JP7480561B2 - Electrochromic element and manufacturing method thereof, as well as electrochromic photochromic element, electrochromic photochromic lens, and electrochromic device - Google Patents

Description

The present invention relates to an electrochromic element, a method for manufacturing an electrochromic element, an electrochromic photochromic element, an electrochromic photochromic lens, and an electrochromic device.

The phenomenon in which a reversible redox reaction occurs when a voltage is applied, causing a reversible change in color, is called electrochromism. An element that utilizes this electrochromism is an electrochromic element. The electrochromic element is characterized by its high transparency and the ability to achieve a deep color density when colored, and is expected to be used as a light control element.

In addition, by using a resin substrate as the base material, it is possible to create a film-like electrochromic element. This makes it possible to create electrochromic elements that can be bent or have a three-dimensional shape.

One example of a field in which the application of electrochromic elements as described above is particularly promising is photochromic lenses for glasses. Conventional photochromic lenses are generally photochromic lenses that change color when exposed to ultraviolet light (see, for example, Patent Document 1). However, because the color changes with light, there are problems such as the user being unable to adjust the color, the coloring effect being reduced in cars that block ultraviolet light, and long response times.

It is believed that these issues could be overcome if photochromic lenses using electrochromic elements could be realized, and so much research and development has been carried out to date. For example, it has been proposed to form electrochromic elements directly on eyeglass lenses (see, for example, Patent Document 2).

One of the challenges in applying electrochromic elements to eyeglass lenses is productivity. Since the curved shape of eyeglass lenses varies depending on the strength of the wearer's eyes, adjustments to the film-making process are required, which makes stable production difficult. Furthermore, when forming electrochromic elements directly on optical lenses, it is necessary to repeat vacuum film-making and wet coating many times using expensive lenses as substrates, which increases costs when defects occur.

In response to this, an electrochromic element has been proposed in which a flat electrochromic element is formed into a desired curved surface by thermal molding, and one surface of the electrochromic element has an optical lens (see, for example, Patent Document 3). An electrochromic element suitable for such a process is produced by forming an electrochromic material between two opposing electrodes using a resin substrate as a support, and then laminating them together via an ion-conductive electrolyte layer. The electrochromic element is then placed between a concave-convex mold or the like that is heated to a temperature close to the softening point or glass transition temperature of the resin substrate, and thermally molded, making it possible to process it into a curved shape or a three-dimensional shape. As methods for forming lenses, a method of embedding the electrochromic element in molten lens resin and hardening it, and a method of directly laminating the electrochromic element to the lens have been proposed. This method allows for a high degree of freedom in shape, and makes it possible to produce a wide variety of lenses in small quantities at low cost.

The present invention aims to provide an electrochromic element that can prevent phase separation of a gel electrolyte caused by thermoforming.

The electrochromic element of the present invention as a means for solving the above-mentioned problems is an electrochromic element having a laminate having a desired curved shape, which is composed of a resin support, a first electrode layer, an electrochromic layer, and a second electrode layer provided in that order, and which has a gel electrolyte between the first electrode layer and the second electrode layer, the gel electrolyte containing a binder resin, the binder resin containing a urethane resin unit, the phase separation temperature of the gel electrolyte being higher than the softening point of the support, and the difference between the phase separation temperature of the gel electrolyte and the softening point of the support being 10° C. or more .

The present invention provides an electrochromic element that can prevent phase separation of a gel electrolyte caused by thermoforming.

FIG. 1A is a schematic cross-sectional view showing an example of an electrochromic element before thermoforming according to a first embodiment. FIG. 1B is a schematic cross-sectional view showing an example of an electrochromic element after thermoforming according to the first embodiment. FIG. 1C is a schematic cross-sectional view showing an example of an electrochromic element after the optical lens according to the first embodiment is bonded. FIG. 2A is a schematic cross-sectional view showing an example of an electrochromic element before thermoforming according to a first modification of the first embodiment. FIG. 2B is a schematic cross-sectional view showing an example of an electrochromic element after thermoforming according to the first modification of the first embodiment. FIG. 2C is a schematic cross-sectional view showing an example of an electrochromic element after an optical lens according to Modification 1 of the first embodiment is bonded thereto. FIG. 3A is a schematic cross-sectional view showing an example of an electrochromic element before thermoforming according to Modification 2 of the first embodiment. FIG. 3B is a schematic cross-sectional view showing an example of an electrochromic element after thermoforming according to the second modification of the first embodiment. FIG. 3C is a schematic cross-sectional view showing an example of an electrochromic element after an optical lens according to Modification 2 of the first embodiment is bonded thereto. FIG. 4A is a schematic cross-sectional view showing an example of an electrochromic element before thermoforming according to Modification 3 of the first embodiment. FIG. 4B is a schematic cross-sectional view showing an example of an electrochromic element after thermoforming according to the third modification of the first embodiment. FIG. 4C is a schematic cross-sectional view showing an example of an electrochromic element after an optical lens according to Modification 3 of the first embodiment is bonded thereto. FIG. 5 is a schematic cross-sectional view showing an example of an electrochromic element after an optical lens according to the fourth modification of the first embodiment is bonded thereto. FIG. 6 is a schematic cross-sectional view showing an example of an electrochromic element after an optical lens according to a fifth modification of the first embodiment is bonded thereto. FIG. 7 is a perspective view showing an example of electrochromic light control spectacles having the electrochromic light control element of the present invention.

(Electrochromic element)
The electrochromic element of the present invention is an electrochromic element having a laminate including a resin support, a first electrode layer, an electrochromic layer, and a second electrode layer provided in that order, the electrochromic element having a gel electrolyte between the first electrode layer and the second electrode layer, the phase separation temperature of the gel electrolyte being higher than the softening point of the support, and further having other layers as necessary.

In conventional technology, the electrolyte layer used in electrochromic elements has poor heat resistance, and when heat is applied above a certain temperature, the liquid and solid components in the electrolyte layer undergo phase separation, compromising the reliability of the device. There are also problems such as optical distortion and peeling, which impairs the optical quality. Furthermore, to form the desired curved shape by thermoforming, a temperature close to or higher than the softening point of the resin substrate is applied, which can exacerbate these problems. The present invention is based on these findings.

In the present invention, the softening point of the support means the temperature at which the resin constituting the support begins to deform.
The softening point of the support can be determined, for example, by applying heat to the support using a needle probe in a TMA (thermomechanical analysis) device (manufactured by Kobelco Research Institute, Ltd.) and measuring the displacement of the resin that constitutes the support.

Here, the phase separation temperature of the gel electrolyte means the temperature at which the matrix polymer and the liquid are separated. In the present invention, a gel electrolyte is formed, and for example, the state in which the liquid rises to the surface of the gel electrolyte layer when heated is observed, and the temperature is taken as the phase separation temperature. When the electrochromic element is heated at a temperature exceeding the phase separation temperature of the gel electrolyte, the flow of the liquid inside the element becomes active, and the adhesion at the interface between the gel electrolyte and the electrochromic layer, the interface between the gel electrolyte and the electrode, or the interface between the gel electrolyte and the protective layer is reduced, and problems such as optical distortion and peeling may occur. Such problems may occur significantly when the electrochromic element is heated to a temperature close to or higher than the softening point of the resin substrate, so that by increasing the phase separation temperature of the gel electrolyte, such problems can be suppressed and the reliability of the element can be improved.
The phase separation temperature of the gel electrolyte is determined, for example, by placing the gel electrolyte layer on a hot plate, heating the layer, visually observing the membrane surface during the heating process, and measuring the temperature at which liquid is generated on the surface of the gel electrolyte layer. This temperature is regarded as the phase separation temperature.

In an embodiment of the present invention, it is preferable that the laminate has a desired curved shape by thermoforming.
The thermoforming method is a method of hot forming a laminate using a convex mold and a concave mold having a desired 3D shape without fixing the ends of the support. Furthermore, thermoforming and vacuum forming may be combined.

The "desired curved shape" is a shape composed of curved surfaces with curvature, such as a sphere, a cylinder, a cone, or various three-dimensional (3D) shapes. The "desired curved shape" may be at least a part of the laminate, or it may be the entire laminate.

In the thermoforming process, it is preferable to heat the support to a temperature close to or higher than the softening point of the material that constitutes the support. In this case, it has been found that by setting the phase separation temperature of the gel electrolyte higher than the softening point of the support material, it is possible to solve the problem of phase separation of the gel electrolyte in the thermoforming process.

The gel electrolyte in the embodiment of the present invention contains a binder resin described below, and it is preferable that the binder resin contains a urethane resin unit. By containing a urethane resin unit, it is possible to dramatically increase the phase separation temperature of the gel electrolyte. In addition, it is possible to provide the physical properties required for a gel electrolyte, such as improving the strength of the membrane.

