WO2007080960A1

WO2007080960A1 - Information display panel

Info

Publication number: WO2007080960A1
Application number: PCT/JP2007/050314
Authority: WO
Inventors: Hirotaka Yamazaki; Kazuya Murata; Gaku Yakushiji
Original assignee: Bridgestone Corporation
Priority date: 2006-01-16
Filing date: 2007-01-12
Publication date: 2007-07-19
Also published as: JPWO2007080960A1

Abstract

This invention provides an information display panel having excellent display quality. The information display panel comprises a display medium comprising display medium particles of two colors of black and white that ensure desired whiteness and blackness and a proper level of chargeability by using white particles (3Wa) for a white display medium using a proper amount of titanium oxide, in combination with black particles (3Ba) for a black display medium using a proper amount of carbon black. The information display panel has such a structure that display media of respective two colors of black and white different from each other in charging polarity are sealed in an in-gas space between two opposed substrates (1) (2) at least one of which is transparent. The display media of two colors of white and black different from each other in charging polarity comprise a white display medium (3W) comprising white particles (3Wa) containing titanium oxide and a negative chargeability imparting charge control agent, and a black display medium (3B) comprising black particles (3Ba) containing carbon black and a positive chargeability-imparting charge control agent. The information display panel may be used in electronic paper applications.

Description

Specification

Information display panel

[0001] The present invention provides a black and white two-color display medium having at least one kind of particle force between gas cavities between two opposing substrates, at least one of which is transparent, and having different charging polarities. The present invention relates to an information display panel that displays information by moving a display medium by an electric field that is sealed and generated in a substrate.

Background art

[0002] In recent years, as an information display panel used for electronic paper applications, at least one of two or more transparent particles having two or more types of particle force between two opposing substrates transparent to each other is displayed. An information display panel has been proposed in which a medium is enclosed and the display medium is moved by an electric field generated in the substrate to display information (see, for example, a pamphlet of WO / 2003/050606). In such an electronic paper application, white and black are often selected as a combination of two colors because of demands such as not being tired and excellent in visibility (for example, Japanese Patent Laid-Open No. 2004-2006). No. 287061).

[0003] When obtaining white particles for white display media, in many cases, titanium oxide is used as a pigment, and when obtaining black particles for black display media, carbon is often used as a colorant. Black was used. However, the particles for display media need to have not only whiteness and blackness but also appropriate chargeability to be driven by the force of the electric field generated in the substrate. Appropriate chargeability means that white particles for white display media and black particles for black display media have oppositely charged polarities, and the amount of charge can be easily driven by the force of an electric field. Means that.

[0004] However, titanium oxide has the property of making the particles containing it negatively charged. On the other hand, carbon black is electrically conductive, so it is composed of black and white display medium particles. In a display medium, a display medium having sufficient whiteness, sufficient blackness, and appropriate chargeability could not be obtained.

Disclosure of the invention [0005] The present invention uses a combination of white particles for a white display medium using an appropriate amount of titanium oxide and black particles for a black display medium using an appropriate amount of carbon black. It is an object to provide an information display panel excellent in display quality, which is composed of a display medium composed of particles for two colors of black and white, which secures blackness, blackness and appropriate chargeability.

[0006] The first invention of the information display panel of the present invention encloses a black and white two-color display medium having different charging polarities between two opposing air gaps in which at least one of the substrates is transparent. In an information display panel having a structure, a white and black two-color display medium having different charging polarities, a white display medium containing at least white particles containing at least titanium oxide and a charge control agent imparting negative chargeability, and at least carbon A black display medium including at least black particles containing black and a charge control agent imparting a positive chargeability, and a force is constituted.

[0007] In the second invention of the information display panel of the present invention, a black and white two-color display medium having different charging polarities is encapsulated between two opposing air gaps in which at least one substrate is transparent. An information display panel with a structure, in which a partition wall is provided between two opposing substrates to maintain a gap between the substrates and partition the space between the substrates continuously or intermittently. In an information display panel with a structure in which a black and white two-color display medium is enclosed in a cell consisting of a specified air space, a unit pixel is composed of three cells, and at least the substrate side, which is the display surface side, is a transparent three primary color White particles containing three color filters with colors and two or more black and white display media having different charge polarities, and containing at least titanium oxide and a charge control agent imparting negative chargeability Including at least white A display medium, and is characterized in that it consisted of at least including black color display media black particles containing a charge control agent which imparts at least carbon black and the positive charging property.

[0008] As a suitable example of the information display panel of the present invention, the titanium oxide contained in the white particles constituting the white display medium having a negatively charged polarity is set to 10 parts by weight or more, and the positively charged polarity. The carbon black contained in the black particles constituting the black display medium may be 0.1 to LO parts by weight.

[0009] According to the information display panel of the present invention, the titanium oxide content is preferably 10 wt%. White particles constituting a white display medium having a sufficient white color and an appropriate negative charge polarity obtained by setting the amount to be at least parts, and the carbon black content is preferably in the range of 0.1 to 10 parts by weight. The two-color display medium having a different charge polarity is composed of sufficiently black and black particles constituting the black display medium having an appropriate positive charge polarity. It is an information display panel with excellent display quality, which is composed of a black and white display medium that guarantees a high degree of blackness and proper chargeability. Brief Description of Drawings

FIG. 1 (a) and (b) are diagrams showing an example of an information display panel of the present invention.

FIG. 2 (a) and (b) are views showing another example of the information display panel of the present invention.

FIG. 3 is a view showing still another example of the information display panel of the present invention.

FIG. 4 is a view showing still another example of the information display panel of the present invention.

FIG. 5 is a diagram showing an example of the shape of a partition wall in the information display panel of the present invention.

