Electromagnetic wave transmission film and window structure

Abstract

An electromagnetic wave transmission film according to embodiments of the present invention comprises: a substrate; a conductive pattern disposed on the substrate and including an electrode region and a hollow region; and a dummy pattern disposed in the hollow region on the substrate, and spaced apart from the electrode region. An aperture ratio of the dummy pattern may be 50% or less. The window structure according to embodiments of the present invention includes the electromagnetic wave transmission film according to the embodiments described above.

Description

Electromagnetic wave transparent film and window structure

[0001] The present invention relates to an electromagnetic wave transparent film and a window structure. More particularly, it relates to an electromagnetic wave transparent film and a window structure comprising a plurality of patterns.

[0002]

[0003] With the recent development of the information society, wireless communication technologies such as Wi-Fi and Bluetooth are being applied or built into display devices, electronic devices, buildings, the Internet of Things (IoT), and autonomous vehicles. Furthermore, with the recent advancement of mobile communication technology, antennas for high-frequency or ultra-high-frequency communication are being widely applied to windows, home appliances, vehicle windows, and building exteriors. For example, along with Wi-Fi, which operates in bands such as 2.4 GHz and 5 GHz, and Bluetooth, which operates in the 2.45 GHz band, 5G (5th-generation) communication systems, which operate in high-frequency bands (e.g., 28 GHz or higher), are being commercialized.

[0004] However, transmission loss may occur due to the atmosphere or obstacles (e.g., walls or car windows) present in the transmission path before the electromagnetic wave radiated from the transmitter reaches the receiver.

[0005] Electromagnetic waves in high-frequency or ultra-high-frequency bands have high transmission speeds and short wavelengths, making them difficult to diffract and resulting in relatively short transmission distances. For example, electromagnetic waves transmitted from a base station antenna may be lost, attenuated, or dissipated as they pass through walls or windows before reaching the receiver. This can result in reduced signal efficiency and coverage, and increased energy consumption to compensate for signal loss.

[0006] Additional design components may be required to suppress loss of electromagnetic waves radiated from antennas or radars and ensure reliability. For example, Korean Patent Publication No. 10-2011-0037262 discloses a surface wave suppression device.

[0007]

[0008] One object of the present invention is to provide an electromagnetic wave transparent film having improved radio wave transmittance in a specific frequency band.

[0009] One object of the present invention is to provide a window structure having improved radio wave transmittance in a specific frequency band.

[0010]

[0011] 1. An electromagnetic wave transparent film comprising: a substrate; a conductive pattern disposed on the substrate, the conductive pattern including an electrode region and a hollow region; and a dummy pattern disposed on the substrate within the hollow region and spaced apart from the electrode region, the dummy pattern having an opening ratio of 50% or less.

[0012] 2. In the above 1, the dummy pattern is an electromagnetic wave transparent film including a plurality of periodically arranged sub-patterns.

[0013] 3. In the above 2, the electromagnetic wave transparent film has an island pattern shape that is physically separated from each other.

[0014] 4. In the above 2, each of the sub-patterns has a circular or polygonal shape, an electromagnetic wave transparent film.

[0015] 5. An electromagnetic wave transparent film in the above 2, wherein the ratio of the width of the sub-pattern to the width of the conductive pattern is 0.1 or less.

[0016] 6. In the above 2, the width of the sub-patterns is greater than the spacing between adjacent sub-patterns, an electromagnetic wave transparent film.

[0017] 7. An electromagnetic wave transparent film in the above 1, wherein the aperture ratio of the dummy pattern is 10% or more.

[0018] 8. In the above 1, the conductive pattern has a ring shape or a loop shape, an electromagnetic wave transparent film.

[0019] 9. An electromagnetic wave transparent film, wherein in the above 1, the conductive pattern includes a first pattern and a second pattern that are physically spaced apart from each other, and the hollow region is defined as a region between the first pattern and the second pattern.

[0020] 10. In the above 9, the first pattern surrounds the border of the second pattern with the second pattern as the center in the plane direction, an electromagnetic wave transparent film.

[0021] 11. In the above 10, the first pattern has a circular or polygonal ring shape in the plane direction, an electromagnetic wave transparent film.

[0022] 12. In the above 10, the second pattern has a circular or polygonal island pattern shape, an electromagnetic wave transparent film.

