JP5842399B2 - Electrophoretic display device, method for manufacturing electrophoretic display device, and electronic apparatus - Google Patents

Description

  The present invention relates to an electrophoretic display device, a method for manufacturing an electrophoretic display device, and an electronic apparatus.

As an electrophoretic display device of this type, a device in which a space between a pair of substrates is divided into a plurality of cells by partition walls, and a dispersion liquid in which electrophoretic particles are dispersed is filled in the cells (patent) Reference 1).
For example, Patent Document 1 discloses a technique for sealing a partition wall filled with a dispersion using a sealing film made of an ultraviolet curable resin.

JP 2004-317830 A

However, in the electrophoretic display device disclosed in Patent Document 1, it is difficult to apply an ultraviolet curable resin while controlling the film thickness at a submicron level. The liquid must be sealed. Then, in order to move the electrophoretic particles in the dispersion in a predetermined direction, there is a problem that the driving voltage applied between the pair of electrodes is increased.
Further, in the conventional sealing film, the sealing film thickness at the center of the pixel covered by the sealing film is thinner than the sealing film thickness at the pixel edge, and the voltage at the pixel center is higher than that at the pixel edge. There is also a problem that it is difficult to control the driving voltage in the pixel because there is a problem that the electrophoretic particles are lowered and concentrate in the center of the pixel.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

Application Example 1 An electrophoretic display device according to this application example includes a substrate, a partition that divides a region on the substrate into a plurality of cells, a dispersion liquid that includes electrophoretic particles filled in the plurality of cells, A sealing film that seals the plurality of cells, and the sealing film includes an ionic first polymerizable surfactant and ions having opposite polarities with respect to the first polymerizable surfactant. Second polymerizable surfactant, third polymerizable surfactant, polymer film in which a polymerizable monomer is polymerized between the second polymerizable surfactant and the third polymerizable surfactant, , Including.

  According to this configuration, the ionic first polymerizable surfactant and the second polymerizable surfactant having opposite polarities are strongly adsorbed to each other and are evenly arranged on the surface of the dispersion. Become. Thereby, the film thickness of the polymer film obtained by polymerizing the polymerizable monomer disposed between the second polymerizable surfactant and the third polymerizable surfactant tends to be uniform. Therefore, by adjusting the amount of the polymerizable monomer, a plurality of cells can be sealed, and a relatively thin sealing film having a uniform film thickness can be realized. That is, an electrophoretic display device that can be driven at a low voltage and has excellent display quality can be provided.

Application Example 2 In the electrophoretic display device according to the application example described above, the third polymerizable surfactant is an ionic polymerizable surfactant.
According to this configuration, since the first to third polymerizable surfactants are all ionic, the first to third in aqueous solution with respect to the substrate having a plurality of cells filled with the dispersion. A polymerizable surfactant can be arranged. That is, an electrophoretic display device having both productivity and reliability can be provided.

  Application Example 3 In the electrophoretic display device according to the above application example, the third polymerizable surfactant may be a nonionic polymerizable surfactant.

Application Example 4] Another electrophoretic display device of this application example, the dispersion comprising a substrate, a partition wall for dividing a region on the substrate into a plurality of cells, the electrophoretic particles filled in the plurality of cell Le comprising a liquid and a sealing film to seal the plurality of cells, said sealing film, Lee and on of the first polymerizable surfactant, opposite to the first polymerizable surfactant An ionic second polymerizable surfactant having polarity, and a polymer film obtained by polymerizing a hydrophobic monomer and an ionic hydrophilic monomer with respect to the second polymerizable surfactant. To do.

  According to this configuration, since an ionic hydrophilic monomer is used, a thin sealing film having a relatively uniform film thickness can be realized without using a third polymerizable surfactant. That is, it is possible to provide an electrophoretic display device that can be driven at a low voltage and has excellent display quality with a simple configuration.

Application Example 5 A method for manufacturing an electrophoretic display device according to this application example includes electrophoresis including a partition partitioning a plurality of cells on a substrate and a dispersion liquid containing electrophoretic particles filled in the cells. a method of manufacturing a display device, a first step of supplying the ions of the first polymerizable surfactant to the liquid surface of the dispersion filled in the cell, before Symbol first polymerizable surfactant fourth supplying a second step of supplying the ions of the second polymerizable surfactant, a third step of supplying a heavy polymerizable monomer, a third polymerizable surfactant having a polarity opposite to that And a fifth step of forming a sealing film that seals the plurality of cells by polymerizing the polymerizable monomer.

  According to this method, in the second step, the second polymerizable surfactant having the opposite polarity to the first polymerizable surfactant disposed on the surface of the dispersion is strongly adsorbed, and the surface of the dispersion Evenly arranged. In the fifth step, the polymerizable monomer disposed between the second polymerizable surfactant and the third polymerizable surfactant is polymerized to form a sealing film having a uniform film thickness. By adjusting the amount of the polymerizable monomer, a plurality of cells can be sealed, and a relatively thin sealing film having a uniform film thickness can be formed. That is, an electrophoretic display device that can be driven at a low voltage and has excellent display quality can be manufactured.

  Application Example 6 In the method for manufacturing an electrophoretic display device according to the application example, the first to fourth steps include the first polymerizable surfactant, the second polymerizable surfactant, and the polymerizable monomer. The third step is carried out by immersing the substrate filled with the dispersion in the aqueous solution into which each of the third polymerizable surfactants is introduced, and the fifth step is performed in the aqueous solution. It is characterized by being carried out by introducing a polymerization initiator.