FIG. 6 is a diagram showing a procedure for measuring the surface potential of the colored particles constituting the particles for display medium used in the information display panel of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

First, the basic configuration of the information display panel of the present invention will be described. In the information display panel that is the subject of the present invention, an electric field is applied to a display medium sealed between two opposing substrates. Along with the applied electric field direction, the charged display medium is attracted by the electric field force or Coulomb force, etc., and the display medium changes the moving direction due to the change in electric field direction by switching the potential, 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 the stability when the display is repeatedly rewritten or when the display information is continuously displayed. Here, the force exerted on the particles composing the display medium is not only the force attracted by the Coulomb force between the particles, but also the electric mirror image force between the electrode and the substrate, intermolecular force, liquid bridging force, gravity, etc. Can be considered.

[0012] An example of an information display panel that is an object of the present invention will be described with reference to Figs. L (a) and (b) to Figs. 2 (a) and (b).

[0013] In the examples shown in Figs. 1 (a) and (b), at least one kind of particle force is included in the optical reflection. At least two or more types of display media 3 having different rates and charging characteristics (here, a white display medium 3W having a particle group power of 3Wa and a black display medium 3B having a particle group of 3Ba and a black display medium 3B) ) Is moved vertically to the substrate 2 in accordance with the electric field applied from the outside of the substrate 2, and the black display medium 3B is visually recognized by the observer to display black, or the white display medium 3W is observed. A white display is given to the user. In the example shown in FIG. 1 (b), in addition to the example shown in FIG. 1 (a), a partition 4 is provided between the substrates 1 and 2, for example, in the form of a lattice to form a cell. In Fig. 1 (b), the front partition is omitted. Conductive members can be provided in layers on the inner sides (sides in contact with the display medium) of the two substrates. As the conductive member, a conductive metal oxide such as tin-doped indium oxide (ITO), zinc-doped indium oxide (IZO), indium oxide or tin-doped antimony oxide (ATO) is preferably used.

[0014] In the example shown in Figs. 2 (a) and (b), at least two or more display media 3 (here, white display media) having different optical reflectivity and charging characteristics that are also configured with at least one particle force. White display medium 3W, which is a particle group force of 3Wa, and black display medium 3B, which is a particle group of 3Ba, which is a particle group of 3Ba), and an electrode 5 provided on substrate 1 and an electrode 6 provided on substrate 2 Depending on the electric field generated by applying a voltage between them, the substrate 2 is moved vertically to make the black display medium 3B visible to the observer to display black, or the white display medium 3W to the observer The white display is made visible. In the example shown in FIG. 2 (b), a partition 4 is provided between the substrate 2 and a lattice, for example, to form a cell. In Fig. 2 (b), the front partition is omitted. The electrodes arranged opposite to each other can be individual electrodes or line electrodes orthogonal to each other. Electrodes that are preferably provided on the inner side of each of the two substrates (the side in contact with the display medium) include tin-doped indium oxide (ITO), zinc-doped indium oxide (IZO), and indium oxide tin. A conductive metal oxide such as doped acid antimony (ATO) is preferably used.

[0015] The above description is the same when the white display medium 3W made of particle groups is replaced with a white display medium made of powdered fluid, and the black display medium 3B also made of particle group forces is replaced with a black display medium also made of powdered fluid force. It can be applied to. The powder fluid will be described later. [0016] A feature of the present invention is that the information display panel having the above-described configuration includes a black and white two-color display medium having different charging polarities, and at least an acid titanium and a charge control agent imparting negative chargeability. A white display medium containing at least white particles, and a black display medium containing at least black particles containing at least carbon black and a charge control agent imparting positive chargeability.

Here, the white particles constituting the white display medium contain 10 parts by weight or more, preferably 20 parts by weight or more of titanium oxide, and the black particles constituting the black display medium include It is preferable that the carbon black is contained in the range of 0.1 to: LO parts by weight.

[0018] Also, it is desirable that the amount of titanium oxide contained in the white particles constituting the white display medium is as large as possible. However, when white particles are obtained by a polymerization method, the content exceeds 100 parts by weight. It is difficult to produce a large amount, and it is produced in the range of 10 to: LOO parts by weight.

[0019] When the white particles constituting the white display medium are obtained by the kneading Z pulverization Z classification method, a large amount of titanium oxide can be contained unlike the polymerization method. Those having a content exceeding 100 parts by weight can be prepared, and are prepared in the range of 10 to 500 parts by weight, preferably 50 to 300 parts by weight, and more preferably 100 to 200 parts by weight. Here, even when the white particles constituting the white display medium are obtained by the kneading Z pulverization Z classification method, a sufficient white color cannot be obtained if the amount of titanium oxide is less than 10 parts by weight. In addition, when the amount exceeds 500 parts by weight, there are problems that the particle strength is lowered and breaks easily, and that kneading is difficult.

[0020] If the amount of carbon black contained in the black particles constituting the black display medium is 0.1 parts by weight or more, sufficient black can be obtained, but if it is less than 0.1 parts by weight, sufficient black can be obtained. Absent. In addition, if the amount exceeds 10 parts by weight, the conductivity increases and proper positive chargeability cannot be obtained and the particles do not function as display medium particles. Therefore, the black particles have a carbon content in the range of 0.1 to LO parts by weight. Produced.

FIGS. 3 to 4 are diagrams for explaining other examples of the information display panel of the present invention. In the example shown in FIGS. 3 to 4, the same members as those shown in FIGS. 1 (a) and 1 (b) and FIGS. 2 (a) and 2 (b) are denoted by the same reference numerals, and the description thereof is omitted. . The examples shown in Figs. In the transparent substrate 2 on the display surface side, three primary color filters 12R (red), 12G (corresponding to the cell 11 consisting of the gas space partitioned by the partition 4 are shown. Green) and 12B (blue purple) are provided separately, and one pixel is composed of three cells 11 each provided with color filters 12R, 12G, and 12B, enabling color display. Among the examples shown in FIGS. 3 to 4, the example shown in FIG. 3 shows an example in which the color filters 12R, 12G, and 12B are provided on the outer surface of the transparent substrate 2. The example shown in FIG. 4 shows an example in which the color filters 12R, 12G, and 12B are provided in contact with the respective electrodes 6. In any example, the color display in the present invention can be suitably performed.

