JP4679164B2 - Manufacturing method of information display panel and information display panel - Google Patents

Description

  The present invention relates to a method for manufacturing an information display panel and an information display panel. In particular, the present invention relates to a reversible method that can repeatedly display information such as images by moving a display medium by means of an electric field force or a Coulomb force. The present invention relates to a method for manufacturing a sex information display panel and a reversible information display panel.

  2. Description of the Related Art Conventionally, information display devices that use technologies such as electrophoresis, toner (particle) transfer, electrochromic, thermal, and two-color particle rotation have been proposed as information displays that replace liquid crystal (LCD). Yes.

  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. In particular, recently, an electrophoretic method (for example, see Non-Patent Document 1) in which a dispersion composed of dispersed particles and a colored solution is microencapsulated and disposed between opposing substrates has been proposed and is expected. It has been.

  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, this method has a problem that the structure is complicated because the charge transport layer and further the charge generation layer are arranged, and that it is difficult to inject the charges into the conductive particles, so that the stability is lacking. .

  In order to solve the various problems described above, particularly recently, there is also a method in which two types of display media (particle groups, etc.) having different optical characteristics and charging characteristics are arranged between substrates filled with a gas such as air. Proposed. In the case of such a dry display medium moving display system, it is necessary to generate an electric field in the substrate in order to drive (move) the display medium, but in order to reduce power consumption, an electric field is generated in the substrate. It is desired that the voltage applied for generation is as low as possible.

趙 Kuniori and three others, “New Toner Display Device (I)”, July 21, 1999, Annual Meeting of the Imaging Society of Japan (83 times in total) “Japan Hardcopy’99”, p.249-252

  In the information display panel used in the dry display medium moving display method as described above, as a method of filling the display medium between the substrates, the display medium is filled by pushing between the substrates using a blade or the like, Sprinkling and filling has been performed using a granular material spraying device or a granular charge spraying device. In the conventional information display panel manufactured as described above, the particle mobility (which is considered to be caused by the variation in the charging property of the display medium particles constituting the display medium in the display medium filled between the substrates) Therefore, it is necessary to apply a sufficiently large electric field to drive (move) all of the particles filled as the display medium, thereby driving the display medium. There is a problem that the voltage applied to generate an electric field becomes high, and the display information is good because the particles that are driven and the particles that are not driven are present in one type of display medium when a certain voltage is applied. This causes a problem that a high contrast cannot be obtained.

  The present invention has been intensively studied in view of the above circumstances, and has a mobility as display medium particles constituting at least one type of display medium when a display medium is filled and arranged between substrates of an information display panel. An information display panel that can drive a display medium at a low voltage and obtain a good contrast as display information by providing a method for selectively filling and arranging display medium particles between the substrates. The purpose is to provide.

  In order to achieve the above object, a method for producing an information display panel according to the present invention includes at least one kind of optical reflection composed of at least one kind of particles between two opposing substrates, at least one of which is transparent. In a method for manufacturing an information display panel in which information is displayed by enclosing a display medium having a rate and chargeability and moving the display medium by applying an electric field to the display medium, the display medium is filled between the substrates. Display medium charging and supplying process for charging display medium to supply, display medium one-layer aligning process for aligning and placing one layer of charged display medium on flat surface, and single-layer aligning and mounting on flat surface A display medium electric field moving filling step of moving and filling the display medium particles moving by applying a predetermined electric field from the display medium onto the substrate.

  As a preferred example of the method for manufacturing an information display panel according to the present invention, the display medium charge supplying step and the display medium single layer aligning step are configured using a granular charge spraying device, and the display medium charge supplying step. The display medium single layer aligning step is configured by passing the display medium through a gap space between the surface of the flat surface and the blade, and the display medium electric field transfer filling step is performed by an electric field disposed on the back side of the substrate. The display medium electric field transfer filling step includes forming information on the substrate by forming an electric field formed between the forming electrode and an electrode disposed on the back side of the flat surface on which one layer of the charged display medium is arranged and placed. An electric field formed between an electrode provided in advance as a display electrode and an electrode disposed on the back side of a flat surface on which a single layer of charged display medium is arranged and placed; and示媒 body be particles or liquid powders, there is.

