JP2007171605A - Electrophoretic display medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophoretic display medium with high gap stability, which does not damage display quality and drive characteristics even in deformation, stably holds display, allows high contrast display and is manufactured conveniently at low costs. <P>SOLUTION: The electrophoretic display medium A is formed by arranging: a light transmissible substrate 10 on which an electrode is formed; a substrate 15 having an electrode arranged opposite to the substrate 10; liquid 20 for electrophoretic display containing at least one or more kinds of electrophoretic particles filled between the opposite substrates; a seal part 25 which seals the liquid 20 for display between the substrates 10 and 15 and arranging a layer comprised of fiber between the opposite substrates, wherein at least a part of the layer 30 comprised of fiber is fixed to the inside of the seal part 25. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrophoretic display medium capable of reversibly changing a visual state by the action of an electric field or the like.

  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 a low-potential material such as xylene, tetrachloroethylene, paraffin, or silicone oil 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.

Generally, as a required characteristic of a display medium using an externally responsive liquid including an electrophoretic method, it is necessary to keep the distance between the substrates arranged opposite to each other constant. For this reason, conventionally, a method has been adopted in which particles of resin or metal oxide are dispersed over the entire display surface to form spacers and are sandwiched between two opposing substrates. However, these methods have difficulty in processability and uniformity, and further, it is necessary to press the substrate against the counter substrate side in order to fix the spacer particle group. It has been difficult to produce a flexible display medium.
Further, conventionally, in the electrophoretic display medium, when display is repeated, there is a problem that display unevenness occurs due to aggregation or adhesion of electrophoretic particles, and the display deteriorates.
In order to solve these problems, a proposal has been made to reduce the deterioration of display by arranging a mesh-like thin film between opposing substrates and dividing the display liquid into discontinuous sections. This makes it difficult to display the display area. Furthermore, if it is completely discontinuous, there is a problem that the display liquid cannot be uniformly filled by a general vacuum filling method.

  As a specific method for creating the section, a printing method, an imprint method, a laser processing method, a dry film resist method, a lithography method, and the like are known. However, these methods have a problem in that it is very difficult to form a shape having a large gap and a thin dividing wall, that is, a shape having a so-called high aspect ratio. Further, the dry film resist method, the lithography method, and the laser processing method have low productivity, and the printing method generally has poor solvent resistance, and the display liquid type to be filled tends to be limited.

Furthermore, electrophoretic particles, dispersion medium, and the like are encapsulated in advance in a microcapsule, and an electrosimilar display medium in which these microcapsules are arranged between opposing substrates (for example, see Patent Documents 2 and 3), There is known an electrophoretic display medium in which an electrophoretic particle, a dispersion medium, or the like enclosed in a container is disposed between opposing substrates.
However, these electrophoretic display media have a complicated structure, and since the inclusion body is circular or spherical, a space is inevitably generated in the contact portion with the substrate. There is a problem in the easy point.

  Further, in the electrophoretic display medium, in order to keep the distance between the electrodes constant or to keep the thickness of the liquid for display constant, an obstruction made of an insulating porous layer, for example, a granular material, An electrophoretic display medium suitable for sheet-like display particularly suitable for flexibility, characterized by interposing a net-like material, a porous substance or the like in the display liquid (for example, Patent Documents 4 and 5). As shown in FIGS. 11 (a) and 11 (b), a natural or synthetic reticulate 2 such as silk, nylon, acrylic or polyester is disposed between the substrates 1 and 1 as the reticulate. An electrophoretic display medium is known. In particular, in Reference 4, in Example 1, as shown in FIG. 11 (c), two cellulose films and a 100 mesh tetron screen (mesh) as a substrate are adhered at the periphery to disperse the inside. In Example 2, as shown in FIG. 11 (d), the end portions 1a and 1a of the cellulose film 1 and 1 serving as a substrate are dissolved and bonded with acetone and 170 mesh is used. An electrophoretic display medium is described which is fixed to the cellulose films 1 and 1 so that the tetron mesh (net-like material) does not move. In addition, 3 in FIG. 11 is a seal part.

