JP2012032638A - Method for manufacturing electrophoretic display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for easily manufacturing an electrophoretic display device in which substrates are laminated by forming an adhesive layer on the both substrates, the method capable of suppressing reduction in the adhesive force and reduction in display contrast.SOLUTION: The method includes steps of: forming a plurality of cells 104 composed of an insulating structure standing on a first electrode substrate 100; forming a first adhesive layer 105 on an upper face of the structure; bringing a second electrode substrate 200 into contact with the upper face of the structure where the first adhesive layer is formed; forming a second adhesive layer 203 on the surface of the second electrode substrate by peeling the second electrode substrate from the upper face of the structure so as to transfer a part of the first adhesive layer formed on the upper face of the structure onto the surface of the second electrode substrate; filling the plurality of cells with an electrophoretic ink; and laminating the first electrode substrate with the second electrode substrate by adhering the first adhesive layer with the second adhesive layer.

Description

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

  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. The electrophoretic display device has a configuration in which two electrode substrates, at least one of which is transparent, are arranged so as to face each other, and an electrophoretic ink is provided between the opposed electrodes, thereby forming a display panel. A display is obtained on the transparent electrode surface by applying an electric field to the display panel.

  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 viewing angle as wide as that of a normal printed material, consumes little power, and has a display memory property. It has attracted attention because it has advantages such as 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 particles are unevenly distributed during repeated display. Therefore, there has been proposed a method for suppressing aggregation and uneven distribution of particles by filling electrophoretic ink into a number of finely separated small compartments (cells).

  The small compartment (cell) has a method of forming using microcapsules, embossing, photoresist, etc., but when using a method other than microcapsules, in order to suppress aggregation and uneven distribution of electrophoretic particles, It is necessary to adhere the structure (referred to as a spacer, a column, a rib, or the like) formed on one substrate side with an adhesive or the like so that there is no gap between the other substrate. Therefore, a method has been proposed in which the upper surface of the structure and the counter substrate are bonded via an adhesive (see, for example, Patent Document 1 and Patent Document 2).

JP 2009-251214 A JP 2006-184893 A

  However, when the opposite substrate surface is wetted with the electrophoretic ink first when the substrates are pasted after the electrophoretic ink is filled in the structure cell, the adhesive strength of the adhesive layer is reduced. This causes a problem that the adhesive force between the electrode substrates is not sufficient. This problem makes it easier for the opposing electrode substrates to be peeled off, causing the electrophoretic ink to leak out, and the electrophoretic particles to move through the gap formed between the structure and the electrode substrate. The problem that it becomes impossible to suppress aggregation and uneven distribution of the electrophoretic particles occurs, and the structural durability and display durability of the electrophoretic display device are lowered.

  Further, even when an adhesive layer is formed on the electrode substrate side facing the structure and adhered to the upper surface of the structure, the same problem as described above is caused by the electrophoretic ink attached to the upper surface of the structure.

  As a means for solving these problems, a method in which an adhesive layer is formed on both the upper surface of the structure and the surface of the electrode substrate facing the structure is bonded. This is because the adherend in the amorphous state, such as the applied adhesive, rather than the property of the adhesive that the similar thing, the same thing adhere better, and the generally stable substrate surface It is a product that utilizes the property of the adhesive to adhere more firmly, and is an effective means for improving the adhesive strength.

  However, when a layer such as an adhesive is formed on the entire surface of the electrode substrate, the display contrast is lowered by applying a desired voltage to the electrophoretic ink during driving, or a higher driving is performed to express the desired display contrast. A voltage is required.

  As a means for solving this problem, a method of forming an adhesive layer in the same pattern (pattern shape) as the upper surface shape of the structure by, for example, a screen printing method on the electrode substrate surface facing the structure can be considered. New issues such as the complexity of the process, the positioning accuracy of both, and the adjustment of dimensional and shape variations for each material can be considered.

  The present invention has been made in view of the above points, and is formed on both electrode substrates even when an adhesive layer having an approximate shape is formed on both of the opposing electrode substrates and bonded together. An object of the present invention is to provide a method for easily producing an electrophoretic display device that suppresses variations in the pattern shape of the adhesive layer and reduces the complexity of the process, and suppresses a decrease in adhesive strength and display contrast of both electrode substrates. One of them.