  The information display panel of the present invention is manufactured using the method for manufacturing an information display panel according to any one of claims 1 to 6.

  According to the method for manufacturing an information display panel of the present invention, at least one or more types of optical reflectivity and chargeability composed of at least one type of particles between two opposing substrates, at least one of which is transparent. In a method of manufacturing an information display panel that displays information by enclosing a display medium having a liquid crystal display and moving the display medium by applying an electric field to the display medium, the display medium is charged when the display medium is filled between the substrates. A display medium electrification supply step to be supplied, a display medium single layer alignment step of placing a charged display medium on a flat surface, and a display medium having a single layer alignment placement on a flat surface Display medium electric field moving and filling step of moving and filling the display medium particles moving by applying a predetermined electric field from the substrate onto the substrate, so that the display medium is filled and arranged between the substrates of the information display panel. When, as a particles for display media constituting at least one type of display media, mobility will be able selectively filled disposed between the substrates equivalent particles for display media. Therefore, when a constant voltage is applied as a voltage applied to generate an electric field for driving the display medium, particles that are driven and particles that are not driven are not present in one type of display medium. All the display media that you want to drive can be moved (driven) accordingly, so the high voltage required to move the particles for display media that are difficult to move becomes unnecessary, and the display media is driven with the appropriate voltage. This makes it possible to manufacture an information display panel that can provide good contrast as display information. The information display panel manufactured by the method for manufacturing an information display panel of the present invention can be used as an information display panel that can drive a display medium at a low voltage.

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

  First, the configuration of the information display panel of the present invention will be described. In the information display panel of the present invention, an electric field is applied by some means in the substrate of the information display panel in which the display medium is sealed between the opposing substrates. The display medium charged according to the electric field direction is attracted by an electric field force or a Coulomb force, and the display medium reciprocates by switching the electric field direction, thereby displaying information. Therefore, it is necessary to design the information display panel so that the display medium moves uniformly and can maintain the stability when the display is rewritten repeatedly or when the display information is stored. 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 image force with the electrode, an intermolecular force, a liquid cross-linking force, gravity and the like can be considered.

An example of an information display panel applicable to the information display device of the present invention will be described with reference to FIGS. 1 (a) and (b) to FIGS. 3 (a) and 3 (b).
In the example shown in FIGS. 1 (a) and 1 (b), at least two or more types of display media 3 (here, a white display consisting of a group of particles) having different optical reflectance and charging characteristics composed of at least one type of particles. The black display medium 3B including the medium 3W and the particle group is moved in a direction perpendicular to the substrates 1 and 2 according to the electric field applied from the outside of the substrates 1 and 2, and the black display medium 3B is visually recognized by the observer. The white display is performed, or the white display medium 3W is visually recognized by the observer. In the example shown in FIG. 1B, in addition to the example shown in FIG. 1A, a partition 4 is provided between the substrates 1 and 2 to form a cell, for example.
In the example shown in FIGS. 2A and 2B, at least two or more types of display media 3 (here, a white display consisting of a group of particles) having different optical reflectance and charging characteristics composed of at least one type of particles. The substrate 1 corresponds to an electric field generated by applying a voltage between the electrode 5 provided on the substrate 1 and the electrode 6 provided on the substrate 2. 2, the black display medium 3 </ b> B is visually recognized by the observer and black display is performed, or the white display medium 3 </ b> W is visually recognized by the observer and white display is performed. In the example shown in FIG. 2 (b), in addition to the example shown in FIG. 2 (a), a partition 4 is provided between the substrates 1 and 2 to form cells, for example.
In the example shown in FIGS. 3A and 3B, a display medium 3 having at least one kind of optical reflectivity and chargeability composed of at least one kind of particles (here, a white display medium 3W composed of a group of particles). Is moved in a direction parallel to the substrates 1 and 2 in accordance with an electric field generated by applying a voltage between the electrode 5 and the electrode 6 provided on the substrate 1, and the white display medium 3W is observed. The color of the electrode 6 or the substrate 1 is displayed by the viewer, or the color of the electrode 6 or the substrate 1 is visually recognized by the viewer. In the example shown in FIG. 3B, in addition to the example shown in FIG. 3A, for example, a lattice-shaped partition wall 4 is provided between the substrates 1 and 2 to form a cell.
The above description is similarly applied to the case where the white display medium 3W including the particle group is replaced with the white display medium including the powder fluid and the black display medium 3B including the particle group is replaced with the black display medium including the powder fluid. be able to.