[0022] Each member constituting the information display panel of the present invention will be described below.

[0023] Regarding the substrate, at least one of the substrates is a transparent substrate capable of confirming the color of the display medium as well as the information display panel outer force, and a material having high visible light transmittance and good heat resistance is preferable. The other substrate can 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, glass, Non-flexible inorganic sheets such as quartz can be mentioned. The thickness of the substrate is 2 to 5000 111 centimeters, and 5 to 2000 / ζ πι force S is preferable. If it is too thin, the strength and uniformity of the distance between the substrates will be maintained, from 5000 / zm. Thickness V is inconvenient for thin information display panels.

[0024] As the material for forming the electrode and the conductive members 5 and 6 when the electrode or conductive member is provided on the substrate of the information display panel, metals such as aluminum, silver, nickel, copper and gold, tin-doped indium oxide ( ITO), zinc-doped indium oxide (IZO), tin-doped antimony oxide (ATo), indium oxide, conductive tin oxide, conductive metal oxides such as conductive zinc oxide, polyline, polypyrrole, polythiophene, etc. Conductive polymers are exemplified and appropriately selected and used. As a method for forming an electrode or a conductive member, the above-described materials are formed into a thin film by sputtering, vacuum deposition, CVD (chemical vapor deposition), coating, or the like, or a conductive agent is used as a solvent or a synthetic resin binder. The method of mixing and applying to is used. In many cases, the electrodes and conductive members provided on the display surface side substrate need to be transparent, but the electrodes and conductive members provided on the back side substrate need to be transparent. V, even in case of misalignment The above-mentioned material that can form a turn and is electrically conductive can be suitably used. The thickness of the electrode and the conductive member is 3 to 1 nm, preferably 5 to 400 nm, as long as the conductivity can be secured and the light transmittance is not affected. The material and thickness of the electrode and conductive member 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 be transparent. In this case, the external voltage input may be superimposed with direct current or alternating current.

The electrode and the conductive member are preferably provided on the inner side (the side in contact with the display medium) of the substrate.

[0025] The shape of the partition walls 4 provided on the substrate as necessary is appropriately set according to the type of display medium involved in the display, and is not limited in general, but the width of the partition walls is 2 to: LOO μm, Preferably, the height of the partition wall is adjusted to 3 to 50 μm, and the height of the partition wall is adjusted to 10 to 500 μm, preferably 10 to 200 μm. In forming the partition walls, a double rib method in which ribs are formed on both opposing substrates 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.

[0026] The cells formed by the partition walls having these rib forces are exemplified by a square shape, a triangular shape, a line shape, a circular shape, and a hexagonal shape as viewed from the substrate plane direction as shown in FIG. Examples of the child shape include a honeycomb shape and a mesh shape. Display side force It is better to make the part corresponding to the visible section of the partition wall (the area of the cell frame) as small as possible. Here, examples of the method for forming the partition include a mold transfer method, a screen printing method, a sand blast method, a photolithography method, and an additive method. Among these, a photolithographic method using a resist film or a mold transfer method is preferably used.

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

[0028] 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, a liquid crystal is defined as an intermediate phase between a liquid and a solid, and has fluidity that is a characteristic of a liquid and anisotropy (optical properties) that is a characteristic of a solid (Heibonsha: Large Encyclopedia). ). On the other hand, the definition of a particle is an object with a finite mass even if it is negligible. (Maruzen: Physics Encyclopedia). Here, even in the case of particles, there are special states of gas-solid fluidized bed and liquid-solid fluidized bodies. 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. When it balances with gravity, it is called a gas-solid fluidized bed that is in a state where it can easily flow like a fluid, and a state fluidized by the same fluid is called a liquid-solid fluid. (Heibonsha: Encyclopedia). As described above, the gas-solid fluidized bed body and the liquid-solid fluid body are in a state using a flow of gas or liquid. In the present invention, it has been found that a substance in a state of fluidity can be created 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 an intermediate state having both the characteristics of particles and liquid, as in the definition of liquid crystal (intermediate phase between liquid and solid), and has the characteristics of the particles described above. It is a substance that shows a unique state with high fluidity that is extremely difficult to be affected by gravity. Such a substance can be obtained in an aerosol state, that is, a dispersion system in which a solid or liquid substance is stably suspended as a dispersoid in a gas. The information display panel of the present invention can obtain a solid substance as a dispersoid. It is what.

[0030] The information display panel of the present invention has high fluidity in an aerosol state in which solid particles are stably suspended as a dispersoid, for example, in a gas as a display medium between opposing substrates, at least one of which is transparent. This kind of powder fluid is so fluid that the angle of repose, which is an index indicating the fluidity of the powder, cannot be measured. Therefore, it can be easily and stably moved.

As described above, for example, the powder fluid used as the display medium in the present invention is an intermediate state of both fluid and particle characteristics that exhibit fluidity by themselves without borrowing the force of gas or liquid. It is a substance. This powder fluid can be in an aerosol state in particular, and the information display panel of the present invention is used in a state where a solid substance floats relatively stably as a dispersoid in the gas.

Next, particles for display medium constituting the display medium in the information display panel of the present invention

(Hereinafter also referred to as particles) will be described. The colored particles for display medium may be composed of colored particles as they are to form a display medium, or may be combined with other particles to form a display medium, or may be adjusted and configured to become a powder fluid to form a display medium. Used. The display medium particles of the present invention may be white particles having a negative charge polarity and black particles having a positive charge polarity. In particular, the display medium is preferably configured as particles having a spherical shape and a small specific gravity.

