JP2007140110A - Panel for information display and information display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a panel for information display with which three or more kinds of colors are distinguished among one another and displayed. <P>SOLUTION: The panel for information display is constructed in such a way that: kinds of colors of display mediums 3 to be sealed in a plurality of cells 10 formed between substrates 1, 2 are made to be three or more; at least two kinds of display mediums 3A, 3B with mutually different colors have polarities identical to each other and further have charge characteristics whose electric field threshold values are mutually different; and the panel displays the information by selectively transferring only the display medium having the electric field threshold value lower than intensity of an electric field applied from the outside. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is for information display in which a display medium is sealed between two opposing substrates at least one of which is transparent, and an electric field is applied to the display medium to move the display medium to display information such as an image. The present invention relates to a panel and an information display device using the panel.

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

  Compared to LCDs, these conventional technologies have advantages such as a wide viewing angle close to that of ordinary printed materials, low power consumption, and a memory function. It is considered as a technology that can be used for mobile phones, and is expected to expand to information display for mobile terminals, electronic paper, and the like. Particularly recently, an electrophoretic method in which a dispersion liquid composed of dispersed particles and a colored solution is encapsulated and disposed between opposing substrates has been proposed and is expected.

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

  On the other hand, a method in which conductive particles and a charge transport layer are incorporated into a part of a substrate without using a solution is proposed instead of an electrophoresis method using behavior in a solution (see, for example, Non-Patent Document 1). ). However, since the structure is complicated to arrange the charge transport layer and further the charge generation layer, and it is difficult to inject the charges into the conductive particles, it is difficult to rewrite the display. is there.

As one method for solving the various problems described above, at least one kind having at least one kind of particles composed of at least one kind of particles between two opposing substrates, at least one of which is transparent, has chargeability. An information display panel that displays information by moving the display medium by enclosing the above display medium and applying an electric field to the display medium is known.
趙 Kuniaki and three others, “New Toner Display Device (I)”, July 21, 1999, Annual Meeting of the Imaging Society of Japan (83 times in total) “Japan Hardcopy'99” Proceedings, p.249-252

  The information display panel having the above-described configuration conventionally has an electric field in which two types of display media having different colors are sealed between two substrates of cells constituting the panel, and one of the display media having different polarities is applied. Since the information is displayed by moving toward the substrate determined according to the orientation of the display and moving the other display medium toward the opposite substrate, two types of colors are displayed. Even if it can be done, it is not possible to distinguish and display three or more colors, limiting the quality and amount of information to be displayed, and improvements in this respect have been sought.

  The present invention has been made in view of such problems, and an object thereof is to provide an information display panel capable of distinguishing and displaying three or more colors and an information display device using the panel. And

<1> is a method in which a display medium is sealed in a plurality of cells formed between two opposing substrates, at least one of which is transparent, and an electric field is applied to the display medium from the outside of the substrate. In the information display panel that moves and displays information such as images,
The display medium encapsulated between the substrates has three or more types of colors, and at least two types of display media having different colors have the same polarity and charge characteristics that are different from each other in electric field threshold value. An information display panel configured to display the information by selectively moving only a display medium having an electric field threshold value lower than an applied electric field strength.

  <2> is an electric field that applies at least one of display media having different polarities and having one of different charge polarities in at least two of the display media having different colors enclosed in the cell in <1>. The information display according to claim 1, wherein the information is displayed by moving toward the substrate determined according to the orientation of the display and moving the other display medium toward the substrate on the opposite side. Panel.

  <3> is the information display panel according to claim 1 or 2, wherein the electric field threshold value is made different by changing the charge amount of the display medium in <1> or <2>.

  <4> is the information according to claim 3, wherein the charge amount of the display medium is varied by varying at least one of the amount and type of the charge control agent blended as the display medium material in <3>. This is a display panel.

  <5> is an information display panel according to any one of <1> to <4>, in which the display medium having the same polarity charging characteristics enclosed in the cell has two to three colors.

  <6> is information configured to apply an electric field to the display medium by touching the information display panel of any one of <1> to <5> and the display surface of the information display panel. It is a display device.

  <1> According to <1>, at least two types of display media having different colors are used in the display medium enclosed in the cell, and the charging characteristics are different from each other and have the same polarity and different electric field thresholds. As will be described in detail later, when an electric field lower than the higher one of the two electric field thresholds is added from the outside, and an electric field higher than this electric field threshold is added. Sometimes, the display color can be changed, and this can be used to express three or more display colors.

  According to <2>, at least two types of display media with different colors enclosed in a cell are configured to have charging characteristics of different polarities, so that the display color can also be changed by changing the direction of the electric field. More types of color display.

  According to <3>, since the electric field threshold value is made different by changing the charge amount of the display medium, a display medium having a predetermined electric field threshold value can be easily created.

