JP4125096B2 - Method for manufacturing electrophoretic display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing an electrophoretic display device that performs display by moving electrophoretic particles in a liquid.
[0002]
[Prior art]
In recent years, with the development of information equipment, the need for low power consumption and thin display devices is increasing, and research and development of display devices that meet these needs are being actively conducted.
[0003]
In particular, liquid crystal display devices are capable of electrically controlling the arrangement of liquid crystal molecules to change the optical characteristics of the liquid crystal, and are actively developed and commercialized as display devices that can meet the above needs. However, these liquid crystal display devices have not yet fully solved the burden on vision caused by the angle at which the screen is viewed, the difficulty of seeing characters on the screen due to reflected light, and the flickering and low luminance of the light source. For this reason, in addition to low power consumption, research on display devices that emphasizes the viewpoint of reducing the burden on vision has been actively studied.
[0004]
Therefore, a reflective display device is expected from the viewpoint of low power consumption and reduction of the burden on the eyes. As one of them, an electrophoretic display that obtains a display effect by applying an electric field to a liquid (hereinafter referred to as a dispersion medium) in which colored particles (hereinafter referred to as electrophoretic particles) are dispersed and moving the particles by an electrophoretic phenomenon. The device is known. Such an apparatus comprises an electrophoretic display panel and its driving means. The electrophoretic display panel includes an electrophoretic display medium sandwiched between a pair of substrates, at least one of which is transparent, and an electric field is applied to the display medium by an electrode provided on one or both of the substrates. It is common to obtain a display effect by changing the distribution of.
[0005]
By the way, since the dispersion medium for dispersing the electrophoretic particles contains a liquid as a main component, it is necessary to prevent outflow and volatilization from the display panel. Therefore, there has been proposed one in which such a dispersion medium is enclosed in a microcapsule. In that case,
-Microcapsules are mainly manufactured by any of the interfacial polymerization method, in situ polymerization method, phase separation method (coacervation method),
-Mix the microcapsule with a binder resin to make a resin composition,
・ Apply the resin composition to the substrate by roll coater method, roll laminator method, screen printing method, spray method, etc.
This method was generally adopted.
[0006]
Note that by using such a microcapsule, an electrophoretic display device that performs multicolor display can be manufactured. For this purpose, it is general to use electrophoretic particles or a dispersion colored in a color different from the electrophoretic particles. Furthermore, a method of manufacturing a multicolor display device by providing a color filter layer used in a liquid crystal display device in the electrophoretic display device has been proposed (for example, see Patent Document 1).
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 2-146019
[Patent Document 2]
JP 2000-035769 A
[Patent Document 3]
JP 11-286113 A
[Patent Document 4]
JP 2001-232178 A
[0008]
[Problems to be solved by the invention]
However, in the microcapsule placement method as described above, it is necessary to prepare in advance (that is, at the stage before placement on the substrate) microcapsules corresponding to the type of display color to be placed. When manufacturing an electrophoretic display panel, the manufacturing process becomes complicated.
[0009]
As a way to avoid such problems,
A method of arranging microcapsules one by one at a predetermined position using an inkjet device (for example, see Patent Document 2),
A method of arranging a display material containing electrophoretic particles in an inkjet apparatus at a predetermined position (for example, see Patent Document 3),
A method of supplying the constituent elements of the microcapsule with an inkjet device (for example, see Patent Document 4)
However, it is technically more difficult to reliably supply microcapsules to a desired position by an ink jet apparatus as the display panel becomes a high-definition display panel. In addition, a large and high-definition display panel needs to arrange a large number of microcapsules at predetermined positions, and the method of supplying microcapsules one by one from a nozzle has a problem that it takes time to manufacture the display panel. Furthermore, in an electrophoretic display device provided with a color filter layer, it is necessary to precisely align the electrodes for driving the microcapsules, the microcapsules to be driven, and the pixels of the color filter sequentially, which is complicated in the manufacturing process. .
[0010]
Accordingly, an object of the present invention is to provide an electrophoretic display device manufacturing method that avoids these problems.
