JP2006058564A - Manufacturing method of image display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the manufacturing method of an image display panel which can obtain a superior panel without leaving an image display medium between the tops of the barrier ribs and the substrate. <P>SOLUTION: The manufacturing method of an image display panel forms cells 15 by dividing one another with barrier ribs 4 between the two substrates 1, 2 facing each other and at least one of which is transparent, then fills at least two kinds of image display mediums 3 different in color and electro static charging property in those cells to display images by applying electric fields to the image display mediums. The method puts the liquid 13 made by dispersing at least two kinds of image display mediums 3 in a dispersing medium 12 at the predetermined positions on a substrate 1 (2) through a mask 11, and stacks the other substrate 2 (1) after drying and removing the dispersing medium 12. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention forms a plurality of cells partitioned by partition walls 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 a method for manufacturing an image display panel that displays an image by moving an image display medium.

  2. Description of the Related Art Conventionally, image display devices using techniques such as an electrophoresis method, an electrochromic method, a thermal method, and a two-color particle rotation method have been proposed as image display devices that can replace liquid crystal (LCD).

  Compared to LCDs, 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 mobile terminals, electronic paper, and the like. Particularly recently, an electrophoretic method in which a dispersion liquid composed of dispersed particles and a colored solution is encapsulated and disposed between opposing substrates has been proposed and is expected.

  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, the structure is complicated because the charge transport layer and further the charge generation layer are arranged, and it is difficult to inject the charges into the conductive particles.

As one method for solving the various problems described above, a cell isolated from each other by a partition is formed between two opposing substrates, at least one of which is transparent, and an image display medium is sealed in the cell. 2. Description of the Related Art An image display panel that displays an image by applying an electric field to an image display medium and moving the image display medium is known. In the case of these dry image display medium moving display systems, the image display medium is sealed between the substrates of the image display panel, but the image display medium is prevented from becoming unevenly distributed as the movement is repeated. For this purpose, a method of enclosing an image display medium in a small room (cell) surrounded by a partition wall is used.
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” Proceedings, p.249-252

  FIGS. 11A to 11D are diagrams for explaining problems in the conventional method for manufacturing an image display panel. In the conventional method for manufacturing an image display panel, first, as shown in FIG. 11A, a mask 53 that closes the top of the partition wall 51 is placed on the substrate 52 provided with the partition wall 51, and the partition wall 51 defines it. The image display medium 56 is sprayed from the spray nozzle 55 into the cells 54, and the cells 54 are filled with the image display medium 56. As shown in FIG. 11B, after the spraying of the image display medium 56 is finished, the mask 53 is removed so that the image display medium 56 does not remain on the top of the partition wall 51. However, as shown in FIG. 11C, the image display medium 56 may be placed on the top of the partition wall after the mask 53 is removed. In this state, when the other substrate 57 is overlaid, as shown in FIG. 11D, the image display medium 56 deposited and attached to the top of the partition wall is sandwiched between the partition wall 51 and the substrate 57, and in panel performance. It was a problem.

  With respect to the image display medium 56 that is deposited and adhered to the top of the partition wall in the above-described conventional manufacturing method, it is difficult to install the mask 53 with the top position of the partition wall exactly aligned. One cause is that the image display medium 56 is loaded. Further, even if the mask 53 is positioned exactly on the top of the partition wall, it cannot be brought into close contact with the top of the partition wall, so that the image display medium 56 enters the gap between the mask 53 and the top of the partition wall, resulting in the top of the partition wall. One of the causes is that the image display medium 56 is loaded.

  In order to solve these problems, the present applicant, in Japanese Patent Application No. 2004-21563, in filling a cell with an image display medium, a dispersion liquid in which the image display medium is dispersed in a dispersion medium made of a liquid. The technique of filling is described. However, it has been difficult to completely remove the image display medium on the top of the partition wall even with the technique of filling the cell with the image display medium as a dispersion.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a method for manufacturing an image display panel in which an image display medium hardly remains between the top of a partition wall and a substrate, and good panel performance can be obtained. Is.

  In the method for manufacturing an image display panel according to 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 at least different colors and charging characteristics are formed in the cells. Dispersing at least two types of image display media in a method for manufacturing an image display panel that encloses two types of image display media and moves the image display media to display an image by applying an electric field to the image display media. The dispersion liquid dispersed in a medium is placed at a predetermined position on the substrate through a mask, and after the dispersion medium is removed by drying, the other substrate is overlaid.

