KR100977182B1 - Electronic paper display apparatus and manufacturing process thereof and its structure - Google Patents

Abstract

PURPOSE: An electronic paper display device capable of obtaining a charged particle which particle distribution diagram is small and a manufacturing method thereof, and a structure thereof are provided to use electrolyte, thereby improving a particle adsorption force. CONSTITUTION: An upper substrate(110) and a lower substrate(120) is arranged to face each other in predetermined interval. An upper electrode(130) and a lower electrode(140) is formed to inscribe with the lower substrate and the upper substrate. A partition wall divides pixels in between the upper electrode and the lower electrode. The partition wall forms a cell. An charged particles(160,170) is filled between the partition walls.

Description

Electronic paper display device, manufacturing method and structure thereof {ELECTRONIC PAPER DISPLAY APPARATUS AND MANUFACTURING PROCESS THEREOF AND ITS STRUCTURE}

The present invention relates to an electronic paper display device, a method for manufacturing the same, and a structure thereof, and more particularly, to produce particles by an emulsion-free polymerization method and a dispersion polymerization method by appropriately using a reaction such as a synthesis initiator and a silica nanocomposite. The present invention relates to an electronic paper display device, a method of manufacturing the same, and a structure thereof, which control agglomeration of charged particles, use charged particles excellent in durability and flowability, and easily form partition walls by using an imprint method. will be.

BACKGROUND ART Conventionally, as an image display device replacing a liquid crystal display device (LCD), electronic paper using techniques such as an electrophoretic method, an electrochromic method, a thermal method, and a two-color particle rotation method has been proposed. These prior arts are considered to be a technology that can be used in an inexpensive image display device because of the advantages of having a wider viewing angle closer to a normal printed matter, a smaller power consumption, and a memory function than LCDs. , Electronic paper and the like are expected.

The dual electronic paper technology uses the rapid movement of microparticles by an electric field to electrostatically move charged particles floating in a certain space to display colors. Therefore, even if the voltage is removed, the image does not disappear because there is no change in the position of the particles, so that the effect as if printed on paper is printed. In other words, it does not emit light by itself, but the visual fatigue is very low, so it is possible to enjoy a comfortable viewing like a real book, and the panel's flexibility is high enough to bend and the thickness can be formed very thin. There is great expectation as a display device technology. In addition, as mentioned, power consumption is extremely low since the displayed image is maintained for a long time unless the panel is reset, thereby making it excellent as a portable display device. In particular, low prices due to simple processes and low cost materials are expected to contribute to the popularization of electronic paper.

Electronic paper techniques generally used include electrophoretic methods for microencapsulating a dispersion consisting of dispersed particles and a colored solution, and disposing the dispersion liquid between opposing substrates to cause particles to move in the liquid; Without using a solution, two or more kinds of particles having different colors and charging characteristics are enclosed between at least one transparent substrate, and an electric field is applied to the particles from an electrode pair consisting of electrodes formed on one or both of the substrates. A collision charging method has been proposed in which an charged particle having a different polarity is moved and moved in different directions by a Coulomb force to display an image.

1 is a cross-sectional view showing a cell structure for such a collision charged electronic paper. As shown, the collision charged electronic paper includes an upper substrate 10 and a lower substrate 20 formed of either plastic or glass. And applying a driving voltage of the device on the substrate, and maintaining a constant gap between the upper electrode 30 and the lower electrode 40 formed of the transparent electrode, and the upper substrate 10 and the lower substrate 20. And a partition wall 50 separating the cell from the cell, and the positive charged particles 60 and the negative charged particles 70 existing between the upper electrode 30 and the lower electrode 40.

In the collision charged electronic paper having the above structure, when sufficient voltage is applied to the upper electrode 30 and the lower electrode 40, charged particles 60 and 70 charged according to the applied electrode polarity are transferred to each electrode. Attracted. For example, when − voltage is applied to the lower electrode 40 and + voltage is applied to the upper electrode 30, the black charged particles 60 positively charged by the coulomb force move toward the lower substrate 20. In addition, the negatively charged white charged particles 70 move toward the upper substrate 10. As a result, since the white charged particles 70 are located on the upper substrate 10 side, the white charged particles 70 appear white when viewed from the outside. On the contrary, when + voltage is applied to the lower electrode 40 and − voltage is applied to the upper electrode 30, the black charged particles 60 move toward the upper substrate 10, and thus appear black.

Regardless of which type of electrophoresis method or collision charging method is used, a technique for forming fluidized charged particles (hereinafter referred to as 'charged particles') should be accompanied, and these charged particles are generally illustrated in FIG. 2. As described above, the structure of the inorganic external additive 4 such as silicon particles and the coupling agent is coated on the surface of the polymer particles 11 including the charge control agent 12 and the dye / dye 13.

As the charged particles, an external blending method is performed by adding an external additive 14 to a dispersion solvent including the polymer particles 11, the charge control agent 12, and the dye / dye 13. have. In the charged particles according to this method, the polymer particles 11 and the external additives 14 are physically bonded, and there is a problem in that the externally attached components easily fall off due to the limitation of the durability of the physical bonding. Thus, when the external additive 14 easily falls, the charged particles cannot sufficiently respond to the same applied voltage, and the charging characteristics also change easily, resulting in a problem of deterioration in image quality. In addition, the longer the use time due to the departure of the external additive, there is a problem that the probability of occurrence of aggregation between the particles increases.

