JP2007139979A - Information display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information display panel whose panel display surface is improved lightness by taking measures to improve a rate of convergence of reflected light from a display medium between peaks of partition walls forming pixels and a display-surface side transparent substrate. <P>SOLUTION: The information display panel in which unit cells partitioned by partition walls 4U for unit cell between the display-surface side transparent substrate 2 and a back-surface side substrate 1 are each composed of three pixels and transparent color filters 7R, 7G, and 7B of three primary colors (R, G, and B) are arranged by the pixels on the display-surface side transparent substrate 2 side and which performs color display of information such as an image by moving white and black display media 3W and 3B of two colors charged in air spaces of the pixels is provided with a colored layer (BM)8 between the peaks of the partition walls 4U for unit cells and the display-surface side transparent substrate 2 and no colored layer between peaks of partition wall 4P for pixel and the display-surface side transparent substrate 2. Consequently, the rate of convergence of the reflected light from the display media becomes high, so the lightness is improved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  In the present invention, each of a plurality of unit cells partitioned by a partition between two substrates is composed of three pixels, and a transparent color filter of three primary colors is arranged for each pixel on the transparent substrate side. An information display panel for displaying information such as images by moving a black and white display medium enclosed between air and voids in a pixel so that the enclosed display medium is not unevenly distributed. The present invention relates to an information display panel provided.

  As a conventional example of an information display panel for displaying information such as images in color, as shown in FIG. 9, two-color black and white display media (particle groups or powder fluid) 101W, 101B are used as three primary color transparent color filters 102R, An information display panel (see, for example, Patent Document 1) in which information such as an image is displayed in color by enclosing an air space in a unit cell 105 between substrates 103 and 104 on which 102G and 102B are respectively disposed, and moving a display medium by an electric field. See).

International Publication No. WO2004 / 008239 Pamphlet

  In the conventional information display panel, when white particles and black particles are used as the display medium, the reflected light from the white particles or the reflected light from the black particles is color-combined through the transparent color filters 102R, 102G, and 102B. A color display is performed by providing a colored layer 107 between the top of the partition wall 106 forming the unit cell and the substrate 103, and coloring between the top of the partition wall 108 forming the pixel and the substrate 103. Since the layer 107 is provided, the black density can be increased, but there is a problem that the display state of the panel display surface becomes dark due to absorption by the transparent color filter.

  The present invention is for information display in which the brightness of the panel display surface is improved by taking a measure for improving the concentration of reflected light from the display medium between the top of the partition walls forming the pixels and the transparent substrate on the display surface side. The purpose is to provide a panel.

  In order to achieve the above object, the information display panel according to the present invention comprises three unit cells each of which is partitioned by a partition wall between two substrates, each of which is composed of three pixels. A unit cell is constructed in an information display panel in which transparent color filters of the three primary colors are arranged, and a black and white display medium enclosed between the air and hollow in the pixel is moved to display information such as images in color. A colored layer is provided between the top of the partition wall and the display surface side transparent substrate, and no colored layer is provided between the top of the partition wall forming the pixel and the display surface side transparent substrate.

  Moreover, as a suitable example of the information display panel of the present invention, a predetermined space is provided between the top of the partition wall forming the pixel not provided with the colored layer and the display surface side transparent substrate, and no colored layer is provided. In some cases, a white layer is provided between the top of the partition walls forming the pixels and the display surface side transparent substrate, and the colored layer is a black matrix.

  According to the information display panel of the present invention having the above-described configuration, each of the plurality of unit cells partitioned by the partition between the two substrates is composed of three pixels, and each pixel is provided with three primary colors on the transparent substrate side. A partition that constitutes a unit cell of an information display panel in which a transparent color filter of a certain color is arranged and a black and white display medium enclosed between air and voids in a pixel is moved to display information such as an image in color A colored layer is provided between the top of the LCD and the display surface side transparent substrate, but no colored layer is provided between the top of the partition wall forming the pixels and the display surface side transparent substrate. Brightness is improved because the collection ratio of reflected light from the display medium is increased in accordance with the cross-sectional area of the partition wall forming the pixel without the layer. Therefore, an information display panel in which the brightness of the panel display surface is improved can be provided.

