JP4895528B2 - Information display panel - Google Patents

Description

  The present invention provides at least one or more kinds of optical reflectance and chargeability composed of at least one kind of particles in a cell formed by a partition between two opposing substrates, at least one of which is transparent. The present invention relates to an information display panel that encloses a display medium and applies an electric field to the display medium to move the display medium to display information such as an image.

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

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

  However, the electrophoresis method has a problem that the response speed becomes slow due to the viscous resistance of the liquid because the particles migrate in the liquid. 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, it is difficult to maintain the stability of the dispersed state, and the stability of repeated rewriting of information display is lacking. Have 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 uniformly inject the charge into the conductive particles.

As a method for solving the various problems described above, an optical reflectance composed of at least one kind of particles in a cell formed by a partition between two opposing substrates, at least one of which is transparent. In addition, an information display panel that displays information such as an image by moving the display medium by enclosing at least one display medium having charging properties and applying an electric field to the display medium is known.
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 information display panel described above, the charge amount of the display medium sealed between the panel substrates (in other words, the display medium particles constituting the display medium) is set to be equal to the charge amount of the display medium of the same color. Further, even when two-color display media having different charging polarities are used, the charge amounts of the same color display media are uniform. Therefore, the point in time when the display medium starts to fly between the panel substrates is the same for all the display media, and the voltage applied to the substrates to move the charged display medium sealed between the panel substrates by the electric field is There was a problem of becoming big.

  An object of the present invention is to solve the above-mentioned problems, and an information display panel capable of lowering the driving voltage in consideration of the balance of chargeability of a display medium (colored particles for display medium) filled between panel substrates. Is to provide.

The information display panel of the present invention has an optical reflectance and a charging property composed of at least one kind of particles in a cell formed by a partition between two opposing substrates, at least one of which is transparent. In an information display panel that displays at least one type of display medium and displays information such as an image by moving the display medium by applying an electric field to the display medium, a predetermined charge amount is used as the sealed display medium. A display medium having a charge amount larger than the charge amount of the display medium having a charge amount of 3 to 30% of the display medium having the predetermined charge amount. Thus, the mixture is used.

In addition, as a suitable example of the information display panel of the present invention, when two types of display media are used, the display media may be used for each type, and the display media may be a particle group or a powder fluid.

  According to the information display panel of the present invention, the display medium to be encapsulated is mixed with a display medium having a large charge amount, preferably at a constant rate, without matching the charge amount of the display medium to be encapsulated. When a display is moved by an electric field, first, a display medium with a large charge amount that is easy to fly (move) starts to fly, and other display media with a small charge amount are also those of a display medium with a large charge amount. As the flight starts, the flight (move) occurs together, so that the display medium can reliably fly by applying a voltage lower than that of the prior art. As a result, an information display panel with a low drive voltage can be obtained.

  First, the basic 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 to the display medium sealed between the opposing substrates. Along with the applied electric field direction, the charged display medium is attracted by the electric field force or Coulomb force, etc., and the display medium changes the moving direction by changing the electric field direction by switching the potential, thereby displaying information such as an image. Is made. Therefore, it is necessary to design the information display panel so that the display medium can move uniformly and maintain the rewrite stability of display information or the continuous display stability of display information. 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 the information display panel of the present invention will be described with reference to FIGS. 1 (a) and (b) to FIGS. 3 (a) and 3 (b).

  In the example shown in FIGS. 1A and 1B, at least two types of display media 3 (here, white display consisting of a group of particles) having at least one type of particles and different optical reflectance and charging characteristics. A black display medium 3B composed of a medium 3W and a particle group is enclosed between the substrate 1 and the substrate 2, and the substrates 1 and 2 according to the electric field generated by using some voltage applying means between the substrates. The black display medium 3B is visually recognized by the observer and black display is performed, or the white display medium 3W is visually recognized by the observer and white display is performed. In the example shown in FIG. 1B, the partition walls 4 are formed between the substrates 1 and 2, and a plurality of rectangular cells are provided in a lattice shape. (The partition in front of the figure is omitted.)