  As a method for manufacturing the above-described information display panel, the present invention is characterized in that a method of selecting particles for display medium that move by a predetermined electric field and filling between the substrates constituting the panel is used. In other words, since the chargeability of the charged and aligned particles varies, there are particles that are easy to move with respect to the applied electric field and particles that are difficult to move. Only easy particles are selected and filled between panel substrates.

4 to 6 are diagrams showing an example of a method for manufacturing an information display panel according to the present invention.
In FIG. 4, display medium particles 13 are supplied from a display medium supply device 11 onto a flat surface (flat plate) 12 a formed on the conveyance belt 12 on a conveyance belt 12 conveyed by a conveyance device (not shown). The display medium particles 13 are triboelectrically charged when passing through a gap formed in the lower part of the doctor blade 14 disposed in the forward direction of the transport belt 12 (indicated by the left-pointing arrow). The display medium charging and supplying step of charging the particles for charging and the display medium single layer alignment step of arranging and arranging the charged display medium particles 13 on the flat surface 12a in a single layer thickness are provided without being divided. Further, a predetermined electric field is applied from the display medium particles 13 arranged in a single layer on the flat surface 12a to the direction of travel of the transport belt 12 (left side of the doctor blade 14). Display media field moving filling step of filling the particles for display media 13 to move by moving on the substrate (panel substrate) is provided therefore. In this display medium electric field transfer filling step, electrodes 15 and 16 for applying a predetermined electric field to the display medium particles 13 aligned and placed on the flat surface 12a are disposed above the flat surface 12a. The electrode 16 is installed on the back side of the flat surface 12a on which the display medium particles 13 are arranged and placed. When a predetermined electric field is applied between the electrodes 15 and 16, only the particles for the display medium that can move with the predetermined electric field move to the substrate side (inside the cell formed by the partition walls) and are filled as shown. The display medium particles that have not moved due to the application of a predetermined electric field are collected in a particle collecting step (not shown) installed further in the traveling direction of the transport belt 12 and recycled.

  On the other hand, in FIG. 5, a display medium is applied on a flat surface (flat plate) 12 a formed on the transport belt 12 from the display medium charging / dispersing device 17 on the transport belt 12 transported by a transport device (not shown). When the particles 13 are distributed and supplied, the display medium particles 13 are triboelectrically charged, and are arranged and placed in a single layer thickness on the distributed flat surface 12a, whereby the display medium particles 13 are charged and supplied. The display medium charging supply step and the display medium single layer alignment step in which the charged display medium particles 13 are aligned and arranged in a single layer thickness on the flat surface 12a are provided without being divided. Note that the subsequent steps are the same as those described with reference to FIG.

Further, in FIG. 6, the display medium charge supplying step, the display medium single layer alignment step, and the display medium electric field transfer filling step shown in FIG. The panel substrate is filled with 13W and black display medium particles 13B. In addition, “display medium charge supply step of white display medium particles, display medium single layer alignment step and display medium electric field transfer filling step”, and “display medium charge supply step of black display medium particles, display, which are continuously performed” The medium single layer alignment step and the display medium electric field transfer filling step are not limited to the example of FIG. 6. For example, the “white display medium particle display medium charging supply step, display medium single layer alignment step, and The “display medium electric field transfer filling step” is performed in the steps shown in FIG. 4, and the “display medium charge supply step, display medium single layer alignment step and display medium electric field transfer filling step of particles for black display medium” are shown in FIG. Or the “display medium charging and supplying process for the white display medium particles, the display medium single layer alignment process and the display medium electric field transfer filling process” are performed in the process shown in FIG. The display medium charge supply step, the display medium single layer alignment step, and the display medium electric field transfer filling step ”are performed in the steps shown in FIG. 4 or“ white display medium particle display medium charge supply step, display medium single layer ” The alignment process and display medium electric field transfer filling process "and" display medium charge supply process of black display medium particles, display medium single layer alignment process and display medium electric field transfer filling process "are both performed in the steps shown in FIG. May be.
Further, in any of FIGS. 4, 5 and 6, the display substrate is provided in advance as an information display electrode instead of the electric field generating electrode installed on the back side of the panel substrate in the electric field transfer filling process. An electrode can also be used.

