JP2011039381A - Display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display having improved brightness as compared to the case of using no display element. <P>SOLUTION: This color filter 10 (display) has such a structure that a plurality of display elements 16 are arrayed in the surface direction of substrates between substrates, that is between a substrate 12 and a substrate 14. Each of the display elements 16 includes an electrode 20 disposed on the substrate 12 side and an electrode 18 disposed on the substrate 14 side. On the surface side of one of the two electrodes, the surface side facing the other electrode, a porous layer 22 is disposed, an EC1 pigment 24 is retained on the porous layer 22, an EC2 pigment 28 is dispersed in an electrolyte 26 and, with respect to each of the EC1 pigment 24 and the EC2 pigment 28, the threshold of voltage to be applied between the electrode 20 and the electrode 18 for causing the change from a discolored state to a colored state satisfies the following inequality (1): E1<E2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a display device.

  In Patent Document 1, a piezoelectric transparent first layer and a piezoelectric transparent second layer having a refractive index different from that of the first layer are alternately stacked, and the main body is sandwiched. A color filter including a pair of transparent electrodes arranged in this manner has been proposed. In Patent Document 1, by applying a voltage to the pair of transparent electrodes, the first layer and the second layer are deformed to change the resonance wavelength, thereby forming a color variable color filter. .

  Patent Document 2 proposes a filter that alternately transmits light of various colors with a single voltage operation by using a plurality of nematic liquid crystal layers and using superposition of transmission wavelengths.

  In Patent Document 3, a resonator structure is formed, and the reflective film is displaced by electrostatic attraction, thereby changing the resonance wavelength to constitute a color variable color filter.

Japanese Patent Laid-Open No. 10-048675 JP 2000-267127 A JP 2008-116669 A

  An object of the present invention is to provide a display device that improves brightness when used as a color filter, compared to the case where the display element of the present invention is not used.

  The invention according to claim 1 includes a pair of substrates and a plurality of display elements provided between the pair of substrates and arranged in a surface direction of the substrates, and each of the plurality of display elements includes: A first electrode provided on one substrate side of the pair of substrates, a second electrode provided on the other substrate side of the pair of substrates, the first electrode, and the first electrode An electrolyte disposed between the two electrodes, a conductive or semiconductive porous layer disposed on one of the opposing surfaces of the first electrode and the second electrode, and the porous A first electrochromic dye held in the electrolyte layer, and a second electrochromic dye dispersed in the electrolyte and colored in a different color from the first electrochromic dye, Electrochromic dye and second electrochromic dye Both of them are an oxidized dye that develops color by an electrochemical oxidation reaction and disappears by a reduction reaction, or a reduced dye that develops color by an electrochemical reduction reaction and disappears by an oxidation reaction, the first electrochromic The threshold value of the voltage applied between the first electrode and the second electrode in order to change from the decolored state to the colored state of the dye and the second electrochromic dye is expressed by the following formula (1): It is a display device that satisfies the relationship.

              E1 <E2 Formula (1)

  In the formula (1), E1 is a threshold voltage applied between the first electrode and the second electrode in order for the first electrochromic dye to change from a decolored state to a colored state. E2 is a threshold value of a voltage applied between the first electrode and the second electrode in order for the second electrochromic dye to change from a decolored state to a colored state. Indicates the absolute value of.

  According to a second aspect of the present invention, at least one of the first electrochromic dye and the second electrochromic dye develops colors of a plurality of different colors in the color development state, and changes to each kind of color. The display device according to claim 1, wherein thresholds of voltages applied between the first electrode and the second electrode are different from each other.

  According to a third aspect of the present invention, the color of the first electrochromic dye and the second electrochromic dye in the colored state is any one of red, green, and blue. 2. The display device according to 2.

  According to the first aspect of the present invention, there is provided a display device that improves the brightness when used as a color filter compared to the case where the display element according to the present invention is not used.

  According to the second aspect of the present invention, multicolor display is realized as compared with the case where a dye that develops only one color is used as the electrochromic dye.

  According to the third aspect of the present invention, the application range of the display device when used as a color filter is widened as compared with a case where an electrochromic dye that colors red, green, and blue is not used.

FIG. 3 is a schematic diagram illustrating an example in which a part of the color filter of the present embodiment is enlarged, and is a cross-sectional view taken along line A-A ′ in FIG. It is a schematic diagram which shows an example of the color filter of this Embodiment. It is typical sectional drawing which expanded a part of the display substrate side of the display element in the color filter of this Embodiment. (A)-(D) It is typical sectional drawing which expanded a part by the side of the display substrate of the display element in the color filter of this Embodiment. (A)-(C) It is typical sectional drawing which expanded a part by the side of the display substrate of the display element in the color filter of this Embodiment. It is a schematic diagram which shows an example of the form different from FIG. 3 in the color filter of this Embodiment. (A), (C) is the enlarged schematic diagram of the area | region corresponding to the pixel in the conventional color filter, (B), (D) shows the area | region corresponding to the pixel in the color filter of this Embodiment. It is the enlarged schematic diagram. (A), (B) It is the schematic diagram which shows an example which expanded a part of color filter of this Embodiment, and is the figure which showed the form different from FIG. It is the schematic diagram which shows an example which expanded a part of color filter of this Embodiment, and is the figure which showed the form different from FIG. (A) is a schematic diagram illustrating an electrical configuration of the color filter of the present embodiment, and (B) is a schematic diagram in which a region corresponding to the pixel in FIG. 10 (A) is enlarged.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol may be provided to the member which an effect | action and function bear the same function through all the drawings, and the overlapping description may be abbreviate | omitted.

  In the present embodiment, as shown in FIG. 1, the color filter 10 includes a substrate 12 on the display surface side, a substrate 14 disposed so as to face the substrate 12 with a space therebetween, and these substrates 12. A plurality of display elements 16 provided between the substrate 14 and the substrate, a voltage applying unit 30, and a control unit 32 are included.

In the present embodiment, the color filter 10 is described as having a configuration including the voltage application unit 30 and the control unit 32, but the voltage application device 31 including the voltage application unit 30 and the control unit 32 is provided. Alternatively, the substrate 12, the substrate 14, and the component part 11 including the plurality of display elements 16 may be configured as separate bodies, and only the component part 11 may be used as the color filter 10.
In this case, the constituent part 11 is configured to be detachable from the voltage applying device 31, and the constituent part 11 and the voltage applying device 31 are attached to the voltage applying device 31. What is necessary is just to comprise so that it may electrically connect through the electrode (The electrode 20 and the electrode 18) mentioned later.
In the present embodiment, the color filter 10 will be described, but the color filter 10 also functions as a display device and is included in the concept of the display device.

  A plurality of display elements 16 are arranged in the area between the substrate 12 and the substrate 14 in the surface direction of the substrate (see FIGS. 1 and 2). Specifically, the region corresponding to each pixel of the color filter 10 is configured to include a plurality of display elements 16.

  In the present embodiment, as shown in FIG. 2, the plurality of display elements 16 arranged in the plane direction of the substrate 12 and the substrate 14 are classified into three display elements 16 arranged in succession, and this classification is performed. A case will be described in which a region including the three display elements 16 as a set is a region (region X in FIG. 2) corresponding to one pixel. Therefore, the description will be made assuming that the three display elements 16 included in the region X corresponding to each pixel in FIG. 2 are regions indicating colors corresponding to one pixel in the color filter 10.

  In the present embodiment, the number of display elements 16 included in a region corresponding to one pixel is described as three. However, the number of display elements 16 included in a region corresponding to one pixel is as follows. The number is not limited to three as long as it is plural (two or more). Further, the plurality of continuous display elements 16 included in the region corresponding to one pixel are not limited to the display elements 16 continuous in the same direction, but different directions (for example, the X-axis direction and the Y-axis direction). The display element 16 may be continuous in the crossing direction.

  As shown in FIGS. 1 and 3, the display element 16 is filled with an electrode 20 provided on the substrate 12 side, an electrode 18 provided on the substrate 14 side, and between these electrodes 20 and 18. And an electrolyte 26. In addition, any one of the electrode 20 provided on the substrate 12 side and the electrode 18 provided on the substrate 14 side has a conductive or semiconductive property on the side facing the other electrode. A porous layer 22 is provided.

In the present embodiment, “conductive” and “conductive” mean a volume resistivity of less than 10 ² Ω · cm. Further, “semiconductive” and “semiconductor” mean a volume resistivity of 10 ² Ωcm or more and 10 ⁵ Ωcm or less.

  As shown in FIG. 3, the porous layer 22 holds a first electromic dye (hereinafter also referred to as EC1 dye) 24 as an electrochromic dye (hereinafter also referred to as EC dye). Has been. In the electrolyte 26, a second electrochromic dye (hereinafter sometimes referred to as EC2 dye) 28 is dispersed as an electrochromic dye.

Although described in detail later, the electrochromic dye is a dye that develops or decolors by at least one of an electrochemical oxidation reaction and a reduction reaction.
In each of the display elements 16 provided in plurality in the color filter 10 of the present embodiment, at least two types of electrochromic dyes that develop colors different from each other are between the substrates 12 and 14 (that is, the electrodes 20 and the electrodes). The electrochromic dye of one (EC1 dye 24 in the present embodiment) is held in the porous layer 22 and the other (EC2 dye 28 in the present embodiment). ) Is dispersed in the electrolyte 26.

  Note that the EC1 dye 24 retained in the porous layer 22 and the EC2 dye 28 dispersed in the electrolyte 26 are both oxidized dyes or both reduced dyes. Therefore, when the EC1 dye 24 is an oxidized dye, the EC2 dye 28 is also an oxidized dye, and when the EC1 dye 24 is a reduced dye, the EC2 dye 28 is also a reduced dye. .

The oxidized dye is an EC dye that is decolored by an electrochemical reduction reaction to be in a decolored state and colored by an oxidation reaction to be in a colored state. The reduced dye is an EC dye that is decolored by an electrochemical oxidation reaction to be decolored and colored by a reduction reaction to be in a colored state.
The “colored state” indicates a colored state, which means a state having an absorption peak in at least a visible light region and visually recognized as a colored state. In addition, the “decolored state” indicates a decolored state, at least a state having an absorption peak in a region other than the visible light region, and a state visually recognized as a colorless or ultra-light color decolored state Means.

  Further, each of the EC1 dye 24 held in the porous layer 22 and the EC2 dye 28 dispersed in the electrolyte 26 has a gap between the electrode 20 and the electrode 18 in order to change from the decolored state to the colored state. The threshold value of the applied voltage satisfies the relationship of the following formula (1).

