JP2010262309A - Production method for image display unit and image display unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of fabricating image display device capable of highly retaining bonding strength between barrier walls and a substrate such that a particle or powder fluid leaks to the outside. <P>SOLUTION: The method of fabricating an image display device including an image display panel, having one or more image display elements separated by the barrier walls from each other, in each of which a particle group or the powder fluid, is enclosed between a transparent substrate and a counter substrate, and an electric field is applied to the particle group or the powder fluid to move the particle or the powder fluid and display an image includes a process of forming the barrier walls, on one side substrate of the transparent substrate and the counter substrate; a process of applying an adhesive on the top ends of the barrier walls through screen-printing; a process of semi-curing the adhesive applied by screen-printing; a process of filling the particle group or the powder fluid into spaces constituting the image display elements and separated by the barrier walls; a process of removing the unnecessary particle group or the powder fluid remaining on the semi-cured adhesive on the barrier walls; and a process of bonding the barrier walls to the other side substrate of the transparent substrate and the counter substrate via the semi-cured adhesive to provide the image display panel. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention provides a method for manufacturing an image display device including an image display plate capable of repeatedly displaying and erasing an image with the movement of a particle group using electrostatic force or the movement of a powder fluid.

  As an image display device that replaces a liquid crystal (LCD), an image display device (display) using a technique such as an electrophoretic method, an electrochromic method, a thermal method, or a two-color particle rotation method has been proposed. These image display devices are considered as next-generation inexpensive display devices because of their advantages such as a wide viewing angle close to that of ordinary printed materials, low power consumption, and memory function compared to LCDs. Therefore, it is expected to expand to displays for portable terminals, electronic paper, and the like.

  Recently, an electrophoretic method has been proposed in which a dispersion composed of dispersed particles and a colored solution is microencapsulated and disposed between opposing substrates. However, the electrophoresis method has a problem that the response speed is slow due to the viscous resistance of the liquid because the particles migrate into the liquid. In addition, since particles having a high specific gravity such as titanium oxide are dispersed in a solution having a low specific gravity, there is a problem that they are liable to settle, it is difficult to maintain the stability of the dispersed state, and the stability of image repetition is lacking. Even with microencapsulation, the cell size is reduced to the microcapsule level, and such defects are hardly made to appear, and the essential problems are not solved.

  In contrast to the electrophoresis method using the behavior in the solution as described above, a method in which the conductive particles and the charge transport layer are incorporated in a part of the substrate without using the solution has been proposed (for example, non-patent document). 1). This method has a problem in that the structure for arranging the charge transport layer and further the charge generation layer is complicated, and it is difficult to release the charge from the conductive particles to a certain degree and the stability is insufficient.

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 order to solve the above problems, two types of dry and fast response speed, simple structure, inexpensive and excellent stability as an image display device having different colors and charging characteristics between a transparent substrate and a counter substrate One or more particles separated from each other by partition walls that enclose the particle group or powder fluid and apply an electric field to the particle group or powder fluid from two types of electrodes with different potentials to move the particles or powder fluid and display an image. There is known a dry-type image display device including an image display plate having the image display element. In this image display device, an image display element is formed by disposing a partition wall between a transparent substrate and a counter substrate.

  In the image display apparatus having the above-described configuration, the partition wall is conventionally arranged by positioning the partition wall between the transparent substrate and the counter substrate, and then applying a sealing agent to the corners of the substrate and the partition wall. It was. Therefore, even if there is sufficient strength when the glass substrate is used as the transparent substrate or the counter substrate, sufficient bonding strength can be obtained when using other transparent resins. There was no problem. Therefore, the outflow of particles or powder fluid could not be completely eliminated.

  An object of the present invention is to solve the above-mentioned problems, and in a method for manufacturing an image display device that is dry, has a fast response speed, has a simple structure, is inexpensive, and has excellent stability, and further increases the bonding strength between the partition wall and the substrate. It is an object of the present invention to provide a method of manufacturing an image display device that can be maintained and does not allow particles or powdered fluid to go outside.

  In the method for manufacturing an image display device according to the present invention, a particle group or powder fluid is sealed between a transparent substrate and a counter substrate, and an electric field is applied to the particle group or powder fluid to move the particle or powder fluid to display an image. An image display device comprising an image display panel having one or more image display elements separated from each other by a partition, wherein the partition is formed on one of the transparent substrate and the counter substrate, Adhesive is screen-printed on the tip of the partition wall, the screen printed adhesive is semi-cured, and the space constituting the image display element isolated by the partition wall is filled with particles or powder fluid, and the semi-cured adhesion on the partition wall An unnecessary particle group or powder fluid remaining on the agent is removed, and the partition wall and the transparent substrate and the other substrate of the counter substrate are joined through a semi-cured adhesive to obtain an image display panel. That It is an butterfly.