In addition, in the case of the polymer particles used in the charged particles, a polymerization method according to emulsion polymerization, dispersion polymerization or suspension polymerization is used. Since the polymer particles thus prepared mostly exhibit lipophilic surface properties, hydrophilic functional groups are formed on the surface of the polymer particles. It is difficult to apply a new polymerization method for the introduction of the hydrophilic functional group in order to obtain the polymer particles bound, and unlike most commercial lipophilic polymer particles, very high in order to obtain the polymer particles into which the hydrophilic functional groups are introduced. In addition to the cost, there is a problem in that a cumbersome and inexpensive manufacturing method such as using a surfactant is used.

In addition, the conventional method of forming the partition wall is based on the photolithography method using the photoresist (PR), as shown in Figures 4a to 4d. That is, as shown in FIG. 4A, the photoresist 300 is coated with a material for forming a partition on the substrate 100 on which the electrode 200 is formed, and as shown in FIG. 4B, a region in which the partition is to be formed is divided. In order to form a pattern 400 to block the light on the photoresist 300 with a pre-made photomask or the like. Thereafter, as shown in FIG. 4C, when the light is exposed using light, only the region distinguished by the pattern 400 is etched to form the barrier rib 500 as illustrated in FIG. 4D. Since the method of forming the barrier rib 500 using the photolithography method requires an exposure process using a separate light, the manufacturing method is complicated, and a separate exposure apparatus is required for the exposure process. There is a problem that the manufacturing process is cumbersome.

In addition, since the bulkhead has been mainly etched by a photo process, photoresist (PR) has been most widely used as a bulkhead material, and polyethylene terephthalate (PET) and polyether sulfone ( Polymers such as PES), polyethylene (PE), polycarbonate (PC), polypropylene (PP) or inorganic materials.

However, conventional inorganic or polymer materials, including photoresist, have lacked adhesion to a substrate or an electrode. Even when the adhesive is applied to the partition wall, when the adhesive force with the substrate or the electrode is deteriorated and the shape of the display device is deformed and bent, the partition wall is frequently lifted. This has a problem of lowering the overall quality of the display device. For this reason, in the method of manufacturing an electronic paper display device, there is a need for a barrier formation method in which barrier ribs can be formed more easily and simply, and the adhesion between the substrate and the electrode does not easily drop.

In addition, the partition wall generally has a rectangular shape, and the charged particles are stagnant at each corner portion, or a lot of charged particles are required to fill between the partition walls. This causes a problem that the response time of the electronic paper display device is delayed.

The present invention is to solve the above problems, an object of the present invention is to improve the particle attracting force by using an electrolyte, and to apply a co-solvent such as water and ethanol to prepare a charged particle with good uniformity, to the collision charging method It is an object of the present invention to provide a suitable method for polymerizing polymer particles having a small particle distribution.

In addition, another object of the present invention is to form a partition wall by using a separate mold, and to form the partition wall quickly and in large quantities without the complicated and difficult photo process work as in the prior art, and the partition wall is formed by the photocurable composition. It is an object of the present invention to provide an electronic paper display device having high elasticity and having high bonding strength with the substrate and the electrode.

In addition, by forming a U-shaped or V-shaped uneven partition wall, it is aimed at preventing the stagnant phenomenon of the charged particles at the corner portion and reducing the amount of charged particles between the partition walls, thereby shortening the reaction time of the electronic paper display device. .

Electronic paper display device of the present invention for achieving the above object,

The upper substrate and the lower substrate disposed to face each other at a predetermined interval; An upper electrode and a lower electrode formed to be inscribed on the lower substrate and the upper substrate, respectively; Barrier ribs forming a cell by dividing pixels between the upper electrode and the lower electrode; Charged particles filled between the partition walls; comprising, wherein the charged particles are based on 100 parts by weight of a solvent containing any one of methanol or ethanol and water, 5 to 20 parts by weight of monomer, 0.01 to 0.5 by weight of a synthetic initiator Part, characterized in that it comprises 0.01 to 2 parts by weight of the electrolyte.

In addition, the solvent consists of water and ethanol, the monomer is styrene or methyl methacrylate, the electrolyte is sodium chloride (NaCl), sodium bicarbonate (NaHCO ₃ ), sodium pyrosulfate (Na ₂ S ₂ O ₇ ) or carbonic acid Any one of potassium (K ₂ CO ₃ ), the synthesis initiator is any one of potassium persulfate (KPS) or 2,2'-azobis (isobutyronitrile), the charged particles, It further comprises at least one of silicon nanoparticles, charge control agent, particle stabilizer and colorant,

The partition wall is formed in a U-shaped or V-shaped uneven shape, the interval between the unevenness is characterized in that 0㎛ to 50㎛.

The manufacturing method of the electronic paper display device of the present invention for achieving the above object,

An electrode forming step of forming a lower electrode on the lower substrate and forming an upper electrode on the upper substrate; An application step of preparing a mold having a concave-convex structure and applying a photocurable composition on the concave-convex structure; Positioning the lower substrate so that the injected photocurable composition and the lower electrode face each other, and then curing the photocurable composition by irradiating UV with the photocurable composition; A partition wall forming step of forming a partition wall by separating the lower electrode and the cured photocurable composition from a mold; A filling step of filling charged cells in a cell formed by the partition wall; And laminating the upper substrate on the upper surface of the partition wall so that the upper electrode faces the lower electrode, and bonding the upper substrate to the lower substrate, wherein the charged particles of the filling step are either methanol or ethanol. With respect to 100 parts by weight of a solvent containing water, 5 to 20 parts by weight of monomer, 0.01 to 0.5 parts by weight of synthetic initiator, 0.01 to 5 parts by weight of electrolyte, 0.01 to 5 parts by weight of particle stabilizer, and the filling step, A polymer polymerization step of mixing and dispersing the charged particles and dispersing the dispersed solution at a temperature of 40 to 90 ° C. for 15 to 26 hours to produce polymer particles; A reaction step of reacting the polymer particles with a solution containing silica nanoparticles and a colorant; It characterized in that it comprises a; drying step of drying the solution.

