KR20180010485A

KR20180010485A - A Device having changeable transparency and a Smart Window

Info

Publication number: KR20180010485A
Application number: KR1020160092643A
Authority: KR
Inventors: 윤영식; 권태균; 박문수
Original assignee: 주식회사 엘지화학
Priority date: 2016-07-21
Filing date: 2016-07-21
Publication date: 2018-01-31

Abstract

The present application relates to a variable transmittance element. The transmittance variable element of the present application comprises: an electrode having a network of conductive lines whose line width is specified; And a charged particle containing electrophoretic layer provided on the electrode. The variable transmittance element of the present application can be used in a smart window because of its large transmittance variable width.

Description

[0001] The present invention relates to a variable transmissivity element and a smart window including the variable transmissivity element,

The present application relates to a transmissive variable element and a smart window including the same.

Smart windows that can actively control the function of light reflection, mining, or heat transmission due to external light sources are expected to greatly improve residential culture and office environment. Such a smart window is typically implemented by polymer dispersed liquid crystal (PDLC), suspended particle devices (SPD), and electrochromic devices (ECD).

On the other hand, as a next-generation display, an electronic paper excellent in portability and capable of providing real-time information can be realized by electrophoresis. The electrophoretic display has a principle that a particle is moved by applying an electric field to a fluid in which charged particles such as a chromatic color or an achromatic color are dispersed and a user can perceive a color change such as black and white due to the movement of the particle Lt; / RTI > To use this electrophoresis method, it is necessary to apply an electric field constantly. The application of a continuous electric field has a problem of causing particle aggregation and shortening the lifetime of the display. Accordingly, techniques such as forming a partition wall in an upper layer of the electrode to prevent coagulation between particles have been applied. However, this technique also has various drawbacks. For example, when a barrier rib is formed on a pattern electrode, an overlay defect may occur due to film stretching during a roll-to-roll process, and a multi-layer pattern electrode formed with the barrier rib may cause a moire Thereby deteriorating the visibility of the display.

One object of the present application is to provide a variable transmittance element comprising an electrode having a network of conductive lines having a certain range of line widths.

Another object of the present invention is to provide a variable transmittance element using an electrophoretic method, wherein the change in transmittance before and after voltage application is significantly increased.

It is another object of the present invention to provide a smart window using an electrophoretic variable transmittance element.

The above and other objects of the present application can be resolved by the present application which is described in detail below.

In one example of the present application, the transmissive element of the present application comprises two opposing substrates including electrodes; And an electrophoretic layer including a plurality of charged particles.

In one example, the electrodes of the first substrate may comprise a network of conductive lines having a line width of 10 [mu] m or less.

In another example, the electrode included in the first substrate may have a pitch in the range of 5 mu m to 300 mu m.

In another example, the electrophoretic layer comprises a capsule, and the plurality of charged particles may be contained in a capsule together with a dispersion solvent.

In another example, the electrophoretic layer may further include a partition wall partitioning the internal space of the electrophoretic layer in which the charged particles and the dispersion solvent are present.

In another example, the charged particle has a (-) or (+) charge and is selected from among carbon black, ferric oxides, chromium copper (CrCu), or aniline black .

In another example, the capsule can be a spherical or elliptic spherical capsule having a diameter in the range of 1 [mu] m to 300 [mu] m.

In another example, the first substrate may be located in an incident path of an external light source.

In another example, the conductive line may comprise at least one of Ag, Cu, Al, Mg, Au, Pt, W, Mo, Titanium (Ti), nickel (Ni), or an alloy thereof.

In another example, the network shape of the conductive lines of the electrodes included in the first substrate may be amorphous.

In another example, the electrode included in the first substrate may be a metal mesh electrode having a network of conductive lines in a lattice form.

In another example, the first substrate may further include graphene or carbon nanotubes.

