JP2001188264A - Electrochromic display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrochromic display device capable of obtaining sufficient color density and high speed of display response. SOLUTION: The electrochromic display device has an electrochromic material layer 3 and a molten salt electrolyte layer 4 which are interposed between a first and a second transparent electrodes 2 and 5 opposed to each other. The electrochromic material layer has a fine and a rugged structure on its surface and <=100 nm film thickness. And the specific surface area of the surface of the electrochromic material layer is >=100.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an electrochromic display device.

[0002]

2. Description of the Related Art Conventionally, an electrochromic display element for displaying information by utilizing a redox reaction of an electrochromic material (hereinafter referred to as an EC material) has been known. This electrochromic display element has a transparent electrode,
It has a laminated structure in which an EC material layer, an electrolyte layer, and a counter electrode are laminated in this order. The electrochromic display element applies a voltage between the transparent electrode and the counter electrode, and the generated electric field causes ions in the electrolyte to diffuse through the electrolyte and reach the EC material. To reduce. This causes a color change of the EC material, which is used for display.

However, in the conventional electrochromic display device, the response speed of the EC material after applying a voltage between the electrodes is extremely slow, about 10 seconds to 1 second, so that it cannot be used as a display material requiring a high-speed response. It was difficult.

[0004] The display response of the EC material is determined by the diffusion of ions in the electrolyte and the diffusion of ions in the EC material after the ions reach the EC material. In order to increase the response speed of the electrochromic display element, for example, in Japanese Patent Application Laid-Open No. 57-11326, a thin film EC material is provided on the display electrode to increase the speed. Time has not been reduced.

Further, if the thickness of the thin film of the EC material is reduced, the ion diffusion distance in the EC material can be reduced and the speed can be increased. The required density of color cannot be obtained.

Further, in Japanese Patent Application Laid-Open No. 58-38930, the effective surface area is enlarged by forming the EC material layer to be porous, thereby realizing high-speed response. However, the time required for ion diffusion in the porous material is not reduced.

[0007]

As described above, in the conventional electrochromic display device, diffusion of ions used for a color change reaction is problematic, and it has been difficult to increase the display speed. There are two types of ion diffusion in an electrochromic display element: ion diffusion in an electrolyte and ion diffusion in an electrochromic material. If both are not increased, the display speed cannot be improved. Therefore, even if the shape of the EC material layer is improved, it has been difficult to achieve both the problem of ion diffusion in the electrolyte, the acquisition of the color density required for display, and the high-speed display response.

An object of the present invention is to provide an electrochromic display element which can obtain a sufficient color density and can speed up a display response, in view of the above points.

[0009]

In order to achieve the above object, an electrochromic display device according to the present invention comprises:
An electrochromic material layer having a fine uneven structure on the surface and having a thickness of 100 nm or less, a molten salt electrolyte layer in contact with the surface of the electrochromic material layer, and an electrochromic material layer and a molten salt electrolyte layer interposed therebetween. And first and second electrodes disposed to face each other.

In the above-described electrochromic display device, the fine uneven structure means that the surface structure is not flat but has an uneven structure, and the effective surface area is larger than the apparent element area. The concavo-convex structure may be a structure in which a number of fine holes are formed, a structure having a number of fine columnar projections, or a dendritic structure, a fibrous structure, or any other three-dimensional structure. it can. The pitch and height of the unevenness are 100 n.
m or less.

The electrochromic material is made of a material that undergoes a color change by performing an oxidation-reduction reaction with ions in the electrolyte layer. The electrochromic material layer is very thin and is formed to 100 nm or less. The surface of the electrochromic material layer having the concavo-convex structure preferably has a large effective surface area. Specifically, the surface area (substantial area / planar area) is preferably 50 or more.

Since the electrochromic material layer has a fine uneven structure, the surface of the electrochromic material to which ions diffused from the electrolyte layer can reach is increased, and a large amount of electrochromic material near the surface is quickly formed. The ions can reach and the response speed of the color change is improved.

The term "molten salt electrolyte" indicates that ions themselves that contribute to the electrochromic reaction constitute the electrolyte itself without containing a solvent. Conventionally used electrolytes in which ions are dissolved in a solvent cannot increase the ion concentration beyond the saturation concentration of the solution. Process
It takes a long time to respond.

However, when the electrolyte has a molten salt structure and is provided in contact with the electrochromic material layer, ions in the molten salt can react immediately when a driving voltage is applied to the electrochromic display element. In addition, the time required for ion diffusion can be reduced.

Further, an electrochromic display element according to the present invention comprises: a first electrode having a fine uneven structure on a surface; and an electrochromic material layer provided on the surface of the first electrode and having a thickness of 10 nm or less. A molten salt electrolyte layer in contact with the electrochromic material layer, and a second electrode facing the first electrode with the electrochromic material layer and the molten salt electrolyte layer interposed therebetween. I have.

In the above-mentioned electrochromic display element, the fine structure electrode means that the surface of the electrode is not flat but has an uneven structure, and the effective surface area is larger than the apparent flat area. The concavo-convex structure may be a structure having a large number of fine holes, a structure having a large number of fine columnar projections, a dendritic structure, a fibrous structure, or any other three-dimensional structure. It is desirable that the pitch and the height of the unevenness be 100 nm or less.