[0032] A method for charging the particles for display medium positively or negatively is not particularly limited, and a charging method such as a corona discharge method, an electrode injection method, a friction method or the like is used. In the charge amount of black and white two-color display medium particles used in the information display panel of the present invention, the charge amount measured by the blow-off method using the same carrier is 5 to 150 CZg in absolute value. The difference is preferably 5 to 150 C / g in absolute value. Absolute value of charge amount and absolute value force of charge difference S If the value is smaller than this range, the response speed to electric field changes will be slow, and the memory performance will be low. If the absolute value of the charge amount and the absolute value of the charge amount difference are larger than this range, the mirror image force on the electrode and the substrate is too strong, and the memory property is good, but the reversibility of the display medium when the electric field direction is reversed Deteriorate.

[0033] As a result of intensive investigations, the present inventors measured the charge amount of particles used for a display medium by using the same carrier particles in the blow-off method, and thus the range of the appropriate charging characteristic value of the particles for display medium. The amount of charge was measured by the following: o

[0034] <Blow-off measurement principle and measurement method>

In the blow-off method, a mixture of display medium particles and carrier particles is placed in a cylindrical container with nets at both ends, and high-pressure gas is blown at one end to separate display medium particles and carrier particles. Opening force Blow off only the particles for the display medium. At this time, the charge amount equivalent to the charge amount of the display medium particles taken away from the container remains in the carrier particles. All the electric flux due to this charge is collected by the Faraday cage, and the capacitor is charged by this amount. Therefore, by measuring the potential across the capacitor, the charge quantity Q of the particles for the display medium is

Q = CV (C: Capacitor capacity, V: Voltage across the capacitor)

As required.

[0035] TB-200 manufactured by Toshiba Chemical Co. was used as a blow-off charge measuring device. In the present invention, the carrier carrier particles are used to measure the charge amount of the particles for the display medium to be measured. When two types of display media, a display medium composed of positively charged particles and a display medium composed of negatively charged particles, are used in combination on the information display panel, the display that constitutes each display medium Use the same type of carrier particles when measuring the charge of the media particles. Specifically, the charge amount (μ C / g) of the particles was measured using DFC100 wrinkle (Mn-Mg-containing ferrite system) manufactured by Dowa Iron Powder Co., Ltd. as carrier particles.

[0036] Since the particles for display medium need to retain the charged charge, the volume resistivity is 1

X ¹⁰ 10 Ω 'cm or more insulating particles preferably tool particularly volume resistivity 1 X 10 ¹² Ω -cm or more insulating particles are preferred. Further, particles with slow charge decay evaluated by the method described below are more preferable.

[0037] That is, a display medium particle to be measured is arranged on the surface of a roll-shaped measurement jig, and a voltage of 8 KV is applied to a corona discharger arranged at a distance of 1 mm from the arranged display medium particle surface. Is applied to generate a corona discharge to charge the particle surface for display medium, and the change in the surface potential is measured and judged. In this case, it is important to select and prepare the display medium particle constituent material so that the maximum value of the surface potential after 0.3 seconds is larger than 300V, preferably larger than 400V.

[0038] The surface potential can be measured, for example, with the apparatus shown in FIG. 6 (CRT2000 manufactured by QEA). In the case of this apparatus, the both ends of the shaft of the roll-shaped measuring jig with the display medium particles to be measured arranged on the surface are held by the chuck 21, and a small scorotron discharger 22 and a surface potential meter 23 The measurement unit is placed in a roll shape with the measurement unit placed at a predetermined distance from the surface of the particles for the display medium to be measured with an interval of lmm. A method of measuring the surface potential of the display medium particles disposed on the surface of the measurement jig while applying surface charge by moving the particles to the other end at a constant speed is suitably employed. The measurement environment shall be a temperature of 25 ± 3 ° C and a humidity of 55 ± 5RH%.

[0039] The display medium particles may be composed of any material as long as the whiteness, blackness, charging performance, and the like are satisfied. For example, it can be formed from a resin, a charge control agent, a colorant, an inorganic additive and the like. As particles for display media, the glass transition of the resin constituting the particles. It is preferable to use one having a transition temperature Tg of 60 ° C or higher. The particles for white display medium contain, in addition to the main component resin, titanium oxide, a charge control agent imparting negative chargeability, another charge control agent, another colorant, an inorganic additive, and the like. I can do it. Particles for black display media contain carbon black, a charge control agent that imparts positive chargeability to the main resin, and other charge control agents, other colorants, inorganic additives, etc. be able to. Examples of the resin, charge control agent, colorant, and other additives are given below.

[0040] Examples of the resin include urethane resin, urea resin, acrylic resin, polyester resin, acrylic urethane resin, acrylic urethane silicone resin, acrylic urethane fluorine resin, acrylic fluorine resin, Silicone resin, acrylic silicone resin, epoxy resin, polystyrene resin, styrene acrylic resin, polyolefin resin, petital resin, vinylidene chloride resin, melamine resin, phenol resin, fluorine resin, polycarbonate resin Examples thereof include fat, polysulfone resin, polyether resin, polyamide resin, and the like, and two or more kinds can be mixed. In particular, from the viewpoint of controlling the adhesion to the substrate, acrylic urethane resin, acrylic silicone resin, acrylic fluorine resin, acrylic urethane silicone resin, acrylic urethane fluorine resin, fluorine resin, silicone resin Is preferred.