The gel electrolyte in the embodiment of the present invention contains a binder resin described below, and it is preferable that the binder resin contains at least one selected from a polyethylene oxide (PEO) chain and a polymethyl methacrylate (PMMA) chain. This makes it possible to increase compatibility with the liquid electrolyte, and to increase the phase separation temperature. It is also possible to increase the phase separation temperature by using it in combination with a urethane resin unit.

In an embodiment of the present invention, the solid content of the gel electrolyte is preferably 50% by mass or less, and more preferably 40% by mass or less. When the solid content of the gel electrolyte is 50% by mass or less, it is possible to sufficiently increase the ionic conductivity and shorten the response time of the electrochromic element. The lower limit of the solid content of the gel electrolyte is about 10% by mass in terms of the phase separation temperature.

The gel electrolyte in the embodiment of the present invention preferably contains an ionic liquid. Ionic liquid is stable over a wide temperature range and is a non-volatile and chemically stable material, thereby improving the reliability of the electrochromic element. Furthermore, by mixing with a urethane resin unit, it is possible to obtain a gel electrolyte that has a high phase separation temperature and is thermally stable. Furthermore, by mixing with a resin that contains a polyethylene oxide (PEO) chain or a polymethyl methacrylate (PMMA) chain, it is possible to obtain a gel electrolyte that has a high phase separation temperature and is thermally stable.

The phase separation temperature of the gel electrolyte is preferably 160°C or higher, and more preferably 200°C or higher. If the phase separation temperature of the gel electrolyte is 160°C or higher, the temperature during thermal molding can be increased, which allows for greater freedom in the selection of the substrate material. The upper limit of the phase separation temperature of the gel electrolyte is approximately 250°C, from the standpoint of the heat resistance of the electrochromic layer, etc.

The softening point of the support is preferably 200°C or less, and more preferably 160°C or less. This makes it possible to suppress thermal deterioration of the electrochromic material and gel electrolyte binder contained in the electrochromic element. The lower limit of the softening point of the support is about 100°C from the viewpoint of practical stability, including the storage environment.

The difference between the phase separation temperature of the gel electrolyte and the softening point of the support is preferably 10°C or more, more preferably 20°C or more. If the difference between the phase separation temperature of the gel electrolyte and the softening point of the support is 50°C or more, the degree of reproduction of the mold by thermoforming can be improved. The upper limit of the difference between the phase separation temperature of the gel electrolyte and the softening point of the support is about 80°C, from the viewpoints of the freedom of material selection for the support and the suppression of deterioration of the electrochromic material.

In the electrochromic element, the support is preferably a resin substrate. Since a desired curved shape is formed by thermoforming a laminate in which each layer is formed on the planar resin substrate, an electrochromic element having excellent productivity in forming a coating film can be provided.
The support preferably contains at least one resin selected from the group consisting of polycarbonate resin, polyethylene terephthalate resin, polymethyl methacrylate resin, urethane resin, polyolefin resin, and polyvinyl alcohol resin. Among these, polycarbonate resin, polyethylene terephthalate resin, and polymethyl methacrylate resin are preferred from the viewpoints of moldability and film formability of the coating film.

When the gel electrolyte becomes a layered gel electrolyte layer, the thickness is preferably between 30 μm and 150 μm. When the thickness of the gel electrolyte layer is within this range, degradation of optical quality due to unevenness in film thickness during hardening and shrinkage of the gel electrolyte layer is unlikely to occur, and the problem of high material costs for the gel electrolyte layer is unlikely to occur. In addition, short circuits between the electrodes of the electrochromic element are unlikely to occur, improving reliability.

In the present invention, it is preferable that the laminate has an optical lens on at least one surface. This makes it possible to provide an electrochromic element that has high mechanical strength, a desired curved shape by thermoforming, and is suitable for optical applications such as lenses.

The optical lens may not only be formed on one surface of the laminate, but also be formed so as to embed the laminate.
The optical lens preferably contains at least one transparent material selected from polycarbonate resin, allyl diglycol carbonate resin, diallyl carbonate resin, diallyl phthalate resin, urethane resin, thiourethane resin, episulfide resin, (meth)acrylate resin, and cycloolefin resin. Among these, polycarbonate resin, thiourethane resin, and allyl diglycol carbonate resin are preferred from the viewpoint of mechanical strength.

The transparent material can be brought into contact with one surface of the laminate and then melted and re-hardened, or hardened by applying light or heat, to form an optical lens. The laminate and the optical lens can also be bonded together via an adhesive layer.

The material of the adhesive layer is not particularly limited and can be appropriately selected depending on the purpose. Examples include transparent materials such as epoxy resins, urethane resins, acrylic resins, and vinyl acetate resins. Among these, acrylic resins are preferred.

It is preferable from the viewpoint of scratch resistance that the other surface of the laminate be the support.
The electrochromic element has at least one support, and may have one support or two supports. When the electrochromic element is composed of one support, the effect of reducing material costs can be obtained.

(Method of manufacturing electrochromic element)
The method for producing an electrochromic element of the present invention is a method for producing the electrochromic element of the present invention, and includes a step of thermoforming the produced laminate so that it has a desired curved shape, and a step of bonding an optical lens to the laminate, and further includes other steps as necessary.

As the thermoforming, a method of heat-forming the laminate using a convex mold and a concave mold having a desired 3D shape without fixing the ends of the support is suitable.
The heating temperature in the thermoforming is preferably equal to or higher than the softening point of the material constituting the support. For example, when a polycarbonate resin is used as the support, the heating temperature is more preferably 130° C. or higher and 190° C. or lower.

In the process of adhering an optical lens to the laminate, the transparent material of the optical lens is brought into contact with one surface of the laminate, and then melted and re-hardened, or hardened by applying light or heat, to form the optical lens. The laminate and the optical lens can also be adhered via an adhesive layer.

In the manufacturing method of the electrochromic element, it is preferable that the optical lens adhered to the outer surface of the support has a temporary power and a temporary thickness. By cutting the optical lens after adhesion, the desired curved shape can be formed, making it possible to precisely process the lens (power processing, etc.) according to the specific conditions of the user. In other words, it is no longer necessary to prepare molds and parts for each product shape, making it easier to produce a wide variety of products in small quantities.

Here, the embodiment will be described with reference to the drawings. Note that in each drawing, the same components are given the same reference numerals, and duplicated descriptions may be omitted.

<Electrochromic element according to the first embodiment and its manufacturing method>
1A, 1B, and 1C are schematic cross-sectional views showing an example of an electrochromic element 10 according to a first embodiment. Fig. 1A shows the electrochromic element 10 before thermoforming, Fig. 1B shows the electrochromic element 10 after thermoforming, and Fig. 1C shows the electrochromic element 10 after lens bonding. Referring to Fig. 1A, 1B, and 1C, the electrochromic element 10 includes a first support 11, a first electrode layer 12 and an electrochromic layer 13, which are sequentially laminated on the first support 11, and a second support 16, a second electrode layer 15, a gel electrolyte layer 14, which is formed between the opposing electrodes, and a protective layer 17, which seals the outer periphery of the electrochromic element 10.

In the electrochromic element 10, a first electrode layer 12 is provided on a first support 11, and an electrochromic layer 13 is provided in contact with the first electrode layer 12. A second electrode layer 15 is provided on the electrochromic layer 13 so as to face the first electrode layer 12 with a gel electrolyte layer 14 interposed therebetween.
For convenience, the mutually opposing surfaces of the first electrode layer 12 and the second electrode layer 15 are referred to as the inner surfaces, and the surfaces opposite the inner surfaces are referred to as the outer surfaces. In this embodiment, the inner surface of the first electrode layer 12 is in contact with the electrochromic layer 13, and the outer surface of the first electrode layer 12 is in contact with the first support 11. The inner surface of the second electrode layer 15 is in contact with the gel electrolyte layer 14, and the outer surface of the second electrode layer 15 is in contact with the second support 16. In Figures 1A, 1B, and 1C, 17 is a protective layer, and 21 is an optical lens.

The manufacturing method of the electrochromic element 10 of the first embodiment includes a step of sequentially laminating a first electrode layer 12 and an electrochromic layer 13 on a first support 11, a step of forming a second electrode layer 15 on a second support 16, a step of forming a gel electrolyte layer 14 between the two supports, curing the gel electrolyte layer 14, and further sealing the outer periphery with a protective layer 17. Thereafter, a step of forming a curved shape by thermoforming. The method may further include other steps as necessary.
The manufacturing method of the electrochromic element 10 of the first embodiment includes a step of sequentially laminating the first electrode layer 12 and the electrochromic layer 13 on the first support 11, a step of forming a gel electrolyte layer 14 on the electrochromic layer 13, curing the gel electrolyte layer 14, and laminating the second electrode layer 15, a step of forming a second support 16 made of a cured resin on the second electrode layer 15, a step of sealing the outer periphery with a protective layer 17, and a step of forming a curved shape by thermoforming, and further includes other steps as necessary.
Although FIG. 1B shows a diagram in which the support on the electrochromic layer 13 side is processed into a convex spherical shape, it can also be processed into a concave spherical shape in the same manner.