  According to this method, since the first polymerizable surfactant and the second polymerizable surfactant are ionic, the first polymerizable surfactant and the second polymerizable surfactant strongly bonded to the surface of the dispersion in the aqueous solution. The bipolymerizable surfactant can be arranged evenly. Further, by introducing the third polymerizable surfactant into the aqueous solution, the polymerizable monomer is evenly disposed between the second polymerizable surfactant and the third polymerizable surfactant. Then, if a polymerization initiator is introduced into the aqueous solution in the fifth step, the polymerizable monomer is polymerized while being held between the second polymerizable surfactant and the third polymerizable surfactant. A sealing film can be formed. That is, since each process can proceed in water, it is difficult to be affected by the surrounding environment, and a uniform and thin sealing film can be stably formed.

  A typical example will be described. In water, for example, an anionic first polymerizable surfactant is arranged on a dispersion containing electrophoretic particles. Subsequently, the cationic second polymerizable surfactant is adsorbed on the anionic first polymerizable surfactant. Furthermore, a polymerizable monomer and an anionic third polymerizable surfactant are introduced. By the above method, the polymerizable monomer and the anionic third polymerizable surfactant are arranged on the dispersion liquid in which the anionic first polymerizable surfactant and the cationic second polymerizable surfactant are arranged. To do. The polymerizable monomer is sandwiched between the second polymerizable surfactant on the dispersion and the third polymerizable surfactant introduced later. In the arrangement state, the second and third polymerizable surfactants and the polymerizable monomer are polymerized, and the formed polymer film seals the dispersion.

  The ionic first polymerizable surfactant is arranged on the dispersion with the hydrophobic group facing the dispersion and the ionic group (charged group) facing the aqueous solution. When the first polymerizable surfactant is anionic, the second polymerizable surfactant is a cationic polymerizable surfactant. At that time, the charged group of the first polymerizable surfactant and the charged group of the second polymerizable surfactant are adsorbed by a strong ionic bond. The polymerizable monomers are arranged so as to exist between the hydrophobic part of the cationic second polymerizable surfactant and the hydrophobic part of the anionic third polymerizable surfactant.

  After forming the laminated structure of the third polymerizable surfactant and the polymerizable monomer, a polymer film can be formed on the dispersion by introducing a polymerization initiator and polymerizing the polymerizable monomer.

  The film thickness of the film formed on the dispersion is on the order of submicron to micron. Therefore, an electrophoretic display device that can be driven at a low voltage can be provided.

  By adjusting the amount of the third polymerizable surfactant or polymerizable monomer, the film thickness of the polymer film can be controlled in submicron units. In other words, an electrophoretic display device capable of controlling the drive voltage can be manufactured.

  The combination of polarities in the ionic surfactant can be reversed. In the above example, the anionic polymerizable surfactant, the cationic polymerizable surfactant, and the anionic polymerizable surfactant were used from the dispersion side, but the cationic polymerizable surfactant was used from the dispersion side. An anionic polymerizable surfactant or a cationic polymerizable surfactant may be used.

The polymerizable surfactant used in this application example is an ionic polymerizable surfactant having either a positive or negative charge sign. There are three types of polymerizable surfactants. Examples of combinations of ionic species of the first to third polymerizable surfactants are as follows: the first is anionic, the second is cationic, the third is anionic, or the first is cationic and the second is an anion The third is cationic.
Furthermore, the third polymerizable surfactant is not limited to being ionic, and can retain a polymerizable monomer between the nonionic and ionic second polymerizable surfactant. .

Application Example 7 Another method of manufacturing an electrophoretic display device according to this application example includes a partition wall that partitions a plurality of cells on a substrate, and a dispersion liquid that includes electrophoretic particles filled in the cell. a method of manufacturing an electrophoretic display device, a first step of supplying the ions of the first polymerizable surfactant to the liquid surface of the dispersion filled in the cell, before Symbol first polymerizable surfactant a second step of supplying the ions of the second polymerizable surfactant having a polarity opposite to the active agent, after supplying the hydrophobicity monomer, and a third step of supplying the ionic hydrophilic monomer, And a fourth step of polymerizing the hydrophobic monomer and the ionic hydrophilic monomer to form a sealing film for sealing the plurality of cells.

  According to this method, since the hydrophilic monomer is ionic, a relatively uniform and thin sealing film can be formed without using the third polymerizable surfactant. That is, it is possible to manufacture an electrophoretic display device having a simple configuration that can be driven at a low voltage and has excellent display quality.

Application Example 8 In another method of manufacturing an electrophoretic display device according to the application example, the first to third steps include the first polymerizable surfactant, the second polymerizable surfactant, and the hydrophobic The fourth step is performed in the aqueous solution by immersing the substrate filled with the dispersion liquid in the aqueous solution into which the ionic monomer and the ionic hydrophilic monomer are respectively introduced. It is characterized by being carried out by introducing a polymerization initiator.
According to this method, since the first polymerizable surfactant and the second polymerizable surfactant are ionic, the first polymerizable surfactant and the second polymerizable surfactant strongly bonded to the surface of the dispersion in the aqueous solution. The bipolymerizable surfactant can be arranged evenly. In addition, by introducing an ionic hydrophilic monomer into the aqueous solution, a polymerizable monomer composed of a hydrophobic monomer and a hydrophilic monomer combined with the second polymerizable surfactant can be arranged evenly. And if a polymerization initiator is introduce | transduced into aqueous solution in a 4th process, the polymeric monomer will be superposed | polymerized in the state connected with the 2nd polymeric surfactant, and the polymerized sealing film can be formed. That is, since each process can proceed in an aqueous solution, a uniform and thin sealing film can be stably formed which is hardly affected by the surrounding environment.