  In the example shown in FIGS. 2A and 2B, at least two types of display media 3 (here, 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. 2B, a partition wall 4 is formed between the substrates 1 and 2, and a plurality of quadrangular cells are provided in a lattice shape. (The partition in front of the figure is omitted.)

  In the example shown in FIGS. 3A and 3B, a display medium 3 (here, a white display medium consisting of a group of particles) having one kind of optical reflectance and chargeability composed of at least one kind of particles. 3W) is moved in parallel with the substrates 1 and 2 according to the 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 moved to the observer. The color of the electrode 6 or the substrate 1 (color expressed by an optical reflectivity different from that of the white display medium 3W) is displayed by making the viewer visually recognize the electrode 6 or the substrate 1 Is displayed. In the example shown in FIG. 3B, a partition wall 4 is formed between the substrates 1 and 2, and a plurality of quadrangular cells are provided in a lattice shape. (The partition in front of the figure is omitted.)

  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. I can do it.

  In the information display panel described above, a feature of the present invention is that the display medium (3B or 3W) to be encapsulated has a charge amount larger than the charge amount of the display medium particles having a predetermined charge amount. The point is to use a mixture of particles. When two types of display media (3B or 3W) having different colors and charging characteristics are used, using the display medium (3B or 3W) for each type lowers the driving voltage of the information display panel. Is preferable.

  Further, the mixing amount of the display medium particles having a large charge amount is not particularly limited, but the mixing amount of the display medium particles having a large charge amount is 3 to 30% with respect to the display medium particles having a predetermined charge amount. Preferably there is. Here, if the mixing amount is less than 3%, the effect of mixing particles for a display medium having a large charge amount cannot be sufficiently obtained. If the mixing amount exceeds 30%, the main display medium is charged. It is not clear whether the particles are for display media having a small amount or for display media having a large charge amount, and the effect of lowering the driving voltage of the present invention cannot be sufficiently obtained.

  4 and 5 are diagrams for explaining the mixing amount in the information display panel of the present invention. In the example shown in FIGS. 4 and 5, display medium particles 3-1 with a large charge amount in the center of the display medium (3 </ b> B or 3 W) are particles 3-2 with a slightly small charge amount around them. Think about the impact on In the filled state shown in FIG. 4, assuming that 8 to 24 display medium particles 3-2 around one display medium particle 3-1 are affected, the ratio of the mixing amount is 4 to 13. %. On the other hand, in the filled state shown in FIG. 5, assuming that 6 to 18 display medium particles 3-2 around one display medium particle 3-1 are affected, the ratio of the mixing amount is 6. ~ 17%. In the present invention, the mixing amount thus determined is preferably in the range of 3 to 30%.

  Next, the filling method of the display medium in the information display panel of the present invention will be described below by taking as an example the case of filling two types of white display medium 3W and black display medium 3B.

  FIG. 6 is a view for explaining an example of a filling method of the display medium in the information display panel of the present invention. In the example shown in FIG. 6, first, the charged display medium 3 (here, the black display medium 3B) is supplied from the display medium charge supply device 11 to the display medium support roller 12 (display medium charge support process). At this time, in the present invention, the black display medium 3B to be filled is a mixture of black display medium having a predetermined charge amount and black display medium particles having a charge amount larger than the charge amount.

  Next, a predetermined pattern (for example, a pattern corresponding to the cell pattern of the cells 14 formed by the partition walls 4 on the substrate 1 (or 2) of the panel) is formed on the surface of the photosensitive drum 15 by the electrostatic latent image forming device 13. An electrostatic latent image is formed, and the display medium 3 carried on the surface of the photosensitive drum 15 by the display medium carrying roller 12 is supplied by rotating the display medium carrying roller 12. The display medium 3B is arranged and placed along a predetermined pattern of the latent image (display medium arranging step).