              E1 <E2 Formula (1)

  In formula (1), E1 is the absolute value of the threshold value of the voltage applied between the electrode 20 and the electrode 18 in order for the EC1 dye 24 held in the porous layer 22 to change from the decolored state to the colored state. E2 represents the absolute value of the threshold value of the voltage applied between the electrodes so that the EC2 dye 28 dispersed in the electrolyte 26 changes from the decolored state to the colored state.

  The relationship between the threshold values of the EC1 dye 24 and the EC2 dye 28 satisfies the relationship of the above formula (1), the EC1 dye 24 is held in the porous layer 22, and the EC2 dye 28 is dispersed in the electrolyte 26. Therefore, in each of the display elements 16 provided in a plurality in the color filter 10 of the present embodiment, one of the display elements 16 is in a colored state due to an oxidation-reduction reaction caused by exchange of electrons between molecules of the EC1 dye 24 and the EC2 dye 28. And the other is considered to be in a decolored state. For this reason, it is considered that both EC dyes are prevented from being colored at the same time, and color mixing in the colored state between the respective dyes is suppressed.

  Therefore, in each display element 16 provided in the color filter 10 of the present embodiment, a specific electrochromic dye contained in each display element 16 is selectively colored, and one display element 16 has Multiple different colors are displayed.

  In the color filter 10 of the present embodiment, a plurality of display elements 16 are arranged between the substrates 12 and 14 in the surface direction of the substrate. For this reason, a region corresponding to each pixel is determined so as to include a plurality of display elements 16 (for example, three display elements 16), and all of the plurality of display elements 16 included in the region corresponding to each pixel are arbitrarily set. A specific electrochromic dye is selectively developed by applying a voltage between the electrodes so that the color (for example, red) is displayed. As a result, the arbitrary color (for example, red) is displayed not in a part of the area corresponding to each pixel but in the entire area corresponding to the pixel, and the conventional color is fixed. Compared to the filter, it is considered that a color filter in which the brightness of the region corresponding to each pixel is improved is provided.

  That is, in the conventional color filter, an area for extracting only red light, an area for extracting only green light, and an area for extracting only blue light are defined as areas corresponding to one pixel. That is, the color filter is fixed in color. For this reason, each of red, green, and blue is displayed using only an area corresponding to 1/3 of an area corresponding to one pixel. Further, when displaying a secondary color, the display is performed using only an area corresponding to 2/3 of an area corresponding to one pixel.

  On the other hand, according to the color filter 10 of the present embodiment, a plurality of display elements 16 are arranged in the surface direction of the substrate. Therefore, a region including a plurality of display elements 16 arranged in succession, for example, three display elements 16 is defined as a region corresponding to each pixel, and the display elements 16 included in the region corresponding to each pixel If a voltage is applied between the electrodes so that the color (for example, red) when the electrochromic dye contained is in a specific color state is displayed on all, red is displayed in the entire area corresponding to each pixel. Will be. For this reason, it is considered that the color filter 10 in which the brightness of each pixel is improved as compared with the conventional color-fixed color filter is provided.

  In addition, when displaying secondary colors, it is considered that a color filter in which the brightness of each pixel is improved as compared with a conventional color-fixed color filter is provided (details will be described later).

  In addition, the color filter 10 according to the present embodiment corresponds to each pixel even when compared with the conventional configuration in which the color of the region corresponding to the pixel is made variable by stacking a plurality of layers that emit different colors. Since each of the plurality of display elements 16 constituting the region to selectively display the color by the contained electrochromic dye, compared to the conventional configuration in which the target color is displayed by overlapping the colors in the thickness direction, It is considered that a color filter 10 with improved brightness of each pixel is provided.

  Therefore, it is considered that the brightness of the color filter 10 of the present embodiment is improved as compared with the color filter of the conventional configuration that does not use the display element 16 of the present embodiment.

In addition, a specific effect | action and the detail of a specific electrochromic pigment | dye are mentioned later.
First, each member constituting the color filter 10 will be described.

-substrate-
As shown in FIG. 1, the substrate 12 and the substrate 14 are provided so as to sandwich a plurality of display elements 16 arranged in the plane direction. As described above, the substrate 12 is provided on the display surface side. Of these substrates 12 and 14, at least the substrate 12 is transparent. Note that in the present embodiment, translucency and transparency indicate that the average transmittance of visible light is 80% or more.

  As described above, a plurality of display elements 16 are arranged in the plane direction between the substrates 12 and 14. The substrate 12 and the substrate 14 are used as a base material for arranging a plurality of display elements 16 between the substrates in the surface direction of the substrate, and the material, shape, structure, size, etc. are particularly limited. There is no.

  As these board | substrate 12 and board | substrate 14, a glass plate, a polymer film, etc. are mentioned suitably, for example. Polymer film materials include tetraacetyl cellulose (TAC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), syndiotactic polystyrene (SPS), polyphenylene sulfide (PPS), polycarbonate (PC), polyarylate ( PAr), polysulfone (PSF), polyester sulfone (PES), polyetherimide (PEI), cyclic polyolefin, brominated phenoxy, and the like.

―Display element―
As described above, the display element 16 includes the electrode 20 provided on the substrate 12 side, the electrode 18 provided on the substrate 14 side, and the electrolyte 26 filled between these electrodes 20 and 18. It is supposed to be configured. In addition, any one of the electrode 20 provided on the substrate 12 side and the electrode 18 provided on the substrate 14 side has a conductive or semiconductive property on the side facing the other electrode. A porous layer 22 is provided. As shown in FIG. 2, the EC1 dye 24 is held in the porous layer 22, and the EC2 dye 28 is dispersed in the electrolyte 26.

-electrode-
The electrode 20 and the electrode 18 are disposed on each of the substrate 12 and the substrate 14 so as to selectively drive each of the plurality of display elements 16 provided in the color filter 10. For example, as shown in FIG. 10A, the electrodes 20 and 18 have a configuration in which a plurality of linear electrodes 18 are arranged on the substrate 14 side, and a plurality of linear electrodes 20 are arranged on the substrate 12 side. The electrode 18 and the electrode 20 are arranged so that the arrangement directions thereof intersect each other. Then, the region X may be determined so that a plurality of regions where these electrodes 20 and 18 intersect are included in the region X corresponding to each pixel. The voltage application unit 30 includes a voltage application unit 30A that applies a voltage to the plurality of electrodes 20 and a voltage application unit 30B that applies a voltage to the plurality of electrodes 18. What is necessary is just to connect electrically to the voltage application part 30A and to electrically connect the some electrode 18 to the voltage application part 30B. With this configuration, so-called passive matrix driving is realized, and each display element 16 is selectively driven.
In FIG. 10A, the region X corresponding to each pixel is defined as a region where one electrode 18 and three electrodes 20 intersect, as shown in FIG. 3 shows a configuration in which three display elements 16 are arranged in the region X corresponding to each pixel.

  FIG. 10 shows an example in which the region X corresponding to each pixel is defined as a region where one electrode 18 and three electrodes 20 intersect. However, the present invention is not limited to this embodiment. A region where the plurality of electrodes 18 and the plurality of electrodes 20 intersect may be determined for the region X corresponding to the pixel, and may be selected according to the design of the color filter 10.

  FIG. 10 shows a passive matrix driving mode, but an active matrix driving mode may be used (details will be described later).

  The electrodes 20 and 18 are not particularly limited as long as they are transparent and can conduct electricity, and are appropriately selected according to the purpose. For example, indium tin oxide (ITO), tin oxide (NESA), fluorine-doped oxide Examples include tin (FTO), indium oxide, zinc oxide, platinum, gold, silver, rhodium, copper, chromium, and carbon. Among these, metal oxides typified by tin oxide-indium oxide (ITO), tin oxide, zinc oxide and the like are good, furthermore, the surface resistance value is low, the heat resistance is good, and there is chemical stability. In view of high light transmittance, tin oxide (FTO) doped with fluorine and indium tin oxide (ITO) are preferable.

  In particular, in the display element 16 of the color filter 10 according to the present embodiment, the conductive or semiconductive porous layer 22 is disposed in contact with the electrode 20, so that even if it is in contact with the porous layer 22, the chemical is used. In addition, tin oxide (FTO) and indium tin oxide (ITO), which are oxides, are preferable because they need to be stable.

  The thicknesses of the electrode 20 and the electrode 18 are not particularly limited and are selected according to the purpose. For example, the thickness is 0.1 μm or more, specifically 0.1 μm or more and 20 μm or less.

  These electrodes 20 and 18 are formed by a sputtering method, a sol-gel method, or a printing method. Further, in the color filter 10, as the electrode farthest away from the display surface side (Y direction in FIG. 1) (in this embodiment, the electrode 18), tin oxide-indium oxide (ITO), tin oxide, In addition to a metal oxide layer typified by zinc oxide or the like, a conductive polymer or a metal layer typified by carbon, copper, aluminum, gold, silver, nickel, platinum or the like may be used. However, when a carbon electrode or a metal electrode is used as the electrode, the film thickness of the electrode is preferably suppressed to about 200 nm or less in order to ensure transparency.

-Porous layer-
The porous layer 22 is laminated in contact with the electrode 20 and has conductivity or semiconductivity. In the present embodiment, the case where the porous layer 22 is provided by being laminated in contact with the electrode 20 provided on the display surface side of the electrode 20 and the electrode 18 will be described. The structure provided in contact with the 18th side may be sufficient.

  The porous layer 22 has a porous structure so as to have more micropores that hold the EC1 dye 24 on the surface and inside thereof. The porous layer 22 may have a single layer structure or a multilayer structure.

The specific surface area of the porous layer 22 is, for example, 1 m ² / g or more and 5000 m ² / g or less, or 10 m ² / g or more and 2500 m ² / g or less. Here, the specific surface area means the BET specific surface area obtained from the adsorption amount of nitrogen gas. When the specific surface area is within the above range, it is considered that the EC1 dye 24 having a retention amount sufficient for displaying a specific color in each display element 16 is retained.
The thickness of the porous layer 22 (total thickness in the case of a multilayer structure) is 1 μm or more and 200 μm or less, or 5 μm or more and 50 μm or less. When the thickness of the porous layer 22 is in the above range, the EC1 dye 24 having a retention amount that displays a specific color in each display element 16 is retained in the porous layer 22, and the target transparency or It is considered that a driving voltage is realized.

