JP7819682B2 - Electrochromic sheet and electrochromic device - Google Patents

Description

The present invention relates to electrochromic sheets and electrochromic devices.

Electrochromic elements are known as elements that utilize electrochromism, a phenomenon in which a reversible oxidation-reduction reaction occurs when a voltage is applied, resulting in a reversible change in transmittance. For example, applying a positive voltage to an electrochromic element causes it to develop color, and applying a negative voltage causes it to lose color and become transparent. Therefore, by providing a switch that can switch between applying positive and negative voltages, it becomes possible to color and lose color in the electrochromic element at any time.

In addition, to enhance the usability of electrochromic elements, a widely known structure is one in which an electrochromic element is sandwiched between a pair of transparent electrode layers, one for the positive electrode and one for the negative electrode. The material used for such transparent electrode layers is typically ITO (indium tin oxide), which is indium oxide doped with tin oxide, in order to achieve good light transmittance.

For example, Patent Document 1 (JP 2022-176332 A) discloses an electronic element for electronic dimming glasses, which has a pair of transparent electrode layers made of ITO and a dimming layer disposed between the pair of transparent electrode layers.

Japanese Patent Application Laid-Open No. 2022-176332

Conventionally, electrochromic elements such as those disclosed in Patent Document 1 have been used in lenses for eyewear and the like, and therefore, attention has been focused on light transmittance in order to transmit light well.
Meanwhile, with the recent rise in interest in electrochromic elements and the advancement of technology, lenses for eyewear and the like that utilize electrochromic elements are required to be able to be designed with high precision to achieve a desired color.

The present inventors have conducted extensive research with a view to increasing the degree of freedom in color design, and have found that the conventional technology disclosed in Patent Document 1, even if it has good light transmittance, leaves room for improvement in terms of the degree of freedom in color design due to the slightly yellowish reflected light.
The inventors then devised a new index for controlling such reflected light and discovered that the above problem could be solved by designing an electrochromic sheet to satisfy this index, thereby completing the present invention.

The inventors conducted extensive research to improve the freedom of color design, and as a result, devised a new index for controlling the slightly yellowish reflected light. They discovered that designing an electrochromic sheet to satisfy this index was effective, leading to the completion of this invention.

The present invention provides the following electrochromic sheet and related technology.

[1] a support layer;
an electrolyte layer provided on the support layer;
an electrochromic layer provided on at least one surface of the electrolyte layer;
a pair of transparent electrode layers positioned on the support layer so as to sandwich the electrolyte layer and the electrochemical layer;
The electrochromic sheet is configured to satisfy the following condition 1.
(Condition 1)
When the surface of the electrochromic sheet facing the support layer is irradiated with light from a D65 light source at an incident angle of 90° and the reflected light is measured at a viewing angle of 10° using a spectrophotometer, the a ^* of the reflected light in the CIE1976L ^* a ^* b ^* chromaticity coordinates is -15 to 15 and b ^* is -20 to 10.
[2] The electrochromic sheet according to [1],
An electrochromic sheet configured to further satisfy the following condition 2.
(Condition 2)
When the surface of the electrochromic sheet facing the support layer is irradiated with light from a D65 light source at an incident angle of 90° and the reflected light is measured using a spectrophotometer at a viewing angle of 10°, the L ^* of the reflected light in the CIE 1976 L ^* a ^* b ^* chromaticity coordinates is 20 to 50.
[3] The electrochromic sheet according to [1] or [2],
An electrochromic sheet configured to further satisfy the following condition 3.
(Condition 3)
The electrochromic sheet has a transmittance of 70 to 99% when the surface thereof facing the support layer is irradiated with light from a D65 light source at an incident angle of 90° and the transmitted light is measured using a spectrophotometer at a viewing angle of 10°.
[4] The electrochromic sheet according to any one of [1] to [3],
a sealing material on the support layer that covers side surfaces of the electrolyte layer and the electrochemical layer;
An electrochromic sheet configured to further satisfy the following condition 4.
(Condition 4)
Using the electrochromic sheet, a test piece (maximum length 20 mm or more) is prepared with the electrolyte layer as the center and the sealing material as the outer edge, and both ends of the test piece are chucked with chucks, and the center of the test piece is pressed with 30 N for 30 seconds, and the difference in depth between the center of the test piece before and after pressing is taken as the deformation amount (mm). The deformation amount is 0.01 mm to 0.09 mm.
[5] The electrochromic sheet according to any one of [1] to [4],
The electrochromic sheet, wherein the transparent electrode layer has a thickness of 40 to 200 nm.
[6] The electrochromic sheet according to any one of [1] to [5],
An electrochromic sheet in which at least one of the pair of transparent electrode layers has a multilayer structure.
[7] The electrochromic sheet according to any one of [1] to [6],
The electrochromic sheet, wherein the transparent electrode layer contains one or more materials selected from the group consisting of tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), zinc-doped indium oxide (IZO), silver (Ag), and a silver alloy, as well as polypyrrole, polyaniline, polythiophene, poly(p-phenylene), polyfluorene, and derivatives thereof.
[8] The electrochromic sheet according to any one of [1] to [6],
The electrochromic sheet has a single-layer or multi-layer structure, and the transparent electrode layer is made of a material selected from tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), zinc-doped indium oxide (IZO), silver (Ag), a silver alloy, and polypyrrole, polyaniline, polythiophene, poly(p-phenylene), polyfluorene, and derivatives thereof.
[9] The electrochromic sheet according to any one of [1] to [8],
An electrochromic sheet, wherein the pair of transparent electrode layers are made of different materials.
[10] The electrochromic sheet according to any one of [1] to [8],
An electrochromic sheet, wherein the pair of transparent electrode layers are made of the same material.
[11] The electrochromic sheet according to any one of [1] to [10],
The electrochromic sheet includes a support layer containing one or more resins selected from episulfide-based resins, thiourethane-based resins, acrylic-based resins, polycarbonate-based resins, urethane-based resins, polyamide-based resins, polyester-based resins, cellulose-based resins, cycloolefin polymers (COP), cycloolefin copolymers (COC), norbornene-based resins, and silicone-based resins.
[12] An electrochromic device using the electrochromic sheet according to any one of [1] to [11].

The present invention provides an electrochromic sheet that allows for greater freedom in color design.

1 is a schematic cross-sectional view showing an example of an electrochromic sheet according to an embodiment of the present invention. 1A to 1C are schematic diagrams showing a method for manufacturing a lens using the electrochromic sheet of the present embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
To avoid complexity, if there are multiple identical components in the same drawing, only one of them may be labeled with a symbol, and not all of them. All drawings are for illustrative purposes only. The shape and dimensional ratios of each component in the drawings do not necessarily correspond to the actual product.

In this specification, the notation "a to b" in the description of a numerical range means at least a and at most b, unless otherwise specified. For example, "1 to 5% by mass" means at least 1% by mass and at most 5% by mass. Furthermore, the lower and upper limits of a numerical range can be arbitrarily combined with the lower and upper limits of other numerical ranges.

Unless otherwise specified, each component and material exemplified in this specification may be used alone or in combination of two or more types.

In this embodiment, "covering" does not necessarily mean being continuous, but may also mean having discontinuous portions.

<Electrochromic sheet>
FIG. 1 is a schematic cross-sectional view showing an example of an embodiment of an electrochromic sheet 100. As shown in FIG.
As shown in FIG. 1, the electrochromic sheet 100 includes a laminate (hereinafter also referred to as an "electrochromic element 10") in which an electrolyte layer 4, a first electrochromic layer 3, and a second electrochromic layer 5 are laminated in this order, a sealing material 8 that covers the side surfaces of the electrochromic element 10, and a pair of support layers (a first transparent substrate layer 1 and a second transparent substrate layer 7) that sandwich the top and bottom surfaces of the electrochromic element 10 and the sealing material 8.
In other words, the electrochromic sheet 100 comprises a first electrochromic layer 3, an electrolyte layer 4, a second electrochromic layer 5, and a second transparent substrate layer 7 stacked in this order on a first transparent substrate layer 1, and the sides of the first electrochromic layer 3, the electrolyte layer 4, and the second electrochromic layer 5 are each covered with a sealing material 8.

Furthermore, the electrochromic sheet 100 of this embodiment has a first transparent electrode layer 2 between the first transparent substrate layer 1 and the first electrochromic layer 3, and a second transparent electrode layer 6 between the second transparent substrate layer 7 and the second electrochromic layer 5.
In other words, the electrochromic sheet 100 comprises a pair of electrode layers (a first transparent electrode layer 2 and a second transparent electrode layer 6) located on a first transparent substrate layer 1 (support layer) and sandwiching an electrochromic layer 3, an electrolyte layer, and an electrochromic layer 5. In this embodiment, the first transparent electrode layer 2 and the second transparent electrode layer 6 are transparent.
The term "transparent" means that the transmittance of transmitted light obtained by irradiating light from a D65 light source at an incident angle of 90° is 65% or more, and the haze is 3.0 or less.