Application Example 9 An electronic apparatus according to this application example includes the electrophoretic display device according to the application example described above.
According to this configuration, since the electrophoretic display device according to the application example is provided, various electronic devices such as a wristwatch, an electronic paper, an electronic notebook, a mobile phone, and a portable audio device capable of performing high-quality display are provided. Equipment can be realized.

1 is a schematic cross-sectional view illustrating a configuration of an electrophoretic display device according to Embodiment 1. FIG. FIG. 3 is an arrangement diagram of partition walls and a dispersion when the electrophoretic display device according to Embodiment 1 is viewed from directly above. 2 is a schematic cross-sectional view showing a relative positional relationship between a polymerizable surfactant and a polymerizable monomer on a dispersion in the electrophoretic display device according to Embodiment 1. FIG. The flowchart which shows the manufacturing method of an electrophoretic display device. (A)-(e) is a schematic sectional drawing which shows the manufacturing method of an electrophoretic display device. (F)-(h) is a schematic sectional drawing which shows the manufacturing method of an electrophoretic display device. FIG. 6 is a schematic cross-sectional view illustrating a relative positional relationship between a polymerizable surfactant and a polymerizable monomer on a dispersion liquid in an electrophoretic display device according to Embodiment 2. The perspective view which shows the structure of the electronic paper as an example of an electronic device. The perspective view which shows the structure of the electronic notebook as an example of an electronic device. FIG. 6 is a schematic cross-sectional view illustrating a configuration of an electrophoretic display device according to a modification.

  Embodiments of an electrophoretic display device according to the present invention will be described below with reference to FIGS. In the following drawings, the scale of each layer and each member is made different from the actual scale so that each layer and each member can be recognized.

(Embodiment 1)
<Electrophoretic display device>
First, a schematic configuration of the electrophoretic display device according to the present embodiment will be described with reference to FIGS. FIG. 1 is a schematic cross-sectional view showing a configuration of an electrophoretic display device according to Embodiment 1, FIG. 2 is a diagram of the electrophoretic display device viewed from directly above, and FIG. 3 is a diagram showing polymerization with a polymerizable surfactant on a dispersion liquid. It is a schematic cross section which shows the relative positional relationship with a property monomer.

As shown in FIG. 1, the electrophoretic display device 100 of the present embodiment includes a cell matrix 10 in which a dispersion 20 containing electrophoretic particles 21 is filled in each of a plurality of cells 13, an element substrate 50, a counter substrate 60, Etc.
The element substrate 50 includes a flat substrate body 52 and a plurality of pixel electrodes 51 formed on one surface of the substrate body 52. The substrate body 52 is provided with a thin film transistor (TFT: Thin Film Transistor; not shown) for driving the pixel electrode 51 for each pixel arranged in a matrix, for example, in the display area. More specifically, the substrate body 52 has a laminated structure in which wirings such as TFTs for driving the pixel electrodes 51, scanning lines, and data lines are formed.

  The substrate body 52 is made of, for example, a substrate made of an insulating resin material such as polycarbonate (PC) or polyethylene terephthalate (PET) (that is, a resin substrate), or an inorganic substrate such as a transparent glass substrate.

  The pixel electrode 51 is made of a conductive material such as indium tin oxide (ITO).

  The counter substrate 60 includes a flat substrate body 62 and a counter electrode 61 formed on one surface of the substrate body 62. Similarly to the substrate body 52 of the element substrate 50, the substrate body 62 is made of, for example, a substrate made of an insulating resin material such as polycarbonate or polyethylene terephthalate (that is, a resin substrate) or an inorganic substrate such as a transparent glass substrate. Become.

  The counter electrode 61 is made of a light-transmitting conductive material such as indium tin oxide (ITO), for example, and is provided on the substrate body 62 so as to face the plurality of pixel electrodes 51 of the element substrate 50. ing. That is, the counter electrode 61 is a common electrode across a plurality of pixels.

The cell matrix 10 includes partition walls 12 that partition a plurality of cells 13. Each cell 13 is injected with a dispersion 20 in which electrophoretic particles 21 are dispersed in a dispersion medium 22 such as Isopar (registered trademark).
The dispersion liquid 20 is sandwiched between the element substrate 50 and the counter substrate 60 while being filled in the plurality of cells 13 of the cell matrix 10.

Specifically, the cell matrix 10 includes a flat plate portion 11 and a partition wall 12 disposed on one surface of the flat plate portion 11.
A plurality of cells 13 are formed by dividing the space on the flat plate portion 11 by the partition walls 12. The partition wall 12 has, for example, a square lattice-like planar shape when viewed in plan on the flat plate portion 11 (see FIG. 2). The flat plate portion 11 and the partition wall 12 are integrally formed.
The cell matrix 10 (that is, the flat plate portion 11 and the partition wall 12) is made of a resin material such as an epoxy resin, an acrylic resin, a urethane resin, a melamine resin, or a phenol resin, for example.
The planar shape of the partition walls 12 is not limited to a square lattice shape, and may be, for example, a honeycomb lattice shape or a triangular lattice shape. In this embodiment, the partition 12 is integrally formed with the flat plate portion 11 as an example. However, the partition 12 and the flat plate portion 11 are formed separately, and one surface of the flat plate portion 11 is formed. The partition 12 may be fixed on the top.