The electrochromic material is made of a material that undergoes a redox reaction with ions in the electrolyte layer to cause a color change. The electrochromic material layer is very thin and is formed to a thickness of 10 nm or less, preferably 5 nm or less. For example, when the electrochromic material is an organic low-molecular material, the electrochromic material layer is preferably a monomolecular layer.

When the electrochromic material layer is thin,
After the ions diffused from the electrolyte layer reach the electrochromic material layer, the ions can quickly reach the entire electrochromic layer, and the response speed of the color change is improved.

However, when the electrode surface is flat, the absolute amount of the electrochromic material is reduced by thinning the electrochromic layer, and a desired color density cannot be obtained. Therefore, according to the present invention, as described above, the electrode surface in contact with the electrochromic material layer has a fine uneven structure and has an increased surface area.

The color density can be adjusted depending on the size of the surface area of the electrode. That is, when the electrochromic material layer has the same thickness, the larger the surface area is, the darker the color can be displayed.

It is desirable that the electrode having the concavo-convex structure and the electrochromic material layer are chemically bonded, but may be physically adsorbed only by intermolecular attraction. Therefore,
In order to prevent the electrochromic material layer from agglomerating to an unnecessarily thick thickness, it is preferable that the molecular structure of the electrochromic material contains a functional group capable of chemically bonding to an electrode surface having a fine uneven structure.

In this case, one or more molecular layers of the electrochromic material cannot be chemically bonded to the electrode surface.
A uniform monomolecular electrochromic material layer can be provided on the electrode surface. The electrode and the thin-film electrochromic material layer provided on the surface thereof are in contact with the above-mentioned molten salt electrolyte.

As described above, according to the present invention, by disposing a high concentration of ions in the vicinity of the electrochromic material using the molten salt electrolyte, it is possible to solve the problem of ion diffusion in the electrolyte. In addition, by reducing the thickness of the electrochromic material layer to 10 nm or less and shortening the time required for ions to diffuse from the surface of the electrochromic material layer to the inside, the problem of ion diffusion control in the electrochromic material layer can be solved. . Furthermore, by increasing the effective surface area of the electrochromic material layer by forming the electrode surface or the electrochromic material layer surface as a fine uneven structure, it is possible to solve the insufficient color density due to the thinning of the electrochromic material layer. Thus, it is possible to provide an electrochromic display element having a high-speed response and a sufficient color density.

Further, an electrochromic display element according to the present invention comprises: an electrochromic material layer; an electrolyte layer in contact with the surface of the electrochromic material layer;
An electrochromic display unit layer having first and second transparent electrodes opposed to each other with the electrochromic material layer and the electrolyte layer interposed therebetween is formed by laminating at least two layers in the display direction. And

Here, the electrochromic display unit layer (hereinafter, referred to as an EC display unit layer) is a component of a multilayer electrochromic display element obtained by laminating these EC display unit layers. And a thin-film electrolyte layer and a thin-film EC material layer provided between these transparent electrodes. The color changes from transparent to translucent coloring by applying a voltage between the transparent electrodes. .

The thin-film electrolyte layer refers to an electrolyte layer having a thickness which can sufficiently respond to a required response speed of an electrochromic display element. The thinner the electrolyte layer, the shorter the ion diffusion time in the layer. For example, a film thickness of 1 μm or less is required to achieve a response speed of 10 ms of the electrochromic display element.

The thin film EC material layer is a thin EC material layer which can sufficiently respond to the required response speed of the electrochromic display element. The EC material layer is
The thinner the film thickness, the shorter the diffusion time for the ions to spread throughout the layer. For example, in order to achieve a response speed of 10 ms of the electrochromic display element, a film thickness of 1 μm or less is required, and preferably 50 nm or less.

It is not necessary for all the EC materials in the EC display unit layer to participate in color development and decoloration. For example, only the EC material portion on the very surface in contact with the electrolyte layer may be colored.

The response speed of the EC display unit layer, the color density,
That is, the relationship between the light absorption rate near the peak value of the light absorption spectrum in the color-developed state of the EC material and the light absorption rate is large at the moment when a voltage is applied between the transparent electrodes,
After that, the rate of change of the light absorptivity gradually becomes slow. This is because redox of the EC material in the vicinity of the electrolyte layer occurs at high speed because the diffusion time of ions is short, but diffusion of ions in the EC material takes a long time in a portion of the EC material that is away from the electrolyte layer. This is because the reaction is slow. Similarly, when the color is erased, the change in the light absorption rate of the EC display unit layer is fast at the time of rising, but the change in the light absorption rate becomes slower as the saturation value is approached.

For a fast electrochromic reaction, only EC materials that can react within the required response time need to be involved in color development and decoloration, and other EC materials do not participate in color development and decoloration. May be.

As described above, it is effective to reduce the thickness of the electrolyte layer and the EC material layer in the electrochromic display element in order to increase the speed of the electrochromic display element.
The content per unit element area of the material cannot be sufficiently obtained, and the color density does not increase. Therefore, the present invention is characterized in that two or more EC display unit layers are stacked to make the overall color density sufficient. The color density required for an electrochromic display element is
The sum of the EC materials in each stacked EC display unit layer may be sufficient, and the amount of the EC material in each EC display unit layer may be small. Therefore, an electrochromic display element having a high response speed and a sufficient color development amount can be obtained.

