JP2003015166A - Electrophoretic display - Google Patents

Abstract

(57) [Problem] To provide a stable image in an electrophoretic display device by suppressing the movement of particles across partition walls, which occurs when the substrate is placed vertically or when a substrate is bent. SOLUTION: A pair of substrates, electrodes formed on the substrates, a dispersion medium filled between the substrates, charged electrophoretic particles dispersed in the dispersion medium, and another of the substrates formed on one of the substrates In an electrophoretic display device provided in contact with a substrate and having a partition for dividing the charged electrophoretic particles and the dispersion medium into small sections, the other substrate on which the partition is not formed has a side in contact with the partition. Electrophoretic display device having a flexible surface layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophoretic display device in which display is performed by moving electrophoretic particles between electrodes.

[0002]

2. Description of the Related Art In recent years, with the development of information equipment, the need for low power consumption and thin display devices has increased, and research and development of display devices meeting these needs have been actively conducted. Among them, the liquid crystal display device is capable of electrically controlling the alignment of liquid crystal molecules and changing the optical characteristics of the liquid crystal, and has been actively developed and commercialized as a display device that can meet the above needs.

Reflective display devices are expected from the viewpoint of low power consumption and reduction of burden on the eyes. One of them is
Harold D. An electrophoretic display device (U.S. Pat. No. 3,612,758) invented by Lees et al. Is known. In addition, an electrophoretic display device has been proposed in Japanese Patent Laid-Open No. 9-185087.

The electrophoretic display device will be described below. FIG. 4 is a sectional view showing an example of the structure of such an electrophoretic display device (an example in which particles move horizontally). The electrophoretic display device shown in FIG. 4 includes a pair of substrates 3a and 3b arranged with a predetermined gap therebetween, and the substrates 3a and 3b.
A dispersion medium 2 filled between a and 3b, charged electrophoretic particles 1 dispersed in the dispersion medium 2, a first electrode 4a and a second electrode 4b arranged along one substrate 3b, and The partition wall 7 is arranged so as to partition the gap between the substrates 3a and 3b into pixels. In this apparatus, since the charged electrophoretic particles 1 are charged in the positive polarity or the negative polarity (in FIG. 4, they are charged in the positive polarity), the electrode 4
Electrophoresis is performed on any of the electrodes 4a or 4b according to the polarity of the voltage applied to a and 4b, but since the regions where the charged electrophoretic particles 1 and the electrodes 4a and 4b are arranged are colored,
Images can be displayed on the entire display device.

FIG. 5 shows an example of an electrophoretic display device in which particles move vertically. In FIG. 5, an image can be displayed by coloring the dispersion medium 2 in a color different from that of the charged electrophoretic particles 1. In both of the electrophoretic display devices shown in FIGS. 4 and 5, the partition walls 5 keep the distance between the substrates constant.

Further, in such an electrophoretic display device, when there is a gap between the partition wall 7 and the substrate 3a, the electrophoretic particles move to the adjacent section beyond the partition wall, resulting in uneven density of the particles. Alternatively, when the display surface is installed in the vertical direction, the particles pass through the gap and uneven density of the particles occurs. The uneven density of these particles leads to defective display of images. In order to solve this problem, the partition wall 7 and the substrate 3a or the substrate 3b are adhered by an adhesive layer 8 (for example,
When a partition is formed on the substrate 3b, the other substrate 3
a) and the partition wall 7 are bonded), and it has been attempted to eliminate the gap in which the charged electrophoretic particles 1 move beyond the partition wall 7, and as a result, the partition wall 7 and the substrates 3a and 3b are divided into small sections. The room is completely closed.

[0007]

However, in the electric display device in which the partition wall is adhered to the substrate, when the display substrate is bent, bending stress is concentrated on the bonding portion between the partition wall and the substrate, and the partition wall is damaged, Alternatively, there is a problem that the adhesive portion is peeled off.

In order to solve this problem, Japanese Patent Laid-Open No. 1-1
JP-A-14828 describes an electrophoretic display device in which a partition wall made of a swelling material is used to swell the partition wall in a dispersion medium to seal a gap between the partition wall and an upper substrate. Further, in JP-A-1-142537, by pressing a partition wall made of an elastic member with an upper substrate,
An electrophoretic display device in which a gap between a partition wall and an upper substrate is sealed is described.