  The porous layer 22 may have any configuration, but it is preferable from the viewpoint of ease of manufacturing to form a porous state by filling conductive or semiconductive particles. The conductive or semiconductive particles contained in the porous layer 22 are not particularly limited and are selected according to the purpose. For example, a single semiconductor, an oxide semiconductor, a compound semiconductor, an organic semiconductor, a composite oxide semiconductor Or a mixture thereof, which may contain impurities as a dopant. There is no particular limitation on the form of the semiconductor, and it may be single crystal, polycrystal, amorphous, or a mixed form thereof.

  Examples of the single semiconductor include silicon (Si), germanium (Ge), and tellurium (Te).

The oxide semiconductor is a metal oxide and has semiconductor properties. For example, TiO ₂ , SnO ₂ , Fe ₂ O ₃ , SrTiO ₃ , WO ₃ , ZnO, ZrO ₂ , Ta ₂ O ₅ , Nb ₂ Examples thereof include O ₅ , V ₂ O ₅ , In ₂ O ₃ , CdO, MnO, CoO, TiSrO ₃ , KTiO ₃ , Cu ₂ O, sodium titanate, barium titanate, and potassium niobate.

  Examples of the compound semiconductor include cadmium sulfide, zinc sulfide, lead sulfide, silver sulfide, antimony sulfide, bismuth sulfide, cadmium selenide, lead selenide, cadmium Examples include telluride, zinc phosphide, gallium phosphide, indium phosphide, cadmium phosphide, gallium-arsenic selenide, copper-indium selenide, copper-indium sulfide, and the like.

  Examples of the organic semiconductor include polythiophene, polypyrrole, polyacetylene, polyphenylene vinylene, polyphenylene sulfide, and the like.

Examples of the complex oxide semiconductor include SnO ₂ —ZnO, Nb ₂ O ₅ —SrTiO ₃ , Nb ₂ O ₅ —Ta ₂ O ₅ , Nb ₂ O ₅ —ZrO ₂ , Nb ₂ O ₅ —TiO ₂ , _{Ti-SnO 2, Zr-SnO} 2, Bi-SnO 2, In-SnO 2, Al-ZnO, such as Ga-ZnO and the like. The SnO ₂ —ZnO is composed of SnO ₂ super-particles (particle diameter, for example) around relatively large ZnO particles (for example, ZnO particles having a particle diameter of about 50 nm or less from the viewpoint of suppressing light scattering and ensuring transparency). The composite of the two is preferably in a range of SnO ₂ : ZnO = 70: 30 to 30:70 by mass ratio. The _{Nb 2 O 5 -SrTiO 3, Nb} 2 O 5 -Ta 2 O 5, Nb 2 O 5 -ZrO 2, and Nb ₂ O ₅ complex, such as Nb ₂ O ₅ -TiO ₂ includes a Nb ₂ O ₅ The mass ratio is 8: 2 or more and 2: 8 or less.

  The shape of the conductive or semiconductive particles is not particularly limited and is selected according to the purpose, and may be spherical, nanotube-shaped, rod-shaped, or whisker-shaped. You may mix the above particle | grains. In the case of the spherical particles, the number average particle diameter is 0.1 nm or more and 1000 nm or less, and 1 nm or more and 100 nm or less. Two or more kinds of particles having different particle size distributions may be mixed. Further, when the shape is the above-described rod shape, the aspect ratio is 2 or more and 50000 or less, or 5 or more and 25000 or less.

There is no restriction | limiting in particular as a method of forming the porous layer 22, It selects according to the kind of the structural material. For example, metal anodic oxidation method, cathodic deposition method, screen printing method, squeegee method, sol-gel method, thermal oxidation method, vacuum evaporation method, DC and DF sputtering method, chemical vapor deposition method, metal organic chemical vapor deposition method, molecule Examples thereof include a line deposition method and a laser ablation method, and the above methods may be combined.
As a specific forming method, a porous layer forming method disclosed in JP-A-2003-255400 may be used.

-Electrolytes-
As the electrolyte 26, it is sufficient that the EC2 dye 28 is dispersed, and the dispersed EC2 dye 28 can move between the substrate 12 and the substrate 14, and may be liquid or gel. Note that the electrolyte 26 may be a solid as long as the EC2 dye 28 dispersed therein moves the electrolyte 26.

  When the electrolyte 26 is a liquid, the electrolyte 26 is preferably used by dissolving a constituent material of the electrolyte in a solvent.

Examples of the constituent material of the electrolyte include perchlorates such as lithium perchlorate, sodium perchlorate, calcium perchlorate, and tetrabutylammonium chlorate, iodine, bromine, LiI, NaI, KI, CsI, Metal halides such as CaI ₂ , LiBr, NaBr, KBr, CsBr, CaBr ₂ , tetraethylammonium iodide, tetrapropylammonium iodide, tetrabutylammonium iodide, tetramethylammonium bromide, tetraethylammonium bromide, tetrabromide bromide Halogenated salts of ammonium compounds such as butylammonium, alkyl viologens such as methyl viologen chloride, hexyl viologen bromide, polyhydroxybenzenes such as hydroquinone and naphthohydroquinone, ferrocene, ferrocyanate, etc. At least one such complex can be used, but not limited thereto. Further, when a plurality of electrolytes that generate redox pairs (redox couples) in advance, such as a combination of iodine and lithium iodide, are used, the performance of the display element 16, particularly the current characteristics, is improved. Among these, a combination of iodine and an ammonium compound or iodine and a metal iodide is preferable.

  Solvents for dissolving these electrolyte constituent materials include carbonate compounds such as ethylene carbonate and propylene carbonate, ethers such as dioxane, diethyl ether and ethylene glycol dialkyl ether, methanol, ethanol, isopropyl alcohol, ethylene glycol, propylene glycol, Alcohols such as polyethylene glycol, nitriles such as acetonitrile and benzonitrile, aprotic polar solvents such as dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, propylene carbonate, and ethylene carbonate, water, and the like are used. Is not to be done.

  Examples of the electrolyte concentration of the constituent material of the electrolyte in the solvent include 0.001 mol / l to 2 mol / l, or 0.01 mol / l to 1 mol / l.

  When the electrolyte 26 is in the form of a gel, polymer addition, oil gelling agent addition, and polyfunctional monomers are mixed and used in the electrolyte constituent material and the solvent. In the case of gelation by addition of the polymer, compounds described in “Polymer Electrolyte Revues-1 and 2” (JR MacCallum and CA Vincent co-edited, ELSEVIER APPLIED SCIENCE) are used. In particular, polyacrylonitrile, polyvinylidene fluoride, and the like are preferable. In the case of gelation by addition of the oil gelling agent, “J. Chem Soc. Japan, Ind. Chem. Sec., 46, 779 (1943)”, “J. Am. Chem. Soc., 111, 5542 (1989). ) "," J. Chem. Soc., Chem. Commun., 1993, 390 "," Angew. Chem. Int. Ed. Engl., 35, 1949 (1996) "," Chem. Lett., 1996, 885 ". "," J. Chem. Soc., Chem. Commun., 1997, 545 "and the like are used. In particular, compounds having an amide structure in the molecular structure are preferable.

  Further, as the electrolyte 26, a solid electrolyte layer formed by polymerizing a mixed liquid of a matrix material and a supporting electrolyte may be used.

  There is no restriction | limiting in particular as this electrolyte, It selects according to the objective, An inorganic electrolyte may be sufficient and an organic electrolyte may be sufficient. These may be used individually by 1 type, may use 2 or more types together, may be a commercial item, and may synthesize | combine suitably.

Examples of the inorganic electrolyte include inorganic acid anions-alkali metal salts, alkali metal salts, alkaline earth metals, etc. Among these, inorganic acid anions-alkali metal salts are preferable, and inorganic acid lithium salts are preferable. .
Examples of the inorganic acid anion-alkali metal salt include XAsF ₆ , XPF ₆ , XBF ₄ , XClO ₄ , etc. (wherein X represents H, Li, K or Na). Specific examples include lithium perchlorate.

Examples of the alkali metal salt include LiI, KI, LiCF ₃ SO ₃ , LiPF ₆ , LiClO ₄ , LiBF ₄ , LiSCN, LiAsF ₆ , NaCF ₃ SO ₃ , NaPF ₆ , NaClO ₄ , NaI, NaBF ₄ , NaAsF _6. , KCF ₆ SO ₃ , KPF ₆ , and the like. Examples of the organic electrolyte include organic acid anion-alkali metal salts, quaternary ammonium salts, anionic surfactants, imidazolium salts, etc. Among them, organic acid anions-alkali metal salts are good. Organic acid lithium salt is better.

  The amount of the matrix material used in the electrolyte layer is such that the molar ratio with the supporting electrolyte (matrix material: supporting electrolyte) is 70:30 or more and 5:95 or less, 50:50 or more, 10:90, or 50:50. 20:80 or less. The molar ratio means the ratio between the molar amount of the matrix material and the molar amount of ions of the supporting electrolyte. The molar amount of the matrix material means a molar amount in which the monomer unit of the polymer compound is converted into one molecule.

  Such a film-like solid electrolyte 26 is obtained by thinly extending a mixture solution of the matrix material and the supporting electrolyte with a small amount of a polymerization initiator such as benzoyl peroxide or azobisisobutyronitrile, followed by heating. It is prepared by polymerizing by adding a photopolymerization initiator such as Irgacure and polymerizing by ultraviolet irradiation. The thickness of the film is 30 μm or more and 500 μm or less, or 50 μm or more and 200 μm or less.

―Electrochromic dye―
Next, the electrochromic dye will be described.

  As described above, the electrochromic dye (EC dye) includes at least two kinds of electrochromic dyes between the electrodes 20 and 18 for each of the plurality of display elements 16 provided in the color filter 10. The electrochromic dye of one (EC1 dye 24 in the present embodiment) is held in the porous layer 22 and the other electrochromic dye (EC2 dye 28 in the present embodiment) is contained in the electrolyte 26. Are distributed. Further, each of the EC1 dye 24 held in the porous layer 22 and the EC2 dye 28 dispersed in the electrolyte 26 has a gap between the electrode 20 and the electrode 18 in order to change from the decolored state to the colored state. The threshold value of the applied voltage satisfies the relationship of the above formula (1).

