JP2006337709A - Panel for information display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a panel for information display, wherein flexibility of a rear substrate with an electrode can be enhanced at low cost, handling of substrates is facilitated and breakage of the panel based on peeling of two substrates is less. <P>SOLUTION: In the panel for information display, wherein a display medium 3 is encapsulated between transparent front and rear substrates 2 and 1 and the display medium is transferred to display information of an image and the like, by applying electric field to the display medium from electrodes, respectively provided on the front and the rear substrates, the rear substrate 1 is constituted of a flexible material and a metal electrode 5 is provided on the rear substrate. The metal electrode 5 is patterned through vapor deposition or sputtering or patterned by etching and the like of a metal film, formed through vapor deposition or sputtering. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention encloses a display medium between a transparent front substrate and a rear substrate, and applies an electric field to the display medium from electrodes provided on each of the front substrate and the rear substrate, thereby moving the display medium to display an image. It is related with the information display panel which displays information, such as these.

  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 one method for solving the various problems described above, a display medium is sealed between a transparent front substrate and a rear substrate, and an electric field is applied to the display medium from electrodes provided on the front substrate and the rear substrate, respectively. Thus, an information display panel that displays information such as an image by moving a 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 front substrate and the rear substrate are bonded to each other in a state where the display medium is filled on the rear substrate or the display medium is filled on the front substrate. Therefore, it is necessary to handle the back substrate itself when filling the display medium with the substrate and bonding the front substrate and the back substrate. At that time, depending on the state of the back substrate, the electrodes provided on the substrate may be peeled off from the substrate, so that it is difficult to handle the back substrate, or various functions that work on the information display panel obtained by bonding the two substrates together. There was a problem that the two substrates were peeled off due to stress and the panel was easily damaged. In particular, in the case of an information display panel that may bend the display surface, such as electronic paper, the above problem is significant.

  In general, conventional information display panels use a glass substrate as a substrate material and ITO (Indium Tin Oxide) as an electrode material. However, both the glass material and the ITO material have low flexibility, and the above problems are avoided. In addition to being unable to solve the problem, there is a problem that the price is high and the cost of the information display panel becomes high.

  The object of the present invention is to solve the above-mentioned problems, increase the flexibility of the back substrate with electrodes at low cost, facilitate the handling of the substrate, and information with little damage to the panel based on the separation of the two substrates. It is intended to provide a display panel.

  The information display panel of the present invention encloses a display medium between a transparent front substrate and a rear substrate, and applies an electric field to the display medium from electrodes provided on each of the front substrate and the rear substrate. In the information display panel that displays information such as images by moving the back plate, the back substrate is made of a flexible material, and a metal electrode patterned by vapor deposition or sputtering is formed on the back substrate, or on the back substrate. A metal electrode formed by patterning a metal film formed by vapor deposition or sputtering is provided.

  In addition, as a suitable example of the information display panel of this invention, the thickness of a metal electrode is 0.01-1 micrometer, the material of a metal electrode is aluminum, and the flexible material which comprises a back substrate is resin. And the resin is PET (Polyethylene Terephthalate) or PEN (Polyethylene Naphthalate).

  According to the present invention, the rear substrate is made of a flexible material and is formed by patterning a metal electrode formed by vapor deposition or sputtering on the rear substrate or a metal film formed by vapor deposition or sputtering on the rear substrate. By providing such a metal electrode, flexibility can be imparted to the back substrate, the substrate can be easily handled, and an information display panel can be obtained in which the panel is less damaged due to the separation of the two substrates. In addition, metal, particularly aluminum, is an electrode material that is very inexpensive and can be formed by vapor deposition or sputtering, and patterning processing such as etching is easy. Further, by combining with a back substrate made of a resin material, particularly a back substrate made of PET or PEN, A very inexpensive back substrate having flexibility can be obtained, and the cost of the information display panel can be reduced.

  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 an information display panel manufactured according to the manufacturing method of the present invention will be described with reference to FIGS. 1 (a) and (b) to FIGS. 2 (a) and 2 (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. 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. 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, one type of display medium 3 (here, a white display medium consisting of a group of particles) having optical reflectivity and chargeability composed of at least one type 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. 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.)

  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.

