JP2007192880A - Electrophoresis display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin electrophoresis display device having flexibility. <P>SOLUTION: The electrophoresis display device has the arrangement of a light transmissive substrate for forming an electrode, a substrate having the electrode arranged counter to the substrate, an electrophoresis display liquid including at least one or more kinds of electrophoresis particles filling a gap between the opposite substrates, a seal part for sealing the display liquid between the substrates, and a mesh-like sheet body between the counter substrates. The electrophoresis display device has a stress relieving part for relieving stress on at least a displaying part out of the mesh-like sheet body. The electrophoresis display device maintains a proper substrate interval, prevents a short circuit or the like due to contact of the counter substrate, has the effect of suppressing coagulation and maldistribution of charge particles, effectively relieves stress applied externally by the stress relieving part, stress due to a curing contraction of an adhesive used for adhesion and contraction of the substrate, and stress generated during assembly and impairs no display quality or no drive characteristics. <P>COPYRIGHT: (C)2007,JPO&INPIT

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 more particularly to a thin electrophoretic display device having flexibility.

  In recent years, with the development of information equipment, the demand for low power consumption, thinning, and flexibility of display devices has increased, and research and development of display devices that meet these demands have been actively conducted. .

  As one of such display devices, an electrophoretic display device invented by Harold D. Lees et al. (For example, see Patent Document 1) is known. In this electrophoretic display device, two electrode substrates, at least one of which is transparent, are arranged to face each other via a suitable spacer, and between these electrode substrates, electrophoretic particles (pigment particles, etc.) having either positive or negative charge are placed. The display particles are dispersed in a solvent colored in a different color and the dispersion is filled between the substrates to form a display panel. An electric field is applied to the display panel to obtain a display on the transparent electrode surface.

  The electrophoretic display liquid filled between the electrode substrates is low in xylene, tetrachloroethylene, paraffin, silicone oil or the like in which electrophoretic particles such as titanium dioxide and a dye for contrasting the electrophoretic particles are dissolved. It is composed of a dispersion solvent of dielectric constant, a dispersant such as a surfactant, and an additive such as a charge imparting agent. By applying an electric field to the electrophoretic display liquid, the electrophoretic particles in the ink move to the transparent electrode side, and the color of the fine particles appears on the display surface. By applying an electric field in the opposite direction, the electrophoretic particles are It moves to the opposite side, and the color of the dispersion colored with the dye appears on the display surface.

  Such an electrophoretic display device is a display device 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 less power, and displays. It has attracted attention as an inexpensive display device because of its advantages such as having a memory property.

  However, the fine particles used in the electrophoretic display liquid may deteriorate due to the aggregation of the particles when stored for a long time, or the uneven distribution of particles during repeated display. Has the problem that it is easy to occur.

  As a method for preventing display non-uniformity due to uneven distribution of electrophoretic display fine particles on the display surface, particles can be obtained by filling an electrophoretic display liquid in a number of small chambers (cells) that have been finely isolated. Many methods for suppressing aggregation and uneven distribution of each other, a configuration of a small room (cell), a manufacturing method, and the like have been proposed (see, for example, Patent Documents 2 to 8).

  According to the above method and the like, it is possible to suppress aggregation and uneven distribution of particles, but walls and the like that form a large number of small cells (cells) are formed in a state of being fixed, adhered, or the like to the substrate. Therefore, when it is curved as a thin electrophoretic display device, there is a problem that stress acts between the wall and the substrate, and the wall is easily broken or the display is deteriorated.

  In addition, in order to keep the distance between the electrodes constant, or to keep the thickness of the dispersion constant, a display device is proposed that includes a blocking substance made of an insulating porous layer (such as a mesh). (For example, see Patent Documents 9 and 10). According to this method, short-circuiting is prevented, the thickness can be kept uniform, and the lateral flow of the dispersion is prevented. However, externally applied stress, curing shrinkage of the adhesive used for adhesion, etc. In addition, the stress due to the shrinkage of the substrate and the stress generated during the assembly cannot be effectively relaxed yet, display unevenness occurs, and there is a problem in that the durability is not yet sufficient.

On the other hand, a method for encapsulating an electrophoretic display liquid in microcapsules and using it as display particles (for example, see Patent Document 11), or at least two types of electrophoresis in which a color tone and electrophoretic property are different from each other in a colorless dispersion medium An example in which a liquid in which a fine particle is dispersed is encapsulated in a microcapsule has also been proposed (see, for example, Patent Document 12).
However, according to this technique, even if it is curved as a thin electrophoretic display device, the stress is relieved because it has a certain degree of flexibility. It is necessary to go through a process such as coating, and there is a problem that a complicated method has to be taken for manufacturing an electrophoretic display device.
US Pat. No. 3,612,758 (Claims, Examples, etc.) JP-A-49-61075 (Claims, Examples, etc.) JP-A-5-61075 (Claims, Examples, etc.) JP 2001-159765 A (Claims, Examples, etc.) JP 2002-148862 A (claims, examples, etc.) JP 2002-292736 A (Claims, Examples, etc.) JP 2004-20640 A (Claims, Examples, etc.) Japanese Patent No. 3189958 (Claims, Examples, etc.) Japanese Patent Publication No. 50-15355 (Claims, Examples, etc.) JP-A-2005-345573 (Claims, Examples, etc.) Japanese Patent No. 2551783 (Claims, Examples, etc.) WO98 / 03896 (Claims, Examples, etc.)