  The EC dye used for each display element 16 of the color filter 10 of the present embodiment is not particularly limited as long as it exhibits an action of color development or decoloration by at least one of an electrochemical oxidation reaction and a reduction reaction. (In the case of EC1 dye 24 and EC2 dye 28, they are selected according to the purpose within a range satisfying the above formula (1), both of which are oxidized dyes or reduced dyes and are colored in different colors), for example, Suitable examples include organic compounds and metal complexes. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the metal complex include Prussian blue, metal-bipyridyl complex, metal phenanthroline complex, metal-phthalocyanine complex, metaferricyanide, and derivatives thereof. Examples of the organic material include (1) pyridine compounds, (2) conductive polymers, (3) styryl compounds, (4) donor / acceptor type compounds, (5) other organic dyes, and the like. Is mentioned.

  Examples of the (1) pyridine compounds include viologen, heptyl viologen (diheptyl viologen dibromide, etc.), methylenebispyridinium, phenanthroline, azobipyridinium, 2,2-bipyridinium complex, quinoline / isoquinoline, and the like.

  Examples of the conductive polymer (2) include polypyrrole, polythiophene, polyaniline, polyphenylenediamine, polyaminophenol, polyvinylcarbazole, polymer viologen polyion complex, TTF, and derivatives thereof.

  Examples of the (3) styryl compounds include 2- [2- [4- (dimethylamino) phenyl] ethenyl] -3,3-dimethylindolino [2,1-b] oxazolidine, 2- [4- [4- (Dimethylamino) phenyl] -1,3-butadienyl] -3,3-dimethylindolino [2,1-b] oxazolidine, 2- [2- [4- (dimethylamino) phenyl] ethenyl]- 3,3-dimethyl-5-methylsulfonylindolino [2,1-b] oxazolidine, 2- [4- [4- (dimethylamino) phenyl] -1,3-butadienyl] -3,3-dimethyl-5 -Sulfonylindolino [2,1-b] oxazolidine, 3,3-dimethyl-2- [2- (9-ethyl-3-carbazolyl) ethenyl] indolino [2,1-b] oxazolidine 2- [2- [4- (acetylamino) phenyl] ethenyl] -3,3-dimethyl-indolino [2,1-b] oxazolidine, and the like.

Examples of the (4) donor / acceptor type compounds include tetracyanoquinodimethane and tetrathiafulvalene.
Examples of (5) other organic dyes include, for example, phthalic acid, carbazole, methoxybiphenyl, anthraquinone, quinone, diphenylamine, aminophenol, Tris-aminophenylamine, phenylacetylene, cyclopentyl compound, benzodithiolium compound, squalium salt, Examples include cyanine, rare earth phthalocyanine complex, ruthenium diphthalocyanine, merocyanine, phenanthroline complex, pyrazoline, redox indicator, pH indicator, and derivatives thereof.
Moreover, fluorescein and this derivative (carboxy fluorescein) are mentioned.
Of these, viologen dyes and phthalic acid dyes are preferable.

In the color filter 10 of the present embodiment, as the EC dye, a reduction coloring type that is colorless or extremely light-colored in an oxidized state and develops a colored state in a reduced state and colorless in a reduced state. Alternatively, an oxidative coloring type that becomes an extremely light-colored decolored state and develops a colored state in an oxidized state and is selected according to the purpose.
Further, a multicolor coloring type in which several colors appear depending on the degree of reduction or oxidation in the coloring state may be used, and may be selected according to the purpose.

  As described above, the threshold value of the voltage applied between the electrode 20 and the electrode 18 in order to change from the decolored state to the colored state among the two types of EC dyes contained in each display element 16. The EC1 dye 24 having the smaller absolute value is held in the porous layer 22. This “holding” indicates a state in which the EC dye is held on the surface of the porous layer 22 and in each hole. As a method for retaining the EC dye in the porous layer 22, conventionally known methods such as a method of adsorbing the EC1 dye 24 on the surface of the porous layer 22, a method of chemically bonding the porous layer 22 and the EC1 dye 24, etc. Technology is applied.

  For example, a dry process such as a vacuum deposition method, a coating method such as spin coating, an electric field deposition method, an electric field polymerization method, or a natural adsorption method in which a solution of a compound to be held is immersed is selected. Above all, the natural adsorption method is capable of retaining functional molecules evenly throughout the fine pores of the metal oxide layer, and does not require any special equipment, and in many cases it is about a monomolecular layer. It has many advantages, such as no extra amount needed.

  As the natural adsorption method, a method in which a substrate having a well-dried porous layer 22 is dipped in a solution of EC dye to be held or a solution of EC dye to be held is applied to the porous layer 22 is used. It is done. In the former case, an immersion method, a dip method, a roller method, an air knife method, or the like is used. In the case of the dipping method, the dye may be adsorbed at room temperature, or may be carried out by heating and refluxing as described in JP-A-7-249790. Examples of the latter application method include a wire bar method, a slide hopper method, an extrusion method, a curtain method, a spin method, and a spray method.

  Examples of the solvent for dissolving the EC dye used in the EC dye solution include water, alcohols (methanol, ethanol, t-butanol, benzyl alcohol, etc.), nitriles (acetonitrile, propionitrile, 3- Methoxypropionitrile, etc.), nitromethane, halogenated hydrocarbons (dichloromethane, dichloroethane, chloroform, chlorobenzene, etc.), ethers (diethyl ether, tetrahydrofuran, etc.), dimethyl sulfoxide, amides (N, N-dimethylformamide, N, N -Dimethylacetamide), N-methylpyrrolidone, 1,3-dimethylimidazolidinone, 3-methyloxazolidinone, esters (ethyl acetate, butyl acetate, etc.), carbonates (diethyl carbonate, ethylene carbonate, propylene carbonate) ), Ketones (acetone, 2-butanone, cyclohexanone), hydrocarbons (hexane, petroleum ether, benzene, toluene, etc.) or mixed solvents thereof.

  In addition, as a method of chemically bonding the EC dye (EC1 dye 24) to the surface of the porous layer 22, a functional group may be interposed between the surface of the porous layer 22 and the EC dye skeleton. As this functional group, for example, a functional group such as an alkyl group, a phenyl group, an ester, and an amide is preferable. Further, the EC dye may be chemically bonded after the surface of the porous layer 22 is modified with a silane coupling agent or the like.

Examples of the adsorption amount of the EC dye (EC1 dye 24) to the porous layer 22 include 0.01 mmol or more and 100 mmol or less per unit surface area (1 m ² ) of the porous layer 22. Further, the adsorption amount of the EC1 dye 24 to each semiconductor particle constituting the porous layer 22 includes a range of 0.01 mmol to 100 mmol per 1 g of the semiconductor particles.
Although details will be described later, when a plurality of types of EC dyes that develop colors different from each other are further adsorbed on the porous layer 22, the total amount of EC dyes adsorbed on the porous layer 22 is within the above range. It is good to be.

  The porous layer 22 is preferably heat-treated (for example, at 100 ° C. or more and 550 ° C. or less for 10 minutes) before the EC dye (EC1 dye 24) is held. Thereby, it is considered that moisture and other impurities adsorbed on the surface of the porous layer 22 are removed, and it is considered that the surface of the porous layer 22 is activated and the EC dye is efficiently adsorbed.

On the other hand, of the two types of EC dyes contained in the display element 16, the one with the larger absolute value of the threshold value of the voltage applied between the electrode 20 and the electrode 18 in order to change from the decolored state to the colored state The EC2 dye 28 is dispersed in the electrolyte 26. The concentration of the EC dye (EC2 dye 28) dispersed in the electrolyte 26 in the electrolyte may be 0.001 mol / l or more and 2 mol / l or less, or 0.01 mol / l or more and 1 mol / l or less.
When a plurality of types of EC dyes that develop colors different from each other are dispersed in the electrolyte 26, the total concentration of EC dyes dispersed in the electrolyte 26 may be within the above range.

-Redox agent-
In the electrolyte 26, it is preferable that a redox agent that does not develop color (ie, does not develop color) due to a redox reaction is dispersed.

  By using the redox agent, it is considered that the redox reaction of the EC dye in the display element 16 proceeds efficiently, and the reversible coloring efficiency and decoloring efficiency of the EC dye are improved.

  Furthermore, the redox agent is preferably immobilized on the electrode on the counter electrode side of the electrode 20 and the electrode 18 where the porous layer 22 holding the EC1 dye 24 is provided. . As shown in FIG. 1, in the present embodiment, the porous layer 22 holding the EC1 dye 24 is provided on the electrode 20 side of the electrode 20 and the electrode 18. It is preferable that the redox agent is immobilized. As a result, it is considered that an oxidation-reduction reaction occurs efficiently on both electrode sides of the electrode 20 and the electrode 18, and the coloring efficiency and decoloring efficiency of the entire display element 16 are improved.

  As such a redox agent, any redox agent that does not develop color by a redox reaction may be used, and specific examples include ferrocene, phenothiazine, a combination of iodine and metal iodide, and the like. However, when applying a combination of iodine and metal iodide as the redox agent, it is preferable to consider the intensity of coloring. Among them, ferrocene is preferable from the viewpoint of high stability and a small absorption coefficient of the solution.

  In addition, as a method for immobilizing the redox agent on the surface of the electrode 18, the same method as the method for holding the EC1 dye 24 in the porous layer 22 described above may be used to hold the redox agent on the electrode 18. Good.

  The redox agent added to the electrolyte 26 is contained in a state of being dissolved or dispersed in the electrolyte 26, and the concentration in the electrolyte 26 is 0.001 mol / l or more and 2 mol / l or less, or 0. 01 mol / l or more and 1 mol / l or less is mentioned.

-Charge storage member-
Further, in order to efficiently generate an oxidation-reduction reaction of the EC dyes (EC1 dye 24 and EC2 dye 28) contained in each display element 16, it is preferable to provide a charge storage member 34 as shown in FIG. The charge storage member 34 is fixed on the electrode on the counter electrode side of the electrode 20 and the electrode 18 of each display element 16 and the side where the porous layer 22 holding the EC1 dye 24 is provided. Good to be. In the present embodiment, the charge storage member 34 is immobilized on the electrode 18 because the porous layer 22 holding the EC1 dye 24 is provided on the electrode 20 side of the electrode 20 and the electrode 18. It has been good.

  As the charge storage member 34, a member having a specific surface area of 1000 or more is selected. Examples of such a member having a large specific surface area include carbon and alumina, and specifically, activated carbon and carbon nanotubes. Since these members have a large specific surface area, the accumulated charge capacity is large and the surface has polarity. Therefore, by providing the charge storage member 34 on the electrode 18 on the opposite side of the electrode 20 and the electrode 18 on which the porous layer 22 holding the EC1 dye 24 is stacked, It is considered that an oxidation-reduction reaction occurs efficiently on the two electrodes 20 and 18 and the color development efficiency and the color erasing efficiency of each display element 16 are improved.

