JP2006058563A - Panel for image display and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a panel for image display capable of reducing a sticking force of image display medium and lowering a driving voltage without damaging conductivity of an electrode and appearance and to provide its manufacturing method. <P>SOLUTION: In the panel for image display, the image display medium 3 is enclosed between two sheets of substrates 1, 2 of which at least one side is transparent, the image display medium is moved by applying an electric field to the image display medium and, thereby, an image is displayed, wherein a thin film layer comprising fluorine based compound of low molecular weight is disposed in the substrate. Further, the thin film layer is formed as follow; the fluorine based compound of low molecular weight is applied in the substrate, the applied fluorine based compound is hydrolyzed, thereby, a film is uniformly formed in a molecular level and, thereafter, the excessive fluorine based compound is cleaned and removed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image display panel for displaying an image by moving an image display medium by enclosing the image display medium between two substrates, at least one of which is transparent, and applying an electric field to the image display medium. It relates to a manufacturing method.

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

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

  However, the electrophoresis method has a problem that the response speed becomes slow due to the viscous resistance of the liquid because the particles migrate in the liquid. Furthermore, 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 of lack of image repetition stability. . 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, the structure is complicated because the charge transport layer and further the charge generation layer are arranged, and it is difficult to inject the charges into the conductive particles.

As one method for solving the various problems described above, after encapsulating the image display medium between two opposing substrates, at least one of which is transparent, or by forming cells isolated from each other by a partition wall, An image display panel is known that displays an image by enclosing an image display medium in a cell and then applying an electric field to the image display medium to move the image display medium.
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” Proceedings, p.249-252

In the above-described image display panel, the image display medium enclosed between the substrates (in the cell defined by the partition walls when the partition walls are provided) is instantaneously moved between the substrates in accordance with the applied electric field. There is a need. However, depending on the case, there is a problem that the image display medium adheres to the surface of the substrate or, if present, the partition wall surface and the electrode surface provided in the substrate, and the drive voltage increases. In addition, in order to solve this problem, it has been studied to treat the substrate with SiO ₂ , fluororesin, polycarbonate, etc., but any of them can reduce the adhesion of the image display medium. There was also a slight problem, and there was a problem with the film appearance.

  An object of the present invention is to solve the above-mentioned problems, and to reduce the adhesion of the image display medium and reduce the driving voltage without impairing the conductivity and appearance of the electrode, and the manufacturing thereof. Is to provide a method.

  The image display panel of the present invention is an image in which an image display medium is sealed between two substrates, at least one of which is transparent, and an image is displayed by moving the image display medium by applying an electric field to the image display medium. In the display panel, a thin film layer made of a fluorine-based compound having a low molecular weight is provided in the substrate.

  As a suitable example of the panel for image display of this invention, the thin film layer has coat | covered the electrode surface provided in the board | substrate at least, the thickness of the thin film layer was 0.5-500 nm, and fluorine type The molecular weight of the compound may be 50-20000.

  The image display panel manufacturing method of the present invention is a method for manufacturing an image display panel having the above-described configuration, in which a fluorine-based compound having a low molecular weight is applied in a substrate and the applied fluorine-based compound is hydrolyzed. The film is uniformly formed at the molecular level, and then the excess fluorine-based compound is washed away.

  In the present invention, a fluorine compound having a low molecular weight is applied to the substrate, and the applied fluorine compound is hydrolyzed to form a film uniformly at the molecular level, and then the excess fluorine compound is removed by washing. By providing a thin film layer made of a low molecular weight fluorine-based compound in the substrate, the adhesion of the image display medium can be reduced without impairing the conductivity and appearance of the electrode, and the driving voltage is reduced. be able to.