[0011]
[Means for Solving the Problems]
  The present invention has been made in consideration of the above circumstances, and has a first substrate and a second substrate disposed in a state where a predetermined gap is provided, and has electrophoretic particles and a dispersion medium and is disposed in the gap between the substrates. In a method of manufacturing an electrophoretic display device comprising a plurality of microcapsules, and a first electrode and a second electrode arranged so as to sandwich the microcapsules,
  Producing a plurality of microcapsules in which white electrophoretic particles charged to positive polarity and black electrophoretic particles charged to negative polarity are dispersed in the transparent dispersion medium;
  Disposing the plurality of microcapsules on the first substrate;
  Coloring the region in which the microcapsules are disposed;
  Attaching the second substrate to the first substrate and sealing the microcapsules.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 6.
[0013]
As shown in FIG. 1, an electrophoretic display device manufactured by applying the present invention includes a first substrate 1a and a second substrate 1b arranged with a predetermined gap therebetween, and these substrates 1a. , 1b, a plurality of microcapsules 2R, 2G, 2B are arranged. Each microcapsule 2R, 2G, 2B has a plurality of electrophoretic particles (see reference numeral 20 in FIG. 5) and a dispersion medium (see reference numeral 21 in FIG. 5). In addition, when it is necessary to distinguish these microcapsules, it will distinguish by attaching | subjecting code | symbol 2R, 2G, 2B, and when it is not necessary to distinguish, only code | symbol "2" shall be attached | subjected.
[0014]
Further, the first electrode 3a and the second electrode 3b are arranged so as to sandwich the microcapsules 2.
[0015]
[Microcapsule]
The above-described microcapsule 2 is
-Even if it is arranged so as to straddle a plurality of pixels (if one microcapsule is divided into colors corresponding to each pixel)
・ Even if one pixel is arranged,
・ As shown in FIG. 2, even if a plurality of pixels are arranged,
good.
[0016]
Moreover, the particle size of a microcapsule should just be 10 micrometers-200 micrometers, Preferably they are 10 micrometers-100 micrometers, More preferably, they are 20 micrometers-80 micrometers. Further, the obtained microcapsules may be classified as necessary.
[0017]
[Electrophoretic particles]
The electrophoretic particles 20 described above are colored and charged,
-Even if the electrophoretic particles in the same microcapsule are colored in the same color and charged with the same polarity (that is, the electrophoretic particles in the same microcapsule are one type)
-Even if electrophoretic particles colored in one color and charged in one polarity and electrophoretic particles colored in another color and charged in other polarity are mixed in the same microcapsule (that is, the same) 2 types of electrophoretic particles in a microcapsule)
good. That is,
Electrophoretic particles that are positively charged and colored in any color;
Electrophoretic particles that are negatively charged and colored in other colors
May be placed in the same microcapsule 2 and different colors may be displayed by the movement of these electrophoretic particles (details will be described with reference to FIG. 6).
[0018]
The electrophoretic particles 20 may be colored in any color, but only white, black only, or a mixture of white and black, red (R), green (G), blue (B The color (system) arbitrarily selected from four colors (system), yellow (Y), magenta (M), cyan (C), and black (K) arbitrarily selected from the three colors.
[0019]
The electrophoretic particles are not particularly limited as long as they are known, such as organic materials such as polymer fine particles, inorganic materials such as pigments, mixed materials thereof, and organic-inorganic hybrid materials. However, pigments such as white, black, R, G, B, C, M, and Y are preferable. As white particles, titanium oxide, aluminum oxide, zinc oxide, lead oxide, tin oxide, magnesium sulfate, silica, etc. can be used, and as black particles, carbon black, aniline black, manganese ferrite black, cobalt ferrite black, etc. Can be used. Each primary color pigment includes cadmium red, quinacridone red, lake red, brilliant carmine, madder lake and other red pigments, diamond green lake, phthalocyanine green, pigment green B and other green pigments, cobalt blue, Victoria blue lake, phthalocyanine blue. Blue pigments such as Fast Sky Blue, yellow pigments such as Hansa Yellow, Cadmium Yellow, Fast Yellow, Disazo Yellow, Titanium Yellow, Yellow Iron Oxide, Yellow Lead, Hansa Yellow, Disazo Yellow and the like can be used.
