JP2006126270A - Panel for information display, and information display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a panel for information display in which an opening ratio is heightened, while retaining display quality by thinning out partition walls located, in a direction which does not contribute to the dispersion of a display medium, and an information display device. <P>SOLUTION: In the information display device with the panel for information display to display information, such as images by forming a plurality of cells partitioned with the partition walls 4 between two sheets of substrates 1, 2, of which at least one is transparent and which are placed opposite to each other; sealing at least one or more kinds of display mediums 3W, 3B comprising at least one or more kinds of particles in the cells; and transferring the display mediums by the electric field generated between the substrates, mounted thereon, improving of the aperture ratio and superior display quality are made compatible with each other, by thinning out the partition walls, parallel to the display surface side electrode 5 among the partition walls 4 arranged to partition and form the cells at predetermined spacings (in this case, alternately). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  In the present invention, a plurality of cells partitioned by partition walls are formed between two opposing substrates, at least one of which is transparent, and at least one kind of display composed of at least one kind of particles in the cell. The present invention relates to an information display panel and an information display device for displaying information by enclosing a medium and moving the display medium by an electric field generated in a substrate.

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

  Compared to LCDs, these conventional technologies have advantages such as a wide viewing angle close to that of ordinary printed materials, low power consumption, and a memory function. It is considered as a technology that can be used for mobile phones, and is expected to expand to information display for mobile terminals, electronic paper, and the like. In particular, recently, an electrophoretic method (for example, see Non-Patent Document 1) in which a dispersion liquid composed of dispersion particles and a colored solution is microencapsulated and disposed between opposing substrates has been proposed and expected. It has been.

  However, the electrophoresis method has a problem that the response speed becomes slow due to the viscous resistance of the liquid because the particles migrate in the liquid. In addition, since particles with high specific gravity such as titanium oxide are dispersed in a solution with low specific gravity, it is easy to settle, and it is difficult to maintain the stability of the dispersed state, and there is a problem that the stability of repeated information display is lacking. ing. Even when microencapsulation is performed, the cell size is set to the microcapsule level, and the above-described drawbacks are hardly made to appear, and the essential problems are not solved at all.

  On the other hand, a method in which conductive particles and a charge transport layer are incorporated into a part of a substrate without using a solution is proposed instead of an electrophoresis method using behavior in a solution (see, for example, Non-Patent Document 1). ). However, this method has a problem that the structure is complicated because the charge transport layer and further the charge generation layer are arranged, and that it is difficult to inject the charges into the conductive particles, so that the stability is lacking. .

As one method for solving the various problems described above, a plurality of cells partitioned by partition walls are formed between two opposing substrates, at least one of which is transparent, and at least one kind of particles are formed in the cells. There is known an information display device that displays at least one type of display medium composed of the above and displays information by moving the display medium by an electric field generated in a substrate. In such an information display device, a gap between two opposing substrates is held by a partition wall (spacer), and the display medium is prevented from moving in the horizontal direction with respect to the display surface by being finely divided by the partition wall. In addition, when performing dot matrix display, a structure is adopted in which each pixel is surrounded by a partition arranged in a matrix, and the aperture ratio of the information display device is limited by this partition, but the line width of the partition is narrowed. By doing so, the aperture ratio can be improved.
However, if the line width of the partition wall is too narrow, problems such as a decrease in strength and difficulty in forming the partition wall occur. As a countermeasure, it is conceivable to form a structure in which a plurality of pixels (for example, 2 × 2 pixels) are surrounded by the partition walls by reducing a part of the partition walls while maintaining the line width of the partition walls.

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

  In the information display device configured by removing a part of the partition wall, the partition wall does not exist between all the pixels, but there is a portion where the partition wall does not exist between the pixels. When moving to the counter electrode, there is a case where the display medium diffuses into the adjacent pixel region because there is no partition functioning as a threshold. For this reason, when different colors are displayed in adjacent pixel regions, the display is blurred due to the diffusion of the display medium, resulting in a decrease in display quality. Therefore, when a part of the partition is deleted (thinning the partition), it is necessary to prevent bleeding of the display.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an information display panel and an information display device that improve the aperture ratio while securing display quality by thinning out partition walls in a direction not involved in diffusion of a display medium.

