JP2002148662A - Display device and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophoretic display device which has high durability and by which high definition display is possible. SOLUTION: A first barrier rib 5a and a second barrier rib 5b are formed from the side of a first substrate 1 and the side of a second substrate 2, respectively, and stuck to each other. By adopting such a structure extremely fine barrier ribs can be easily formed and the display device which has high durability and by which high definition display is possible can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a display device which performs display by moving electrophoretic particles by an electric field, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, with the development of information equipment, the demand for low power consumption and thin display devices has been increasing, and research and development of display devices meeting these demands have been actively conducted. Among them, a liquid crystal display device that performs display by electrically controlling the arrangement of liquid crystal molecules and changing the optical characteristics of the liquid crystal,
Active developments have been made and commercialized as display devices that can meet the above demands. However, in the liquid crystal display device, the difficulty in seeing characters on the screen due to the angle at which the screen is viewed or the reflected light, and the burden on the sight caused by flickering and low luminance of the light source have not yet been sufficiently solved. For this reason, research on a display device with a small burden on vision has been actively conducted.

[0003] In view of such a demand for low power consumption and reduction of burden on eyes, a reflection type display device is expected.
One of them is Harold Di Lee
D. An electrophoretic display device invented by Lees et al. (US Pat. No. 3,612,758) is known.

FIG. 5 is a conceptual diagram showing a cross section of a conventional electrophoretic display device. 1 is a first substrate, 2 is a second substrate, 3 is a first electrode, 4 is a second electrode, 5 is a partition, 6 is an adhesive layer, 7 is an electrophoretic particle, 8 is a liquid dispersion medium, 9 is a pixel area, Reference numeral 10 denotes a display device.

This apparatus comprises a first substrate 1 and a second substrate 2 which are disposed opposite each other and at least one of which is a transparent substrate, and a partition wall 5 for forming a plurality of small sections between the substrates.
And a dispersion system in which the electrophoretic particles 7 are dispersed in a liquid dispersion medium 8 sealed in the small section, and a first electrode 3 in which at least one of which applies a voltage to the dispersion system is a pair of transparent electrodes. And the second electrode 4. In this device, it is necessary that at least the substrate and the electrodes on the observer side where the observer observes the display device are transparent.

In driving the display device, a voltage is applied to the electrodes 3 and 4 to form an electric field in the liquid dispersion medium 8 and the electrophoretic particles 7 are formed.
This is performed by attracting the electrophoretic particles 7 to any one of the electrodes according to the electrical polarity of the electrophoretic particles.

[0007] The display of the display device is performed by using the color of the electrophoretic particles 7 and the color of the liquid dispersion medium 8 in which a coloring pigment having a different color from the electrophoretic particles 7 is dissolved. That is, when a voltage is applied between the electrodes and the electrophoretic particles 7 move to the side opposite to the observer side, the observer does not recognize the color of the electrophoretic particles 7 and the color of the liquid dispersion medium 8 changes. To be observed. on the other hand,
When the voltage applied between the electrodes is reversed and the electrophoretic particles 7 are moved to the observer side, the observer is notified of the electrophoretic particles 7.
Is recognized, and binary display can be performed by the colors of the electrophoretic particles 7 and the liquid dispersion medium 8.

As a manufacturing method, for example, there is the following method. First, the first electrode 3 is formed on the first substrate 1. On this, a partition wall 5 which keeps a constant interval between the first substrate 1 and the second substrate 2 and divides each pixel region 9 is formed.
Then, the pixel region 9 is filled with a dispersion system composed of the electrophoretic particles 7 and the liquid dispersion medium 8, and the second substrate 2 on which the second electrode 4 is formed is attached to manufacture a display device.

[0009]

However, in order to increase the definition of the electrophoretic display device, the area of the pixel region 9 is reduced, and the partition walls 5 separating the pixel regions 9 are formed with an extremely small width. Need to be formed.

At this time, if the height of the partition is reduced, the width of the partition can be easily reduced. However, when the partition is lowered, there is a problem that the display contrast is reduced. This is because, in the electrophoretic display device, when a voltage is applied to both electrodes and the electrophoretic particles are drawn toward the observer as described above, the observer sees the color of the electrophoretic particles, If the electrophoretic particles are drawn to the side opposite to the observer, the observer will see the color of the liquid dispersion medium, but if the partition walls are low, the color of the electrophoretic particles will also be seen through the liquid dispersion medium. Because it will be visible. In this way, the difference between the two values of the binary display is reduced, and the contrast is reduced.

