JP7247054B2 - electrochromic element - Google Patents

Description

The present invention relates to an electrochromic element, and an optical filter, lens unit, imaging device, and window material using the electrochromic element.

A compound whose optical properties (absorption wavelength, absorbance, etc.) change due to an electrochemical oxidation-reduction reaction is called an electrochromic (hereinafter, "electrochromic" may be referred to as "EC") compound. EC elements using EC compounds are applied to display devices, variable reflectance mirrors, variable transmission windows, and the like. EC compounds are classified into inorganic compounds and organic compounds. Of these, organic EC compounds are capable of designing and changing the absorption wavelength with a relatively high degree of freedom, and have high coloring and decoloring properties. It has the feature of being able to achieve contrast.
In a typical EC device having an organic EC compound, an EC layer containing the EC compound is arranged between a pair of electrodes, and a sealing seal holding the EC layer is arranged so as to surround the periphery of the EC layer. there is One type of typical EC device having this organic EC compound is a complementary EC device. In this complementary EC device, an anodic EC compound that is colored by oxidation and a cathodic EC compound that is colored by reduction are used as EC compounds. In a complementary EC device, when a voltage is applied between a pair of electrodes, the oxidation reaction of the anodic EC compound proceeds at the anode to form a colored body, while the reduction reaction of the cathodic EC compound proceeds at the opposing cathode. As a result, a colored body is generated and an electric current flows. Therefore, basically, the amount of the colored material of the anodic EC compound and the amount of the colored material of the cathodic EC compound are equal in the entire device.
The peripheral sealing seal that surrounds the outer periphery of the EC layer is used for the purpose of reducing leakage of the EC layer to the outside of the device and reducing the penetration of substances that cause deterioration of the EC compounds, such as moisture and oxygen, into the EC layer. . From this point of view, it is preferable that the material constituting the peripheral sealing seal has low moisture permeability, low gas permeability, and low solubility in the solvent contained in the EC layer. Patent Literature 1 discloses an EC device having excellent durability by using an epoxy novolac resin mixture as a material for forming a peripheral sealing seal.
Also, one of the important problems of EC devices is the responsiveness at the time of coloring and decoloring. As a method for improving this responsiveness, increasing the concentration of the EC compound is known.

JP 2012-168554 A

In order to improve the response speed, the present inventors studied an EC element with an increased EC compound concentration. It was found that a color difference occurs and the color inside the device becomes non-uniform. Such non-uniformity in color within the element (hereinafter sometimes referred to as "color unevenness") causes a problem because the color tone of light passing through the EC element changes.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an EC device in which color unevenness caused by a peripheral sealing seal is reduced.

The electrochromic device of the present invention is
a first electrode;
a second electrode;
a peripheral sealing seal positioned between the first electrode and the second electrode;
an electrochromic layer disposed in a space defined by the first electrode, the second electrode, and the peripheral sealing seal;
one of the first electrode and the second electrode is an anode electrode and the other is a cathode electrode;
An electrochromic device, wherein the electrochromic layer comprises an anodic electrochromic compound and a cathodic electrochromic compound,
the peripheral sealing seal is an anodic preferential peripheral sealing seal that preferentially oxidizes an anodic electrochromic compound in the vicinity of the peripheral sealing seal;
It is characterized by S _A <S _C .
S _A : area of the anode electrode defined by the peripheral sealing seal _SC : area of the cathode electrode defined by the peripheral sealing seal Further, another electrochromic device of the present invention comprises:
a first electrode;
a second electrode;
a peripheral sealing seal positioned between the first electrode and the second electrode;
an electrochromic layer disposed in a space defined by the first electrode, the second electrode, and the peripheral sealing seal;
one of the first electrode and the second electrode is an anode electrode and the other is a cathode electrode;
An electrochromic device, wherein the electrochromic layer comprises an anodic electrochromic compound and a cathodic electrochromic compound,
The peripheral sealing seal is a cathodic preferential peripheral sealing seal that prioritizes the reduction reaction of the cathodic electrochromic compound in the vicinity of the peripheral sealing seal,
It is characterized by S _C < _SA .
S _A : area defined by the peripheral sealing seal of the anode electrode _SC : area defined by the peripheral sealing seal of the cathode electrode

According to the present invention, it is possible to provide an EC device in which color unevenness caused by a peripheral sealing seal is reduced.

It is a sectional view showing typically an example of EC element concerning this embodiment. FIG. 10 is a diagram showing a typical distribution of color unevenness within the device plane caused by a peripheral sealing seal; FIG. 10 is a diagram representing a flow chart for determining the type of perimeter sealing seal. It is a figure explaining the method of defining an element center part. FIG. 4 is a diagram showing a difference in spectral shape between a coloring spectrum with preferential coloring and a coloring spectrum without preferential coloring. FIG. 4 is a diagram showing the relationship between the EC compound concentration and the degree of color unevenness caused by the peripheral sealing seal. FIG. 4 is a diagram schematically showing a mechanism of color unevenness caused by a peripheral sealing seal. FIG. 4 schematically shows the area defined by the perimeter sealing seal; 3A and 3B are a schematic diagram and an electron micrograph of the vicinity of a peripheral sealing seal. It is a figure explaining a measuring device and an evaluation method of color unevenness. It is a figure which shows typically an example of an imaging device and a lens unit. It is a figure which shows an example of a window material typically. FIG. 4 is a diagram showing the relationship between the size relationship between areas S _A and S _C defined by the peripheral sealing seal and the degree of color unevenness.

≪EC device (electrochromic device)≫
An EC device 1 according to this embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view schematically showing an example of an EC device according to this embodiment. Here, the cross section is a plane perpendicular to the element surface (electrode surface). The EC element 1 is a device that takes in light from the outside and passes the taken light through the EC layer 13 to change the intensity of the emitted light in a predetermined wavelength range.

The EC device of this embodiment has a first electrode 11a and a second electrode 11b. The first electrode 11a and the second electrode 11b may be arranged on the first substrate 10a and the second substrate 10b, respectively. In the EC device of the present invention, a peripheral sealing seal 12 is arranged between the first electrode 11a and the second electrode 11b. An EC layer (electrochromic layer) 13 is arranged in a space defined by the first electrode 11 a , the second electrode 11 b , and the peripheral sealing seal 12 . The EC layer 13 has a solvent, an anodic EC compound (anodic electrochromic compound), and a cathodic EC compound (cathodic electrochromic compound). The constituent elements of the EC device of the present invention will be described below.

<Electrodes 11a, 11b>
In the present invention, one of the first electrode 11a and the second electrode 11b is preferably transparent. Here, "transparent" means that the corresponding electrode transmits light, and the light transmittance is preferably 50% or more and 100% or less. Since at least one of the first electrode 11a and the second electrode 11b is a transparent electrode, light is efficiently taken in from the outside of the EC element and interacts with the EC compound, thereby improving the optical properties of the EC compound. This is because it can be reflected in emitted light. The term "light" used herein means light in the wavelength region targeted by the EC element. For example, if the EC element is used as a filter for an imaging device in the visible light region, the target is light in the visible light region, and if it is used as a filter for an imaging device in the infrared region, the target is light in the infrared region. Become.

The first electrode 11a and the second electrode 11b may be arranged on the first substrate 10a and the second substrate 10b, respectively. In the present invention, one of the first substrate 10a and the second substrate 10b is preferably transparent. Examples of the transparent substrate on which the electrodes 11a and 11b are arranged include glass and transparent resin. As the glass, optical glass, quartz glass, white plate glass, soda plate glass, borosilicate glass, non-alkali glass, chemically strengthened glass, etc. can be used, and in particular, non-alkali glass can be used from the viewpoint of transparency and durability. . Transparent resins include polyethylene terephthalate, polyethylene naphthalate, polynorbornene, polysulfone, polyethersulfone, polyetheretherketone, polyphenylenesulfide, polycarbonate, polyimide, polymethylmethacrylate, and the like. The non-transparent substrate on which the electrodes 11a and 11b are arranged includes an opaque resin. Examples of opaque resins include polypropylene, high-density polyethylene, polytetrafluoroethylene, polyacetal, polybutylene terephthalate, and polyamide.

As the transparent electrode, a transparent conductive oxide, a conductive layer such as dispersed carbon nanotubes, or a transparent electrode in which a metal wire is partially arranged on a transparent substrate can be used.

Examples of transparent conductive oxides include tin-doped indium oxide (ITO), zinc oxide, gallium-doped zinc oxide (GZO), aluminum-doped zinc oxide (AZO), tin oxide, antimony-doped tin oxide (ATO), and fluorine-doped tin oxide. (FTO), niobium-doped titanium oxide (TNO), and the like. Among these, FTO or ITO is preferred. When forming an electrode with a transparent conductive oxide, the film thickness is preferably 10 nm or more and 10000 nm or less. In particular, a transparent conductive oxide layer having a film thickness of 10 nm or more and 10000 nm or less and being an FTO or ITO layer is preferable. This is because it is possible to achieve both high permeability and chemical stability. The layer of the transparent conductive oxide may have a structure in which sublayers of the transparent conductive oxide are stacked. This makes it easier to achieve high conductivity and high transparency.

