JP7277110B2 - electrochromic element - Google Patents

Description

The present invention relates to electrochromic devices.

EC elements using electrochromic (hereinafter sometimes abbreviated as "EC") materials that change the optical absorption properties (absorption wavelength, absorbance) of substances due to electrochemical oxidation-reduction reactions It has the feature of being able to achieve both high transmittance in the case of coloring and low transmittance in the case of coloring. Utilizing this feature, it is applied to display devices, variable reflectance mirrors, variable transmission windows, and the like. As a direction of development for increasing the functionality of these applications and expanding the range of applications, developments related to increasing the size of devices are being actively carried out. An EC element is basically a current-driven element whose optical characteristics change when a Faraday current flows due to an electrochemical reaction of an EC material. For this reason, a larger current flows in many cases than in a voltage-driven liquid crystal element, which is often compared. In order to reduce the effect of the voltage drop due to the large current, efforts have been made to reduce the resistance of the EC element. As a method of reducing the element resistance caused by the resistance of the transparent electrodes used in EC elements, bus bars (feeding wires) that apply metal to the outside of the effective optical area of the element (mainly on the substrate) are widely used. . When the size of the EC element is increased, the current per unit area (current density) of the EC element usually does not change. Therefore, it is required to reduce the resistance of the busbar as the current increases.
Since the busbar resistance can be reduced by increasing the cross-sectional area of the busbar, the width and thickness of the busbar can be simply increased. However, the increase in width and thickness imposes limits on the function of the EC device. Increasing the width of the busbar increases the bezel portion (non-effective optical area) which is the peripheral area of the effective optical area of the EC element (the area where the EC element absorbs light to perform its function). . This is not desirable in terms of appearance and function, because it increases the peripheral area of display devices, variable reflectance mirrors, variable transmission windows, etc., which are applications of the EC element, for example. Further, an EC element is often composed of two sheets of electrodes facing each other, and there is a limit to increasing the thickness of the busbar because it causes a short circuit due to contact with the electrodes facing each other. Therefore, it is desired to reduce the resistance of the busbars without increasing the space of the busbars.
US Pat. No. 5,300,005 discloses an electrochromic lens in which a substrate is flanked by busbars having tabs embedded in conductive epoxy. Arranging the busbar on the side surface is effective in avoiding a short circuit with the opposing electrode caused by thickening the busbar.

Japanese Patent Publication No. 2002-507781

However, in the method of Patent Document 1, there is a problem that the bezel portion increases because the side projection occurs.
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and its object is to provide an EC element in which the resistance of the busbars is reduced without increasing the space of the busbars.

The present invention comprises a pair of substrates, a pair of electrodes arranged between the pair of substrates, an electrochromic layer arranged between the pair of electrodes, and an electrochromic layer connected to the pair of electrodes, respectively. an electrochromic device comprising:
Having a partition between the pair of electrodes,
Having a space surrounded by the pair of electrodes and the partition,
Having the bus bar outside the space,
The base material and the electrode have a busbar separation portion that increases the distance between the busbar connected to one of the pair of electrodes and the busbar connected to the other of the pair of electrodes,
The electrochromic device is characterized in that the busbar separation portion is a concave portion provided in the base material and an embedded portion in which the busbar provided in the electrode is embedded.

According to the present invention, it is possible to provide an EC device that achieves both a reduction in busbar resistance and space saving.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic explaining the outline|summary of EC element of 1st Embodiment. It is the schematic which shows the base material used with the EC element of FIG.1(b). 4 is a graph showing the relationship between busbar length and voltage drop. It is the schematic explaining the outline|summary of the EC element of 2nd Embodiment. It is the schematic explaining the outline|summary of the EC element of 3rd Embodiment. FIG. 2 is a schematic diagram illustrating fabrication of an EC element body of Example 1. FIG. 4 is a graph showing the relationship between the length of the busbar and the characteristics of the EC device of Example 1. FIG. FIG. 10 is a schematic diagram for explaining the production of the EC element body of Example 2;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

An electrochromic device according to the present invention comprises a pair of substrates, a pair of electrodes interposed between the pair of substrates, an electrochromic layer interposed between the pair of electrodes, and an electrochromic layer electrically connected to the electrodes. and at least one busbar. Then, the substrate or the electrode is provided with a busbar arrangement portion, and at least part of the busbar is arranged in the arrangement portion. The placement portion provided on the substrate or the electrode may be a recess. A bus bar may be arranged so as to be embedded in the recess.