  A conveyance belt 16 that conveys the panel substrate 1 runs under the photosensitive drum 15, and a display medium arranged on the photosensitive drum 15 is disposed on the back side of the conveyance belt 16 that faces the photosensitive drum 15. A transfer device 17 for transferring 3 to the substrate 1 is provided. When the panel substrate 1 conveyed by the conveyance belt 16 passes between the photosensitive drum 15 and the transfer device 17, the display medium 3 arranged and mounted on the photosensitive drum 15 is replaced with the panel substrate 1 (or 2). ) Transferred and filled in the upper cell 14 (display medium transfer filling step).

  As described above, the substrate 1 (or 2) in which the cells 14 are filled with the black display medium 3B is filled with the white display medium 3W so as to overlap the black display medium 3B in the same process. Then, after the display medium filling step for the black display medium 3B and the white display medium 3W is completed, the other substrate 2 is compared to the substrate 1 (or 2) in which the predetermined display medium 3 is filled in the cells 14. An information display panel can be obtained by bonding (or 1) (panel bonding step).

  FIG. 7 is a diagram for explaining another example of the display medium filling method in the information display panel of the present invention. In the example illustrated in FIG. 7, first, the white display medium 3 </ b> W is filled into the cell 14 by the display medium supply device 23 including the nozzle 21 and the container 22. At this time, in the present invention, as the white display medium 3W to be filled, a white display medium having a predetermined charge amount mixed with particles for white display medium having a charge amount larger than the charge amount is used. Next, the substrate 1 (or 2) filled with the white display medium 3W in the cell 14 is filled with the black display medium 3B so as to overlap the white display medium 3W in the same process. Then, after the display medium filling step for the white display medium 3W and the black display medium 3B is completed, the other substrate 2 with respect to the substrate 1 (or 2) in which the predetermined display medium 3 is filled in the cell 14. By attaching (or 1), an information display panel can be obtained.

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

  As for the substrate, at least one substrate is the transparent substrate 2 from which the color of the display medium 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 substrate 1 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.

  Electrode forming materials for providing electrodes on information display panels include metals such as aluminum, silver, nickel, copper, and gold, and conductive metal oxides such as ITO, indium oxide, conductive tin oxide, and conductive zinc oxide. , Conductive polymers such as polyaniline, polypyrrole, and polythiophene are exemplified and 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. The method of apply | coating is used. The electrode provided on the display surface side substrate 2 which is on the viewing side and needs to be transparent needs to be transparent, but the electrode provided on the back side substrate 1 does not need to be transparent. In any case, the above-mentioned material that can be patterned and is electrically conductive can be suitably 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 1 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 height and width of the partition provided on the substrate are appropriately set according to the type of display medium involved in display, and are not generally limited. However, the partition width is 2 to 100 μm, preferably 3 to 50 μm, and the height of the partition is 10 It is adjusted to ˜500 μm, preferably 10 to 200 μm. The cell shape in the information display panel obtained by superimposing the display side substrate and the back side substrate may be various shapes as illustrated in FIG. It is better to make the portion corresponding to the partition cross section visible from the display surface side (the area of the cell frame formed by the partition width) as small as possible, and the display state becomes clearer.

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

  The “powder fluid” in the present invention is a substance in an intermediate state of both fluid and particle characteristics that exhibits fluidity by itself without borrowing the force of gas or liquid. For example, liquid crystal is defined as an intermediate phase between a liquid and a solid, and has fluidity that is a characteristic of liquid and anisotropy (optical properties) that is a characteristic of solid (Heibonsha: Encyclopedia) . On the other hand, the definition of particle is an object with a finite mass even if it is negligible, and is said to be affected by gravity (Maruzen: Physics Encyclopedia). Here, even in the case of particles, there are special states of gas-solid fluidized bed and liquid-solid fluids. When gas is flowed from the bottom plate to the particles, upward force is applied to the particles according to the velocity of the gas. Is a gas-solid fluidized bed that is in a state where it can easily flow when it balances with gravity, and it is also called a liquid-solid fluidized state that is fluidized by a fluid (ordinary) Company: Encyclopedia). As described above, the gas-solid fluidized bed body and the liquid-solid fluid are in a state of using a gas or liquid flow. In the present invention, it has been found that a substance in a state of fluidity can be produced specifically without borrowing the force of such gas and liquid, and this is defined as powder fluid.

