Smart window including three-dimensional structure

Abstract

The present invention relates to a smart window and an electronic device including same and, more specifically, to a smart window and an electronic device including same, the smart window including: an upper electrode layer; a lower electrode layer; and an optical characteristic adjustment layer including a nano-charged particle solution between the upper electrode layer and the lower electrode layer, wherein the optical characteristic adjustment layer includes: a three-dimensional well array layer which contains the nano-charged particle solution and is a structure having an upper end and a lower end asymmetrical to each other; and a cover layer for covering the three-dimensional well array, and the nano-charged particle solution has a refractive index which is the same as or different from the refractive index of the three-dimensional well array.

Description

Smart windows containing three-dimensional structures

[0001] A smart window including a three-dimensional structure according to embodiments of the present invention is provided.

[0002] As energy issues become increasingly serious in modern society, demand for smart window technology to improve energy efficiency in buildings is increasing. Smart windows can be either electrically powered or non-electrically powered, switching their on / off state automatically based on external conditions. Of these, electrically powered ones offer the advantage of allowing users to switch the on / off state whenever they want, depending on their convenience.

[0003] Representative technologies for smart windows using electricity include electrochromism, polarized particle devices, and polymer-dispersed liquid crystals (PLCs). Electrochromism has limitations, including high manufacturing costs and slow response times, which can reach tens of minutes per square meter, depending on the area. PLCs are also expensive to manufacture and difficult to synthesize stably. Furthermore, PLCs present challenges with haze-free viewing angles due to variations in the refractive index of the droplets when in a transparent state.

[0004] According to one embodiment, the present invention provides a smart window including a three-dimensional structure in which optical properties (e.g., optical transmittance) are controlled by using dispersion or concentration of nano-charged particles within the three-dimensional structure, and energy efficiency is improved, in order to solve the above-mentioned problems.

[0005] According to one embodiment, the present invention provides a transparent display including a smart window according to embodiments of the present invention.

[0006] According to one embodiment, the present invention provides an electronic device including a smart window according to embodiments of the present invention.

[0007] However, the problems to be solved by the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0008] According to embodiments, a smart window includes a transparent substrate, an upper electrode layer; a lower electrode layer; an optical property control layer including an insulator and a nano-charged particle solution between the upper electrode layer and the lower electrode layer; wherein the optical property control layer includes a three-dimensional well array layer containing the nano-charged particle solution and having an asymmetrical structure at the top and bottom; and a cover layer covering the three-dimensional well array; wherein the refractive index of the nano-charged particle solution may be the same as the refractive index of the three-dimensional well array or may have a difference in the range of -5% to 5% of the refractive index of the three-dimensional well array.

[0009] According to one embodiment, the nano-charged particle solution includes one or more types of nano-charged particles selected from the group consisting of polymers such as carbon black, metal oxides such as TiO2, and colored organic / inorganic pigments, and the concentration of the nano-charged particle solution may be 0.1 mass% to 5 mass%, and the size of the nano-charged particles may be 50 nanometers to 10 micrometers (㎛).

[0010] In one embodiment, the three-dimensional well is a cone or a polyhedron, the height of the three-dimensional well is 10 micrometers (㎛) to 1 millimeter (mm), the bottom width is 10 micrometers (㎛) to 1 millimeter (mm), the aspect ratio is 0.5 to 2, and the charged particles within the three-dimensional well may be concentrated at the apex of the three-dimensional well when an electric signal is applied.

[0011] According to one embodiment, the optical property control solution is an Isopar series solution layer in which carbon black nanoparticles are dispersed, the three-dimensional well array layer includes a polyacrylic polymer, the optical property control layer has an optical transmittance of 40% or more when a charge is applied, the cover layer has a thickness of 100 nanometers (nm) to 1 micrometer (㎛), includes the same polymer as the optical property control layer, and the cover layer may have a flat surface disposed on the three-dimensional well array.

[0012] According to one embodiment, an insulating layer may be further included between the optical property control layer and the lower electrode and between the cover layer and the upper electrode.

[0013] According to one embodiment, the insulating layer may be of a material different from or the same as the optical property control layer.

[0014] According to embodiments of the present invention, an electronic device may include a smart window; according to embodiments of the present invention.