[0020]
Alternatively, the surface of the particle may be used as an electrophoretic particle by covering it with a known resin or a known charge controlling material. The particle size of the electrophoretic particles is preferably 0.01 to 10 μm, more preferably 0.1 to 6 μm. Furthermore, the concentration of the electrophoretic particles is preferably 1 to 30% by mass.
[0021]
[Dispersion medium]
The dispersion medium 21 may be transparent or colored, but when colored, the dispersion medium 21 needs to have a different color from the electrophoretic particles.
[0022]
Highly insulating and colorless transparent dispersion media include aromatic hydrocarbons such as toluene, xylene, ethylbenzene, dodecylbenzene, aliphatic hydrocarbons such as hexane, cyclohexane, kerosene, normal paraffin, isoparaffin, chloroform, dichloromethane, penta Halogenated hydrocarbons such as chloroethane, 1,2-dibromoethane, 1,1,2,2-tetrabromoethane, trichloroethylene, tetrachloroethylene, trifluoroethylene, tetrafluoroethylene, various natural or synthetic oils, etc. can be used These may be used alone or in combination of two or more. In addition, a charge adjusting agent, a dispersing agent, a lubricant, a stabilizer and the like may be added to the dispersion medium as necessary.
[0023]
When coloring the dispersion medium, an oil-soluble dye can be used. These oil-soluble dyes include azo dyes, anthraquinone dyes, quinoline dyes, nitro dyes, nitroso dyes, penoline dyes, phthalocyanine dyes, metal complex dyes, nafur dyes, benzoquinone dyes, cyanine dyes, indigo dyes, and quinoimine dyes. Dyes are preferred, and these may be used in combination.
[0024]
For example, the following oil-soluble dyes can be mentioned. Bali First Yellow (1101, 1105, 3108, 4120), Oil Yellow (105, 107, 129, 3G, GGS), Bali First Red (1306, 1355, 2303, 3304, 3306, 3320), Oil Pink 312, Oil Scarlet 308, Oil Violet 730, Bali First Blue (1501, 1603, 1605, 1607, 2606, 2610, 3405), Oil Blue (2N, BOS, 613), Macrolex Blue RR, Sumiplast Green G, Oil Green (502 , BG) and the like, and the concentration of the oil-soluble dye is preferably 0.3 to 3.5% by mass.
[0025]
[Microcapsule shell (wall portion indicated by reference numeral 23 in FIG. 5)]
Examples of the material (wall material) that forms the shell (wall) of the microcapsule include a colorless and transparent material that can coat the electrophoretic particles and the dispersion medium as cores and sufficiently transmit light. Examples of wall materials include urea resin, urea-formaldehyde resin, melamine-formaldehyde resin, polyurethane, polyurea-polyurethane, polyamide, polyester, polysulfonamide, polycarbonate, polysulfinate, epoxy, acrylic ester, methacrylic ester, acetic acid Examples thereof include vinyl and gelatin. Further, a dye or pigment that dissolves or disperses in the wall material may be added.
[0026]
Moreover, you may add surfactant as needed. As the surfactant, a polymeric surfactant is preferable, and for example, styrene-maleic anhydride, ethylene-maleic anhydride, or the like can be used. The concentration of the surfactant is preferably 1 to 10% by mass.
[0027]
In addition to these, microcapsules are produced by any one of the aforementioned interfacial polymerization method, in situ polymerization method, and phase separation method (coacervation method).
[0028]
[Gap member]
Further, since it is not preferable that the microcapsule 2 moves (displaces) along the substrate surface, a gap member 4 is arranged in the gap between the microcapsule 2 and the microcapsule 2 as shown in FIG. It is preferable to prevent the capsule 2 from being displaced. Various materials (solid or liquid) can be used for the gap members 4R, 4G, and 4B, but it is preferable to use a resin.
[0029]
[Image display method]
In the present embodiment, the display is performed by moving the electrophoretic particles 20 in the microcapsule based on applying a voltage between the first electrode 3a and the second electrode 3b.