Further, by changing the content of the EC material in each EC display unit layer, it is easy to multi-value a color such as an intermediate color. That is, for example, when four monochrome EC display unit layers are considered, the ratio of the EC material content in each EC display unit layer is a factorial of 2, for example, a ratio of 1: 2: 4: 8. By selectively controlling ON and OFF of each EC display unit layer, color development in 16 steps is possible. An EC display unit layer capable of forming such an intermediate color is, for example,
A multi-color electrochromic display element capable of full-color development can be obtained by fabricating yellow, cyan, and magenta and laminating them.

In another electrochromic display element according to the present invention, an electrochromic material layer, an electrolyte layer in contact with the surface of the electrochromic material layer, and an opposing arrangement with the electrochromic material layer and the electrolyte layer interposed therebetween. An electrochromic display unit layer having the first and second transparent electrodes is wound around the transparent support a plurality of times to form a roll structure.

According to the electrochromic display device having the above structure, the EC display unit layer is wound around the transparent support to form a roll structure, thereby obtaining a multilayer structure in which a plurality of EC display unit layers are stacked in the display direction. . In particular, in the case of obtaining a multilayer structure having a large number of layers, it is possible to easily manufacture an electrochromic display element by using a roll structure.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electrochromic display device according to an embodiment of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the electrochromic display element according to the first embodiment of the present invention is disposed to face each other with a gap therebetween, and has a first transparent substrate 1 made of glass or the like. 2 includes a transparent substrate 6. On the inner surface of the first transparent substrate 1, a transparent electrode 2 made of a transparent conductive film and functioning as a first electrode is formed. On the inner surface of the second transparent substrate 6, a counter electrode 5 made of a transparent conductive film and functioning as a second electrode is formed. An electrochromic material layer (hereinafter, referred to as an EC material layer) 3 and a molten salt electrolyte layer 4 are sequentially formed on the transparent electrode 2, and are sandwiched between the transparent electrode 2 and the counter electrode 5. The surface of the EC material layer 3 has a fine uneven structure.

As shown in FIG. 2, an electrochromic display device according to a second embodiment of the present invention has a first transparent substrate 1, a transparent electrode 2, an EC material, as in the first embodiment. It comprises a layer 3, a molten salt electrolyte layer 4, a counter electrode 5, and a second transparent substrate 6. According to the second embodiment, the surface of the transparent electrode 2 has a fine uneven structure, and the electrochromic material layer 3 formed on the surface of the transparent electrode 2 also has the fine uneven structure. Has become.

In the first and second embodiments, the material of the transparent conductive film forming the transparent electrode 2 is preferably a conductive polymer or an inorganic transparent conductor. As the conductive polymer, for example, polyaniline, polythiophene, polypyrrole, polythienylene, polyfuran, polyselenophene, polyphenylene, polyN-vinylcarbazole, and the like, and derivatives thereof are preferable.

In the case of a metal oxide semiconductor, the material of the transparent conductive film is a transition metal oxide such as titanium, zirconium, hafnium, strontium, zinc, tin, indium, yttrium, lanthanum, vanadium, niobium, tantalum, Oxide of chromium, molybdenum, tungsten, SrTiO ₃ , CaTiO ₃ , BaTiO ₃ , M
gTiO _3, perovskite such as SrNb ₂ O _6,
Alternatively, these composite oxides or oxide mixtures, Ga
N and the like are preferable.

In the second embodiment, in order to obtain a fine structure on the surface of the transparent electrode 2, for example, in the case of a conductive polymer, processes such as electrolytic polymerization, etching, heat treatment, and light irradiation are used. For the transparent electrode 2, a sol-gel method, fine particle sintering, sputtering, vapor phase growth, or the like is preferable, and a process such as etching, heat treatment, or light irradiation may be performed after the film is formed. Alternatively, a fine surface unevenness structure can be formed by a method of enclosing a binder made of organic fine particles at the time of forming the transparent conductive film and removing the binder by heat treatment later.

The EC material layer 3 is a material characterized by causing a color change by an oxidation-reduction reaction, and is a thin film or a transparent conductive film 2 which can cover the surface of the fine uneven structure of the transparent electrode 2. It has adsorptive properties.

Here, the term “thin film” refers to a material which is polymerized by polymerization or an amorphous material which has a property of preventing agglomeration on the transparent electrode surface due to crystallization and forming a uniform solid. Is desirable. The adsorptivity indicates that the material has a functional period in which a chemical bond can be formed with the transparent electrode surface. The functional period is preferably a carboxyl group, a hydroxydialkyl group, a hydroxyl group, a sulfone group, a carboxyalkyl group, or the like.

The sensitizing dye contained in the EC material layer 3 includes ruthenium tris, ruthenium-bis, osmium tris, an osmium-pis type transition metal complex, a polynuclear complex, a ruthenium-cis diaqua bipyridyl complex, or a phthalocyanine dye It is desirable to use a structure having the above functional group in a naphthalocyanine dye, porphyrin dye, perylene dye, anthraquinone dye, azo dye, quinophthalone dye, naphthoquinone dye, cyanine dye, merocyanine dye, or a mixture thereof.

