JP5590729B2 - Method for manufacturing electrophoretic display device - Google Patents

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 recent years, demands for reducing power consumption, thinning and weight reduction, flexibility, etc. of display displays have been increasing, and electronic paper has attracted attention as one of them. An electrophoretic display device using electrophoretic ink or the like is known as one of such electronic papers. This electrophoretic display device has a configuration in which two electrode substrates, at least one of which is transparent, are arranged to face each other, and an electrophoretic ink is provided between the electrodes arranged to face each other to form a display panel. A display is obtained on the transparent electrode surface by applying an electric field to the display panel.

  The electrophoretic ink used in the present invention is one in which one or more kinds of electrophoretic particles are dispersed in a dispersion medium, and the particles move in the dispersion medium by applying an electric field from the outside. Thus, an arbitrary display is obtained. In addition to the electrophoretic particles, the electrophoretic ink may be provided with additives such as uncharged particles, surfactants, dyes, and dispersants.

Such an electrophoretic display device can obtain a desired display by moving the electrophoretic particles in the electrophoretic ink by controlling the direction of the electric field. It has the advantages of being as wide as ordinary printed matter, having low power consumption, and having a display memory property.
However, the electrophoretic particles used in the electrophoretic ink have a problem that the particles are likely to aggregate due to long-term storage, and the display is liable to be deteriorated due to uneven distribution of particles during repeated display. Therefore, there has been proposed a method for suppressing aggregation and uneven distribution of particles by dividing and filling electrophoretic ink into a large number of finely isolated cells (small compartments) (for example, Patent Document 1).

Furthermore, in order to reliably divide the cells, a method of adhering the structure forming the cells and the substrate facing the structure with an adhesive has been proposed. (For example, see Patent Document 1 and Patent Document 2)
However, the panels shown in Patent Documents 1 and 2 are display media in which powder particles are enclosed in a space between electrode substrates, and are electrophoretic panels in which an electrophoretic ink composed of both a solvent and particles is enclosed. In such a case, there is a concern that the adhesive and the electrophoretic ink are compatible or the adhesive composition components are eluted in the solvent, so that the choice of the electrophoretic ink that can not be used or can be used is limited. There are challenges.

As a method for solving this problem, there has been proposed a method of bonding a structure and a counter substrate by using an adhesive that is solid at room temperature but exhibits an adhesive force by external energy of heat.
For example, a method using a hot-melt adhesive that softens by heat energy and develops an adhesive force, or an adhesive having thermoplasticity or heat-softening properties has been proposed. (For example, see Patent Document 1, Patent Document 2, and Patent Document 3)
However, electrophoretic ink is generally weak against heat, and there is a concern that the ink is heated by a thermal process and the ink deteriorates.
A method for sealing while preventing deterioration of ink due to heat is proposed in Patent Document 4, which is a method of heating only the outer peripheral portion of a display medium. In this method, a structure disposed innumerably in the vicinity of the ink The object of the present invention for adhering and sealing can not be achieved.

趙 Kunirai and three others “New Toner Display Device (I)” July 21, 1997 Annual Meeting of the Imaging Society of Japan (83th)

JP 2006-184893 A JP 2006-184894 A JP-A-2-223936 JP-A-5-307197

The present invention has been made in view of the above-described problems of the prior art and the current situation, and solves this problem. In the case of manufacturing an electrophoretic panel in which electrophoretic ink is divided into small compartments and sealed, the substrate faces the structure. It is an object of the present invention to provide a manufacturing method that can suppress thermal deterioration of electrophoretic ink even when a heat-bonding adhesive and a heating process are used.

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 electrophoretic ink in the cells. In the method of manufacturing an electrophoretic panel, the method includes a step of filling, a step of forming an adhesive layer on the upper surface of the structure, and a step of bonding the first electrode substrate and the second electrode substrate.
In the step of bonding the first electrode substrate and the second electrode substrate, one of a pair of opposing substrates is set to a temperature different from that of the other to manufacture the electrophoretic display device for the above purpose. We found that a method was obtained and came to complete the present invention.