The metal wires that can be arranged on the substrate are not particularly limited, but wires of electrochemically stable metal materials such as Ag, Au, Pt and Ti are preferably used. A grid pattern is preferably used as the arrangement pattern of the metal wires. Electrodes with metal wires are typically planar electrodes, but curved ones can also be used if desired.

Among the first electrode 11a and the second electrode 11b, electrodes other than the transparent electrode described above are preferably selected according to the use of the EC device. For example, when the EC element is a transmissive EC element, both the first electrode 11a and the second electrode 11b are preferably transparent electrodes as described above. Furthermore, when the electrodes are arranged on the substrates, it is preferred that both the first substrate 10a and the second substrate 10b are transparent. On the other hand, when the EC element is a reflective EC element, one of the first electrode 11a and the second electrode 11b is the above-described transparent electrode, and the other is an electrode that reflects incident light. is preferred. Furthermore, when the electrodes are arranged on the substrate, it is preferable that at least the substrate on which the transparent electrodes are arranged is transparent. On the other hand, by forming a reflective layer or a scattering layer between the electrodes, it is possible to improve the flexibility of the optical properties of the electrodes other than the above-described transparent electrodes. For example, when a reflective layer or a scattering layer is introduced between the electrodes, an opaque electrode or an electrode that absorbs light can be used as the electrode behind it.

Regardless of the form of the EC device of the present invention, the constituent materials of the first electrode 11a and the second electrode 11b must be stable in the operating environment of the device and resistant to external voltage application. A material capable of rapidly advancing the oxidation-reduction reaction is preferably used according to the requirements.

As for the arrangement of the first electrode 11a and the second electrode 11b, the arrangement generally known as the electrode arrangement of the EC device can be used. As a representative example, there is an arrangement method in which the first electrode 11a and the second electrode 11b, which are respectively arranged on the substrate, are opposed to each other, and an inter-electrode distance of approximately 1 μm or more and 500 μm or less is provided. A long distance between the electrodes is advantageous in that a sufficient amount of the EC compound can be placed so as to effectively function as the EC element, and the transmittance during coloring can be reduced. On the other hand, when the inter-electrode distance is short, it is advantageous in that a high response speed can be achieved.

<EC layer 13>
The EC device of the present invention has an EC layer 13 comprising an anodic EC compound and a cathodic EC compound, preferably further comprising a solvent, between a first electrode 11a and a second electrode 11b.

[solvent]
The solvent constituting the EC layer 13 is selected depending on the application in consideration of the solubility, vapor pressure, viscosity, potential window, etc. of solutes including EC compounds, but the solvent should have polarity. is preferred. Specific examples include organic polar solvents such as ether compounds, nitrile compounds, alcohol compounds, dimethylsulfoxide, dimethoxyethane, sulfolane, dimethylformamide, dimethylacetamide, and methylpyrrolidinone, and water. Among them, solvents containing cyclic ethers such as propylene carbonate, ethylene carbonate, γ-butyrolactone, valerolactone, and dioxolane are preferably used from the viewpoint of EC compound solubility, boiling point, vapor pressure, viscosity, and potential window. Solvents containing propylene are most preferably used.

[EC compound]
In the present invention, the EC compound is a kind of oxidation-reduction substance, and is a substance whose light absorption characteristics change in the light wavelength region targeted by the device due to oxidation-reduction reaction. Further, the oxidation-reduction substance is a compound capable of repeatedly undergoing oxidation-reduction reactions within a predetermined potential range. The light-absorbing property referred to here is typically a light-absorbing state and a light-transmitting state, and the EC compound is typically a material that switches between a light-absorbing state and a light-transmitting state. The EC compound used in the EC device of the present invention is preferably an organic compound. A low-molecular-weight organic compound having a molecular weight of 2,000 or less is preferable as the organic EC compound of the present invention.

In this specification, an EC compound may be described as an "anodic EC compound" or a "cathodic EC compound". Each will be described in detail below.

(anodic EC compound)
An anodic EC compound refers to a material whose light absorption properties are changed by an oxidation reaction in which electrons are usually removed from the EC compound on the anode in the light wavelength region of interest for the device. A typical example is a material that changes from a light-transmitting state to a light-absorbing state. In this specification, in order to make it easier to imagine the change of the EC compound, the change from the light transmitting state to the light absorbing state, which is a typical example, is sometimes described. Further, in this specification, a molecule in a light transmitting state is sometimes expressed as a "decolored body", and a molecule in a light absorbing state is sometimes expressed as a "colored body". In this case, the reductant of the anodic EC compound is in a light-transmissive state in the light wavelength region targeted by the device, and is expressed as a "decolorized body". Moreover, the oxidized form of the anodic EC compound is in a light absorbing state and is expressed as a "colored body".

Examples of anodic EC compounds include thiophene derivatives, amines having an aromatic ring (e.g., phenazine derivatives, triallylamine derivatives), pyrrole derivatives, thiazine derivatives, triallylmethane derivatives, bisphenylmethane derivatives, xanthene derivatives, and fluorane. Derivatives, spiropyran derivatives. Among these, as the anodic EC molecule, amines having a low molecular weight aromatic ring are preferred, and dihydrophenazine derivatives are most preferred.

(Cathodic EC compound)
A cathodic EC compound refers to a material whose light absorption characteristics are changed by a reduction reaction in which electrons are donated from the electrode to the EC compound on the cathode in the light wavelength region of interest for the device. A typical example is a material that changes from a light-transmitting state to a light-absorbing state. In the description of this specification, the reduced form of the cathodic EC compound is in a light-absorbing state in the light wavelength region targeted by the device, and is expressed as a "colored body". Moreover, the oxidized form of the cathodic EC compound is in a light-transmitting state and is expressed as a "decolorized form".

Examples of cathodic EC compounds include pyridine-based compounds such as viologen, quinone compounds, and the like. Among them, pyridine compounds such as viologen are most preferably used.

[Method of Forming EC Layer]
As a method for introducing a solution containing an EC compound into the EC element, for example, when the facing electrodes 11a and 11b are joined, openings are formed in the electrodes 11a and 11b or part of the peripheral sealing seal 12, A subsequent infusion of the solution through the opening may be included. Specific methods for injecting a solution containing an EC compound into a cell include a vacuum injection method, an atmospheric injection method, a meniscus method, and the like. After the solution containing the EC compound is injected into the cell, the solution can be stably retained in the cell by sealing the opening.

<Peripheral sealing seal 12>
It is preferable that the first electrode 11a and the second electrode 11b are joined by a peripheral sealing seal 12 so that both electrode surfaces face each other. The peripheral sealing seal 12 serves to maintain the spatial arrangement of the first electrode 11a and the second electrode 11b, reduce leakage of the EC layer 13 to the outside of the EC element, and protect against contact with external substances. bear.

From the above point of view, the material constituting the peripheral sealing seal 12 should be chemically stable, have low moisture permeability and low gas permeability, and have low solubility in the solvent contained in the EC layer 13. It is preferably composed of For example, inorganic materials such as glass frit, organic materials such as epoxy and acrylic resins, and metals can be used. The peripheral sealing seal may have a function of defining the distance between the first electrode 11a and the second electrode 11b by, for example, containing a spacer material. If the peripheral sealing seal 12 does not have the function of defining the distance between the first electrode 11a and the second electrode 11b, a separate spacer may be arranged to maintain the distance between the two electrodes. good. Inorganic materials such as silica beads and glass fibers, and organic materials such as polyimide, polytetrafluoroethylene, polydivinylbenzene, fluororubber, and epoxy resin can be used as materials for the spacers. In this case, this spacer makes it possible to define and maintain the distance between the first electrode 11a and the second electrode 11b that constitute the EC element.

The inventors have found that either the anodic EC compound or the cathodic EC compound may preferentially color over the other in the vicinity of the peripheral sealing seal 12 in the EC layer 13 . Here, "preferentially coloring" means that when the EC element is driven and the optical density of the element reaches a stable state in which the optical density transitions around the target density, either the anodic EC compound or the cathodic EC compound It means that one coloring body is present in a larger amount than the other coloring body. For example, "the anodic EC compound is preferentially colored in the vicinity of the peripheral sealing seal 12" means that in the vicinity of the peripheral sealing seal 12, after the EC element is driven, at the stage where the optical density of the element is stabilized, the anode It shows that the color body of the cathodic EC compound is present in more than the color body of the cathodic EC compound. Specifically, it shows that the color of the colored body of the anodic EC compound is expressed more strongly than the color of the colored body of the cathodic EC compound. When the preferential coloring of the anodic EC compound or the cathodic EC compound is observed in the vicinity of the peripheral sealing seal 12 in this way, the EC is observed in the vicinity of the peripheral sealing seal 12 in the EC layer 13 and in the other regions. A difference in color occurs when the element is driven, and color unevenness occurs within the element surface.