The monomers constituting the above-mentioned conductive polymer, that is, aniline, thiophene, pyrrole, and derivatives thereof having a structure having the above-mentioned functional period are used.
After being adsorbed on the surface of the fine uneven structure of the transparent electrode 2, an EC material layer may be produced electrochemically by oxidative polymerization.
In this method, only one molecular layer is adsorbed on the surface of the transparent electrode and the monomer is polymerized, so that a monomolecular electrochromic layer can be easily produced. In the conventional method of performing electropolymerization of the transparent electrode surface in a monomer solution,
It is difficult to control the thickness of the EC material layer 3, and the above method is more preferable.

As the molten salt electrolyte 4, a sulfonimide salt, an alkyl imidazolium salt, a tetracyanoquinodimethane salt, a dicyanoquinodiimine salt, or the like is used. Also,
A polymer in which the above-described salt is bonded to a polymer side chain such as polyethylene oxide, polyethylene oxide or polyethylene is used as a molten salt solid electrolyte, and is desirably used when solidifying an electrochromic display element.

The counter electrode 5 may be a metal plate or a transparent substrate provided with a metal thin film, or a transparent substrate provided with a transparent conductive film.

In the first and second embodiments, a light scattering layer (not shown) may be provided in the molten salt electrolyte 4 in order to increase the contrast of display colors. The light-scattering layer is provided so as to cover the portion from the EC material layer where the color change occurs, and has a function of increasing the color contrast by scattering or reflecting light, and furthermore, the ions in the electrolyte from the counter electrode 5. It is necessary to have ion conductivity so that it can move to the EC material layer 3. As the material of the light diffusion layer, fine particles of a metal oxide such as TiO ₂ or Al ₂ O ₃ having a fine particle size of 300 nm or more and strong light scattering properties, or a porous insulating polymer are preferable.

Further, in order to prevent a short circuit due to contact between the counter electrode 5 and the EC material layer 3, spacers such as polymer beads, glass spheres, and glass tubes may be arranged in the molten salt electrolyte layer 4. Next, Example 1 corresponding to the above-described first embodiment and Example 2 corresponding to the above-described second embodiment.
Will be described.

[0049]

Embodiment 1 First, a transparent conductive substrate formed by forming a 0.1 μm thick ITO film as a transparent electrode 2 on a surface of a glass substrate by a sputtering method is prepared.
Materials: 1M thiophene, 0.1M LiClO ₄
Oxidative polymerization was performed at a voltage of 2.5 V versus a saturated calomel electrode (vs. SCE) in an acetonitrile solution containing, and a 100 nm thick polythiophene film was obtained as the EC material layer 3. Scanning electron microscope (SE)
When observed in M), a fiber structure with a diameter of about 10 nm was observed. The surface area of the surface of the EC material layer measured by nitrogen gas adsorption was 500.

Next, a transparent substrate 1 on which an EC material layer 3 is formed and a transparent substrate 6 on which a 1 μm thick ITO film is formed on a glass substrate surface as a counter electrode 5 are provided with spacers of polymer beads having a diameter of 10 μm. And the surroundings were hardened with epoxy resin except for the electrolyte inlet.

As the electrolyte layer, a molten salt obtained by mixing pyridine and butyl iodide in an equimolar amount and dry-distilling at 110 ° C. for 8 hours was used. This molten salt was sealed between the transparent substrate and the electrolyte sealing opening under reduced pressure, and the sealing opening was sealed with an epoxy resin to obtain an electrochromic display element.

[0052]

Embodiment 2 First, a transparent conductive substrate was prepared by forming an ITO film having a thickness of 1 μm as a transparent electrode 2 on the surface of a glass substrate by a sputtering method, and this transparent conductive substrate was immersed in 1N sulfuric acid for 30 seconds. The substrate was immersed and subjected to an etching treatment to obtain a transparent substrate 1 having a transparent electrode 2 having a fine uneven structure. After taking out the transparent substrate 1 and washing it with water, the surface area of the transparent electrode 2 was measured by nitrogen gas adsorption to be 500.

When the surface shape of the transparent electrode 2 was observed with a scanning electron microscope, a fine pore structure having a diameter of 10 nm to 100 μm was confirmed.

Subsequently, the transparent conductive substrate was used as an EC material and 1
M in thiophene-3-sulfonic acid in absolute ethanol
Soak for about 10 hours and adsorb EC material on the surface of transparent electrode 2
I let it. Take out the transparent conductive substrate and wash it with absolute ethanol
After purification, 0.1M LiClO ₄Acetonitrile solution containing
Anodize at 1.5V vs SCE voltage in the solution
The C materials are polymerized on the surface of the transparent electrode 2 and absorbed by the transparent electrode.
A monomolecular film of the EC material deposited, that is, a film thickness of 10 nm
The following EC material layer 3 was obtained.

Next, the transparent substrate 1 on which the EC material is adsorbed,
1 μm thick ITO on the glass substrate surface as the counter electrode 5
The transparent substrate 6 on which the film was formed was opposed to each other via a 1-μm-diameter polymer bead spacer, and the surroundings were hardened with an epoxy resin except for the electrolyte inlet.

As the electrolyte, the same molten salt as in Example 1 was used, and the electrolyte was sealed between the transparent substrates 1 and 6 as in Example 1, and the electrolyte inlet was sealed to obtain an electrochromic display element. Was.