  According to <4>, since at least one of the amount and type of the charge control agent to be blended as the display medium material is varied, the charge amount of the display medium can be easily varied.

  <5> According to <5>, there are two or three types of colors of the display medium having the same polarity charging characteristics enclosed in the cell. If the number of types exceeds three, the electric field thresholds of those display media are too close to each other, making it difficult to stably change the display color.

  According to <6>, since the information display panel described above and the display surface of the information display panel are touched, an electric field is applied to the display medium. Further, since the electric field forming means is a touch pen type, the display can be easily rewritten by a human operation.

  In the information display panel which is an object of the present invention, an electric field is applied to a display medium sealed in a plurality of cells formed 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 moving direction of the display medium changes due to the change of the electric field direction due to the potential switching, thereby displaying information such as images. 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 attracted by the Coulomb force between the particles, an electric mirror image force with the substrate, an intermolecular force, a liquid crosslinking force, gravity, and the like can be considered.

  An information display panel according to an embodiment of the present invention will be described with reference to the drawings. 1 to 3 are conceptual cross-sectional views showing a state in which unit cells constituting the information display panel of the first embodiment are displaying different colors, and the cell 10 is on the back side. A substrate 1, a display surface side transparent substrate 2, and a partition 4 provided between these substrates 1 and 2, for example, in a lattice shape, are formed of at least one kind of particles, and have color and charging characteristics. Are different from each other in three or more types of display media 3 (here, the first color display medium 3A composed of the first color display medium particles 3Aa and the second color display medium particles 3Ba). Second color display medium 3B and third color display medium 3C consisting of particle groups of third color display medium particles 3Ca). In the present invention, it is assumed that an electric field forming means for applying an electric field is not provided in the cell 10 and an electric field is applied from the outside using the electric field forming means.

  Here, in this specification, the “color of the display medium” is a characteristic that corresponds to the spectrum of optical reflectance on a one-to-one basis. Therefore, display media of different colors are different from each other. It means having different optical reflectance spectra. For example, even if the lightness is different, the colors are expressed as different. In addition, as examples of the first color, the second color, and the third color, for example, white, red, and black can be associated in this order.

  In addition, the charging characteristic is a characteristic that combines a charging polarity expressed by positive and negative and an electric field threshold value, and the electric field threshold value of the display medium is a minimum necessary for moving particles of the display medium. Defined as field strength. Since this electric field threshold depends on the electric charge of the particles of the display medium, it is preferable to provide the predetermined electric field threshold by adjusting the electric charge of the display medium by controlling the electric charge of the particles. Strictly speaking, this electric field threshold value depends on the direction of the electric field to be applied, but its dependency is small. Therefore, in the following description, it will be treated as not depending on the direction of the electric field.

  At least two of the three or more types of display media 3 having different colors have the same charge polarity and different electric field thresholds. Further, at least two of the three or more types of display media have a charge polarity. For example, as shown in Table 1, Table 1 shows that, for example, the first color is positively charged and the electric field threshold value is a1.

In Table 1, the electric field threshold has the relationship of the formula (1), and the first color display medium has a lower electric field threshold than the second color display medium. The size of b1 can be determined independently of a1 and a2.

a1 <a2 (1)

  Table 2 shows the direction and electric field of an electric field to be added to display three kinds of colors using such display media 3A, 3B, and 3C, and the figure numbers indicating the state of the display medium at this time. Indicated. In Table 2, for example, the display color B, that is, a mixed color of the first color and the second color, is displayed by applying an electric field having a direction of D1 and an intensity of x2, as shown in FIG. It means that you can.

Here, in the figure and Table 2, the electric field direction D1 is the electric field direction for moving the positively charged display medium (in this example, the first color and the second color) to the display surface side transparent substrate 1. The electric field direction D2 represents the opposite direction to D1. In addition, the electric field strength has a relationship of formulas (2) and (3).

a1 <x1 <a2 <x2 (2)
b1 <y1 (3)

  Further, when changing the above display color, for example, when changing from the display color B to the display color A, as shown in FIG. It is preferable that the display is erased once separated from the substrate 1 and then appears in a new display color. A method for erasing can be realized by applying an attenuated alternating electric field as shown in FIG.

  As a method of applying an electric field to the cell 10 as described above, a method of forming an electrostatic latent image used in electrophotographic applications on a panel substrate, a method of forming charges on the panel substrate by ion flow, Examples include a method in which a panel is mounted between the external electrodes and an electric field is formed by the external electrodes, and a method using the touch pen type electronic input device 8 as shown in FIGS.