1 , the electrochromic sheet 100 has first columnar conductive portions 22 and second columnar conductive portions 62 that penetrate the sealing material 8 in the thickness direction. Both the first columnar conductive portion 22 and the second columnar conductive portion 62 are electrically connected to the electrolyte layer 4.
The first columnar conductive portion 22 penetrates the sealing material 8, and reaches from the first auxiliary electrode layer 21 provided on the first transparent electrode layer 2 to the second transparent substrate layer 7. Similarly, the second columnar conductive portion 62 penetrates the sealing material 8, and reaches from the second auxiliary electrode layer 61 provided on the second transparent electrode layer 6 to the first transparent substrate layer 1.

In this embodiment, the electrochromic sheet 100 is described as having a first electrochromic layer 3 and a second electrochromic layer 5 laminated on both sides of the electrolyte layer 4, but only one of the electrochromic layers may be present.

Furthermore, while Figure 1 shows a portion of the electrochromic sheet 100, focusing on a single electrochromic element 10 and the sealing material 9 surrounding it, the electrochromic sheet 100 may also be one in which multiple electrochromic elements 10 are partitioned by sealing material 8 covering the sides of each electrochromic element 10.

The electrochromic sheet 100 of this embodiment is configured to satisfy the following condition 1. This allows for improved freedom in designing the color of the electrochromic sheet 100 and lenses and the like that use it. That is, in conventional technology, the desired color could not always be obtained even when an electrochromic sheet was colored, whereas the electrochromic sheet 100 of this embodiment can suppress the occurrence of a color in the reflected light itself by controlling the a ^* and b ^* values of the reflected light measured by a predetermined method, making it easier to obtain the desired color.
Furthermore, the electrochromic sheet 100 of this embodiment can provide good processability (mechanical strength).

(Condition 1)
When the surface of the electrochromic sheet 100 facing the first transparent substrate layer 1 (support layer) is irradiated with light from a D65 light source at an incident angle of 90° and the resulting reflected light is measured using a spectrophotometer at a viewing angle of 10°, the a ^* of the reflected light in the CIE1976L ^* a ^* b ^* chromaticity coordinates is -15 to 15 and the b ^* is -20 to 10.

Although the details of the mechanism by which such an effect is achieved are not clear, it is believed that by controlling the a ^* and b ^* values of the reflected light rather than the transmitted light, it becomes possible to highly control the apparent color of the electrochromic sheet 100, thereby obtaining the desired color and increasing the degree of freedom in design.

In condition 1, a ^* is −15 to 15, preferably −10 to 10, and more preferably −5 to 5.
In condition 1, b ^* is −20 to 10, preferably −15 to 5, and more preferably −10 to 0.

The electrochromic sheet 100 of this embodiment is further configured to satisfy the following condition 2. This allows for greater precision in the design freedom of the color of the electrochromic sheet 100 and lenses and the like that use it.

(Condition 2)
When the surface of the first transparent substrate layer 1 (support layer) of the electrochromic sheet 100 is irradiated with light from a D65 light source at an incident angle of 90° and the reflected light is measured using a spectrophotometer at a viewing angle of 10°, the L ^* of the reflected light in the CIE 1976 ^L* a ^* b ^* chromaticity coordinates is 20 to 50.

In condition 2, L ^* is 20-50, preferably 25-45, and more preferably 30-40.

The electrochromic sheet 100 of this embodiment is further configured to satisfy the following condition 3. This allows for greater precision in the design freedom of the color of the electrochromic sheet 100 and lenses and the like that use it.

(Condition 3)
The surface of the electrochromic sheet 100 facing the first transparent substrate layer 1 (support layer) is irradiated with light from a D65 light source at an incident angle of 90°, and the transmitted light is measured using a spectrophotometer at a viewing angle of 10°, resulting in a transmittance of 70 to 99%.

Under condition 3, the transmittance is 70 to 99%, preferably 75 to 99%, and more preferably 80 to 99%.

Furthermore, when the surface of the electrochromic sheet 100 facing the first transparent substrate layer 1 (support layer) is irradiated with light from a D65 light source at an incident angle of 90° and the resulting reflected light is measured using a spectrophotometer at a viewing angle of 10°, the reflectance is preferably 5 to 15%, and more preferably 8 to 12%.

In this embodiment, since the electrochromic sheet 100 has the first electrochromic layer 3 and the second electrochromic layer 5 laminated on both sides of the electrolyte layer 4, under conditions 1 to 3, the surface on the second transparent substrate layer (support layer) side may be irradiated with light from a D65 light source at an incident angle of 90° and the reflected light measured.

The electrochromic sheet 100 of this embodiment is further configured to satisfy the following condition 4. This allows for greater precision in the design freedom of the color of the electrochromic sheet 100 and lenses and the like that use it.

(Condition 4)
A test piece (maximum length 20 mm or more) is prepared using electrochromic sheet 100, with electrolyte layer 4 at the center and sealing material 8 at the outer edge. Both ends of the test piece are chucked with chucking parts, and the center of the test piece is pressed with 30 N for 30 seconds. The difference in depth between the center of the test piece before pressing and the center of the test piece after pressing is taken as the deformation amount (mm). The deformation amount is 0.01 mm to 0.09 mm.

Under condition 4, the deformation amount is 0.01 mm to 0.09 mm, preferably 0.02 to 0.08 mm, and more preferably 0.03 to 0.07 mm.

This improves mechanical strength while maintaining good processability. More specifically, even when a load is applied to the electrolyte layer 4, such as during punching or deformation of the electrochromic sheet 100 into a curved shape, surface processing for making prescription lenses, or chucking during lens cutting, deformation or denting of the electrolyte layer 4 can be suppressed.

Furthermore, it is preferable that the electrochromic sheet 100 does not have a yield point when measured under condition 4. This allows for more stable and favorable processability.

In condition 4 above, the shape of the test specimen is adjusted appropriately depending on the shape of the electrolyte layer 4 and the sealing portion 8 covering the side surface of the electrolyte layer 4, but the maximum length is at least 20 mm or more. If the test specimen is rectangular, it is preferable that one side be 20 mm or more and the other side be 30 mm or more. There are no particular upper limits on the shape of the test specimen, as long as it does not protrude beyond the stage of the measuring device. The central portion is the area including the center point of the test specimen when viewed from above.

In this embodiment, the electrochromic sheet 100 that satisfies the above conditions 1 to 4 can be prepared by a person skilled in the art by combining known methods.
For example, this can be achieved by adjusting the constituent materials, layer configuration, and thickness of the first transparent electrode layer 2 and the second transparent electrode layer 6, the combination of the first transparent electrode layer 2 and the second transparent electrode layer 6, the selection of the material for the sealing material 9, the material and manufacturing procedure for the electrolyte layer 4, the manufacturing procedure and manufacturing conditions for the electrochromic sheet 100, etc. Specifically, examples include using a material other than ITO as the constituent material for the first transparent electrode layer 2 and the second transparent electrode layer 6, or forming a multilayer structure.

The following describes in detail each component of the electrochromic sheet 100.

[Transparent electrode layer]
In this embodiment, the first transparent electrode layer 2 and the second transparent electrode layer 6 are a pair of electrode layers that sandwich the first electrochromic layer 3 , the electrolyte layer 4 , and the second electrochromic layer 5 .

The first transparent electrode layer 2 and the second transparent electrode layer 6 are electrodes that supply electrons between the first transparent electrode layer 2 and the second transparent electrode layer 6 or receive electrons from between the first transparent electrode layer 2 and the second transparent electrode layer 6 when a positive voltage or a negative voltage is applied to the first electrochromic layer 3, the electrolyte layer 4, and the second electrochromic layer 5, respectively.
The first transparent electrode layer 2 is provided on the surface of the first electrochromic layer 3 opposite to the electrolyte layer 4 side. The second transparent electrode layer 6 is provided on the surface of the second electrochromic layer 5 opposite to the electrolyte layer 4 side.

The first transparent electrode layer 2 and the second transparent electrode layer 6 may be either a single layer or a multilayer structure in which two or more layers are laminated, and it is preferable that at least one of them has a multilayer structure.
The layer structures of the first transparent electrode layer 2 and the second transparent electrode layer 6 may be the same or different, and may be symmetrical with respect to the electrolytic layer 4 .