FIG. 2 shows a typical preferential colored area distribution found near the perimeter sealing seal 12 . Here, FIG. 2 is a view looking down on the EC element from a direction perpendicular to the element surface. As shown in FIG. 2, the preferentially colored regions are generated in two regions, "peripheral sealing seal nearest neighbor 13a" and "peripheral sealing seal quasi-neighborhood 13b". Here, the "peripheral sealing seal nearest neighbor 13a" is a region of the EC layer 13 near the boundary where the peripheral sealing seal 12 and the EC layer 13 are in contact, and the "peripheral sealing seal quasi-neighborhood 13b" is the EC layer 13. It is the outer edge of the region of layer 13 that does not include the peripheral sealing seal nearest neighbor 13a. The region of "peripheral sealing seal nearest neighbor 13a" has a width of about 200 μm from the boundary of the side of the peripheral sealing seal 12 in contact with the EC layer 13, and this width hardly depends on the distance between the upper and lower electrodes. . In addition, depending on how the preferential coloring appears in the "peripheral sealing seal nearest neighbor 13a", the peripheral sealing seal 12 can be classified as an anode preferential peripheral sealing seal, a cathodic preferential peripheral sealing seal, and others that do not correspond to these two. There are three categories of peripheral sealing seals. Two of the following are the anode-preferred perimeter sealing seal and the cathode-preferring perimeter sealing seal.

[Anode preferential peripheral sealing seal]
An anodic preferential peripheral sealing seal is defined as a peripheral sealing seal 12 that exhibits preferential coloration of the anodic EC compound in the vicinity 13a of the peripheral sealing seal. Also, in the anode preferential peripheral sealing seal, preferential coloring of the cathodic EC compound occurs in the vicinity of the peripheral sealing seal 13b.

Features of the sealing material exhibiting properties as an anode-preferential peripheral sealing seal include that it is composed of a resin with relatively high polarity and that it contains an oxidizing compound.

The reason for the former is as follows. Viologen-based compounds, which are typical cathodic EC compounds, have a positive charge, while they are represented by aromatic amine-based compounds such as triphenylamines and phenazines, and thiophene-based compounds. As such, the bleaching body of the anodic EC compound has no charge. Therefore, the cathodic EC compound decolored body has a greater polarity than the anodic EC compound decolored body. As will be described later, in the peripheral sealing seal closest vicinity 13a and the peripheral sealing seal near vicinity 13b, a thin film made of a material constituting the peripheral sealing seal exists on the electrode surface. Among them, the film thickness of the thin film is relatively large in the area of the peripheral sealing seal nearest neighbor 13a compared to the area of the peripheral sealing seal quasi-neighboring area 13b. Therefore, in the region 13a closest to the peripheral sealing seal, when the peripheral sealing seal is composed of a highly polar resin, the interaction between the highly polar cathodic EC compound decolorizing body and the highly polar resin is high. , is large compared to the bleached body of the less polar anodic EC compound. As a result, the migration of the cathodic EC compound decolorizer to the electrode surface is greatly inhibited compared to the anodic EC compound decolorizer. As a result, the anodic EC compound is preferentially colored in the vicinity 13a of the peripheral sealing seal. A peripheral encapsulation seal comprising, for example, an epoxy resin may be used to meet the above characteristics.

The reason for the latter is as follows. When an oxidizing compound is contained in the peripheral sealing seal, it may add protons to the anodic EC compound present in the vicinity of the peripheral sealing seal or remove electrons from the anodic EC compound to cause oxidation. When the oxidized anodic EC compound has absorption in the visible region, the absorption derived from the oxidized colored species of the anodic EC compound appears strongly in the vicinity of the peripheral sealing seal. Examples of those that satisfy the above characteristics include peripheral sealing seals containing curing agents and curing accelerators for heat/photocurable epoxy resins and photocurable acrylic resins. Specifically, acid anhydrides , phenol-based resins, and peripheral sealing seals containing Lewis acid, which is a by-product of onium salts such as antimony-based compounds. More specific examples of curing agents and curing accelerators that can be contained in the anode preferential peripheral sealing seal include onium salts such as sulfonium salts, benzothiazolium salts, ammonium salts, and phosphonium salts; Potential thermal acid generators combined with phosphates, halogen-containing triazine compounds, diazoketone compounds, onium salt compounds, potential photoacid generators of sulfonic acid compounds, phenolic resins such as novolac resins and cresol resins. Curing agents, acid anhydrides such as phthalic anhydrides, maleic anhydrides, pyromellitic anhydrides, p-toluenesulfonate of DBU (1,8-diazabicyclo(5,4,0)-undecene-7) and phenol curing accelerators such as salts, p-toluenesulfonate and phenol salts of DBN (1,5-diazabicyclo(4,3,0)-nonene-5);

The classification of the type of the peripheral sealing seal is determined according to the method for determining the type of the peripheral sealing seal, which will be described later, regardless of whether or not the above ingredients are contained.

[Cathode preferential peripheral sealing seal]
A cathodic preferential peripheral sealing seal is defined as a peripheral sealing seal 12 that exhibits preferential coloration of the cathodic EC compound in the vicinity 13a of the peripheral sealing seal. Also, in the cathodic preferential peripheral sealing seal, preferential coloring of the anodic EC compound occurs in the vicinity 13b of the peripheral sealing seal.

The characteristics of the sealing material exhibiting properties as a cathode-preferential peripheral sealing seal include that it is composed of a material with relatively low polarity, that it contains a reducing compound, and the like.

The reason for the former is as follows. As described above, a relatively thick thin film exists on the electrode surface in the vicinity 13a of the peripheral sealing seal. Therefore, when the peripheral sealing seal is composed of a material with a low polarity, the interaction between the decolorizing body of the anodic EC compound with a low polarity and the peripheral sealing seal with a low polarity occurs in the vicinity 13a of the peripheral sealing seal nearest to the peripheral sealing seal. , is large compared to the bleaching body of the highly polar cathodic EC compound. As a result, the migration of the decolorizing body of the anodic EC compound to the electrode surface is greatly inhibited compared to the decolorizing body of the cathodic EC compound having a large polarity. As a result, the cathodic EC compound is preferentially colored in the vicinity 13a of the peripheral sealing seal. Those that meet the above characteristics include, for example, perimeter sealing seals comprising synthetic rubber.

The reason for the latter is as follows. When a reducing compound is contained in the peripheral sealing seal, the reducing compound existing on the outermost surface of the film or the eluted reducing compound may cause a reduction reaction of the cathodic EC compound existing in the vicinity of the peripheral sealing seal. be. As a result, the coloring of the cathodic EC compound appears strongly in the vicinity 13a of the peripheral sealing seal. Those that satisfy the above characteristics include, for example, peripheral sealing seals containing curing agents and curing accelerators such as low-molecular-weight amine compounds, polyamidoamines, imidazole compounds, and triarylphosphine compounds. More specific examples of curing agents and curing accelerators that may be included in the cathodic preferential peripheral sealing seal include carbamates, carbamoyloximes, aromatic sulfonamides, α-lactones, benzhydryl ammonium salts, potential photoamine generators such as imidazole salts and amidine salts; latent thermal amine generators such as piperidine carboxylates; aliphatic polyamines such as triethylenetetramine; and aromatic polyamines such as diaminodiphenylmethane. Furthermore, sensitizers such as alkylaminobenzophenone, DBU (1,8-diazabicyclo(5,4,0)-undecene-7), DBN (1,5-diazabicyclo(4,3,0)-nonene-5), etc. and the like.

The classification of the type of the peripheral sealing seal is determined according to the method for determining the type of the peripheral sealing seal, which will be described later, regardless of whether or not the above ingredients are contained.

[Method for determining the type of peripheral sealing seal]
Perimeter seals are classified as the above-mentioned anode-preferred perimeter seals, cathodic-preferred perimeter seals, and other perimeter seals that do not fit into these two. A method for making these classifications is described with reference to the flow chart of FIG.

First, a voltage is applied to the EC element to bring it into a colored state, and the coloring of the central portion of the EC element and the coloring of the closest vicinity 13a of the peripheral sealing seal are confirmed. Next, the coloration of the central portion of the EC element and the coloration of the nearest portion 13a of the peripheral sealing seal are compared. A method of defining the central portion of the EC element will be described with reference to FIG. First, the area inside the perimeter sealing seal 12 is defined by a rectangular area 14 having the largest area. A circular region 15 centered on the centroid of the rectangular region defined in this way and having a diameter ⅕ times the length of the short side of the rectangular region is defined as the central portion of the EC element.

In addition, when checking the coloring of the region 13a closest to the peripheral sealing seal, the coloring of the region in the EC layer within 1 mm from the boundary between the peripheral sealing seal and the EC layer is checked, and one of the regions is checked. When the coloration of one EC compound appears more intensely in the part or the entire region than in the central part of the EC element, it is determined that "there is preferential coloring".