Here, by combining the information display panel as described above and the touch pen type voltage input device 8 functioning as an electric field forming means for applying an electric field to the display medium, the display can be easily rewritten by a human operation. An information display device can be configured.
The usage is illustrated below. The first color, the second color, and the third color in the first embodiment are set in this order as white, red, and black, respectively, and the information display is performed on the information panel of the first embodiment by, for example, charge irradiation by ion flow. An electric field of a pattern desired to be displayed on the panel is formed, and a black and white pattern in which black characters are drawn on a white background, for example, by a white display cell and a black display cell is displayed. According to Table 2, such a pattern is formed by applying an electric field with intensity x1 and direction D1 to the white display cell, and applying an electric field with intensity y1 and direction D2 to the black display cell. can do.
Subsequently, a voltage corresponding to an electric field having an intensity of x2 and a direction of D1 is applied to the touch pen type voltage input device 8, and a white display cell forming a white background with the touch pen of the touch pen type voltage input device 8 is displayed. By touching the surface, an electric field of intensity x2 and direction D1 is applied to the white display cell, and the red display medium 3B is moved to the display surface side as shown in FIG. Can be displayed in a pink color, which is a mixed color of red and red. For example, a pinned underline can be drawn on a white background portion under a black character.

  You can also use it as follows. The touch pen type voltage input device 8 is configured so that the input voltage can be changed. For example, as shown in FIG. 1, first, a small electric field is input to form a small electric field to display a low electric field threshold value. The medium 3A is moved to the surface of the touched substrate 1, and then, as shown in FIG. 2, a large voltage is input to form a large electric field, and the display medium 3B having a high electric field threshold is also applied to the surface of the touched substrate 1. Move. Even when other electric field forming means is used, multicolor display can be performed by the same procedure.

  6 to 10 are conceptual cross-sectional views showing a state in which unit cells constituting the information display panel of the second embodiment are displaying different colors, and the cell 20 is a back side substrate. 1, a display surface side transparent substrate 2, and a partition 4 provided between these substrates 1 and 2, for example, in a lattice shape, and is composed of at least one kind of particles and has color and charging characteristics. All of them are composed of five different types of display media 3 (here, a first color display medium 3A composed of particles of the first color display medium particles 3Aa and a particle group of second color display medium particles 3Ba). A second color display medium 3B, a third color display medium 3C composed of particle groups of third color display medium particles 3Ca, a fourth color display medium 3D composed of particle groups of fourth color display medium particles 3Da, From the particle group of particles 3Ea for five colors of display media That consists fifth color display media 3E) by sealing.

  Here, as an example of the first to fifth colors, for example, white, red, black, yellow, and green can be associated in this order.

Table 3 shows the charging characteristics of the display medium in the information display panel of the second embodiment in the same manner as in Table 1. In Table 3, the electric field threshold value of these display media is expressed by Equation (4). And the magnitude relationship in the set of a1, a2, and a3 and the magnitude relationship in the set of b1, b2 are indispensable requirements in this form, but b1, b2 The size of the set and the set of a1, a2, and a3 can be determined independently of each other.

a1 <a2 <a3 (4)
b1 <b2 (5)

  Using such display media 3A, 3B, 3C, 3D, and 3E, the direction and electric field of an electric field to be added to display five types of colors, and a diagram number indicating the state of the display medium at this time are shown. Table 4 shows the same format as Table 2.

Here, the direction D1 of the electric field in Table 4 is an electric field for moving a positively charged display medium (in this example, the first color, the second color, and the fourth color) to the display surface side transparent substrate 1. The electric field direction D2 represents the opposite direction to D1. Further, the electric field strength has a relationship of the formulas (6) and (7).

a1 <x1 <a2 <x2 <a3 <x3 (6)
b1 <y1 <b2 <y2 (7)

  When the display color is changed, as described above, all display media are separated from the substrate 1 and temporarily displayed as shown in FIG. 11 so that the history of the previous display color does not remain. After erasing, it is preferable to appear in a new display color, and a method for erasing can be realized by applying an attenuated alternating electric field as shown in FIG.

  Further, as illustrated by arranging two cells 20 side by side in FIG. 11, a plurality of cells 20 are defined between the substrates 1 and 2 by partition walls. As described above, the method of applying an electric field to these cells 20 includes a method of forming an electrostatic latent image used in electrophotographic applications on the panel substrate, and a charge on the panel substrate by ion flow. , A method of forming a panel between external electrodes and forming an electric field by the external electrodes, a method of using the touch pen type electronic input device 8 described in detail above, and the like.

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

  As for the substrate, at least one substrate is the transparent substrate 2 from which the color of the display medium 3 can be confirmed from the outside of the panel, and a material having high visible light transmittance and good heat resistance is preferable. The substrate 1 may be transparent or opaque. Examples of substrate materials include polymer sheets such as polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyethylene, polycarbonate, polyimide, and acrylic, flexible materials such as metal sheets, and glass and quartz. An inorganic sheet having no flexibility is mentioned. 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.