However, since both of the proposed barrier rib materials use synthetic rubber or natural rubber, the barrier rib patterning is screen printing, punching, or drilling, and there is a problem that high precision fine processing cannot be performed. It was
In addition, since the partition walls themselves are soft, the partition walls themselves are deformed during bending, and as a result, convection of the dispersion medium occurs, which hinders the movement of the particles between the electrodes or moves the particles regardless of the electrophoresis of the particles. There is a problem that causes deterioration of the display image.

Therefore, the present invention provides an electrophoretic display device which maintains a sealed state between the partition wall and the substrate without damaging the partition wall even when the electrophoretic display device is bent and displays a stable image. It is intended to be provided.

[0011]

The present invention has been made in consideration of the above circumstances. As a first invention, a pair of substrates, electrodes formed on the substrates, and a space between the substrates are filled. And a charged electrophoretic particle dispersed in the dispersion medium,
In an electrophoretic display device having a partition wall formed on one of the substrates and provided in contact with the other substrate to partition the charged electrophoretic particles and the dispersion medium into small sections, the other partition wall is not formed. The gist of the electrophoretic display device is characterized in that the substrate has a flexible surface layer on the side in contact with the partition wall.

The substrate on which the partition wall is not formed is made of the material of the flexible surface layer. The rubber hardness of the flexible surface layer is 10 or more and 90 or more.
It is characterized by the following range. Further, the rubber hardness of the flexible surface layer is in the range of 20 or more and 85 or less.

Further, the flexible surface layer is swollen by the dispersion medium in which the charged electrophoretic particles are dispersed. Further, the flexible surface layer is made of a silicone resin. The dispersion medium in which the charged electrophoretic particles are dispersed is an aliphatic hydrocarbon solvent.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The electrophoretic display device of the present invention comprises a pair of substrates, electrodes formed on the substrates, charged electrophoretic particles sandwiched between the substrates, and a dispersion medium in which the electrophoretic particles are dispersed. In an electrophoretic display device in which a partition for dividing the charged electrophoretic particles and the dispersion medium into small sections is formed on one side, the other substrate on which the partition is not formed has a flexible surface on the side in contact with the partition. It is characterized by having layers.

Next, an embodiment of the present invention will be described with reference to FIGS. Note that these drawings are examples of cross-sectional views showing the configuration of the electrophoretic display device according to the present invention.

The present invention can be applied to an electrophoretic display device (see FIG. 1) in which the so-called charged electrophoretic particles 1 horizontally move and an electrophoretic display device (see FIG. 2) vertically move. Here, the horizontal movement type refers to the first electrode 4a as shown in FIG.
And the second electrode 4b are arranged along one of the substrates 3a or 3b, and the charged electrophoretic particles 1 are attached to the substrate 3a,
3b means configured to move along.
On the other hand, the vertical movement type is, as shown in FIG. 2, a first electrode 4a and a second electrode 4b that sandwich the dispersion medium 2 therebetween.
Are arranged on different substrate sides, and the charged electrophoretic particles 1 are attached to the substrate 3a,
3b means that it is configured to move in the vertical direction (normal direction). The charged electrophoretic particles illustrated in FIGS. 1 and 2 are assumed to be positively charged.

The horizontal movement type electrophoretic display device shown in FIG. 1 will be described below as an example. As shown in FIG. 1, the electrophoretic display device according to the present invention includes a plurality of charged electrophoretic particles 1 and a dispersion medium 2 in which these charged electrophoretic particles 1 are dispersed.
Various images are displayed on the basis of moving the charged electrophoretic particles 1 by applying a voltage.

In this case, it is preferable that the pair of substrates 3a and 3b are arranged with a predetermined gap therebetween, and the above-described charged electrophoretic particles 1 and the dispersion medium 2 are arranged between these substrates 3a and 3b. Further, the first electrode 4a and the second electrode 4b are arranged near the charged electrophoretic particles 1 and the dispersion medium 2, and these electrodes 4a,
Charged electrophoretic particles 1 by applying a voltage between 4b
To move various images to display various images.

In the present invention, the partition 7 is arranged so as to partition the gap between the substrates 3a and 3b into at least one pixel. The partition 7 is formed on either surface of the substrate (in FIG. 1, the partition 7 is formed on the substrate 3b). The arrangement of the partition walls and the distance between the partition walls are not particularly limited as long as they are uniform.