In a further example of the electrode of the second substrate, ITO (Indium Tin Oxide), In 2 O 3 (indium oxide :), indium galium oxide (IGO), FTO (Fluor doped Tin Oxide), AZO (Aluminium doped Zinc oxide, GZO, ATO, IZO, Niobium-doped titanium oxide, ZnO, CTO, or the like. And an OMO (oxide / metal / oxide) electrode.

In another example, the transmittance variable element includes a power source electrically connected to the electrode, and the power source may apply a voltage of a polarity opposite to the polarity of the charged particles to the first substrate electrode.

In another example, the electrode of the second substrate may have a network of the same conductive line as the first substrate, and the power source may apply a voltage of a polarity opposite to the polarity of the charged particles to the first substrate electrode or the second substrate It can be applied to the electrode.

In another example, the first and second substrates may include a light-transmitting substrate on the outer surface of the electrode.

In another example, the light transmittance of the element before voltage application is in the range of 0.1% to 10%, and the light transmittance of the element after voltage application may be in the range of 20% to 90%.

In another example of the present application, the present application may be a smart window including the transmissive variable element.

The present application can provide a variable transmittance element that can prevent or minimize a moire phenomenon without overlay defect during device manufacturing. The transmittance variable element of the present application can be used for a smart window because the transmittance variation width before and after the voltage application is significantly larger than that using the electrophoretic method.

Fig. 1 schematically shows a variable transmittance element according to an example of the present application and its operation principle. Specifically, FIG. 1A shows a device before voltage application, and FIG. 1B shows a device after voltage application. The device of the present application includes a lower plate electrode 20, a charged particle-containing capsule 30 in the electrophoresis layer, and an upper plate electrode 40 between the light-transmitting substrates 10 and 50. When the voltage is applied, Can change.
Figure 2 is a photograph of the shape of a conductive network that an electrode of a first substrate may have, according to one example of the present application. 2 (a) and 2 (c) show the concept of an amorphous electrode shape and pitch, and FIGS. 2 (b) and 2 (d) show electrodes and pitches of a metal mesh shape, respectively.
3 is an image of microcapsules usable according to one example of the present application.
4 is an image of a usable partition wall according to one example of the present application.
Fig. 5 is an image of an element manufactured according to Embodiment 1 of the present application, in which the difference in light transmittance seen before and after voltage application is photographed.

Hereinafter, a variable transmissivity element according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. For convenience of explanation, the size and shape of each constituent member shown may be exaggerated or reduced.

In one example of this application, the present application relates to a variable transmittance element. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 schematically shows a cross-section of a transmissive variable element that can be driven by an electrophoretic scheme according to one embodiment of the present application. 1 (a) schematically shows a cross-section of a device before voltage application to an electrode, and Fig. 1 (b) schematically shows a cross-section of a device after voltage application. As shown in the figure, the permeation of the external light 60 is limited by the black charged particles dispersed in the capsule before the application of the voltage, so that the transmittance of the device is very low. However, The transmittance of the external light 60 to the device can be significantly increased.

In order to realize a variable transmittance element, it is necessary that the change in light transmittance before and after voltage application is about 20% or more. More specifically, it is required to be at least about 40%, at least about 60%, or at least about 80%. Further, in order to secure the excellent visibility of the variable transmittance element, the moire phenomenon must be little or at least limited. Securing of the transmittance of the above-mentioned range or prevention of the moire phenomenon can not be achieved simply by using the transparent electrode conventionally used. In this connection, the element of the present application comprises an electrode consisting of a network of conductive lines having a line width of a certain numerical range; And an electrophoretic layer provided on the electrode. Accordingly, the transmittance variable element of the present application can not only have a change in the transmittance in the above-mentioned range but also prevent moire phenomenon and ensure excellent visibility. Unless otherwise specifically defined, the term " light " in the present application may refer to light having a wavelength in the visible range, for example, in the range of 380 nm to 780 nm. It should be noted that the term " phase " used in connection with the interposition positions in the present application is used in the meaning corresponding to " above " or " upper " Or may mean that there are other configurations between them.

