JP4565864B2 - Manufacturing method of image display panel - Google Patents

Description

  The present invention relates to a first substrate having at least one transparent substrate, the first substrate having an electrode portion formed on the surface, and the second substrate having an electrode portion formed on the surface and a partition defining a display cell. Are stacked so that the electrode portions face each other, and a particle group or a powder fluid is sealed between them.

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

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

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

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

As a method for solving the various problems described above, a cell isolated from each other by a partition is formed between a front substrate and a rear substrate, and a particle group or a powder fluid is enclosed in the cell. 2. Description of the Related Art An image display device including an image display panel that displays an image by applying an electric field to a fluid and moving particles or powdered fluid by Coulomb force or the like 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 image display device described above, at least one of the substrates is usually a transparent opposing substrate, and a first substrate having an electrode portion formed on the surface and an electrode portion formed on the surface and a partition defining a display cell are formed. An image display panel having a structure in which the second substrate is overlapped so that the electrode portions face each other and a particle group or powder fluid is sealed therebetween is used. In this image display panel, a process of filling a particle group or a powder fluid into a display cell defined by partition walls is important. Conventionally, a device similar to a dry LCD spraying device has been used in the particle group or powder fluid filling process.

  In the image display panel and the liquid crystal panel using the particle group or powdered fluid that is the subject of the present invention, since the filling amount and charging characteristics of the particle group and the like are large, if the same device as the LCD spraying device is used as it is, There have been problems that the filling speed is slow and that the amount of packed particles is not uniform. As described above, when the filling amount is not uniform in each display cell of the panel, there is a problem that unevenness occurs in the display of the image display panel.

  An object of the present invention is to solve the above-mentioned problems, and to provide a method for manufacturing an image display panel having a high filling speed and a uniform filling amount of particle groups and the like, and as a result, no image display unevenness. It is.

In the method for manufacturing an image display panel according to the present invention, at least one is a transparent opposing substrate, and a first substrate having an electrode portion formed on the surface and an electrode portion formed on the surface and a display cell are defined. In the method for manufacturing an image display panel having a structure in which a second substrate on which a partition wall is formed is overlapped so that the electrode portions face each other, and a charged particle group or charged powder fluid is sealed therebetween. per the electrode portion of the substrate while equipotential, to fill by spraying in the display cell particles or liquid powders, the necessary amount of the particles or the liquid powders in a second display cells on a substrate In addition, a conductive mask is provided in a part where particles or powder fluid is not required to be filled, and the potential difference between the conductive mask and the electrode portion on the second substrate is set to 100 V or less. .
The image display panel manufacturing method of the present invention includes a first substrate having at least one transparent substrate, the electrode portion being formed on the surface, the electrode portion being formed on the surface, and the display cell being defined. In the method of manufacturing an image display panel having a structure in which a second substrate on which a partition wall is formed is overlapped so that the electrode portions face each other and a charged particle group or charged powder fluid is sealed therebetween, Filling the display cell on the second substrate with the required amount of particle group or powder fluid by spraying the particle group or powder fluid into the display cell with the electrode part of the second substrate being equipotential In doing so, a conductive mask is provided in a part where particles or powder fluid is not required to be filled, and the conductive mask and the electrode portion on the second substrate are equipotential.

Further, as a preferable embodiment of the production method of the image display panel of the present invention, the shape of the mask is larger than the shape of the substrate, first the surface facing the second substrate conductive mask conductive 1 Are provided on the surface of the conductive mask facing the stage on which the second substrate is placed, and the first protrusion is provided on the electrode portion on the second substrate. In the state where the two protrusions are electrically connected to the stage, respectively, the particle group or powder fluid is filled, the conductive mask is connected to the ground, and the electrode part on the second substrate is connected to the ground. Have connected.

  According to the present invention, in a state where the electrode portion of the second substrate is at an equipotential, the necessary amount of the particle group or the powder fluid is distributed on the second substrate by dispersing the particle group or the powder fluid in the display cell. By filling the display cells, it is possible to uniformly fill the display cells between the substrates with particles or powder fluid. Even if the filling speed is increased, uniform filling is possible. As a result, image display unevenness can be eliminated in the image display panel.