  In the color filter 10 of the present embodiment, the voltage application unit 30 is controlled by the control of the control unit 32, and a voltage is applied to each of the plurality of display elements 16 in the region corresponding to each pixel. The target color is displayed on the element 16. By displaying each color on each display element 16, the color filter 10 functions as a color filter with a variable color.

The control unit 32 includes various programs such as a CPU (central processing unit) that controls the operation of the entire color filter 10, a RAM (Random Access Memory) that temporarily stores various data, and a control program that controls the entire device. It is configured as a microcomputer including a stored ROM (Read Only Memory).
The voltage application unit 30 is a voltage application device for applying a voltage to the electrode 20 and the electrode 18, and applies a voltage according to the control of the control unit 32 between the electrode 20 and the electrode 18.

  Hereinafter, the operation of the color filter 10 in each display element 16 will be described.

  Here, as described above, in each display element 16, the EC1 dye 24 is held in the porous layer 22, and the EC2 dye 28 is dispersed in the electrolyte 26. For each of these EC dyes, the threshold value of the voltage applied between the electrode 20 and the electrode 18 in order to change from the decolored state to the colored state is expressed by the above equation (1) as E1 <E2. Satisfies.

  As described above, in formula (1), E1 is the voltage applied between the pair of electrodes in order for the EC1 dye 24 held in the porous layer 22 to change from the decolored state to the colored state. E2 indicates the absolute value of the threshold value, and E2 indicates the absolute value of the threshold value of the voltage applied between the pair of electrodes in order for the EC2 dye 28 dispersed in the electrolyte 26 to change from the decolored state to the colored state. Yes.

  Further, as described above, the EC1 dye 24 and the EC2 dye 28 are both reduced dyes or both oxidized dyes.

For example, it is assumed that both the EC1 dye 24 and the EC2 dye 28 are reduction-type dyes (a color is developed by a reduction reaction and a color is erased by an oxidation reaction). Then, a voltage is applied between the electrodes 20 and 18 so that the electrode 20 side becomes a negative electrode and the electrode 18 side becomes a positive electrode, and the applied voltage is gradually increased to obtain a voltage value E1 that is a threshold value of the EC1 dye 24. Is applied, the EC1 dye 24 having a smaller threshold value held in the porous layer 22 provided in contact with the electrode 20 out of the EC1 dye 24 and the EC2 dye 28 is more than the EC2 dye 28. It is reduced first and changes from the non-colored state to the colored state (see FIGS. 4A and 4B).
That is, as shown in FIG. 4B, when a voltage having the voltage value E1 is applied between the electrode 20 and the electrode 18 with the electrode 20 side as the negative electrode, the EC1 dye 24 dye is reduced to form a colored state. However, the EC2 dye 28 has not yet been reduced and is in a non-colored state. Therefore, at this time, it is considered that only the color of the EC1 dye 24 is selectively displayed on the display element 16.

  In the course of further increasing the voltage applied between the electrodes 20 and 18, the EC2 dye 28 dispersed in the electrolyte 26 is reduced to the EC1 dye 24 that has been reduced to generate radicals. Is considered to be attracted (see FIG. 4C).

  When the voltage applied between the electrode 20 and the electrode 18 is further increased and the voltage of the voltage value E2 that is the threshold value of the EC2 dye 28 is applied, the EC2 dye 28 is reduced to develop color from the non-colored state. Change to state. At this time, since the EC2 dye 28 has a higher threshold value between the EC1 dye 24 and the EC2 dye 28, it is considered that electrons move between molecules from the EC1 dye 24 to the EC2 dye 28 (FIG. 4 ( D)). By the exchange of electrons between the EC1 dye 24 and the EC2 dye 28, the EC1 dye 24 held in the porous layer 22 is oxidized and decolored, and the EC2 dye 28 is reduced and decolored. It is thought to change to a colored state. For this reason, it is considered that the EC1 dye 24 and the EC2 dye 28 are prevented from being in a colored state at the same time, only the EC1 dye 24 is in a decolored state, and only the EC2 dye 28 is in a colored state.

On the other hand, when the voltage applied between the electrodes is gradually increased with the electrode 20 side as the positive electrode and the electrode 18 side as the negative electrode, the reverse phenomenon occurs.
Specifically, when the voltage applied between the electrodes is gradually increased with the electrode 20 side as the positive electrode and the electrode 18 side as the negative electrode, the EC2 dye 28 of the EC1 dye 24 and the EC2 dye 28 is the first. Oxidized to lose electrons and change from a colored state to a decolored state. The electrons lost from the EC2 dye 28 due to the transfer of electrons between the EC1 dye 24 and the EC2 dye 28 are received by the EC1 dye 24, and the EC1 dye 24 is reduced to develop the color from the decolored state. It is thought to change to a state.

  Further, when the electrode 20 side is the positive electrode and the electrode 18 side is the negative electrode, and the voltage applied between the electrodes is further increased gradually, the electrons received by the EC1 dye 24 move to the electrode 20, and the EC1 dye 24 is also considered to change from the colored state to the decolored state. For this reason, it is considered that the EC1 dye 24 and the EC2 dye 28 are simultaneously brought into a colored state, and only one of the EC1 dye 24 and the EC2 dye 28 is selectively brought into a colored state. .

  Thus, each display element 16 of the color filter 10 holds the EC1 dye 24 in the porous layer 22 disposed in contact with the electrode 18 side of the electrode 20 and the electrode 18, and the EC2 dye 28 in the electrolyte 26. Are distributed. In each display element 16, as the EC1 dye 24 and the EC2 dye 28, the colors in the colored state are different from each other, satisfy the relationship of the above formula (1), and both are oxidized dyes or reduced dyes. In this way, each display element 16 is configured, and a voltage is applied between the electrodes 20 and 18 to change the applied voltage and polarity, thereby changing the EC1 according to the polarity and voltage value of the applied voltage. It is considered that only a specific EC dye among the dye 24 and the EC2 dye 28 is selectively colored.

  As described above, it is considered that the plurality of display elements 16 included in the color filter 10 of the present embodiment suppresses color mixing between EC dyes and selectively displays a target color according to an applied voltage. .

  In the above description, a case has been described in which an EC dye that emits a single color is used as the EC dye contained in each display element 16, but the voltage applied between the electrodes 20 and 18 in the colored state is described. Depending on the value, EC dyes that develop a plurality of different colors may be used. In this way, by adjusting the polarity and voltage value of the voltage applied between the electrodes 20 and 18, further multicolor display is possible.

  For example, it is assumed that the EC1 dye 24 is different from the color in the color development state of the EC2 dye 28 and satisfies the relationship of the above formula (1) and develops two different colors. Further, it is assumed that the threshold voltages of the voltages applied between the electrodes 20 and 18 are different from each other in order to change to the two kinds of colors in the color development state of the EC1 dye 24. It is assumed that thresholds of voltages applied between the electrodes for changing to these two kinds of colors (for example, the first color and the second color) are E1 (A) and E1 (B), and E1 ( Suppose that the relationship of A) <E2 (B) <E2 is satisfied.

Further, assuming that both the EC1 dye 24 and the EC2 dye 28 are reduced dyes, in this case, for example, the electrode 20 side is a negative electrode and the electrode 18 side is a positive electrode. When a voltage is applied and the applied voltage is gradually increased and a voltage value E1 (A) that is a threshold value of the EC1 dye 24 is applied, the electrode 20 of the EC1 dye 24 and the EC2 dye 28 contacts the electrode 20. The EC1 dye 24 having a smaller threshold value held in the porous layer 22 provided in a reduced state is reduced before the EC2 dye 28 (see FIG. 4B), and changes from the non-colored state to the colored state. Thus, it is considered that a color development state in which the first color corresponding to the threshold value E1 (A) is developed.
Therefore, at this time, it is considered that only the first color of the EC1 dye 24 is selectively displayed on the display element 16.

Further, when the voltage of the voltage value E2 (A), which is a threshold value for developing the second color of the EC1 dye 24 by gradually increasing the applied voltage, the reduction reaction of the EC1 dye 24 proceeds. (See FIG. 5A), it is considered that a color development state in which the second color corresponding to the threshold value E1 (B) is developed.
Therefore, at this time, it is considered that only the second color of the EC1 dye 24 is selectively displayed on the display element 16.

  In the course of further increasing the voltage applied between the electrodes 20 and 18, the EC2 dye 28 dispersed in the electrolyte 26 is reduced to the EC1 dye 24 that has been reduced to generate radicals. Is considered to be attracted (see FIG. 5B).

  When the voltage applied between the electrode 20 and the electrode 18 is further increased and a voltage having the voltage value E2 which is the threshold value of the EC2 dye 28 is applied, the EC2 dye 28 is reduced (FIG. 5C ) See) Change from non-colored state to colored state. At this time, since the EC2 dye 28 has a higher threshold value between the EC1 dye 24 and the EC2 dye 28, it is considered that electrons move between the EC1 dye 24 and the EC2 dye 28 between molecules. By the exchange of electrons between the EC1 dye 24 and the EC2 dye 28, the EC1 dye 24 held in the porous layer 22 is oxidized and decolored, and the EC2 dye 28 is reduced and decolored. It is thought to change to a colored state. For this reason, it is considered that the EC1 dye 24 and the EC2 dye 28 are prevented from being in a colored state at the same time, only the EC1 dye 24 is in a decolored state, and only the EC2 dye 28 is in a colored state.

  On the other hand, when the voltage applied between the electrodes is gradually increased with the electrode 20 side as the positive electrode and the electrode 18 side as the negative electrode, the EC2 dye 28 of the EC1 dye 24 and the EC2 dye 28 is oxidized first. Loses electrons and changes from a colored state to a decolored state. The electrons lost from the EC2 dye 28 due to the transfer of electrons between the EC1 dye 24 and the EC2 dye 28 are received by the EC1 dye 24, and the EC1 dye 24 is reduced to develop the color from the decolored state. It is considered that the state changes to the state and the first color is developed.

  Further, by further gradually increasing the voltage applied between the electrodes with the electrode 20 side as the positive electrode and the electrode 18 side as the negative electrode, the EC1 dye 24 receives more electrons from the EC2 dye 28, and the EC1 dye 24 It seems that it will be in the state which developed the color of. Further, when the voltage is further gradually increased, electrons received by the EC1 dye 24 move to the electrode 20, and the EC1 dye 24 is also considered to change from the colored state to the decolored state.