[0023] 13. An electromagnetic wave transparent film in the above 1, wherein the area of ​​the electrode region is larger than the area of ​​the dummy pattern when observed in a planar direction.

[0024] 14. An electromagnetic wave transparent film in the above 1, wherein the electrode region of the conductive pattern and the dummy pattern have a solid structure.

[0025] 15. An electromagnetic wave transparent film in which one unit cell is defined by the conductive pattern and the dummy pattern in the above 1, and a plurality of the unit cells are arranged adjacent to each other and repeatedly on the substrate.

[0026] 16. In the above 1, the conductive pattern and the dummy pattern are an electromagnetic wave transparent film including a transparent conductive oxide.

[0027] 17. A window structure including an electromagnetic wave transparent film according to 1 above.

[0028] 18. A window structure according to 17 above, further comprising a lower substrate disposed under the substrate, and an air layer formed between the substrate and the lower substrate.

[0029]

[0030] Conductive patterns according to embodiments of the present invention may include electrode regions and hollow regions. The conductive patterns can selectively transmit, amplify, or reflect electromagnetic waves within a specific band. Accordingly, reflection, attenuation, and phase shift of electromagnetic waves within a desired band can be suppressed, and electromagnetic wave transmittance can be increased.

[0031] A dummy pattern having a predetermined aperture ratio can be formed within the hollow region of the conductive pattern. Heat flow and transfer through the hollow region can be blocked, and the thermal resistance and thermal insulation of the electromagnetic wave transparent film can be improved. The dummy pattern includes a plurality of periodically arranged sub-patterns, and both optical properties and electromagnetic wave transparent properties can be improved.

[0032]

[0033] FIG. 1 is a schematic plan view showing an electromagnetic wave transparent film according to exemplary embodiments.

[0034] Figure 2 is a schematic plan view that enlarges area A of Figure 1.

[0035] FIG. 3 is a schematic plan view showing a conductive pattern according to exemplary embodiments.

[0036] FIG. 4 is a schematic plan view showing an electromagnetic wave transparent film according to exemplary embodiments.

[0037] FIG. 5 is a schematic cross-sectional view showing an electromagnetic wave transparent film according to exemplary embodiments.

[0038] Figures 6 and 7 are schematic cross-sectional views showing window structures according to exemplary embodiments, respectively.

[0039] FIG. 8 is a graph showing the electromagnetic wave transmission loss of window structures according to Examples, Comparative Example 1, Comparative Example 2, and Comparative Example 4.

[0040]

[0041] Embodiments of the present invention provide a conductive pattern and an electromagnetic wave transparent film including the conductive pattern.

[0042] Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. However, the following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the contents of the invention described above, serve to further understand the technical concept of the present invention. Therefore, the present invention should not be interpreted as being limited to the matters described in such drawings.

[0043] The terms “upper”, “lower”, “first”, “second”, etc. used in the present invention indicate the relative positions of each component and do not imply an absolute superior-subordinate relationship.

[0044] FIG. 1 is a schematic plan view showing an electromagnetic wave transparent film according to exemplary embodiments.

[0045] Referring to FIG. 1, the electromagnetic wave transparent film may include a conductive pattern (10) and a dummy pattern (20).

[0046] The conductive pattern (10) may include an electrode region (12) and a hollow region (11). The hollow region (11) may refer to a hollow region such as a slot, slit, hole, or cavity formed within the conductive pattern (10) when observed in a planar direction.

[0047] The conductive pattern (10) can transmit electromagnetic waves of a certain band among the incident electromagnetic waves, while absorbing or reflecting electromagnetic waves of a certain band. For example, the conductive pattern (10) can selectively transmit, amplify, or block electromagnetic waves of a certain band among the electromagnetic waves incident on the surface of the electromagnetic wave transparent film.

[0048] For example, electromagnetic waves with high or ultra-high frequency bands, such as those used in 4G / 5G, have short wavelengths and are difficult to diffract, which can increase reflection and interference. Consequently, when passing through structures like walls and glass, electromagnetic waves experience increased loss and attenuation, potentially reducing signal efficiency and coverage.

[0049] The conductive pattern (10) can selectively transmit or reflect electromagnetic waves of a specific band by controlling the phase, direction of propagation, and refractive index of the incident electromagnetic waves. Therefore, transmission loss and attenuation can be prevented even in a high frequency band, and signal intensity can be increased and electromagnetic noise can be reduced in a desired frequency band.