An electrochromic device according to the present invention comprises a pair of substrates, a pair of electrodes interposed between the pair of substrates, an electrochromic layer interposed between the pair of electrodes, and a pair of and busbars respectively connected to the electrodes. The base material or the electrode has a busbar separation portion that increases the distance between the busbar connected to one of the pair of electrodes and the busbar connected to the other of the pair of electrodes. The busbar spacing portion may be a recess provided in the substrate or the electrode. A bus bar may be arranged so as to be embedded in the recess.

By providing the busbar arrangement portion or the busbar spacing portion, it is possible to suppress short-circuiting between the busbars. Since the short circuit between electrodes is suppressed, the distance between electrodes may be 100 micrometers or less. Furthermore, the inter-electrode distance may be 25 μm or more and 100 μm or less.

<<First embodiment>>
FIG. 1 is a schematic diagram for explaining the outline of an electrochromic device according to a first embodiment of the present invention, and is a cross-sectional view taken along a plane perpendicular to the longitudinal direction of the EC device. FIG. 1(a) shows an EC device for comparison (hereinafter sometimes referred to as a “comparative device”), and FIG. 1(b) shows the EC device of this embodiment. FIG. 2 is a schematic diagram showing the substrate used in the EC device of FIG. 1(b), FIG. 2(a) is a top view, and FIG. It is a diagram.

In FIG. 1, an EC device 100 has a pair of opposing electrodes 101, at least one of which is transparent, for coloring and decoloring the device. The electrode 101 is preferably arranged on a pair of facing substrates 102, at least one of which is transparent. In the space between the electrodes 101, an electrochromic layer 103 whose light transmittance is changed by voltage application is arranged, and the EC layer 103 is isolated from the outside by a partition wall 104 as necessary.

The EC device 100 of the present embodiment has at least one bus bar (feeder wire) 105 electrically connected to the electrodes 101 and for applying a drive voltage to the electrodes 101 . The basic role of the bus bar 105 is to assist the electrical conduction of the electrode 101 (especially the transparent electrode), which has a higher resistance value than metal, to make the potential distribution in the electrode 101 uniform. Therefore, the electrical resistance of bus bar 105 is preferably smaller than the electrical resistance of electrode 101 . As shown in FIG. 2(a), the bus bar 105 has a length L, a width W, and a thickness t. It is preferable to arrange them along the horizontal direction in FIG. 2(a). Moreover, as shown in FIG. 2B, the bus bar 105 is preferably embedded in the electrode 101 and the substrate 102 . Arranging the busbars 105 as shown in FIG. 2B can also be said to arrange the busbars in the busbar arrangement portions or the busbar separation portions, preferably recesses, provided in the electrode 101 and the substrate 102.

Generally, the resistance of a conductor having three-dimensional conductivity is represented by Equation (1).
R=ρL/A=ρL/Wt (1)
(R: resistance, ρ: resistivity of conductor, L: length of conductor, A: cross-sectional area of conductor, W: width of conductor, t: thickness of conductor)

Here, an EC element having a drive current density of I, a longitudinal length of the bus bar 105 of L, and a unit width (width=1) is assumed. At this time, the voltage drop in busbar 105 is given by the product of the resistance of busbar 105 and the current flowing through busbar 105, and is expressed by equation (2).
ΔV=ILR=(IρL ² )/Wt (2)

