JP2006058544A - Panel for picture display and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a panel for picture display, for which a step to remove a picture display medium is eliminated by arranging a partition wall with a shape placing no picture display medium on the top of one substrate and arranging a recessed part to fit the partition wall on the other substrate, and which is excellent in display picture quality and low-cost, and a method for manufacturing the same. <P>SOLUTION: In the panel for picture display, which displays a picture by forming a plurality of cells partitioned with partition walls 4 between the two substrates 1, 2 of which at least one is transparent and which are placed opposite to each other, sealing the picture display media 3W, 3B in the cells, and moving the picture display media by applying an electric field to the picture display media, the partition walls 4 with a shape tapering only on the tip part is arranged on the transparent substrate 1 as the partition walls arranged to form the cells to seal the picture display media by partitioning, and the recessed part 12 to which the tapered part of the end part of the partition wall is fit is arranged on the other substrate 2, and two substrates are superposed to each other so as to fit the partition wall 4 and the recessed part 12. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention forms a plurality of cells partitioned by a partition between two opposing substrates at least one of which is transparent, encloses an image display medium in the cells, and applies an electric field to the image display medium. The present invention relates to an image display panel that moves an image display medium to display an image, a manufacturing method thereof, and an image display device equipped with the image display panel.

  Conventionally, image display devices using techniques such as electrophoresis, toner (particle) transfer, electrochromic, thermal, and two-color particle rotation have been proposed as image display devices that replace liquid crystal (LCD). Yes.

  Compared with LCD, these conventional technologies have advantages such as a wide viewing angle close to that of ordinary printed materials, low power consumption, and a memory function. It is considered as a technology that can be used for mobile phones, and is expected to expand to image display for portable terminals, electronic paper, and the like. In particular, recently, an electrophoretic method (for example, see Non-Patent Document 1) in which a dispersion liquid composed of dispersion particles and a colored solution is microencapsulated and disposed between opposing substrates has been proposed and expected. It has been.

  However, the electrophoresis method has a problem that the response speed becomes slow due to the viscous resistance of the liquid because the particles migrate in the liquid. Furthermore, since particles with high specific gravity such as titanium oxide are dispersed in a solution with low specific gravity, it is easy to settle, and it is difficult to maintain the stability of the dispersed state, and there is a problem of lack of image repetition stability. . Even when microencapsulation is performed, the cell size is set to the microcapsule level, and the above-described drawbacks are hardly made to appear, and the essential problems are not solved at all.

  On the other hand, a method in which conductive particles and a charge transport layer are incorporated into a part of a substrate without using a solution is proposed instead of an electrophoresis method using behavior in a solution (see, for example, Non-Patent Document 1). ). However, this method has a problem that the structure is complicated because the charge transport layer and further the charge generation layer are arranged, and that it is difficult to inject the charges into the conductive particles, so that the stability is lacking. .

  As one method for solving the various problems described above, a plurality of cells partitioned by a partition are formed between two opposing substrates at least one of which is transparent, and an image display medium is sealed in the cells. An image display device equipped with an image display panel that displays an image by moving an image display medium by applying an electric field to the image display medium is known. In such an image display panel, when an image display medium is sealed in a small room (cell) surrounded by a partition wall, the image display medium is filled in the cell before the substrates are overlaid. At this time, since the image display medium adheres and accumulates on the top portion of the partition wall defining the cell, an attempt has been made to prevent the image display medium from attaching to the top by tapering the partition wall.

趙 Kuniori and three others, “New Toner Display Device (I)”, July 21, 1999, Annual Meeting of the Imaging Society of Japan (83 times in total) “Japan Hardcopy’99”, p.249-252

  However, when the entire partition wall is tapered, a gradient is formed in the partition wall portion exposed in the cell. Therefore, when the image display medium moves between the substrates, the gradient of the partition wall is the moving direction of the image display medium. On the other hand, the image display medium becomes easy to move in the forward direction, and the image display medium becomes difficult to move in the reverse direction, so that the stability of the image display quality is impaired. In addition, when the entire partition wall is tapered, the area of the bonded portion between the partition wall and the substrate is small, so that sufficient bonding strength cannot be obtained.

  The present invention provides a display image in which an image display medium removal step is not required by providing a partition having a shape in which the image display medium does not ride on the top on one substrate and providing a recess for fitting the partition on the other substrate. An object of the present invention is to provide an inexpensive image display panel having excellent quality and a method for manufacturing the panel.

  In order to achieve the above object, an image display panel according to the present invention has a plurality of cells formed by partition walls between two opposing substrates, at least one of which is transparent, and an image display medium is provided in the cells. An image display panel for displaying an image by moving the image display medium by enclosing and applying an electric field to the image display medium, and as a partition provided to define the cell enclosing the image display medium A partition wall having a tapered shape only at the front end portion is provided on a transparent substrate, and a concave portion in which the tapered shape portion of the front end portion of the partition wall is fitted is provided on the other substrate, and the two substrates are divided into a partition wall and a concave portion. It is characterized by overlapping so as to fit.