  One aspect of the method for manufacturing an electrophoretic display device of the present invention includes a step of forming a plurality of cells formed of an insulating structure standing on a first electrode substrate, and a first surface on the upper surface of the structure. A step of forming an adhesive layer, a step of bringing the second electrode substrate into contact with the upper surface of the structure on which the first adhesive layer is formed, and peeling the second electrode substrate from the upper surface of the structure. Transferring a part of the first adhesive layer formed on the upper surface of the structure to the surface of the second electrode substrate, and forming the second adhesive layer on the surface of the second electrode substrate; , By filling the plurality of cells with the electrophoretic ink, and by arranging the first electrode substrate and the second electrode substrate to face each other and bonding the first adhesive layer and the second adhesive layer, Bonding the first electrode substrate and the second electrode substrate.

  In the method for manufacturing an electrophoretic display device of the present invention, the step of forming the first adhesive layer on the upper surface of the structure is performed after bringing the base material having the adhesive layer formed on the surface into contact with the upper surface of the structure. It is preferable that a part of the adhesive layer formed on the surface of the base material is transferred to the upper surface of the structure body by peeling off from the upper surface of the structure body to form the first adhesive layer on the upper surface of the structure body.

  In the method for manufacturing an electrophoretic display device of the present invention, a structure in which a first adhesive layer in a step of filling a plurality of cells with electrophoretic ink is formed, and a second electrode substrate is formed with the first adhesive layer. It is preferable that the first adhesive layer in the step of contacting the upper surface of the substrate is cured.

  According to the present invention, it is possible to suppress variations in the pattern shape of the adhesive layers formed on both substrates, even when the adhesive layers having approximate shapes are formed on both opposing substrates, respectively, and bonding is performed. It is possible to easily manufacture an electrophoretic display device by reducing the complexity of the process. In addition, as a result, it is possible to suppress a decrease in the adhesive force between the opposing substrates and to sufficiently partition each cell, and thus it is possible to simply provide an electrophoretic display device capable of suppressing a reduction in display contrast. .

It is a figure explaining an example of the manufacturing method of an electrophoretic display device. It is a figure explaining an example of the manufacturing method of an electrophoretic display device. It is a figure explaining an example of the 1st adhesive bond layer formation process in the manufacturing method of an electrophoretic display device. It is a figure explaining the pattern shape of a 1st adhesive bond layer and a 2nd adhesive bond layer.

  The inventor forms an adhesive layer having substantially the same pattern shape on both the upper surface side of the structure formed on the first electrode substrate and the second electrode substrate side by transfer, and performs electrophoresis. By laminating using the adhesive layer formed on both electrode substrates after filling with ink, the upper surface of the structure and the second electrode substrate are firmly bonded without impairing the display performance in a simple process. The knowledge that it can adhere was acquired. Hereinafter, an example of the electrophoretic display device and the manufacturing method thereof according to the present invention will be described.

  The manufacturing method of the electrophoretic display device described in this embodiment includes a step of forming a plurality of cells formed of an insulating structure erected on a first electrode substrate, and a first surface on the upper surface of the structure. Forming the adhesive layer, contacting the second electrode substrate with the upper surface of the structure on which the first adhesive layer is formed, and peeling the second electrode substrate from the upper surface of the structure. Transferring a part of the first adhesive layer formed on the upper surface of the structure to the surface of the second electrode substrate, and forming the second adhesive layer on the surface of the second electrode substrate; , By filling the plurality of cells with the electrophoretic ink, and by arranging the first electrode substrate and the second electrode substrate to face each other and bonding the first adhesive layer and the second adhesive layer, A step of bonding the first electrode substrate and the second electrode substrate together. Below, each process is demonstrated concretely with reference to drawings.

<Cell formation process>
In the cell formation step, a plurality of small chambers (cells 104) each including an insulating structure 103 provided on the first electrode substrate 100 are formed (see FIG. 1A). The plurality of cells 104 are separated from each other by the standing structure 103 and can be provided in various shapes such as a circle, a rectangle (rectangle, square), and a hexagon. In addition, the structure 103 may be referred to as a “rib” or a “spacer”.