  Further, as a preferred example of the method for manufacturing an image display device according to the present invention, after fixing the partition wall and the other substrate through an adhesive, a substrate for making the atmosphere between the transparent substrate and the counter substrate uniform. In some cases, a sealant is applied to the outermost peripheral portion of the substrate and a circuit for displaying an image is connected to the electrode to form a module.

  Furthermore, the image display device of the present invention is manufactured by the above-described method for manufacturing an image display device.

  According to the present invention, when using an adhesive for joining the partition wall and the substrate, by applying the adhesive by screen printing, the adhesive can be applied only between the partition wall and the substrate, Deterioration of element characteristics caused by applying an adhesive to the display surface of the substrate can be eliminated, and display characteristics are not adversely affected. Further, in addition to the above effects, particles after screen printing, which were generated because the adhesive after screen printing was a fluid in the past, were made by semi-curing the adhesive after screen printing and eliminating the tackiness. This eliminates the problem of inability to enclose a group or powdered fluid or removal of particles or powdered fluid on a partition wall, and enables encapsulation of particles or powdered fluid into an image display element or removal of particles or powdered fluid on a partition wall. Can be.

(A)-(c) is a figure which shows the structure of an example in the image display element of the image display board which comprises the image display apparatus of this invention, respectively, and its display drive principle. It is a figure for demonstrating the point of the screen printing in this invention. (A), (b) is a figure for demonstrating an example of the screen printing of the adhesive agent in this invention, respectively. (A)-(c) is a figure for demonstrating an example of the manufacturing method of the image display apparatus which concerns on the reference example of this invention, respectively. (A)-(c) is a figure for demonstrating an example of the manufacturing method of the image display apparatus which concerns on the reference example of this invention, respectively. (A)-(d) is a figure for demonstrating an example of the manufacturing method of the image display apparatus which concerns on the Example of this invention, respectively. It is a figure for demonstrating an example of the measuring apparatus for measuring the surface potential of particle | grains in this invention.

FIGS. 1A to 1C are views showing an example of the configuration of an image display element of an image display panel constituting the image display device of the present invention and the display driving principle thereof. In the example shown in FIGS. 1A to 1C, 1 is a transparent substrate, 2 is a counter substrate, 3 is a display electrode, 4 is a counter electrode, 5 is negatively chargeable particles (or powder fluid), and 6 is positively charged. The active particles (or powder fluid), 7 is a partition wall.
In the example shown in FIG. 1A, a negatively charged particle 5 and a positively charged particle 6 (or a solid substance in a gas is stable as a dispersoid between the opposing substrates (the transparent substrate 1 and the opposing substrate 2). A state in which a negatively chargeable powder fluid 5 and a positively chargeable powder fluid 6) exhibiting high fluidity in an aerosol state floating in the state of FIG. In this state, when a voltage is applied so that the display electrode 3 side is at a low potential and the counter electrode 4 side is at a high potential, as shown in FIG. ) 6 moves to the display electrode 3 side, and the negatively chargeable particles (or powder fluid) 5 moves to the counter electrode 4 side. In this case, the display surface viewed from the transparent substrate 1 side looks like the color of the positively charged particles (or powder fluid) 6. Next, when the potential is switched and a voltage is applied so that the display electrode 3 side is at a high potential and the counter electrode 4 side is at a low potential, as shown in FIG. The powdered fluid) 5 moves to the display electrode 3 side, and the positively charged particles (or powdered fluid) 6 moves to the counter electrode 4 side. In this case, the display surface viewed from the transparent substrate 1 side looks like the color of the negatively charged particles (or powder fluid) 6.

  Between FIG. 1 (b) and FIG. 1 (c), it is possible to repeatedly display only by reversing the potential of the power source, and the color can be reversibly changed by reversing the potential of the power source in this way. . The color of the particle group or the powder fluid can be arbitrarily selected. For example, the negatively charged particles (or powder fluid) 5 is white and the positively charged particles (or powder fluid) 6 is black, or the negatively charged particles (or powder fluid) 5 is black, and the positively charged particles If the (or powder fluid) 6 is white, the display is a reversible display between white and black. In this method, each particle group or powdered fluid is once attached to the substrate with a mirror image force, so that the display image is retained for a long time even after the power is turned off, and the memory retainability is good.