  Further, since the flat plate portion 11 is formed on the pixel electrode 51, the pixel electrode 51 does not directly touch the dispersion liquid 20. Therefore, problems such as the erosion of the pixel electrode 51 by the dispersion liquid 20 are prevented. When the pixel electrode 51 is configured using a material that is chemically stable with respect to the dispersion liquid 20, the cell matrix 10 may be configured by only the partition walls 12. That is, the partition wall 12 may be disposed on the element substrate 50 without using the flat plate portion 11. Thereby, the drive voltage applied between the pixel electrode 51 and the counter electrode 61 in order to move the electrophoretic particles 21 of the dispersion 20 can be reduced.

  In the present embodiment, the flat plate portion 11 and the partition 12 are formed so that one cell 13 is formed on one pixel electrode 51, but the present invention is not limited to this. For example, the flat plate portion 11 and the partition 12 may be formed so that a plurality of cells 13 are formed on one pixel electrode 51.

The dispersion liquid 20 is a liquid in which a plurality of electrophoretic particles 21 are dispersed in a dispersion medium 22.
The electrophoretic particles 21 are, for example, pigment particles, resin particles, or composite particles thereof. Examples of the pigment constituting the pigment particles include black pigments such as aniline black and carbon black, and white pigments such as titanium oxide and antimony oxide. Examples of the resin material constituting the resin particles include acrylic resin, urethane resin, urea resin, epoxy resin, polystyrene, polyester, and the like. Examples of composite particles include those in which the surface of pigment particles is coated with a resin material or other pigment, the surface of resin particles coated with a pigment, or a mixture of pigment and resin material mixed in an appropriate composition ratio. There are particles and so on. The electrophoretic particles 21 made of these various materials are dispersed in the dispersion medium 22 in a positively or negatively charged state, for example.

  Further, the electrophoretic particles 21 dispersed in the dispersion 20 are not limited to one kind of charged particle. For example, one of two types of charged particles of white and black having different polarities when charged, or one of two types of electrophoretic particles having different colors may be charged particles.

  The dispersion medium 22 is a lipophilic hydrocarbon solvent, and includes, for example, Isopar (registered trademark) which is an isoparaffin solvent. That is, the dispersion medium 22 is a liquid containing any one of Isopar E, Isopar G, Isopar H, and Isopar L, or a liquid in which two or more of these are mixed, or any of these. It is a liquid in which one or more types and other types of hydrocarbon solvents are mixed.

  The plurality of cells 13 in the cell matrix 10 are sealed by a sealing film 30 provided so as to face the flat plate portion 11 with the partition walls 12 interposed therebetween.

As shown in FIG. 3, the sealing film 30 includes, for example, an anionic first polymerizable surfactant 31 and a cationic second polymerizable interface, which are sequentially arranged so as to cover the partition wall 12 and the dispersion liquid 20. An activator 32, a polymer film 36, and an anionic third polymerizable surfactant 33 are included.
In FIG. 3, the counter substrate 60 disposed to face the element substrate 50 is not shown.

The polymer film 36 is formed by a polymerization reaction of a polymerizable monomer. In the polymerization reaction, a polymerization initiator such as potassium persulfate (KPS) is used.
As will be described in detail later, the sealing film 30 has a polymer film 36 in which a polymerization initiator is added to a polymerizable monomer sandwiched between ionic polymerizable surfactants to cause a polymerization reaction. Such formation of the polymer film 36 is called admicelle polymerization (AMP).
The film thickness of the polymer film 36 obtained after polymerization can be controlled in submicron units by uniformly arranging one ionic polymerizable surfactant sandwiching the polymerizable monomer on the surface of the dispersion 20. is there.
Moreover, it is preferable that the polymer film 36 exhibits hydrophobicity so as to suppress intrusion of moisture and gas from the viewpoint of ensuring the reliability of the electrophoretic display device 100. Therefore, it is preferable to use a hydrophobic monomer as the polymerizable monomer.

  The hydrophobic monomer has at least a hydrophobic group and a polymerizable group in its structure, and the hydrophobic group is selected from the group consisting of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. Can be illustrated. Examples of the aliphatic hydrocarbon group include a methyl group, an ethyl group, and a propyl group. Examples of the alicyclic hydrocarbon group include a cyclohexyl group, a dicyclopentenyl group, a dicyclopentanyl group, and an isobornyl group, and an aromatic hydrocarbon group. Examples thereof include a benzyl group, a phenyl group, and a naphthyl group. The polymerizable group is an unsaturated hydrocarbon group capable of radical polymerization, and is preferably selected from the group consisting of a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, a propenyl group, a vinylidene group, and a vinylene group. .

The anionic first polymerizable surfactant 31 includes, in its structure, a hydrophobic group 31a, a polymerizable group 31b, and a hydrophilic group that are easily compatible with the dispersion medium 22 that is a lipophilic hydrocarbon solvent. Specific examples thereof include anionic allyl derivatives as described in JP-B-49-46291, JP-B-1-24142, or JP-A-62-104802. Anionic propenyl derivatives as described in JP-A-62-221431, anionic acrylics as described in JP-A-62-34947 or JP-A-55-11525 Examples thereof include acid derivatives and anionic itaconic acid derivatives as described in JP-B No. 46-34898 or JP-A No. 51-30284.
Preferred examples of the anionic group (charged group) include those selected from the group of sulfonic acid groups, sulfinic acid groups, carboxyl groups, carbonyl groups, and salts thereof. Typically, the hydrophobic group includes an acrylic group, the hydrophilic group includes ethylene oxide, and the anionic group includes a sulfone group.
Moreover, since the 1st polymeric surfactant 31 is equipped with the hydrophobic group, it can be arrange | positioned with affinity to the surface also with respect to the resin-made partition 12 mentioned above.
In addition, the 1st polymeric surfactant 31 is not limited to containing a hydrophilic group, The thing of the structure containing a polymeric group, a hydrophobic group, and a charged group is also employable.

