particle mixing into an adhesive.

  As a result of intensive studies to solve the above-described conventional problems, the present inventor has formed a step of forming a plurality of cells made of an insulating structure on the first electrode substrate, and at least one kind of electrophoresis Filling the cell with the electrophoretic ink precursor A containing particles and a solvent, removing the solvent from the electrophoretic ink precursor A, and filling the cell with the electrophoretic ink precursor B containing no particles. A step of bonding the first electrode substrate and the second electrode substrate, and a step of dispersing the electrophoretic particles in the electrophoretic ink precursor A from which the solvent has been removed, in the electrophoretic ink precursor B. Thus, the inventors have found that a method for manufacturing an electrophoretic display device having the above-described object can be obtained, and have completed the present invention.

That is, the present invention belongs to the following (1) to (6).
(1) The step of forming a plurality of cells made of an insulating structure on the first electrode substrate, and the electrophoretic ink precursor A containing at least one kind of electrophoretic particles and a solvent are filled in the cells. A step of removing the solvent from the electrophoretic ink precursor A, a step of filling the cell with the electrophoretic ink precursor B not containing particles, and bonding the first electrode substrate and the second electrode substrate together. A method for producing an electrophoretic display device, comprising: a step; and a step of dispersing electrophoretic particles in the electrophoretic ink precursor A from which the solvent has been removed, into the electrophoretic ink precursor B.
(2) The electrophoretic display according to (1), wherein the step of dispersing the electrophoretic particles in the electrophoretic ink precursor A from which the solvent has been removed in the electrophoretic ink precursor B uses ultrasonic waves. Device manufacturing method.
(3) The electrophoretic display according to (1), wherein the step of dispersing the electrophoretic particles in the electrophoretic ink precursor A from which the solvent has been removed is used in the electrophoretic ink precursor B. Device manufacturing method.
(4) The step of dispersing the electrophoretic particles in the electrophoretic ink precursor A from which the solvent is removed to the electrophoretic ink precursor B alternately applies a voltage between the electrodes of the electrophoretic display device. The method for manufacturing an electrophoretic display device according to (1).
(5) The method for manufacturing an electrophoretic display device according to (1), wherein at least two of the methods (2), (3), and (4) are combined.
(6) The method for manufacturing an electrophoretic display device according to any one of (1) to (5), including a step of removing electrophoretic particles present on the upper surface of the structure.

According to the present invention, the electrophoretic ink can be filled uniformly without mixing air bubbles, the electrode substrate spacing can be controlled uniformly, and particle contamination into the adhesive can be suppressed and damage caused by peeling between the substrates can be prevented. By performing the step of dispersing the electrophoretic particles in the electrophoretic ink precursor A to the electrophoretic ink precursor B, a method for manufacturing a high-contrast electrophoretic display device is provided.

(A) is the schematic which shows the state with which the electrophoretic ink precursor A is filled only into the inside of a cell. (B) is the schematic which shows the state which removed the solvent from the electrophoretic ink precursor A. FIG. (C) is the outline which shows the state which formed the seal part. (A) is the schematic which shows the state with which the electrophoretic ink precursor B was filled into the cell. (B) is the schematic which shows the state which bonded electrode substrates together. (C) is the schematic which shows an example of the electrophoretic display device manufactured by the method of this invention. (A) is the schematic which shows the state with which the electrophoretic ink precursor A is filled only into the inside of a cell. (B) is the schematic which shows the state which removed the solvent from the electrophoretic ink precursor A. FIG. (C) is the outline which shows the state which removed the electrophoretic particle which exists on a structure. (D) is the schematic which shows the state in which the seal part was formed. (A) is the schematic which shows the state with which the electrophoretic ink precursor B was filled into the cell. (B) is a schematic drawing which shows the state which bonded electrode substrates together. (C) is a schematic drawing which shows an example of the electrophoretic display device manufactured by the method of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 to 4 are schematic drawings showing manufacturing steps as an example of a method for manufacturing an electrophoretic display device of the present invention.
As shown in FIG. 1A, the manufacturing method of the present embodiment (hereinafter referred to as “the method of the present invention”) is composed of insulating structures 16, 16... Serving as partitions on the first electrode substrate 10. A plurality of cells 15, 15..., A step of filling the cells 15, 15... With an electrophoretic ink precursor A containing at least one kind of electrophoretic particles and a solvent, and FIG. b) removing the solvent from the electrophoretic ink precursor A, and as shown in FIGS. 1 (c) and 2 (a), the electrophoretic ink precursor B containing no particles is added to the electrophoretic ink precursor B. The step of filling the cells 15, 15, the step of bonding the first electrode substrate 10 and the second electrode substrate 20, and the electrophoretic ink precursor A from which the solvent has been removed, as shown in FIG. Of dispersing electrophoretic particles in electrophoretic ink precursor B By having, it becomes the electrophoretic display device 30 shown in FIG. 2 (c) is produced.
Further, when the electrophoretic particles 16a are present on the upper surface of the structure 16 as shown in FIG. 3B, a step of removing the electrophoretic particles 16a as shown in FIG. 3C can be included.