[0015] According to one embodiment, the smart window may have optical characteristics (e.g., optical transmittance) and response speed controlled by at least one of a driving voltage, a direct current voltage, and an alternating current voltage.

[0016] In one embodiment, the smart window can be applied to a transparent display.

[0017] In one embodiment, the transparent display may be a full color display.

[0018] According to one embodiment, the present invention can provide a smart window device that is opaque when in an ON state and transparent when in an OFF state by utilizing the properties of nano charged particles.

[0019] According to one embodiment, the present invention can provide a transparent smart window with high power efficiency and improved response speed by utilizing the properties of nano charged particles.

[0020] According to one embodiment, the smart window of the present invention can be utilized as a transparent display applicable to various electronic devices and mechanical devices.

[0021] According to one embodiment, the smart window of the present invention can be operated with low power, thus providing a good energy saving effect, and can be applied to large-area displays such as electronic billboard displays and vehicle displays.

[0022] FIG. 1 is an exemplary diagram illustrating the configuration of a smart window of the present invention according to one embodiment.

[0023] FIG. 2 is a schematic diagram of a driving mechanism of a smart window of the present invention according to one embodiment.

[0024] FIG. 3 shows experimental results comparing the change in transmittance of a smart window without a micro-pyramid structure and a smart window with a micro-pyramid structure, according to one embodiment, wherein: a) an ON / OFF photograph and b) a graph of response time according to the change in transmittance. Here, the voltage is a DC voltage.

[0025] FIG. 4 is an experimental result comparing the transmittance according to the concentration of nano-charged particles and the driving voltage in a smart window having a micro-pyramid structure of the present invention, according to one embodiment, including a) an ON / OFF photograph according to the concentration of nano-charged particles, b) a graph of transmittance according to the concentration of nano-charged particles, and c) a graph of transmittance according to the driving voltage. Here, the voltage is a direct current voltage.

[0026] FIG. 5 shows, according to one embodiment, a change in transmittance according to the application of an AC voltage to a smart window having a micro pyramid structure of the present invention and the results of repeated experiments thereof, including a) an ON / OFF photograph, b) a response time graph according to a change in transmittance, and c) a graph of a repeated experiment of a change in transmittance.

[0027] Figure 6 illustrates a process of manufacturing a smart window of the present invention according to one embodiment.

[0028] FIG. 7 compares the transparency of a device according to the difference in refractive index between a nano-charged particle solution of the present invention and a three-dimensional well array according to one embodiment, (a) when the refractive index difference is large and (b) when the refractive index difference is adjusted within an appropriate range.

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. In describing the present invention, detailed descriptions of related known functions or configurations will be omitted if it is determined that such detailed descriptions may unnecessarily obscure the gist of the present invention. In addition, the terms used in this specification are terms used to appropriately express preferred embodiments of the present invention, and may vary depending on the intention of the user or operator, or the customs of the field to which the present invention belongs. Therefore, the definitions of these terms should be determined based on the contents throughout this specification. The same reference numerals presented in each drawing represent the same elements.

[0030] Throughout the specification, when we say that an element is "on" another element, this includes not only cases where the element is in contact with the other element, but also cases where another element exists between the two elements.

[0031] Throughout the specification, when a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components.

[0032] Hereinafter, the smart window of the present invention will be described in detail with reference to embodiments and drawings. However, the present invention is not limited to these embodiments and drawings.

[0033] FIG. 1 is an exemplary diagram illustrating a configuration of a smart window according to embodiments of the present invention. In FIG. 1, the smart window may include a lower electrode (100), an optical property control layer (200) including nano-charged particles, and an upper electrode (300).

[0034] According to one embodiment, the lower electrode (100) and the upper electrode (300) are electrodes for applying an electric signal (e.g., charge or voltage) to the optical property control layer (200) and may be transparent electrodes. The lower electrode (100) and the upper electrode (300) may include a conductive metal oxide (e.g., TiO2, ITO, FTO, etc.), a conductive carbon-based material, a conductive polymer, etc. known in the technical field of the present invention.

[0035] According to one embodiment, the lower electrode (100) and the upper electrode (300) may each be coated with a conductive material (e.g., a conductive layer (120, 320)) for implementing the transparent electrode mentioned on a transparent substrate (110, 310). The transparent substrate may be a rigid substrate (e.g., a glass substrate) or a flexible substrate (e.g., flexible glass, polymer film). The flexible substrate can utilize its flexibility to apply a smart window to a curved or bent substrate.