FIG. 3 shows the relationship between the length L of the busbar 105 of the EC element 100 and the voltage drop ΔV when the thickness t of the busbar 105 is changed. In FIG. 3, ρ=5×10 ⁻⁵ Ωcm, W=0.2 cm, and I=5.5 mA cm ⁻² are assumed. From this, assuming that the resistivity of the busbar 105 is constant, when the length of the busbar 105 (the length of the EC element 100 in this embodiment) L is changed by n times, the voltage drop in the busbar 105 is n ² times. It is confirmed that In other words, in order to keep the voltage drop in the busbar 105 constant, it is necessary to increase the cross-sectional area (thickness t×width W) of the plane perpendicular to the longitudinal direction of the busbar 105 by n ² times. . Thus, in order to maintain the characteristics even in an enlarged device, the cross-sectional area of the bus bar 105 must increase quadratically with respect to the length of the device. On the other hand, from a practical point of view, the area of the bezel portion 106 of the non-effective optical region, which is the peripheral region of the effective optical region of the EC device 100 (the region that absorbs light to exhibit the device function), the ratio to the entire device, and the electrode There are constraints on the spacing of busbars 105 such as the distance between 101 . In the present embodiment, at least part of the bus bar 105 is embedded in the base material 102 or the electrode 101 in order to achieve both of these.

That is, in the comparative element, the bus bar 105 is formed on the electrode 101 as shown in FIG. 1(a), but in the EC element 100 of the present embodiment, as shown in FIG. is embedded in the electrode 101 and the substrate 102 . Thereby, the thickness t of the busbars 105 can be increased while maintaining the gap 110 between the busbars 105 as compared with the comparative element. Therefore, the cross-sectional area of the bus bar 105 can be increased without increasing the width W of the bus bar 105 as compared with the comparative element. As a result, the resistance of the bus bar 105 can be reduced while maintaining or reducing the width of the bezel portion 106 of the EC element 100 as compared with the comparative element. By reducing the width of the bezel portion 106, the effective optical area of the device can be increased. As a result, it is possible to provide, for example, an EC element with a compact overall size and an EC element with an excellent appearance. Furthermore, the distance between the two electrodes 101 can be shortened by making the height of the portion of the bus bar 105 protruding from the surface of the electrode 101 lower than that of the comparative element. As a result, the degree of freedom in designing the thickness of the EC layer 103 can be increased. Specifically, by reducing the inter-electrode distance (the thickness of the EC layer 103), it is possible to improve the response speed and control the concentration.

The material of the bus bar 105 is not particularly limited as long as it has a high conductivity per unit volume. Basically, metal materials are used, and silver, copper, aluminum, etc. are preferably used among them. A method for forming the bus bar 105 of the present embodiment can be selected without particular limitation. As an example, there is a method of preparing the base material 102 that has been dug in advance, and then forming the bus bar 105 . A method for engraving the base material 102 can be selected according to the material of the base material 102 . For example, if the base material 102 is glass, techniques such as laser processing, etching, ultrasonic processing, and grinding can be used. A method for forming the busbar 105 can be selected according to the materials of both the busbar 105 and the base material 102 . Specifically, methods such as printing using metal paste, sputtering, and plating can be used. In addition to these forming methods, it is preferable to form the bus bar 105 in a desired shape by using techniques such as patterning and polishing.

Each component shown in FIGS. 1 and 2 will be specifically described below.
The EC element 100 is an element that can electrically change the amount of light absorption. The EC element 100 may be of any type such as a transmissive type, a reflective type, or a light scattering type. EC elements 100 include those using inorganic materials and those using organic materials, and those using organic materials include those using high-molecular-weight organic materials and low-molecular-weight organic materials. Any element can be used as the EC element 100 of the present embodiment. From the viewpoint of contrast and maximum transmittance, an EC device using a low-molecular-weight organic material is preferably used. Although the control range of the light absorptance of the EC element 100 is not particularly limited, it is desirable to secure a range that satisfies the performance of applications such as anti-glare mirrors and light control windows. As a specific numerical value, a value of 0% to 99.999% is ideally mentioned, and a value of 1% to 99.9% is practically mentioned. As for the control of the light absorptance between them, it is possible to control only ON/OFF, but it is preferable to be able to control with a plurality of gradations or stepless gradation.