  In the present invention, since each charged particle (or powdered fluid) moves in the gas, the response speed of image display is high, and the response speed can be 1 msec or less. Further, unlike the liquid crystal display element, an alignment film, a polarizing plate, and the like are unnecessary, the structure is simple, and the cost and the large area are possible. It is stable against temperature changes and can be used from low to high temperatures. Furthermore, there is no viewing angle, high reflectivity, reflection type, easy to see even in bright places, and low power consumption. It also has memory characteristics and does not consume power when holding images.

  The manufacturing method of the image display device according to the present invention is characterized in that, in manufacturing the image display device shown in FIG. 1 having the above-described configuration, a method of bonding the partition wall 7 forming the image display element and the transparent substrate 1 or the counter substrate 2 is used. It is an improved point.

  First, screen printing of an adhesive in the method for manufacturing an image display device of the present invention will be described. Screen printing itself is the same as a conventionally known method. That is, as shown in FIG. 2 as an example, a substrate on which an adhesive is to be printed, here, for example, a transparent substrate 1 is installed on a base 31 and is made of a stainless mesh, polystyrene mesh or the like that can print a partition pattern. The adhesive 34 is applied and transferred onto the transparent substrate 1 by extruding the adhesive 34 from above using the scraper 33 or the like through the plate making 32.

  3A, the counter substrate 2 and the transparent substrate 1 provided with the partition walls 7 in advance, as shown in FIG. 3B, the partition walls 7 on the surface of the transparent substrate 1 and The adhesive 34 can be screen-printed at the opposite position. In this example, the adhesive is screen-printed on the transparent substrate 1, but when the partition wall 7 is previously provided on the transparent substrate 1, when the adhesive 34 is screen-printed on the counter substrate 2, When screen-printing the adhesive 34 on the tip, screen printing can be performed in the same manner as in the above-described example.

  Next, a method of joining the image display panels using the screen printing described above, which is a feature of the present invention, will be described with reference to the first reference example, the second reference example, and the first example.

(1) Regarding the first reference example using the particle group:
FIGS. 4A to 4C are views for explaining an example of a method for manufacturing an image display device according to the first reference example of the present invention. First, as shown in FIG. 4A, a partition wall 7 is formed in a predetermined pattern on one of the transparent substrate 1 and the counter substrate 2, here the transparent substrate 1, and the image display is separated by the partition wall 7. The space constituting the element 41 is filled with a particle group 42 composed of a black particle group 42B and a white particle group 42W having different charging characteristics. As a method of filling the particle group 42, a method of spraying the particle group 42 on the counter substrate 2 using gravity or air current, a method of flying the particle group 42 using charging, or the like can be used. Thereafter, the unnecessary particle group 42 remaining on the partition walls 7 is removed to prepare a particle-encapsulated substrate shown in FIG. As a removal method of the particle group 42, a removal method using an adhesive roll, a removal method using an electric force, a removal method of blowing away unnecessary particle groups 42 using an air flow, or the like can be used.

  Next, as shown in FIG. 4B, the adhesive 34 is screen-printed on the other substrate of the transparent substrate 1 and the counter substrate 2, here the surface of the counter substrate 2, the position facing the partition wall 7. Then, as shown in FIG. 7C, the partition wall 7 and the other substrate, here the counter substrate 2, are bonded via an adhesive 34. Thereafter, the adhesive 34 is cured, whereby an image display panel can be obtained.

  According to the first reference example, when the adhesive 34 is used to join the partition wall 7 and the counter substrate 2, the adhesive 34 is applied by screen printing, so that the partition wall 7 and the counter substrate 2 can be applied. Adhesive 34 can be applied only in between, the deterioration of element characteristics caused by applying adhesive 34 to the display surface of the substrate can be eliminated, and display characteristics are not adversely affected.

(2) Regarding the second reference example using the particle group:
FIGS. 5A to 5C are views for explaining an example of a method for manufacturing an image display device according to a second reference example of the present invention. First, as shown in FIG. 5A, an image display in which a partition wall 7 is formed in a predetermined pattern on one of the transparent substrate 1 and the counter substrate 2, here, the transparent substrate 1, and is separated by the partition wall 7. The space constituting the element 41 is filled with a particle group 42 composed of a black particle group 42B and a white particle group 42W having different charging characteristics. Thereafter, a particle-encapsulated substrate in which the particle group 42 is installed on the partition wall 7 shown in FIG. 5A is prepared in a state where the particle group 42 remaining on the partition wall 7 is left.