  In order to achieve the above object, the information display panel according to the present invention forms a plurality of cells partitioned by a partition wall between two opposing substrates, at least one of which is transparent, and at least one kind in the cell. An information display panel for enclosing at least one type of display medium composed of particles and displaying information by moving the display medium by an electric field generated in the substrate, in order to define the cell The partition walls parallel to the display surface side electrode among the partition walls provided on the display screen are deleted at predetermined intervals.

As a preferred example of the information display panel of the present invention, the number of removed partition walls corresponding to the predetermined interval is determined according to the area of the pixel accommodated in the cell, and the display medium is a group of particles or powder. It may be fluid.
The information display device of the present invention is configured to mount the information display panel.

  The inventors of the present application observe the above-mentioned “state in which the display is blurred” under a microscope, and the display medium is diffused in a direction parallel to the display surface side electrode, but in a direction perpendicular to the display surface side electrode. Confirmed almost no diffusion. As a result, it was concluded that among the display surface side electrode and the opposing back side electrode arranged in a matrix, the partition perpendicular to the back side electrode, and hence the partition parallel to the display surface side electrode, can be deleted. did. Therefore, in the present invention, a plurality of cells partitioned by partition walls are formed between two opposing substrates, at least one of which is transparent, and at least one or more types composed of at least one type of particles in the cells. Of the partition walls provided for defining the cells when the information display panel is configured to display the information by moving the display medium by the electric field generated in the substrate. By removing the barrier ribs parallel to the side electrodes at predetermined intervals, only the barrier ribs in the direction not involved in the diffusion of the display medium are thinned out at predetermined intervals, so that the aperture ratio can be increased while ensuring display quality. It is possible to provide an information display panel and an information display device that are improved.

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

  First, the configuration of the information display panel of the information display device of the present invention will be described. In the information display device of the present invention, an electric field is applied by some means in the substrate of the information display panel in which the display medium is sealed between the opposing substrates. The display medium charged according to the electric field direction is attracted by an electric field force or a Coulomb force, and the display medium reciprocates by switching the electric field direction, thereby displaying information. Therefore, it is necessary to design the information display panel so that the display medium can move uniformly and maintain stability during repetition or storage. Here, the force applied to the particles or powdered fluid used for the display medium is not only the force attracted by the Coulomb force between the particles or powdered fluid, but also the electric image force with the electrode, intermolecular force, liquid crosslinking force, gravity, etc. Can be considered.

An example of an information display panel applicable to the information display device of the present invention will be described with reference to FIGS.
In the example shown in FIG. 1, at least two or more kinds of display media 3 (here, the white particle group 3 </ b> W and the black particle group 3 </ b> B) composed of at least one kind of particles are connected to the substrates 1 and 2. Depending on the electric field applied from the outside, the substrate is moved perpendicularly to the substrates 1 and 2 and the black particle group 3B is visually recognized by the observer to display black, or the white particle group 3W is visually recognized by the observer. White display. In the example shown in FIG. 1, for example, a partition 4 is provided between the substrates 1 and 2 in a lattice shape to define a display cell.
In the example shown in FIG. 2, at least two or more kinds of display media 3 (here, the white particle group 3 </ b> W and the black particle group 3 </ b> B) composed of at least one kind of particles are provided on the substrate 1. According to the electric field generated by applying a voltage between the electrode 5 and the electrode 6 provided on the substrate 2, the substrate is moved perpendicularly to the substrates 1 and 2, and the black particle group 3B is visually recognized by the observer. Display is performed, or the white particle group 3W is visually recognized by an observer to display white. In the example shown in FIG. 2, partition walls 4 are provided between the substrates 1 and 2, for example, in a lattice shape to define display cells.
In the example shown in FIG. 3, the display medium 3 (here, the white particle group 3 </ b> W) having at least one kind of color composed of at least one kind of particles is connected to the back-side electrode 5 provided on the substrate 1. In accordance with the electric field generated by applying a voltage between the display surface side electrode 6 provided on the substrate 2 and moving it in a direction perpendicular to the substrates 1 and 2, the white particle group 3W is visually recognized by an observer. Or display the color of the electrode 5 or the substrate 1 by making the observer visually recognize the color of the electrode 5 or the substrate 1. In the example shown in FIG. 3, for example, a grid-like partition wall 4 is thinned between the substrates 1 and 2 on the display electrode 6 side to define a display cell.
The above description can be similarly applied to the case where the white particle group 3W is replaced with a white powder fluid and the black particle group 3B is replaced with a black powder fluid.