  The cationic second polymerizable surfactant 32 having a polarity opposite to that of the first polymerizable surfactant 31 includes, for example, a hydrophobic group 32a, a polymerizable group 32b, and a hydrophilic group. Specific examples include dimethylaminoethyl methyl methacrylate methacrylate, dimethylaminoethyl benzyl methacrylate methacrylate, methacryloyloxyethyltrimethylammonium chloride, diallyldimethylammonium chloride, 2-hydroxy-3-methacryloxypropyltrimethylammonium chloride, and the like. Can be mentioned.

The cationic group (charged group) of the cationic second polymerizable surfactant 32 is a cationic selected from the group consisting of a primary amine cation, a secondary amine cation, a tertiary amine cation, and a quaternary ammonium cation. Groups are preferred. As the primary amine cation, a monoalkylammonium cation (RNH3 ⁺ ) or the like, as the second amine cation, a dialkylammonium cation (R2NH2 ⁺ ) or the like, as the tertiary amine cation, a trialkylammonium cation (R3NH ⁺ ) or the like, Examples of the quaternary ammonium cation include (R4N ⁺ ). Here, R is a hydrophobic group 32a and a polymerizable group 32b, and examples thereof include those shown below. Examples of the counter anion of the above-mentioned cationic group include Cl ⁻ , Br ⁻ and I ⁻ .
The hydrophobic group 32a is preferably selected from the group consisting of an alkyl group, an aryl group, and a group in which these are combined.

The polymerizable group 32b is preferably an unsaturated hydrocarbon group, and more specifically selected from the group consisting of a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, a propenyl group, a vinylidene group, and a vinylene group. Is preferred. Among these, an acryloyl group and a methacryloyl group can be exemplified as preferable examples.
Similar to the first polymerizable surfactant 31, the second polymerizable surfactant 32 is not limited to containing a hydrophilic group, and includes a hydrophobic group 32a, a polymerizable group 32b, and a charged group. A configuration can also be adopted. From the viewpoint of reducing the thickness of the sealing film 30 obtained after the polymerization as much as possible, it is desirable to use a polymerizable surfactant having a simple structure without including an unnecessary structure.

  As the anionic third polymerizable surfactant 33, those mentioned as the above-mentioned anionic first polymerizable surfactant 31 can also be suitably used. Moreover, it is not limited to containing a hydrophilic group like the 1st polymeric surfactant 31, The thing of the structure containing a polymeric group, a hydrophobic group, and a charging group can also be employ | adopted.

  As described above, according to the electrophoretic display device 100 according to this embodiment, the dispersion liquid 20 in the cell 13 is sealed with the polymer film 36 whose film thickness can be controlled by the charged amount of the polymerizable monomer. Therefore, the sealing material can be used efficiently. In addition, since the film thickness of the sealing film 30 can be controlled from the submicron level to the micrometer level, it is easy to realize a low drive voltage in electrophoretic display. For this reason, it becomes possible to increase the degree of freedom in the display drive design of the electrophoretic display device 100, and display with low power consumption, and further power saving of, for example, electronic paper using the electrophoretic display device 100. Is possible.

  The first polymerizable surfactant 31 and the second polymerizable surfactant 32 only have to have different polarities, and if one is cationic, the other is an anionic polymerizable surfactant. Can do. Similarly, if one is anionic, the other can be a cationic surfactant.

  As described above, since the first polymerizable surfactant 31 to the third polymerizable surfactant 33 are ionic, the sealing film 30 is formed using an aqueous solution in which these polymerizable surfactants are dispersed. Can be formed. Hereinafter, a method for manufacturing the electrophoretic display device 100 of the present embodiment will be described.

<Method for Manufacturing Electrophoretic Display Device>
A method for manufacturing the electrophoretic display device 100 of the present embodiment will be described with reference to FIGS. FIG. 4 is a flowchart illustrating a method for manufacturing an electrophoretic display device, and FIGS. 5A to 5E and 6F to 6H are schematic cross-sectional views illustrating a method for manufacturing the electrophoretic display device.

  As shown in FIG. 4, the manufacturing method of the electrophoretic display device 100 of this embodiment includes a partition wall forming step (step S1), a dispersion filling step (step S2), and a first polymerizable surfactant arranging step. (Step S3), placement step of second polymerizable surfactant (Step S4), placement step of polymerizable monomer (Step S5), placement step of third polymerizable surfactant (Step S6), polymerization step (Step S7).

  More specifically, in the partition formation step of step S1, as shown in FIG. 5A, the partition 12 including the flat plate portion 11 is formed using a photolithography method or the like. The height of the partition wall 12 is about 1 μm to 100 μm, and the width of the partition wall 12 is about 5 μm to several tens of μm. As described above, the flat plate portion 11 has a thickness of about several μm in consideration of an increase in driving voltage.

  In the dispersion filling step of step S2, as shown in FIG. 5B, the dispersion 20 is filled into the cells 13 surrounded by the partition walls 12 by, for example, a printing method using a screen or an ejection method such as inkjet. In order to improve the filling property of the dispersion liquid 20 into the cell 13, the substrate body 52 may be subjected to an activation process such as exposure to ozone generated by irradiation of ultraviolet rays.