As described above, in the electrophoretic display device, there is a limitation that the height of the partition walls cannot be reduced in order to maintain the display contrast. Therefore, in order to increase the definition of the electrophoretic display device, a high aspect ratio (height / height ratio) is required.
Width).

However, there is a problem that a process of forming a pattern having a high aspect ratio is very difficult. In addition, partition walls having a high aspect ratio have problems such that they are easily collapsed structurally, and are easily peeled off due to the small area of the contact portion between the partition wall and the substrate.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and enables a partition having fineness, a high aspect ratio, and hard to collapse or peel off to be easily formed, and has high durability. An object is to provide a high-definition electrophoretic display device.

[0014]

According to a method of manufacturing a display device of the present invention, a first substrate and a second substrate, which are disposed opposite each other and at least one of which is a pair of transparent substrates, and a plurality of small sections are provided between the substrates. And a dispersion system in which electrophoretic particles are dispersed in a liquid dispersion medium sealed in the small area, and a first electrode and a second electrode which are a pair of electrodes for applying a voltage to the dispersion system. A first electrode and a second electrode.
A method for manufacturing a display device for performing display by moving electrophoretic particles by an electric field generated by a voltage applied between electrodes, comprising: forming a first partition on a first substrate; The method is characterized by including at least a step of forming a second partition and a step of fixing the first substrate and the second substrate by bonding with the first partition and the second partition facing each other.

In the present invention, the first partition and the second partition are provided.
The partition has a width of 5 to 100 μm and a height of 5 to 100 μm.
m, each having an aspect ratio of 0.1 to 10, the first partition and the second partition are formed using a photosensitive resin, and at least one of the first partition and the second partition. Is formed using a swellable material as a preferred embodiment.

Further, the display device of the present invention comprises a first substrate and a second substrate which are arranged opposite to each other and at least one of which is a transparent substrate, and a partition for forming a plurality of small sections between the substrates. A dispersion system in which the electrophoretic particles are dispersed in a liquid dispersion medium sealed in the small section, and a first electrode and a second electrode which are a pair of electrodes for applying a voltage to the dispersion system. A display device for performing display by moving electrophoretic particles by an electric field generated by a voltage applied between a first electrode and a second electrode, wherein the display device is a display device according to any one of claims 1 to 4. Characterized in that it is manufactured using the manufacturing method of (1).

[0017]

Embodiments of the present invention will be specifically described below with reference to the drawings, but the present invention is not limited to these embodiments.

FIG. 4 is a schematic diagram showing a cross section of the display device of the present invention. 1 is a first substrate, 2 is a second substrate, 3 is a first electrode, 4 is a second electrode, 5a and 5b are first and second partitions having a structure characteristic of the present invention, and 6 is an adhesive layer. , 7 represent electrophoretic particles, 8 represents a liquid dispersion medium, and 9 represents a pixel region.

The first partition 5a is formed from the first substrate 1 side, and the second partition 5b is formed from the second substrate 2 side. By adopting such a structure, if the aspect ratio of the partition in the final product is the same, the partition on the first substrate side and the first partition on the first substrate side can be compared with a conventional structure in which the partition wall is formed in a single layer from either substrate side. The aspect ratio (height / width) of the partition walls formed on each of the two substrates can be reduced. Accordingly, extremely fine partition walls can be easily formed, and a display device capable of high-definition display can be provided. In the case where a flexible material is used for the substrate and the partition forming the display device, when the substrate is bent, a stress generated due to a difference in curvature between the two substrates is caused by the first partition and the second partition. The displacement is alleviated, and the load on the partition and the contact portion between the partition and the substrate is greatly reduced. Therefore, problems such as collapse and separation of the partition hardly occur. Furthermore, if the same durability is required, a material having lower strength than the conventional one can be used, so that the degree of freedom in selecting the material of the partition wall is increased. Note that the first partition 5a and the second partition 5b may or may not be bonded.

A transparent material is used for at least one of the first substrate 1 and the second substrate 2, and a first electrode 3 and a second electrode 4 are formed on one surface of each substrate. At this time, the side on which the dispersion medium in the display device is made observable using a transparent material is the observer side. In the following, for convenience of explanation, the second substrate 2 is formed using a transparent material. This shows an embodiment in which the side of the two substrates 2 is set to the observer side. Note that the first substrate 1,
If a display device is manufactured by using a transparent material for all of the second substrate 2, the first electrode 3, and the second electrode 4, the two-sided image is obtained by reversing a binary image and reversing the left and right images. Is obtained.