However, an electrophoretic display medium in which a blocking substance made of an insulating porous layer such as a mesh described in Patent Document 4 or 5 is interposed in a display liquid prevents the horizontal movement of the display liquid. Although it is relaxed, as shown in FIG. 11 (c), a 100 mesh Tetron screen 2 is simply adhered to the cellulose film 1, 1 in the periphery, or as shown in FIG. 11 (d), 170 mesh. The tetron mesh 2 is simply fixed to the cellulose films 1 and 1 so that the thickness of the display medium cannot be evenly arranged. Further, when the display medium is folded and used, the display liquid is still not used. There is a problem in that the thickness of the film tends to be non-uniform and there are many display irregularities.
US Pat. No. 3,612,758 (Claims, Examples, etc.) JP 2000-231126 A (Claims, Examples, etc.) JP 2000-32005 A (Claims, Examples, etc.) Japanese Patent Publication No. 50-15355 (Claims, Examples, FIG. 1 etc.) JP-A-2005-345573 (Claims, Examples, etc.)

  The present invention has been made in view of the above-described problems of the prior art, and is intended to solve this problem. In an electrophoretic display medium, the gap stability is high and display quality and driving characteristics are not impaired even when deformed, and display can be performed. An object of the present invention is to provide an electrophoretic display medium that can be stably held, enables high-contrast display, and can be manufactured easily and at low cost.

  As a result of intensive studies to solve the above-described conventional problems, the present inventors have found that a light-transmissive substrate on which an electrode is formed, a substrate having an electrode disposed opposite to the substrate, and the counter substrate An electrophoretic display liquid containing at least one kind of electrophoretic particles filled in between and a seal portion that seals the display liquid between the substrates, and is configured by fibers between the counter substrates. It is an electrophoretic display medium in which layers are arranged, and it is found that an electrophoretic display medium of the above-mentioned purpose can be obtained by fixing a part of the layer composed of the fibers in a seal portion, thereby completing the present invention. It came to.

That is, the present invention resides in the following (1) to (6).
(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 medium having a liquid and a seal portion that seals the display liquid between substrates, and a layer composed of fibers disposed between the opposing substrates, the layer composed of the fibers An electrophoretic display medium characterized in that at least a part of is fixed in the seal portion.
(2) The electrophoretic display medium according to (1), wherein the layer composed of fibers is composed of a woven fabric formed by weaving fibers.
(3) The electrophoretic display medium according to (1), wherein the layer composed of fibers is composed of a non-woven body formed without weaving the fibers together.
(4) The electric layer according to (1), wherein the layer composed of fibers fixes the fibers by at least one of pressing, bonding, and welding of the fibers constituting the layer. Electrophoretic display medium.
(5) The fiber according to any one of (1) to (4) above, wherein the fiber of the layer composed of the fiber is a composite fiber made of at least two kinds of materials having different softening temperatures. Electrophoretic display medium.
(6) The electrophoretic display medium according to (5), wherein the pressing treatment is performed by heating to a temperature equal to or lower than a softening temperature of a material having the highest softening temperature among materials constituting the composite fiber.

  According to the present invention, the gap stability is high, display quality and drive characteristics are not impaired even when deformed, the display can be stably maintained, high contrast display is possible, and simple and low An electrophoretic display medium 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 and 2 are diagrams showing an example (first embodiment) of an electrophoretic display medium according to the present invention. FIG. 1A is a schematic cross-sectional view of the electrophoretic display medium, and FIG. Fig. 2 is a plan view showing an example of a layer composed of fibers (a plain woven fabric body), (c) is a side view thereof, and Fig. 2 (a) is a portion showing a contact mode of a layer composed of fibers to a seal portion. FIG. 4B is an exploded perspective view, and FIG. 5B is a plan view showing a contact mode of a layer composed of fibers to a seal portion.
The electrophoretic display medium A according to the first embodiment includes a display member and a substrate between a substrate 10 on which a light-transmitting electrode 10a is formed and a substrate 15 on which an electrode 15a disposed opposite to the substrate 10 is formed. The electrophoretic display liquid 20 containing the electrophoretic particles is arranged, and the layer 30 made of fibers having a specific structure is arranged.

  As the substrate 10 on which the light transmissive electrode 10a is formed in the present embodiment, 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, or a sputtering method. It can be obtained by forming a film by vapor deposition or the like, and even if it is an opaque conductive material such as metal, the same effect can be obtained by forming a very thin film, but it is limited to this. is not.