A light-transmissive base material is used as the base material 102 . Here, the term "light transmissive" means that the corresponding base material, electrodes, etc. transmit light, and that the transmittance is 50% or more and 100% or less. Specifically, glass, a polymer compound, or the like is used, and an antireflection coating or the like is applied as necessary.

As the material of the electrode 101 formed on the base material 102, a material having transparency and conductivity and having stability upon reaction of the EC material can be preferably used. For example, transparent conductive oxide electrodes such as indium tin oxide (ITO) and fluorine-doped tin oxide are preferably used. In addition, other conductive materials such as carbon nanotubes or the like, in which a thin metal wire or thin film is arranged to reduce the resistance value, may be used. When the EC element 100 is of a reflective type, a light-reflective electrode may be used as the electrode 101 behind the optical path. Specifically, metals, particularly electrochemically stable noble metals, can be used. In this case, an electrode that does not transmit light may be used instead of the light-transmitting electrode. Specifically, metal can be used.

A material exhibiting EC properties is used for the EC layer 103 . The EC layer 103 may be a solid EC layer formed by depositing an EC material on the electrode 101, or may be a solution EC layer formed by dissolving an EC material in a solvent. Examples of materials used for the EC layer 103 include the following. Inorganic EC materials such as tungsten oxide and iridium oxide for inorganic EC elements, polymer organic EC materials such as polythiophene and polyaniline for organic polymer EC elements, and organic low-molecular-weight EC elements are shown below. Organic small molecule EC materials are used. Examples of organic low-molecular-weight EC materials include pyridine salt derivatives, aromatic amine compounds, and heterocyclic compound derivatives, and these may be used in a state of being dissolved in a solvent. The solvent is selected depending on the application in consideration of the solubility, vapor pressure, viscosity, potential window, etc. of solutes including EC materials, but a polar solvent is preferable. Specifically, methanol, ethanol, propylene carbonate, ethylene carbonate, dimethylsulfoxide, dimethoxyethane, γ-butyrolactone, γ-valerolactone, sulfolane, dimethylformamide, dimethoxyethane, tetrahydrofuran, acetonitrile, propionitrile, benzonitrile, dimethylacetamide. , methylpyrrolidinone, dioxolane and other organic polar solvents and water. In addition, the EC layer 103 may contain an electrolyte, a viscosity modifier, a UV stabilizer, etc., if necessary. The viscosity modifier may increase or decrease the viscosity of the EC layer 103, but preferably increases the viscosity. Increasing the viscosity of the EC layer 103 is advantageous when the area of the light transmitting surface of the EC element 100 is increased, that is, for increasing the area.

A partition wall 104 is preferably used to hold the EC layer 103 between the two electrodes 101 and to keep the distance between both electrodes, and a sealing material is preferably used as the partition wall 104 . As the sealing material, it is preferable to use a material that is chemically stable, hardly permeates gas and liquid, and does not inhibit the redox reaction of the EC material. For example, inorganic materials such as glass frit, organic materials such as epoxy and acrylic resins, and metals can be used. The sealing material may have a function of maintaining the distance between the two electrodes 101 by containing a spacer material or the like. If the sealing material does not have the function of defining the distance between the electrodes 101, a separate spacer may be arranged to maintain the distance between the two electrodes. 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. This spacer can define and maintain the distance between the electrodes 101 constituting the EC element 100 .

<<Second Embodiment>>
FIG. 4 is a schematic diagram for explaining the outline of the EC device according to the second embodiment of the present invention, and is a cross-sectional view taken along the same plane as in FIG. FIG. 4(a) shows the EC device for comparison, and FIGS. 4(b) and 4(c) show the EC device of this embodiment. This embodiment is the same as the first embodiment except that the resistance (cross-sectional area) of the bus bar 105 is the same as that of the comparison element.