In the following description, the first electrode on which the first electrode is formed will be described.
The substrate is referred to as a first electrode plate, and the second substrate on which the second electrode is formed is referred to as a second electrode plate.

FIGS. 1 to 3 are process diagrams showing an embodiment of the method for manufacturing a display device according to the present invention, and the embodiment of the method for manufacturing a display device according to the present invention will be specifically described with reference to FIGS. . 6a and 6b are adhesive layers formed on the first electrode plate and the second electrode plate, respectively. 10 is a display device, 11
Denotes a pressing flat plate, 12 denotes a heater, and 13 denotes a vacuum container.

Step 1- (a) On the first substrate 1, a first electrode 3, a first partition 5a, an adhesive layer 6
a is formed.

First, a thin film made of a conductive material is formed on the first substrate 1, and the conductive film is patterned according to the design of the display device to form the first electrode 3.

The material of the first substrate 1 is a material having high heat resistance, for example, PET (polyethylene terephthalate),
A resin film such as PES (polyethersulfone) or polyimide, or an inorganic material such as glass or quartz can be used.

The thickness of the first substrate 1 is appropriately determined depending on the design in accordance with the application, but is preferably about 10 to 1000 μm in order to provide flexibility to the display device. In this case, it is preferable to use a flexible material, for example, a plastic such as PET.

As the conductive material as the material of the first electrode 3, a metal material, a metal oxide, or the like can be used.
1, Au, Pt, Ag, Ni, Ti, Cr, ITO
(Indium tin oxide), ZnO, SnO ₂
Etc. Also, TiC or the like can be used.

The conductive material is deposited by vacuum deposition such as ion plating, sputtering, or CV.
Chemical methods such as D (Chemical Vapor Deposition) can be used. The patterning of the conductive film can be performed by a mask method such as photoetching or a widely used method such as lithography.

Although not shown in the figure, the first electrode 3
May be appropriately formed. An acrylic resin, a polyimide resin, or the like can be used as a material of the insulating layer.

Next, a first partition 5a is formed on the first electrode plate. For the first partition wall 5a and the second partition wall 5b formed in a process to be described later, a photosensitive resin that can be easily and precisely patterned is preferably used, and the method will be described here.

A photosensitive resin film is formed on the first electrode plate, and the photosensitive resin film is patterned to form a first partition 5a.

As the photosensitive resin, a photoresist based on a cyclized rubber, a polycinnamic acid-based or quinonediazide-based photoresist can be used. In particular, it is preferable to use a photosensitive resin for a thick film in order to form a partition having a sufficient height. For example, there is a photosensitive resin “PMER-NCA3000” manufactured by Tokyo Ohka Kogyo Co., Ltd.

For forming the photosensitive resin, there are methods such as spin coating and roll coating.

The patterning of the photosensitive resin film can be performed by a known method such as lithography.

The dimensions of the first partition wall 5a vary depending on the size of the display device, but are usually preferably selected in the range of about 5 to 100 μm in width, 5 to 100 μm in height, and about 0.1 to 10 in the aspect ratio. .

When the adhesion between the first electrode plate and the first partition 5a is not good, an adhesive layer (not shown) may be formed between them as appropriate. As this adhesive, epoxy resin,
Phenol resin, vinyl resin, etc. can be used.

In order to use the liquid dispersion medium 8 later as a flow path for injecting it into each pixel region 9, a concave portion (not shown) at the top of the first partition wall 5 a for communicating the adjacent pixel region 9. Is provided. The recess can be formed by dry etching or the like. The concave portion may be provided later on the second partition 5b. When the concave portion is provided on the top of the second partition 5b, the concave portion is not necessarily provided on the top of the first partition 5a. It does not matter.

It is preferable that the size of the flow path is set to such a size that the electrophoretic particles 7 cannot pass through. For example, if the particle size of the electrophoretic particles 7 is about 5 μm, the flow channel may be formed with a depth of about 3 μm and a width of about 3 μm.

An adhesive layer 6a is formed on the first electrode plate so as to surround the outer edge.

For the adhesive layer 6a, a hot melt adhesive is preferably used because of the convenience of the subsequent steps.

Step 1- (b) The electrophoretic particles 7 are evenly distributed to the pixel regions 9 separated by the first partition walls 5a.