[0057]

COMPARATIVE EXAMPLE 1 A transparent conductive film substrate formed in the same manner as in Example 1 was prepared by using 1M thiophene and 0.1M L as EC materials.
Oxidative polymerization was performed in an acetonitrile solution containing iClO ₄ at a voltage of 1.0 V lower than in Example 1 vs. SCE, and E
A polythiophene film having a thickness of 100 nm was obtained as a C material layer. When the surface shape of the EC material layer was observed by SEM,
It was flat.

Subsequently, a transparent conductive substrate having an EC material layer formed thereon and a 1 μm thick I
The transparent conductive substrate on which the TO film was formed was disposed to face via a spacer of polymer beads having a diameter of 10 μm, and the surroundings were hardened with an epoxy resin except for the electrolyte inlet.

As an electrolyte, a 1 M LiClO ₄ solution of acetonitrile was sealed in the device, and the electrolyte inlet was sealed with an epoxy resin to obtain an electrochromic display device.

With respect to the three types of electrochromic display elements obtained in Examples 1, 2, and Comparative Examples, light having a wavelength of 600 nm was transmitted and the change in transmitted light intensity was examined. When the speed was measured, Example 1 was 100 ms, Example 2 was 20 ms, Comparative Example 1 was 10 s, and it was found that a high-speed electrochromic display element was obtained by the present invention.

Next, an electrochromic display device according to a third embodiment of the present invention will be described. FIG.
As shown in this, the electrochromic display element
An electrochromic display unit layer (hereinafter, referred to as an EC display unit layer) 10 is formed by laminating a plurality of layers along the display direction, for example, three layers.

Each EC display unit layer 10 is opposed to each other with a gap therebetween, and has a first transparent substrate 1 and a second transparent substrate 6 each made of glass or the like. On the inner surface of the first transparent substrate 1, a first transparent electrode 2 made of a transparent conductive film is formed. On the inner surface of the second transparent substrate 6, a counter electrode 5 made of a transparent conductive film and functioning as a second transparent electrode is formed. An EC material layer 3 and an electrolyte layer 4 are sequentially formed on the first transparent electrode 2, and are sandwiched between the first transparent electrode 2 and the counter electrode 5. Note that the first transparent substrate 1 and the second transparent substrate 6 in the two adjacent EC display unit layers 10 are formed of a common transparent substrate.

In each EC display unit layer 10, the first and second transparent substrates 1 and 6 may be made of any material as long as they are transparent plates or sheets, and examples thereof include glass and polymer films.

The material of the transparent conductive film forming the transparent electrode 2 and the counter electrode 5 is preferably a conductive polymer or an inorganic transparent conductor. The conductive polymer is, for example, polyaniline,
Polythiophene, polypyrrole, polythienylene, polyfuran, polyselenophene, polyphenylene, poly N-
Vinyl carbazole and the like, and their derivatives are preferred.

As the material of the inorganic transparent conductive film, in the case of a metal oxide semiconductor, an oxide of a transition metal, for example, titanium, zirconium, hafnium, strontium, zinc, tin, indium, yttrium, lanthanum, vanadium, niobium, tantalum, chromium, Molybdenum, oxide of tungsten, SrTiO ₃ , CaTiO ₃ , BaTiO ₃ , M
gTiO _3, perovskite such as SrNb ₂ O _6,
Alternatively, these composite oxides or oxide mixtures, Ga
N and the like are preferable.

The EC material is characterized by causing a color change by an oxidation-reduction reaction, and includes a phthalocyanine dye, a naphthalocyanine dye, a porphyrin dye, a perylene dye, an anthraquinone dye, an azo dye, a quinophthalone dye, a naphthoquinone dye, and a cyanine dye. Dyes, low molecular weight dyes such as merocyanine dyes, and derivatives or mixtures thereof, polyaniline, polythiophene, polypyrrole, polythienylene, polyfuran, polyselenophene,
Polymers such as polyphenylene, poly N-vinyl carbazole, and derivatives or mixtures thereof are preferred.

The electrolyte layer 4 contains ions in a solvent. When the electrochromic display element is driven, the counter electrode 5
Ions move in the solvent between the C material layer 3 and transfer charges. A solid electrolyte in which the solvent portion is solidified is also used.

The ion is composed of a single atom such as lithium ion or hydrogen ion, or a plurality of atoms such as sulfate ion, ammonium ion, perchlorate ion, tetrafluoroborate ion and hexafluorophosphate ion. Ions are preferred, and those that are not easily redox themselves are preferred. Further, as the solvent, an inorganic or organic liquid such as water, various alcohols, acetonitrile, ethylene carbonate and propylene carbonate is used.

As the solid electrolyte, for example, polyethylene oxide, acetonitrile, ethylene carbonate, propylene carbonate or a mixture thereof can be used.
Alternatively, polyacrylonitrile, polyvinylidene fluoride, polyvinyl alcohol, polyacrylic acid, gel electrolyte mixed and polymerized with a host polymer such as polyacrylamide, polyethylene oxide, polyethylene oxide or sulfonimide salt on the polymer side chain such as polyethylene or polyethylene. Solid electrolytes having salts such as alkyl imidazolium salts, tetracyanoquinodimethane salts, and dicyanoquinodiimine salts are preferably used.