[0030]
For example, an arbitrary character may not be freely displayed on the electrophoretic display device, but a specific character may be switched between a display state and a non-display state. FIG. 4 shows an example in which the character string “A BC” is displayed. This character string is originally colored (coated) in the above-mentioned “region where the microcapsule 2 is disposed”, and can be displayed or hidden by moving the electrophoretic particles. In such a case, the first electrode 3a and the second electrode 3b are common, and the electrophoretic particles of each pixel may be moved in the same direction, and these electrodes are formed in an independent shape for each pixel or controlled independently. There is no need. The displayed character string can be freely set according to the color scheme of the “area where the microcapsule 2 is arranged”. For example, gradation and multicolor display are possible. It is also possible to display by driving all the microcapsules on the non-character part by arranging electrodes in the non-character part. Such an embodiment can be used as a display device for advertising media and POP (Point Of Purchase advertising).
[0031]
Next, a case where the electrophoretic particles placed in the microcapsule are of one type (that is, the case where all the electrophoretic particles are colored in the same color and charged with the same polarity) will be described.
[0032]
When an electric field is applied in the direction indicated by symbol E in FIG. 5 (a), the electrophoretic particles 20 move to the upper side of the microcapsule 2, and when an electric field is applied in the direction indicated by symbol E in FIG. The particles 20 move to the lower side of the microcapsule 2. If the shell 23 of the microcapsule 2 is colored red, the dispersion medium 21 is black, and the electrophoretic particles 20 are white, the microcapsule 2 is observed from the side indicated by reference numeral 10 in FIG. Since light is reflected by the white electrophoretic particles 20, the red color of the shell portion 23 in front of the electrophoretic particles 20 is visually recognized. Further, when the microcapsule 2 is observed from the side indicated by reference numeral 10 in FIG. 5B, light reflection by the electrophoretic particles 20 does not occur, and the black color of the dispersion medium 21 is visually recognized.
[0033]
Next, the case where the electrophoretic particles placed in the microcapsule are of two types (that is, white electrophoretic particles charged to positive polarity and black electrophoretic particles charged to negative polarity) will be described.
[0034]
When an electric field is applied in the direction indicated by symbol E in FIG. 6A, the white electrophoretic particles 20W move to the upper side of the microcapsule 2 and the black electrophoretic particles 20B move to the lower side of the microcapsule 2. Further, when an electric field is applied in the direction indicated by symbol E in FIG. 5B, the white electrophoretic particles 20W move to the lower side of the microcapsule 2 and the black electrophoretic particles 20B move to the upper side of the microcapsule 2. Now, when the shell portion 23 of the microcapsule 2 is colored cyan and the dispersion medium 21 is transparent, the microcapsule 2 is observed from the side indicated by reference numeral 10 in FIG. Is reflected, and cyan in the shell 23 in front of the electrophoretic particles 20W is visually recognized. Further, when the microcapsule 2 is observed from the side indicated by reference numeral 10 in FIG. 6B, the black color of the electrophoretic particles 20B is visually recognized.
[0035]
[Pixel]
The arrangement and shape of the pixels are not particularly limited, but are preferably 3 to 12 polygons (including regular polygons), circles, and the like as viewed from the display surface. Further, when the number of pixels is increased, the arrangement of each color is not particularly limited.
[0036]
[substrate]
As materials for forming the substrates 1a and 1b, ceramics such as glass, alumina and quartz, metals such as aluminum, titanium and stainless steel, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), Examples thereof include plastics such as polyimide (PI), polyetherimide (PEI), and polycarbonate (PC). Note that in the case where it is difficult to ensure mechanical strength, solvent resistance, and the like with a single material, a laminated structure using two or more kinds of materials is preferable. For example, a “reinforced plastic substrate” in which a metal or ceramic filler is added to plastic and molded into a sheet shape may be used. Also,
・ A substrate with improved liquid permeability by covering the surface of a porous ceramic lightweight substrate with a plastic material,
・ A substrate with improved solvent resistance by coating a ceramic material on the surface of a plastic film with poor solvent resistance.
Etc. may be used. By the way, the substrate disposed on the image observer side needs to be transparent.
