WO2016199617A1 - Display device and electronic apparatus - Google Patents

Display device and electronic apparatus Download PDF

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Publication number
WO2016199617A1
WO2016199617A1 PCT/JP2016/065974 JP2016065974W WO2016199617A1 WO 2016199617 A1 WO2016199617 A1 WO 2016199617A1 JP 2016065974 W JP2016065974 W JP 2016065974W WO 2016199617 A1 WO2016199617 A1 WO 2016199617A1
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WO
WIPO (PCT)
Prior art keywords
particles
display device
migrating particles
porous layer
display
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PCT/JP2016/065974
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French (fr)
Japanese (ja)
Inventor
亮 加瀬川
小林　健
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ソニー株式会社
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Publication of WO2016199617A1 publication Critical patent/WO2016199617A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/165—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field
    • G02F1/1675—Constructional details
    • G02F1/1677—Structural association of cells with optical devices, e.g. reflectors or illuminating devices
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/165—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field
    • G02F1/166—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field characterised by the electro-optical or magneto-optical effect
    • G02F1/167—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field characterised by the electro-optical or magneto-optical effect by electrophoresis
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
    • G09F9/37—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements being movable elements

Definitions

  • the present disclosure relates to a display device and an electronic apparatus that perform image display using an electrophoresis phenomenon.
  • an electrophoretic display device that produces a contrast (contrast) using an electrophoretic phenomenon can be cited.
  • Various studies have been made on display methods of electrophoretic display devices. Specifically, a method has been proposed in which two types of charged particles having different optical reflection characteristics and polarities are dispersed in an insulating liquid, and each charged particle is moved using the difference in polarity. In this method, since the distribution of the two types of charged particles changes according to the electric field, contrast is generated using the difference in optical reflection characteristics.
  • the display since display is performed using the contrast of reflected light as described above, the display is basically monochrome (monochrome) display.
  • a pair of opposing substrates is displayed.
  • an image display device in which a layer having a gap is provided between the two, and two types of migrating particles having different colors and particle sizes are used.
  • the gap of the layer disposed between the pair of substrates is large enough to prevent one of the two types of migrating particles from entering, thereby enabling multicolor display.
  • a display device includes a plurality of types of migrating particles having different average particle sizes, and a plurality of porous layers that are formed of a fibrous structure and have different average pore sizes. is there.
  • An electronic apparatus includes the display device according to the embodiment of the present disclosure.
  • a plurality of types of migrating particles having different average particle diameters and a plurality of porous particles having a different average pore diameter from each other are formed by a fibrous structure.
  • the moving distance of the migrating particles is adjusted by the particle size of the migrating particles and the pore size of the porous layer.
  • migration is performed by using a plurality of types of migrating particles having different average particle sizes and a plurality of porous layers having different average pore sizes.
  • the moving distance of the particles was adjusted by the particle size of the migrating particles and the pore size of the porous layer.
  • the time required for display switching can be shortened. Therefore, it is possible to provide a display device and an electronic device that can perform multicolor display while improving display quality. Note that the effects described here are not necessarily limited, and may be any effects described in the present disclosure.
  • FIG. 2 is a schematic diagram for explaining the operation of the electrophoretic element shown in FIG. 1.
  • FIG. 2 is a schematic diagram for explaining the operation of the electrophoretic element shown in FIG. 1.
  • It is a conceptual diagram explaining the cyan display in the display apparatus shown in FIG. It is a characteristic view explaining the waveform of the applied voltage at the time of the cyan display shown to FIG. 5A. It is a conceptual diagram explaining the magenta display in the display apparatus shown in FIG. FIG.
  • 6B is a characteristic diagram illustrating a waveform of an applied voltage during magenta display illustrated in FIG. 6A. It is a conceptual diagram explaining the yellow display in the display apparatus shown in FIG. It is a characteristic view explaining the waveform of the applied voltage at the time of yellow display shown to FIG. 7A. It is a conceptual diagram explaining the yellow display in the display apparatus as a comparative example. It is a characteristic view explaining the waveform of the applied voltage at the time of yellow display shown to FIG. 8A. 14 is a cross-sectional view illustrating a configuration of a display device according to Modification 1 of the present disclosure. It is a schematic diagram explaining the white display in the display apparatus shown in FIG. It is a schematic diagram explaining the black display in the display apparatus shown in FIG.
  • FIG. 14 It is a schematic diagram explaining the red display in the display apparatus shown in FIG. 14 is a cross-sectional view illustrating a configuration of a display device according to Modification 2 of the present disclosure.
  • FIG. It is a figure showing the time change of the electric potential difference with respect to the display surface side of the back side of the display apparatus shown in FIG. It is a figure showing the time change of the average distribution position of each migrating particle by the time change of the electric potential difference shown in FIG. It is a figure showing the time change of the electric potential difference with respect to the display surface side of the back side of a general display apparatus. It is a figure showing the time change of the average distribution position of each migrating particle by the time change of the electric potential difference shown in FIG.
  • FIG. 16B is a perspective view illustrating another example of the electronic book illustrated in FIG. 16A. It is a perspective view showing the external appearance of the tablet personal computer using the display apparatus of this indication.
  • Embodiment display device having electrophoretic particles having a plurality of types of particle sizes and a porous layer having a plurality of types of pore sizes
  • Configuration of electrophoretic element 1-2.
  • Action / Effect Modification 1 Display device having a plurality of types of migrating particles and a plurality of types of porous layers each having a different charge amount
  • Configuration of electrophoretic element 2-2.
  • Modification 2 Display device in which a plurality of porous layers having light transmittance on the display surface side and different pore diameters are laminated
  • Action / effect 4 Application example (electronic equipment)
  • FIG. 1 illustrates a cross-sectional configuration of a display device (display device 1) according to an embodiment of the present disclosure.
  • FIG. 2 shows a planar configuration of the electrophoretic element 30 constituting the display device 1.
  • the display device 1 is applied to various electronic devices such as a display device that displays an image by using an electrophoretic phenomenon and displays an image, for example, an electronic paper display.
  • the display device 1 includes, for example, a display layer including an electrophoretic element 30 between a drive substrate 10 and a counter substrate 20 that are disposed to face each other with a spacer 35 interposed therebetween.
  • the electrophoretic element 30 includes an insulating liquid 31 including electrophoretic particles 32 and a porous layer 33 having a plurality of pores 333.
  • the porous layer 33 has a fibrous structure 331 and non-migrating particles 332 held by the fibrous structure 331.
  • 1 and 2 schematically show the configuration of the electrophoretic element 30 and may differ from actual dimensions and shapes.
  • the migrating particles 32 have a plurality of types of average particle sizes
  • the porous layer 33 has a configuration in which layers having a plurality of types of average pore sizes are stacked.
  • the insulating liquid 31 is, for example, one type or two or more types of non-aqueous solvents such as an organic solvent, and specifically includes paraffin or isoparaffin. It is preferable that the viscosity and refractive index of the insulating liquid 31 be as low as possible. This is because the mobility (response speed) of the migrating particles 32 is improved, and the energy (power consumption) required to move the migrating particles 32 is lowered accordingly. Further, the difference between the refractive index of the insulating liquid 31 and the refractive index of the porous layer 33 is increased, and the light reflectance of the porous layer 33 is increased. Note that a weak conductive liquid may be used instead of the insulating liquid 31.
  • the insulating liquid 31 may contain various materials as necessary. This material is, for example, a colorant, a charge control agent, a dispersion stabilizer, a viscosity modifier, a surfactant or a resin.
  • the electrophoretic particles 32 are one or more charged particles that are electrically movable, and are dispersed in the insulating liquid 31.
  • the migrating particles 32 in the present embodiment have a plurality of types of average particle diameters, and are composed of one or more charged particles for each average particle diameter.
  • the migrating particles 32 have the same number of types of average particle diameter as the number of porous layers 33 to be described later.
  • four types of migrating particles 32A and 32B having different average particle diameters are used. , 32C, 32D.
  • the migrating particles 32 also have arbitrary optical reflection characteristics (light reflectivity).
  • the light reflectance of the migrating particles 32 is not particularly limited, but is preferably set so that at least the migrating particles 32 can shield the porous layer 33. This is because contrast is generated by utilizing the difference between the light reflectance of the migrating particles 32 and the light reflectance of the porous layer 33.
  • the four types of migrating particles 32A, 32B, 32C, and 32D constituting the migrating particle 32 have different colors for each average particle diameter. Specifically, for example, it is colored cyan (electrophoretic particles 32A), magenta (electrophoretic particles 32B), yellow (electrophoretic particles 32C), and black (electrophoretic particles 32D).
  • the particle size of the migrating particles 32 is preferably in the range of, for example, 100 nm or more and 2 ⁇ m or less, and the average particle size of the migrating particles 32A, 32B, 32C, and 32D is, for example, 1.2 ⁇ m (electrophoretic particle 32A), 1 ⁇ m (electrophoretic particle 32B), 0.8 ⁇ m (electrophoretic particle 32C), and 0.6 ⁇ m (electrophoretic particle 32D).
  • the average particle size of each migrating particle 32A, 32B, 32C, 32D is not limited to the above value.
  • the smaller migrating particle has an average particle size a 1 and a particle size dispersion value ⁇ 1 and a larger side. If the electrophoretic particles and the average particle diameter a 2 and a particle size distribution value sigma 2, may be a relationship between a 1 -2 ⁇ 1> a 2 + 2 ⁇ 2.
  • the migrating particles 32 (32A, 32B, 32C, 32D) can move between the pixel electrode 14 and the counter electrode 22 in the insulating liquid 31.
  • the migrating particles 32 are, for example, one kind or two or more kinds of particles (powder) such as an organic pigment, an inorganic pigment, a dye, a carbon material, a metal material, a metal oxide, glass, or a polymer material (resin). .
  • the migrating particles 32 may be pulverized particles or capsule particles of resin solids containing the above-described particles. However, materials corresponding to carbon materials, metal materials, metal oxides, glass, or polymer materials are excluded from materials corresponding to organic pigments, inorganic pigments, or dyes.
  • Organic pigments include, for example, azo pigments, metal complex azo pigments, polycondensed azo pigments, flavanthrone pigments, benzimidazolone pigments, phthalocyanine pigments, quinacridone pigments, anthraquinone pigments, perylene pigments, perinones. Pigments, anthrapyridine pigments, pyranthrone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments or indanthrene pigments.
  • Inorganic pigments include, for example, zinc white, antimony white, carbon black, iron black, titanium boride, bengara, mapico yellow, red lead, cadmium yellow, zinc sulfide, lithopone, barium sulfide, cadmium selenide, calcium carbonate, barium sulfate, Lead chromate, lead sulfate, barium carbonate, lead white or alumina white.
  • the dye include nigrosine dyes, azo dyes, phthalocyanine dyes, quinophthalone dyes, anthraquinone dyes, and methine dyes.
  • the carbon material is, for example, carbon black.
  • the metal material is, for example, gold, silver or copper.
  • metal oxides include titanium oxide, zinc oxide, zirconium oxide, barium titanate, potassium titanate, copper-chromium oxide, copper-manganese oxide, copper-iron-manganese oxide, and copper-chromium-manganese oxide. Or copper-iron-chromium oxide.
  • the polymer material is, for example, a polymer compound in which a functional group having a light absorption region in the visible light region is introduced. As long as the polymer compound has a light absorption region in the visible light region, the type of the compound is not particularly limited.
  • Specific materials for forming the migrating particles 32 are selected according to, for example, the role that the migrating particles 32 play in order to cause contrast.
  • the material in which white display is performed by the migrating particles 32 is, for example, a metal oxide such as titanium oxide, zinc oxide, zirconium oxide, barium titanate or potassium titanate, and among these, titanium oxide is preferable. This is because it is excellent in electrochemical stability and dispersibility and has high reflectance.
  • the material in the case where black display is performed by the migrating particles 32 is, for example, a carbon material or a metal oxide.
  • the carbon material is, for example, carbon black
  • the metal oxide is, for example, copper-chromium oxide, copper-manganese oxide, copper-iron-manganese oxide, copper-chromium-manganese oxide, or copper-iron. -Chromium oxide and the like.
  • a carbon material is preferable. This is because excellent chemical stability, mobility and light absorption are obtained.
  • the migrating particles 32A, 32B, 32C, and 32D exhibit cyan, magenta, yellow, and black, respectively.
  • the electrophoretic particles 32D exhibiting black are formed of the carbon material or the metal oxide.
  • the migrating particles 32A exhibiting a cyan color, the migrating particles 32B exhibiting a magenta color, and the migrating particles 32C exhibiting a yellow color can be formed using pigments exhibiting corresponding colors.
  • Specific materials include, for example, quinacridone, perylene, perinone, isoindolinone, dioxazine, isoindoline, anthraquinone, quinophthalone, diketopyrrolopyrrole, and other polycyclic pigments, phthalocyanine pigments, azo lake red, azo lake red, piazolone, Examples thereof include azo pigments such as disazo, monoazo, condensed azo, naphthol, and pendimidazolone, and inorganic pigments such as cadmium yellow, strontium chromate, viridian, oxide chromium, cobalt blue, and ultramarine.
  • the content (concentration) of the migrating particles 32 (32A, 32B, 32C, and 32D) in the insulating liquid 31 is not particularly limited, but the entire migrating particles 32 are, for example, 0.1 wt% to 10 wt%. It is preferable. This is because the shielding property of the porous layer 33 by the migrating particles 32 and the concealing property and mobility of the migrating particles 32 by the porous layer 33 are ensured. If the amount is less than 0.1% by weight, the migrating particles 32 may hardly shield the porous layer 33. On the other hand, when the amount is more than 10% by weight, the dispersibility of the migrating particles 32 is lowered, so that the migrating particles 32 are difficult to migrate and may be aggregated in some cases.
  • the electrophoretic particles 32A, 32B, 32C, and 32D colored in the respective colors may be, for example, 0.1% by weight to 4% by weight for the electrophoretic particle 32A having the largest particle size, and the next largest electrophoretic particle For particles 32B, 0.1% to 4% by weight, for the next larger migrating particles 32C, 0.1% to 4% by weight, and for the smallest migrating particles 32D, 0.1% to 4% by weight.
  • the migrating particles 32 are easily dispersed and charged in the insulating liquid 31 for a long period of time and are not easily adsorbed by the porous layer 33.
  • a dispersant or a charge adjusting agent
  • the electrophoretic particles 32 may be subjected to a surface treatment, or both may be used in combination.
  • the dispersing agent is, for example, Solsperse series manufactured by Lubrizol, BYK® series or Anti-Terra® series manufactured by BYK-Chemie, or Span series manufactured by ICI® Americas®.
  • the surface treatment is, for example, rosin treatment, surfactant treatment, pigment derivative treatment, coupling agent treatment, graft polymerization treatment or microencapsulation treatment.
  • graft polymerization treatment, microencapsulation treatment, or a combination thereof is preferable. This is because long-term dispersion stability and the like can be obtained.
  • the surface treatment material is, for example, a material (adsorbing material) having a functional group and a polymerizable functional group that can be adsorbed on the surface of the migrating particle 32.
  • the type of functional group that can be adsorbed is determined according to the material for forming the migrating particles 32.
  • carbon materials such as carbon black are aniline derivatives such as 4-vinylaniline, and metal oxides are organosilane derivatives such as 3- (trimethoxysilyl) propyl methacrylate.
  • the polymerizable functional group include a vinyl group, an acrylic group, and a methacryl group.
  • the material for surface treatment is, for example, a material (graftable material) that can be grafted on the surface of the migrating particles 32 into which a polymerizable functional group is introduced.
  • the graft material preferably has a polymerizable functional group and a dispersing functional group that can be dispersed in the insulating liquid 31 and can maintain dispersibility due to steric hindrance.
  • the kind of polymerizable functional group is the same as that described for the adsorptive material.
  • the dispersing functional group is, for example, a branched alkyl group when the insulating liquid 31 is paraffin.
  • a polymerization initiator such as azobisisobutyronitrile (AIBN) may be used.
  • the porous layer 33 is, for example, a three-dimensional structure (irregular network structure such as a nonwoven fabric) formed by a fibrous structure 331 as shown in FIG.
  • the porous layer 33 has a plurality of gaps (pores 333) through which the migrating particles 32 pass in places where the fibrous structure 331 does not exist.
  • FIG. 1 the illustration of the porous layer 33 is simplified.
  • the fibrous structure 331 is a fibrous substance having a sufficiently large length with respect to the fiber diameter (diameter).
  • the shape (external appearance) of the fibrous structure 331 is not particularly limited as long as the fibrous structure 331 has a fibrous shape that is sufficiently long with respect to the fiber diameter as described above. Specifically, it may be linear, may be curled, or may be bent in the middle. Moreover, you may branch to 1 or 2 or more directions on the way, not only extending in one direction.
  • the formation method of the fibrous structure 331 is not particularly limited.
  • phase separation method for example, a phase separation method, a phase inversion method, an electrostatic (electric field) spinning method, a melt spinning method, a wet spinning method, a dry spinning method, a gel spinning method, A sol-gel method or a spray coating method is preferred.
  • a fibrous material having a sufficiently large length with respect to the fiber diameter can be easily and stably formed.
  • the average fiber diameter of the fibrous structure 331 is not particularly limited, but is preferably as small as possible. This is because light easily diffuses and the average pore diameter of the pores 333 increases. However, the average fiber diameter is preferably determined so that the fibrous structure 331 can hold the non-migrating particles 332. For this reason, it is preferable that the average fiber diameter of the fibrous structure 331 is 10 micrometers or less. In addition, although the minimum of an average fiber diameter is not specifically limited, For example, it is 0.1 micrometer and may be less than that. This average fiber diameter is measured, for example, by microscopic observation using a scanning electron microscope (SEM) or the like. Note that the average length of the fibrous structure 331 may be arbitrary.
  • SEM scanning electron microscope
  • the fibrous structure 331 includes one or more non-migrating particles 332, and the non-migrating particles 332 are held by the fibrous structure 331.
  • the porous layer 33 which is a three-dimensional structure, one fibrous structure 331 may be entangled at random, or a plurality of fibrous structures 331 may be gathered and overlap at random. However, both may be mixed.
  • each fibrous structure 331 preferably holds one or more non-migrating particles 332.
  • FIG. 2 shows a case where the porous layer 33 is formed by a plurality of fibrous structures 331.
  • the porous layer 33 is a three-dimensional structure
  • the irregular three-dimensional structure easily causes external light to be irregularly reflected (multiple scattering), so that the light reflectance of the porous layer 33 increases and the high light
  • the porous layer 33 can be thin in order to obtain the reflectance.
  • the contrast increases and the energy required to move the migrating particles 32 decreases.
  • the migrating particles 32 can easily pass through the pores 333. As a result, the time required to move the migrating particles 32 is shortened, and the energy required to move the migrating particles 32 is also reduced.
  • non-migrating particles 332 are included in the fibrous structure 331 .
  • the non-migrating particles 332 are likely to cause irregular reflection of external light, and the light reflectance of the porous layer 33 becomes higher. Thereby, contrast becomes higher.
  • the porous layer 33 is constituted by a plurality of layers having different average pore diameters of the pores 333 as described above.
  • the porous layer 33 has a multilayer structure in which the same number of types of the average particle diameters of the migrating particles 32, that is, the same number of colors as the migrating particles 32 are laminated. Then, it has a configuration in which four types of layers (porous layers 33A, 33B, 33C, 33D) having different average pore diameters are laminated. These four types of porous layers 33A, 33B, 33C, and 33D are laminated so that the average pore diameter decreases from the display surface S1 side to the back surface S2 side.
  • the pore diameter of the porous layer 33 is not particularly limited, but is generally preferably as large as possible. This is because the migrating particles 32 easily pass through the pores 333.
  • the pore diameters of the porous layers 33A, 33B, 33C, and 33D are determined by the particle diameters of the migrating particles 32A, 32B, 32C, and 32D described above.
  • the porous layer 33A preferably has a pore diameter through which all the migrating particles 32A, 32B, 32C, and 32D can pass, and the average pore diameter is, for example, It is preferably in the range of 100 nm to 5 ⁇ m.
  • the porous layer 33B preferably has a pore diameter through which the migrating particles 32B, 32C, and 32D other than the migrating particle 32A can pass, and the average pore diameter is preferably in the range of, for example, 1.11 ⁇ m to 1.3 ⁇ m.
  • the porous layer 33C preferably has a pore diameter through which the migrating particles 32C and 32D other than the migrating particles 32A and 32B can pass, and the average pore diameter is preferably in the range of 0.91 ⁇ m to 1.1 ⁇ m, for example. .
  • the porous layer 33D has only to have a pore size through which only the migrating particles 32D can pass, and the pore size is preferably in the range of 0.71 ⁇ m to 0.9 ⁇ m, for example. Thereby, the moving distance between the driving substrate 10 and the counter substrate 20 of the migrating particles 32A, 32B, 32C, and 32D is controlled.
  • the thickness of the porous layers 33A, 33B, 33C, and 33D is not particularly limited.
  • the entire porous layer 33 is preferably 5 ⁇ m to 100 ⁇ m. This is because the concealability of the porous layer 33 is enhanced, and the migrating particles 32 can easily pass through the pores 333.
  • at least the thickness of the porous layer 33A disposed on the display surface side is at least a thickness capable of concealing the electrophoretic particles 32A when the electrophoretic particles 32A having the largest pore diameter move to the back surface S2. Is preferred.
  • the porous layers 33A, 33B, 33C, and 33D may have the same thickness as long as they are within the above range, but considering the time required for display switching, the migrating particles 32A, 32B, and 32C The moving distance of 32D is preferably shorter.
  • the thicknesses of the porous layers 33A, 33B, 33C, and 33D are preferably set in the following ranges, respectively.
  • the thickness of the porous layer 33A is preferably, for example, 10 ⁇ m or more and 30 ⁇ m or less
  • the thickness of the porous layer 33B is, for example, preferably 2 ⁇ m or more and 15 ⁇ m or less
  • the thickness of the porous layer 33C is, for example,
  • the thickness is preferably 2 ⁇ m or more and 15 ⁇ m or less
  • the thickness of the porous layer 33D is preferably, for example, 2 ⁇ m or more and 15 ⁇ m or less.
  • the fibrous structure 331 is formed including any one type or two or more types of polymer materials such as acrylic resins or inorganic materials, for example, and may include other materials.
  • the polymer material include nylon, polylactic acid, polyamide, polyimide, polyethylene terephthalate, polyacrylonitrile, polyethylene oxide, polyvinyl carbazole, polyvinyl chloride, polyurethane, polystyrene, polyvinyl alcohol, polysulfone, polyvinyl pyrrolidone, polyvinylidene fluoride, poly Examples thereof include hexafluoropropylene, cellulose acetate, collagen, gelatin, chitosan, and copolymers thereof.
  • the inorganic material include titanium oxide.
  • a polymer material is preferable as a material for forming the fibrous structure 331. This is because the reactivity (photoreactivity, etc.) is low, that is, because it is chemically stable, the unintended decomposition reaction of the fibrous structure 331 is suppressed. Note that in the case where the fibrous structure 331 is formed of a highly reactive material, the surface of the fibrous structure 331 is preferably covered with an arbitrary protective layer.
  • the fibrous structure 331 is preferably a nanofiber. Since the three-dimensional structure is complicated and it becomes easy to diffusely reflect external light, the light reflectance of the porous layer 33 is further increased, and the volume ratio of the pores 333 in the unit volume of the porous layer 33 is increased. This is because the migrating particles 32 can easily pass through the pores 333. Thereby, the contrast becomes higher and the energy required to move the migrating particles 32 becomes lower.
  • Nanofiber is a fibrous substance having a fiber diameter of 0.001 ⁇ m to 0.1 ⁇ m and a length that is 100 times or more of the fiber diameter.
  • the fibrous structure 331 that is a nanofiber is preferably formed by an electrospinning method using a polymer material. This is because the fibrous structure 331 having a small fiber diameter can be easily and stably formed.
  • the fibrous structure 331 has an optical reflection characteristic different from that of the migrating particles 32A, 32B, 32C, and 32D.
  • the light reflectance of the fibrous structure 331 is not particularly limited, but is preferably set so that at least the porous layer 33 can shield the migrating particles 32 as a whole. This is because the contrast is generated by utilizing the difference between the light reflectance of the migrating particles 32 and the light reflectance of the porous layer 33 as described above. Accordingly, the fibrous structure 331 having light transparency (colorless and transparent) in the insulating liquid 31 is not preferable.
  • the light reflectivity of the fibrous structure 331 hardly affects the light reflectivity of the entire porous layer 33, and the light reflectivity of the entire porous layer 33 is substantially the light reflectivity of the non-migrating particles 332.
  • the light reflectance of the fibrous structure 331 may be arbitrary.
  • Non-electrophoretic particles 332 are particles that are fixed to the fibrous structure 331 and do not migrate electrically.
  • the material for forming the non-electrophoretic particles 332 is, for example, the same as the material for forming the electrophoretic particles 32, and is selected according to the role played by the non-electrophoretic particles 332 as described later.
  • the non-migrating particle 332 may be partially exposed from the fibrous structure 331 or embedded therein.
  • the non-migrating particles 332 have optical reflection characteristics different from those of the migrating particles 32A, 32B, 32C, and 32D.
  • the light reflectance of the non-migrating particles 332 is not particularly limited, but is preferably set so that at least the porous layer 33 can shield the migrating particles 32 as a whole. This is because the contrast is displayed using the difference between the light reflectance of the migrating particles 32 and the light reflectance of the porous layer 33 as described above.
  • the specific forming material of the non-migrating particles 332 is selected according to the role played by the non-migrating particles 332 in order to generate contrast, for example.
  • the non-migrating particles 332 are preferably responsible for white display, for example. .
  • a metal oxide is preferable and titanium oxide is more preferable. This is because it is excellent in electrochemical stability and fixability, and high reflectance can be obtained.
  • the material for forming the non-migrating particles 332 may be the same material as the material for forming the migrating particles 32 or may be a different material.
  • the spacer 35 includes, for example, an insulating material such as a polymer material.
  • an insulating material such as a polymer material.
  • the configuration of the spacer 35 is not particularly limited, and may be a sealing material mixed with fine particles.
  • the shape of the spacer 35 is not particularly limited, but is preferably a shape that does not hinder the movement of the migrating particles 32 between the pixel electrode 14 and the counter electrode 22 and that can be uniformly distributed. is there. Further, the thickness of the spacer 35 (for example, the stacking direction of the porous layers 33A, 33B, 33C, and 33D) is not particularly limited, but in particular, it is preferably as thin as possible in order to reduce power consumption. 100 ⁇ m. In addition, in FIG. 1, the structure of the spacer 35 is simplified and shown.
  • the display device 1 includes a pair of substrates, the drive substrate 10 and the counter substrate 20 that are opposed to each other with the spacer 35 interposed therebetween, and includes a display layer therebetween.
  • the driving substrate 10 is, for example, one in which a thin film transistor (TFT) 12, a protective layer 13, and a pixel electrode 14 are laminated in this order on one surface of a support member 11.
  • TFT thin film transistor
  • the TFT 12 and the pixel electrode 14 are divided and formed in a matrix according to the pixel arrangement, for example, in order to construct an active matrix drive circuit.
  • the support member 11 is formed of, for example, one or more of inorganic materials, metal materials, plastic materials, and the like.
  • inorganic material include silicon (Si), silicon oxide (SiO x ), silicon nitride (SiN x ), and aluminum oxide (AlO x ).
  • Silicon oxide includes, for example, glass or spin-on-glass (SOG).
  • metal material include aluminum (Al), nickel (Ni), and stainless steel.
  • plastic material examples include polycarbonate (PC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethyl ether ketone (PEEK), cycloolefin polymer (COP), polyimide (PI), and polyether sulfone (PES). ) And the like.
  • the support member 11 may be light transmissive or non-light transmissive.
  • the support member 11 may be a rigid substrate such as a wafer, or may be a flexible thin glass or film. However, since a flexible (foldable) electronic paper display can be realized, it is desirable to be made of a flexible material.
  • the TFT 12 is a switching element for selecting a pixel.
  • the TFT 12 may be, for example, an inorganic TFT using an inorganic semiconductor layer such as amorphous silicon, polysilicon, or oxide as a channel layer (active layer), or an organic TFT using an organic semiconductor layer such as pentacene.
  • the TFT 12 is covered with, for example, a protective layer 13.
  • a flattening insulating film (not shown) made of an insulating material such as polyimide may be further provided on the protective layer 13.
  • the pixel electrode 14 is formed independently for each pixel, and includes, for example, one or more of conductive materials such as gold (Au), silver (Ag), and copper (Cu). Has been.
  • the pixel electrode 14 is electrically connected to the TFT 12. Note that the number of TFTs 12 arranged for one pixel electrode 14 is arbitrary, and is not limited to one, and may be two or more.
  • the adhesive layer 15 is bonded to the drive substrate 10 and a display layer described later, and is made of, for example, an acrylic resin, a urethane resin, or rubber, and has a thickness of, for example, 1 ⁇ m to 100 ⁇ m.
  • an anionic additive, a cationic additive, or a lithium salt additive may be added to the adhesive layer 15 for the purpose of providing conductivity.
  • the counter substrate 20 is provided with a counter electrode 22 on one surface side (display layer side) of the support member 21.
  • a color filter, an adhesive layer, and the like may be laminated.
  • the support member 21 is made of the same material as the support member 11 except that it is light transmissive. This is because the image is displayed on the upper surface side of the counter substrate 20, and thus the support member 21 needs to be light transmissive.
  • the thickness of the support member 21 is, for example, 1 ⁇ m to 250 ⁇ m.
  • the counter electrode 22 is formed including, for example, any one type or two or more types of conductive materials (transparent conductive materials) having optical transparency. Examples of such a conductive material include indium oxide-tin oxide (ITO), antimony oxide-tin oxide (ATO), fluorine-doped tin oxide (FTO), and aluminum-doped zinc oxide (AZO).
  • ITO indium oxide-tin oxide
  • ATO antimony oxide-tin oxide
  • FTO fluorine-doped tin oxide
  • AZO aluminum-doped zinc oxide
  • the thickness of the counter electrode 22 is, for example, 0.001 ⁇ m to 1 ⁇ m.
  • the counter electrode 22 is formed on the entire surface of the support member 21, for example. However, like the pixel electrode 14, the counter electrode 22 may be formed separately for each pixel, for example.
  • the light transmittance of the counter electrode 22 is preferably as high as possible, for example, 80% or more. is there.
  • the electric resistance of the counter electrode 22 is preferably as low as possible, for example, 100 ⁇ / ⁇ (square) or less.
  • an electrophoretic element 30 that is voltage-controlled for each pixel.
  • the electrophoretic element 30 generates contrast using an electrophoretic phenomenon, and includes electrophoretic particles 32 that can move between the pixel electrode 14 and the counter electrode 22 in accordance with an electric field.
  • the electrophoretic element 30 includes the porous layer 33 together with the electrophoretic particles 32 in the insulating liquid 31.
  • the insulating liquid 31 and the porous layer 33 are common to each pixel. Is provided.
  • the display device 1 is manufactured as follows, for example. First, the counter electrode 22 is provided on one surface of the support member 21 using an existing method such as various film forming methods, and the counter substrate 20 is formed. Next, a spacer 35 is formed on the counter electrode 22.
  • the spacer 35 can be formed by, for example, the following imprint method. First, a solution containing a constituent material (for example, a photosensitive resin material) of the spacer 35 is applied onto the counter electrode 22. Next, a mold having a recess on the coated surface is pressed and exposed to light, and then the mold is removed. Thereby, the columnar spacer 35 is formed.
  • the porous layer 33 is disposed between the adjacent spacers 35, that is, in the cells 34.
  • the porous layer 33 is formed through the following steps. First, a spinning solution is prepared by dispersing or dissolving a material for forming the fibrous structure 331 (for example, a polymer material) in an organic solvent or the like. Subsequently, after adding the non-migrating particles 332 to the spinning solution, the non-migrating particles 332 are dispersed in the spinning solution by sufficiently stirring. Next, using this spinning solution, for example, spinning is performed by an electrostatic spinning method. Thereby, the porous layer 33 in which the non-migrating particles 332 are held by the fibrous structure 331 is formed.
  • a spinning solution is prepared by dispersing or dissolving a material for forming the fibrous structure 331 (for example, a polymer material) in an organic solvent or the like.
  • the non-migrating particles 332 are dispersed in the spinning solution by sufficiently stirring.
  • spinning solution for example,
  • the pore diameter of the porous layer 33 is controlled by controlling the viscosity of the spinning solution, the particle diameter of the non-electrophoretic particles 332, and the scanning speed during electrostatic spinning.
  • the thickness compression amount of the porous layer 33A is 0% to 10%
  • the porous layer 33B is 10% to 20%
  • the porous layer 33C is 20% to 30%
  • the porous layer 33D is 30% to 40%.
  • the porous layer 33A, 33B, 33C, 33D having the above average pore diameter range is formed by compressing the porous membrane using the% condition.
  • the fibrous structure 331 is formed by a phase separation method, a phase inversion method, a melt spinning method, a wet spinning method, a dry spinning method, a gel spinning method, a sol-gel method, a spray coating method, or the like instead of the electrostatic spinning method. May be.
  • the insulating liquid 31 in which the migrating particles 32A, 32B, 32C, and 32D are dispersed to the counter substrate 20 on which the porous layer 33 is disposed this is treated with, for example, a sealing agent (not shown).
  • a peeling member (not shown) provided with the seal layer 16 is opposed.
  • the driving substrate 10 on which the TFT 12 and the pixel electrode 14 and the like are formed on the seal layer 16 via the adhesive layer 15 is fixed.
  • the display device 1 is completed through the above steps.
  • contrast is generated by utilizing the difference between the light reflectance of the electrophoretic particles 32 and the light reflectance of the porous layer 33.
  • FIG. 3A and 3B are schematic diagrams for explaining a basic display operation of the electrophoretic element 30.
  • FIG. Here, for the sake of clarity, the porous layer 33 is shown as a single layer, and the region in which the migrating particles 32 are disposed between the porous layer 33 and the drive substrate 10 and the counter substrate 20 (standby region R1). And the display region R2). Further, the migrating particle 32D having the smallest particle size will be described as an example.
  • the migrating particles 32D are arranged in the standby region R1 (FIG. 3A). In this case, since the migrating particles 32D are concealed by the porous layer 33 in all the pixels, no contrast is generated when the electrophoretic element 30 is viewed from the counter substrate 20 side (an image is not displayed). Is in a state.
  • the migrating particles 32D are transferred from the standby region R1 to the porous layer 33 for each pixel. It moves to the display region R2 via the pore 333.
  • the migrating particles 32 are both concealed by the porous layer 33 and non-hidden, the contrast is generated when the electrophoretic element 30 is viewed from the counter substrate 20 side. become. Thereby, an image is displayed.
  • the drive substrate 10 is provided with a peripheral circuit (not shown) for driving the electrophoretic element 30 for each pixel (applying a drive voltage between the pixel electrode 14 and the counter electrode 22).
  • the peripheral circuit includes, for example, a voltage control driver for forming an active matrix driving circuit, a power source, a memory, and the like, and corresponds to an image signal for one or more selective sub-pixels. A drive voltage can be applied.
  • the electrophoretic element 30 has a plurality of types of average particle diameters in the insulating liquid 31, and the electrophoretic particles 32A, 32B, 32C, which are color-coded according to the average particle diameter.
  • 32D and porous layers 33A, 33B, 33C, and 33D having pores 333 having different average pore diameters.
  • FIG. 4 is a schematic diagram for explaining the operation of the display device 1.
  • the porous layer 33 has a larger average pore diameter from the display surface S1 side, here, the porous layer 33A, the porous layer 33B, and the porous layer 33C from the display surface S1 side. And the porous layer 33D in this order.
  • the average pore diameter of the porous layers 33A, 33B, 33C, and 33D is determined by the migrating particles 32A, 32B, 32C, and 32D.
  • the pore size of the porous layer 33A is such that all the migrating particles 32A, 32B, 32C, and 32D can pass, and the pore size of the porous layer 33B cannot pass the migrating particle 32A, but the migrating particles 32B, 32C,
  • the porous layer 33C cannot pass through the migrating particles 32A and 32B, but the porous layer 33C can pass through the migrating particles 32A, 32B, and 32C.
  • the migrating particles 32A, 32B, 32C, and 32D can be kept at different positions.
  • FIGS. 5A to 7B are conceptual diagrams (FIGS. 5A, 6A, and 7A) showing movement of the migrating particles 32A, 32B, 32C, and 32D for explaining the display operation of the display device 1, and waveforms of applied voltages (FIG. 5B). 6B and FIG. 7B).
  • the electrophoretic particles 32A, 32B, 32C, and 32D are colored cyan (electrophoretic particles 32A), magenta (electrophoretic particles 32B), yellow (electrophoretic particles 32C), and black (electrophoretic particles 32D), respectively. .