Further, as the substrate 15 on which the electrode 15a disposed opposite to the substrate 10 on which the light-transmissive electrode 10a is formed, the same substrate as the substrate 10 on which the light-transmissive electrode 10a is formed is used. Alternatively, a non-light-transmitting substrate in which an electrode is formed on a substrate such as a resin film, a resin plate, glass, glass, ceramics, metal, paper, or wood can also be used.
These substrates 10 and 15 may be so-called solid electrodes in which electrodes are formed on the entire surface, or those having a pattern formed by a conventionally used method such as a photo etching method or a laser processing method. These can also be combined arbitrarily.
Furthermore, as the substrate 15 on which the electrode 15a is formed, a TFT (Thin Film Transistor) substrate used in liquid crystal or the like can be used, but is not limited thereto.

In the space where these substrates 10 and 15 are arranged to face each other, a layer 30 composed of the electrophoretic display liquid 20 and fibers is arranged.
In the present embodiment, the electrophoretic display liquid 20 to be used is not particularly limited as long as it contains at least one kind of electrophoretic particles, a dispersant, and a dispersion medium.
As the electrophoretic particles that can be used, for example, colored or colorless (white) inorganic pigment particles, organic pigment particles, polymer fine particles, and the like can be used, and these can be used alone (one type) or two or more types. It can be used by mixing. Moreover, the fine particle by which the lipophilic surface treatment was carried out may be sufficient. Preferably, those having an average particle diameter of 0.05 to 20 μm are used, and those having an average particle diameter of 0.1 to 10 μm are particularly preferable. The total content of these fine particles is preferably 3 to 50% by weight, more preferably 5 to 35% by weight, based on the total amount of the electrophoretic display liquid.

Examples of the dispersant that can be used include various commonly used dispersants, surfactants and polymer surfactants such as nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. Examples thereof include, but are not limited to, system surfactants and polymer surfactants. The content of these dispersants is appropriately determined depending on the electrophoretic particles and solvent type to be used, but may be contained so as to be 0.01 to 50.0% with respect to the total amount of the electrophoretic display liquid. More preferably, it is desirable to contain 1 to 30%.
Further, as the dispersion medium, for example, various types of media 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, carboxylate esters , Chlorinated paraffin, N, N-dibutyl-2-butoxy-5-tertioctylaniline, and the like, but are not limited thereto. The content of these dispersion mediums is appropriately determined depending on the electrophoretic particles and the type of dispersant used, but is preferably contained so as to be 25 to 85% with respect to the total amount of the electrophoretic display liquid. More preferably, it is 30 to 60%. In addition, various oil-soluble dyes can be dissolved and colored in the dispersion medium.

  In the present embodiment, as the layer 30 composed of fibers, for example, as shown in FIG. 1B, a fabric body 31 formed by weaving fibers or formed without weaving fibers described later. The non-woven body can be used. The woven body 31 can be constituted by, for example, a woven body 31 formed by interweaving and knitting so as to form innumerable partition portions 32, 32.

Examples of the fibers 31a that form the layer 30 composed of these fibers include polyester resins such as PET, polyarylate resins, polyacetal resins, acrylic resins, polyamide resins, polyurethane resins, and polyolefin resins. In addition, synthetic fibers such as polyvinyl resins, polycarbonate resins, polyether resins, and polyphenylene resins can be used, and animal-derived fibers such as wool and eyelashes can also be used. 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.
The fiber 31a may be a multi-core fiber called a multifilament, or a single-core fiber called a monofilament fiber, and the material of the fiber may be a composite material combining the above materials, or may be made of a plurality of materials. A composite fiber in which fibers are combined may be used. Further, when forming the woven body 31 and the non-woven body, fibers of a plurality of kinds of materials may be combined, warp and weft yarns of the woven body 31 may be made of different materials, or the above-described contents may be appropriately combined.

Furthermore, by using a fiber having a rough surface, when the electrophoretic display liquid 20 is contained in the layer 30 composed of the fiber, the fiber is colored in an approximate color of the ink and becomes inconspicuous at the time of display, The display quality on 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.