The material of the electrophoretic particles 7 is typically titanium oxide (white). In addition to well-known colloidal particles, various organic or inorganic pigments, dyes, metal powders, fine powders such as glass or resin, Those to which a coloring agent is added, for example, a mixture of polystyrene and carbon, and the like can be appropriately used. In addition, these may be used alone, or two or more of them may be used in combination, or a charge control agent or the like may be used as needed.

Step 1- (c) Second partition 5b formed on the second electrode plate manufactured in the same manner as the first electrode plate manufactured in step 1- (a)
And the first partition 5a.

The material that can be used for the second substrate 2 is the same as that of the first substrate, but in addition to this, plastic such as PET is preferably used in order to have a light transmitting property.

The thickness of the second substrate 2 is the same as that of the first substrate 1,
It is determined as appropriate depending on the design according to the application, but preferably 10 to 1000 when giving flexibility to the display device.
It is about μm. In this case, it is preferable to use a flexible material, for example, a plastic such as PET.

For the second electrode 4, a transparent conductive material such as a metal oxide can be used. For example, a material similar to that described in the description of the first electrode 3 such as ITO can be preferably used. In addition, a transparent conductive film can be formed by forming a film of Au, Ag, or another metal at about 200 ° or less, and this can also be used as the second electrode 4. As the film forming method and the patterning method, the same methods as those described in the description of the first electrode 3 can be preferably used.

The materials that can be used for the second partition 5b and the adhesive layer 6b are the same as those described above for the first partition 5a and the adhesive layer 6a. When the adhesion between the second electrode plate and the second partition 5b is not good, an adhesive layer (not shown) may be provided between them as appropriate. As the adhesive, the first
As in the case of the electrode plate and the first partition 5a, an epoxy resin, a phenol resin, a vinyl resin, or the like can be used.

Although not shown in the figure, the second electrode 4
May be appropriately formed. An acrylic resin, a polyimide resin, or the like can be used as a material of the insulating layer.

Step 1- (d) The display device formed up to the step 1- (c) is placed in the gas phase portion of the vacuum vessel 13 containing the necessary and sufficient amount of the liquid dispersion medium 8. Thereafter, the gas phase portion inside the vacuum vessel 13 is evacuated to vacuum, and the display device is submerged in the liquid dispersion medium 8. When the display device is immersed in the liquid, the pressure in the vacuum vessel 13 is increased to the atmospheric pressure, and the liquid dispersion medium 8 is injected into the display device. When the liquid dispersion medium 8 is sufficiently injected into all the pixel regions 9, the adhesive layer 6a and the adhesive layer 6b are thermally fused to encapsulate the dispersion.

In the present embodiment, as an example of the method of enclosing the dispersion system, the pressing flat plate 11 having the heater 12 is used.
Is pressed against the upper surface of the display device, and while heating the adhesive layers 6a and 6b using the heater 12, the excess liquid dispersion medium 8 is pushed out through the flow path while the adhesive layers 6a and 6b are pushed out.
Although the method for performing heat fusion bonding with the substrate is shown in the drawings, the method for heating the adhesive layer in the present invention is not limited to heat conduction of heat generated by the heater, and may use electromagnetic waves such as heat transfer and infrared rays. . Also, the pressing method is not limited to the method using the flat plate shown here, and for example, a method of sequentially pressing from the end or the center using an object having a roller shape or another shape may be used.

As the material of the liquid dispersion medium 8, besides water, alcohols, hydrocarbons, halogenated hydrocarbons and the like, various kinds of natural or synthetic oils and the like can be used. Dispersed materials can also be used. Specifically, for example, a solution obtained by dissolving a surfactant in a mixture of hexylbenzene and oil blue, or silicone oil can be used.

Step 1- (e) According to the above step 1- (d), the display device in which the dispersion system is sealed in each pixel region 9 is taken out of the vacuum container 13.

Step 1- (f) An electric circuit is connected to the display device 10. As a result, display can be performed.

In the above embodiment, the first partition 5a
Although the method of forming the second partition wall 5b with a photosensitive resin has been described, there is also a method of forming the second partition wall 5b with a swellable material that is a material that swells with the liquid dispersion medium 8.