In addition, the uneven structure of the mold in the application step is made of a U-shaped or V-shaped, characterized in that the interval between the unevenness is 0㎛ to 50㎛.

In addition, the photocurable composition is an ester-type or ether-type polymer in which acrylyl or allyl system is coupled to the sock end of polyethylene glycol (PEG) or polypropylene glycol (PPG), and the polymer polymerization step includes inert gas in the charged particles. Supplying, the oxygen removal step of removing the dissolved oxygen contained in the solvent; characterized in that it further comprises.

The structure of the electronic paper display device of the present invention for achieving the above object,

A lower electrode formed to be in contact with the lower substrate and the lower substrate; Barrier ribs formed in the form of U-shaped or V-shaped unevenness, and having an interval between unevennesses of 0 µm to 50 µm; A cell formed by the partition wall; Charged particles filled in the cell; And an upper electrode formed on the upper substrate and in contact with the upper substrate.

According to the electronic paper display device of the present invention, and a method for manufacturing the same, and a structure thereof, the particle attracting force is improved by using an electrolyte, and co-solvents such as water and ethanol are applied to prepare charged particles having good uniformity. Suitable charged particles having a small particle distribution can be obtained.

In addition, by forming the partition wall using a separate mold, it is possible to form the partition wall quickly and in large quantities without the complicated and difficult photo-processing work as in the prior art, by forming the partition wall by the photocurable composition, has a high elasticity, An electronic paper display device having a high bonding strength with a substrate and an electrode can be manufactured.

In addition, by forming a U-shaped or V-shaped partition wall, there is an effect of preventing the stagnant phenomenon of the charged particles and the amount of charged particles between the partition walls, thereby reducing the reaction time of the electronic paper display device.

Hereinafter, an electronic paper display device according to the present invention, a method for manufacturing the same, and a structure thereof will be described in detail with reference to the accompanying drawings. The invention can be better understood by the following examples, which are intended for the purpose of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

First, Figure 3 is a cross-sectional view showing a cell structure of the electronic paper display device according to an embodiment of the present invention, as shown here, the electronic paper display device of the present invention, the upper portion disposed facing a predetermined interval An upper electrode 130 and a lower electrode 140 formed on the substrate 110 and the lower substrate 120, the lower substrate 120 and the upper substrate 110, respectively, and the upper electrode 130 and the upper substrate 110. And a partition wall 150 for dividing pixels between the lower electrodes 140 to form cells, and charged particles 160 and 170 filled between the partition walls.

Here, looking at the partition wall 150, Figure 8 is a cross-sectional view of the electronic paper display device according to an embodiment of the present invention, as shown here, the partition wall 7 is U-shaped cross-section, The space | interval d between unevenness | corrugation is 10 micrometers. As shown in FIG. 1, the partition wall 50 of the conventional electronic paper display device generally has a rectangular shape, and the charged particles are stagnant at each corner portion or the space between the partition walls is wide, so that the charged particles may be filled. I needed a lot. Due to this, there is a problem that the reaction time is delayed. In the present invention, the cross section of the partition wall has a U-shaped or V-shaped uneven shape, which prevents stagnation of charged particles and decreases the space between the partition walls. The screen can also be displayed by the charged particles. Accordingly, the response time of the electronic paper display device is also substantially shortened. In addition, by reducing the interval between the unevenness to 0 μm to 50 μm than the conventional unevenness of the conventional unevenness, it is possible to maximize the effect of the U-shaped or V-shaped unevenness.

Next, looking at the charged particles (160, 170) filled between the partition wall 150,

First, a solvent is a mixture of water or alcohol, that is, co-solvent. The monomer is not particularly limited as long as it can be non-emulsified, but is preferably styrene, methyl methacrylate, ethylene terephthalate, styrenesulfonate, vinyl acetate, methyl styrene, acrylic acid, butyl methacrylate, ethyl methacrylate. It can be used by the method of individual or copolymerizing monomers, such as a rate, 2-ethylhexyl acrylate, and N-vinyl caprolactam. In a preferred embodiment of the present invention, styrene and methyl methacrylate are used as monomers.

Second, in the case of using styrene as the monomer, it is preferable to use water and ethanol as the solvent, and to adjust the weight ratio of water and ethanol forming the cosolvent to 100: 40 to 100: 1. Preferably, it is more preferably 100: 25 to 100: 5. As a result of the experiment, there was a problem in that the particle size distribution was widened when the composition having a weight ratio of water: ethanol was used in a range other than that.

When methyl methacrylate is used as the monomer, it is preferable to use water and methanol as a solvent, and it is preferable to adjust the weight ratio of water and methanol forming the co-solvent to 20: 100 to 80: 100. More preferably, it is 30: 100-50: 100. As a result of the experiment, when using a composition having a weight ratio of water: methanol other than that, there was a problem in that the particle size distribution was widened.