  According to the present invention, when the display medium is filled and arranged between the substrates of the information display panel, the display medium particles having the same mobility are selected as the display medium particles constituting at least one type of display medium. Since it is possible to fill and arrange between the substrates, the display particles that are driven and the particles that are not driven when one voltage is applied to generate an electric field for driving the display medium are one kind of display medium. High voltage required to move particles that are difficult to move because all display media that are not present in the display can be moved (driven) according to the electric field. Thus, an information display panel capable of driving a display medium with an appropriate voltage and obtaining a good contrast as display information can be manufactured. The information display panel manufactured by the method for manufacturing an information display panel according to the invention can be used as an information display panel that can drive a display medium at a low voltage.

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

  Regarding the substrate, at least one of the substrates is a transparent substrate from which the color of the display medium can be confirmed from the outside of the information display panel, and a material having high visible light transmittance and good heat resistance is preferable. The other substrate may be transparent or opaque. Examples of substrate materials include polymer sheets such as polyethylene terephthalate, polyethersulfone, polyethylene, polycarbonate, polyimide, and acrylic, flexible materials such as metal sheets, and flexible materials such as glass and quartz. There are no inorganic sheets. The thickness of the substrate is preferably 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 electrode forming material for the electrodes 5 and 6 when the electrodes are provided on the substrate of the information display panel includes metals such as aluminum, silver, nickel, copper and gold, ITO, indium oxide, conductive tin oxide, conductive oxide Examples include conductive metal oxides such as zinc, and conductive polymers such as polyaniline, polypyrrole, and polythiophene, which are appropriately selected and used. As a method for forming an electrode, a method of forming the above-described materials into a thin film by sputtering, vacuum deposition, CVD (chemical vapor deposition), coating, or the like, or mixing a conductive agent with a solvent or a synthetic resin binder. A method of applying is used. In many cases, the electrode provided on the display surface side substrate needs to be transparent, but the electrode provided on the back surface side substrate does not need to be transparent. In any case, the above-mentioned material which can be patterned and is conductive can be preferably used. Note that the electrode thickness is not particularly limited as long as the conductivity can be secured and the light transmittance is not hindered, and is preferably 3 to 1000 nm, preferably 5 to 400 nm. The material and thickness of the electrode provided on the back side substrate are the same as those of the electrode provided on the display surface side substrate described above, but need not be transparent. In this case, the external voltage input may be superimposed with direct current or alternating current.

  The partition 4 provided on the substrate as required is optimally set depending on the type of display medium involved in display, and is not limited in general. However, the width of the partition is 2 to 100 μm, preferably 3 to 50 μm. The height of the partition wall is adjusted to 10 to 500 μm, preferably 10 to 200 μm. In forming the partition walls, a both-rib method in which ribs are formed on each of the opposing substrates and then bonded, and a one-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. 7, the cells formed by the partition walls made of these ribs are illustrated in a square shape, a triangular shape, a line shape, a circular shape, and a hexagonal shape as viewed from the substrate plane direction. 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 clearness of information display increases. 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 photolithography method using a resist film and a mold transfer method are preferably 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 as the display medium 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 that exhibits high fluidity in an aerosol state in which solid particles are stably suspended as a dispersoid, for example, as a display medium, between opposing substrates, at least one of which is transparent. Such a powder fluid can be easily and stably moved by a Coulomb force or the like by applying a low voltage.
As described above, for example, the powder fluid used as the display medium in the present invention is a substance in the intermediate state between the 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, a solid substance is used in a state of relatively stably floating 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 yellow lead, 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.

