JP2007310136A - Method for arranging display medium in panel for information display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for charging a display medium (particles) and spraying and arranging it from a nozzle between substrates of a display panel so as to make the application of a large electric field for initial driving of a completed panel for display unnecessary. <P>SOLUTION: In the panel for information display, with which information such as an image etc. is displayed by arranging the display medium between two substrates of which at least one is transparent and making the display medium move by applying an electric field to it, carrier particles are added to colored particles for display, to construct the display medium before arrangement, the particles for display are charged by the mutual friction, and the particles for the display medium to be sprayed are sprayed and arranged, after they have been charged to saturation. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is used for an information display panel that displays information such as an image by moving a display medium by enclosing a display medium between two substrates, at least one of which is transparent, and applying an electric field to the display medium. The present invention relates to a method of arranging a display medium.

  2. Description of the Related Art In recent years, an image display panel has been proposed as an information display device that replaces a liquid crystal (LCD), which is dry, has a quick response performance, has a simple structure, is inexpensive, and has excellent stability. In this image display panel, two or more kinds of particles having different colors and charging characteristics are enclosed between two substrates, and a voltage is applied between the substrates to apply an electrostatic field to the particles to move the particles. An image is displayed (see, for example, Patent Document 1).

  In the above prior art, when the particles constituting the display medium are filled in a plurality of cells provided by the partition walls on the substrate, the substrate is provided with a nozzle in the upper part of the container and provided with the partition wall in the lower part By spraying the particles dispersed in the gas from the nozzle and filling the cells into the cells on the substrate placed in the lower part of the container, the particles are uniformly and evenly enclosed in multiple cells (For example, see Patent Document 2).

  When encapsulating two or more kinds of particles having different colors and charging characteristics, first, the first particles dispersed in the gas are sprayed from a nozzle provided in the upper part of the container to place the lower part of the container. After filling the cells on the substrate, the substrate filled with the first particles is placed in the lower part of the container, and the second particles are dispersed in the gas from the nozzle provided above the container. By spraying the particles, the first particles already filled in the cells on the substrate are overlaid and filled, and then the above steps are repeated sequentially to fill all the particles in the cells.

After that, after the particles are packed and arranged on the substrate provided with the partition walls, the other substrate is overlapped to enclose the particles in the cells between the substrates, thereby manufacturing the image display panel.
International Publication No. 03/050606 Pamphlet International Publication No. 2004/055586 Pamphlet

  When the particles (positively charged colored particles or negatively charged colored particles) constituting the display medium are arranged between the panel substrates on the information display panel described above, the particles to be dispersed are transported from the container to the spray nozzle. It is charged by friction with the piping wall in the process, and is placed between the nozzle and the display panel substrate as a charged display medium (particles). It was necessary to apply a large electric field for the initial drive of the display panel.

  An object of the present invention is to provide a method of charging a display medium (particle) between nozzles and a display panel substrate so that it is not necessary to apply a large electric field to the initial drive of a completed display panel. It is something to try.

  In the information display panel according to the present invention, the display medium is arranged by adding carrier particles to the display colored particles constituting the display medium before arrangement and frictionally charging each other to saturate the display colored particles before arrangement. It is characterized by being sprayed and arranged after being allowed to.

  Further, as a preferred example of the method of arranging the display medium in the information display panel of the present invention, a spray nozzle having a mesh of openings larger than the particle diameter of the display medium to be sprayed and smaller than the particle diameter of the carrier particles. Is used to remove the mixed carrier particles so that only colored particles for display are scattered.

  According to the present invention, a carrier particle is added to the colored particles for display before arrangement, and they are triboelectrically charged to each other, and the colored particles for display before arrangement are saturated and charged, and then dispersed and arranged. Therefore, it is not necessary to apply a large electric field to the initial driving of the panel. In addition, when using a spray nozzle having an opening mesh that is larger than the particle diameter of the display medium to be dispersed and smaller than the particle diameter of the carrier particles, the mixed carrier particles are removed, and the display colored particles Only can be sprayed.