[0041] Further, styrene derivatives such as styrene, a-methylol styrene, p-chlorostyrene, chloromethylstyrene; chlor chloride; butyl esters such as butyl acetate and butyl propionate; unsaturated-tolyls such as acrylonitrile; Methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, ethylene glycol (meth) acrylate, triflu It is obtained by polymerizing polymerizable monomers such as (meth) acrylate derivatives such as oloethyl (meth) acrylate, pentafluoropropyl (meth) acrylate and cyclohexyl (meth) acrylate. Examples include fats. These polymerizable monomers may be used alone or in combination of two or more.

[0042] Further, when synthesizing the above-mentioned rosin, a crosslinkable monomer may be added, for example, in order to improve the properties of the display medium particles. Crosslinkable monomers include divinylbenzene, dibibiphenyl, dibinaphthalene, polyethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meta ) Atalylate, trimethylolpropane tri (meth) atalylate, tetramethylol methanetri (meth) a Thallate, tetramethylolpropane tetra (meth) acrylate, diaryl phthalate and its isomers, dibutyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, diaryl phthalate, etc. Crosslinkable monomers such as triallyl isocyanurate and derivatives thereof having two or more saturated bonds may be added. These crosslinkable monomers may be used alone or in combination of two or more.

[0043] In particular, it is preferable that a highly crosslinked resinous force obtained by polymerizing a monomer mixture containing the crosslinkable monomer is also obtained. When such a highly crosslinkable rosin is used, sufficient mechanical performance can be maintained even if it contains a large amount of titanium oxide as described above.

[0044] The charge control agent is not particularly limited, but examples of the negative charge control agent include oil-soluble salicylic acid metal complexes, metal-containing azo dyes, and metal-containing (including metal ions and metal atoms). Examples include dyes, quaternary ammonium salt compounds, force-rich allenic compounds, boron-containing compounds (benzyl acid boron complexes), and nitroimidazole derivatives, which affect the whiteness of particles for white display media. Those not used are preferably used. Examples of the positive charge control agent include Niguchicin dyes, triphenylmethane compounds, quaternary ammonium salt compounds, polyamine resins and imidazole derivatives. In addition, ultrafine silica, metal oxides such as ultrafine titanium oxide and ultrafine alumina, nitrogen-containing cyclic compounds such as pyridine and derivatives and salts thereof, various organic pigments, rosin containing fluorine, chlorine, nitrogen, etc. Can also be used as a charge control agent.

[0045] Carbon black is used as the black colorant. In addition, titanium oxide is used as the white colorant.

[0046] The display medium particles of the present invention preferably have a mean particle diameter d (0.5) force in the range of 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 particles becomes too large, which hinders movement as a display medium. Become.

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 set to less than 5, preferably less than 3.

Span = (d (0.9) -d (0.1)) /d(0.5) (However, d (0.5) is a numerical value expressed in m that the particle size is 50% larger than this and 50% smaller than this, and d (0.1) is a particle whose ratio is 10% or less. The diameter is expressed as / zm, and d (0.9) is the numerical value when the particle diameter is 90% or less, and is expressed as / zm.) By keeping Span within 5 or less, They are uniform in size and can be moved as a uniform display medium.

[0048] Further, regarding the correlation between the particles for display medium, 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 particles for display medium used is 50 or less. It is important to set it to 10 or less. Even if the particle size distribution Span is reduced, particles for display media with different charging characteristics move in opposite directions, so that the particle sizes are close to each other, and each particle can easily move in the opposite direction by the equivalent amount. This is the preferred range, and this is the range.

[0049] It should be noted that the particle size distribution and the particle size described above can be obtained from a laser diffraction Z scattering method or the like. When laser light is irradiated onto the display medium particles to be measured, a light intensity distribution pattern of diffracted Z-scattered light is generated spatially, and this light intensity pattern has a corresponding relationship with the 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, the particles are put into a nitrogen stream and the attached analysis software (software based on volume-based distribution using Mie theory) The diameter and particle size distribution can be measured.

[0050] Although the charge amount of the display medium particles naturally depends on the measurement conditions, the charge amount of the display medium particles in the information display panel is almost the initial charge amount, the contact with the partition, the contact with the substrate, It turned out that it depends on the charge decay with the elapsed time, and in particular the saturation value of the charging behavior of the particles for the display medium is the dominant factor.

[0051] Further, in a dry information display panel in which a display medium like the present invention is driven in a gas space, it is important to manage the gas in the gap surrounding the display medium between the substrates, and display stability is improved. Contribute to. Specifically, it is important that the relative humidity at 25 ° C is 60% RH or less, preferably 50% RH or less for the gas humidity in the voids.

These voids are the opposing substrate 1 and substrate 2 in FIGS. 1 (a) and 1 (b) to 2 (a) and 2 (b). From the portion sandwiched between the electrodes 5, 6 (when electrodes are provided inside the substrate), the occupied area of the display medium (particle group or powdered fluid) 3, the occupied area of the partition 4 (when the partition is provided), information Except for the seal part of the display panel, V, and the gas part in contact with the so-called display 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 suitable. This gas must be sealed in the information display panel so that the humidity is maintained. For example, filling of the display medium and assembly of the information display panel are performed in a predetermined humidity environment. It is important to use sealing materials and sealing methods that prevent external forces from entering the humidity.

[0052] The distance between the substrates in the information display panel 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 500 111, preferably 10 to 200 / ζ πι. The

The volume occupation ratio of the display medium in the gas space between the opposing substrates is preferably 5 to 70%, and more preferably 5 to 60%. If it exceeds 70%, the movement of the display medium is hindered, and if it is less than 5%, the contrast tends to be unclear.

Example

[0053] Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, and the present invention is not limited to the following Examples.