  The diameter (d) of the fiber 31a to be used is desirably thin from the viewpoint of various performances such as display characteristics and responsiveness, preferably 1 to 200 μm, more preferably 1 to 50 μm. Further, the cross-sectional shape of the fiber 31a is preferably a circular shape. By using a circular fiber, the contact area with the substrate 10 is reduced when the layer 30 composed of the fibers is sandwiched between the substrates. Thus, the display area can be increased.

Examples of the woven fabric 31 formed by weaving these fibers 31a include a plain weave, a diagonal weave, a satin weave, or a woven fabric composed of a combination thereof. The forming method is not particularly limited as long as the partition portions 32, 32,... Are formed, and the woven body can be formed by various union and knitting methods.
FIGS. 1B and 1C are a plan view and a side view when the woven body 31 is configured by plain weave. Further, as shown in FIGS. 3 (a) and 3 (b), the woven body 31 may be composed of a three-slice or four-slash woven structure, and as shown in FIG. You may comprise the textile organization of vermilion.
Preferably, it is desirable that the woven body 31 is composed of a plain weave from the viewpoint of smoothness and shape stability.
Moreover, in order to improve the stability of the shape of the textile body 31, you may perform secondary processes, such as a press process, an adhesion process, and a welding process, after the formation process of the textile body 31, or formation.

In the pressing process, the fibers 31a, 31a constituting the fabric 31 are processed by pressing, calendering, roller processing, or the like after the formation of the fabric 31 or after the formation. 31a... Are fixed to each other, and the woven body 31 having high shape stability is formed.
Note that the pressing amount (pressing length) at this time is preferably set to slightly exceed the desired thickness in consideration of the desired thickness or repulsion.

The above-mentioned adhesion treatment is performed in the process of forming the fabric body 31 or after the formation, and the fibers 31a, 31a... Constituting the fabric body 31 are bonded to each other with an epoxy adhesive, an acrylate adhesive, a polyurethane adhesive, and a vinyl acetate adhesive. The fibers 31a, 31a, etc. overlap each other using an adhesive such as an adhesive, a phenolic adhesive, a melamine adhesive, a urea adhesive, a synthetic rubber adhesive, a natural rubber adhesive, or a water-based adhesive. By applying the adhesive to at least one of the fibers 31a and bonding them, the fibers 31a, 31a,... Are fixed to each other, and the woven fabric 31 having a high shape stability is formed.
Note that the type of adhesive, application area, application mode, application amount, and the like can be suitably combined in consideration of the fiber material, aperture ratio, weaving, and the like. For example, polyethylene terephthalate (PET) is used as the fiber. In such a case, an acrylate adhesive can be used as the adhesive.

Further, in the above-described welding treatment, the fibers 31a, 31a,... Are welded to each other using welding means such as heating, ultrasonic welding, vibration welding, laser welding, and the like. 31a, 31a... Are fixed to each other, and the fabric body 31 having high shape stability is formed.
In the heating means, the fiber 31a constituting the fabric body 31 is heated to a temperature equal to or higher than the softening temperature of the fiber 31a to fix the fibers 31a, 31a... The fibers 31a constituting the fiber 31a are melted by ultrasonic heating to fix the fibers 31a, 31a, and the fibers 31a, 31a... Are fixed to each other. 31a, 31a... Are fixed to each other to form the fabric body 31 having high shape stability.
In order to further improve the stability of the shape, a pressing step may be performed while heating (including ultrasonic welding, vibration welding, laser welding) or after heating.
Further, in the case of using a composite fiber, the fibers 31a, 31a,... Are maintained while maintaining the shape of the fiber by heating and welding to a temperature below the softening point of the material having the highest softening point among the materials constituting the fiber. ... can be fixed together.

The number of partition portions 32 of the woven body 31 composed of these plain weave, oblique weave, satin weave, etc. is determined by the number of meshes (the number of fibers driven per inch), and each side length of each partition portion 32 is It is calculated from 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, by appropriately combining the fiber diameter (wire diameter, d) and the number of fibers to be driven, the woven body 31 composed of plain weave, oblique weave, satin weave, etc. having an arbitrary opening ratio and opening surface is appropriately selected. Can be set.
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.