  The present invention is characterized in that, in the information display panel using the display medium having the above-described configuration, the back substrate (corresponding to the substrate 1, hereinafter referred to as “1” in some cases) is made of a flexible material, and the back substrate A metal electrode formed by patterning by vapor deposition or sputtering or a metal electrode formed by patterning such as etching on a metal film formed by vapor deposition or sputtering on the back substrate (electrode 5 in FIG. 1, electrode 5 in FIG. 2, and electrode) 6, hereinafter referred to as “5” in some cases). In order to directly pattern the electrode shape (line shape), it is conceivable to use a mask during sputtering.

  More specifically, the metal electrode 5 preferably has a thickness of 0.01 to 1 μm. Here, it is preferable that the thickness of the metal electrode 5 is 0.01 to 1 μm. If the thickness is less than 0.01 μm, it is difficult to make the in-plane electrode thickness uniform, and the in-plane resistance value. Becomes non-uniform, causing disconnection of electrodes and non-uniform display. On the other hand, when the thickness of the metal electrode 5 exceeds 1 μm, the particles for the display medium are sandwiched between the electrodes of the patterned electrode substrate and cannot fly, which causes the display state to deteriorate. Further, the metal electrode material is aluminum, the flexible material constituting the back substrate is a resin, and the resin is PET (Polyethylene Terephthalate) or PEN (Polyethylene Naphthalate). It is more effective to achieve the back substrate 1 provided with the flexible electrode 5 and is a preferable embodiment.

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

  As for the substrate, the front substrate is a transparent substrate 2 (hereinafter, the front substrate is sometimes referred to as symbol 2) that can confirm the color of the display medium from the outside of the information display panel, and has high visible light transmittance and heat resistance. A good material is suitable. The back substrate 1 may be transparent or opaque. Examples of the front substrate material include flexible materials such as polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyethylene, polycarbonate, polyimide, acrylic and other polymer sheets, and flexible materials such as glass and quartz. An inorganic transparent sheet having no surface. When the back substrate material is exemplified, a flexible polymer sheet such as polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyethylene, polycarbonate, polyimide, acrylic, or a metal sheet is preferable. 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.

Examples of the electrode material provided on the back substrate of the information display panel include metals such as aluminum, silver, nickel, copper, and gold, which are appropriately selected and used. In the present invention, it is preferable to use aluminum. The electrode can be formed by patterning the above exemplified materials by sputtering, vacuum deposition, CVD (chemical vapor deposition) or the like, or by sputtering, vacuum deposition, CVD (chemical vapor deposition), etc. A method of forming by performing a patterning process such as etching after the formation is used.
Electrode materials provided on the transparent front substrate on the display surface side include conductive metal oxides such as ITO (indium tin oxide), indium oxide, conductive tin oxide, and conductive zinc oxide, and conductive materials such as polyaniline, polypyrrole, and polythiophene. Are exemplified and used as appropriate. In this case, the electrode may be formed by sputtering, vacuum deposition, CVD (chemical vapor deposition), coating or the like to form a thin film, or using a conductive agent as a solvent or a synthetic resin binder. It is formed by adding a patterning process to a method of applying by mixing. In any case, the above-mentioned material that can be patterned and is electrically conductive can be suitably used. The thickness of the electrode provided on the front substrate 2 may be 3 to 1000 nm, preferably 5 to 400 nm, as long as the conductivity is ensured and the light transmittance is not hindered. The thickness of the electrode provided on the back substrate 1 may be 0.01 to 1 μm, as long as the conductivity is ensured and the adhesion to the substrate and the flexibility are not hindered. In this case, the external voltage input may be superimposed with direct current or alternating current.

  The height and width of the partition walls 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 wall width is 2 to 100 μm, preferably 3 to 50 μm, and the partition wall height 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, 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.

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 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 the display medium can be moved uniformly.

  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, 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 void 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, 2A, and 2B, 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.