That is, the present invention resides in the following (1) to (5).
(1) A step of forming a plurality of cells made of an insulating structure on the first electrode substrate, a step of forming an adhesive layer on the upper surface of the structure, and filling the cell with electrophoretic ink And a bonding step of bonding the first electrode substrate and the second electrode substrate, in the bonding step, the first electrode substrate and the first electrode substrate in the bonding step. The two electrode substrates are set to different temperatures.
(2) The laminating step is performed by using a laminator composed of at least a pair of two rollers so that at least one roller of the laminator and the second electrode substrate are in contact with each other.
(3) The bonding step is performed by heating only the second electrode substrate so that the temperature of the second electrode substrate is higher than that of the first electrode substrate.
(4) The bonding step includes cooling the first electrode substrate and heating the second substrate so that the temperature of the second electrode substrate is higher than that of the first electrode substrate. Do.
(5) In the bonding step, after the first electrode substrate is cooled in advance, the second substrate is bonded while heating.

  According to the present invention, even when the upper surface of the structure and the counter electrode substrate can be bonded via the adhesive layer by a heating process, the electrophoretic display capable of suppressing the thermal deterioration of the electrophoretic ink. A method of manufacturing a device is provided.

(A)-(G) are schematic drawings explaining the manufacturing process used as an example of the manufacturing method of the electrophoretic display device of this invention for every process. (A)-(B) are the manufacturing processes used as the other example of the manufacturing method of the electrophoretic display device of this invention, and are schematic drawings for demonstrating the process different from FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram for explaining, for each process, a manufacturing process which is an example of a method for manufacturing an electrophoretic display device of the present invention (hereinafter referred to as “the present invention”).
In the present invention, as shown in FIG. 1, the step of forming an adhesive layer on the upper surface of the structure formed on the first electrode substrate [adhesive layer forming step, FIGS. 1 (A) to (C) And a step of filling an electrophoretic ink containing at least one or more types of electrophoretic particles and a solvent into a cell formed of a structure (electrophoretic ink filling step, see FIG. 1D); The first electrode substrate is disposed opposite to the second electrode substrate, and the first electrode substrate and the second electrode substrate are bonded to each other via the adhesive layer. It has a step of bonding the electrode substrate and the second electrode substrate [bonding step, see FIGS. 1E to 1G]. Below, it demonstrates concretely, referring FIG.1 (A)-(G) for every process.

The first electrode substrate 100 may be any substrate having an electrode on at least one surface. For example, as shown in FIG. 1A, a first electrode layer 102 is provided over a first base material 101. The insulating structure 103 can be formed over the first electrode layer 102.
The first substrate 101 may be transparent or opaque. For example, glass, quartz, sapphire, MgO, LiF, transparent inorganic materials such as CaF _2, fluororesin, polyester, polycarbonate, polyethylene, polyethylene terephthalate, polyethylene naphthalate, organic polymer polyether sulfone film or ceramics Can be used.

The first electrode layer 102 is made of, for example, a transparent conductive material such as ITO, ZnO, SnO ₂ , aluminum (Al), gold (Au), platinum (Pt), copper (Cu), silver (Ag), nickel It can be formed using a metal such as (Ni) or chromium (Cr). Further, conductive polymers such as PODET / PVS and PODET / PSS, and transparent conductive materials such as titanium oxide, zinc oxide, and tin oxide may be used. These materials can be formed by methods such as vapor deposition, ion plating, and sputtering.
The shape of the first electrode layer 102 can be selected as appropriate according to the shape of the second electrode layer serving as the counter electrode, and the electrode is formed in a shape along an arbitrary pattern or shape displayed on the electrophoresis panel. The segment pattern may be formed, or a dot matrix pattern in which a plurality of substantially circular or substantially square electrodes are regularly arranged. Furthermore, a TFT substrate in which a transistor element is provided for each electrode may be used.

  In the present invention, when the second electrode substrate 200 is a front-side electrode substrate, the second base 201 is used to visually recognize the display formed by the electrophoretic ink through the second electrode substrate 200. The second electrode layer 202 is preferably formed using a light-transmitting material.

<Cell formation process>
In the cell formation step, a plurality of small chambers (cells) 104, 104,... Are formed in an intermediate space between the first electrode substrate and the second electrode substrate using the insulating structure 103. (See FIG. 1A).