In the method of the present invention, at least one of the first electrode substrate 10 and the second electrode substrate 20 used for functioning as an electrophoretic display device has a light transmissive base on which an electrode having light transparency is formed. What is necessary is just to be comprised from the material. On the surface of the electrode substrate 10 on which the electrodes are formed, a plurality of cells 15, 15... Composed of insulating structures 16, 16.
As the electrode substrate 10, for example, a transparent resin film or transparent glass formed by applying a transparent conductive material such as ITO by an evaporation method such as a coating method, an ion plating method, a sputtering method, or a resin A non-conductive material surface such as a film, a resin plate, glass, ceramics, or the like formed with a conductive material film (layer) such as metal, or a metal plate can be used.
These substrates can be formed by patterning by a conventionally used method such as photoetching, or a TFT (Thin Film Transistor) substrate used for liquid crystal or the like can be used. Although possible, it is not limited to these.

As a method of forming a plurality of cells 15, 15... Composed of insulating structures 16, 16... Serving as partition walls on these electrode substrates 10, for example, on the surface of the electrode substrate 10 on which electrodes are formed. A thermoplastic or thermosetting precursor material using a male mold pre-patterned after coating a layer of a thermoplastic or thermosetting precursor material or resin material that constitutes an insulating structure Alternatively, a method of embossing and curing a layer of a resin material, or coating a layer of a photocurable precursor material on the surface of the substrate on which the electrode is formed, and then exposing the photocurable layer to an image, For example, a method of removing a non-exposed area with a developer or a solvent may be used.
Examples of the precursor material include acrylic, epoxy, olefin, paraffin, vinyl acetate, urethane, ionomer, elastomer, silicone, and fluorine monomers such as acrylate, methacrylate, and cyanoacrylate. At least one of oligomers and polymers can be used.
These are selected so as to obtain desirable chemical, physical, mechanical properties, insulation properties, such as strength, flexibility, flexibility, etc., and can be used in combination of two or more types. Depending on the body material, additives can be added as appropriate.

  Also, after forming holes such as squares, rectangles, regular hexagons, circles, triangles, etc. by laser processing, for example, high-frequency short pulse method, the resin film is adhered to the surface of the electrode substrate 10 on which the electrodes are formed. In which a plurality of cells 15, 15... Composed of insulating structures 16, 16... Are formed, or hollow tubes are bundled, side surfaces are bonded and sliced with respect to the opening surface, and then the substrate electrode is formed. On the surface on which the electrodes of the substrate are formed after slicing the material of the porous body. A method of forming a plurality of cells 15, 15... Composed of insulating structures 16, 16.

  Furthermore, by using a screen printing method, a relief printing method or an intaglio (gravure) printing method, a thermoplastic, thermosetting or photocurable precursor material or the like is formed on the surface of the electrode substrate 10 on which the electrodes are formed. A method of forming a plurality of cells 15, 15... Composed of insulating structures 16, 16... By printing, or a fabric obtained by weaving thermoplastic or thermosetting fibers is used for the electrode substrate 10. The method etc. which adhere | attach on the surface in which the electrode was formed are also mentioned. In particular, in the intaglio (gravure) printing method, after filling the gravure plate with a resin, an electrode or a cover film is arranged and pattern transfer is performed, and the structure 16 is produced by mold release and curing treatment, In this method, an electrode or a cover film is placed, cured and transferred as it is, and the cured film and the gravure plate are separated to produce a plurality of cells 15, 15... Composed of insulating structures 16, 16. It is done.

Further, a plurality of cells 15, 15... Composed of insulating structures 16, 16... May be formed by a photo etching method or a laminate coating method.
In the photoetching method, for example, a UV curable resin is applied to the surface of the electrode substrate 10 on which the electrodes are formed, and then a wall is formed in accordance with the shape of the plurality of cells 15, 15. It can be formed by covering a mask having a pattern so that only the portion of the structure 16 to be exposed is irradiated with UV light, irradiating the entire surface with UV light to cure the UV curable resin, and removing the non-cured portion. it can.
In the laminate coating method, for example, a mesh sheet having an adhesive layer formed in a pattern of a plurality of cells 15, 15... Made of insulating structures 16, 16. It can be formed by thermocompression bonding or the like.
As a method of forming a plurality of cells 15, 15... Composed of preferable insulating structures 16, 16..., Embossing, various printing methods [screen printing, letterpress, Printing method, intaglio (gravure) printing], laser processing method and photo etching method are desirable.