[0036] According to one embodiment, the insulating layer (400a, 400b) or cover layer (P1) coated on the transparent substrate or conductive material layer of the lower electrode (100) and the upper electrode (300) may be in contact with the optical property control layer (200).

[0037] According to one embodiment, the optical property control layer (200) may include a three-dimensional well array layer (210) including a nano charged particle solution (NP); and a cover layer (P1) covering the three-dimensional well array layer (210).

[0038] According to one embodiment, the optical property control layer (200) induces a change in dispersion according to the movement of nano-charged particles by an electric signal (e.g., charge or voltage), and as a result, the optical property (e.g., light transmittance) can be controlled. In addition, when a dye or pigment is coated or mixed into the nano-charged particles or the optical property control layer (200) is dyed, the luminescence properties, color development properties, etc. can be controlled by the dispersion or concentration (e.g., bottom alignment or peak concentration) of the nano-charged particles. According to one embodiment, the optical property control layer (200) includes a nano-charged particle solution, and the nano-charged particle solution is a dispersion solution in which nano-charged particles are dispersed in a liquid (i.e., a solvent), and can be configured at a concentration that allows the movement of nano-charged particles by application of an electric signal (e.g., charge or voltage). For example, the nano-charged particles (based on the total weight of the nano-charged particle solution) are 0.1 wt% to 10 wt%; 0.1 wt% to 8 wt%; or 1 wt% to 5 wt%. By applying the mentioned content range, the response speed can be improved and the difference in light transmittance can be increased according to the on / off state by an electric signal (e.g., charge or voltage). The liquid can include a solvent of the Isopar series (isoparaffin solvent; EXXONMOBIL CHEMICAL), and isopar G (CAS No.68551-16-6), isopar E(CAS No.68551-15-5, Isopar L (CAS No. 68551-17-7), Isopar H (CAS No. 68551-16-6 and Isopar It may include one or more selected from the group consisting of M (CAS No. 68551-19-9).

[0039] In one embodiment, the refractive index of the nano-charged particle solution may be the same as or different from the refractive index of the three-dimensional well array (layer). For example, the difference between the refractive indices of the nano-charged particle solution and the three-dimensional well array (layer) may be in the range of -5% to 5%; -3% to 3%; -2% to 3%; or -1% to 1% of the refractive index of the three-dimensional well array (layer) (220).

[0040] According to one embodiment, FIG. 7 compares the transparency of a device according to the difference in refractive index between a nano-charged particle solution and a three-dimensional well array, (a) when the difference in refractive index between the three-dimensional well and the nano-charged particle solution is large, and (b) when the refractive indices of the three-dimensional well and the nano-charged particle solution are adjusted to match or fall within the mentioned range. In FIG. 7, when the refractive indices do not match (a), scattering occurs, resulting in a problem of reduced transparency, while when the refractive indices are the same (b), clear transparency can be secured.

[0041] According to one embodiment, the nano-charged particles have a size of 50 nanometers (nm) to 10 micrometers (㎛) and may include at least one selected from the group consisting of carbon-based polymers such as carbon black, metal oxides such as TiO2, colored organic pigments, and inorganic pigments.

[0042] According to one embodiment, the three-dimensional well may be a three-dimensional structure having an asymmetrical upper and lower portions, and may be shaped like a cone, a polygonal pyramid (e.g., a pyramidal structure), or an obelisk, which narrows in an upward direction (or downward direction). The body of the obelisk may include three or more faces (e.g., three faces, four faces, or five faces). Preferably, the three-dimensional well may be a pyramidal structure. In the three-dimensional well, charged particles may be concentrated to an upper region (i.e., an apex region) by an electric signal (e.g., a charge or voltage), thereby changing optical characteristics (e.g., optical transmittance). For example, when no electric field is applied within the three-dimensional well, the nano-charged particles are evenly distributed, so the area through which light passes is narrowed (e.g., opaque), and when an electric field is applied, the nano-charged particles are gathered or aligned at the apex of the three-dimensional well (e.g., pyramid structure) by the electric force, so the area through which light passes is widened, and transparency can be increased.