  First, a basic configuration of an image display panel that is an object of the present invention will be described. In the image display panel used in the present invention, an electric field is applied to an image display medium sealed between two opposing substrates. Along with the applied electric field direction, the image display medium charged at a low potential toward the high potential side is attracted by the force of the electric field or the Coulomb force, and is charged at a high potential toward the low potential side. The image display medium is attracted by an electric field force, a Coulomb force, or the like, and the image display medium is reciprocated by a change in the electric field direction due to the potential switching, thereby displaying an image. Therefore, it is necessary to design the image display panel so that the image display medium moves uniformly and can maintain stability during repetition or storage. Here, as the force applied to the particles constituting the image display medium, in addition to the force attracted by the Coulomb force between the particles, the electric image force with the electrode and the substrate, the intermolecular force, the liquid cross-linking force, gravity and the like can be considered. .

An example of an image display panel which is an object of the present invention will be described with reference to FIGS. 1 (a) and (b) to FIGS. 3 (a) and 3 (b).
In the example shown in FIGS. 1A and 1B, an image display medium 3 (here, white particles 3W and black particles 3B are shown) having different colors and charging characteristics composed of at least one kind of particles is used as a substrate. Depending on the electric field applied from the outside of 1 and 2, the substrate is moved perpendicularly to the substrates 1 and 2 and the black particles 3B are visually recognized by the observer to display black, or the white particles 3W are visually recognized by the observer. To display a white color. In the example shown in FIG. 1B, in addition to the example shown in FIG. 1A, partition walls 4 are provided, for example, in a lattice shape between the substrates 1 and 2 to define display cells.
In the example shown in FIGS. 2A and 2B, an image display medium 3 (in this case, white particles 3W and black particles 3B) having different colors and charging characteristics composed of at least one kind of particles is used as a substrate. 1 is moved perpendicularly to the substrates 1 and 2 in accordance with the electric field generated by applying a voltage between the electrode 6 provided on the substrate 1 and the electrode 5 provided on the substrate 2, and the black particles 3B are visually recognized by the observer. Thus, black display is performed, or white particles 3W are visually recognized by an observer to perform white display. In the example shown in FIG. 2B, in addition to the example shown in FIG. 2A, partition walls 4 are provided, for example, in a lattice form between the substrates 1 and 2 to define display cells.
In the example shown in FIGS. 3A and 3B, an image display medium 3 (in this case, white particles 3W) having one color of chargeability is disposed between the electrode 5 and the electrode 6 provided on the substrate 2. In accordance with the electric field generated by applying a voltage to the substrate 1, it is moved in a direction parallel to the substrates 1 and 2, and the white particles 3W are visually recognized by the observer, or the color of the electrode 6 or the substrate 1 is displayed. The color of the electrode 6 or the substrate 1 is displayed by the observer. In the example shown in FIG. 3B, partition walls 4 are provided between the substrates 1 and 2, for example, in a lattice shape to define display cells.
The above description can be similarly applied to the case where the white particles 3W are replaced with the white powder fluid and the black particles 3B are replaced with the black powder fluid.

  The image display panel according to the present invention is characterized in that a thin film layer made of a fluorine-based compound having a low molecular weight is formed in the substrate, particularly on the electrode, so that the adhesion of the image display medium and the substrate surface, particularly the electrode, is greatly reduced. Since the thickness is reduced and the thin film layer is thin, the conductivity and appearance of the electrode are not impaired even if the thin film layer is provided on the electrode. As a result, the movement of the image display medium becomes smooth and the drive voltage can be reduced.

  In the image display panel of the present invention, the thickness of the thin film layer is not particularly limited, but is preferably in the range of 0.5 to 500 nm, and more preferably in the range of 1 to 20 nm. If the film thickness is less than 0.5 nm, the molecular design limit of the fluorine compound as the treatment agent will be reached. On the other hand, if the film thickness is more than 500 nm, the conductivity will be impaired and the display will be charged. The characteristics are affected. Further, the molecular weight of the fluorine-based compound as the treating agent is not particularly limited as long as it is a low molecular weight, but a range of 50 to 20000 is preferable, and a range of 100 to 1000 is more preferable. Further, the conductivity of the electrode after forming the thin film layer is not particularly limited, but it is preferable if 50 to 100% of the conduction characteristics before forming the thin film layer can be secured, more preferably 85 to 100%. Further, the water repellency and oil repellency are not particularly limited, but the pure water contact angle preferably has a water repellency of 100 degrees or more, and the contact angle with ethylene glycol, jodomethane, 1 bromonaphthalene or the like is 50 degrees or more. It is preferable that If the contact angle is low, the adhesion cannot be reduced.