  As a preferred example of the image display panel of the present invention, the tapered shape of the partition wall tip is provided in any one of a tent tension shape, a triangle shape, a semicircular shape, and a semielliptical shape in a longitudinal cross-sectional shape. The relationship between the height H1 of the tapered portion at the tip of the partition wall in the length direction and the depth H2 of the recess provided in the counterpart substrate is such that H1 ≦ H2, and the image The display medium may be a particle group or a powder fluid.

  In order to achieve the above object, according to the method for manufacturing an image display panel of the present invention, a plurality of cells partitioned by a partition are formed between two opposing substrates, at least one of which is transparent, and an image is formed in the cell. An image display panel manufacturing method for encapsulating a display medium and moving an image display medium to display an image by applying an electric field to the image display medium, wherein the cell enclosing the image display medium is defined. As a partition wall provided for the purpose, a partition wall having a tapered shape only at the tip portion is provided on a transparent substrate, and a concave portion into which the tapered shape portion at the tip end of the partition wall is fitted is provided on the other substrate. After the image display medium is filled on the side, the two substrates are overlapped so that the partition wall and the recess are fitted.

  As a preferred example of the method for manufacturing an image display panel according to the present invention, the tapered shape of the partition wall tip is provided in any one of a tent tension shape, a triangle shape, a semicircular shape, and a semi-elliptical shape in a longitudinal cross-sectional shape. The relationship between the height H1 in the length direction of the tapered portion at the tip of the partition wall and the depth H2 of the recess provided in the counterpart substrate is such that H1 ≦ H2. The image display medium may be a particle group or a powder fluid.

The image display device of the present invention is configured to mount the image display panel according to any one of claims 1 to 4.
The image display device of the present invention is configured to mount an image display panel manufactured by the method for manufacturing an image display panel according to any one of claims 5 to 8.

  According to the image display panel of the present invention, a plurality of cells partitioned by a partition are formed between two opposing substrates, at least one of which is transparent, and an image display medium is sealed in the cells. In an image display panel that displays an image by moving an image display medium by applying an electric field to the display medium, only the tip is tapered as a partition provided to define the cell enclosing the image display medium A partition having a partition is provided on a transparent substrate, and the other substrate is provided with a recess for fitting the tapered portion of the tip of the partition, and the two substrates are stacked so that the partition and the recess are fitted. Therefore, the image display medium removal step is not performed because a partition having a shape that does not place the image display medium on the top is provided on one substrate, and a recess for fitting the partition is provided on the other substrate. Sufficient bonding strength because obtained between the partition and the substrate together becomes, it is possible to provide an inexpensive image display panel with excellent display image quality.

  According to the method for manufacturing an image display panel of the present invention, a plurality of cells partitioned by partition walls are formed between two opposing substrates, at least one of which is transparent, and an image display medium is sealed in the cells. An image display panel manufacturing method for displaying an image by moving the image display medium by applying an electric field to the image display medium, the partition provided for defining the cell enclosing the image display medium A partition having a tapered shape only at the tip is provided on a transparent substrate, and a recess is provided on the other substrate to which the tapered shape at the tip of the partition is fitted, and an image display medium is provided on the substrate provided with the partition. After filling the two substrates, the two substrates are overlapped so that the partition wall and the recess are fitted, so that a partition wall having a shape on which the image display medium does not ride is provided on one substrate, and the partition wall is fitted. Do The part is provided on the other substrate, so that the image display medium removal step is not necessary and sufficient bonding strength is obtained between the partition wall and the substrate, so that an inexpensive image display panel with excellent display image quality can be manufactured. A method can be provided.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  First, the configuration of the image display panel of the image display apparatus of the present invention will be described. In the image display device of the present invention, an electric field is applied by some means in the substrate of the image display panel in which the image display medium is sealed between the opposing substrates. The image display medium charged according to the electric field direction is attracted by an electric field force or a Coulomb force, and the image display medium is reciprocated by switching the electric field direction, thereby displaying an image. Therefore, it is necessary to design the image display panel so that the image display medium moves uniformly and can maintain stability during repetition or storage. Here, for example, the force applied to the particles or powder fluid used for the image display medium is not only the force attracted by the Coulomb force between the particles or powder fluid, but also the electric image force with the electrode, intermolecular force, liquid crosslinking force, Gravity is considered.