In the electrochromic element 10, when a voltage is applied between the first electrode layer 12 and the second electrode layer 15, the electrochromic layer 13 undergoes an oxidation-reduction reaction due to the transfer of electric charges, and develops or fades color.
In this manner, in the electrochromic element according to the first embodiment, a curved surface of a desired 3D shape can be formed by thermoforming, so that an electrochromic element with excellent productivity (large size) can be provided.
Furthermore, the electrochromic element according to the first embodiment can realize an electrochromic element with excellent color characteristics by using an organic electrochromic material.

The following describes in detail each of the components that make up the electrochromic element 10 according to the first embodiment.

[Support]
The first and second supports 11 and 16 have the function of supporting the first electrode layer 12 , the electrochromic layer 13 , the gel electrolyte layer 14 , the second electrode layer 15 , and the protective layer 17 .
As the first and second supports 11 and 16, any known thermoformable resin material can be used as is, so long as it can support these layers.
The first and second supports 11 and 16 may be made of a resin substrate such as a polycarbonate resin, a polyethylene terephthalate resin, a polymethyl methacrylate resin, a urethane resin, a polyolefin resin, or a polyvinyl alcohol resin.
When the electrochromic element 10 is a reflective display element that is viewed from the second electrode layer 15 side, it is not necessary for either the first or second support 11, 16 to be transparent. Furthermore, the surfaces of the first and second support 11, 16 may be coated with a transparent insulating layer, an anti-reflection layer, or the like in order to improve the water vapor barrier property, the gas barrier property, and visibility.
The average thickness of the first and second supports 11 and 16 is preferably 0.2 mm or more and 1.0 mm or less in terms of facilitating thermoforming.

[First Electrode Layer, Second Electrode Layer]
As the material of the first electrode layer 12 and the second electrode layer 15, a transparent conductive oxide material is suitable, for example, tin-doped indium oxide (hereinafter referred to as "ITO"), fluorine-doped tin oxide (hereinafter referred to as "FTO"), antimony-doped tin oxide (hereinafter referred to as "ATO"), etc. Among these, an inorganic material containing any one of indium oxide (hereinafter referred to as "In oxide"), tin oxide (hereinafter referred to as "Sn oxide"), and zinc oxide (hereinafter referred to as "Zn oxide") formed by vacuum film formation is preferable.

The In oxide, Sn oxide, and Zn oxide are materials that can be easily formed into a film by a sputtering method, and also have good transparency and electrical conductivity. Among these, InSnO, GaZnO, SnO, In ₂ O ₃ , ZnO, and InZnO are particularly preferred. Furthermore, the lower the crystallinity of the electrode layer, the more preferred it is. This is because the electrode layer is more likely to be divided by thermoforming when the crystallinity is high. From this point of view, IZO and AZO, which show high conductivity in an amorphous film, are preferred. When using these electrode layer materials, it is preferable to thermoform the laminate so that the maximum long axis length of the support on the curved surface of the laminate after thermoforming is 120% or less, and more preferably 103% or less, of the maximum long axis length of the support on the plane of the laminate before thermoforming.

Also useful are transparent conductive metal thin films containing silver, gold, copper, or aluminum, carbon films such as carbon nanotubes and graphene, and further, network electrodes of conductive metals, conductive carbon, conductive oxides, or composite layers thereof. The network electrodes are electrodes that are provided with transmittance by forming carbon nanotubes or other highly conductive non-transparent materials into a fine network. The network electrodes are preferable because they are less likely to break during thermoforming.
Furthermore, it is more preferable that the electrode layer is a laminated structure of a network electrode and the conductive oxide, or a laminated structure of the conductive metal thin film and the conductive oxide. By using a laminated structure, the electrochromic layer can be uniformly colored and faded. The conductive oxide layer can also be formed by coating as a nanoparticle ink. The laminated structure of the conductive metal thin film and the conductive oxide is specifically an electrode that has both conductivity and transparency in a thin film laminated structure such as ITO/Ag/ITO.

The thickness of each of the first electrode layer 12 and the second electrode layer 15 is adjusted so as to obtain an electrical resistance value necessary for the oxidation-reduction reaction of the electrochromic layer 13 .
When vacuum-formed ITO is used as the material for the first electrode layer 12 and the second electrode layer 15, the thickness of each of the first electrode layer 12 and the second electrode layer 15 is preferably 20 nm or more and 500 nm or less, and more preferably 50 nm or more and 200 nm or less.
The conductive oxide layer preferably has a thickness of 0.2 μm to 5 μm when formed by coating a nanoparticle ink, and preferably has a thickness of 0.2 μm to 5 μm when formed as a network electrode.
Furthermore, when used as a switchable mirror, either the first electrode layer 12 or the second electrode layer 15 may have a reflective function. In that case, a metal material may be included as the material of the first electrode layer 12 and the second electrode layer 15. Examples of the metal material include Pt, Ag, Au, Cr, rhodium, Al, alloys thereof, and laminated structures thereof.

Methods for producing the first electrode layer 12 and the second electrode layer 15 include, for example, vacuum deposition, sputtering, and ion plating. In addition, as long as the materials for the first electrode layer 12 and the second electrode layer 15 can be applied, various printing methods such as spin coating, casting, microgravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, slit coating, capillary coating, spray coating, nozzle coating, gravure printing, screen printing, flexographic printing, offset printing, reverse printing, and inkjet printing can be used.

[Electrochromic Layer]
The electrochromic layer 13 is a layer containing an electrochromic material.
The electrochromic material may be either an inorganic electrochromic compound or an organic electrochromic compound, or a conductive polymer known to exhibit electrochromism.
Examples of the inorganic electrochromic compound include tungsten oxide, molybdenum oxide, iridium oxide, and titanium oxide.
Examples of the organic electrochromic compound include viologen, rare earth phthalocyanine, and styryl.
Examples of the conductive polymer include polypyrrole, polythiophene, polyaniline, and derivatives thereof.

As the electrochromic layer 13, it is preferable to use a structure in which an organic electrochromic compound is supported on conductive or semiconductive fine particles. Specifically, the structure is such that fine particles having a particle size of 5 nm to 50 nm are attached to the surface of the electrode layer, and an organic electrochromic compound having a polar group such as phosphonic acid, a carboxyl group, or a silanol group is adsorbed on the surface of the fine particles.

The above structure utilizes the large surface effect of the fine particles to efficiently inject electrons into the organic electrochromic compound, enabling a faster response than conventional electrochromic display elements. Furthermore, the use of fine particles allows a transparent film to be formed as a display layer, making it possible to obtain a high color density of the electrochromic compound. In addition, multiple types of organic electrochromic compounds can be supported on conductive or semiconductive fine particles. Furthermore, the conductive particles can also serve as the conductive electrode layer.
Specifically, examples of the polymer-based and dye-based electrochromic compounds include low molecular weight organic electrochromic compounds such as azobenzene-based, anthraquinone-based, diarylethene-based, dihydroprene-based, dipyridine-based, styryl-based, styrylspiropyran-based, spirooxazine-based, spirothiopyran-based, thioindigo-based, tetrathiafulvalene-based, terephthalic acid-based, triphenylmethane-based, benzidine-based, triphenylamine-based, naphthopyran-based, viologen-based, pyrazoline-based, phenazine-based, phenylenediamine-based, phenoxazine-based, phenothiazine-based, phthalocyanine-based, fluoran-based, fulgide-based, benzopyran-based, and metallocene-based compounds, and conductive polymer compounds such as polyaniline and polythiophene. These may be used alone or in combination of two or more.

Among these, viologen compounds and dipyridine compounds are preferred because they have a low color development/discoloration potential and good color values. For example, dipyridine compounds represented by the following general formula (1) are more preferred.

ただし、前記一般式（１）において、Ｒ１及びＲ２は、それぞれ独立に置換基を有していてもよい炭素数１～８のアルキル基、及びアリール基のいずれかを表し、Ｒ１及びＲ２の少なくとも一方は、ＣＯＯＨ、ＰＯ（ＯＨ）_２、及びＳｉ（ＯＣ_ｋＨ_２ｋ＋１）_３（ただし、ｋは、１～２０を表す）から選択される置換基を有する。 [General formula (1)]

In the general formula (1), R1 and R2 each independently represent either an alkyl group having 1 to 8 carbon atoms, which may have a substituent, or an aryl group, and at least one of R1 and R2 has a substituent selected from COOH, PO(OH) ₂ , and Si(OC _k H _2k+1 ) ₃ (wherein k is 1 to 20).