The transmittance variable element of the present application may include two substrates and an electrophoretic layer. The two substrates may be referred to as a first substrate and a second substrate, respectively. In one example, an electrophoretic layer may be provided on the first substrate, and the second substrate may be provided on the electrophoretic layer. Each of the first substrate and the second substrate may include an electrode on a surface facing the electrophoretic layer. As described above, the device may include a first substrate, an electrophoretic layer, The electrodes included in the first substrate may be referred to as lower plate electrodes and the electrodes included in the second substrate may be referred to as upper plate electrodes. The order of bonding between substrates and the concept of a top plate or a bottom plate are relatively.

In one example, the electrodes included in the first substrate may have a conductive network formed by conductive lines. At this time, the line width of the conductive line may be 10 탆 or less. The lower limit of the line width is not particularly limited and may be, for example, 0.01 mu m or more, 0.1 mu m or more, 0.5 mu m or more, 1 mu m or more, or 3 mu m or more. A low resistance element can be realized through the line width in the above range. On the other hand, when the line width is larger than the above range, the pattern itself can be visually recognized, and since the charged particles after the voltage application are transferred to the wiring are also observed, the value of the product itself may be greatly deteriorated.

In another example, the electrode included in the first substrate may have a pitch of several hundreds of micrometers or less. For example, the lower limit of the pitch of the electrode may be 3 탆 or more, 5 탆 or more, 30 탆 or 50 탆 or more, and the upper limit of the pitch may be 350 탆 or less, 300 탆 or less, 200 탆 or less, Or 100 m or less. When the pitch is in the above range, overlay failure in the manufacturing process can be prevented. The term " pitch " in the present application may be defined differently depending on the network configuration of the electrode. For example, in the case of a metal mesh electrode, it may mean the length of one side of each cell having a uniformly formed rectangular shape in one direction. In the case of the amorphous electrode, since the size of each cell forming the electrode is not uniform, it may mean an average pitch calculated through the number of cells existing within a certain area of the electrode as described below.

(The number of cells existing within a certain area) x (average pitch) ² = the area of the electrode where the number of cells is present or the area of a part of the electrode

Figs. 2 (c) and 2 (d) show pitches of amorphous electrodes and metal mesh electrodes according to an example of the present application.

Electrodes having line widths and pitches in the above range may have a low resistivity, for example, a resistivity of 10 ^-5 ohm · m or less or 10 ^-7 ohm · m or less. At this time, the electrode may have a thickness in the range of 10 nm to 10 mu m or in the range of 100 nm to 5 mu m. The " thickness of the electrode " in the present application may mean the height of the electrode formed on the substrate.

Since the conventionally used high-resistance transparent electrode increases the intensity of the electric field applied to the electrode, a sufficient electrophoresis effect can not be obtained in the actual driving voltage range, and as a result, the light transmittance varies within the range of 0.1% to 90% It is difficult to realize a variable transmittance element. However, in the case of the present application including the electrode satisfying the resistance value in the above range, the intensity of the electric field applied to the electrode is reduced, and accordingly the voltage range in practical usable voltage range, for example, 10 V to 100 V A sufficient electrophoresis effect and a change in transmittance can be obtained.

The electrode included in the first substrate may include a metal component. Specifically, the conductive line of the first substrate electrode may be formed by a metal component. The kind of the usable metal component is not particularly limited. As a non-limiting example, a metal such as Ag, Cu, Al, Mg, Au, Pt, W, Mo, , Nickel (Ni), or an alloy containing them may be included in the electrode of the first substrate.

