JP2009145433A - Panel for information display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a panel for information display adapted to obtain desired display performance by optimizing a thickness of linear electrodes used in a dot matrix type passive driving system based on the mean particle diameter of particles constituting a display medium. <P>SOLUTION: The panel for information display includes sealing the display medium 3 composed of two kinds of particle groups 3W, 3B constituted by including particles having optical reflectivity, and chargeability into a cell formed by partitions 4 between substrates 1, 2, applying an electric field to the display medium 3 from paired electrodes formed by crossing of the linear electrodes 5, 6 respectively disposed at the two substrate, and displaying information, such as an image. by transferring the display medium 3. A thickness Et of the linear electrodes 5, 6 is set at a thickness below the mean particle diameter D1 which is smaller than the mean particle diameter of the particle group 3W or the particle group 3B and over 5 nm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, at least two kinds of display media composed of particles having optical reflectivity and chargeability are enclosed in a space between two substrates, at least one of which is transparent, and the two substrates are enclosed. The present invention relates to an information display panel for displaying information such as an image by moving an electric field to a display medium from a counter electrode formed by intersecting line electrodes provided to the display medium. is there.

  As a dot matrix type information display device that replaces a liquid crystal display (LCD), a method of moving particles in a gas (for example, an electronic powder fluid method), a method of moving particles in a liquid (electrophoresis method), an electrochromic method, An information display device using an information display panel using a technique such as a thermal method or a two-color particle rotation method has been proposed.

  Compared with liquid crystal information display panels used in LCDs, these conventional information display panels can provide a wide viewing angle close to that of ordinary printed materials, have low power consumption, and have a memory function. Because of its merit, it is considered as an information display panel that can be used in the next generation of inexpensive information display devices, and is expected to be used for information display for mobile terminals, electronic paper, and the like.

  Among the various next-generation information display panels described above, a display medium comprising a particle group comprising particles having optical reflectivity and chargeability in a space between two substrates, at least one of which is transparent Information for displaying information such as images by moving at least two types of display media by applying electric fields to at least two types of display media from line-shaped electrodes provided on two substrates, respectively, enclosed in at least two types Since the display panel has excellent display memory characteristics (bistable characteristics) and has a driving threshold value, the information display panel of the dot matrix type passive drive system in which the counter electrodes are composed of line electrodes that cross each other at right angles And is expected to be cheaper than an information display panel of an active drive system (see, for example, Patent Document 1).

JP 2006-58643 A

  The counter electrode provided in the information display panel having the above-described structure is provided on each of the opposing substrates. At this time, the electrode is formed on the inner surface of the substrate so that the electrode and the display medium are in contact with each other, or the electrode is extremely thin. An electrode is coated with a film (for example, an insulating film). In either case, since the electrode portion is convex with respect to the substrate surface, the electrode surface and the substrate surface are not smooth, and a dent occurs between the electrodes. In addition, the counter electrode used in the dot matrix type passive drive system is arranged so that the line electrodes are opposed and orthogonal to each other, but the electrical resistance of the line electrodes changes according to the thickness of these line electrodes. If the thickness of the line-shaped electrode is not optimized, there arises a problem that display image quality (for example, contrast) varies and a problem in display performance. That is, if the line-shaped electrode is too thin, the electric resistance of the line-shaped electrode becomes high, and a voltage drop causes a difference in voltage depending on the electrode position, resulting in a malfunction in display performance and a change in the applied voltage waveform. This causes a problem with display performance. In addition, when the space in the cell in which the particles move is filled with a gas containing oxygen such as air or when it is filled with a gas containing moisture, the line electrode will undergo oxidative degradation. If the line-shaped electrode is too thin, the effect of oxidative deterioration will appear immediately, resulting in poor display performance. On the other hand, if the line-shaped electrode is too thick, the particles used as the display medium are buried between the line-shaped electrodes and cannot move, causing a problem in display performance.

  The present invention is for information display in which a desired display quality can be obtained by optimizing the thickness of the line electrode used in the dot matrix type passive drive system based on the average particle diameter of particles used as a display medium. The purpose is to provide a panel.