The content of the monomer is preferably 5 to 20 parts by weight, more preferably 8 to 15 parts by weight with respect to 100 parts by weight of the solvent. When the monomer is added in less than 5 parts by weight, there is a problem that the resulting polymer particles are less likely to be charged, when exceeding 20 parts by weight, the silica nanoparticles as external additives do not sufficiently wrap the surface of the polymer particles and durability And fluidity is lowered.

Third, the charged particles form a form in which the silica nanoparticles are chemically bonded to the surface of the polymer particles produced by the polymerization of the monomer due to the action of the synthesis initiator and the silica nanoparticles. All free radical polymerization initiators which can trigger non-emulsification polymerization which are generally used are included. Synthetic initiators may in principle comprise both peroxides and azo compounds. The peroxide may in principle be a mono- or di-alkali metal salt or an ammonium salt of an inorganic peroxide such as hydrogen peroxide or peroxodisulfate such as peroxodisulfate, for example mono- and di-sodium and -Potassium salts, or ammonium salts, or can be organic peroxides such as alkyl hydroperoxides, for example tert-butyl, p-mentyl and cumyl hydroperoxides, and also dialkyl or diaryl peroxides Such as di-tert-butyl peroxide or dicumyl peroxide. The compounds used are mainly 2,2'-azobis (isobutyronitrile) (AIBN), 2,2'-azobis (2,4-dimethylvaleronitrile) and 2,2'-azobis (ami) Dinopropyl) dihydrochloride (AIBA)).

Fourth, suitable oxidants for the redox initiator system are essentially the peroxides mentioned above. Correspondingly, the reducing agents used are compounds of low sulfur state, such as alkali metal sulfites such as potassium and / or sodium sulfite, alkali metal hydrogen sulfites such as potassium and / or sodium hydrogen sulfite, Alkali metal metabisulfite, for example potassium and / or sodium metabisulfite, formaldehyde-sulfoxylate, for example potassium and / or sodium formaldehyde-sulfoxylate, alkali metal salts, in particular potassium of aliphatic sulfinic acid Salts and / or sodium salts, and alkali metal hydrogen sulfides such as potassium and / or sodium hydrogen sulfide, salts of polyvalent metals such as iron (II) sulfate, iron (II) ammonium sulfate, iron (II) ) Sulfates, endiols such as dihydroxymaleic acid, benzoin and / or ascorbic acid, and reduced saccharides such as sorbose, glucose, fructose and / or Dihydroxyacetone.

Fifth, as the synthetic initiator preferably used in the charged particles, in the case of performing the non-emulsification polymerization method according to the first embodiment, potassium persulfate (KPS) is used, and the dispersion polymerization according to the second embodiment 2,2'-azobis (isobutyronitrile) (AIBN) is used when the process is carried out.

In particular, in the preparation of charged particles using an electrolyte, it serves to remarkably strengthen nuclear agglomeration and to facilitate particle adsorption. Specifically, the electrolyte is not particularly limited as long as it can act as an electrolyte, but is not limited to sodium chloride (NaCl), sodium bicarbonate (NaHCO ₃ ), sodium pyrosulfate (Na ₂ S ₂ O ₇ ) or calcium carbonate (K ₂ CO ₃ ). It is preferable to use either.

Sixth, in addition to the above structure, any one of a charge control agent such as a silicon nanoparticle, a positive (+) charge control agent or a negative (-) charge control agent, a particle stabilizer, an organic colorant, or an inorganic colorant One or more of a colorant, alone or in a mixed form, the polymerized polymer batch to produce charged particles coated with an external additive in a batch in the polymerization step, without going through a separate reaction step (in-situ polymerization). The silica nanoparticles used in this case are not particularly limited as long as they can form a stabilizing layer as an external additive of charged particles, but preferably LUDOX AM30®, SS-SOL 30F®, Aerosil®, and the like.

As charge control agents, positively charged charge control agents such as nigrosine dyes, triphenylmethane compounds, quaternary ammonium salt compounds, polyamine resins or imidazole derivatives, metal salicylic acid complexes, and metals containing metal ions or metal atoms Negative charge charge control agents such as azo dyes, metal-soluble dyes, quaternary ammonium salt-based compounds, calix arene compounds, boron-containing compounds (boron benzyl chloride complexes) or nitroimidazole derivatives; And other charge control agents usable for the charged particles for electronic paper.

Particle stabilizers are mainly used for dispersion polymerization. In the case of dispersion polymerization, the force causing dispersion is due to stirring in the agitator, but when relying only on stirring, there is a problem in that the colloidal stability is lowered and the particle size distribution is increased. use. As the particle stabilizer preferably used in the present invention, any one of polyvinylpyrrolidone (PVP), an acrylic resin, or an acrylic latex may be used alone or in combination of two or more thereof.

The colorant may be an organic colorant such as nigrosine, methylene blue, quinoline yellow, or rose bengal, titanium oxide, zinc oxide, zinc sulfide, antimony oxide, calcium carbonate, lead white, talc, silica or calcium silicate. , Alumina White, Cadmium Yellow, Cadmium Red, Cadmium Orange, Titanium Yellow, Royal Blue, Ultramarine Blue, Cobalt Blue, Cobalt Green, Cobalt Violet, Iron Oxide, Carbon Black, Manganese Ferrite Black, Cobalt Ferrite Black, Copper Powder or Aluminum The same inorganic colorant may be included, in addition, various colorants may be included without limitation. Generally, titanium oxide (TiO ₂ ) is used to coat white particles, and carbon black is used to coat black particles.