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

  First, a basic configuration of an information display panel that is an object of the present invention will be described. In the information display panel which is an object of the present invention, an electric field is applied to a display medium sealed between two opposing substrates. Along with the applied electric field direction, the charged display medium is attracted by the electric field force or Coulomb force, etc., and the display medium changes the moving direction by the electric field direction change due to the potential switching, thereby displaying information such as an image. Made. Therefore, it is necessary to design the information display panel so that the display medium can move uniformly and maintain stability when rewriting the display repeatedly or when displaying the display information continuously. Here, as the force applied to the particles constituting the display medium, in addition to the force attracting each other by the Coulomb force between the particles, an electric mirror image force between the electrode and the substrate, an intermolecular force, a liquid cross-linking force, gravity and the like can be considered.

  An example of an information display panel that is an object of the present invention will be described with reference to FIGS.

  In the example shown in FIG. 1, at least two or more types of display media 3 (here, white display particles composed of particles 3Wa for white display media) having different optical reflectivity and charging characteristics composed of at least one type of particles. The black display medium 3B, which is composed of a particle group of the medium 3W and the black display medium particles 3Ba, is moved in a direction perpendicular to the substrates 1 and 2 in accordance with the electric field applied from the outside of the substrates 1 and 2. 3B is visually recognized by the observer and black display is performed, or the white display medium 3W is visually recognized by the observer and white display is performed. In the example shown in FIG. 1, for example, a partition 4 is provided in a lattice shape between the substrates 1 and 2 to form a cell. Moreover, in FIG. 1, the partition in front is abbreviate | omitted.

  In the example shown in FIG. 2, at least two or more types of display media 3 (here, white display particles composed of particles 3Wa for white display media) having different optical reflectance and charging characteristics composed of at least one type of particles. The black display medium 3B including a particle group of the medium 3W and the black display medium particles 3Ba) is generated by applying a voltage between the electrode 5 provided on the substrate 1 and the electrode 6 provided on the substrate 2. Depending on the electric field, the substrate is moved perpendicularly to the substrates 1 and 2 and the black display medium 3B is visually recognized by the observer to display black, or the white display medium 3W is visually recognized by the observer and white display is performed. Is going. In the example shown in FIG. 2, for example, a partition 4 is provided between the substrates 1 and 2 in a lattice shape to form a cell. Moreover, in FIG. 2, the partition in front is abbreviate | omitted.

  The above description is similarly applied to the case where the white display medium 3W including the particle group is replaced with the white display medium including the powder fluid and the black display medium 3B including the particle group is replaced with the black display medium including the powder fluid. be able to.

  A configuration example of the information display panel according to the present invention will be described below with reference to FIGS. The information display panel of the present invention has three pixels each of unit cells partitioned by partition walls (hereinafter referred to as “unit cell partition walls”) 4U constituting a unit cell between the display surface side transparent substrate 2 and the back side substrate 1. The three primary colors (R, G, B) of transparent color filters 7R, 7G, 7B are arranged for each pixel on the transparent substrate 2 side of the display surface side, and the two colors of black and white are enclosed between the air and voids in the pixel. Information display panel that displays information such as images in color by moving the display mediums 3W and 3B, and supports color display of information such as images with respect to the information display panels shown in FIGS. Changes (addition of a transparent color filter, etc.) are added, and an “internal electric field drive type (with internal electrodes) information display panel” shown in FIG. 3A and FIG. "External electric field drive type" There are two types of information display panel "of the internal without electrodes).

  The color display compatible information display panel shown in FIG. 3A is provided with transparent color filters 7R, 7G, and 7B on the substrate 2 side which is the display surface side transparent substrate of the information display panel shown in FIG. A black matrix (hereinafter referred to as BM) 8 which is a colored layer is provided between the top of the unit cell partition wall 4U and the substrate 2, and a countermeasure for improving the reflected light collection rate from the display medium described later is taken. . Similarly, in the color display compatible information display panel shown in FIG. 3B, transparent color filters 7R, 7G, and 7B are provided on the substrate 2 side which is the display surface side transparent substrate of the information display panel shown in FIG. In addition, a BM 8 that is a colored layer is provided between the top of the unit cell partition wall 4U and the substrate 2, and a countermeasure for improving the reflected light condensing rate from the display medium described later is taken.