When a swellable material is used for at least one of the first partition and the second partition, the partition using the swellable material swells after injecting the liquid dispersion medium 8 to substantially cover each pixel region 9. Can be sealed. Therefore, since the electrophoretic particles 7 and the liquid dispersion medium 8 do not move between the adjacent pixel regions 9, it is possible to prevent a problem such as deterioration of display quality due to non-uniform particle concentration distribution. In particular, when imparting flexibility to the display device, at least one of the first partition wall 5a and the second partition wall 5b has a swelling property in order to obtain a partition wall in which migration of the electrophoretic particles is less likely to occur and a partition wall resistant to bending. Preferably, it is made of a material.

In this case, it is not necessary to provide the flow path. However, unlike the step 1- (c) in which the first partition 5a and the second partition 5b are bonded, the adhesive layers 6a and 6b are bonded. Then, the process proceeds to the next step 1- (d) in the state where the adhesive layer 6a,
6b is not formed so as to completely surround the outer edge, and at least two portions are left without adhering portions so that each pixel region 9 communicates with the outside in order to secure a flow path used for injecting and discharging the liquid dispersion medium 8. Form.

As the swellable material, synthetic rubbers such as styrene-butadiene-based, isoprene-based, ethylene-propylene-based, acrylonitrile-butadiene-based, and chloroprene-based rubbers and natural rubbers can be used. Specifically, for example, there is silicone rubber.

When such a swellable material is used, the swellable material is not only square or slit-shaped but also square or rectangular, and is regularly or irregularly stamped or drilled. The swelling ratio can be increased by appropriately providing through holes by means.

As a method of obtaining a partition having a desired shape using a swellable material, first, a partition is formed in an approximate shape by screen printing or spraying, and the size of the partition in a state where the partition is swollen is further determined. In order to obtain a proper shape, there is a method of precisely molding a desired shape by a hot press or the like.

Further, in the above-described embodiment, an example has been described in which the electrophoretic particles 7 and the liquid dispersion medium 8 are put into the display device in separate steps, but the electrophoretic particles 7 and the liquid dispersion medium 8 are mixed in advance. There is also a manufacturing method in which a dispersion system is set in advance and the dispersion system is injected into a display device before the first partition 5a and the second partition 5b are overlapped. Also in this case, the above-mentioned flow path need not be provided.

Further, in the above-described embodiment, an example in which the first electrode 3 is formed on the first substrate 1 and the second electrode 4 is formed on the second substrate 2 has been described, but the first electrode 3 and the second electrode 3 are formed. It is also possible to manufacture a display device by forming 4 on the first substrate 1 side.

In this case, instead of the above step 1- (a),
The first substrate is manufactured by the following method. This will be described with reference to FIG. 3A, which is a process diagram illustrating a third embodiment of the display device manufacturing method according to the present invention, which will be described later. 14a
And 14b are insulating layers.

The first electrode 3 is formed on the first substrate 1 by the process 1-
It is formed in the same manner as (a), and is covered with an insulating layer 14a. The second electrode 4 is formed on the insulating layer 14a in the same manner as the first electrode 3. Further, the upper surface is covered with an insulating layer 14b, and a first partition wall 5a and an adhesive layer 6a are formed thereon in the same manner as in the step 1- (a).

In this case, since no electrode is required on the side of the second substrate 2, the step of manufacturing the second electrode 4 in the method of manufacturing the second electrode plate described in the above step 1- (c) is omitted. The second substrate side may be manufactured by omitting it.

In this case, the display method of the display device is as follows.
It has a slightly different property from the above display method. That is, by designing the area ratio between the first electrode 3 and the second electrode 4 to be as large as possible, when the electrophoretic particles 7 are attracted to the electrode having the larger area by applying a voltage, the electrophoresis is performed. When the color of the particles 7 is observed and the electrophoretic particles 7 are attracted to the electrode having the smaller area by applying a voltage, the color of the liquid dispersion medium 8 or the color of the inner surface on the substrate side opposite to the observer side is observed. Then, display is performed by these binary displays.

Even when the color of the inner surface on the substrate side opposite to the observer side is used, if the height of the partition walls is low, the concentration of the electrophoretic particles cannot be sufficiently obtained, and the contrast is lowered. . In addition, the height of the partition and the state of convection of the liquid dispersion medium are closely related, and therefore, the height of the partition is determined by the correlation between the diameter of the electrophoretic particles, the charge ratio, the viscosity of the liquid dispersion medium, and the like. The width in which the height of the partition can be changed is preferably as large as possible. Therefore, also in this case, the height of the partition wall is required to some extent, and the present invention is effective.