  Next, as shown in FIG. 5B, the adhesive 34 is screen-printed on the other substrate of the transparent substrate 1 and the counter substrate 2, here the surface of the counter substrate 2, at a position facing the partition wall 7. Then, as shown in FIG. 5C, the partition wall 7 and the other substrate, here the counter substrate 2, are bonded via an adhesive 34 and a particle group 42. Thereafter, the adhesive 34 is cured, whereby an image display panel can be obtained.

  According to the second reference example, as in the first reference example, when the adhesive 34 is used for joining the partition wall 7 and the counter substrate 2, the adhesive 34 is applied by screen printing. The adhesive 34 can be applied only between the partition wall 7 and the counter substrate 2, the deterioration of the element characteristics caused by applying the adhesive 34 to the display surface of the substrate can be eliminated, and the display characteristics are adversely affected. There is nothing. Further, in the second reference example, in addition to the above-described common effect, the adhesion process is performed with the particle group 42 left on the partition wall 7, so that the gas generated when the adhesive is cured is generated inside the image display element. It is possible to prevent being pressurized and being sealed.

(3) Regarding the first embodiment using particle groups:
FIGS. 6A to 6D are views for explaining an example of the method for manufacturing the image display device according to the first embodiment of the present invention. First, as shown in FIG. 6A, a partition wall 7 is formed in a predetermined pattern on one of the transparent substrate 1 and the counter substrate 2, here the transparent substrate 1, and an adhesive 34 is formed at the tip of the partition wall 7. Screen print. Next, as shown in FIG. 6B, the adhesive 34 provided at the tip of the partition wall 7 is semi-cured. By semi-curing the liquid adhesive 34, the adhesive 34 loses its tackiness, but has sufficient tackiness for fixing to the substrate. Here, the semi-curing of the adhesive 34 can be performed by applying ultraviolet rays (UV) or heat to the adhesive 34 for a predetermined time according to the properties thereof.

  Next, as shown in FIG. 6C, a particle group 42 composed of a black particle group 42B and a white particle group 42W having different charging characteristics is provided in the space constituting the image display element 41 separated by the partition wall 7. Fill. Thereafter, the unnecessary particle group 42 remaining on the partition walls 7 is removed to prepare a particle-encapsulated substrate shown in FIG. Then, as shown in FIG. 6 (d), the partition wall 7 and the other substrate, here the counter substrate 2, are bonded via an adhesive 34. Thereafter, the adhesive 34 is cured, whereby an image display panel can be obtained.

  According to the first embodiment, similarly to the first reference example, when the adhesive 34 is used for joining the partition wall 7 and the counter substrate 2, the adhesive 34 is applied by screen printing. The adhesive 14 can be applied only between the partition wall 7 and the counter substrate 2, the deterioration of the element characteristics caused by applying the adhesive 14 to the display surface of the substrate can be eliminated, and the display characteristics are adversely affected. There is nothing. Further, in the first embodiment, in addition to the above-mentioned common effects, the adhesive after screen printing has conventionally been a fluid by removing the adhesive by semi-curing the adhesive after screen printing. This eliminates the problem that the particle groups cannot be enclosed after screen printing or the particle groups on the partition walls cannot be removed, and enables the encapsulation of the particle groups in the image display element and the removal of the particle groups on the partition walls. be able to.

  In the present invention, after fixing the partition wall and the other substrate with an adhesive as described above, the outermost peripheral portion of the substrate is made uniform in order to make the atmosphere between the transparent substrate 1 and the counter substrate 2 uniform. It is also possible to apply a sealant and connect a circuit for displaying an image with an electrode to form a module. In this case, the circuit used for displaying an image can be modularized, which is preferable.

  As mentioned above, although the 1st reference example, the 2nd reference example, and the 1st example demonstrated the manufacturing method of the image display apparatus using a particle group, also in the manufacturing method of the image display apparatus using powder fluid, The image display device can be manufactured according to the same first reference example, second reference example, and first example only by replacing the particle group with the powder fluid.

  Hereinafter, each component of the image display device of the present invention will be described in detail in the order of the particle group, the powder fluid, and each component.

First, the particle group will be described.
The particle group used for display in the image display device of the present invention may be any negative or positively charged colored particle group that can fly and move by Coulomb force. Groups are preferred. The particle group is of a single color, and white or black particle groups are preferably used. The average particle size of the particle group is preferably from 0.1 to 50 μm, particularly preferably from 1 to 30 μm. If the average particle diameter is smaller than this range, the charge density of the particles is too large and the mirror image force to the electrode or substrate is too strong, and the memory property is good, but the followability when the electric field is reversed is poor. On the contrary, if the average particle diameter is larger than this range, the followability is good, but the memory property is poor.