  First, the basic configuration of the information display panel of the present invention will be described. In the information display panel which is an object of the present invention, an electric field is applied to a display medium sealed between two opposing substrates. In accordance with the applied electric field direction, the charged display medium is attracted by the electric field force or the Coulomb force, and the display medium changes the moving direction according to the change of the electric field direction, thereby displaying information such as an image. Therefore, it is necessary to design the information display panel so that the display medium can move uniformly and maintain stability when rewriting the display repeatedly or when displaying the display information continuously. Here, as the force applied to the particles constituting the display medium, in addition to the force attracting each other by the Coulomb force between the particles, an electric mirror image force between the electrode and the substrate, an intermolecular force, a liquid cross-linking force, gravity and the like can be considered.

  An example of an information display panel that 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, at least two kinds of display media 3 (here, white display medium particles 3Wa) having at least one kind of particles and having different optical reflectance and charging characteristics. A white display medium 3W composed of a group of particles and a black display medium 3B composed of a group of particles 3Ba for black display medium) are perpendicular to the substrates 1 and 2 according to the electric field applied from the outside of the substrates 1 and 2. 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, in addition to the example shown in FIG. 1A, a partition 4 is provided between the substrates 1 and 2, for example, in the form of a lattice to form a cell. In addition, in FIG. 1B, the partition in front is omitted. The electrode may be provided outside the substrate or may be provided so as to be embedded inside the substrate.

  In the example shown in FIGS. 2A and 2B, at least two or more types of display media 3 (here, white display medium particles 3Wa) having different optical reflectance and charging characteristics composed of at least one type of particles. Between the electrode 5 provided on the substrate 1 and the electrode 6 provided on the substrate 2 is a voltage between the electrode 5 provided on the substrate 1 and the electrode 6 provided on the substrate 2. In accordance with the electric field generated by applying, the substrate is moved perpendicularly to the substrates 1 and 2 so that the black display medium 3B is visually recognized by the observer and black display is performed, or the white display medium 3W is provided to the observer. A white display is made by visual recognition. In the example shown in FIG. 2B, a cell is formed by providing partition walls 4 between the substrates 1 and 2, for example, in a lattice shape. Further, in FIG. 2 (b), the front partition is omitted. The electrode may be provided outside the substrate or may be provided so as to be embedded inside the substrate.

  In the example shown in FIGS. 3A and 3B, the display medium 3 (here, from the particle group of the particles 3Wa for white display medium) having at least an optical reflectance and a charging property composed of at least one kind of particles. The white display medium 3W) is moved in a direction parallel to the substrates 1 and 2 in accordance with the electric field generated by applying a voltage between the electrode 5 and the electrode 6 provided on the substrate 1 to display white. The medium 3W is visually recognized by the observer and white display is performed, or the color of the electrode 6 or the substrate 1 is visually recognized by the observer and the color of the electrode 6 or the substrate 1 is displayed. In the example shown in FIG. 3B, for example, a lattice-shaped partition wall 4 is provided between the substrates 1 and 2 to form a cell. Moreover, in FIG.3 (b), the partition in front is abbreviate | omitted. The electrode may be provided outside the substrate or may be provided so as to be embedded inside the substrate.

  FIG. 4 shows a first embodiment in which particles are dispersed and arranged by the method of the present invention. The colored particles for display 11a and the carrier particles 12 are mixed and added to the spraying device 20a, and the colored particles for display 11a are sprayed after friction charging with each other. For the display colored particles 11a to be charged positively, the carrier particles 12 that easily charge the display colored particles 11a are selected, and for the display colored particles 11a to be negatively charged, the display colored particles 11a are selected. Carrier particles 12 that easily charge 11a negatively are selected. A stirring rotor 13a is attached to the spraying device 20a, and the colored particles for display 11a and the carrier particles 12 are rubbed to sufficiently charge the colored particles for display 11a. The colored particles for display 11a and the carrier particles 12 sent to the transport pipe 14 are sufficiently charged with opposite polarities, and even if there is friction with the pipe wall of the transport pipe 14, the charged amount (saturation) It is conveyed to the portion of the spray nozzle 15 in the vicinity of the outlet of the spraying device 20a while maintaining the (charge amount).