Next, a method of manufacturing the electronic paper display device for manufacturing the electronic paper display device according to the present invention configured as described above will be described with reference to FIGS.

As shown in FIG. 5, in the method of manufacturing the electronic paper display device according to the present invention, an electrode for forming the lower electrode 140 on the lower substrate 120 and the upper electrode 130 on the upper substrate 110 is provided. Forming step (S10), preparing a mold (1) having a concave-convex structure on the surface, the coating step (S20) for applying a photocurable composition (2) on the concave-convex structure, the injected photocurable composition (2) and the After placing the lower substrate 3 to face the lower electrode 140, the curing step (S30) to irradiate and cure the photocurable composition (2), the lower electrode and the cured photocurable composition (2 ) Separating the mold from the mold 1 to form a partition wall (S40), a filling step (S50) for filling the charged particles 9 in the cell formed by the partition wall (S50), the upper substrate 8 to the upper The lower layer is stacked on the upper surface of the partition wall so that the electrode faces the lower electrode. It comprises a bonding step (S60) for bonding with the plate (4).

In addition, the charged particles in the filling step (S50) is already configured as described above, the charged particles are mixed and dispersed, the dispersed solution is polymerized by dispersing and polymerizing the dispersed solution at a temperature of 40 to 90 ℃ for 15 to 26 hours The resulting polymer polymerization step (S53), the polymer particles, the reaction step of reacting the solution containing the silica nanoparticles and the colorant (S54) is prepared through the drying step (S55) to dry the solution.

Here, in the electrode forming step S10, as shown in FIG. 3, the lower electrode 140 is formed on the lower substrate 120, the upper electrode 130 is formed on the upper substrate 110, and the upper electrode ( At least one of the 130 and the lower electrode 140 may be a transparent indium-tin oxide electrode.

The lower and upper insulating layers may be selectively formed on the upper electrode 130 and the lower electrode 140, respectively. Although it is omitted, there is no problem in driving, but if the electrons are generated as the charged particles are in close contact with the electrode, the memory effect is reduced, so it is preferable to apply the image since it may be difficult to preserve the image for a long time without applying a new power source.

Application step (S20), first, the surface as shown in Figure 6a undergoes a step of preparing a mold having a concave-convex structure. As shown in FIG. 6A, the mold 1 has a concave-convex structure formed on a substrate, thereby providing a seat or a space where a partition wall is formed. In other words, the barrier rib is not directly formed on the substrate, but indirectly, and the barrier rib is attached to the substrate by a separate indirect mold (mould).

In the mold 1, it is preferable that the uneven structure is formed on the surface by a dry etching, a wet etching, or a sanding process.

In the present invention, the concave-convex structure is to provide a space for forming the partition wall, it is preferable to form the concave-convex structure at intervals corresponding to the distance between the partitions to be made, preferably the cross-section of the partition is U-shaped or V-shaped uneven It is made of a shape, the interval (d) between the unevenness is 0㎛ to 50㎛ is suitable to increase the display resolution of the charged particles, the U-shaped or V-shaped shape is to prevent the charged particles from stagnating at the corner portion It has the advantage of maximizing fluidity.

Next, as shown in FIG. 6B, the photocurable composition 2 is applied to the mold 1 having the uneven structure. The photocurable composition (2) used by this invention refers to the composition hardened | cured by light, and is distinguished from the thermosetting composition or water-curable composition hardened | cured by heat or moisture. The thermosetting composition or the water-curable composition is hardened by heat or moisture, which requires a long curing time, and is not suitable for a roll-to-roll process to be applied to electronic paper. It is selected as the partition material according to the present invention. Such a photocurable composition (2) is not particularly limited and may include any known one to those skilled in the art, and among these, the photocurable composition (2) includes a UV curing agent for curing light It is desirable to. For example, the photocurable composition (2) is preferably an ester or ether type polymer in which acrylyl or allyl system is bonded to the end of polyethylene glycol (PEG) or polypropylene glycol (PPG), or polyethylene glycol (PEG). Urethane-type photocurable compositions formed by reacting a) with aminated polyoxyethyllene bisamine and acroryl are also possible. The method of applying such a photocurable composition 2 to the mold 1 according to the present invention is also not particularly limited.

In the curing step (S30) as shown in Figure 6c by placing the lower substrate 3 so that the coated photocurable composition (2) and the lower electrode facing, and irradiating the photocurable composition (2) with ultraviolet light The chemical composition 2 is cured and attached to the lower substrate 3. Here, irradiating ultraviolet rays is for curing the photocurable composition 2 according to the present invention and attaching it to the lower substrate 3. When the photocurable composition 2 is irradiated with light such as UV, the photocurable The composition 2 is to have a shape of the partition wall while being fixed to the lower substrate (3). Conventionally, in order to form a partition wall, a partition material is directly applied onto a substrate or an electrode, and here, a lithography process is used to etch the partition wall into a desired shape, but according to the present invention, the mold and the photocurable composition (2) The hardening method of) is an indirect method of injecting the partition forming material into the mold 1 and attaching it to the substrate structure. This has the advantage that the bulkhead can be easily and easily formed in bulk, and the mold 1, which is an indirect mold frame, can be reused continuously. In addition, the reverse process of forming the desired shape by pressing the mold 1 after applying the photocurable composition 2 to the substrate is also possible.