  Hereinafter, measures for improving the light collection rate of reflected light from the display medium will be described with reference to FIGS. 4 to 7 show a case where the countermeasure for improving the light collection rate of reflected light from the display medium is applied to the “information display panel of external electric field drive type (no internal electrode)” of FIG. 3B. However, the present invention can be similarly configured when applied to the “information display panel of internal electric field drive type (with internal electrodes)” of FIG.

  In the example shown in FIG. 4, each of a plurality (two in the illustrated example) of unit cells partitioned by a unit cell partition wall 4U between the display surface side transparent substrate 2 and the back substrate 1 is divided into pixel partition walls 4P. The transparent color filters 7R, 7G, and 7B of the three primary colors (R, G, and B) are arranged for each pixel on the inner surface side of the display surface side transparent substrate 2, respectively. A white display medium 3W and a black display medium 3B are enclosed between the hollows, and a colored layer (BM) 8 is provided between the top of the unit cell partition wall 4U and the display surface side transparent substrate 2, and the top of the pixel partition wall 4P. The pixel partition 4P and the display surface side transparent substrate 2 are directly coupled without providing the colored layer (BM) 8 between the display surface side transparent substrate 2 and the display surface side transparent substrate 2. In the illustrated example, the transparent color filters 7R, 7G, and 7B are provided on the inner surface side of the display surface side transparent substrate 2, but may be provided on the outer surface side of the display surface side transparent substrate 2.

  In the example shown in FIG. 5, each of a plurality (two in the illustrated example) of unit cells partitioned by a unit cell partition wall 4U between the display surface side transparent substrate 2 and the back substrate 1 is divided into pixel partition walls 4P. The transparent color filters 7R, 7G, and 7B of the three primary colors (R, G, and B) are arranged for each pixel on the outer surface side of the transparent substrate 2 on the display surface side. A white display medium 3W and a black display medium 3B are enclosed between the hollows, and a colored layer (BM) 8 is provided between the top of the unit cell partition wall 4U and the display surface side transparent substrate 2, and the top of the pixel partition wall 4P. A space 9 as shown in the figure is formed between the pixel partition 4P and the display surface side transparent substrate 2 without providing the colored layer (BM) 8 between the display surface side transparent substrate 2 and the display surface side transparent substrate 2. In the illustrated example, the transparent color filters 7R, 7G, and 7B are provided on the outer surface side of the display surface side transparent substrate 2, but may be provided on the inner surface side of the display surface side transparent substrate 2.

  In the example shown in FIG. 6, each of a plurality of (two in the illustrated example) unit cells partitioned by a unit cell partition wall 4U between the display surface side transparent substrate 2 and the back side substrate 1 is a pixel partition wall 4P. The transparent color filters 7R, 7G, and 7B of the three primary colors (R, G, and B) are arranged for each pixel on the inner surface side of the display surface side transparent substrate 2, respectively. A white display medium 3W and a black display medium 3B are enclosed between the hollows, and a colored layer (BM) 8 is provided between the top of the unit cell partition wall 4U and the display surface side transparent substrate 2, and the top of the pixel partition wall 4P. A white layer 10 is provided instead of the colored layer (BM) 8 between the transparent substrate 2 and the display surface side transparent substrate 2.

  In the example shown in FIG. 7, each of a plurality of (two in the illustrated example) unit cells partitioned by a unit cell partition wall 4U between the display surface side transparent substrate 2 and the back surface substrate 1 is divided into pixel partition walls 4P. The transparent color filters 7R, 7G, and 7B of the three primary colors (R, G, and B) are arranged for each pixel on the outer surface side of the transparent substrate 2 on the display surface side. A white display medium 3W and a black display medium 3B are enclosed between the hollows, and a colored layer (BM) 8 is provided between the top of the unit cell partition wall 4U and the display surface side transparent substrate 2, and the top of the pixel partition wall 4P. A white layer 10 is provided instead of the colored layer (BM) 8 between the transparent substrate 2 and the display surface side transparent substrate 2. The combination of R, G, and B has been described as the three primary colors so far, but a transparent color filter of the three primary colors of cyan (C), magenta (M), and yellow (Y) may be used.