  In the method of the present invention, the opening area, height, opening shape and the like formed between the plurality of cells 15, 15... Composed of the insulating structures 16, 16. It is appropriately defined depending on the shape of the display device and the like. In the present embodiment, the height of the plurality of cells 15, 15... Composed of the insulating structures 16, 16... Is set lower than a seal portion 26 described later.

In the method of the present invention, as shown in FIG. 1 (a), at least one kind of electrophoretic particles is formed on the electrode substrate 10 on which a plurality of cells 15, 15 ... made of insulating structures 16, 16 ... are formed. The cells 15, 15,... Are filled with an electrophoretic ink precursor A containing a solvent and a solvent.
As a method of filling the electrophoretic ink precursor A, for example, a method of filling using an ink jet, a method of casting the electrophoretic ink precursor A and leveling the surface with a doctor blade, silk printing, gravure, etc. Examples thereof include printing, dripping with a dispenser, and application with a die coater.
In the method of the present invention, as will be described later, the electrophoretic ink C to be accommodated in the manufactured electrophoretic display device 30 (between the electrode substrates 10 and 20) is at least one kind of fine particles, It contains a solvent and is constituted by dispersing the electrophoretic particles in the electrophoretic ink precursor A from which the solvent has been removed to the electrophoretic ink precursor B that does not contain electrophoretic particles. Here, the electrophoretic ink precursor A and the electrophoretic ink precursor B are appropriately determined according to the display properties of the electrophoretic ink C.
In addition, when manufactured, a multi-color, full-color electrophoretic display device is obtained, as in the case where a plurality of types (colors) of electrophoretic ink are arranged so as to display a certain pattern. In this case, the electrode substrate 10 is addressed and filled with various color inks by ink jet, or the unfilled portion is masked with a photomask or the like and only the unmasked portion is filled. In addition, a method of obtaining a multi-color, full-color electrophoretic display device by repeatedly removing the mask, masking an unfilled portion with a photomask, and filling only the unmasked portion, etc. However, it is not limited to the method described above.

In the method of the present invention, as shown in FIG. 1A, the electrophoretic ink precursor A filled in the cells 15, 15... Of the electrode substrate 10 includes at least one type of electrophoretic particles and a solvent. If there is, it is good.
As the electrophoretic particles that can be used, for example, colored or colorless (white) inorganic pigment particles, organic pigment particles, polymer fine particles, and the like can be used, and these can be used alone (one type) or two or more types. It can be used by mixing. Moreover, the fine particle by which the lipophilic surface treatment was carried out may be sufficient. Preferably, those having an average particle diameter of 0.05 to 20 μm are used, and those having an average particle diameter of 0.1 to 10 μm are particularly preferable. The total content of these fine particles is preferably 5 to 95% by mass, more preferably 10 to 80% by mass with respect to the electrophoretic ink precursor A.
As the solvent, for example, hydrocarbon-based, aromatic-based, ester-based, ketone-based, terpene-based, alcohol-based, silicone-based, and fluorine-based solvents may be used alone or in combination of two or more. it can. Preferably, since the solvent is removed from the electrophoretic ink A in the next step, the solvent can be removed by a simple method, and a suitable electrophoretic ink C is obtained without adversely affecting the physical properties of the electrophoretic particles. In view of the above, it is particularly desirable to use at least one solvent selected from hydrocarbons and alcohols.
The content of these solvents is based on the total amount of the electrophoretic ink precursor A, taking into account the electrophoretic particles to be used, the solvent type, and the point of efficiently removing the solvent from the electrophoretic ink precursor A in the next step. It is preferable to contain so that it may become 20-85%, More preferably, it is desirable to set it as 35-65%.
Further, as the electrophoretic ink precursor A, one or more kinds of electrophoretic particles and a solvent may further contain a dispersant, a charge control agent, and the like. Examples of the dispersant that can be used include various commonly used dispersants, surfactants and polymer surfactants such as nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. Surfactant etc. are mentioned, However, It is not limited to these. The content of these dispersants is appropriately determined depending on the electrophoretic particles and solvent type to be used, but is preferably contained so as to be 0.01 to 50.0% with respect to the total amount of electrophoretic ink C. More preferably, the content is preferably 0.5 to 30%.
As the charge control agent, various types used for electrophoretic display can be used.