The average thickness of the first transparent electrode layer 2 and the second transparent electrode layer 6 is adjusted so as to obtain the electrical resistance value necessary for the oxidation-reduction reaction of the first electrochromic layer 3 and the second electrochromic layer 5, and to improve the degree of freedom in design.
The thickness of the first transparent electrode layer 2 and the second transparent electrode layer 6 is preferably 40 to 200 nm, more preferably 70 to 175 nm, and even more preferably 100 to 150 nm.
By setting the thickness of the first transparent electrode layer 2 and the second transparent electrode layer 6 to be equal to or greater than the above-mentioned lower limit, the resistance value can be prevented from increasing too much, and the performance of the electrochromic sheet can be maintained. On the other hand, by setting the thickness of the first transparent electrode layer 2 and the second transparent electrode layer 6 to be equal to or less than the above-mentioned upper limit, the transmittance can be prevented from decreasing too much, and the degree of freedom in designing the appearance can be improved. Furthermore, by setting the thickness of the first transparent electrode layer 2 and the second transparent electrode layer 6 within the range from the above-mentioned lower limit to the above-mentioned upper limit, the color of reflected light can be kept transparent, and the degree of freedom in designing the lens can be improved.

Furthermore, for example, when ITO is used as the constituent material of the first transparent electrode layer 2 and the second transparent electrode layer 6, each is independently set to preferably 50 nm or more and 200 nm or less, more preferably 100 nm or more and 150 nm or less.

In addition, intermediate layers such as insulating porous layers and protective layers may be provided between the first transparent electrode layer 2 and the second transparent electrode layer 6.

The thicknesses of the first transparent electrode layer 2 and the second transparent electrode layer 6 may be the same or different. Furthermore, it is preferable that the thicknesses of the first transparent electrode layer 2 and the second transparent electrode layer 6 be set according to the constituent materials described below.

The constituent materials of the first transparent electrode layer 2 and the second transparent electrode layer 6 are not particularly limited as long as they are transparent conductive materials. For example, one or a combination of two or more selected from tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), zinc-doped indium oxide (IZO), silver (Ag) and silver alloys, as well as polypyrrole, polyaniline, polythiophene, poly(p-phenylene), polyfluorene, and derivatives thereof can be used.

The constituent materials of the first transparent electrode layer 2 and the second transparent electrode layer 6 may be the same or different. In particular, from the standpoint of improving design freedom, if one of the first transparent electrode layer 2 and the second transparent electrode layer 6 contains tin-doped indium oxide (ITO), it is preferable that the other does not contain tin-doped indium oxide (ITO), and it is even more preferable that both contain tin-doped indium oxide (ITO).

Specifically, the first transparent electrode layer 2 and the second transparent electrode layer 6 preferably have a single-layer or multi-layer structure including layers made of a material selected from tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), zinc-doped indium oxide (IZO), silver (Ag), silver alloys, and polypyrrole, polyaniline, polythiophene, poly(p-phenylene), polyfluorene, and their derivatives. In particular, from the perspective of improving design flexibility, when one of the first transparent electrode layer 2 and the second transparent electrode layer 6 includes a layer made of tin-doped indium oxide (ITO), it is preferable that the other does not include a layer made of tin-doped indium oxide (ITO). It is more preferable that both include layers made of tin-doped indium oxide (ITO), and even more preferable that the layers include two or more layers made of tin-doped indium oxide (ITO).

Examples of methods for producing the first transparent electrode layer 2 and the second transparent electrode layer 6 include vacuum deposition, sputtering, and ion plating. Furthermore, as long as the materials for the first transparent electrode layer 2 and the second transparent electrode layer 6 can be applied, examples of such methods 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.

[Electrolyte layer]
The electrolyte layer 4 is disposed between the first electrochromic layer 3 and the second electrochromic layer 5 and contains an electrolyte having ion conductivity.

The average thickness of the electrolyte layer 4 is not particularly limited, but is preferably set to approximately 20 μm or more and 100 μm or less, and more preferably 40 μm or more and 80 μm or less.

The electrolyte layer 4 contains a binder resin and an electrolyte.

The binder resin is not particularly limited and can be selected appropriately depending on the purpose, but it preferably contains a urethane resin unit in terms of the phase separation temperature and membrane strength of the polymer membrane. Furthermore, the inclusion of polyethylene oxide (PEO) chains improves compatibility with the electrolyte and increases the phase separation temperature. Furthermore, the inclusion of polymethyl methacrylate (PMMA) chains, like the inclusion of PEO chains, improves compatibility with the electrolyte and increases the phase separation temperature.

The electrolyte is not particularly limited, but examples thereof include inorganic ion salts such as alkali metal salts and alkaline earth metal salts, quaternary ammonium salts, acids, and alkali supporting salts, and specific examples thereof include _LiClO4 , _LiBF4 , LiAsF6, _LiPF6 , _LiCF3SO3 , _LiCF3COO , _KCl , _NaClO3 , NaCl, _NaBF4 , _NaSCN , _KBF4 , Mg( _ClO4 ) ₂ , Mg( _BF4 ) _2, etc., and one or more of these can be used in combination.

In addition to these, ionic liquids can also be used as electrolyte materials. Among these ionic liquids, organic ionic liquids are preferred because they have a molecular structure that allows them to remain liquid over a wide temperature range, including room temperature, and are therefore easy to handle.

As the molecular structure of the organic ionic liquid, examples of the cation component include imidazole derivatives such as N,N-dimethylimidazole salt, N,N-methylethylimidazole salt, and N,N-methylpropylimidazole salt; pyridinium derivatives such as N,N-dimethylpyridinium salt and N,N-methylpropylpyridinium salt; and aliphatic quaternary ammonium salts such as trimethylpropylammonium salt, trimethylhexylammonium salt, and triethylhexylammonium salt. Furthermore, in consideration of stability in the atmosphere, it is preferable to use a fluorine-containing compound as the anion component, such as BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , PF ₄ ⁻ , and (CF ₃ SO ₂ ) ₂ N ⁻ .

The material for such an electrolyte is preferably an ionic liquid containing any combination of cationic and anionic components.

The ionic liquid may be directly dissolved in any of the photopolymerizable monomers, oligomers, and liquid crystal materials. If the ionic liquid has poor solubility in these materials, it may be dissolved in a small amount of solvent to obtain a solution, and then this solution may be mixed with any of the photopolymerizable monomers, oligomers, and liquid crystal materials to dissolve the ionic liquid.

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

The electrolyte filled as the electrolyte layer 4 may be either solid or liquid. In addition to being a low-viscosity liquid, the electrolyte can also take various forms, such as a gel, a polymer cross-linked type, or a liquid crystal dispersion type. Among these, it is preferable to form the electrolyte in a gel or solid state. This can improve the strength and reliability of the electrochromic element 10.

A preferred method for solidifying the electrolyte layer 4 is to retain a liquid containing an electrolyte and a solvent in a binder resin. This allows the electrolyte layer 4 to have both high ionic conductivity and solid strength. Furthermore, a photocurable resin is preferred as the polymer resin. This allows the solid electrolyte layer 4 to be obtained at a lower temperature and in a shorter time than when a solid electrolyte layer 4 is obtained by thermal polymerization or solvent evaporation.

When the electrolyte layer 4 is in a gel state, it can be produced, for example, as follows.
The composition solution 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 produced by mixing an electrolytic solution obtained by mixing the ionic liquid or solid electrolyte with a solvent, a polymerizable material, a urethane acrylate monomer, and, if necessary, an acrylate monomer having a PEO chain and, if necessary, an acrylate monomer having a PMMA chain, in a desired ratio, and, if necessary, mixing the polymerization initiator and other components.
As another production method, a method can be used in which a composition solution before polymerization is applied to one electrochromic layer and polymerized by ultraviolet irradiation or heating. Also, a method can be used in which the supports on which the electrochromic layers have been formed are placed opposite each other with a gap of 5 μm to 150 μm maintained, and the composition solution is filled in, and then polymerized by ultraviolet irradiation or heating.

[Electrochromic layer]
The first electrochromic layer 3 and the second electrochromic layer 5 are layers containing an electrochromic material, and are disposed on the upper and lower surfaces of the electrolyte layer 4 so as to sandwich the electrolyte layer 4 therebetween.

The following describes the case where the second electrochromic layer 5 contains metal nanoparticles and an electrochromic material. However, even if the first electrochromic layer 3 contains metal nanoparticles and an electrochromic material, the other configurations, effects, etc. are the same, although the redox action is different.

(metal nanoparticles)
Metal nanoparticles have excellent electrical conductivity and can conduct electricity through electrochromic materials.
The metal nanoparticles may be any conductive metal particles, and specific examples include one or more selected from tin oxide, titanium oxide, zinc oxide, antimony (V) oxide, zirconium oxide, and yttrium oxide. Of these, tin oxide and titanium oxide are preferred.