  As described above, as the EC dye contained in the display element 16, an EC dye that develops colors in a plurality of different colors in the colored state is used, so that a larger number of EC dyes can be used than in the case of using an EC dye that produces a single color. Color display is realized.

  In the above description, a case has been described in which, among the EC1 dye 24 and the EC2 dye 28, only the EC1 dye 24 is used to develop a plurality of types of colors in the color developing state. EC dyes that develop various colors may be used.

  In the above embodiment, the case where each display element 16 contains only two types of EC dyes, EC1 dye 24 and EC2 dye 28, has been described. Good.

In this case, as shown in FIG. 6, as the EC dye, the EC3 dye 40 that develops a color different from the EC1 dye 24 and the EC2 dye 28 is different from the EC1 dye 24, the EC2 dye 28, and the EC3 dye 40. What is necessary is just to make it the structure further provided with the EC4 pigment | dye 42 which colors in color.
In the EC3 dye 40 and the EC4 dye 42, only the EC3 dye 40 is held in the porous layer 22 together with the EC1 dye 24, and the EC4 dye 42 is dispersed in the electrolyte 26 together with the EC2 dye 28. And it is sufficient. As a method for holding the EC3 dye 40 in the porous layer 22, the same method as the method for holding the EC1 dye 24 in the porous layer 22 may be used.

In this case, EC3 dye 40 and EC4 dye 42 are oxidized dyes when EC1 dye 24 and EC2 dye 28 are reduced dyes, and reduced when EC1 dye 24 and EC2 dye 28 are oxidized dyes. Type dye.
Further, in order for the EC3 dye 40 and the EC4 dye 42 to change from the decolored state to the colored state, the threshold voltage applied between the electrode 20 and the electrode 18 satisfies the relationship of the following formula (2): An EC dye may be selected.

    E3 <E4 Formula (2)

  In formula (2), E3 represents the absolute value of the threshold value of the voltage applied between the electrode 20 and the electrode 18 in order for the EC3 dye 40 to change from the decolored state to the colored state, and E4 represents the EC4 dye. 42 indicates the absolute value of the threshold value of the voltage applied between the electrode 20 and the electrode 18 in order to change from the decolored state to the colored state.

  For example, it is assumed that the EC1 dye 24 and the EC2 dye 28 are reduction-type dyes, and the EC3 dye 40 and the EC4 dye 42 are oxidation-type dyes.

In this case, by applying a voltage between the electrodes 20 and 18 so that the electrode 20 side becomes a negative electrode and the electrode 18 side becomes a positive electrode, and the applied voltage is gradually increased, as described above, EC1 It is considered that after the dye 24 dye is brought into a colored state, a color change occurs in which the EC1 dye 24 is brought into a non-colored state and the EC2 dye 28 is brought into a colored state.
At this time, it is considered that the EC3 dye 40 and the EC4 dye 42 remain in a non-colored state because they are oxidized dyes.

  On the other hand, by applying a voltage between the electrodes 20 and 18 so that the electrode 20 side becomes a positive electrode and the electrode 18 side becomes a negative electrode, and the applied voltage is gradually increased, EC1 dyes 24 and EC2 which are reduction-type dyes. The dye 28 is maintained in a non-colored state, and the oxidized dyes EC3 dye 40 and EC4 dye 42 are sequentially changed in color and non-colored states by transferring electrons between molecules in the same manner as the EC1 dye 24 and EC2 dye 28. It is considered that the color development state occurs, and the color in the color development state of each EC dye is selectively displayed.

  As described above, when the EC1 dye 24 and the EC2 dye 28 are oxidation-type dyes, they further contain a reduction-type dye, and when the EC1 dye 24 and the EC2 dye 28 are reduction-type dyes, they further contain an oxidation-type dye. As a result, further multicolor display becomes possible.

  The voltage value and polarity of the voltage for changing each EC dye from the decolored state to the colored state are stored in advance in a memory not shown in the control unit 32 in association with information indicating the color to be displayed. Just keep it. Then, the control unit 32 may output to the voltage application unit 30 an instruction signal indicating application of a voltage having a voltage value and polarity corresponding to the display target color of each display element 16. The voltage application unit 30 to which the instruction signal is input may apply a voltage having a polarity and a voltage value corresponding to the instruction signal between the electrodes 20 and 18. In this way, it is considered that the color of a desired EC dye or the color of a specific color development state of a specific EC dye is selectively displayed on each display element 16.

The voltage applied from the voltage application unit 30 to the electrodes 20 and 18 of each display element 16 is a voltage (for example, a rectangular wave) that changes rapidly toward the threshold voltage value of each EC dye. May be a voltage that changes stepwise or continuously toward the threshold voltage value. As described above, in each display element 16, the EC1 dye 24 (or EC3 dye 40) held in the porous layer 22 and the EC2 dye 28 (or EC4 dye 42) dispersed in the electrolyte 26 are used. When electrons are exchanged between molecules between and, one is decolored and the other is colored. During the transfer of electrons, the display color is likely not to be stable. Therefore, a voltage that changes continuously or stepwise toward the threshold voltage value of each EC dye is applied. Thus, it is considered that color mixing between EC dyes is further suppressed.
Such voltage application is realized by controlling the voltage application unit 30 by the control unit 32.

  As described above, in the color filter 10 of the present embodiment, a plurality of the display elements 16 are arranged between the substrate 12 and the substrate 14 in the surface direction of the substrate. For this reason, a region corresponding to a pixel is defined so as to include a plurality of display elements 16 (for example, three display elements 16), and all of the plurality of display elements 16 corresponding to each pixel have an arbitrary color (for example, By applying a voltage between the electrodes so that (red) is displayed, it is considered that a color filter in which the brightness of each pixel is improved as compared with a conventional color-fixed color filter is provided.

  Further, by selecting the electrochromic dye included in each display element 16 so that the colors in the colored state are red, green, and blue, the application range as a color filter is high, and each pixel It is considered that the color filter 10 with improved brightness is realized.

  That is, in the conventional color filter, as shown in FIG. 7A, an area for extracting only red light, an area for extracting only green light, and an area for extracting only blue light are combined into one pixel. It was defined as the corresponding area. For this reason, each of red, green, and blue is displayed using only an area corresponding to 1/3 of an area corresponding to one pixel.

  On the other hand, according to the color filter 10 of the present embodiment, a plurality of display elements 16 that selectively display the color of the electrochromic dye are arranged in the plane direction of the substrate. Therefore, a plurality of display elements 16 arranged in succession are defined as regions X corresponding to the respective pixels (see FIGS. 2 and 7B), and the display elements 16 included in the regions corresponding to the respective pixels. For all of these (three display elements 16 included in the region corresponding to one pixel in FIG. 7B), the color (for example, red) of the included electrochromic dye in a specific color development state is displayed. Thus, a voltage may be applied between the electrodes 20 and 18 of each display element 16. Then, as shown in FIG. 7B, since red is displayed on all three display elements 16 included in the region X, as a result, the entire region corresponding to one pixel is displayed. It is considered that red is displayed in the area. For this reason, it is considered that the color filter 10 in which the brightness of each pixel is improved as compared with a conventional color-fixed color filter is provided. Further, since the target color is displayed in all the areas corresponding to one pixel, it is considered that high image quality can be realized.

In addition, when displaying secondary colors, it is considered that a color filter in which the brightness of each pixel is improved as compared with a conventional color-fixed color filter is provided. That is, in the conventional color filter, when displaying a secondary color, as shown in FIG. 7C, an area corresponding to 2/3 of an area corresponding to one pixel (for example, a red area and a green area). The secondary color (for example, yellow) was displayed using only the area (1).
On the other hand, according to the color filter 10 of the present embodiment, a plurality of display elements 16 that selectively display the color of the electrochromic dye are arranged in the plane direction of the substrate. For this reason, a plurality of display elements 16 arranged in succession are defined as an area X (see FIGS. 2 and 7D) corresponding to each pixel, and three displays included in the area corresponding to each pixel. A voltage is applied between the electrodes 20 and 18 of the display element 16 so that two of the display elements 16 are displayed in red, and the other display elements 16 included in the region X are used. A voltage is applied between the electrode 20 and the electrode 18 of the display element 16 so that a certain display element 16 is displayed in green. Thus, all the display elements 16 included in the region X corresponding to one pixel are regions that contribute to yellow display, which is a secondary color to be displayed (see FIG. 7D). For this reason, it is considered that the color filter 10 in which the brightness of each pixel is improved as compared with a conventional color-fixed color filter is provided. In addition, since the target color is displayed in all the areas corresponding to one pixel, it is considered that the image quality can be improved.

  Furthermore, the color filter 10 according to the present embodiment has one pixel as compared with the conventional configuration in which the color of the region corresponding to one pixel is made variable by stacking a plurality of layers that develop different colors. Since each of the plurality of display elements 16 constituting the corresponding region selectively displays a color by the contained electrochromic dye, it is compared with a conventional configuration in which a target color is displayed by overlapping colors in the thickness direction. Thus, it is considered that the color filter 10 in which the brightness of each pixel is improved is provided.

  Therefore, it is considered that the brightness of the display is improved in the color filter 10 of the present embodiment as compared with the color filter having the configuration not using the display element 16 of the present embodiment.

  Furthermore, in the color filter 10 of the present embodiment, the display element 16 on which the color of the electrochromic dye contained by voltage application is selectively displayed is arranged in the plane direction of the substrate (substrate 12 and substrate 14). It is set as the structure arranged in multiple numbers. For this reason, in the production of the color filter 10, it is only necessary to arrange a plurality of display elements 16 on the substrate (substrate 12 and substrate 14), and a precise manufacturing process such as an ink jet method is not required as in the case of a conventional color filter. In addition, it is not necessary to separate colors for each pixel. For this reason, it is considered that the manufacturing process can be simplified.

In the color filter 10 of the present embodiment, each display element 16 may be provided with a TFT (thin film transistor) in order to realize active matrix driving of each display element 16. Specifically, as in the color filter 10A shown in FIG. 8A, the electrode 20 is provided for each region corresponding to each display element 16, and the TFT 44 is provided for each electrode 20. Also good. Although illustration is omitted, the electrode 18 on the substrate 14 side may be provided for each region corresponding to each pixel, and a TFT (not shown) may be provided for each electrode 18.
Note that the color filter 10A illustrated in FIG. 8A has the same configuration except that the TFT 44 is provided for each electrode 20 of the color filter 10 illustrated in FIG.