An example of an image display panel used in the image display device of the present invention will be described with reference to FIGS.
In the example shown in FIG. 1, two or more different types of particles 3 (here, white particles 3W and black particles 3B are shown) are connected to the substrates 1 and 2 according to the electric field applied from the outside of the substrates 1 and 2. The black particles 3B are moved vertically and the observer visually recognizes the black particles 3B, or the white particles 3W are visually recognized by the observer. In the example shown in FIG. 1, partition walls 4 are provided between the substrates 1 and 2, for example, in a lattice shape to define display cells.
In the example shown in FIG. 2, two or more kinds of particles 3 having different colors (here, white particles 3W and black particles 3B are shown) are placed between the electrode 5 provided on the substrate 1 and the electrode 6 provided on the substrate 2. Depending on the electric field generated by applying a voltage, the substrate is moved perpendicularly to the substrates 1 and 2 so that the black particles 3B are visually recognized by the observer, or black is displayed, or the white particles 3W are visually recognized by the observer. To display a white color. In the example shown in FIG. 2, partition walls 4 are provided between the substrates 1 and 2, for example, in a lattice shape to define display cells.
In the example shown in FIG. 3, according to the electric field generated by applying a voltage between the electrode 5 and the electrode 6 provided on the substrate 1, one kind of color particle 3 (here, white particle 3W). The white particles 3W are moved in the direction parallel to the substrates 1 and 2 and the white particles 3W are visually recognized by the observer, or the color of the electrode 6 or the substrate 1 is visually recognized by the observer. The color is displayed. In the example shown in FIG. 3, for example, a partition 4 is provided between the substrates 1 and 2 in a lattice shape to define a display cell.
The above description can be similarly applied to the case where the white particles 3W are replaced with the white powder fluid and the black particles 3B are replaced with the black powder fluid.

Hereinafter, a method for manufacturing an image display panel, which is a feature of the present invention, will be described in detail with reference to FIGS. 4 (a) to 4 (d) and FIGS. 5 (a) to 5 (c).
When the image display panel of the present invention is manufactured, first, as shown in FIG. 4A, one substrate (observer) on which a partition wall 4 having a tapered shape with only a tip portion sharpened is formed. The white image display medium 3W that is positively charged is sprayed from the upper side of the transparent substrate 1) by the spray nozzle 11 and is formed in the cells formed on the substrate by the partition walls 4 as shown in FIG. The white image display medium 3W is filled. Next, as shown in FIG. 4C, the negatively chargeable black image display medium 3B is sprayed by the spray nozzle 11 from above the substrate 1 after the filling of the white image display medium 3W is completed. ), The black image display medium 3 </ b> B is filled into the cells formed on the substrate by the partition walls 4.

Next, as shown in FIGS. 5 (a) and 5 (b), instead of forming a partition, a recess 12 that fits with the partition is formed, and a gap spacer 13 is provided in the periphery to secure a distance between the substrates. The other substrate (rear substrate) 2 that has been placed is overlaid on the substrate 1 after the filling of the white image display medium 3W and the black image display medium 3B, so that the partition wall 4 is fitted into the recess 12. Arrange and bond the two substrates together. At this time, even if there is some image display medium attached to the top of the partition wall, it is accommodated together with the tip of the partition wall 4 in the recess 12 provided on the rear substrate, so that the dispersed image display medium is somewhat placed on the top of the partition wall. However, it is possible to superimpose the two substrates without removing them. FIG. 5A shows a fitting state when no electrode is provided on the substrate, and FIG. 5B shows a fitting state when an electrode is provided on the substrate.
When the image display panel manufactured as described above visually recognizes an image from the transparent substrate 1 side, which is a substrate provided with a partition wall, according to the drive voltage applied between the electrodes, for example, as shown in FIG. The white image display medium 3W is aligned on the electrode 5 side close to the observer, and the black image display medium 3B is aligned on the electrode 6 side far from the observer.

  In the above, the depth of the concave portion 12 formed in the substrate 2 is set to be larger than the height of the tapered portion at the tip of the partition wall 4, so that the gradient of the tapered portion at the tip of the partition wall 4 is increased. It is preferable not to protrude into the cell. For this purpose, for example, as shown in FIG. 5, there is a relationship between the height H1 of the tapered portion at the tip of the partition wall 4 in the length direction and the depth H2 of the recess 12 provided in the substrate 2. H1 ≦ H2 so that the sharply tapered portion of the tip of the partition wall 4 is completely accommodated in the recess 12.

As the partition wall 4 in which only the tip portion formed on the transparent substrate 1 has a tapered shape, in addition to the longitudinal sectional shape (tent tension shape) shown in FIGS. 5 (a) to 5 (c), FIGS. 6 (a) to 6 (c). It is preferable to use one having a shape of any of a triangle shown in FIG. 7, a semicircle shown in FIGS. 7A to 7C, or a semi-elliptical shape (not shown).
The tapered shape of the partition wall 4 (tent tension, triangle, semi-circle, semi-elliptical shape) is more effective than preventing the image display medium from adhering to the top of the partition wall as compared with the case where the entire partition wall is tapered. However, by applying an appropriate vibration to the substrate when the image display medium is dispersed, a sufficient effect of preventing adhesion of the image display medium can be obtained by a synergistic effect with the tapered shape of the tip of the partition wall.