In one example, the electrode included in the first substrate may be an amorphous electrode in which the conductive line forms an irregularly shaped conductive network, as shown in FIG. 2 (a). The amorphous electrode not only prevents the moiré phenomenon but also significantly improves the overlay defect in the process because it can exist as a single or multiple conductive lines in any capsule or any part of the partition including charged particles . The conductive line forming the electrode when the first substrate electrode is amorphous may have an average line width in the range of 0.5 to 5 mu m and an average pitch in the range of 5 to 300 mu m although not particularly limited.

The amorphous electrode may be formed by mixing at least one of nanoparticles of the electrode forming metal components with two or more kinds of solvents to form a solution in a W / O emulsion state (water in oil) Drying, or drying and then a photointering step. The drying temperature is not particularly limited and may be, for example, 90 DEG C or higher.

In another example, the electrode included in the first substrate may be a metal mesh having a network in which a plurality of conductive lines are orthogonal to each other, as shown in FIG. 2 (b). Although not particularly limited, the metal mesh may be configured to have a line width of 0.5 m to 5 m and a pitch of 5 m to 300 m or less. The electrode of the first substrate having the line width and pitch in the above range can prevent overlay failure.

The method of preparing the metal mesh is not particularly limited, and various printing methods or patterning methods may be used. In one example, a metal mesh electrode may be provided through reverse offset printing, one of the roll-to-roll methods.

In one example, the electrode included in the first substrate may further include graphene or carbon nanotubes. For example, an electrode film having the above network is immersed in a solution in which graphene and / or carbon nanotubes are dispersed, or a solution in which graphene and / or carbon nanotubes are dispersed is sprayed onto an electrode film By way of example, graphene and / or carbon nanotubes can be coated or adsorbed onto the electrode. Electrodes further comprising graphene or carbon nanotubes can be further improved in conductivity. The content of graphene and carbon nanotubes is not particularly limited, but may be used within a range that does not lower the transparency of the electrode.

In another example, the electrode included in the first substrate may have a laminated structure. More specifically, the electrode may have a structure in which the plurality of amorphous electrodes mentioned above are laminated to each other or a plurality of metal mesh electrodes are laminated to each other, or the amorphous electrode and the metal mesh electrode are laminated to each other .

The electrophoretic layer may include a plurality of charged particles whose arrangement varies according to the polarity of a voltage to be applied. To this end, the charged particles may optionally be negative (-) or positive (+) charges. The charged particles are particles having a size of about several tens nm to several hundreds of nanometers, and a material capable of blocking light can be used. More specifically, the particles can have a size of less than 100 nm and include, for example, materials such as carbon black, ferric oxides, chromium copper (CrCu), or aniline black But is not limited thereto.

The charged particles can be included in the electrophoresis layer together with the solvent in which the charged particles are dispersed. The content ratio of the charged particles and the solvent in which the charged particles are dispersed is not particularly limited and may be suitably selected by those skilled in the art.

As the solvent in which the charged particles are dispersed, a known solvent such as a hydrocarbon-based solvent may be used without limitation. For example, isoparaffin-based solvents such as pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, isomers or mixtures thereof as well as common alkane solvents as well as alkane mixed substances of 6 to 13 carbon atoms Can be used. Specifically, isopar C, isopar G, isopar E (Exxon), ISOL-C (SK Chem), or ISOL-G (Exxon) may be used.

In one example, the electrophoretic layer may comprise a capsule. Specifically, the electrophoresis layer may include one or more capsules containing charged particles and a solvent therein. The method for preparing the capsules is not particularly limited and may be prepared through an oil in water (O / W) emulsion solution prepared through emulsification, for example. 3 is an image of a capsule obtained from an O / W (oil in water) emulsion solution.

The material for forming the capsule is not particularly limited. For example, water-soluble proteins, carbohydrates, vinyl-based polymers, (meth) acrylate-based polymers, urethane-based polymers, polycarbonate-based polymers and siloxane-based polymers may be used. More specifically, it is possible to use an alginate, gelatin, acacia gum, carboxymethyl cellulose, carrageenin, casein, albumin and cellulose phthalate, polymethlymethacrylate, polystyren, polyacrylamide, Various polymers such as polyurethane, polyurea, polypeptide, polycarbonate, polydimethylsiloxane, or polyolefin may be used as non-limiting examples.