  In the step of arranging the first polymerizable surfactant in step S3, as shown in FIG. 5C, first, the element substrate 50 filled with the dispersion liquid 20 is inverted and then immersed in the aqueous phase. At that time, the dispersion 20 in the cell 13 is held without being dispersed in the aqueous phase 70 by capillary force or the interaction between the partition wall 12 and the dispersion 20. Subsequently, as shown in FIG. 5 (d), by introducing the first polymerizable surfactant 31 into the aqueous phase 70, the first polymerizable surfactant 31 is simply applied to the surface of the dispersion 20 or the partition wall 12. A molecular film is formed.

In the arrangement step of the second polymerizable surfactant in step S4, as shown in FIG. 5 (e), the second polymerizable surfactant 32 having a charge opposite to that of the first polymerizable surfactant 31 is added to the water. Introduce into phase 70 and place. In step S3, since the monomolecular film of the first polymerizable surfactant 31 is formed on the surface of the dispersion 20 or the partition wall 12, the second polymerizable surfactant having the same amount as the first polymerizable surfactant 31 is formed. Agent 32 can be placed in an ionic attractive interaction. The first polymerizable surfactant 31 and the second polymerizable surfactant 32 are preferably arranged in a monomolecular layer. The number of molecules of the polymerizable surfactant for coating the surface of the dispersion 20 or the partition wall 12 is determined by the substrate area. For example, when a 10 cm square substrate is used, the aqueous phase 70 is added at 1 × 10 ⁻⁵ mol / What is necessary is just to adjust to the polymeric surfactant aqueous solution of the density | concentration about L (liter).

In the arrangement step of the polymerizable monomer in step S5, as shown in FIG. 6 (f), a predetermined amount of the hydrophobic monomer 35 as the polymerizable monomer is put into the aqueous phase 70 and slowly dispersed. The hydrophobic monomer 35 is disposed in the vicinity of the second polymerizable surfactant 32 due to the hydrophobic interaction. The concentration of the hydrophobic monomer 35 is also determined by the substrate area. For example, when obtaining a film thickness of about several hundreds of nanometers on a 10 cm square substrate, the hydrophobic monomer 35 is added at a concentration of about 1 × 10 ⁻² mol / L (liter). The hydrophobic monomer 35 may be disposed in the second polymerizable surfactant 32 by being dispersed in the aqueous phase 70.

In the step of arranging the third polymerizable surfactant in step S6, as shown in FIG. 6G, the ionic third polymerizable surfactant 33 is introduced into the aqueous phase 70 into the hydrophobic monomer 35. To arrange. The number of molecules of the third polymerizable surfactant 33 is determined by the area of the substrate. For example, with a 10 cm square substrate, the concentration of the third polymerizable surfactant 33 in the aqueous phase 70 may be about 1 × 10 ⁻³ mol / L (liter). Thereby, a micelle structure composed of the third polymerizable surfactant 33 and the hydrophobic monomer 35 is formed on the dispersion 20 and the partition wall 12.

In the polymerization step of step S7, as shown in FIG. 6 (h), in order to form this micelle structure into a polymer film, for example, the aqueous phase 70 is heated to about 50 ° C. to 80 ° C., and then 1 × 10 ^−3. The polymerization reaction is carried out while introducing a polymerization initiator 80 composed of an aqueous potassium persulfate solution of about mol / L (liter) into the aqueous phase 70. As a result, as shown in FIG. 3, the hydrophobic monomer 35 is polymerized by the second polymerizable surfactant 32 between the second polymerizable surfactant 32 and the third polymerizable surfactant 33. Polymerization is performed in a state where the group 32b and the polymerizable group 33b of the third polymerizable surfactant 33 are combined. In the first polymerizable surfactant 31, the polymerizable groups 31 b are polymerized in the vicinity of the surface of the dispersion 20. That is, the polymer film 36 is uniformly formed on the dispersion 20 and the partition walls 12. By using such a manufacturing method, the sealing film 30 can be formed with submicron accuracy.

(Embodiment 2)
<Other electrophoretic display devices>
Next, another electrophoretic display device of this embodiment will be described with reference to FIG. FIG. 7 is a schematic cross-sectional view showing the relative positional relationship between the polymerizable surfactant and the polymerizable monomer on the dispersion in the electrophoretic display device of the second embodiment. In FIG. 7, the counter substrate 60 is not shown.
The electrophoretic display device according to the second embodiment is different from the first embodiment in the configurations of the polymerizable surfactant and the polymerizable monomer, and the other configurations are the same as those in the first embodiment. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals and detailed description thereof is omitted.

  As shown in FIG. 7, the electrophoretic display device 200 of this embodiment has a sealing film 230 that seals the plurality of cells 13 filled with the dispersion liquid 20. The sealing film 230 is, for example, an anionic first polymerizable surfactant 31, a cationic second polymerizable surfactant 32, and a polymer film, which are sequentially arranged so as to cover the dispersion 20 and the partition wall 12. 38. The polymer film 38 is obtained by polymerizing a hydrophobic monomer 35 as a polymerizable monomer and an ionic hydrophilic monomer 37. That is, the ionic hydrophilic monomer 37 is applied instead of the third polymerizable surfactant 33 in the first embodiment.

The ionic hydrophilic monomer 37 has at least a charged group (in this case, an anionic group) and a polymerizable group in its structure. Preferred examples of the anionic group include those selected from the group of sulfonic acid groups, sulfinic acid groups, carboxyl groups, carbonyl groups, and salts thereof.
The polymerizable group is an unsaturated hydrocarbon group capable of radical polymerization, and is preferably selected from the group consisting of a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, a propenyl group, a vinylidene group, and a vinylene group. .