  According to the present invention, a partition wall 4 having a tapered shape only at the tip is provided on the transparent substrate 1 as a partition wall provided for defining a cell enclosing the image display medium, and the rear substrate 2 which is the other substrate is provided on the rear substrate 2. Since the concave portion 12 in which the tapered portion at the tip of the partition wall is fitted is provided and the two substrates are overlapped so that the partition wall and the concave portion are fitted, the image display medium does not adhere to the top of the partition wall. Since the “step of removing the image display medium on the top of the partition wall” is not necessary, an inexpensive image display panel excellent in display image quality and a method for manufacturing the panel can be provided. Further, since the partition wall 4 having a tapered shape only at the tip formed on the transparent substrate 1 is configured to fit into the recess 12 provided on the back substrate 2, no gradient is formed in the partition wall exposed in the cell, When the image display medium moves between the substrates, there is no forward gradient / reverse gradient with respect to the partition walls, and the area of the joint portion between the partition walls and the substrate is increased to obtain a sufficient bonding strength. Therefore, it is possible to provide an inexpensive image display panel excellent in display image quality and a manufacturing method thereof.

  Hereinafter, each member which comprises the image display panel of the image display apparatus used as the object of the present invention will be described.

  Regarding the substrate, at least one of the substrates is a transparent substrate from which the color of the image display medium can be confirmed from the outside of the apparatus, and a material having high visible light transmittance and good heat resistance is preferable. The back substrate as the other substrate may be transparent or opaque. Examples of substrate materials include polymer sheets such as polyethylene terephthalate, polyethersulfone, polyethylene, polycarbonate, polyimide, and acrylic, flexible materials such as metal sheets, and flexible materials such as glass and quartz. There are no inorganic sheets. The thickness of the substrate is preferably from 2 to 5000 μm, more preferably from 5 to 2000 μm. If it is too thin, it will be difficult to maintain the strength and the uniform spacing between the substrates, and if it is thicker than 5000 μm, a thin image display device will be obtained. There is an inconvenience.

  Electrode forming materials for the electrodes 5 and 6 provided as necessary include metals such as aluminum, silver, nickel, copper, and gold, and transparent conductive metal oxides such as ITO, indium oxide, conductive tin oxide, and conductive zinc oxide. Examples thereof include conductive polymers such as substances, polyaniline, polypyrrole and polythiophene, which are appropriately selected and used. As a method for forming an electrode, a method of forming the above-described materials into a thin film by sputtering, vacuum deposition, CVD (chemical vapor deposition), coating, or the like, or mixing a conductive agent with a solvent or a synthetic resin binder. The method of apply | coating is used. Note that the electrode thickness is not particularly limited as long as the conductivity can be secured and the light transmittance is not hindered, and is preferably 3 to 1000 nm, preferably 5 to 400 nm. The material and thickness of the electrode 5 provided on the back substrate 1 side are the same as those of the electrode 6 described above, but need not be transparent. In this case, the external voltage input may be superimposed with direct current or alternating current.

  It is important that the partition wall 4 is provided on a transparent substrate on the observer side, and that only the vicinity of the top portion of the partition wall in the longitudinal sectional shape is a tent tension shape, a triangle shape, a semicircular shape, or a semi-elliptical shape. Preferably, the shape is appropriately set appropriately depending on the type of the image display medium involved in the display, and is not limited in general, but the partition wall width is 2 to 100 μm, preferably 3 to 50 μm, and the partition wall height is 10 to 500 μm, Preferably, it is adjusted to 10 to 200 μm. In forming the partition walls, a single rib method in which ribs are formed only on one side of the substrate (preferably on a transparent substrate but may be on a back substrate) is preferably used in the present invention.

  As shown in FIG. 8, the display cells formed by the partition walls made of these ribs are exemplified by a square shape, a triangular shape, a line shape, a circular shape, and a hexagonal shape when viewed from the substrate plane direction. The shape and the mesh shape are exemplified. It is better to make the portion corresponding to the cross section of the partition wall visible from the display side (the area of the frame portion of the display cell) as small as possible, and the sharpness of the image display increases. Here, examples of the method for forming the partition include a mold transfer method, a screen printing method, a sand blast method, a photolithography method, and an additive method. Among these, a photolithography method using a resist film and a mold transfer method are preferably used.

Next, the powder fluid used as the image display medium in the image display panel which is the subject of the present invention will be described.
The “powder fluid” in the present invention is a substance in an intermediate state of both fluid and particle characteristics that exhibits fluidity by itself without borrowing the force of gas or liquid. For example, liquid crystal is defined as an intermediate phase between a liquid and a solid, and has fluidity that is a characteristic of liquid and anisotropy (optical properties) that is a characteristic of solid (Heibonsha: Encyclopedia) . On the other hand, the definition of particle is an object with a finite mass even if it is negligible, and is said to be affected by gravity (Maruzen: Physics Encyclopedia). Here, even in the case of particles, there are special states of gas-solid fluidized bed and liquid-solid fluids. When gas is flowed from the bottom plate to the particles, upward force is applied to the particles according to the velocity of the gas. Is a gas-solid fluidized bed that is in a state where it can easily flow when it balances with gravity, and it is also called a liquid-solid fluidized state that is fluidized by a fluid (ordinary) Company: Encyclopedia). As described above, the gas-solid fluidized bed body and the liquid-solid fluid are in a state of using a gas or liquid flow. In the present invention, it has been found that a substance in a state of fluidity can be produced specifically without borrowing the force of such gas and liquid, and this is defined as powder fluid.