In the EC device 100 of this embodiment shown in FIG. 4B, a part of the bus bar 105 having the same thickness t and width W as the bus bar 105 of the comparative device is embedded in the electrode 101 and the substrate 102. . As a result, the distance between the two electrodes 101 can be shortened while maintaining the gap 110 between the busbars 105 and the thickness t of the busbars 105 as compared with the comparative element. As a result, the degree of freedom in designing the thickness of the EC layer 103 can be increased. Specifically, by reducing the inter-electrode distance (the thickness of the EC layer 103), it is possible to improve the response speed and control the concentration.

In addition, in the EC element 100 of the present embodiment shown in FIG. 4(c), a part of the bus bar 105 having the same cross-sectional area but having a larger thickness t than the bus bar 105 of the comparative element is embedded in the electrode 101 and the substrate 102. formed by As a result, the bezel portion 106 can be reduced while maintaining the gap 110 between the busbars 105 and the cross-sectional area of the busbars 105 . As a result, the proportion of the effective optical area in the device can be increased. As a result, it is possible to provide, for example, an EC element with a compact overall size and an EC element with an excellent appearance.

<<Third Embodiment>>
FIG. 5 is a schematic diagram for explaining the outline of an EC device according to a third embodiment of the present invention, and is a cross-sectional view taken along the same plane as in FIG. This embodiment is the same as the first embodiment except that the surface of the bus bar 105 is flush with the surface of the electrode 101 or recessed from the surface of the electrode 101 .

In the EC device 100 shown in FIG. 5A, the busbar 105 is arranged so that the surface of the busbar 105 and the surface of the electrode 101 are flush with each other. In this case, it is possible to prevent the busbars 105 from protruding with respect to the surface of the electrodes 101, thereby preventing the busbars 105 from standing out and improving the appearance. Specifically, it can be seen as if the bus bar 105 does not exist, so that the appearance is neat, and when the surface layer is coated, the difference in level is not conspicuous, and the uniformity of the coating is improved. are mentioned.

In addition, in the EC device 100 shown in FIG. 5B (reference example) , the bus bar 105 is positioned so that the surface of the bus bar 105 is recessed from the surface of the electrode 101 and is flush with the surface of the substrate 102 . are placed in Furthermore, in the EC device 100 shown in FIG. 5B, the electrode 101 is arranged on the bus bar 105. In this case, the degree of freedom in selecting the material for bus bar 105 is improved. Specifically, even a material that reacts with the EC layer 103 at the potential at which the EC layer 103 undergoes a coloring and decoloring reaction when directly in contact with the EC layer 103 can be selected as the material for the bus bar 105 . . Moreover, as shown in FIG. 5B, the bus bar 105 can be arranged in a region overlapping with the effective optical region, which is also preferable in that the bezel portion 106 can be reduced or eliminated. Reducing the size of the bezel portion 106 means that the peripheral portion that is not directly related to the function of the EC element 100 is reduced. , and has the advantage of providing a clean appearance.

≪Applications of electrochromic elements≫
The electrochromic device according to the present invention may be used as an optical filter for imaging devices such as cameras. An imaging device such as a camera may have an optical filter, an imaging optical system having a plurality of lenses, and an imaging device that receives light that has passed through the imaging optical system. The optical filter may have an electrochromic element and an active element connected to the electrochromic element. Examples of active elements include transistors and the like, and the transistors may be used as switching elements or amplifying elements. The optical filter may be arranged immediately before the imaging element of the imaging device or between the lenses of the imaging optical system. Also, the optical filter may be arranged such that the imaging optical system is arranged between the imaging element of the imaging device and the optical filter. In this case, it can also be expressed as the outside of the imaging optical system.