[0050] The dummy pattern (20) can be placed within the hollow region (11) of the conductive pattern (10). The dummy pattern (20) can be electrically and physically separated from the electrode region (12). The thermal conductivity of the electromagnetic wave transparent film can be lowered and the insulation can be improved by the dummy pattern (20).

[0051] For example, a hollow region (11) may be formed within a conductive pattern (10) to increase the aperture ratio of the electromagnetic wave transparent film. As the aperture ratio increases, heat transfer through the hollow region (11) may increase, and the thermal resistance of the electromagnetic wave transparent film may decrease. In this case, the insulation properties of the electromagnetic wave transparent film may deteriorate.

[0052] According to exemplary embodiments, the dummy pattern (20) can block or impede heat transfer and radiation through the hollow region (11), thereby reducing thermal energy passing through the electromagnetic wave transparent film. Accordingly, the conductive pattern can have high thermal resistance and low thermal transmittance, and the thermal insulation properties of the electromagnetic wave transparent film can be improved.

[0053] The aperture ratio of the dummy pattern (20) may be 50% or less. The aperture ratio can be calculated as a percentage of the total area of ​​the dummy pattern (20) to the total area of ​​the hollow region (11) when observed in a planar direction.

[0054] When the aperture ratio of the dummy pattern (20) is 50% or less, the thermal energy passing through the conductive pattern (10) can be reduced, and the electromagnetic wave transparent film can have high reflectivity characteristics for radiation in the infrared or far infrared region. Accordingly, the transmittance for electromagnetic waves can be improved while the insulation can be improved.

[0055] In some embodiments, the aperture ratio of the dummy pattern (20) may be 40% or less, preferably 30% or less, and more preferably 20% or less. Within this range, the electromagnetic wave transparent film may have high selective electromagnetic wave transparency while also improving insulation properties.

[0056] In some embodiments, the aperture ratio of the dummy pattern (20) may be 5% or more, preferably 10% or more. Accordingly, selective electromagnetic wave transmittance may be improved while blocking heat conduction and radiation.

[0057] Figure 2 is a schematic plan view that enlarges area A of Figure 1.

[0058] Referring to FIG. 2, the dummy pattern (20) can be physically separated from the electrode region (12) of the conductive pattern (10) by a separation region (18). The dummy pattern (20) can include a plurality of sub-patterns (22).

[0059] The sub-patterns (22) may be physically spaced apart from each other. For example, the sub-patterns (22) may have an island pattern shape. This can prevent changes in capacitance or inductance due to electrical connection between the sub-patterns (22).

[0060] The sub-patterns (22) can be arranged periodically and repeatedly within the hollow region (11). The sub-patterns (22) are periodically arranged around the electrode region (12) of the conductive pattern (10), so that the reflectivity and refractive index of the electromagnetic wave transparent film can be uniformized or leveled. Accordingly, visibility due to optical deviation can be suppressed. In addition, the aperture ratio of the hollow region (11) is reduced by the sub-patterns (22), so that the insulation properties of the electromagnetic wave transparent film can be improved.

[0061] According to exemplary embodiments, the sub-pattern (22) may have a circular or polygonal shape such as a square, pentagon, or hexagon. For example, the sub-pattern (22) may be a solid pattern having a circular or polygonal shape.

[0062] In some embodiments, the period (P) of the sub-patterns (22) may be 100 μm or less. The period (P) of the sub-patterns (22) may be the shortest distance between the centers of adjacent sub-patterns (22). Accordingly, coupling between the sub-patterns (22) can be suppressed, and electromagnetic wave transmission loss and noise generation can be suppressed. Accordingly, the selective transmission characteristics of electromagnetic waves in a desired band can be improved.

[0063] In one embodiment, the period (P) of the sub-patterns (22) may be 200 μm or less, 150 μm or less, 100 μm or less, and preferably 50 μm or less. In one embodiment, the period (P) of the sub-patterns (22) may be 8 μm or more, 10 μm or more, or 12 μm or more. Within the above range, the electromagnetic wave transmittance and thermal insulation of the electromagnetic wave transparent film may be improved together.