  The first electrode substrate 100 may be a substrate having electrodes. For example, the first electrode substrate 100 has a structure in which a first electrode layer 102 is provided on a first base 101 as shown in FIG. An insulating structure 103 can be formed over the layer 102.

The first substrate 101 is made of a transparent inorganic material such as glass, quartz, sapphire, MgO, LiF, or CaF ₂ , an organic polymer film such as fluorine resin, polyester, polycarbonate, polyethylene, or polyethylene terephthalate, or ceramic. Can be formed.

The first electrode layer 102 is made of a transparent conductive material such as ITO, ZnO, SnO ₂ , aluminum (Al), gold (Au), platinum (Pt), copper (Cu), silver (Ag), nickel (Ni ), A metal such as 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 1st electrode layer 102 can be suitably selected according to the shape of the 2nd electrode layer used as a counter electrode. Note that the first electrode layer 102 may be provided in contact with the first base material 101, or a TFT element or the like may be provided over the first base material 101.

  In the electrophoretic display device, when the first electrode substrate 100 is the front electrode substrate, the first electrode substrate 100 is used to visually recognize the display of characters and the like formed from the electrophoretic ink. The base material 101 and the first electrode layer 102 are preferably formed using a light-transmitting material.

  The structure 103 can be formed using a resin material such as a PET film. For example, a plurality of cells 104 can be formed by laser processing a synthetic resin such as a PET film having a certain thickness to form a shape such as a square, hexagon, or circle. Further, after an insulating layer is formed over the first electrode layer 102, the plurality of cells 104 can be formed by patterning the insulating layer using a photolithography method. In addition, a thermoplastic resin can be formed over the first electrode layer 102, and the cell 104 made of the cross-shaped structure 103 can be formed by a method such as hot embossing.

<First adhesive layer forming step>
In the first adhesive layer formation step, the first adhesive layer 105 is formed on the upper surface of the structure body 103 (see FIG. 1B).

  For the first adhesive layer 105, various adhesives such as a thermosetting adhesive, a thermoplastic adhesive, and a photocurable adhesive can be used, and it is particularly preferable to use a thermoplastic adhesive. In the thermoplastic adhesive, the first adhesive layer 105 is formed on the upper surface of the structure body 103 while being melted or softened by heating, and then the adhesive is fixed only on the upper surface of the structure body 103 by cooling. be able to. This makes it possible to suppress the inflow of the adhesive into the cell. Furthermore, since it can be melted or softened by heating again after filling the electrophoretic ink, the substrates can be bonded together in the bonding step.

  Further, even when a thermosetting adhesive or a photocurable adhesive is used, the first adhesive layer 105 may be formed so as to suppress the inflow of the adhesive from the upper surface of the structure 103 into the cell. preferable. For example, the heat is applied to the upper surface of the structure 103 to the extent that the adhesive can be fixed, or is semi-cured by irradiation with ultraviolet rays, and then completely adhered and cured by heating or ultraviolet irradiation again in the bonding process. The method etc. can be mentioned.

  The first adhesive layer 105 can be formed using various methods such as gravure printing, screen printing, ink jetting, transfer, and the like in accordance with the characteristics of the adhesive to be used, and it is particularly preferable to use a transfer method. In the case of using the transfer method, the base material 300 on which the adhesive 302 is formed is peeled after being brought into contact with the upper surface of the structure 103, whereby a part of the adhesive is applied to the surface of the base material 103. It can be transferred to the upper surface (see FIGS. 3A to 3C). This is because the first adhesive layer 105 can be selectively and easily formed on the upper surface of the structure 103 by using the transfer method. Note that in the case where the first electrode substrate 100 is a flexible substrate, the efficiency of the manufacturing process can be improved by performing transfer using a roll process.

<Contact process>
Next, the second electrode substrate 200 is brought into contact with the upper surface of the structure 103 on which the first adhesive layer 105 is formed (see FIG. 1C).