  That is, the pulverulent fluid in the present invention is in an intermediate state having both the characteristics of particles and liquid, as in the definition of liquid crystal (liquid and solid intermediate phase), and is the characteristic of the above-mentioned particles. It is a substance that is extremely unaffected and exhibits a unique state with high fluidity. Such a substance can be obtained in an aerosol state, that is, in a dispersion system in which a solid or liquid substance is stably suspended as a dispersoid in a gas, and the solid substance is regarded as a dispersoid in the information display panel of the present invention. To do.

The information display panel of the present invention encloses a powder fluid exhibiting high fluidity in an aerosol state in which solid particles are stably suspended as a dispersoid, for example, in a gas between opposing substrates, at least one of which is transparent. Yes, such a powder fluid can be easily and stably moved by a Coulomb force 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, it is used as a display medium in a state where a solid substance floats relatively stably as a dispersoid in the gas.

Next, display medium particles (hereinafter also referred to as particles) constituting the display medium in the information display panel of the present invention will be described. The display medium particles are composed of the display medium particles as they are to form a display medium, or are combined with other particles to form a display medium, or adjusted and configured to become a powder fluid to form a display medium. Or used.
The particles can contain a charge control agent, a colorant, an inorganic additive, and the like, if necessary, in the resin as the main component, as in the conventional case. Examples of resins, charge control agents, colorants, and other additives will be given below.

  Examples of the resin include urethane resin, urea resin, acrylic resin, polyester resin, acrylic urethane resin, acrylic urethane silicone resin, acrylic urethane fluororesin, acrylic fluororesin, silicone resin, acrylic silicone resin, epoxy resin, polystyrene resin, styrene Acrylic resin, polyolefin resin, butyral resin, vinylidene chloride resin, melamine resin, phenol resin, fluororesin, polycarbonate resin, polysulfone resin, polyether resin, polyamide resin and the like can be mentioned, and two or more kinds can be mixed. In particular, acrylic urethane resin, acrylic silicone resin, acrylic fluororesin, acrylic urethane silicone resin, acrylic urethane fluororesin, fluororesin, and silicone resin are suitable from the viewpoint of controlling the adhesive force with the substrate.

  The charge control agent is not particularly limited. Examples of the negative charge control agent include salicylic acid metal complexes, metal-containing azo dyes, metal-containing oil-soluble dyes (including metal ions and metal atoms), and quaternary ammonium salt systems. Examples thereof include compounds, calixarene compounds, boron-containing compounds (benzyl acid boron complexes), and nitroimidazole derivatives. Examples of the positive charge control agent include nigrosine dyes, triphenylmethane compounds, quaternary ammonium salt compounds, polyamine resins, imidazole derivatives, and the like. In addition, metal oxides such as ultrafine silica, ultrafine titanium oxide, ultrafine alumina, nitrogen-containing cyclic compounds such as pyridine and derivatives and salts thereof, various organic pigments, resins containing fluorine, chlorine, nitrogen, etc. are also charged. It can also be used as a control agent.

  As the colorant, various organic or inorganic pigments and dyes as exemplified below can be used.

Examples of the black colorant include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon and the like.
Examples of blue colorants include C.I. I. Pigment blue 15: 3, C.I. I. Pigment Blue 15, Bituminous Blue, Cobalt Blue, Alkaline Blue Lake, Victoria Blue Lake, Phthalocyanine Blue, Metal-free Phthalocyanine Blue, Phthalocyanine Blue Partial Chlorides, Fast Sky Blue, Indanthrene Blue BC and the like.
Examples of red colorants include bengara, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, 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 yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, Indanthrene Brilliant Orange RK, Benzidine Orange G, Indanthren 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.

As extender pigments, barite powder, barium carbonate, clay, silica, white carbon,
There are 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 the display medium can be moved uniformly.

  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 inventors of the present invention have been able to evaluate the range of proper charging characteristics of display medium particles by measuring the charge amount of display medium particles using the same carrier particles in the blow-off method. I found it.