The other substrate (the substrate 3a in FIG. 1) on which the partition wall is not formed according to the present invention has a flexible surface layer 9 on the side where the upper part of the partition wall 7 contacts. Flexible surface layer 9
When pressed by the partition wall 7, the contact portion is deformed into a concave shape to seal the gap between the substrate 3 a and the partition wall 7. As a result, even when the substrate itself of the electrophoretic display device is bent, the partition wall 7 is not damaged, the gap between the partition wall 7 and the substrate 3a remains sealed, and the partition wall itself is deformed. Therefore, the charged electrophoretic particles 1 can stably move between the electrodes, and an image can be stably displayed.

The soft surface layer 9 of the present invention has a rubber hardness of 1
It is preferably 0 or more and 90 or less, and more preferably 20 or more and 85 or less. If the rubber hardness is less than 10, the surface tends to be too soft and tackiness occurs, and particles tend to stick to each other. On the other hand, if the rubber hardness exceeds 90, the surface becomes too hard and the gap between the partition wall and the substrate becomes large. Tend not to be sealed.

The rubber hardness of the flexible surface layer according to the present invention complies with the durometer hardness test described in JIS K6253 and has a coating thickness of 8 mm or more and an A type durometer rubber hardness meter (manufactured by Kobunshi Keiki Co., Ltd.). , Model ASKE
(R-JA type).

The flexible surface layer 9 of the present invention may be swollen by the dispersion medium 2 in which the charged electrophoretic particles 1 used in the present invention are dispersed. Further, within the scope of the present invention, the substrate on which the partition wall is not formed (the substrate 3a in FIG. 1) may be made of the material of the flexible surface layer. In this case, the substrate can also serve as the flexible surface layer.

As the material of the flexible surface layer 9 of the present invention,
It is not particularly limited as long as it satisfies the scope of the present invention, for example, polybutadiene, polybutadiene styrene copolymer, ethylene ethyl acrylate copolymer, ethylene butyl acrylate copolymer, polyurethane, silicone resin, natural rubber, heat Examples thereof include plastic elastomer resins. Among them, a silicone resin is preferable, and a coating silicone resin, a potting silicone resin, and an adhesive silicone resin can be used because they are easily available. For example, Pelgan Z, Silpot 184 (all manufactured by Dow Corning), SE1750, SE4486, SE44
10, JCR6182, CY5205, JCR612
2, PRX305 (all manufactured by Toray Dow Corning), KE1091, KE1602, KE103, KE
106 and KE1800T (both manufactured by Shin-Etsu Chemical Co., Ltd.) are specifically mentioned. These may be used alone or in combination of two or more.

As the method for forming the flexible surface layer 9 of the present invention on the substrate (the substrate 3a in FIG. 1) on which the partition wall is not formed, the above materials are used, and the spin coating method, the gravure coating method, the It can be formed by a known method such as a spray coating method or a bar coating method, but is not particularly limited. Further, a film formed by a known method such as a casting method from a solution or a melt extrusion method using the above-mentioned material for the flexible surface layer 9 is a substrate on which the partition wall of the present invention is not formed (the substrate in FIG. 1). It can also be used as 3a).

The thickness of the flexible surface layer 9 of the present invention depends on the partition wall 7.
The portion pressed by is deformed into a concave shape so that the gap between the substrate 3a and the partition wall 7 can be sealed.
It is preferably not less than μm and not more than 100 μm. When the substrate 3a on which the surface layer 9 is formed is arranged on the observer side, the surface layer 9 is preferably transparent.

The electrophoretic display device of the present invention uses charged electrophoretic particles 1 and a dispersion medium 2 in which the electrophoretic particles are dispersed.

The average particle size of the electrophoretic particles 1 used in the present invention is preferably in the range of 0.05 μm to 20 μm. The particle material is not particularly limited to any of an inorganic material, a polymer material, or a composite material thereof, but specifically, titanium dioxide, silica, alumina, carbon black, an inorganic material such as graphite, polyethylene, polyester, Polymethacrylate, polyacrylate, polystyrene, polyurea, phenol novolac type epoxy resin, cresol novolac type epoxy resin, cycloaliphatic epoxy resin, glycidyl ester epoxy resin, polymethacrylic acid ester, ethylene-acrylic acid copolymer resin, etc. Examples include molecular materials.

Further, as the charged electrophoretic particles used in the present invention, commercially available spherical particles can be used within the scope of the present invention. For example, Micropearl (Sekisui Chemical Co., Ltd.)
, Manufactured by Natco Co., Ltd., manufactured by Natco Co., Epocolor particles manufactured by Nippon Shokubai Chemical Co., Ltd., Chemisnow manufactured by Soken Chemical Co., Ltd., Tospearl manufactured by GE Toshiba Silicones Co., Ltd. However, it is not particularly limited.