  The present invention has been made in view of the above-mentioned problems of the prior art, and is intended to solve this problem. It suppresses aggregation and uneven distribution of particles in an electrophoretic display device, and is used for externally applied stress and adhesion. By effectively mitigating stress due to curing shrinkage of the substrate, substrate shrinkage, and stress generated during assembly, the display quality and drive characteristics are not impaired, and the electrophoretic display device having flexibility is also deformed. It is an object of the present invention to provide an electrophoretic display device that can maintain a stable substrate gap (gap) and can be manufactured at low cost.

  As a result of intensive investigations to solve the above-described conventional problems, the present inventor formed between a substrate placed oppositely and a liquid for electrophoretic display containing at least one kind of electrophoretic particles and the substrate. In the electrophoretic display device comprising the mesh sheet body, by finding a specific structure at least in the display portion of the mesh sheet body, it is found that the target electrophoretic display device can be obtained, The present invention has been completed.

That is, the electrophoretic display device of the present invention exists in the following (1) to (3).
(1) For electrophoretic display comprising a light-transmissive substrate on which an electrode is formed, a substrate having an electrode disposed opposite to the substrate, and at least one kind of electrophoretic particles filled between the opposed substrates An electrophoretic display device in which a liquid, a seal portion that seals the display liquid between substrates, and a mesh-like sheet body disposed between the counter substrates, the display being at least displayed among the mesh-like sheet bodies An electrophoretic display device characterized in that the portion has a stress relaxation portion that relaxes against stress.
(2) The electrophoretic display device according to the above (1), wherein the stress relaxation portion is constituted by a cut portion formed in at least a part of the mesh-like sheet body.
(3) The above-described (1) or (2), wherein the mesh-shaped sheet body is composed of any one of a woven body composed of fibers, a non-woven body formed without interweaving fibers, and a film. Electrophoretic display device.

  According to the present invention, it is possible to suppress aggregation and uneven distribution of particles in an electrophoretic display device, against externally applied stress, stress due to curing shrinkage of an adhesive used for adhesion and contraction of a substrate, and stress generated during assembly. However, it is possible to effectively relax, without impairing display quality and driving characteristics, and also in a flexible electrophoretic display device, it is possible to maintain a stable substrate interval (gap) corresponding to deformation. In addition, an electrophoretic display device that can be manufactured at low cost is provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 to 2 are drawings showing a first embodiment of the electrophoretic display device of the present invention. FIG. 1A is a schematic sectional view of the electrophoretic display device, FIG. (a) is a partially exploded perspective view, (b) is a partial plan view of a mesh-like sheet body, and (c) is a cross-sectional view of the mesh-like sheet body.

  The electrophoretic display device A according to the present embodiment is composed of an electrophoretic display liquid containing at least an insulating liquid, one or more kinds of electrophoretic particles, and a textile body between substrates 10 and 15 arranged to face each other. The mesh-like sheet body 20 is provided, and at least a portion to be displayed of the mesh-like sheet body 20 has a stress relaxation portion 25 that relaxes against stress.

In the present embodiment, as the substrates 10 and 15 having the electrodes 10a and 15a disposed to face each other, for example, a transparent conductive material such as ITO or ZnO is applied to a transparent resin film or transparent glass, an ion plating method, A light-transmitting material formed by a vapor deposition method such as a sputtering method, or a material in which a conductive material film (layer) such as a metal is formed on the surface of a non-conductive material such as a resin film, a resin plate, glass, ceramics, A metal plate can be used.
These substrates 10 and 15 can be formed by patterning by a conventionally used method such as photoetching, or a TFT (Thin Film Transistor) substrate used in a liquid crystal or the like. Although it is possible to use, it is not limited to these.
Further, when used as a display device, at least one of the counter substrates is a light-transmitting substrate, but it is naturally possible to use not only the display surface side but also the back surface side as a light-transmitting substrate. is there.

As the insulating liquid used in the present invention, various types conventionally used for electrophoretic display can be used.
Specifically, aliphatic hydrocarbons such as aromatic hydrocarbons, hexane, cyclohexane, kerosene, isopar, paraffin hydrocarbons, halogenated hydrocarbons, phosphate esters, phthalate esters, carboxylic acids Examples thereof include, but are not limited to, esters, chlorinated paraffin, N, N-dibutyl-2-butoxy-5-tertioctylaniline, and the like.

  As the charged fine particles to be electrophoretic particles used in the present invention, colored or colorless (white) inorganic pigment particles, organic pigment particles, polymer fine particles, and the like can be used. The pigment particles defined in the present invention are those that have low solubility in an insulating liquid in combination with the insulating liquid used as a dispersion medium, and can exist in a dispersed particle state in the insulating liquid. .

  Examples of inorganic pigment particles that can be used include titanium dioxide, zinc sulfide, calcium carbonate, silica, calcium silicate, antimony oxide, kaolin, mica, barium sulfate, gloss white, alumina white, talc, cadmium yellow, and yellow oxidation. Iron, titanium yellow, cadmium orange, molybdate orange, bengara, red lead, silver vermilion, cadmium red, brown iron oxide, zinc iron, chrome brown, chrome green, chromium oxide, viridian, cobalt green, cobalt chrome green, bitumen, cobalt Examples include blue, ultramarine blue, cerulean blue, cobalt violet, carbon black, iron black, black low-order titanium oxide, aluminum powder, copper powder, lead powder, tin powder, and zinc powder.