[0067]

(Embodiment 1) This embodiment will be described with reference to FIG. 1 which is a process chart showing a first embodiment of a method of manufacturing a display device according to the present invention.

Step 1- (a) An IT is formed on the upper surface of the first substrate 1 made of PET having a thickness of 100 μm.
O was deposited to a thickness of 100 nm by sputtering, and was patterned by photolithography and wet etching to form the first electrode 3 to produce a first electrode plate.

On the first electrode plate, a photosensitive resin “PMER-NCA3000” manufactured by Tokyo Ohka Kogyo Co., Ltd. is formed into a film having a thickness of 30 μm by spin coating. The photosensitive resin was removed vertically and horizontally at intervals of 10 μm. In this manner, the first partition 5 having a height of 30 μm and a width of 10 μm is formed in a lattice pattern surrounding a 250 μm square area serving as the pixel area 9.
a was formed.

Although not shown in the figure, the first partition 5a
6 μm deep and 20 μm wide
Was formed by dry etching.

An adhesive layer 6a was formed around the first partition wall 5a using a silicone adhesive.

Step 1- (b) Next, the electrophoretic particles 7 were evenly distributed to each pixel region 9.
As the electrophoretic particles 7, titanium oxide (white) having an average particle size of 5 μm was used.

Step 1- (c) A second electrode plate, a second partition wall 5b thereon, and an adhesive layer 6b were formed in the same manner as in the above-described step 1- (a). Then, the first partition 5a and the second partition 5b were brought into contact with each other.

Step 1- (d) The display device formed up to the above-mentioned step 1- (c) is placed in the gas phase portion of the vacuum vessel 13 containing the necessary and sufficient amount of the liquid dispersion medium 8. As the liquid dispersion medium 8, a solution obtained by dissolving a surfactant in a dark blue dye consisting of hexylbenzene and oil blue was used. Thereafter, the gas phase portion inside the vacuum vessel 13 is evacuated to vacuum, and the display device is submerged in the liquid dispersion medium 8. When the display device is immersed in the liquid, the pressure in the vacuum vessel 13 is gradually increased to the atmospheric pressure, and the liquid dispersion medium 8 is injected into the display device.

All the pixel regions 9 have a sufficient liquid dispersion medium 8
When the pressure is injected, the heater 12 is heated while slowly pressing the pressing flat plate 11 having the heater 12 from the upper surface of the display device, and while the excess liquid dispersion medium 8 is pushed out through the flow path, the adhesive layer 6a and the adhesive layer 6b by heat fusion bonding.

Step 1- (e) The display device in which the dispersion system was completely sealed in all the pixel regions 9 was taken out of the vacuum vessel 13.

Step 1- (f) An electric circuit was connected to the display device 10. Thus, display can be performed.

The display was performed by applying a voltage between the electrodes. The applied voltage was ± 100V. Since the white electrophoretic particles 7 used in the present example were positively charged in the blue liquid dispersion medium 8, they were moved to the negatively applied electrode by the voltage application. Accordingly, when the second electrode 4 is used as a positive electrode and the first electrode is used as a negative electrode, the white electrophoretic particles 7 move on the first electrode, and pass through the second electrode 4 from the upper surface of the second substrate 2. The observed display surface was blue. On the other hand, when the polarity of the electrodes is reversed and the first electrode 3 is used as the positive electrode and the second electrode 4 is used as the negative electrode, the white electrophoretic particles 7 move on the second electrode. Thus, the display surface observed through the second electrode 4 became white.

At this time, a value with a display contrast of 4 and a response speed of about 100 msec was obtained.

In the display device 10 of this embodiment, the first partition 5
By combining a with the second partition 5b, a partition having a height of 60 μm and a width of 10 μm could be formed. It is very difficult to form such a high aspect ratio partition by a conventional method, and it has a problem that it is structurally easily collapsed and easily peeled off. In addition, high-definition display can be easily performed as compared with the related art, and problems such as collapse and separation of the partition walls are less likely to occur.

(Embodiment 2) This embodiment will be described with reference to FIG. 2 which is a process chart showing a second embodiment of the method for manufacturing a display device of the present invention.

Step 2- (a) An IT is formed on the upper surface of the first substrate 1 made of PET having a thickness of 100 μm.
O was deposited to a thickness of 100 nm by sputtering, and was patterned by photolithography and wet etching to form the first electrode 3 to produce a first electrode plate.