[0064] In some embodiments, the ratio of the width (W2) of the sub-pattern (22) to the width (W1) of the conductive pattern (10) may be 0.1 or less. Within the above range, interference and distortion of the dummy pattern (20) with the electrical characteristics of the conductive pattern (10) can be prevented. Accordingly, the selective transmission characteristics of electromagnetic waves in a desired frequency band can be improved while also enhancing the insulation properties.

[0065] In one embodiment, the ratio of the width (W2) of the sub-pattern (22) to the width (W1) of the conductive pattern (10) may be 0.09 or less, 0.08 or less, or 0.05 or less. In one embodiment, the ratio of the width (W2) of the sub-pattern (22) to the width (W1) of the conductive pattern (10) may be 0.001 or more, 0.005 or more, or 0.01 or more.

[0066] The width of the conductive pattern (10) and the width of the sub-pattern (22) can be adjusted according to the frequency wavelength of the desired band. For example, the width of the conductive pattern (10) can be adjusted to satisfy Equation 1.

[0067] [Formula 1]

[0068] λ / 20≤W1≤λ / 2

[0069] In Equation 1, W1 is the width of the conductive pattern (10), and λ may be the wavelength of an electromagnetic wave having a target transmission frequency band.

[0070] In one embodiment, the spacing (G2) between adjacent sub-patterns (22) may be smaller than the width (W2) of the sub-patterns (22). Accordingly, the visibility of the conductive pattern (10) and the dummy pattern (20) may be improved, while the insulation of the electromagnetic wave transparent film may be enhanced.

[0071] In some embodiments, the spacing (G2) between the sub-patterns (22) may be 1 μm to 10 μm. Within this range, electromagnetic wave transmittance and optical properties may be improved, while thermal insulation may be further enhanced. In one embodiment, the spacing (G2) between the sub-patterns (22) may be 1 μm to 8 μm, or 2 μm to 6 μm.

[0072] In one embodiment, the distance (G1) between the electrode region (12) of the conductive pattern (10) and the dummy pattern (20) may be about 1 μm to 10 μm, or about 3 μm to 10 μm. Within the above range, the visibility of the conductive pattern (10) can be suppressed while ensuring insulation between the dummy pattern (20) and the conductive pattern (10).

[0073] In some embodiments, the sub-patterns (22) may be arranged in the row direction and the column direction. For example, a plurality of sub-patterns (22) may be arranged in the row direction to define a sub-pattern row, and a plurality of sub-patterns (22) may be arranged in the column direction to define a sub-pattern column.

[0074] In one embodiment, the plurality of sub-pattern rows may be arranged in the column direction. In one embodiment, the plurality of sub-pattern columns may be arranged in the row direction.

[0075] The spacing area between the sub-patterns (22) may have a grid shape. For example, spacing lines extending in the row direction and spacing lines extending in the column direction may be formed by the sub-pattern rows and sub-pattern columns.

[0076] In one embodiment, the hollow region (11) of the conductive pattern (10) may have a linear shape, a circular shape, a polygonal shape (e.g., a square, a pentagon, a hexagon, an octagon, etc.), a ring shape, or a cross shape. The user can appropriately adjust the shape of the hollow region (11) according to various purposes and target effects. For example, the electromagnetic characteristics of the conductive pattern (10) can be adjusted by the shape, area, size, etc. of the hollow region (11).

[0077] In some embodiments, the conductive pattern (10) may have a ring shape or a closed-loop shape. A hollow region may be formed at the center of the ring shape or the closed-loop shape.

[0078] Fig. 3 is a schematic plan view showing a conductive pattern (10) according to exemplary embodiments. For convenience of explanation, the illustration of the dummy pattern (20) is omitted in Fig. 3.

[0079] Referring to FIG. 3, the conductive pattern (10) may include a first pattern (14) and a second pattern (16) that are physically spaced from each other. The hollow region (11) may be defined as a region between the first pattern (14) and the second pattern (16).

[0080] In one embodiment, the first pattern (14) may be formed around the edge of the second pattern (16) with the second pattern (16) as the center. For example, the first pattern (14) may have a shape that surrounds the second pattern (16).

[0081] The transmission and reflection characteristics of electromagnetic waves incident on the conductive pattern (10) can be controlled by the first pattern (14) and the second pattern (16). Accordingly, the transmittance for electromagnetic waves in a desired band can be improved, or electromagnetic waves in a cutoff frequency band can be eliminated or attenuated by the conductive pattern (10).