The electrochromic device according to the present invention may be used in electrochromic mirrors used in automobiles and the like. The electrochromic mirror may have a reflective member in addition to the electrodes and the base material. may consist of An electrochromic mirror has an electrochromic element and an active element connected to the electrochromic element. The electrochromic device according to the present invention may be used for windows of automobiles, aircraft and the like. The window has controls for the passengers to change the transmittance.

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.

<<Example 1>>
(1) Fabrication of EC Element Body FIG. 6 is a schematic diagram illustrating fabrication of an EC element body. FIG. 6(a) is a diagram for explaining the production of the EC element body of the example, and FIG. 6(b) is a diagram for explaining the production of the EC element body of the comparative example. It is a diagram. FIG. 6(c) is a top view of the EC element body of the example and the comparative example.

(1a) Fabrication of EC Element Body of Example As shown in FIG. 6(a), an EC element body of Example is fabricated. First, a glass substrate in which grooves 107 (2 mm wide and t μm deep) for busbar formation with a thickness t (=200, 150, 120, 80) μm are formed by a resist forming and etching process is prepared as a substrate 102 . . An indium tin oxide (ITO) film (thickness: 400 nm) is formed as an electrode 101 on the substrate 102 by sputtering to prepare transparent conductive glass. By repeating the printing/curing process of Ag paste on the grooves 107 of the base material 102, the bus bar 105 having a width W=2 mm and a thickness t μm is formed. The resistivity ρ of the bus bar 105 at this time is 5×10 ⁻⁵ Ωcm. After that, as partition walls 104, a UV-curing sealing material mixed with spacer beads of 50 μm is applied. After that, two substrates 102 are superimposed so that the electrodes 101 face each other, and UV light is irradiated to cure the sealing material. Further, a feeder line 109 is connected to one end of the bus bar 105 by ultrasonic soldering. As a result, the two substrates 102 are bonded, the distance between the electrodes is 50 μm, and the effective optical area is 10 mm (the length in the direction perpendicular to the longitudinal direction of the bus bar 105)×200 mm (the direction parallel to the longitudinal direction of the bus bar 105). length) of the EC element body.

(1b) Fabrication of EC Element Body of Comparative Example As shown in FIG. 6B, an EC element body is fabricated in the same manner as in Example except that grooves 107 for forming bus bars are not formed in the substrate 102 . The thickness t of the busbars 105 is 20 μm, and the distance between the opposing busbars 105 is 10 μm.

(2) Injection of Electrolyte Solution An anodic EC compound, 5,10-dimethyl-5,10-dihydrophenazine, and a cathodic EC compound, heptyl viologen trifluoromethanesulfonate, were dissolved in propylene carbonate. Prepare an electrolyte solution. At this time, the concentration of each EC compound contained in the electrolyte solution was 100 mM. Next, after injecting this electrolyte solution from an injection port (not shown) formed in the partition wall 104 into the space 108 to be the EC layer, the EC element is sealed by sealing with the above-mentioned UV-curing sealing material. get

(3) Evaluation A driving voltage of 0.62 V was applied to the EC element, and the distance (L) from the end of the effective optical area of the element on the end side to which the power supply line 109 was attached, the voltage drop, and the decolorization state of the EC element were measured. Measure the change in absorbance (ΔOD) in the colored state. The results are shown in FIG.

FIG. 7(a) shows the relationship between the distance L and the voltage drop when the thickness of the busbar is changed. In the element of the embodiment, even when the distance between the electrodes is limited (the distance between the electrodes is 50 μm in this embodiment), a sufficiently large busbar thickness can be ensured. Therefore, it can be seen that the voltage drop can be greatly suppressed as compared with the element of the comparative example.

FIG. 7(b) shows the relationship between the distance L and the ΔOD of the EC element at a wavelength of 605 nm when the thickness of the busbar is changed. From this, it can be seen that the element of the example can reduce the voltage drop as compared with the element of the comparative example, so that the decrease in ΔOD due to the increase of L can be greatly suppressed. From this, it can be seen that the element of the example is an element having high uniformity of coloring in which good coloring characteristics can be obtained even in the region of L>16 cm where the element of the comparative example is hardly colored.