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

  Next, an image display operation in the basic configuration of the above-described image display panel will be described. The image display panel used in the present invention is, for example, by moving particles 3 of two different colors (see FIG. 1; here, white particles 3W and black particles 3B) are moved in a direction perpendicular to the substrates 1 and 2. The present invention can be applied to both a panel used for a display method and a panel using a display method by moving particles 3W of one kind of color (see FIG. 2) in a direction parallel to the substrates 1 and 2. An example of a panel structure for display is shown in FIG. In FIGS. 1 to 3, 4 is a partition provided as necessary to form a cell, and 5 and 6 are electrodes provided for applying an electric field to the particles 3. The above description can be similarly applied to the case where the white particles 3W are replaced with the white powder fluid and the black particles 3B are replaced with the black powder fluid.

Hereinafter, a method for producing an image display panel, which is a feature of the present invention, will be described in detail.
4 to 7 are diagrams for explaining each step in the method of manufacturing an image display panel according to the present invention. First, as shown in FIG. 4, a substrate 1 as a second substrate is prepared. On the surface of the substrate 1, striped electrodes 5 made of ITO electrodes are provided by patterning. In this example, an example in which twelve substrates 1 are taken from one mother glass substrate 11 is shown. The striped electrodes 5 on each substrate 1 on the mother glass substrate 11 are connected to each other by ITO electrodes 12 at one end, and the striped electrodes 5 connected to each substrate 1 are also ITO electrodes 12. Are connected to each other.

Next, for each substrate 1, grid-like, mesh-like, or honeycomb-like partition walls 4 (not shown here) that define display cells are formed on the electrodes 5 of the substrate 1.
Since each stripe-shaped electrode 5 corresponds to the size of the display cell that is the minimum unit of image display, the stripe-shaped electrode 5 actually corresponds to the size and resolution of the image display panel. However, only 12 are shown here for convenience of explanation.

  Next, as shown in FIG. 5, a conductive mask 13 is provided in a portion other than the portion used as the substrate 1 in the mother glass substrate 11 in a portion where the particle group or the powder fluid is not required to be filled. When the mask 13 is provided, a dummy spacer 14 is disposed between the mask 13 and the ITO electrode 12 portion of the mother glass substrate 11 as shown in FIG. The dummy spacer 14 is formed on the substrate 1 when the partition 4 is formed. The shape of the mask 13 is not particularly limited, but if the shape of the mask 13 is larger than the shape of the mother glass substrate 11, it is possible to prevent the particles or powder fluid 3 from wrapping around from the side surface. It is preferable because the powder fluid 3 does not adhere.

  Next, as shown in FIG. 6, the mother glass substrate 11 is set together with the mask 13 on the stage 16 in the spraying device 15. In this state, by spraying the particle group or powdered fluid 3 from the nozzle 17 into the spraying device 15, a predetermined amount of the particle group or powdered fluid 3 is filled in the display cells defined by the partition walls 4 on each substrate 1. can do.

  Next, the mask 13 is removed, and unnecessary particle groups or powder fluid 3 on the partition walls 4 are removed. Thereafter, a transparent substrate (not shown here) corresponding to the substrate 1 and the substrate 1 is overlapped and adhered to the substrate 1 filled with the particle group or powder fluid 3 in the display cell, and the particle group or The powder fluid 3 is sealed in the display cell. Finally, by cutting out 12 panels from the mother glass substrate 11, the image display panel of the present invention can be manufactured.

  At the time of this cutting out, the striped electrode 5 connected at one end becomes a single striped electrode 5 by cutting off the connecting portion. Moreover, in the example shown in FIG. 6, the magnitude | size of the particle group or the powder fluid 3 is drawn larger than actual for convenience of explanation. Further, on the surface of the front substrate 2 facing the back substrate 1, stripe electrodes 6 are provided in a direction perpendicular to the stripe direction of the substrate 1.