In the general formula (1), X represents a monovalent anion. The monovalent anion is not particularly limited as long as it stably pairs with the cation moiety and can be appropriately selected depending on the purpose. Examples of the monovalent anion include Br ion (Br ⁻ ), Cl ion (Cl ⁻ ), ClO ₄ ion (ClO ₄ ⁻ ), PF ₆ ion (PF ₆ ⁻ ), and BF ₄ ion (BF ₄ ⁻ ).
In the general formula (1), n, m, and l each independently represent 0, 1, or 2.
In the general formula (1), A, B, and C each independently represent any one of an alkyl group, an aryl group, and a heterocyclic group having 1 to 20 carbon atoms, which may have a substituent.

As the metal complex and metal oxide electrochromic compounds, for example, inorganic electrochromic compounds such as titanium oxide, vanadium oxide, tungsten oxide, indium oxide, iridium oxide, nickel oxide, and Prussian blue can be used.
The conductive or semiconductive fine particles that support the electrochromic compound are not particularly limited and can be appropriately selected depending on the purpose, but it is preferable to use a metal oxide.
Examples of the metal oxide material include metal oxides mainly composed of titanium oxide, zinc oxide, tin oxide, zirconium oxide, cerium oxide, yttrium oxide, boron oxide, magnesium oxide, strontium titanate, potassium titanate, barium titanate, calcium titanate, calcium oxide, ferrite, hafnium oxide, tungsten oxide, iron oxide, copper oxide, nickel oxide, cobalt oxide, barium oxide, strontium oxide, vanadium oxide, aluminosilicate, calcium phosphate, aluminosilicate, etc. These may be used alone or in combination of two or more.
Among these, from the viewpoints of electrical properties such as electrical conductivity and physical properties such as optical properties, at least one selected from titanium oxide, zinc oxide, tin oxide, zirconium oxide, iron oxide, magnesium oxide, indium oxide, and tungsten oxide is preferred, and titanium oxide or tin oxide is particularly preferred from the viewpoints of enabling color display with an excellent response speed in color development and fading.

The shape of the conductive or semiconductive fine particles is not particularly limited and can be appropriately selected depending on the purpose. In order to efficiently support the electrochromic compound, a shape with a large surface area per unit volume (hereinafter referred to as specific surface area) is used. For example, when the fine particles are an aggregate of nanoparticles, the large specific surface area allows the electrochromic compound to be supported more efficiently, resulting in an excellent display contrast ratio for color development and fading.

The electrochromic layer 13 and the conductive or semiconductive particle layer can be formed by vacuum film formation, but from the viewpoint of productivity, it is preferable to form them by coating in the form of a particle-dispersed paste.
The average thickness of the electrochromic layer 13 is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.2 μm or more and 5.0 μm or less. When the average thickness is 0.2 μm or more and 5.0 μm or less, excellent color density is obtained and visibility is not deteriorated by coloring, which is favorable.

[Gel electrolyte layer]
The gel electrolyte layer is made of a binder resin and an electrolyte.

The binder resin is not particularly limited and can be appropriately selected depending on the purpose, but it is preferable that the binder resin contains a urethane resin unit in terms of the phase separation temperature and film strength as a polymer membrane. Furthermore, by containing a polyethylene oxide (PEO) chain, compatibility with the electrolyte is improved and the phase separation temperature can be increased. Furthermore, by containing a polymethyl methacrylate (PMMA) chain, compatibility with the electrolyte is improved and the phase separation temperature can be increased, similar to the case of containing a PEO chain.

The gel electrolyte layer is not particularly limited and can be selected appropriately depending on the purpose, but a liquid electrolyte such as an ionic liquid or a solution in which a solid electrolyte is dissolved in a solvent is used.

The ionic liquid is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include those that are in a liquid state around the temperature of use. Note that the ionic liquid refers to a liquid in which a salt is dissolved and which is in a liquid state at room temperature.
The ionic liquid contains a cation and an anion.

Examples of the cation include imidazole derivatives such as N,N-dimethylimidazole salt, N,N-methylethylimidazole salt, N,N-methylpropylimidazole salt, N,N-methylbutylimidazole salt, and N,N-allylbutylimidazole salt; pyridinium derivatives such as N,N-dimethylpyridinium salt and N,N-methylpropylpyridinium salt; pyrrolidinium derivatives such as N,N-dimethylpyrrolidinium salt, N-ethyl-N-methylpyrrolidinium salt, N-methyl-N-propylpyrrolidinium salt, N-butyl-N-methylpyrrolidinium salt, N-methyl-N-pentylpyrrolidinium salt, and N-hexyl-N-methylpyrrolidinium salt; and cations derived from aliphatic quaternary ammonium salts such as trimethylpropylammonium salt, trimethylhexylammonium salt, and triethylhexylammonium salt. These may be used alone or in combination of two or more.

Examples of the anion include a chlorine anion, a bromine anion, an iodine anion, BF ₄ ^- , BF ₃ CF ₃ ^- , BF ₃ C ₂ F ₅ ^- , PF ₆ ^- , NO ₃ ^- , CF ₃ CO ₂ ^- , CF ₃ SO ₃ ^- , (CF ₃ SO ₂ ) ₂ N ^- , (FSO ₂ ) ₂ N ^- , (CF ₃ SO ₂ ) (FSO ₂ ) N ^- , (CN) ₂ N ^- , (CN) ₃ C ^- , (CN) ₄ B ^- , (CF ₃ SO ₂ ) ₃ C ^- , (C ₂ F ₅ SO ₂ ) ₂ N ^- , and (C ₂ F ₅ ) ₃ PF ₃ ^- , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ and the like. These may be used alone or in combination of two or more.

Examples of the ionic liquid include ethylmethylimidazolium tetracyanoborate (EMIMTCB, manufactured by Merck), ethylmethylimidazolium bistrifluoromethanesulfonimide (EMIMTFSI, manufactured by Kanto Chemical Co., Ltd.), ethylmethylimidazolium tripentafluoroethyl trifluorophosphate (EMIMFAP, manufactured by Merck), allylbutylimidazolium tetrafluoroborate (ABIMBF4, manufactured by Kanto Chemical Co., Ltd.), methylpropylpyrrolidinium bisfluorosulfonimide (P13FSI,
and the like. These may be used alone or in combination of two or more.
The content of the ionic liquid is preferably 50% by mass or more, particularly preferably 80% by mass or more, based on the total amount of the gel electrolyte layer. When the content is 50% by mass or more, ionic conductivity can be improved.
Examples of materials that can be used for the solid electrolyte include inorganic ion salts such as alkali metal salts and _alkaline earth metal salts, quaternary ammonium salts, acids, and alkali supporting salts. Specific examples include _LiClO4 , _LiBF4 , _LiAsF6 , LiPF6, _LiCF3SO3 , _LiCF3COO , KCl, _NaClO3 , NaCl, _NaBF4 , NaSCN, _KBF4 , Mg( _ClO4 ) ₂ , and Mg( _BF4 ) _{2 .}

[Method of manufacturing gel electrolyte layer]
The gel electrolyte layer in the present invention can be produced by a polymerization reaction using a cast polymerization method or the like in which a composition solution is first prepared, and then the prepared composition solution is sandwiched between a mold or a film and polymerized.
The composition solution can be prepared by mixing an electrolytic solution in which the ionic liquid or solid electrolyte is mixed with a solvent, a polymerizable material, and, if necessary, the polymerization initiator and other components.
Examples of the polymerizable material include urethane acrylate monomers, acrylate monomers having a PEO chain, and acrylate monomers having a PMMA chain.
The mold may be a glass or resin container, a film with a release agent, etc. An empty cell of an electrochemical device may be used as a mold to fill the composition solution, and polymerization may be carried out directly in the device.
The polymerization reaction is preferably a radical polymerization reaction, more preferably a thermal radical polymerization reaction or a photoradical polymerization reaction. When carrying out the radical polymerization, it is preferable to deoxygenate the composition solution in advance.

Examples of the solvent include propylene carbonate, acetonitrile, γ-butyrolactone, ethylene carbonate, sulfolane, dioxolane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,2-dimethoxyethane, 1,2-ethoxymethoxyethane, polyethylene glycol, alcohols, and mixed solvents thereof.

The polymerization initiator is not particularly limited and can be appropriately selected depending on the purpose. Examples of the polymerization initiator include radical polymerization initiators.
Examples of the radical polymerization initiator include a thermal polymerization initiator, a photopolymerization initiator, etc. These may be used alone or in combination of two or more kinds.

Examples of the thermal polymerization initiator include azo compounds such as 2,2'-azobisisobutyronitrile, dimethyl-2,2'-azobisisobutyrate, 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis[2-(2-imidazolin-2-yl)propane]; and organic peroxides such as 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and di(4-tert-butylcyclohexyl)peroxydicarbonate. These may be used alone or in combination of two or more.