When the electrophoretic ink precursor A is filled, preferably, a wettability adjusting step for improving the wettability of the electrophoretic ink precursor A may be added to the surface of the electrode substrate 10. . The electrophoretic ink precursor A is sufficiently distributed to the inner walls and corners of the plurality of cells 15, 15... Made of the insulating structure 16, and a gas such as air is made of the insulating structures 16, 16. This is a preferable process for expelling the cells 15, 15.
As this wettability adjustment step, for example, solvent treatment, acid treatment, alkali treatment, ozone treatment, plasma treatment, corona discharge treatment, UV treatment, UV ittro treatment, laser treatment, treatment with electron beam, treatment by ion implantation method, Ion beam treatment, ion irradiation treatment, primer treatment, surfactant treatment, sputtering treatment, (physical vapor deposition), CVD (chemical vapor deposition), polymer layer formation and inorganic layer formation, etc. Is mentioned. These may be used in combination, and are not limited to these.
Further, in order to remove the contamination on the substrate surface in advance, the wettability can be adjusted more effectively by combining treatment such as washing with a solvent, for example, washing with alcohol.

Next, in the method of the present invention, as shown in FIG. 1B, the solvent is removed from the electrophoretic ink precursor A filled in the cells 15, 15... On the electrode substrate 10.
Examples of the method for removing the solvent from the charged electrophoretic ink precursor A include air drying (drying by applying air at room temperature), heat drying, hot air drying, and vacuum drying. Preferably, the ink is used. From the viewpoint of preventing the precursor A from being modified by heat, air drying is desirable.
In addition, 17 in FIG.1 (b) is a recessed part comprised from the electrophoretic particle after removing a solvent from the electrophoretic ink precursor A. FIG. A ′ represents the remainder (electrophoretic particles) obtained by removing the solvent from the electrophoretic ink precursor A.

In the method of the present invention, when the electrophoretic particles 16a are present on the upper surface of the structure 16, as shown in FIGS. 3B and 3C, the electrophoretic particles 16a existing on the upper surface of the structure 16, 16a ... can also be removed.
Examples of the method for removing the electrophoretic particles 16a, 16a ... existing on the upper surfaces of the cells 15, 15 ... include peeling using an adhesive tape, peeling using an adhesive roller, and removal using a scraper. From the point that peeling of the electrophoretic particles and removal of the peeled electrophoretic particles outside the display area can be performed in one step, peeling with an adhesive tape is desirable.
Electrodes due to the electrophoretic particles being sandwiched between the structure constituting the conventional cell and the electrode substrate by performing the step of removing the electrophoretic particles 16a, 16a ... existing on the upper surfaces of the cells 15, 15 ... It is possible to solve the problem of display deterioration due to the disturbance of the gap between the substrates (gap).

Next, in the method of the present invention, after removing the solvent from the electrophoretic ink precursor A, as shown in FIGS. 1C and 2A, the electrophoretic ink precursor B containing no electrophoretic particles is used. Are filled in the cells 15, 15.
The electrophoretic ink precursor B to be used may be any one that does not contain electrophoretic particles and contains at least one kind of solvent. For example, a liquid precursor containing a solvent, a dispersant, and a charge control agent. B is mentioned. Preferably, it is desirable that the electrophoretic ink precursor B is a single solvent or a mixture of at least two kinds of solvents from the viewpoint that adhesiveness decreases when a dispersant, charge control agent, or the like adheres to the seal portion.
Solvents that can be used include various commonly used dispersants, surfactants and polymer surfactants such as nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric systems. Surfactants, polymer surfactants and the like can be mentioned, but are not limited thereto. The content of these dispersants is appropriately determined depending on the electrophoretic particles and solvent type to be used, but is preferably contained so as to be 0.01 to 50.0% with respect to the total amount of electrophoretic ink C. More preferably, the content is preferably 0.5 to 30%.
Furthermore, as a solvent, the thing of the various types conventionally used for the electrophoretic display can be used, for example. Specifically, aliphatic hydrocarbons such as aromatic hydrocarbons, hexane, cyclohexane, kerosene, isopar, paraffin hydrocarbons, halogenated hydrocarbons, phosphate esters, phthalate esters, carboxylate esters , Chlorinated paraffin, N, N-dibutyl-2-butoxy-5-tertioctylaniline, and the like, but are not limited thereto. The content of these solvents is appropriately determined depending on the electrophoretic particles and the solvent to be used, but is preferably 25 to 95% with respect to the total amount of electrophoretic ink C, and more preferably 30%. It is desirable to set it to -90%. Further, various oil-soluble dyes can be dissolved and colored in the solvent.
As the charge control agent, various types used for electrophoretic display can be used.