  In order to achieve the above object, an information display panel according to claim 1 of the present invention forms a plurality of cells partitioned by a partition wall between two substrates, at least one of which is transparent, and optically contains the cells. An electric field is applied to the display medium from the counter electrode formed by intersecting at least two types of display media composed of particles having a reflectance and a chargeability and including line electrodes provided on two substrates. The information display panel displays information such as an image by moving the at least two types of display media, and each of the thicknesses of the line-shaped electrodes and the at least two types of display media. In relation to the average particle diameter of the particle group, the thickness of each line electrode is made smaller than the smallest average particle diameter among the average particle diameters of the respective particle groups as the at least two kinds of display media. It is characterized in.

  In order to achieve the above object, an information display panel according to claim 2 of the present invention is formed by forming a plurality of cells partitioned by a partition wall between two substrates, at least one of which is transparent, in the cell. At least two types of display media composed of a particle group including particles having reflectivity and chargeability are sealed, and a counter electrode formed by intersecting line electrodes respectively provided on two substrates is used as a display medium. An information display panel for displaying information such as images by moving the at least two types of display media by applying an electric field, wherein the thickness of each line-shaped electrode and the at least two types of display media In relation to the optical reflectance and the average particle diameter of the particles having charging properties included in each particle group, the optical reflectance and charging properties included in each particle group as the at least two kinds of display media are as follows. Than the smallest average particle size of the average particle size of the particles, characterized in that to reduce the thickness of each line-shaped electrodes.

  As a suitable example of the information display panel of the present invention, the thickness of each line-shaped electrode is larger than 5 nm, and the arrangement of cells formed by the partition walls corresponds to the arrangement of the line-shaped electrodes.

  According to the information display panel of the first aspect of the present invention, a plurality of cells partitioned by partition walls are formed between two substrates, at least one of which is transparent, and the optical reflectance and charging are formed in the cells. Encapsulating at least two types of display media composed of particles having the properties of particles, and applying an electric field to the display media from counter electrodes formed by intersecting line electrodes provided on two substrates, respectively. In the information display panel for displaying information such as images by moving the at least two types of display media, the thickness of each line electrode and the average particle diameter of each particle group as the at least two types of display media Since the thickness of each line-shaped electrode is smaller than the smallest average particle diameter among the average particle diameters of the respective particle groups as the at least two kinds of display media, The thickness of the line electrode used in the Tricks type passive drive system is optimized based on the average particle diameter of the particle group as the display medium, and the particles as the display medium are used when the line electrode is too thick. The problem is that the group is buried between the line electrodes and cannot move, causing problems in display performance, or the line electrode is too thin. The display performance may be affected due to the difference in the display voltage, the applied voltage waveform may change and the display performance may be impaired, or the space in the cell where the particles move may be filled with a gas containing oxygen such as air or wet. When filled with a gas containing a minute, it is possible to prevent a problem that the effect of oxidative deterioration immediately appears on the line-shaped electrode and causes a problem in display performance. Therefore, it is possible to provide an information display panel that can obtain desired display performance.

  According to the information display panel of the second aspect of the present invention, a plurality of cells partitioned by a partition wall are formed between two substrates, at least one of which is transparent, and the optical reflectance and charging are formed in the cells. At least two types of display media, each of which is composed of a group of particles including a conductive particle, and an electric field is applied to the display medium from a counter electrode formed by intersecting line electrodes provided on two substrates, respectively. Accordingly, in the information display panel for displaying information such as an image by moving the at least two types of display media, the thickness of each line electrode and the optics included in each particle group as the at least two types of display media In terms of the relationship between the average reflectance and the average particle diameter of the particles having charging properties, the average particle diameter of the particles having optical reflectance and charging properties included in each of the particle groups as the at least two types of display media is used. Since the thickness of each line-shaped electrode is smaller than the smallest average particle diameter among the particle diameters, the thickness of the line-shaped electrode used in the dot matrix type passive drive system includes each particle group used as at least two types of display media. It is optimized based on the average particle diameter of the particles having the optical reflectivity and the chargeability, and the optical reflectivity included in each particle group as the display medium and the case where the line-shaped electrode is too thick, and Due to the voltage drop caused by the high electrical resistance of the line electrode, such as when the charged particles are buried between the line electrodes and cannot move and the display performance is defective, or the line electrode is too thin. There is a problem in display performance due to a difference in voltage depending on the electrode position, a problem in display performance due to a change in the applied voltage waveform, or in the cell where particles move. When the gap is filled with a gas containing oxygen such as air or with a gas containing moisture, it is possible to prevent the problem that the effect of oxidative degradation immediately appears on the line-shaped electrode and causes a malfunction in the display performance. . Therefore, it is possible to provide an information display panel that can obtain desired display performance.