Examples of the photopolymerization initiator include ketal-based photopolymerization initiators such as 2,2-dimethoxy-1,2-diphenylethan-1-one; acetophenone-based photopolymerization initiators such as 1-hydroxycyclohexyl phenyl ketone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 4-phenoxydichloroacetophenone, and 4-(t-butyl)dichloroacetophenone; and benzoin ether-based photopolymerization initiators such as benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, and benzoin isobutyl ether. These may be used alone or in combination of two or more.

The content of the polymerization initiator is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.001 parts by mass or more and 5 parts by mass or less, more preferably 0.01 parts by mass or more and 2 parts by mass or less, and particularly preferably 0.01 parts by mass or more and 1 part by mass or less, relative to 100 parts by mass of the total monomer components.

Other methods for producing the gel electrolyte layer are not limited to the above, and a method can be used in which a pre-polymerized composition solution is applied onto the electrochromic layer and polymerized by ultraviolet light irradiation or heating. In addition, a method can be used in which the supports on which the electrochromic layer has been formed are placed facing each other with a gap of about 5 μm to 150 μm maintained, and the composition solution is filled and then polymerized by ultraviolet light irradiation or heating.

For the sake of convenience, FIG. 1A illustrates each layer as being completely separate, but depending on the composition of the gel electrolyte layer and the manufacturing method, a structure in which the gel electrolyte composition partially permeates the electrochromic layer may be adopted.

[Protective Layer]
The protective layer 17 is formed to physically and chemically protect the side surface of the electrochromic element. The protective layer 17 can be formed, for example, by applying an ultraviolet-curable or thermosetting insulating resin to cover the side surface and/or the top surface, and then curing the resin. It is also preferable to form the protective layer by laminating a cured resin and an inorganic material. By forming a laminated structure with the inorganic material, the barrier properties against oxygen and water are improved.
The inorganic material is preferably a material having high insulating properties, transparency, and durability, and specific examples of the material include oxides or sulfides of silicon, aluminum, titanium, zinc, tin, etc., or mixtures thereof, etc. These films can be easily formed by a vacuum film-forming process such as a sputtering method or a deposition method.
The average thickness of the protective layer 17 is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 5 μm or more and 100 μm or less. Furthermore, the protective layer may be formed after thermoforming.

The electrochromic element of the present invention is not particularly limited and can be selected appropriately depending on the purpose, but it is preferable that it has the following characteristics.

It is preferable that the refractive index n1 of the support, the refractive index n2 of the optical lens, and the refractive index n3 of the adhesive layer satisfy the following formula, n1≦n3≦n2, in terms of reducing reflection at the adhesive interface and therefore transparency.
Alternatively, it is preferable from the viewpoint of reducing reflection at the adhesive interface and thus transparency that the refractive index n1 of the support, the refractive index n2 of the optical lens, and the refractive index n3 of the adhesive layer satisfy the following formula, n2≦n3≦n1.
The refractive index can be measured, for example, by a multi-wavelength Abbe refractometer (DR-M2, manufactured by Atago Co., Ltd.).

From the viewpoint of thermal stability and mechanical stability, it is preferable that the linear expansion coefficient α1 of the support, the linear expansion coefficient α2 of the optical lens, and the linear expansion coefficient α3 of the adhesive layer satisfy the following formula: α1≦α3≦α2.
From the viewpoint of thermal stability and mechanical stability, it is preferable that the linear expansion coefficient α1 of the support, the linear expansion coefficient α2 of the optical lens, and the linear expansion coefficient α3 of the adhesive layer satisfy the following formula: α2≦α3≦α1.
The linear expansion coefficient can be measured, for example, by a thermomechanical analysis (TMA) device (manufactured by Kobelco Research Institute, Ltd.).

It is preferable from the viewpoint of reducing chromatic aberration that the Abbe number v1 of the support and the Abbe number v2 of the optical lens satisfy the following formula: v1≦v2.
The Abbe number can be measured, for example, by a multi-wavelength Abbe refractometer (DR-M2, manufactured by Atago Co., Ltd.).

<Electrochromic element according to the first embodiment>
Here, Fig. 1C is a cross-sectional view illustrating the electrochromic element of the first embodiment after the optical lens is bonded. Referring to Fig. 1C, the optical lens 21 is bonded to one outer surface of the laminate (electrochromic element 10), and the first support 11 is provided on the other outer surface.

The material of the optical lens 21 is not particularly limited and can be appropriately selected depending on the purpose. For example, transparent materials such as polycarbonate resin, allyl diglycol carbonate resin, diallyl carbonate resin, diallyl phthalate resin, urethane resin, thiourethane resin, episulfide resin, methacrylate resin, and cycloolefin resin are preferably used.

The optical lens 21 is adhered by melting the transparent material so that it is in contact with one of the outer surfaces and then re-hardening it, or by hardening it by applying light or heat. However, the method of adhering the optical lens 21 is not limited to these methods.

By setting the radius of curvature after curing while taking into account deformation due to curing shrinkage, etc., and adjusting at least one of the curvatures of the entrance surface and the exit surface of the optical lens 21, it is possible to give the electrochromic element any desired degree.

In addition, after the optical lens 21 is formed, the desired curved shape can be formed by cutting, making it possible to process the lens (such as power processing) according to the specific conditions of the user. In other words, it is no longer necessary to prepare molds and parts for each product shape, making it easier to produce a wide variety of high-precision products in small quantities.

<Electrochromic Element According to Modification 1 of the First Embodiment>
The first modification of the first embodiment illustrates an electrochromic element having a layer structure different from that of the first embodiment. Note that in the first embodiment, the description of the same components as those of the embodiments already described may be omitted.

2A, 2B, and 2C are cross-sectional views illustrating a first modification of the first embodiment.
2A, 2B, and 2C, the electrochromic element 20 of the first embodiment, variant 1, differs from the electrochromic element 10 of the first embodiment (see FIGS. 1A, 1B, and 1C) in that an anti-degradation layer 18 is formed in contact with the gel electrolyte layer 14 and the second electrode layer 15.
In this first modification of the first embodiment, an anti-degradation layer 18 is formed in order to prevent degradation due to electrochemical reaction of the second electrode layer 15. As a result, the electrochromic element according to the first modification of the first embodiment can provide an electrochromic element with superior repeatability in addition to the effects of the first embodiment.

The role of the anti-degradation layer 18 is to reversely react with the electrochromic layer 13, balance the charge, and prevent the second electrode layer 15 from corroding or deteriorating due to an irreversible oxidation-reduction reaction. As a result, the repetitive stability of the electrochromic element 20 is improved. The reverse reaction includes not only the case where the anti-degradation layer undergoes oxidation-reduction, but also the case where the layer acts as a capacitor.

The material of the degradation prevention layer 18 is not particularly limited as long as it is a material that plays a role in preventing corrosion due to irreversible oxidation-reduction reactions of the first electrode layer 12 and the second electrode layer 15, and is appropriately selected depending on the purpose. For example, antimony tin oxide, nickel oxide, titanium oxide, zinc oxide, tin oxide, or conductive or semiconductive metal oxides containing a plurality of these can be used as the material of the degradation prevention layer 18. Furthermore, when coloring of the degradation prevention layer is not a problem, the same material as the electrochromic material can be used.
Among these, when an electrochromic element is produced as an optical element such as a lens that requires transparency, it is preferable to use a highly transparent material for the degradation prevention layer 18. As such a material, it is preferable to use n-type semiconducting oxide fine particles (n-type semiconducting metal oxide). As the n-type semiconducting metal oxide, titanium oxide, tin oxide, zinc oxide, or compound particles containing a plurality of these, or a mixture, each of which is made of particles with a primary particle diameter of 100 nm or less, can be used.

Furthermore, when the deterioration prevention layer 18 is provided, it is preferable that the electrochromic layer 13 is made of a material that changes color by an oxidation reaction. As a result, the n-type semiconductive metal oxide is easily reduced (electron injection) at the same time as the electrochromic layer undergoes an oxidation reaction, and the driving voltage can be reduced.
In such a case, the particularly preferred electrochromic material is an organic polymer material, which can be easily formed into a film by a coating process or the like, and allows adjustment and control of the color by the molecular structure. Specific examples of these organic polymer materials are reported in, for example, "Chemistry of Materials review 2011.23, 397-415 Navigating the Color Palette of Solution-Processable Electrochromic Polymers (Reynolds)", "Macromolecules 1996.29 7629-7630 (Reynolds)", and "Polymer journal, Vol. 41, No. 7, Electrochromic Organic Metallic Hybrid Polymers".
Examples of these organic polymer materials include poly(3,4-ethylenedioxythiophene)-based materials, and complex-forming polymers of bis(terpyridines) and iron ions.