[0082] In some embodiments, the first pattern (14) may have a ring shape or a closed loop shape. The outer border of the first pattern (14) may have a circular or polygonal shape such as a square or hexagon. For example, the first pattern (14) may include a border pattern having a circular or polygonal ring shape.

[0083] In one embodiment, the conductive pattern (10) may include a corner pattern (15) protruding from the first pattern (14) toward the center of the first pattern (14). The corner pattern (15) may be integrally connected with the first pattern (14).

[0084] The second pattern (16) may be arranged within the first pattern (14) when observed in a planar direction. For example, the second pattern (16) may have an independent island pattern shape arranged at the center of the ring shape.

[0085] The second pattern (16) is arranged within the first pattern (14), so that the overall aperture ratio of the conductive pattern (10) can be reduced. Accordingly, the conductive pattern (10) can have low thermal conductivity and high thermal resistance.

[0086] In some embodiments, the second pattern (16) may have a circular or polygonal shape. In one embodiment, the shape of the second pattern (16) may be adjusted depending on the frequency of the electromagnetic wave to be transmitted or shielded.

[0087] In one embodiment, the outer border of the first pattern (14) and the outer border of the second pattern (16) may have the same shape or appearance. For example, if the outer border of the first pattern (14) has a square shape, the outer border of the second pattern (16) may also have a square shape.

[0088] In one embodiment, a hollow region may also be formed within the second pattern (16). For example, the second pattern (16) may also have a circular or polygonal ring shape, and a slit may be formed within the second pattern (16).

[0089] In some embodiments, when observed in a planar direction, the area of ​​the electrode region (12) of the conductive pattern (10) may be larger than the area of ​​the dummy pattern (20). Accordingly, the thermal resistance and electromagnetic wave transmittance of the electromagnetic wave transparent film may be improved together.

[0090] In one embodiment, when observed in a planar direction, the area of ​​the electrode region (12) may be larger than the area of ​​the hollow region (11). The area of ​​the hollow region (11) may be 50% or less of the total area of ​​the conductive pattern (10), for example, 5% to 50%, 5% to 40%, or 10% to 30%.

[0091] In some embodiments, the electrode region (12) and the dummy pattern (20) of the conductive pattern (10) may include a solid structure. Accordingly, the overall aperture ratio of the electromagnetic wave transparent film may be reduced, thereby lowering the thermal conductivity and thermal transmittance, and improving the insulation.

[0092] According to exemplary embodiments, the conductive pattern (10) and / or the dummy pattern (20) may include a metal, an alloy, a metal oxide, or a transparent conductive oxide.

[0093] For example, the conductive pattern (10) and / or the dummy pattern (20) may include silver (Ag), gold (Au), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd), chromium (Cr), titanium (Ti), tungsten (W), niobium (Nb), tantalum (Ta), vanadium (V), iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), zinc (Zn), tin (Sn), molybdenum (Mo), calcium (Ca), or an alloy containing at least one of these. These may be used alone or in combination of two or more.

[0094] In one embodiment, the conductive pattern (10) may include silver (Ag) or a silver alloy (e.g., a silver-palladium-copper (APC) alloy), or copper (Cu) or a copper alloy (e.g., a copper-calcium (CuCa) alloy).

[0095] In some embodiments, the conductive pattern (10) and the dummy pattern (20) may include a transparent conductive oxide. Accordingly, for example, even if the conductive pattern (10) and the dummy pattern (20) have a solid structure, the electromagnetic wave transmission loss and optical properties can be improved. Accordingly, the visibility, radio wave transmittance, and thermal insulation properties of the electromagnetic wave transparent film can be further improved.

[0096] The transparent conductive oxide may include indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), aluminum zinc oxide (AZO), zinc oxide (ZnOx), indium oxide (InOx), tin oxide (SnOx), cadmium tin oxide (CTO), gallium-doped zinc oxide (GZO), zinc tin oxide (ZTO), indium gallium oxide (IGO), and the like.

[0097] In some embodiments, the conductive pattern (10) and / or the dummy pattern (20) may include a laminated structure of a transparent conductive oxide layer and a metal layer, for example, a two-layer structure of a transparent conductive oxide layer-metal layer, or a three-layer structure of a transparent conductive oxide layer-metal layer-transparent conductive oxide layer.