The unit cell partition wall 4U and the pixel partition wall 4P are units that are completely surrounded by the respective partition walls, even if they are continuous to form unit cells / pixels completely surrounded by the partition walls. It may be intermittent to form cells / pixels, a function to prevent uneven distribution of the display medium (both common), and a function to maintain a gap between substrates at a predetermined size (unit cell partition wall 4U only). As long as it has.
In the relationship between the unit cell partition wall 4U and the pixel partition wall 4P, the unit cell partition wall 4U is provided with the inter-substrate gap maintaining function, and the pixel partition wall 4P is not provided with the inter-substrate gap maintaining function. There may be a gap between the top of 4P and the display surface side transparent substrate 2, and when there is a gap, the reflected light from the particles 3Wa of the white display medium 3W in the adjacent pixel can also be captured. Therefore, it is advantageous in terms of panel brightness.

  According to the information display panel of the present invention, in the unit cell partitioned by the unit cell partition wall 4U between the display surface side transparent substrate 2 and the back surface substrate 1, the top of the unit cell partition wall 4U and the display surface side transparent A colored layer (BM) 8 is provided between the substrate 2 and the colored layer (BM) 8 is not provided between the top of the pixel partition 4P and the display surface side transparent substrate 2 in the example of FIG. In the example of FIG. 5, a space 9 is formed instead of providing the colored layer (BM) 8 between the top of the pixel partition 4P and the display surface side transparent substrate 2, and in the examples of FIGS. 6 and 7, the pixel partition is formed. Since the white layer 10 is provided instead of the colored layer (BM) 8 between the top of the 4P and the display surface side transparent substrate 2, the pixel partition 4P without the colored layer (BM) 8 is provided on the panel display surface. Depending on the cross-sectional area, the light collection rate of the reflected light from the display medium is high. , To improve the brightness. Therefore, an information display panel in which the brightness of the panel display surface is improved can be provided.

  Hereinafter, each member which comprises the information display panel used as the object of this invention is demonstrated.

  As for the substrate, the display surface side substrate is a transparent substrate on which the color of the 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 back substrate may be transparent or opaque. Examples of the substrate include inorganic substrates such as glass and ceramics, polyethylene terephthalate (PET), polyethylene terephthalate (PEN), polyethylene (PE), polycarbonate (PC), polyimide (PI), and polyethersulfone (PES). Organic polymer substrates such as acrylic can be used. 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 spacing uniformity between the substrates, and if it is thicker than 5000 μm, it will be a thin information 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. The electrode can be formed by patterning the above-described materials into a thin film by sputtering, vacuum deposition, CVD (chemical vapor deposition), coating, or the like, or by mixing a conductive agent with a solvent or synthetic resin binder. A method of applying and patterning is used. The electrode provided on the viewing side (display surface 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 display surface 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 shape of the partition provided on the substrate is appropriately set according to the type of display medium involved in display, the shape and arrangement of the electrodes to be arranged, and is not generally limited. However, the width of the partition is 2 to 100 μm, preferably 3 The height of the partition wall is adjusted to 10 to 100 μm, preferably 10 to 50 μm.
In forming the partition wall, a both-rib method in which ribs are formed on each of the opposing substrates 1 and 2 and then bonded, and a single-rib method in which ribs are formed only on one substrate are conceivable. In the present invention, any method is preferably used.
As shown in FIG. 8, the cells (unit cells and pixels) formed by the partition walls made up of these ribs are illustrated in a square shape, a triangular shape, a line shape, a circular shape, and a hexagonal shape as viewed from the substrate plane direction. Is exemplified by a lattice shape, a honeycomb shape, or a mesh shape. It is better to make the portion corresponding to the cross section of the partition wall visible from the display surface side (the area of the cell frame) as small as possible, and the display becomes clearer.
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. Any of these methods can be suitably used for the information display panel of the present invention, and among these, a photolithography method using a resist film and a mold transfer method are suitably used.

  Next, the powder fluid used as a display medium in the information display panel of the present invention will be described. As for the name of the powder fluid used in the information display panel of the present invention, the present applicant has obtained the right of “Electronic Powder Fluid (registered trademark): Registration No. 4636931”.

  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, in a dispersion system in which a solid or liquid substance is stably suspended as a dispersoid in a gas, and the solid substance is regarded as a dispersoid in the information display panel of the present invention. To do.

The information display panel 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, in a gas, between opposed substrates, at least one of which is transparent. In addition, such a powder fluid can be easily and stably moved by a Coulomb force or the like with a small electric field.
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 information display panel of the present invention, it is used as a display medium in a state where a solid substance floats relatively stably as a dispersoid in the gas.