Since the structure is also a spacer that prevents contact between both substrates while keeping the distance (cell gap) between both substrates uniform and constant, an electrically insulating material is preferable, for example, a polyester resin fiber. A formed net (mesh) may be used, or a resin film having a certain thickness may be provided with irregularities by hot embossing or embossing, or may be formed by forming a plurality of holes by laser processing. Furthermore, the thing which provided the dry film resist or the liquid resist material to the one base material surface previously, and formed the unevenness | corrugation by photolithography may be used.
Note that an element having a structure similar to that of the structure body 103 may be referred to as a spacer, a column, a partition wall, a rib, or the like depending on the shape and purpose.

The cell 104 formed by the structure body can be provided in various shapes such as a circle, a rectangle (rectangle, square), and a hexagon. In addition, cells having a plurality of shapes and areas may exist in the same electrophoresis panel.
Since it is desirable that the cell 104 is filled with the electrophoretic ink by an ink application process, which will be described later, and the movement, uneven distribution, and aggregation of the electrophoretic particles in the electrophoretic ink can be suppressed, the cell 104 can be in close contact with at least one of the electrode substrates. It is preferable that it is possible to adhere to both substrates.
In the following description, the surface in contact with the first electrode substrate 100 is the lower surface, and the opposite side is the upper surface. In the present embodiment, a configuration in which the substrate is in close contact with one substrate (first electrode substrate) in advance will be described as an example.

<Adhesive layer forming step>
In the adhesive layer forming step, an adhesive layer 105 is formed on the upper surface of the structure 103 formed on the first electrode substrate (see FIGS. 1A to 1C).
Prior to the formation of the adhesive layer, it is desirable to remove dirt or foreign matters adhering to the upper surface of the structure 103 in advance. For example, the adhesive tape may be attached and removed, or may be attached and removed with a gel material or an elastic material. Alternatively, scrapers, squeegees, doctor blades, and the like may be scraped off, or may be adsorbed and removed with a porous material or nonwoven fabric. Furthermore, it may be cleaned with a hygroscopic material containing a solvent.

The adhesive layer 105 can be formed by using a material that exhibits an adhesive force by heating, such as a thermosetting adhesive or a thermoplastic adhesive, and it is particularly preferable to use a thermoplastic adhesive.
This is because the thermoplastic adhesive is cooled only after the adhesive layer 105 is formed on the upper surface of the structure 103 in a state of being melted or softened by heating, thereby fixing the adhesive only on the upper surface of the structure 103. This is because it is possible to suppress the inflow of the adhesive into the cell in the ink application process described later.
Furthermore, it is because it becomes possible to adhere | attach substrates by heating again in the bonding process mentioned later.

In the case where a thermosetting adhesive is used, the adhesive layer 105 is formed so that the adhesive applied to the upper surface of the structure body 103 can suppress inflow into the cell in the bonding process described later. Is preferred.
For example, after the adhesive is applied to the upper surface of the structure 103, it is semi-cured by heating to the minimum necessary to fix the adhesive, and then completely cured by heating again in the bonding process. The method of making it adhere | attach can be mentioned.
Here, the semi-curing is a state in which the reaction of the reactive adhesive is less than complete curing, and the viscosity of the adhesive increases from the initial value, but the adhesiveness is developed by further advancing the reaction. Refers to the state.

In the present invention, the adhesive layer 105 can be formed using various methods such as gravure printing, screen printing, ink jetting, and transfer in accordance with the characteristics of the adhesive to be used, and it is particularly preferable to use the transfer method. .
In this embodiment mode, a thermoplastic adhesive and a transfer method are used. As shown in FIGS. 1A to 1C, a base material 300 having an adhesive 301 formed on a surface thereof is attached to a structure 103. A part of the adhesive can be transferred to the upper surface of the structure 103 by peeling off after contacting the upper surface. This transfer method is preferable because the adhesive layer 105 can be selectively and easily formed on the upper surface of the structure 103.
The thickness of the adhesive layer 105 (film thickness after drying) is preferably 2 to 10 μm as a condition for obtaining a sufficient adhesive force. In addition, the thickness of the adhesive layer 105 needs to be determined in consideration of display performance in order to determine the distance (cell gap) between two opposing substrates. In addition, the adhesive layer 105 is preferably formed over the entire top surface of the structure body 103 in consideration of adhesion between two opposing substrates and an effect of suppressing migration of electrophoretic particles.