  A mesh (mesh) 16 having an opening larger than the particle diameter of the display colored particles 11a to be dispersed and smaller than the particle diameter of the carrier particles 12 is stretched at the outlet portion of the spray nozzle 15, and the display colored particles. Only 11a is sprayed from the spray nozzle 15. The charged colored particles for display 11b that have passed through the mesh 16 are arranged on the panel.

  Examples of carrier particles 12 include Cu-Zn ferrite particles (with resin coating and no resin coating), Mn-Mg-Sr ferrite particles (with resin coating and no resin coating), Mn ferrite particles (resin With coating, without resin coating), Li-Mg-Ca ferrite particles (with resin coating, without resin coating), and the like. As these ferrite carrier particles, those commercially available as an electrophotographic toner carrier can be used. For example, toner carrier for electrophotography (for example, TEFV200 / 300, F-300, EF-60B, MF-50, EF-60A, EF96-40B, etc.) manufactured by Powder Tech Corporation, Dowa, etc. An electrophotographic toner carrier (for example, DFC-100, DFC-100 WLINKLE, etc.) manufactured by Iron Powder Industry Co., Ltd. (DOWA IRON POWDER CO., LTD) can be used. As the carrier particles 12, carrier particles having a particle diameter larger than the particle diameter of the colored particles for display 11a arranged in the information display panel are used from a particle diameter of 15 to 150 μm.

  FIG. 5 shows a second embodiment in which particles are dispersed and arranged by the method of the present invention. The stirring rotor 13a attached to the spraying device 20a in the first embodiment has a blade shape, and the stirring rotor 13b attached to the spraying device 20b in the second embodiment has a disk shape with an uneven surface. In the example shown in FIG. 5, the same members as those in the example shown in FIG.

  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, polyethylene naphthalate, polyethersulfone, polyethylene, polycarbonate, polyimide, and acrylic, flexible materials such as metal sheets, and glass and quartz. An inorganic sheet having no flexibility is mentioned. The thickness of the substrate is preferably from 2 to 5000 μm, more preferably from 5 to 2000 μm. If it is too thin, it will be difficult to maintain the strength and the spacing uniformity between the substrates, and if it is thicker than 5000 μm, it will be a thin information display panel. Is inconvenient.

  As an electrode forming material when an electrode is provided on an information display panel as required, metals such as aluminum, silver, nickel, copper, and gold, indium tin oxide (ITO), indium oxide, antimony metal oxide (ATO) ), Conductive metal oxides such as conductive tin oxide and conductive zinc oxide, and conductive polymers such as polyaniline, polypyrrole and polythiophene are exemplified and used as appropriate. 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 shape of the partition walls 4 provided on the substrate as required is appropriately set appropriately depending on the type of display medium involved in display, the shape and arrangement of electrodes to be arranged, and is not limited in general. The height of the partition is adjusted to 100 to 100 μm, preferably 3 to 50 μm, and the height of the partition wall to 10 to 100 μm, preferably 10 to 50 μm.
In forming the partition wall, a both-rib method in which ribs are formed on each of the opposing substrates 1 and 2 and then bonded, and a single-rib method in which ribs are formed only on one substrate are conceivable. In the present invention, any method is preferably used.
As shown in FIG. 6, the cells formed by the partition walls made up of these ribs are exemplified by a square shape, a triangular shape, a line shape, a circular shape, and a hexagonal shape as viewed from the plane of the substrate. And a mesh shape. It is better to make the portion corresponding to the cross section of the partition wall visible from the display surface side (the area of the cell frame) as small as possible, and the display becomes clearer.
Examples of the method for forming the partition include a mold transfer method, a screen printing method, a sand blast method, a photolithography method, and an additive method. Any of these methods can be suitably used for the information display panel of the present invention, and among these, a photolithography method using a resist film and a mold transfer method are suitably used.