The average primary particle diameter (hereinafter also referred to as "particle diameter") of the metal nanoparticles is preferably 1 nm to 100 nm, and more preferably 3 to 8 nm.
By setting the particle size to be equal to or greater than the above lower limit, good color development and decolorization performance can be obtained, whereas by setting the particle size to be equal to or less than the above upper limit, the transparency of the second electrochromic layer 5 can be maintained and the specific surface area can be increased, thereby increasing the amount of electrochromic material carried.

The electrochromic material carried by the metal nanoparticles may be one or more types of compounds.

It is preferable that the second electrochromic layer 5 be formed from a sol solution of metal nanoparticles. This allows for a good haze value and increased reflectance.

(Electrochromic materials)
The electrochromic material is composed of an electrochromic compound that undergoes an oxidation-reduction reaction when a voltage is applied, and can reversibly develop and decolorize.

The electrochromic material may be either an inorganic electrochromic compound or an organic electrochromic compound, and known electrochromic compounds such as dye-based, polymer-based, metal complex-based, and metal oxide-based compounds can be used.

The electrochromic material may be either an inorganic electrochromic compound or an organic electrochromic compound, or a conductive polymer known to exhibit electrochromism.
The first electrochromic layer 3 and the second electrochromic layer 5 can be appropriately selected from these electrochromic materials, but when one of them is made of an electrochromic material having oxidative coloring properties, it is preferable to use an electrochromic material having reductive coloring properties for the other.
As the electrochromic material having oxidative coloring properties, a polymer obtained by polymerizing an oxidative coloring electrochromic composition containing a radical polymerizable compound is preferred, and an electrochromic composition containing a radical polymerizable compound having triarylamine is particularly preferred.

The length of a single molecule of the electrochromic material is preferably 5 nm or less.

(First Electrochromic Layer)
The first electrochromic layer 3 contains, as a main material, an electrochromic material that exhibits color through an oxidation reaction, and is a layer that is colored thereby.

The average thickness of the first electrochromic layer 3 is not particularly limited, but is preferably approximately 0.1 μm or more and 30 μm or less, and more preferably approximately 0.4 μm or more and 10 μm or less.

The electrochromic material contained as the main material in the first electrochromic layer 3, which exhibits color upon oxidation, is not particularly limited and may include, for example, a polymer obtained by polymerizing a composition containing a radically polymerizable compound having triarylamine, a bisacridan compound, a Prussian blue complex, and nickel oxide, and one or more of these may be used in combination.

Examples of polymers obtained by polymerizing a composition containing a radically polymerizable compound having a triarylamine include those described in JP-A-2022-25243, JP-A-2016-45464, and JP-A-2020-138925.

Furthermore, an example of a Prussian blue type complex is a material made of Fe(III) ₄ [Fe(II)(CN) ₆ ] ₃ .

Among these, polymers obtained by polymerizing a composition containing a radically polymerizable compound having a triarylamine are particularly preferred, as they can be operated at a constant voltage, have excellent durability during repeated use, and produce electrochromic elements with high contrast.

Note that a composition containing a radically polymerizable compound having a triarylamine may also contain a radically polymerizable compound other than the radically polymerizable compound having a triarylamine, and a polymer obtained by polymerizing such a composition may be composed of a crosslinked product formed by crosslinking these radically polymerizable compounds.

(Second Electrochromic Layer)
The second electrochromic layer 5 contains, as a main material, an electrochromic material that changes from transparent to colored upon reduction reaction, and is thus a layer that is colored.

The average thickness of the second electrochromic layer 5 is not particularly limited, but is preferably approximately 0.2 μm or more and 5.0 μm or less, and more preferably approximately 1.0 μm or more and 4.0 μm or less. If the average thickness is less than 0.2 μm, it may be difficult to achieve sufficient color density depending on the type of electrochromic material. If it exceeds 5.0 μm, manufacturing costs will increase, and visibility may be reduced due to coloring depending on the type of electrochromic material.

The second electrochromic layer 5 preferably uses an electrochromic material with the same color tone as the first electrochromic layer 3. This increases the maximum color density, thereby improving contrast.

In contrast, when materials of different color tones are used, color mixing becomes possible. Furthermore, by coloring the first transparent electrode layer 2 and the second transparent electrode layer 6 through oxidation and reduction reactions on both polarity sides, the driving voltages in the electrochromic layer 3, electrolyte layer 4, and second electrochromic layer 5 can be effectively reduced, thereby improving the repeated use durability of the electrochromic sheet 100.

The electrochromic material contained as the main material in the second electrochromic layer 5, which exhibits coloration through a reduction reaction, is not particularly limited, and examples include inorganic electrochromic compounds, organic electrochromic compounds, conductive polymers, etc., and one or more of these can be used in combination.

Examples of inorganic electrochromic compounds include tungsten oxide, molybdenum oxide, iridium oxide, and titanium oxide, with tungsten oxide being preferred. Tungsten oxide has a low reduction potential, resulting in a low color development/bleaching potential, and is also an inorganic material, which means it has excellent durability, making it a preferred material.

Examples of organic electrochromic compounds include low-molecular-weight organic electrochromic compounds such as azobenzenes, anthraquinones, diarylethenes, dihydroprenes, dipyridines, styryls, styrylspiropyrans, spirooxazines, spirothiopyrans, thioindigo, tetrathiafulvalenes, terephthalic acid, triphenylmethanes, triphenylamines, naphthopyrans, viologens, pyrazolines, phenazines, phenylenediamines, phenoxazines, phenothiazines, phthalocyanines, fluorans, fulgides, benzopyrans, and metallocenes. Of these, viologen compounds and dipyridine compounds are preferred. These compounds are preferred because they have a low color development/bleaching potential and exhibit good color values.

Examples of viologen-based compounds include those described in JP 2022-025243 A, JP 3955641 A, and JP 2007-171781 A. Examples of dipyridine-based compounds include those described in JP 2007-171781 A and JP 2008-116718 A.

Examples of conductive polymers include polypyrrole, polythiophene, polyaniline, and derivatives thereof.

[Transparent base layer (support layer)]
The first transparent substrate layer 1 and the second transparent substrate layer 7 have the function of supporting the first transparent electrode layer 2, the first electrochromic layer 3, the electrolyte layer 4, the second electrochromic layer 5, the second transparent electrode layer 6, and the sealing material 8.

Furthermore, the first transparent substrate layer 1 and the second transparent substrate layer 7 constitute the outermost layers of the electrochromic sheet 100. In other words, at least the first electrochromic layer 3, electrolyte layer 4, and second electrochromic layer 5 are not exposed to the outside. This protects the first electrochromic layer 3, electrolyte layer 4, and second electrochromic layer 5 from external moisture, oxygen gas, physical impact, friction, etc.

The first transparent substrate layer 1 and the second transparent substrate layer 7 are not particularly limited as long as they are composed primarily of a transparent resin material, but it is preferable that they contain a thermoplastic transparent resin (base resin) as their primary material.

The transparent resin is not particularly limited, but examples include one or more types selected from episulfide-based resins, thiourethane-based resins, acrylic-based resins, polycarbonate-based resins, urethane-based resins, polyamide-based resins, polyester-based resins, cellulose-based resins, cycloolefin polymers (COP), cycloolefin copolymers (COC), norbornene-based resins, and silicone-based resins.

Of these, polycarbonate-based resins or polyamide-based resins are preferred, with polycarbonate-based resins being particularly preferred. Polycarbonate-based resins are highly transparent (translucent) and have excellent mechanical strength, such as rigidity, and also have high heat resistance. Therefore, using a polycarbonate-based resin as the transparent resin can improve the transparency, impact resistance, and heat resistance of the first transparent substrate layer 1 and the second transparent substrate layer 7.

A variety of resins can be used as this polycarbonate-based resin, but aromatic polycarbonate-based resins are particularly preferred. Aromatic polycarbonate-based resins have aromatic rings in their main chains, which allows the first transparent substrate layer 1 and second transparent substrate layer 7 to have greater strength.

This aromatic polycarbonate resin is synthesized, for example, by the interfacial polycondensation reaction of bisphenol and phosgene, or the transesterification reaction of bisphenol and diphenyl carbonate.

Examples of bisphenols include bisphenol A and bisphenols (modified bisphenols) that are the source of the repeating units of polycarbonate shown in formula (1A) below.

(In formula (1A), X represents an alkyl group, aromatic group, or cycloaliphatic group having 1 to 18 carbon atoms; Ra and Rb each independently represent an alkyl group having 1 to 12 carbon atoms; m and n each represent an integer from 0 to 4; and p represents the number of repeating units.)