Furthermore, when the present invention is used for a dry information display panel, it is important to manage the gas in the gap surrounding the display medium, which contributes to improved display stability. 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 by the electrodes 5 and 6 (the electrodes are placed on the inside of the substrate). Gas portion in contact with the so-called display medium, excluding the occupied portion of the display medium 3 (particle group or powdered fluid), the occupied portion of the partition wall 4 (when the partition wall is provided), 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.
In the case of a dry information display panel, the volume occupancy 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 specifically described with reference to examples and comparative examples of the present invention, but the present invention is not limited to the following.

"Preparation of display media"
The display media used in the examples and comparative examples are the following four types of particles for black and white display medium particles having different charging characteristics (particle group A, particle group B, particle group C, particle group D). Was used.

Particle group A consists of acrylic urethane resin EAU53B (manufactured by Asia Industry Co., Ltd.) / IPDI crosslinking 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 E89 (made by Orient Chemical Co., Ltd.) are added, kneaded, pulverized by a jet mill, and further mechanical impact force is applied using a hybridizer device (made by Nara Machinery Co., Ltd.). In addition, classification was made after making it approximately spherical. The produced particle group A was a substantially spherical and negatively charged black particle group having an average particle diameter of 9.1 μm and a charge amount of −10 μC / g.
Particle group C was produced in the same manner as particle group A except that 5 parts by weight of charge control agent Bontron E89 (manufactured by Orient Chemical Co., Ltd.) was added to particle group A. The produced particle group C was a substantially spherical, negatively charged black particle group having an average particle diameter of 9.0 μm and a charge amount of −20 μC / g.

Particle group B was 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 particle group B was a spherical white particle group having an average particle diameter of 8.5 μm and a charge amount of +10 μC / g and positively chargeable.
Particle group D was prepared in the same manner as particle group C, except that 2 parts by weight of charge control agent Bontron N07 (manufactured by Orient Chemical Co., Ltd.) was added to particle group C. The produced particle group D was a spherical white particle group having an average particle diameter of 8.2 μm and a charge amount of +17 μC / g and positively charged.

"Production of panel substrate"
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 (7 cm × 7 cm □) with an ITO electrode was prepared.

<Example 1>
As a black display medium, a particle group A mixed with a small amount of particle group C (the mixing ratio of the particle group C was 3 wt%) was prepared. Next, a white display medium prepared by mixing a small amount of the particle group D with the particle group B (the mixing ratio of the particle group D was 3% by weight) was prepared.
The prepared black display medium and white display medium were continuously filled in the cells of one substrate on which the partition walls were formed by the display medium filling step shown in FIG. The filling arrangement amount of the black display medium and the white display medium was the same volume amount, and the volume occupancy ratio of both display media with respect to the space between the substrates formed by bonding the two substrates was adjusted to 25 vol%.

Next, the other substrate is overlapped with the substrate in which the display medium is filled and arranged in the cell, the outer peripheral portion around the substrate is adhered and sealed with an epoxy adhesive, and the display medium is sealed, for information display A panel was produced.
The produced information display panel was incorporated in a driving device, and white display and black display were rewritten by applying a voltage from the driving device to the ITO electrode on the substrate. First, the display rewriting was performed 100 times by applying a 250 V voltage, and then the voltage was gradually increased and the voltage at which the next display rewriting occurred was obtained as the driving voltage.

<Example 2>
A black display medium prepared by mixing a small amount of the particle group C with the particle group A (mixing ratio of the particle group C is set to 30% by weight) is prepared, and a small amount of the particle group D is added to the particle group B as a white display medium. An information display panel was prepared in the same procedure as in Example 1 except that a mixture of particles (the mixing ratio of the particle group D was set to 30% by weight) was prepared, and the manufactured information display panel was incorporated into the driving device. The driving voltage was determined.