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

  First, an example of the information display panel of the present invention will be described. In the information display panel according to the present invention, an electric field is applied to a display medium composed of at least two types of particle groups including charged particles having optical reflectivity sealed in a space between two opposing substrates. The Along with the applied electric field direction, the display medium is attracted by an electric field force or a Coulomb force, and the display medium is moved by a change in the electric field direction, whereby information such as an image is displayed. Therefore, it is necessary to design the information display panel so that the display medium can move uniformly and maintain the stability when the display information is rewritten or when the display information is continuously displayed. 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. 1 (a) and (b) to FIGS. 3 (a) and 3 (b).

  In the example shown in FIGS. 1A and 1B, at least two types of display media 3 (here, white for display media) each composed of a group of particles including particles having different optical reflectivities and charging characteristics. A white display medium 3W composed of a particle group composed of charged particles 3Wa and a black display medium 3B composed of a particle group composed of black charged particles 3Ba for display medium). This is generated by applying a voltage between the counter electrode formed by the electrode 5 (line electrode) provided on the substrate 1 and the electrode 6 (line electrode) provided on the substrate 2 crossing each other in the gas space. The substrate is moved perpendicular to the substrates 1 and 2 in accordance with the electric field to be applied. Then, as shown in FIG. 1A, the white display medium 3W is visually recognized by the observer and white dot display is performed, or as shown in FIG. 1B, the black display medium 3B is visually recognized by the observer. Black dots are displayed. In addition, in FIG. 1 (a), (b), the partition in front is abbreviate | omitted. The electrode is provided inside the substrate, but the electrode may be exposed or coated with another material. When the electrode is coated with another material, an appropriate material is used in consideration of electrical properties such as dielectric constant and conductivity insulation and adhesion to particles in the cell.

  In the example shown in FIGS. 2 (a) and 2 (b), at least two or more types of display media 3 (here, white for display media) each composed of a particle group containing particles having different optical reflectivities and charging characteristics. A white display medium 3W composed of a particle group composed of charged particles 3Wa and a black display medium 3B composed of a particle group composed of black charged particles 3Ba for display medium). Between the counter electrodes formed by the electrodes 5 (line electrodes) provided on the substrate 1 and the electrodes 6 (line electrodes) provided on the substrate 2 crossing each other at right angles in the middle space of the insulating liquid filled with the insulating transparent liquid 7. The substrate is moved perpendicularly to the substrates 1 and 2 in accordance with an electric field generated by applying a voltage to the substrate. Then, as shown in FIG. 2 (a), the white display medium 3W is visually recognized by the observer and white dot display is performed, or as shown in FIG. 2 (b), the black display medium 3B is visually recognized by the observer. Black dots are displayed. In addition, in FIG. 2 (a), (b), the partition in front is abbreviate | omitted. The electrode is provided inside the substrate, but the electrode may be exposed or coated with another material. When the electrode is coated with another material, an appropriate material is used in consideration of electrical properties such as dielectric constant and conductivity insulation and adhesion to particles in the cell.

  In the example shown in FIGS. 3A and 3B, an example of color display in which a display unit (1 dot) is constituted by three cells is shown. In the example shown in FIGS. 3A and 3B, as the display medium, all of the cells 21-1 to 21-3 are filled with the white display medium 3W and the black display medium 3B, and the first cell 21-1. A red color filter 22R is provided on the viewer side, a green color filter 22G is provided on the viewer side of the second cell 21-2, a blue color filter 22B is provided on the viewer side of the third cell 21-3, A display unit (one dot) is composed of three cells, the first cell 21-1, the second cell 21-2, and the third cell 21-3. In this example, when performing color display, as shown in FIG. 3A, the white display medium 3W is moved in the first cell 21-1 to the third cell 21-3 to the viewer side. Thus, white dots are displayed to the observer, or, as shown in FIG. 3B, the black color is displayed in all of the first cell 21-1 to the third cell 21-3 on the observer side. By moving the medium 3B, black dots are displayed to the observer. In addition, in FIG. 3 (a), (b), the partition in front is abbreviate | omitted. Multicolor display can be performed by moving the display medium in each cell.