The electrified electrophoretic particles 1 of the present invention can be colored according to the display method of the electrophoretic display device used, but the coloring agents are not particularly limited within the scope of the present invention. Specific coloring agents include titanium oxide,
Carbon Black, Nigrosine, Iron Black, Aniline Blue, Calcoil Blue, Chrome Yellow, Ultramarine Blue, DuPont Oil Red, Quinoline Yellow,
Methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal, C.I. I. Pigment Red, C.I. I. Pigment Yellow, C.I. I. Pigment Blue,
C. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Mordant Red 30, C.I. I. Direct Blue 1, C.I. I. Direct Blue 2, C.I.
I. Acid Blue 9, C.I. I. Acid Blue 15,
C. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Mordant Blue 7, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I.
I. Basic Green 6, Yellow Lead, Cadmium Yellow, Mineral Fast Yellow, Navel Yellow, Naphthol Yellow S, Hansa Yellow G, Permanent Yellow NCG, Tartrazine Lake, Molybdenum Orange, Permanent Orange GTR, Benzidine Orange G, Cadmium Red, Permanent Red 4R. , Watching Red Calcium Salt, Brilliant Carmine 3B, Fast Vio Red B, Methyl Vio Red Lake, Navy Blue, Cobalt Blue, Alkali Blue Lake,
Victoria Blue Rake, Quinacridone, Rhodamine B, Fast Sky Blue, Pigment Green B,
Pigments such as Malachite Green Lake, Final Yellow Green G, or Valifast Red, V
alifast Yellow, Oplas Red,
Oil Scarlet [Made by Orient Chemical Co.], Oi
l Blue V, Oil Green, Bright
Green, Sudan IV, Sudan III
[Made by Daiwa Kako Co., Ltd.], Sumiplast Blue, S
umiplast Red HFG, Sumiplas
t Red HF4G, Sumiplast Yell
ow, WhiteflourB (manufactured by Sumitomo Chemical Co., Ltd.),
Macrolex Red GS [manufactured by Bayer Japan]; Microlis Blue, Microli
Oily dyes such as s Green [manufactured by Nippon Ciba Geigy], Orient Oil Black [manufactured by Orient Kagaku], Sumikaron Brilliant
Blue, Sumikaron Violet [Sumitomo Chemical Co., Ltd.], Kayacryl Black, Kay
alon Polyester Blue, Kayar
dyes such as on Polyester Red (manufactured by Nippon Kayaku Co., Ltd.). Further, among these colorants, pigments that can be used alone as the electrophoretic particles can be used within the scope of the present invention.

As the dispersion medium 2 of the present invention, a highly insulating organic solvent having a low conductivity is used. Specifically, benzene,
Aromatic hydrocarbon solvents such as toluene, xylene, naphthene hydrocarbons, hexane, cyclohexane, kerosene, paraffin hydrocarbon solvents, aliphatic hydrocarbon solvents such as isoparaffin hydrocarbons, chloroform, trichloroethylene, dichloromethane, trichlorotri Fluoroethylene, halogenated hydrocarbon solvents such as ethyl bromide, or silicon oil, high-purity petroleum, and the like can be mentioned. Among them, aliphatic hydrocarbon solvents are preferably used,
Specifically, Isopar G, H, M, L (all manufactured by Exxon Chemical Co., Ltd.), Shellsol (Showa Shell Japan), IP Solvent 1016, 1620, 2028,
2835 (Idemitsu Petrochemical). These can be used alone or in combination of two or more.

On the other hand, the dispersion medium 2 used in the present invention can be colored in a color different from that of the particles according to the display method of the electrophoretic display device used. As the colorant, the dispersion medium 2
Is not particularly limited as long as it is an oil-soluble dye that can be dissolved in, but specifically, Oil Yellow 3G, Fast Orange G, Oil Red 5B, Oil Violet #Macrolex Blue RR, Sumiplast Green G, Oil Brown GR, Sudan Black X60, Valif
ast Red, Valifast Yellow, O
plus Red, Oil Scarlet [manufactured by Orient Chemical Co.], Oil Blue V, Oil Gre
en, Bright Green, Sudan IV, S
udanIII [manufactured by Daiwa Kako Co., Ltd.], Sumiplast
Blue, Sumiplast Red HFG, S
umiplast Red HF4G, Sumipla
st Yellow, Whiteflow B [Sumitomo Chemical Co., Ltd.], Macrolex Red GS [Bayer Japan Co., Ltd.], Micropolis Blue,
Microlis Green (manufactured by Nippon Ciba Geigy), Orient Oil Black (manufactured by Orient Chemical Co., Ltd.), Sumikaron Brilliant
Blue, Sumikaron Violet [Sumitomo Chemical Co., Ltd.], Kayacryl Black, Ka
yalon Polyester Blue, Kaya
ron Polyester Red (Nippon Kayaku Co., Ltd.)
Etc.