<Example 3>
A black display medium prepared by mixing a small amount of the particle group C with the particle group A (mixing ratio of the particle group C is set to 30% by weight) is prepared, and a small amount of the particle group D is added to the particle group B as a white display medium. An information display panel was prepared in the same procedure as in Example 1 except that a mixture of particles (the mixing ratio of the particle group D was set to 3% by weight) was prepared, and the manufactured information display panel was incorporated into the driving device. The driving voltage was determined.

<Example 4>
A black display medium prepared by mixing a small amount of the particle group C with the particle group A (the mixing ratio of the particle group C is 3% by weight) is prepared, and a small amount of the particle group D is added to the particle group B as a white display medium. An information display panel was prepared in the same procedure as in Example 1 except that a mixture of particles (the mixing ratio of the particle group D was set to 30% by weight) was prepared, and the manufactured information display panel was incorporated into the driving device. The driving voltage was determined.

<Comparative Example 1>
A black display medium prepared by mixing a large amount of the particle group C with the particle group A (the mixing ratio of the particle group C is 40% by weight) is prepared, and a large amount of the particle group D is added to the particle group B as a white display medium. An information display panel was produced in the same procedure as in Example 1 except that a mixture of particles (the mixing ratio of the particle group D was 40% by weight) was prepared, and the produced information display panel was incorporated into the drive device. The driving voltage was determined.

<Comparative example 2>
A black display medium prepared by mixing a small amount of the particle group C with the particle group A (the mixing ratio of the particle group C is 1% by weight) is prepared, and a small amount of the particle group D is added to the particle group B as a white display medium. An information display panel was prepared in the same procedure as in Example 1 except that a mixture of particles (the mixing ratio of the particle group D was set to 1% by weight) was prepared, and the manufactured information display panel was incorporated into the driving device. The driving voltage was determined.

  The results are shown in Table 1.

  From the results in Table 1, the mixing ratio of the highly charged display medium particles in the black display medium is in the range of 3 to 30% by weight, and the mixing ratio of the highly charged display medium particles in the white display medium is 3 to 30% by weight. In the first to fourth embodiments in which the information display panel using the two-color display medium in the range of% is displayed and driven, the driving voltage is in the range of 70 to 85 V and can be driven at a low voltage. An information display panel using a display medium of two colors in which the mixing ratio of the highly charged display medium particles in the medium and the mixing ratio of the highly charged display medium particles in the white display medium is not in the range of 3 to 30% by weight is displayed. In Comparative Examples 1 and 2 that were driven, the driving voltage was in the range of 125 to 150 V, and it was found that driving at a low voltage could not be performed.

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

(A), (b) is a figure which shows the structure of an example of the information display panel of this invention, respectively. (A), (b) is a figure which shows the structure of the other example of the information display panel of this invention, respectively. (A), (b) is a figure which shows the structure of the further another example of the information display panel of this invention, respectively. It is a figure for demonstrating an example of the mixing amount in the information display panel of this invention. It is a figure for demonstrating the other example of the mixing amount in the information display panel of this invention. It is a figure for demonstrating an example of the filling method of the display medium in the information display panel of this invention. It is a figure for demonstrating the other example of the filling method of the display medium in 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 used as the object of the manufacturing method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Substrate 3 Display medium 3W White display medium 3B Black display medium 4 Bulkhead 5, 6 Electrode 11 Display medium charge supply device 12 Display medium carrying roller 13 Electrostatic latent image forming device 14 Cell 15 Photosensitive drum 16 Conveying belt 17 Transfer apparatus

Claims (3)

At least one type of display medium having optical reflectivity and chargeability composed of at least one type of particles is enclosed in a cell formed by a partition between two opposing substrates, at least one of which is transparent. In an information display panel that displays information such as images by moving the display medium by applying an electric field to the display medium, the charge amount is applied to a display medium having a predetermined charge amount as a display medium to be enclosed. A display medium having a larger charge amount than the display medium having a predetermined charge amount mixed with a display medium having a larger charge amount is 3 to 30%. An information display panel characterized by 2. The information display panel according to claim 1, wherein when two types of display media are used, the display media are used for each type. The information display panel according to claim 1, wherein the display medium is a particle group or a powder fluid.

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