  As a preferred example of the method for manufacturing an image display panel according to the present invention, a mask is set on a substrate having a partition wall, an image display medium is filled in the cell through the mask, and then the other substrate is overlaid. A mask is set on a substrate on which a partition wall is not formed, an image display medium is arranged at a predetermined position on the substrate through the mask, and then the other substrate having the partition wall is overlapped, the back side of the mask Apply a dispersion medium to the substrate, and set the mask in place before the dispersion medium dries. The dispersion medium may be ethanol, methanol, propanol, isopropanol, butanol and other alcohols, water, acetone, and their It may be a mixture and the image display medium may be a particle group or a powder fluid.

  In the present invention, a dispersion liquid in which at least two types of image display media are dispersed in a dispersion medium is disposed at a predetermined position on the substrate through a mask, and after the dispersion medium is removed by drying, the other substrate is superimposed. Thus, it is difficult to leave an image display medium between the top of the partition wall and the substrate, and it is possible to achieve a method for manufacturing an image display panel capable of obtaining good panel performance.

  First, the basic configuration of the image display panel of the present invention will be described. In the image display panel of the present invention, an electric field is applied to a chargeable image display medium (particle group or powder fluid) sealed between two opposing substrates. The charged image display medium is attracted by the electric field force or Coulomb force along the applied electric field direction, and the image display medium is reciprocated by the change in electric field direction due to the potential switching, 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, the force applied to the particles or powder fluid used as the image display medium is not only the force attracted by the Coulomb force between the particles or powder fluid, but also the image power, intermolecular force, liquid crosslinking force with the electrode or substrate. , Gravity and so on.

An example of the image display panel of the present invention will be described with reference to FIGS.
In the example shown in FIG. 1, an image display medium 3 having different colors composed of at least one kind of particles (here, white particles 3W and black particles 3B are shown) is applied to an electric field applied from the outside of the substrates 1 and 2. Accordingly, the black particles 3B are moved perpendicularly to the substrates 1 and 2 so that the observer can visually recognize the black particles 3B, or the white particles 3W are visually recognized by the observer. A partition cell 4 is provided between the substrates 1 and 2 in a lattice shape, for example, to define a display cell.
In the example shown in FIG. 2, an image display medium 3 (here, white particles 3 </ b> W and black particles 3 </ b> B) having different colors composed of at least one kind of particles is provided on the electrode 5 and the substrate 2 provided on the substrate 1. Depending on the electric field generated by applying a voltage between the electrodes 6 provided, the substrate 6 is moved perpendicularly to the substrates 1 and 2, and the black particles 3B are visually recognized by the observer, or black display is performed, or The white particles 3W are visually recognized by an observer to display white. A partition cell 4 is provided between the substrates 1 and 2 in a lattice shape, for example, to define a display cell.
In the example shown in FIG. 3, an electric field generated by applying a voltage between the electrode 5 and the electrode 6 provided on the substrate 1 is applied to the image display medium 3 of one color (here, the white particles 3 </ b> W). Accordingly, 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. 1 color is displayed. A partition cell 4 is provided between the substrates 1 and 2 in a lattice shape, for example, 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.

  The feature of the method for manufacturing an image display panel according to the present invention is that a dispersion liquid in which at least two types of image display media are dispersed in a dispersion medium is disposed at a predetermined position on a substrate through a mask, and the dispersion medium is removed by drying. After that, by superimposing the other substrate, that is, by disposing the dispersion liquid in which the image display medium is dispersed in the dispersion medium on the substrate through the mask, the image display medium remaining on the top of the partition wall is almost completely obtained. The point is to remove. Hereinafter, a specific method will be described.

  4A to 4F are views showing an example of a method for manufacturing an image display panel according to the present invention in the order of steps. In the example shown in FIGS. 4A to 4F, the mask 11 is set on the substrate 2 having the partition walls 4 serving as the back substrate, and the image display medium 3 is filled through the mask 11, and then the other substrate is provided. A substrate 1 serving as a transparent front substrate is overlaid.

  First, as shown in FIG. 4A, a dispersion 13 is prepared in which at least two types of image display media 3 (here, two types of white particle groups 3W and black particle groups 3B) are dispersed in a dispersion medium 12. . Here, the particle group or the powder fluid used as the image display medium 3 has chargeability in a dry state, and the liquid used as the dispersion medium 12 is preferably one that does not impair the chargeability during drying of the image display medium 3. . Specifically, as the dispersion medium 12 made of a liquid, alcohols such as ethanol, methanol, propanol, isopropanol, and butanol, water, acetone, and a mixture thereof are used. From the viewpoint of good dry-removability after filling in the cell and environmental hygiene, ethanol and an ethanol / water mixture are preferably used.