In the present invention, the thickness t of the layer composed of fibers is a factor governing the distance between the opposing substrates in the electrophoretic display medium, and is preferably 300 μm or less, more preferably from the viewpoint of responsiveness and display performance. 10 to 100 μm is desirable.
Further, in the case of plain weave, oblique weaving, and satin weaving, the fiber diameter d is preferably based on 1/2 of the distance between the opposing substrates (the thickness t of the layer composed of fibers), for example, t = In the case of 2d, when pressed (pressed), the fiber diameter is not impaired until d ≦ t ≦ 2d, and the shape of the layer 30 composed of the fibers is maintained up to 2d ≦ t ≦ 3d, and is composed of fibers. The effect as the layer 30 can be maintained.

The aperture ratio a of the layer 30 composed of fibers is preferably 50% or more, more preferably 70 to 97%, from the viewpoint of obtaining clear display performance, that is, high contrast display. Further, the opening area of each partition 32 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 the electrophoretic display medium A of the present embodiment, a fabric body 31 obtained as a layer 30 composed of fibers is disposed in a space where the substrate 10 and the substrate 15 are disposed to face each other, and each partition portion of the fabric body 31 is disposed. The electrophoretic display liquid 20 is accommodated in 32 and the periphery of the space portion is sealed by the seal portion 25.
In the present invention, at least a part of the layer 30 composed of the fibers is fixed in the seal portions 25, 25, specifically, composed of fibers composed of the plain weave, the oblique weave, the satin weave, or the like. The peripheral end 30a of the layer 30 is embedded in the seal portion 25, and in this embodiment, as shown in FIGS. 2A and 2B, a thermosetting adhesive that constitutes the seal portion on the substrate 15, UV Apply an adhesive such as a curable adhesive, an anaerobic curable adhesive, a natural curable adhesive, or a two-component mixed (chemical reaction curable) adhesive around the display, and then cure the adhesive. The seal portion is formed, and the peripheral end 30 a of the layer 30 made of fibers 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 20 such as an electrophoretic display liquid. In this space, the substrates 10 and 15 and the fabric body 31 are contained. Of the fibers 31a, 31a... Are not intersecting with each other, there is a gap in the surface direction, and each partition 32, 32... Even with a vacuum filling method or the like, uniform filling is possible.

In the electrophoretic display medium A of the present embodiment configured as described above, the fabric body 31 is disposed as a layer 30 composed of fibers between the opposing substrate 10 and the substrate 15, and the peripheral end 30 a is a sealing portion. 25, it is possible to obtain a uniform gap over the entire display surface of the image display medium, and the display medium is deformed when a flexible substrate such as a resin substrate is selected in addition to the normal state. As a result, an electrophoretic display medium having stable display quality and driving characteristics can be obtained.
Further, since the contact area between the fabric body 31 and the substrate 10 on which the transparent electrode 10a is formed is small, a wide surface + display surface is obtained. Further, electrophoresis is performed from the gaps in the surface direction between the substrates 10 and 15 and the fabric body. An electrophoretic display medium that can be uniformly filled with a display liquid is obtained.

Fig.5 (a)-(c) is an example of the nonwoven fabric formed without interweaving fibers as the layer 30 comprised from a fiber, (a) is piled up without interweaving fibers. The electrophoretic display medium according to the second embodiment, which is a non-woven body 33 in which the partition portions 32 are formed side by side and the peripheral end of the non-woven body 33 is fixed in the seal portion 25, as in the first embodiment. It is shown. The same configurations as those of the electrophoretic display medium A of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted (the same applies to the following embodiments).
Furthermore, as the fiber 31a to be used, a composite fiber having at least a two-layer structure and having the same or different melting points in each layer may be used. For example, as shown in FIG. 5 (c), a core part 31a1 and a sheath part 31a2 are provided. A composite fiber having a core-sheath structure having a low melting point (softening point) of the sheath may be used.
Moreover, FIG.5 (b) is the nonwoven fabric 34 which has arrange | positioned so that fibers might not overlap, and also the fibers may not overlap, and the division part 32 was formed. In FIG. 5B, since the flow path can be made larger than in other arrangements, it can be easily filled even when the viscosity of the display material is high or the contained migrating particles are large. .