  • the movement of the migrating particles 32A, 32B, 32C, and 32D and the waveform of the applied voltage when performing cyan display, magenta display, and yellow display will be described in this order.
  • the electrophoretic element 30 of the present embodiment in the initial state (a state in which no voltage is applied between the pixel electrode 14 and the counter electrode 22), the electrophoretic particles 32A, 32B, 32C, and 32D are on standby. It is localized in the region R1. Specifically, the migrating particles 32A, 32B, 32C, and 32D are respectively disposed on the back surface S2 side of the porous layers 33A, 33B, 33C, and 33D that can pass (time 0 in FIG. 5A). At this time, the display color is the color of the porous layer 33, that is, white.
  • the migrating particles 32A, 32B, 32C, and 32D move to the display surface S1 side.
  • FIG. 5B when a positive voltage is applied for a certain time (specifically, until the migrating particles 32A reach the display surface S1) and then stopped, as shown in FIG.
  • the particles 32A are arranged on the outermost surface of the porous layer 33, and the migrating particles 32B, 32C, and 32D are arranged in the porous layer 33. That is, the display color of the pixel including the electrophoretic element 30 is cyan.
  • the magenta display will be described.
  • the migrating particles 32B colored in magenta are arranged on the display surface S1 side.
  • 32C and 32D are arranged in the porous layer 33.
  • the electrophoretic particles 32A are positioned on the back surface S2 side in the initial state.
  • the migrating particles 32B move to the display surface S1.
  • the migrating particles 32A having a larger moving speed than the migrating particles 32B move to the back surface S2 side before the migrating particles 32B.
  • the migrating particles 32B are arranged on the outermost surface of the porous layer 33, and the migrating particles 32A and the other migrating particles 32C and 32D are arranged in the porous layer 33. That is, the display color of the pixel provided with the electrophoretic element 30 is magenta.
  • electrophoretic particles 32C colored yellow are disposed on the display surface S1 side.
  • the migrating particles 32 ⁇ / b> A, 32 ⁇ / b> B, and 32 ⁇ / b> D are arranged in the porous layer 33. More specifically, as shown in FIG. 7A, by applying a positive voltage for a longer time than when displaying magenta, as shown in FIG. 7B, in the initial state, the back side S2 side of the migrating particles 32A and 32B.
  • the positioned migrating particles 32C move to the display surface S1. Thereafter, when a negative voltage is applied, the migrating particles 32A, 32B, 32C, and 32D start to move toward the back surface S2. At this time, since the migrating particles 32A and 32B have a higher moving speed than the migrating particles 32C, they move to the back surface S2 side before the migrating particles 32C.
  • the migrating particles 32C are arranged on the outermost surface of the porous layer 33, and the migrating particles 32A, 32B, and 32D are arranged in the porous layer 33. That is, the display color of the pixel including the electrophoretic element 30 is yellow.
  • the display color of the pixel including the electrophoretic element 30 is black, for example, a positive voltage is applied for a longer time than yellow display, and then a negative voltage is applied from yellow display.
  • the migrating particles 32D colored black on the outermost surface of the porous layer 33 are in a state in which the migrating particles 32A, 32B, and 32C are arranged in the porous layer 33.
  • the display color of the pixel including the electrophoretic element 30 is black.
  • the electrophoretic element 30 controls the direction (positive / negative) and application time of the applied voltage, so that it is multicolored, in this case, cyan, magenta, yellow, black, and White five-color display is possible.
  • FIG. 8A and FIG. 8B are a conceptual diagram (FIG. 8A) showing the movement of electrophoretic particles in an electrophoretic element as a comparative example, and a waveform diagram of an applied voltage (FIG. 8B).
  • This electrophoretic element controls the display color only by the difference in the moving speed of the electrophoretic particles of each color, like the electrophoretic element provided in the display device described in Patent Document 1.
  • the electrophoretic element has four types of electrophoretic particles 132A, 132B, 132C, and 132D as in the present embodiment.
  • the size and the color of each migrating particle 132A, 132B, 132C, 132D are the same as those of the migrating particle 32A, 32B, 32C, 32D of the present embodiment, respectively.
  • the electrophoretic particles 132C are all localized on the back surface S200 in the initial state. For this reason, in order to move the yellow electrophoretic particles 132C to the display surface S100, it takes a longer time than the electrophoretic element 30 of the present embodiment (see FIGS. 8A and 8B).
  • the time is longer than that of the electrophoretic element 30. Cost.
  • examples of a reflective display device capable of multicolor display include a display device provided with a color filter.
  • the color filter when the color filter is provided, there is a risk that the contrast and the brightness may be significantly reduced due to a decrease in reflectance due to the provision of the color filter and absorption of reflected light by the color filter.
  • the migrating particles 32 four types of migrating particles 32A, 32B, 32C, which have different average particle sizes and are colored in different colors for each average particle size. 32D was used.
  • the porous layer 33 is composed of four types of porous layers 33A, 33B, 33C, and 33D having different average pore diameters of the pores 333, and these average pore diameters decrease from the display surface S1 side to the back surface S2 side. Laminated in order. Thereby, the moving distance of each color migrating particle 32A, 32B, 32C, 32D is limited by the particle diameter and the pore diameter of the porous layers 33A, 33B, 33C, 33D.
  • the migrating particles 32A, 32B, 32C, and 32D are localized on the back surface S2 side of the porous layers 33A, 33B, 33C, and 33D that can pass, respectively, in the initial state, for example.
  • the moving distance of the particles 32A, 32B, 32C, 32D is shorter in the migrating particles 32A, 32B, 32C other than the migrating particle 32D having the smallest particle size.
  • the plurality of types of migrating particles 32 having different average particle diameters and different colors for each average particle diameter, and the display surface S1 side to the back surface S2 side.
  • the electrophoretic element 30 including a plurality of types of porous layers 33 stacked in order of decreasing average pore diameter is used as a display element.
  • the position of the migrating particle 32 (32A, 32B, 32C, 32D) in the initial state is controlled by the pore diameter of the laminated porous layer 33 (33A, 33B, 33C, 33D).
  • the migrating particle 32A having the largest particle size is arranged at the position closest to the display surface S1
  • the migrating particle 32D having the smallest particle size is arranged at the position farthest from the display surface S1. Therefore, when performing a certain color display, the electrophoretic particles exhibiting a desired color are arranged on the display surface S1 by applying a voltage, and the electrophoretic particles of other colors are moved and concealed in the porous layer. It is possible to shorten the sorting time. That is, it is possible to shorten the time required for display switching. Therefore, it is possible to provide the display device 1 capable of multicolor display while improving display quality.
  • FIG. 9 illustrates a cross-sectional configuration of a display device (display device 2) according to Modification 1 of the above embodiment.
  • the display device 2 is applied to various electronic devices such as an electronic paper display, for example, an electronic paper display that generates contrast by using an electrophoretic phenomenon and displays an image.
  • the display device 2 includes, for example, a display layer including the electrophoretic element 30 between the drive substrate 10 and the counter substrate 20 that are disposed to face each other with the spacer 35 interposed therebetween.
  • the electrophoretic element 40 includes an insulating liquid 41 including electrophoretic particles 42 and a porous layer 43 having a plurality of pores.
  • the porous layer 43 has a fibrous structure and non-migrating particles held by the fibrous structure (none of which are shown).
  • FIG. 9 schematically shows the configuration of the electrophoretic element 40 and may differ from the actual size and shape.
  • the electrophoretic element 40 of the present modification has a plurality of types of average particle diameters, for example, the electrophoretic particles 42A and the electrophoretic particles 42B having different average particle diameters as the electrophoretic particles 42.
  • the porous layer 43 includes a plurality of types of average pore diameters, for example, a porous layer 43A and a porous layer 43B having different average pore diameters.
  • the migrating particles 42A and 42B and the porous layers 43A and 43B are charged, and the charge amounts are different from those of the above embodiment.
  • positioned at the display surface S1 side and the porous layer 43A with a large hole diameter at the back surface S2 side is different from the said embodiment.
  • the insulating liquid 41 is, for example, any one type or two or more types of non-aqueous solvents such as organic solvents, and specifically includes paraffin or isoparaffin. Yes. It is preferable that the viscosity and refractive index of the insulating liquid 41 are as low as possible. This is because the mobility (response speed) of the migrating particles 32 is improved, and the energy (power consumption) required to move the migrating particles 32 is lowered accordingly. Moreover, since the difference between the refractive index of the insulating liquid 41 and the refractive index of the porous layer 33 is increased, the light reflectance of the porous layer 33 is increased. Note that a weak conductive liquid may be used instead of the insulating liquid 41.
  • the insulating liquid 41 may contain various materials (for example, a colorant, a charge control agent, a dispersion stabilizer, a viscosity modifier, a surfactant, or a resin) as necessary.
  • the electrophoretic particles 42 are one or more charged particles that are electrically movable, and are dispersed in the insulating liquid 41.
  • the migrating particles 42 in the present modification include the migrating particles 42A and 42B having different average particle diameters, and are each composed of one or two or more charged particles.
  • the migrating particles 42A and 42B are colored in different colors. Specifically, the electrophoretic particles 42A and 42B are colored, for example, red (electrophoretic particles 42A) and black (electrophoretic particles 42B).
  • the particle size of the migrating particles 42 is preferably in the range of, for example, 0.1 ⁇ m or more and 2 ⁇ m or less, and the migrating particles 42A and 42B have, for example, 0.2 ⁇ m (migrating particles 42A) and 0.3 ⁇ m in this range. (Electrophoretic particle 42B).
  • the average particle diameter of each migrating particle 42A and 42B is not limited to the said range, For example, an average particle diameter should just be 0.1 micrometer or more.
  • the migrating particles 42A and 42B may be any of organic pigments, inorganic pigments, dyes, carbon materials, metal materials, metal oxides, glass, polymer materials (resins), and the like, as with the migrating particles 32 in the above embodiment. Or one kind or two or more kinds of particles (powder).
  • the content (concentration) of the migrating particles 42A and 42B in the insulating liquid 41 is not particularly limited, but the entire migrating particle 42 is preferably, for example, 0.1 wt% to 10 wt%. This is because the shielding property of the porous layer 33 by the migrating particles 32 and the concealing property and mobility of the migrating particles 32 by the porous layer 33 are ensured. If the amount is less than 0.1% by weight, the migrating particles 32 may hardly shield the porous layer 33. On the other hand, when the amount is more than 10% by weight, the dispersibility of the migrating particles 32 is lowered, so that the migrating particles 32 are difficult to migrate and may be aggregated in some cases. For example, both the migrating particles 42A and the migrating particles 42B are preferably 0.1% by weight to 4% by weight although the migrating particles 42A and 42B depend on the particle size, surface modification, or material.
  • the migrating particles 42A and 42B in this modification are charged and have different charge amounts.
  • This difference in charge amount can be added, for example, by performing a surface treatment.
  • a charge difference can be provided by modifying an electron-withdrawing functional group having a different charge amount.
  • a charge difference can be provided by modifying functional groups having electron donating properties having different charge amounts.
  • the charge difference can also be provided by changing the amount of the functional group to be modified on the surfaces of the migrating particles 42A and 42B.
  • the charge amounts of the migrating particles 42A and the migrating particles 42B are determined from the relationship with the charge amounts of the porous layer 43A and the porous layer 43B described later. This is because the moving speed of the migrating particles 42A and 42B at the time of voltage application is differentiated to further improve the display switching speed. Specifically, the mobility of the migrating particles 42 increases in the case of a combination with a small charge difference between the migrating particles 42 and the porous layer 43, and the migration of the migrating particles 42 in a combination with a large charge difference. The degree is small. If the charge difference is too large, the migrating particles 42 cannot pass through the porous layer 43.
  • the charge amount of the migrating particles 42B is preferably larger than the charge amount of the migrating particles 42A having a small particle size, for example.
  • the charge amount of the migrating particles 42A is preferably 10 mV or more and 50 mV or less, for example, and the charge amount of the migrating particles 42B is preferably 20 mV or more and 100 mV or less, for example.
  • the porous layer 43 is a three-dimensional solid structure (irregular network structure such as a nonwoven fabric) formed of a fibrous structure as in the above embodiment.
  • the porous layer 43 in this modification has two types of porous layers 43A and porous layers 43B having different pore sizes.
  • the porous layers 43A and 43B are charged and have different charge amounts.
  • the order of stacking the porous layers 43A and 43B is such that a porous layer 43A having a small average pore diameter is arranged on the display surface S1 side, and a porous layer 43B having a large average pore diameter is arranged on the back surface S2 side. Yes.
  • the materials described in the above embodiment can be used.
  • the porous layer 43A disposed on the display surface S1 side may have light reflectivity, but in this modification, the pore size of the porous layer 43A cannot pass through the migrating particles 42B, so that light transmission is possible. It is preferable to have properties.
  • the fibrous structure constituting the porous layer 43A is formed without including non-electrophoretic particles that add optical reflection characteristics.
  • the porous layer 43B disposed on the back surface S2 side is composed of a fibrous structure including one or two or more non-electrophoretic particles, like the porous layer 33 in the above embodiment, and the electrophoretic particles 42A, It has a light reflection characteristic different from 42B.
  • the average pore diameter of the porous layers 43A and 43B is not particularly limited, but the average pore diameter of the porous layer 43B disposed on the back surface S2 side is preferably as large as possible. This is because the migrating particles 42A and 42B easily pass through the pores. For this reason, the average pore diameter of the pores of the porous layer 43B is preferably in the range of 0.5 ⁇ m or more and 1.5 ⁇ m or less, for example. On the other hand, it is desirable that the average pore size of the pores of the porous layer 43A is a pore size through which the large migrating particles 42B cannot pass. For this reason, it is preferable that the average pore diameter of the pores of the porous layer 43B is, for example, in the range of 0.1 ⁇ m to 5 ⁇ m.
  • the thickness of the porous layers 43A and 43B is not particularly limited.
  • the thickness of the entire porous layer 43 is preferably, for example, 5 ⁇ m to 100 ⁇ m. This is because the concealability of the porous layer 43 is enhanced and the migrating particles 42 easily pass through the pores.
  • the thickness of the porous layer 43A is not particularly limited.
  • the thickness of the mass layer 43B is preferably a thickness that can shield the migrating particles 42B having a large particle diameter, and is preferably in the range of 2 ⁇ m to 15 ⁇ m, for example.
  • the porous layers 43A and 43B are charged and have different charge amounts.
  • the porous layers 43A and 43B can be charged, for example, by containing an inorganic pigment.
  • the difference in charge amount can be provided, for example, by changing the surface treatment method.
  • the charge amount of the porous layer 43A and the porous layer 43B is determined from the relationship with the charge amount of the migrating particles 42A and the migrating particles 42B.
  • the charge amount of the porous layer 43A disposed on the display surface S1 side is preferably smaller than the charge amount of the porous layer 43B.
  • the charge amounts of the porous layer 43A and the porous layer 43B are, for example, 0 mV or more and 50 mV or less (porous layer 43A), respectively.
  • it is preferably 20 mV or more and 100 mV or less (porous layer 43B).
  • the electrophoretic element 40 of this modification includes the electrophoretic particles 42A and 42B having different average particle diameters and the porous layers 43A and 43B having different average pore diameters.
  • the electrophoretic particles 42A and 42B and the porous layers 43A and 43B are charged and have different charge amounts. Specifically, the charged amount of the electrophoretic particle 42B having a larger particle diameter than that of the electrophoretic particle 42A is increased, and the charged amount of the porous layer 43B having a larger pore diameter than that of the porous layer 43A is increased. Thereby, the difference in the moving speed of the migrating particles 42A and 42B at the time of voltage application is increased. Therefore, it is possible to further reduce the time required for display switching. Therefore, it is possible to provide the display device 2 capable of multicolor display with improved display quality.
  • the porous layers 43A and 43B having different pore diameters are arranged, the porous layer 43A having a small pore diameter is arranged on the display surface S1, and the porous layer 43B having a large pore diameter is arranged on the back surface S2.
  • the migrating particles 42A and 42B having different particle sizes cannot pass through the porous layer 43A.
  • the pore size is large on the display surface S1 side. You may make it arrange
  • the porous layer 43A preferably has the same light reflection characteristics as the porous layer 43B, and preferably contains non-electrophoretic particles.
  • the charge amount of the migrating particle 42B is 50 mV or more and 250 mV or less (same for the porous layer 43B) with respect to the charge amount of 10 mV or more and 50 mV or less for the migrating particle 42A (same for the porous layer 43A).
  • the particle diameters of the migrating particles 42A and 42B are different from each other, but may be the same.
  • the porous layers 43A and 43B may have the same pore diameter.
  • the charge amount and the difference between the migrating particles 42A and 42B and the charge amount and the difference between the porous layers 43A and 43B may be the same as the above range. For example, by setting the difference to 25 mV or more Thus, it is possible to realize a display device capable of multicolor display only by the difference in charge amount between the migrating particles 42A and 42B and the porous layers 43A and 43B.
  • 10A, 10B, and 10C schematically show the display operation of the electrophoretic particles 52A and 52B in the electrophoretic element 50 including the electrophoretic particles 52A and 52B having the same particle diameter and the porous layers 53A and 53B having the same pore diameter. It is a representation.
  • the migrating particles 52A and 52B and the porous layers 53A and 53B have different charge amounts. Specifically, for example, the migrating particles 52A are charged to 25 mV, the migrating particles 52B are charged to 100 mV, the porous layer 53A is charged to 0 mV, and the porous layer 53B is charged to 100 mV.
  • the migrating particles 52A are colored red, the migrating particles 52B are colored black, and the porous layer 53A disposed on the display surface S1 side is light transmissive.
  • the migrating particles 52A and 52B are both moved to the back surface S2
  • the migrating particles 52A and 52B are concealed by the porous layer 53B and displayed white.
  • the electrophoretic particles 52B In the initial state, when a voltage is applied for a certain period of time, in the electrophoretic element 50, the electrophoretic particles 52B having a larger charge amount move toward the display surface S1 before the electrophoretic particles 52A.
  • the potential difference between the migrating particles 52B and the porous layer 53A is large, the migrating particles 52B cannot pass through the porous layer 53A and remain at the boundary between the porous layer 53A and the porous layer 53B.
  • the migrating particle 52B remains at the boundary between the porous layer 53A and the porous layer 53B, and the migrating particle 52A has a lower moving speed than the migrating particle 52B. Returns to the back surface S2 side (pixel electrode side). As a result, the electrophoretic element 50 displays black. Further, when a voltage is applied for a longer time than when displaying black from the initial state, both the migrating particles 52A and the migrating particles 52B move to the boundary between the porous layer 53A and the porous layer 53B.
  • the migrating particles 52A pass through the porous layer 53A and reach the display surface S1. Thereafter, when the applied voltage is erased, as shown in FIG. 10C, the migrating particles 52A remain on the display surface S1, and the migrating particles 52B remain on the boundary between the porous layer 53A and the porous layer 53B.
  • the electrophoretic element 50 is displayed in red by the child.
  • FIG. 11 illustrates a cross-sectional configuration of a display device (display device 4) according to Modification 2 of the above embodiment.
  • the display device 4 is applied to various electronic devices such as an electronic paper display, for example, an electronic paper display that displays an image by generating contrast using an electrophoretic phenomenon.
  • the display device 4 includes, for example, a display layer including the electrophoretic element 60 between the drive substrate 10 and the counter substrate 20 that are disposed to face each other with the spacer 35 interposed therebetween.
  • the electrophoretic element 60 is configured to include an electrophoretic particle 62 and a porous layer 63 having a plurality of pores in an insulating liquid 61. Note that FIG. 11 schematically shows the configuration of the electrophoretic element 60 and may differ from the actual size and shape.
  • the electrophoretic element 60 of this modification has a plurality of types of electrophoretic particles having different average particle diameters (for example, electrophoretic particles 62A and electrophoretic particles 62B having different average particle diameters) as the electrophoretic particles 62.
  • the electrophoretic element 60 has a plurality of types of porous layers having different average pore diameters as the porous layer 63.
  • the porous layer 63 includes, for example, three porous layers 63A, 63B, and 63C, and the porous layer 63B has a larger average pore diameter than the porous layer 63A.
  • the porous layer 63A having a small average pore diameter is disposed on the display surface S1 side, and the porous layer 63B having a larger average pore diameter than the porous layer 63A is disposed on the back surface S2 side, and has light transmission properties.
  • the display device 4 of the present modification further has a configuration in which a porous layer 63C having optical reflection characteristics is disposed on the back surface S2 side of the porous layer 63B.
  • the insulating liquid 61 is, for example, any one type or two or more types of non-aqueous solvents such as organic solvents, and specifically includes paraffin or isoparaffin. Yes. It is preferable that the viscosity and refractive index of the insulating liquid 61 be as low as possible. This is because the mobility (response speed) of the migrating particles 62 is improved, and the energy (power consumption) required to move the migrating particles 62 is lowered accordingly. Moreover, since the difference between the refractive index of the insulating liquid 61 and the refractive index of the porous layer 63 becomes large, the light reflectance of the porous layer 63 becomes high.
  • the insulating liquid 61 may contain various materials (for example, a colorant, a charge control agent, a dispersion stabilizer, a viscosity modifier, a surfactant, or a resin) as necessary.
  • the electrophoretic particles 62 are one or more charged particles that are electrically movable and are dispersed in the insulating liquid 61.
  • the migrating particle 62 in the present modification includes the migrating particles 62A and 62B having different average particle diameters, and each is composed of one or more charged particles.
  • the migrating particles 62A and 62B are colored in different colors. Specifically, the migrating particles 62A are colored, for example, red (R), and the migrating particles 62B are colored, for example, black (B).
  • the particle size of the migrating particles 62 is preferably in the range of 0.1 ⁇ m to 2 ⁇ m, for example, and the migrating particles 62A and 62B are within this range, for example, 0.3 ⁇ m (migrating particles 62A) and 0.2 ⁇ m. (Electrophoretic particle 62B).
  • the average particle diameter of the migrating particles 62A and 62B is not limited to the above range, and for example, the average particle diameter may be 0.1 ⁇ m or more.
  • the migrating particles 62A and 62B are, for example, any of organic pigments, inorganic pigments, dyes, carbon materials, metal materials, metal oxides, glass, polymer materials (resins), and the like, similar to the migrating particles 62 in the above embodiment. Or one kind or two or more kinds of particles (powder).
  • the content (concentration) of the migrating particles 62A and 62B in the insulating liquid 61 is not particularly limited, but the entire migrating particle 62 is preferably, for example, 0.1 wt% to 10 wt%. This is because the shielding property of the porous layer 33 by the migrating particles 32 and the concealing property and mobility of the migrating particles 32 by the porous layer 33 are ensured. If the amount is less than 0.1% by weight, the migrating particles 62 may not easily shield the porous layer 63.
  • both the migrating particles 62A and the migrating particles 62B are preferably 0.1% by weight to 4% by weight although the migrating particles 62A and 62B depend on the particle size, surface modification, or material.
  • the migrating particles 62A and 62B in the present modification are charged with the same polarity and have different average moving speeds.
  • the average moving speed of the migrating particles 62A is smaller than the average moving speed of the migrating particles 62B.
  • the difference in the average moving speed is determined by, for example, the charge amount possessed by the migrating particles 62A and 62B.
  • the difference in charge amount can be added, for example, by performing a surface treatment as in the first modification.
  • a charge difference can be provided by modifying an electron-withdrawing functional group having a different charge amount. .
  • a charge difference can be provided by modifying functional groups having electron donating properties having different charge amounts.
  • the charging difference can also be provided by changing the amount of the functional group to be modified on the surfaces of the migrating particles 62A and 62B.
  • the porous layer 63 is, for example, a three-dimensional structure (irregularity such as a nonwoven fabric) formed by a fibrous structure (fibrous structure 331) as shown in FIG. Network structure).
  • the porous layer 63 in the present modification is composed of two kinds of porous layers 63A and 63B having different light diameters and having light transmission properties, and a porous layer 63C having optical reflection characteristics. Yes.
  • the order of lamination of the light-transmitting porous layer 63A and porous layer 63B is such that the porous layer 63A having a small average pore diameter on the display surface S1 side and the pore having a large average pore diameter on the back surface S2 side.
  • Layer 63B is disposed.
  • the porous layer 63C having optical reflection characteristics (light reflectance) is disposed on the back surface S2 side of the porous layer 63B.
  • the materials mentioned in the above embodiment can be used.
  • the light-transmitting porous layers 63A and 63B are composed of a fibrous structure that does not include non-electrophoretic particles (non-electrophoretic particles 332) as shown in FIG.
  • the porous layer 63C disposed on the back surface S2 side is composed of a fibrous structure including one or two or more non-electrophoretic particles, like the porous layer 63 in the above embodiment, and the electrophoretic particles 62A. , 62B have different light reflectivity.
  • the porous layers 63A and 63B preferably contain particles that do not reflect visible light (non-visible light particles).
  • Examples of the particles that do not reflect visible light include titania (TiO 2 ) having a particle size of 250 nm or less. This is because the holding performance of the migrating particles 62A and 62B in the porous layers 63A and 63B may be improved by forming the porous layers 63A and 63B using the fibrous structure containing TiO 2. is there.
  • the average pore sizes of the porous layers 63A and 63B are determined by the migrating particles 62A and 62B, respectively.
  • the average pore diameter of the pores of the porous layer 63A is preferably a pore diameter that allows the migrating particles 62B to pass through but does not allow the migrating particles 62A having a larger average particle diameter to pass through, for example, less than 0.3 ⁇ m. It is preferable that The average pore size of the porous layer 63B is not particularly limited as long as the migrating particles 62A and the migrating particles 62B can pass through, but is preferably as large as possible. This is because the migrating particles 62A and 62B easily pass through the pores.
  • the average pore diameter of the pores of the porous layer 63B is, for example, in the range of 0.3 ⁇ m to 5 ⁇ m. Further, the average pore size of the porous layer 63C only needs to allow the migrating particles 62A and the migrating particles 62B to pass through, and may be the same average pore size as the porous layer 63B or a larger average pore size.
  • the thickness of the entire porous layer 63 is not particularly limited, but is preferably 5 ⁇ m to 100 ⁇ m, for example.
  • the thicknesses of the porous layer 63A, the porous layer 63B, and the porous layer 63C with respect to the entire porous layer 63 are determined as follows, for example. First, the thickness (W1 (porous layer 63A) and W2 (porous layer 63B)) of the light-transmitting porous layers (porous layer 63A and porous layer 63B) is such that migrating particles 62B having a higher moving speed.
  • (W1 + W2) W ⁇ (V2 / V1), where V1 is the average migration speed of V2, V2 is the average migration speed of the migrating particles 62A, and W is the total thickness of the porous layer 63.
  • the thickness (W3) of the porous layer 63C having light reflection characteristics is a thickness obtained by subtracting the thickness (W1 + W2) of the porous layer 63A and the porous layer 63B from the thickness (W) of the entire porous layer 63.
  • the porous layer 63A and the porous layer 63B having light transmittance are provided on the display surface S1 side, and the porous layer 63A having a small average pore diameter is provided on the display surface S1 side.
  • the porous layer 63B having a larger average pore diameter than the porous layer 63A is arranged on the back surface S2 side.
  • a porous layer 63C having light reflectivity is disposed on the back surface S2 side of the porous layer 63B.
  • the electrophoretic particles 62A and the electrophoretic particles 62B having a smaller particle diameter than the electrophoretic particles 62A are used as the electrophoretic particles 62.
  • the average particle size of the migrating particles 62A and 62B and the average pore size of the porous layers 63A, 63B, and 63C are such that the migrating particles 62B can pass through the pores of the porous layer 63A, but the migrating particles 62A are fine particles of the porous layer 63A.
  • the size is such that it cannot pass through the hole.
  • the pores of the porous layer 63B and the porous layer 63C are sized so that both the migrating particles 62A and the migrating particles 62B can pass through.
  • the application time of the voltage applied between the pixel electrode 14 and the counter electrode 22 is controlled as in the above embodiment, so that the pixel electrode 14 and the counter electrode 22
  • the average distribution position of the migrating particles 62A (red; R) and 62B (black; B) can be controlled to switch between red display (R), black display (B), and white display (W).
  • the electrophoretic particles 62A and the electrophoretic particles 62B are charged, and the distribution of the desired electrophoretic particles 62A and electrophoretic particles 62B can be controlled by the electric field and time applied between the pixel electrode 14 and the counter electrode 22. .
  • the migrating particles 62A and 62B are distributed in the light-transmitting porous layer 63A or the porous layer 63B, respectively, or on the display surface S1 side of the light-reflecting porous layer 63C. By approaching, the colors of the migrating particles 62A and the migrating particles 62B are visually recognized from the display surface.
  • the migrating particles 62 ⁇ / b> A and 62 ⁇ / b> B are hidden in the porous layer 73 ⁇ / b> C by moving into the porous layer 63 ⁇ / b> C (back S ⁇ b> 2 side), and diffused light from the porous layer 63 ⁇ / b> C is visually recognized from the display surface. Is done.
  • FIG. 11 shows the change over time of the potential difference with respect to the display surface S1 side on the back surface S2 side as an example of the driving method of the display device 4.
  • FIG. 12 shows the time change of the average distribution position (average movement position) of the migrating particles 62A (red; R) and 62B (black; B) due to the time change of the potential difference with respect to the display surface S1 side on the back surface S2 side shown in FIG. It represents.
  • the electrophoretic particles 62A and 62B are charged positively (+) and have the electrophoretic speed shown in Table 1.
  • the display surface S1 is displayed in white (starting point 0 seconds).
  • the positively charged migrating particles 62A and 62B begin to move toward the display surface S1, and the potential difference is reduced to 0 when the migrating particle 62B having a fast migrating speed reaches the display surface S1.
  • the migrating particles 62A having a low migrating speed are located in the porous layer 63C that is white due to the non-migrating particles, the migrating particles 62A are concealed by the porous layer 63C. Thereby, the display color of the display surface S1 becomes black (B).
  • the migrating particles 62A staying between the display surface S1 and the back surface S2 (in the porous layer 63C) move toward the display surface S1.
  • the migrating particles 62A reach the interface between the porous layer 63A and the porous layer 63B having optical transparency, the potential on the back surface S2 side is reversed and the potential is lowered with respect to the display surface S1, so that the migration speed is high.
  • the migrating particle 62B moves to the back surface S2 side earlier than the migrating particle 62A.
  • the migrating particles 62B When the potential difference is set to 0 when the migrating particles 62B reach the back surface S2, the migrating particles 62B are distributed in the light-reflecting porous layer 63C and are hidden by the porous layer 63C. During this movement, the migrating particle 62A moves toward the back surface S2, but its moving speed is slow, and since the porous layer 63B having light permeability is disposed, the saturation ( Red) is secured. Thereby, the display color of the display surface S1 is red (R). Further, when the potential on the back surface S2 side is lowered with respect to the display surface S1, the migrating particles 62A staying on the porous layer 63B move to the back surface S2 side. If the potential difference is set to 0 when the migrating particles 62A reach the back surface S2, both the migrating particles 62A and 62B are concealed by the porous layer 63C, and the display color is white (W).
  • FIG. 14 shows a change with time of a potential difference with respect to the display surface S1 side on the back surface S2 side as an example of a driving method of a general display device.
  • a general display device includes electrophoretic particles that are colored in red (red electrophoretic particles; R) and electrophoretic particles that are colored black (black electrophoretic particles; B).
  • a porous layer having transparency and a porous layer having light reflectivity are laminated one by one. Both of the two porous layers have pores having a pore diameter through which red electrophoretic particles and black electrophoretic particles can pass.
  • FIGS. 14 and 15 it can be seen that a general display device requires more time for switching the display color than the display device 4 of the present modification. This is because the moving distance of the red migrating particles having a slower moving speed is larger than that of the display device 4. That is, in this modification, a plurality of porous layers are stacked so that the average pore diameter decreases from the back surface S2 toward the display surface S1. Specifically, since the porous layer 63A having a pore diameter equal to or smaller than the average particle diameter of the migrating particles 62A is disposed on the display surface S1, the moving distance of the migrating particles 62A is shortened, and the display speed is increased accordingly. Colors (black (B), red (R), and white (W) in this modification) can be switched.
  • 16A and 16B show the external configuration of an electronic book.
  • the electronic book includes, for example, a display unit 110, a non-display unit 120, and an operation unit 130.
  • the operation unit 130 may be provided on the front surface of the non-display unit 120 as illustrated in FIG. 16A, or may be provided on the upper surface as illustrated in FIG. 16B.
  • the display unit 110 is configured by the display device 1 (or 2, 3).
  • the display device 1 (or the display devices 2 to 4) may be mounted on a PDA (Personal Digital Assistants) having the same configuration as the electronic book shown in FIGS. 16A and 16B.
  • PDA Personal Digital Assistants
  • FIG. 17 shows the appearance of a tablet personal computer.
  • the tablet personal computer has, for example, a touch panel unit 210 and a housing 220, and the touch panel unit 210 is constituted by the display device 1 (or display devices 2 to 4).
  • the display devices 1 to 4 of the above-described embodiments and modifications may be applied to an electronic bulletin board or the like.
  • the embodiment and modifications 1 and 2 have been described, but the present disclosure is not limited to the aspects described in the embodiment and the like, and various modifications are possible.
  • the same number of types of migrating particles 32 having different particle sizes and the same number of types of porous layers 33 having different pore sizes of the pores 333 are used. May be.
  • the porous layers 33 having different pore diameters of the pores 333 may be stacked with a larger number of layers than the types of the migrating particles 32 having different particle diameters.
  • the structure provided with the insulating liquid 31, the electrophoretic particle 32, and the porous layer 33 was illustrated as the electrophoretic element 30 (display layer), the structure of the electrophoretic element 30 is this. It is not limited to the one using the porous layer 33 as long as it can form a contrast by light reflection for each pixel using the electrophoresis phenomenon.
  • the modification 1 may be combined with the modification 2 to charge the porous layer 63, for example.
  • this indication can also take the following structures.
  • a plurality of types of migrating particles having different average particle sizes A display device comprising a plurality of porous layers formed of a fibrous structure and having different average pore diameters.
  • the display device according to (1) including a display surface, wherein the plurality of porous layers are laminated to each other, and an average pore diameter decreases from the display surface toward the back surface.
  • the display device according to (1) or (2), wherein the plurality of types of migrating particles have different colors.
  • the plurality of porous layers have a first layer from the display surface side and a second layer having a smaller average pore diameter than the first layer, The display device according to any one of (2) to (4), wherein the thickness of the first layer is larger than that of the second layer.
  • an average particle diameter of the plurality of types of migrating particles is 100 nm to 2 ⁇ m.
  • the display device according to any one of (1) to (8), wherein an average pore diameter of the plurality of porous layers is 0.1 ⁇ m or more and 5 ⁇ m or less.
  • the porous layer has non-migrating particles held in the fibrous structure, The non-electrophoretic particles have a light reflectance higher than that of the electrophoretic particles, the electrophoretic particles display dark, and the non-electrophoretic particles and the fibrous structure perform bright display.
  • the display apparatus in any one of. (11)
  • the electrophoretic particles and the non-electrophoretic particles are composed of at least one of an organic pigment, an inorganic pigment, a dye, a carbon material, a metal material, a metal oxide, glass, and a polymer material.
  • the plurality of porous layers have a third layer from the display surface side and a fourth layer having a larger average pore diameter than the third layer, The display device according to (12), wherein each of the third layer and the fourth layer has optical transparency.
  • the plurality of porous layers further have a fifth layer on the back side of the fourth layer, The display device according to (13), wherein the fifth layer has an optical reflection characteristic different from that of the plurality of types of migrating particles.
  • the particles that do not reflect visible light are titania (TiO 2 ) having a particle size of 250 nm or less.
  • the fibrous structure is made of an acrylic resin.