  Further, in the example of the color filter 10 shown in FIG. 1, a mode is shown in which a member for separating the region between the substrate 12 and the substrate 14 is not provided for each display element 16 (see FIG. 1). However, the color filter 10 may be a color filter 10B having a configuration in which a member for separating an area between the substrate 12 and the substrate 14 is provided for each display element 16 (see FIG. 8B).

Specifically, as shown in FIG. 8B, in the color filter 10 shown in FIG. 1 as an example, a gap member 46 that divides a region between the substrate 12 and the substrate 14 for each display element 16 is provided. The color filter 10 may be configured as described above. As a result, movement of the electrolyte 26 between the display elements 16 is prevented.
The color filter 10B shown in FIG. 8B has the same configuration except that the gap member 46 is provided in the color filter 10 shown in FIG. The gap member 46 may be an insulating member. Note that “insulating” indicates that the volume resistivity is 10 ⁹ Ω · cm or more.

Note that the color filter 10 of the present embodiment is preferably provided with a display medium that selectively displays black and white for each region corresponding to each pixel on the side opposite to the display surface side.
Specifically, as shown in FIG. 9, a color filter having a configuration in which a display medium 50 is provided on the back side of the color filter 10 described with reference to FIG. 1 (the side opposite to the substrate 12 that is a display surface). 10C may be used. With this configuration, the color filter 10 can achieve full-color display with black and white display and adjustment of the color (density) of the color displayed on each display element 16.

  Each display element 16 provided in the color filter 10 is transparent when the electrochromic dye is in a non-colored state. Therefore, white display is performed on the display medium to increase the whiteness (whiteness is 30). % Or more, the measurement method will be described later).

  Specifically, as illustrated in FIG. 9, the color filter 10 </ b> C may have a configuration in which the display medium 50 is superimposed on the substrate 14 side of the color filter 10 illustrated in FIG. 1. The display medium 50 includes, for example, an electrode 52, an insulating layer 54, a display layer 56, an insulating layer 58, on the substrate 14 side of the color filter 10, in this order in the direction opposite to the substrate 12 of the color filter 10. The electrode 60 and the substrate 62 may be stacked. The electrode 52 and the electrode 60 may be configured to apply a voltage to each region corresponding to each pixel, and the linear electrode 52 and the linear electrode 60 are regions corresponding to each pixel (for example, FIG. 2). In such a manner that they cross each other in the region X).

  The insulating layer 54 and the insulating layer 58 may be made of an insulating material. The display layer 56 may be configured to selectively move one of white particles and black particles to the display surface side (that is, the electrode 52 side) by applying a voltage to the electrode 52 and the electrode 60. For example, the display layer 56 includes a white layer 56B disposed along the surface direction of the substrate 12, black particles 56A charged to the positive electrode or the negative electrode, and a dispersion medium 56C.

  As the black particles 56A, for example, carbon black, manganese ferrite black, titanium black or the like is used. The white layer 56B is a layer having a whiteness of 30% or more and is configured to have holes through which the black particles 56 pass in the thickness direction. The whiteness is a measure of whiteness, and is specifically a value measured using a Hunter whiteness meter or an X-rite colorimetry system according to the method described in JIS-P8123. The white layer 56B is an aggregate of particulate members made of an inorganic material such as titanium oxide or zinc oxide, or an organic material made of methyl methacrylate, styrene acrylic resin, silicone resin, polytetrafluoroethylene, or the like. It may be a body, a form in which these particles are dispersed in the dispersion medium 56C, or a resin sheet or a nonwoven fabric may be used.

  The electrode 52 and the electrode 60 of the display medium 50 are electrically connected to the voltage application unit 64. The voltage application unit 64 is electrically connected to the control unit 32 described with reference to FIG. In the display medium 50, by applying a voltage from the voltage application unit 64 to the electrode 52 and the electrode 60 corresponding to each pixel under the control of the control unit 32, black or white is applied to the corresponding pixel region of the display medium 50. Will be displayed.

  Therefore, in the color filter 10C, a voltage is applied to the electrode 20 and the electrode 18 corresponding to each of the plurality of display elements 16 provided for each region corresponding to each pixel in the target color filter 10, and the display medium By applying a voltage to the electrode 52 and the electrode 60 corresponding to each of the 50 pixels, adjustment of the color (density) of the color displayed on each display element 16 is realized. Further, it is considered that white display with high whiteness and black display with high blackness are realized.

  Moreover, the color filter 10 of this Embodiment is applied to various display apparatuses.

  The present embodiment will be described more specifically with reference to examples. The scope of the present embodiment is not limited to the specific examples shown below.

Example 1
The color filter shown in FIGS. 2 and 8B was produced by the following operation.

<Adjustment of substrate and electrode>
Two substrates were prepared in which a plurality of linear ITO electrodes having a width of 127 μm were arranged at intervals of 127 μm on a glass substrate having a thickness of 1.1 mm (trade name Corning 1737 manufactured by Corning).

<Adjustment of porous layer>
A substrate on which one of the two substrates is provided on the display surface side (hereinafter referred to as a display substrate) is porous on a linear ITO electrode arrayed on the display substrate. A TiO ₂ porous layer was provided as a layer. Specifically, a TiO ₂ paste (Ti-Nanoxide HT-LALT) manufactured by Solaronix is applied to the ITO electrode to a thickness of 60 μm by a squeegee method, and is heat-treated in the atmosphere at 130 ° C. for 30 minutes. A porous layer was provided on the ITO electrode. The thickness of the obtained TiO ₂ porous layer was about 10 μm.

Regarding the other one of the two substrates (hereinafter referred to as a back substrate), SnO ₂ / Sb (antimony-doped tin oxide) was provided as a porous layer on the back substrate side. Specifically, water (SnO ₂ 30 wt%) and acetylacetone (10 wt% with respect to SnO ₂ ) were added to SnO ₂ / Sb powder (particle diameter 20 nmφ), and the pH was adjusted to about 1.7 with hydrochloric acid. Thereby, a good SnO ₂ aqueous dispersion was obtained. Further, PEG 20000 was added in a paste form by adding 40 wt% with respect to the amount of SnO ₂ . This paste was applied to the ITO electrode to a thickness of 60 μm by a squeegee method, and heat treated in the atmosphere at 450 ° C. for 2 hours or more to provide a porous layer on the ITO electrode of the back substrate. The thickness of the obtained SnO ₂ / Sb porous layer was about 8 μm.

<Adsorption of EC1 dye 24 and EC3 dye 40 to the porous layer>
As the EC1 dye 24, a viologen derivative shown in the following (I) (reduced dye: blue color in the colored state) and as the EC3 dye 40, carboxyfluorescein (oxidized dye: yellow color in the colored state) And prepared.

(I)

A viologen derivative as an EC1 dye is prepared by immersing the display substrate provided with the porous layer of TiO ₂ for 24 hours in a mixed aqueous solution of 2% by mass of this viologen derivative and 2% by mass of carboxyfluorescein. And carboxyfluorescein as EC3 dye were adsorbed on the TiO ₂ porous layer. The display substrate provided with the above TiO ₂ porous layer was a 30-minute heat treatment at 120 ° C. prior to immersion.

<Adjustment of electrolyte>
As an electrolytic solution constituting the electrolyte, a tetrabutylammonium perchlorate (TBAP) 50 mM / ferrocene 50 mM / propylene carbonate (PC) solution was used.
In this electrolytic solution, as EC2 dye 28, dimethyl terephthalate (DTP) represented by the following formula (II) (reduced dye: colored in a colored state is red) is prepared and dissolved in the electrolytic solution at a concentration of 50 mM. I let you.

<Production of color filter>
On the display substrate provided with the TiO ₂ porous layer on which both the viologen derivative as the EC1 dye 24 and carboxyfluorescein as the EC3 dye are adsorbed, between the display substrate and the back substrate ( In FIG. 8B, a gap member 46 is formed for separating the display element 16 between the substrate 12 and the substrate 14.
Specifically, after applying a UV curable resin (trade name: NIF-A-1 manufactured by Asahi Glass Co., Ltd.) to a thickness of 50 μm as a constituent material of the gap member 46 on the surface substrate, the gap member to be formed is applied. UV exposure was carried out through a mask pattern formed so that light was irradiated only to the area | region corresponded to. As a result, only the exposed region of the ultraviolet curable resin applied on the display substrate was cured. Thereafter, the uncured ultraviolet curable resin was removed by washing, whereby the gap member 46 was formed on the display substrate. Since the cured ultraviolet curable resin penetrated into the porous layer, the porous layer was divided by the gap member 46 so that the electrolyte solution was not moved.

  In addition, as a mask pattern formed so that light is irradiated only to the region corresponding to the gap member to be formed, a region of 244 μm × 752 μm (region corresponding to each display element, ie, Example 1) In this example, a pattern arranged in a grid pattern with an interval of 10 μm (corresponding to the width of the gap member 46) is used.

  Next, the display substrate on which the gap member 46 is formed, the back substrate, the side of the display substrate on which the gap member is provided, and the side of the back substrate on which the porous layer is provided are stacked so as to face each other. After the combination, the electrolytic solution in which DTP as the EC2 dye 28 and ferrocene as the redox agent were dispersed was filled in the region defined by the display substrate, the back substrate, and the gap member. Thus, the color filter shown in FIG. 8B was adjusted.

  That is, a color filter in which a plurality of display elements are arranged is adjusted between the display substrate and the back substrate.

  Each display element of the color filter was transparent when no voltage was applied.

  And about each display element, when the voltage was applied to the ITO electrode by the side of a display board | substrate and the ITO electrode by the side of a back substrate, the ITO electrode by the side of a back substrate is set to 0V, and -1. When a voltage of 5 V was applied, a blue color due to the viologen derivative as EC1 dye 24 was confirmed.

  For each display element, when the ITO electrode on the back substrate side was set to 0 V and a voltage of −3.0 V was applied to the ITO electrode on the display substrate side, the blue color due to the viologen derivative as the EC1 dye 24 disappeared, and EC2 The red color of DTP as the dye 28 was confirmed.

  Further, for each display element, when the ITO electrode on the back substrate side was set to 0 V and a voltage of +3.0 V was applied to the ITO electrode on the display substrate side, the blue color by the viologen derivative as the EC1 dye 24 and the EC2 dye 28 Both red colors of DTP were erased, and yellow color due to carboxyfluorescein as EC3 dye 40 was confirmed.