  That is, the pulverulent fluid in the present invention is in an intermediate state having both the characteristics of particles and liquid, as in the definition of liquid crystal (liquid and solid intermediate phase), and is the characteristic of the above-mentioned particles. It is a substance that is extremely unaffected and exhibits a unique state with high fluidity. Such a substance can be obtained in an aerosol state, that is, a dispersion system in which a solid or liquid substance is stably suspended as a dispersoid in a gas, and the solid substance is used as a dispersoid in the image display device of the present invention. Is.

An image display panel which is an object of the present invention encloses a powder fluid exhibiting high fluidity in an aerosol state in which solid particles are stably suspended as a dispersoid, for example, between gases, at least one of which is transparent. Such a powder fluid can be easily and stably moved by a Coulomb force or the like by applying a low voltage.
As described above, the pulverized fluid used in the present invention is a substance in the intermediate state of both fluid and particle characteristics that exhibits fluidity by itself without borrowing the force of gas or liquid. This powder fluid can be in an aerosol state in particular, and in the image display device of the present invention, a solid substance is used in a state of relatively stably floating as a dispersoid in the gas.

Next, the particles used as the image display medium in the image display panel that is the subject of the present invention will be described.
The particles can contain a charge control agent, a colorant, an inorganic additive, and the like, if necessary, in the resin as the main component, as in the conventional case. Examples of resins, charge control agents, colorants, and other additives will be given below.

  Examples of the resin include urethane resin, urea resin, acrylic resin, polyester resin, acrylic urethane resin, acrylic urethane silicone resin, acrylic urethane fluororesin, acrylic fluororesin, silicone resin, acrylic silicone resin, epoxy resin, polystyrene resin, styrene Acrylic resin, polyolefin resin, butyral resin, vinylidene chloride resin, melamine resin, phenol resin, fluororesin, polycarbonate resin, polysulfone resin, polyether resin, polyamide resin and the like can be mentioned, and two or more kinds can be mixed. In particular, acrylic urethane resin, acrylic silicone resin, acrylic fluororesin, acrylic urethane silicone resin, acrylic urethane fluororesin, fluororesin, and silicone resin are suitable from the viewpoint of controlling the adhesive force with the substrate.

  The charge control agent is not particularly limited. Examples of the negative charge control agent include salicylic acid metal complexes, metal-containing azo dyes, metal-containing oil-soluble dyes (including metal ions and metal atoms), and quaternary ammonium salt systems. Examples thereof include compounds, calixarene compounds, boron-containing compounds (benzyl acid boron complexes), and nitroimidazole derivatives. Examples of the positive charge control agent include nigrosine dyes, triphenylmethane compounds, quaternary ammonium salt compounds, polyamine resins, imidazole derivatives, and the like. In addition, metal oxides such as ultrafine silica, ultrafine titanium oxide, ultrafine alumina, nitrogen-containing cyclic compounds such as pyridine and derivatives and salts thereof, various organic pigments, resins containing fluorine, chlorine, nitrogen, etc. are also charged. It can also be used as a control agent.

  As the colorant, various organic or inorganic pigments and dyes as exemplified below can be used.

Examples of the black colorant include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon and the like.
Examples of blue colorants include C.I. I. Pigment blue 15: 3, C.I. I. Pigment Blue 15, Bituminous Blue, Cobalt Blue, Alkaline Blue Lake, Victoria Blue Lake, Phthalocyanine Blue, Metal-free Phthalocyanine Blue, Phthalocyanine Blue Partial Chlorides, Fast Sky Blue, Indanthrene Blue BC and the like.
Examples of red colorants include bengara, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, risor red, pyrazolone red, watching red, calcium salt, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, Alizarin Lake, Brilliant Carmine 3B, C.I. I. Pigment Red 2 etc.

Yellow colorants include chrome yellow, zinc yellow, cadmium yellow, yellow iron oxide, mineral first yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa Yellow G, Hansa Yellow 10G, Benzidine Yellow G, Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake, C.I. I. Pigment Yellow 12 etc.
Examples of green colorants include chrome green, chromium oxide, pigment green B, C.I. I. Pigment Green 7, Malachite Green Lake, Final Yellow Green G, etc.
Examples of the orange colorant include red chrome yellow, molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, indanthrene brilliant orange RK, benzidine orange G, indanthrene brilliant orange GK, C.I. I. Pigment Orange 31 etc.
Examples of purple colorants include manganese purple, first violet B, and methyl violet lake.
Examples of white colorants include zinc white, titanium oxide, antimony white, and zinc sulfide.