The capsule may have a closed structure such as a spherical shape or an elliptic spherical shape. In one example, when the capsule is spherical, the capsule may have a diameter ranging from 1 [mu] m to 300 [mu] m. The upper limit of the capsule diameter may be 300 占 퐉 or less, 200 占 퐉 or less, or 100 占 퐉 or less, and the lower limit may be 1 占 퐉 or more, 5 占 퐉 or more, or 20 占 퐉 or more.

In one example, the electrophoresis layer comprising the capsule may be provided in the form of a film. For example, the film may be a film provided with a plurality of capsules inside the film of the film, the film including a solvent and charged particles. When the electrophoretic layer is provided in the form of a film, the electrophoretic layer may be bonded to the first substrate and the second substrate through a separate adhesive layer or the like by a known lamination method.

In another example, the electrophoresis layer comprising the capsule may be formed from a cured product of a coating composition comprising a capsule and a curable resin. The specific kind of the curable resin is not particularly limited and it suffices to include a curable functional group capable of curing through heat or photo-curing to fix the charged particle-containing capsule between the first and second substrates. Examples of the curable functional group include, but are not limited to, an acrylate group, an epoxy group, or an isocyanate group. The manner of applying the coating composition on the substrate is also not particularly limited.

In another example, the electrophoretic layer may comprise barrier ribs. More specifically, the electrophoresis layer may include one or more partition walls inside the electrophoresis layer that partition the space of the electrophoresis layer in which the charged particles and the solvent are present. The electrophoresis layer including the barrier ribs may be provided through a printing process such as roll-to-roll, photolithography, photoresist, or mold printing. For example, the barrier ribs may be provided by providing an acrylic or epoxy polymer layer on one of the substrates and patterning the polymer layer.

The manner in which the partition wall separates the space of the electrophoretic layer is not particularly limited. For example, when the first substrate has a rectangular cross section, a plurality of partition walls parallel to either one side of the first substrate and spaced from each other may be formed in a stripe shape, or a plurality of partition walls may cross each other, . The height or thickness of the barrier rib is not particularly limited and can be suitably controlled by those skilled in the art. Fig. 4 is an image of a lattice-shaped bulkhead usable according to an example of the present application.

In one example, when the electrophoretic layer includes a partition wall, the charged particles and the solvent contained in the electrophoretic layer may be contained in a form directly filled without a capsule in a space defined by the partition wall. But are not limited to, die coating, casting, bar coating, slit coating, dispense, squeezing, screen printing, Or inkjet printing, the solvent and the charged particles can be filled into the respective partition walls of the electrophoresis layer.

In another example, when the electrophoretic layer includes a partition wall, the partition wall may include a capsule, and charged particles and a solvent may be contained inside the capsule. In this case, the capsule may be filled in the partition with the binder, and then fixed in the partition through curing.

In one example, the electrode included in the second substrate may include a metal oxide. A metal oxide is ITO (Indium Tin Oxide), In 2 O 3 (indium oxide :), IGO (indium galium oxide), FTO (Fluor doped Tin Oxide), AZO (Aluminium doped Zinc Oxide), GZO (Galium doped Zinc Oxide ), ATO (Antimony-doped Tin Oxide), IZO (Indium-doped Zinc Oxide), NTO (Niobium-doped Titanium Oxide), ZnO (Zinc Oxide), or CTO (Cesium Tungsten Oxide) no. In addition, the electrode of the second substrate may be an oxide / metal / oxide (OMO) electrode in which a metal layer such as silver, copper, or aluminum is interposed between the layers composed of the above-mentioned metal oxide. When the electrode of the second substrate includes the above-mentioned metal oxide, the first substrate may be located in an incident path where an external light source is irradiated to the device, as shown in Fig. Further, when the electrode material of the second substrate listed above is used, the power source can apply the voltage of the polarity opposite to the polarity of the charged particles to the first substrate electrode.