  The information display panel of the present invention will be described in detail below. The information display panel of the present invention forms a plurality of cells partitioned by a partition between two substrates, at least one of which is transparent, and each of the cells has particles having different optical reflectance and charging characteristics. By enclosing at least two or more kinds of display media composed of the contained particles, and applying an electric field to the display media from the counter electrodes formed by intersecting line electrodes provided on the two substrates, respectively, at least 2 It is an information display panel that displays information such as images by moving various types of display media, and the thickness of each line electrode (the line electrode 5 provided on the substrate 1 and the line electrode 6 provided on the substrate 2) is Each particle group having a thickness based on the average particle diameter of each particle group serving as a display medium or each of the particles having optical reflectivity and chargeability contained in each particle group serving as a display medium It is characterized by being set on the basis of the thickness based on.

The thickness of the line-shaped electrode 5 and the line-shaped electrode 6 is Et, and the minimum average particle diameter of the particle groups constituting each display medium as at least two types of display media is D1, and at least two types When the minimum average particle diameter among the average particle diameters of the chargeable particles included in the particle group constituting each display medium as the display medium is D2, the thickness Et of the line electrode 5 and the line electrode 6 is:
5 nm <Et <D1 5 nm <Et <D2- (1)
It is preferable that
If the line-shaped electrodes 5 and 6 are too thin (for example, if the thickness Et of the line-shaped electrodes 5 and 6 is less than 5 nm (50 mm)), the electric resistance of the line-shaped electrodes increases, and the voltage drop causes a voltage depending on the electrode position. A difference occurs, causing a display performance problem and a change in the applied voltage waveform, resulting in a problem in the display performance. In addition, when the space in the cell in which the particles move is filled with a gas containing oxygen such as air or when it is filled with a gas containing moisture, the line electrode will undergo oxidative degradation. If the line-shaped electrode is too thin (for example, if the thickness Et of the line-shaped electrodes 5 and 6 is less than 5 nm (50 mm)), the influence of oxidative deterioration will be immediately produced, resulting in a problem in display performance. On the other hand, if the line electrodes 5 and 6 are too thick (thickness Et of the line electrodes 5 and 6 is the smallest average particle among the average particle diameters of the particle groups constituting each display medium having at least two types of display media) Exceeding the diameter D1 (for example, 5 μm) or exceeding the minimum average particle diameter D2 (for example, 5 μm) among the average particle diameters of the charged particles included in the particle group constituting each of the display media as at least two types of display media Then, particles constituting each of the display media as at least two types of display media are buried between the line-shaped electrodes and cannot move, causing a problem in display performance.
Of the line-shaped electrodes 5 and 6, at least the electrode that is not provided on the display surface side is preferably a metal electrode in order to keep the electric resistance of the line-shaped electrode low. The thickness of the line electrodes 5 and 6 may be the same or different, and the material of the line electrodes 5 and 6 may be the same or different. In addition, the arrangement of the cells formed by the partition walls and the layout of the line-shaped electrodes correspond to each other (in the case where the electrodes 5 and 6 are line-shaped electrodes intersecting each other, the partition walls are arranged in a lattice pattern). This is preferable in preventing the movement of particles from one cell to another.

  According to the information display panel of the present invention, the thickness of the line-like electrode 5 and the line-like electrode 6 is Et, and the smallest among the average particle diameters of the particle groups constituting each display medium as at least two kinds of display media. When the average particle diameter of each of the charged particles included in the particle group constituting each of the display media as D1 is D2, and the average particle diameter of the line-shaped electrode 5 is D2. Since the thickness Et of the line electrode 6 is set to 5 nm <Et <D1 5 nm <Et <D2, the thickness of the line electrode used in the dot matrix type passive drive system is at least two types of display media. The average particle diameter of the chargeable particles contained in the particle group constituting the display medium or the particle group constituting each display medium as at least two kinds of display media Each of the particle groups constituting at least two types of display media or at least two types of display media, as in the case where the line-shaped electrode is too thick. The electrical resistance of the line electrode is such that the charged particles contained in the particle group constituting the medium are buried between the line electrodes and cannot move and the display performance is deteriorated, or the line electrode is too thin. A voltage drop caused by the voltage drop causes a difference in voltage depending on the electrode position, resulting in a malfunction in the display performance, a problem in the display performance due to a change in the applied voltage waveform, and air in the cell space where the particles move Prevents the problem of display performance failure due to immediate effect of oxidative degradation on the line electrode when filled with gas containing oxygen or with gas containing moisture. Rukoto can. Therefore, it is possible to provide an information display panel that can obtain desired display performance.