From the above-mentioned conditions for defining the central portion, the coloring of the central portion of the EC element is the coloring of the EC layer in the region away from the vicinity of the peripheral sealing seal. reflects. Therefore, when the coloring of the anodic EC compound or the cathodic EC compound appears more strongly in the vicinity of the peripheral sealing seal than in the center of the EC element, it is determined that the peripheral sealing seal has preferential coloring. be done. Color comparison can be performed visually, by image analysis using a camera, or the like. Also, the coloring spectra of the central portion of the EC element and the closest vicinity 13a of the peripheral sealing seal may be acquired and compared. FIG. 5 shows an example of a coloring spectrum when there is no preferential coloring, a coloring spectrum when the anodic EC compound preferentially colors, and a coloring spectrum when the cathodic EC compound preferentially colors. Thus, during preferential coloring, the absorption corresponding to the preferentially coloring anodic EC compound or cathodic EC compound is greater than when there is no preferential coloring, and the absorption corresponding to the other EC compound is decreased. Therefore, the color changes compared to when there is no preferential coloring. Therefore, it is possible to determine the presence or absence of preferential coloring and the type of EC compound that gives preferential coloring from visual observation, image comparison, and spectral shape change. In this way, as a result of confirming the coloring of the central portion of the EC element and the closest vicinity 13a of the peripheral sealing seal, if there is no preferential coloring, the peripheral sealing seal is judged to be "another peripheral sealing seal". When preferential coloring is confirmed, the type of peripheral sealing seal is further determined by the following process.

The polarity of the voltage applied to the EC element is reversed, and the coloration in the vicinity of the peripheral sealing seal is confirmed again. At this time, when the type of EC compound (anodic EC compound/cathodic EC compound) that preferentially colors changes, the peripheral sealing seal is determined as "another peripheral sealing seal".

When the polarity reversal does not change the type of EC compound that preferentially colors, the determination is made as follows. When the EC compound that preferentially colors in the nearest vicinity 13a of the peripheral sealing seal is an anodic EC compound, the peripheral sealing seal is judged to be an "anodic preferential peripheral sealing seal". Further, when the EC compound that preferentially colors in the closest vicinity 13a of the peripheral sealing seal is a cathodic EC compound, the peripheral sealing seal is determined as a "cathode preferential peripheral sealing seal".

The reason for performing the discrimination by this polarity reversal will be described below. Even in the case of "other peripheral sealing seals" that are neither "anode preferential peripheral sealing seals" nor "cathode preferential peripheral sealing seals", if preferential coloring occurs in the vicinity of the peripheral sealing seals There is A typical example of such a case is the case where either one of the electrodes has an obstacle that impedes the migration of the EC compound to the electrode surface. In such a case, the coloring of the EC compound according to the polarity of the electrode preferentially occurs on the electrode on the side where the obstacle does not exist during the EC drive. (Such a phenomenon is sometimes referred to as electrode obstacle color unevenness.) Specifically, in a region where such an obstacle exists on the cathode and no obstacle exists on the anode, coloring of the anodic EC compound occurs. Prioritize. Also, in regions where such obstacles exist on the anode and no obstacles exist on the cathode, coloring of the cathodic EC compound takes precedence. Here, in the vicinity of the perimeter sealing seal 12, there may be a region where one electrode is covered with a thin film made of the material forming the perimeter sealing seal and the other electrode is not covered. In such a region, the electrode obstruction color unevenness remarkably appears.

Electrode obstacle color unevenness is caused by reversing the polarity of the voltage applied from the outside when the EC element is driven, so that the EC compound that preferentially colors changes to the other EC compound. Specifically, by reversing the polarity of the voltage, the preferential coloring of the anodic EC compound changes with the preferential coloring of the cathodic EC compound, and the preferential coloring of the cathodic EC compound changes with the preferential coloring of the anodic EC compound. . On the other hand, in the color unevenness caused by the anode-preferential peripheral sealing seal and the cathode-preferential peripheral sealing seal, the type of EC compound that preferentially colors does not change with respect to the polarity reversal of the voltage, so these non-preferential peripheral sealing It can be distinguished from color unevenness that occurs in the vicinity of the seal.

[Relationship between concentration of EC compound and color unevenness caused by peripheral sealing seal 12]
FIG. 6 shows the relationship between the EC compound concentration and the degree of color unevenness caused by the peripheral sealing seal 12 . The concentration of the EC compound on the horizontal axis of FIG. 6 means the sum of the concentration of the anodic EC compound and the concentration of the cathodic EC compound contained in the EC layer 13 . Incidentally, in obtaining the data shown in FIG. 6, the peripheral sealing seal 12 is the anode preferential peripheral sealing seal, and the area (S _A ) of the anode electrode defined by the peripheral sealing seal 12 is the area of the cathode electrode. Elements larger than the area (S _C ) defined by the perimeter sealing seal 12 were used. In this device, the concentration of the anodic EC compound and the concentration of the cathodic EC compound are equal. The degree of color unevenness (ΔE ₀₀ ), which is the vertical axis in FIG. 6, will be described later. From this, the degree of color unevenness caused by the peripheral sealing seal 12 increases in the EC compound concentration range of 0.1 mol/L or higher, and in the EC compound concentration range of 0.4 mol/L or higher. Furthermore, it can be seen that the degree of color unevenness increases. An object of the present invention is to reduce the degree of color unevenness caused by the peripheral sealing seal 12, and the effect of the present invention is strong in the concentration range of 0.1 mol/L or more, particularly 0.4 mol/L or more. will appear.

<<Mechanism of appearance of color unevenness caused by peripheral sealing seal 12>>
As described above, when the anodic EC compound is preferentially colored in the vicinity 13a of the peripheral sealing seal (the peripheral sealing seal 12 is an anodic preferential peripheral sealing seal), the peripheral sealing is performed at the same time. Preferential coloration of the cathodic EC compound occurs in the seal quasi-near 13b. In addition, when preferential coloring of the cathodic EC compound is observed in the peripheral sealing seal nearest neighbor 13a (the peripheral sealing seal 12 is a cathodic preferential peripheral sealing seal), at the same time Preferential coloration of the anodic EC compound occurs in 13b.

The present inventors observed and analyzed the surfaces of the electrodes 11a and 11b in the vicinity of the peripheral sealing seal 12 in order to identify the cause of such a coloring distribution when the EC element is driven. As a result, it was found that a thin film of components constituting the peripheral sealing seal 12 was formed on the surfaces of the electrodes 11a and 11b in the vicinity of the peripheral sealing seal 12. FIG. In addition, electrochemical measurements were performed on the anode-preferred perimeter sealing seals. Specifically, electrodes were prepared by forming thin films with various thicknesses, and the coloring reactivity of the anodic EC compound and the cathodic EC compound on the surface of the thin film was examined from the current during the coloring reaction, revealing the following. became.
(1) On the electrode with the thin film, the coloring reaction rate of the cathodic EC compound and the anodic EC compound is lower than that on the electrode without the thin film, and the rate increases as the film thickness increases.
(2) On the electrode with the smallest thin film thickness, the coloring reaction rate of the anodic EC compound decreases, and the magnitude relationship of the coloring reaction rate is cathodic EC compound>anodic EC compound.
(3) On an electrode with a thicker film thickness than that, the coloring reaction rate is greatly reduced, but the magnitude relationship of the coloring reaction rate is anodic EC compound > cathodic EC compound.

The above three points are experimental facts regarding the anode-preferred perimeter sealing seal. In the case of the cathode-preferred peripheral sealing seal, (1) is the same, but (2) and (3) are reversed in magnitude relation between the anode-preferential peripheral sealing seal and the coloring reaction rate. That is, when the film thickness of the thin film is small, the magnitude relationship of the coloring reaction rate is anodic EC compound>cathodic EC compound. When the film thickness of the thin film is large, the magnitude relationship of the coloring reaction rate is cathodic EC compound>anodic EC compound.

FIG. 7 is a diagram schematically showing the color unevenness development mechanism derived from these experimental facts. FIG. 7 shows the vicinity of the peripheral sealing seal 12 in the cross-sectional view of the EC device. Here, the cross section is a plane perpendicular to the element surface. FIG. 7(a) shows that the peripheral sealing seal 12 is the mechanism of color unevenness in the anode-preferred peripheral sealing seal, and FIG. is the expression mechanism of In FIG. 7, the first electrode 11a is the anode electrode and the second electrode 11b is the cathode electrode. The black "A" (A in circle) indicates the decolorized anodic EC compound, and the white "A" (A in ●) indicates the colored anodic EC compound. In addition, the black "C" (C in circles) indicates the decolored body of the cathodic EC compound, and the white "C" (C in ●) indicates the colored body of the cathodic EC compound.

As shown in FIG. 7(a), when the perimeter sealing seal 12 is an anode-preferential perimeter sealing seal, the thickness of the thin film (peripheral sealing seal 12) on the electrode is relatively small. In the vicinity 13b, more cathodic EC compound colored bodies are generated than anodic EC compound colored bodies. When the EC device is driven, both electrodes of the anode and the cathode form an electrically closed circuit, so that the amounts of the colored substances of the two compounds are basically equal in the entire device. Therefore, the colorant imbalance that occurs in the perimeter sealing seal sub-neighborhood 13b must be compensated for. This is compensated by the fact that the amount of the anodic EC compound colored body is greater than the amount of the cathodic EC compound colored body in the vicinity 13a of the peripheral sealing seal.