The dispersion medium 2 may optionally contain a charge control agent, and is soluble in the dispersion medium 2 such as an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a metal soap,
Nonionic surfactants, fluorine-based surfactants, block polymers, graft polymers and the like may be used alone or in combination of two or more.

The substrates 3a and 3b have polyethylene terephthalate (PET) and polyether sulfone (PE).
Polymer films such as S), polyimide (PI), polyethylene naphthalate (PEN), and polycarbonate (PC), or inorganic materials such as glass and quartz can be used.

For the electrodes 4a and 4b, any conductive material that can be patterned can be used, and examples thereof include indium tin oxide (ITO), aluminum and titanium.

In the horizontal movement type electrophoretic display device shown in FIG. 1, one electrode 4b is formed on the entire pixel, and the other electrode 4a is formed on a part of the pixel at a height different from that of the electrode 4b. Although it is formed so as to overlap with the electrode 4b, the present invention is not limited to this, and both electrodes 4a and 4b may be formed at the same height (in this case, the electrode 4b cannot be formed in the entire pixel). , The electrodes 4a and 4b do not overlap each other), or the electrodes may be formed by being divided for each pixel.

Further, the insulating layer 6 may be formed so as to cover the electrodes 4a, 4b and the like. When the insulating layer is formed,
It is possible to prevent charge injection from the electrodes 4a and 4b into the electrophoretic particles 1. The material used for the insulating layer 6 is preferably a thin film that does not easily form pinholes. In particular,
Highly transparent polyimide resin, polyester resin, polyacrylate resin, polymethacrylate resin,
Examples thereof include polycarbonate resin, polyarylate resin, novolac resin, epoxy resin and the like.

The partition wall 7 is made of a resin material having a rubber hardness higher than that of the flexible surface layer 9, and the upper surface of the partition wall is in contact with the flexible surface layer. It suffices that the gap is sealed by deforming the contact portion of the concave shape. The rubber hardness of the partition wall is
The range of 90 or more and 100 or less is preferable, and specific partition wall materials include polyimide resin, polyester resin, polyacrylate resin, polymethacrylate resin, polycarbonate resin, polyarylate resin, novolac resin,
An epoxy resin etc. can be mentioned.

As the method of forming the partition wall 7, a method of applying a photosensitive resin layer and then performing exposure and wet development,
Examples thereof include a method of forming by a printing method, a method of adhering to a substrate after forming a partition wall, a method of forming by a mold on the surface of a light-transmissive substrate, and the like. The width of the partition wall is preferably 50 μm or less, and when the partition wall exceeds 50 μm, it is not preferable because it becomes conspicuous as a display defect (a portion where the movement of particles is not recognized). The height of the partition wall is 10 μm.
It is preferably 100 μm or less.

In the case of the horizontal movement type, the above-mentioned first electrode 4a
Also, of the second electrodes 4b, a region in which one of the electrodes is arranged can be colored with the same color as the charged electrophoretic particles 1, and a region in which the other electrode is arranged can be colored in a different color. In this case, the electrode itself may be colored, and the colored layer may be
The insulating layer may be provided separately from the electrode, the insulating layer may be arranged so as to overlap with the electrode, and the insulating layer may be colored, or any of them may be used.

In the case of the vertical movement type, the dispersion medium 2 for dispersing the charged particles can be colored in a color different from that of the particles 1. Although two-color display is possible with these, by displaying different colors in a plurality of adjacent pixels, it is possible to perform color display as the entire display device.

Next, the effect of this embodiment will be described. According to this embodiment, since the partition wall is pressed against the flexible surface layer of the substrate on which the partition wall is not formed, the gap between the partition wall and the substrate is sealed. Even when folded, the partition wall is not damaged, the gap between the partition wall and the substrate remains sealed, and the partition wall itself is not deformed, so that the particles stably move between the electrodes. be able to. As a result, an image can be stably displayed even when the electrophoretic display device is bent.