  Further, the particles of the present invention 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, and if it is smaller than this range, the cohesive force between the particles becomes too large, which hinders the movement of the particles.

Furthermore, in the present invention, regarding the particle size distribution of each particle, the particle size distribution Span represented by the following formula is less than 5, preferably less than 3.
Span = (d (0.9) −d (0.1)) / d (0.5)
(However, d (0.5) is a numerical value expressing the particle diameter in μm that 50% of the particles are larger than this and 50% is smaller than this, and d (0.1) is a particle in which the ratio of the smaller particles is 10%. (Numerical value expressed in μm, and d (0.9) is a numerical value expressed in μm for a particle diameter of 90% or less.)
By keeping Span within a range of 5 or less, the size of each particle is uniform, and uniform particle movement becomes possible.

  Furthermore, regarding the correlation between the particles, the ratio of d (0.5) of the particles having the minimum diameter to d (0.5) of the particles having the maximum diameter among the used particles is set to 50 or less, preferably 10 or less. It is essential. 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, particles are introduced 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.

  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, in the present invention, when a display medium such as a particle group or a powdered fluid is used for a dry information display panel, it is important to manage the gas in the void 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, more preferably 35% RH or less with respect to the humidity of the gas in the gap.
1A, 1B, 3A, and 3B, the gaps are defined as electrodes 5 and 6 (electrodes are formed on the inner side of the substrate) from portions sandwiched between the opposing substrates 1 and 2. Gas portion in contact with a so-called display medium, excluding the occupied portion of the display medium (particle group or powdered fluid) 3, the occupied portion of the partition wall 4 (when provided with the partition wall), and the seal portion of the information display panel. Shall be pointed to.
The gas in the gap is not limited as long as it is in the humidity region described above, but dry air, dry nitrogen, dry argon, dry helium, dry carbon dioxide, dry methane, and the like are preferable. This gas needs to be sealed in an information display panel so that the humidity is maintained, for example, filling a display medium, assembling an information display panel, etc. in a predetermined humidity environment, It is important to apply a sealing material and a sealing method that prevent moisture from entering from the outside.

The distance between the substrates in the information display panel 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.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples of the present invention, but the present invention is not limited to the following examples. In addition, the information display panel of an Example and a comparative example evaluated what produced by the following method according to the following reference | standard.

"Preparation of display media"
In Examples and Comparative Examples, black and white two-color particle groups (particle group A and particle group B) having different charging characteristics were used as display media.
Particle group A consists of acrylic urethane resin EAU53B (manufactured by Asia Industry Co., Ltd.) / IPDI-based cross-linking agent Excel Hardener HX (manufactured by Asia Industry Co., Ltd.) and carbon black (MA100 Mitsubishi Chemical Corporation) 4 parts by weight, charge control 2 parts by weight of the agent Bontron N07 (Orient Chemical Co., Ltd.) was added, kneaded, pulverized with a jet mill, and mechanical impact force was applied using a hybridizer device (Nara Machinery Co., Ltd.). In addition, classification was made after making it approximately spherical. The produced particle group A was an approximately spherical and negatively charged black particle group having an average particle diameter of 9.1 μm.
Particle group B was prepared by dissolving 0.5 part by weight of AIBN (azobisisobutyronitrile) in 80 parts by weight of tertiary butyl methacrylate monomer and 20 parts by weight of 2- (diethylamino) ethyl methacrylate. The liquid obtained by dispersing 20 parts by weight of titanium oxide made lipophilic by treatment with an agent is suspended and polymerized in an aqueous solution of 0.5% surfactant (sodium lauryl sulfate), filtered, dried. Then, it was prepared using a classifier (MDS-2: Nippon Numatic Industries). The produced particle group B is a positively chargeable spherical white particle having an average particle diameter of 8.5 μm.

"Evaluation of information display panel"
The information display panels described in the following Examples 1 to 3 and Comparative Examples 1 and 2 are incorporated into an information display device, and a voltage of 80 V is applied to rewrite the white solid image display and the black solid image display. The optical density of the image was measured using a reflection image densitometer (RD918, manufactured by Macbeth), and the contrast (reflection density when displaying a black solid image / reflection density when displaying a solid white image) was measured and evaluated based on the quality of the contrast.