Next, the display colored particles (hereinafter also referred to as particles) constituting the display medium in the information display panel of the present invention will be described. The colored particles for display are used as they are as a display medium by being composed of the colored particles for display as they are, or by being combined with other particles as a display medium.
The particles can contain a charge control agent, a colorant, an inorganic additive, and the like, as necessary, in the resin as the main component, as necessary. 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 (CCA) is not particularly limited, but 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), quaternary Ammonium salt compounds, calixarene compounds, boron-containing compounds (benzyl acid boron complexes), nitroimidazole derivatives and the like can be mentioned. Examples of the positive charge control agent include nigrosine dyes, triphenylmethane compounds, quaternary ammonium salt compounds, polyamine resins, imidazole derivatives, and the like. In addition, metal oxides such as ultrafine silica, ultrafine titanium oxide, ultrafine alumina, nitrogen-containing cyclic compounds such as pyridine and derivatives and salts thereof, various organic pigments, resins containing fluorine, chlorine, nitrogen, etc. are also charged. It can also be used as a control agent.

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

Examples of the black colorant include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon and the like.
Examples of blue colorants include C.I. I. Pigment blue 15: 3, C.I. I. Pigment Blue 15, Bituminous Blue, Cobalt Blue, Alkaline Blue Lake, Victoria Blue Lake, Phthalocyanine Blue, Metal-free Phthalocyanine Blue, Phthalocyanine Blue Partial Chlorides, Fast Sky Blue, Indanthrene Blue BC, and the like.
Examples of red colorants include bengara, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, risor red, pyrazolone red, watching red, calcium salt, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, Alizarin Lake, Brilliant Carmine 3B, C.I. I. Pigment Red 2 etc.

Yellow colorants include chrome yellow, zinc yellow, cadmium yellow, yellow iron oxide, mineral first yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa Yellow G, Hansa Yellow 10G, Benzidine Yellow G, Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake, C.I. I. Pigment Yellow 12 etc.
Examples of green colorants include chrome green, chromium oxide, pigment green B, C.I. I. Pigment Green 7, Malachite Green Lake, Final Yellow Green G, etc.
Examples of the orange colorant include red chrome yellow, molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, indanthrene brilliant orange RK, benzidine orange G, indanthrene brilliant orange GK, C.I. I. Pigment Orange 31 etc.
Examples of purple colorants include manganese purple, first violet B, and methyl violet lake.
Examples of white colorants include zinc white, titanium oxide, antimony white, and zinc sulfide.

  Examples of extender pigments include barite powder, barium carbonate, clay, silica, white carbon, talc, and alumina white. Examples of various dyes such as basic, acidic, disperse, and direct dyes include nigrosine, methylene blue, rose bengal, quinoline yellow, and ultramarine blue.

Examples of inorganic additives include titanium oxide, zinc white, zinc sulfide, antimony oxide, calcium carbonate, lead white, talc, silica, calcium silicate, alumina white, cadmium yellow, cadmium red, cadmium orange, titanium yellow, Examples include bitumen, ultramarine blue, cobalt blue, cobalt green, cobalt violet, iron oxide, carbon black, manganese ferrite black, cobalt ferrite black, copper powder, and aluminum powder.
These pigments and inorganic additives can be used alone or in combination. Of these, carbon black is particularly preferable as the black pigment, and titanium oxide is preferable as the white pigment. Colored particles for display having a desired color can be produced by blending the colorant.

  The colored particles for display (hereinafter also referred to as “particles”) of the present invention have an average particle diameter d (0.5) in the range of 0.1 to 20 μm and are preferably uniform. If the average particle diameter d (0.5) is larger than this range, the display is not clear. If the average particle diameter d (0.5) is smaller than this range, the cohesive force between the particles becomes too large, which hinders movement as a display medium.

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

  Furthermore, regarding the correlation between the particles, the ratio of the d (0.5) of the particles having the minimum diameter to the d (0.5) of the particles having the maximum diameter among the used particles is set to 50 or less, preferably 10 or less. It is essential. Even if the particle size distribution Span is reduced, particles with different charging characteristics move in opposite directions, so that the particle size is close to each other and each particle can be easily moved in the opposite direction by the equivalent amount. This is within this range.