  When the second electrode substrate 200 and the first adhesive layer 105 are brought into contact with each other, it is preferable that the first adhesive layer 105 is in a softened state. For example, when a thermoplastic adhesive is used as the first adhesive layer 105, the second electrode is formed after the first adhesive layer 105 is formed on the upper surface of the structure 103 and then cooled and fixed. What is necessary is just to make it contact with the board | substrate 200. FIG. In addition, when the first adhesive layer 105 is in a fixed state, the first adhesive layer 105 is heated or melted or softened before being brought into contact with the second electrode substrate 200, What is necessary is just to contact the 2nd electrode substrate 200. FIG. In the case where a thermosetting adhesive or a photocurable adhesive is used as the first adhesive layer 105, the first adhesive layer 105 is formed on the upper surface of the structure 103 and then heated or irradiated with ultraviolet rays. The second electrode substrate 200 may be contacted before being cured.

<Second adhesive layer forming step>
Next, a part of the first adhesive layer 105 formed on the upper surface of the structure 103 is transferred to the surface of the second electrode substrate 200 by peeling the second electrode substrate 200 from the structure 103. . As a result, the second adhesive layer 203 having substantially the same pattern as the pattern shape of the upper surface of the structure 103 can be formed on the surface of the second electrode substrate 200 (see FIG. 1D).

  The second electrode substrate 200 may be formed of a substrate provided with an electrode. For example, the second electrode layer 200 may be provided on the second base material 201. Note that the second base 201 may be formed using any of the materials shown in the description of the first base 101. The second electrode layer 202 may be formed using any one of the materials described in the description of the first electrode layer 102. In the electrophoretic display device, when the second electrode substrate 200 is a front electrode substrate, the display of characters or the like formed from the electrophoretic ink through the second electrode substrate 200 is visually recognized. The second base 201 and the second electrode layer 202 are preferably formed using a light-transmitting material.

  In addition, the first adhesive layer 105 remaining on the upper surface of the structure body 103 can be fixed by cooling after peeling the second electrode substrate 200 from the structure body 103. Thereby, it is possible to suppress the inflow of the adhesive into the cell 104 and the like, and to prevent the first adhesive layer 105 from being dissolved in the electrophoretic ink in the electrophoretic ink filling step performed later. Become.

  Further, in the case where a thermosetting adhesive or a photocurable adhesive is used as the first adhesive layer 105, the minimum necessary amount that can be fixed after peeling the second electrode substrate 200 from the structure body 103. It is preferable that the first adhesive layer 105 remaining on the upper surface of the structure 103 is semi-cured by heating or irradiating with ultraviolet rays, and then completely adhered and cured by heating or irradiating with ultraviolet rays again in the bonding step. .

  As described above, the first adhesive layer 105 in the electrophoretic ink filling process to be performed later is set to be harder than the first adhesive layer 105 in the contact process, whereby the second adhesive to the second electrode substrate 200 is performed. The adhesive layer 203 is satisfactorily formed and the inflow of the adhesive into the cell 104 and the dissolution of the first adhesive layer 105 in the electrophoretic ink are suppressed in the electrophoretic ink filling step. It becomes possible. Here, the cured state refers to a state in which the viscosity has increased or a state in which the fluidity has decreased. Specifically, the first adhesive layer 105 in the electrophoresis ink filling step is the first in the contact step. Compared with the adhesive layer 105, a state in which the viscosity of the whole layer is increased (a state in which fluidity is lowered) is indicated. The cured state includes a semi-cured state where the curing is not complete, and the cured state of the first adhesive layer 105 in the electrophoretic ink filling step is a semi-cured state, and further in the bonding step. One adhesive layer 105 is cured.

  As described above, the structure 103 having the first adhesive layer 105 formed on the upper surface is brought into contact with the second electrode substrate 200 and then peeled off, whereby the structure 103 is formed on the surface of the second electrode substrate 200. It is possible to easily form the second adhesive layer 203 that has substantially the same pattern as the pattern shape of the upper surface and is made of the same material.