As white particles for negatively charged white display media, 10 parts by weight of titanium oxide (Typeta CR-50: manufactured by Ishihara Sangyo), 95 mol% of styrene monomer (Kanto Chemical Reagent) and 5 mol% of methacrylic acid (Kanto Chemical Reagent) In addition, a solution in which 5 parts by weight of a phenol condensate (Bontron E89: manufactured by Orient Chemical Co., Ltd.) and 2 parts by weight of lauryl peroxide (Perroll L: manufactured by NOF Corporation) as a negatively chargeable charge control agent is dissolved. Suspension, polymerized, filtered, and dried in purified water supplemented with 0.5% latemul E-1 18B (manufactured by Kao) as a surfactant, and then classified (MDS-2: Nihon-Eumatic Kogyo) ) To obtain white particles having an average particle size of 9. The charge amount of the obtained particles is 40 CZg, and the surface potential measurement is 0.3 seconds. The maximum value of the surface potential later was 430V. The Tg (glass transition temperature) of the resin component of the particles was 98 ° C. A white display medium was constituted by the group of white particles. The Tg (glass transition temperature) of styrene resin is 92 ° C, and the Tg (glass transition temperature) of methacrylic acid resin is 130 ° C. The whiteness of the obtained particles was measured with an image densitometer (RD918: manufactured by Darretag Macbeth). As a result, the optical density was 0.08, which was sufficient as whiteness.

<Production Example 2 of White Particles for White Display Medium (Styrene Z Divinylbenzene System: Polymerization Method)> As white particles for negatively charged white display medium, 30 parts by weight of titanium oxide and styrene monomer (Kanto Chemical) Reagents) 50mol% and dibuluenebenzene (Kanto Chemicals) 50mol%, a phenolic condensate (Bontron E89: manufactured by Orient Chemical) as a negatively charged charge control agent, 5 parts by weight, and 2 parts by weight of lauryl par A solution in which oxide (Peroil L: manufactured by Nippon Oil & Fats) was dissolved was suspended, polymerized, filtered, and dried in purified water supplemented with 0.5% LATEMUL E-118B (manufactured by Kao) as a surfactant. Thereafter, white particles having an average particle diameter of 9. O / zm were obtained using a classifier (MDS-2: Nippon-Umetic Kogyo). The obtained particles had a charge of 90 / z CZg, and the maximum value of the surface potential after 0.3 seconds of the surface potential measurement was 430V. A white display medium was constituted by the group of white particles. When the whiteness of the obtained particles was measured with an image densitometer (RD918: manufactured by Darretag Macbeth), the optical density was 0.07, which was sufficient as whiteness.

<Manufacturing Example 3 of White Particles for White Display Medium (Cycloolefin: Kneading / Crushing / Classification Method)> Cyclorefin resin (manufactured by Nippon Zeon Co., Ltd., trade name: ZENOA) 100 parts by weight of titanium oxide (Product name: CR90, manufactured by Ishihara Sangyo Co., Ltd.) 100 parts by weight, a phenol-based condensate (bontron E89: manufactured by Orient Chemical Co., Ltd.) as a negatively charged charge control agent, and 5 parts by weight of a Henschel-type mixer (FM50 '1 The resulting mixture is kneaded / granulated with a twin-screw extruder (KZ W15-45MG manufactured by Technobel), pelletized, And white particles having an average particle size of 9. O / zm were obtained. The charge amount of the obtained particles was 110 CZg, and the maximum value of the surface potential after 420 seconds of the surface potential measurement was 420V. A white display medium was composed of a group of white particles. The image density meter (RD918 : Gretag Macbeth Co.), the optical density was 0.07, which was sufficient as white.

[0057] <Production Example of White Particles for White Display Medium 4 (Methylpentene System: Kneading / Crushing / Classification Method)> Methylpentene resin (trade name: TPX) manufactured by Mitsui Chemicals Co., Ltd. Titanium oxide (made by Ishihara Sangyo Co., Ltd., trade name: CR60-2) 220 parts by weight, phenolic condensate as a negative charge control agent (Bontron E89: manufactured by Orienti Engineering) and 5 parts by weight of Henschel-type mixer (FM50) '1 Mitsui Mining Co., Ltd.) and the resulting mixture was kneaded / granulated with a twin-screw extruder (KZW 15-45MG Technobel Co., Ltd.), pelletized, The mixture was pulverized / classified using a Podget Mill Japan-Eumatic Co., Ltd. to obtain white particles having an average particle size of 8.7 μm. The charge amount of the obtained particles was 93 μCZg, and the maximum value of the surface potential after 0.3 seconds of the surface potential measurement was 440V. A white display medium was composed of a group of white particles. When the whiteness of the obtained particles was measured with an image densitometer (RD918: manufactured by Darretag Macbeth Co., Ltd.), the optical density was 0.07, which was sufficient as white.

As white particles for negatively charged white display media, 5 parts by weight of oxyhititanium (Typeta CR-50, manufactured by Ishihara Sangyo), 95 mol% of styrene monomer (Kanto Chemical Reagent) and 5 mol% of methacrylic acid (Kanto Chemical Reagent) As a negatively chargeable charge control agent, a phenolic condensate (Bontron E89: manufactured by Orient Chemical Co., Ltd.), 5 parts by weight, and 2 parts by weight of lauryl peroxide (Perroll L: manufactured by Nippon Oil & Fats) were dissolved in the interface. Suspend, polymerize, filter and dry 0.5% Latemul E-1 18B (manufactured by Kao) as an activator, filter, and dry, then classifier (MDS-2: Nihon-Eumatic Kogyo) As a result, white particles having an average particle size of 9. were obtained. The charge amount of the obtained particles was 37 CZg, and the maximum value of the surface potential after 420 seconds of the surface potential measurement was 420V. The Tg (glass transition temperature) of the resin component of the particles was 98 ° C. The whiteness of these white particles was measured with an image densitometer (RD918: manufactured by Darretag Macbeth Co., Ltd.), resulting in an optical density of 0.1, which was insufficient as whiteness.