  The greatest feature of the method for manufacturing an image display panel according to the present invention is that all the striped electrodes 5 on the substrate 1 are made equipotential in the filling step shown in FIG. That is, in the example shown in FIG. 6, the ITO electrode 12 on the mother glass substrate 11 is connected to the ground and grounded, so that all the electrodes 5 are set to the ground potential. In the example shown in FIG. 6, the mask 13 is also connected to the ground so as to have a ground potential equal to that of the ITO electrode 12. The stage 16 is normally at a ground potential.

  Although the mask 13 is used in the above-described example, the example using the mask 13 is a preferred example, and the mask 13 is not an essential configuration in the present invention. Further, as long as the electrode 5 is equipotential, the electrode 5 and the mask 13 do not need to be at the same potential. However, it is preferable that the potential difference between the electrode 3 and the mask 13 is 100 V or less in order to achieve uniform filling of the particle group or the powder fluid 3.

  According to the method for manufacturing an image display panel of the present invention having the above-described configuration, when a device similar to the conventional LCD spacer dispersing device is used, that is, when the state of the electrode 5 on the substrate 1 is not considered at all. , The particle group or the powder fluid 3 can be uniformly filled in the display cell. In particular, as in the example described above, when a plurality of substrates 1 are manufactured simultaneously from the mother glass substrate 11, 12 ITO electrodes 12 are patterned by patterning while the ITO electrodes 12 are connected to the mother glass substrate 11. Therefore, the present invention in which all of the electrodes 5 can be electrically connected and all of the electrodes 5 need to be equipotential can be implemented more suitably.

  In the method for manufacturing an image display panel according to the present invention, as shown in FIG. 7, the conductive first protrusion 21 is formed on the surface of the conductive mask 13 facing the mother glass substrate 11, and the conductive mask 13. Conductive second protrusions 22 are respectively provided on the surface facing the stage 16 on which the mother glass substrate 11 is placed, and the first protrusions 21 are formed on the ITO electrodes 12 on the mother glass substrate 11 and the second protrusions 22. Can be filled with a particle group or a powder fluid in a state in which the stage 16 is electrically connected to each other. With this configuration, the mask 13, the ITO electrode 12, and the stage 16 can all be made equipotential easily.

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

  As for the substrate, at least one substrate is the transparent front substrate 2 from which the color of particles or powder fluid can be confirmed from the outside of the apparatus, and a material having high visible light transmittance and good heat resistance is suitable. The back substrate 1 may be transparent or opaque. Examples of substrate materials include polymer sheets such as polyethylene terephthalate, polyethersulfone, polyethylene, polycarbonate, polyimide, and acrylic, flexible materials such as metal sheets, and flexible materials such as glass and quartz. There are no inorganic sheets. The thickness of the substrate is preferably 2 to 5000 μm, and more preferably 5 to 2000 μm. If it is too thin, it will be difficult to maintain the strength and the uniform spacing between the substrates, and if it is thicker than 5000 μm, it is inconvenient for a thin display panel. There is.

  As for the electrode, the front electrode provided on the front substrate side that needs to be transparent on the viewing side is formed of a conductive material that is transparent and can be patterned. For example, indium oxide, aluminum, gold, silver, copper Metals such as polyaniline, conductive polymers such as polypyrrole, polythiophene, and the like, and examples of the forming method such as vacuum deposition and coating. 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 back electrode provided on the back substrate side are the same as those of the above-described front electrode, 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 wall 4 is optimally set according to the type of particle group or powder fluid involved in the display, and is not limited in general. However, the partition wall width is 2 to 100 μm, preferably 3 to 50 μm. Is adjusted to 10 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 corresponding to the cross section of the partition wall visible from the display side (the area of the frame portion of the display cell) as small as possible, and the sharpness of the image display increases. Here, examples of the method for forming the partition include a screen printing method, a sand blasting method, a photolithography method, and an additive method. Of these, the photolithography method using a resist film is preferably used.