On the other hand, examples of materials for the highly transparent p-type semiconductor layer as the degradation prevention layer 18 include organic materials having a nitroxyl radical (NO radical), such as derivatives of 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) or polymer materials of the derivative.
The anti-deterioration layer 18 is not particularly limited, and an anti-deterioration layer material may be mixed into the gel electrolyte layer 14 to impart an anti-deterioration function to the gel electrolyte layer 14. In this case, the layer structure will be similar to that of the electrochromic element 10 of the first embodiment shown in Figures 1A, 1B, and 1C.

The method for forming the deterioration prevention layer 18 is not particularly limited and may be appropriately selected depending on the purpose. Examples of the method include vacuum deposition, sputtering, and ion plating. In addition, as long as the material of the deterioration prevention layer 18 can be applied, examples of the method include various printing methods such as spin coating, casting, microgravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, slit coating, capillary coating, spray coating, nozzle coating, gravure printing, screen printing, flexographic printing, offset printing, reverse printing, and inkjet printing.

<Electrochromic Element According to Modification 2 of the First Embodiment>
The electrochromic element of the second modification of the first embodiment is an electrochromic element having a layer structure different from that of the first embodiment. Note that in the second modification of the first embodiment, the description of the same components as those of the already described embodiment may be omitted.

3A, 3B, and 3C are cross-sectional views illustrating an electrochromic element 30 according to Modification 2 of the first embodiment. Referring to Fig. 3A, 3B, and 3C, the electrochromic element 30 according to Modification 2 of the first embodiment differs from the electrochromic element 20 according to Modification 1 of the first embodiment (see Figs. 2A, 2B, and 2C) in that the second support 16 is omitted and a protective layer 17 is formed on the second electrode layer 15.
The protective layer 17 formed on the second electrode layer 15 can be made of the same material as that mentioned for the protective layer 17 formed on the side surface. However, the material of the protective layer 17 formed on the second electrode layer 15 may be the same as or different from the material of the protective layer 17 formed on the side surface. Since the electrochromic element 30 of the third embodiment is made of a single support, it can be thinned and produced at low cost.

FIG. 3C is a cross-sectional view showing a state after an optical lens of the electrochromic element 30 according to the second modification of the first embodiment has been bonded.
The electrochromic element 30 of this variant 2 of the first embodiment is similar to variant 1 of the first embodiment, except that an optical lens 21 is adhered to one outer surface of the laminate (electrochromic element 30) and a first support 11 is provided on the other outer surface, and therefore a detailed description thereof will be omitted.

<Electrochromic Element According to Modification 3 of the First Embodiment>
The electrochromic element of the third modification of the first embodiment is an electrochromic element having a layer structure different from that of the first embodiment. Note that in the third modification of the first embodiment, the description of the same components as those of the embodiments already described may be omitted.

4A, 4B, and 4C are cross-sectional views illustrating an electrochromic element 40 according to Modification 3 of the first embodiment. Referring to Fig. 4A, 4B, and 4C, the electrochromic element 40 according to Modification 3 of the first embodiment differs from the electrochromic element 30 according to Modification 2 of the first embodiment (see Figs. 3A, 3B, and 3C) in that the positions of the electrochromic layer 13 and the anti-degradation layer 18 are reversed.
In the electrochromic element 40 of the third modified example of the first embodiment, the arrangement of the constituent layers is different, but by applying a voltage between the first electrode layer 12 and the second electrode layer 15, the electrochromic layer 13 undergoes an oxidation-reduction reaction by the exchange of electric charge, and can develop or fade color.

FIG. 4C is a cross-sectional view showing a state after an optical lens of the electrochromic element 40 according to the third modification of the first embodiment has been bonded.
The electrochromic element 40 of this variant example 3 of the first embodiment is similar to variant example 1 of the first embodiment, except that an optical lens 21 is adhered to one outer surface of the laminate (electrochromic element 40) and a first support 11 is provided on the other outer surface, and therefore a detailed description thereof will be omitted.

<Electrochromic Element According to Modification 4 of the First Embodiment>
In the fourth modification of the first embodiment, an electrochromic element in which an optical lens 21 is formed so as to embed the electrochromic element as illustrated in Fig. 1B of the first embodiment is exemplified. Note that in the fourth modification of the first embodiment, the description of the same components as those in the already described embodiments may be omitted.

5 is a cross-sectional view illustrating an electrochromic element 50 according to Modification 4 of the first embodiment. Referring to FIG. 5, an optical lens 21 is formed so as to embed the electrochromic element 50.
The electrochromic element 50 is placed so as to be immersed in molten transparent resin, and while maintaining this state, the molten resin is cooled and then re-hardened, or hardened by applying light or heat, thereby forming an optical lens 21 so as to embed the electrochromic element 50.

<Electrochromic Element According to Modification 5 of the First Embodiment>
In the fifth modification of the first embodiment, an electrochromic element 60 is illustrated in which the electrochromic element and the optical lens 21 illustrated in Fig. 1B of the first embodiment are bonded via an adhesive layer 19. Note that in the fifth modification of the first embodiment, the description of the same components as those in the already described embodiments may be omitted.

Fig. 6 is a cross-sectional view illustrating an electrochromic element 60 according to a fifth modified example of the first embodiment. Referring to Fig. 6, an optical lens 21 is bonded to a second support 16 via an adhesive layer 19. This allows the optical lens 21 to be produced independently of the production process of the electrochromic element 60, and an optimal production method for the optical lens can be used, making it easy to produce a high-precision product. In addition, inventory management can be performed independently, making it easy to produce a wide variety of products in small quantities.
The material for the adhesive layer 19 is not particularly limited and can be appropriately selected depending on the purpose. Examples of the material include transparent materials such as epoxy resins, urethane resins, acrylic resins, vinyl acetate resins, and modified polymers.
The average thickness of the adhesive layer is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 3 μm or more and 200 μm or less.

<Electrochromic element according to the second embodiment>
The second embodiment is an embodiment in which a gel electrolyte is permeated into the electrochromic layer in the electrochromic element illustrated in Fig. 1A, which is the first embodiment. The electrochromic layer may be porous, and the gel electrolyte may permeate into the pores.

(Electrochromic light control element)
The electrochromic light control element of the present invention has the electrochromic element of the present invention.
Examples of the electrochromic light control element include anti-glare mirrors and light control glass.

(Electrochromic Device)
The electrochromic device of the present invention comprises the electrochromic element of the present invention or the electrochromic light control element of the present invention, and further comprises other means as necessary.
The other means are not particularly limited and can be appropriately selected depending on the application. Examples of the other means include a power source, a fixing means, and a control means.
Examples of electrochromic devices include photochromic glasses, binoculars, opera glasses, bicycle goggles, watches, electronic paper, electronic albums, and electronic billboards.

Here, Fig. 7 is a perspective view showing electrochromic light control glasses having an electrochromic light control element of the present invention. Referring to Fig. 7, electrochromic light control glasses 150 have an electrochromic light control element 51, a glasses frame 52, a switch 53, and a power source 54. The electrochromic light control element 51 is obtained by processing the electrochromic light control element of the present invention into a desired shape.
The two electrochromic light control elements 51 are incorporated in a spectacle frame 52. The spectacle frame 52 is provided with a switch 53 and a power source 54. The power source 54 is electrically connected to the first electrode and the second electrode via the switch 53 and wiring (not shown).
By switching the switch 53, it is possible to select one of the following states: a state in which a positive voltage is applied between the first electrode and the second electrode, a state in which a negative voltage is applied, or a state in which no voltage is applied.
The switch 53 may be any type of switch, such as a slide switch or a push switch, provided that the switch is capable of switching between at least the three states described above.
Any DC power source such as a button battery, a solar cell, etc. can be used as the power source 54. The power source 54 is capable of applying a voltage of about plus or minus several volts between the first electrode and the second electrode.
For example, when a positive voltage is applied between the first electrode and the second electrode, the two electrochromic light control elements 51 develop a predetermined color, and when a negative voltage is applied between the first electrode and the second electrode, the two electrochromic light control elements 51 lose their color and become transparent.
However, depending on the characteristics of the material used in the electrochromic layer, it may develop color by applying a negative voltage between the first and second electrodes, and become transparent by applying a positive voltage. Note that once a color is developed, the color will continue to develop even if no voltage is applied between the first and second electrodes.

The present invention will be described below with examples, but the present invention is not limited to these examples.

Example 1
<Preparation of electrochromic element>
Example 1 shows an example of producing an electrochromic element 10 shown in Figures 1A, 1B, and 1C. The electrochromic element 10 produced in Example 1 can also be used as a photochromic lens element.