<Production Example 6 of White Particles for White Display Medium (Methylpentene: Kneading / Crushing / Classification Method)> Methyl pentene oil (Mitsui Chemicals, Inc., trade name: TPX) 100 parts by weight, titanium oxide (Ishihara Sangyo, trade name: CR60-2) 600 parts by weight, phenolic as a negative charge control agent Condensate (Bontron E89: manufactured by Orienti Science Co., Ltd.) 5 parts by weight was mixed with a Henschel-type mixer (FM50 '1 manufactured by Mitsui Mining Co., Ltd.), and the resulting mixture was mixed with a twin screw extruder (KZW 15 -45MG Attempts were made to knead / granulate Perettoy rice cakes (manufactured by Technobel Co., Ltd.), but they could not be extruded and were unable to obtain the desired white particles.

[0060] <Production Example of White Particles for White Display Medium 7 (Methylpentene System: Kneading / Crushing / Classification Method)> Methylpentene resin (trade name: TPX) manufactured by Mitsui Chemicals Co., Ltd. Titanium oxide (made by Ishihara Sangyo Co., Ltd., trade name: CR60-2) 400 parts by weight, phenolic condensate as a negatively charged charge control agent (Bontron E89: manufactured by Orienti Engineering) and 5 parts by weight of Henschel type mixer (FM50) '1 Mitsui Mining Co., Ltd.) and the resulting mixture was kneaded / granulated with a twin-screw extruder (KZW 15-45MG Technobel Co., Ltd.), pelletized, A white particle having an average particle diameter of 8.7 m was obtained by pulverization / classification using a Podget mill (manufactured by Nippon Eumatic Co., Ltd.). When the whiteness of the obtained particles was measured with an image densitometer (RD918: manufactured by Daretag Macbeth), the result showed that the optical density was 0.07.

[0061] <Production Example 1 of Black Particles for Black Display Medium (Acrylic)>

As black particles for positively charged black display media, 98 parts by weight of methyl metatalylate monomer (Kanto Chemical Reagent) and Ataliloylmorpholine (ACMO: manufactured by Kojin Co., Ltd.) are used as a positively charged charge control agent. 3 parts by weight (Bontron N07: manufactured by Orient Chemical Co., Ltd.) and 10 parts by weight of carbon black (Special Black 5: manufactured by Tegussa) as a black pigment are dispersed by a sand mill, and 2 parts by weight of lauryl peroxide (Parol L: The liquid in which Nippon Oil & Fats was dissolved was suspended and combined in purified water to which 0.5% sodium polyoxyethylene alkyl ether sulfate (Latemul E-118B: manufactured by Kao) was added as a surfactant. After filtration and drying, black particles having an average particle size of 8.8 μm were obtained using a classifier (MDS-2: Nihon-Eumatic Kogyo). The charge amount of the obtained particles was +47 μCZg, and the maximum value of the surface potential after 450 seconds of the surface potential measurement was 450V. The Tg (glass transition temperature) of the rosin component of the particles was 110 ° C. This black particle group Thus, a black display medium was constructed. The Tg (glass transition temperature) of methyl metatalylate resin is 105 ° C, and the Tg (glass transition temperature) of attalyloylmorpholine resin is 145 ° C. When the blackness of the black particles was measured with an image densitometer (RD918: manufactured by Darretag Macbeth), the optical density was 1.3, which was sufficient as blackness.

[0062] <Example 2 of production of black particles for black display medium (acrylic)>

As black particles for positively charged black display media, 98 parts by weight of methyl metatalylate monomer (Kanto Chemical Reagent) and Ataliloylmorpholine (ACMO: manufactured by Kojin Co., Ltd.) are used as a positively charged charge control agent. 3 parts by weight (Bontron N07: manufactured by Orient Chemical Co., Ltd.) and 15 parts by weight of carbon black (Special Black 5: manufactured by Tegussa) as a black pigment are dispersed by a sand mill, and further 2 parts by weight of lauryl peroxide (Parol L: The liquid in which Nippon Oil & Fats was dissolved was suspended and combined in purified water to which 0.5% sodium polyoxyethylene alkyl ether sulfate (Latemul E-118B: manufactured by Kao) was added as a surfactant. After filtration and drying, black particles having an average particle diameter of 8.5 m were obtained using a classifier (MDS-2: Nihon-Umatic Co., Ltd.). The charge amount of the obtained particles could not be measured. In addition, the surface potential after 0.3 seconds of the surface potential measurement could not be measured. The Tg (glass transition temperature) of the rosin component of the particles was 110 ° C. A black display medium was constituted by the group of black particles. The Tg (glass transition temperature) of methyl metatalylate resin is 105 ° C, and the Tg (glass transition temperature) of attalyloylmorpholine resin is 145 ° C. When the blackness of the black particles was measured with an image densitometer (RD918: manufactured by Darretag Macbeth), the optical density was 1.3, which was sufficient as blackness.

[0063] <Example 3 of production of black particles for black display medium (acrylic)>

As black particles for positively charged black display media, 98 parts by weight of methyl metatalylate monomer (Kanto Chemical Reagent) and Ataliloylmorpholine (ACMO: manufactured by Kojin Co., Ltd.) are used as a positively charged charge control agent. (Bontron N07: manufactured by Orient Chemical) 3 parts by weight and carbon black as a black pigment (special black 5: manufactured by Tegussa) 0.05 parts by weight were dispersed by a sand mill, and further 2 parts by weight of lauryl peroxide (parol) (L: manufactured by NOF Corporation) was suspended in purified water to which 0.5% polyoxyethylene alkyl ether sodium sulfate (Latemul E-118B: manufactured by Kao) was added as a surfactant. After polymerization, filtration, and drying, black particles having an average particle size of 8.8 m were obtained using a classifier (MDS-2: Nihon-Umatic Co., Ltd.). The charge amount of the obtained particles was +40 CZg, and the maximum value of the surface potential was 470 V 0.3 seconds after the surface potential measurement. The Tg (glass transition temperature) of the rosin component of the particles was 110 ° C. When the blackness of the black particles was measured with an image densitometer (RD918: manufactured by Darretag Macbeth), an optical density of 1.2 was obtained, and the blackness was insufficient.