  At the same time, a mask 11 is set on the substrate 2 having the partition walls 4 as shown in FIG. Note that if the opening shape and area of the mask 11 are made smaller than the cell shape and area, even if the mask 11 cannot be placed with a slight shift in position, the mask 11 can be dispersed evenly. It is preferable that the liquid 13 does not enter. Further, in order to closely align the mask 11 with a predetermined position, a thin dispersion medium 12 (for example, ethanol) is applied to the back side of the mask 11 and set at a predetermined position before the dispersion medium 12 is dried. An undried dispersion medium film 14 is preferably formed between 4 and the mask 11. As a result, the adhesion between the partition walls 4 and the mask 11 is maintained by the undried dispersion medium film 14 provided between the partition walls 4 and the mask 11, and the image display medium 3 in the dispersion 13 poured later is separated from the partition walls 4. And the mask 11 will not enter.

  Next, as shown in FIG. 4B, the dispersion liquid 13 is filled into the cell 15 defined by the partition wall 4 through the mask 11. Here, as an example, the dispersion 13 is filled at a predetermined position on the substrate 2 through the mask 11 by filling the dispersion 13 with a blade 16 so as to be pushed into the opening of the mask 11. And when it will be in the state as shown in FIG.4 (c), filling of the dispersion liquid 13 is complete | finished. Next, in the state shown in FIG. 4C, the mask 11 is set and dried, or the mask 11 is removed and dried, and the dispersion medium 12 in the dispersion liquid 13 is removed. As shown in FIG. 4D, only the image display medium 3 is filled in the cell 15. Finally, as shown in FIG. 4E, the other transparent front substrate 1 is superposed from above, so that the image display panel of the present invention is obtained as shown in FIG. Obtainable.

  5A to 5G are views showing another example of the image display panel manufacturing method of the present invention in the order of steps. In the example shown in FIGS. 5A to 5G, the substrate 1 on which the partition walls 4 are not formed is used as the substrate for filling the image display medium 3, and the substrate 1 on which the partition walls 4 are not formed is used. On the other hand, the mask 11 is set, and the image display medium 3 is arranged at a predetermined position on the substrate 1 through the mask 11, and then the other substrate 2 having the partition walls 4 is overlaid.

  First, as shown in FIG. 5A, a dispersion 13 is prepared in which at least two types of image display media 3 (here, two types of white particle groups 3W and black particle groups 3B) are dispersed in a dispersion medium 12. . The dispersion medium 12 is the same as that described above. At the same time, as shown in FIG. 5A, a mask 11 is set on the substrate 1 on which the partition walls 4 are not formed. Also in this case, by making the shape and area of the opening of the mask 11 smaller than the cell shape and area, even if the mask 11 cannot be placed in perfect alignment, the portion covered with the mask 11 (the other one will be described later) It is preferable that the image display medium 3 is not placed on a portion (part joined to the partition wall 4 formed on the substrate 2 side). In this example, the mask 11 is made of a material that can be attracted by a magnet from a magnetic material, such as an iron-based metal material, and a magnetic material (not shown) is disposed on the back side of the substrate 1 when the mask 11 is placed on the substrate 1. However, it is also possible to adopt a configuration that attracts the mask 11. The configuration of the mask 11 is not essential in the present invention, but such a configuration is preferable because the adhesion between the mask 11 and the substrate 1 can be improved.

  Next, as shown in FIG. 5B, the dispersion 13 is filled into the opening of the mask 11 through the mask 11. Here, as an example, the dispersion 13 is filled at a predetermined position on the substrate 1 through the mask 11 by filling the dispersion 13 so as to be pushed into the opening of the mask 11 with the blade 16. And when it will be in the state as shown in FIG.5 (c), filling of the dispersion liquid 13 is complete | finished. Next, in the state shown in FIG. 5C, drying is performed with the mask 11 set, and the dispersion medium 12 in the dispersion 13 is removed. In this example, if the mask 11 is removed before the dispersion medium 12 is dried and removed, the dispersion liquid 13 protrudes from the predetermined position and spreads. Therefore, it is necessary to dry the mask 11 while it is kept. Next, after drying and removing the dispersion medium as shown in FIG. 5 (d), the mask 11 is removed, and the state shown in FIG. 5 (e) is obtained. Finally, as shown in FIG. 5 (f), the other substrate 2 having the partition walls 4 is overlaid from above, thereby obtaining the image display panel of the present invention as shown in FIG. 5 (g). Can do.