--Formation of the first electrode layer and the electrochromic layer--
First, an elliptical polycarbonate resin substrate (AD5503, softening point 145° C., manufactured by Teijin Limited) having a maximum major axis length of 80 mm, a maximum minor axis length of 55 mm and a thickness of 0.5 mm was prepared as the first support 11 .
An ITO film was formed on the first support by sputtering to a thickness of about 100 nm, forming a first electrode layer 12 .
Next, a titanium oxide nanoparticle dispersion (product name: SP210, manufactured by Showa Titanium Co., Ltd., average particle size: 20 nm) was applied to the surface of the ITO film by spin coating, and annealing treatment was performed at 120° C. for 15 minutes to form a nanostructure semiconductor material consisting of a titanium oxide particle film with a thickness of approximately 1.0 μm.
Next, a 2,2,3,3-tetrafluoropropanol solution containing 1.5 mass % of an electrochromic compound represented by the following structural formula A was applied by spin coating, and then annealed at 120° C. for 10 minutes to support (adsorb) the electrochromic compound on the titanium oxide particle film, thereby forming an electrochromic layer 13.

[Structural Formula A]

Subsequently, a dispersion of _SiO2 particles having an average primary particle size of 20 nm (silica solid concentration 24.8% by mass, polyvinyl alcohol 1.2% by mass, and water 74% by mass) was spin-coated onto the electrochromic layer 13 to form an insulating inorganic particle layer having a thickness of 2 μm.

--Formation of the second electrode layer--
As the second support 16, a polycarbonate resin substrate having the same shape and thickness as the first support 11 was prepared.
An ITO film was formed on the second support 16 by sputtering to a thickness of about 100 nm, forming a second electrode layer 15 .

- Preparation of gel electrolyte layer -
A polymerizable material (V3877, manufactured by Daido Chemical Industry Co., Ltd.) and an electrolyte (1-ethyl-3-methylimidazolium tetracyanoborate, EMITCB) were mixed in a mass ratio of 20:80 on the surface of a release-treated PET film (NP75C, manufactured by PANAC Corporation), and a solution in which a photopolymerization initiator (irgacure 184, manufactured by Nippon Kayaku Co., Ltd.) was mixed at 0.5 mass % relative to the polymerizable material was applied to the surface of the release-treated PET film (NP75A, manufactured by PANAC Corporation). The solution was then bonded to a release-treated PET film (NP75A, manufactured by PANAC Corporation) and cured with ultraviolet (UV) light to produce a gel electrolyte layer.

--Preparation of laminate--
The release film was peeled off from the prepared gel electrolyte layer, and the layer was laminated to the surface of the insulating inorganic fine particle layer. Thereafter, the surface of the second electrode layer of the second support was aligned and laminated to the surface of the gel electrolyte layer to prepare a laminate.

- Formation of protective layer -
Next, an ultraviolet-curing adhesive (product name: KARAYAD R604, manufactured by Nippon Kayaku Co., Ltd.) was dropped onto the side surface of the laminated body, and cured by ultraviolet irradiation to form a protective layer 17 with a thickness of 3 μm.
In this manner, an electrochromic element 10 before thermoforming shown in FIG. 1A was produced.

- 3D thermoforming -
The electrochromic element before thermoforming was sandwiched between a convex mold and a concave mold having a radius of curvature of about 130 mm while being heated at 135° C., thereby producing a thermoformed electrochromic element 10 having a 3D spherical shape as shown in FIG. 1B. The mold temperature was 146° C.
The mold temperature must be set close to the softening temperature of each support material, and if it is lower than that, sufficient shaping cannot be achieved. If it is too high, it takes a long time to cool down, which reduces productivity.

- Adhesive formation of optical lenses -
A polycarbonate resin (Iupilon CLS3400, manufactured by Mitsubishi Engineering Plastics Corporation) was used as the material for the optical lens to be bonded to the prepared electrochromic element, and the electrochromic element after thermoforming was inserted into a mold and integrally molded into a lens shape by injection molding (see FIG. 1C ).
After that, the surface of the optical lens part formed by bonding the electrochromic element was cut to give it a curvature. Furthermore, both the electrochromic element and the optical lens were cut to a size that could be fitted into an eyeglass frame.

＜Evaluation＞

- Phase separation temperature of gel electrolyte layer -
The gel electrolyte layer was placed on a hot plate and heated. The membrane surface was visually observed, and the temperature at which liquid was generated on the surface of the gel electrolyte layer was recorded and used as the phase separation temperature. The phase separation temperature of the gel electrolyte layer produced in Example 1 was measured and was found to exceed 200° C., so the measurement was stopped. The results are shown in Table 1.

- Peeling -
The electrochromic element to which the optical lens was attached was visually observed for the presence or absence of peeling, and was evaluated according to the following evaluation criteria. The results are shown in Table 1.
◯: No visible peeling occurs ×: Visible peeling occurs

(Examples 2 to 27 and Comparative Examples 1 to 12)
Electrochromic elements of Examples 2 to 27 and Comparative Examples 1 to 12 were produced in the same manner as in Example 1, except that the polymerizable material used in the gel electrolyte layer in Example 1 was produced based on the composition and mass ratio shown in Table 1. Note that 1-ethyl-3-methylimidazolium tetracyanoborate (EMIMTCB) was used as the electrolyte, and irgacure 184 (manufactured by Nippon Kayaku Co., Ltd.) was used as the photopolymerization initiator in a mixed formulation of 0.5 mass % relative to the total amount of acrylate.
Next, for the electrochromic devices prepared in Examples 2 to 27 and Comparative Examples 1 to 12, the phase separation temperature and peeling of the gel electrolyte layer were evaluated in the same manner as in Example 1. The results are shown in Table 1.

表１中の略号の詳細については、以下に示すとおりである。

Details of the abbreviations in Table 1 are as follows:

-Others (Resin)-
・V3877 (manufactured by Daido Chemical Industry Co., Ltd.)
- Urethane acrylate -
-UXF4002 (manufactured by Nippon Kayaku Co., Ltd.)
・UV3000B (Mitsubishi Chemical Corporation)
・UN9200A (manufactured by Negami Industrial Co., Ltd.)
・UV3200B (Mitsubishi Chemical Corporation)
・UN350 (manufactured by Negami Industrial Co., Ltd.)
・UXT6100 (manufactured by Nippon Kayaku Co., Ltd.)
-UX5000 (manufactured by Nippon Kayaku Co., Ltd.)
・UX4101 (manufactured by Nippon Kayaku Co., Ltd.)

-PEO acrylate (resin having polyethylene oxide (PEO) chains)-
PEG400 (manufactured by Nippon Kayaku Co., Ltd.)
・A400 (manufactured by Shin-Nakamura Chemical Co., Ltd.)
・A600 (manufactured by Shin-Nakamura Chemical Co., Ltd.)
・A1000 (manufactured by Shin-Nakamura Chemical Co., Ltd.)
・AM-90G (manufactured by Shin-Nakamura Chemical Co., Ltd.)
・AM-130G (manufactured by Shin-Nakamura Chemical Co., Ltd.)
・AM-230G (manufactured by Shin-Nakamura Chemical Co., Ltd.)
・TA-210 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)

-PMMA acrylate (resin having polymethyl methacrylate (PMMA) chain)-
・AA-6 (manufactured by Toagosei Co., Ltd.)

(Examples 28 to 71 and Comparative Example 13)
In Example 1, the electrochromic elements of Examples 28 to 71 and Comparative Example 13 were produced in the same manner as in Example 1, except that the polymerizable material used in the gel electrolyte layer was prepared based on the composition and mass ratio shown in Table 2, and the electrolyte used in the gel electrolyte layer was the electrolyte shown in Table 2. Note that, as the photopolymerization initiator, Irgacure 184 (manufactured by Nippon Kayaku Co., Ltd.) was mixed and formulated at 0.5 mass % relative to the total amount of acrylate or the amount of other polymerizable material (V3877) added.
Next, for the electrochromic devices prepared in Examples 28 to 71 and Comparative Example 13, the phase separation temperature and peeling of the gel electrolyte layer were evaluated in the same manner as in Example 1. The results are shown in Table 2.

The softening point of AD5503 (manufactured by Teijin Limited) used as the support was 145°C, and the temperature of the thermoforming mold was 146°C.
The softening point of the support means the temperature at which the resin constituting the support begins to deform. The softening point of the support was determined by applying heat to the support using a needle probe with a TMA (thermomechanical analysis) device (manufactured by Kobelco Research Institute, Ltd.) and measuring the amount of displacement of the resin constituting the support.
Details of the abbreviations in Table 2 are as follows:

-Electrolytes-
EMITTCB (ethyl methylimidazolium tetracyanoborate, manufactured by Merck)
EMITFSI (ethylmethylimidazolium bistrifluoromethanesulfonimide, manufactured by Kanto Chemical Co., Ltd.)
EMIMFSI (1-ethyl-3-methylimidazolium bisfluorosulfonylimide, manufactured by Kanto Chemical Co., Ltd.)
EMIMBF4 (1-ethyl-3-methylimidazolium tetrafluoroborate, manufactured by Tokyo Chemical Industry Co., Ltd.)
・EMIMDCA (1-ethyl-3-methylimidazolium dicyanamide, manufactured by Tokyo Chemical Industry Co., Ltd.)
BMIMTFSI (1-butyl-3-methylimidazolium bistrifluoromethanesulfonylimide, manufactured by Tokyo Chemical Industry Co., Ltd.)
BMIMFSI (1-butyl-3-methylimidazolium bisfluorosulfonylimide, manufactured by Kanto Chemical Co., Ltd.)