[0043] According to one embodiment, referring to FIG. 2, in the smart window of the present invention, the optical characteristic control layer (200) can change the ON / OFF state by moving nano-charged particles by an electric signal (e.g., charge or voltage) within an asymmetric structure such as a micro-pyramid. In the ON state, the nano-charged particles can be concentrated in the upper region (i.e., the apex region) of the micro-pyramid to increase the light transmittance. In the OFF state, the nano-charged particles can be dispersed within the structure to decrease the light transmittance.

[0044] In one embodiment, the three-dimensional wells may be arranged in a continuous manner (i.e., the arrangement spacing is about 0) or may be arranged at a spacing greater than 0; 10 micrometers (㎛) to 0.5 millimeters (mm); 10 micrometers (㎛) to 0.1 millimeters (mm); 10 micrometers (㎛) to 0.2 millimeters (mm). In one embodiment, the three-dimensional well may have a width (or diameter or width) (e.g., width at the bottom) of 10 micrometers (㎛) to 1 millimeter (mm). In one embodiment, the height of the three-dimensional well may be 10 micrometers to 1 millimeter (mm); 100 micrometers (㎛) to 1 millimeter (mm); or 10 micrometers (㎛) to 0.1 millimeter (mm). Alternatively, the height of the three-dimensional well may be 99% or less of the thickness of the optical property control layer (200); 90% or less; 85% or less; 80% or less; or 75% or less. For example, it may be 99% to 95%; or 99% to 97%. That is, the apex of the three-dimensional well is formed at a certain depth from the surface of the optical property control layer (200), so that a thin gap may be formed between the upper surface (or lower surface) of the optical property control layer (200) and the apex of the three-dimensional well. According to one embodiment, the aspect ratio (ratio of the height to the bottom (or top) width or diameter) of the three-dimensional well may be 1 to 5:1; 1 to 3:1; or 1 to 2:1. The bottom or top of the three-dimensional well may be the opposite surface of the apex.

[0045] According to one embodiment, each well in the three-dimensional well array (210) may contain the same or different nano-charged particle solutions. For example, the nano-charged particle solutions may differ in at least one or a combination of the type, shape, concentration, and particle size of the nano-charged particles.

[0046] In one embodiment, the transmittance (e.g., transmittance in the on state and off state) can be controlled by changing the three-dimensional well structure in the three-dimensional well array (210).

[0047] According to one embodiment, the optical characteristic control layer (200) can provide individually controlled optical characteristics (e.g., difference in transmittance) according to ON / OFF by controlling at least one of the concentration, type, driving voltage, and type of electric signal of nano charged particles within the three-dimensional well. This can individually control the optical characteristics for each three-dimensional well in a three-dimensional well array or individually control them according to a unit composed of a plurality of three-dimensional wells.

[0048] According to one embodiment, the optical property control layer (200) can secure transparency even when a three-dimensional well array exists by adjusting the refractive index between the three-dimensional well and the liquid in which the nano-charged particles are dispersed. The optical property control layer (200) can control changes in transmittance by being sufficiently dark when in the OFF state and sufficiently transparent when in the ON state by evenly dispersing the nano-charged particles within the three-dimensional well.

[0049] In one embodiment, the three-dimensional well array layer (210) in the optical property control layer (200) may be transparent and include a low refractive index polymer, for example, a polyurethane polymer or a polyacrylic polymer. In one embodiment, the optical property control layer (200) may have a thickness of 10 micrometers (㎛) to 1 millimeter (mm); 100 micrometers (㎛) to 1 millimeter (mm); or 10 micrometers (㎛) to 0.1 millimeter (mm). In one embodiment, the three-dimensional well array (layer) (210) may be transparent.

[0050] In one embodiment, the smart window can provide a light transmittance of 50% or more; 70% or more; 80% or more; or 90% or more when an electrical signal is applied (e.g., in an ON state).

[0051] According to one embodiment, the cover layer (P1) covers and seals the three-dimensional well array layer (210), which is intended to prevent leakage of the nano-charged particle solution. One surface disposed on and in contact with the three-dimensional well array (210) may be flat. The cover layer (P1) may be disposed on the open lower surfaces of the three-dimensional wells in the three-dimensional well array layer (210), thereby covering and sealing them.