[0043]

EXAMPLES The present invention will be described in more detail below with reference to examples of a horizontal movement type electrophoretic display device. The rubber hardness of the flexible surface layer in the present invention is JIS K62.
According to the durometer-hardness test described in No. 53, the film thickness was 8 mm or more, and the measurement was performed with an A-type durometer-rubber hardness meter (Model ASKER-JA type, manufactured by Kobunshi Keiki Co., Ltd.).

Example 1 In this example, the electrophoretic display device shown in FIG. 3 (e) was produced. Note that FIG. 3 is a cross-sectional process diagram showing a method for manufacturing an electrophoretic display device according to the present invention.

First, the polyimide (P
I) Aluminum was evaporated on the surface of the film to a thickness of 100 nm to form the second electrode 4b (FIG. 3 (a)). The polyimide film 3b has a size of 50 mm × 50 mm
A film having a thickness of 00 μm was used. Next, on the surface of the second electrode 4b, a white-colored polyimide resin layer was formed by mixing fine particles of titanium oxide to form an insulating layer 6.

A first electrode 4a is formed on the surface of the insulating layer 6,
As shown in FIG. 3B, it was formed in a partial region of one pixel so as to overlap with the second electrode 4b. Then, the insulating layer 6 made of transparent polyimide was formed so as to cover the first electrode 4a. The first electrode 4a was formed by forming a dark black titanium carbide film and patterning it in a line shape by photolithography and dry etching. The first electrode 4a has a thickness of 50 nm and a line width of 35 nm.
The distance between the first electrodes 4a was 120 μm.

Then, a partition wall 7 was formed on the surface of the insulating layer 6 so as to partition the pixels. The partition wall 7 was formed with a height of 30 μm, a width of 12 μm, and an interval of 120 μm by repeating a process of applying a photosensitive polyimide varnish, a process of exposing and a wet developing process three times.
At this time, the end support members 5 at both ends of the substrate are simultaneously formed,
The height was 25 μm and the width was 20 μm.

Next, a heat-fusible adhesive layer 8 is formed on the upper surfaces (bonding surfaces with the substrate 3a) of the end supporting members 5 at both ends of the substrate, and the charged electrophoretic particles 1 are colored with NATCO beads. (Natco Co., Ltd., average particle size 6 μm) 2 parts by weight, and 100 parts by weight of a dispersion medium 2 made of Isopar G (manufactured by Exxon) which is an aliphatic hydrocarbon solvent of isoparaifine hydrocarbon. Then, 0.1 part by weight of zirconium octenoate as a charge control agent was mixed to prepare a dispersion liquid, and the dispersion liquid was filled in the partition walls 7 (see FIG. 3C).

On the surface of the substrate 3a made of a PET film having a thickness of 200 μm, a silicone resin, Pelgan Z (made by Dow Corning) was formed as a flexible surface layer 9 of the present invention with a thickness of 50 μm. . The rubber hardness of this flexible surface layer was 83 (see FIG. 3D).

The substrate 3a on which the flexible surface layer 9 of the present invention is formed and the adhesive layer 8 are aligned and then heated to heat the substrate 3
The a and the end supporting member 5 were adhered to each other to obtain the electrophoretic display device of the invention (see FIG. 3E). In the obtained electrophoretic display device, the vertical distance between the pixels filled with the dispersion liquid was 27 μm. The upper part of the first electrode 4a is visually recognized as black, and the white part of the insulating layer 6 is visually recognized as the upper part of the region where the first electrode 4a is not arranged.

The applied voltage is ±
The display was performed at 50 V and a voltage application time of 10 msec.

Since the charged electrophoretic particles 1 used in this embodiment are positively charged, they quickly move to the negative electrode when a voltage is applied. For example, the second electrode 4b
When the first electrode 4a has a positive polarity and the first electrode 4a has a negative polarity, the black charged electrophoretic particles 1 move to cover the first electrode 4a (and the white insulating layer 6), and when viewed from the observer side of the substrate 3a, black The particle 1 and the white area (area other than the first electrode 4a) are recognized, and the pixel displays white (see FIG. 1A).

On the contrary, when the second electrode 4b has a negative polarity and the first electrode 4a has a positive polarity, the black charged electrophoretic particles 1
Moves to a white area (area other than the first electrode 4a), so that the black first electrode 4a is seen from the observation side of the substrate 3a.
And the white insulating layer 6 covered with the black particles 1 is visually recognized,
As a pixel, black display is performed (see FIG. 1B). The response speed was 30 msec or less.