  Examples of ionic hydrophilic monomers other than the hydrophilic monomer 37 having an anionic group include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, etc. having an OH group, and ethyldiethylene glycol having an ethylene oxide group. Acrylate, polyethylene glycol monomethacrylate, methoxypolyethylene glycol methacrylate, etc., acrylamide having an amide group, N, N-dimethylacrylamide, etc., N-methylaminoethyl methacrylate containing amino group, N-methylaminoethyl acrylate, dimethylaminoethyl methacrylate, Acrylamide such as dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, diethylaminoethyl methacrylate Alkylamino esters of acid or methacrylic acid; N- (2-dimethylaminoethyl) acrylamide, N- (2-dimethylaminoethyl) methacrylamide, N, N-dimethylaminopropylacrylamide, etc. Saturated amides, monovinyl pyridines such as vinyl pyridine, vinyl ethers having an alkylamino group such as dimethylaminoethyl vinyl ether; vinyl imidazole, N-vinyl-2-pyrrolidone, and the like.

As a method for manufacturing the electrophoretic display device 200 (method for forming the sealing film 230), steps S1 to S4 shown in FIG. 4 are common. In the arrangement step of the polymerizable monomer in step S5, first, after introducing the hydrophobic monomer 35 into the aqueous phase 70, the ionic hydrophilic monomer 37 is introduced. As a result, the hydrophobic monomer 35 is disposed on the cationic second polymerizable surfactant 32, and the ionic hydrophilic monomer 37 is disposed outside the hydrophobic monomer 35.
In the polymerization step of Step S7, the second polymerizable surfactant 32, the hydrophobic monomer 35, and the hydrophilic monomer 37 are polymerized to form a polymer film 38, and a sealing film 230 having a desired film thickness and characteristics is formed. .

  According to the electrophoretic display device 200 and the method for manufacturing the same, the electrophoretic display device can be driven at a low voltage and has excellent display quality with a simpler configuration and a simpler process than the first embodiment. 200 and its manufacturing method can be provided.

(Embodiment 3)
<Electronic equipment>
Next, electronic devices to which the above-described electrophoretic display device 100 or electrophoretic display device 200 is applied will be described with reference to FIGS. FIG. 8 is a perspective view illustrating a configuration of electronic paper as an example of the electronic apparatus.
As shown in FIG. 8, an electronic paper 400 as an electronic apparatus according to the present embodiment is composed of a rewritable sheet having flexibility and having the same texture and flexibility as conventional paper. A main body 402 is provided. In the main body 402, the electrophoretic display device 100 according to the first embodiment or the electrophoretic display device 200 according to the second embodiment is mounted as the display unit 401.

FIG. 9 is a perspective view illustrating a configuration of an electronic notebook as an example of an electronic device.
As shown in FIG. 9, an electronic notebook 500 as an electronic device is one in which a plurality of electronic papers 400 shown in FIG. 8 are bundled and sandwiched between covers 501. The cover 501 includes display data input means (not shown) for inputting display data sent from an external device, for example. Thereby, according to the display data, the display content can be changed or updated while the electronic paper is bundled.
Since the electronic paper 400 and the electronic notebook 500 described above include the electrophoretic display device 100 according to the first embodiment or the electrophoretic display device 200 according to the second embodiment, high-quality image display can be performed. .

  The present invention is not limited to the above-described embodiment, and various modifications and improvements can be added to the above-described embodiment without departing from the spirit or idea of the invention that can be read from the claims and the entire specification. It is. A modification will be described below.

(Modification 1) The third polymerizable surfactant 33 is not limited to an anionic or cationic polymerizable surfactant, and a nonionic polymerizable surfactant can also be used. Examples of nonionic polymerizable surfactants include the following. Polyethylene oxide addition type such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamide; polyol ester type such as glycerin alkyl ester, sorbitan alkyl ester, sugar alkyl ester; polyhydric alcohol Polyether type such as alkyl ether; alkanolamide type such as alkanolamine fatty acid amide, and more specifically, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene Alkyl allyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, poly Ethers such as oxyethylene alkyl ether and polyoxyalkylene alkyl ether, polyoxyethylene oleic acid, polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan Examples thereof include esters such as sesquioleate, polyoxyethylene monooleate, and polyoxyethylene stearate.
When a nonionic polymerizable surfactant is used as the third polymerizable surfactant 33, it can be used not only independently but also in combination with an ionic polymerizable surfactant. The sealing film 30 having desired characteristics can be formed by mixing a nonionic polymerizable surfactant and an ionic polymerizable surfactant.

(Modification 2) The polymerizable monomer constituting the polymer film 36 is not limited to the hydrophobic monomer 35. For example, by using a monomer having a large molecular weight, the polymer molecular weight to be polymerized increases and a dense film is formed. This makes it possible to improve the sealing function for preventing moisture and gas from entering.
Further, for example, by using a cross-linking agent such as a polyfunctional acrylate, the molecular weight of the polymer formed by polymerization can be increased and a more precise cross-linked structure can be formed, so that the sealing function can be improved.
Further, by using an ionic polymerizable surfactant having a large molecular weight, the film-constituting molecules are polymerized. Since the polymerization starting point is reduced, there is an advantage that the amount of the polymerization initiator can be reduced as compared with the case of using an ionic polymerizable surfactant having a low molecular weight.