[0052] According to one embodiment, the cover layer (P1) may be composed of the same components as the three-dimensional well array layer (210). The cover layer (P1) may be transparent or optionally opaque. For example, it may include a polyacrylic polymer or a polyurethane polymer. This can match the refractive index with the nano-charged particle solution, thereby increasing the light transmittance or the difference in light transmittance between ON and OFF depending on the electric signal. Furthermore, the three-dimensional well array can be stably sealed by the flexible polyurethane polymer. The cover layer (220) can prevent a short circuit phenomenon and prevent the leakage of the charged particle solution, thereby improving the durability of the smart window.

[0053] According to one embodiment, an insulating layer (400a, 400b) may be included between the cover layer (220) and the electrode layer (100 or 300). According to one embodiment, an insulating layer (400a, 400b) may be included between the photoactive layer (200) and the electrode layer (100 or 300). The insulating layer (400a, 400b) may be in contact with a conductive layer (120a or 120b) formed on a transparent substrate (110a or 110b) of the electrode layer (100 or 300). The insulating layer (400a, 400b) may be applied without limitation as long as it is an insulating material having light transmittance (e.g., transparency), and may include, for example, SiO2, a polymer, etc. The insulating layer (400a, 400b) may be the same material as the three-dimensional well array. The thickness of the insulating layer (400a, 400b) may be 20 nanometers to 1 micrometer; 50 nanometers to 1 micrometer; 100 nanometers to 1 micrometer; 200 nanometers to 800 nanometers; or 300 nanometers to 500 nanometers.

[0054] According to one embodiment, the smart window can have its transmittance and response speed controlled by at least one of a driving voltage, a direct current voltage, and an alternating current voltage. For example, the transmittance difference and response time can be adjusted by varying the concentration of nano-charged particles and the driving voltage, direct current voltage, and alternating current voltage.

[0055] According to one embodiment, FIGS. 3 to 5 illustrate the operation of the smart window of the present invention and evaluate its performance.

[0056] FIG. 3 illustrates experimental results comparing the change in transmittance of a smart window without a micro-pyramid structure and a smart window with a micro-pyramid structure, according to an embodiment. Here, the voltage is a direct current voltage. (a) A photograph of a smart window in an ON / OFF state, and (b) A graph of transmittance according to response time in an ON / OFF state. Here, a solution in which nano-charged particles are dispersed can be filled within a well of a micro-pyramid structure having a base of 20 μm and a height of 10 μm.

[0057] Figure 3 shows the results of an ON / OFF experiment of a smart window with a micro-pyramid structure and a smart window without a micro-pyramid structure. In the case of a smart window without a micro-pyramid structure, when voltage is applied, nano-charged particles move to the top layer by electric force, so the transmittance increases, but since they move irregularly to the top layer, the degree of increase in transmittance is minimal.

[0058] On the other hand, in the case of a smart window with a micro-pyramid structure, when voltage is applied, the nano-charged particles move to the apex of the pyramid due to the electric force, so the transmittance changes significantly. That is, when moving to the apex of the pyramid, the area where the nano-charged particles are gathered is very narrow, so the transmittance in the ON state is higher than that of a smart window without a pyramid structure. When the voltage is removed, the nano-charged particles are dispersed again within the device due to the electric repulsion between them, and the transmittance decreases.

[0059] FIG. 4 is an experimental result comparing the transmittance according to the concentration of nano-charged particles and the driving voltage in a smart window having a micro-pyramid structure of the present invention according to one embodiment, showing a) an ON / OFF photograph according to the concentration of nano-charged particles, b) a graph of transmittance according to the concentration of nano-charged particles, and c) a graph of transmittance according to the driving voltage. Here, the voltage is a direct current voltage.

[0060] In Fig. 4, it was confirmed that there was a difference in transmittance when the concentration and driving voltage of the nano charged particles were changed, and this can be used to select the most appropriate concentration and driving voltage of the nano charged particles. The difference in ON / OFF transmittance was most prominent when the nano charged particles were 1.5 wt%, and the most efficient difference in transmittance was confirmed when the driving voltage was 30 V.

[0061] FIG. 5 shows, according to one embodiment, a change in transmittance according to the application of an AC voltage to a smart window having a micro pyramid structure of the present invention and the results of repeated experiments thereof, including a) an ON / OFF photograph, b) a response time graph according to a change in transmittance, and c) a graph of a repeated experiment of a change in transmittance.