[0037]
[electrode]
There may be at least a pair of electrodes, and the shape and arrangement thereof are not particularly limited. The first electrode 3a described above may be disposed on the first substrate 1a, and the second electrode 3b may be disposed on the second substrate 1b. There are no particular restrictions on the material of this electrode, but metals such as aluminum and titanium and pastes thereof, conductive metal oxides such as ITO, and conductive polymers such as polyacetylene and polyaniline may be used. These are patterned to control each pixel. The pattern forming method may be a known one, and examples thereof include a printing method and a photolithography method. Further, a switch element may be connected to each first electrode 3a.
[0038]
Next, a method for manufacturing an electrophoretic display device according to the present invention will be described.
[0039]
A method of manufacturing an electrophoretic display device according to the present invention includes:
(1) a step of arranging the microcapsules 2 on the first substrate 1a (hereinafter referred to as “microcapsule arrangement step”);
(2) a step of coloring the region where the microcapsules 2 are arranged (hereinafter referred to as “coloring step”);
(3) A step of attaching the second substrate 1b to the first substrate 1a and sealing the microcapsule 2 (hereinafter referred to as “sealing step”);
It has.
[0040]
[Production of microcapsules]
By the way, as a method for producing the microcapsule, mainly after adding a dispersion medium, electrophoretic particles, a coating material forming a capsule wall, a surfactant, etc., an interfacial polymerization method, an in situ polymerization method, a phase separation method. (Coacervation method).
[0041]
[Microcapsule placement process]
Examples of the method for arranging the microcapsules 2 include a doctor blade method, a knife blade method, a bar coating method, a spin coating method, a printing method such as screen printing and offset printing, an ink jet method, and a method using a dispenser.
[0042]
Further, when the microcapsule is arranged at a desired position on the substrate, the uneven shape may be formed in advance at an arbitrary position on the substrate, and the microcapsule may be arranged therein. The uneven shape is not particularly limited.
[0043]
The arrangement of the microcapsules 2 on the first substrate 1a may be performed by applying a liquid medium in which the microcapsules are dispersed to the first substrate 1a and drying the liquid. The liquid medium is not particularly limited as long as it contains at least a liquid in which the capsule can be dispersed. Accordingly, in addition to organic solvents such as water, alcohol, and acetone, a light-transmitting binder resin (gap member) as described above may be used. When the liquid medium is water or an organic solvent, the microcapsules need to be spread on a substrate and then dried to volatilize.
[0044]
Examples of the light-transmitting binder resin include water-soluble polymers, such as polyvinyl alcohol, polyurethane, polyester, acrylic resin, and silicone resin. Moreover, you may add the pigment | dye which colors the wall of a capsule at this time as needed. This is effective, for example, when displaying in two colors such as red-white display, or when performing the microcapsule placement step and the coloring step simultaneously. The pigment used at this time may be either a pigment or a dye. However, it is essential that the pigment is dispersed in the liquid medium and the binder resin, and that the dye is at least dispersed, preferably dissolved. Specific dye materials include azo, stilbene, thiazole, dioxazine, phthalocyanine direct dyes, azo, anthraquinone, triphenylmethane, xanthene acid dyes, basic dyes, monoazo, disazo. , Anthraquinone, phthalocyanine and triallylmethane oil-soluble dyes, reactive dyes, and the like. Specific pigment materials include titanium oxide, aluminum oxide, zinc oxide, lead oxide, tin oxide, magnesium sulfate, silica, carbon black, aniline black, manganese ferrite black, cobalt ferrite black, titanium yellow, yellow iron oxide, yellow Inorganic pigments such as lead can be used. Also, as each primary color pigment, red pigments such as cadmium red, quinacridone red, lake red, brilliant carmine, madder lake, green pigments such as diamond green lake, phthalocyanine green, pigment green, cobalt blue, Victoria blue lake, phthalocyanine blue, Blue pigments such as Fast Sky Blue, yellow pigments such as Hansa Yellow, Benzidine Yellow, Cadmium Yellow, Fast Yellow, Disazo Yellow, Hansa Yellow, Disazo Yellow and the like can be used.
[0045]
[Coloring process]
The coloring of the region where the microcapsules 2 are arranged is as follows:
Even if it is achieved by coloring the microcapsule itself (that is, the shell itself indicated by reference numeral 23 in FIG. 5) as shown in FIG. 1 and FIG.