(Relationship between back substrate and electrode)
Example 1 in which an electrode was formed by vapor-depositing aluminum (Al) on a back substrate made of PET, Example 2 in which an electrode was formed by sputtering aluminum (Al) on a back substrate made of PEN, and a back substrate made of PET Comparative Example 1 in which ITO was patterned by photolithography was prepared. In any example, the thickness of the back substrate was 100 μm, and the thickness of the electrode was 0.06 μm. Actually, as shown in FIG. 4, electrodes are formed on the back substrate cut to 1 cm × 10 cm so as to have a predetermined pattern, and a 90-degree bending test is performed with a radius of curvature of 5 mm using the apparatus of FIG. The electrode resistance value after bending 10 times and after bending 100 times was measured. The electrode resistance value was measured by applying a DC voltage of 1 V between terminals A and B provided at both ends of the back substrate electrode. The change in the electrode resistance value when the initial electrode resistance value is 1 is shown in Table 1 below.

  From the results of Table 1, in Examples 1 and 2, the electrode resistance value did not change even after the 90-degree bending test, whereas in Comparative Example 1, the electrode was gradually cut after the 90-degree bending test and the resistance value increased. Thus, it can be seen that Examples 1 and 2 have the flexibility required by the present invention.

(About electrode thickness)
A glass transparent substrate with line-like ITO electrodes (7 cm × 7 cm □) was prepared as a front substrate, ribs with a height of 50 μm were made, and square-shaped and grid-like partition walls were formed. The partition walls were formed on the front substrate as follows. A dry film resist NIT250 manufactured by Nichigo Morton, which is a photosensitive film, was laminated on a glass with line-shaped ITO electrodes, 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. On the back substrate, aluminum (Al) is vapor-deposited on a PET substrate (7 cm × 7 cm □), and line electrodes having thicknesses of 0.005 μm, 0.01 μm, 0.1 μm, 1.0 μm, and 1.5 μm are formed on ITO. Each prepared by patterning by the same photolithography method as glass was prepared.

  Next, after filling the cells divided by the partition walls on the front substrate with display media having different charging characteristics of two colors, black and white, the rear substrate side is handled and the two substrates are bonded to form an information display panel. Each of the produced information display panels was connected to a driving device, the display medium was driven to display information, and the display quality was evaluated by observing the display state. The results are shown in Table 2 below.

  From the results of Table 2, in Examples 11 to 13, the electrode thickness was set to 0.01 to 1.0 μm, so that a good display quality was obtained as an information display panel, whereas in Example 14, The display medium is presumed to be sandwiched between the electrodes, and there are some cells that do not drive and the display quality is low. In Example 15, the display medium is driven at the portion corresponding to the disconnection generating electrode. The display quality was lower than that of Example 14. From this result, it is understood that the electrode thickness is preferably 0.01 to 1.0 μm.

  The information display panel of the present invention is a display unit of a mobile device such as a notebook computer, PDA, mobile phone, or handy terminal, electronic paper such as an electronic book or electronic newspaper, a bulletin board such as a signboard, a poster, or a blackboard, a calculator, or a home appliance. 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 in the information display panel of this invention, respectively. (A), (b) is a figure which shows the structure of the other example in the information display panel of this invention, respectively. It is a figure which shows an example of the shape of the partition in the information display panel of this invention. It is a figure which shows the shape of the sample used in the Example of this invention. It is a figure for demonstrating an example of the bending test used in the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Back substrate 2 Front substrate 3 Display medium 3W White display medium 3Wa White display medium particle 3B Black display medium 3Ba Black display medium particle 4 Bulkhead 5, 6 Electrode

Claims (5)

  A display medium is sealed between a transparent front substrate and a rear substrate, and an electric field is applied to the display medium from electrodes provided on the front substrate and the rear substrate, thereby moving the display medium to display information such as an image. In the information display panel to be displayed, the rear substrate is made of a flexible material, and a metal electrode patterned by vapor deposition or sputtering is formed on the rear substrate, or a metal film formed by vapor deposition or sputtering on the rear substrate. An information display panel provided with a metal electrode formed by patterning.   The information display panel according to claim 1, wherein the metal electrode has a thickness of 0.01 to 1 μm.   The information display panel according to claim 1, wherein a material of the metal electrode is aluminum.   The information display panel according to any one of claims 1 to 3, wherein the flexible material constituting the back substrate is a resin.   5. The information display panel according to claim 4, wherein the resin is PET (Polyethylene Terephthalate) or PEN (Polyethylene Naphthalate).

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