  6 (a), 6 (b) to 9 (a), 9 (b) are diagrams showing an example of a mask used in the method for manufacturing an image display panel of the present invention and a partition wall when the mask is used. . 6A shows a mask 11 having a hexagonal opening and a honeycomb arrangement, and FIG. 6B shows a partition wall 4 having a hexagonal opening and a honeycomb arrangement used when the mask 11 of FIG. 6A is used. Is shown. FIG. 7A shows a mask 11 having a circular opening and a honeycomb arrangement, and FIG. 7B shows a partition 4 having a hexagonal cell and a honeycomb arrangement used when the mask 11 of FIG. 7A is used. Show. 8A shows a mask 11 having a square opening and a grid arrangement, and FIG. 8B shows a partition 4 having a square opening and a grid arrangement used when the mask 11 of FIG. 8A is used. Is shown. FIG. 9A shows a mask 11 having a circular opening and a honeycomb arrangement, and FIG. 9B shows partition walls 4 having a square cell and a honeycomb arrangement when the mask 11 of FIG. 9A is used. ing.

  In the example described above, the display cells formed by the barrier ribs 4 are exemplified by a square shape, a triangular shape, a line shape, a circular shape, and a hexagonal shape as viewed from the substrate plane direction as shown in FIG. A honeycomb shape or a mesh shape is 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. Examples of the method for forming the partition walls 4 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. In any method, the present invention can be suitably used.

  Hereafter, each member which comprises the image display panel of this invention is demonstrated.

  As for the substrate, at least one substrate is the transparent substrate 1 from which the color of the image display medium can be confirmed from the outside of the panel, and a material having high visible light transmittance and good heat resistance is preferable. The substrate 2 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 2 to 5000 μm, more preferably 5 to 2000 μm. If it is too thin, it will be difficult to maintain the strength and the uniformity of the distance between the substrates, and if it is thicker than 5000 μm, it will be a thin image display panel. Is inconvenient.

  Electrode forming materials for electrodes provided as necessary include metals such as aluminum, silver, nickel, copper, and gold, conductive metal oxides such as ITO, indium oxide, conductive tin oxide, and conductive zinc oxide, polyaniline , Conductive polymers such as polypyrrole and polythiophene are exemplified, and 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. The electrode provided on the viewing side substrate needs to be transparent, but the electrode provided on the back side substrate does not need to be transparent. In any case, the above-mentioned material that is conductive and capable of pattern formation can be suitably 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 provided on the back side substrate are the same as those of the electrode provided on the viewing side substrate described above, but need not be transparent. In this case, the external voltage input may be superimposed with direct current or alternating current. The distance between the substrates in the image display panel of the present invention is not limited as long as the image display medium can be moved and the contrast can be maintained, but is usually adjusted to 10 to 500 μm, preferably 10 to 200 μm.

  Next, the powder fluid as an image display medium used in the image display panel of the present invention will be described. As for the name of the powder fluid as the image display medium of the present invention, the present applicant has obtained the right of “Electronic Powder Fluid (registered trademark)”.

  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.

The image display panel of the present invention is a powder fluid exhibiting high fluidity in an aerosol state in which solid particles are stably suspended as a dispersoid, for example, as an image display medium between two opposing substrates, at least one of which is transparent. Such a powder fluid can be easily and stably moved by a Coulomb force by applying a low voltage.
As described above, for example, the powder fluid used in the present invention is a substance in an intermediate state between fluid and particles, which 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 as the image display medium used in the image display panel 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, resol 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 yellow lead, 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, 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.

  Moreover, it is preferable that the particles used as the image display medium used in the image display panel of the present invention 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 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 expressing the particle diameter in μm that 50% of the particles are larger than this and 50% is smaller than this, and d (0.1) is a particle in which the ratio of the smaller particles is 10%. (Numerical value expressed in μm, and d (0.9) is a numerical value expressed in μm for a particle diameter 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 becomes 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.

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 instrument, put particles into a nitrogen stream and use the attached analysis software (software based on volume-based distribution using Mie theory). The diameter and particle size distribution can be measured.