A silicone rubber sheet having a large number of through holes is formed on the first electrode plate by a screen printing method, so that a grid pattern surrounding a 250 μm square area serving as a pixel area 9 has a height of 15 μm and a width of 15 μm. A first partition 5a of 15 μm was formed.

Then, an adhesive layer 6a was formed around the first partition wall 5a using a silicone adhesive.

Step 2- (b) Next, the electrophoretic particles 7 were evenly distributed to each pixel region 9.
As the electrophoretic particles 7, titanium oxide (white) having an average particle size of 5 μm was used.

Step 2- (c) A second electrode plate is formed by the same method as the manufacturing method shown in the above-described step 2- (a), and the second partition 5b thereon is formed in the same manner as in Example 1.
In the same manner as the method of forming the first partition wall 5a shown in Step 1- (a), a grid pattern surrounding a 250 μm square area serving as the pixel area 9 was formed with a height of 30 μm and a width of 15 μm. The adhesive layer 6b was formed in the same manner as in the step 2- (a).

Then, with the gap between the first electrode plate and the second electrode plate kept at 50 μm, the adhesive layers 6a and 6b were heat-sealed. Although not shown in the drawing, at this time, at least two portions of the adhesive layers 6a and 6b are left unadhered so that the pixel region communicates with the atmosphere in order to form a flow path serving as an injection port and an exhaust port. I left it.

Step 2- (d) The display device formed up to the above-mentioned step 2- (c) is placed in the gas-phase portion of the vacuum vessel 13 containing the necessary and sufficient amount of the liquid dispersion medium 8. As the liquid dispersion medium 8, a solution obtained by dissolving a surfactant in a dark blue dye consisting of hexylbenzene and oil blue was used. Thereafter, the gas phase portion inside the vacuum vessel 13 is evacuated to vacuum, and the display device is submerged in the liquid dispersion medium 8. When the display device is immersed in the liquid, the pressure in the vacuum vessel 13 is gradually increased to the atmospheric pressure, and the liquid dispersion medium 8 is injected into the display device.

All the pixel regions 9 have sufficient liquid dispersion medium 8
When the pressure is injected, the heater 12 is heated while slowly pressing the pressing flat plate 11 having the heater 12 from the upper surface of the display device, and while the excess liquid dispersion medium 8 is pushed out through the flow path, the adhesive layer 6a and the adhesive layer 6b by heat fusion bonding.

Step 2- (e) The display device in which the dispersion system was completely sealed in all the pixel regions 9 was taken out of the vacuum vessel 13.

Step 2- (f) An electric circuit was connected to the display device 10. Thus, display can be performed.

The display was performed by applying a voltage between the electrodes. The applied voltage was ± 100V. As in the first embodiment, the display contrast is 4, and the response speed is 100 msec.
A value of the order was obtained.

In the display device 10 of this embodiment, the first partition 5
By using a swellable material as a, each pixel region 9
Can be substantially sealed, so that the electrophoretic particles 7 and the liquid dispersion medium 8 do not move between the adjacent pixel regions 9, and the concentration distribution is less likely to be non-uniform. Further, when the substrate is bent, 2
The stress generated due to the difference in the curvatures of the substrates is reduced by the displacement of the overlapped partition wall surface and the role of the cushioning material because the first partition wall 5a has flexibility. The load on the contact portion between the substrate and the substrate is greatly reduced. Therefore, peeling, displacement, and collapse of the partition walls hardly occur.

(Embodiment 3) This embodiment will be described with reference to FIG. 3, which is a process chart showing a third embodiment of the method for manufacturing a display device of the present invention.

Step 3- (a) On the first substrate 1 in which a light scattering layer (not shown) is provided by spin coating on a PET having a thickness of 100 μm, an ITO film is formed to a thickness of 100 nm by sputtering, and a first electrode is formed. 3 was formed. An acrylic resin layer having a thickness of about 2 μm was formed on the first electrode 3 as the insulating layer 14a. Insulating layer 14a
The second electrode 4 is formed by sputtering TiC to 100
A film having a thickness of nm was formed, and was patterned in a line shape by photolithography and dry etching so as to have an aperture ratio of 70% in the pixel region. Thereby, the first
The second electrode 4 is formed so as to be shifted from the electrode 3 in the horizontal direction and the vertical direction with respect to the first substrate 1 and to have a region overlapping the first electrode 3 and the first substrate 1 in the horizontal direction. Was. Further, an acrylic resin layer was formed as the insulating layer 14b.