Hereinafter, the structure of the information display panel, which is a feature of the present invention, will be described with reference to FIGS. 4A, 4B, 5, 6, 6A, 7B, 7A, and 7B. This will be described in detail.
When determining the structure of the information display panel of the present invention, the display surface side electrode 6 and the back side electrode (counter electrode) 5 are arranged in a matrix as shown in FIG. Between the substrates 1 and 2 of the information display panel (hereinafter referred to as 1 × 1 pixel type) before the operation, as shown in FIGS. 6A and 6B, the partition wall 4, the display surface side electrode 6 and the counter electrode 5 are provided. 4 and the structure shown in FIGS. 4A and 4B (hereinafter referred to as a 1 × 2 pixel type). ), The information display panel having the structure shown in FIG. 7A (hereinafter referred to as 1 × 3 pixel type), and the information display panel having the structure shown in FIG. 1 × 4 pixel type) and 2 × 2 pixel type information display panel (not shown) We compared.

  First, when a 2 × 2 pixel type information display panel having a structure in which 2 × 2 pixels are surrounded by a partition wall was prototyped and confirmed, information of 1 × 1 pixel type shown in FIGS. 6A and 6B was obtained. The partition wall can be reduced by about 50% compared to the display panel, and the aperture ratio is improved accordingly. However, as described above, display blur occurs in the direction parallel to the display surface side electrode, and the display quality is improved. Since a decrease was observed, the partition walls in the direction parallel to the display surface side electrode, which is the direction in which the display medium diffuses, were left without being deleted. As a result, a 1 × 2 pixel type information display panel, a 1 × 3 pixel type information display panel, and a 1 × 4 pixel type information display panel remain as candidates.

Next, the 1 × 3 pixel type information display panel shown in FIG. 7A and the 1 × 4 pixel type information display panel shown in FIG. A rear substrate in which a larger number of barrier ribs can be reduced than in the case of using a two-pixel type information display panel and the aperture ratio is further improved, but the barrier ribs are arranged in parallel to the rear electrode. On the side, the display medium moves between adjacent pixel areas along the back side electrode, and the display medium is biased as the display medium is repeatedly moved by moving the display medium. Therefore, the partition walls cannot be easily removed. It turned out that.
It should be noted that the rate at which the partition walls are thinned out, in other words, the number of partition walls to be deleted, is determined according to the area of the pixels accommodated in the cell, but other factors such as display It may be determined in consideration of the gap size between the surface side electrode and the back side electrode and the filling amount of the display medium.

  From the above results, in the present invention, the 1 × 2 pixel type information display panel shown in FIGS. 4A and 4B is employed. The information display panel shown in FIGS. 4A and 4B can be suitably manufactured using the information display panel having the structure shown in FIG. 2, but the information display panel having the structure shown in FIG. Even if it is used, it can be manufactured by providing an electrode outside, and the above-described thinning method can also be applied to the case where an information display panel having the structure shown in FIG. 3 is used. When the 1 × 2 pixel type information display panel shown in FIGS. 4A and 4B is manufactured, this information display panel is the 1 × 1 pixel type shown in FIGS. 6A and 6B. Compared to the information display panel, the partition wall can be reduced by about 25%, and the aperture ratio is improved accordingly. Moreover, the above-described display bleeding in the direction parallel to the display surface side electrode does not occur, which is favorable. Display quality was obtained.

  According to the present invention, every other partition parallel to the display surface side electrode among the partitions provided in a matrix to define the cells enclosing the display medium is deleted. , (B) is adopted, and only the partition walls in the direction not related to the diffusion of the display medium are thinned out every other wall, and approximately 25% of the partition walls are eliminated as a whole, so that the aperture ratio is ensured while ensuring the display quality. It was possible to provide an information display device that can improve the performance.