-Even if it is achieved by coloring the outer surface of the microcapsule 2 (that is, the outer surface of the shell),
・ Even if it is achieved by making the microcapsule transparent and coloring its inner surface,
As shown in FIG. 3, even if it is achieved by coloring the gap members 4R, 4G, 4B arranged in the gaps of the microcapsules 2,
・ Even if it achieves combining those methods,
good.
[0046]
Further, in the electrophoretic display device shown in FIGS. 1 to 3, the color given to the region where the microcapsules 2 are arranged is different for each pixel. In such a case,
・ Even if the three pixels are painted red (R), green (G) and blue (B) separately,
-Even if the four pixels are painted separately in yellow (Y), magenta (M), cyan (C) and black (K),
・ Even if you paint it in other colors,
good. Furthermore, the region where the microcapsules 2 are arranged may be colored only by one color (that is, all pixels are colored by one color).
[0047]
The region where the microcapsules 2 are arranged may be colored by a printing method, an ink jet method, or a dispenser method.
[0048]
The coloring of the microcapsules is achieved by applying a dye to any area of the microcapsules. The pigment used at this time may be either a pigment or a dye.
[0049]
Specific dye materials include azo, stilbene, thiazole, dioxazine, phthalocyanine direct dyes, azo, anthraquinone, triphenylmethane, xanthene acid dyes, basic dyes, monoazo, disazo. , Anthraquinone, phthalocyanine and triallylmethane oil-soluble dyes, reactive dyes, and the like. Specific pigment materials include titanium oxide, aluminum oxide, zinc oxide, lead oxide, tin oxide, magnesium sulfate, silica, carbon black, aniline black, manganese ferrite black, cobalt ferrite black, titanium yellow, yellow iron oxide, yellow Inorganic pigments such as lead can be used. Also, as each primary color pigment, red pigments such as cadmium red, quinacridone red, lake red, brilliant carmine, madder lake, green pigments such as diamond green lake, phthalocyanine green, pigment green, cobalt blue, Victoria blue lake, phthalocyanine blue, Blue pigments such as Fast Sky Blue, yellow pigments such as Hansa Yellow, Benzidine Yellow, Cadmium Yellow, Fast Yellow, Disazo Yellow, Hansa Yellow, Disazo Yellow and the like can be used.
[0050]
As a method for coloring the microcapsules (that is, a method for applying a dye to an arbitrary region), a printing method (offset printing, screen printing, or the like), an inkjet method, or a dispenser method may be used. When applying a plurality of pigments, it is necessary to prevent color mixing.
[0051]
In addition, you may make it perform a microcapsule arrangement | positioning process and a coloring process simultaneously. For example, a liquid medium in which a pigment that emits a desired color and microcapsules are dispersed is prepared in advance for the required color type, and an arbitrary region is printed on the substrate by a printing method such as an inkjet method, offset printing, or screen printing. It is the method of apply | coating to. Regardless of the type of color required, the same microcapsules are used, so that the manufacturing process remains simple. As the material used in this case, the materials described above may be used.
[0052]
[Sealing process]
This is a process of covering and sealing the microcapsule layer disposed on the first substrate with the first substrate. In this case, the two substrates may be sealed under pressure so that the gap between the microcapsules is eliminated as much as possible. However, if there is a possibility that the pressed microcapsules may be crushed and occupy a wider area than an arbitrary area by pressing, the colored area is narrowed in advance, and then pressed and sealed. It is necessary to devise such that the arbitrary region and the colored region of the microcapsule are matched.
[0053]
Next, the effect of this embodiment will be described.
[0054]
According to the present embodiment, since the coloring step is performed after the microcapsule arranging step, the microcapsule arranging operation is simplified and the working time is shortened.
[0055]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
[0056]
Example 1
In this example, the electrophoretic display device shown in FIG. 1 was produced.
[0057]
First, aluminum was formed to a thickness of about 0.2 μm on a 200 μm-thick PET film (first substrate) 1a, and patterned to form an aluminum electrode (first electrode) 3a.