Specific examples of bisphenols that are the source of the repeating units of the polycarbonate represented by formula (1A) include 4,4'-(pentane-2,2-diyl)diphenol, 4,4'-(pentane-3,3-diyl)diphenol, 4,4'-(butane-2,2-diyl)diphenol, 1,1'-(cyclohexanediyl)diphenol, 2-cyclohexyl-1,4-bis(4-hydroxyphenyl)benzene, 2,3-biscyclohexyl-1,4-bis(4-hydroxyphenyl)benzene, 1,1'-bis(4-hydroxy-3-methylphenyl)cyclohexane, and 2,2'-bis(4-hydroxy-3-methylphenyl)propane, and these can be used alone or in combination of two or more.

Among these, polycarbonate resins, those primarily composed of bisphenol-type polycarbonate resins having a skeleton derived from bisphenol, are preferred. By using such bisphenol-type polycarbonate resins, the first transparent substrate layer 1 and the second transparent substrate layer 7 exhibit even greater strength.

In this embodiment, the absorbance of the second transparent substrate layer 7 at a wavelength of 320 nm is preferably 1 or less, and more preferably 0.8 or less.
The absorbance of the second transparent substrate layer 7 at a wavelength of 295 nm is preferably 1 or less, and more preferably 0.8 or less.
In this embodiment, the second transparent substrate layer 7 may not contain an ultraviolet absorber. In this case, an ultraviolet blocking function can be imparted to eyewear using the electrochromic sheet 100 of this embodiment.
On the other hand, in this embodiment, the first transparent substrate layer 1 may contain a known ultraviolet absorber.

Colorant The first transparent substrate layer 1 and the second transparent substrate layer 7 may further contain a colorant as long as they have light transmittance, and the color may be colorless or any color such as red, blue, or yellow.

These colors can be selected by adding a colorant such as a dye or a pigment to the first transparent substrate layer 1 and the second transparent substrate layer 7 .
Examples of dyes include acid dyes, direct dyes, reactive dyes, and basic dyes, and one or more selected from these may be used in combination.

Specific examples of dyes include C.I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. Acid Red 52, 80, 82, 249, 254, 289, C.I. Acid Blue 9, 45, 249, C.I. Acid Black 1, 2, 24, 94, C.I. Food Black 1, 2, C.I. Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, C.I. Direct Red 1, 4, 9, 80, 81, 225, 227, C.I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, C.I. Examples include Direct Black 19, 38, 51, 71, 154, 168, 171, and 195, C.I. Reactive Red 14, 32, 55, 79, and 249, and C.I. Reactive Black 3, 4, and 35.

In addition to the transparent resin, dye, or pigment described above, the first transparent substrate layer 1 and the second transparent substrate layer 7 may also contain various additives such as antioxidants, fillers, plasticizers, light stabilizers, ultraviolet absorbers, heat absorbers, and flame retardants, as needed.

Furthermore, the first transparent substrate layer 1 and the second transparent substrate layer 7 may be stretched or non-stretched.

Furthermore, the refractive index of the first transparent substrate layer 1 and the second transparent substrate layer 7 at a wavelength of 589 nm is preferably 1.3 or more and 1.8 or less, and more preferably 1.4 or more and 1.65 or less. By setting the refractive index n1 of the first transparent substrate layer 1 and the second transparent substrate layer 7 within the above numerical range, the color-developing and color-fading function of the electrochromic sheet 100 can be easily visually recognized.

The average thickness of the first transparent substrate layer 1 and the second transparent substrate layer 7 is preferably set to 0.1 mm or more and 10.0 mm or less, more preferably 0.3 mm or more and 5.0 mm or less.
By setting the average thickness of the first transparent substrate layer 1 and the second transparent substrate layer 7 within this range, it is possible to reduce the thickness of the electrochromic sheet 100 while accurately suppressing or preventing bending of the electrochromic sheet 100.

The first transparent substrate layer and the second transparent substrate layer 7 may be made of the same constituent material or different materials. Furthermore, both may be stretched, or only one may be unstretched.

The first transparent substrate layer and the second transparent substrate layer 7 may have the same refractive index or may have different refractive indices. Furthermore, the first transparent substrate layer and the second transparent substrate layer 7 may have the same thickness or may have different thicknesses.

[Sealing material]
The sealing material 8 integrally covers the side surfaces of the electrolyte layer 4 and the side surfaces of the first electrochromic layer 3 and the second electrochromic layer 5, and is used to prevent moisture and oxygen gas from entering the electrochromic element 10 from the outside, and to adhere to the first transparent substrate layer 1 and the second transparent substrate layer 7 to prevent peeling from the electrochromic element 10. Furthermore, if the first electrochromic layer 3 and the second electrochromic layer 5 formed between the opposing first transparent electrode layer 2 and second transparent electrode layer 6 are misaligned, the color development quality during operation will deteriorate, so the sealing material 8 is used to prevent this.

The average thickness (length in the stacking direction) of the sealing material 8 is adjusted according to the average thickness of the electrochromic element 10, but is preferably set to, for example, approximately 20 μm or more and 100 μm or less, and more preferably approximately 40 μm or more and 80 μm or less.

The sealing material 8 is formed using the sealing material described below.

(Sealing material)
The sealing material of this embodiment is not particularly limited as long as it is an insulating material, but preferably contains a curable resin.

Curable Resin Examples of the curable resin include one or more selected from epoxy resin, acrylic resin, phenol resin, maleimide resin, silicone resin, urethane resin, cyanate resin, melamine resin, urea resin, and unsaturated polyester resin. Those having at least one of an ultraviolet-reactive functional group and a heat-reactive functional group are preferred, and those having a (meth)acryloyl group and/or an epoxy group are more preferred. Examples of the curable resin include thermosetting resins such as (meth)acrylate and epoxy resin.

The (meth)acrylate is not particularly limited, and examples include urethane (meth)acrylate having a urethane bond, and epoxy (meth)acrylate derived from a compound having a glycidyl group and (meth)acrylic acid.

The urethane (meth)acrylate is not particularly limited, and examples include derivatives of diisocyanates such as isophorone diisocyanate and reactive compounds that undergo an addition reaction with isocyanates, such as acrylic acid and hydroxyethyl acrylate. These derivatives may be chain-extended with caprolactone, polyols, etc.

The epoxy (meth)acrylate is not particularly limited, and examples include those obtained by reacting an epoxy compound with (meth)acrylic acid in the presence of a basic catalyst according to standard methods. Examples include epoxy (meth)acrylates derived from an epoxy resin such as a bisphenol A epoxy resin or propylene glycol diglycidyl ether and (meth)acrylic acid.

Other (meth)acrylates include, for example, one or more selected from methyl methacrylate, tetrahydrofurfuryl methacrylate, benzyl methacrylate, isobornyl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, (poly)ethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, and glycerin dimethacrylate.

Examples of the above epoxy resins include novolac-type epoxy resins such as phenol novolac-type epoxy resins and cresol novolac-type epoxy resins, bisphenol-type epoxy resins such as bisphenol A-type epoxy resins and bisphenol F-type epoxy resins, aromatic glycidylamine-type epoxy resins such as N,N-diglycidylaniline, N,N-diglycidyltoluidine, diaminodiphenylmethane-type glycidylamine, and aminophenol-type glycidylamine, hydroquinone-type epoxy resins, biphenyl-type epoxy resins, stilbene-type epoxy resins, triphenolmethane-type epoxy resins, triphenolpropane-type epoxy resins, alkyl Examples of epoxy resins include modified triphenolmethane epoxy resins, triazine nucleus-containing epoxy resins, dicyclopentadiene-modified phenol epoxy resins, naphthol epoxy resins, naphthalene epoxy resins, aralkyl epoxy resins such as phenol aralkyl epoxy resins having a phenylene and/or biphenylene skeleton, and naphthol aralkyl epoxy resins having a phenylene and/or biphenylene skeleton; and aliphatic epoxy resins such as vinylcyclohexene dioxide, dicyclopentadiene oxide, and alicyclic diepoxy adipides.

The sealing material of this embodiment may further contain inorganic particles.

Inorganic Particles Examples of inorganic particles include one or more particles selected from silica, talc, glass beads, asbestos, gypsum, diatomaceous earth, smectite, bentonite, montmorillonite, sericite, activated clay, alumina, zinc oxide, iron oxide, magnesium oxide, tin oxide, titanium oxide, calcium carbonate, magnesium carbonate, magnesium hydroxide, aluminum hydroxide, aluminum nitride, silicon nitride, barium sulfate, calcium silicate, and the like.