<Electrophoretic ink filling process>
In the electrophoresis ink filling step, the cells 104, 104,... Formed on the first electrode substrate 100 are filled with the electrophoresis ink.
As a method of filling the electrophoretic ink, for example, it is applied by coating with a die coater or the like, or the electrophoretic ink disposed at an arbitrary position of the first electrode substrate is substantially contacted by a bar coater, a doctor blade, a comma roll, or the like. It may be spread out, or may be filled in a non-contact manner by a printing method using screen printing or the like, or an inkjet or a dispenser. Any other method can be used as long as it can fill the cells with ink.
In the drawing of the present embodiment, as shown in FIG. 1D, electrophoretic ink is applied and filled using a die coater 106.

The electrophoretic ink used in the present invention may be any ink that contains at least one kind of electrophoretic particles and a solvent such as a solvent.
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.
As a specific example, it can be formed with positively charged white particles, negatively charged black particles, and a solvent (solvent) in which these particles are dispersed. As the white particles, white pigments such as titanium oxide, white resin particles, or resin particles colored in white can be used. As the black particles, black pigments such as titanium black and carbon black, resin particles colored in black, and the like can be used. These particles can be arbitrarily used in various colors as long as the contrast can be displayed, and can be a combination of white and red, white and blue, yellow and black, and the like. Alternatively, only one type of charged particle such as only white particles or only black particles may be used.
These electrophoretic particles have an average particle diameter of 0.05 to 20 μm, and particularly preferably an average particle diameter of 0.1 to 10 μm.
In addition, 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. In particular, it is preferable to use a hydrocarbon solvent having at least 10 to 18 carbon atoms because it is transparent and has a low dielectric constant (desirably 5.0 or less).
The solvent is preferably contained in an amount of 25 to 85%, more preferably 30 to 60%, based on the total amount of electrophoretic ink. This is because if it is less than 25%, the viscosity of the liquid increases and the response speed becomes slow. On the other hand, if it exceeds 85%, sufficient contrast cannot be displayed, which is not preferable.

Further, in addition to one or more types of electrophoretic particles and a solvent, a dispersant and a charge control agent may be further contained. 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. Examples thereof include, but are not limited to, system surfactants and polymer surfactants. The content of these dispersants is appropriately determined depending on the electrophoretic particles and solvent type to be used, but is preferably 0.01 to 50.0% with respect to the total amount of electrophoretic ink, More preferably, it is contained so that it may become 0.5 to 30%.
As the charge control agent, various types used for electrophoretic display can be used.

When filling with electrophoretic ink, the gas dissolved or entrained in the electrophoretic ink is removed, and gas such as air does not enter the display area as much as possible before, during, or after filling. Or it is preferable not to remain.
As a specific method, each step is performed in a reduced pressure environment, or after each is applied, it is allowed to stand in a reduced pressure environment.
As a result, the gap between the electrophoretic ink and the replacement of the air in the cell with the electrophoretic ink can be promoted, and the possibility of bubbles remaining in the panel can be reduced. Since mixing of bubbles between the substrates after sealing) is suppressed, display unevenness, display defects, deterioration due to bubble growth, etc. are suppressed, and an electrophoretic display device having stable display quality over a long period of time is obtained. Is possible.

As another method, a wettability adjusting step for improving the wettability of the electrophoretic ink may be added to the surface of the application surface in advance before filling with the electrophoretic ink.
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, Methods of ion beam treatment, ion irradiation treatment, primer treatment, surfactant treatment, sputtering treatment, PVD (physical vapor deposition), CVD (chemical vapor deposition), polymer layer formation and inorganic layer formation Etc. 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.
The electrophoretic ink is sufficiently distributed to the inner walls and corners of the plurality of cells 104, 104... Made of the insulating structure 103, and a plurality of cells made of a gas such as air is made of the insulating structures 103, 103. 104, 104... Is a preferred process for expelling from within.