  Examples of organic pigment particles that can be used include fast yellow, disazo yellow, condensed azo yellow, isoindoline yellow, quinophthaloin yellow, benzimidazolone yellow, monoazo yellow lake, dinitroaniline orange, perinone orange, and naphthol red. , Toluidine Red, Permanent Carmine, Brilliant Fast Scarlet, Rhodamine 6G Lake, Permanent Red, Lake Red, Priliant Carmine, Naphthol Red, Quinacridone Magenta, Condensed Azo Red, Naphthol Carmine, Berylens Car Red, Condensed Azo Scar Red, Perylene Red, Quinacridone red, diketopyrrolopyrrole red, benzimidazolone brown, phthalocyanine green, Victoria Bull Lake, Phthalocyanine Blue, Fast Sky Blue, Rhodamine B lake, methyl violet lake, dioxazine violet and the like.

  As the polymer fine particles that can be used, polymer fine particles comprising an organic polymer produced by a conventionally known method can be used. For example, a method using emulsion polymerization, a seed emulsion polymerization method, a soap-free method. Polymerization method, dispersion polymerization method, suspension polymerization method, seed polymerization method, method using seed polymerization + polymerization shrinkage, method using suspension polymerization of W / O / W emulsion, surface drying of spray-dried droplets Examples thereof include a seed agglomeration method in which a polymer emulsion is agglomerated by adding electrolyte solid particles, but is not limited to those produced by these methods.

  In addition, as the material of the polymer fine particles, a material selected from conventionally known polymer materials can be used in a combination that does not dissolve in a transparent dispersion medium used for electrophoretic display. Examples of these are styrene, styrene-acrylic, styrene-isoprene, divinylbenzene, methyl methacrylate, methacrylate, ethyl methacrylate, ethyl acrylate, n-butyl acrylate, acrylic acid, acrylonitrile , Acrylic rubber-methacrylate, ethylene, ethylene-acrylic acid, nylon, silicone, urethane, melamine, benzoguanamine, phenol, fluorine (tetrachloroethylene), vinylidene chloride, quaternary pyridinium salt, Polymer materials such as synthetic rubber, cellulose, cellulose acetate, chitosan, calcium alginate and the like, and polymer materials whose solvent resistance function has been improved by crosslinking these polymer materials can be mentioned. Material comprising a crosslinked acrylic resin component is preferred from the viewpoint of solvent resistance, but not limited to polymeric materials.

Furthermore, these polymer fine particles may be colored with a dye or a pigment by a known method. For example, a method of producing a monomer using the above method after coloring the monomer before the synthesis of the polymer fine particles. And a method of coloring during the production of the polymer fine particles, a method of coloring after producing the polymer fine particles, and the like.
Furthermore, as another method, it can also be obtained by physically dispersing a dye or pigment in the polymer material obtained by synthesis in advance and then pulverizing to a desired particle size, The colored polymer fine particles are not limited to those obtained by these methods.

At least one kind of these charged particles is used. However, when one kind of charged particles is used, the color of the charged particles is different from the color tone, and the color can be displayed with contrast as the particles move. It will be used in combination with a colored insulating liquid.
For example, when white particles are used as the charged particles, the color of the insulating liquid is used as a type colored with an oil-soluble dye such as oil blue.

On the other hand, when two types of charged particles are used, particles that are oppositely charged with each other and that have different color tones capable of contrast display are used in combination.
For example, when negatively charged white particles are selected as one particle, positively charged black particles can be selected and combined as the other particle. In this case, the color of the insulating liquid is preferably colorless and transparent, but the insulating liquid can be further colored and used. Further, two or more kinds of particles having different charge amounts and colors of charged particles can be used in appropriate combination.

  In the present invention, in addition to the insulating liquid constituting the electrophoretic display liquid 17 and one or more kinds of charged particles, a charge adjusting agent, a dispersant, a surfactant, a hygroscopic agent, and the like are conventionally used for electrophoretic display. Various types can be used as appropriate.

The mesh-like sheet body 20 provided between the substrates 10 and 15 of the present invention is a mesh-like (mesh-like) sheet body, and at least a portion to be displayed of the sheet body 20 is a stress relaxation portion that relaxes against stress. If it is a structure which has 25, it will not specifically limit.
As shown in FIG. 1 and FIG. 2, the mesh-like sheet body 20 of the present embodiment has a high aperture ratio and is knitted with fibers so as to suppress aggregation and uneven distribution of charged particles. It consists of a plain weave fabric. In addition, the mesh-like sheet body 20 made of a woven body has a high aperture ratio, and, if it is a woven body that can suppress aggregation and uneven distribution of charged particles, in addition to a plain weave, for example, a single tissue. You may comprise a certain weave texture, a satin weave, a satin weave, or a woven fabric structure formed by a combination thereof. Preferably, from the viewpoint of smoothness and shape stability, the mesh-like sheet body 20 made of a woven body is preferably composed of a plain weave.
FIGS. 2B and 2C are a plan view and a side view in the case where the mesh-like sheet body 20 made of a woven body is configured by plain weaving. Moreover, in order to improve the stability of the shape of the mesh-like sheet body 20 made of a woven body, a secondary process such as a pressing process, an adhesion process, or a welding process may be performed during or after the formation process of the woven body.