  Note that the pattern shape on the upper surface of the structure 103 is substantially the same as that on the second electrode substrate 200 so as to correspond to the pattern shape on the upper surface of the structure 103, as shown in FIGS. The second adhesive layer 203 is formed, and preferably, the center of the width W1 of the first adhesive layer 105 and the width of the second adhesive layer 203 in FIG. This represents a state in which the centers of W2 coincide. W1 = W2 is preferable, but when the first electrode substrate 100 and the second electrode substrate 200 are strongly pressed in the contact step, the width of the structure 103 and the second adhesive layer 203 There are cases where either of the widths becomes wider (W1> W2 or W1 <W2). 4A is a cross-sectional view, FIG. 4B is a plan view of the second electrode substrate 200, and FIG. 4C is a plan view of the first electrode substrate 100. ing.

<Electrophoretic ink filling process>
In the electrophoretic ink filling step, the electrophoretic ink 106 is filled into the cells 104 formed on the first electrode substrate 100 (FIG. 2A). As a method of filling the electrophoretic ink 106, for example, a coating method using a die coater, a printing method using screen printing, or a method that can fill the cell with ink such as ink jet or dispenser filling. If there are, various methods can be used.

  The electrophoretic ink 106 only needs to contain at least one kind of electrophoretic particles. For example, the electrophoretic ink 106 is formed of positively charged white particles, negatively charged black particles, and a dispersion medium in which these particles are dispersed. can do. 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 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.

<Lamination process>
In the bonding step, the first electrode substrate 100 and the second electrode substrate 200 are arranged to face each other, and the top surface of the structure body 103 and the second electrode substrate 200 are interposed through the first adhesive layer 105 and the second adhesive layer 203. By adhering the electrode substrate 200, the electrophoretic ink 106 is sealed in the cell 104 (see FIG. 2B). Note that when the first electrode substrate 100 and the second electrode substrate 200 are disposed to face each other, the upper surface pattern of the structure 103 and the pattern of the second adhesive layer 203 formed on the second electrode substrate 200 are overlapped. Align so that

  As described above, when the first adhesive layer 105 provided on the upper surface of the structure 103 and the second adhesive layer 203 provided on the second electrode substrate 200 are bonded to each other, Since the adhesive layer is formed, the adhesive force can be improved as compared with the case where the adhesive layer is provided only on the upper surface of the structure 103 or one side of the second electrode substrate 200.

  According to this embodiment, since the adhesive layer is formed on the surfaces of the second electrode substrate 200 and the structure 103 which are adherends in advance, the electrophoretic particles, the surfactant in the electrophoretic ink 106, and the like Without intervening, it is possible to suppress a decrease in adhesive force. Note that there is a possibility that an electrophoretic particle or a surfactant in the electrophoretic ink 106 may be interposed between the first adhesive layer 105 and the second adhesive layer 203 during bonding. The first adhesive layer 105 and the second adhesive layer 203 are softer than the second electrode substrate 200 and the structure 103, and in the bonding process, the respective adhesive layers are deformed, mixed, or By compatibility, sufficient wetting, securing of a contact area, and an anchor effect can be expected.

  In addition, the second adhesive layer 203 formed on the second electrode substrate 200 is obtained by transferring a part of the first adhesive layer 105 formed on the upper surface of the structure 103, that is, the first adhesive layer The adhesive layer 105 and the second adhesive layer 203 are made of the same material and have substantially the same pattern shape. Thereby, the adhesiveness of the 1st adhesive bond layer 105 and the 2nd adhesive bond layer 203 can be improved. Furthermore, since it is possible to reduce the formation of an adhesive layer on the surfaces of the first electrode substrate 100 and the second electrode substrate 200 in a region other than the region overlapping with the structure body 103, the second electrode substrate 200 is entirely covered with the second electrode substrate 200. Compared with the structure in which the second adhesive layer 203 is formed, the display contrast is prevented from being lowered by applying a desired voltage to the electrophoretic ink during driving, and is lower in order to exhibit the desired display contrast. The driving voltage can be set.