  Next, the particles used in the image display panel that is the subject of the present invention will be described. The particles can contain a charge control agent, a colorant, an inorganic additive, and the like, if necessary, in the resin as the main component, as in the conventional case. Examples of resins, charge control agents, colorants, and other additives will be given below.

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

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

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

Examples of the black colorant include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon and the like.
Examples of blue colorants include C.I. I. Pigment brie 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.

  The particles used in the present invention preferably have an average particle diameter d (0.5) in the range of 0.1 to 50 μm and are uniform and uniform. If the average particle diameter d (0.5) is larger than this range, the display is not clear, and if it is smaller than this range, the cohesive force between the particles becomes too large, which hinders the movement of the particles.

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

  Furthermore, regarding the correlation between the particles, the ratio of d (0.5) of the particles having the minimum diameter to d (0.5) of the particles having the maximum diameter among the used particles is set to 50 or less, preferably 10 or less. It is essential. 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 naturally depends on the measurement conditions, but the charge amount of the particles in the image display panel almost depends on the initial charge amount, the contact with the partition wall, the contact with the substrate, the charge decay with the elapsed time, In particular, it was found that the saturation value of the charging behavior of the two types of particles is the dominant factor.

  As a result of intensive studies, the present inventors have found that by using the same carrier particles in the blow-off method and measuring the charge amount of each particle, it is possible to evaluate the range of appropriate charging characteristic values of the two types of particles. It was.

  Although the measurement method will be described in detail later, the charge amount per unit weight of the particles can be measured by sufficiently bringing the particles and carrier particles into contact with each other by the blow-off method and measuring the saturated charge amount. Then, by separately obtaining the average particle diameter and specific gravity of the particles, the total number of particles and the charge amount per particle can be calculated.

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

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

The image display panel which is an object 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 in a gas between opposite 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, the pulverized fluid used in the present invention is a substance in the intermediate state of both fluid and particle characteristics that exhibits fluidity by itself without borrowing the force of gas or liquid. This powder fluid can be in an aerosol state in particular, and in the image display device of the present invention, a solid substance is used in a state of relatively stably floating as a dispersoid in the gas.

The range of the aerosol state is preferably such that the apparent volume of the pulverized fluid when it is floated is twice or more that when it is not suspended, more preferably 2.5 times or more, and particularly preferably 3 times or more. Although an upper limit is not specifically limited, It is preferable that it is 12 times or less.
If the apparent volume of the pulverized fluid is less than twice that of the unfloating state, it is difficult to control the display, and if it is more than 12 times, the powder fluid will be overloaded when sealed in the device. Inconvenience in handling occurs. The apparent volume at the maximum floating time is measured as follows. That is, the powdered fluid is put into a closed container that allows the powdered fluid to permeate, and the container itself is vibrated or dropped to create a maximum floating state, and the apparent volume at that time is measured from the outside of the container. Specifically, in a container with a lid (trade name: iBoy: manufactured by ASONE Co., Ltd.) having a diameter (inner diameter) of 6 cm and a height of 10 cm, the powder fluid corresponding to 1/5 of the volume of the fluid when not floating. And set the container on a shaker, and shake at a distance of 6 cm at 3 reciprocations / sec for 3 hours. The apparent volume immediately after stopping shaking is the apparent volume at the maximum floating time.

Moreover, in this invention, what the time change of the apparent volume of a powder fluid satisfy | fills following Formula is preferable.
V ₁₀ / V ₅ > 0.8
Here, V ₅ represents an apparent volume (cm ³ ) 5 minutes after the maximum floating time, and V ₁₀ represents an apparent volume (cm ³ ) 10 minutes after the maximum floating time. In the image display device of the present invention, the apparent volumetric change V ₁₀ / V ₅ of the powder fluid is preferably larger than 0.85, and more preferably larger than 0.9. When V ₁₀ / V ₅ is 0.8 or less, it becomes the same as when ordinary so-called particles are used, and it becomes impossible to ensure the effect of high-speed response and durability as in the present invention.