  Examples of the fibers 21 forming the mesh-like sheet body 20 made of this woven body include polyester resins such as PET, polyarylate resins, polyacetal resins, acrylic resins, polyamide resins, polyurethane resins, and polyolefin resins. Resin, polyvinyl resin, polycarbonate resin, polyether resin, polyphenylene resin and other synthetic fibers, and fibers composed of liquid crystal polymers as raw materials can also be cited. Also derived from animals such as wool and eyelashes Mention may also be made of fibers. Furthermore, it is also possible to use plant-derived fibers taken from trees or grass, inorganic fibers such as glass wool and asbestos, and mineral fibers. Preferably, polyester and polyamide fibers can be mentioned from the viewpoints of strength, cost, compatibility with the electrophoretic display liquid, but are not limited thereto. In addition to the multi-core fiber called multifilament, the fiber may be a single-core fiber called monofilament fiber, and the material of the fiber is a composite material combining the above materials, or a fiber made of a plurality of materials. Alternatively, a composite fiber obtained by twisting together may be used. Further, when forming the mesh-like sheet body 20 made of a woven body, a plurality of types of fibers are combined, the warp and weft of the woven body 20 are made of different materials, those having different diameters, or the above contents May be combined as appropriate.

Furthermore, by using a fiber having a rough surface, when the electrophoretic display liquid is stored in the mesh-like sheet body 20 made of a woven body, the fiber is colored in the approximate color of the ink and becomes inconspicuous at the time of display. Thus, the display quality on the appearance can be improved. As a method for roughening the fiber surface, for example, the fiber surface to be used is solvent treatment, acid treatment, alkali treatment, ozone treatment, plasma treatment, corona discharge treatment, UV treatment, UV ittro treatment, laser treatment, and electron beam. Although it can carry out by the process by a process, a primer process, surfactant processing, and sputtering, it is not limited to these.
On the other hand, the above-mentioned fibers can be colored or colored in advance. For example, by using fibers colored in an approximate color to the electrophoretic display liquid, the display quality on appearance can be improved. It is also possible.

  Further, the diameter (d) of the fibers 21 to be used is desirably thin from the viewpoint of various performances such as display characteristics and responsiveness, preferably 1 to 200 μm, and more preferably 1 to 50 μm. Furthermore, the cross-sectional shape of the fiber 21 is preferably a circular shape, and by using a circular fiber, the contact area with the substrate 10 is increased when the mesh sheet 20 made of a woven fabric is sandwiched between the substrates. As a result, the display area can be increased.

The number of the partition portions (mesh portions) 22 of the mesh-like sheet body 20 made of a woven fabric constituted by a woven fabric structure such as a plain weave is determined by the number of meshes (number of fibers driven per inch), and each partition portion. Each side length of 22 is calculated by the number of meshes and the fiber diameter. Specifically, it is calculated by [25400 / number of meshes−wire diameter (d)] (μm). The aperture ratio on an arbitrary surface is calculated by (number of meshes in the longitudinal direction × fiber diameter of the weft) × (number of meshes in the lateral direction × fiber diameter of the warp) / area of the arbitrary surface.
Therefore, a mesh composed of a woven body composed of plain weave, oblique weave, satin weave, etc. having an arbitrary opening ratio and opening surface by suitably combining the fiber diameter (wire diameter, d) and the number of fibers driven in. The sheet-like sheet 20 can be set as appropriate.
In general, when a secondary process such as a pressing process, an adhesive process, or a welding process is performed, the fiber itself is deformed or the adhesive ratio intervenes to reduce the aperture ratio by about several percent.

The aperture ratio a of the mesh-like sheet body 20 made of a woven material is preferably 50% or more, more preferably 70 to 97%, from the viewpoint of obtaining clear display performance, that is, high contrast display. The opening area of each partition 22 is preferably 1 × 10 to 10 × 10 ⁻⁴ mm ² , more preferably 1 to 10 × 10 ⁻³ mm ² from the viewpoint of suppressing aggregation of the electrophoretic particles. It is desirable to do.
In addition, an aperture ratio refers to the ratio which the area which is completely missing when the mesh-like sheet body 20 which consists of a textile body from the display surface side accounts for a unit area.

When the mesh-like sheet body 20 made of the woven material has a distance between substrates t (μm), a thickness of a layer composed of fibers is D (μm), and an aperture ratio of a layer composed of fibers is a. It is desirable to satisfy the following formula (I).
(T / D) × a ≦ 0.95 (I)
The inter-substrate distance t is an element that governs display response and driving voltage, but is preferably 300 μm or less, and more preferably 3 to 100 μm from the viewpoint of display performance and assembly. Desirably, it is appropriately adjusted according to the characteristics of the display member to be used.
The thickness D of the mesh-like sheet body 20 made of a woven material represents the thickness of the end face on the substrate 10 side and the end face on the substrate 15 side in the cross section when sandwiched between the substrates.

In the above formula (I), when (t / D) × a is larger than 0.95, the layer composed of fibers is too far away from the substrates 10 and 15 and the gap becomes difficult to be stabilized. In the case of a display medium provided with, display blur or the like occurs, and the stability of display performance is impaired.
Therefore, in the present invention, the mesh-like sheet body 20 made of a woven body is also present so that the mesh-like sheet body 20 made of the woven body stably exists over time in the space between the opposing substrates, and a desired display performance is obtained. It is preferable to satisfy the above formula (I). Note that the lower limit of (t / D) × a is desirably 0.40 or more from the viewpoint of maintaining good display characteristics and securing a display area.