Incidentally, a light scattering layer may be included in the electrolyte layer 4 in order to increase the contrast of the display color. The light scattering layer has a function of covering the portion from the EC material portion where the color change occurs, and increasing the color contrast by scattering or reflecting light, and furthermore, the ions in the electrolyte layer 4 are transferred from the counter electrode 5 to the EC material portion. It is necessary to have ion conductivity so that it can move to the layer 3. The material of the light scattering layer is desirably a fine particle of a metal oxide such as TiO ₂ or Al ₂ O ₃ having a fine particle size of 300 nm or more and a strong light scattering property, or a porous material of an insulating polymer.

Further, in order to prevent a short circuit due to the contact between the counter electrode 5 and the EC material layer 3, a spacer such as a polymer bead, a glass ball, a glass tube or the like may be provided in the electrolyte layer 4.
A third embodiment corresponding to the third embodiment will be described below.

[0072]

Embodiment 3 On a glass substrate having a thickness of 0.1 mm, a thickness of 0.1 mm is applied.
A 50-nm-thick polythiophene film was formed as an EC material layer on a transparent electrode formed with a 1-μm ITO film by an electrolytic polymerization method. Electrolytic polymerization is performed using 0.1 M
Acetonitrile containing LiClO ₄ and 0.1 M of a thiophene monomer were used, and the polymerization voltage was 1.0 V vs. SCE.

Around the obtained ITO glass substrate with a polymer film, an epoxy sealant containing glass beads having a diameter of 2.0 μm was applied as a spacer, and ITO having a thickness of 0.1 mm was provided as a counter electrode. A glass substrate was bonded. At the time of laminating, the sealant was not applied to the entire periphery, but two electrolyte inlets were provided. Thereby, an ITO glass substrate, an EC material layer having a thickness of 50 nm, 1 μm
A space having a thickness of m and an opposite IT0 glass substrate were obtained.

Subsequently, a 1: 1 mixture of ethylene carbonate and propylene carbonate containing 0.1 M LiClO ₄ as an electrolyte was injected into the space from one of the electrolyte filling ports. After the injection of the electrolyte, the opening for filling the electrolyte was sealed with an epoxy sealant to obtain an EC display unit layer.

The obtained EC display unit layer has a thickness of 0.1 m.
m glass substrate with ITO, 50 nm thick EC material layer,
It is composed of a 1 μm thick electrolyte layer, a glass substrate with a counter-ITO with a thickness of 0.1 mm, a thickness of approximately 0.2 mm,
The periphery is hardened with epoxy resin.

FIG. 4 shows the coloring characteristics of the EC display unit layer. In a saturated state in which all the EC materials are colored, the light absorptivity of visible light is 30%, and a very dark color cannot be obtained with one EC display unit layer. The time required for color development was 10 msec until the light absorption rate reached 20%, but it took 100 msec until the light absorption rate reached 30% in the saturated state.

Next, when five EC display unit layers are stacked to form a laminated electrochromic display element, FIG.
As shown in FIG.
% Light absorption rate, and takes 100 msec., But reaches 10% until the light absorption rate reaches 70%, and both color development and decoloration are extremely fast. Therefore, this multilayer electrochromic display element can be used with a light absorption rate of 70% as a colored state and a response speed of 10 msec.

[0078]

Comparative Example 2 The same procedure as in Example 3 was performed, except that a 5 μm-thick polythiophene film, 10 μm-diameter glass beads, and a 5 μm-thick electrolyte layer were provided as an EC material layer. A single-layer type electrochromic display device was obtained.

When the coloring properties of the obtained electrochromic display element were examined, the light absorption in a saturated state where all the EC materials developed reached 85%, and the five-layered electrochromic display of Example 3 was used. It has the same value as that of the device, but it took 10 seconds to reach a saturation state of 85% and 1 second to a light absorption rate of 70%.

[0080]

Embodiment 4 The fabrication method is the same as that of Embodiment 3 described above, except that the thickness of the EC material layer is 0.2 μm and 0.4 μm, respectively.
Four EC display unit layers of m, 0.8 μm, and 1.6 μm were laminated to obtain an intermediate color type electrochromic display device. A drive electrode is connected to the transparent electrode of each EC display unit layer, and the ON / OFF drive control of each EC display unit layer is selectively performed.
% Can be adjusted in 15 steps, and the response speed is 10 msec.
Was obtained.

[0081]

Fifth Embodiment In the same manner as in the above-described fourth embodiment, as the EC material, a yellow EC material, a cyan EC material, and a magenta EC material of a thiophene derivative exhibiting transparent → yellow, transparent → cyan, and transparent → magenta, respectively. By laminating three high-speed intermediate color EC display unit layers using, a high-speed full-color electrochromic display device having a response speed of 10 msec was obtained.

Next, an electrochromic display device according to a fourth embodiment of the present invention will be described. According to the present embodiment, the electrochromic display element
As shown in FIGS. 6 to 8, the EC display unit layer is formed by winding a plurality of turns around the transparent support, and has a roll structure.

As an EC display unit layer to be wound, an EC as shown in FIG.
It is preferable that the display sheet 20 is manufactured by a method of rolling around a transparent support 24 having a rectangular plate shape, for example.