Abstract

A display device (1) according to the present invention is provided with a plurality of types of migrating particles (32) with mutually different average grain diameters, and a plurality of porous layers (33) formed with a fibrous structure and having mutually different average pore diameters.

Description

表示装置および電子機器Display device and electronic device
　本開示は、電気泳動現象を利用して画像表示を行う表示装置および電子機器に関する。 The present disclosure relates to a display device and an electronic apparatus that perform image display using an electrophoresis phenomenon.
　近年、携帯電話機または携帯情報端末機器（ＰＤＡ）等の多様な電子機器の普及に伴い、低消費電力で高品位画質の表示装置に関する需要が高まっている。中でも、最近では、電子書籍の配信事業の誕生に伴い、文字情報を長時間読むことを目的とした読書用途の電子書籍端末が注目されているため、その用途に適した表示品位を有する表示装置が望まれている。読書用途の表示装置としては、コレステリック液晶型、電気泳動型、電気酸化還元型またはツイストボール型等の表示装置が提案されているが、中でも、反射型に分類される表示装置が好ましい。紙と同様に外光の反射（散乱）を利用して明表示するため、紙に近い表示品位が得られるからである。また、バックライトが不要であるため、消費電力が抑えられるからである。 In recent years, with the widespread use of various electronic devices such as mobile phones and personal digital assistants (PDAs), there is an increasing demand for display devices with low power consumption and high image quality. Among them, recently, with the birth of the electronic book distribution business, electronic book terminals for reading purposes aimed at reading character information for a long time have been attracting attention, so a display device having a display quality suitable for that purpose Is desired. As display devices for reading use, display devices of a cholesteric liquid crystal type, an electrophoretic type, an electrooxidation reduction type, a twist ball type, and the like have been proposed, and among them, a display device classified as a reflection type is preferable. This is because bright display is performed using reflection (scattering) of external light as in the case of paper, and display quality close to that of paper can be obtained. In addition, since a backlight is unnecessary, power consumption can be suppressed.
　反射型の表示装置の有力候補としては、電気泳動現象を利用して明暗（コントラスト）を生じさせる電気泳動型の表示装置が挙げられる。電気泳動型の表示装置の表示方法については様々な検討がなされている。具体的には、絶縁性液体中に光学的反射特性および極性が異なる２種類の荷電粒子を分散させて、その極性の違いを利用して各荷電粒子を移動させる方法が提案されている。この方法では、電界に応じて２種類の荷電粒子の分布が変化するため、光学的反射特性の違いを利用してコントラストが生じる。 As a promising candidate for a reflective display device, an electrophoretic display device that produces a contrast (contrast) using an electrophoretic phenomenon can be cited. Various studies have been made on display methods of electrophoretic display devices. Specifically, a method has been proposed in which two types of charged particles having different optical reflection characteristics and polarities are dispersed in an insulating liquid, and each charged particle is moved using the difference in polarity. In this method, since the distribution of the two types of charged particles changes according to the electric field, contrast is generated using the difference in optical reflection characteristics.
　電気泳動型の表示装置では、上記のように反射光のコントラストを利用して表示を行うため、基本的にモノクロ（モノクローム）表示となるが、例えば、特許文献１では、対向する一対の基板の間に空隙を有する層を配設すると共に、それぞれ、色および粒径の異なる２種類の泳動粒子を用いた画像表示装置が開示されている。一対の基板の間に配設された層が有する空隙は、２種類の泳動粒子の一方が侵入できない大きさになっており、これによって多色表示を可能としている。 In the electrophoretic display device, since display is performed using the contrast of reflected light as described above, the display is basically monochrome (monochrome) display. However, in Patent Document 1, for example, a pair of opposing substrates is displayed. There is disclosed an image display device in which a layer having a gap is provided between the two, and two types of migrating particles having different colors and particle sizes are used. The gap of the layer disposed between the pair of substrates is large enough to prevent one of the two types of migrating particles from entering, thereby enabling multicolor display.
特開２００７－２４０７５８号公報JP 2007-240758 A
　しかしながら、特許文献１の画像表示装置では、表示面における複数の泳動粒子の濃度の制御方法は確立されておらず、実際に色の異なる複数の泳動粒子を用いて多色表示を行うことが困難であった。また、表示の切り替えは、泳動粒子の移動速度の差によって行われるため一定の時間を要するという問題があった。 However, in the image display device of Patent Document 1, a method for controlling the concentration of a plurality of migrating particles on the display surface has not been established, and it is difficult to actually perform multicolor display using a plurality of migrating particles having different colors. Met. Further, since the display is switched depending on the difference in moving speed of the migrating particles, there is a problem that it takes a certain time.
　従って、表示品位を向上させつつ、多色表示が可能な表示装置および電子機器を提供することが望ましい。 Therefore, it is desirable to provide a display device and an electronic device capable of multicolor display while improving display quality.
　本開示の一実施形態の表示装置は、互いに平均粒径の異なる複数種類の泳動粒子と、繊維状構造体により形成されると共に、互いに平均孔径が異なる複数の多孔質層とを備えたものである。 A display device according to an embodiment of the present disclosure includes a plurality of types of migrating particles having different average particle sizes, and a plurality of porous layers that are formed of a fibrous structure and have different average pore sizes. is there.
　本開示の一実施形態の電子機器は、上記本開示の一実施形態の表示装置を有するものである。 An electronic apparatus according to an embodiment of the present disclosure includes the display device according to the embodiment of the present disclosure.
　本開示の一実施形態の表示装置および一実施形態の電子機器では、互いに平均粒径の異なる複数種類の泳動粒子と、繊維状構造体により形成されると共に、互いに平均孔径が異なる複数の多孔質層とを用いることにより、泳動粒子の移動距離が泳動粒子の粒径および多孔質層の孔径によって調整される。 In the display device according to an embodiment of the present disclosure and the electronic apparatus according to the embodiment, a plurality of types of migrating particles having different average particle diameters and a plurality of porous particles having a different average pore diameter from each other are formed by a fibrous structure. By using the layer, the moving distance of the migrating particles is adjusted by the particle size of the migrating particles and the pore size of the porous layer.
　本開示の一実施形態の表示装置および一実施形態の電子機器によれば、互いに平均粒径の異なる複数種類の泳動粒子と、互いに平均孔径が異なる複数の多孔質層とを用いることにより、泳動粒子の移動距離を泳動粒子の粒径および多孔質層の孔径によって調整するようにした。これにより、表示切り替えに要する時間を短縮することが可能となる。よって、表示品位を向上させつつ、多色表示が可能な表示装置および電子機器を提供することが可能となる。なお、ここに記載された効果は必ずしも限定されるものではなく、本開示中に記載されたいずれの効果であってもよい。 According to the display device of one embodiment of the present disclosure and the electronic apparatus of one embodiment, migration is performed by using a plurality of types of migrating particles having different average particle sizes and a plurality of porous layers having different average pore sizes. The moving distance of the particles was adjusted by the particle size of the migrating particles and the pore size of the porous layer. As a result, the time required for display switching can be shortened. Therefore, it is possible to provide a display device and an electronic device that can perform multicolor display while improving display quality. Note that the effects described here are not necessarily limited, and may be any effects described in the present disclosure.
本開示の一実施の形態に係る表示装置の構成を表す断面図である。It is sectional drawing showing the structure of the display apparatus which concerns on one embodiment of this indication. 図１に示した表示装置の平面図である。It is a top view of the display apparatus shown in FIG. 図１に示した電気泳動素子の動作を説明する模式図である。FIG. 2 is a schematic diagram for explaining the operation of the electrophoretic element shown in FIG. 1. 図１に示した電気泳動素子の動作を説明する模式図である。FIG. 2 is a schematic diagram for explaining the operation of the electrophoretic element shown in FIG. 1. 本開示の表示装置の動作を説明する模式図である。It is a schematic diagram explaining operation | movement of the display apparatus of this indication. 図１に示した表示装置におけるシアン表示を説明する概念図である。It is a conceptual diagram explaining the cyan display in the display apparatus shown in FIG. 図５Ａに示したシアン表示時における印加電圧の波形を説明する特性図である。It is a characteristic view explaining the waveform of the applied voltage at the time of the cyan display shown to FIG. 5A. 図１に示した表示装置におけるマゼンタ表示を説明する概念図である。It is a conceptual diagram explaining the magenta display in the display apparatus shown in FIG. 図６Ａに示したマゼンタ表示時における印加電圧の波形を説明する特性図である。FIG. 6B is a characteristic diagram illustrating a waveform of an applied voltage during magenta display illustrated in FIG. 6A. 図１に示した表示装置における黄色表示を説明する概念図である。It is a conceptual diagram explaining the yellow display in the display apparatus shown in FIG. 図７Ａに示した黄色表示時における印加電圧の波形を説明する特性図である。It is a characteristic view explaining the waveform of the applied voltage at the time of yellow display shown to FIG. 7A. 比較例としての表示装置における黄色表示を説明する概念図である。It is a conceptual diagram explaining the yellow display in the display apparatus as a comparative example. 図８Ａに示した黄色表示時における印加電圧の波形を説明する特性図である。It is a characteristic view explaining the waveform of the applied voltage at the time of yellow display shown to FIG. 8A. 本開示の変形例１に係る表示装置の構成を表す断面図である。14 is a cross-sectional view illustrating a configuration of a display device according to Modification 1 of the present disclosure. 図９に示した表示装置における白表示を説明する模式図である。It is a schematic diagram explaining the white display in the display apparatus shown in FIG. 図９に示した表示装置における黒表示を説明する模式図である。It is a schematic diagram explaining the black display in the display apparatus shown in FIG. 図９に示した表示装置における赤表示を説明する模式図である。It is a schematic diagram explaining the red display in the display apparatus shown in FIG. 本開示の変形例２に係る表示装置の構成を表す断面図である。14 is a cross-sectional view illustrating a configuration of a display device according to Modification 2 of the present disclosure. FIG. 図１１に示した表示装置の背面側の表示面側に対する電位差の時間変化を表す図である。It is a figure showing the time change of the electric potential difference with respect to the display surface side of the back side of the display apparatus shown in FIG. 図１２に示した電位差の時間変化による各泳動粒子の平均分布位置の時間変化を表す図である。It is a figure showing the time change of the average distribution position of each migrating particle by the time change of the electric potential difference shown in FIG. 一般的な表示装置の背面側の表示面側に対する電位差の時間変化を表す図である。It is a figure showing the time change of the electric potential difference with respect to the display surface side of the back side of a general display apparatus. 図１４に示した電位差の時間変化による各泳動粒子の平均分布位置の時間変化を表す図である。It is a figure showing the time change of the average distribution position of each migrating particle by the time change of the electric potential difference shown in FIG. 本開示の表示装置を用いた電子ブックの外観を表す斜視図である。It is a perspective view showing the external appearance of the electronic book using the display apparatus of this indication. 図１６Ａに示した電子ブックの他の例を表す斜視図である。FIG. 16B is a perspective view illustrating another example of the electronic book illustrated in FIG. 16A. 本開示の表示装置を用いたタブレットパーソナルコンピュータの外観を表す斜視図である。It is a perspective view showing the external appearance of the tablet personal computer using the display apparatus of this indication.
　以下、本開示における一実施形態について、図面を参照して詳細に説明する。なお、説明する順序は、下記の通りである。
１．実施の形態（複数種類の粒径を有する泳動粒子および複数種類の孔径を有する多孔質層を有する表示装置）
　１－１．電気泳動素子の構成
　１－２．表示装置の構成
　１－３．表示装置の好ましい表示方法
　１－４．作用・効果
２．変形例１（それぞれ帯電量の異なる複数種類の泳動粒子および複数種類の多孔質層を有する表示装置）
　２－１．電気泳動素子の構成
　２－２．作用・効果
３．変形例２（表示面側に光透過性を有すると共に、互いに孔径の異なる複数の多孔質層を積層した表示装置）
　３－１．電気泳動素子の構成
　３－２．作用・効果
４．適用例（電子機器） Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. The order of explanation is as follows.
1. Embodiment (display device having electrophoretic particles having a plurality of types of particle sizes and a porous layer having a plurality of types of pore sizes)
1-1. Configuration of electrophoretic element 1-2. Configuration of display device 1-3. Preferred display method of display device 1-4. Action / Effect Modification 1 (Display device having a plurality of types of migrating particles and a plurality of types of porous layers each having a different charge amount)
2-1. Configuration of electrophoretic element 2-2. Action and effect 3. Modification 2 (Display device in which a plurality of porous layers having light transmittance on the display surface side and different pore diameters are laminated)
3-1. Configuration of electrophoretic element 3-2. Action / effect 4. Application example (electronic equipment)
＜１．実施の形態＞
　図１は、本開示の一実施の形態の表示装置（表示装置１）の断面構成を表したものである。図２は、表示装置１を構成する電気泳動素子３０の平面構成を表したものである。表示装置１は、電気泳動現象を利用してコントラストを生じさせ、画像を表示する表示装置、例えば電子ペーパーディスプレイ等の多様な電子機器に適用されるものである。この表示装置１は、例えば、スペーサ３５を介して対向配置された駆動基板１０と対向基板２０との間に、電気泳動素子３０を含む表示層を備えたものである。電気泳動素子３０は、絶縁性液体３１中に、泳動粒子３２と複数の細孔３３３を有する多孔質層３３とを含んで構成されている。多孔質層３３は、繊維状構造体３３１およびこの繊維状構造体３３１に保持された非泳動粒子３３２を有する。なお、図１，２は電気泳動素子３０の構成を模式的に表したものであり、実際の寸法、形状とは異なる場合がある。 <1. Embodiment>
FIG. 1 illustrates a cross-sectional configuration of a display device (display device 1) according to an embodiment of the present disclosure. FIG. 2 shows a planar configuration of the electrophoretic element 30 constituting the display device 1. The display device 1 is applied to various electronic devices such as a display device that displays an image by using an electrophoretic phenomenon and displays an image, for example, an electronic paper display. The display device 1 includes, for example, a display layer including an electrophoretic element 30 between a drive substrate 10 and a counter substrate 20 that are disposed to face each other with a spacer 35 interposed therebetween. The electrophoretic element 30 includes an insulating liquid 31 including electrophoretic particles 32 and a porous layer 33 having a plurality of pores 333. The porous layer 33 has a fibrous structure 331 and non-migrating particles 332 held by the fibrous structure 331. 1 and 2 schematically show the configuration of the electrophoretic element 30 and may differ from actual dimensions and shapes.
（１－１．電気泳動素子の構成）
　本実施の形態では、泳動粒子３２は、複数種類の平均粒径を有し、多孔質層３３は、複数種類の平均孔径を有する層が積層された構成を有する。 (1-1. Configuration of electrophoretic element)
In the present embodiment, the migrating particles 32 have a plurality of types of average particle sizes, and the porous layer 33 has a configuration in which layers having a plurality of types of average pore sizes are stacked.
　絶縁性液体３１は、例えば、有機溶媒等の非水溶媒のいずれか１種類または２種類以上であり、具体的には、パラフィンまたはイソパラフィン等を含んで構成されている。この絶縁性液体３１の粘度および屈折率は、出来るだけ低いことが好ましい。泳動粒子３２の移動性（応答速度）が向上すると共に、それに応じて泳動粒子３２の移動に要するエネルギー（消費電力）が低くなるからである。また、絶縁性液体３１の屈折率と多孔質層３３の屈折率との差が大きくなり、多孔質層３３の光反射率が高くなるからである。なお、絶縁性液体３１の代わりに、微弱導電性液体を用いてもよい。 The insulating liquid 31 is, for example, one type or two or more types of non-aqueous solvents such as an organic solvent, and specifically includes paraffin or isoparaffin. It is preferable that the viscosity and refractive index of the insulating liquid 31 be as low as possible. This is because the mobility (response speed) of the migrating particles 32 is improved, and the energy (power consumption) required to move the migrating particles 32 is lowered accordingly. Further, the difference between the refractive index of the insulating liquid 31 and the refractive index of the porous layer 33 is increased, and the light reflectance of the porous layer 33 is increased. Note that a weak conductive liquid may be used instead of the insulating liquid 31.
　なお、絶縁性液体３１は、必要に応じて各種材料を含んでいてもよい。この材料は、例えば、着色剤、電荷制御剤、分散安定剤、粘度調整剤、界面活性剤または樹脂等である。 The insulating liquid 31 may contain various materials as necessary. This material is, for example, a colorant, a charge control agent, a dispersion stabilizer, a viscosity modifier, a surfactant or a resin.
　泳動粒子３２は、電気的に移動可能な１または２以上の荷電粒子であり、絶縁性液体３１中に分散されている。本実施の形態における泳動粒子３２は、上記のように、複数種類の平均粒径を有すると共に、各平均粒径ごとに１または２以上の荷電粒子で構成されている。具体的には、泳動粒子３２は、後述する多孔質層３３の積層数と同数の平均粒径の種類を有し、ここでは、例えば、互いに平均粒径の異なる４種類の泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄから構成されている。 The electrophoretic particles 32 are one or more charged particles that are electrically movable, and are dispersed in the insulating liquid 31. As described above, the migrating particles 32 in the present embodiment have a plurality of types of average particle diameters, and are composed of one or more charged particles for each average particle diameter. Specifically, the migrating particles 32 have the same number of types of average particle diameter as the number of porous layers 33 to be described later. Here, for example, four types of migrating particles 32A and 32B having different average particle diameters are used. , 32C, 32D.
　泳動粒子３２は、また、任意の光学的反射特性（光反射率）を有している。泳動粒子３２の光反射率は、特に限定されないが、少なくとも泳動粒子３２が多孔質層３３を遮蔽可能となるように設定されることが好ましい。泳動粒子３２の光反射率と多孔質層３３の光反射率との違いを利用してコントラストを生じさせるためである。本実施の形態では、泳動粒子３２を構成する４種類の泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄは、各平均粒径ごとに異なる色を有する。具体的には、例えば、シアン色（泳動粒子３２Ａ），マゼンタ色（泳動粒子３２Ｂ），黄色（泳動粒子３２Ｃ）および黒色（泳動粒子３２Ｄ）に着色されている。泳動粒子３２の粒径は、例えば、１００ｎｍ以上２μｍ以下の範囲であることが好ましく、泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄの平均粒径は、この範囲内で、例えば、１．２μｍ（泳動粒子３２Ａ），１μｍ（泳動粒子３２Ｂ），０．８μｍ（泳動粒子３２Ｃ），０．６μｍ（泳動粒子３２Ｄ）となっている。なお、各泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄの平均粒径は上記値に限定されるものではなく、例えば、小さい側の泳動粒子を平均粒径ａ1および粒径分散値σ1、大きい側の泳動粒子を平均粒径ａ2および粒径分散値σ2とした場合、ａ1－２σ1＞ａ2＋２σ2の関係であればよい。 The migrating particles 32 also have arbitrary optical reflection characteristics (light reflectivity). The light reflectance of the migrating particles 32 is not particularly limited, but is preferably set so that at least the migrating particles 32 can shield the porous layer 33. This is because contrast is generated by utilizing the difference between the light reflectance of the migrating particles 32 and the light reflectance of the porous layer 33. In the present embodiment, the four types of migrating particles 32A, 32B, 32C, and 32D constituting the migrating particle 32 have different colors for each average particle diameter. Specifically, for example, it is colored cyan (electrophoretic particles 32A), magenta (electrophoretic particles 32B), yellow (electrophoretic particles 32C), and black (electrophoretic particles 32D). The particle size of the migrating particles 32 is preferably in the range of, for example, 100 nm or more and 2 μm or less, and the average particle size of the migrating particles 32A, 32B, 32C, and 32D is, for example, 1.2 μm (electrophoretic particle 32A), 1 μm (electrophoretic particle 32B), 0.8 μm (electrophoretic particle 32C), and 0.6 μm (electrophoretic particle 32D). The average particle size of each migrating particle 32A, 32B, 32C, 32D is not limited to the above value. For example, the smaller migrating particle has an average particle size a 1 and a particle size dispersion value σ 1 and a larger side. If the electrophoretic particles and the average particle diameter a 2 and a particle size distribution value sigma 2, may be a relationship between a 1 -2σ 1> a 2 + 2σ 2.
　泳動粒子３２（３２Ａ，３２Ｂ，３２Ｃ，３２Ｄ）は、絶縁性液体３１中で画素電極１４と対向電極２２との間を移動可能になっている。泳動粒子３２は、例えば、有機顔料、無機顔料、染料、炭素材料、金属材料、金属酸化物、ガラスまたは高分子材料（樹脂）等のいずれか１種類または２種類以上の粒子（粉末）である。なお、泳動粒子３２は、上記した粒子を含む樹脂固形分の粉砕粒子またはカプセル粒子等でもよい。但し、炭素材料、金属材料、金属酸化物、ガラスまたは高分子材料に該当する材料は、有機顔料、無機顔料または染料に該当する材料から除かれることとする。 The migrating particles 32 (32A, 32B, 32C, 32D) can move between the pixel electrode 14 and the counter electrode 22 in the insulating liquid 31. The migrating particles 32 are, for example, one kind or two or more kinds of particles (powder) such as an organic pigment, an inorganic pigment, a dye, a carbon material, a metal material, a metal oxide, glass, or a polymer material (resin). . The migrating particles 32 may be pulverized particles or capsule particles of resin solids containing the above-described particles. However, materials corresponding to carbon materials, metal materials, metal oxides, glass, or polymer materials are excluded from materials corresponding to organic pigments, inorganic pigments, or dyes.
　有機顔料は、例えば、アゾ系顔料、メタルコンプレックスアゾ系顔料、ポリ縮合アゾ系顔料、フラバンスロン系顔料、ベンズイミダゾロン系顔料、フタロシアニン系顔料、キナクリドン系顔料、アントラキノン系顔料、ペリレン系顔料、ペリノン系顔料、アントラピリジン系顔料、ピランスロン系顔料、ジオキサジン系顔料、チオインジゴ系顔料、イソインドリノン系顔料、キノフタロン系顔料またはインダンスレン系顔料等である。無機顔料は、例えば、亜鉛華、アンチモン白、カーボンブラック、鉄黒、硼化チタン、ベンガラ、マピコエロー、鉛丹、カドミウムエロー、硫化亜鉛、リトポン、硫化バリウム、セレン化カドミウム、炭酸カルシウム、硫酸バリウム、クロム酸鉛、硫酸鉛、炭酸バリウム、鉛白またはアルミナホワイト等である。染料は、例えば、ニグロシン系染料、アゾ系染料、フタロシアニン系染料、キノフタロン系染料、アントラキノン系染料またはメチン系染料等である。炭素材料は、例えば、カーボンブラック等である。金属材料は、例えば、金、銀または銅等である。金属酸化物は、例えば、酸化チタン、酸化亜鉛、酸化ジルコニウム、チタン酸バリウム、チタン酸カリウム、銅－クロム酸化物、銅－マンガン酸化物、銅－鉄－マンガン酸化物、銅－クロム－マンガン酸化物または銅－鉄－クロム酸化物等である。高分子材料は、例えば、可視光領域に光吸収域を有する官能基が導入された高分子化合物等である。このように可視光領域に光吸収域を有する高分子化合物であれば、その種類は特に限定されない。 Organic pigments include, for example, azo pigments, metal complex azo pigments, polycondensed azo pigments, flavanthrone pigments, benzimidazolone pigments, phthalocyanine pigments, quinacridone pigments, anthraquinone pigments, perylene pigments, perinones. Pigments, anthrapyridine pigments, pyranthrone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments or indanthrene pigments. Inorganic pigments include, for example, zinc white, antimony white, carbon black, iron black, titanium boride, bengara, mapico yellow, red lead, cadmium yellow, zinc sulfide, lithopone, barium sulfide, cadmium selenide, calcium carbonate, barium sulfate, Lead chromate, lead sulfate, barium carbonate, lead white or alumina white. Examples of the dye include nigrosine dyes, azo dyes, phthalocyanine dyes, quinophthalone dyes, anthraquinone dyes, and methine dyes. The carbon material is, for example, carbon black. The metal material is, for example, gold, silver or copper. Examples of metal oxides include titanium oxide, zinc oxide, zirconium oxide, barium titanate, potassium titanate, copper-chromium oxide, copper-manganese oxide, copper-iron-manganese oxide, and copper-chromium-manganese oxide. Or copper-iron-chromium oxide. The polymer material is, for example, a polymer compound in which a functional group having a light absorption region in the visible light region is introduced. As long as the polymer compound has a light absorption region in the visible light region, the type of the compound is not particularly limited.
　泳動粒子３２（３２Ａ，３２Ｂ，３２Ｃ，３２Ｄ）の具体的な形成材料は、例えば、コントラストを生じさせるために泳動粒子３２が担う役割に応じてそれぞれ選択される。例えば、泳動粒子３２によって白表示がなされる場合の材料は、例えば、酸化チタン、酸化亜鉛、酸化ジルコニウム、チタン酸バリウムまたはチタン酸カリウム等の金属酸化物であり、中でも、酸化チタンが好ましい。電気化学的安定性および分散性等に優れていると共に、高い反射率が得られるからである。一方、泳動粒子３２により黒表示がなされる場合の材料は、例えば、炭素材料または金属酸化物等である。炭素材料は、例えば、カーボンブラック等であり、金属酸化物は、例えば、銅－クロム酸化物、銅－マンガン酸化物、銅－鉄－マンガン酸化物、銅－クロム－マンガン酸化物または銅－鉄－クロム酸化物等である。中でも、炭素材料が好ましい。優れた化学的安定性、移動性および光吸収性が得られるからである。 Specific materials for forming the migrating particles 32 (32A, 32B, 32C, and 32D) are selected according to, for example, the role that the migrating particles 32 play in order to cause contrast. For example, the material in which white display is performed by the migrating particles 32 is, for example, a metal oxide such as titanium oxide, zinc oxide, zirconium oxide, barium titanate or potassium titanate, and among these, titanium oxide is preferable. This is because it is excellent in electrochemical stability and dispersibility and has high reflectance. On the other hand, the material in the case where black display is performed by the migrating particles 32 is, for example, a carbon material or a metal oxide. The carbon material is, for example, carbon black, and the metal oxide is, for example, copper-chromium oxide, copper-manganese oxide, copper-iron-manganese oxide, copper-chromium-manganese oxide, or copper-iron. -Chromium oxide and the like. Among these, a carbon material is preferable. This is because excellent chemical stability, mobility and light absorption are obtained.
　本実施の形態では、上記のように泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄは、それぞれ、シアン色，マゼンタ色，黄色および黒色を呈する。このうち、黒色を呈する泳動粒子３２Ｄは、上記炭素材料や金属酸化物によって形成されている。シアン色を呈する泳動粒子３２Ａ，マゼンタ色を呈する泳動粒子３２Ｂおよび黄色を呈する泳動粒子３２Ｃは、それぞれ対応する色を呈する顔料を用いて形成することができる。具体的な材料としては、例えば、キナクリドン、ペリレン、ペリノン、イソインドリノン、ジオキサジン、イソインドリン、アントラキノン、キノフタロン、ジケトピロロピロール等の多環式顔料、フタロシアニン顔料、アゾイエロレーキ、アゾレーキレッド、ピアゾロン、ジスアゾ、モノアゾ、縮合アゾ、ナフトール、ペンズイミダゾロン等のアゾ顔料、カドミウムイエロー、ストロンチウムクロメート、ビリジアン、オキサイドクロミウム、コバルト青、ウルトラマリン等の無機顔料が挙げられる。 In the present embodiment, as described above, the migrating particles 32A, 32B, 32C, and 32D exhibit cyan, magenta, yellow, and black, respectively. Among these, the electrophoretic particles 32D exhibiting black are formed of the carbon material or the metal oxide. The migrating particles 32A exhibiting a cyan color, the migrating particles 32B exhibiting a magenta color, and the migrating particles 32C exhibiting a yellow color can be formed using pigments exhibiting corresponding colors. Specific materials include, for example, quinacridone, perylene, perinone, isoindolinone, dioxazine, isoindoline, anthraquinone, quinophthalone, diketopyrrolopyrrole, and other polycyclic pigments, phthalocyanine pigments, azo lake red, azo lake red, piazolone, Examples thereof include azo pigments such as disazo, monoazo, condensed azo, naphthol, and pendimidazolone, and inorganic pigments such as cadmium yellow, strontium chromate, viridian, oxide chromium, cobalt blue, and ultramarine.
　絶縁性液体３１中における泳動粒子３２（３２Ａ，３２Ｂ，３２Ｃ，３２Ｄ）の含有量（濃度）は、特に限定されないが、泳動粒子３２全体では、例えば、０．１重量％～１０重量％であることが好ましい。泳動粒子３２による多孔質層３３の遮蔽性、多孔質層３３による泳動粒子３２の隠蔽性および移動性が確保されるからである。０．１重量％よりも少ないと、泳動粒子３２が多孔質層３３を遮蔽しにくくなる可能性がある。一方、１０重量％よりも多いと、泳動粒子３２の分散性が低下するため、泳動粒子３２が泳動しにくくなり、場合によっては凝集する可能性がある。各色に着色された泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄとしては、粒径にもよるが、例えば、最も粒径の大きな泳動粒子３２Ａでは、０．１重量％～４重量％、次に大きな泳動粒子３２Ｂでは、０．１重量％～４重量％、その次に大きな泳動粒子３２Ｃでは、０．１重量％～４重量％、最も小さな泳動粒子３２Ｄでは、０．１重量％～４重量％であることが好ましい。ただし、最適な重量％は期待する表示特性、色域、コントラストによってそれぞれの粒子の重量比率を適宜調整することが望ましい。 The content (concentration) of the migrating particles 32 (32A, 32B, 32C, and 32D) in the insulating liquid 31 is not particularly limited, but the entire migrating particles 32 are, for example, 0.1 wt% to 10 wt%. It is preferable. This is because the shielding property of the porous layer 33 by the migrating particles 32 and the concealing property and mobility of the migrating particles 32 by the porous layer 33 are ensured. If the amount is less than 0.1% by weight, the migrating particles 32 may hardly shield the porous layer 33. On the other hand, when the amount is more than 10% by weight, the dispersibility of the migrating particles 32 is lowered, so that the migrating particles 32 are difficult to migrate and may be aggregated in some cases. Depending on the particle size, the electrophoretic particles 32A, 32B, 32C, and 32D colored in the respective colors may be, for example, 0.1% by weight to 4% by weight for the electrophoretic particle 32A having the largest particle size, and the next largest electrophoretic particle For particles 32B, 0.1% to 4% by weight, for the next larger migrating particles 32C, 0.1% to 4% by weight, and for the smallest migrating particles 32D, 0.1% to 4% by weight. Preferably there is. However, it is desirable to adjust the weight ratio of each particle appropriately depending on the expected display characteristics, color gamut, and contrast.
　なお、泳動粒子３２は、絶縁性液体３１中で長期間にわたって分散および帯電しやすいと共に、多孔質層３３に吸着されにくいことが好ましい。このため、静電反発により泳動粒子３２を分散させるために分散剤（または電荷調整剤）を用いたり、泳動粒子３２に表面処理を施してもよく、両者を併用してもよい。 In addition, it is preferable that the migrating particles 32 are easily dispersed and charged in the insulating liquid 31 for a long period of time and are not easily adsorbed by the porous layer 33. For this reason, in order to disperse the electrophoretic particles 32 by electrostatic repulsion, a dispersant (or a charge adjusting agent) may be used, or the electrophoretic particles 32 may be subjected to a surface treatment, or both may be used in combination.
　分散剤は、例えばLubrizol社製のSolsperseシリーズ、BYK-Chemie社製のBYK シリーズまたはAnti-Terra シリーズ、あるいはICI Americas 社製Spanシリーズ等である。 The dispersing agent is, for example, Solsperse series manufactured by Lubrizol, BYK® series or Anti-Terra® series manufactured by BYK-Chemie, or Span series manufactured by ICI® Americas®.
　表面処理は、例えば、ロジン処理、界面活性剤処理、顔料誘導体処理、カップリング剤処理、グラフト重合処理またはマイクロカプセル化処理等である。中でも、グラフト重合処理、マイクロカプセル化処理またはそれらの組み合わせが好ましい。長期間の分散安定性等が得られるからである。 The surface treatment is, for example, rosin treatment, surfactant treatment, pigment derivative treatment, coupling agent treatment, graft polymerization treatment or microencapsulation treatment. Among these, graft polymerization treatment, microencapsulation treatment, or a combination thereof is preferable. This is because long-term dispersion stability and the like can be obtained.