In the mesh-like sheet body 20 made of a woven body provided between the substrates 10 and 15 of the present embodiment, at least a portion to be displayed of the sheet body 20 is subjected to externally applied stress and curing of an adhesive used for adhesion. A stress relaxation portion 25 that effectively relieves stress against the stress caused by the shrinkage and the shrinkage of the substrate, the stress generated during assembly, and the like is formed.
This stress relaxation part 25 is comprised by forming a notch part in the part displayed at least among the mesh-like sheet bodies 20 which consist of a textile body, as shown in FIG.1 (b).
The incision portion serving as the stress relieving portion 25 has an arrangement location, the number of arrangements, a shape, a length, a size, and the like according to the size, thickness, desired bending amount, display liquid type, and constituent material type of the electrophoretic display device. It will vary depending on the situation. Specifically, as the arrangement location, the vicinity of the seal portion, the center of the display body, the number of arrangement is 1 to about half the number of meshes (for example, in the case of 100 mesh / inch, 1-50 slits / inch). The shape includes a straight line, a dotted line, a broken line, a wavy line, a meander line, a circular continuous arrangement, etc., and those arranged in an X shape, a U shape, a square shape, a parallel shape, etc. When the number of meshes is parallel to the weaving direction, about 50% to 90% of the display area. When not parallel, when viewed from the side direction, the size (slit width) is about 50% to 90% of the display area. ) Can be appropriately set to be over 0 (excluding 0 (zero), the same applies hereinafter) to about three times the opening (OP) width.
In this embodiment, it is composed of a polyarylate fiber (fiber diameter d: 23 μm), a display portion 50 × 50 mm, a plain weave mesh-like sheet body 20 (D = 45 μm) with an opening ratio of 76%, and the vicinity of the four-side main seal 30 In addition, the stress relaxation portion 25 is formed by providing a cut of 0.1 mm that does not exceed the opening width. The length of the cut (slit) is preferably at least half of the side length of the display surface, and in this embodiment, each side (T) is 40 mm. Further, the distance between the substrates is 50 μm.

In the electrophoretic display medium A of the present embodiment, a mesh-like sheet body 20 made of a woven body is placed in a space where the substrate 10 and the substrate 15 are arranged to face each other, and electrophoretic display is performed on each partition 22 of the woven body 20. It is obtained by containing the liquid 17 and sealing the periphery of the space portion with the seal portion 30. In the present embodiment, the peripheral end 26 of the mesh-like sheet body 20 made of a woven body is embedded in the seal portion 25. Specifically, as shown in FIG. 2A, a thermosetting adhesive, a UV curable adhesive, an anaerobic curable adhesive, a natural curable adhesive, and two liquids that constitute a seal portion on the substrate 15. An adhesive such as a mixed type (chemical reaction curing type) adhesive is applied to the periphery of the display portion, and the adhesive is cured to form a seal portion, and the peripheral edge of the mesh sheet 20 made of a woven body 26 is fixed in the seal portion 25.
In the present embodiment, the space between the substrates 10 and 15 is filled with and accommodated with a display material 17 such as an electrophoretic display liquid. In this space, the substrates 10 and 15 and the fabric body are used. There is a gap with respect to the surface direction in the portion of the mesh-like sheet 20 that is not the intersection of the fibers 21, 21,..., And the partition portions 22, 22. Thus, uniform filling is possible even by a general vacuum filling method or the like.

In the electrophoretic display device A of this embodiment configured as described above, the mesh-like (mesh-like) sheet body 20 made of a woven body prevents proper substrate spacing and short-circuiting due to contact with the counter substrate. Stress, which has an effect of suppressing aggregation and uneven distribution of charged particles, and is applied externally by the stress relaxation unit 25 (when the electrophoretic display medium is slightly deformed by external force), The sheet body 20 expands and contracts by the stress relaxation portion 25 and effectively relieves stress due to the stress caused by the curing shrinkage of the adhesive used for bonding, the shrinkage of the substrate, and the stress generated during assembly. It is possible to maintain a stable substrate gap (gap) in response to deformation without sacrificing display quality and driving characteristics, and also in flexible electrophoretic display devices. Rukoto can, moreover, the ones that can be produced at a low cost.
In particular, a thin electrophoretic display device having flexibility is characterized by being deformable, but such an electrophoretic display device exerts a tremendous effect.

FIG. 3 shows a second embodiment of the electrophoretic display device of the present invention and is a plan view of a mesh-like sheet body 20 made of a woven body.
This embodiment is composed of a mesh-like sheet body 20 made of a woven fabric as in the first embodiment, and is different only in that the form of cutting of the stress relaxation portion 25 is different from the first embodiment. Other structures and the like are the same as those in the first embodiment and function in the same manner. The same applies to other embodiments such as the following third to seventh embodiments.
Although the stress relaxation part 25a of this embodiment is comprised by forming an incision part in the part displayed at least among the mesh-like sheet bodies 20 which consist of a textile body, specifically, FIG. As shown, a polyarylate fiber (fiber diameter d: 23 μm), a display portion 50 × 50 mm, a plain weave mesh-like sheet body 20 (D = 45 μm) with an opening ratio of 76% (D = 45 μm) is provided near the main seal 30 on four sides. The stress relaxation portion 25a is formed by providing a cut having a width not exceeding the opening width and a cut having a width as close as possible to 0 mm. The cuts (slits) are discontinuous, and the length thereof is desirably half or more of the side length of the display surface. In this embodiment, four cuts of 40 mm per side are cut. Further, the distance between the substrates is 50 μm.
In the electrophoresis apparatus of this embodiment, it is easy to process by forming a cut, and the opening (mesh part) does not widen, and exhibits the effect of further suppressing aggregation and uneven distribution of charged particles by the mesh part. It becomes.