  A method of charging the particles negatively or positively is not particularly limited, and a method of charging the particles such as a corona discharge method, an electrode injection method, and a friction method is used. The charge amount of particles naturally depends on the measurement conditions, but the charge amount of particles in the image display device is almost dependent on the initial charge amount, contact with the substrate, contact with different types of particles, and charge decay with elapsed time. In particular, it has been found that the “contact with different types of particles”, that is, the saturation value of the charging behavior associated with the contact between two particles is the dominant factor. Therefore, it is important to know the difference in charging characteristics between the two particles, that is, the difference in work function, in terms of the charge amount, but this is difficult by simple measurement.

  As a result of intensive studies, the present inventors have found that the same carrier can be used in the blow-off method to perform relative evaluation by measuring the charge amount of each particle. By defining this by the surface charge density, the image can be obtained. It has been found that the charge amount of particles suitable as a display device can be predicted.

  Although the measurement method will be described in detail later, the charge amount per unit weight of the particles can be measured by bringing the particles and carrier particles into sufficient contact by the blow-off method and measuring the saturation charge amount. Then, the surface charge density of the particles can be calculated by separately obtaining the particle diameter and specific gravity of the particles.

In the image display device, the particle diameter of the particles used is small and the influence of gravity is so small that it can be ignored. Therefore, the specific gravity of the particles does not affect the movement of the particles. However, regarding the charge amount of the particles, even if the average charge amount per unit weight is the same for the particles having the same particle diameter, the charge amount to be held when the specific gravity of the particles is two times different will be two times different. Therefore, it was found that the charging characteristics of the particles used in the image display device are preferably evaluated by the surface charge density (unit: μC / m ² ) that is independent of the specific gravity of the particles.

  When there is a sufficient difference in surface charge density between the particles, the two kinds of particles retain the charge amounts of different polarities due to contact with each other, and retain the function of moving by the electric field.

  Here, the surface charge density needs to have a certain difference in order to make the two particles have different charging polarities, but the larger the surface charge density, the better. In image display devices based on particle movement, when the particle size of the particle is large, the electric image force tends to be a factor that mainly determines the flying electric field (voltage) of the particle, so this particle is moved with a low electric field (voltage). For this purpose, a lower charge amount is better. In addition, when the particle size of the particle is small, non-electric forces such as intermolecular force and liquid crosslinking force are often determinants of the flying electric field (voltage), so this particle is moved with a low electric field (voltage). Therefore, a higher charge amount is better. However, since this greatly depends on the surface properties (material / shape) of the particles, it cannot be generally defined by the particle diameter and the charge amount.

In the case of particles having an average particle diameter of 0.1 to 50 μm, the present inventors have an absolute value of the difference in surface charge density of two types of particles measured by the blow-off method using the same carrier, of 5 to 150 μC / m ^2. It was found that the particles can be used as an image display device.

  The blow-off measurement principle and method are as follows. In the blow-off method, a mixture of powder and carrier is placed in a cylindrical container with nets at both ends, high pressure gas is blown from one end to separate the powder and carrier, and only the powder is removed from the mesh opening. Blow off. At this time, the charge amount equal to the charge amount taken away from the container by the powder remains on the carrier. All of the electric flux due to this charge is collected by the Faraday cage, and the capacitor is charged by this amount. Therefore, by measuring the potential across the capacitor, the charge amount Q of the powder can be obtained as Q = CV (C: capacitor capacity, V: voltage across the capacitor).

TB-200 manufactured by Toshiba Chemical Co. was used as a blow-off powder charge measuring device. In the present invention, F963-2535 manufactured by Powdertech Co., Ltd. was used as a carrier, and the charge density (unit: μC / m ² ) per unit surface area in each case was measured.

Since the particles need to retain their charged electric charge, insulating particles having a volume resistivity of 1 × 10 ¹⁰ Ω · cm or more are preferable, and insulating particles having 1 × 10 ¹² Ω · cm or more are particularly preferable.

  The particles in the image display device of the present invention are more preferably particles having a slow charge decay property evaluated by the method described below. That is, the particles are separately formed into a film having a thickness of 5 to 100 μm by pressing, heat melting, casting, or the like, and a voltage of 8 KV is applied to a corona discharger disposed with a 1 mm interval from the film surface. Corona discharge is generated to charge the surface, and the change in surface potential is measured and judged. In this case, it is desirable to select and prepare the particle constituent material so that the maximum value of the surface potential after 0.3 seconds is greater than 300V, preferably greater than 400V.