  In the method of the present invention, as the method of filling the electrophoretic ink precursor B, a method of filling using an inkjet, a method of casting the electrophoretic ink precursor B and smoothing the surface with a doctor blade, etc. Examples thereof include a method of casting the electrophoretic ink precursor B and removing the excess electrophoretic ink precursor B by centrifugal force.

Further, when the electrode substrate 10 is filled with the electrophoretic ink precursor B, before the filling, in order to prevent bubbles such as air from entering or remaining in the display area surrounded by the seal portion 26 as much as possible. It is preferable that the gas dissolved in the electrophoretic ink precursor B, the entrained air, or the like be sufficiently degassed and removed at or after filling.
Through this deaeration process, air bubbles are prevented from entering between the substrates after they are bonded together (after sealing), so display irregularities, display defects, deterioration due to bubble growth, etc. are suppressed. Thus, an electrophoretic display device having stable display quality over a long period of time can be obtained.

Examples of the deaeration method before filling include, for example, a method of stirring the electrophoretic ink precursor B with a stirring rod, a method of heating, a method of stirring while warming, a method using ultrasonic waves, a method using reduced pressure, and a centrifugal method. Examples thereof include, but are not limited to, a method using force and a method using additives such as an antifoaming agent.
Further, examples of the degassing method at the time of filling the electrophoretic ink precursor B include a method of filling while heating, a method of filling under reduced pressure, and the like, but are not limited thereto.
On the other hand, as a degassing method after filling with the electrophoretic ink precursor B, a method of applying ultrasonic waves to the substrate after filling, a method of heating, a method of using centrifugal force, a method of keeping under reduced pressure, and leaving for a certain time. Examples include, but are not limited to, methods. Furthermore, these methods can be used in combination.

In this embodiment, first, as shown in FIG. 1C, the seal portion 26 on the electrode substrate 10 so as to be in contact with the structures 16 and 16 of the cells 15 and 15 which are the outermost peripheral portions in the display area. 26 is formed. As a method of forming the seal portions 26, 26, a thermoplastic, thermosetting or photo-curing precursor material or the like is used by various printing methods [screen printing method, letterpress printing method, intaglio printing (gravure) printing], by a dispenser. It can be formed by a coating method. The height of the seal portions 26, 26 when forming the seal portions 26, 26 is such that the electrophoretic ink C is prepared by filling the cells 15, 15,... With the electrophoretic ink precursor B that does not contain electrophoretic particles. Therefore, it is set higher by about 0.01 to 2 mm than the height of the plurality of cells 15, 15... Made of an insulating structure, and is 0.5 mm higher in this embodiment. Further, the seal portions 26 and 26 of the present embodiment are formed by dropping UV curable resin with a dispenser. After the seal portions 26, 26 were formed on the electrode substrate 10, as shown in FIG. 2A, the cells 15, 15,... Were filled with the electrophoretic ink precursor B that does not contain electrophoretic particles.
In the above embodiment, the electrophoretic ink precursor B is filled after the seal portions 26 and 26 are formed. However, the seal portions 26 and 26 may be formed after the electrophoretic ink precursor B is filled. is there.

As the second electrode substrate 20 used in the present invention, for example, a transparent conductive material such as ITO is formed on a transparent resin film or transparent glass by a coating method, an ion plating method, a vapor deposition method such as a sputtering method, or the like. A light transmissive material, a resin film, a resin plate, a nonconductive material such as glass, ceramics or the like on which a conductive material film (layer) such as a metal is formed, or a metal plate can be used.
The electrophoretic ink C is sealed between the electrode substrates 10 and 20 by bonding the electrode substrates 10 and 20 together.

  Also, as a method of bonding the first electrode substrate 10 and the second electrode substrate 20, a method of curing the seal material 26 after deforming the seal material 26 by applying a load on the electrode substrates 10 and 20, There is a method of aligning one end of the substrate 20 on the electrode substrate 10, aligning both substrates while sequentially deforming the sealing material with a roller, and then curing the sealing material 26. At this time, the method for curing the sealing material 26 needs to be appropriately selected depending on the material of the selected sealing material. In addition, by performing the bonding process in a vacuum, air bubbles may be prevented from being mixed into the display area surrounded by the seal portion 26.