FIG. 4 shows a third embodiment of the electrophoretic display device of the present invention, and is a plan view of a mesh sheet 20 made of a woven fabric.
Although the stress relaxation part 25b of this embodiment is comprised by forming a cut | notch part in the part displayed at least among the mesh shaped sheet | seat bodies 20 which consist of a textile body, specifically, in FIG. As shown, a polyarylate fiber (fiber diameter d: 23 μm), a display portion 50 × 50 mm, a plain weave mesh-like sheet body 20 (D = 45 μm) with an opening ratio of 76% (D = 45 μm) The stress relaxation portion 25b is formed by providing a discontinuous circular cut (diameter 0.3 mm) by driving. The incision (slit) is a discontinuous circular incision, and is preferably half or more of the side length of the display surface, and is 40 mm in this embodiment. In addition, it is preferable that the diameter of the notch 25b is 0 to 3 times the mesh pitch from the viewpoint of harmony with stress relaxation and aggregation prevention. Further, the distance between the substrates is 50 μm.
In the electrophoresis apparatus of this embodiment, since it is punched into a circular shape, it is easy to process, the mesh misalignment is difficult to place, and the opening (mesh portion) does not spread, and the charged particles are aggregated or unevenly distributed by the mesh portion. Further, the suppressing effect is exhibited.

FIG. 5 shows a fourth embodiment of the electrophoretic display device of the present invention, and is a plan view of a mesh-like sheet body 20 made of a woven body.
Although the stress relaxation part 25c of this embodiment is comprised by forming a cut | notch part in the part displayed at least among the mesh-like sheet bodies 20 which consist of a textile body, specifically, FIG. As shown, a polyarylate fiber (fiber diameter d: 23 μm), a display portion 50 × 50 mm, a plain weave mesh-like sheet body 20 (D = 45 μm) with an opening ratio of 76% (D = 45 μm) is provided near the main seal 30 on four sides. By providing every other row of discontinuous cuts (FIG. 5 (a)) or every other row of discontinuous cuts (FIG. 5 (b)), the stress relieving portion 25c is provided. Forming. The cut (slit) is a discontinuous cut, and is preferably half or more of the side length of the display surface, and is 45 mm in this embodiment. In addition, it is preferable that the notch 25c is 0 to 3 times the mesh pitch from the viewpoint of harmony with stress relaxation and aggregation prevention. Further, the distance between the substrates is 50 μm.
In the electrophoresis apparatus of the present embodiment, every other discontinuous cut (alternately) one row [FIG. 5 (a)], or every other discontinuous cut (alternate) two rows [alternate]. 5 (b)] is provided, the shape of the mesh itself is difficult to collapse, the opening (mesh portion) does not spread, and the effect of further suppressing the aggregation and uneven distribution of charged particles by the mesh portion is exhibited. .

FIG. 6 shows a fifth embodiment of the electrophoretic display device of the present invention and is a plan view of a mesh-like sheet body 20 made of a woven body.
Although the stress relaxation part 25d of this embodiment is comprised by forming a cut | notch part in the part displayed at least among the mesh-shaped sheet bodies 20 which consist of a textile body, specifically, FIG. As shown, it consists of a polyarylate fiber (fiber diameter d: 23 μm), a display portion 50 × 50 mm, and a plain weave mesh sheet 20 (D = 45 μm) with an opening ratio of 76%. A circular cut is continuously formed at the intersection where the vertical and horizontal fibers intersect. The cut (slit) is a continuous cut, and is preferably at least half the side length of the display surface, and is 56 mm in this embodiment. Further, the distance between the substrates is 50 μm.
In the electrophoresis apparatus of this embodiment, since it is punched into a circular shape, it is easy to process, the mesh misalignment is difficult to place, and the opening (mesh portion) does not spread, and the charged particles are aggregated or unevenly distributed by the mesh portion. Further, the suppressing effect is exhibited.

FIG. 7 shows a sixth embodiment of the electrophoretic display device of the present invention, and is a plan view of a mesh-like sheet body 20 made of a woven body.
Although the stress relaxation part 25e of this embodiment is comprised by forming a cut | notch part in the part displayed at least among the mesh shaped sheet | seat bodies 20 which consist of textiles, Specifically, in FIG. As shown, a polyarylate fiber (fiber diameter d: 23 μm), a display portion 50 × 50 mm, a plain weave mesh-like sheet body 20 (D = 45 μm) with an opening ratio of 76% (D = 45 μm) is provided near the main seal 30 on three sides. The U-shaped cuts are formed continuously. The cuts (slits) are continuous cuts, and are preferably half or more of the side length of the display surface. In this embodiment, each side is 40 mm. Further, the distance between the substrates is 50 μm.
In the electrophoresis apparatus of this embodiment, the effect which further suppresses aggregation and uneven distribution of the charged particles by a mesh part is exhibited.

FIG. 8 shows a seventh embodiment of the electrophoretic display device of the present invention, and is a plan view of a mesh sheet 20 made of a horizontally long woven fabric.
The stress relaxation portion 25f of the present embodiment is configured by forming a cut portion in at least a portion to be displayed in the mesh-like sheet body 20 made of a woven body. Specifically, FIG. As shown, it consists of a polyarylate fiber (fiber diameter d: 23 μm), a display portion 50 × 100 mm, and a plain weave mesh-like sheet body 20 (D = 45 μm) with an opening ratio of 76%. The incision is continuously formed. The incision (slit) is a continuous incision, and is preferably half or more of the side length of the display surface, and is 40 mm in this embodiment. Further, the distance between the substrates is 50 μm.
In the horizontally long electrophoresis apparatus of the present embodiment, it is a cut in one direction (longitudinal direction), is resistant to bending in the normal direction of the cut, and exhibits an effect of further suppressing aggregation and uneven distribution of charged particles by the mesh portion. It becomes. In the present embodiment, the longitudinal cuts are continuously formed every two width directions, but the cuts may be continuously formed every other width direction or every third. is there.