<Example 1>
A glass transparent substrate with ITO electrodes (7 cm × 7 cm □) was prepared, ribs having a height of 50 μm were formed on one substrate, and square-shaped and grid-shaped partition walls were formed.
The partition wall was formed as follows. A dry film photoresist NIT250 made by Nichigo Morton, which is a photosensitive film, was laminated on a glass with ITO, and a partition wall having desired lines of 30 μm, spaces of 320 μm, and pitch of 350 μm was formed by exposure and development.
As the other substrate, a glass transparent substrate with ITO electrodes (7 cm × 7 cm □) was prepared.

Next, two types of particle groups (particle group A and particle group B) having different colors and charging characteristics are formed in the same order as described above with reference to FIG. The cell was filled.
First, the particle group A is
(1) Using a particle charging / dispersing device (for example, a display medium charging / dispersing device shown in FIG. 5), the particles are dispersed and aligned so as to form one layer on a flat surface,
(2) Next, it is arranged between two electrodes installed in the display medium electric field transfer process so that the flat surface where the particle groups of one layer are aligned is down and the substrate filling the particle groups is up. And
(3) An electric field is generated between the electrodes, and only particles moving in the applied electric field out of a group of particles dispersed and arranged on a flat surface are allowed to fly upward and move in the cell of the substrate disposed above. Was filled with a predetermined amount.
Subsequently, also for the particle group B, according to the procedure described in the above (1) to (3), a predetermined amount was filled in the cell of the substrate previously filled with the particle group A over the particle group A. .
In the filling step, the packing arrangement amount of the particle group A and the particle group B is the same volume amount, and the volume occupancy ratio of both particle groups with respect to the space between the substrates formed by bonding the two substrates is 25 vol%. Adjusted as follows.
Next, the substrate in which the particle group is filled and arranged in the cell and the other substrate are overlapped with each other, and the outer peripheral portion around the substrate is adhered and sealed with an epoxy adhesive, and the display medium (particle group A) is sealed. And particle group B) were encapsulated to produce an information display panel.

<Example 2>
The process of filling the particles by moving the particles from the flat surface in which the particles of one layer are aligned into the cell of the substrate is performed between the electrode placed on the back side of the flat surface and the ITO electrode previously formed on the substrate. An information display panel was produced in the same manner as in Example 1 except that the operation was performed by the generated electric field.

<Example 3>
An information display panel was produced in the same manner as in Example 1 except that the order of filling the particle group A and the particle group B was reversed.

<Comparative Example 1>
Using a charged particle spraying device, a predetermined amount of display medium (particle group A and particle group B) is sprayed in the order of particle group A and particle group B directly onto the substrate on which the partition walls are formed, and the cell of the substrate An information display panel was produced in the same manner as in Example 1 except that the inside was filled. That is, without using the display medium electric field transfer filling step used in Examples 1 to 3, the display medium was filled to produce an information display panel.

<Comparative Example 2>
A predetermined amount of display medium (particle group A and particle group) in the order of particle group B and particle group A (order opposite to that of Comparative Example 1) is directly formed on the substrate on which the partition walls are formed using the particle charging and dispersing device. An information display panel was produced in the same manner as in Example 1 except that B) was sprayed and filled in the cells of the substrate. That is, without using the display medium electric field transfer filling step used in Examples 1 to 3, the display medium was filled to produce an information display panel.