As a method for removing the gas contained in the electrophoretic ink before filling, for example, a method of stirring the electrophoretic ink with a stirring rod, a method of heating, a method of stirring while heating, a method using ultrasonic waves , A method using reduced pressure, a method using centrifugal force, a method using an additive such as an antifoaming agent, and the like. In addition, examples of the degassing method when filling the electrophoretic ink 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 electrophoretic ink, there are a method of applying ultrasonic waves to the substrate after filling, a method of heating, a method of centrifugal force, a method of keeping under reduced pressure, a method of leaving for a certain time, etc. Although it is mentioned, it is not limited to these.
Furthermore, these methods may be used in combination.

<Lamination process>
In the bonding step, as shown in FIG. 1D, the adhesive layer 105 of the first electrode substrate 100 in which the electrophoretic ink is filled in the cells 104, 104. An electrophoretic display device is manufactured by bonding.
The bonding may be a flat plate heating press in which the substrates are arranged substantially in parallel and pressed on the surface, or heat composed of a pair of heatable rollers as shown in FIGS. You may paste together with a laminator.
Alternatively, one may be a flat plate and one may be a roller.

Since a heat-adhesive adhesive is used for bonding, it is necessary to heat the adhesive 105 so as to rise to a desired temperature. At the same time, in order to suppress thermal degradation of the electrophoretic ink held in the cell, it is desirable to maintain the vicinity of the ink at a low temperature.
Specifically, a method of heating at least the adhesive layer 105 or the second substrate 200 which is an adherend surface to which the adhesive layer 105 is bonded can be given.
In particular, when only the second electrode substrate 200 is selectively heated, the heat is transferred to the second electrode base material 200, the temperature of the surface in contact with the adhesive layer 105 is increased, and the adhesiveness of the adhesive layer 105 is increased. To express. Since the first electrode substrate 100 facing each other at the same time is kept at room temperature, excess heat is conducted through the electrophoretic ink 106 or the structure 103 and the first electrode substrate 100 to enter the nearby air. Heat is dissipated.

As a method for selectively heating only the second electrode substrate, only the side of the flat plate or roller that contacts the second substrate is heated in advance, and heat is generated by contacting the second substrate. The method of conducting and heating is mentioned.
Other methods include heating by convection with heated air, heating by radiation by irradiating strong red light or infrared light, heating by oscillating the second substrate by ultrasonic vibration, strong magnetic field However, the method is not limited to this.

A more preferable method includes a method of selectively cooling the first electrode substrate. Thereby, the electrophoretic ink 106 held in the cell 104 can be more reliably maintained at a lower temperature than the method of bonding only by heat radiation to room temperature. In particular, it is a preferable method when heating at a high temperature is required, when heating for a long time is required, or when an electrophoretic ink that easily undergoes thermal degradation is used.

As a method of selectively cooling only the first electrode substrate 100, only the side of the flat plate or roller that contacts the first substrate is cooled in advance, and heat is obtained by contacting the first substrate. There is a method of conducting and cooling.
Besides, a method of cooling by convection with cooling air, a method of contacting a third member different from a flat plate or roller used for bonding, and conducting heat to the third member side, A method of passing a fluid through the third member and conducting heat to the fluid may be used, but the method is not limited thereto.

As another method, the first electrode substrate 100 may be cooled in advance. When the thermal capacity of the entire first substrate is large, such as when the ink is not heated excessively even after the bonding process, or when the substrate is thick or when a metal or glass substrate is used. Is an effective method.

  As the second electrode substrate 200 used in the present invention, for example, a transparent conductive material such as ITO is formed on a transparent resin film, transparent glass, or the like by a deposition method such as a coating method, an ion plating method, or a sputtering method. 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. In addition, when the first electrode substrate 100 and the second electrode substrate 200 are bonded together, the bonding process may be performed in a vacuum to prevent air bubbles from entering the display area.

After creating an electrophoretic panel by the above method, another light transmissive electrode, non-light transmissive electrode, resin film, resin on the substrate according to the use (use application, rewriting method, etc.) of the electrophoretic display device It is also possible to bond with 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.

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

(Example 1, conforming to FIG. 1)
<Cell formation process>
An acrylate-based resist film was bonded to a first electrode substrate (an electrode substrate on which a metal layer pattern was formed on a glass epoxy substrate) using a vacuum laminator, and then a honeycomb shape was continuously formed by a photoresist method. A structure 103 having a plurality of cells 104 was formed.