　表面処理用の材料は、例えば、泳動粒子３２の表面に吸着可能な官能基と重合性官能基とを有する材料（吸着材料）等である。吸着可能な官能基の種類は、泳動粒子３２の形成材料に応じて決定される。一例を挙げると、カーボンブラック等の炭素材料に対しては４－ビニルアニリン等のアニリン誘導体であり、金属酸化物に対してはメタクリル酸３－（トリメトキシシリル）プロピル等のオルガノシラン誘導体である。重合性官能基は、例えば、ビニル基、アクリル基、メタクリル基等である。 The surface treatment material is, for example, a material (adsorbing material) having a functional group and a polymerizable functional group that can be adsorbed on the surface of the migrating particle 32. The type of functional group that can be adsorbed is determined according to the material for forming the migrating particles 32. For example, carbon materials such as carbon black are aniline derivatives such as 4-vinylaniline, and metal oxides are organosilane derivatives such as 3- (trimethoxysilyl) propyl methacrylate. . Examples of the polymerizable functional group include a vinyl group, an acrylic group, and a methacryl group.
　また、表面処理用の材料は、例えば、重合性官能基が導入された泳動粒子３２の表面にグラフト可能な材料（グラフト性材料）である。このグラフト性材料は、重合性官能基と、絶縁性液体３１中に分散可能であると共に、立体障害により分散性を保持可能な分散用官能基とを有していることが好ましい。重合性官能基の種類は、吸着性材料について説明した場合と同様である。分散用官能基は、例えば、絶縁性液体３１がパラフィンである場合には分岐状のアルキル基等である。グラフト性材料を重合およびグラフトさせるためには、例えばアゾビスイソブチロニトリル（ＡＩＢＮ）等の重合開始剤を用いればよい。 Further, the material for surface treatment is, for example, a material (graftable material) that can be grafted on the surface of the migrating particles 32 into which a polymerizable functional group is introduced. The graft material preferably has a polymerizable functional group and a dispersing functional group that can be dispersed in the insulating liquid 31 and can maintain dispersibility due to steric hindrance. The kind of polymerizable functional group is the same as that described for the adsorptive material. The dispersing functional group is, for example, a branched alkyl group when the insulating liquid 31 is paraffin. In order to polymerize and graft the graft material, for example, a polymerization initiator such as azobisisobutyronitrile (AIBN) may be used.
　参考までに、上記のように絶縁性液体３１中に泳動粒子３２を分散させる方法の詳細については、「超微粒子の分散技術とその評価～表面処理・微粉砕と気中／液中／高分子中の分散安定化～（サイエンス＆テクノロジー社）」等の書籍に掲載されている。 For reference, the details of the method for dispersing the migrating particles 32 in the insulating liquid 31 as described above are described in “Dispersion technology of ultrafine particles and its evaluation—surface treatment / fine pulverization and air / liquid / polymer. It is published in books such as “Dispersion Stabilization ~ (Science & Technology)”.
　多孔質層３３は、例えば、図２に示したように、繊維状構造体３３１により形成された３次元立体構造物（不織布のような不規則なネットワーク構造物）である。この多孔質層３３は、繊維状構造体３３１が存在していない箇所に、泳動粒子３２が通過するための複数の隙間（細孔３３３）を有している。なお、図１では、多孔質層３３の図示を簡略化している。 The porous layer 33 is, for example, a three-dimensional structure (irregular network structure such as a nonwoven fabric) formed by a fibrous structure 331 as shown in FIG. The porous layer 33 has a plurality of gaps (pores 333) through which the migrating particles 32 pass in places where the fibrous structure 331 does not exist. In FIG. 1, the illustration of the porous layer 33 is simplified.
　繊維状構造体３３１は、繊維径（直径）に対して長さが十分に大きい繊維状物質である。繊維状構造体３３１の形状（外観）は、上記のように繊維径に対して長さが十分に大きい繊維状であれば、特に限定されない。具体的には、直線状でもよいし、縮れていたり、途中で折れ曲がっていてもよい。また、一方向に延在しているだけに限らず、途中で１または２以上の方向に分岐していてもよい。この繊維状構造体３３１の形成方法は、特に限定されないが、例えば、相分離法、相反転法、静電（電界）紡糸法、溶融紡糸法、湿式紡糸法、乾式紡糸法、ゲル紡糸法、ゾルゲル法またはスプレー塗布法等であることが好ましい。繊維径に対して長さが十分に大きい繊維状物質を容易且つ安定に形成しやすいからである。 The fibrous structure 331 is a fibrous substance having a sufficiently large length with respect to the fiber diameter (diameter). The shape (external appearance) of the fibrous structure 331 is not particularly limited as long as the fibrous structure 331 has a fibrous shape that is sufficiently long with respect to the fiber diameter as described above. Specifically, it may be linear, may be curled, or may be bent in the middle. Moreover, you may branch to 1 or 2 or more directions on the way, not only extending in one direction. The formation method of the fibrous structure 331 is not particularly limited. For example, a phase separation method, a phase inversion method, an electrostatic (electric field) spinning method, a melt spinning method, a wet spinning method, a dry spinning method, a gel spinning method, A sol-gel method or a spray coating method is preferred. This is because a fibrous material having a sufficiently large length with respect to the fiber diameter can be easily and stably formed.
　繊維状構造体３３１の平均繊維径は、特に限定されないが、できるだけ小さいことが好ましい。光が乱反射しやすくなると共に、細孔３３３の平均孔径が大きくなるからである。但し、平均繊維径は、繊維状構造体３３１が非泳動粒子３３２を保持できるように決定されることが好ましい。このため、繊維状構造体３３１の平均繊維径は、１０μｍ以下であることが好ましい。なお、平均繊維径の下限は、特に限定されないが、例えば、０．１μｍであり、それ以下でもよい。この平均繊維径は、例えば、走査型電子顕微鏡（ＳＥＭ）等を用いた顕微鏡観察により測定される。なお、繊維状構造体３３１の平均長さは、任意でよい。 The average fiber diameter of the fibrous structure 331 is not particularly limited, but is preferably as small as possible. This is because light easily diffuses and the average pore diameter of the pores 333 increases. However, the average fiber diameter is preferably determined so that the fibrous structure 331 can hold the non-migrating particles 332. For this reason, it is preferable that the average fiber diameter of the fibrous structure 331 is 10 micrometers or less. In addition, although the minimum of an average fiber diameter is not specifically limited, For example, it is 0.1 micrometer and may be less than that. This average fiber diameter is measured, for example, by microscopic observation using a scanning electron microscope (SEM) or the like. Note that the average length of the fibrous structure 331 may be arbitrary.
　繊維状構造体３３１には、１または２以上の非泳動粒子３３２が含まれており、その非泳動粒子３３２は、繊維状構造体３３１により保持されている。３次元立体構造物である多孔質層３３では、１本の繊維状構造体３３１がランダムに絡み合っていてもよいし、複数本の繊維状構造体３３１が集合してランダムに重なっていてもよいし、両者が混在していてもよい。繊維状構造体３３１が複数本である場合、各繊維状構造体３３１は、１または２以上の非泳動粒子３３２を保持していることが好ましい。なお、図２では、複数本の繊維状構造体３３１により多孔質層３３が形成されている場合を示している。 The fibrous structure 331 includes one or more non-migrating particles 332, and the non-migrating particles 332 are held by the fibrous structure 331. In the porous layer 33 which is a three-dimensional structure, one fibrous structure 331 may be entangled at random, or a plurality of fibrous structures 331 may be gathered and overlap at random. However, both may be mixed. When there are a plurality of fibrous structures 331, each fibrous structure 331 preferably holds one or more non-migrating particles 332. FIG. 2 shows a case where the porous layer 33 is formed by a plurality of fibrous structures 331.
　多孔質層３３が３次元立体構造物であるのは、その不規則な立体構造により外光が乱反射（多重散乱）されやすいため、多孔質層３３の光反射率が高くなると共に、その高い光反射率を得るために多孔質層３３が薄くて済むからである。これにより、コントラストが高くなると共に、泳動粒子３２を移動させるために必要なエネルギーが低くなる。また、細孔３３３の平均孔径が大きくなると共に、その数が多くなるため、泳動粒子３２が細孔３３３を通過しやすくなるからである。これにより、泳動粒子３２の移動に要する時間が短くなると共に、その泳動粒子３２の移動に要するエネルギーも低くなる。 The reason why the porous layer 33 is a three-dimensional structure is that the irregular three-dimensional structure easily causes external light to be irregularly reflected (multiple scattering), so that the light reflectance of the porous layer 33 increases and the high light This is because the porous layer 33 can be thin in order to obtain the reflectance. As a result, the contrast increases and the energy required to move the migrating particles 32 decreases. In addition, since the average pore diameter of the pores 333 is increased and the number thereof is increased, the migrating particles 32 can easily pass through the pores 333. As a result, the time required to move the migrating particles 32 is shortened, and the energy required to move the migrating particles 32 is also reduced.
　繊維状構造体３３１に非泳動粒子３３２が含まれているのは、非泳動粒子３３２によって外光が乱反射されやすくなり、多孔質層３３の光反射率がより高くなるからである。これにより、コントラストがより高くなる。 The reason why the non-migrating particles 332 are included in the fibrous structure 331 is that the non-migrating particles 332 are likely to cause irregular reflection of external light, and the light reflectance of the porous layer 33 becomes higher. Thereby, contrast becomes higher.
　本実施の形態では、多孔質層３３は、上記のように、細孔３３３の平均孔径がそれぞれ異なる複数の層によって構成されている。具体的には、多孔質層３３は、泳動粒子３２の平均粒径の種類と同数、即ち、泳動粒子３２が呈する色の数と同数の層が積層された多層構造を有しており、ここでは、互いに平均孔径が異なる４種類の層（多孔質層３３Ａ，３３Ｂ，３３Ｃ，３３Ｄ）が積層された構成を有する。これら４種類の多孔質層３３Ａ，３３Ｂ，３３Ｃ，３３Ｄは、表示面Ｓ１側から背面Ｓ２側に向けて平均孔径が小さくなるように積層されている。 In the present embodiment, the porous layer 33 is constituted by a plurality of layers having different average pore diameters of the pores 333 as described above. Specifically, the porous layer 33 has a multilayer structure in which the same number of types of the average particle diameters of the migrating particles 32, that is, the same number of colors as the migrating particles 32 are laminated. Then, it has a configuration in which four types of layers ( porous layers 33A, 33B, 33C, 33D) having different average pore diameters are laminated. These four types of porous layers 33A, 33B, 33C, and 33D are laminated so that the average pore diameter decreases from the display surface S1 side to the back surface S2 side.
　多孔質層３３の孔径は、特に限定されないが、一般的に、できるだけ大きいことが好ましい。泳動粒子３２が細孔３３３を通過しやすくなるからである。但し、本実施の形態では、各多孔質層３３Ａ，３３Ｂ，３３Ｃ，３３Ｄの孔径は、上述した泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄの粒径によって決定される。具体的には、図４の模式図に示したように、多孔質層３３Ａは、全ての泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄが通過できる孔径であることが好ましく、その平均孔径は、例えば、１００ｎｍ以上５μｍ以下の範囲であることが好ましい。多孔質層３３Ｂは、泳動粒子３２Ａ以外の泳動粒子３２Ｂ，３２Ｃ，３２Ｄが通過できる孔径であることが好ましく、その平均孔径は、例えば、１．１１μｍ以上１．３μｍ以下の範囲であることが好ましい。多孔質層３３Ｃは、泳動粒子３２Ａ，３２Ｂ以外の泳動粒子３２Ｃ，３２Ｄが通過できる孔径であることが好ましく、その平均孔径は、例えば、０．９１μｍ以上１．１μｍ以下の範囲であることが好ましい。多孔質層３３Ｄは、泳動粒子３２Ｄのみが通過できる孔径であればよく、その孔径は、例えば、０．７１μｍ以上０．９μｍ以下の範囲であることが好ましい。これにより、泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄの駆動基板１０と対向基板２０との間における移動距離が制御される。 The pore diameter of the porous layer 33 is not particularly limited, but is generally preferably as large as possible. This is because the migrating particles 32 easily pass through the pores 333. However, in the present embodiment, the pore diameters of the porous layers 33A, 33B, 33C, and 33D are determined by the particle diameters of the migrating particles 32A, 32B, 32C, and 32D described above. Specifically, as shown in the schematic diagram of FIG. 4, the porous layer 33A preferably has a pore diameter through which all the migrating particles 32A, 32B, 32C, and 32D can pass, and the average pore diameter is, for example, It is preferably in the range of 100 nm to 5 μm. The porous layer 33B preferably has a pore diameter through which the migrating particles 32B, 32C, and 32D other than the migrating particle 32A can pass, and the average pore diameter is preferably in the range of, for example, 1.11 μm to 1.3 μm. . The porous layer 33C preferably has a pore diameter through which the migrating particles 32C and 32D other than the migrating particles 32A and 32B can pass, and the average pore diameter is preferably in the range of 0.91 μm to 1.1 μm, for example. . The porous layer 33D has only to have a pore size through which only the migrating particles 32D can pass, and the pore size is preferably in the range of 0.71 μm to 0.9 μm, for example. Thereby, the moving distance between the driving substrate 10 and the counter substrate 20 of the migrating particles 32A, 32B, 32C, and 32D is controlled.
　多孔質層３３Ａ，３３Ｂ，３３Ｃ，３３Ｄの厚みは、特に限定されないが、例えば、多孔質層３３全体では、５μｍ～１００μｍであることが好ましい。多孔質層３３の隠蔽性が高くなると共に、泳動粒子３２が細孔３３３を通過しやすくなるからである。なお、少なくも最も表示面側に配設される多孔質層３３Ａの厚みは、少なくとも、最も孔径が大きな泳動粒子３２Ａが背面Ｓ２側に移動した際に、泳動粒子３２Ａを隠蔽できる厚みであることが好ましい。また、多孔質層３３Ａ，３３Ｂ，３３Ｃ，３３Ｄは、上記範囲内であれば、全ての層が同程度の厚みとしてもよいが、表示切り替えに要する時間を考慮すると、泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄの移動距離は短い方が好ましい。これらのことから、多孔質層３３Ａ，３３Ｂ，３３Ｃ，３３Ｄの厚みは、それぞれ、以下の範囲とすることが好ましい。多孔質層３３Ａの厚みは、例えば、１０μｍ以上３０μｍ以下であることが好ましく、多孔質層３３Ｂの厚みは、例えば、２μｍ以上１５μｍ以下であることが好ましく、多孔質層３３Ｃの厚みは、例えば、２μｍ以上１５μｍ以下であることが好ましく、多孔質層３３Ｄの厚みは、例えば、２μｍ以上１５μｍ以下であることが好ましい。 The thickness of the porous layers 33A, 33B, 33C, and 33D is not particularly limited. For example, the entire porous layer 33 is preferably 5 μm to 100 μm. This is because the concealability of the porous layer 33 is enhanced, and the migrating particles 32 can easily pass through the pores 333. Note that at least the thickness of the porous layer 33A disposed on the display surface side is at least a thickness capable of concealing the electrophoretic particles 32A when the electrophoretic particles 32A having the largest pore diameter move to the back surface S2. Is preferred. In addition, the porous layers 33A, 33B, 33C, and 33D may have the same thickness as long as they are within the above range, but considering the time required for display switching, the migrating particles 32A, 32B, and 32C The moving distance of 32D is preferably shorter. For these reasons, the thicknesses of the porous layers 33A, 33B, 33C, and 33D are preferably set in the following ranges, respectively. The thickness of the porous layer 33A is preferably, for example, 10 μm or more and 30 μm or less, the thickness of the porous layer 33B is, for example, preferably 2 μm or more and 15 μm or less, and the thickness of the porous layer 33C is, for example, The thickness is preferably 2 μm or more and 15 μm or less, and the thickness of the porous layer 33D is preferably, for example, 2 μm or more and 15 μm or less.
　繊維状構造体３３１は、例えば、アクリル樹脂等の高分子材料または無機材料等のいずれか１種類または２種類以上を含んで形成されており、他の材料を含んでいてもよい。高分子材料としては、例えば、ナイロン、ポリ乳酸、ポリアミド、ポリイミド、ポリエチレンテレフタレート、ポリアクリロニトリル、ポリエチレンオキシド、ポリビニルカルバゾール、ポリビニルクロライド、ポリウレタン、ポリスチレン、ポリビニルアルコール、ポリサルフォン、ポリビニルピロリドン、ポリビニリデンフロリド、ポリヘキサフルオロプロピレン、セルロースアセテート、コラーゲン、ゼラチン、キトサンまたはそれらのコポリマー等が挙げられる。無機材料としては、例えば、酸化チタン挙げられる。中でも、繊維状構造体３３１の形成材料としては、高分子材料が好ましい。反応性（光反応性等）が低い、即ち、化学的に安定であるため、繊維状構造体３３１の意図しない分解反応が抑制されるからである。なお、繊維状構造体３３１が高反応性の材料により形成されている場合には、その繊維状構造体３３１の表面は任意の保護層により被覆されていることが好ましい。 The fibrous structure 331 is formed including any one type or two or more types of polymer materials such as acrylic resins or inorganic materials, for example, and may include other materials. Examples of the polymer material include nylon, polylactic acid, polyamide, polyimide, polyethylene terephthalate, polyacrylonitrile, polyethylene oxide, polyvinyl carbazole, polyvinyl chloride, polyurethane, polystyrene, polyvinyl alcohol, polysulfone, polyvinyl pyrrolidone, polyvinylidene fluoride, poly Examples thereof include hexafluoropropylene, cellulose acetate, collagen, gelatin, chitosan, and copolymers thereof. Examples of the inorganic material include titanium oxide. Among these, a polymer material is preferable as a material for forming the fibrous structure 331. This is because the reactivity (photoreactivity, etc.) is low, that is, because it is chemically stable, the unintended decomposition reaction of the fibrous structure 331 is suppressed. Note that in the case where the fibrous structure 331 is formed of a highly reactive material, the surface of the fibrous structure 331 is preferably covered with an arbitrary protective layer.
　特に、繊維状構造体３３１は、ナノファイバーであることが好ましい。立体構造が複雑化して外光を乱反射しやすくなるため、多孔質層３３の光反射率がより高くなると共に、多孔質層３３の単位体積中に占める細孔３３３の体積の割合が大きくなるため、泳動粒子３２が細孔３３３を通過しやすくなるからである。これにより、コントラストがより高くなると共に、泳動粒子３２の移動に要するエネルギーがより低くなる。ナノファイバーとは、繊維径が０．００１μｍ～０．１μｍであると共に、長さが繊維径の１００倍以上である繊維状物質である。ナノファイバーである繊維状構造体３３１は、高分子材料を用いて静電紡糸法により形成されていることが好ましい。繊維径が小さい繊維状構造体３３１を容易且つ安定に形成しやすいからである。 In particular, the fibrous structure 331 is preferably a nanofiber. Since the three-dimensional structure is complicated and it becomes easy to diffusely reflect external light, the light reflectance of the porous layer 33 is further increased, and the volume ratio of the pores 333 in the unit volume of the porous layer 33 is increased. This is because the migrating particles 32 can easily pass through the pores 333. Thereby, the contrast becomes higher and the energy required to move the migrating particles 32 becomes lower. Nanofiber is a fibrous substance having a fiber diameter of 0.001 μm to 0.1 μm and a length that is 100 times or more of the fiber diameter. The fibrous structure 331 that is a nanofiber is preferably formed by an electrospinning method using a polymer material. This is because the fibrous structure 331 having a small fiber diameter can be easily and stably formed.
　繊維状構造体３３１は、泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄとは異なる光学的反射特性を有していることが好ましい。具体的には、繊維状構造体３３１の光反射率は、特に限定されないが、少なくとも多孔質層３３が全体として泳動粒子３２を遮蔽可能となるように設定されることが好ましい。上記のように、泳動粒子３２の光反射率と多孔質層３３の光反射率との違いを利用してコントラストを生じさせるためである。これに伴い、絶縁性液体３１中で光透過性（無色透明）を有する繊維状構造体３３１は好ましくない。但し、繊維状構造体３３１の光反射率が多孔質層３３全体の光反射率にほとんど影響を及ぼさず、その多孔質層３３全体の光反射率が実質的に非泳動粒子３３２の光反射率により決定される場合には、繊維状構造体３３１の光反射率は任意でよい。 It is preferable that the fibrous structure 331 has an optical reflection characteristic different from that of the migrating particles 32A, 32B, 32C, and 32D. Specifically, the light reflectance of the fibrous structure 331 is not particularly limited, but is preferably set so that at least the porous layer 33 can shield the migrating particles 32 as a whole. This is because the contrast is generated by utilizing the difference between the light reflectance of the migrating particles 32 and the light reflectance of the porous layer 33 as described above. Accordingly, the fibrous structure 331 having light transparency (colorless and transparent) in the insulating liquid 31 is not preferable. However, the light reflectivity of the fibrous structure 331 hardly affects the light reflectivity of the entire porous layer 33, and the light reflectivity of the entire porous layer 33 is substantially the light reflectivity of the non-migrating particles 332. , The light reflectance of the fibrous structure 331 may be arbitrary.
　非泳動粒子３３２は、繊維状構造体３３１に固定されており、電気的に泳動しない粒子である。この非泳動粒子３３２の形成材料は、例えば、泳動粒子３２の形成材料と同様であり、後述するように、非泳動粒子３３２が担う役割に応じて選択される。 Non-electrophoretic particles 332 are particles that are fixed to the fibrous structure 331 and do not migrate electrically. The material for forming the non-electrophoretic particles 332 is, for example, the same as the material for forming the electrophoretic particles 32, and is selected according to the role played by the non-electrophoretic particles 332 as described later.
　なお、非泳動粒子３３２は、繊維状構造体３３１により保持されていれば、繊維状構造体３３１から部分的に露出していてもよいし、内部に埋設されていてもよい。 In addition, as long as the non-migrating particle 332 is held by the fibrous structure 331, the non-migrating particle 332 may be partially exposed from the fibrous structure 331 or embedded therein.
　非泳動粒子３３２は、泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄとは異なる光学的反射特性を有している。非泳動粒子３３２の光反射率は、特に限定されないが、少なくとも多孔質層３３が全体として泳動粒子３２を遮蔽可能となるように設定されることが好ましい。上記のように、泳動粒子３２の光反射率と多孔質層３３の光反射率との違いを利用してコントラストを表示させるためである。 The non-migrating particles 332 have optical reflection characteristics different from those of the migrating particles 32A, 32B, 32C, and 32D. The light reflectance of the non-migrating particles 332 is not particularly limited, but is preferably set so that at least the porous layer 33 can shield the migrating particles 32 as a whole. This is because the contrast is displayed using the difference between the light reflectance of the migrating particles 32 and the light reflectance of the porous layer 33 as described above.
　ここで、非泳動粒子３３２の具体的な形成材料は、例えば、コントラストを生じさせるために非泳動粒子３３２が担う役割に応じて選択される。具体的には、泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄが、それぞれ、シアン，マゼンタ，黄および黒の４色表示を担う場合には、非泳動粒子３３２は、例えば、白表示を担うことが好ましい。この場合には、上記泳動粒子３２が白表示を行う場合に挙げた材料を用いることが好ましい。具体的には、金属酸化物が好ましく、酸化チタンがより好ましい。電気化学的安定性および定着性等に優れていると共に、高い反射率が得られるからである。コントラストを生じさせることができれば、非泳動粒子３３２の形成材料は、泳動粒子３２の形成材料と同じ材料でもよいし、違う材料でもよい。 Here, the specific forming material of the non-migrating particles 332 is selected according to the role played by the non-migrating particles 332 in order to generate contrast, for example. Specifically, when the migrating particles 32A, 32B, 32C, and 32D are responsible for four-color display of cyan, magenta, yellow, and black, respectively, the non-migrating particles 332 are preferably responsible for white display, for example. . In this case, it is preferable to use the materials mentioned when the electrophoretic particles 32 perform white display. Specifically, a metal oxide is preferable and titanium oxide is more preferable. This is because it is excellent in electrochemical stability and fixability, and high reflectance can be obtained. As long as a contrast can be generated, the material for forming the non-migrating particles 332 may be the same material as the material for forming the migrating particles 32 or may be a different material.
　スペーサ３５は、例えば、高分子材料等の絶縁性材料を含んで構成されている。但し、スペーサ３５の構成は、特に限定されず、微粒子が混入されたシール材等でもよい。 The spacer 35 includes, for example, an insulating material such as a polymer material. However, the configuration of the spacer 35 is not particularly limited, and may be a sealing material mixed with fine particles.
　スペーサ３５の形状は、特に限定されないが、泳動粒子３２の画素電極１４および対向電極２２間の移動を妨げないと共に、それを均一分布させることができる形状であることが好ましく、例えば、格子状である。また、スペーサ３５の厚さ（例えば、多孔質層３３Ａ，３３Ｂ，３３Ｃ，３３Ｄの積層方向）は、特に限定されないが、中でも、消費電力を低くするためにできるだけ薄いことが好ましく、例えば、１０μｍ～１００μｍである。なお、図１では、スペーサ３５の構成を簡略化して示している。 The shape of the spacer 35 is not particularly limited, but is preferably a shape that does not hinder the movement of the migrating particles 32 between the pixel electrode 14 and the counter electrode 22 and that can be uniformly distributed. is there. Further, the thickness of the spacer 35 (for example, the stacking direction of the porous layers 33A, 33B, 33C, and 33D) is not particularly limited, but in particular, it is preferably as thin as possible in order to reduce power consumption. 100 μm. In addition, in FIG. 1, the structure of the spacer 35 is simplified and shown.
（１－２．表示装置の構成）
　表示装置１は、上記のように、スペーサ３５を介して一対の基板、駆動基板１０と対向基板２０とが対向配置されており、その間に表示層を備えたものである。 (1-2. Configuration of display device)
As described above, the display device 1 includes a pair of substrates, the drive substrate 10 and the counter substrate 20 that are opposed to each other with the spacer 35 interposed therebetween, and includes a display layer therebetween.
　駆動基板１０は、例えば、支持部材１１の一面に、薄膜トランジスタ（ＴＦＴ）１２、保護層１３および画素電極１４がこの順に積層されたものである。ＴＦＴ１２および画素電極１４は、例えば、アクティブマトリクス方式の駆動回路を構築するために、画素配置に応じてマトリクス状に分割形成されている。 The driving substrate 10 is, for example, one in which a thin film transistor (TFT) 12, a protective layer 13, and a pixel electrode 14 are laminated in this order on one surface of a support member 11. The TFT 12 and the pixel electrode 14 are divided and formed in a matrix according to the pixel arrangement, for example, in order to construct an active matrix drive circuit.
　支持部材１１は、例えば、無機材料、金属材料またはプラスチック材料等のいずれか１種類または２種類以上により形成されている。無機材料としては、例えば、ケイ素（Ｓｉ）、酸化ケイ素（ＳｉＯx）、窒化ケイ素（ＳｉＮx）または酸化アルミニウム（ＡｌＯx）等が挙げられる。酸化ケイ素には、例えば、ガラスまたはスピンオングラス（ＳＯＧ）等が含まれる。金属材料としては、例えば、アルミニウム（Ａｌ）、ニッケル（Ｎｉ）またはステンレス等が挙げられる。プラスチック材料としては、例えば、ポリカーボネート（ＰＣ）、ポリエチレンテレフタレート（ＰＥＴ）、ポリエチレンナフタレート（ＰＥＮ）、ポリエチルエーテルケトン（ＰＥＥＫ）、シクロオレフィンポリマー（ＣＯＰ）、ポリイミド（ＰＩ）またはポリエーテルサルフォン（ＰＥＳ）等が挙げられる。 The support member 11 is formed of, for example, one or more of inorganic materials, metal materials, plastic materials, and the like. Examples of the inorganic material include silicon (Si), silicon oxide (SiO x ), silicon nitride (SiN x ), and aluminum oxide (AlO x ). Silicon oxide includes, for example, glass or spin-on-glass (SOG). Examples of the metal material include aluminum (Al), nickel (Ni), and stainless steel. Examples of the plastic material include polycarbonate (PC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethyl ether ketone (PEEK), cycloolefin polymer (COP), polyimide (PI), and polyether sulfone (PES). ) And the like.
　支持部材１１は、光透過性であってもよいし、非光透過性であってもよい。また、支持部材１１は、ウェハ等の剛性を有する基板であってもよいし、可撓性を有する薄層ガラスまたはフィルム等であってもよい。但し、フレキシブル（折り曲げ可能）な電子ペーパーディスプレイを実現できることから、可撓性を有する材料からなることが望ましい。 The support member 11 may be light transmissive or non-light transmissive. The support member 11 may be a rigid substrate such as a wafer, or may be a flexible thin glass or film. However, since a flexible (foldable) electronic paper display can be realized, it is desirable to be made of a flexible material.
　ＴＦＴ１２は、画素を選択するためのスイッチング用素子である。ＴＦＴ１２は、例えば、チャネル層（活性層）として、アモルファスシリコン、ポリシリコンまたは酸化物等の無機半導体層を用いた無機ＴＦＴでもよいし、ペンタセン等の有機半導体層を用いた有機ＴＦＴでもよい。ＴＦＴ１２は、例えば、保護層１３によって被覆されている。保護層１３上には、更に、例えばポリイミド等の絶縁性材料からなる平坦化絶縁膜（図示せず）が設けられていてもよい。 TFT 12 is a switching element for selecting a pixel. The TFT 12 may be, for example, an inorganic TFT using an inorganic semiconductor layer such as amorphous silicon, polysilicon, or oxide as a channel layer (active layer), or an organic TFT using an organic semiconductor layer such as pentacene. The TFT 12 is covered with, for example, a protective layer 13. A flattening insulating film (not shown) made of an insulating material such as polyimide may be further provided on the protective layer 13.
　画素電極１４は、画素毎に独立して形成されており、例えば、金（Ａｕ）、銀（Ａｇ）または銅（Ｃｕ）等の導電性材料のいずれか１種類または２種類以上を含んで形成されている。画素電極１４は、ＴＦＴ１２に電気的に接続されている。なお、１つの画素電極１４に対して配置されるＴＦＴ１２の数は任意であり、１つに限らず、２つ以上でもよい。 The pixel electrode 14 is formed independently for each pixel, and includes, for example, one or more of conductive materials such as gold (Au), silver (Ag), and copper (Cu). Has been. The pixel electrode 14 is electrically connected to the TFT 12. Note that the number of TFTs 12 arranged for one pixel electrode 14 is arbitrary, and is not limited to one, and may be two or more.
　接着層１５は、駆動基板１０と後述する表示層と貼り合わせるものであり、例えばアクリル系樹脂、ウレタン系樹脂またはゴムにより構成され、厚みが例えば１μｍ～１００μｍである。なお、接着層１５には、導電性を持たせることを目的として、例えばアニオン系添加剤、カチオン系添加剤またはリチウム塩系添加剤等が添加されていてもよい。 The adhesive layer 15 is bonded to the drive substrate 10 and a display layer described later, and is made of, for example, an acrylic resin, a urethane resin, or rubber, and has a thickness of, for example, 1 μm to 100 μm. For example, an anionic additive, a cationic additive, or a lithium salt additive may be added to the adhesive layer 15 for the purpose of providing conductivity.
　対向基板２０は、支持部材２１の一面側（表示層側）に対向電極２２が設けられたものである。この他、例えば、カラーフィルタや接着層等（いずれも図示せず）が積層されていてもよい。 The counter substrate 20 is provided with a counter electrode 22 on one surface side (display layer side) of the support member 21. In addition, for example, a color filter, an adhesive layer, and the like (none of which are shown) may be laminated.
　支持部材２１は、光透過性であることを除き、支持部材１１と同様の材料により構成されている。対向基板２０の上面側に画像が表示されるため、支持部材２１は光透過性である必要があるからである。この支持部材２１の厚みは、例えば１μｍ～２５０μｍである。 The support member 21 is made of the same material as the support member 11 except that it is light transmissive. This is because the image is displayed on the upper surface side of the counter substrate 20, and thus the support member 21 needs to be light transmissive. The thickness of the support member 21 is, for example, 1 μm to 250 μm.
　対向電極２２は、例えば、光透過性を有する導電性材料（透明導電材料）のいずれか１種類または２種類以上を含んで形成されている。このような導電性材料としては、例えば、酸化インジウム－酸化スズ（ＩＴＯ）、酸化アンチモン－酸化スズ（ＡＴＯ）、フッ素ドープ酸化スズ（ＦＴＯ）またはアルミニウムドープ酸化亜鉛（ＡＺＯ）等が挙げられる。この対向電極２２の厚みは、例えば０．００１μｍ～１μｍである。なお、対向電極２２は、例えば、支持部材２１の一面に全面形成されているが、画素電極１４と同様に、例えば画素毎に分割形成されていてもよい。 The counter electrode 22 is formed including, for example, any one type or two or more types of conductive materials (transparent conductive materials) having optical transparency. Examples of such a conductive material include indium oxide-tin oxide (ITO), antimony oxide-tin oxide (ATO), fluorine-doped tin oxide (FTO), and aluminum-doped zinc oxide (AZO). The thickness of the counter electrode 22 is, for example, 0.001 μm to 1 μm. The counter electrode 22 is formed on the entire surface of the support member 21, for example. However, like the pixel electrode 14, the counter electrode 22 may be formed separately for each pixel, for example.
　対向基板２０側に画像を表示する場合には、対向電極２２を介して電気泳動素子３０を見ることになるため、対向電極２２の光透過率はできるだけ高いことが好ましく、例えば、８０％以上である。また、対向電極２２の電気抵抗は、できるだけ低いことが好ましく、例えば、１００Ω／□（スクエア）以下である。 When displaying an image on the counter substrate 20 side, since the electrophoretic element 30 is viewed through the counter electrode 22, the light transmittance of the counter electrode 22 is preferably as high as possible, for example, 80% or more. is there. The electric resistance of the counter electrode 22 is preferably as low as possible, for example, 100Ω / □ (square) or less.