In summary, it can be said that the following effects can be obtained from this embodiment.
・It is possible to ensure the thickness of the bus bar even in devices where the distance between electrodes and the space of the bezel are limited.
・It is possible to reduce the voltage drop accompanying the enlargement of the device.
・Decrease in ΔOD can be greatly suppressed.
・It is possible to provide an element with high coloring uniformity.

≪Example 2 (reference example) ≫
(1) Fabrication of EC Element Body FIG. 8 is a schematic diagram illustrating fabrication of an EC element body. FIG. 8(a) is a diagram for explaining the manufacturing process of the EC element body of the example, and FIG. 8(b) is a diagram for explaining the manufacturing process of the EC element body of the comparative example. is a cross-sectional view of. FIG. 8(c) is a top view of an EC element body of an example, and FIG. 8(d) is a top view of an EC element body of a comparative example.

(1a) Fabrication of EC Element Body of Example As shown in FIG. 8(a), an EC element body of Example is fabricated. First, a glass substrate is prepared as a substrate 102, in which grooves 107 (width 2 mm, depth 20 μm) for bus bar formation with a thickness of 20 μm are formed by resist formation and etching processes. By repeating the Ag paste printing/curing process on the grooves 107 of the base material 102, the bus bar 105 having a width W of 2 mm and a thickness of 20 μm is formed. The resistivity ρ of the bus bar 105 at this time is 5×10 ⁻⁵ Ωcm. The surface of the bus bar 105 is flattened to be uniform with the surface of the substrate 102 by a polishing process, and an indium tin oxide (ITO) film (400 nm thick) is formed by sputtering to form a transparent conductive electrode as the electrode 101 . After that, as partition walls 104, a UV-curing sealing material mixed with spacer beads of 50 μm is applied. On the other hand, an Ag layer 111 as a lower layer and an ITO layer 112 as an upper layer are formed on another base material 102 by sputtering to form a reflective electrode as the electrode 101 . Two substrates 102 are superimposed on the transparent electrode with the reflective electrode so that the electrodes 101 face each other, and UV light is irradiated to cure the sealing material. Furthermore, the power supply line 109 is connected to both ends of the bus bar 105 by ultrasonic soldering. As a result, the two substrates 102 are bonded together to produce a reflective EC element body having an inter-electrode distance of 50 μm and an effective optical area of 20 mm×20 mm. The distance L ₁ between the busbars 105 at this time is 20 mm.

(1b) Fabrication of EC element body of comparative example As shown in FIG. Thus, an EC element body of a comparative example is produced. The thickness W of the busbars is 20 μm, and the distance L ₀ between the busbars is 24 mm.

(2) Injection of Electrolyte Solution An EC element is obtained by injecting an electrolyte solution into the space 108 and sealing it in the same steps as in Example 1. FIG.

(3) Evaluation Evaluate unevenness of coloring density in the coloring state of the EC element. Specifically, the coloring state of the central portion of the element is compared with the portion in the vicinity of the busbar, which is colored most densely in the coloring region. Specifically, ΔOD is measured when a voltage of 0.62 V is applied to the EC element to color it. Table 1 shows the results.

In the element of the example, the surface of the busbar is arranged so as to be flush with the surface of the base material, and the electrode is formed on the top surface, thereby suppressing the busbar from becoming convex with respect to the electrode surface. This makes it possible to arrange the partitions vertically above the busbars, thereby avoiding voltage drop due to the transparent electrodes under the partitions. Therefore, as shown in Table 1, compared with the element of the comparative example, the uniformity of the coloring density of the element can be improved.

In addition, in the element of the example, since it is possible to arrange the partition wall vertically above the bus bar, the bezel can be obtained by cutting the glass base material at the position of the cutting line 113 indicated by the dashed line in FIG. 8(c). It is also possible to make the part small and to have a neat appearance.