[0064] The display medium was charged by friction charging by mixing and stirring both display media in an equivalent amount.

[0065] "Production of information display panel"

A glass transparent substrate (20cm opening) with line electrodes (width: 300 μm, line pitch: 340 μm) on which ITO electrodes are placed is a photosensitive film-dry made by Zigo Morton Cells that fill the display medium by laminating film photoresist NIT250, forming barrier ribs (width: 20 m, height: 50 m) corresponding to the pixel size by exposure and development, and filling the display medium (rectangular, grid-like) Arrangement) was prepared.

On the other substrate, a glass transparent substrate provided with a copper comb line electrode (width: 300 μm, line pitch: 340 μm) was prepared.

[0066] Next, a white display medium and a black display medium having different charging characteristics were first filled with the white display medium into the cells on the display side substrate provided with the partition walls, and then filled with the black display medium. . The filling arrangement amount of both display media was kept the same volume, and the volume occupation ratio of the two display media combined between the two substrates was adjusted to 25 vol%.

[0067] Next, the other substrate is placed on the substrate in which the display medium is filled and arranged in the cell so that the line-shaped electrodes face each other at right angles, and the outer peripheral portion around the substrate is bonded with an epoxy adhesive. Then, a display medium was sealed and an information display panel was produced.

[0068] "Evaluation of information display panel"

Ten information display panels described in Example 2 and Comparative Example 1 were each manufactured and incorporated in an information display device, and voltage was applied to the electrodes so as to display a solid image and a staggered lattice image. The quality of the displayed image was visually observed and evaluated.

[0069] <Example 1> A combination of the white display medium composed of the white particles produced in Production Example 1 of white particles for white display medium and the black display medium comprised of the black particles produced in Production Example 1 of black particles for black display medium An information display panel was prepared and evaluated according to the above. Table the results

Shown in 1.

A combination of the white display medium composed of the white particles prepared in Production Example 2 of white particles for white display medium and the black display medium composed of the black particles produced in Production Example 1 of black particles for black display medium An information display panel was prepared and evaluated according to the above. The results are shown in Table 1.

A combination of the white display medium composed of the white particles produced in Production Example 3 of white particles for white display medium and the black display medium comprised of the black particles produced in Production Example 1 of black particles for black display medium An information display panel was prepared and evaluated according to the above. The results are shown in Table 1.

A combination of the white display medium composed of the white particles prepared in Production Example 4 of white particles for white display medium and the black display medium composed of the black particles produced in Production Example 1 of black particles for black display medium An information display panel was prepared and evaluated according to the above. The results are shown in Table 1.

[0073] <Comparative Example 1>

A combination of the white display medium composed of the white particles produced in Production Example 1 of white particles for white display medium and the black display medium comprised of the black particles produced in Production Example 2 of black particles for black display medium An information display panel was prepared and evaluated according to the above. The results are shown in Table 1.

[0074] <Comparative Example 2>

A combination of the white display medium composed of the white particles produced in Production Example 3 of white particles for white display medium and the black display medium comprised of the black particles produced in Production Example 2 of black particles for black display medium An information display panel was prepared and evaluated according to the above. Table the results Shown in 1.

[0075] [Table 1]

Industrial applicability

[0076] An information display panel and an information display device using the same according to the present invention include a display unit of an electronic device such as a notebook computer, PDA, mobile phone, handy terminal, electronic book, electronic newspaper, electronic manual (instruction manual). ) And other electronic paper, billboards such as signboards, posters, and blackboards, calculators, home appliances, display parts for automobiles, point cards, smart cards, etc., electronic advertisements, information boards, electronic POP (Point Of Presence, Point Of Purchase advertising), electronic shelf label, electronic price tag, electronic score, display unit of RF-ID device, etc. In addition, display of external electric field drive system that rewrites display by electric field drive by external electric field forming means It is suitably used for panels (so-called rewritable paper).

Claims

The scope of the claims

[1] In an information display panel having a structure in which a black and white two-color display medium having different electrode properties is enclosed between two opposing gas cavities in which at least one substrate is transparent, the charging polarities are mutually A white display medium comprising at least white particles containing at least titanium oxide and a charge control agent imparting negative chargeability, and at least carbon black and charge control imparting positive chargeability to two different black and white display media And a black display medium containing at least black particles containing an agent.

[2] An information display panel having a structure in which a black and white two-color display medium having different electrode properties is sealed between two opposing gas cavities in which at least one substrate is transparent and facing each other. A space between the two substrates that maintains the gap between the substrates and that partitions the space between the substrates is provided continuously or intermittently. An information display panel having a structure in which a display medium is encapsulated, each unit pixel is composed of three cells, and three color filters having transparent three primary colors are provided on at least the substrate side which is the display surface side. A black and white display medium having different charging polarities, a white display medium containing at least white particles containing at least titanium oxide and a charge control agent imparting negative chargeability, and at least a carbon black. And a black display medium including at least black particles containing a charge control agent imparting positive chargeability and an information display panel.

[3] The information display panel according to claim 1 or 2, wherein the titanium oxide contained in the white particles constituting the white display medium having a negatively charged polarity is 10 parts by weight or more.

[4] The information display panel according to claim 1 or 2, wherein the carbon black contained in the black particles constituting the black display medium of positive charge polarity is 0.1 to 10 parts by weight.