[0062] In the implementation of the smart window in Fig. 5, response time is also an important factor, so an AC voltage was applied to reduce the response time. When the AC voltage was applied, the polymer used to create the pattern continuously charged and discharged, so charging did not occur continuously. Therefore, when the AC voltage was applied, the nano-charged particles dispersed more quickly than when the DC voltage was applied when returning from the ON state to the OFF state. In addition, since the polymer did not charge, the smart window could be operated multiple times with similar transmittance, allowing for reversible use.

[0063] According to one embodiment, when no electric signal is applied, the black charged nano particles are evenly distributed within the micro pyramid structure, preventing light from passing through. When an electric signal is applied, the charged nano particles are gathered at the apex of the micro pyramid structure by electric force, increasing the area through which light can pass through, thereby increasing the transmittance. Therefore, the present invention can provide a function as a smart window that changes the ON / OFF state by an electric field.

[0064] According to one embodiment, the smart window may be applied to a transparent display. For example, the transparent display may combine a smart window and a TFT (Thin Film Transistor), and the three-dimensional wells of the optical characteristic control layer (200) of the smart window may be pixelated individually or as a unit of multiple three-dimensional wells.

[0065] According to one embodiment, the transparent display can provide a full-color transparent display capable of implementing RGB by controlling the nano-charged particle configuration (e.g., type, density (concentration), size, shape, etc.) of each pixel or introducing (e.g., coating) a material having color-emitting or luminescent properties to the nano-charged particles.

[0066] According to one embodiment, the smart window can be applied to a flexible transparent display by applying a flexible electrode substrate.

[0067] According to one embodiment, the present invention may provide an electronic device including a smart window. The electronic device may include a transparent display including the smart window of the present invention.

[0068] According to one embodiment, FIG. 6 illustrates a process of a method for manufacturing a smart window (e.g., the start window of FIGS. 1 and 2) according to embodiments of the present invention. In FIG. 6, the method for manufacturing the smart window may include: preparing an electrode layer; forming an optical property control layer on the electrode layer; forming a cover layer on the electrode layer; and bonding the cover layer and the optical property control layer. According to one embodiment, the method for manufacturing the smart window may form the optical property control layer on the electrode layer using a relatively simple method called soft lithography, and may enable a large-area process. That is, the method may form a three-dimensional well array layer of the optical property control layer on a transparent substrate of the electrode, fill the structure with a nano-charged particle dispersion solution, and allow the nano-charged particles to move therein by an electric signal. In addition, a process may be utilized for sealing the three-dimensional well array layer using an electrode and forming and bonding a cover layer on a substrate of an opposite electrode to prevent an electrical short.

[0069] According to one embodiment, the step of preparing an electrode layer is to prepare electrodes to be applied as lower and upper electrodes, which may be a transparent substrate coated with a layer of a conductive material. For example, the substrate may be an ITO-coated glass substrate.

[0070] According to one embodiment, the step of manufacturing the optical property control layer may include manufacturing a three-dimensional well array layer and a cover layer, respectively, using the prepared electrode as a substrate. That is, the step may include manufacturing a three-dimensional well array layer and a step of manufacturing a cover layer.

[0071] According to one embodiment, the step of manufacturing a three-dimensional well array layer includes the step of manufacturing a relief pyramid mold of PDMS (Polydimethylsiloxane); the step of spin-coating a curable polymer (e.g., PUA (Polyurethaneacrylate)) on the substrate of the prepared electrode;

[0072] The method may include a step of performing a soft lithography process using a positive pyramid PDMS mold on the polymer coating layer and curing the process to form a negative three-dimensional well array; and a step of injecting a nano-charged particle solution into the three-dimensional well.

[0073] According to one embodiment, the step of manufacturing a three-dimensional well array layer may include manufacturing a negative pyramid mold master (e.g., having a base of about 20 μm and a height of about 10 μm) by ultra-fine mold processing, and using this, a positive PDMS mold may be manufactured using PDMS having low surface energy. The curable polymer is PUA, which is a UV-curable polymer, and PUA may have a low refractive index and a refractive index that can be matched with that of a solvent (or solution) in which nano-charged particles are dispersed. The curing may be UV-cured (i.e., room temperature curing) by UV irradiation, and when the PDMS mold is removed, a negative three-dimensional well array layer may be formed on a substrate of an electrode (i.e., an ITO-coated glass substrate).