In summary, it can be said that the following effects can be obtained from this embodiment.
・When coating the surface layer of a base material, uniform coating can be performed with a small difference in level.
・The degree of freedom in bus bar arrangement can be increased.
・It is possible to provide an element with high coloring uniformity.
・The bezel portion can be made smaller, and the quality of the appearance can be improved.

<<Example 3>>
(1) Fabrication of EC Element Body (1a) Fabrication of EC Element Body of Example Using the same method as in Example 1, an EC element body is fabricated with the following three changes.
A. Both the depth of the groove 107 for forming the busbar and the thickness t of the busbar 105 are set to 20 μm.
B. The distance between the electrodes is set to 25 μm by using a UV-curing sealing material mixed with 25 μm spacer beads as the partition wall 104 .
C. Assume that the effective optical area is 10 mm×10 mm.

(1b) Fabrication of EC Element Body of Comparative Example Using the same method as in Example 1, an EC element body is fabricated with the following changes. A. Assume that the effective optical area is 10 mm×10 mm.

(2) Injection of electrolyte solution An EC element is obtained by injecting an electrolyte solution and sealing in the same steps as in Example 1.

(3) Evaluation A driving voltage of 0.62 V was applied to the EC device for 10 seconds to color it, and then the decoloring response time when short-circuited was measured. The decolorization response time was calculated as the time required for ΔOD to become 1/100 of the coloring time. Table 2 shows the results.

In the element of the embodiment, by embedding the busbars in the substrate, it is possible to reduce the distance between the electrodes while maintaining a sufficient thickness of the busbars. As a result, in the element of the example, it is possible to realize an element with an inter-electrode distance (25 μm), which is impossible in the element of the comparative example because the busbars are in contact with each other. As a result, it can be seen that the decoloring response speed can be greatly improved as compared with the element of the comparative example.

In summary, it can be said that the following effects can be obtained from this embodiment.
・The degree of freedom in bus bar thickness can be increased.
・The degree of freedom of the inter-electrode distance can be increased.
・The response speed can be improved.

100: EC element, 101: electrode, 102: base material, 103: EC layer, 104: partition wall, 105: bus bar, 106: bezel part

Claims (10)

A pair of substrates, a pair of electrodes interposed between the pair of substrates, an electrochromic layer interposed between the pair of electrodes, and bus bars respectively connected to the pair of electrodes. and an electrochromic device having
Having a partition between the pair of electrodes,
Having a space surrounded by the pair of electrodes and the partition,
Having the bus bar outside the space,
The substrate and the electrode have a busbar spacing portion that increases the distance between the busbar connected to one of the pair of electrodes and the busbar connected to the other of the pair of electrodes,
The electrochromic device , wherein the busbar separation portion is a concave portion provided in the base material and an embedded portion in which the busbar provided in the electrode is embedded. 2. The electrochromic device according to claim 1, wherein the electrical resistance of said bus bar is smaller than the electrical resistance of said electrode. 3. The electrochromic device according to claim 1, wherein the distance between said pair of electrodes is 100 [mu]m or less. 4. The electrochromic device according to claim 1, wherein the bus bar is arranged such that the longitudinal direction of the bus bar is along the longitudinal direction of the electrode. An optical filter comprising the electrochromic element according to any one of claims 1 to 4 and an active element connected to the electrochromic element. An image pickup optical system having a plurality of lenses, an image pickup device for receiving light that has passed through the image pickup optical system, and the electrochromic device according to any one of claims 1 to 4 . Imaging device. An electrochromic device according to any one of claims 1 to 4 , an active device connected to the electrochromic device, and a reflecting member that reflects light passing through the electrochromic device. electrochromic mirror. 8. The electrochromic mirror according to claim 7 , wherein said reflecting member is one of said pair of substrates. 8. The electrochromic mirror of claim 7 , wherein the reflecting member is one of the pair of electrodes. A window comprising: the electrochromic element according to any one of claims 1 to 4 ; and an operating section for changing the transmittance of the electrochromic element.

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