  Moreover, the average particle diameter (d (0.5)) of the particulate material constituting the powder fluid is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and particularly preferably 0.9 to 8 μm. . If it is smaller than 0.1 μm, it is difficult to control the display, and if it is larger than 20 μm, the display is not clear. The average particle diameter (d (0.5)) of the particulate material constituting the powder fluid is the same as d (0.5) in the next particle diameter distribution Span.

The particle substance constituting the powder fluid preferably has a particle size distribution Span represented by the following formula of less than 5, more preferably less than 3.
Particle size distribution Span = (d (0.9) -d (0.1)) / d (0.5)
Here, d (0.5) is a numerical value expressed in μm of the particle diameter that 50% of the particulate material constituting the powder fluid is larger than this and 50% is smaller than this, and d (0.1) is less than this. A numerical value in which the ratio of the particle substance constituting the powder fluid is 10%, expressed in μm, and d (0.9) is the particle diameter in which the particulate substance constituting the powder fluid is 90% μm It is a numerical value expressed by By setting the particle size distribution Span of the particulate material constituting the powder fluid to 5 or less, the sizes are uniform and uniform powder fluid movement becomes possible.

  The above particle size distribution and particle size can be obtained from a laser diffraction / scattering method or the like. When laser light is irradiated to the powder fluid to be measured, a light intensity distribution pattern of diffracted / scattered light is generated spatially, and this light intensity pattern has a corresponding relationship with the particle diameter, so the particle diameter and particle diameter distribution are measured. it can. This particle size and particle size distribution are obtained from a volume-based distribution. Specifically, using a Mastersizer2000 (Malvern Instruments Ltd.) measuring machine, the powdered fluid was introduced into a nitrogen stream, and the attached analysis software (software based on volume reference distribution using Mie theory) Measurements can be made.

  Preparation of powder fluid can be done by kneading and pulverizing the necessary resin, charge control agent, colorant, and other additives, or by polymerization from monomers, and adding existing particles to resin, charge control agent, colorant, and other It may be coated with an agent. Hereinafter, the resin, charge control agent, colorant, and other additives constituting the powder fluid will be exemplified.

  Examples of the resin include urethane resin, acrylic resin, polyester resin, urethane-modified acrylic resin, silicone resin, nylon resin, epoxy resin, styrene resin, butyral resin, vinylidene chloride resin, melamine resin, phenol resin, fluorine resin, etc. Two or more types can also be mixed. In particular, acrylic urethane resin, acrylic urethane silicone resin, acrylic urethane fluororesin, urethane resin, and fluororesin are preferable from the viewpoint of controlling the adhesive force with the substrate.

  Examples of charge control agents include quaternary ammonium salt compounds, nigrosine dyes, triphenylmethane compounds, imidazole derivatives and the like in the case of imparting positive charges, and metal-containing azo compounds in the case of imparting negative charges. Examples thereof include dyes, salicylic acid metal complexes, and nitroimidazole derivatives.

  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 brie 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.

Furthermore, in the present invention, it is important to manage the gas in the voids surrounding the particle group or the powder fluid between the substrates, which contributes to the improvement of 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.
1 to 3, the space between the opposing substrate 1 and substrate 2 in FIGS. 1 to 3, the occupied portion of the electrodes 5, 6, the particle group (or powder fluid) 3, the occupied portion of the partition 4, and the device A gas portion that is in contact with a so-called particle group (or powder fluid) excluding the seal portion is meant.
The gas in the gap is not limited as long as it is in the humidity region described above, but dry air, dry nitrogen, dry argon, dry helium, dry carbon dioxide, dry methane, and the like are preferable. This gas needs to be sealed in the apparatus so that the humidity is maintained. For example, filling of particles or powder fluid, assembly of the substrate, etc. are performed in a predetermined humidity environment, It is important to apply a sealing material and a sealing method to prevent moisture intrusion.

The distance between the substrate in the image display panel of the present invention is not limited as long as the particle group or powder fluid can move and maintain the contrast, but is usually adjusted to 10 to 500 μm, preferably 10 to 200 μm.
The volume occupancy of the particle group or powder fluid in the space between the opposing substrates is preferably 5 to 70%, more preferably 5 to 60%. If it exceeds 70%, the movement of particles or powder fluid is hindered, and if it is less than 5%, the contrast tends to be unclear.