<Adhesive layer forming step>
A thermoplastic adhesive diluted with a solvent (hot melt resin, Byron 55ss, manufactured by Toyobo Co., Ltd.) on a PET film (trade name “Lumirror”, thickness 50 μm, manufactured by Toray Industries, Inc.) is formed into a film thickness of 12 μm using a comma roll. After application, it was dried. Next, the PET film 300 on which the layer of the thermoplastic adhesive 301 is formed and the first electrode substrate 100 on which the structure 103 is formed are passed through a thermal laminator at 120 ° C. and pulled while being heated. By peeling off, a part of the thermoplastic adhesive 301 formed on the PET film 300 was transferred to the upper surface of the structure 103 to form the adhesive layer 105. The thickness of the adhesive layer 105 formed on the entire top surface of the structure 103 was 5 to 8 μm.

<Electrophoretic ink filling process>
After the thermoplastic adhesive layer 105 formed on the upper surface of the structure 103 is sufficiently cooled, the electrophoretic ink 106 [white particles (lipophilic surface-treated) is applied to the first electrode substrate 100 using the die coater 400. Titanium oxide 10% by mass, negatively charged), black particles (acrylic particles colored by carbon black 10% by mass, positively charged), hydroxylaurylamine 3% by mass, Isopar G77% by mass as solvent (exxon mobile, boiling point) 180 ° C.), the cells 104, 104... Made of the structure 103 were filled with the electrophoretic ink 106.

<Main seal application process>
Next, an ultraviolet curable adhesive (TB3052D, manufactured by Three Bond Co., Ltd.) was applied to the outer periphery of the portion to which the electrophoretic ink 106 was applied using a dispenser to form a main seal portion.

<Lamination process>
The lamination was made of a pair of upper and lower rollers, and a thermal laminator capable of individually heating each roller was used.
After the first electrode substrate 100 and the second electrode substrate 200 are bonded together through a thermal laminator, the main seal portion formed on the outer periphery of the electrophoretic ink application portion is irradiated with ultraviolet rays to cure ultraviolet rays. An electrophoretic display panel was produced by curing the mold adhesive.
The set temperature of the thermal laminator in the bonding step was 120 ° C. for the upper roller 401 in contact with the first electrode substrate and no heating (room temperature 26 ° C.) for the lower roller 402 in contact with the second electrode substrate.

(Example 2, conforming to FIGS. 1 and 2)
After passing through the cell forming step, the adhesive layer forming step, the electrophoresis ink filling step, and the main seal coating step described in Example 1, a panel was prepared through the following bonding step.
<Lamination process>
For the bonding, a flat press was used which consisted of two flat plates arranged in parallel in a pair of upper and lower sides and which can individually heat each flat plate. Each flat plate can fix the first electrode substrate 100 and the second electrode substrate 200, respectively, and can adjust the relative position of each. Moreover, a series of apparatus is arrange | positioned in the tank and can adjust an environment and a pressure suitably.
The first electrode substrate 100 is fixed to the lower flat plate of the flat plate press with the electrode surface and the ink application surface facing upward, and the second electrode substrate 200 is faced to the upper flat plate with the electrode surface facing downward. And fix.
Next, the upper flat plate was heated to heat the second electrode substrate 200 to 120 ° C., and then brought into contact with the lower first electrode substrate 100, and further bonded together under a load for several seconds.
After bonding, the main seal part formed on the outer periphery of the electrophoretic ink application part was irradiated with ultraviolet rays to cure the ultraviolet curable adhesive, thereby producing an electrophoretic display panel.

(Example 3, figure and figure compliant)
After passing through the cell forming step, the adhesive layer forming step, the electrophoresis ink filling step, and the main seal coating step described in Example 1, the cold air blower from below the laminator device during the same bonding step as in Example 1 Then, the first electrode substrate was bonded to the first electrode substrate while applying cold air.

(Example 4, figure and figure compliant)
After cooling the first electrode substrate described in Example 1 through the cell formation step and the adhesive layer formation step to 5 ° C., the filling step of the electrophoretic ink described in Example 1, the main seal application step, A panel was created through a bonding process.