Next, while switching the polarity of the applied voltage every 0.5 seconds, the display device was installed so that the display surface was in the vertical direction, and the display device was driven for 3 hours, but no display defect occurred. Then, the substrate itself of the display device was bent, but no display defect occurred.

From the above, according to the present invention, even when the substrate itself of the electrophoretic display device is bent, the partition wall is not damaged, and the gap between the partition wall and the substrate is maintained in a sealed state. Since the partition itself does not deform,
It can be seen that the particles move stably between the electrodes.

Example 2 In this example, 3 parts by weight of black particles 1 made of polyester and carbon black were used as charged electrophoretic particles.
100 parts by weight of a dispersion medium 2 made of Isopar G, which is an isoparaffin-based hydrocarbon (manufactured by Exxon), and 0.5 part by weight of an alkenyl succinic acid polyimide (OLOA1200, manufactured by Chevron Chemical Co.) as a charge control agent. The dispersion was prepared by mixing and used. An electrophoretic display device was produced in the same manner as in Example 1 except for the above structure and manufacturing method. Using the display device manufactured in Example 1, display was performed with an applied voltage of ± 50 V and an applied voltage of 10 msec.

Since the charged electrophoretic particles 1 used in this example are negatively charged, they quickly move to the positive electrode when a voltage is applied. For example, the second electrode 4b
When the positive electrode has a positive polarity and the first electrode 4a has a negative polarity, the black charged electrophoretic particles 1 have a white region (region other than the first electrode 4a).
Therefore, when viewed from the observation side of the substrate 3a, the black first electrode 4a and the white insulating layer 6 covered with the black particles 1 are formed.
Is visually recognized, and a black display is performed as a pixel.

On the contrary, when the second electrode 4b has a negative polarity and the first electrode 4a has a positive polarity, the black charged electrophoretic particles 1
Move to cover the first electrode 4a, and when viewed from the observation side of the substrate 3a, the black particles 1 and the white area (area other than the first electrode 4a) are recognized, and the pixel displays white. Becomes The response speed was 30 msec or less.

Next, while switching the polarity of the applied voltage every 0.5 seconds, the display device was installed so that the display surface was in the vertical direction, and the display device was driven for 3 hours, but no display defect occurred. Then, the substrate itself of the display device was bent, but no display defect occurred.

Example 3 In this example, except that a sill pot 184 (made by Dow Corning, rubber hardness 45) of silicon resin was formed on the surface of a substrate 3a made of a PET film having a thickness of 200 μm with a thickness of 50 μm. An electrophoretic display device was produced under the same conditions as in Example 1. The applied voltage is ± 50
The display was performed at V and a voltage application time of 10 msec. Since the charged electrophoretic particles 1 in this example are positively charged, they moved so as to cover the negative electrode. The response speed was 30 msec or less.

Next, while switching the polarity of the applied voltage every 0.5 seconds, the display device was installed so that the display surface was in the vertical direction, and the display device was driven for 3 hours, but no display defect occurred. Then, the substrate itself of the display device was bent, but no display defect occurred.

Example 4 In this example, the surface of the substrate 3a made of a PET film having a thickness of 200 μm was coated with KE10 which was a silicone resin.
6 (manufactured by Shin-Etsu Chemical Co., Ltd., rubber hardness 59) having a thickness of 50 μm was used to prepare an electrophoretic display device under the same conditions as in Example 1. The applied voltage was ± 50 V and the voltage application time was 10 msec. Since the charged electrophoretic particles 1 in this example are positively charged, they moved so as to cover the negative electrode. Response speed is 30 msec
It was below.

Next, while switching the polarity of the applied voltage every 0.5 seconds, the display device was installed so that the display surface was in the vertical direction, and the display device was driven for 3 hours, but no display defect occurred. Then, the substrate itself of the display device was bent, but no display defect occurred.

Example 5 In this example, instead of the substrate 3a made of a PET film having a thickness of 200 μm, a film (thickness 200 μm) of Pelgan Z (made by Dow Corning Co., Ltd., rubber hardness 83) which is a silicon resin is used. An electrophoretic display device was produced under the same conditions as in Example 1 except that the above was performed. The applied voltage was ± 50 V and the voltage application time was 10 msec. Since the charged electrophoretic particles 1 in this example are positively charged, they moved so as to cover the negative electrode. The response speed was 30 msec or less.

Next, while switching the polarity of the applied voltage every 0.5 seconds, the display device was installed so that the display surface was in the vertical direction, and the display device was driven for 3 hours, but no display defect occurred. Then, the substrate itself of the display device was bent, but no display defect occurred.