In the method of the present invention, as shown in FIGS. 2B and 2C, the electrophoretic ink C is obtained by dispersing the electrophoretic particles in the electrophoretic ink precursor A in the electrophoretic ink precursor B. ing. As a method of dispersing the electrophoretic particles in the electrophoretic ink precursor A in the electrophoretic ink precursor B, ultrasonic vibration (frequency is 20 kHz or more) is applied, and the electrophoretic ink is left in a certain temperature or higher environment for a certain period of time. (Frequency is less than 20 kHz), repeated refresh operation (repetitively applying an alternating voltage equivalent to the drive voltage), repeatedly applying an alternating voltage higher than the drive voltage, repeatedly applying an alternating voltage lower than the drive voltage, etc. Is mentioned.
In this embodiment, the electrophoretic ink C was obtained by leaving the environment at 60 ° C. for 30 minutes and then repeating the refresh operation.
By performing the step of dispersing the electrophoretic particles in the electrophoretic ink precursor A into the electrophoretic ink precursor B, it is possible to solve the problem of contrast reduction due to aggregation of the electrophoretic particles.

  In the method of the present invention, as described above, as shown in FIG. 2 (a), the electrophoretic ink precursor B after the solvent removal in the cell 15 is filled with the electrophoretic ink precursor B, and then FIG. As shown in b), the second electrode substrate 20 is bonded to the first electrode substrate 10, and the electrophoretic particles in the electrophoretic ink precursor A from which the solvent has been removed are dispersed in the electrophoretic ink precursor B. Thus, the electrophoretic ink C is obtained, and the electrophoretic display device 30 shown in FIGS. 2C and 4C is manufactured.

In the method of the present invention, after the electrode substrates 10 and 20 are bonded to each other in the above-described step to form an electrophoretic ink, another light-transmitting electrode is provided on the substrate according to the use (use application, rewriting method, etc.) of the electrophoretic display device. It is also possible to bond with a non-light-transmissive electrode, a resin film, a resin, wood, metal, ceramics, paper, cloth and / or glass.
Moreover, when a resin film is used for the substrate, the effect can be increased by bonding a resin film having a solvent permeation suppressing effect or a gas permeation suppressing effect or other base material.
In addition, in order to increase the strength of the electrophoretic display device, it is possible to attach and reinforce another base material, or to attach paper or cloth as another base material for decoration of the display device.

In the method of the present invention configured as described above, a step of forming a plurality of cells 15, 15... Composed of insulating structures 16, 16... On the first electrode substrate 10, and at least one kind of cells. The step of filling the cells 15, 15... With the electrophoretic ink precursor A containing electrophoretic particles and a solvent, the step of removing the solvent from the electrophoretic ink precursor A, and the upper surface of the structure 16. The step of removing the electrophoretic particles 16a, 16a, the step of filling the cells 15, 15,... With the electrophoretic ink precursor B containing no particles, the first electrode substrate 10 and the second electrode substrate 20. And the step of dispersing the electrophoretic particles in the electrophoretic ink precursor A from which the solvent has been removed, into the electrophoretic ink precursor B, thereby simplifying the manufacturing process compared to the prior art. The step of removing the solvent from the electrophoretic ink precursor A, the step of removing the electrophoretic particles 16a, 16a present on the upper surface of the structure 16, and the electrophoretic particles in the electrophoretic ink precursor A from which the solvent has been removed Is dispersed in the electrophoretic ink precursor B, so that the electrophoretic ink can be uniformly filled without bubbles and the electrode substrate interval (gap) can be controlled uniformly and an adhesive. It is possible to provide a method for manufacturing an excellent electrophoretic display device which has a high contrast and which can suppress breakage caused by peeling of the substrates by suppressing particle mixing into the substrate.
In addition, the electrophoretic display device obtained by the method of the present invention realizes high contrast display, can display contrast with high reliability even during repeated display, has excellent responsiveness, and deteriorates display characteristics. Therefore, an electrophoretic display device with very little is obtained.

The method of the present invention is configured as described above, but is not limited to the above embodiment, and can be variously modified within the scope of the technical idea of the present invention.
For example, the electrophoretic ink precursor A may be divided into two or more types, and ink application and drying may be performed a plurality of times.

Next, examples suitable for carrying out the present invention will be shown, but the present invention is not limited thereto.
[Example 1]

An electrophoretic display device was obtained by the following steps.
1) Step of forming a plurality of cells made of an insulating structure on the first electrode substrate. As the first electrode substrate, an ITO film, which is a transparent conductive material, is formed so that the surface resistance is about 100Ω / □. A 125 μm thick PET sheet (10 × 10 cm) was used.
On this first electrode substrate, an acrylic resin photosensitive resin sheet is bonded, UV exposure, alkali development, and a plurality of grid-like cells (height 0.05 mm) made of an insulating structure. The cell size was 0.5 × 0.5 mm).