The partition wall forming step S40 is a step of forming the partition wall by separating the lower electrode and the cured photocurable composition 2 from the mold 1. As shown in FIG. 6D, to separate the lower electrode and the cured photocurable composition 2 from the mold 1, the lower electrode and the cured photocurable composition 2 or the mold 1 are held up and down. In order to facilitate such separation, the mold 1 may further include a material such as a lubricant before injecting the photocurable composition 2 into the mold. The method of separating is not particularly limited. The partition wall is used to distinguish the cell unit while supporting the substrate and the electrode. In addition, the step of separating the cured photocurable composition (2) and the mold (1) to form a partition wall primer on the lower substrate (3) to enhance the adhesion between the lower substrate 3 and the photocured composition (2) You can also do it.

Filling step (S50) is a step of filling the charged particles in the cell formed by the partition wall. The charged particles used in the filling step (S50) is based on 100 parts by weight of a solvent containing either methanol or ethanol and water, 5 to 20 parts by weight of monomer, 0.01 to 0.5 parts by weight of synthetic initiator, 0.01 to 5 parts by weight of electrolyte And 0.01 to 5 parts by weight of the particle stabilizer.

Specifically, in the method for producing the charged particles of the present invention, the first embodiment includes the silica nanoparticles forming the external additive in the charged particles, and polymerizing the polymer particles together according to the non-emulsification polymerization method, thereby collectively The external additives are formed on the surface of the charged particles by chemical bonding using electrostatic attraction. In the second embodiment, first, polymer particles are prepared by dispersion polymerization from a composition having a composition excluding silica nanoparticles. And it is characterized by adding the silica nanoparticles to the resulting polymer particles and reacting, and then drying to produce charged particles. According to this, the silica nanoparticles adhere well to the surface of the polymer particles, and a charged particle having a small particle size distribution is formed.

First, a method for preparing charged particles according to the emulsion-free polymerization according to the first embodiment will be described. Polymerization of the polymer is largely performed by emulsion polymerization using surfactants such as sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB), dispersion polymerization, and suspension polymerization. Can be divided into In general, when the surfactant is used, small nanoparticles of 100 nm or less can be obtained, the particle size distribution is narrow, and the reaction rate is faster than dispersion and suspension polymerization. This is because by adding a ionic surfactant, micelles surrounding the polymer particles are formed to obtain a more stable colloidal phase.

However, in order to prepare charged particles, a process of reacting separate silica nanoparticles with the polymer particles thus formed is required, which increases the number of processes and requires cumbersome operations such as attaching a separate hydrophilic functional group to the formed polymer. , The inventors, etc. repeated experiments, to prepare the charged particles by performing a soap-free emulsion polymerization (hereinafter referred to as 'emulsification-free polymerization') without the surfactant, to charge the charged particles only in the polymer particle polymerization step It is proposed a manufacturing method which can obtain a high yield by reducing the number of working processes, which is economical.

According to the non-emulsification polymerization according to the present invention, the surfactant is not entered during the polymerization process, but the surfactant is added by the interaction thereof, including an ionic synthesis initiator or a functional group having ionic properties in the polymer chain to be polymerized. Similar levels of colloidal stabilization were achieved.

Such, the method for producing charged particles according to the first embodiment of the present invention, in the filling step (S50), includes a polymer polymerization step (S51), drying step (S52).

In the polymer polymerization step (S51), the charged particles dissolved in the cosolvent are mixed and dispersed. Then, the polymerization is carried out by stirring while maintaining a temperature of preferably 40 to 90 ° C, more preferably 60 to 75 ° C, and an inert gas such as nitrogen (N ₂ ) or argon (Ar) is supplied to the solvent. Oxygen removal step (S511) to remove the dissolved oxygen included is included, preferably 15 to 24 hours, more preferably 18 to 22 hours is carried out by the emulsion-free polymerization method.

In the drying step (S52) it is possible to dry the thus-charged charged particles, it can be carried out in accordance with the drying step of the conventional charged particle manufacturing method. For example, lyophilization can be performed. This may be used after cooling the mixed aqueous solution containing the polymerized polymer to -100 ° C to -10 ° C to solidify the material, and then lowering the pressure to 4.6torr or less to sublimate the water contained in the freeze powder. .

Such, the method for producing charged particles according to the second embodiment of the present invention, in the filling step (S50), includes a polymer polymerization step (S53), reaction step (S54), drying step (S55).

The polymer polymerization step (S53) is a charged particle, and instead of including a particle stabilizer for dispersion polymerization, it is configured in a form excluding silica nanoparticles, and then polymerized in the same manner as in the first embodiment.

The reaction step (S54) is a step of performing the reaction with a solution in which silica nanoparticles and a colorant are added to form an external additive on the surface of the formed polymer particles. This can be done using a catalyst according to the description of Applicant No. 10-2007-0128097 previously filed by the applicant.

Drying step (S55) proceeds to the step of drying the solution.

General details of the method for producing charged particles other than those described above can be found in the descriptions of the application Nos. 10-2006-98634, 10-2007-0003528, and 10-2007-29234 that the applicant has previously filed. Jun.

Finally, the bonding step S60 performed after the filling step S50 is performed by laminating the upper substrate 8 on the upper surface of the partition wall so that the upper electrode faces the lower electrode, as shown in FIG. 7. Step 4). 7 is a schematic diagram showing a process of bonding the upper substrate 8 and the lower substrate 4 in accordance with the present invention. The stacking and bonding method is placed so as to face the upper substrate 8 on which the upper electrode is formed and the lower substrate 4 to which the partition wall 7 formed by the photocurable composition using the mold is attached. The upper electrode and the lower electrode (not shown) are stacked in the vertical direction. The upper electrode and the lower electrode serve as a scan electrode and a data electrode to adjust the voltage of each cell.