  The charge amount of the particles constituting the image display medium naturally depends on the measurement conditions, but the charge amount of the particles constituting the image display medium in the image display panel is almost equal to the initial charge amount, contact with the partition walls, and the substrate. It was found that the saturation value of the charging behavior of the particles constituting the image display medium is a dominant factor, depending on the charge decay with contact and elapsed time.

Furthermore, in the present invention, when a particle group or powder fluid is used for the image display medium, it is important to manage the gas in the void surrounding the image display medium 3 (particle group or powder fluid) between the substrates, and display stability is improved. Contribute to. 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.
In FIG. 1 to FIG. 3, this void portion is an area occupied by the electrodes 5 and 6, the image display medium (particle group or powder fluid 3), and an area occupied by the partition wall 4 from the portion sandwiched between the opposing substrates 1 and 2. A gas portion in contact with a so-called image display medium excluding a portion (a portion where a partition wall defining a cell exists) and a panel seal portion is used.
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 panel so that the humidity is maintained. For example, the image display medium is filled and the panel is assembled in a predetermined humidity environment. It is important to apply a sealing material and a sealing method to prevent the above.

  The volume occupancy of the image display medium (particle group or powder fluid) in the space between the opposing substrates is preferably 5 to 70%, more preferably 5 to 60%. When it exceeds 70%, the movement of the image display medium (particle group or powder fluid) is hindered, and when it is less than 5%, the contrast tends to be unclear.

  An image display panel obtained by the manufacturing method of the present invention is a display unit of a mobile device such as a notebook computer, a PDA, a mobile phone, and a handy terminal, an electronic paper such as an electronic book and an electronic newspaper, a bulletin board such as a signboard, a poster, and a blackboard. 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 panel of this invention. It is a figure which shows the other example of the image display panel of this invention. It is a figure which shows the further another example of the image display panel of this invention. (A)-(f) is a figure which shows an example of the manufacturing method of the image display panel of this invention in order of a process, respectively. (A)-(g) is a figure which shows the other example of the manufacturing method of the image display panel of this invention in order of a process. (A), (b) is a figure which shows an example of the partition used when using the mask used with the manufacturing method of the image display panel of this invention, respectively. (A), (b) is a figure which shows the other example of the partition used when using the mask used with the manufacturing method of the image display panel of this invention, and the mask, respectively. (A), (b) is a figure which shows the further another example of the partition used when using the mask used with the manufacturing method of the image display panel of this invention, and the mask, respectively. (A), (b) is a figure which shows the further another example of the partition used when using the mask used with the manufacturing method of the image display panel of this invention, and the mask, respectively. It is a figure which shows an example of the shape of the partition in the image display panel of this invention. (A)-(d) is a figure for demonstrating the problem in the manufacturing method of the conventional image display panel, respectively.

Explanation of symbols

1, 2 Substrate 3 Image display medium (particle group or powder fluid)
3W white particles (white powder fluid)
3B Black particles (black powder fluid)
4 Partition 5 and 6 Electrode 11 Mask 12 Dispersion medium 13 Dispersion 14 Undried dispersion medium film 15 Cell 16 Blade

Claims (6)

  A plurality of cells partitioned by a partition wall are formed between two opposing substrates, at least one of which is transparent, and at least two types of image display media having different colors and charging characteristics are sealed in the cells to display an image. In a method for manufacturing an image display panel that displays an image by moving an image display medium by applying an electric field to the medium, a dispersion liquid in which at least two types of image display media are dispersed in a dispersion medium is passed through a mask. A method for manufacturing an image display panel, comprising: arranging at a predetermined position on a substrate, drying and removing the dispersion medium, and superimposing the other substrate.   2. The image display panel according to claim 1, wherein a mask is set on a substrate having a partition wall, the image display medium is filled in the cell through the mask, and then the other substrate is overlaid. Production method.   A mask is set on a substrate on which a partition wall is not formed, an image display medium is disposed at a predetermined position on the substrate through the mask, and then another substrate having the partition wall is overlaid. 2. A method for producing an image display panel according to 1.   4. The image display panel according to claim 1, wherein a dispersion medium is applied to the back side of the mask, and the mask is set at a predetermined position before the dispersion medium is dried. Method.   The image display panel according to any one of claims 1 to 4, wherein the dispersion medium is an alcohol such as ethanol, methanol, propanol, isopropanol, or butanol, water, acetone, or a mixture thereof. Manufacturing method.   The method for manufacturing an image display panel according to claim 1, wherein the image display medium is a particle group or a powder fluid.

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