(Examples 72 to 92)
In Example 1, the electrochromic elements of Examples 72 to 92 were produced in the same manner as in Example 1, except that the polymerizable material used in the gel electrolyte layer was prepared based on the composition and mass ratio shown in Table 3, EMIMTFSI (ethyl methyl imidazolium bistrifluoromethanesulfonimide, manufactured by Kanto Chemical Co., Ltd.) was used as the electrolyte used in the gel electrolyte layer, and the resin shown in Table 3 was used as the support and thermoformed at the molding temperature shown in Table 3. In addition, as the photopolymerization initiator, irgacure 184 (manufactured by Nippon Kayaku Co., Ltd.) was mixed and formulated at 0.5 mass% with respect to the total amount of acrylate or the amount of other polymerizable material (V3877) added.
Next, for the electrochromic devices of Examples 72 to 92 thus fabricated, the phase separation temperature and peeling of the gel electrolyte layer were evaluated in the same manner as in Example 1. The results are shown in Table 3.

表３中の略号の詳細については、以下に示すとおりである。

Details of the abbreviations in Table 3 are as follows:

- Support -
SP5570, SP5571, SP5572, SP5573 (polycarbonate resin substrate, softening point 142°C, manufactured by Teijin Limited)
SH1126, SH1127, SH1128, SH1129 (polycarbonate resin substrate, softening point 131°C, manufactured by Teijin Limited)
APL5013VH, APL5014VH, APL5015VH, APL5016VH (cyclic olefin copolymer resin substrate, softening point 129°C, manufactured by Mitsubishi Chemical Corporation)

For example, aspects of the present invention are as follows.
<1> An electrochromic element having a laminate including a resin support, a first electrode layer, an electrochromic layer, and a second electrode layer provided in this order,
A gel electrolyte is provided between the first electrode layer and the second electrode layer,
The electrochromic element is characterized in that the phase separation temperature of the gel electrolyte is higher than the softening point of the support.
<2> The electrochromic element according to <1>, further comprising a degradation prevention layer between the first electrode layer and the second electrode layer.
<3> The electrochromic element according to any one of <1> and <2>, wherein the gel electrolyte contains a binder resin, and the binder resin contains a urethane resin unit.
<4> The electrochromic element according to any one of <1> to <3>, wherein the gel electrolyte contains a binder resin, and the binder resin contains at least one selected from a polyethylene oxide (PEO) chain and a polymethyl methacrylate (PMMA) chain.
<5> The electrochromic element according to any one of <1> to <4>, wherein the solid content of the gel electrolyte is 50 mass % or less.
<6> The electrochromic element according to any one of <1> to <5>, wherein the gel electrolyte contains an ionic liquid.
<7> The electrochromic element according to <6>, wherein the gel electrolyte contains an ionic liquid in an amount of 50 mass % or more.
<8> The electrochromic element according to any one of <1> to <7>, wherein the gel electrolyte has a phase separation temperature of 160° C. or higher.
<9> The electrochromic element according to any one of <1> to <8>, wherein a difference between a phase separation temperature of the gel electrolyte and a softening point of the support is 10° C. or more.
<10> The electrochromic element according to any one of <1> to <9>, wherein the support has a softening point of 200° C. or lower.
<11> The electrochromic element according to any one of <1> to <10>, wherein the support contains at least one resin selected from the group consisting of a polycarbonate resin, a polyethylene terephthalate resin, a polymethyl methacrylate resin, a urethane resin, a polyolefin resin, and a polyvinyl alcohol resin.
<12> The electrochromic element according to any one of <1> to <11>, wherein the gel electrolyte is a lamellar gel electrolyte layer having a thickness of 30 μm or more and 150 μm or less.
<13> The electrochromic element according to any one of <1> to <12>, wherein the laminate has an optical lens on at least one surface.
<14> The electrochromic element according to any one of <1> to <13>, wherein the laminate has a desired curved surface formed by thermoforming.
<15> A method for producing the electrochromic device according to any one of <1> to <14>,
A step of thermoforming the produced laminate so as to have a desired curved shape;
and forming an optical lens on the laminate.
<16> The method for producing an electrochromic element according to <15>, wherein the heating temperature in the thermoforming is equal to or higher than the softening point of the support of the laminate.
<17> An electrochromic light control device comprising the electrochromic element according to any one of <1> to <14>.
<18> An electrochromic photochromic lens comprising the electrochromic photochromic element according to <17>.
<19> An electrochromic device comprising the electrochromic element according to any one of <1> to <14> or the electrochromic light control element according to <17>.
<20> The electrochromic device according to <19>, wherein the electrochromic device is a photochromic spectacles, a binocular, an opera glass, a bicycle goggle, a watch, an electronic paper, an electronic album, or an electronic billboard.

The electrochromic element described in any one of <1> to <14>, the manufacturing method for an electrochromic element described in any one of <15> to <16>, the electrochromic photochromic element described in <17>, the electrochromic photochromic lens having a substrate described in <18>, and the electrochromic device described in any one of <19> to <20> can solve the above-mentioned problems in the past and achieve the object of the present invention.

REFERENCE SIGNS LIST 10 Electrochromic element 11 First support 12 First electrode layer 13 Electrochromic layer 14 Gel electrolyte layer 15 Second electrode layer 16 Second support 17 Protective layer 18 Deterioration prevention layer 19 Adhesive layer 20 Electrochromic element 21 Optical lens 30 Electrochromic element 40 Electrochromic element 50 Electrochromic element 51 Electrochromic dimming element 150 Electrochromic dimming glasses

JP 2005-514647 A Japanese Patent Application Laid-Open No. 07-175090 JP 2018-10106 A

Claims (17)

An electrochromic element having a laminate having a desired curved surface shape, the laminate being formed by sequentially providing a resin support, a first electrode layer, an electrochromic layer, and a second electrode layer,
A gel electrolyte is provided between the first electrode layer and the second electrode layer,
the gel electrolyte contains a binder resin, the binder resin contains a urethane resin unit,
the phase separation temperature of the gel electrolyte is higher than the softening point of the support;
An electrochromic element, wherein the difference between the phase separation temperature of the gel electrolyte and the softening point of the support is 10° C. or more. The electrochromic element according to claim 1, further comprising an anti-deterioration layer between the first electrode layer and the second electrode layer. The electrochromic element according to any one of claims 1 to 2, wherein the gel electrolyte contains a binder resin, and the binder resin contains at least one selected from a polyethylene oxide (PEO) chain and a polymethyl methacrylate (PMMA) chain. The electrochromic device according to any one of claims 1 to 3, wherein the solid content of the gel electrolyte is 50% by mass or less. The electrochromic device according to any one of claims 1 to 4, wherein the gel electrolyte contains an ionic liquid. The electrochromic element according to claim 5, wherein the gel electrolyte contains 50% by mass or more of an ionic liquid. The electrochromic element according to any one of claims 1 to 6, wherein the phase separation temperature of the gel electrolyte is 160°C or higher. The electrochromic element according to any one of claims 1 to 7, wherein the softening point of the support is 200°C or less. The electrochromic element according to any one of claims 1 to 8, wherein the support contains at least one resin selected from the group consisting of polycarbonate resin, polyethylene terephthalate resin, polymethyl methacrylate resin, urethane resin, polyolefin resin, and polyvinyl alcohol resin. The electrochromic element according to any one of claims 1 to 9, wherein the gel electrolyte is a layered gel electrolyte layer having a thickness of 30 μm or more and 150 μm or less. An electrochromic device according to any one of claims 1 to 10, wherein the laminate has an optical lens on at least one surface. A method for producing an electrochromic device according to any one of claims 1 to 11 , comprising the steps of:
A step of thermoforming the produced laminate so as to have a desired curved shape;
and forming an optical lens on the laminate. 13. The method for producing an electrochromic device according to claim 12 , wherein the heating temperature in the thermoforming is equal to or higher than the softening point of the support of the laminate. An electrochromic light control element comprising the electrochromic element according to any one of claims 1 to 11 . An electrochromic photochromic lens comprising the electrochromic photochromic element according to claim 14 . An electrochromic device comprising the electrochromic element according to any one of claims 1 to 11 or the electrochromic light control element according to claim 14 . 17. The electrochromic device of claim 16 , wherein the electrochromic device is photochromic glasses, binoculars, opera glasses, bicycle goggles, a watch, electronic paper, an electronic album, or an electronic billboard.