  The measurement of the surface potential can be performed, for example, with the apparatus shown in FIG. 7 (CRT2000 manufactured by QEA). In the case of this apparatus, both ends of the roll shaft on which the above-described film is arranged are held by the chuck 51, and a measuring unit in which a small scorotron discharger 52 and a surface potential meter 53 are separated from each other by a predetermined distance is provided on the film. A surface charge is applied by moving the measuring unit at a constant speed from one end of the roll shaft to the other end while keeping the roll shaft stationary with a 1 mm gap from the surface of the roll. A method for measuring the surface potential is preferably employed. The measurement environment is a temperature of 25 ± 3 ° C. and a humidity of 55 ± 5 RH%.

The particles in the image display apparatus of the present invention may be composed of any material as long as characteristics such as charging performance are satisfied. For example, it can be formed from a resin, a charge control agent, a colorant, an inorganic additive, or the like, or a colorant alone.
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 Examples include acrylic resin, polyolefin resin, butyral resin, vinylidene chloride resin, melamine resin, phenol resin, fluororesin, polycarbonate resin, polysulfone resin, polyether resin, polyamide resin, etc. Therefore, acrylic urethane resin, acrylic silicone resin, acrylic fluororesin, acrylic urethane silicone resin, acrylic urethane fluororesin, fluororesin, and silicone resin are suitable. Two or more kinds can be mixed.

  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 black pigments include carbon black, copper oxide, manganese dioxide, aniline black, and activated carbon.
Yellow pigments include yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral first yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa yellow G, Hansa yellow 10G, benzidine yellow G, benzidine yellow GR, quinoline There are yellow rake, permanent yellow NCG, tartrage rake and so on.
Examples of the orange pigment include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, indanthrene brilliant orange RK, benzidine orange G, and indanthrene brilliant orange GK.

Examples of red pigments 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, There are Alizarin Lake and Brilliant Carmine 3B.
Examples of purple pigments include manganese purple, first violet B, and methyl violet lake.
Examples of blue pigments include bitumen, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated, first sky blue, and induslen blue BC.
Examples of the green pigment include chrome green, chromium oxide, pigment green B, malachite green lake, final yellow green G, and the like.
Examples of white pigments 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.
Furthermore, various dyes such as basic, acidic, disperse, and direct dyes include nigrosine, methylene blue, rose bengal, quinoline yellow, and ultramarine blue.
These colorants can be used alone or in combination.
In particular, carbon black is preferable as the black colorant, and titanium oxide is preferable as the white colorant.
The production example of the particles is not particularly limited. For example, a kneading / pulverization method and a polymerization method according to the case of producing an electrophotographic toner can be used. Further, a method of coating the surface of the inorganic or organic pigment powder with a resin, a charge control agent or the like is also used.

The distance between the transparent substrate 1 and the counter substrate 2 in the image display device of the present invention is adjusted to 10 to 5000 μm, preferably 30 to 500 μm, as long as the particles can fly and maintain the contrast.
The particle filling amount (volume occupation ratio) is preferably filled so as to be a volume that occupies 5 to 70%, preferably 5 to 60%, with respect to the space volume between the substrates.

Further, in order to further improve the repeated durability here, it is effective to manage the stability of the resin constituting the particles, particularly the water absorption rate and the solvent insolubility rate.
The water absorption of the resin constituting the particles to be sealed between the substrates is preferably 3% by weight or less, particularly preferably 2% by weight or less. The water absorption is measured according to ASTM D570, and the measurement conditions are 23 ° C. and 24 hours.
Regarding the solvent insolubility of the resin constituting the particles, the solvent insolubility of the particles represented by the following relational formula is preferably 50% or more, particularly 70% or more.
Solvent insolubility (%) = (B / A) × 100
(However, A represents the weight of the resin before dipping in the solvent, and B represents the weight after dipping the resin in a good solvent at 25 ° C. for 24 hours.)
If the solvent insolubility is less than 50%, bleeding may occur on the particle surface during long-term storage, affecting the adhesion with the particle and hindering the movement of the particle, which may impair the image display durability.
The solvent (good solvent) used for measuring the solvent insolubility is methyl ethyl ketone, etc. for fluororesins, methanol, etc. for polyamide resins, methyl ethyl ketone, toluene, etc. for acrylic urethane resins, acetone, isopropanol, etc. for melamine resins, silicone resins, etc. In this case, toluene or the like is preferable.

Moreover, it is preferable that the particles are spherical and have uniform and uniform particle diameters.
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 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 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 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 having different charging characteristics move closer to each other, so it is preferable that the particle sizes are close to each other and the particles can move easily. Is in 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. .
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.

Next, the powder fluid used in 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 panel of the present invention. To do.