  When a thermoplastic material is used as the first adhesive layer 105, the thermoplastic material is softened at a desired temperature (eg, 100 ° C.), and the higher the temperature, the better the wetting with the base material, and the adhesion, Adhesion is improved. In addition, some thermoplastic materials have tackiness (tackiness) even at room temperature, and such materials can provide adhesion and adhesion even at temperatures close to room temperature.

Further, when an ultraviolet curable material is used as the first adhesive layer 105, the ultraviolet curable material absorbs and cures a desired accumulated light amount (for example, 3000 mJ / cm ² ). For example, the first adhesive layer Immediately after forming 105 and the second adhesive layer 203, a part of the desired integrated light amount is irradiated in advance to make it a semi-cured state, and then the electrophoretic ink 106 is filled into the cell 104 and a bonding process is performed. The first adhesive layer 105 and the second electrode substrate 200, and the second adhesive layer 203 and the structure 103 are each improved in adhesion, and the bonding process is performed with a relatively small integrated light amount. Obtainable.

  Next, examples carried out in order to clarify the effects of the present invention will be described, but the present invention is not limited thereto.

(Example)
<Cell formation process>
After an acrylate resist film was bonded to the first electrode substrate (ITO-PET film) using a vacuum laminator, a structure having a honeycomb-shaped pattern was formed by a photoresist method.

<First adhesive layer forming step>
On a PET film with a release agent, a thermoplastic adhesive (hot melt resin) diluted with a solvent was applied using a comma roll to a thickness of 12 μm and then dried. Next, the PET film on which the thermoplastic adhesive layer is formed and the first electrode substrate on which the structure is formed are passed through a thermal laminator at 120 ° C. and peeled off in a heated state, whereby PET A part of the thermoplastic adhesive layer formed on the film was transferred to the upper surface of the structure. The film thickness of the thermoplastic adhesive layer formed on the upper surface of the structure was 6 to 8 μm.

<Contacting step, second adhesive layer forming step>
After the second electrode substrate is brought into contact with the upper surface of the structure having the thermoplastic adhesive layer formed on the surface, the second electrode substrate is passed through a thermal laminator at 120 ° C. and peeled off in a heated state to thereby remove the upper surface of the structure. A part of the thermoplastic adhesive layer formed on was transferred to the surface of the second electrode substrate. The film thickness of the thermoplastic adhesive layer formed on the upper surface of the structure was 3 to 6 μm, and the film thickness of the thermoplastic adhesive layer formed on the surface of the second electrode substrate was 1 to 4 μm.

<Electrophoretic ink filling process>
After the thermoplastic adhesive formed on the upper surface of the structure and the second electrode substrate is cooled, the electrophoretic ink (white particles (lipophilic surface-treated titanium oxide) is applied to the first electrode substrate using a die coater. , Negatively charged), black particles (acrylic particles colored with carbon black (positively charged), ink composed of normal dodecane (boiling point 216 ° C.)) to apply electrophoretic ink to the cell composed of the structure. Filled.

  Next, a main seal portion was formed on the outer periphery of the portion to which the electrophoretic ink was applied (cell forming portion) using an ultraviolet curable adhesive.

<Lamination process>
After aligning the first electrode substrate and the second electrode substrate coated with the electrophoretic ink so that the first adhesive layer and the second adhesive layer are combined, they are bonded through a thermal laminator, An electrophoretic display panel was produced by irradiating the main seal part formed on the outer periphery of the cell forming part with ultraviolet rays to cure the ultraviolet curable adhesive.

  Next, a comparative example will be described.

(Comparative example)
<Cell formation process>
After a 50 μm thick acrylate resist film was bonded to the first electrode substrate (ITO-PET film) using a vacuum laminator, a structure was formed by a photoresist method.

<First adhesive layer forming step>
On a PET film with a release agent, a thermoplastic adhesive (hot melt resin) diluted with a solvent was applied using a comma roll to a thickness of 12 μm and then dried. Next, the PET film on which the thermoplastic adhesive layer is formed and the first electrode substrate on which the structure is formed are passed through a thermal laminator at 120 ° C. and peeled off in a heated state, whereby PET A part of the thermoplastic adhesive layer formed on the film was transferred to the upper surface of the structure. The film thickness of the thermoplastic adhesive layer formed on the upper surface of the structure was 6 to 8 μm.