Further, when the peripheral sealing seal 12 is a cathode preferential peripheral sealing seal, as shown in FIG. Color bodies of anodic EC compounds occur more than those of cathodic EC compounds. Since both electrodes form an electrically closed circuit as described above, it is necessary to compensate for the imbalance of the colored bodies generated in the vicinity 13b of the peripheral sealing seal. This is compensated for by the amount of cathodic EC compound colorant being greater than the amount of anodic EC compound colorant in the vicinity 13a of the peripheral sealing seal.

<<Method of defining the electrode area defined by the peripheral sealing seal 12>>
As will be described later, in the present invention, color unevenness is improved by controlling the size relationship of the areas defined by the peripheral sealing seals 12 of the anode and cathode electrodes. There are two methods for defining the electrode area defined by the peripheral sealing seal 12 . Each will be described in detail below.

<Method of directly observing the boundary of the peripheral sealing seal 12>
FIG. 8 shows a conceptual diagram of the electrode area defined by the peripheral sealing seal 12. As shown in FIG. FIG. 8(a) is a cross-sectional view of the EC element cut in a direction perpendicular to the electrode surface. FIG. 8(b) is a top view of the EC device observed from a direction perpendicular to the electrode surface. In FIG. 8, the first electrode 11a is the anode electrode and the second electrode 11b is the cathode electrode. As shown in FIG. 8, the area defined by the peripheral sealing seal 12 is the boundary 16 between the area covered by the peripheral sealing seal 12 and the area not covered on the electrode surface (hereinafter referred to as is the area enclosed by the "perimeter sealing seal boundary"). Here, the region covered by the peripheral sealing seal 12 is defined as a region where the peripheral sealing seal 12 exists on the electrode surface with a thickness of 100 [nm] or more. The reason for this is that neither the anodic EC compound nor the cathodic EC compound undergoes a coloring reaction on the electrode covered with the peripheral sealing seal 12 with a film thickness of about 100 [nm] on the surface. The location of the perimeter seal seal boundary 16 is determined by direct observation of the electrode surface using, for example, a scanning electron microscope.

FIG. 9 shows a view of the electrode surface in the vicinity of the peripheral sealing seal 12 obtained by cutting the EC element manufactured based on the example described later in the direction perpendicular to the electrode surface. FIG. 9(a) is a schematic diagram showing the positional relationship between the electrode and the peripheral sealing seal 12 at the observation point. In FIG. 9A, the first electrode 11a is the anode electrode and the second electrode 11b is the cathode electrode. FIG. 9B is an image observed with a scanning electron microscope. FIG. 9(c) is the same image as FIG. 9(b) superimposed to clearly show the position of the peripheral sealing seal 12 and the peripheral sealing seal boundary 16. FIG. 9B and 9C, the first electrode 11a (anode electrode) shown in FIG. 9A is removed for observation. 9(c) shows the cut surface of the peripheral sealing seal 12. The shaded area in FIG. A white circle at the end of the cut surface of the peripheral sealing seal 12 is the boundary between the peripheral sealing seal 12 and the electrode surface, and corresponds to the peripheral sealing seal boundary 16 in FIG. Thus, by directly observing the location of the peripheral sealing seal boundary 16, the area S _A defined by the peripheral sealing seal 12 of the anode electrode 11a and the area S A defined by the peripheral sealing seal 12 of the cathode electrode 11b. can determine the area S _C .

In addition, when a hole such as an opening is provided in the area on the electrode surface surrounded by the peripheral sealing seal boundary 16 and the electrode does not exist in the opening portion, the area defined by the peripheral sealing seal 12 It is preferable to directly observe the boundary of the peripheral sealing seal 12 as a method of defining S _A and S _C . In such a case, it is specified as follows. If the total area of the openings formed in the upper and lower substrates is 1/10 or less of the area of the smaller one of S _A and S _C , the area of the openings is also included in the area of the electrode. In the area of the opening, there are no electrodes on the side on which the opening is provided, only on the opposite side. Therefore, in this region, a coloring reaction occurs only on the side where the electrodes are present when the EC element is driven. That is, when the anode electrode 11a has an opening, only the cathodic EC compound is colored. When the cathode electrode 11b is provided with an opening, only the anodic EC compound is colored. Here, when the EC device is driven, both electrodes of the anode and the cathode form an electrically closed circuit, so that the amounts of the colored substances of both compounds are basically equal in the entire device. Therefore, in order to compensate for the imbalance of the colored bodies generated in the opening, a region is generated around the opening where the other colored body is preferentially colored. Here, the inventors conducted a series of experiments and found that when the area of the opening is 1/10 or less of the smaller area of S _A and S _C , the It was confirmed that the influence of color unevenness on the color unevenness that occurs in the vicinity of the peripheral sealing seal is small. Therefore, in this specification, which is intended for color unevenness caused by the peripheral sealing seal 12, the area of the opening that satisfies the above requirements is included as the area of the electrode, and the size relationship of the area of the electrode is compared. do.

<Method for electrochemical regulation>
In the electrochemical reaction that causes the coloring reaction of the EC compound, a method for defining the size of the electrode area will be described using the fact that the amount of current and the amount of charge are proportional to the electrode area. First, an EC solution containing an anodic EC compound, a cathodic EC compound, and a solvent is prepared. The EC solution is subjected to conditions in which either the anodic EC compound or the cathodic EC compound reacts much more favorably than the other EC compound. For example, the concentration of the anodic EC compound is ten times the concentration of the cathodic EC compound, thereby making the reaction of the anodic EC compound much more favorable than the reaction of the cathodic EC compound. be done. When this EC solution is used as the EC layer 13, the limiting factor for the current flowing through the device becomes the reaction of the polar EC compound, which is much less reactive. (In the example case, the reaction of the cathodic EC compound at a concentration ten times lower is the current limiting factor.) Therefore, the polarity of the electrode reaction that causes this limiting reaction limits the current in the device. Become. Here, when the voltage applied to the first electrode 11a and the second electrode 11b is constant and the polarity is reversed to color the EC element, the amount of current is proportional to the electrode area, so the current flowing through the element is It will be proportional to the area of the electrode on the side where the limiting reaction occurs. In the case given as an example, when the first electrode 11a is used as the cathode and when the second electrode 11b is used as the cathode, the respective currents are compared, and the area of the electrode through which the larger current flows is larger than the area of the other electrode. In this way, it is possible to define the size relationship between the area S _A defined by the peripheral sealing seal of the anode electrode and the area S _C defined by the peripheral sealing seal of the cathode electrode.

<<Control of the electrode area defined by the peripheral sealing seal 12>>
The magnitude relationship between S _A and S _C can be controlled, for example, by changing the heat conditions applied to the electrodes after the peripheral sealing seal 12 is applied to one of the electrodes during manufacture of the EC device. Thermal conditions include, for example, the temperature of the electrode and the time the electrode is maintained at that temperature. The optimum thermal conditions for realizing the appropriate magnitude relationship between S _A and S _C indicated in this specification will vary depending on the constituents of the perimeter sealing seal and curing conditions. For example, with a peripheral sealing seal that contains a large amount of solvent during application, if the temperature applied after application is lowered, the time required for the solvent to volatilize will be longer. It will spread due to Thus, when the temperature applied after application is low, less area is defined by the peripheral sealing seal on the electrode on the application side than when the temperature is high.

≪Method for solving color unevenness caused by peripheral sealing seals≫
As described above, during coloring, the amounts of the anodic EC compound colored body and the cathodic EC compound colored body are equal in the entire device. In the color unevenness caused by the peripheral sealing seal 12, the imbalance of the colored body generated in the peripheral sealing seal near vicinity 13b is compensated in the peripheral sealing seal closest vicinity 13a, and the above conditions are satisfied. Therefore, the inventors of the present invention have proposed to reduce the imbalance of the colored bodies in the semi-neighborhood 13b of the peripheral sealing seal by preventing the compensation of the imbalance of the colored bodies in the closest vicinity 13a of the peripheral sealing seal, thereby reducing the color unevenness. devised. Specific solutions will be described below for the case where the peripheral sealing seal 12 is an anode-preferential peripheral sealing seal and the case where it is a cathode-preferential peripheral sealing seal.

<When the peripheral sealing seal 12 is an anode preferential peripheral sealing seal>
When the peripheral sealing seal 12 is the anode preferential peripheral sealing seal, the area S _A defined by the peripheral sealing seal 12 of the anode electrode 11a and the area S _C defined by the peripheral sealing seal 12 of the cathode electrode 11b , S _A <S _C . Preferably, S _A <S _C and S _C <2S _A . More preferably, S _A <S _C <2S _A and S _C −S _A ≧200 [μm]×L _C . Here, L _C is the length [μm] of the peripheral seal boundary 16 on the cathode electrode 11b. These reasons are as follows.

[S _A <S _C ]
With this condition, the area covered by the peripheral sealing seal 12 on the anode electrode 11a at the peripheral sealing seal nearest neighbor 13a is larger than the area covered by the peripheral sealing seal 12 on the opposing cathode electrode 11b. . As a result, the coloring reaction of the anodic EC compound is more inhibited in the vicinity 13a of the peripheral sealing seal than when S _A ≧S _C . As described above, preferential coloring of the cathodic EC compound in the semi-neighborhood 13b of the peripheral sealing seal is reduced, and color unevenness is reduced. Therefore, S _A <S _C is more effective in reducing color unevenness than S _C =S _A even if the difference is small.