Hereinafter, the preferable experimental example which manufactures the charged particle of this invention is described.

Experimental Example 1

In order to examine the effect of the cosolvent content ratio, styrene particles having been freed of impurities through a column (Aros Organics, Inc., aluminum oxide) as monomers were used, and KPS was used as a synthesis initiator. Polystyrene polymer particles were prepared by performing emulsion-free polymerization for 24 hours at 70 ° C. while changing to (a) 100: 1, (b) 90:10, and (c) 80:20. The size of the resulting polymer particles is as shown in FIG. In FIG. 9, it is a SEM photograph which shows the polymer particle superposed | polymerized by the solvent structure of said (a)-(c) from the left side.

As shown in FIG. 9, in the above three experiments, the size of the polystyrene polymer particles was 0.46 μm in the (a) experiment and 0.43 μm in the (c) experiment. There was no change. However, the uniformity (the diameter of the largest particles / the diameter of the smallest particles) was 1.022 to 1.006, all of which showed good results, especially as the ethanol content increased.

Experimental Example 2

Next, 0.1 g electrolyte (NaCl) was added to the composition, and the amounts of water and ethanol were changed to (a) 100: 1 and (b) 95: 5, and polystyrene was prepared in the same manner as in Experimental Example 1. The results are as shown in FIGS. 10 and 11A-11B.

As shown in the SEM photograph of FIG. 10 and the graph showing the weight average particle size relative to the water: ethanol content ratio in the solvent of FIG. 11A, both experiments showed a narrow particle distribution of about 1 μm or less. On the other hand, when the solvent ratio is 95: 5, the size of the polymer particles increases to about 2 μm, and as shown in FIG. 11A, a narrower particle distribution is shown. It is believed that this is a result of the small amount of electrolytes that facilitated nucleation and particle adsorption of styrene. However, in other experiments, experiments with large proportions of ethanol in the solvent showed a smaller particle size.

11B is a graph showing particle size and zeta potential according to solvent content ratio. The higher the ethanol ratio, the higher the zeta potential value, and the lower the particle stability.

[Experimental Example 3]

The effect on particle generation on the polymerization time in the reactor was investigated. As a monomer, methyl methacrylate (MMA, Aldrich, Inc.), from which impurities were removed through a column (Acros Organics, Inc., aluminum oxide), was used as a solvent without distilled water and methanol. As a synthetic initiator, polymer particles were prepared by emulsion-free polymerization using water-soluble KPS (Aldrich) without purification.

12A and 12B are graphs showing conversion rates and average particle sizes, respectively, according to temperature. As small primary particles were formed at the beginning of the polymerization and the polymerization time was longer, the primary particles grew to increase the diameter of the polymer particles, and it was confirmed that they had a uniform size distribution. Small particles of less than 400 nm were produced at the beginning of the polymerization, and after 24 hours of polymerization, the average particle size was 1.1 μm, showing a narrow size distribution.

In FIG. 13, polymethylmethacrylate (PMMA) particles prepared by changing the content ratio of methanol: water to (a) 100: 50, (b) 100: 40, (c) 100: 30, and (d) 100: 20 Size change was shown. From this, secondary particles are formed after 4 hours of polymerization, and primary particles and secondary particles are competitively grown at the time of polymerization, which has a bimodal or trimodal particle size distribution. It could be confirmed that the formed.

In addition, the decrease in the content of water in the non-emulsification polymerization tended to make it difficult to control the polymer particle size, and when using ethanol or acetone instead of methanol as a solvent, the polymer particles could not be obtained.

[Experimental Example 4]

Next, styrene particles having impurities removed through a column (Acros Organics, Aluminum Oxide) as monomers for the production of polystyrene polymer particles, methanol (99.5%, extra pure) as a cosolvent used with water grade, Samchun Chemical Co., Ltd. was used, and the particle stabilizer was PVP (K = 30, MW = 40,000, Kanto Chemical. Co. INC). Synthesis initiator using AIBN (98%, special grade, Samchun Chemical), to prepare the polymer particles by dispersion polymerization.

14 is a SEM image of the resulting particles by changing the solvent content ratio (methanol: water) to (a) 100: 0, (b) 95: 5, (c) 90:10, and (d) 85:15, respectively. It is shown. It can be seen that in the dispersion polymerization using a fat-soluble initiator, the more the water is added to the solvent, the smaller the size of the produced polymer particles is. As a result, it was confirmed that the solubility parameter of the dispersion medium is an important variable for determining the size and distribution of the polymer particles.

Although preferred embodiments of the present invention have been described above, the present invention may use various changes, modifications, and equivalents. It is clear that the present invention can be applied in the same manner by appropriately modifying the above embodiments. Accordingly, the above description does not limit the scope of the invention as defined by the limitations of the following claims.

1 is a cross-sectional view showing a cell structure for a collision charging type electronic paper according to the prior art

Figure 2 is a cross-sectional view showing the particles used in the electronic paper according to the prior art

3 is a cross-sectional view illustrating a cell structure of an electronic paper display device according to an embodiment of the present invention.

4A to 4D are flowcharts illustrating a process of forming a partition wall using photolithography in an electronic paper display device according to the prior art.

5 is a flowchart sequentially illustrating a method of manufacturing the electronic paper display device of the present invention.