In another example, the electrodes included in the second substrate may be configured to have the same configuration or characteristics as the electrodes included in the first substrate. Specifically, the electrodes included in the second substrate may be configured to have a network of conductive lines having line widths in the above-mentioned ranges, or the material forming the conductive lines, the resistivity of the electrodes, And may be configured to be the same as the electrode of the substrate. In this case, the power source can apply the voltage of the polarity opposite to the polarity of the charged particles to the electrode of the first substrate or the electrode of the second substrate.

The transmissivity-variable element may further include a light-transmissive substrate having a transmittance of about 50% to 90% with respect to visible light on an electrode outer surface of the first substrate and an electrode of the second substrate. The type of the light-transmitting base material is not particularly limited, and transparent glass or polymer resin can be used, for example. More specifically, a polyester film such as PC (Polycarbonate), PEN (poly (ethylene naphthalate)) or PET (poly terephthalate), an acrylic film such as poly (methyl methacrylate) Or a polyolefin film such as PP (polypropylene) may be used, but the present invention is not limited thereto.

In one example, the first and second substrates may have a thickness in the range of 80 mu m to 1,000 mu m including both the electrode and the light-transmitting substrate.

The transmittance variable element may further include a power source electrically connected to the electrode. As described above, in the present application using the electrophoretic method, by applying a voltage of a polarity opposite to the charged particles contained in the electrophoretic layer to the electrodes of the first substrate or the second substrate through the power source, Can be increased. The power source may be electrically connected to the first substrate electrode and the second substrate electrode, respectively, and a voltage in the range of 5 V to 150 V, or in the range of 10 V to 100 V, or in the range of 10 V to 50 V, Thereby enabling the device to be implemented.

In one example, the light transmittance of the variable transmittance element may be in the range of 0.1% to 10%, but may be in the range of 20% to 90% after voltage application.

In another example of the present application, the present application is directed to a smart window. The smart window of the present application may be configured to include the transmissivity-variable element.

Hereinafter, the present application will be described in detail by way of examples. However, the scope of protection of the present application is not limited by the following embodiments.

Example One

Manufacture of electrode film on top plate

Through sputtering, a 100 탆 thick PET / ITO film on which ITO was deposited on a PET substrate was prepared to a size of 10 cm x 10 cm.

Bottom plate Manufacture of electrode film

Coated with a W / O emulsion solution containing Ag nanoparticles on a substrate and then dried at a temperature of about 100 DEG C to form an electrode having an amorphous network having a line width in the range of 5 mu m to 7 mu m and an average pitch of 65 mu m .

Of the electrophoretic layer Produce

(Isopar G, EXXONMOBIL CHEMICAL), and a gelatin-based 30 mu m-sized capsule in which carbon black having a size of 100 nm or less was dispersed in the solvent was prepared. At this time, the carbon black was treated to have a negative charge.

The capsules prepared above were applied to the first substrate electrode together with a coating solution containing an acrylic resin, and then UV-cured.

Fabrication of Transmittance Variable Element and Measurement of Transmittance Change

The lower electrode film and the upper electrode film thus prepared were laminated. A negative voltage was applied to the top plate electrode and a positive voltage was applied to the bottom plate electrode, and a voltage of about 30 V was applied.

Using a UV-vis spectrometer (Solidspec 3700), the change in transmittance to visible light before and after voltage application was measured. As a result of the measurement, the transmittance at the voltage unapplied state (0 V) was about 0.5%, but the transmittance was changed to about 75% after the voltage was applied (30 V). 5 is an image of a change in transmittance of the device of Example 1 before and after voltage application.