9 to 12 show another embodiment of the electrophoretic display device of the present invention, in which hot embossing, embossing (imprinting), laser is applied to a synthetic resin film made of a thermoplastic resin such as a PET film. This is each form of the mesh-like sheet body 20 in which holes of various shapes and stress relaxation portions are formed by processing or the like.
9 (a) and 9 (b) show a case where a slit made of a cut is formed as a stress relaxation portion 25g in at least a portion to be displayed of the mesh-like sheet body 20 in which a square hole is formed. It consists of a mesh-like sheet body 20 (D = 45 μm) made of PET film having a portion of 50 × 50 mm and an aperture ratio of about 80%, and slits are continuously formed in the vicinity of the main seals on the four sides. The cuts (slits) are continuous cuts, and are preferably half or more of the side length of the display surface. In this embodiment, each side is 30 mm. Further, the distance between the substrates is 50 μm.
10 (a) and 10 (b), at least a portion to be displayed in the mesh-like sheet body 20 in which a quadrangular hole is formed, a slit is formed by removing a side constituting the partition portion as the stress relaxation portion 25h. It consists of a mesh-like sheet 20 (D = 45 μm) made of PET film with a display area of 50 × 50 mm and an aperture ratio of about 80%. Each slit with a length of 30 mm is formed near the main seal on 4 sides. Has been. Further, the distance between the substrates is 50 μm.

11 (a) and 11 (b) show a case where a slit made of a cut is formed as a stress relaxation portion 25i in at least a portion to be displayed in the mesh-like sheet body 20 in which circular holes are formed. It consists of a mesh-like sheet body 20 (D = 45 μm) made of a PET film having a portion of 100 × 50 mm and an aperture ratio of about 80%, and slits are continuously formed in the vicinity of the main seal on two sides. The incision (slit) is a continuous incision and is preferably half or more of the side length of the display surface. In this embodiment, the long side is 60 mm and the short side is 20 mm. Further, the distance between the substrates is 50 μm.
12 (a) and 12 (b) show a case where a slit made of a cut is formed as a stress relaxation portion 25j in at least a portion to be displayed in the mesh-like sheet body 20 in which hexagonal holes are formed. This is made of a mesh sheet 20 (D = 45 μm) made of PET film having a portion of 60 × 70 mm and an aperture ratio of about 80%, and incisions are continuously formed in the vicinity of the main seal on two sides. The incision (slit) is a continuous incision and is preferably half or more of the side length of the display surface. In this embodiment, the long side is 50 mm and the short side is 50 mm. Further, the distance between the substrates is 50 μm.
In addition, the shape of a notch is not limited to the form of FIGS. 9-12, You may form each other notch detailed in detail in FIGS.

  Also in the electrophoretic display device of each embodiment shown in FIGS. 9 to 12 configured as described above, the mesh-like (mesh-like) sheet body 20 made of a synthetic resin film can be used to maintain an appropriate substrate interval and It is possible to prevent short-circuits due to contact, has an effect of suppressing aggregation and uneven distribution of charged particles, and stress applied externally by the stress relaxation parts 25g to 25j, curing of the adhesive used for bonding The sheet body 20 can be effectively expanded and contracted against the stress caused by the shrinkage, the shrinkage of the substrate, and the stress generated during the assembly, and the flexibility can be achieved without impairing the display quality and driving characteristics. In the electrophoretic display device having the same, it is possible to maintain a stable substrate gap (gap) corresponding to deformation, and to manufacture at a low cost.

The electrophoretic display device of the present invention is not limited to the above embodiment, and can be changed to various forms within the scope of the gist of the present invention.
For example, in the above embodiment, the mesh-like sheet body is composed of a woven body composed of fibers, a synthetic resin film composed of a thermoplastic resin, etc., for example, a non-woven body formed without interweaving fibers. A mesh-like sheet body may be used.
Nonwoven sheets formed without interweaving fibers are manufactured by methods such as wet nonwoven fabrics, dry nonwoven fabrics (chemical bonds, thermal bonds, air lays, etc.), spunlace methods, spunbonds, stitch bonds, etc. The nonwoven fabric sheet which was made is mentioned. In order to obtain a desired thickness or to maintain the shape of the nonwoven body, these nonwoven sheet bodies are subjected to secondary processing such as pressing treatment, adhesion treatment, and welding treatment in the same manner as the above-described textile body 20. May be performed.
Further, each partition portion is pressed with a microbit mold for forming holes having convex blades so as to form a partition portion having an arbitrary shape such as a circular shape, a quadrangular shape, a polygonal shape such as a hexagonal shape, or an elliptical shape. Can also be formed.
Also in the electrophoretic display device using these non-woven sheets, the stress relaxation portions can be the respective stress relaxation portions shown in FIG. 1 to FIG. An effect can be exhibited.

Next, the present invention will be described in more detail with reference to test examples (Examples and Comparative Examples), but the present invention is not limited to the following Examples.
An electrophoretic display device was obtained by the following method.