[0058]
Next, the microcapsule 2 was produced. That is,
-Titanium oxide (DuPont Tiprue R-104) as white electrophoretic particles,
A mixture of titanium black (13M-T, manufactured by Mitsubishi Chemical Corporation) at a weight ratio of 1: 1 as black electrophoretic particles was mixed in trichlorethylene as a dispersion medium by 10% by weight. Next, 0.5% by weight of a surfactant (OLONITE Japan Co., Ltd. OLOA1200) was mixed with the dispersion medium.
[0059]
Then, the solution thus prepared was added to a protective colloid aqueous solution and stirred to emulsify. Next, sodium carbonate was added to adjust the pH to 9, urea-formaldehyde prepolymer was added, and acetic acid was further added to adjust the pH to 5, followed by reaction at 60 ° C. for 2 hours. As a result, the prepolymer polymerized at the interface of the dispersion to form a urea resin film. In this way, a microcapsule slurry using urea resin as a wall material was obtained. The emulsification conditions were adjusted so that the particle size was 40 μm, and further, the particle size was classified so as to be 30 to 50 μm in order to adjust the particle size distribution.
[0060]
The microcapsules thus prepared were added to water so as to have a ratio of 10% by weight to prepare a microcapsule dispersion. The microcapsule dispersion was spread on a substrate using a blade coater and dried to prepare a microcapsule layer (microcapsule placement step).
[0061]
On the other hand, 3% by weight of Acid Red 14 (manufactured by Aldrich), 7.5% by weight of diethylene glycol and propylene glycol, 5% by weight of isopropyl alcohol and 0.5% by weight of surfactant were added, and the red aqueous solution was added. Produced.
[0062]
This was colored in a predetermined color in an arbitrary area using an inkjet apparatus in which the head of an inkjet printer (BJF600 manufactured by Canon Inc.) was attached to the X-axis stage of the XY stage. After that, by drying and removing excess moisture, the dye was dyed and adsorbed on the wall material 23 of the microcapsule (coloring step).
[0063]
Further, an ITO (second electrode) 3b having a thickness of about 0.1 μm was formed on a PET film (second substrate) 1b having a thickness of 200 μm. And these PET films 1a and 1b were bonded together and the microcapsule 2 was sealed.
[0064]
As a result of providing a voltage applying means and applying a voltage, a display element that performs red-black display was obtained. Moreover, color display with good contrast was achieved.
[0065]
(Example 2)
In this example, the electrophoretic display device shown in FIG. 3 was produced.
[0066]
First, an aluminum electrode 3a was formed on the PET film 1a by the same method as in Example 1.
[0067]
Next, the microcapsule 2 was produced. However, as the electrophoretic particles, the black electrophoretic particles are not used, and only the titanium oxide (DuPont Tiprue R-104) is used as the white electrophoretic particles, and the black oil-soluble dye Sudan black is used as the dispersion medium. Trichloroethylene containing 3% by weight of 3 (manufactured by Aldrich) was used. The dispersion medium was mixed with 10% by weight and 0.5% by weight of white electrophoretic particles and a surfactant (OLONA Japan Co., Ltd. OLOA1200).
[0068]
Then, the solution thus prepared was added to a protective colloid aqueous solution and stirred to emulsify. Next, sodium carbonate was added to adjust the pH to 9, urea-formaldehyde prepolymer was added, and acetic acid was further added to adjust the pH to 5, followed by reaction at 60 ° C. for 2 hours. As a result, the prepolymer polymerized at the interface of the dispersion to form a urea resin film. In this way, a microcapsule slurry using urea resin as a wall material was obtained. The emulsification conditions were adjusted so that the particle size was 40 μm, and further, the particle size was classified so as to be 30 to 50 μm in order to adjust the particle size distribution.
[0069]
The microcapsules thus prepared were added to water so as to have a ratio of 10% by weight to prepare a microcapsule dispersion. The microcapsule dispersion was spread on a substrate using a blade coater and dried to prepare a microcapsule layer.
[0070]
On the other hand, a 10% by weight aqueous solution of polyvinyl alcohol was prepared, and AcidRed 14 (manufactured by Aldrich) and Acid Blue 45 (manufactured by Aldrich) were added to each 3% by weight to prepare a red binder resin and a blue binder resin.