6 (a) and 6 (b) show a case in which a layer 30 composed of fibers is composed of a non-woven body 35 that is formed without weaving the fibers together. An electrophoretic display medium according to a third embodiment in which the peripheral end of a woven body 35 is fixed in a seal portion 25 is shown.
The non-woven body 35 formed without weaving the fibers is manufactured by a manufacturing method such as a wet nonwoven fabric, a dry nonwoven fabric (chemical bond, thermal bond, air lay, etc.), a spunlace method, a spunbond, and a stitchbond. Nonwoven sheet may be mentioned. In order to obtain a desired thickness or maintain the shape of the non-woven body, these non-woven bodies 35 are subjected to secondary processing such as pressing, bonding, and welding in the same manner as the above-described woven body 31. May be.
Furthermore, pressing each other with a microbit mold for forming holes having convex blades so as to form a partition having an arbitrary shape, thereby forming each partition 32, 32... As shown in FIG. You can also.

In the electrophoretic display medium of FIG. 5 and the electrophoretic display medium using the non-woven body 35 of FIG. 6 which are these embodiments, a uniform gap can be obtained over the entire display surface of the electrophoretic display medium. In addition to the normal state, when a flexible substrate such as a resin substrate is selected, the gap can be maintained even if the display medium is deformed. As a result, an electrophoretic display medium with stable display quality and driving characteristics can be obtained. Obtainable.
Furthermore, since the contact area between the fabric body 31 and the substrate 10 on which the transparent electrode 10a is formed is small, a wide display surface can be obtained. Further, for electrophoretic display from the gaps in the surface direction between the substrates 10 and 15 and the fabric body. An electrophoretic display medium that can be uniformly filled with a liquid is obtained.

7 and 8 are each a cross-sectional view of an electrophoretic display medium showing a specific embodiment of the present invention.
The electrophoretic display medium of FIG. 7A includes a substrate (ITO-PET film) 10 on which a light-transmitting electrode is formed, and a substrate 15 [display pattern on which an electrode disposed opposite to the substrate 10 is formed. Between the glass epoxy substrate (FR-4 specification) formed with the electrophoretic display liquid 20 including electrophoretic particles serving as a display member, and a layer 30 made of fibers made of plain weave. The peripheral end 30a is fixed inside the seal portion 25 made of a UV curable adhesive.
In the electrophoretic display medium of FIG. 7 (b), a display pattern was formed with an electrolytic NiAu layer and a copper foil layer (18 μm) on a polyimide film (25 μm) on a substrate 15 on which a light-transmitting electrode was formed. This is different from FIG. 7A in that a substrate is used.
The electrophoretic display medium of FIG. 8A is formed on the entire seal portion 25 of FIG. 7A in that the peripheral end 30a of the layer 30 made of plain weave fibers is fixed to a part of the seal portion 25. It is different from the fixed one. Further, the electrophoretic display medium of FIG. 8B has the seal portion 25 of FIG. 7B in that the peripheral end 30a of the layer 30 made of plain weave is fixed to a part of the seal portion 25. It is different from the one fixed to the whole.
Each of the electrophoretic display media (a) and (b) in FIGS. 7 and 8 has high gap stability and does not impair display quality and drive characteristics even when deformed, and can stably maintain display. In addition, high-contrast display is possible, and it can be manufactured easily and at low cost.

On the other hand, FIG. 9 is each cross-sectional view showing an electrophoretic display medium that is outside the scope of the present invention.
The electrophoretic display medium of FIG. 9 (a) is formed on the entire inside of the seal portion 25 of FIG. 7 (a) in that the peripheral end 30a of the layer 30 made of plain weave fibers is fixed to the inner wall surface portion of the seal portion 25. It is different from the fixed one. The electrophoretic display medium of FIG. 9 (b) is formed on the entire inside of the seal portion 25 of FIG. 7 (b) in that the peripheral end 30a of the layer 30 made of plain weave fibers is fixed to the inner wall surface portion of the seal portion 25. It is different from the fixed one.
In these electrophoretic display media, as shown in FIGS. 9 (a) and 9 (b), the thickness of the display medium cannot be arranged uniformly, and further, when the display medium is bent and used, etc. Still, the thickness of the liquid for display tends to be non-uniform, and there are problems in that there are many display irregularities.

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 medium was obtained by the following method.