Hereinafter, an actual example will be described.
An example in which no voltage is applied to the ITO electrode 12 on the mother glass substrate 11 and the mother glass substrate 11 is not equipotential in accordance with the method of filling the particle group or powder fluid shown in FIG. 6 (using the mask 13 in FIG. 6) No), an example in which the ITO electrode 12 on the mother glass substrate 11 is equipotential (without using the mask 13 in FIG. 6), and further, an ITO electrode on the mother glass substrate 11 using the conductive mask 13 In the case where the potential of the ITO electrode 12 on the mother glass substrate 11 and the potential of the conductive mask 13 are variously changed as shown in Table 1 below, The uniformity of filling of the powder composed of the particle group or the powder fluid 3 at the time of filling was examined by visual inspection, and the problem and the trouble in the subsequent process were examined.

<Regarding particle groups>
In the experiment, a group of white particles of −30 μC / m ^{2 in} the charge amount indicated by the surface charge density obtained by the blow-off method before spraying was used. The results are shown in Table 1 below. In Table 1, as for the uniformity of the particle group packing, ◎ indicates a very good state, ○ indicates a good state, △ indicates a normal state, and × Indicates that the uniformity is poor. Furthermore, the defect of a post process WHEREIN: In all processes including the manufacturing process of the particle group after a filling process, etc., the thing without a defect was set to (circle), and the thing with a defect was set to x.

  From the results in Table 1, the test No. 1 and test no. By comparing 2 to 15, it can be seen that the uniformity of the particle group filling is improved by making the electrode portion of the substrate equipotential in the filling step. In addition, Test No. 2-5 and Test No. By comparing 6 to 12, it can be seen that even when the electrode portion of the substrate is equipotential, the use of a mask further improves the uniformity of the particle group filling. Furthermore, test no. By comparing 6 to 12, it can be seen that the uniformity in filling the particle group is further improved by setting the potential difference between the electrode portion of the substrate and the mask to 100 V or less. Furthermore, test no. 6 and 13 to 15, the best uniformity is obtained by setting the potential difference between the electrode portion of the substrate and the mask to 0 V, and connecting the electrode portion of the substrate and the mask to the ground. I understand that. Further, it was found that the same potential between the electrode portion and the mask potential had good uniformity, and when the potential difference between them was large, the amount of the particle group at the edge portion became non-uniform. Furthermore, it can be seen that when a mask is used, a problem occurs in a later process.

<About powder fluid>
In the experiment, a white powder fluid of −20 μC / m ^{2 in} the charge amount indicated by the surface charge density obtained by the blow-off method before spraying was used. The results are shown in Table 2 below. In Table 2, the uniformity of powder fluid filling is as follows: ◎ indicates very good uniformity, ◯ indicates good uniformity, △ indicates normal uniformity, × Indicates that the uniformity is poor. Furthermore, the defect of a post process WHEREIN: In all the processes including the manufacturing process of the powder fluid after a filling process, etc., what did not have a defect was set to (circle), and the thing with a defect was set to x.

  From the results in Table 2, the test No. 21 and test no. By comparing 22 to 35, it can be seen that the uniformity of the powder fluid filling is improved by making the electrode portion of the substrate equipotential in the filling step. In addition, Test No. 22-25 and test no. 26 to 32, it can be seen that even when the electrode portion of the substrate is equipotential, the use of a mask further improves the uniformity when filling the powder fluid. Furthermore, test no. By comparing 26 to 32, it can be seen that the uniformity in filling the powdered fluid is further improved by setting the potential difference between the electrode portion of the substrate and the mask to 100 V or less. Furthermore, test no. 26, 33 to 35, the best uniformity is obtained by setting the potential difference between the electrode portion of the substrate and the mask to 0 V and connecting the electrode portion of the substrate and the mask to the ground. I understand that. In addition, it was found that the electrode potential and the mask potential were the same, and the uniformity was good, and when the potential difference between the two became large, the amount of powder fluid at the edge portion became non-uniform. Furthermore, it can be seen that when a mask is used, a problem occurs in a later process.