The EC display sheet 20 includes a transparent sheet 22 functioning as a transparent substrate, transparent electrodes 2 and 5 formed on both sides of the transparent sheet, an EC material layer 3 formed on one of the transparent electrodes 2, and the other transparent electrode. It comprises an electrolyte layer 4 provided on an electrode 5.

The transparent sheet 22 is not particularly limited as long as it is a transparent insulator having flexibility.
A polymer sheet such as ET is preferred. This transparent sheet 22
Transparent electrodes 2, 5 provided on the front and back surfaces of
Are a positive electrode and a negative electrode when the electrochromic display element operates.

After winding the EC display sheet 20 around the transparent support 24, the transparent electrodes 2, 5 are provided on the left and right sides of the front and back surfaces of the transparent sheet 22 in order to take out the electric wires from the positive electrode and the negative electrode, respectively. Have been.

That is, the EC display sheet 20 shown in FIG.
In the above, the transparent electrode 2 formed on the surface of the transparent sheet 22 is provided so as to be exposed only on one side edge of the transparent sheet 22, and the transparent electrode 5 on the back surface of the transparent sheet 22 is provided on the other side edge of the transparent sheet 22. Only exposed to.

For this reason, in a state where the EC display sheet 20 is wound on the transparent support 24 as shown in FIGS. 6 and 7, a positive electrode is provided on one end surface in the axial direction of the formed roll-shaped electrochromic display element. The negative electrode is independently exposed from the other end face. By forming the transparent electrodes 2 and 5 on the front and back surfaces of the transparent sheet 22 so as to be shifted in opposite directions along the axis of the roll, both electrodes can be easily taken out from the rolled cell.

The edge of the transparent electrode 2 exposed at one end in the axial direction of the roll-shaped electrochromic display element and the edge of the transparent electrode 5 exposed at the other end are:
Electrode plates 28 and 30 are attached by conductive paste 26, respectively.

As described above, the EC display sheet 20 is wound around the transparent support 22 a plurality of times to form a roll, so that a plurality of EC display sheets are laminated along the display direction to form a roll-shaped and laminated electro-optical device. A chromic display element is obtained.

The EC provided on the transparent electrodes 2 and 5
The material layer 3 and the electrolyte layer 4 may be pre-applied before the roll process, or, as shown in FIG.
For example, the electrolyte material 21 may be applied during the roll process of the EC display sheet 20. The EC material layer 3 and the electrolyte layer 4 are solid at room temperature, but preferably have the property of being liquid at the melting point or higher. It is desirable to apply each of the materials described above at a temperature higher than the melting point of the material and under reduced pressure vacuum so that the material can be well bonded to the transparent sheet surface.

Next, an example corresponding to the fourth embodiment will be described.

[0093]

Embodiment 6 First, as shown in FIG.
2, ITO is deposited as a transparent conductive material from obliquely upper right and lower left. At this time, barriers 30 and 31 are provided along both side edges of the transparent sheet 22 so that each transparent conductive material does not wrap around to the opposite surface of the transparent sheet 22.
Is provided.

An EC material layer 3 is provided on one of the transparent electrodes 2 among the transparent electrodes formed on both sides of the transparent sheet 22. The EC material layer 3 was formed on the transparent electrode 2 as a thin film having a thickness of 0.1 μm by using polythiophene by electrolytic polymerization.

Subsequently, the sheet with an EC material layer obtained as described above was wound around a transparent support plate 24. that time,
Similarly to FIG. 9, the solid electrolyte material 9 was applied between the windings of the sheet with the EC material layer to form the electrolyte layer 4.

Although the solid electrolyte material is solid at room temperature,
Becomes liquid above the melting point. The application of the solid electrolyte material was performed at 100 ° C. or higher, which is equal to or higher than the melting point of the solid electrolyte material, so that the solid electrolyte material can be bonded well. When the solid electrolyte material is applied, the thickness of the electrolyte layer is suppressed to 0.1 μm and
In order to prevent an electrical short circuit between the C material layer 3 and the transparent electrode 5, a glass spacer having a radius of 0.1 μm was included in the electrolyte material. The sheet with the EC layer was wound 10 times around the transparent support plate 22 by the above-described roll process.

Subsequently, the electrodes were taken out of the roll-type laminated electrochromic display element prepared as described above. That is, similarly to FIG. 6, a conductive paste was applied to the transparent electrodes 2 and 5 exposed on both end surfaces of the roll, and the electrode plates 28 and 30 were attached respectively.

The obtained roll type laminated electrochromic display element has a saturated color light absorption of 80%, a time required for saturated color development of 10 msec, and a time required for reaching a light absorption rate of 70% of 1 msec. Met. This laminated electrochromic display element can be used as an ultra-high-speed electrochromic display element having a normal color absorbance of 70% and a response time of 1 msec.

[0099]

As described above, according to the electrochromic display device of the present invention, ions can be arranged at a high concentration in the vicinity of the EC material by using a molten salt electrolyte.
Solves the problem of ion diffusion control in the electrolyte.
Reducing the time required for ions to diffuse from the surface of the EC material to the inside by reducing the thickness of the material layer solves the problem of ion diffusion in the EC material, and furthermore, the electrode or the EC material layer itself has a fine uneven structure. By increasing the effective surface area of the EC material layer, the lack of color density due to the thinning of the EC material layer can be solved. As a result, it is possible to provide an electrochromic display device having a high-speed response and a sufficient color density, and by using this electrochromic display device, it is possible to display moving images and characters which cannot be obtained with a conventional electrochromic device. An electrochromic display capable of displaying can be manufactured.