　表示層には、例えば、画素毎に電圧制御される電気泳動素子３０が設けられている。電気泳動素子３０は、電気泳動現象を利用してコントラストを生じさせるものであり、電界に応じて画素電極１４と対向電極２２との間を移動可能な泳動粒子３２を含んでいる。電気泳動素子３０は、例えば、上記のように、絶縁性液体３１中に泳動粒子３２と共に、多孔質層３３を含んでおり、ここでは、絶縁性液体３１および多孔質層３３は各画素に共通して設けられている。 In the display layer, for example, an electrophoretic element 30 that is voltage-controlled for each pixel is provided. The electrophoretic element 30 generates contrast using an electrophoretic phenomenon, and includes electrophoretic particles 32 that can move between the pixel electrode 14 and the counter electrode 22 in accordance with an electric field. For example, as described above, the electrophoretic element 30 includes the porous layer 33 together with the electrophoretic particles 32 in the insulating liquid 31. Here, the insulating liquid 31 and the porous layer 33 are common to each pixel. Is provided.
　表示装置１は、例えば、以下のように製造される。まず、支持部材２１の一面に対向電極２２を、各種成膜法等の既存の方法を用いて設け、対向基板２０を形成する。次に、対向電極２２上にスペーサ３５を形成する。スペーサ３５は、例えば、以下のようなインプリント法により形成することができる。まず、スペーサ３５の構成材料（例えば、感光性樹脂材料）を含む溶液を対向電極２２上に塗布する。次いで、塗布面に凹部を有する型を押し当て、感光させた後、型を外す。これにより、柱状のスペーサ３５が形成される。 The display device 1 is manufactured as follows, for example. First, the counter electrode 22 is provided on one surface of the support member 21 using an existing method such as various film forming methods, and the counter substrate 20 is formed. Next, a spacer 35 is formed on the counter electrode 22. The spacer 35 can be formed by, for example, the following imprint method. First, a solution containing a constituent material (for example, a photosensitive resin material) of the spacer 35 is applied onto the counter electrode 22. Next, a mold having a recess on the coated surface is pressed and exposed to light, and then the mold is removed. Thereby, the columnar spacer 35 is formed.
　続いて、隣り合うスペーサ３５の間、即ち、セル３４内に多孔質層３３を配設する。多孔質層３３は、以下の工程を経て形成される。まず、有機溶剤等に繊維状構造体３３１の形成材料（例えば、高分子材料等）を分散または溶解させて紡糸溶液を調製する。続いて、紡糸溶液に非泳動粒子３３２を加えたのち、十分に攪拌して非泳動粒子３３２を紡糸溶液中に分散させる。次に、この紡糸溶液を用いて、例えば、静電紡糸法により紡糸を行う。これにより、繊維状構造体３３１により非泳動粒子３３２が保持された多孔質層３３が形成される。なお、多孔質層３３の孔径は、紡糸溶液の粘度や、非泳動粒子３３２の粒径および静電紡糸時におけるスキャン速度を制御することによって制御される。例えば、多孔質層３３Ａでは、厚み圧縮量を０％～１０％、多孔質層３３Ｂでは１０％～２０％、多孔質層３３Ｃでは、２０％～３０％、多孔質層３３Ｄでは３０％～４０％の条件を用いて多孔質膜を圧縮することにより、上記平均孔径の範囲を有する多孔質層３３Ａ，３３Ｂ，３３Ｃ，３３Ｄが形成される。なお、繊維状構造体３３１は、静電紡糸法に代えて、相分離法、相反転法、溶融紡糸法、湿式紡糸法、乾式紡糸法、ゲル紡糸法、ゾルゲル法およびスプレー塗布法等によって形成してもよい。 Subsequently, the porous layer 33 is disposed between the adjacent spacers 35, that is, in the cells 34. The porous layer 33 is formed through the following steps. First, a spinning solution is prepared by dispersing or dissolving a material for forming the fibrous structure 331 (for example, a polymer material) in an organic solvent or the like. Subsequently, after adding the non-migrating particles 332 to the spinning solution, the non-migrating particles 332 are dispersed in the spinning solution by sufficiently stirring. Next, using this spinning solution, for example, spinning is performed by an electrostatic spinning method. Thereby, the porous layer 33 in which the non-migrating particles 332 are held by the fibrous structure 331 is formed. The pore diameter of the porous layer 33 is controlled by controlling the viscosity of the spinning solution, the particle diameter of the non-electrophoretic particles 332, and the scanning speed during electrostatic spinning. For example, the thickness compression amount of the porous layer 33A is 0% to 10%, the porous layer 33B is 10% to 20%, the porous layer 33C is 20% to 30%, and the porous layer 33D is 30% to 40%. The porous layer 33A, 33B, 33C, 33D having the above average pore diameter range is formed by compressing the porous membrane using the% condition. The fibrous structure 331 is formed by a phase separation method, a phase inversion method, a melt spinning method, a wet spinning method, a dry spinning method, a gel spinning method, a sol-gel method, a spray coating method, or the like instead of the electrostatic spinning method. May be.
　続いて、多孔質層３３が配置された対向基板２０に、泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄを分散させた絶縁性液体３１を塗布したのち、これを、例えば、封止剤（図示せず）を介してシール層１６が配設された剥離部材（図示せず）を対向させる。最後に、剥離部材を剥がしたのち、シール層１６上に接着層１５を介してＴＦＴ１２および画素電極１４等が形成された駆動基板１０を固定する。以上の工程により、表示装置１が完成する。 Subsequently, after applying the insulating liquid 31 in which the migrating particles 32A, 32B, 32C, and 32D are dispersed to the counter substrate 20 on which the porous layer 33 is disposed, this is treated with, for example, a sealing agent (not shown). ), A peeling member (not shown) provided with the seal layer 16 is opposed. Finally, after peeling off the peeling member, the driving substrate 10 on which the TFT 12 and the pixel electrode 14 and the like are formed on the seal layer 16 via the adhesive layer 15 is fixed. The display device 1 is completed through the above steps.
（１－３．表示装置の好ましい表示方法）
　電気泳動素子３０を備えた表示装置１では、上記のように、泳動粒子３２の光反射率と、多孔質層３３の光反射率との違いを利用してコントラストを生じる。 (1-3. Preferred Display Method of Display Device)
In the display device 1 including the electrophoretic element 30, as described above, contrast is generated by utilizing the difference between the light reflectance of the electrophoretic particles 32 and the light reflectance of the porous layer 33.
　図３Ａおよび図３Ｂは、電気泳動素子３０の基本的な表示動作を説明するための模式図である。なお、ここではわかりやすくするために、多孔質層３３を単層として示すと共に、多孔質層３３と駆動基板１０および対向基板２０との間に、泳動粒子３２が配置される領域（待機領域Ｒ１および表示領域Ｒ２）を示した。また、最も粒径の小さな泳動粒子３２Ｄを例に説明する。 3A and 3B are schematic diagrams for explaining a basic display operation of the electrophoretic element 30. FIG. Here, for the sake of clarity, the porous layer 33 is shown as a single layer, and the region in which the migrating particles 32 are disposed between the porous layer 33 and the drive substrate 10 and the counter substrate 20 (standby region R1). And the display region R2). Further, the migrating particle 32D having the smallest particle size will be described as an example.
　初期状態の電気泳動素子３０では、例えば、泳動粒子３２Ｄは待機領域Ｒ１に配置されている（図３Ａ）。この場合には、全ての画素で泳動粒子３２Ｄが多孔質層３３により隠蔽されているため、対向基板２０側から電気泳動素子３０を見ると、コントラストが生じていない（画像が表示されていない）状態にある。 In the electrophoretic element 30 in the initial state, for example, the migrating particles 32D are arranged in the standby region R1 (FIG. 3A). In this case, since the migrating particles 32D are concealed by the porous layer 33 in all the pixels, no contrast is generated when the electrophoretic element 30 is viewed from the counter substrate 20 side (an image is not displayed). Is in a state.
　一方、ＴＦＴ１２により画素が選択され、画素電極１４と対向電極２２との間に電界が印加されると、図３Ｂに示したように、画素毎に泳動粒子３２Ｄが待機領域Ｒ１から多孔質層３３の細孔３３３を経由して表示領域Ｒ２に移動する。この場合には、泳動粒子３２が多孔質層３３により隠蔽されている画素と隠蔽されていない画素とが併存するため、対向基板２０側から電気泳動素子３０を見ると、コントラストが生じている状態になる。これにより、画像が表示される。 On the other hand, when a pixel is selected by the TFT 12 and an electric field is applied between the pixel electrode 14 and the counter electrode 22, as shown in FIG. 3B, the migrating particles 32D are transferred from the standby region R1 to the porous layer 33 for each pixel. It moves to the display region R2 via the pore 333. In this case, since the migrating particles 32 are both concealed by the porous layer 33 and non-hidden, the contrast is generated when the electrophoretic element 30 is viewed from the counter substrate 20 side. become. Thereby, an image is displayed.
　なお、駆動基板１０には、上記電気泳動素子３０を画素毎に駆動する（画素電極１４および対向電極２２間に駆動電圧を印加する）ための周辺回路（図示せず）が設けられている。周辺回路は、例えば、アクティブマトリクス方式の駆動回路を形成するための電圧制御用のドライバ、電源およびメモリ等を含んでおり、１または２以上の選択的なサブピクセルに対して画像信号に対応する駆動電圧を印加可能となっている。 The drive substrate 10 is provided with a peripheral circuit (not shown) for driving the electrophoretic element 30 for each pixel (applying a drive voltage between the pixel electrode 14 and the counter electrode 22). The peripheral circuit includes, for example, a voltage control driver for forming an active matrix driving circuit, a power source, a memory, and the like, and corresponds to an image signal for one or more selective sub-pixels. A drive voltage can be applied.
　本実施の形態の電気泳動素子３０は、上記のように、絶縁性液体３１中に、複数種類の平均粒径を有する共に、その平均粒径ごとに色分けされた泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄと、それぞれ平均孔径が異なる細孔３３３を有する多孔質層３３Ａ，３３Ｂ，３３Ｃ，３３Ｄとを含んでいる。 As described above, the electrophoretic element 30 according to the present embodiment has a plurality of types of average particle diameters in the insulating liquid 31, and the electrophoretic particles 32A, 32B, 32C, which are color-coded according to the average particle diameter. 32D and porous layers 33A, 33B, 33C, and 33D having pores 333 having different average pore diameters.
　図４は、表示装置１の動作を説明する模式図である。図１および図４に示したように、多孔質層３３は、表示面Ｓ１側から平均孔径の大きな順、ここでは、表示面Ｓ１側から多孔質層３３Ａ，多孔質層３３Ｂ，多孔質層３３Ｃおよび多孔質層３３Ｄの順に積層されている。これら多孔質層３３Ａ，３３Ｂ，３３Ｃ，３３Ｄの平均孔径は、泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄによって決定される。即ち、多孔質層３３Ａの孔径は、全ての泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄが通過できる大きさに、多孔質層３３Ｂの孔径は、泳動粒子３２Ａは通過できないが、泳動粒子３２Ｂ，３２Ｃ，３２Ｄは通過可能な大きさに、多孔質層３３Ｃは、泳動粒子３２Ａ，３２Ｂは通過できないが、泳動粒子３２Ｃ，３２Ｄは通過できる大きさに、多孔質層３３Ｄは、泳動粒子３２Ａ，３２Ｂ，３２Ｃは通過できないが、泳動粒子３２Ｄは通過できる大きさに、それぞれ形成されている。これにより、画素電極１４と対向電極２２との間に電界を印加した際に、泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄを、それぞれ異なる位置に留まらせることが可能となる。 FIG. 4 is a schematic diagram for explaining the operation of the display device 1. As shown in FIGS. 1 and 4, the porous layer 33 has a larger average pore diameter from the display surface S1 side, here, the porous layer 33A, the porous layer 33B, and the porous layer 33C from the display surface S1 side. And the porous layer 33D in this order. The average pore diameter of the porous layers 33A, 33B, 33C, and 33D is determined by the migrating particles 32A, 32B, 32C, and 32D. That is, the pore size of the porous layer 33A is such that all the migrating particles 32A, 32B, 32C, and 32D can pass, and the pore size of the porous layer 33B cannot pass the migrating particle 32A, but the migrating particles 32B, 32C, The porous layer 33C cannot pass through the migrating particles 32A and 32B, but the porous layer 33C can pass through the migrating particles 32A, 32B, and 32C. Can not pass through, but the migrating particles 32D are formed in sizes that can pass through. Thus, when an electric field is applied between the pixel electrode 14 and the counter electrode 22, the migrating particles 32A, 32B, 32C, and 32D can be kept at different positions.
　図５Ａ～７Ｂは、表示装置１の表示動作を説明するための泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄの移動を表す概念図（図５Ａ，図６Ａ，図７Ａ）および印加電圧の波形（図５Ｂ，図６Ｂ，図７Ｂ）を表したものである。泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄは、それぞれ、シアン色（泳動粒子３２Ａ），マゼンタ色（泳動粒子３２Ｂ），黄色（泳動粒子３２Ｃ）および黒色（泳動粒子３２Ｄ）に着色されているものとする。以下に、シアン表示、マゼンタ表示、黄表示する際の泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄの移動および印加電圧の波形についてこの順に説明する。 5A to 7B are conceptual diagrams (FIGS. 5A, 6A, and 7A) showing movement of the migrating particles 32A, 32B, 32C, and 32D for explaining the display operation of the display device 1, and waveforms of applied voltages (FIG. 5B). 6B and FIG. 7B). The electrophoretic particles 32A, 32B, 32C, and 32D are colored cyan (electrophoretic particles 32A), magenta (electrophoretic particles 32B), yellow (electrophoretic particles 32C), and black (electrophoretic particles 32D), respectively. . In the following, the movement of the migrating particles 32A, 32B, 32C, and 32D and the waveform of the applied voltage when performing cyan display, magenta display, and yellow display will be described in this order.
　まず、シアン表示について説明する。本実施の形態の電気泳動素子３０では、上述したように、初期状態（画素電極１４と対向電極２２との間に電圧無印加の状態）では、泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄは、待機領域Ｒ１に局在する。具体的には、泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄが、それぞれ通過可能な多孔質層３３Ａ，３３Ｂ，３３Ｃ，３３Ｄの背面Ｓ２側に配置されている（図５Ａの時間０）。このとき、表示色は、多孔質層３３の色、即ち、白色となる。ここで、画素電極１４と対向電極２２との間に、例えば、正の電圧を印加すると、泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄは、それぞれ表示面Ｓ１側に移動する。このとき、図５Ｂに示したように、正の電圧を一定時間（具体的には、泳動粒子３２Ａが表示面Ｓ１に到達するまで）印加したのち停止すると、図５Ａに示したように、泳動粒子３２Ａは多孔質層３３の最表面に、泳動粒子３２Ｂ、３２Ｃ，３２Ｄは、多孔質層３３中に配置された状態となる。即ち、この電気泳動素子３０を備えた画素の表示色は、シアン色となる。 First, the cyan display will be described. In the electrophoretic element 30 of the present embodiment, as described above, in the initial state (a state in which no voltage is applied between the pixel electrode 14 and the counter electrode 22), the electrophoretic particles 32A, 32B, 32C, and 32D are on standby. It is localized in the region R1. Specifically, the migrating particles 32A, 32B, 32C, and 32D are respectively disposed on the back surface S2 side of the porous layers 33A, 33B, 33C, and 33D that can pass (time 0 in FIG. 5A). At this time, the display color is the color of the porous layer 33, that is, white. Here, for example, when a positive voltage is applied between the pixel electrode 14 and the counter electrode 22, the migrating particles 32A, 32B, 32C, and 32D move to the display surface S1 side. At this time, as shown in FIG. 5B, when a positive voltage is applied for a certain time (specifically, until the migrating particles 32A reach the display surface S1) and then stopped, as shown in FIG. The particles 32A are arranged on the outermost surface of the porous layer 33, and the migrating particles 32B, 32C, and 32D are arranged in the porous layer 33. That is, the display color of the pixel including the electrophoretic element 30 is cyan.
　次に、マゼンタ表示について説明する。例えば、正の電圧をシアン表示時よりも長く印加したのち負の電圧を一定時間印加し停止すると、表示面Ｓ１側には、マゼンタ色に着色された泳動粒子３２Ｂが配置され、泳動粒子３２Ａ，３２Ｃ，３２Ｄは多孔質層３３中に配置された状態となる。詳細には、図６Ｂに示したように、シアン表示時よりも正の電圧を長時間印加することによって、図６Ａに示したように、初期状態において泳動粒子３２Ａよりも背面Ｓ２側に位置する泳動粒子３２Ｂが表示面Ｓ１に移動する。この後、負の電圧を印加することによって、泳動粒子３２Ｂよりも移動速度の大きな泳動粒子３２Ａが泳動粒子３２Ｂよりも先に背面Ｓ２側に移動する。ここで、電圧の印加を停止することによって、泳動粒子３２Ｂは多孔質層３３の最表面に、泳動粒子３２Ａおよび他の泳動粒子３２Ｃ，３２Ｄは多孔質層３３中に配置される。即ち、この電気泳動素子３０を備えた画素の表示色は、マゼンタ色となる。 Next, the magenta display will be described. For example, when a positive voltage is applied for a longer time than when cyan is displayed and then a negative voltage is applied for a predetermined time and then stopped, the migrating particles 32B colored in magenta are arranged on the display surface S1 side. 32C and 32D are arranged in the porous layer 33. Specifically, as shown in FIG. 6B, by applying a positive voltage for a longer time than in the cyan display mode, as shown in FIG. 6A, the electrophoretic particles 32A are positioned on the back surface S2 side in the initial state. The migrating particles 32B move to the display surface S1. Thereafter, by applying a negative voltage, the migrating particles 32A having a larger moving speed than the migrating particles 32B move to the back surface S2 side before the migrating particles 32B. Here, by stopping the application of voltage, the migrating particles 32B are arranged on the outermost surface of the porous layer 33, and the migrating particles 32A and the other migrating particles 32C and 32D are arranged in the porous layer 33. That is, the display color of the pixel provided with the electrophoretic element 30 is magenta.
　次に、黄表示について説明する。例えば、正の電圧をマゼンタ表示時よりも長く印加したのち負の電圧をマゼンタ表示時よりも長時間印加し停止すると、表示面Ｓ１側には、黄色に着色された泳動粒子３２Ｃが配置され、泳動粒子３２Ａ，３２Ｂ，３２Ｄは多孔質層３３中に配置された状態となる。詳細には、図７Ａに示したように、マゼンタ表示時よりも正の電圧を長時間印加することによって、図７Ｂに示したように、初期状態において泳動粒子３２Ａ，３２Ｂよりも背面Ｓ２側に位置した泳動粒子３２Ｃが表示面Ｓ１に移動する。この後、負の電圧を印加すると、泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄは背面Ｓ２側に移動を始める。このとき、泳動粒子３２Ａ，３２Ｂは、泳動粒子３２Ｃよりも移動速度の大きいため、泳動粒子３２Ｃよりも先に背面Ｓ２側に移動する。ここで、電圧の印加を停止することによって、泳動粒子３２Ｃは多孔質層３３の最表面に、泳動粒子３２Ａ，３２Ｂ，３２Ｄは多孔質層３３中に配置される。即ち、この電気泳動素子３０を備えた画素の表示色は、黄色となる。 Next, the yellow display will be described. For example, when a positive voltage is applied for a longer time than when magenta is displayed and then a negative voltage is applied for a longer time than when magenta is displayed and then stopped, electrophoretic particles 32C colored yellow are disposed on the display surface S1 side. The migrating particles 32 </ b> A, 32 </ b> B, and 32 </ b> D are arranged in the porous layer 33. More specifically, as shown in FIG. 7A, by applying a positive voltage for a longer time than when displaying magenta, as shown in FIG. 7B, in the initial state, the back side S2 side of the migrating particles 32A and 32B. The positioned migrating particles 32C move to the display surface S1. Thereafter, when a negative voltage is applied, the migrating particles 32A, 32B, 32C, and 32D start to move toward the back surface S2. At this time, since the migrating particles 32A and 32B have a higher moving speed than the migrating particles 32C, they move to the back surface S2 side before the migrating particles 32C. Here, by stopping the application of voltage, the migrating particles 32C are arranged on the outermost surface of the porous layer 33, and the migrating particles 32A, 32B, and 32D are arranged in the porous layer 33. That is, the display color of the pixel including the electrophoretic element 30 is yellow.
　なお、図示していないが、電気泳動素子３０を備えた画素の表示色を黒色とする場合には、例えば、正の電圧を黄色表示時よりも長く印加したのち負の電圧を黄色表示時よりも長時間印加したのち停止することによって、多孔質層３３の最表面に黒色に着色された泳動粒子３２Ｄが、多孔質層３３中に泳動粒子３２Ａ，３２Ｂ，３２Ｃが配置された状態となる。これにより、この電気泳動素子３０を備えた画素の表示色は、黒色となる。 Although not shown, when the display color of the pixel including the electrophoretic element 30 is black, for example, a positive voltage is applied for a longer time than yellow display, and then a negative voltage is applied from yellow display. In addition, by stopping after being applied for a long time, the migrating particles 32D colored black on the outermost surface of the porous layer 33 are in a state in which the migrating particles 32A, 32B, and 32C are arranged in the porous layer 33. As a result, the display color of the pixel including the electrophoretic element 30 is black.
　以上のように、本実施の形態の電気泳動素子３０は、印加電圧の向き（正／負）および印加時間を制御することで、多色、ここでは、シアン色，マゼンタ色，黄色，黒色および白色の５色表示が可能となる。 As described above, the electrophoretic element 30 according to the present embodiment controls the direction (positive / negative) and application time of the applied voltage, so that it is multicolored, in this case, cyan, magenta, yellow, black, and White five-color display is possible.
（１－４．作用・効果）
　前述したように、電気泳動型の表示装置において多色表示を行う方法として、色および粒径の異なる複数の泳動粒子を用いた表示装置が開示されている（例えば、特許文献１）。しかしながら、この表示装置では、各色の泳動粒子の移動速度の差のみで表示色を制御するため、表示色の切り替えに一定の時間を要する。 (1-4. Action and effect)
As described above, as a method for performing multicolor display in an electrophoretic display device, a display device using a plurality of electrophoretic particles having different colors and particle sizes is disclosed (for example, Patent Document 1). However, in this display device, since the display color is controlled only by the difference in the moving speed of the migrating particles of each color, it takes a certain time to switch the display color.
　図８Ａおよび図８Ｂは、比較例としての電気泳動素子における泳動粒子の移動を表す概念図（図８Ａ）および印加電圧の波形図（図８Ｂ）である。この電気泳動素子は、特許文献１に記載の表示装置が備えた電気泳動素子のように、各色の泳動粒子の移動速度の差のみで表示色を制御するものである。ここでは、この電気泳動素子は、本実施の形態と同様に４種類の泳動粒子１３２Ａ，１３２Ｂ，１３２Ｃ，１３２Ｄを有するものとする。また、各泳動粒子１３２Ａ，１３２Ｂ，１３２Ｃ，１３２Ｄの粒径の大きさおよび呈する色は、それぞれ、本実施の形態の泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄに準ずるものとする。 FIG. 8A and FIG. 8B are a conceptual diagram (FIG. 8A) showing the movement of electrophoretic particles in an electrophoretic element as a comparative example, and a waveform diagram of an applied voltage (FIG. 8B). This electrophoretic element controls the display color only by the difference in the moving speed of the electrophoretic particles of each color, like the electrophoretic element provided in the display device described in Patent Document 1. Here, it is assumed that the electrophoretic element has four types of electrophoretic particles 132A, 132B, 132C, and 132D as in the present embodiment. In addition, the size and the color of each migrating particle 132A, 132B, 132C, 132D are the same as those of the migrating particle 32A, 32B, 32C, 32D of the present embodiment, respectively.
　この電気泳動素子を備えた画素を、例えば、黄表示にさせるためには、図８Ａおよび図８Ｂに示したように、例えば、正の電圧を印加して、少なくとも、背面Ｓ２００に配置された黄色の泳動粒子１３２Ｃを表示面Ｓ１００に移動させる必要がある。この電気泳動素子は、初期状態では、泳動粒子１３２Ａ，１３２Ｂ，１３２Ｃ，１３２Ｄは、全て背面Ｓ２００に局在する。このため、黄色の泳動粒子１３２Ｃを表示面Ｓ１００に移動させるためには、本実施の形態の電気泳動素子３０よりも長い時間を要する（図８Ａ，図８Ｂ参照）。また、その後、負の電圧を印加して表示面Ｓ１００に移動した泳動粒子１３２Ａ，１３２Ｂ，１３２Ｃのうち、泳動粒子１３２Ｃのみを表示面Ｓ１００に配置するためにも、電気泳動素子３０よりも長い時間を要する。 For example, in order to display the pixel including the electrophoretic element in yellow, as shown in FIGS. 8A and 8B, for example, a positive voltage is applied, and at least the yellow color arranged on the back surface S200 is displayed. It is necessary to move the electrophoretic particles 132C to the display surface S100. In the electrophoretic element, the electrophoretic particles 132A, 132B, 132C, and 132D are all localized on the back surface S200 in the initial state. For this reason, in order to move the yellow electrophoretic particles 132C to the display surface S100, it takes a longer time than the electrophoretic element 30 of the present embodiment (see FIGS. 8A and 8B). Further, in order to place only the electrophoretic particles 132C on the display surface S100 among the electrophoretic particles 132A, 132B, and 132C that have moved to the display surface S100 by applying a negative voltage thereafter, the time is longer than that of the electrophoretic element 30. Cost.
　このように、泳動粒子の移動速度の差のみで多色表示を行おうとすると、短時間で表示色の切り替えを行うことは難しかった。また、表示面において、複数色の泳動粒子の濃度を制御する方法が確立されていなかったため、実際に、このような構成の電気泳動素子を用いて、表示面に複数の色を同時に表示可能な表示装置を実現することは困難であった。 As described above, when the multicolor display is performed only by the difference in the moving speed of the migrating particles, it is difficult to switch the display color in a short time. In addition, since a method for controlling the concentration of electrophoretic particles of a plurality of colors has not been established on the display surface, it is actually possible to simultaneously display a plurality of colors on the display surface using the electrophoretic element having such a configuration. It has been difficult to realize a display device.
　この他、多色表示が可能な反射型の表示装置としては、カラーフィルタを設けた表示装置が挙げられる。しかしながら、カラーフィルタを設けた場合には、カラーフィルタを設けることによる反射率の低下およびカラーフィルタによる反射光の吸収等により、コントラストおよび輝度が大幅に低下してしまうという虞がある。 In addition, examples of a reflective display device capable of multicolor display include a display device provided with a color filter. However, when the color filter is provided, there is a risk that the contrast and the brightness may be significantly reduced due to a decrease in reflectance due to the provision of the color filter and absorption of reflected light by the color filter.
　これに対して、本実施の形態の表示装置１では、泳動粒子３２として、互いに平均粒径が異なると共に、平均粒径ごとに異なる色に着色された４種類の泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄを用いるようにした。また、多孔質層３３を、細孔３３３の平均孔径が互いに異なる４種類の多孔質層３３Ａ，３３Ｂ，３３Ｃ，３３Ｄから構成し、これらを表示面Ｓ１側から背面Ｓ２側にかけて平均孔径が小さくなる順に積層した。これにより、各色の泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄの移動距離がその粒径および多孔質層３３Ａ，３３Ｂ，３３Ｃ，３３Ｄの孔径によって制限される。即ち、泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄは、例えば、初期状態において、それぞれ通過可能な多孔質層３３Ａ，３３Ｂ，３３Ｃ，３３Ｄの背面Ｓ２側に局在するようになり、電圧印加時における泳動粒子３２Ａ，３２Ｂ，３２Ｃ，３２Ｄの移動距離が、最も粒径の小さな泳動粒子３２Ｄ以外の泳動粒子３２Ａ，３２Ｂ，３２Ｃでは短くなる。 On the other hand, in the display device 1 of the present embodiment, as the migrating particles 32, four types of migrating particles 32A, 32B, 32C, which have different average particle sizes and are colored in different colors for each average particle size. 32D was used. The porous layer 33 is composed of four types of porous layers 33A, 33B, 33C, and 33D having different average pore diameters of the pores 333, and these average pore diameters decrease from the display surface S1 side to the back surface S2 side. Laminated in order. Thereby, the moving distance of each color migrating particle 32A, 32B, 32C, 32D is limited by the particle diameter and the pore diameter of the porous layers 33A, 33B, 33C, 33D. That is, the migrating particles 32A, 32B, 32C, and 32D are localized on the back surface S2 side of the porous layers 33A, 33B, 33C, and 33D that can pass, respectively, in the initial state, for example. The moving distance of the particles 32A, 32B, 32C, 32D is shorter in the migrating particles 32A, 32B, 32C other than the migrating particle 32D having the smallest particle size.
　以上のように、本実施の形態の表示装置１では、互いに平均粒径が異なると共に、平均粒径ごとに異なる色に着色された複数種類の泳動粒子３２と、表示面Ｓ１側から背面Ｓ２側にかけて平均孔径が小さくなる順に積層される複数種類の多孔質層３３とを含む電気泳動素子３０を表示素子として用いるようにした。これにより、例えば、初期状態における泳動粒子３２（３２Ａ，３２Ｂ，３２Ｃ，３２Ｄ）の位置が、積層された多孔質層３３（３３Ａ，３３Ｂ，３３Ｃ，３３Ｄ）の孔径によって制御される。即ち、粒径の最も大きな泳動粒子３２Ａは最も表示面Ｓ１に近い位置に、粒径の最も小さな泳動粒子３２Ｄが最も表示面Ｓ１に遠い位置に配置されるようになる。よって、ある色表示を行う際に、電圧を印加することによって所望の色を呈する泳動粒子を表示面Ｓ１に配置すると共に、他の色の泳動粒子を多孔質層中に移動させて隠蔽するための選別時間を短縮することが可能となる。即ち、表示切り替えに要する時間を短縮することが可能となる。よって、表示品位を向上させつつ、多色表示が可能な表示装置１を提供することが可能となる。 As described above, in the display device 1 according to the present embodiment, the plurality of types of migrating particles 32 having different average particle diameters and different colors for each average particle diameter, and the display surface S1 side to the back surface S2 side. Thus, the electrophoretic element 30 including a plurality of types of porous layers 33 stacked in order of decreasing average pore diameter is used as a display element. Thereby, for example, the position of the migrating particle 32 (32A, 32B, 32C, 32D) in the initial state is controlled by the pore diameter of the laminated porous layer 33 (33A, 33B, 33C, 33D). That is, the migrating particle 32A having the largest particle size is arranged at the position closest to the display surface S1, and the migrating particle 32D having the smallest particle size is arranged at the position farthest from the display surface S1. Therefore, when performing a certain color display, the electrophoretic particles exhibiting a desired color are arranged on the display surface S1 by applying a voltage, and the electrophoretic particles of other colors are moved and concealed in the porous layer. It is possible to shorten the sorting time. That is, it is possible to shorten the time required for display switching. Therefore, it is possible to provide the display device 1 capable of multicolor display while improving display quality.
　以下、上記実施の形態の変形例（変形例１，２）について説明する。以降の説明において上記実施の形態と同一構成部分については同一符号を付してその説明は適宜省略する。 Hereinafter, modified examples (modified examples 1 and 2) of the above embodiment will be described. In the following description, the same components as those in the above embodiment are denoted by the same reference numerals, and the description thereof is omitted as appropriate.
＜２．変形例１＞
　図９は、上記実施の形態の変形例１に係る表示装置（表示装置２）の断面構成を表したものである。この表示装置２は、電気泳動現象を利用してコントラストを生じさせ、画像を表示する表示装置、例えば電子ペーパーディスプレイ等の多様な電子機器に適用されるものである。表示装置２は、例えば、スペーサ３５を介して対向配置された駆動基板１０と対向基板２０との間に、電気泳動素子３０を含む表示層を備えたものである。電気泳動素子４０は、絶縁性液体４１中に、泳動粒子４２と複数の細孔を有する多孔質層４３とを含んで構成されている。多孔質層４３は、繊維状構造体およびこの繊維状構造体に保持された非泳動粒子を有する（いずれも図示せず）。なお、図９は電気泳動素子４０の構成を模式的に表したものであり、実際の寸法、形状とは異なる場合がある。 <2. Modification 1>
FIG. 9 illustrates a cross-sectional configuration of a display device (display device 2) according to Modification 1 of the above embodiment. The display device 2 is applied to various electronic devices such as an electronic paper display, for example, an electronic paper display that generates contrast by using an electrophoretic phenomenon and displays an image. The display device 2 includes, for example, a display layer including the electrophoretic element 30 between the drive substrate 10 and the counter substrate 20 that are disposed to face each other with the spacer 35 interposed therebetween. The electrophoretic element 40 includes an insulating liquid 41 including electrophoretic particles 42 and a porous layer 43 having a plurality of pores. The porous layer 43 has a fibrous structure and non-migrating particles held by the fibrous structure (none of which are shown). FIG. 9 schematically shows the configuration of the electrophoretic element 40 and may differ from the actual size and shape.
（２－１．電気泳動素子の構成）
　本変形例の電気泳動素子４０は、泳動粒子４２として、複数種類の平均粒径、例えば、互いに平均粒径の異なる泳動粒子４２Ａおよび泳動粒子４２Ｂを有する。また、多孔質層４３として、複数種類の平均孔径、例えば、互いに平均孔径の異なる多孔質層４３Ａおよび多孔質層４３Ｂを有する。本変形例では、この泳動粒子４２Ａ，４２Ｂおよび多孔質層４３Ａ，４３Ｂが、それぞれ帯電すると共に、それぞれその帯電量が異なる点が、上記実施の形態とは異なる。また、表示面Ｓ１側に孔径の小さな多孔質層４３Ａを、背面Ｓ２側に孔径の大きな多孔質層４３Ａを配設した点が上記実施の形態とは異なる。 (2-1. Configuration of electrophoretic element)
The electrophoretic element 40 of the present modification has a plurality of types of average particle diameters, for example, the electrophoretic particles 42A and the electrophoretic particles 42B having different average particle diameters as the electrophoretic particles 42. The porous layer 43 includes a plurality of types of average pore diameters, for example, a porous layer 43A and a porous layer 43B having different average pore diameters. In this modification, the migrating particles 42A and 42B and the porous layers 43A and 43B are charged, and the charge amounts are different from those of the above embodiment. Moreover, the point from which the porous layer 43A with a small hole diameter is arrange | positioned at the display surface S1 side and the porous layer 43A with a large hole diameter at the back surface S2 side is different from the said embodiment.