(Modification 3) The sealing film 30 is not limited to be formed so as to cover the dispersion 20 and the partition wall 12. FIG. 10 is a schematic cross-sectional view showing a configuration of a modified electrophoretic display device. The same components as those of the electrophoretic display device 100 are denoted by the same reference numerals, and detailed description thereof is omitted.
For example, as shown in FIG. 10, an electrophoretic display device 300 according to a modified example includes a cell matrix 10 in which a dispersion liquid 20 containing electrophoretic particles 21 is filled in each of a plurality of cells 13, an element substrate 50, and a counter substrate 60. Each cell 13 has a sealing film 330 that covers the surface of the dispersion 20. The element substrate 50 having the pixel electrode 51 and the counter substrate 60 having the counter electrode 61 are joined with the cell matrix 10 interposed therebetween. As the sealing film 330, the configuration of the sealing film 30 in the electrophoretic display device 100 of the first embodiment can be adopted. That is, the ionic first polymerizable surfactant 31, the second polymerizable surfactant 32, the third polymerizable surfactant 33, and the second polymerizable surfactant 32 and the third polymerizable surfactant. 33 includes a polymer film 36 polymerized with 33.
In the electrophoretic display device 330 of the modification, the first polymerizable surfactant 31 does not need to have an affinity for the material constituting the partition wall 12. As a result, there is an advantage that the degree of freedom of material selection of the partition wall 12 and the first polymerizable surfactant 31 is improved.

  DESCRIPTION OF SYMBOLS 10 ... Cell matrix, 11 ... Flat plate part as a board | substrate, 12 ... Partition, 13 ... Cell, 20 ... Dispersion liquid, 21 ... Electrophoretic particle, 22 ... Dispersion medium, 30 ... Sealing film, 31 ... 1st polymeric interface Activator, 31a ... hydrophobic group, 31b ... polymerizable group, 32 ... second polymerizable surfactant, 32a ... hydrophobic group, 32b ... polymerizable group, 33 ... third polymerizable surfactant, 33a ... hydrophobic 33b ... polymerizable group, 35 ... hydrophobic monomer, 36 ... polymer film, 37 ... hydrophilic monomer, 38 ... polymer film, 100, 200, 300 ... electrophoretic display device, 230, 330 ... sealing film, 400: Electronic paper as an electronic device, 500: Electronic notebook as an electronic device.

Claims (9)

A substrate,
A partition wall dividing the region on the substrate into a plurality of cells;
A dispersion containing electrophoretic particles filled in the plurality of cells;
A sealing film for sealing the plurality of cells,
The sealing film is
An ionic first polymerizable surfactant;
An ionic second polymerizable surfactant having an opposite polarity to the first polymerizable surfactant;
A third polymerizable surfactant;
An electrophoretic display device comprising: a polymer film in which a polymerizable monomer is polymerized between the second polymerizable surfactant and the third polymerizable surfactant.   The electrophoretic display device according to claim 1, wherein the third polymerizable surfactant is an ionic polymerizable surfactant.   The electrophoretic display device according to claim 1, wherein the third polymerizable surfactant is a nonionic polymerizable surfactant. A substrate,
A partition wall dividing the region on the substrate into a plurality of cells;
A dispersion containing electrophoretic particles filled in the plurality of cells;
A sealing film for sealing the plurality of cells,
The sealing film is
An ionic first polymerizable surfactant;
An ionic second polymerizable surfactant having an opposite polarity to the first polymerizable surfactant;
An electrophoretic display device comprising: a polymer film obtained by polymerizing a hydrophobic monomer and an ionic hydrophilic monomer with respect to the second polymerizable surfactant. A method of manufacturing an electrophoretic display device comprising: partition walls that partition a plurality of cells on a substrate; and a dispersion liquid containing electrophoretic particles filled in the cells,
A first step of supplying an ionic first polymerizable surfactant to the liquid surface of the dispersion filled in the cell;
A second step of supplying an ionic second polymerizable surfactant having an opposite polarity to the first polymerizable surfactant;
A third step of supplying a polymerizable monomer;
A fourth step of supplying a third polymerizable surfactant;
And a fifth step of forming a sealing film that seals the plurality of cells by polymerizing the polymerizable monomer. In the first to fourth steps, the first polymerizable surfactant, the second polymerizable surfactant, the polymerizable monomer, and the third polymerizable surfactant are each introduced into an aqueous solution. ,
The dispersion is performed by immersing the substrate filled in the cell,
The method of manufacturing an electrophoretic display device according to claim 5, wherein the fifth step is performed by introducing a polymerization initiator into the aqueous solution. A method of manufacturing an electrophoretic display device comprising: partition walls that partition a plurality of cells on a substrate; and a dispersion liquid containing electrophoretic particles filled in the cells,
A first step of supplying an ionic first polymerizable surfactant to the liquid surface of the dispersion filled in the cell;
A second step of supplying an ionic second polymerizable surfactant having an opposite polarity to the first polymerizable surfactant;
A third step of supplying an ionic hydrophilic monomer after supplying the hydrophobic monomer;
And a fourth step of forming a sealing film for sealing the plurality of cells by polymerizing the hydrophobic monomer and the ionic hydrophilic monomer. Method. In the first to third steps, the first polymerizable surfactant, the second polymerizable surfactant, the hydrophobic monomer, and the ionic hydrophilic monomer are respectively introduced into the aqueous solution. The dispersion is performed by immersing the substrate filled in the cell,
The method of manufacturing an electrophoretic display device according to claim 7, wherein the fourth step is performed by introducing a polymerization initiator into the aqueous solution.   An electronic apparatus comprising the electrophoretic display device according to claim 1.

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