The evaluation results of the above information display panel are shown in Table 1.
In the information display panels of Examples 1 to 3 using the information display panel produced by filling the display medium particles in the electric field transfer filling process of the present invention, the black solid display image has a darker display image density. As a result, a whiter display image density was obtained in the white solid display image, and as a result, a good contrast of 3 or more was obtained.
On the other hand, in the information display panels of Comparative Examples 1 and 2 using the information display panels prepared by filling the display medium particles without using the electric field transfer filling process of the present invention, the black solid display image density , The blackness was insufficient, the white solid display image density was insufficient whiteness, and the contrast was insufficient.
From these results, since the information display panels of Examples 1 to 3 used the display medium composed of particles that can move with a predetermined electric field, white particles are opposite to the display surface side substrate when displaying a black solid image. The black particles move to the substrate on the opposite side of the display surface side substrate and do not remain on the display surface side when the white solid image is displayed. On the other hand, in the information display panels of Comparative Examples 1 and 2, since the display medium composed of all the charged particle groups is used, the particles that are difficult to move with respect to the same electric field do not move and the display image Therefore, white particles that cannot move to the substrate on the opposite side of the display surface side substrate remain when the black solid image is displayed, and remain on the substrate opposite to the display surface side substrate even when the white solid image is displayed. Uniform because black particles that cannot move remain on the display surface side That the display can not be performed it has been confirmed.

  An information display panel produced by the manufacturing method of the present invention and an information display device equipped with the panel are a display unit of a mobile device such as a notebook computer, a PDA, a mobile phone, and a handy terminal, an electronic paper such as an electronic book and an electronic newspaper, Billboards such as billboards, posters, blackboards, calculators, home appliances, automotive supplies, card displays such as point cards, IC cards, electronic advertisements, electronic POPs, electronic shelf labels, electronic price tags, electronic musical scores, RF- It is suitably used for a display unit of an ID device.

(A), (b) is a figure which shows an example of the information display panel of this invention. (A), (b) is a figure which shows the other example of the information display panel of this invention. (A), (b) is a figure which shows the further another example of the information display panel of this invention. It is a figure which shows an example of the manufacturing method of the information display panel of this invention. It is a figure which shows an example of the manufacturing method of the information display panel of this invention. It is a figure which shows an example of the manufacturing method of the information display panel of this invention. It is a figure which shows an example of the shape of the partition in the information display panel of this invention.

Explanation of symbols

1 Substrate 2 Substrate 3 Display medium (particle group, powder fluid)
3W White display medium 3B Black display medium 4 Partition 5 Electrode 6 Electrode 11 Display medium supply device 12 Conveying belt 12a Flat surface (flat plate)
13 Display Media Particles 14 Doctor Blade 15, 16 Electrode 17 Display Media Charge Supply (Spreading) Device

Claims (7)

At least one display medium having at least one type of optical reflectivity and charging property is sealed between two opposing substrates, at least one of which is transparent, and an electric field is applied to the display medium. In the method of manufacturing an information display panel for displaying information by moving the display medium, the filling of the display medium between the substrates,
A display medium charging and supplying step of charging and supplying the display medium;
A display medium single layer aligning step of placing a charged display medium on a flat surface in a single layer alignment;
A display medium electric field moving and filling step of moving and filling the display medium particles moving by applying a predetermined electric field from the display medium arranged and arranged in a single layer on the flat surface onto the substrate;
A method for producing an information display panel, comprising:   2. The information display panel according to claim 1, wherein the display medium charge supply step and the display medium single layer alignment step are configured by using a display medium charge distribution device in the method for manufacturing the information display panel. Panel manufacturing method.   In the method for manufacturing the information display panel, the display medium charging supply step and the display medium single layer alignment step are configured by passing the display medium through a gap space between the surface of the flat surface and the blade. The method for manufacturing an information display panel according to claim 1, wherein:   In the method for manufacturing an information display panel, the display medium electric field movement filling step includes an electric field forming electrode arranged on the back side of the substrate and an electrode arranged on the back side of the flat surface on which one layer of charged display media is arranged and mounted. The method for manufacturing an information display panel according to any one of claims 1 to 3, wherein the method is configured by an electric field formed therebetween.   In the method for manufacturing an information display panel, the display medium electric field movement filling step is arranged on the back side of a flat surface on which an electrode provided in advance as an information display electrode on a substrate and a single layer of a charged display medium are arranged and placed. The method for manufacturing an information display panel according to claim 1, wherein the information display panel is configured by an electric field formed between the electrodes.   The method for manufacturing an information display panel according to claim 1, wherein the display medium is a particle group or a powder fluid.   It manufactures using the manufacturing method of the information display panel of any one of Claims 1-6, The information display panel characterized by the above-mentioned.

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