The inorganic particles may have their surfaces treated to be hydrophobic. For example, the inorganic particles can be surface-treated using epoxysilane, aminosilane, (meth)acrylicsilane, vinylsilane, methylchlorosilane, dimethylpolysiloxane, etc., using a known method. A mixture of inorganic particles that have been hydrophobically treated and those that have not may also be used.

The content of inorganic particles is 1 to 80% by mass, preferably 3 to 70% by mass, and more preferably 20 to 60% by mass, based on the total amount of the sealing material.

Others The sealing material of the present embodiment may contain organic particles, a polymerization initiator, a thermosetting agent, and the like in addition to the curable resin and inorganic particles.

The organic particles may be one or more types selected from the group consisting of polyester fine particles, polyurethane fine particles, vinyl polymer fine particles, acrylic polymer fine particles, silicone fine particles, and core-shell rubber fine particles.

Examples of the polymerization initiator include radical polymerization initiators and cationic polymerization initiators.

Examples of the radical polymerization initiator include photoradical polymerization initiators that generate radicals upon irradiation with light, and thermal radical polymerization initiators that generate radicals upon heating.

Examples of the photoradical polymerization initiator include benzophenone-based compounds, acetophenone-based compounds, acylphosphine oxide-based compounds, titanocene-based compounds, oxime ester-based compounds, benzoin ether-based compounds, and thioxanthone.

Examples of the thermal radical polymerization initiator include those made from azo compounds, organic peroxides, etc. Among these, polymeric azo initiators made from polymeric azo compounds are preferred.

As the cationic polymerization initiator, a photo-cationic polymerization initiator can be suitably used.
The photocationic polymerization initiator is not particularly limited as long as it generates a protonic acid or a Lewis acid upon irradiation with light, and may be either an ionic photoacid generating type or a nonionic photoacid generating type.
Examples of the photocationic polymerization initiator include onium salts such as aromatic diazonium salts, aromatic halonium salts, and aromatic sulfonium salts; and organometallic complexes such as iron-allene complexes, titanocene complexes, and arylsilanol-aluminum complexes.

The content of the polymerization initiator is preferably 0.1 to 30 parts by weight, more preferably 1 to 10 parts by weight, based on 100 parts by weight of the curable resin.
When the content of the polymerization initiator is equal to or greater than the lower limit, the sealing material has better curability, whereas when the content of the polymerization initiator is equal to or less than the upper limit, the sealing material has better storage stability.

The thermosetting agent is used to react and crosslink the thermoreactive functional groups in the curable resin by heating, and has the role of improving the adhesiveness and moisture resistance of the curable resin composition after curing.
Examples of the heat curing agent include organic acid hydrazides, imidazole derivatives, amine compounds, polyhydric phenol compounds, acid anhydrides, etc. Among these, solid organic acid hydrazides are preferably used.

The content of the thermosetting agent is preferably 0.1 to 50 parts by weight, more preferably 1 to 30 parts by weight, based on 100 parts by weight of the curable resin.
When the content of the polymerization initiator is equal to or greater than the lower limit, the curability of the sealing material is improved, whereas when the content of the polymerization initiator is equal to or less than the upper limit, the applicability of the sealing material is improved.

Other additives such as silane coupling agents, light-blocking agents, reactive diluents, spacers, curing accelerators, defoamers, leveling agents, polymerization inhibitors, and other coupling agents may also be added as needed.

(Method for producing sealing material)
Examples of a method for producing the sealing material of the present embodiment include a method of using a mixer to mix a curable resin, inorganic particles, and additives such as a polymerization initiator and/or a heat curing agent or a silane coupling agent, which are added as needed.
Examples of the mixer include a homodisper, a homomixer, a universal mixer, a planetary mixer, a kneader, a three-roll mill, and a planetary mixer.

[Columnar conductive part]
The first columnar conductive portion 22 is provided as wiring so as to overlap, in plan view, with the first transparent electrode layer 2 extending from the electrochromic element 10, and to penetrate the sealing material 8 (see FIG. 1 ). The first columnar conductive portion 22 is electrically connected to the first transparent electrode layer 2 via the first auxiliary electrode layer 21.

The first columnar conductive portions 22 are exposed at the edges of the eyeglass lenses when the outer shape of the electrochromic sheet 100 is processed into the shape of eyeglass lenses in order to apply the electrochromic sheet 100 to eyeglass lenses. This allows electricity to be applied to the electrochromic element 10 from the outside via the first columnar conductive portions 22.
Similar to the first columnar conductive portions 22, the second columnar conductive portions 62 are exposed at the edge of the eyeglass lens when the outer shape of the electrochromic sheet 100 is processed into the shape of an eyeglass lens in order to apply the electrochromic sheet 100 to the eyeglass lens. This allows electricity to be applied to the electrochromic element 10 from the outside via the second columnar conductive portions 62.
In this case, the first columnar conductive portion 22 can be located on the bridge side of the eyeglass lens, and the second columnar conductive portion 62 can be located on the temple side (opposite the bridge side) of the eyeglass lens.

Furthermore, the average thickness of the first columnar conductive portion 22 and the second columnar conductive portion 62 is preferably set independently to approximately 10 μm or more and 100 μm or less, more preferably 20 μm or more and 80 μm or less, and even more preferably 30 μm or more and 70 μm or less.

The constituent material of the first columnar conductive portion 22 and the second columnar conductive portion 62 may be a conductive paste having electrical conductivity. This improves the adhesion between the first columnar conductive portion 22 and the second columnar conductive portion 62 and the sealing material 8.

(Other electrodes)
The first auxiliary electrode layer 21 is laminated as wiring on the surface of the first transparent electrode layer 2 opposite to the first transparent substrate layer 1, and is electrically connected to the first columnar conductive portion 22.
Similarly, the second auxiliary electrode layer 61 is laminated as wiring on the surface of the second transparent electrode layer 6 opposite the second transparent substrate layer 7, and is electrically connected to the second columnar conductive portion 62.

The resistance values of the first auxiliary electrode layer 21 and the second auxiliary electrode layer 61 are set lower than the resistance values of the first transparent electrode layer 2 and the second transparent electrode layer 6, respectively. Therefore, by forming wiring electrically connected to the electrochromic element 10 using a laminate of the first transparent electrode layer 2 and the first auxiliary electrode layer 21, and a laminate of the second transparent electrode layer 6 and the second auxiliary electrode layer 61, respectively, it is possible to impart superior electrical conductivity to these wiring (laminated structures).

The constituent materials of the first auxiliary electrode layer 21 and the second auxiliary electrode layer 61 are not particularly limited as long as they have a lower resistance than the first transparent electrode layer 2 and the second transparent electrode layer 6, respectively. However, materials with excellent conductivity are used, such as silver, aluminum, copper, chromium, and molybdenum, and one or more of these can be used in combination.

Furthermore, the first auxiliary electrode layer 21 and the second auxiliary electrode layer 61 are each independently set to an average thickness of preferably approximately 1 nm or more and 100 nm or less, and more preferably approximately 5 nm or more and 50 nm or less. This ensures that the first auxiliary electrode layer 21 and the second auxiliary electrode layer 61 function as auxiliary electrodes.

[Electrochromic sheet configuration, thickness, etc.]
The total thickness of the electrochromic sheet 100 of this embodiment is not particularly limited, but is preferably 0.1 mm or more and 10.0 mm or less, and more preferably 0.3 mm or more and 5.0 mm or less.
By making the total thickness of the electrochromic sheet 100 equal to or greater than the above-mentioned lower limit, strength can be maintained, while by making the layer thickness equal to or less than the above-mentioned upper limit, the electrochromic sheet 100 can be easily processed, such as by cutting or bending.

Note that each layer of the electrochromic sheet 100 may be replaced with any other layer that can perform the same function, or other layers may be added.

<Method for manufacturing electrochromic sheet>
The method for manufacturing the electrochromic sheet 100 includes the following steps.
a step of forming a first transparent electrode layer 2 on a first transparent substrate layer 1, and laminating a first electrochromic layer 3 on the first transparent electrode layer 2;
forming a second transparent electrode layer 6 on the second transparent substrate layer 7, and forming a second electrochromic layer 5 on the second transparent electrode layer 6;
a step of applying a sealing material onto the first transparent electrode layer 2 so as to surround the outer edge of the first electrochromic layer 3, or applying a sealing material onto the second transparent electrode layer 6 so as to surround the outer edge of the second electrochromic layer 5;
a step of preparing an electrolyte layer 4, and bonding the first transparent substrate layer 1 and the second transparent substrate layer 2 together, with the first electrochromic layer 3 and the second electrochromic layer 5 facing each other with the electrolyte layer 4 interposed therebetween;
curing the sealing material to form a sealing material 8;
and
In the bonding step, the sealing material is spread out, so that the first electrochromic layer 3 and the second electrochromic layer 5 are covered with the sealing material.
As a result, the electrochromic sheet 100 is obtained.