  In the image display panel of the present invention, as a method for producing the thin film layer, any method can be used as long as the thin film layer can be formed in the substrate, but the method described below can be used. preferable. First, a fluorine compound having a low molecular weight (one end has a functional group that reacts with a metal or the like) is applied to at least an electrode in the substrate. Next, the applied fluorine-based compound is hydrolyzed under normal temperature and normal humidity to high temperature and high humidity to uniformly form a film at the molecular level (points to be monofunctional). Thereafter, by cleaning the excess fluorine-based compound, the adhesion of the image display medium can be reduced without impairing the conductivity and appearance of the electrode.

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

  It is important that the partition wall 4 of the present invention is provided on a transparent substrate on the viewer side, and its shape is appropriately set appropriately depending on the type of image display medium involved in the display, and is not limited in general. The width is adjusted to 2 to 100 μm, preferably 3 to 50 μm, and the height of the partition wall is adjusted to 10 to 500 μm, preferably 10 to 200 μm. As shown in FIG. 4, the display cells formed by the partition walls made up of these ribs are exemplified by a square shape, a triangular shape, a line shape, a circular shape, and a hexagonal shape as viewed from the plane of the substrate. The shape and the mesh shape are exemplified. It is better to make the portion corresponding to the cross section of the partition wall visible from the display side (the area of the frame portion of the display cell) as small as possible, and the sharpness of the image display increases.

  As for the substrate, at least the substrate on the viewer side is the transparent substrate 1 in which the color of the image display medium can be confirmed from the outside of the image display panel, and a material having high visible light transmittance and good heat resistance is suitable. is there. The substrate 2 serving as the other back side 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 transparent substrate is preferably 2 to 5000 μm, more preferably 5 to 2000 μm, and the thickness of the back substrate is preferably 20 to 5000 μm, and more preferably 30 to 2000 μm. If any of the substrates is too thin, it is difficult to maintain strength and uniformity between the substrates, and if it is thicker than 5000 μm, it is inconvenient for an image display panel mounted on a thin image display device.

  Regarding the electrode provided as necessary, the electrode 6 provided on the side of the substrate 1 that needs to be transparent on the viewing side is formed of a conductive material that is transparent and can be patterned, and is formed of aluminum, silver, nickel, copper, Examples include metals such as gold, conductive metal oxides such as ITO, indium oxide, conductive tin oxide, and conductive zinc oxide, and conductive polymers such as polyaniline, polypyrrole, and polythiophene. It is done. 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. The method of apply | coating is 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, thickness, and the like of the electrode 5 provided on the substrate 2 side on the back side are the same as those of the electrode 6 described above, but need not be transparent. In this case, the external voltage input may be superimposed with direct current or alternating current.

  Next, the powder fluid as an image display medium used in the image display panel of the present invention will be described. As for the name of the powder fluid as the image display medium of the present invention, the present applicant has obtained the right of “Electronic Powder Fluid (registered trademark)”.

  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, a dispersion system in which a solid or liquid substance is stably suspended as a dispersoid in a gas, and the solid substance is used as a dispersoid in the image display device of the present invention. Is.

The image display panel of the present invention is a powder fluid exhibiting high fluidity in an aerosol state in which solid particles are stably suspended as a dispersoid, for example, as an image display medium between two opposing substrates, at least one of which is transparent. Such a powder fluid can be easily and stably moved by a Coulomb force by applying a low voltage.
As described above, for example, the powder fluid used in the present invention is a substance in an intermediate state between fluid and particles, which exhibits fluidity by itself without borrowing the force of gas or liquid. This powder fluid can be in an aerosol state in particular, and in the image display device of the present invention, a solid substance is used in a state of relatively stably floating as a dispersoid in the gas.