[0074] According to one embodiment, the electrode used in the step of manufacturing the three-dimensional well array layer may be an upper transparent electrode or a lower transparent electrode. The coating may be performed using a spray coating method in addition to spin coating.

[0075] According to one embodiment, the step of forming the cover layer may include forming the cover layer on the substrate of the prepared electrode, including the steps of: spin-coating a curable polymer on the substrate of the electrode (i.e., an ITO-coated glass substrate); performing a soft lithography process using a PDMS mold without any pattern (i.e., a flat PDMS mold) on the curable polymer coating layer, and curing the soft lithography process to form a flat patterned cover layer; and performing the lithography process and curing using the flat PDMS mold to perform UV curing while blocking contact with oxygen. The polymer is an insulating polymer that prevents a short-circuit phenomenon that occurs when current directly flows through the UV-curable polymer, and has the same composition as the optical property control layer, and can seal a three-dimensional well array layer.

[0076] According to one embodiment, the step of combining the cover layer and the optical property control layer may include combining an electrode (e.g., a lower electrode) on which the cover layer is formed and an electrode (e.g., an upper electrode) on which the optical property control layer is formed, which may be combined to cover and seal an open surface of the three-dimensional well array layer of the optical property control layer. The cover layer may be positioned on the open surface of the three-dimensional well array layer of the optical property control layer to perform sealing. Through such sealing, the structural stability of the device is ensured, evaporation of the solution of charged particles is prevented, and movement between the three-dimensional wells (e.g., pyramids) is eliminated, so that each of the three-dimensional wells (e.g., pyramids) can be filled with liquids containing particles having different properties.

[0077] Although the embodiments described above have been described with limited examples and drawings, those skilled in the art will recognize that various modifications and variations are possible based on the above teachings. For example, appropriate results can be achieved even if the described techniques are performed in a different order than described, and / or the described components are combined or combined in a different manner than described, or are replaced or substituted with other components or equivalents. Therefore, other implementations, other embodiments, and equivalents of the claims also fall within the scope of the claims described below.

Claims

1. Upper electrode layer; lower electrode layer; and An optical property control layer including a nano-charged particle solution between the upper electrode layer and the lower electrode layer; Including, The above optical property control layer comprises a three-dimensional well array layer containing a nano-charged particle solution and having an asymmetrical structure at the top and bottom; and a cover layer covering the three-dimensional well array. Including, The refractive index of the above nano charged particle solution is the same as the refractive index of the three-dimensional well array or has a difference in the range of -5% to 5% of the refractive index of the three-dimensional well array. Smart window.

2. In paragraph 1, The above nano charged particle solution Containing one or more types of nano charged particles selected from the group consisting of carbon black, metal oxide, organic pigment and inorganic pigment, A smart window, wherein the size of the nano charged particles is 50 nanometers to 10 micrometers.

3. In paragraph 1, A smart window, wherein the concentration of the above nano charged particle solution is 0.1 wt% to 10 wt%.

4. In paragraph 1, The above three-dimensional well is a cone or a polyhedron, The height of the above three-dimensional well is 10 micrometers to 1 millimeter (mm), the top width is 10 micrometers to 1 millimeter (mm), and the aspect ratio is 0.5 to 2. Smart window.

5. In paragraph 1, A smart window in which charged particles within the three-dimensional well are concentrated at the vertex of the three-dimensional well when an electric signal is applied.

6. In paragraph 1, The above optical property control layer comprises a polyacrylic polymer, A smart window, wherein the optical property control layer has an optical transmittance of 40% or more when a charge is applied.

7. In paragraph 1, The above cover layer has a thickness of 100 nanometers to 1 micrometer, Containing the same polymer as the above optical property control layer, A smart window, wherein the cover layer is a flat surface disposed on the three-dimensional well array.

8. In paragraph 1, An insulating layer disposed between the optical characteristic control layer and the lower electrode, and between the cover layer and the upper electrode. Smart Window, which includes more.

9. In paragraph 8, A smart window, wherein the insulating layer is made of a material different from or identical to the optical property control layer.

10. Smart window of paragraph 1; Including, The above smart window is, An electronic device, the optical characteristics and response speed of which are controlled by at least one of a driving voltage, a direct current voltage, and an alternating current voltage.

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