<Electrophoretic ink filling process>
After cooling the thermoplastic adhesive formed on the upper surface of the structure and the second electrode substrate, by applying electrophoretic ink (same as the example) to the first electrode substrate using a die coater, The cell made of the structure was filled with electrophoretic ink.

  Next, a main seal portion was formed on the outer periphery of the portion to which the electrophoretic ink was applied (cell forming portion) using an ultraviolet curable adhesive.

<Lamination process>
The first electrode substrate coated with the electrophoretic ink and the second electrode substrate are bonded again through a thermal laminator, and then the main seal portion formed on the outer periphery of the cell forming portion is irradiated with ultraviolet rays to be cured by ultraviolet rays. An electrophoretic display panel was produced by curing the mold adhesive.

  That is, the comparative example is different from the above-described example in that a thermoplastic adhesive layer is formed only on the upper surface of the structure (no adhesive layer is formed on the second electrode substrate).

(Reference example)
<Cell formation process>
After an acrylate resist film was bonded to the first electrode substrate (ITO-PET film) using a vacuum laminator, a structure having a honeycomb-shaped pattern was formed by a photoresist method.

<First adhesive layer forming step>
On a PET film with a release agent, a thermoplastic adhesive (hot melt resin) diluted with a solvent was applied using a comma roll to a thickness of 12 μm and then dried. Next, the PET film on which the thermoplastic adhesive layer is formed and the first electrode substrate on which the structure is formed are passed through a thermal laminator at 120 ° C. and peeled off in a heated state, whereby PET A part of the thermoplastic adhesive layer formed on the film was transferred to the upper surface of the structure. The film thickness of the thermoplastic adhesive layer formed on the upper surface of the structure was 6 to 8 μm.

<Second adhesive layer forming step>
The thermoplastic adhesive diluted with the solvent was applied and dried on a second electrode substrate (ITO-PET film) using a spin coater so that the film thickness after drying was 1 μm.

<Electrophoretic ink filling process>
After cooling the thermoplastic adhesive formed on the upper surface of the structure and the second electrode substrate, the first electrode substrate is electrophoresed with a dye coater (white particles (lipophilic surface-treated titanium oxide). , Negatively charged), black particles (acrylic particles colored with carbon black (positively charged), ink composed of normal dodecane (boiling point 216 ° C.)) to apply electrophoretic ink to the cell composed of the structure. Filled.

  Next, a main seal portion was formed on the outer periphery of the portion to which the electrophoretic ink was applied (cell forming portion) using an ultraviolet curable adhesive.

<Lamination process>
After aligning the first electrode substrate and the second electrode substrate coated with the electrophoretic ink so that the first adhesive layer and the second adhesive layer are combined, they are bonded through a thermal laminator, An electrophoretic display panel was produced by irradiating the main seal part formed on the outer periphery of the cell forming part with ultraviolet rays to cure the ultraviolet curable adhesive.

  That is, the reference example is different from the above example in that the second adhesive layer is formed on the entire surface of the second electrode substrate.

(Evaluation)
The electrophoretic panels produced in the steps of Examples, Comparative Examples, and Reference Examples were each tested by the following test methods to determine whether they were good or bad.

(Evaluation 1)
<Reflectance measurement>
The reflectance was measured using a spectrocolorimeter SC-T (P), manufactured by Suga Test Instruments Co., Ltd. The measurement conditions were set as follows.

Optical conditions: Diffuse illumination 8 ° light reception d8 method (* excluding regular reflection)
Light source: 12V / 50W halogen lamp Color measurement condition: D65 10 ° field of view Measurement area: φ15
Operation: Measured after standing 100 times on a desk in parallel with the tabletop and driving 100 times.

<Judgment method>
Based on the contrast value (= black reflectance / white reflectance), determination was made as follows.
○: Good display (contrast 10 or more)
Δ: operation but not good display (contrast 10-2)
×: Almost no operation (contrast 2 or less)

(Evaluation 2)
<Adhesiveness>
For the measurement of adhesion, JIS K6854 “180 ° T-type peel test” was performed using a sample obtained by cutting a part of an electrophoresis panel with a width of 25 mm and bending the opposing substrate 90 degrees outward at one end. It was performed according to the conditions.