[S _C <2S _A ]
When S _A <S _C , a region (hereinafter referred to as “region 1”) where there is a peripheral sealing seal 12 coating on the anode electrode 11a but no peripheral sealing seal 12 coating on the opposing cathode electrode 11b ) is equal to S _C −S _A , which is the difference between S _C and S _A . In region 1, when the EC element is driven, a coloring reaction occurs only on the cathode electrode 11b, and as a result, only a colored body of the cathodic EC compound is produced. Here, when the EC device is driven, both the anode and cathode electrodes form an electrically closed circuit, so that the amounts of both the anodic and cathodic compound colored substances are basically equal in the entire device. Therefore, in order to compensate for the imbalance of the colored bodies generated in this region, the anode preferentially colored region (hereinafter sometimes referred to as "region 2") in which the colored bodies of the anodic EC compound are preferentially generated outside the region 1 there is) will occur. As a result of a series of experiments conducted by the present inventors, it was confirmed that the two regions (region 1 and region 2) having a relationship of compensating for the imbalance have approximately the same area. Now, the area of the region where both electrodes are not covered with the peripheral sealing seal (hereinafter sometimes referred to as "region 3") is equal to S _A , which has the smaller area among S _C and S _A . Therefore, when S _C −S _A <S _A , the area of the anode preferentially colored region (region 2) is smaller than the region (region 3) where both electrodes are not coated with the peripheral sealing seal, and the EC element passes through. It is preferable from the viewpoint of the color reproducibility of the image to be printed. The above discussion yields the above conditions.

[S _C -S _A ≧200 [μm]×L _C ]
In a series of experiments conducted by the present inventors, the region of the peripheral sealing seal nearest neighbor 13a is located from the peripheral sealing seal boundary 16 on the electrode (cathode electrode 11b) with the larger area defined by the peripheral sealing seal 12. It was confirmed that it exists with a width of about 200 [μm] toward the inside of the EC layer 13 . Therefore, if the length of the peripheral sealing seal boundary 16 on the cathode electrode is L _C [μm], the area of the nearest peripheral sealing seal 13a is at most 200 [μm]×L _C . Therefore, when S _C −S _A ≧200 [μm]×L _C , the entire preferential coloring of the anodic EC compound occurring in the vicinity 13a of the peripheral sealing seal can be inhibited. It is preferable for the purpose of reduction.

<When the peripheral sealing seal 12 is a cathode preferential peripheral sealing seal>
When the peripheral sealing seal 12 is a cathode preferential peripheral sealing seal, the area S _C defined by the peripheral sealing seal 12 of the cathode electrode 11b and the area S _A defined by the peripheral sealing seal 12 of the anode electrode 11a , S _C <S _A . Preferably, S _C <S _A and S _A <2S _C . More preferably, S _C <S _A <2S _C and S _A −S _C ≧200 [μm]×L _A . Here, L _A is the length [μm] of the peripheral seal boundary 16 on the anode electrode 11a. These reasons are as follows.

[S _C <S _A ]
With this condition, the area covered by the peripheral sealing seal 12 on the cathode electrode 11b at the peripheral sealing seal nearest neighbor 13a is larger than the area covered by the peripheral sealing seal 12 on the opposing anode electrode 11a. . As a result, the coloring reaction of the cathodic EC compound is more inhibited in the vicinity 13a of the peripheral sealing seal than when S _C ≧S _A . As described above, preferential coloring of the anodic EC compound in the semi-neighborhood 13b of the peripheral sealing seal is reduced, and color unevenness is reduced. Therefore, S _C <S _A is more effective in reducing color unevenness than S _C =S _A even if the difference is small.

[S _A <2S _C ]
When S _C < _SA , a region (hereinafter referred to as “region 4”) where there is a peripheral sealing seal 12 coating on the cathode electrode 11b but no peripheral sealing seal 12 coating on the opposing anode electrode 11a ) is equal to S _A −S _C , which is the difference between S _A and S _C . In region 4, when the EC element is driven, a coloring reaction occurs only on the anode electrode 11a, and as a result, only a colored body of the anodic EC compound is produced. Here, when the EC device is driven, both the anode and cathode electrodes form an electrically closed circuit, so that the amounts of both the anodic and cathodic compound colored substances are basically equal in the entire device. Therefore, in order to compensate for the imbalance of the colored bodies generated in this region, a cathodic preferentially colored region (hereinafter sometimes referred to as "region 5") in which the colored bodies of the cathodic EC compound are preferentially generated outside the region 4 is used. there is) will occur. A series of experiments conducted by the inventors of the present invention confirmed that the two regions (region 4 and region 5) in relation to compensation for imbalance have approximately the same area. Now, the area of _the region where both electrodes are not covered with the peripheral sealing seal (hereinafter sometimes referred to as "region 6") is equal to the smaller area of S _C and S _A . Therefore, when S _A −S _C <S _C , the cathode preferentially colored region (region 5) has a smaller area than the region (region 6) where both electrodes are not covered by the peripheral sealing seal, and the EC element passes through. It is preferable from the viewpoint of the color reproducibility of the image to be printed. The above discussion yields the above conditions.

[S _A −S _C ≧200 [μm]×L _A ]
As described above, the region 13a closest to the peripheral sealing seal extends from the peripheral sealing seal boundary 16 on the electrode (anode electrode 11a) with the larger area defined by the peripheral sealing seal 12 to the inside of the EC layer 13. It exists with a width of about 200 [μm]. Therefore, if the length of the peripheral sealing seal boundary 16 on the anode electrode is L _A [μm], the area of the nearest peripheral sealing seal 13a is at most 200 [μm]× _LA . Therefore, when S _A −S _C ≧200 [μm]×L _A , the entire preferential coloring of the anodic EC compound occurring in the vicinity 13a of the peripheral sealing seal can be inhibited. It is preferable for the purpose of reduction.

Incidentally, when a difference is provided in the areas of both electrodes partitioned by the peripheral sealing seal 12 as in the present invention, the degree of color unevenness changes according to the polarity of the voltage applied from the outside when the EC element is driven. This is because the polarity reversal causes the anode and cathode electrodes to be interchanged, and the size relationship between the areas of the anode and cathode electrodes is reversed from that before the reversal. Specifically, when the peripheral sealing seal 12 is an anode preferential peripheral sealing seal and S _A <S _C , the reversal of polarity worsens the degree of color unevenness. This is because S _C < _SA due to the reversal of the polarity, and the size relationship of the area after the reversal is reversed from the size relationship of the area of the present invention. Further, when the peripheral sealing seal is a cathode-preferred peripheral sealing seal and S _C <S _A , the degree of color unevenness is aggravated by the reversal of the polarity. This is because S _A <S _C due to the reversal of the polarity, and in this case also, the size relationship of the areas after the inversion is reversed from the size relationship of the areas of the present invention.

<<Evaluation method of color unevenness>>
A method for evaluating color unevenness, which is color non-uniformity within the element, will be described with reference to FIG. FIG. 10(a) shows the components of the evaluation system and their arrangement. FIG. 10(b) is a diagram schematically showing the relationship between the obtained image and the analysis area.

A plane illuminator 21 and an imaging device 22 are arranged with respect to the transmissive EC element 1 so that the optical axis is perpendicular to the element surface. Images are acquired over time for 24 hours immediately after the EC device 1 is driven. In the image, the area surrounded by the peripheral sealing seal 12 is approximated to a rectangular area 24 having the maximum area, and the rectangular area determined by the following four conditions is analyzed for the rectangular area 24, which will be described later. Region 25 is defined.
(i) 0.8 times the long side (ii) 0.74 times the short side (iii) the center of gravity matches (iv) the long side is parallel to the long side of the original rectangle

A reference RGB value was obtained by averaging the R, B, and G values of all pixels included in the analysis area 25 . Furthermore, the analysis area 25 was divided into a total of 256 rectangular areas of 16 vertical×16 horizontal, and the color difference ΔE ₀₀ between the average RGB value and the reference RGB value in each area was calculated using the color difference formula based on the definition of CIEDE2000. Note that the CIEDE 2000 color difference formula is based on Sharma, Gaurav; Wu, Wencheng; Dalal, Edul N.; See "The CIEDE 2000 color-difference formula: Implementation notes, supplementary test data, and mathematical observations" Color Research & Applications 30(1), 21-30 (2005). The maximum value of the color differences ΔE ₀₀ obtained at each point was taken as the absolute value of color unevenness at each time.

Applications of the EC element 1 according to this embodiment include display devices, variable reflectance mirrors, variable transmission windows, optical filters, and the like. If color unevenness occurs in these applications, the color balance of transmitted light or reflected light changes unintentionally at each point on the EC element surface, which is undesirable in any application.