The particle size distribution and the particle size can be obtained from a laser diffraction / scattering method or the like. When laser light is irradiated onto particles to be measured, a light intensity distribution pattern of diffracted / scattered light is spatially generated, and this light intensity pattern has a corresponding relationship with the particle diameter, so that the particle diameter and particle diameter distribution can be measured. .
Here, the particle size and particle size distribution in the present invention are obtained from a volume-based distribution. Specifically, using a Mastersizer2000 (Malvern Instruments Ltd.) measuring instrument, put particles into a nitrogen stream and use the attached analysis software (software based on volume-based distribution using Mie theory). The diameter and particle size distribution can be measured.

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

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

Furthermore, when a display medium composed of colored particles for display is applied to a dry information display panel that is driven in the air space, it is important to manage the gas in the void surrounding the display medium between the substrates. Contributes to improved stability. Specifically, it is important that the relative humidity at 25 ° C. is 60% RH or less, and preferably 50% RH or less for the humidity of the gas in the gap.
1A, 1B, 3B, 3B, and 3B, the gaps are defined as electrodes 5 and 6 (electrodes on the inner side of the substrate). 2), the occupied portion of the display medium 3, the occupied portion of the partition wall 4 (when the partition wall is provided), and the gas portion in contact with the so-called display medium, excluding the seal portion of the information display panel.
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 in a predetermined humidity environment, It is important to apply a sealing material and a sealing method that prevent moisture from entering from the outside.

The distance between the substrates in the information display panel that is the subject of the present invention is not limited as long as the display medium can be moved and the contrast can be maintained, but is usually adjusted to 10 to 500 μm, preferably 10 to 200 μm.
The volume occupation ratio of the display medium disposed in the space between the opposing substrates is preferably 5 to 70%, more preferably 5 to 60%. If it exceeds 70%, the movement of the display medium is hindered, and if it is less than 5%, the contrast tends to be unclear.

  The information display panel manufactured by using the information medium arranging method in the information display panel of the present invention is a display unit of a mobile device such as a notebook computer, PDA, mobile phone, handy terminal, electronic book, electronic newspaper, etc. Electronic paper, signboards, posters, bulletin boards such as blackboards, calculators, home appliances, display parts for automobiles, card displays such as point cards, IC cards, electronic advertisements, information boards, electronic POPs (Point Of Presence, Point Of Purchase advertising), electronic price tag, electronic shelf label, electronic score, display unit of RF-ID equipment, etc.

(A), (b) is a figure which shows an example of the information display panel used as the object of the display medium arrangement | positioning method of this invention, respectively. (A), (b) is a figure which shows the other example of the information display panel used as the object of the arrangement | positioning method of the display medium of this invention, respectively. (A), (b) is a figure which shows the further another example of the information display panel used as the object of the arrangement | positioning method of the display medium of this invention, respectively. 1 shows a first embodiment in which particles are dispersed and arranged according to the present invention. 3 shows a second embodiment in which particles are dispersed and arranged according to the present 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 display medium arrangement | positioning method of this invention.

Explanation of symbols

1, 2 Substrate 3 Display medium 3 W White display medium 3 Wa Display white particle 3 B Black display medium 3 Ba Display black particle 4 Partition 5, 6 Electrode 11 a Display colored particle 11 b Charged display colored particle 12 Carrier particle 13 a, 13 b Stirring Rotor 14 Transport piping 15 Spray nozzle 16 Mesh
20a, 20b Spraying device

Claims (2)

  In an information display panel that displays information such as images by moving a display medium by disposing a display medium between two substrates transparent at least one and applying an electric field to the display medium It is characterized by adding carrier particles to display colored particles constituting the medium in advance, frictionally charging each other, charging the display colored particles before arrangement, and then dispersing and arranging only the charged display colored particles. For disposing a display medium in an information display panel.   The method according to claim 1, wherein the carrier is mixed by using a spray nozzle having a mesh of openings larger than the particle diameter of the colored particles for display to be dispersed and smaller than the particle diameter of the carrier particles. A method of arranging a display medium in an information display panel, wherein particles are removed and only the display medium is dispersed.

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