(A layer composed of fibers is formed of a woven fabric)
An electrophoretic display medium was obtained by the following steps.
1) Layer 30 composed of fibers (2 types)
A. Used fiber: Material: Polyarylate
Fiber diameter (d): 23 μm
Layer specification: plain woven fabric (low pressure roller press treatment)
Thickness 50μm
Opening ratio (a): 79%
B. Used fiber: Material: Polyester
Fiber diameter (d): 160 μm
Layer specification: plain woven fabric (low pressure roller press treatment)
Thickness 300μm
Opening ratio (a): 50%

2) 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,
Substrates on which a 7-segment pattern was formed by an etching method 3) Electrophoretic display solution used Xylene was colored with xenophilic titanium oxide (particle size: about 0.3 μm) and carbon black An ink obtained by adding resin particles (particle size: about 1 μm) and hydroxylaurylamine.

4) Production of electrophoretic display medium (two types with or without electrophoretic display liquid filling) As shown in FIG. 7B, an acrylate UV curable adhesive is applied to the three sides of the back substrate 15 as seal portions 25. Then, each of the fabric bodies 31 is placed, the peripheral edge is placed in the adhesive layer, and the front substrate 10 is further placed thereon, and the fabric body 31 is held between the substrates 10 and 15 with UV. Irradiated with light, the fabric 31 and the counter substrates 10 and 15 were integrated to produce an electrophoretic display medium not filled with an electrophoretic display liquid. In addition, after filling the electrophoretic display medium obtained above with an electrophoretic display liquid having the following composition by a vacuum filling method, the opened filling holes are sealed with an acrylate-based UV curable adhesive, and each electrophoretic display medium is sealed. An electrophoretic display medium was obtained.
On the other hand, as shown in FIG. 9B, an acrylate-based UV curable adhesive is applied to the three sides of the back substrate 15 as the seal portion 25, and the fabric bodies 31 are placed thereon. Further, the front substrate 10 is placed thereon, and the fabric body 31 is sandwiched between the substrates 10 and 15 and irradiated with UV light, so that the fabric body 31 and the opposing substrates 10 and 15 are bonded to each other. An electrophoretic display medium that was integrated and not filled with the electrophoretic display liquid was obtained. In addition, after filling the electrophoretic display medium obtained above with an electrophoretic display solution by a vacuum filling method, the opened filling holes are sealed with an acrylate UV curable adhesive, and each electrophoretic display medium is sealed. Got.

(Liquid composition for electrophoretic display)
Obtained by adding oleophilic titanium oxide (average particle size of about 0.3 μm), resin particles colored with carbon black (average particle size of about 0.1 μm), and hydroxylaurylamine in xylene Electrophoresis display solution.

For each electrophoretic display medium that is unfilled or filled with the obtained electrophoretic display liquid, as shown in FIGS. 10A and 10B, the display surfaces 1 to 4 of each electrophoretic display medium, The thickness of 1 and 2 on the main seal is measured with a thickness gauge [manufactured by Teclock, pressure during measurement: 80 g, shape of measuring terminal (anvil): plane circular diameter 10 mm], and uniformity is evaluated according to the following evaluation criteria. went. These results are shown in Tables 1 and 2 below.
Evaluation criteria:
○: The thickness is uniform and display uniformity can be expected.
Δ: Thickness is uneven and operation is performed, but display uniformity cannot be expected.
X: Thickness is remarkably uneven, and operation / display itself cannot be expected.

Further, the display performance of the electrophoretic display medium was evaluated by the following evaluation method for each electrophoretic display medium filled with the electrophoretic display liquid obtained above.
Next, a desired voltage (50 V) was applied to each electrophoretic display medium obtained above, and the display performance of the electrophoretic display medium was evaluated according to the following evaluation criteria.
These results are shown in Table 2 below.
Evaluation criteria:
A: High contrast black and white display and excellent display performance.
○: Recognizable black and white display.
Δ: Although it operates, it is difficult to identify due to uneven display and blurring.
×: Cannot be displayed without operation.