As an example of this ΔE ₀₀ value, consider the case where this EC element is used as an optical filter of a camera, especially as an ND filter. If color unevenness occurs in the EC element used as the ND filter, the color will change at each point of the image obtained by imaging. Specifically, when the peripheral sealing seal 12 used in the EC device is an anode-preferential peripheral sealing seal, the region of the peripheral sealing seal quasi-neighborhood 13b is colored with a cathodic EC compound (typically green to blue) appears strongly. On the other hand, when the peripheral sealing seal 12 used in the EC element is a cathode preferential peripheral sealing seal, the anodic EC compound is colored (typically red) in the region near the peripheral sealing seal 13b. appear strongly. Accordingly, if the degree of color unevenness caused by the peripheral sealing seal 12 is large, the quality of the obtained image is significantly degraded, which is not preferable.

Thus, when the EC element is used for applications such as optical filters, it is required that the degree of color unevenness be reduced. Specifically, the color difference ΔE ₀₀ is preferably 3.2 or less. The reason for this is that, in general, when the color difference between two colors is 3.2 or less, the two colors are judged to be the same color by human visual confirmation. That is, even when the EC element is used as an optical filter, it is important to satisfy the condition that the maximum value of ΔE ₀₀ in the plane is 3.2 or less in order to maintain the quality of the acquired image. As a result, for example, it is possible to reduce the appearance of objects appearing greener or reddish in the peripheral portion of the screen than in the central portion.

<<Effects of the present invention>>
In the present invention, an EC layer 13 containing an anodic EC compound and a cathodic EC compound is disposed in a space defined by two opposing electrodes 11a, 11b and a peripheral sealing seal 12, and the EC compound is Complementary EC devices that undergo oxidation-reduction reactions are targeted. In this EC device, one of the anodic EC compound and the cathodic EC compound is preferentially colored in the vicinity of the peripheral sealing seal 12 during operation, and color unevenness may occur within the device surface. From the viewpoint of responsiveness and optical density, it is required to increase the concentration of the EC compound. compound and the concentration of the cathodic EC compound) increases. In the present invention, by controlling the magnitude relationship between S _A and S _C , it is possible to reduce color unevenness caused by the peripheral sealing seal 12 even when the concentration of the EC compound is increased.

<<Optical filters, lens units, imaging devices>>
The EC element 1 can be used for optical filters. An optical filter according to another embodiment of the invention has an EC element 1 and an active element connected to the EC element 1 . The active element is an element that adjusts the amount of light transmitted through the EC element, and specifically includes a switching element for controlling the transmittance of the EC element. Examples of switching elements include TFTs and MIM elements. A TFT is also called a thin film transistor, and a semiconductor or an oxide semiconductor is used as its constituent material. Specifically, amorphous silicon, low-temperature polysilicon, semiconductors having InGaZnO as constituent materials, and the like can be mentioned.

The EC element 1 can be used for imaging devices and lens units. An imaging device according to another embodiment of the present invention has the above-described optical filter having an EC element, and a light receiving element 110 that receives light that has passed through the optical filter.

A lens unit according to another embodiment of the present invention includes the above optical filter having an EC element and an imaging optical system. The imaging optical system is preferably a lens group having a plurality of lenses. The optical filter may be arranged so that light that has passed through the optical filter passes through the imaging optical system, or may be arranged so that light that has passed through the imaging optical system passes through the optical filter. Also, the optical filter may be arranged between a plurality of lenses. The optical filter is preferably provided on the optical axis of the lens. The optical filter can adjust the amount of light passing through or passing through the imaging optical system.

FIG. 11 is a diagram schematically showing an example of an imaging device and a lens unit using optical filters. 11(a) shows an imaging apparatus having a lens unit 102 using an optical filter 101, and FIG. 11(b) shows an imaging apparatus having the optical filter 101. FIG. As shown in FIG. 11A, the lens unit 102 is detachably connected to the imaging unit 103 via a mount member (not shown).

A lens unit 102 is a unit having a plurality of lenses or lens groups. For example, in FIG. 11(a), the lens unit 102 represents a rear-focusing zoom lens that performs focusing after the aperture. The lens unit 102 includes, in order from the object side (left side as viewed from the drawing), a first lens group 104 with positive refractive power, a second lens group 105 with negative refractive power, and a third lens group 106 with positive refractive power. , the fourth lens group 107 of positive refractive power. A distance between the second lens group 105 and the third lens group 106 is changed to perform zooming, and a part of the fourth lens group 107 is moved to perform focusing. The lens unit 102 has, for example, an aperture stop 108 between the second lens group 105 and the third lens group 106, and an optical filter between the third lens group 106 and the fourth lens group 107. 101. Light passing through the lens unit 102 is arranged to pass through the lens groups 104 to 107, the aperture stop 108 and the optical filter 101, and the light amount can be adjusted using the aperture stop 108 and the optical filter 101. .

Also, the configuration inside the lens unit 102 can be changed as appropriate. For example, the optical filter 101 can be placed in front of the aperture stop 108 (object side) or behind it (imaging unit 103 side). It may be arranged after 107 . By arranging it at a position where light converges, there is an advantage that the area of the optical filter 101 can be reduced. In addition, the form of the lens unit 102 can also be appropriately selected, and in addition to the rear focus type, it may be an inner focus type in which focusing is performed in front of the diaphragm, or may be another type. In addition to the zoom lens, special lenses such as a fisheye lens and a macro lens can be selected as appropriate.

The imaging unit 103 has a glass block 109 and a light receiving element 110 . A glass block 109 is a glass block such as a low-pass filter, a face plate, or a color filter. Also, the light receiving element 110 is a sensor section that receives light that has passed through the lens unit 102, and can use an imaging element such as a CCD or CMOS. Also, an optical sensor such as a photodiode may be used, and a device that acquires and outputs information on the intensity or wavelength of light can be used as appropriate.

As shown in FIG. 11A, when the optical filter 101 is incorporated in the lens unit 102, driving means such as an active element may be arranged inside the lens unit 102, or may be arranged outside the lens unit 102. good. When arranged outside the lens unit 102, the EC elements inside and outside the lens unit 102 are connected to the driving means through wiring to control driving.

As shown in FIG. 11B, the imaging device itself may have an optical filter 101 . The optical filter 101 may be arranged at an appropriate location inside the imaging unit 103 and the light receiving element 110 may be arranged so as to receive the light that has passed through the optical filter 101 . In FIG. 11B, for example, the optical filter 101 is arranged immediately before the light receiving element 110 . When the imaging device itself incorporates the optical filter 101, the connected lens unit 102 itself does not need to have the optical filter 101, so it is possible to configure a dimming imaging device using an existing lens unit. becomes.

Such an imaging device can be applied to products having a combination of light amount adjustment and light receiving element. For example, it can be used for cameras, digital cameras, video cameras, and digital video cameras, and can also be applied to products with built-in imaging devices, such as mobile phones, smart phones, PCs, and tablets.

By using the optical filter according to this embodiment as a light control member, it is possible to appropriately vary the amount of light control with one filter, and there are advantages such as a reduction in the number of components and a space saving.

According to the optical filter, the lens unit, and the imaging device of this embodiment, it is possible to reduce color unevenness caused by the peripheral sealing seal in the EC element. Therefore, it is possible to reduce deterioration in quality of an image obtained by imaging light transmitted or reflected by the optical filter.

≪Window materials≫
A window material according to another embodiment of the present invention has an EC element 1 and an active element connected to the EC element. 12A and 12B are diagrams schematically showing an example of the window material according to the present embodiment, FIG. 12A being a perspective view, and FIG. be.

A window material 111 in FIG. 12 is a light control window, and is composed of the EC element 1, a transparent plate 113 (a pair of substrates) sandwiching the EC element 1, and a frame 112 surrounding and integrating the whole. The active element is an element that adjusts the amount of light that passes through the EC element 1, and may be directly connected to the EC element 1 or indirectly. Also, the active element may be integrated within the frame 112, or may be arranged outside the frame 112 and connected to the EC element 1 through wiring.

The transparent plate 113 is not particularly limited as long as it is made of a material having a high light transmittance, and is preferably made of a glass material in consideration of its use as a window. In FIG. 12, the EC element 1 is a component independent of the transparent plate 113, but the substrate 10 of the EC element 1 may be regarded as the transparent plate 113, for example.

The frame 112 may be made of any material, but any frame that covers at least a portion of the EC element 1 and has an integrated form may be regarded as the frame.

Such a light control window can also be called a window material having an electronic curtain. When the EC element 1 is in a decolored state, a sufficient amount of transmitted light can be obtained with respect to incident light. Modulated optical properties are obtained. The window material according to the present embodiment can be applied, for example, to adjust the amount of sunlight entering a room during the day. Since it can be applied not only to the amount of sunlight but also to the adjustment of the amount of heat, it can be used to control indoor brightness and temperature. It can also be used as a shutter to block the view from the outside to the inside. Such dimming windows can be applied not only to glass windows for buildings, but also to windows of vehicles such as automobiles, trains, airplanes, and ships, and to filters for display screens of clocks and mobile phones.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

<<Production of EC element>>
An EC device having the structure shown in FIG. 1 was produced by the following method.
Two transparent conductive glass substrates (10a, 10b) having indium-doped tin oxide (ITO) films (electrodes 11a, 11b) formed thereon were prepared. Two through holes (not shown) were formed in one of the substrates by blasting.