<Method for manufacturing electrochromic lenses>
Next, each step of the manufacturing method of the lens 30 including the curved sheet 120 obtained by curvedly forming the electrochromic sheet 100 of this embodiment will be described in detail.
2 is a schematic diagram showing a method for manufacturing a lens using the electrochromic sheet of this embodiment. The upper side of FIG. 2 is referred to as "top" and the lower side of FIG. 2 is referred to as "bottom" in the following description. As shown in FIG. 2, the electrochromic sheet 110 has a plurality of electrochromic elements 10 and a sealing material 8 that surrounds them, in other words, the electrochromic sheet 110 has a plurality of electrochromic elements 10 partitioned by the sealing material 8.

(Step 1)
First, protective films 50 (masking tape) are attached to both sides of the electrochromic sheet 110 to obtain a connecting sheet laminate 210 in which the protective films 50 are attached to both sides of the electrochromic sheet 110 (see FIG. 2(a)).

(Step 2)
2(b), the connecting sheet laminate 210 is punched in its thickness direction so as to correspond to each electrochromic element 10, thereby obtaining an element laminate 250 in which the connecting sheet laminate 210 is singulated into pieces having a substantially rectangular shape in plan view. That is, with the protective films 50 attached to both sides, an electrochromic sheet 100 is obtained that is singulated into a substantially rectangular shape corresponding to each electrochromic element 10 and the sealing material 9 covering the outer edge thereof (see FIG. 1).

The shape of the individualized electrochromic sheet 100 can be various shapes, such as rectangular, circular, or elliptical. The shape to be adopted can be selected appropriately depending on the final lens 30.

(Step 3)
2(c), the singulated element stack 250 is subjected to a thermal bending process under heat to form the element stack 250 into a curved element stack 220 having a curved shape with one surface being a curved concave surface and the other surface being a curved convex surface. In this way, the flat electrochromic sheet 100 can be formed into a curved sheet 120 with the protective films 50 attached to both surfaces.

This heat bending is usually carried out by press forming or vacuum forming.
The heating temperature (forming temperature) of the element stack 250 (electrochromic sheet 100) at this time is preferably set to about 110° C. or higher and 170° C. or lower, more preferably about 130° C. or higher and 160° C. or lower. By setting the heating temperature within this range, the electrochromic sheet 100 can be softened or melted while preventing alteration or deterioration of the electrochromic sheet 100, and the electrochromic sheet 100 can be reliably thermally bent to form the curved sheet 120 having a curved shape.

(Step 4)
Next, the protective film 50 is peeled off from the thermally bent curved sheet 120. Thereafter, as shown in FIG. 2( d ), a mold 40 having a curved concave surface with a curved shape is placed in contact with the curved convex surface of the curved sheet 120, and with the curved sheet 120 adsorbed to the mold 40, a resin layer 35 (molding layer) mainly made of a resin material is injection molded onto the curved concave surface of the curved sheet 120 using, for example, insert injection molding. More specifically, with the curved sheet 120 adsorbed to the lower mold 42, an upper mold 41 is attached, and with, for example, insert injection molding, the resin layer 35 mainly made of a resin material is molded into a cavity 43, which is a space formed by the lower mold 42 and the upper mold 41.
That is, the constituent material of the resin layer 35 in a molten state is cooled and solidified while in contact with the curved concave surface of the curved sheet 120, and the resin layer 35 is molded in direct contact with the curved concave surface of the curved sheet 120 without an adhesive layer or the like interposed therebetween. In this way, the base lens 30 including the thermally bent curved sheet 120 and the resin layer 35 is manufactured.

When injection molding this resin layer 35, the heating temperature (molding temperature) of the constituent material of the resin layer 35 to bring it to a molten state is set appropriately depending on the type of constituent material of the resin layer 35. However, if the constituent material of the resin layer 35 is the same or identical to the constituent material of the transparent substrate layers (first transparent substrate layer 1 and second transparent substrate layer 7) provided in the curved sheet 120, the temperature is preferably set to approximately 180°C or higher and 320°C or lower, and more preferably 230°C or higher and 300°C or lower. Setting the heating temperature within this range ensures that the constituent material of the resin layer 35 in a molten state can be reliably supplied to the curved concave surface of the curved sheet 120.

Of the insert injection molding methods, injection compression molding is preferably used. Injection compression molding involves injecting the resin material for forming the resin layer 35 into the mold 40 at low pressure, and then closing the mold 40 at high pressure to apply a compressive force to the resin material. This is preferred because it is less likely to cause molding distortion in the molded resin layer 35, and ultimately the base lens 30, or optical anisotropy due to the local orientation of the resin molecules during molding. Furthermore, by controlling the mold compression force applied uniformly to the resin material, it is possible to cool the resin material at a constant specific volume, thereby obtaining a resin layer 35 with high dimensional accuracy.

Then, the edges of the manufactured base lens 30 are trimmed, resulting in an electrochromic lens of the desired shape.

<Electrochromic lenses>
The electrochromic lens of this embodiment is obtained by using the electrochromic sheet 100 described above.

<Electrochromic Device>
The electrochromic device of this embodiment has the above-described electrochromic lens, and further has other means as necessary. The other means are not particularly limited and can be appropriately selected depending on the application, and examples thereof include a power source, a fixing means, and a control means.
Examples of electrochromic devices include eyewear, photochromic glasses, binoculars, opera glasses, bicycle goggles, watches, electronic paper, electronic albums, electronic billboards, and anti-glare mirrors for automobiles.

The above describes embodiments of the present invention with reference to the drawings, but these are merely examples of the present invention, and various configurations other than those described above can also be adopted.

Next, the present invention will be described in detail using examples, but the content of the present invention is not limited to these examples.

(1) Preparation of Sealing Materials The following sealing materials were prepared.
Sealing material 1: epoxy acrylate resin ("Photolec S-WF17" manufactured by Sekisui Material Solutions Co., Ltd.), no heat treatment

(2) Preparation of Electrochromic Sheet <Example 1>
An electrochromic sheet as shown in FIG. 1 was produced by the following procedure.
- Formation of the first transparent electrode layer -
As a first support, a polycarbonate resin substrate (Polycaace, deflection temperature under load 140° C., manufactured by Sumitomo Bakelite Co., Ltd.) having a thickness of 0.5 mm was prepared.
An ITO film was formed on the first support by sputtering to a thickness of approximately 50 nm, and then a silver alloy film was laminated thereon to a thickness of 5 nm, and another ITO film was laminated thereon to a thickness of 50 nm to form a multilayer (IAI) to form a first transparent electrode layer.
Separately, 3 g of titanium oxide (ST-21, manufactured by Ishihara Sangyo Kaisha, Ltd.), 0.2 g of acetylacetone, and 0.3 g of a surfactant (polyoxyethylene octylphenyl ether, manufactured by Wako Pure Chemical Industries, Ltd.) were treated in a bead mill together with 5.5 g of water and 1.0 g of ethanol for 12 hours. 1.2 g of polyethylene glycol (#20,000, manufactured by NOF Corporation) was added to the resulting dispersion to prepare a paste.
The obtained paste was applied onto the first transparent electrode layer by screen printing to a thickness of 2 μm, dried at 80°C, and then subjected to UV ozone treatment at 90°C for 20 minutes to form an electron transport layer made of a porous titanium oxide particle film.

- Formation of first electrochromic layer -
Next, a 2,2,3,3-tetrafluoropropanol solution containing 1.5 mass % of a reductively color-forming electrochromic compound I represented by the following chemical formula was applied by spin coating, and then annealed at 80°C for 10 minutes to support (adsorb) the compound on the porous titanium oxide particle film, thereby forming a first electrochromic layer.

- Formation of second transparent electrode layer -
A polycarbonate resin substrate of the same shape and thickness as the first support was prepared as the second support. As in the case of the first transparent electrode, an ITO film was formed on the second support by sputtering to a thickness of approximately 50 nm, and a silver alloy film of 5 nm was then laminated on top of that, and another ITO film of 50 nm was laminated on top of that to form a multilayer (IAI) to form a second transparent electrode layer.

- Formation of second electrochromic layer -
On the second transparent electrode layer, polyethylene glycol diacrylate (PEG400DA manufactured by Nippon Kayaku Co., Ltd.) and a photoinitiator (IRGACURE 184 manufactured by BASF)
A solution was prepared by mixing a radical polymerizable compound II having a triarylamine represented by the following formula as an oxidative color-developing electrochromic material and 2-butanone in a mass ratio of 57:3:140:800. The solution was then applied to an ITO glass substrate by spin coating.