  Examples of extender pigments include barite powder, barium carbonate, clay, silica, white carbon, talc, and alumina white. Examples of various dyes such as basic, acidic, disperse, and direct dyes include nigrosine, methylene blue, rose bengal, quinoline yellow, and ultramarine blue.

Examples of inorganic additives include titanium oxide, zinc white, zinc sulfide, antimony oxide, calcium carbonate, lead white, talc, silica, calcium silicate, alumina white, cadmium yellow, cadmium red, cadmium orange, titanium yellow, Examples include bitumen, ultramarine blue, cobalt blue, cobalt green, cobalt violet, iron oxide, carbon black, manganese ferrite black, cobalt ferrite black, copper powder, and aluminum powder.
These pigments and inorganic additives can be used alone or in combination. Of these, carbon black is particularly preferable as the black pigment, and titanium oxide is preferable as the white pigment.

  The particles used in the present invention preferably have an average particle diameter d (0.5) in the range of 0.1 to 20 μm and are uniform and uniform. If the average particle diameter d (0.5) is larger than this range, the display is not clear, and if it is smaller than this range, the cohesive force between the particles becomes too large, which hinders the movement of the particles.

Furthermore, in the present invention, regarding the particle size distribution of each particle, the particle size distribution Span represented by the following formula is set to less than 5, preferably less than 3.
Span = (d (0.9) −d (0.1)) / d (0.5)
(However, d (0.5) is a numerical value expressed in μm that the particle size is 50% larger than this and 50% smaller than this, and d (0.1) is a particle whose proportion of particles below this is 10%. (Numerical value expressed in μm, d (0.9) is a numerical value expressed in μm for a particle size of 90% or less)
By keeping Span within a range of 5 or less, the size of each particle is uniform and uniform particle movement is possible.

  Furthermore, regarding the correlation between the particles, the ratio of d (0.5) of the particles having the minimum diameter to d (0.5) of the particles having the maximum diameter among the used particles is set to 50 or less, preferably 10 or less. It is essential. Even if the particle size distribution Span is reduced, particles with different charging characteristics move in opposite directions, so that the particle size is close to each other and each particle can be easily moved in the opposite direction by the equivalent amount. This is within this range.

The particle size distribution and the particle size can be obtained from a laser diffraction / scattering method or the like. When laser light is irradiated onto particles to be measured, a light intensity distribution pattern of diffracted / scattered light is spatially generated, and this light intensity pattern has a corresponding relationship with the particle diameter, so that the particle diameter and particle diameter distribution can be measured. .
Here, the particle size and particle size distribution in the present invention are obtained from a volume-based distribution. Specifically, using a Mastersizer2000 (Malvern Instruments Ltd.) measuring machine, particles are introduced into a nitrogen stream and the attached analysis software (software based on volume-based distribution using Mie theory) The diameter and particle size distribution can be measured.

Further, in the present invention, when a particle group or powder fluid is used as the image display medium, it is important to manage the gas in the voids surrounding the particle group or powder fluid between the substrates, which contributes to improved display stability. Specifically, it is important that the relative humidity at 25 ° C. is 60% RH or less, preferably 50% RH or less, more preferably 35% RH or less with respect to the humidity of the gas in the gap.
1 to 3, the gaps between the opposing substrate 1 and substrate 2 in FIGS. 1 to 3, the occupied portions of the electrodes 5 and 6, the particle group (or powder fluid) 3, the occupied portion of the partition 4, and the device A gas portion that is in contact with a so-called particle group (or powder fluid) excluding the seal portion is meant.
The gas in the gap is not limited as long as it is in the humidity region described above, but dry air, dry nitrogen, dry argon, dry helium, dry carbon dioxide, dry methane, and the like are preferable. This gas needs to be sealed in the apparatus so that the humidity is maintained. For example, filling of particles or powder fluid, assembly of the substrate, etc. are performed in a predetermined humidity environment, It is important to apply a sealing material and a sealing method to prevent moisture intrusion.

The distance between the substrates in the image display panel that is the subject of the present invention is only required to be able to move the image display medium and maintain the contrast, but is usually adjusted to 10 to 500 μm, preferably 10 to 200 μm.
The volume occupancy of the particle group or powder fluid in the space between the opposing substrates is preferably 5 to 70%, more preferably 5 to 60%. If it exceeds 70%, the movement of particles or powder fluid is hindered, and if it is less than 5%, the contrast tends to be unclear.
The particle group and powder fluid used in the gas have been described as the image display medium used in the present invention, but the present invention is also applicable to the case of filling an image display medium such as a microcapsule type in which the electrophoretic particle group is encapsulated. it can.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples of the present invention, but the present invention is not limited to the following examples. In addition, the image display panels of Examples and Comparative Examples of the present invention were evaluated by the following methods according to the following criteria.