Example 2

Unlike Example 1, a metal mesh containing Al and having a line width of 5 占 퐉 and a pitch of 150 占 퐉 was used as a lower plate electrode. Otherwise, the variable transmittance device was manufactured in the same manner as in Example 1.

The change in transmittance before and after voltage application was measured in the same manner as in Example 1. As a result, it was confirmed that the transmittance at the voltage unapplied state (0 V) was about 3%, but the transmittance was changed to about 65% after the voltage application (30 V).

10: Transparent substrate
20: Lower plate electrode
30: charged particle containing capsule
40: top plate electrode
50: Transparent substrate
60: external light

Claims

A first substrate and a second substrate, the first substrate and the second substrate opposing each other; And an electrophoretic layer including a plurality of charged particles,
Wherein the electrode of the first substrate comprises a network of conductive lines having a line width of 10 microns or less.

The device according to claim 1, wherein the electrode of the first substrate has a pitch in the range of 5 mu m to 300 mu m.

The device according to claim 2, wherein the electrophoretic layer comprises a capsule, and the plurality of charged particles are contained in a capsule together with a dispersion solvent.

The electrophoretic display device according to claim 2, wherein the electrophoretic layer comprises: a solvent in which the charged particles are dispersed; And a partition wall partitioning the space in which the charged particles and the solvent are present.

5. The device of claim 4, wherein the plurality of charged particles are contained in the capsule together with the solvent.

The method according to any one of claims 1 to 5, wherein the plurality of charged particles are charged with negative (-) or positive (+) charges, and are selected from the group consisting of carbon black, ferric oxides, chromium copper (CrCu) Or aniline black.

The device according to any one of claims 3 to 5, wherein the capsule has a diameter in the range of 1 탆 to 300 탆.

The element according to claim 2, wherein the first substrate is located in an incident path of an external light source.

The conductive line according to claim 8, wherein the conductive line is made of a material selected from the group consisting of Ag, Cu, Al, Mg, Au, Pt, W, Titanium (Ti), nickel (Ni), or an alloy thereof.

10. The device of claim 9, wherein the network shape of the conductive lines of the electrodes of the first substrate is amorphous.

10. The device of claim 9, wherein the electrode of the first substrate is a metal mesh having a grid of conductive lines.

12. The variable transmittance element according to any one of claims 10 to 11, wherein the first substrate further comprises graphene or carbon nanotubes.

Claim 10 or 11. A method according to any one of claims, wherein the electrode of the second substrate, ITO (Indium Tin Oxide), In 2 O 3 (indium oxide :), indium galium oxide (IGO), FTO (Fluor doped Tin Oxide), AZO (Aluminum Doped Zinc Oxide), GZO (Galium Doped Zinc Oxide), ATO (Antimony Doped Tin Oxide), IZO (Indium Doped Zinc Oxide), NTO (Niobium Doped Titanium Oxide) CTO (Cesium Tungsten Oxide), or OMO (Oxide / Metal / Oxide) electrode.

The device of claim 13, wherein the variable transmittance element comprises a power source electrically connected to the electrode, and the power source applies a voltage of a polarity opposite to the polarity of the charged particles to the electrode of the first substrate.

12. The device of claim 10 or 11, wherein the electrode of the second substrate is an electrode having a network of the same conductive lines as the electrodes of the first substrate.

16. The method of claim 15, wherein the variable transmittance element comprises a power source electrically connected to the electrode, wherein the power source applies a voltage of a polarity opposite to the polarity of the charged particles to the electrode of the first substrate or the electrode of the second substrate Transmittance variable element.

3. The variable transmittance element according to claim 2, wherein the first and second substrates further include a light-transmitting substrate on an outer surface of the electrode.

3. The variable transmittance element according to claim 2, wherein the light transmittance of the element before voltage application is in the range of 0.1% to 10%, and the light transmittance of the element after voltage application is in the range of 20% to 90%.

A smart window comprising the variable transmissivity element according to claim 1.