[0071]
Next, an opening mask on which an arbitrary pattern was formed was placed on the microcapsule layer, and the red binder resin 4R was printed on the microcapsule layer using a squeegee. Thereafter, drying was performed, and then the same operation was performed on the blue binder resin 4B to print on the microcapsule layer.
[0072]
Further, an ITO (second electrode) 3b having a thickness of about 0.1 μm was formed on a PET film (second substrate) 1b having a thickness of 200 μm. And these PET films 1a and 1b were bonded together, and the microcapsule 2 was sealed.
[0073]
Further, as a result of applying a voltage by providing a voltage applying means, a display element having pixels that perform blue-black display and pixels that perform red-black display according to an arbitrary pattern region of the opening mask was obtained. Further, there was no color mixture between the two types of pixels, and color display with good contrast could be achieved.
[0074]
(Example 3)
In this example, first, an aluminum electrode 3a was formed on the PET film 1a by the same method as in Example 1. Further, microcapsules 2 were produced and classified in the same manner as in Example 2.
[0075]
Next, a 10% by weight aqueous solution of polyvinyl alcohol is prepared, and Acid Red 14 (manufactured by Aldrich) and Acid Blue 45 (manufactured by Aldrich) are mixed by 3% by weight, and 10% by weight of microcapsules 2 are added. Then, a red adjustment liquid and a blue adjustment liquid were prepared.
[0076]
Next, using a dispenser device (SM3 SL-3A manufactured by Musashi Engineering Co., Ltd.), the red adjustment liquid was applied to the PET substrate while patterning. Thereafter, drying was performed, and then the same operation was performed with respect to the blue adjustment liquid to produce a microcapsule layer.
[0077]
Thereafter, as in Examples 1 and 2, the microcapsule 2 was sealed by bonding the substrates using a PET film 1b and ITO 3b.
[0078]
Further, a voltage applying means was provided to form a display element, and display was performed. As a result of driving the electrophoretic particles in the microcapsule forming each pixel between the upper and lower electrodes, a display element having pixels that perform blue-black display and pixels that perform red-black display was obtained. Further, there was no color mixture between the two types of pixels, and color display with good contrast could be achieved.
[0079]
【The invention's effect】
As described above, according to the present invention, since the coloring process is performed after the microcapsule arranging process, the microcapsule arranging work is simplified and the working time is shortened.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an example of a structure of an electrophoretic display device according to the invention.
FIG. 2 is a cross-sectional view illustrating an example of the structure of an electrophoretic display device according to the invention.
FIG. 3 is a cross-sectional view showing an example of the structure of an electrophoretic display device according to the invention.
FIG. 4 is a schematic diagram showing an example of image display.
FIG. 5 is a schematic diagram for explaining another example of image display.
FIG. 6 is a schematic diagram for explaining another example of image display.
[Explanation of symbols]
1a First substrate
1b Second substrate
2 Microcapsules
3a First electrode
3b Second electrode
4 Gap member
20 Electrophoretic particles
21 Dispersion medium

Claims (4)

A first substrate and a second substrate arranged with a predetermined gap therebetween, a plurality of microcapsules having electrophoretic particles and a dispersion medium and arranged in the gap between the substrates, and sandwiching these microcapsules In a method of manufacturing an electrophoretic display device comprising a first electrode and a second electrode arranged,
Producing a plurality of microcapsules in which white electrophoretic particles charged to positive polarity and black electrophoretic particles charged to negative polarity are dispersed in the transparent dispersion medium;
Disposing the plurality of microcapsules on the first substrate;
Coloring the region in which the microcapsules are disposed;
Bonding the second substrate to the first substrate and sealing the microcapsule;
A method for manufacturing an electrophoretic display device, comprising:   The method for manufacturing an electrophoretic display device according to claim 1, wherein the coloring step is a step of coloring a shell of a microcapsule.   The method for manufacturing an electrophoretic display device according to claim 1, wherein the coloring step is a step of coloring the outer surface of the shell of the microcapsule.   The method of manufacturing an electrophoretic display device according to claim 1, wherein the coloring step is a step of coloring a gap member disposed in a gap between microcapsules.

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