Next, gap control particles (Micropearl SP250 (diameter 50 μm), manufactured by Sekisui Chemical Co., Ltd.) and a thermosetting epoxy resin mixture (Structbond HC-1850, manufactured by Mitsui Chemicals) are kneaded to form a peripheral sealing seal 12. was prepared. Next, an uncured body of the peripheral sealing seal 12 was applied onto the surface of the electrode 11a or 11b using a dispenser device. The application pattern at this time was drawn so that the two through-holes provided in one of the glasses were arranged in the region surrounded by the peripheral sealing seal 12 after the later-described glass bonding process. Next, the substrate coated with the uncured body of the peripheral sealing seal 12 was heated at 90° C. for 10 minutes to volatilize the solvent contained in the uncured body of the peripheral sealing seal 12 . Next, after bonding the substrate coated with the uncured body of the peripheral sealing seal 12 and the other substrate so that the electrodes (11a, 11b) face each other, they are exposed to an environment of 150° C. for 2 hours. Thus, the uncured body of the sealing seal 12 was cured.

A plurality of elements containing no EC solution were prepared in this way, and some of them were cut along a plane perpendicular to the electrode surface, and the electrode surface near the peripheral sealing seal 12 was observed with a scanning electron microscope. FIGS. 9B and 9C show the results. As a result of observation, assuming that the electrode on the side of the substrate coated with the peripheral sealing seal is the cathode electrode and the other electrode is the anode electrode, S _A is 159.48 [mm ² ] and S _C is 160.00 [mm ² ]. It was confirmed that From this, it was confirmed that the difference S _C -S _A between S _C and S _A was 0.52 [mm ² ]. From the above, it was confirmed that S _A <S _C (that the electrode on the side of the substrate to which the peripheral sealing seal is applied has a larger area defined by the peripheral sealing seal). Furthermore, it was also confirmed that the condition of S _C < _2SA was satisfied.

Next, an anodic EC compound (dihydrophenazine derivative) and a cathodic EC compound (viologen derivative) were each dissolved in propylene carbonate to a concentration of 233 [mmol/L] to prepare an EC solution.

Next, in a nitrogen atmosphere, the EC solution was filled into the space defined by the opposing electrodes (11a, 11b) and the peripheral sealing seal 12 through the above-described through-holes to obtain the EC layer 13. Next, an ultraviolet curable acrylic resin (TB3035B manufactured by ThreeBond Co., Ltd.) was applied around the through holes, shaped to close the holes, and cured by UV irradiation. Further, an ultraviolet curable epoxy resin (Photolec E-1220B manufactured by Sekisui Chemical Co., Ltd.) was applied to the same portion and cured by UV irradiation to obtain EC element 1.

≪Evaluation of color unevenness≫
The EC element was arranged so that the element surface was horizontal. Next, as shown in FIG. 10, an imaging device 22 (Canon Eos kiss x5) is placed above the element 1 so that the optical axis is perpendicular to the element surface, and a surface illumination 21 (FUJICOLOR HR- 2) was placed. The EC device was driven by applying a voltage of 0.7 V between the anode and the cathode, and images were acquired at intervals of 30 minutes for 24 hours immediately after driving the EC device. The acquired image was resized to 200px×134px. A reference RGB value was obtained by averaging the R, B, and G values of all pixels included in the analysis area 25 of the image. Furthermore, the analysis area 25 is divided into a total of 256 rectangular areas of 16 vertical × 16 horizontal, and the color difference ΔE ₀₀ between the average RGB value and the reference RGB value in each area is calculated using the color difference formula based on the CIEDE 2000 definition. Calculated. The maximum value of the color differences ΔE ₀₀ at each point thus obtained was taken as the absolute value of color unevenness at each time, and the absolute value of color unevenness after 24 hours was evaluated.

<<Evaluation result>>
First, the EC element filled with the EC solution is colored by applying a voltage so that the electrode on the substrate side to which the peripheral sealing seal is applied becomes the anode (S _A >S _C ). A color spectrum of the peripheral sealing seal nearest neighbor 13a was obtained. From the shape of the obtained spectrum, it was confirmed that the anodic EC compound was preferentially colored in the vicinity 13a of the peripheral sealing seal. Furthermore, when the polarity of the voltage applied to the EC element was reversed and the coloring spectrum of the nearest neighbor 13a of the peripheral sealing seal was confirmed again, preferential coloring of the anodic EC compound was confirmed as before the reversal. From the above results, it was confirmed that the perimeter sealing seals of the examples were anode preferential perimeter sealing seals.

FIG. 13 shows the color unevenness under two conditions: when the electrode on the substrate side to which the peripheral sealing seal is applied is used as a cathode electrode (S _A <S _C ) and when it is used as an anode electrode (S _A >S _C ). 4 is a graph showing the results of measuring ΔE ₀₀ as an index. From FIG. 13, it was confirmed that the color difference in the case of S _A <S _C is about 2.8 smaller than that in the case of S _A >S _C , satisfying the condition of ΔE ₀₀ ≦3.2.

The following effects were confirmed from this example.
(A) In a complementary EC device where the peripheral sealing seal 12 is an anode-preferential peripheral sealing seal, color due to the peripheral sealing seal 12 by satisfying S _A < S _C Unevenness can be highly reduced.
(B) An EC element that satisfies S _A <S _C can highly reduce color unevenness caused by the peripheral sealing seal 12 even when the concentration of the EC compound is higher than 0.1 mol/L.

A similar effect can be confirmed even in an EC device in which the peripheral sealing seal 12 is a cathode-preferred peripheral sealing seal.

1: EC element, 10a: first substrate, 10b: second substrate, 11a: first electrode, 11b: second electrode, 12: peripheral sealing seal, 13: EC layer, 13a: peripheral sealing 13b: Quasi-near the peripheral sealing seal; 14: Rectangular area; 15: Element central part; 16: Peripheral sealing seal boundary

Claims (14)

a first electrode;
a second electrode;
a peripheral sealing seal positioned between the first electrode and the second electrode;
an electrochromic layer disposed in a space defined by the first electrode, the second electrode, and the peripheral sealing seal;
one of the first electrode and the second electrode is an anode electrode and the other is a cathode electrode;
An electrochromic device, wherein the electrochromic layer comprises an anodic electrochromic compound and a cathodic electrochromic compound,
the peripheral sealing seal is an anodic preferential peripheral sealing seal that preferentially oxidizes an anodic electrochromic compound in the vicinity of the peripheral sealing seal;
An electrochromic device characterized in that S _A <S _C .
S _A : area defined by the peripheral sealing seal of the anode electrode _SC : area defined by the peripheral sealing seal of the cathode electrode 2. The electrochromic device of claim 1, wherein S _C <2S _A . 3. The electrochromic device according to claim 2, wherein S _C −S _A ≧200 [μm]×L _C .
L _C [μm]: length of the boundary of the peripheral sealing seal on the cathode electrode a first electrode;
a second electrode;
a peripheral sealing seal positioned between the first electrode and the second electrode;
an electrochromic layer disposed in a space defined by the first electrode, the second electrode, and the peripheral sealing seal;
one of the first electrode and the second electrode is an anode electrode and the other is a cathode electrode;
An electrochromic device, wherein the electrochromic layer comprises an anodic electrochromic compound and a cathodic electrochromic compound,
The peripheral sealing seal is a cathodic preferential peripheral sealing seal that prioritizes the reduction reaction of the cathodic electrochromic compound in the vicinity of the peripheral sealing seal,
An electrochromic device characterized in that S _C < _SA .
S _A : area defined by the peripheral sealing seal of the anode electrode _SC : area defined by the peripheral sealing seal of the cathode electrode 5. The electrochromic device of claim 4, wherein S _A <2S _C . 6. The electrochromic device according to claim 5, wherein S _A −S _C ≧200 [μm]× _LA .
L _A [μm]: length of boundary of the peripheral sealing seal on the anode electrode 7. The sum of the concentration of the anodic electrochromic compound and the concentration of the cathodic electrochromic compound in the electrochromic layer is 0.1 mol/L or more. The electrochromic device according to the paragraph. 8. The sum of the concentration of the anodic electrochromic compound and the concentration of the cathodic electrochromic compound in the electrochromic layer is 0.4 mol/L or more. The electrochromic device according to . 9. The electrochromic device according to any one of claims 1 to 8, wherein the electrochromic layer further contains a solvent. 10. The electrochromic device according to any one of claims 1 to 9, wherein the anodic electrochromic compound and the cathodic electrochromic compound are organic compounds. An optical filter comprising: the electrochromic element according to any one of claims 1 to 10; and an active element connected to said electrochromic element for driving said electrochromic element. A lens unit comprising the optical filter according to claim 11 and an imaging optical system having a plurality of lenses. 12. An imaging apparatus comprising: the optical filter according to claim 11; and a light receiving element for receiving light transmitted through the optical filter. A window material comprising: the electrochromic element according to any one of claims 1 to 10; and an active element connected to the electrochromic element.

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