Next, display medium particles (hereinafter also referred to as particles) constituting the display medium in the information display panel of the present invention will be described. The display medium particles are composed of the display medium particles as they are to form a display medium, or are combined with other particles to form a display medium, or adjusted and configured to become a powder fluid to form a display medium. Or used.
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 for display media of the present invention (hereinafter also referred to as particles) 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. If the average particle diameter d (0.5) is smaller than this range, the cohesive force between the particles becomes too large, which hinders movement as a display medium.

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 display medium 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. 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 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.

Furthermore, when applying a display medium such as a particle group composed of particles for a display medium or a powdered fluid to a dry information display panel, it is important to manage the gas in the void surrounding the display medium between the substrates, Contributes to improved display stability. Specifically, it is important that the relative humidity at 25 ° C. is 60% RH or less, and preferably 50% RH or less for the humidity of the gas in the gap.
1, 2, 3 (a) and (b), electrodes 5 and 6 (when the electrodes are provided inside the substrate) from the portion sandwiched between the opposing substrate 1 and substrate 2 in FIG. ), A gas portion in contact with a so-called display medium excluding an occupied portion of the display medium 3, an occupied portion of the partition walls 4, 4U and 4P, and a seal portion of the information display panel.
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 an information display panel so that the humidity is maintained, for example, filling a display medium, assembling an information display panel in a predetermined humidity environment, It is important to apply a sealing material and a sealing method that prevent moisture from entering from the outside.

The distance between the substrates in the information display panel that is the subject of the present invention is not limited as long as the 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.
The volume occupation ratio of the display medium 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 display medium is hindered, and when it is less than 5%, the contrast tends to be unclear.

  The information display panel of the present invention has no image unevenness, display parts 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. Suitable for display units for calculators, home appliances, automotive products, card display units such as point cards and IC cards, electronic advertisements, electronic POPs, electronic shelf labels, electronic price tags, electronic musical scores, and display units for RF-ID devices Used for.

It is a figure which shows an example of the information display panel used as the object of this invention. It is a figure which shows the other example of the information display panel used as the object of this invention. (A), (b) is a figure which shows the structural example of the information display panel of the color display correspondence type of this invention. It is a figure which shows the 1st example of the condensing rate improvement measure of the reflected light from the display medium of the information display panel of this invention. It is a figure which shows the 2nd example of the condensing rate improvement measure of the reflected light from the display medium of the information display panel of this invention. It is a figure which shows the 3rd example of the condensing rate improvement measure of the reflected light from the display medium of the information display panel of this invention. It is a figure which shows the 4th example of the condensing rate improvement measure of the reflected light from the display medium of the information display panel of this invention. It is a figure which shows an example of the shape of the partition in the information display panel used as the object of this invention. It is a figure which shows the structure of the color display corresponding | compatible information display panel of a prior art example.

Explanation of symbols

1 Substrate (Display side transparent substrate)
2 Substrate (Back side substrate)
3 Display media (particle group, powder fluid)
3W White display medium 3B Black display medium 3Wa White display medium particle 3Ba Black display medium particle 4 Partition 4U Unit cell partition 4P Pixel partition 5 Electrode 6 Electrode 7R, 7G, 7B Transparent color filter 8 Color layer (Black matrix; BM)
9 Space 10 White layer

Claims (4)

Each of the plurality of unit cells partitioned by the partition between the two substrates is composed of three pixels, and a transparent color filter of the three primary colors is arranged for each pixel on the transparent substrate side. In an information display panel for displaying information such as images in color by moving a black and white two-color display medium enclosed between air and air,
A colored layer is provided between the top of the partition wall constituting the unit cell and the display surface side transparent substrate, and no colored layer is provided between the top of the partition wall forming the pixel and the display surface side transparent substrate. Information display panel.   The information display panel according to claim 1, wherein a predetermined space is provided between the top of the partition wall forming the pixels not provided with the colored layer and the display surface side transparent substrate.   2. The information display panel according to claim 1, wherein a white layer is provided between the top of the partition wall forming a pixel without a colored layer and the display surface side transparent substrate.   The information display panel according to claim 1, wherein the colored layer is a black matrix.

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