(Comparative Example 1)
In the same manner as in Example 1, after undergoing the cell formation step, the adhesive layer formation step, the electrophoresis ink filling step, and the main seal coating step, an electrophoresis panel was produced through the following bonding step.

<Lamination process>
The first electrode substrate coated with the electrophoretic ink and the second electrode substrate were aligned through the first adhesive layer, and then bonded through a thermal laminator to form the outer periphery of the cell forming portion. An electrophoretic display panel was produced by irradiating the main seal part with ultraviolet rays to cure the ultraviolet curable adhesive.
The set temperature of the thermal laminator in the bonding process was set to 120 ° C. for both the upper and lower rollers, and the substrate was not preheated or cooled.

Examples 1, 2, 3, and 4 are examples in which the second substrate is held at a temperature higher than that of the first substrate, and the heating and cooling methods are different.
Comparative Example 1 is different from Examples 1, 2, 3, and 4 in that both the first substrate and the second substrate are heated to the bonding temperature.

Using the electrophoresis panels prepared by the methods of Examples and Comparative Examples, evaluation was performed by the following method.
(Test Example 1: Evaluation 1)
<Display evaluation>
Each electrophoretic display panel produced by the method of the example and the comparative example is placed horizontally (in a state where it is placed in parallel with the ground), and + 50V and −50V voltages are alternately applied between the electrodes of the electrophoretic display panel. And the black and white display was switched to measure the reflectance. The results are shown in the table.

The reflectance was measured using a spectrocolorimeter [SC-T (P), manufactured by Suga Test Instruments Co., Ltd.].
As measurement conditions,
Optical conditions: Diffuse illumination 8 ° light reception d8 method (excluding regular reflection)
Light source: 12V50W halogen lamp Color measurement condition: D65 light 10 ° Field of view Measurement area: 5φ
Was used.
<Evaluation criteria>
○: Display contrast equivalent to the electrophoresis panel prepared without heat bonding △: Display contrast is inferior to the electrophoresis panel prepared without heat bonding, but operates
X: Almost no operation and display contrast is not obtained

(Test Example 2: Evaluation 2)
<Adhesive strength evaluation>
A part of each electrophoresis panel prepared by the methods of Examples and Comparative Examples was peeled by hand, and the peel strength was evaluated according to the following evaluation criteria based on hand feeling and visual observation.
The results are shown in Table 1.
<Evaluation criteria>
○: Necessary and sufficient adhesive force is expressed.
Δ: Inadequate but develops adhesive strength ×: Adhesive strength is insufficient and measurement is not possible

  As is apparent from the results in the above table, Examples 1 to 4 within the scope of the present invention were found to have better display characteristics than Comparative Example 1 outside the scope of the present invention. Moreover, it turned out that adhesive force is not inferior even compared with the comparative example 1 which heated both.

DESCRIPTION OF SYMBOLS 100 1st electrode substrate 101 1st base material 102 1st electrode layer 103 Structure 104 Cell 105 Adhesive layer 106 Electrophoretic ink 200 2nd electrode substrate 201 2nd base material 202 2nd electrode layer 300 Base material 301 Adhesive 400 Die coater 401 Upper roller 402 Lower roller 403 Metal plate

Claims (2)

A step of forming a plurality of cells made of an insulating structure on the first electrode substrate, a step of forming an adhesive layer on the upper surface of the structure, at least one type of electrophoretic particles and a solvent, etc. a step of filling the electrophoretic ink comprising a solvent in the cell, in the manufacturing method of the first electrode substrate and the electrophoretic display medium having a bonding step bonding the second electrode substrate, said bonding The step uses a laminator composed of at least a pair of two rollers so that at least one roller of the laminator and the second electrode substrate are in contact with each other, and the second electrode substrate is more than the first electrode substrate. A method for producing an electrophoretic display medium, which is performed by cooling the first electrode substrate and heating the second substrate so that the temperature of the electrode substrate is increased .   2. The method for manufacturing an electrophoretic display medium according to claim 1, wherein, in the bonding step, the first electrode substrate is cooled in advance, and then the second substrate is bonded while being heated.

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