  Next, the particles as the image display medium used in the image display panel of the present invention will be described. 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, resol 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.

As yellow colorants, 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.

  Moreover, it is preferable that the particles used as the image display medium used in the image display panel of the present invention 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.

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

Furthermore, in the present invention, when a particle group or powder fluid is used for the image display medium, it is important to manage the gas in the void surrounding the image display medium 3 (particle group or powder fluid) 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 gap portion is defined by the electrodes 5 and 6 and the image display medium (particles) from the portion sandwiched between the opposing substrate 1 and substrate 2. Group or powdered fluid 3), a portion occupied by partition wall 4 (portion where partition walls defining incomplete cells are present), and a portion of gas contacted with a so-called image display medium excluding an apparatus seal portion. Shall.
The gas in the gap is not limited as long as it is in the humidity region described above, but dry air, dry nitrogen, dry argon, dry helium, dry carbon dioxide, dry methane, and the like are preferable. This gas needs to be sealed in the apparatus so that the humidity is maintained. For example, the image display medium is filled and the substrate is assembled in a predetermined humidity environment. It is important to apply a sealing material and a sealing method to prevent the above.

  The volume occupancy of the image display medium (particle group or powder fluid) 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 image display medium (particle group or powder fluid) is hindered, and when it is less than 5%, the contrast tends to be unclear.

  Hereinafter, in the method for manufacturing an image display panel of the present invention, in order to form a thin film layer, a study on a treatment agent used on a substrate, particularly on an electrode, for water / oil repellency verification, image display medium Description will be made in the order of adhesion evaluation and reversibility evaluation. In addition, the black particle group and white particle group used as an image display medium were produced as follows.

  The black particle group consists of acrylic urethane resin EAU53B (manufactured by Asia Kogyo Co., Ltd.) / IPDI crosslinking agent Excel Hardener HX (manufactured by Asia Kogyo Co., Ltd.), carbon black (MA100 Mitsubishi Chemical Co., Ltd.) 4 phr, charge control agent Bontron N07 (manufactured by Orient Chemical Co., Ltd.) 2 phr was added, kneaded, pulverized with a jet mill, and further applied with a mechanical impact force using a hybridizer device (manufactured by Nara Machinery Co., Ltd.) to form a substantially spherical shape. And then classified. The produced black particle group was a substantially spherical and negatively charged black particle group having an average particle diameter of 9.1 μm.

  The white particles are prepared by dissolving 0.5 parts 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 white particle group was a positively charged spherical white particle group having an average particle diameter of 8.5 μm.

<Verification of water and oil repellency>
A low molecular weight fluorine-based compound represented by the following chemical formula was used as a treating agent. In this chemical formula, R reacts with the metal surface here as R ′ by hydrolysis. Actually, the active ingredient was dissolved in a solvent, the substrate was dipped in the solution and left for 2 hours, and then dipped in the solvent and washed. The resulting thin film layer was not an insulating film because it was formed at the molecular level. Further, there was no concern about drive deterioration or charging during image display.

  According to the above-mentioned treatment, the substrate surface with ITO electrode was treated, and the water repellency with respect to water and the oil repellency with respect to ethylene glycol, jodomethane, and 1 bromonaphthalene were investigated by measuring respective contact angles. FIG. 5 is a graph showing the measurement results of water repellency / oil repellency for a treated product treated on the substrate surface and an untreated product not treated. From the results of FIG. 5, it was found that the treated product provided with the thin film layer in the substrate according to the present invention repels everything from water to oil when treated compared to the untreated product.

<Evaluation of adhesion of image display medium>
Based on the contact angle data described above, between the processed product that has been processed on the substrate surface and the unprocessed product that has not been processed, between the image display medium (here, the black particle group and the white particle group) and the substrate. The interfacial free energy and adhesion work were calculated. Here, the interface free energy, which is the energy for expanding the area of the interface between the substrate and the image display medium, indicates that the higher the contact free energy, the closer the contact is. In addition, the adhesion work, which is a work necessary for peeling off the substrate and the image display medium, indicates that the higher the adhesion work, the harder it is to peel off.