[Production of image display panel]
First, a transparent glass substrate with electrodes (7 cm × 7 cm □) was prepared, ribs were formed on the substrate, and partition walls were formed.
Ribs were formed as follows. A dry film photoresist NIT250 manufactured by Nichigo Morton, which is a photosensitive film, is laminated on a glass with ITO, exposed to light and developed to have a desired shape in which only the tip is tapered, and the taper at the tip is removed. A partition wall having a thickness of 50 μm, a line of 30 μm, a space of 320 μm, and a pitch of 350 μm was formed. Next, a substrate with an ITO electrode (7 cm × 7 cm □, thickness: 100 μm) is prepared as a back side substrate, and a recess corresponding to the shape of the partition wall of the counterpart substrate is wet-blasted at a portion where the ITO electrode is not formed. Formed by. As this back side substrate, the thing which adjusted the recessed part depth using the non-transparent board | substrate (glass epoxy) was prepared. The back substrate was provided with gap spacers (height: 50 μm) at the four corners of the substrate in order to ensure the distance between the substrates.

Next, two types of particle groups (particle group A and particle group B) having different colors and charging characteristics were prepared.
Next, the substrate on which the partition walls are formed is transferred into a dry container having a humidity of 40% RH or less. First, the particle group A is dispersed as a first particle group into the container from a nozzle provided in the upper part of the container. Then, the particles A were filled by spraying into the cells on the substrate placed at the bottom of the container.
Subsequently, the particle group B is dispersed as a second particle group in a container from another nozzle provided in the upper part of the container, and the inside of the cell on the substrate placed in the lower part of the container (already filled with the particle group A). The particle group A was overlaid and filled by spraying.
The packing arrangement amount of the particle group A and the particle group B was set to the same volume amount, and the volume occupation ratio of both particle groups with respect to the space between the substrates formed by bonding the two substrates was adjusted to 25 vol%.

  Next, another substrate with concave portions is superimposed on the substrate in which the particle group is filled and arranged in the cell, and the periphery of the substrate and the gap spacer are bonded with an epoxy adhesive, and the particle group is sealed for image display. A panel was produced.

[Evaluation of display function]
By applying a voltage of 250 V to the image display device incorporating the prepared image display panel and repeatedly inverting the potential, a black to white solid image is repeatedly displayed, and the quality of the displayed solid image is visually observed. By observing, the stability of image display was evaluated.

[Image display medium]
In Examples and Comparative Examples, black and white two-color particle groups (particle group A and particle group B) having different charging characteristics were used as the image display medium.
The particle group A consists of acrylic urethane resin EAU53B (manufactured by Asia Kogyo Co., Ltd.) / IPDI crosslinking agent Excel Hardener HX (manufactured by Asia Kogyo Co., Ltd.), 4 parts by weight of carbon black (MA100 Mitsubishi Chemical Corporation), charge control. 2 parts by weight of the agent Bontron N07 (Orient Chemical Co., Ltd.) was added, kneaded, pulverized with a jet mill, and mechanical impact force was applied using a hybridizer device (Nara Machinery Co., Ltd.). In addition, classification was made after making it approximately spherical. The produced particle group A was an approximately spherical and negatively charged black particle group having an average particle diameter of 9.1 μm.
Particle group B was prepared by dissolving 0.5 parts by weight of AIBN (azobisisobutyronitrile) in 80 parts by weight of tertiary butyl methacrylate monomer and 20 parts by weight of 2- (diethylamino) ethyl methacrylate. A solution obtained by dispersing 20 parts by weight of titanium oxide, which has been made lipophilic by treatment with an agent, is suspended and polymerized in a 10-fold amount of a 0.5% aqueous surfactant (sodium lauryl sulfate) solution, filtered and dried. Then, it was prepared using a classifier (MDS-2: Nippon Numatic Industries). The produced particle group B was a positively charged spherical white particle having an average particle diameter of 8.5 μm.

<Example 1>
A transparent front substrate on which a partition wall having a vertical cross-sectional shape of a tent-like shape and a height of 20 μm is formed at the tip so that the cells are arranged in a lattice shape with a square shape, and a partition shape with a depth of 25 μm. A display panel was produced in the above-described procedure using a back substrate having a corresponding concave portion formed, and the display function was evaluated. The evaluation results are as shown in Table 1.

<Example 2>
A display panel was prepared in the same manner as in Example 1 except that a transparent front substrate having a partition wall with a triangular section at the tip and a height of 20 μm was used. The function was evaluated. The evaluation results are as shown in Table 1.

<Example 3>
Other than using a transparent front substrate on which a partition wall with a height of 10 μm is formed at the tip of which the vertical cross-sectional shape is a triangle, the particle group is dispersed and filled while applying vibration to the substrate. In the same manner as in Example 2, a display panel was produced according to the procedure described above, and the display function was evaluated. The evaluation results are as shown in Table 1.