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

  As the substrate, at least one 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 as the other substrate may be transparent or opaque. Examples of substrate materials include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethylene (PE), polycarbonate (PC), polyimide (PI), polyethersulfine (PES), acrylic polymer substrates Alternatively, a glass sheet, a quartz sheet, a metal sheet, or the like is used, and a transparent one is used on the display surface side. The thickness of the substrate is preferably 2 to 2000 μm, more preferably 5 to 1000 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 2000 μm, it will be a thin information display panel. Is inconvenient.

  Materials for forming electrodes provided on the substrate include metals such as aluminum, silver, nickel, copper, and gold, indium tin oxide (ITO), zinc aluminum oxide (AZO), indium oxide, conductive tin oxide, and zinc-doped indium oxide. Examples thereof include conductive metal oxides such as (IZO), antimony tin oxide (ATO), and conductive zinc oxide, and conductive polymers such as polyaniline, polypyrrole, and polythiophene. As an electrode forming method, the above-exemplified materials are patterned into a thin film by sputtering, vacuum deposition, CVD (chemical vapor deposition), coating, or the like, or a metal foil (for example, rolled copper foil) is laminated. A method or a method of patterning by mixing a conductive agent with a solvent or a synthetic resin binder and applying it 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. The thickness of the electrode is not limited as long as the conductivity can be secured and the light transmittance is not affected, and is within the range of 0.005 to 10 μm. The charging included in the particle group constituting each display medium used for at least two types of display media. It is set to a suitable thickness from the relationship with the average particle size of the active particles or the relationship with the average particle size of the particle group constituting each display medium used in at least two types of display media. The material, thickness, and the like 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 it is not necessary to consider light transmittance. 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, a single rib method in which ribs are formed only on the upper substrate is preferably used.
As shown in FIG. 4, the cells 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. In the present invention, a lattice arrangement is preferable, and a square and lattice arrangement is more preferable. 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 an information display panel mounted on the information display device of the present invention, and among these, a photolithography method using a resist film and a mold transfer method are suitably used.

Next, the chargeable particles having the optical reflectance included in the particle group constituting the display medium in the information display panel which is the subject of the present invention will be described. The particles (also referred to as display medium particles) are particles having optical reflectivity and chargeability, and are used as a display medium as a group of particles composed solely of the display medium particles, or combined with other particles. The particles are used as a display medium.
The particles for display medium can contain a charge control agent, a colorant, an inorganic additive, and the like, if necessary, in the resin as the main component. 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 above colorant can be blended to produce display medium particles having a desired color.

  The particles for display medium (hereinafter also referred to as particles) have an average particle diameter d (0.5) in the range of 1 to 50 μm, and are preferably 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 display medium 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 sizes of the particles for the display medium are uniform, and movement as a uniform display medium becomes possible.

  Furthermore, regarding the correlation of each display medium particle, among the display medium particles used, the ratio of d (0.5) of the display medium particles having the minimum diameter to d (0.5) of the display medium particles having the maximum diameter. It is important to set the value to 10 or less. Even if the particle size distribution Span is reduced, the display medium particles having different charging characteristics move in opposite directions, so that the display medium particles are close in size, and the display medium particles are equivalent in opposite directions. It is preferable that it can be easily moved, and this is the range.

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

Furthermore, in the case of an information display panel that drives the display medium in the air space, it is important to manage the gas in the gap surrounding the display medium 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, and preferably 50% RH or less for the humidity of the gas in the gap.
The voids are occupied by the electrodes 5 and 6 and the display medium 3 from the part sandwiched between the opposing substrate 1 and substrate 2 in FIGS. 1 (a), 1 (b) to 3 (a), (b). A gas portion in contact with a so-called display medium excluding the portion, the occupied portion of the partition wall 4 and the seal portion of the information display panel 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 an information display panel so that the humidity is maintained, for example, filling a display medium, assembling an information display panel, etc. 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 100 μm, preferably 10 to 50 μm.
The volume occupancy of the display medium when the space between the opposing substrates is a gas space is preferably 5 to 70%, more preferably 5 to 60%. When it exceeds 70%, the movement as a display medium is hindered, and when it is less than 5%, the contrast tends to be unclear.