2) Step of filling the cell with electrophoretic ink precursor A Composition of electrophoretic ink precursor A used:
82% by mass of octane,
Titanium oxide particles 10% by mass
5% by mass of acrylic particles containing carbon black
Hydroxyethyl laurylamine 3% by mass
The electrophoretic ink precursor A was filled in the cell by silk printing.

3) Step of removing the solvent from the electrophoretic ink precursor A The solvent was removed from the electrophoretic ink precursor A filled by applying a 30 ° C. wind for 3 minutes to the ink precursor A filled in the cell. .

4) Step of filling the cell with the electrophoretic ink precursor B not containing particles A UV curable resin was dropped onto the outer periphery of the display area using a dispenser to form a seal portion (height 0.55 mm). Thereafter, the electrophoretic ink precursor B was filled by dropping using a dispenser.
Composition of electrophoretic ink precursor B used:
100% by weight of dodecane

5) A step of bonding the first electrode substrate and the second electrode substrate A 125 μm-thick PET sheet in which an ITO film, which is a transparent conductive material, is formed so that the surface resistance is about 100Ω / □ as the second electrode substrate. (10 × 10 cm) was used.
After aligning one end of the second electrode substrate to the first electrode substrate filled with the electrophoretic ink precursor B, it is bonded by passing between rollers placed opposite to each other, and then UV is irradiated to the seal portion By doing so, an electrophoretic display device was obtained.

6) Step of dispersing electrophoretic particles in electrophoretic ink precursor A from which solvent has been removed to electrophoretic ink precursor B Electrophoresis from which solvent has been removed by applying ultrasonic waves to the electrophoretic display device obtained above. The electrophoretic particles in the ink precursor A were dispersed in the electrophoretic ink precursor B.

Bubbles were not mixed in the display area of the obtained electrophoretic display device, and the distance between the electrode substrates was uniform. Furthermore, no electrophoretic particles were mixed in the seal portion, and there was no problem with the adhesion of the seal portion. It was confirmed that high-contrast black and white display was possible by repeating a refresh operation (alternatingly applying a voltage of ± 50 V between the electrode substrates) to this electrophoretic display device.
Furthermore, even after the obtained electrophoretic display device is allowed to stand for 1 month under 50 ° C. drying conditions, 50 ° C., and 80% humidification conditions, the display characteristics are not changed from the initial one, and the display is very resistant to display deterioration. An electrophoretic display device was obtained. In addition, the appearance of bubbles growing in the cell was not observed, the distance between the electrode substrates could be controlled uniformly, and the substrates did not peel off.

[Example 2]
An electrophoretic display device was obtained by the following steps.
In the process of Example 1, an electrophoretic display device was produced in the same manner as in Example 1 except that the cells were filled with the composition of the electrophoretic ink precursor A and the electrophoretic ink precursor B instead of the following. .
Composition of electrophoretic ink precursor used:
Electrophoretic ink precursor A:
Dodecane 57% by mass
Titanium oxide particles 20% by mass
Carbon black-containing acrylic particles 20% by mass
Hydroxyethyl laurylamine 3% by mass
Electrophoretic ink precursor B
100% by weight of dodecane

Example 3
An electrophoretic display device was obtained by the following steps.
In the process of Example 1 above, the same procedure as in Example 1 above was performed, except that the step of dispersing the electrophoretic particles in the electrophoretic ink precursor A from which the solvent had been removed was dispersed in the electrophoretic ink precursor B as follows. An electrophoretic display device was produced.
Step of dispersing electrophoretic particles in electrophoretic ink precursor A from which solvent has been removed to electrophoretic ink precursor B Electrophoretic ink precursor from which the solvent has been removed by placing the electrophoretic display in an oven at 60 ° C. for 30 minutes The electrophoretic particles in A were dispersed in the electrophoretic ink precursor B.

Example 4
An electrophoretic display device was obtained by the following steps.
In the process of Example 1 above, the same procedure as in Example 1 above was performed, except that the step of dispersing the electrophoretic particles in the electrophoretic ink precursor A from which the solvent had been removed was dispersed in the electrophoretic ink precursor B as follows. An electrophoretic display device was produced.
Dispersing the electrophoretic particles in the electrophoretic ink precursor A from which the solvent has been removed in the electrophoretic ink precursor B A voltage of ± 50 V, which is lower than the driving voltage 60 V, is alternately applied between the electrode substrates of the electrophoretic display device. Thus, the electrophoretic particles in the electrophoretic ink precursor A from which the solvent was removed were dispersed in the electrophoretic ink precursor B.