<Judgment method>
Based on adhesive force and visual observation, it determined as follows.
○: The entire surface is in good contact (adhesive strength of 0.5 N / 25 mm or more, and there are traces of adhesion on the entire surface)
Δ: Adhesive strength is weak but in close contact (adhesive strength 0.5 N / 25 mm or less)
×: Not in close contact (adhesion cannot be measured, and there is a large break in the trace of the bonded part)

(Evaluation 3)
<Particle movement suppression>
The movement of the particles was suppressed by continuously driving and displaying 10,000 times or more in a state where the electrophoretic panel was set perpendicular to the direction of gravity.

<Judgment method>
Whether sedimentation was observed in the display part was determined as follows based on the result of visual observation.
○: No settling is observed in the entire display area.
Δ: Sedimentation is observed in part of the display.
X: Sedimentation is seen in the whole area in a display part. Some parts cannot be displayed.

  The results of the evaluations 1 to 3 are shown in Table 1.

  From Table 1, the example in which the adhesive layer is formed on both the upper surface of the structure formed on the first electrode substrate and the second electrode substrate is the structure formed on the first electrode substrate. It was found that a higher adhesive force was obtained than in the comparative example in which the adhesive layer was formed only on the upper surface of the film. Further, in the electrophoretic display device in which the adhesive layer is formed only on the upper surface of the structure formed on the first electrode substrate as in the comparative example, there is a gap between the structure and the electrode substrate due to insufficient adhesion. In other words, particle movement did not occur in the examples.

  Furthermore, when Examples and Reference Examples were compared, differences in contrast values were observed, although no difference was observed in the evaluation of adhesive force and particle movement. In the embodiment, the second adhesive layer that is substantially the same as the pattern shape of the upper surface of the structure is formed on the second electrode substrate, whereas in the reference example, the second adhesive layer is the second adhesive layer. This is considered due to the fact that the second adhesive layer is formed on the entire surface of the electrode substrate. That is, in the reference example, the display property is deteriorated because the second adhesive layer covers the electrode surface, whereas in the example, the second adhesive layer is applied only to a portion corresponding to the structure. Therefore, it can be said that good display can be maintained without degrading the display property.

DESCRIPTION OF SYMBOLS 100 1st electrode substrate 101 1st base material 102 1st electrode layer 103 Structure 104 Cell 105 1st adhesive layer 106 Electrophoretic ink 200 2nd electrode substrate 201 2nd base material 202 2nd Electrode layer 203 Second adhesive layer 300 Base material 302 Adhesive

Claims (3)

Forming a plurality of cells formed of an insulating structure standing on the first electrode substrate;
Forming a first adhesive layer on the upper surface of the structure;
Contacting a second electrode substrate with the upper surface of the structure on which the first adhesive layer is formed;
By peeling the second electrode substrate from the upper surface of the structure, a part of the first adhesive layer formed on the upper surface of the structure is transferred to the surface of the second electrode substrate, Forming a second adhesive layer on the surface of the second electrode substrate;
Filling the plurality of cells with electrophoretic ink;
The first electrode substrate and the second electrode substrate are disposed opposite to each other, and the first adhesive layer and the second adhesive layer are adhered to each other, whereby the first electrode substrate and the second electrode substrate are bonded to each other. Bonding the electrode substrate to the electrophoretic display device.   The step of forming the first adhesive layer on the upper surface of the structure body is performed by bringing the base material having the adhesive layer formed on the surface into contact with the upper surface of the structure body and then peeling it from the upper surface of the structure body. 2. A part of the adhesive layer formed on the substrate surface is transferred to the upper surface of the structure to form the first adhesive layer on the upper surface of the structure. A method for producing the electrophoretic display device according to claim.   In the step of bringing the first adhesive layer in the step of filling the plurality of cells with electrophoretic ink into contact with the upper surface of the structure on which the first adhesive layer is formed. The method for manufacturing an electrophoretic display device according to claim 1, wherein the first adhesive layer is hardened.

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