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

  Regarding the substrate, at least one of the substrates is a transparent substrate capable of confirming the color of the display medium 3 from the outside of the information display panel, and a material having high visible light transmittance and good heat resistance is preferable. The other substrate may be transparent or opaque. Examples of substrate materials include polymer sheets such as polyethylene terephthalate, polyethersulfone, polyethylene, polycarbonate, polyimide, and acrylic, flexible materials such as metal sheets, and flexible materials such as glass and quartz. There are no inorganic sheets. The thickness of the substrate is preferably from 2 to 5000 μm, more preferably from 5 to 2000 μm. If it is too thin, it will be difficult to maintain the strength and the spacing uniformity between the substrates, and if it is thicker than 5000 μm, it will be a thin information display panel. Is inconvenient.

  Electrode forming materials for the electrodes 5 and 6 include metals such as aluminum, silver, nickel, copper, and gold, conductive metal oxides such as ITO, indium oxide, conductive tin oxide, and conductive zinc oxide, polyaniline, and polypyrrole. Examples thereof include conductive polymers such as polythiophene, which are appropriately selected and used. As a method for forming an electrode, a method of forming the above-described materials into a thin film by sputtering, vacuum deposition, CVD (chemical vapor deposition), coating, or the like, or mixing a conductive agent with a solvent or a synthetic resin binder. The method of apply | coating is used. In many cases, the electrode provided on the viewing side substrate needs to be transparent, but in the case of the configuration shown in FIG. 3, it may not be transparent, and the electrode provided on the back side substrate does not need to be transparent. In any case, the above-mentioned material that is conductive and capable of pattern formation 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 are the same as those of the electrode provided on the viewing 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 4 is optimally set according to the type of display medium involved in the display and is not limited in general. However, the width of the partition is 2 to 100 μm, preferably 3 to 50 μm, and the height of the partition is 10 to 10 μm. The thickness is adjusted to 500 μm, preferably 10 to 200 μm. In forming the partition walls, a both-rib method in which ribs are formed on each of the opposing substrates and then bonded, and a one-rib method in which ribs are formed only on one substrate are conceivable. In the present invention, any method is preferably used.

  As shown in FIG. 8, the display cells formed by the partition walls made of these ribs are exemplified by a square shape, a triangular shape, a line shape, a circular shape, and a hexagonal shape when viewed from the substrate plane direction. The shape and the mesh shape are exemplified. It is better to make the portion (the area of the frame portion of the display cell) corresponding to the partition wall cross-sectional portion visible from the display side as small as possible, and the clearness of information display increases. Here, examples of the method for forming the partition include a mold transfer method, a screen printing method, a sand blast method, a photolithography method, and an additive method. Among these, a photolithography method using a resist film and a mold transfer method are preferably used.

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

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

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

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

  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 set to less than 5, preferably less than 3.
Span = (d (0.9) −d (0.1)) / d (0.5)
(However, d (0.5) is a numerical value indicating 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 size 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 is possible.

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

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

  The charge amount of the particles used for the display medium naturally depends on the measurement conditions, but the charge amount of the particles used for the display medium in the information display panel is almost the initial charge amount, the contact with the partition, the contact with the substrate, the elapsed time. It was found that the saturation value of the charging behavior of the particles used in the display medium is a governing factor, depending on the charge decay associated with.

  As a result of intensive studies, the present inventors evaluated the range of the appropriate charging characteristic value of the particles used in the display medium by measuring the charge amount of the particles used in the display medium using the same carrier particles in the blow-off method. I found out that I can do it.

Furthermore, in the present invention, it is important to manage the gas in the void surrounding the display medium between the substrates, 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 gap portion is defined by the electrodes 5 and 6 and the display medium (particle group) from the portion sandwiched between the opposing substrate 1 and substrate 2. Alternatively, the gas portion in contact with a so-called display medium excluding the occupied portion of the powder fluid 3, the occupied portion of the partition wall 4, and the seal portion of the information display panel shall be indicated.
The gas in the gap is not limited as long as it is in the humidity region described above, but dry air, dry nitrogen, dry argon, dry helium, dry carbon dioxide, dry methane, and the like are preferable. This gas needs to be sealed in an information display panel so that the humidity is maintained, for example, filling a display medium, assembling an information display panel, etc. in a predetermined humidity environment, It is important to apply a sealing material and a sealing method that prevent moisture from entering from the outside.