　絶縁性液体４１は、上記実施の形態と同様に、例えば、有機溶媒等の非水溶媒のいずれか１種類または２種類以上であり、具体的には、パラフィンまたはイソパラフィン等を含んで構成されている。この絶縁性液体４１の粘度および屈折率は、出来るだけ低いことが好ましい。泳動粒子３２の移動性（応答速度）が向上すると共に、それに応じて泳動粒子３２の移動に要するエネルギー（消費電力）が低くなるからである。また、絶縁性液体４１の屈折率と多孔質層３３の屈折率との差が大きくなるため、多孔質層３３の光反射率が高くなるからである。なお、絶縁性液体４１の代わりに、微弱導電性液体を用いてもよい。また、絶縁性液体４１は、必要に応じて各種材料（例えば、着色剤、電荷制御剤、分散安定剤、粘度調整剤、界面活性剤または樹脂等）を含んでいてもよい。 As in the above embodiment, the insulating liquid 41 is, for example, any one type or two or more types of non-aqueous solvents such as organic solvents, and specifically includes paraffin or isoparaffin. Yes. It is preferable that the viscosity and refractive index of the insulating liquid 41 are as low as possible. This is because the mobility (response speed) of the migrating particles 32 is improved, and the energy (power consumption) required to move the migrating particles 32 is lowered accordingly. Moreover, since the difference between the refractive index of the insulating liquid 41 and the refractive index of the porous layer 33 is increased, the light reflectance of the porous layer 33 is increased. Note that a weak conductive liquid may be used instead of the insulating liquid 41. The insulating liquid 41 may contain various materials (for example, a colorant, a charge control agent, a dispersion stabilizer, a viscosity modifier, a surfactant, or a resin) as necessary.
　泳動粒子４２は、電気的に移動可能な１または２以上の荷電粒子であり、絶縁性液体４１中に分散されている。本変形例における泳動粒子４２は、上記のように、互いに平均粒径の異なる泳動粒子４２Ａ，４２Ｂを有し、それぞれ１または２以上の荷電粒子で構成されている。更に、泳動粒子４２Ａ，４２Ｂは、異なる色に着色されている。具体的には、泳動粒子４２Ａ，４２Ｂは、例えば、赤色（泳動粒子４２Ａ）および黒色（泳動粒子４２Ｂ）に着色されている。泳動粒子４２の粒径は、例えば、０．１μｍ以上２μｍ以下の範囲であることが好ましく、泳動粒子４２Ａ，４２Ｂは、この範囲内で、例えば、０．２μｍ（泳動粒子４２Ａ），０．３μｍ（泳動粒子４２Ｂ）となっている。なお、各泳動粒子４２Ａ，４２Ｂの平均粒径は上記範囲に限定されるものではなく、例えば、平均粒径が０．１μｍ以上であれば良い。 The electrophoretic particles 42 are one or more charged particles that are electrically movable, and are dispersed in the insulating liquid 41. As described above, the migrating particles 42 in the present modification include the migrating particles 42A and 42B having different average particle diameters, and are each composed of one or two or more charged particles. Furthermore, the migrating particles 42A and 42B are colored in different colors. Specifically, the electrophoretic particles 42A and 42B are colored, for example, red (electrophoretic particles 42A) and black (electrophoretic particles 42B). The particle size of the migrating particles 42 is preferably in the range of, for example, 0.1 μm or more and 2 μm or less, and the migrating particles 42A and 42B have, for example, 0.2 μm (migrating particles 42A) and 0.3 μm in this range. (Electrophoretic particle 42B). In addition, the average particle diameter of each migrating particle 42A and 42B is not limited to the said range, For example, an average particle diameter should just be 0.1 micrometer or more.
　泳動粒子４２Ａ，４２Ｂは、上記実施の形態における泳動粒子３２と同様に、例えば、有機顔料、無機顔料、染料、炭素材料、金属材料、金属酸化物、ガラスまたは高分子材料（樹脂）等のいずれか１種類または２種類以上の粒子（粉末）である。 The migrating particles 42A and 42B may be any of organic pigments, inorganic pigments, dyes, carbon materials, metal materials, metal oxides, glass, polymer materials (resins), and the like, as with the migrating particles 32 in the above embodiment. Or one kind or two or more kinds of particles (powder).
　絶縁性液体４１中における泳動粒子４２Ａ，４２Ｂの含有量（濃度）は、特に限定されないが、泳動粒子４２全体では、例えば、０．１重量％～１０重量％であることが好ましい。泳動粒子３２による多孔質層３３の遮蔽性、多孔質層３３による泳動粒子３２の隠蔽性および移動性が確保されるからである。０．１重量％よりも少ないと、泳動粒子３２が多孔質層３３を遮蔽しにくくなる可能性がある。一方、１０重量％よりも多いと、泳動粒子３２の分散性が低下するため、泳動粒子３２が泳動しにくくなり、場合によっては凝集する可能性がある。泳動粒子４２Ａ，４２Ｂは、粒径や表面修飾あるいは材質にもよるが、例えば、泳動粒子４２Ａおよび泳動粒子４２Ｂ共に、０．１重量％～４重量％であることが好ましい。 The content (concentration) of the migrating particles 42A and 42B in the insulating liquid 41 is not particularly limited, but the entire migrating particle 42 is preferably, for example, 0.1 wt% to 10 wt%. This is because the shielding property of the porous layer 33 by the migrating particles 32 and the concealing property and mobility of the migrating particles 32 by the porous layer 33 are ensured. If the amount is less than 0.1% by weight, the migrating particles 32 may hardly shield the porous layer 33. On the other hand, when the amount is more than 10% by weight, the dispersibility of the migrating particles 32 is lowered, so that the migrating particles 32 are difficult to migrate and may be aggregated in some cases. For example, both the migrating particles 42A and the migrating particles 42B are preferably 0.1% by weight to 4% by weight although the migrating particles 42A and 42B depend on the particle size, surface modification, or material.
　本変形例における泳動粒子４２Ａ，４２Ｂは、帯電していると共に、互いに異なる帯電量を有する。この帯電量の差は、例えば、表面処理を行うことによって付加することができる。具体的には、例えば、泳動粒子４２Ａ，４２Ｂが、それぞれ負の電荷を有する場合には、例えば、異なる電荷量を有する電子吸引性を有する官能基を修飾することで帯電差を設けることができる。また、泳動粒子４２Ａ，４２Ｂが、それぞれ正の電荷を有する場合には、例えば、それぞれ異なる電荷量を有する電子供与性を有する官能基を修飾することで帯電差を設けることができる。なお、泳動粒子４２Ａ，４２Ｂの表面に修飾させる官能基の量を変えることでも帯電差を設けることができる。 The migrating particles 42A and 42B in this modification are charged and have different charge amounts. This difference in charge amount can be added, for example, by performing a surface treatment. Specifically, for example, when the migrating particles 42A and 42B each have a negative charge, for example, a charge difference can be provided by modifying an electron-withdrawing functional group having a different charge amount. . In addition, when the migrating particles 42A and 42B have positive charges, for example, a charge difference can be provided by modifying functional groups having electron donating properties having different charge amounts. The charge difference can also be provided by changing the amount of the functional group to be modified on the surfaces of the migrating particles 42A and 42B.
　なお、泳動粒子４２Ａおよび泳動粒子４２Ｂの帯電量は、後述する多孔質層４３Ａおよび多孔質層４３Ｂの帯電量との関係から決定される。これは、電圧印加時における泳動粒子４２Ａ，４２Ｂの移動速度に差をつけ、表示切り替えの速度をより向上させるためである。具体的には、泳動粒子４２と多孔質層４３との帯電差が小さい組み合わせの場合には、泳動粒子４２の移動度は大きくなり、帯電差が大きい組み合わせの場合には、泳動粒子４２の移動度は小さくある。また、帯電差が大きすぎると、泳動粒子４２は多孔質層４３を通り抜けることができなくなる。このことから、泳動粒子４２Ｂの帯電量は、例えば、粒径の小さな泳動粒子４２Ａの帯電量よりも大きいことが好ましい。具体的には、泳動粒子４２Ａの帯電量は、例えば、１０ｍＶ以上５０ｍＶ以下であることが好ましく、泳動粒子４２Ｂの帯電量は、例えば、２０ｍＶ以上１００ｍＶ以下であることが好ましい。 Note that the charge amounts of the migrating particles 42A and the migrating particles 42B are determined from the relationship with the charge amounts of the porous layer 43A and the porous layer 43B described later. This is because the moving speed of the migrating particles 42A and 42B at the time of voltage application is differentiated to further improve the display switching speed. Specifically, the mobility of the migrating particles 42 increases in the case of a combination with a small charge difference between the migrating particles 42 and the porous layer 43, and the migration of the migrating particles 42 in a combination with a large charge difference. The degree is small. If the charge difference is too large, the migrating particles 42 cannot pass through the porous layer 43. For this reason, the charge amount of the migrating particles 42B is preferably larger than the charge amount of the migrating particles 42A having a small particle size, for example. Specifically, the charge amount of the migrating particles 42A is preferably 10 mV or more and 50 mV or less, for example, and the charge amount of the migrating particles 42B is preferably 20 mV or more and 100 mV or less, for example.
　多孔質層４３は、上記実施の形態と同様に、繊維状構造体により形成された３次元立体構造物（不織布のような不規則なネットワーク構造物）である。本変形例における多孔質層４３は、互いに孔径の異なる２種類の多孔質層４３Ａおよび多孔質層４３Ｂを有する。また、多孔質層４３Ａ，４３Ｂは、帯電していると共に、それぞれ異なる帯電量を有する。なお、多孔質層４３Ａ，４３Ｂの積層順は、表示面Ｓ１側に細孔の平均孔径の小さな多孔質層４３Ａが、背面Ｓ２側に細孔の平均孔径が大きな多孔質層４３Ｂが配置されている。 The porous layer 43 is a three-dimensional solid structure (irregular network structure such as a nonwoven fabric) formed of a fibrous structure as in the above embodiment. The porous layer 43 in this modification has two types of porous layers 43A and porous layers 43B having different pore sizes. The porous layers 43A and 43B are charged and have different charge amounts. The order of stacking the porous layers 43A and 43B is such that a porous layer 43A having a small average pore diameter is arranged on the display surface S1 side, and a porous layer 43B having a large average pore diameter is arranged on the back surface S2 side. Yes.
　多孔質層４３を構成する材料としては、上記実施の形態において挙げた材料を用いることができる。なお、表示面Ｓ１側に配置される多孔質層４３Ａは光反射性を有していてもよいが、本変形例では、多孔質層４３Ａの孔径は、泳動粒子４２Ｂが通過できないため、光透過性を有することが好ましい。その場合には、多孔質層４３Ａを構成する繊維状構造体には、光学的反射特性を付加する非泳動粒子を含まずに形成されている。背面Ｓ２側に配置される多孔質層４３Ｂは、上記実施の形態における多孔質層３３と同様に、１または２以上の非泳動粒子を含む繊維状構造体によって構成されており、泳動粒子４２Ａ，４２Ｂとは異なる光反射特性を有する。 As the material constituting the porous layer 43, the materials described in the above embodiment can be used. Note that the porous layer 43A disposed on the display surface S1 side may have light reflectivity, but in this modification, the pore size of the porous layer 43A cannot pass through the migrating particles 42B, so that light transmission is possible. It is preferable to have properties. In that case, the fibrous structure constituting the porous layer 43A is formed without including non-electrophoretic particles that add optical reflection characteristics. The porous layer 43B disposed on the back surface S2 side is composed of a fibrous structure including one or two or more non-electrophoretic particles, like the porous layer 33 in the above embodiment, and the electrophoretic particles 42A, It has a light reflection characteristic different from 42B.
　多孔質層４３Ａ，４３Ｂの平均孔径は、特に限定されないが、背面Ｓ２側に配置される多孔質層４３Ｂの平均孔径は、できるだけ大きいことが好ましい。泳動粒子４２Ａ，４２Ｂが細孔を通過しやすくなるからである。このため、多孔質層４３Ｂの細孔の平均孔径は、例えば、０．５μｍ以上１．５μｍ以下の範囲であることが好ましい。一方、多孔質層４３Ａの細孔の平均孔径は、粒径の大きな泳動粒子４２Ｂが通過できない孔径であることが望ましい。このため、多孔質層４３Ｂの細孔の平均孔径は、例えば、０．１μｍ以上５μｍ以下の範囲であることが好ましい。 The average pore diameter of the porous layers 43A and 43B is not particularly limited, but the average pore diameter of the porous layer 43B disposed on the back surface S2 side is preferably as large as possible. This is because the migrating particles 42A and 42B easily pass through the pores. For this reason, the average pore diameter of the pores of the porous layer 43B is preferably in the range of 0.5 μm or more and 1.5 μm or less, for example. On the other hand, it is desirable that the average pore size of the pores of the porous layer 43A is a pore size through which the large migrating particles 42B cannot pass. For this reason, it is preferable that the average pore diameter of the pores of the porous layer 43B is, for example, in the range of 0.1 μm to 5 μm.
　多孔質層４３Ａ，４３Ｂの厚みは、特に限定されないが、例えば、多孔質層４３全体の厚みは、例えば、５μｍ～１００μｍであることが好ましい。多孔質層４３の隠蔽性が高くなると共に、泳動粒子４２が細孔を通過しやすくなるからである。本変形例のように、表示面Ｓ１側に、泳動粒子４２Ｂの粒径よりも小さな平均孔径を有する多孔質層４３Ａを配置する場合には、多孔質層４３Ａの厚みは特に問わないが、多孔質層４３Ｂの厚みは、粒径の大きな泳動粒子４２Ｂを遮蔽できる厚みであることが好ましく、例えば、２μｍ以上１５μｍ以下の範囲であることが好ましい。 The thickness of the porous layers 43A and 43B is not particularly limited. For example, the thickness of the entire porous layer 43 is preferably, for example, 5 μm to 100 μm. This is because the concealability of the porous layer 43 is enhanced and the migrating particles 42 easily pass through the pores. When the porous layer 43A having an average pore size smaller than the particle size of the migrating particles 42B is arranged on the display surface S1 side as in this modification, the thickness of the porous layer 43A is not particularly limited, The thickness of the mass layer 43B is preferably a thickness that can shield the migrating particles 42B having a large particle diameter, and is preferably in the range of 2 μm to 15 μm, for example.
　多孔質層４３Ａ，４３Ｂは、帯電していると共に、互いに異なる帯電量を有する。多孔質層４３Ａ，４３Ｂは、例えば、無機顔料を含有することによって帯電させることができる。帯電量の差は、例えば、表面処理方法を変えることによって設けることができる。なお、多孔質層４３Ａおよび多孔質層４３Ｂの帯電量は、泳動粒子４２Ａおよび泳動粒子４２Ｂの帯電量との関係から決定される。また、表示面Ｓ１側に配置される多孔質層４３Ａの帯電量は、多孔質層４３Ｂの帯電量よりも小さいことが好ましい。泳動粒子４２Ａおよび泳動粒子４２Ｂの帯電量が、上記記載の範囲である場合には、多孔質層４３Ａおよび多孔質層４３Ｂの帯電量は、それぞれ、例えば、０ｍＶ以上５０ｍＶ以下（多孔質層４３Ａ）例えば、２０ｍＶ以上１００ｍＶ以下（多孔質層４３Ｂ）であることが好ましい。 The porous layers 43A and 43B are charged and have different charge amounts. The porous layers 43A and 43B can be charged, for example, by containing an inorganic pigment. The difference in charge amount can be provided, for example, by changing the surface treatment method. The charge amount of the porous layer 43A and the porous layer 43B is determined from the relationship with the charge amount of the migrating particles 42A and the migrating particles 42B. The charge amount of the porous layer 43A disposed on the display surface S1 side is preferably smaller than the charge amount of the porous layer 43B. When the charge amounts of the migrating particles 42A and the migrating particles 42B are in the above-described range, the charge amounts of the porous layer 43A and the porous layer 43B are, for example, 0 mV or more and 50 mV or less (porous layer 43A), respectively. For example, it is preferably 20 mV or more and 100 mV or less (porous layer 43B).
（２－２．作用・効果）
　以上のように、本変形例の電気泳動素子４０は、互いに平均粒径の異なる泳動粒子４２Ａ，４２Ｂと、互いに平均孔径の異なる多孔質層４３Ａ，４３Ｂとを有する。この泳動粒子４２Ａ，４２Ｂおよび多孔質層４３Ａ，４３Ｂは、帯電すると共に、互いに帯電量が異なる。具体的には、泳動粒子４２Ａよりも粒径の大きな泳動粒子４２Ｂの帯電量を大きく、多孔質層４３Ａよりも孔径の大きな多孔質層４３Ｂの帯電量を大きくするようにした。これにより、電圧印加時における泳動粒子４２Ａ，４２Ｂの移動速度の差が大きくなる。よって、表示切り替えに要する時間をさらに短縮することが可能となる。よって、表示品位のより向上した、多色表示が可能な表示装置２を提供することが可能となる。 (2-2. Action and effect)
As described above, the electrophoretic element 40 of this modification includes the electrophoretic particles 42A and 42B having different average particle diameters and the porous layers 43A and 43B having different average pore diameters. The electrophoretic particles 42A and 42B and the porous layers 43A and 43B are charged and have different charge amounts. Specifically, the charged amount of the electrophoretic particle 42B having a larger particle diameter than that of the electrophoretic particle 42A is increased, and the charged amount of the porous layer 43B having a larger pore diameter than that of the porous layer 43A is increased. Thereby, the difference in the moving speed of the migrating particles 42A and 42B at the time of voltage application is increased. Therefore, it is possible to further reduce the time required for display switching. Therefore, it is possible to provide the display device 2 capable of multicolor display with improved display quality.
　なお、本変形例の表示装置２では、互いに孔径の異なる多孔質層４３Ａ，４３Ｂを、表示面Ｓ１側に孔径の小さな多孔質層４３Ａを、背面Ｓ２側に孔径の大きな多孔質層４３Ｂを配置し、粒径の異なる泳動粒子４２Ａ，４２Ｂのうち、粒径の大きな泳動粒子４２Ｂが多孔質層４３Ａを通過できない構成としたが、上記実施の形態と同様に、表示面Ｓ１側に孔径の大きな多孔質層４３Ｂを配置するようにしてもよい。その場合には、多孔質層４３Ａは、多孔質層４３Ｂと同様の光反射特性を有することが好ましく、非泳動粒子を含んでいることが好ましい。なお、この場合には、粒径差の効果が上記実施の形態とは逆となるため、泳動粒子４２Ａ，４２Ｂの帯電差を更に大きくすることが好ましい。例えば、泳動粒子４２Ａの帯電量１０ｍＶ以上５０ｍＶ以下（多孔質層４３Ａも同じ）に対して、泳動粒子４２Ｂの帯電量は５０ｍＶ以上２５０ｍＶ以下（多孔質層４３Ｂも同じ）とすることが望ましい。 In the display device 2 of this modification, the porous layers 43A and 43B having different pore diameters are arranged, the porous layer 43A having a small pore diameter is arranged on the display surface S1, and the porous layer 43B having a large pore diameter is arranged on the back surface S2. Of the migrating particles 42A and 42B having different particle sizes, the migrating particles 42B having a large particle size cannot pass through the porous layer 43A. However, as in the above-described embodiment, the pore size is large on the display surface S1 side. You may make it arrange | position the porous layer 43B. In that case, the porous layer 43A preferably has the same light reflection characteristics as the porous layer 43B, and preferably contains non-electrophoretic particles. In this case, since the effect of the particle size difference is opposite to that in the above embodiment, it is preferable to further increase the charging difference between the migrating particles 42A and 42B. For example, it is desirable that the charge amount of the migrating particle 42B is 50 mV or more and 250 mV or less (same for the porous layer 43B) with respect to the charge amount of 10 mV or more and 50 mV or less for the migrating particle 42A (same for the porous layer 43A).
　また、本変形例では、泳動粒子４２Ａ，４２Ｂの粒径が互いに異なるようにしたが、互いに同じ粒径としてもよい。また、多孔質層４３Ａ，４３Ｂも互いに同じ孔径としてもよい。その場合には、泳動粒子４２Ａ，４２Ｂの帯電量およびその差、多孔質層４３Ａ，４３Ｂの帯電量およびその差は、上記範囲と同じでもよいが、例えば、その差を２５ｍＶ以上とすることによって、泳動粒子４２Ａ，４２Ｂおよび多孔質層４３Ａ，４３Ｂの帯電量の差のみで、多色表示が可能な表示装置を実現することが可能となる。 In this modification, the particle diameters of the migrating particles 42A and 42B are different from each other, but may be the same. The porous layers 43A and 43B may have the same pore diameter. In that case, the charge amount and the difference between the migrating particles 42A and 42B and the charge amount and the difference between the porous layers 43A and 43B may be the same as the above range. For example, by setting the difference to 25 mV or more Thus, it is possible to realize a display device capable of multicolor display only by the difference in charge amount between the migrating particles 42A and 42B and the porous layers 43A and 43B.
　図１０Ａ，１０Ｂ，１０Ｃは、互いに同じ粒径を有する泳動粒子５２Ａ，５２Ｂおよび互いに同じ孔径を有する多孔質層５３Ａ，５３Ｂからなる電気泳動素子５０における泳動粒子５２Ａ，５２Ｂの表示動作を模式的に表したものである。この表示装置３では、泳動粒子５２Ａ，５２Ｂおよび多孔質層５３Ａ，５３Ｂはそれぞれ異なる帯電量を有する。具体的には、例えば、泳動粒子５２Ａは２５ｍＶ，泳動粒子５２Ｂは１００ｍＶに、多孔質層５３Ａは０ｍＶ，多孔質層５３Ｂは１００ｍＶに帯電しているものとする。また、泳動粒子５２Ａは赤色に、泳動粒子５２Ｂは黒色に着色されるとともに、表示面Ｓ１側に配置された多孔質層５３Ａは光透過性を有するものとする。 10A, 10B, and 10C schematically show the display operation of the electrophoretic particles 52A and 52B in the electrophoretic element 50 including the electrophoretic particles 52A and 52B having the same particle diameter and the porous layers 53A and 53B having the same pore diameter. It is a representation. In the display device 3, the migrating particles 52A and 52B and the porous layers 53A and 53B have different charge amounts. Specifically, for example, the migrating particles 52A are charged to 25 mV, the migrating particles 52B are charged to 100 mV, the porous layer 53A is charged to 0 mV, and the porous layer 53B is charged to 100 mV. In addition, the migrating particles 52A are colored red, the migrating particles 52B are colored black, and the porous layer 53A disposed on the display surface S1 side is light transmissive.
　電気泳動素子５０では、図１０Ａに示したように、泳動粒子５２Ａ，５２Ｂが共に背面Ｓ２側に移動している場合には、泳動粒子５２Ａ，５２Ｂは、多孔質層５３Ｂによって隠蔽されて白表示（初期状態）となる。初期状態において、一定時間電圧を印加すると、電気泳動素子５０は、より帯電量の大きな泳動粒子５２Ｂが泳動粒子５２Ａよりも先に表示面Ｓ１に向かって移動する。但し、泳動粒子５２Ｂと多孔質層５３Ａとの電位差は大きいため、泳動粒子５２Ｂは多孔質層５３Ａを通過できず、多孔質層５３Ａと多孔質層５３Ｂの境界部分に留まる。ここで印加電圧を消去すると、図１０Ｂに示したように、泳動粒子５２Ｂは、多孔質層５３Ａと多孔質層５３Ｂの境界部分に留まったまま、泳動粒子５２Ｂよりも移動速度の小さい泳動粒子５２Ａは背面Ｓ２側（画素電極側）に戻る。これによって、電気泳動素子５０は黒表示となる。また、初期状態から黒表示時よりも長い時間電圧を印加すると、泳動粒子５２Ａおよび泳動粒子５２Ｂが共に多孔質層５３Ａと多孔質層５３Ｂの境界部分まで移動する。ここで、泳動粒子５２Ａと多孔質層５３Ａとの帯電差は比較的小さいため、泳動粒子５２Ａは、多孔質層５３Ａを通過して表示面Ｓ１に到達する。その後、印加電圧を消去すると、図１０Ｃに示したように、泳動粒子５２Ａは表示面Ｓ１に、泳動粒子５２Ｂは多孔質層５３Ａと多孔質層５３Ｂの境界部分に留まった状態となる。子によって、電気泳動素子５０は赤表示となる。 In the electrophoretic element 50, as shown in FIG. 10A, when the migrating particles 52A and 52B are both moved to the back surface S2, the migrating particles 52A and 52B are concealed by the porous layer 53B and displayed white. (Initial state). In the initial state, when a voltage is applied for a certain period of time, in the electrophoretic element 50, the electrophoretic particles 52B having a larger charge amount move toward the display surface S1 before the electrophoretic particles 52A. However, since the potential difference between the migrating particles 52B and the porous layer 53A is large, the migrating particles 52B cannot pass through the porous layer 53A and remain at the boundary between the porous layer 53A and the porous layer 53B. When the applied voltage is erased here, as shown in FIG. 10B, the migrating particle 52B remains at the boundary between the porous layer 53A and the porous layer 53B, and the migrating particle 52A has a lower moving speed than the migrating particle 52B. Returns to the back surface S2 side (pixel electrode side). As a result, the electrophoretic element 50 displays black. Further, when a voltage is applied for a longer time than when displaying black from the initial state, both the migrating particles 52A and the migrating particles 52B move to the boundary between the porous layer 53A and the porous layer 53B. Here, since the charge difference between the migrating particles 52A and the porous layer 53A is relatively small, the migrating particles 52A pass through the porous layer 53A and reach the display surface S1. Thereafter, when the applied voltage is erased, as shown in FIG. 10C, the migrating particles 52A remain on the display surface S1, and the migrating particles 52B remain on the boundary between the porous layer 53A and the porous layer 53B. The electrophoretic element 50 is displayed in red by the child.
＜３．変形例２＞
　図１１は、上記実施の形態の変形例２に係る表示装置（表示装置４）の断面構成を表したものである。この表示装置４は、電気泳動現象を利用してコントラストを生じさせ、画像を表示する表示装置、例えば電子ペーパーディスプレイ等の多様な電子機器に適用されるものである。表示装置４は、例えば、スペーサ３５を介して対向配置された駆動基板１０と対向基板２０との間に、電気泳動素子６０を含む表示層を備えたものである。電気泳動素子６０は、絶縁性液体６１中に、泳動粒子６２と複数の細孔を有する多孔質層６３とを含んで構成されている。なお、図１１は電気泳動素子６０の構成を模式的に表したものであり、実際の寸法、形状とは異なる場合がある。 <3. Modification 2>
FIG. 11 illustrates a cross-sectional configuration of a display device (display device 4) according to Modification 2 of the above embodiment. The display device 4 is applied to various electronic devices such as an electronic paper display, for example, an electronic paper display that displays an image by generating contrast using an electrophoretic phenomenon. The display device 4 includes, for example, a display layer including the electrophoretic element 60 between the drive substrate 10 and the counter substrate 20 that are disposed to face each other with the spacer 35 interposed therebetween. The electrophoretic element 60 is configured to include an electrophoretic particle 62 and a porous layer 63 having a plurality of pores in an insulating liquid 61. Note that FIG. 11 schematically shows the configuration of the electrophoretic element 60 and may differ from the actual size and shape.
（３－１．電気泳動素子の構成）
　本変形例の電気泳動素子６０は、泳動粒子６２として、互いに異なる平均粒径を有する複数種類の泳動粒子（例えば、互いに平均粒径の異なる泳動粒子６２Ａおよび泳動粒子６２Ｂ）を有する。また、電気泳動素子６０は、多孔質層６３として、互いに平均孔径の異なる複数種類の多孔質層を有する。具体的には、多孔質層６３は、例えば、３層の多孔質層６３Ａ，６３Ｂ，６３Ｃを有し、多孔質層６３Ｂは、多孔質層６３Ａよりの大きな平均孔径を有する。本変形例では、平均孔径の小さな多孔質層６３Ａが表示面Ｓ１側に、多孔質層６３Ａよりも平均孔径の大きな多孔質層６３Ｂが背面Ｓ２側に配置されると共に、互いに光透過性を有する点が上記実施の形態および変形例１とは異なる。また、本変形例の表示装置４は、さらに、多孔質層６３Ｂの背面Ｓ２側に光学的反射特性を有する多孔質層６３Ｃが配置された構成を有する。 (3-1. Configuration of electrophoretic element)
The electrophoretic element 60 of this modification has a plurality of types of electrophoretic particles having different average particle diameters (for example, electrophoretic particles 62A and electrophoretic particles 62B having different average particle diameters) as the electrophoretic particles 62. In addition, the electrophoretic element 60 has a plurality of types of porous layers having different average pore diameters as the porous layer 63. Specifically, the porous layer 63 includes, for example, three porous layers 63A, 63B, and 63C, and the porous layer 63B has a larger average pore diameter than the porous layer 63A. In the present modification, the porous layer 63A having a small average pore diameter is disposed on the display surface S1 side, and the porous layer 63B having a larger average pore diameter than the porous layer 63A is disposed on the back surface S2 side, and has light transmission properties. This is different from the above embodiment and the first modification. Further, the display device 4 of the present modification further has a configuration in which a porous layer 63C having optical reflection characteristics is disposed on the back surface S2 side of the porous layer 63B.
　絶縁性液体６１は、上記実施の形態と同様に、例えば、有機溶媒等の非水溶媒のいずれか１種類または２種類以上であり、具体的には、パラフィンまたはイソパラフィン等を含んで構成されている。この絶縁性液体６１の粘度および屈折率は、出来るだけ低いことが好ましい。泳動粒子６２の移動性（応答速度）が向上すると共に、それに応じて泳動粒子６２の移動に要するエネルギー（消費電力）が低くなるからである。また、絶縁性液体６１の屈折率と多孔質層６３の屈折率との差が大きくなるため、その多孔質層６３の光反射率が高くなるからである。なお、絶縁性液体６１の代わりに、微弱導電性液体を用いてもよい。また、絶縁性液体６１は、必要に応じて各種材料（例えば、着色剤、電荷制御剤、分散安定剤、粘度調整剤、界面活性剤または樹脂等）を含んでいてもよい。 As in the above embodiment, the insulating liquid 61 is, for example, any one type or two or more types of non-aqueous solvents such as organic solvents, and specifically includes paraffin or isoparaffin. Yes. It is preferable that the viscosity and refractive index of the insulating liquid 61 be as low as possible. This is because the mobility (response speed) of the migrating particles 62 is improved, and the energy (power consumption) required to move the migrating particles 62 is lowered accordingly. Moreover, since the difference between the refractive index of the insulating liquid 61 and the refractive index of the porous layer 63 becomes large, the light reflectance of the porous layer 63 becomes high. Note that a weak conductive liquid may be used instead of the insulating liquid 61. The insulating liquid 61 may contain various materials (for example, a colorant, a charge control agent, a dispersion stabilizer, a viscosity modifier, a surfactant, or a resin) as necessary.
　泳動粒子６２は、電気的に移動可能な１または２以上の荷電粒子であり、絶縁性液体６１中に分散されている。本変形例における泳動粒子６２は、上記のように、互いに平均粒径の異なる泳動粒子６２Ａ，６２Ｂを有し、それぞれ１または２以上の荷電粒子で構成されている。更に、泳動粒子６２Ａ，６２Ｂは、異なる色に着色されている。具体的には、泳動粒子６２Ａは、例えば赤色（Ｒ）に、泳動粒子６２Ｂは、例えば黒色（Ｂ）に着色されている。泳動粒子６２の粒径は、例えば、０．１μｍ以上２μｍ以下の範囲であることが好ましく、泳動粒子６２Ａ，６２Ｂは、この範囲内で、例えば、０．３μｍ（泳動粒子６２Ａ），０．２μｍ（泳動粒子６２Ｂ）となっている。なお、各泳動粒子６２Ａ，６２Ｂの平均粒径は上記範囲に限定されるものではなく、例えば、平均粒径が０．１μｍ以上であれば良い。 The electrophoretic particles 62 are one or more charged particles that are electrically movable and are dispersed in the insulating liquid 61. As described above, the migrating particle 62 in the present modification includes the migrating particles 62A and 62B having different average particle diameters, and each is composed of one or more charged particles. Furthermore, the migrating particles 62A and 62B are colored in different colors. Specifically, the migrating particles 62A are colored, for example, red (R), and the migrating particles 62B are colored, for example, black (B). The particle size of the migrating particles 62 is preferably in the range of 0.1 μm to 2 μm, for example, and the migrating particles 62A and 62B are within this range, for example, 0.3 μm (migrating particles 62A) and 0.2 μm. (Electrophoretic particle 62B). In addition, the average particle diameter of the migrating particles 62A and 62B is not limited to the above range, and for example, the average particle diameter may be 0.1 μm or more.
　泳動粒子６２Ａ，６２Ｂは、上記実施の形態における泳動粒子６２と同様に、例えば、有機顔料、無機顔料、染料、炭素材料、金属材料、金属酸化物、ガラスまたは高分子材料（樹脂）等のいずれか１種類または２種類以上の粒子（粉末）である。 The migrating particles 62A and 62B are, for example, any of organic pigments, inorganic pigments, dyes, carbon materials, metal materials, metal oxides, glass, polymer materials (resins), and the like, similar to the migrating particles 62 in the above embodiment. Or one kind or two or more kinds of particles (powder).
　絶縁性液体６１中における泳動粒子６２Ａ，６２Ｂの含有量（濃度）は、特に限定されないが、泳動粒子６２全体では、例えば、０．１重量％～１０重量％であることが好ましい。泳動粒子３２による多孔質層３３の遮蔽性、多孔質層３３による泳動粒子３２の隠蔽性および移動性が確保されるからである。０．１重量％よりも少ないと、泳動粒子６２が多孔質層６３を遮蔽しにくくなる可能性がある。一方、１０重量％よりも多いと、泳動粒子６２の分散性が低下するため、泳動粒子６２が泳動しにくくなり、場合によっては凝集する可能性がある。泳動粒子６２Ａ，６２Ｂは、粒径や表面修飾あるいは材質にもよるが、例えば、泳動粒子６２Ａおよび泳動粒子６２Ｂ共に、０．１重量％～４重量％であることが好ましい。 The content (concentration) of the migrating particles 62A and 62B in the insulating liquid 61 is not particularly limited, but the entire migrating particle 62 is preferably, for example, 0.1 wt% to 10 wt%. This is because the shielding property of the porous layer 33 by the migrating particles 32 and the concealing property and mobility of the migrating particles 32 by the porous layer 33 are ensured. If the amount is less than 0.1% by weight, the migrating particles 62 may not easily shield the porous layer 63. On the other hand, when the content is more than 10% by weight, the dispersibility of the migrating particles 62 is lowered, so that the migrating particles 62 are difficult to migrate, and there is a possibility that the migrating particles 62 may aggregate. For example, both the migrating particles 62A and the migrating particles 62B are preferably 0.1% by weight to 4% by weight although the migrating particles 62A and 62B depend on the particle size, surface modification, or material.