  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 the following examples and comparative examples, “average particle diameter of display medium particles (charged particles) contained in a particle group as a display medium” is described as the average particle diameter. The average particle diameter (average particle diameter in a state where charged particles and external additive particles are mixed) "was measured, and the results were almost the same. The external additive particles constituting the particle group together with the charged particles are particles having a nanometer class particle size, and the average particle size measured as an integral particle attached to the charged particles is slightly increased, but the particles are not attached to the charged particles. Those independently present are measured so that the average particle size is slightly smaller, and as a result, the measured average particle size is almost the same with or without the external additive particles.

<Example 1>
As the display medium 3, a white display medium 3W comprising a particle group including white negatively chargeable particles 3Wa for display medium having an average particle diameter of 10.2 μm and black positively chargeable particles for display medium having an average particle diameter of 9.4 μm While using a black display medium 3B composed of a particle group including 3Ba, a back side electrode (line electrode having a gap of 20 μm between electrodes) 5 provided on the substrate 1 and a display surface side electrode (line shape) provided on the substrate 2 As an electrode 6, an ITO electrode having a thickness of 100 nm and a surface resistivity of 15 Ω / □ was used as a counter electrode so as to be opposed to each other, and the charged particle movement type information display panel of Example 1 shown in FIG. Produced. At this time, the partition walls (ribs) 4 are provided in a lattice shape, but the display units formed by the counter electrodes do not correspond to the positions of the cells surrounded by the partition walls (ribs). In this information display panel, the thickness of the line electrodes used in the dot matrix type passive drive system is optimized based on the average particle diameter of the particles constituting the display medium. The presence or absence of particles stuck in the gap was visually confirmed with a microscope at 50 times magnification. As a result, there was no particle in the gap between the line-shaped electrodes, and the particles serving as the display medium appeared in the adjacent cell surrounded by the partition walls. Durability at the time of repeating rewriting display was improved without moving. Also, using an optical densitometer (RD918, manufactured by Gretagmass Beth), the image reflection density Dw when displaying a white solid image and the image reflection density Db when displaying a black solid image are measured, and the ratio between the two When (Db / Dw) is defined as the display contrast, the initial display contrast is 10, the display contrast after rewriting 10,000 times is 8, and a good display performance without lowering the display contrast can be obtained. It was.

<Example 2>
As the display medium 3, a white display medium 3W comprising a particle group including white negatively chargeable particles 3Wa for display medium having an average particle diameter of 10.2 μm and black positively chargeable particles for display medium having an average particle diameter of 9.4 μm Using a black display medium 3B composed of particles composed of 3Ba, a copper-plated electrode having a thickness of 3 μm is used as a back-side electrode (line electrode having a gap between electrodes of 20 μm) 5 provided on the substrate 1. In addition, as the display surface side electrode (line electrode) 6 provided on the substrate 2, an ITO electrode having a thickness of 200 nm is formed using an ITO material having a thickness of 100 Ω and a surface resistivity of 15Ω / □, and the counter electrode is formed so as to be opposed to each other. Thus, an information display panel of the charged particle movement type of Example 2 shown in FIG. 6 was produced. At this time, the partition walls (ribs) 4 are provided in a lattice shape, but the display units formed by the counter electrodes do not correspond to the positions of the cells surrounded by the partition walls (ribs). In this information display panel, the thickness of the line electrodes used in the dot matrix type passive drive system is optimized based on the average particle diameter of the particles constituting the display medium. The presence or absence of particles stuck in the gap was visually confirmed with a microscope at 50 times magnification. As a result, there was no particle in the gap between the line-shaped electrodes, and the particles serving as the display medium appeared in the adjacent cell surrounded by the partition walls. Durability at the time of repeating rewriting display was improved without moving. Also, using an optical densitometer (RD918, manufactured by Gretagmass Beth), the image reflection density Dw when displaying a white solid image and the image reflection density Db when displaying a black solid image are measured, and the ratio between the two When (Db / Dw) is defined as the display contrast, the initial display contrast is 12, and the display contrast after 10,000 rewrites is 10, so that a good display performance without lowering the display contrast can be obtained. It was.