―Evaluation of brightness―
With respect to the adjusted color filter, three consecutive display elements are set as one pixel, and a voltage is applied to all of the three consecutive display elements as described above so that blue, red, yellow, Each of them was displayed. Thereby, each of blue, red, and yellow was displayed on all the display elements included in the region corresponding to one pixel.

  Next, a reflection type monochrome display medium (manufactured by Sony, LIBRLe) was prepared.

Next, the color filter adjusted in the first embodiment is placed on the reflective black-and-white display medium, and three continuous display elements are defined as one pixel, and all the three continuous display elements are The voltage was applied as described above to display the red color of DTP as the EC2 dye 28.
At this time, the reflective black-and-white display medium is in a state of displaying white.
And the reflectance (density) of the area | region corresponding to this pixel was 0.8 when it measured by X-rite404 by X-rite. The reflectance (density) was measured from the display substrate side of the color filter.

  In addition, the color filter adjusted in the first embodiment is mounted on the reflection type black and white display medium in a state where white display is performed, and the three continuous display elements are set as one pixel. A voltage was applied to all the display elements as described above to display a blue color with a viologen derivative as the EC1 dye 24. The reflectance of the region corresponding to this pixel was measured from the display substrate side by X-rite 404 manufactured by X-rite, and found to be 0.8.

  In addition, the color filter adjusted in the first embodiment is mounted on the reflection type black and white display medium in a state where white display is performed, and the three continuous display elements are set as one pixel. A voltage was applied to all the display elements as described above to display yellow color due to carboxyfluorescein as the EC3 dye 40. The reflectance of the region corresponding to this pixel was measured from the display substrate side of the color filter by X-rite 404 manufactured by X-rite Co., Ltd.

  It should be noted that the reflectance of the region corresponding to each of the displayed pixels of red, blue, and yellow is measured with five different reflections for the entire region in each pixel by the X-rite 404 manufactured by X-rite. The rate was measured, and the average value of the results was determined as the reflectance.

(Comparative Example 1)
In Example 1, a color filter having a configuration in which a plurality of display elements that selectively develop colors of three colors of red, yellow, and blue was arranged.
On the other hand, in the first comparative example, a display element that develops color only in red, a display element that develops color only in yellow, and a display element that develops color only in blue are displayed as a plurality of display elements corresponding to one pixel region. A comparative color filter having a configuration in which a plurality of these three display elements are arranged as one unit was used.

  Specifically, it was produced by the following operation.

<Adjustment of substrate and electrode>
Two substrates were prepared in which a plurality of linear ITO electrodes having a width of 127 μm were arranged at intervals of 127 μm on a glass substrate having a thickness of 1.1 mm (trade name Corning 1737 manufactured by Corning).

A substrate on which one of the two substrates is provided on the display surface side (hereinafter referred to as a display substrate) is porous on a linear ITO electrode arrayed on the display substrate. A TiO ₂ porous layer was provided as a layer. Specifically, a TiO ₂ paste (Ti-Nanoxide HT-LALT) manufactured by Solaronix is applied to the ITO electrode to a thickness of 60 μm by a squeegee method, and is heat-treated in the atmosphere at 130 ° C. for 30 minutes. A porous layer was provided on the ITO electrode. The thickness of the obtained TiO ₂ porous layer was about 10 μm.

Regarding the other one of the two substrates (hereinafter referred to as a back substrate), SnO ₂ / Sb (antimony-doped tin oxide) was provided as a porous layer on the back substrate side. Specifically, water (SnO ₂ 30 wt%) and acetylacetone (10 wt% with respect to SnO ₂ ) were added to SnO ₂ / Sb powder (particle diameter 20 nmφ), and the pH was adjusted to about 1.7 with hydrochloric acid. Thereby, a good SnO ₂ aqueous dispersion was obtained. Further, PEG 20000 was added in a paste form by adding 40 wt% with respect to the amount of SnO ₂ . This paste was applied to the ITO electrode to a thickness of 60 μm by a squeegee method, and heat treated in the atmosphere at 450 ° C. for 2 hours or more to provide a porous layer on the ITO electrode of the back substrate. The thickness of the obtained SnO ₂ / Sb porous layer was about 8 μm.

On the display substrate provided with the porous layer, a gap member for separating the display substrate and the back substrate for each display element was formed.
Specifically, an ultraviolet curable resin (trade name: NIF-A-1 manufactured by Asahi Glass Co., Ltd.) was applied to the surface substrate as a constituent material of the gap member to a thickness of 50 μm, and then used in Example 1. UV exposure was performed through the mask pattern. As a result, only the exposed region of the ultraviolet curable resin applied on the display substrate was cured. Thereafter, the uncured ultraviolet curable resin was removed by washing to form a gap member on the display substrate. Since the cured ultraviolet curable resin penetrated into the porous layer, the porous layer was divided by the gap member so that the electrolyte solution was not moved.

  Next, a plurality of regions separated by the gap member were determined as three regions corresponding to one pixel. Then, a 2% by mass aqueous solution of the viologen derivative (reduced dye: the color in a colored state is blue) shown in (I) above is applied to the porous layer of one of the three regions corresponding to each pixel. By dropping and allowing to stand for 24 hours, the viologen derivative as the EC1 dye was adsorbed to the porous layer in the region. Thereafter, this region was filled with the electrolytic solution used in Example 1.

  In addition, a 2% by mass aqueous solution of carboxyfluorescein (oxidized dye: yellow color when colored) is dropped into one of the remaining two areas corresponding to the pixel. For 24 hours, carboxyfluorescein was adsorbed on the porous layer in the region. Thereafter, this region was filled with the electrolytic solution used in Example 1.

  In addition, EC dye is not adsorbed in the porous layer of the remaining one region among the three regions corresponding to the pixel, and the electrolytic solution used in Example 1 is represented by the above formula (II). A liquid prepared by dissolving dimethyl terephthalate (DTP) (reduced dye: red color when colored) in an electrolyte solution at a concentration of 50 mM was filled.

  Next, the display substrate on which the gap member 46 is formed, the back substrate, the side of the display substrate on which the gap member is provided, and the side of the back substrate on which the porous layer is provided are stacked so as to face each other. The comparative color filter was adjusted by sealing together.

  Each display element of the comparative color filter was transparent when no voltage was applied.

―Evaluation of brightness―
The comparative color filter adjusted in this comparative example 1 is placed on the “reflective black-and-white display medium with white display” prepared in Example 1, and the ITO electrode on the back substrate side is set to 0 V, and the display substrate side When a voltage of −3.0 V was applied to the ITO electrode, two of the three types of display elements were transparent, and only one type of display element was confirmed to be red in DTP.
The reflectance (density) of an area composed of these three types of display elements (area corresponding to one pixel) was measured by X-rite 404 manufactured by X-rite, and found to be 0.3. The reflectance (density) was measured from the display substrate side of the comparative color filter.

Further, the comparative color filter adjusted in this comparative example 1 is placed on the “reflective black and white display medium in a white display state” prepared in Example 1, the ITO electrode on the back substrate side is set to 0 V, and the display is performed. When a voltage of −1.5 V was applied to the ITO electrode on the substrate side, two of the three types of display elements remained transparent, and only one type of display element was confirmed to be blue due to the viologen derivative.
The reflectance (density) of an area composed of these three types of display elements (area corresponding to one pixel) was measured by X-rite 404 manufactured by X-rite, and found to be 0.3. The reflectance (density) was measured from the display substrate side of the comparative color filter.

Further, the comparative color filter adjusted in this comparative example 1 is placed on the “reflective black and white display medium in a white display state” prepared in Example 1, the ITO electrode on the back substrate side is set to 0 V, and the display is performed. When a voltage of +3.0 V was applied to the ITO electrode on the substrate side, two of the three types of display elements were transparent, and yellow of carboxyfluorescein was confirmed only in one type of display element.
The reflectance (density) of an area composed of these three types of display elements (area corresponding to one pixel) was measured by X-rite 404 manufactured by X-rite, and found to be 0.25. The reflectance (density) was measured from the display substrate side of the comparative color filter.

  In addition, the measurement of the reflectance of the area | region corresponding to said one pixel measured the reflectance of five different points about all the areas in each pixel with said X-rite 404 by the said X-rite, and average value of the result Was determined as the reflectance.

  As described above, in Example 1, the reflectance when each of red, blue, and yellow is displayed in the region corresponding to each pixel is higher than that of the comparative example (about 2.6 times). The result was obtained. For this reason, it can be said that the brightness of each pixel was improved in the color filter of Example 1 compared to the comparative color filter adjusted in Comparative Example 1.

10, 10A, 10B, 10C Color filter 12 Substrate 14 Substrate 16 Display element 18 Electrode 20 Electrode 22 Porous layers 24, 28, 40, 42 Electrochromic dye 26 Electrolyte

Claims (3)

A pair of substrates;
A plurality of display elements provided between the pair of substrates and arranged in a surface direction of the substrate;
Have
Each of the plurality of display elements is
A first electrode provided on one substrate side of the pair of substrates, a second electrode provided on the other substrate side of the pair of substrates, the first electrode, and the first electrode An electrolyte disposed between the two electrodes, a conductive or semiconductive porous layer disposed on one of the opposing surfaces of the first electrode and the second electrode, and the porous And a first electrochromic dye dispersed in the electrolyte and having a color different from that of the first electrochromic dye. The first electrochromic dye Both the chromic dye and the second electrochromic dye are oxidized dyes that are colored by an electrochemical oxidation reaction and decolored by a reduction reaction, or reductions that are colored by an electrochemical reduction reaction and are decolored by an oxidation reaction Mold dye The voltage applied between the first electrode and the second electrode in order to change from the decolored state to the colored state of the first electrochromic dye and the second electrochromic dye. A display device whose threshold value satisfies the relationship of the following formula (1).
E1 <E2 Formula (1)
(In Formula (1), E1 is the voltage applied between the first electrode and the second electrode in order for the first electrochromic dye to change from the decolored state to the colored state) Indicates the absolute value of the threshold,
E2 represents the absolute value of the threshold value of the voltage applied between the first electrode and the second electrode in order for the second electrochromic dye to change from the decolored state to the colored state. )   At least one of the first electrochromic dye and the second electrochromic dye is colored in a plurality of different colors in the colored state, and the first electrode and the The display device according to claim 1, wherein thresholds of voltages applied between the second electrode and the second electrode are different from each other.   3. The display device according to claim 1, wherein a color of the first electrochromic dye and the second electrochromic dye in the color developing state is any one of red, green, and blue.