　本変形例における泳動粒子６２Ａ，６２Ｂは、同一極性に帯電していると共に、互いに異なる平均移動速度を有し、例えば泳動粒子６２Ａの平均移動速度は、泳動粒子６２Ｂの平均移動速度よりも小さい。この平均移動速度の違いは、例えば泳動粒子６２Ａ，６２Ｂが有する帯電量によって決定される。帯電量の差は、上記変形例１と同様に、例えば、表面処理を行うことによって付加することができる。具体的には、例えば、泳動粒子６２Ａ，６２Ｂが、それぞれ負の電荷を有する場合には、例えば、異なる電荷量を有する電子吸引性を有する官能基を修飾することで帯電差を設けることができる。また、泳動粒子６２Ａ，６２Ｂが、それぞれ正の電荷を有する場合には、例えば、それぞれ異なる電荷量を有する電子供与性を有する官能基を修飾することで帯電差を設けることができる。なお、泳動粒子６２Ａ，６２Ｂの表面に修飾させる官能基の量を変えることでも帯電差を設けることができる。 The migrating particles 62A and 62B in the present modification are charged with the same polarity and have different average moving speeds. For example, the average moving speed of the migrating particles 62A is smaller than the average moving speed of the migrating particles 62B. The difference in the average moving speed is determined by, for example, the charge amount possessed by the migrating particles 62A and 62B. The difference in charge amount can be added, for example, by performing a surface treatment as in the first modification. Specifically, for example, when the migrating particles 62A and 62B each have a negative charge, for example, a charge difference can be provided by modifying an electron-withdrawing functional group having a different charge amount. . In addition, when the migrating particles 62A and 62B have positive charges, for example, a charge difference can be provided by modifying functional groups having electron donating properties having different charge amounts. The charging difference can also be provided by changing the amount of the functional group to be modified on the surfaces of the migrating particles 62A and 62B.
　多孔質層６３は、上記実施の形態と同様に、例えば、図２に示したような繊維状構造体（繊維状構造体３３１）により形成された３次元立体構造物（不織布のような不規則なネットワーク構造物）である。本変形例における多孔質層６３は、互いに孔径の異なると共に、光透過性を有する２種類の多孔質層６３Ａおよび多孔質層６３Ｂと、光学的反射特性を有する多孔質層６３Ｃとから構成されている。光透過性を有する多孔質層６３Ａおよび多孔質層６３Ｂの積層順は、表示面Ｓ１側に細孔の平均孔径の小さな多孔質層６３Ａが、背面Ｓ２側に細孔の平均孔径が大きな多孔質層６３Ｂが配置されている。光学的反射特性（光反射率）を有する多孔質層６３Ｃは、多孔質層６３Ｂの背面Ｓ２側に配置されている。 As in the above embodiment, the porous layer 63 is, for example, a three-dimensional structure (irregularity such as a nonwoven fabric) formed by a fibrous structure (fibrous structure 331) as shown in FIG. Network structure). The porous layer 63 in the present modification is composed of two kinds of porous layers 63A and 63B having different light diameters and having light transmission properties, and a porous layer 63C having optical reflection characteristics. Yes. The order of lamination of the light-transmitting porous layer 63A and porous layer 63B is such that the porous layer 63A having a small average pore diameter on the display surface S1 side and the pore having a large average pore diameter on the back surface S2 side. Layer 63B is disposed. The porous layer 63C having optical reflection characteristics (light reflectance) is disposed on the back surface S2 side of the porous layer 63B.
　多孔質層６３を構成する材料としては、上記実施の形態において挙げた材料を用いることができる。但し、光透過性を有する多孔質層６３Ａ，６３Ｂは、図２に示したような非泳動粒子（非泳動粒子３３２）を含まない繊維状構造体によって構成されている。背面Ｓ２側に配置されている多孔質層６３Ｃは、上記実施の形態における多孔質層６３と同様に、１または２以上の非泳動粒子を含む繊維状構造体によって構成されており、泳動粒子６２Ａ，６２Ｂとは異なる光反射率を有する。なお、多孔質層６３Ａ，６３Ｂは、可視光を反射しない粒子（非可視光粒子）を含んでいることが好ましい。可視光を反射しない粒子とは、例えば、粒径２５０ｎｍ以下のチタニア（ＴｉＯ2）が挙げられる。ＴｉＯ2を含有させた繊維状構造体を用いて多孔質層６３Ａ，６３Ｂを構成することにより、多孔質層６３Ａ，６３Ｂ内における泳動粒子６２Ａ，６２Ｂの保持性能が向上する可能性があるからである。 As a material constituting the porous layer 63, the materials mentioned in the above embodiment can be used. However, the light-transmitting porous layers 63A and 63B are composed of a fibrous structure that does not include non-electrophoretic particles (non-electrophoretic particles 332) as shown in FIG. The porous layer 63C disposed on the back surface S2 side is composed of a fibrous structure including one or two or more non-electrophoretic particles, like the porous layer 63 in the above embodiment, and the electrophoretic particles 62A. , 62B have different light reflectivity. The porous layers 63A and 63B preferably contain particles that do not reflect visible light (non-visible light particles). Examples of the particles that do not reflect visible light include titania (TiO 2 ) having a particle size of 250 nm or less. This is because the holding performance of the migrating particles 62A and 62B in the porous layers 63A and 63B may be improved by forming the porous layers 63A and 63B using the fibrous structure containing TiO 2. is there.
　多孔質層６３Ａ，６３Ｂの平均孔径は、それぞれ泳動粒子６２Ａ，６２Ｂによって決定される。具体的には、多孔質層６３Ａの細孔の平均孔径は、泳動粒子６２Ｂは通過できるが、より平均粒径の大きな泳動粒子６２Ａが通過できない孔径であることが好ましく、例えば、０．３μｍ未満であることが好ましい。多孔質層６３Ｂの平均孔径は、泳動粒子６２Ａおよび泳動粒子６２Ｂが通過できればよく、特に限定されないが、できるだけ大きいことが好ましい。泳動粒子６２Ａ，６２Ｂが細孔を通過しやすくなるからである。このため、多孔質層６３Ｂの細孔の平均孔径は、例えば、０．３μｍ以上５μｍ以下の範囲であることが好ましい。また、多孔質層６３Ｃの平均孔径は、泳動粒子６２Ａおよび泳動粒子６２Ｂが通過できればよく、多孔質層６３Ｂと同じ平均孔径でもよいし、より大きな平均孔径でも構わない。 The average pore sizes of the porous layers 63A and 63B are determined by the migrating particles 62A and 62B, respectively. Specifically, the average pore diameter of the pores of the porous layer 63A is preferably a pore diameter that allows the migrating particles 62B to pass through but does not allow the migrating particles 62A having a larger average particle diameter to pass through, for example, less than 0.3 μm. It is preferable that The average pore size of the porous layer 63B is not particularly limited as long as the migrating particles 62A and the migrating particles 62B can pass through, but is preferably as large as possible. This is because the migrating particles 62A and 62B easily pass through the pores. For this reason, it is preferable that the average pore diameter of the pores of the porous layer 63B is, for example, in the range of 0.3 μm to 5 μm. Further, the average pore size of the porous layer 63C only needs to allow the migrating particles 62A and the migrating particles 62B to pass through, and may be the same average pore size as the porous layer 63B or a larger average pore size.
　多孔質層６３全体の厚みは、特に限定されないが、例えば、５μｍ～１００μｍであることが好ましい。多孔質層６３全体に対する多孔質層６３Ａ、多孔質層６３Ｂおよび多孔質層６３Ｃの厚みは、例えば以下のように決定される。まず、光透過性を有する多孔質層（多孔質層６３Ａおよび多孔質層６３Ｂ）の厚み（Ｗ１（多孔質層６３Ａ）およびＷ２（多孔質層６３Ｂ））は、より移動速度の速い泳動粒子６２Ｂの平均泳動速度をＶ１、泳動粒子６２Ａの平均泳動速度をＶ２、多孔質層６３全体の厚みをＷとした場合、（Ｗ１＋Ｗ２）＝Ｗ×（Ｖ２／Ｖ１）であることが好ましい。多孔質層６３Ａおよび多孔質層６３Ｂのそれぞれの厚みは、Ｗ１，Ｗ２＝０．５×Ｗ×（Ｖ２／Ｖ１）とする。光反射特性を有する多孔質層６３Ｃの厚み（Ｗ３）は、多孔質層６３全体の厚み（Ｗ）から多孔質層６３Ａおよび多孔質層６３Ｂの厚み（Ｗ１＋Ｗ２）を差し引いた厚みとなる。 The thickness of the entire porous layer 63 is not particularly limited, but is preferably 5 μm to 100 μm, for example. The thicknesses of the porous layer 63A, the porous layer 63B, and the porous layer 63C with respect to the entire porous layer 63 are determined as follows, for example. First, the thickness (W1 (porous layer 63A) and W2 (porous layer 63B)) of the light-transmitting porous layers (porous layer 63A and porous layer 63B) is such that migrating particles 62B having a higher moving speed. In this case, it is preferable that (W1 + W2) = W × (V2 / V1), where V1 is the average migration speed of V2, V2 is the average migration speed of the migrating particles 62A, and W is the total thickness of the porous layer 63. The thicknesses of the porous layer 63A and the porous layer 63B are W1, W2 = 0.5 × W × (V2 / V1). The thickness (W3) of the porous layer 63C having light reflection characteristics is a thickness obtained by subtracting the thickness (W1 + W2) of the porous layer 63A and the porous layer 63B from the thickness (W) of the entire porous layer 63.
（３－２．作用・効果）
　以上のように、本変形例の電気泳動素子６０では、表示面Ｓ１側に光透過性を有する多孔質層６３Ａおよび多孔質層６３Ｂを設け、表示面Ｓ１側に平均孔径が小さな多孔質層６３Ａを、背面Ｓ２側に、多孔質層６３Ａよりも平均孔径の大きな多孔質層６３Ｂを配置するようにした。更に、多孔質層６３Ｂの背面Ｓ２側には、光反射性を有する多孔質層６３Ｃを配置するようにした。電気泳動素子６０では、泳動粒子６２として、泳動粒子６２Ａおよび泳動粒子６２Ａよりも粒径の小さな泳動粒子６２Ｂを用いるようにした。泳動粒子６２Ａ，６２Ｂの平均粒径および多孔質層６３Ａ，６３Ｂ，６３Ｃの平均孔径は、それぞれ泳動粒子６２Ｂは多孔質層６３Ａの細孔を通過できるものの、泳動粒子６２Ａは多孔質層６３Ａの細孔を通過できない大きさとした。多孔質層６３Ｂおよび多孔質層６３Ｃの細孔は、泳動粒子６２Ａおよび泳動粒子６２Ｂの両方が通過可能な大きさとした。 (3-2. Action and effect)
As described above, in the electrophoretic element 60 of this modification, the porous layer 63A and the porous layer 63B having light transmittance are provided on the display surface S1 side, and the porous layer 63A having a small average pore diameter is provided on the display surface S1 side. The porous layer 63B having a larger average pore diameter than the porous layer 63A is arranged on the back surface S2 side. Further, a porous layer 63C having light reflectivity is disposed on the back surface S2 side of the porous layer 63B. In the electrophoretic element 60, the electrophoretic particles 62A and the electrophoretic particles 62B having a smaller particle diameter than the electrophoretic particles 62A are used as the electrophoretic particles 62. The average particle size of the migrating particles 62A and 62B and the average pore size of the porous layers 63A, 63B, and 63C are such that the migrating particles 62B can pass through the pores of the porous layer 63A, but the migrating particles 62A are fine particles of the porous layer 63A. The size is such that it cannot pass through the hole. The pores of the porous layer 63B and the porous layer 63C are sized so that both the migrating particles 62A and the migrating particles 62B can pass through.
　本変形例の表示装置４は、上記実施の形態と同様に、画素電極１４と対向電極２２との間に印加される電圧の印加時間を制御することにより、画素電極１４と対向電極２２との間における泳動粒子６２Ａ（赤色；Ｒ），６２Ｂ（黒色；Ｂ）の平均分布位置を制御し、赤表示（Ｒ）、黒表示（Ｂ）および白表示（Ｗ）を切り替えることができる。泳動粒子６２Ａおよび泳動粒子６２Ｂは、それぞれ帯電しており、画素電極１４と対向電極２２との間に印加される電界と時間によって所望の泳動粒子６２Ａおよび泳動粒子６２Ｂの分布を制御することができる。表示装置４では、泳動粒子６２Ａ，６２Ｂが、それぞれ光透過性を有する多孔質層６３Ａまたは多孔質層６３Ｂ中に分布するか、あるいは、光反射性を有する多孔質層６３Ｃの表示面Ｓ１側に近づくことで、表示面からは、泳動粒子６２Ａおよび泳動粒子６２Ｂの色が視認される。表示装置４では、泳動粒子６２Ａ，６２Ｂが、多孔質層６３Ｃ中（背面Ｓ２側）に移動することによって多孔質層７３Ｃに隠蔽され、表示面からは、多孔質層６３Ｃからの拡散光が視認される。 In the display device 4 of the present modification, the application time of the voltage applied between the pixel electrode 14 and the counter electrode 22 is controlled as in the above embodiment, so that the pixel electrode 14 and the counter electrode 22 The average distribution position of the migrating particles 62A (red; R) and 62B (black; B) can be controlled to switch between red display (R), black display (B), and white display (W). The electrophoretic particles 62A and the electrophoretic particles 62B are charged, and the distribution of the desired electrophoretic particles 62A and electrophoretic particles 62B can be controlled by the electric field and time applied between the pixel electrode 14 and the counter electrode 22. . In the display device 4, the migrating particles 62A and 62B are distributed in the light-transmitting porous layer 63A or the porous layer 63B, respectively, or on the display surface S1 side of the light-reflecting porous layer 63C. By approaching, the colors of the migrating particles 62A and the migrating particles 62B are visually recognized from the display surface. In the display device 4, the migrating particles 62 </ b> A and 62 </ b> B are hidden in the porous layer 73 </ b> C by moving into the porous layer 63 </ b> C (back S <b> 2 side), and diffused light from the porous layer 63 </ b> C is visually recognized from the display surface. Is done.
　図１１は、表示装置４の駆動方法の一例としての背面Ｓ２側の表示面Ｓ１側に対する電位差の時間変化を表したものである。図１２は、図１１に示した背面Ｓ２側の表示面Ｓ１側に対する電位差の時間変化による泳動粒子６２Ａ（赤色；Ｒ），６２Ｂ（黒色；Ｂ）の平均分布位置（平均移動位置）の時間変化を表したものである。各泳動粒子６２Ａ，６２Ｂは、それぞれ正（＋）に帯電すると共に、表１に示した泳動速度を有するものとする。 FIG. 11 shows the change over time of the potential difference with respect to the display surface S1 side on the back surface S2 side as an example of the driving method of the display device 4. FIG. 12 shows the time change of the average distribution position (average movement position) of the migrating particles 62A (red; R) and 62B (black; B) due to the time change of the potential difference with respect to the display surface S1 side on the back surface S2 side shown in FIG. It represents. The electrophoretic particles 62A and 62B are charged positively (+) and have the electrophoretic speed shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　まず、全ての泳動粒子６２Ａ，６２Ｂを背面Ｓ２側に移動させる。このとき、表示面Ｓ１は白表示となる（起点０秒）。背面Ｓ２側の電位を高くすると、正に帯電している泳動粒子６２Ａ，６２Ｂは、表示面Ｓ１側に移動し始め、泳動速度の速い泳動粒子６２Ｂが表示面Ｓ１に到達した時点で電位差を０にする。このとき、泳動速度が遅い泳動粒子６２Ａは、非泳動粒子によって白色を呈する多孔質層６３Ｃ中に位置するため、泳動粒子６２Ａは多孔質層６３Ｃによって隠蔽される。これにより、表示面Ｓ１の表示色は黒色（Ｂ）になる。 First, all the migrating particles 62A and 62B are moved to the back surface S2. At this time, the display surface S1 is displayed in white (starting point 0 seconds). When the potential on the back surface S2 side is increased, the positively charged migrating particles 62A and 62B begin to move toward the display surface S1, and the potential difference is reduced to 0 when the migrating particle 62B having a fast migrating speed reaches the display surface S1. To. At this time, since the migrating particles 62A having a low migrating speed are located in the porous layer 63C that is white due to the non-migrating particles, the migrating particles 62A are concealed by the porous layer 63C. Thereby, the display color of the display surface S1 becomes black (B).
　続いて、背面Ｓ２側の電位を高くすると、表示面Ｓ１と背面Ｓ２との間（多孔質層６３Ｃ中）にとどまっていた泳動粒子６２Ａが表示面Ｓ１に向かって移動する。泳動粒子６２Ａが光透過性を有する多孔質層６３Ａと多孔質層６３Ｂとの界面に到達した時点で背面Ｓ２側の電位を反転させ、表示面Ｓ１に対して電位を低くすると、泳動速度の速い泳動粒子６２Ｂが泳動粒子６２Ａよりも早く背面Ｓ２側に移動する。泳動粒子６２Ｂが背面Ｓ２に到達した時点で電位差を０にすると、泳動粒子６２Ｂは、光反射性を有する多孔質層６３Ｃ内に分布することになり、多孔質層６３Ｃによって隠蔽される。この移動時に、泳動粒子６２Ａは、背面Ｓ２側に向かって移動するが、その移動速度は遅く、また、光透過性を有する多孔質層６３Ｂが配置されているため、泳動粒子６２Ａの彩度（赤色）は確保される。これにより、表示面Ｓ１の表示色は赤色（Ｒ）となる。更に、背面Ｓ２側の電位を、表示面Ｓ１に対して低くすると、多孔質層６３Ｂにとどまっていた泳動粒子６２Ａが背面Ｓ２側に移動する。泳動粒子６２Ａが背面Ｓ２に到達した時点で電位差を０にすると、泳動粒子６２Ａ，６２Ｂが共に多孔質層６３Ｃによって隠蔽されることとなり、表示色は白色（Ｗ）となる。 Subsequently, when the potential on the back surface S2 side is increased, the migrating particles 62A staying between the display surface S1 and the back surface S2 (in the porous layer 63C) move toward the display surface S1. When the migrating particles 62A reach the interface between the porous layer 63A and the porous layer 63B having optical transparency, the potential on the back surface S2 side is reversed and the potential is lowered with respect to the display surface S1, so that the migration speed is high. The migrating particle 62B moves to the back surface S2 side earlier than the migrating particle 62A. When the potential difference is set to 0 when the migrating particles 62B reach the back surface S2, the migrating particles 62B are distributed in the light-reflecting porous layer 63C and are hidden by the porous layer 63C. During this movement, the migrating particle 62A moves toward the back surface S2, but its moving speed is slow, and since the porous layer 63B having light permeability is disposed, the saturation ( Red) is secured. Thereby, the display color of the display surface S1 is red (R). Further, when the potential on the back surface S2 side is lowered with respect to the display surface S1, the migrating particles 62A staying on the porous layer 63B move to the back surface S2 side. If the potential difference is set to 0 when the migrating particles 62A reach the back surface S2, both the migrating particles 62A and 62B are concealed by the porous layer 63C, and the display color is white (W).
　図１４は、一般的な表示装置の駆動方法の一例としての背面Ｓ２側の表示面Ｓ１側に対する電位差の時間変化を表したものである。一般的な表示装置とは、泳動粒子として、赤色に着色された泳動粒子（赤色泳動粒子；Ｒ）および黒色に着色された泳動粒子（黒色泳動粒子；Ｂ）を備え、多孔質層として、光透過性を有する多孔質層および光反射性を有する多孔質層をそれぞれ１層ずつ積層したものである。２層の多孔質層は、共に、赤色泳動粒子および黒色泳動粒子が通過できる孔径の細孔を有する。図１５は、図１４に示した背面Ｓ２側の表示面Ｓ１側に対する電位差の時間変化による赤色泳動粒子および黒色泳動粒子の平均分布位置（平均移動位置）の時間変化を表したものである。赤色泳動粒子および黒色泳動粒子は、本変形例と同様に、それぞれ正（＋）に帯電すると共に、表２に示した泳動速度を有するものとする。 FIG. 14 shows a change with time of a potential difference with respect to the display surface S1 side on the back surface S2 side as an example of a driving method of a general display device. A general display device includes electrophoretic particles that are colored in red (red electrophoretic particles; R) and electrophoretic particles that are colored black (black electrophoretic particles; B). A porous layer having transparency and a porous layer having light reflectivity are laminated one by one. Both of the two porous layers have pores having a pore diameter through which red electrophoretic particles and black electrophoretic particles can pass. FIG. 15 shows the change over time of the average distribution position (average moving position) of the red migrating particles and the black migrating particles due to the time change of the potential difference with respect to the display surface S1 side on the back surface S2 side shown in FIG. The red electrophoretic particles and the black electrophoretic particles are charged positively (+), respectively, and have the electrophoretic speeds shown in Table 2 as in this modification.
　図１２，１３と、図１４，１５とを比較すると、一般的な表示装置では、本変形例の表示装置４よりも表示色の切り替えに時間を要することがわかる。これは、表示装置４と比較して、移動速度の遅い赤色泳動粒子の移動距離が大きいからである。即ち、本変形例では、複数の多孔質層を、背面Ｓ２から表示面Ｓ１に向かって平均孔径が小さくなるように積層した。具体的には、表示面Ｓ１側に、泳動粒子６２Ａの平均粒径以下の孔径を有する多孔質層６３Ａを配置するようにしたので、泳動粒子６２Ａの移動距離が短縮され、その分高速な表示色（本変形例では、黒色（Ｂ）、赤色（Ｒ）および白色（Ｗ））の切り替えが可能となる。 12 and 13 are compared with FIGS. 14 and 15, it can be seen that a general display device requires more time for switching the display color than the display device 4 of the present modification. This is because the moving distance of the red migrating particles having a slower moving speed is larger than that of the display device 4. That is, in this modification, a plurality of porous layers are stacked so that the average pore diameter decreases from the back surface S2 toward the display surface S1. Specifically, since the porous layer 63A having a pore diameter equal to or smaller than the average particle diameter of the migrating particles 62A is disposed on the display surface S1, the moving distance of the migrating particles 62A is shortened, and the display speed is increased accordingly. Colors (black (B), red (R), and white (W) in this modification) can be switched.
＜３．適用例＞
　次に、上記実施の形態の表示装置１～４の適用例について説明する。但し、以下で説明する電子機器の構成はあくまで一例であるため、その構成は適宜変更可能である。 <3. Application example>
Next, application examples of the display devices 1 to 4 of the above embodiment will be described. However, the configuration of the electronic device described below is merely an example, and the configuration can be changed as appropriate.
（適用例１）
　図１６Ａ，１６Ｂは、電子ブックの外観構成を表している。この電子ブックは、例えば、表示部１１０および非表示部１２０と、操作部１３０とを備えている。なお、操作部１３０は、図１６Ａに示したように非表示部１２０の前面に設けられていてもよいし、図１６Ｂに示したように上面に設けられていてもよい。表示部１１０が表示装置１（あるいは、２，３）により構成される。なお、表示装置１（あるいは、表示装置２～４）は、図１６Ａ，１６Ｂに示した電子ブックと同様の構成を有するＰＤＡ（Personal Digital Assistants）等に搭載されてもよい。 (Application example 1)
16A and 16B show the external configuration of an electronic book. The electronic book includes, for example, a display unit 110, a non-display unit 120, and an operation unit 130. Note that the operation unit 130 may be provided on the front surface of the non-display unit 120 as illustrated in FIG. 16A, or may be provided on the upper surface as illustrated in FIG. 16B. The display unit 110 is configured by the display device 1 (or 2, 3). The display device 1 (or the display devices 2 to 4) may be mounted on a PDA (Personal Digital Assistants) having the same configuration as the electronic book shown in FIGS. 16A and 16B.
（適用例２）
　図１７は、タブレットパーソナルコンピュータの外観を表したものである。このタブレットパーソナルコンピュータは、例えば、タッチパネル部２１０および筐体２２０を有しており、タッチパネル部２１０が上記表示装置１（あるいは、表示装置２～４）により構成されている。 (Application example 2)
FIG. 17 shows the appearance of a tablet personal computer. The tablet personal computer has, for example, a touch panel unit 210 and a housing 220, and the touch panel unit 210 is constituted by the display device 1 (or display devices 2 to 4).
　また、上記実施の形態および変形例の表示装置１～４は、電子掲示板等に適用してもよい。 Further, the display devices 1 to 4 of the above-described embodiments and modifications may be applied to an electronic bulletin board or the like.
　以上、実施の形態および変形例１，２を挙げて説明したが、本開示内容は実施形態等で説明した態様に限定されず、種々の変形が可能である。例えば、上記実施の形態等では、互いに粒径の異なる泳動粒子３２の種類および互いに細孔３３３の孔径の異なる多孔質層３３の種類をそれぞれ同数用いて構成したが、これに限らず、異なっていてもよい。例えば、互いに細孔３３３の孔径の異なる多孔質層３３を、互いに粒径の異なる泳動粒子３２の種類より多い層数を積層するようにしてもよい。 As described above, the embodiment and modifications 1 and 2 have been described, but the present disclosure is not limited to the aspects described in the embodiment and the like, and various modifications are possible. For example, in the above-described embodiment and the like, the same number of types of migrating particles 32 having different particle sizes and the same number of types of porous layers 33 having different pore sizes of the pores 333 are used. May be. For example, the porous layers 33 having different pore diameters of the pores 333 may be stacked with a larger number of layers than the types of the migrating particles 32 having different particle diameters.
　また、上記実施の形態等では、電気泳動素子３０（表示層）として、絶縁性液体３１、泳動粒子３２および多孔質層３３を備えた構成を例示したが、電気泳動素子３０の構成は、このような多孔質層３３を用いたものに限定されず、電気泳動現象を利用して画素毎に光反射によるコントラスト形成が可能なものであればよい。 Moreover, in the said embodiment etc., although the structure provided with the insulating liquid 31, the electrophoretic particle 32, and the porous layer 33 was illustrated as the electrophoretic element 30 (display layer), the structure of the electrophoretic element 30 is this. It is not limited to the one using the porous layer 33 as long as it can form a contrast by light reflection for each pixel using the electrophoresis phenomenon.
　更に、例えば、変形例２に変形例１を組み合わせて、例えば、多孔質層６３を帯電させるようにしてもよい。 Further, for example, the modification 1 may be combined with the modification 2 to charge the porous layer 63, for example.
　なお、本明細書中に記載された効果はあくまで例示であって限定されるものではなく、また、他の効果があってもよい。 In addition, the effect described in this specification is an illustration to the last, and is not limited, Moreover, there may exist another effect.
　なお、本開示は以下のような構成を取ることも可能である。
（１）
　互いに平均粒径の異なる複数種類の泳動粒子と、
　繊維状構造体により形成されると共に、互いに平均孔径が異なる複数の多孔質層と
　を備えた表示装置。
（２）
　表示面を有し、前記複数の多孔質層は互いに積層されており、前記表示面から背面に向かって平均孔径が小さくなっていく、前記（１）に記載の表示装置。
（３）
　前記複数種類の泳動粒子は、互いに異なる色を有する、前記（１）または（２）に記載の表示装置。
（４）
　前記複数の多孔質層の層数は、前記泳動粒子の種類と同数以上である、前記（１）乃至（３）のうちのいずれかに記載の表示装置。
（５）
　前記複数の多孔質層は、前記表示面側から第１層および前記第１層よりも平均孔径の小さな第２層を有し、
　前記第１層の厚みは、前記第２層よりも大きい、前記（２）乃至（４）のうちのいずれかに記載の表示装置。
（６）
　前記複数種類の泳動粒子はそれぞれ帯電すると共に、互いに帯電量が異なる、前記（１）乃至（５）のうちのいずれかに記載の表示装置。
（７）
　前記複数の多孔質層はそれぞれ帯電すると共に、互いに帯電量が異なる、前記（１）乃至（６）のうちのいずれかに記載の表示装置。
（８）
　前記複数種類の泳動粒子の平均粒径は、１００ｎｍ以上２μｍ以下である、前記（１）乃至（７）のうちのいずれかに記載の表示装置。
（９）
　前記複数の多孔質層の平均孔径は、０．１μｍ以上５μｍ以下である、前記（１）乃至（８）のうちのいずれかに記載の表示装置。
（１０）
　前記多孔質層は、前記繊維状構造体に保持された非泳動粒子を有し、
　前記非泳動粒子の光反射率は前記泳動粒子の光反射率よりも高く、前記泳動粒子が暗表示、前記非泳動粒子および繊維状構造体が明表示を行う、前記（１）乃至（９）のうちのいずれかに記載の表示装置。
（１１）
　前記泳動粒子および前記非泳動粒子は、有機顔料，無機顔料，染料，炭素材料，金属材料，金属酸化物，ガラスおよび高分子材料のうちの少なくともいずれか１つにより構成されている、前記（１０）に記載の表示装置。
（１２）
　表示面を有し、前記複数の多孔質層は、背面から前記表示面に向かって平均孔径が小さくなっていく積層構造を有する、前記（１）、（３）、（４）、（６）乃至（９）のうちのいずれか１に記載の表示装置。
（１３）
　前記複数の多孔質層は、前記表示面側から第３層および前記第３層よりも平均孔径の大きな第４層を有し、
　前記第３層および前記第４層は、それぞれ光透過性を有する、前記（１２）に記載の表示装置。
（１４）
　前記複数の多孔質層は、前記第４層の背面側にさらに第５層を有し、
　前記第５層は、前記複数種類の泳動粒子とは異なる光学的反射特性を有する、前記（１３）に記載の表示装置。
（１５）
　前記第３層および前記第４層は、可視光を反射しない粒子を含む繊維状構造体により形成されている、前記（１３）または（１４）に記載の表示装置。
（１６）
　前記可視光を反射しない粒子は、粒径が２５０ｎｍ以下のチタニア（ＴｉＯ2）である、前記（１５）に記載の表示装置。
（１７）
　前記繊維状構造体はアクリル樹脂からなる、前記（１）乃至（１６）のうちのいずれかに記載の表示装置。
（１８）
　前記泳動粒子および前記多孔質層を含む絶縁性液体を有し、前記絶縁性液体中に、さらに前記泳動粒子を分散させる分散剤を含有する、前記（１）乃至（１８）のうちのいずれかに記載の表示装置。
（１９）
　表示装置を備え、
　前記表示装置は、
　互いに平均粒径の異なる複数種類の泳動粒子と、
　繊維状構造体により形成されると共に、互いに平均孔径が異なる複数の多孔質層と
　を有する電子機器。 In addition, this indication can also take the following structures.
(1)
A plurality of types of migrating particles having different average particle sizes,
A display device comprising a plurality of porous layers formed of a fibrous structure and having different average pore diameters.
(2)
The display device according to (1), including a display surface, wherein the plurality of porous layers are laminated to each other, and an average pore diameter decreases from the display surface toward the back surface.
(3)
The display device according to (1) or (2), wherein the plurality of types of migrating particles have different colors.
(4)
The display device according to any one of (1) to (3), wherein the number of the plurality of porous layers is equal to or greater than the number of types of the migrating particles.
(5)
The plurality of porous layers have a first layer from the display surface side and a second layer having a smaller average pore diameter than the first layer,
The display device according to any one of (2) to (4), wherein the thickness of the first layer is larger than that of the second layer.
(6)
The display device according to any one of (1) to (5), wherein each of the plurality of types of migrating particles is charged and has a different charge amount.
(7)
The display device according to any one of (1) to (6), wherein each of the plurality of porous layers is charged and has a different charge amount.
(8)
The display device according to any one of (1) to (7), wherein an average particle diameter of the plurality of types of migrating particles is 100 nm to 2 μm.
(9)
The display device according to any one of (1) to (8), wherein an average pore diameter of the plurality of porous layers is 0.1 μm or more and 5 μm or less.
(10)
The porous layer has non-migrating particles held in the fibrous structure,
The non-electrophoretic particles have a light reflectance higher than that of the electrophoretic particles, the electrophoretic particles display dark, and the non-electrophoretic particles and the fibrous structure perform bright display. The display apparatus in any one of.
(11)
The electrophoretic particles and the non-electrophoretic particles are composed of at least one of an organic pigment, an inorganic pigment, a dye, a carbon material, a metal material, a metal oxide, glass, and a polymer material. ) Display device.
(12)
(1), (3), (4), (6) having a display surface, wherein the plurality of porous layers have a laminated structure in which an average pore diameter decreases from a back surface toward the display surface. The display device according to any one of (9) to (9).
(13)
The plurality of porous layers have a third layer from the display surface side and a fourth layer having a larger average pore diameter than the third layer,
The display device according to (12), wherein each of the third layer and the fourth layer has optical transparency.
(14)
The plurality of porous layers further have a fifth layer on the back side of the fourth layer,
The display device according to (13), wherein the fifth layer has an optical reflection characteristic different from that of the plurality of types of migrating particles.
(15)
The display device according to (13) or (14), wherein the third layer and the fourth layer are formed of a fibrous structure including particles that do not reflect visible light.
(16)
The display device according to (15), wherein the particles that do not reflect visible light are titania (TiO 2 ) having a particle size of 250 nm or less.
(17)
The display device according to any one of (1) to (16), wherein the fibrous structure is made of an acrylic resin.
(18)
Any of (1) to (18), including an insulating liquid including the electrophoretic particles and the porous layer, and further containing a dispersant for dispersing the electrophoretic particles in the insulating liquid. The display device described in 1.
(19)
A display device,
The display device
A plurality of types of migrating particles having different average particle sizes,
An electronic device having a plurality of porous layers formed of a fibrous structure and having different average pore diameters.
　本出願は、日本国特許庁において２０１５年６月８日に出願された日本特許出願番号２０１５－１１５６１３号を基礎として優先権を主張するものであり、この出願の全ての内容を参照によって本出願に援用する。 This application claims priority based on Japanese Patent Application No. 2015-115613 filed on June 8, 2015 at the Japan Patent Office. The entire contents of this application are hereby incorporated by reference. Incorporated into.
　当業者であれば、設計上の要件や他の要因に応じて、種々の修正、コンビネーション、サブコンビネーション、および変更を想到し得るが、それらは添付の請求の範囲やその均等物の範囲に含まれるものであることが理解される。 Those skilled in the art will envision various modifications, combinations, subcombinations, and changes, depending on design requirements and other factors, which are within the scope of the appended claims and their equivalents. It is understood that