  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 sheets, 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 powdered fluid is a substance in an intermediate state between the fluid and the particle, which exhibits fluidity by itself without borrowing the force of gas or liquid. This powder fluid can be in an aerosol state in particular, and the image display panel of the present invention is used in a state where a solid substance in the gas floats relatively stably as a dispersoid.

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.

Further, in the image display panel of the present invention, it is preferable that the change in the apparent volume of the powder fluid with time satisfies the following formula.
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 addition, the image display panel of the present invention preferably has a time change V ₁₀ / V ₅ of the apparent volume of the powder fluid larger than 0.85, particularly 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 becomes difficult to control the display, and if it is larger than 20 μm, it is possible to display but the concealment rate is lowered and it is difficult to make the device thin. 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.

Examples of the colorant include basic and acidic dyes such as nigrosine, methylene blue, quinoline yellow, and rose bengal.
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, cobalt blue, cobalt green, cobalt violet, iron oxide, carbon black, manganese ferrite black, cobalt ferrite black, copper powder, and aluminum powder.
These colorants and inorganic additives can be used alone or in combination. In particular, carbon black is preferable as the black colorant, and titanium oxide is preferable as the white colorant.

  However, even if such a material is kneaded and coated without any ingenuity, a powder fluid that shows an aerosol state cannot be produced. The production method of the powder fluid showing the aerosol state is not clear, but is exemplified as follows.

  First, it is appropriate to fix inorganic fine particles having an average particle diameter of 20 to 100 nm, preferably 20 to 80 nm, to the surface of the particulate material constituting the powder fluid. The inorganic fine particles are suitably composed of two or more types of fine particles. Furthermore, it is appropriate that the inorganic fine particles are treated with silicone oil. Here, examples of the inorganic fine particles include silicon dioxide (silica), zinc oxide, aluminum oxide, magnesium oxide, cerium oxide, iron oxide, and copper oxide. The method of fixing the inorganic fine particles is important. For example, using a hybridizer (manufactured by Nara Machinery Co., Ltd.), mechanofusion (manufactured by Hosokawa Micron Co., Ltd.) or the like, under certain limited conditions (for example, processing time) ), A powder fluid showing an aerosol state can be produced.

Here, in order to further improve the repeated durability, it is effective to manage the stability of the resin constituting the powder fluid, particularly the water absorption rate and the solvent insolubility rate. The water absorption rate of the resin constituting the powder fluid to be sealed between the sheets is preferably 3% by weight or less, particularly preferably 2% by weight or less. The water absorption is measured according to ASTM-D570, and the measurement condition is 23 ° C. for 24 hours. Regarding the solvent insolubility of the resin constituting the powder fluid, the solvent insolubility of the powder fluid represented by the following relational expression is preferably 50% or more, particularly 70% or more.
Solvent insolubility (%) = (B / A) × 100
(However, A represents the weight of the resin before dipping in the solvent, and B represents the weight after dipping the resin in a good solvent at 25 ° C. for 24 hours.)

  If the solvent insolubility is less than 50%, bleeding may occur on the surface of the particulate material during long-term storage, affecting the adhesion to the powder fluid and hindering the movement of the powder fluid, which may hinder the durability of image display. is there. The solvent (good solvent) for measuring the solvent insolubility is methyl ethyl ketone, etc. for fluororesins, methanol, etc. for polyamide resins, methyl ethyl ketone, toluene, etc. for acrylic urethane resins, acetone, isopropanol, etc. for melamine resins, silicone resins, etc. In this case, toluene is preferable.

Next, each component will be described.
First, the substrate will be described.
The transparent substrate 1 is a substrate on which the color of a particle group 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 presence or absence of flexibility is appropriately selected depending on the application. For example, it is not flexible for applications such as materials that are flexible for applications such as electronic paper, mobile phones, PDAs, and portable devices such as notebook computers. Material is used.

Examples of the substrate material include polymer sheets such as polyethylene terephthalate, polyethersulfone, polyethylene, and polycarbonate, and inorganic sheets such as glass and quartz.
The substrate thickness is suitably 2 to 1100 μm, preferably 5 to 700 μm. If it is too thin, it will be difficult to maintain strength and spacing uniformity between the substrates, and if it is too thick, the display function will be sharp and the contrast will decrease. Especially in the case of electronic paper applications.