上記表１及び表２の結果から明らかなように、本発明となる電気泳動表示媒体は、本発明範囲外となる電気泳動表示媒体に較べ、表示媒体の厚みを均一に配置することができ、ギャップ安定性が高く変形時も表示品位や駆動特性を損なうことがなく、表示を安定的に保持することができることが判明した。また、高コントラスト表示を可能とし、しかも、簡便かつ低コストで製造できる電気泳動表示媒体であるものであった。

As is clear from the results of Tables 1 and 2, the electrophoretic display medium according to the present invention can be arranged with a uniform thickness of the display medium as compared to the electrophoretic display medium that is outside the scope of the present invention. It has been found that the gap stability is high and the display quality and driving characteristics are not impaired even during deformation, and the display can be stably maintained. Further, it is an electrophoretic display medium that enables high-contrast display and can be manufactured easily and at low cost.

(A) is schematic sectional drawing of the electrophoretic display medium which shows 1st Embodiment of this invention, (b) The top view which shows an example in which the textile body which comprises the layer comprised from a fiber comprises a plain weave, (c) ) Is a side view thereof. (A) is a partial exploded perspective view which shows the adhering aspect to the seal part of the layer comprised from a fiber, (b) is a top view which shows the adhering aspect to the seal part of the layer comprised from a fiber. (A) is a plan view showing an example in which a woven body constituting a layer composed of fibers is composed of three oblique weaves, (b) is a four-sided woven body constituting a layer composed of fibers. It is a top view which shows an example comprised from sentence weaving. It is a top view which shows an example in which the textile body which comprises the layer comprised from a fiber is comprised from a five sheet satin (vertical satin) weave. It is an electrophoretic display medium which shows 2nd Embodiment of this invention, (a) is an expanded perspective view which shows an example of the nonwoven fabric which comprises the layer comprised from a fiber, (c) is the core used for a nonwoven fabric It is sectional drawing of the composite fiber of a sheath structure. (A) shows the electrophoretic display medium which shows 3rd Embodiment of this invention, (a) is a top view which shows the other example of the nonwoven fabric which comprises the layer comprised from a fiber, (c). Is a side view thereof. (A) is a cross-sectional view showing an example of a specific embodiment of the electrophoretic display medium of the present invention, and (b) is a cross-sectional view showing another example of the specific embodiment of the electrophoretic display medium. (A) is a cross-sectional view showing another example of the specific embodiment of the electrophoretic display medium of the present invention, (b) is a cross-sectional view showing another example of the specific embodiment of the electrophoretic display medium. (A) is a cross-sectional view showing an example of the electrophoretic display medium outside the scope of the present invention, and (b) is a cross-sectional view showing another example of the electrophoretic display medium outside the scope of the present invention. (A) is a cross-sectional view showing an example of the electrophoretic display medium outside the scope of the present invention, and (b) is a cross-sectional view showing another example of the electrophoretic display medium outside the scope of the present invention. (A) is a cross-sectional view showing an example of an electrophoretic display medium outside the scope of the present invention, (b) is a plan view thereof, and (c) and (d) are described in Japanese Patent Publication No. 50-15355. 3 is a cross-sectional view of each of the electrophoretic display media of Examples 1 and 2. FIG.

Explanation of symbols

A Electrophoretic display medium 10 Substrate 10a Electrode 15 Substrate 20 Liquid for electrophoretic display 25 Seal part 30 Layer 31 composed of fibers 32 Fabric body 32 Partition part 33 Non-woven body 34 Non-woven body

Claims (6)

  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 medium in which a sealing portion for sealing the display liquid between substrates and a layer composed of fibers between the counter substrates are arranged, and at least a part of the layer composed of the fibers is sealed An electrophoretic display medium, characterized in that it is fixed in a part.   2. The electrophoretic display medium according to claim 1, wherein the layer composed of fibers is composed of a woven fabric formed by weaving the fibers.   2. The electrophoretic display medium according to claim 1, wherein the layer composed of fibers is composed of a non-woven body formed without weaving the fibers.   The electrophoretic display medium according to claim 1, wherein the layer composed of the fibers fixes the fibers by at least one of pressing, bonding, and welding of the fibers constituting the layer.   The electrophoretic display medium according to any one of claims 1 to 4, wherein the fiber of the layer composed of fibers is a composite fiber made of at least two kinds of materials having different softening temperatures.   The electrophoretic display medium according to claim 5, wherein the pressing process is performed by heating to a temperature equal to or lower than a softening temperature of a material having the highest softening temperature among materials constituting the composite fiber.

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