<Comparative Example 1>
A display panel was produced in the same manner as in Example 2 except that the depth of the concave portion provided on the back substrate was 10 μm, and the display function was evaluated. The evaluation results are as shown in Table 1.

<Comparative example 2>
The display panel is the same as in each example except for the procedure using a transparent front substrate having a partition wall with a tapered longitudinal sectional shape and a rear substrate without a recess. Was fabricated according to the procedure described above, and the display function was evaluated. The evaluation results are as shown in Table 1.

<Comparative Example 3>
A display panel was prepared and the display function was evaluated in the same manner as in Example 3 except that the shape of the tip of the partition wall was rectangular (top flat, i.e., not tapered). The comparison results are shown in Table 1.

  As described above, according to the present invention, it was found that only the tip of the partition wall is tapered, so that the gradient of the partition wall exposed in the cell is eliminated and stable image display can be performed. Depending on the height of the tapered portion of the tip of the partition wall, the effect of preventing adhesion of the image display medium may be insufficient, but even in such a case, when filling the image display medium adhesion, It has been found that this problem can also be solved by using a method of filling the substrate while applying vibration.

  The image display panel provided in the image display device of the present invention includes display units of mobile devices such as notebook computers, PDAs, mobile phones, and handy terminals, electronic papers such as electronic books and electronic newspapers, bulletin boards such as signboards, posters, and blackboards. It is suitably used for display units such as calculators, home electric appliances, automobile supplies, card display units such as point cards and IC cards, electronic advertisements, electronic POPs, electronic price tags, electronic musical scores, and display units for RF-ID devices.

It is a figure which shows an example of the image display board used for the image display apparatus of this invention. It is a figure which shows the other example of the image display board used for the image display apparatus of this invention. It is a figure which shows the further another example of the image display board used for the image display apparatus of this invention. (A)-(d) is a figure for demonstrating the manufacturing method of the image display panel of this invention. (A)-(c) is a figure for demonstrating the manufacturing method of the image display panel of this invention. (A)-(c) is a figure for demonstrating the modification of the manufacturing method of the image display panel of this invention. (A)-(c) is a figure for demonstrating the modification of the manufacturing method of the image display panel of this invention. It is a figure which shows an example of the shape of the partition in the image display board of the image display apparatus of this invention.

Explanation of symbols

1, 2 Substrate 3 Image display medium (particle, powder fluid)
3W White particles, white powder fluid 3B Black particles, black powder fluid 4 Bulkhead 5 Electrode 6 Electrode 11 Spray nozzle 12 Recess 13 Gap spacer

Claims (10)

Image display is performed by forming a plurality of cells partitioned by a partition wall between two opposing substrates, at least one of which is transparent, enclosing an image display medium in the cells, and applying an electric field to the image display medium. An image display panel that displays an image by moving a medium,
As a partition provided to define the cell for enclosing the image display medium, a partition having a tapered shape only at the tip is provided on a transparent substrate, and the tapered portion of the tip of the partition is fitted to the other substrate. An image display panel, wherein a recess is provided, and the two substrates are overlapped so that the partition wall and the recess are fitted.   2. The image display according to claim 1, wherein the tapered shape of the tip of the partition wall is a tent tension shape, a triangular shape, a semicircular shape, or a semielliptical shape in a longitudinal cross-sectional shape. panel.   The relationship between the height H1 of the tapered portion at the tip of the partition wall in the length direction and the depth H2 of the recess provided in the counterpart substrate is such that H1 ≦ H2. Item 3. The image display panel according to Item 1 or 2.   The image display panel according to claim 1, wherein the image display medium is a particle group or a powder fluid. Image display is performed by forming a plurality of cells partitioned by a partition wall between two opposing substrates, at least one of which is transparent, enclosing an image display medium in the cells, and applying an electric field to the image display medium. An image display panel manufacturing method for displaying an image by moving a medium,
As a partition provided to define the cell for enclosing the image display medium, a partition having a tapered shape only at the tip is provided on a transparent substrate, and the tapered portion at the tip of the partition is fitted to the other substrate. Producing a panel for image display, characterized in that a recess is provided and the substrate on which the partition wall is provided is filled with an image display medium, and then the two substrates are overlapped so that the partition wall and the recess are fitted. Method.   6. The image display panel according to claim 5, wherein the tapered shape of the tip of the partition wall is provided in any one of a tent tension shape, a triangle shape, a semi-circular shape, and a semi-elliptical shape in a longitudinal sectional shape. Manufacturing method.   The relationship between the height H1 of the tapered portion at the tip of the partition wall in the length direction and the depth H2 of the recess provided in the counterpart substrate is such that H1 ≦ H2. Item 7. A method for producing an image display panel according to Item 5 or 6.   The method for manufacturing an image display panel according to claim 5, wherein the image display medium is a particle group or a powder fluid.   An image display device comprising the image display panel according to claim 1.   An image display device comprising the image display panel manufactured by the method for manufacturing an image display panel according to claim 5.

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