Further, according to the present invention, by providing at least two EC display unit layers laminated in the display direction, an electrochromic display element capable of high-speed response and obtaining a sufficient color density is provided. Can be provided. Further, according to the present invention, an intermediate color display,
Further, it is possible to provide a high-speed response electrochromic display element capable of full-color display.

Further, according to the present invention, a roll-up structure in which the EC display unit layer is wound around a transparent support can provide a multilayer laminate type electrochromic display element which is easy to manufacture.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an electrochromic display device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing an electrochromic display element according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing a multilayer electrochromic display element according to a third embodiment of the present invention.

FIG. 4 is a graph showing color development characteristics of an EC display unit layer in the multilayer electrochromic display element.

FIG. 5 is a graph showing the color-developing characteristics of the entire stack type electrochromic display element.

FIG. 6 is a perspective view showing a multilayer electrochromic display device having a roll structure according to a fourth embodiment of the present invention.

FIG. 7 is a sectional view taken along the line AA in FIG. 6;

FIG. 8 is a perspective view showing the EC display sheet in the multilayer electrochromic display element having the roll structure, partially cut away.

FIG. 9 is a diagram schematically showing a roll process of an EC display sheet in the multilayer electrochromic display element having the roll structure.

FIG. 10 is a view schematically showing an electrode deposition step on a transparent sheet of the EC display sheet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... 1st transparent substrate 2 ... Transparent electrode 3 ... EC material layer 4 ... Electrolyte layer 5 ... Counter electrode 6 ... 2nd transparent substrate 10 ... EC display unit layer 20 ... EC display sheet 22 ... Transparent sheet 24 ... Transparent support

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2K001 AA01 BB21 BB28 CA08 CA09 CA18 CA22 5C080 AA11 BB09 CC03 DD01 DD08 EE29 EE30 FF09 HH21 JJ04 JJ06 5C094 AA06 AA08 AA13 BA07 BA12 BA53 FB02

Claims (13)

[Claims] The present invention has a fine uneven structure on the surface and a film thickness of 10
An electrochromic material layer having a thickness of 0 nm or less, a molten salt electrolyte layer in contact with the surface of the electrochromic material layer, and first and second electrodes opposed to each other with the electrochromic material layer and the molten salt electrolyte layer interposed therebetween An electrochromic display element comprising: 2. The electrochromic display device according to claim 1, wherein the surface area of the surface of the electrochromic material layer is 50 or more. 3. A first electrode having a fine concavo-convex structure on a surface, an electrochromic material layer provided on the surface of the first electrode and having a thickness of 10 nm or less, and a melt in contact with the electrochromic material layer. An electrochromic display device comprising: a salt electrolyte layer; and a second electrode opposed to the first electrode with the electrochromic material layer and the molten salt electrolyte layer interposed therebetween. 4. The electrochromic display device according to claim 3, wherein the surface area of the surface of the first electrode is 50 or more. 5. The electrochromic display device according to claim 1, wherein the electrochromic material layer contains a functional group that is chemically bonded to the first electrode. . 6. The electrochromic display device according to claim 1, wherein the pitch of the uneven structure is formed to be 100 nm or less. 7. An electrochromic material layer, an electrolyte layer in contact with a surface of the electrochromic material layer, and first and second transparent electrodes opposed to each other with the electrochromic material layer and the electrolyte layer interposed therebetween. Wherein at least two electrochromic display unit layers each having the following structure are laminated in the display direction. 8. The thickness of the electrochromic material layer in the electrochromic display unit layer is 50 nm.
The electrochromic display device according to claim 8, wherein the thickness of each of the electrolyte layers is 1 μm or less, and the distance between the first transparent electrode and the second transparent electrode is 2 μm or less. . 9. The electrochromic display element according to claim 8, wherein a plurality of intermediate colors are expressed by selectively driving each of the plurality of electrochromic display unit layers. 10. The electrochromic display device according to claim 9, wherein the ratio of the coloring densities of the electrochromic material layers in the plurality of electrochromic display unit layers is set to a factor of 2. . 11. The electrochromic display according to claim 9, wherein the electrochromic material layers in the plurality of electrochromic display unit layers are formed of electrochromic materials having different colors from each other. element. 12. An electrochromic material layer, an electrolyte layer in contact with a surface of the electrochromic material layer,
An electrochromic display unit layer having the first and second transparent electrodes opposed to each other with the electrochromic material layer and the electrolyte layer interposed therebetween is wound around the transparent support a plurality of times to form a roll structure. An electrochromic display element, characterized in that: 13. The first transparent electrode is provided to be biased to one side along the axial direction of the roll structure, and has an edge exposed at one axial end of the roll structure. The second transparent electrode is provided to be biased to the other side along the axial direction of the roll structure, and has an edge exposed at the other axial side of the roll structure; The electrochromic display element according to claim 12, wherein the first and second electrode plates are connected to the edge of the electrode and the edge of the second transparent electrode, respectively.