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

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples of the present invention, but the present invention is not limited to the following examples.

<Example 1>
A 1 × 2 pixel type information display panel shown in FIGS. 4A and 4B was produced. Since this information display panel was able to reduce the partition wall by about 25%, the aperture ratio (87.9%) of the 1 × 1 pixel type information display panel shown in FIGS. The aperture ratio was significantly improved to 90.8%. In addition, even when the display medium is moved and display inversion is repeated, the above-described display blur in a direction parallel to the display surface side electrode does not occur, and good display quality is obtained.

<Comparative Example 1>
A 1 × 3 pixel type information display panel shown in FIG. Since this information display panel was able to reduce partition walls in a larger amount (33%) than in Example 1, the aperture ratio was further improved from the aperture ratio (90.8%) in Example 1 above, and 91. It was 8%. However, on the rear substrate side where the partition walls are arranged in parallel to the rear electrode, the display medium moves between adjacent pixel regions along the rear electrode, and the display medium is moved to repeat display inversion. As the display medium is biased, the display quality is deteriorated as compared with the first embodiment.

<Comparative example 2>
A 1 × 4 pixel type information display panel shown in FIG. 7B was produced. Since this information display panel was able to reduce partition walls in a larger amount (37.5%) than in Example 1, the aperture ratio was further improved from the aperture ratio in Example 1 (90.8%). It became 92.3%. However, on the rear substrate side where the partition walls are arranged in parallel to the rear electrode, the display medium moves between adjacent pixel regions along the rear electrode, and the display medium is moved to repeat display inversion. As the display medium is biased, the display quality is deteriorated as compared with the first embodiment.

  An information display panel and an information display device of the present invention include a display unit of a mobile device such as a notebook computer, PDA, mobile phone, and handy terminal, electronic paper such as an electronic book and an electronic newspaper, a signboard, a poster, a bulletin board such as a blackboard, Suitable for display units such as calculators, home appliances, automobile supplies, card display units such as point cards and IC cards, electronic advertisements, electronic POPs, electronic shelf labels, electronic price tags, electronic musical scores, and display units for RF-ID devices Used.

It is a figure which shows an example of the panel for information display used for the information display apparatus of this invention. It is a figure which shows the other example of the information display panel used for the information display apparatus of this invention. It is a figure which shows the further another example of the information display panel used for the information display apparatus of this invention. (A), (b) is a figure for demonstrating the structure of the information display panel of a 1 * 2 pixel type used for the information display apparatus of this invention. It is a figure which shows the display surface side electrode and back surface electrode which are arrange | positioned at matrix form between the two board | substrates which the information display panel of this invention opposes. (A), (b) is a figure for demonstrating the structure of the information display panel of 1x1 pixel type used as the premise of the information display panel of this invention. (A), (b) is a figure for demonstrating the structure of the information display panel of 1x3 pixel type and the information display panel of 1x4 pixel type as a comparative example of the information display apparatus of this invention, respectively. It is. It is a figure which shows an example of the shape of the partition in the information display panel of the information display apparatus of this invention.

Explanation of symbols

1, 2 Substrate 3 Display medium (particle group, powder fluid)
3W White particle group, white powder fluid 3B Black particle group, black powder fluid 4 Bulkhead 5 Electrode (back side electrode; counter electrode)
6 Electrode (Display surface side electrode)

Claims (4)

A plurality of cells partitioned by partition walls are formed between two opposing substrates, at least one of which is transparent, and at least one type of display medium composed of at least one type of particles is enclosed in the cells. An information display panel for displaying information by moving a display medium by an electric field generated in a substrate,
An information display panel characterized in that, among the partition walls provided to define the cells, the partition walls parallel to the display surface side electrode are deleted at predetermined intervals.   The information display panel according to claim 1, wherein the number of deleted partition walls corresponding to the predetermined interval is determined according to an area of a pixel accommodated in the cell.   The information display panel according to claim 1, wherein the display medium is a particle group or a powder fluid.   An information display device comprising the information display panel according to claim 1.

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