Claims (19)

  1. 　互いに平均粒径の異なる複数種類の泳動粒子と、
    　繊維状構造体により形成されると共に、互いに平均孔径が異なる複数の多孔質層と
    　を備えた表示装置。     A plurality of types of migrating particles having different average particle sizes,
    A display device comprising a plurality of porous layers formed of a fibrous structure and having different average pore diameters.
  2. 　表示面を有し、前記複数の多孔質層は互いに積層されており、前記表示面から背面に向かって平均孔径が小さくなっていく、請求項１に記載の表示装置。 The display device according to claim 1, comprising a display surface, wherein the plurality of porous layers are laminated with each other, and an average pore diameter decreases from the display surface toward the back surface.
  3. 　前記複数種類の泳動粒子は、互いに異なる色を有する、請求項１に記載の表示装置。 The display device according to claim 1, wherein the plurality of types of migrating particles have different colors.
  4. 　前記複数の多孔質層の層数は、前記泳動粒子の種類と同数以上である、請求項１に記載の表示装置。 The display device according to claim 1, wherein the number of the plurality of porous layers is equal to or more than the number of the migrating particles.
  5. 　前記複数の多孔質層は、前記表示面側から第１層および前記第１層よりも平均孔径の小さな第２層を有し、
    　前記第１層の厚みは、前記第２層よりも大きい、請求項２に記載の表示装置。     The plurality of porous layers have a first layer from the display surface side and a second layer having a smaller average pore diameter than the first layer,
    The display device according to claim 2, wherein a thickness of the first layer is larger than that of the second layer.
  6. 　前記複数種類の泳動粒子はそれぞれ帯電すると共に、互いに帯電量が異なる、請求項１に記載の表示装置。 The display device according to claim 1, wherein the plurality of types of migrating particles are each charged and have different charge amounts.
  7. 　前記複数の多孔質層はそれぞれ帯電すると共に、互いに帯電量が異なる、請求項１に記載の表示装置。 The display device according to claim 1, wherein each of the plurality of porous layers is charged and has a different charge amount.
  8. 　前記複数種類の泳動粒子の平均粒径は、１００ｎｍ以上２μｍ以下である、請求項１に記載の表示装置。 The display device according to claim 1, wherein an average particle diameter of the plurality of types of migrating particles is 100 nm or more and 2 µm or less.
  9. 　前記複数の多孔質層の平均孔径は、０．１μｍ以上５μｍ以下である、請求項１に記載の表示装置。 The display device according to claim 1, wherein an average pore diameter of the plurality of porous layers is 0.1 μm or more and 5 μm or less.
  10. 　前記多孔質層は、前記繊維状構造体に保持された非泳動粒子を有し、
    　前記非泳動粒子の光反射率は前記泳動粒子の光反射率よりも高く、前記泳動粒子が暗表示、前記非泳動粒子および繊維状構造体が明表示を行う、請求項１に記載の表示装置。     The porous layer has non-migrating particles held in the fibrous structure,
    2. The display device according to claim 1, wherein the light reflectance of the non-electrophoretic particles is higher than the light reflectance of the electrophoretic particles, the electrophoretic particles perform dark display, and the non-electrophoretic particles and the fibrous structure perform bright display. .
  11. 　前記泳動粒子および前記非泳動粒子は、有機顔料，無機顔料，染料，炭素材料，金属材料，金属酸化物，ガラスおよび高分子材料のうちの少なくともいずれか１つにより構成されている、請求項１０に記載の表示装置。 The electrophoretic particles and the non-electrophoretic particles are composed of at least one of an organic pigment, an inorganic pigment, a dye, a carbon material, a metal material, a metal oxide, glass, and a polymer material. The display device described in 1.
  12. 　表示面を有し、前記複数の多孔質層は、背面から前記表示面に向かって平均孔径が小さくなっていく積層構造を有する、請求項１に記載の表示装置。 The display device according to claim 1, further comprising: a display surface, wherein the plurality of porous layers have a laminated structure in which an average pore diameter decreases from a back surface toward the display surface.
  13. 　前記複数の多孔質層は、前記表示面側から第３層および前記第３層よりも平均孔径の大きな第４層を有し、
    　前記第３層および前記第４層は、それぞれ光透過性を有する、請求項１２に記載の表示装置。     The plurality of porous layers have a third layer from the display surface side and a fourth layer having a larger average pore diameter than the third layer,
    The display device according to claim 12, wherein each of the third layer and the fourth layer has light transmittance.
  14. 　前記複数の多孔質層は、前記第４層の背面側にさらに第５層を有し、
    　前記第５層は、前記複数種類の泳動粒子とは異なる光学的反射特性を有する、請求項１３に記載の表示装置。     The plurality of porous layers further have a fifth layer on the back side of the fourth layer,
    The display device according to claim 13, wherein the fifth layer has an optical reflection characteristic different from that of the plurality of types of migrating particles.
  15. 　前記第３層および前記第４層は、可視光を反射しない粒子を含む繊維状構造体により形成されている、請求項１３に記載の表示装置。 14. The display device according to claim 13, wherein the third layer and the fourth layer are formed of a fibrous structure including particles that do not reflect visible light.
  16. 　前記可視光を反射しない粒子は、粒径が２５０ｎｍ以下のチタニア（ＴｉＯ2）である、請求項１５に記載の表示装置。 The display device according to claim 15, wherein the particles that do not reflect visible light are titania (TiO 2 ) having a particle size of 250 nm or less.
  17. 　前記繊維状構造体はアクリル樹脂からなる、請求項１に記載の表示装置。 The display device according to claim 1, wherein the fibrous structure is made of an acrylic resin.
  18. 　前記泳動粒子および前記多孔質層を含む絶縁性液体を有し、前記絶縁性液体中に、さらに前記泳動粒子を分散させる分散剤を含有する、請求項１に記載の表示装置。 The display device according to claim 1, further comprising an insulating liquid including the migrating particles and the porous layer, and further containing a dispersant that disperses the migrating particles in the insulating liquid.
  19. 　表示装置を備え、
    　前記表示装置は、
    　互いに平均粒径の異なる複数種類の泳動粒子と、
    　繊維状構造体により形成されると共に、互いに平均孔径が異なる複数の多孔質層と
    　を有する電子機器。     A display device,
    The display device
    A plurality of types of migrating particles having different average particle sizes,
    An electronic device having a plurality of porous layers formed of a fibrous structure and having different average pore diameters.
PCT/JP2016/065974 2015-06-08 2016-05-31 Display device and electronic apparatus WO2016199617A1 (en)

Applications Claiming Priority (2)

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JP2015-115613 2015-06-08

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008286855A (en) * 2007-05-15 2008-11-27 Fuji Xerox Co Ltd Display medium and display device
JP2012093627A (en) * 2010-10-28 2012-05-17 Seiko Epson Corp Display sheet, display device and electronic apparatus
WO2013077163A1 (en) * 2011-11-22 2013-05-30 ソニー株式会社 Electrophoretic element, method of manufacturing same, and display device
WO2014038291A1 (en) * 2012-09-05 2014-03-13 ソニー株式会社 Electrophoretic element, display device, and electronic apparatus

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008286855A (en) * 2007-05-15 2008-11-27 Fuji Xerox Co Ltd Display medium and display device
JP2012093627A (en) * 2010-10-28 2012-05-17 Seiko Epson Corp Display sheet, display device and electronic apparatus
WO2013077163A1 (en) * 2011-11-22 2013-05-30 ソニー株式会社 Electrophoretic element, method of manufacturing same, and display device
WO2014038291A1 (en) * 2012-09-05 2014-03-13 ソニー株式会社 Electrophoretic element, display device, and electronic apparatus

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