  FIG. 6 is a graph showing the calculation result of the interface free energy for the processed product processed on the substrate surface and the unprocessed product not processed. From the results shown in FIG. 6, the interface free energy, which is the energy for expanding the area of the interface between the substrate and the image display medium, is lower in the treated product than in the untreated product for both the black particle group and the white particle group. It was found that sex decreased. FIG. 7 is a graph showing calculation results of adhesion work on a processed product that has been processed on the substrate surface and an untreated product that has not been processed. From the results shown in FIG. 7, the adhesion work, which is a work necessary for peeling off the substrate and the image display medium, is lower in the treated product than the untreated product in both the black particle group and the white particle group, and may be easily peeled off. Recognize. From the results of FIGS. 6 and 7, it was found that the adhesion of the image display medium can be reduced by processing.

<Reversibility evaluation>
The treated panel and the untreated panel were filled with a black particle group and a white particle group, and the applied voltage was changed to determine the OD value (reflection density) at that time. When the relation between the OD value and the applied voltage was compared for the treated product that had been processed on the substrate surface and the untreated product that had not been treated, the drive voltage was reduced by 10 to 30 V with the same contrast, and the OD was applied with the same applied voltage. It was found that the value was improved by 0.05 to 0.15. The unprocessed product was reversed 10,000 times and the image display medium stopped moving. In addition, the processed product was reversed 20,000 times and the image display medium stopped moving.

  The image display panel according to the present invention includes display units for mobile devices such as notebook computers, PDAs, mobile phones, and handy terminals, electronic papers such as electronic books and electronic newspapers, bulletin boards such as signboards, posters, and blackboards, calculators, and home appliances. It is suitably used for display parts for automobile supplies, card display parts such as point cards and IC cards, electronic advertisements, electronic POPs, electronic price tags, electronic musical scores, and display parts for RF-ID devices.

(A), (b) is a figure which shows operation | movement of an example of the image display panel of this invention, respectively. (A), (b) is a figure which shows operation | movement of the other example of the image display panel of this invention, respectively. (A), (b) is a figure which shows operation | movement of the further another example of the image display panel of this invention, respectively. It is a figure which shows an example of the shape of the partition in the image display panel used as the object of this invention. It is a graph which shows the measurement result about the water repellency and oil repellency with respect to the processed goods which processed the substrate surface, and the untreated goods which were not processed. It is a graph which shows the calculation result of the interface free energy with respect to the processed goods which processed the substrate surface, and the untreated goods which were not processed. It is a graph which shows the calculation result of the adhesion work with respect to the processed goods which processed the substrate surface, and the untreated goods which were not processed.

Explanation of symbols

1, 2 Substrate 3 Image display medium (particle group or powder fluid)
3W White particle group 3B Black particle group 4 Bulkhead 5, 6 Electrode

Claims (6)

  In an image display panel for displaying an image by moving an image display medium by enclosing the image display medium between two substrates transparent at least one and applying an electric field to the image display medium, An image display panel comprising a thin film layer made of a fluorine-based compound having a low molecular weight.   The image display panel according to claim 1, wherein the thin film layer covers at least an electrode surface provided in the substrate.   The image display panel according to claim 1, wherein the thin film layer has a thickness of 0.5 to 500 nm.   The image display panel according to claim 1, wherein the molecular weight of the fluorine-based compound is 50 to 20000.   The image display panel according to claim 1, wherein the image display medium is a particle group or a powder fluid.   The method for manufacturing an image display panel according to any one of claims 1 to 5, wherein a fluorine compound having a low molecular weight is applied in a substrate, and the applied fluorine compound is hydrolyzed to obtain a uniform molecular level. A method for producing an image display panel, characterized in that a film is formed by, and then an excessive fluorine-based compound is washed away.

Images