  The image display panel manufactured according to the manufacturing method of the present invention has no image unevenness, display unit of mobile devices such as notebook computers, PDAs, mobile phones, handy terminals, electronic paper such as electronic books and electronic newspapers, signs, posters, Suitable for bulletin boards such as blackboards, display units for calculators, home appliances, automotive products, card display units such as point cards and IC cards, electronic advertisements, electronic POPs, electronic price tags, electronic musical scores, and display units for RF-ID devices Used for.

It is a figure which shows an example of the drive method in the image display panel used as the object of the manufacturing method of this invention. It is a figure which shows the other example of the drive method in the image display panel used as the object of the manufacturing method of this invention. It is a figure which shows an example of the structure of the image display panel used as the object of the manufacturing method of this invention. It is a figure for demonstrating the preparatory process of the board | substrate and electrode in the manufacturing method of the image display panel of this invention. It is a figure for demonstrating the preparatory process of the mask in the manufacturing method of the image display panel of this invention. It is a figure for demonstrating the filling process of the particle group or powder fluid in the manufacturing method of the image display panel of this invention. It is a figure for demonstrating the other process in the manufacturing method of the image display panel of this invention. It is a figure which shows an example of the shape of the partition in the image display panel used as the object of the manufacturing method of this invention.

Explanation of symbols

1 Rear substrate 2 Front substrate 3 Particles (powder fluid)
3W white particles (white powder fluid)
3B Black particles (black powder fluid)
4 Partition 5 Back electrode 6 Front electrode 11 Mother glass substrate 12 ITO electrode 13 Mask 14 Dummy spacer 15 Dispersing device 16 Stage 17 Nozzle 21 First protrusion 22 Second protrusion

Claims (6)

At least one of the transparent substrates is a transparent substrate, and a first substrate having an electrode portion formed on the surface and a second substrate having an electrode portion formed on the surface and a partition defining a display cell are mutually connected. the electrode portions superposed so as to face, in the manufacturing method of the image display panel of the charged particles or charged liquid powders a sealing structure between them, while the electrode portion of the second substrate to the equipotential In order to fill the display cell on the second substrate with a necessary amount of the particle group or the powder fluid by dispersing the particle group or the powder fluid in the display cell, it is electrically conductive to the unnecessary part of the particle group or the powder fluid. And a potential difference between the conductive mask and the electrode portion on the second substrate is set to 100 V or less . At least one of the transparent substrates is a transparent substrate, and a first substrate having an electrode portion formed on the surface and a second substrate having an electrode portion formed on the surface and a partition defining a display cell are mutually connected. In the method of manufacturing an image display panel having a structure in which charged electrode groups or charged powder fluids are sealed between the electrodes so that the electrode portions of the second substrate face each other, the electrode portion of the second substrate is in an equipotential state. In order to fill the display cell on the second substrate with a necessary amount of the particle group or the powder fluid by dispersing the particle group or the powder fluid in the display cell, it is electrically conductive to the unnecessary part of the particle group or the powder fluid. A method for manufacturing an image display panel, wherein a conductive mask is provided, and the conductive mask and the electrode portion on the second substrate are equipotential. Method of manufacturing an image display panel according to claim 1 or 2 the shape of the mask is equal to or larger than the shape of the substrate.   Conductive first protrusions on the surface of the conductive mask facing the second substrate, and conductive second protrusions on the surface of the conductive mask facing the stage on which the second substrate is placed. 4. A particle group or a powdered fluid is filled, wherein the first protrusion is electrically connected to the electrode portion on the second substrate and the second protrusion is electrically connected to the stage. A method for producing an image display panel as described in 1. The method for manufacturing an image display panel according to claim 1 , wherein a conductive mask is connected to the ground. Method of manufacturing an image display panel according to any one of claims 1 to 5, characterized in that connecting the electrode portion on the second substrate to the ground.

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