<Comparative Example 1>
As the display medium 3, a white display medium 3W comprising a particle group including white negatively chargeable particles 3Wa for display medium having an average particle diameter of 10.2 μm and black positively chargeable particles for display medium having an average particle diameter of 9.4 μm A black display medium 3B composed of a particle group including 3Ba is used, and an electrode having a thickness of 12 μm laminated with a copper foil is used as a back-side electrode (line electrode having a gap between electrodes of 20 μm) 5 provided on the substrate 1. In addition, as a display surface side electrode (line electrode) 6 provided on the substrate 2, an ITO electrode having a thickness of 100 nm and an ITO material having a surface resistivity of 15Ω / □ is formed, and a counter electrode is formed so as to be opposed to each other and orthogonal to each other. Thus, an information display panel of the charged particle movement type of Comparative Example 1 shown in FIG. 7 was produced. At this time, since the partition walls (ribs) 4 are provided in a honeycomb shape, the display units formed by the counter electrodes do not correspond to the positions of the cells surrounded by the partition walls (ribs). Since this information display panel has a gap deeper than the average particle diameter of the particles as shown in the figure between the electrodes 5 and 5, the movement of the particles between the cells surrounded by the partition wall after repeated rewriting display In the middle of the evaluation test, the presence or absence of particles that enter the gap between the line-shaped electrodes and visually stopped is visually confirmed by a 50 × magnification with a microscope, and there are a large amount of particles in the gap between the line-shaped electrodes. The display contrast has dropped significantly. As a result, the initial display contrast was 12, but the display contrast after rewriting 10,000 times was reduced to 1.5, and the display performance was significantly reduced.

<Comparative example 2>
As the display medium 3, a white display medium 3W comprising a particle group including white negatively chargeable particles 3Wa for display medium having an average particle diameter of 10.2 μm and black positively chargeable particles for display medium having an average particle diameter of 9.4 μm Using a black display medium 3B composed of particles composed of 3Ba and using a 5 nm thick electrode obtained by sputtering copper as a back side electrode (line electrode having a gap between electrodes of 20 μm) 5 provided on the substrate 1 As the display surface side electrode (line electrode) 6 provided on the substrate 2, an ITO electrode having a thickness of 100 nm and a surface resistivity of 15 Ω / □ is formed, and an ITO electrode having a thickness of 5 nm is formed. A charged particle movement type information display panel of Comparative Example 2 shown in FIG. 8 was prepared. At this time, the partition walls (ribs) 4 are provided in a lattice shape, but the display units formed by the counter electrodes do not correspond to the positions of the cells surrounded by the partition walls (ribs). This information display panel had poor display medium drivability because the electric resistance of the electrodes 5 and 6 was large, the initial display contrast was 2, and only a display contrast that was not practically sufficient was obtained.

  Consider the phenomenon that particles get stuck in the gap between line electrodes. When an information display panel is manufactured by combining the line-shaped electrode 5 shown in FIG. 9A and the quadrangular lattice-shaped partition walls 4 shown in FIG. 9B, the opposing line-shaped electrodes (line-shaped electrode 5 and line The display unit formed by the electrode 6) does not correspond to the position of the cell surrounded by the partition wall 4, and there is a gap 8 between adjacent line electrodes as shown in FIG. 9C. Become. In addition, when an information display panel is manufactured by combining the line-shaped electrode 5 shown in FIG. 10A and the honeycomb-shaped partition walls 4 shown in FIG. 10B, the opposed line-shaped electrodes (line-shaped electrode 5 and The display unit formed by the line electrode 6) does not correspond to the position of the cell surrounded by the partition wall 4, and there is a gap 8 between adjacent line electrodes as shown in FIG. become.

  In the case of the configuration shown in FIGS. 5 to 8, the gap portion 8 as described above exists, but in the case of Example 1 shown in FIG. 5, the case of Example 2 shown in FIG. 6 and the comparison shown in FIG. 8. In the case of Example 2, the average particle diameter (9.4 μm, 10.2 μm) of the particles is smaller than the width of the gap portion 8 (for example, 20 μm), and the depth of the gap portion 8 is smaller than the average particle diameter (that is, The thickness of the line-shaped electrode; 100 nm, 3 μm, 5 nm) is small, so that the particles do not move into the gap portion 8. On the other hand, in the case of Comparative Example 1 shown in FIG. 7, the average particle diameter (9.4 μm, 10.2 μm) of the particles is smaller than the width of the gap portion 8 (for example, 20 μm), and the gap is smaller than the average particle diameter. Since the depth of the portion 8 (that is, the thickness of the line electrode: 12 μm) is large, the particles enter the gap portion 8 and do not move. In the case of the comparative example 2 shown in FIG. 8, the problem that the particles move into the gap portion 8 is avoided. However, since the thickness of the line electrodes 5 and 6 is 5 nm and 5 nm or less, the same. Even in the case of the line electrodes 5 and 6 formed of an electrode material having surface resistance, there is a problem that the electric resistance increases and the display medium drivability deteriorates.