(Production of electrophoretic display device)
The electrophoretic display device according to FIG. 1 was obtained by the following steps.
1) Substrates 10 and 15 used
Front substrate 10: The surface resistance value is on the surface of an ITO-PET film having a thickness of 125 μm.
Substrate formed to be 300Ω / □ Rear substrate 15: A copper thin film is formed on a polyimide film substrate having a thickness of 400 μm,
A substrate on which a 7-segment pattern was formed by etching. Substrate spacing: 50 μm
2) Mesh sheet 20
From a polyarylate fiber (fiber diameter d: 23 μm) as shown in FIGS. 1A and 1B, a plain weave mesh sheet 20 (D = 45 μm) having a display area of 50 × 50 mm and an aperture ratio of 76%. Thus, in the vicinity of the main seal 30 on the four sides, the stress relaxation portion 25 is formed by providing a cut (slit) of 0.1 mm with a width not exceeding the opening width. The length of the cut (slit) is 40 mm on the side of the display surface.
3) Display solution for electrophoresis used Resin particles (particle size: about 0.3 μm) and carbon black colored with lipophilic titanium oxide (particle size: about 0.3 μm) as charged particles in xylene as an insulating liquid 1 μm) and an ink obtained by adding hydroxylaurylamine.

4) Fabrication of electrophoretic display device As shown in FIGS. 1 (a) and 1 (b), a UV curable adhesive was applied on the outer periphery of the back substrate, and then the electrode surface of the back substrate was used. 2) Place the sheet body 20 of the woven body of 2) above, fill the mesh portion of the sheet body 20 with the electrophoretic display liquid obtained in 3) above, cover the front plate, and then irradiate with UV light. Thus, an electrophoretic display device having a display portion of 50 mm × 50 mm and a seal portion width of 7 mm was produced.
On the other hand, as a comparative example, an electrophoretic display device having a display portion of 50 mm × 50 mm and a seal portion width of 7 mm was manufactured by using a mesh having no stress relaxation portion (notch) and manufacturing in the same manner as described above. .

The electrophoretic display devices of the obtained Examples and Comparative Examples were repeatedly subjected to deformation tests by the following method to evaluate the display performance.
(Repeated evaluation test method)
The seal part of the opposite side of the electrophoretic display device is fixed with a metal fixture so that the electrophoretic display device is not removed using a silicone rubber sheet as a cushioning material, and the curvature is R when viewed from the side. It was repeatedly deformed repeatedly 1000 times (500 times on one side) alternately on the front substrate side and the back substrate side so that = 100.

As a result of the 1000 times repeated deformation test, the comparative display sample was stirred and became non-uniform, and the twist of the mesh body was suppressed and the display deteriorated. Further, although a voltage was applied, the display quality was inferior, and reproduction was impossible even when a higher voltage was applied than usual.
On the other hand, it turned out that the example which becomes this invention can display favorable even after 1000 times of repeated deformation tests.

It is drawing which shows 1st Embodiment of the electrophoretic display device of this invention, (a) is a schematic sectional drawing of an electrophoretic display device, (b) is a top view. (A) is a partial exploded perspective view of the electrophoretic display device of the first embodiment, (b) is a partial plan view of a mesh sheet, and (c) is a cross-sectional view of the mesh sheet. FIG. 2 is a plan view of a mesh-like sheet body made of a woven body, showing a second embodiment of the electrophoretic display device of the present invention. 3 shows a third embodiment of the electrophoretic display device of the present invention, and is a plan view of a mesh-like sheet body made of a woven body. FIG. (A) And (b) shows 4th Embodiment of the electrophoretic display apparatus of this invention, (a) The top view of the mesh-like sheet body which consists of a textile body, (b) is the textile fabric which becomes another example It is a top view of the mesh-like sheet body which consists of a body. 5 is a plan view of a mesh-like sheet body made of a woven fabric, showing a fifth embodiment of the electrophoretic display device of the present invention. FIG. 6 is a plan view of a mesh-like sheet body made of a woven body, showing a sixth embodiment of the electrophoretic display device of the present invention. FIG. 7 is a plan view of a mesh-like sheet body made of a fabric body, showing a seventh embodiment of the electrophoretic display device of the present invention. FIG. (A) And (b) shows other embodiment of the electrophoretic display device of the present invention, and is a top view and a perspective view of a mesh-like sheet object which consists of synthetic resin films, respectively. (A) And (b) shows other embodiment of the electrophoretic display device of the present invention, and is a top view and a perspective view of a mesh-like sheet object which consists of synthetic resin films, respectively. (A) And (b) shows other embodiment of the electrophoretic display device of the present invention, and is a top view and a perspective view of a mesh-like sheet object which consists of synthetic resin films, respectively. (A) And (b) shows other embodiment of the electrophoretic display device of the present invention, and is a top view and a perspective view of a mesh-like sheet object which consists of synthetic resin films, respectively.

Explanation of symbols

A Electrophoretic Display Device 10 Substrate 15 Substrate 20 Mesh Sheet Sheet 36 Made of Textile Body Stress Relieving Unit 30 Sealing Material

Claims (3)

  A light transmissive substrate on which an electrode is formed; a substrate having an electrode disposed opposite to the substrate; and an electrophoretic display liquid comprising at least one kind of electrophoretic particles filled between the counter substrates; An electrophoretic display device in which a sealing portion that seals the display liquid between substrates and a mesh-like sheet member disposed between the opposing substrates, wherein at least a portion of the mesh-like sheet member that displays An electrophoretic display device comprising a stress relaxation portion that relaxes against stress.   The electrophoretic display device according to claim 1, wherein the stress relaxation portion includes a cut portion formed in at least a part of the mesh sheet.   3. The electrophoretic display device according to claim 1, wherein the mesh-like sheet body is formed of any one of a woven body formed of fibers, a non-woven body formed without weaving the fibers, and a film.

Images