The shape of the partition walls 4 provided on the substrate is optimally set depending on the type of display medium involved in the display and is not limited in general. However, the partition wall width is 2 to 100 μm, preferably 3 to 50 μm. The thickness 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. 12, the cells formed by the partition walls made up of these ribs are exemplified by a square shape, a triangular shape, a line shape, a circular shape, and a hexagonal shape as viewed from the substrate plane direction. And 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 opposing substrates, at least one of which is transparent. Yes, such a powder fluid can be easily and stably moved by a Coulomb force under a low electric field.
As described above, for example, the powder fluid used as a display medium in the present invention is a substance in an intermediate state between fluid and particles that exhibits fluidity by itself without borrowing the force of gas or liquid. It is. 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.

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

  As a result of intensive studies, the present inventors have been able to evaluate the range of proper charging characteristics of display medium particles by measuring the charge amount of the particles used in the display medium using the same carrier particles in the blow-off method. I found.

Furthermore, when applying a display medium such as a particle group or a powder fluid composed of particles for a display medium 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.
For example, in FIG. 1, the void portion is a so-called display in which the occupied portion of the display medium 3, the occupied portion of the partition wall 4, and the seal portion of the information display panel are excluded from the portion sandwiched between the opposing substrates 1 and 2. It shall refer to the gas part in contact with the medium.
The gas in the gap is not limited as long as it is in the humidity region described above, but dry air, dry nitrogen, dry argon, dry helium, dry carbon dioxide, dry methane, and the like are preferable. This gas needs to be sealed in the information display panel so that the humidity is maintained. For example, the display medium is mounted and the information display panel is assembled 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 according to the present invention includes display units for 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, calculators, and home appliances. It is suitably used for display parts for automobile supplies, card display parts such as point cards and IC cards, electronic advertisements, electronic POPs, electronic price tags, electronic shelf labels, electronic musical scores, and display parts for RF-ID devices.

It is a conceptual sectional view showing the cell of the information display panel of a first embodiment concerning the present invention in the state where display color A was displayed. It is a conceptual sectional view showing the cell of the information display panel of the first embodiment in a state where display color B is displayed. It is a conceptual sectional view showing the cell of the information display panel of the first embodiment in a state where display color C is displayed. It is a conceptual sectional view showing the cell of the information display panel of the first embodiment in a state where all display colors are erased. It is a graph which shows the time change of the attenuation alternating electric field for erasing a display. It is a conceptual sectional view showing the cell of the information display panel of a second embodiment in the state where display color A is displayed. It is a conceptual sectional view showing the cell of the information display panel of a second embodiment in the state where display color B is displayed. It is a conceptual sectional view showing the cell of the information display panel of a second embodiment in the state where display color C is displayed. It is a conceptual sectional view showing the cell of the information display panel of a second embodiment in the state where display color D is displayed. It is a conceptual sectional view showing the cell of the information display panel of a second embodiment in the state where display color E is displayed. It is a conceptual sectional view showing a cell of an information display panel of a second embodiment in a state where all display colors are erased. It is a figure which shows an example of the shape of the partition in the information display panel of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Display surface side transparent substrate 2 Back surface side substrate 3 Display medium (particle group, powder fluid)
3A First color display medium 3Aa First color display medium particle 3B Second color display medium 3Ba Second color display medium particle 3C Third color display medium 3Ca Third color display medium particle 3D Fourth color display medium 3Da First Particles for four-color display medium 3E Fifth color display medium 3Ea Particles for fifth color display medium 4 Bulkhead 8 Touch pen type voltage input device 10, 20 Information display panel cell

Claims (6)

A display medium is sealed in a plurality of cells formed between two opposing substrates, at least one of which is transparent, and an electric field is applied to the display medium from the outside of the substrate, thereby moving the display medium to display an image, etc. In the information display panel that displays the information of
The display medium encapsulated between the substrates has three or more types of colors, and at least two types of display media having different colors have the same polarity and charge characteristics that are different from each other in electric field threshold value. An information display panel configured to display the information by selectively moving only a display medium having an electric field threshold value lower than an applied electric field strength.   At least two types of display media of different colors enclosed in the cell have charging characteristics of different polarities, and one of the display media having different charging polarities is used as a substrate determined according to the direction of the applied electric field. The information display panel according to claim 1, wherein the information display panel is configured to display the information by moving the other display medium toward the opposite substrate.   The information display panel according to claim 1, wherein the electric field threshold value is varied by varying a charge amount of the display medium.   4. The information display panel according to claim 3, wherein the charge amount of the display medium is varied by varying at least one of the amount and type of the charge control agent blended as the material of the display medium.   The information display panel according to claim 1, wherein the display medium having the same polarity charging characteristics enclosed in the cell has two to three colors. 6. The information display panel according to claim 1, and a touch pen type electric field forming unit configured to apply an electric field to the display medium by touching a display surface of the information display panel. An information display device comprising:

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