6A to 6D are flowcharts illustrating a process of forming a partition of an electronic paper display device using a mold according to the present invention.

7 is a cross-sectional view showing a state in which the substrate and the partition wall of the electronic paper display device is bonded according to the present invention.

8 is a cross-sectional view of an electronic paper display device manufactured according to the present invention.

9 is a SEM photograph of polystyrene according to Experimental Example 1 of the present invention.

10 is a SEM photograph of polystyrene according to Experimental Example 2 of the present invention.

11A and 11B are graphs showing particle size and zeta potential according to solvent content ratio in Experimental Example 2 of the present invention.

12a and 12b are graphs showing the conversion rate and the average particle size according to temperature in Experimental Example 3 of the present invention, respectively.

13 is a SEM photograph of the polymethyl methacrylate according to Experiment 3 of the present invention

14 is a SEM photograph of polystyrene according to Experimental Example 4 of the present invention.

<Description of Signs of Major Parts of Drawing>

 1: mold 2: photocurable composition

 3, 4: lower substrate 5: lower electrode

 7: bulkhead 8: upper substrate

 9: charged particle

11: polymer particle 12: charge control agent

13: Dye / dye 14: External additive

10: upper substrate 20: lower substrate

30: upper electrode 40: lower electrode

50: bulkhead 60,70: charged particles

100: substrate 200: electrode

300: photoresist 400: pattern

500: bulkhead

110: upper substrate 120: lower substrate

130: upper electrode 140: lower electrode

150: bulkhead 160,170: charged particles

Claims (8)

In an electronic paper display device having a partition wall forming a cell between an upper substrate and a lower substrate, and filled with charged particles in the cell, The upper substrate and the lower substrate disposed to face each other at a predetermined interval; An upper electrode and a lower electrode formed to be inscribed on the lower substrate and the upper substrate, respectively; Barrier ribs forming a cell by dividing pixels between the upper electrode and the lower electrode; It comprises a; charged particles filled between the partition wall, The charged particle is characterized in that it comprises 5 to 20 parts by weight of monomer, 0.01 to 0.5 parts by weight of synthetic initiator, and 0.01 to 2 parts by weight of electrolyte based on 100 parts by weight of a solvent containing either methanol or ethanol and water. Electronic paper display device. The method of claim 1, The solvent consists of water and ethanol, The monomer is styrene or methyl methacrylate, The electrolyte is any one of sodium chloride (NaCl), sodium bicarbonate (NaHCO ₃ ), sodium pyrosulfate (Na ₂ S ₂ O ₇ ) or potassium carbonate (K ₂ CO ₃ ), The synthesis initiator is any one of potassium persulfate (KPS) or 2,2'-azobis (isobutyronitrile), The charged particle further comprises at least one of silicon nanoparticles, a charge control agent, a particle stabilizer and a colorant. The method according to claim 1 or 2, The partition wall is made of a U-shaped or V-shaped uneven shape, the electronic paper display device, characterized in that the interval between the unevenness is 0㎛ to 50㎛. An electrode forming step of forming a lower electrode on the lower substrate and forming an upper electrode on the upper substrate; An application step of preparing a mold having a concave-convex structure and applying a photocurable composition on the concave-convex structure; Positioning the lower substrate so that the injected photocurable composition and the lower electrode face each other, and then curing the photocurable composition by irradiating UV with the photocurable composition; A barrier rib forming step of separating the lower electrode and the cured photocurable composition from a mold to form a barrier rib; A filling step of filling charged cells in a cell formed by the partition wall; And laminating the upper substrate on the upper surface of the partition wall so that the upper electrode faces the lower electrode, and bonding the upper substrate to the lower substrate. The charged particles of the filling step is 5 to 20 parts by weight of monomer, 0.01 to 0.5 parts by weight of synthetic initiator, 0.01 to 5 parts by weight of electrolyte, and particle stabilizer based on 100 parts by weight of a solvent containing either methanol or ethanol and water. It comprises 0.01 to 5 parts by weight, The filling step may include mixing and dispersing the charged particles, and polymerizing the dispersed solution by polymerizing the dispersed solution at 40 to 90 ° C. for 15 to 26 hours to produce polymer particles; A reaction step of reacting the polymer particles with a solution containing silica nanoparticles and a colorant; Method of manufacturing an electronic paper display device comprising a; drying step of drying the solution. The method of claim 4, wherein The uneven structure of the mold in the coating step is made of a U-shaped or V-shaped, the method of manufacturing an electronic paper display device, characterized in that the interval between the unevenness is 0㎛ 50㎛. The method of claim 4, wherein The photocurable composition is a method of manufacturing an electronic paper display device, characterized in that the ester type or ether type polymer in which acrylyl or allyl system is bonded to the sock end of polyethylene glycol (PEG) or polypropylene glycol (PPG). The method of claim 4, wherein The polymer polymerization step of supplying an inert gas to the charged particles, the oxygen removing step of removing the dissolved oxygen contained in the solvent; manufacturing method of an electronic paper display device further comprising. In the structure of an electronic paper display device, A lower electrode formed to be in contact with the lower substrate and the lower substrate; Barrier ribs formed in the form of U-shaped or V-shaped unevenness, and having an interval between unevennesses of 0 µm to 50 µm; A cell formed by the partition wall; Charged particles filled in the cell; The structure of the electronic paper display device, characterized in that stacked in the order of the upper electrode and the upper substrate formed in contact with the upper substrate;

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