Step 3- (b) to Step 3- (f) The same as Step 1- (a) to Step 1- (f) in Example 1.

However, as the liquid dispersion medium 8, silicone oil was used. The electrophoretic particles 7 are composed of a mixture of polystyrene and carbon, are black, and have an average particle size of 6.
μm was used.

Since the black electrophoretic particles 7 used in this example were positively charged in the silicone oil, they moved onto the negative electrode by applying a voltage. Thereby, the second electrode 4
Is used as the positive electrode and the first electrode 3 is used as the negative electrode, the black electrophoretic particles 10 move on the first electrode 3 and observed through the transparent first electrode 3 with the black electrophoretic particles 7. The first substrate 1 having the light diffuse reflection layer is covered. The display surface viewed from the upper surface of the second substrate 2 was a black display.

When the polarity of the voltage applied to one electrode is inverted and the first electrode 3 is used as a positive electrode and the second electrode 4 is used as a negative electrode, the black electrophoretic particles 7 move on the dark black second electrode. Thus, the first substrate 1 having light reflectivity observed through the transparent first electrode 3 is exposed. The display surface viewed from the upper surface of the second substrate 2 was a white display.

When the display device 10 manufactured in this example was driven at a driving voltage of ± 100 V, the display contrast was 4, and the response speed was 30 msec or less.

In the display device of this embodiment, as in the first embodiment, by combining the first partition 5a and the second partition 5b, a partition having a height of 60 μm and a width of 10 μm can be formed.
The same effect as in Example 1 was obtained for the partition walls.

[0102]

As described above in detail, according to the method of manufacturing a display device of the present invention, it is possible to easily form a fine partition having a high aspect ratio and hardly causing collapse or peeling. An electrophoretic display device having high durability and high definition can be provided.

[Brief description of the drawings]

FIG. 1 is a process chart showing a first embodiment of a method of manufacturing a display device of the present invention.

FIG. 2 is a process chart showing a second embodiment of the method of manufacturing the display device of the present invention.

FIG. 3 is a process chart showing a third embodiment of the method of manufacturing the display device of the present invention.

FIG. 4 is a schematic view showing a cross section of the display device of the present invention.

FIG. 5 is a conceptual diagram showing a cross section of a conventional electrophoretic display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st board | substrate 2 2nd board | substrate 3 1st electrode 4 2nd electrode 5 Partition 5a 1st partition 5b 2nd partition 6,6a, 6b Adhesive layer 7 Electrophoretic particle 8 Liquid dispersion medium 9 Pixel area 10 Display device 11 Pressing Flat plate 12 Heater 13 Vacuum container 14a, 14b Insulating layer

Claims (5)

[Claims] 1. A first substrate and a second substrate which are arranged opposite to each other and at least one of which is a transparent substrate, a partition for forming a plurality of small sections between the substrates, and sealed in the small sections. And at least a first electrode and a second electrode, which are a pair of electrodes for applying a voltage to the dispersion system, in which the electrophoretic particles are dispersed in a liquid dispersion medium. A method of manufacturing a display device for displaying by moving electrophoretic particles by an electric field generated by a voltage applied between two electrodes, comprising: forming a first partition on a first substrate; Manufacturing a display device characterized by including at least a step of forming a second partition wall and a step of fixing the first substrate and the second substrate by bonding in an arrangement where the first partition wall and the second partition wall face each other. Method. 2. The first partition and the second partition have a width of 5 to 1
2. The method for manufacturing a display device according to claim 1, wherein each of the display devices is formed in a shape having a size of 00 μm, a height of 5 to 100 μm, and an aspect ratio of 0.1 to 10. 3. The method according to claim 1, wherein the first partition and the second partition are formed using a photosensitive resin. 4. The manufacturing method of a display device according to claim 1, wherein at least one of the first partition and the second partition is formed using a swellable material. Method. 5. A first substrate and a second substrate which are arranged opposite to each other and at least one of which is a transparent substrate, a partition for forming a plurality of small sections between the substrates, and sealed in the small sections. And at least a first electrode and a second electrode, which are a pair of electrodes for applying a voltage to the dispersion system, in which the electrophoretic particles are dispersed in a liquid dispersion medium. A display device that performs display by moving electrophoretic particles by an electric field generated by a voltage applied between two electrodes, and manufactured by using the manufacturing method according to claim 1. A display device characterized by being performed.