(wherein Me represents a methyl group)

Next, in a nitrogen atmosphere, UV curing was performed on the quartz substrate with the Cr layer pattern to selectively form a patterned second electrochromic layer with a thickness of 1.2 μm containing the compound represented by the radical polymerizable compound II on the second transparent electrode layer.

- Preparation of gel electrolyte -
A polymerizable material (V3877, manufactured by Daido Chemical Industry Co., Ltd.) and an electrolyte (1-ethyl-3-methylimidazolium tetracyanoborate (EMIMTCB)) were mixed in a mass ratio of 20:80 onto the surface of a release-treated PET film (NP75C, manufactured by Panac Corporation), and a solution prepared by mixing a photopolymerization initiator (irgacure 184, manufactured by Nippon Kayaku Co., Ltd.) in an amount of 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.

-Lamination process-
The release film was peeled off from the prepared gel electrolyte, and the gel electrolyte was attached to the surface of the first electrochromic layer.
Next, the prepared sealing material 1 was applied by a dispenser method so as to surround the periphery of the side surface of the first electrochromic layer.
Thereafter, the second electrochromic layer of the second support was aligned with the surface of the gel electrolyte and bonded to each other, and the sealing material was spread to cover the side surfaces of the first and second electrochromic layers. The sealing material was then irradiated with ultraviolet light at 3 J/ ^cm2 (pre-curing) and subjected to a heat curing treatment at 100°C for 1 hour (main curing), whereby the sealing material was cured to form a sealing portion, and an electrochromic sheet was produced.

Example 2
An electrochromic sheet was produced in the same manner as in Example 1, except that the first transparent electrode layer in Example 1 was formed by depositing an ITO film to a thickness of about 100 nm by sputtering.

Example 3
An electrochromic sheet was produced in the same manner as in Example 1, except that the first transparent electrode layer and the second transparent electrode layer in Example 1 were formed by depositing an ITO film to a thickness of about 130 nm by a sputtering method.

<Comparative Example 1>
An electrochromic sheet was produced in the same manner as in Example 1, except that the first transparent electrode layer and the second transparent electrode layer in Example 1 were formed by depositing an ITO film to a thickness of about 100 nm by a sputtering method.

(3) Measurement and Evaluation Next, the obtained electrochromic sheet was subjected to the following measurements and evaluations. The results are shown in Table 1.

[Optical properties]
The surface of each electrochromic sheet facing the first support layer was irradiated with light from a D65 light source at an incident angle of 90°, and the resulting reflected light was measured using a spectrophotometer at a viewing angle of 10°. The reflectance (%) and the L ^*, a*, and b ^* values of the reflected light in the CIE 1976 L ^* a ^{* b *} chromaticity coordinates were then calculated.
Similarly, the surface of each electrochromic sheet facing the first support layer was irradiated with light from a D65 light source at an incident angle of 90°, and the transmitted light obtained was measured using a spectrophotometer at a viewing angle of 10°. The transmittance (%) and the L ^*, a*, and b ^* values of the reflected light in the CIE 1976 L ^* a ^{* b *} chromaticity coordinates were then calculated.
・Spectrophotometer “V-670” manufactured by JASCO Corporation

[Deformation amount]
Using each of the obtained electrochromic sheets, a test piece (maximum length of 20 mm or more) was prepared with the electrolyte layer at the center and the sealing material at the outer edge. Both ends of the test piece were chucked with chucking parts, and the center of the test piece was pressed with 30 N for 30 seconds. The difference in depth between the center of the test piece before pressing and the center of the test piece after pressing was determined, and this was taken as the deformation amount (mm).

[Reflected color and transparency (freedom of design)]
Under bright sunlight, a skilled technician picked up each electrochromic sheet and looked through it, and evaluated the "reflected color tone" and "transparency" of the electrochromic sheet according to the following criteria.
A: Very good. There is no sense of incongruity as a spectacle lens.
B: There is a slight sense of discomfort, but there is no problem as a spectacle lens.
C: It is clearly strange to wear glasses lenses.

1 First transparent substrate layer 2 First transparent electrode layer 3 First electrochromic layer 4 Electrolyte layer 5 Second electrochromic layer 6 Second transparent electrode layer 7 Second transparent substrate layer 8 Sealant 10 Electrochromic element 21 Auxiliary electrode layer 22 Columnar conductive portion 30 Elementary lens 35 Resin layer 40 Mold 41 Upper mold 42 Lower mold 50 Protective film 61 Auxiliary electrode layer 62 Columnar conductive portion 100 Electrochromic sheet 110 Electrochromic sheet 120 Curved sheet 210 Connecting sheet laminate 220 Curved element laminate 250 Element laminate

Claims (13)

a support layer;
an electrolyte layer provided on the support layer;
an electrochromic layer provided on at least one surface of the electrolyte layer;
a pair of transparent electrode layers positioned on the support layer so as to sandwich the electrolyte layer and the electrochromic layer;
An electrochromic sheet for use in eyewear , comprising:
(Condition 1)
When the surface of the electrochromic sheet facing the support layer is irradiated with light from a D65 light source at an incident angle of 90° and the reflected light obtained is measured using a spectrophotometer at a viewing angle of 10°, the reflected light has an L ^* of 36.7 or more and 42.3 or less, a* of 2.1 or more and 12.6 or less , and b ^* of -13.2 or more and 6.9 or less in the CIE1976 ^L* a ^{* b *} chromaticity coordinates. 2. The electrochromic sheet according to claim 1 ,
An electrochromic sheet configured to further satisfy the following condition 3.
(Condition 3)
The electrochromic sheet has a transmittance of 70 to 99% when the surface thereof facing the support layer is irradiated with light from a D65 light source at an incident angle of 90° and the transmitted light is measured using a spectrophotometer at a viewing angle of 10°. 3. The electrochromic sheet according to claim 1 or 2,
a sealing material on the support layer that covers side surfaces of the electrolyte layer and the electrochromic layer;
An electrochromic sheet configured to further satisfy the following condition 4.
(Condition 4)
Using the electrochromic sheet, a test piece (maximum length 20 mm or more) is prepared with the electrolyte layer as the center and the sealing material as the outer edge, and both ends of the test piece are chucked with chucks, and the center of the test piece is pressed with 30 N for 30 seconds, and the difference in depth between the center of the test piece before and after pressing is taken as the deformation amount (mm). The deformation amount is 0.01 mm to 0.09 mm. 3. The electrochromic sheet according to claim 1 or 2,
The electrochromic sheet, wherein the transparent electrode layer has a thickness of 40 to 200 nm. 3. The electrochromic sheet according to claim 1 or 2,
An electrochromic sheet, wherein at least one of the pair of transparent electrode layers has a multilayer structure. 3. The electrochromic sheet according to claim 1 or 2,
The electrochromic sheet, wherein the transparent electrode layer contains one or more materials selected from the group consisting of tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), zinc-doped indium oxide (IZO), silver (Ag), and a silver alloy, as well as polypyrrole, polyaniline, polythiophene, poly(p-phenylene), polyfluorene, and derivatives thereof. 3. The electrochromic sheet according to claim 1 or 2,
The electrochromic sheet has a single-layer or multi-layer structure, and the transparent electrode layer is made of a material selected from tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), zinc-doped indium oxide (IZO), silver (Ag), a silver alloy, and polypyrrole, polyaniline, polythiophene, poly(p-phenylene), polyfluorene, and derivatives thereof. 3. The electrochromic sheet according to claim 1 or 2,
An electrochromic sheet, wherein the pair of transparent electrode layers are made of different materials. 3. The electrochromic sheet according to claim 1 or 2,
An electrochromic sheet, wherein the pair of transparent electrode layers are made of the same material. 3. The electrochromic sheet according to claim 1 or 2,
The electrochromic sheet includes a support layer containing one or more resins selected from episulfide-based resins, thiourethane-based resins, acrylic-based resins, polycarbonate-based resins, urethane-based resins, polyamide-based resins, polyester-based resins, cellulose-based resins, cycloolefin polymers (COP), cycloolefin copolymers (COC), norbornene-based resins, and silicone-based resins. 3. The electrochromic sheet according to claim 1 or 2,
The electrochromic sheet, wherein the transparent electrode layer has a thickness of 100 to 200 nm. 3. The electrochromic sheet according to claim 1 or 2,
The electrochromic sheet has a transparent electrode layer containing tin-doped indium oxide (ITO), and one or more materials selected from the group consisting of fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), zinc-doped indium oxide (IZO), silver (Ag), a silver alloy, and polypyrrole, polyaniline, polythiophene, poly(p-phenylene), polyfluorene, and derivatives thereof. An electrochromic device using the electrochromic sheet described in claim 1 or 2.