The information display panel of the present invention includes a notebook computer, an electronic notebook, a portable information device called PDA (Personal Digital Assistants), a display unit of a mobile device such as a mobile phone, a handy terminal, an electronic book, an electronic newspaper, an electronic manual ( Electronic manuals), electronic paper such as signboards, posters, bulletin boards such as blackboards and whiteboards, electronic desk calculators, display units for home appliances, automobile supplies, card display units such as point cards and IC cards, electronic advertisements, In addition to information boards, electronic POPs (Point Of Presence, Point Of Purchase advertising), electronic price tags, electronic shelf labels, electronic musical scores, and display units for RF-ID devices, various electronic devices such as POS terminals, car navigation devices, watches, etc. It is suitably used for the display unit. In addition, it can be suitably used as a display unit (so-called rewritable paper) for rewriting the display by an external electric field forming unit.
Although the technology of the present invention has been described for the information display panel of the simple matrix driving method in which the line electrode is provided and no switching element is used in the panel itself, it can be applied to a driving method such as an active driving method or a static driving method. .

(A), (b) is a figure which shows the principle structure of the information display panel used as the object of this invention. (A), (b) is a figure which shows the principle structure of the information display panel used as the object of this invention. (A), (b) is a figure which shows the principle structure of the information display panel used as the object 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 information display panel of Example 1 of this invention. It is a figure which shows the structure of the information display panel of Example 2 of this invention. It is a figure which shows the structure of the information display panel of the comparative example 1 of this invention. It is a figure which shows the structure of the information display panel of the comparative example 2 of this invention. (A)-(c) is a figure for demonstrating the relationship between the clearance gap part between adjacent line-shaped electrodes and particle | grains in the Example and comparative example of this invention. (A)-(c) is a figure for demonstrating the relationship between the clearance gap part between adjacent line-shaped electrodes and particle | grains in the Example and comparative example of this invention.

Explanation of symbols

1, 2 Substrate 3 Display medium (particle group)
3W White display medium 3B Black display medium 3Wa White charged particles for display medium 3Ba Black charged particles for display medium 4 Bulkhead 5, 6 Electrode 7 Insulating transparent liquid 8 Gap portion 21-1 First cell 21-2 Second cell 21 -3 Third cell 22R Red color filter 22G Green color filter 22B Blue color filter

Claims (4)

At least a display medium comprising a group of particles formed by forming a plurality of cells partitioned by a partition between two substrates, at least one of which is transparent, and containing particles having optical reflectivity and chargeability in the cells. By applying an electric field to the display medium from a counter electrode formed by intersecting and forming two types of line electrodes provided on two substrates, the information on an image or the like is moved. An information display panel for displaying
In the relationship between the thickness of each line electrode and the average particle diameter of each particle group used as the at least two types of display media, the smallest average among the average particle diameters of each particle group used as the at least two types of display media. An information display panel, wherein the thickness of each line electrode is made smaller than the particle diameter. A display medium comprising a group of particles formed by forming a plurality of cells partitioned by a partition wall between two substrates, at least one of which is transparent, and containing particles having optical reflectivity and chargeability. At least two types are encapsulated, and an electric field is applied to the display medium from a counter electrode formed by intersecting line electrodes provided on two substrates, thereby moving the at least two types of display medium to An information display panel for displaying information,
In the relationship between the thickness of each line-shaped electrode and the optical reflectance and the average particle diameter of the particles having charging properties included in each particle group as the at least two types of display media, the at least two types of display media are used. An information display panel, wherein the thickness of each line-shaped electrode is made smaller than the smallest average particle diameter among the average particle diameters of particles having optical reflectivity and chargeability included in each particle group.   3. The information display panel according to claim 1, wherein the thickness of each line electrode is larger than 5 nm.   The information display panel according to any one of claims 1 to 3, wherein the arrangement of the cells formed by the partition walls corresponds to the arrangement of the line-shaped electrodes.

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