Example 5
An electrophoretic display device was obtained by the following steps.
In the process of Example 1 above, the same procedure as in Example 1 above was performed, except that the step of dispersing the electrophoretic particles in the electrophoretic ink precursor A from which the solvent had been removed was dispersed in the electrophoretic ink precursor B as follows. An electrophoretic display device was produced.
Dispersing the electrophoretic particles in the electrophoretic ink precursor A from which the solvent has been removed in the electrophoretic ink precursor B A voltage of ± 70 V, which is higher than the driving voltage 50 V, is alternately applied between the electrode substrates of the electrophoretic display device. Thus, the electrophoretic particles in the electrophoretic ink precursor A from which the solvent was removed were dispersed in the electrophoretic ink precursor B.

Example 6
An electrophoretic display device was obtained by the following steps.
In the process of Example 1 above, the same procedure as in Example 1 above was performed, except that the step of dispersing the electrophoretic particles in the electrophoretic ink precursor A from which the solvent had been removed was dispersed in the electrophoretic ink precursor B as follows. An electrophoretic display device was produced.
Electrophoretic particles in the electrophoretic ink precursor A from which the solvent has been removed are dispersed in the electrophoretic ink precursor B. Electrophoresis in which the solvent is removed by applying ultrasonic waves while heating the electrophoretic display device at 50 ° C. The electrophoretic particles in the ink precursor A were dispersed in the electrophoretic ink precursor B.

Example 7
An electrophoretic display device was obtained by the following steps.
In the process of Example 1 above, the same procedure as in Example 1 above was performed, except that the step of dispersing the electrophoretic particles in the electrophoretic ink precursor A from which the solvent had been removed was dispersed in the electrophoretic ink precursor B as follows. An electrophoretic display device was produced.
Step of dispersing electrophoretic particles in electrophoretic ink precursor A from which solvent is removed in electrophoretic ink precursor B Electrophoresis in which solvent is removed by repeating refresh operation while heating the electrophoretic display device at 60 ° C. Ink precursor A was dispersed in electrophoretic ink precursor B.

  As for the electrophoretic display devices obtained in Examples 2 to 7, the display area had no air bubbles and the spacing between the electrode substrates was uniform as described above. Furthermore, no electrophoretic particles were mixed in the seal portion, and there was no problem with the adhesion of the seal portion. It was also confirmed that high contrast black and white display was possible by alternately applying a voltage of ± 50 V between the electrode substrates of the electrophoretic display device. In addition, even after the obtained electrophoretic display device is left for one month under 50 ° C. drying conditions, 50 ° C., and 80% humidification conditions, the display characteristics are not changed from those in the initial stage, and the display is very resistant to display deterioration. An electrophoretic display device was obtained. In addition, the appearance of bubbles growing in the cell was not observed, the distance between the electrode substrates could be controlled uniformly, and the substrates did not peel off.

  Suitable manufacture of electrophoretic display devices that can be used for electronic paper such as electronic books, electronic newspapers, bulletin boards such as signboards, posters, blackboards, electronic price tags, electronic shelf labels, electronic advertisements, display units of mobile devices, etc. Is the method.

10 first electrode substrate 15 cell 16 structure 20 second electrode substrate A electrophoretic ink precursor B electrophoretic ink precursor C electrophoretic ink

Claims (6)

Forming a plurality of cells made of an insulating structure on the first electrode substrate; filling the cells with an electrophoretic ink precursor A containing at least one kind of electrophoretic particles and a solvent; Removing the solvent from the electrophoretic ink precursor A, filling the cell with the electrophoretic ink precursor B that does not contain particles, and bonding the first electrode substrate and the second electrode substrate together. And a step of dispersing the electrophoretic particles in the electrophoretic ink precursor A from which the solvent has been removed, in the electrophoretic ink precursor B, and a method for producing an electrophoretic display device. 2. The manufacturing of an electrophoretic display device according to claim 1, wherein the step of dispersing the electrophoretic particles in the electrophoretic ink precursor A from which the solvent is removed in the electrophoretic ink precursor B uses ultrasonic waves. Method. 2. The manufacturing of an electrophoretic display device according to claim 1, wherein the step of dispersing the electrophoretic particles in the electrophoretic ink precursor A from which the solvent has been removed is dispersed in the electrophoretic ink precursor B. Method. The step of dispersing the electrophoretic particles in the electrophoretic ink precursor A from which the solvent has been removed in the electrophoretic ink precursor B alternately applies a voltage between the electrodes of the electrophoretic display device. 2. A method for producing an electrophoretic display device according to 1. 5. A method for manufacturing an electrophoretic display device, wherein at least two of the manufacturing methods according to claim 2, 3, and 4 are combined. The method for manufacturing an electrophoretic display device according to claim 1, further comprising a step of removing the electrophoretic particles present on the upper surface of the structure.

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