An electrode may be provided on the substrate as necessary.
When the substrate is not provided with an electrode, an electrostatic latent image is provided on the external surface of the substrate, and a colored particle group or powder fluid charged with predetermined characteristics is applied by an electric field generated according to the electrostatic latent image. By attracting or repelling the substrate, the particle group or powder fluid arranged corresponding to the electrode potential is visually recognized from the outside of the display device through the transparent substrate. This electrostatic latent image is formed by transferring an electrostatic latent image formed by an ordinary electrophotographic system using an electrophotographic photosensitive member onto the substrate of the image display device of the present invention, or by ion flow. An electrostatic latent image can be formed directly on the substrate.

When an electrode is provided on the substrate, by applying an external voltage to the electrode part, an electric field generated at each electrode position on the substrate causes the colored particles or powder fluid charged to a predetermined property to attract or repel, This is a method of visually recognizing a particle group or powder fluid arranged corresponding to an electrostatic latent image from the outside of the display device through a transparent substrate.
The electrode provided on the transparent substrate side is formed of a conductive material that is transparent and can be patterned, and examples include metals such as indium oxide and aluminum, and conductive polymers such as polyaniline, polypyrrole, and polythiophene. Examples of the forming method include vacuum deposition and coating. The thickness of the electrode is not particularly limited as long as the conductivity can be secured and the light transmittance is not affected, and is preferably 3 to 1000 nm, preferably 5 to 400 nm.
The electrode provided on the back substrate side is formed of a conductive material that does not need to be transparent and can be patterned. For example, metals such as indium oxide, aluminum, gold, silver, copper, polyaniline, polypyrrole, polythiophene Examples of the forming method such as vacuum deposition and coating can be given. The thickness of the electrode is not particularly limited as long as the conductivity can be secured and the light transmittance is not affected, and is preferably 3 to 1000 nm, preferably 5 to 400 nm.
In this case, the external voltage input may be superimposed with direct current or alternating current.

The shape of the partition wall 7 of the present invention is appropriately set appropriately depending on the size of the particles involved in the display or the size of the powder fluid, and is not limited to a specific shape, but the partition wall width is 2 to 100 μm, preferably 3 to 50 μm The height is adjusted to 2 to 5000 μm, preferably 5 to 500 μm.
The display cells formed by the partition walls made up of these ribs are exemplified by a square shape, a triangular shape, a line shape, a circular shape, and a hexagonal shape as viewed from the substrate plane direction, and the arrangement is exemplified by a lattice shape or a honeycomb shape.
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 walls 7 include a screen printing method, a sand blast method, a photolithography method, and an additive method. Of these, the photolithography method using a resist film is preferably used.

  As is apparent from the above description, according to the present invention, when an adhesive is used for joining the partition wall and the substrate, the adhesive is applied by screen printing, so that only the partition wall and the substrate are bonded. An agent can be applied, deterioration of element characteristics caused by applying an adhesive to the display surface of the substrate can be eliminated, and display characteristics are not adversely affected.

  Therefore, the image display device provided with the image display panel of the present invention includes display units of mobile devices such as notebook computers, PDAs, mobile phones, and handy terminals, electronic papers such as electronic books and electronic newspapers, signboards, posters, and blackboards. It is suitably used for display units for bulletin boards, calculators, home appliances, automobile 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. .

DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Counter substrate 3 Display electrode 4 Counter electrode 5 Negatively charged particle (or powder fluid)
6 Positively charged particles (or powder fluid)
7 Bulkhead 31 Base 32 Plate Making 33 Scraper 34 Adhesive 41 Image Display Element 42 Particle Group 42B Black Particle 42W White Particle 51 Chuck 52 Scorotron Discharger 53 Surface Potential Meter

Claims (3)

  One or more particles separated from each other by a partition wall that encloses the particle group or powder fluid between the transparent substrate and the counter substrate, and applies an electric field to the particle group or powder fluid to move the particle or powder fluid to display an image. A method of manufacturing an image display device including an image display panel having an image display element, wherein a partition is formed on one of the transparent substrate and the counter substrate, and an adhesive is screen printed on a tip of the partition, and the screen Semi-cured printed adhesive, filled with particles or powder fluid into the space that constitutes the image display element isolated by the partition, and left unwanted particles or powder remaining on the semi-cured adhesive on the partition A method for manufacturing an image display device, comprising: removing a fluid, and bonding a partition wall to the other of the transparent substrate and the counter substrate through a semi-cured adhesive to obtain an image display panel.   After fixing the partition wall and the other substrate via an adhesive, a sealant is applied to the outermost peripheral portion of the substrate in order to make the atmosphere between the transparent substrate and the counter substrate uniform, and an image is displayed. The method for manufacturing an image display device according to claim 1, wherein the circuit is connected to an electrode to form a module. An image display device manufactured by the method for manufacturing an image display device according to claim 1.

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