Comparative Example 1 Substrate 3a made only of a PET film having a thickness of 200 μm
Except that the upper part of the partition wall 7 and the substrate 3a are adhered using
An electrophoretic display device was produced under the same conditions as in Example 1. The applied voltage was ± 50 V and the voltage application time was 10 msec. Since the charged electrophoretic particles 1 in this example are positively charged, they moved so as to cover the negative electrode. The response speed was 30 msec or less.

Next, while switching the polarity of the applied voltage every 0.5 seconds, the display device was installed so that the display surface was in the vertical direction, and the display device was driven for 3 hours, but no display defect occurred. Then, the substrate itself of the display device was bent, but the partition wall was damaged and the adhesive portion between the partition wall and the substrate was peeled off, resulting in display failure.

Comparative Example 2 The same conditions as in Example 1 except that JCR6120F (manufactured by Toray Dow Corning Co., Ltd., rubber hardness 7) having a thickness of 50 μm was formed on the surface of the substrate 3a made of a PET film having a thickness of 200 μm. Then, an electrophoretic display device was produced. The applied voltage is ± 50 V and the voltage application time is 10
The display was made in msec. Since the charged electrophoretic particles 1 in the present example are positively charged, they move so as to cover the negative electrode, but the particles adhere to the silicon resin layer formed on the surface of the substrate 3a, resulting in a display error. The contrast is greatly reduced.

Comparative Example 3 An electrophoretic display device was produced under the same conditions as in Example 1 except that the substrate 3a made of only a PET film having a thickness of 200 μm (rubber hardness 99) was used. The applied voltage is ±
The display was performed at 50 V and a voltage application time of 10 msec. Since the charged electrophoretic particles 1 are positively charged, they move so as to cover the negative electrode. Response speed is 30 mse
It was less than or equal to c.

Next, while switching the polarity of the applied voltage every 0.5 seconds, the display device was installed and driven so that the display surface was in the vertical direction. Within 30 minutes, the particles exceeded the partition wall. It moved to the adjacent section and the density unevenness of the display occurred.

[0071]

As described above, according to the present invention,
Since the partition wall is pressed against the flexible surface layer formed on the substrate on which the partition wall is not formed, the gap between the partition wall and the substrate is sealed. Not only is it suppressed from moving beyond, but even when the substrate of the electrophoretic display device is bent, the partition wall is not damaged and the gap between the partition wall and the substrate is kept sealed, and Since the partition walls themselves are not deformed, the particles can stably move between the electrodes, and a stable image can be displayed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of the structure of an electrophoretic display device according to the present invention.

FIG. 2 is a cross-sectional view showing an example of a structure of an electrophoretic display device according to the present invention.

FIG. 3 is a process drawing showing the method for manufacturing the electrophoretic display device according to the present invention.

FIG. 4 is a cross-sectional view showing an example of the structure of a conventional electrophoretic display device.

FIG. 5 is a cross-sectional view showing an example of the structure of a conventional electrophoretic display device.

[Explanation of symbols]

1 Electrophoretic particles 2 dispersion medium 3a, 3b substrate 4a first electrode 4b Second electrode 5 End support member 6 insulating layers 7 partition 8 Adhesive layer 9 Flexible surface layer

Claims (7)

[Claims] 1. A pair of substrates, electrodes formed on the substrates, a dispersion medium filled between the substrates, charged electrophoretic particles dispersed in the dispersion medium, and the other formed on one of the substrates. In the electrophoretic display device having the partition wall that is in contact with the substrate and that divides the charged electrophoretic particles and the dispersion medium into small sections, the other substrate on which the partition wall is not formed is in contact with the partition wall. An electrophoretic display device having a flexible surface layer on its side. 2. The electrophoretic display device according to claim 1, wherein the substrate having no partition wall is made of the material of the flexible surface layer. 3. The electrophoretic display device according to claim 1, wherein the flexible surface layer has a rubber hardness in the range of 10 or more and 90 or less. 4. The electrophoretic display device according to claim 1, wherein the rubber hardness of the flexible surface layer is in the range of 20 or more and 85 or less. 5. The electrophoretic display device according to claim 1, wherein the flexible surface layer is swollen by the dispersion medium in which the charged electrophoretic particles are dispersed. 6. The electrophoretic display device according to claim 1, wherein the flexible surface layer is made of a silicone resin. 7. The electrophoretic display device according to claim 1, wherein the dispersion medium in which the charged electrophoretic particles are dispersed is an aliphatic hydrocarbon solvent.