[0098] In one embodiment, the conductive pattern (10) and / or the dummy pattern (20) may include a metamaterial. The electromagnetic wave transmittance, refractive index, incidence angle, and frequency band can be controlled by the metamaterial.

[0099] FIG. 4 is a schematic plan view showing an electromagnetic wave transparent film according to exemplary embodiments.

[0100] Referring to Fig. 4, one unit cell (C) can be defined by a conductive pattern (10) and a dummy pattern (20). A plurality of the unit cells (C) can be arranged adjacent to each other and repeatedly.

[0101] The unit cells (C) can be arranged periodically to enhance the selective transmission characteristics for electromagnetic waves of a specific band. For example, capacitance or inductance is induced by conductive patterns (10) arranged at a regular period, and the electromagnetic wave transparent film can resonate at a frequency having a specific impedance. Therefore, the frequency selectivity of the electromagnetic wave transparent film can be further enhanced.

[0102] In one embodiment, adjacent unit cells (C) may be in contact with each other. For example, the unit cells (C) may be formed integrally. In one embodiment, the unit cells (C) may be arranged so as to be physically spaced from each other.

[0103] The electromagnetic properties of the electromagnetic wave transparent film can be controlled by the arrangement of the unit cells (C). For example, the shape, arrangement period, and spacing of the unit cells (C) can be designed or controlled by considering the target frequency band to be transmitted, the direction of electromagnetic wave propagation, or the transmittance and reflectance of infrared, ultraviolet, and visible light, etc.

[0104] The electromagnetic wave transparent film may further include a substrate (30). A conductive pattern (10) and a dummy pattern (20) may be formed on the substrate (30).

[0105] The substrate (30) may include, for example, a transparent resin material. For example, the substrate (30) may include a polyester resin such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, or polybutylene terephthalate; a cellulose resin such as diacetyl cellulose or triacetyl cellulose; a polycarbonate resin; an acrylic resin such as polymethyl (meth)acrylate or polyethyl (meth)acrylate; a styrene resin such as polystyrene or an acrylonitrile-styrene copolymer; a polyolefin resin such as polyethylene, polypropylene, a polyolefin having a cyclo- or norbornene structure, or an ethylene-propylene copolymer; a vinyl chloride resin; an amide resin such as nylon or an aromatic polyamide; an imide resin; a polyethersulfone resin; a sulfone resin; a polyetheretherketone resin; a sulfated polyphenylene resin; a vinyl alcohol resin; It may include vinylidene chloride resin; vinyl butyral resin; allylate resin; polyoxymethylene resin; epoxy resin; urethane or acrylic urethane resin; silicone resin, etc. These may be used alone or in combination of two or more.

[0106] In one embodiment, an adhesive film such as an optically clear adhesive (OCA), an optically clear resin (OCR), or the like may be included in the substrate (30).

[0107] In some embodiments, the substrate (30) may include an inorganic insulating material such as silicon oxide, silicon nitride, silicon oxynitride, or the like.

[0108] According to one embodiment, the object to which the electromagnetic wave transparent film is attached may be provided as a substrate (30). For example, a glass substrate such as a building exterior wall, a window, an appliance, or an automobile window may be provided as the substrate (30) of the electromagnetic wave transparent film.

[0109] In some embodiments, the dielectric constant of the substrate (30) can be adjusted to a range of about 2 to 12.

[0110] In some embodiments, the first pattern (14) and the second pattern (16) may be arranged at the same level or in the same layer on the substrate (30). In some embodiments, the conductive pattern (10) and the dummy pattern (20) may also be arranged at the same level or in the same layer on the substrate (30).

[0111] The electromagnetic wave transparent film can be provided as an electromagnetic wave transparent device, an electromagnetic wave amplifier, a resonator, a filter, a frequency selective surface (FSS), a reconfigurable intelligent surface (RIS), etc.

[0112] In some embodiments, the electromagnetic wave transparent film can be applied to wireless communication systems, image display devices, electronic devices, buildings, aircraft, vehicles, etc. For example, the electromagnetic wave transparent film can be attached to windows, home appliances, vehicle windows, building exterior walls, etc. to selectively absorb electromagnetic waves while blocking internal and external heat flow.

[0113] FIG. 5 is a schematic cross-sectional view showing an electromagnetic wave transparent film according to exemplary embodiments.

[0114] Referring to FIG. 5, the electromagnetic wave transparent film may include a substrate (90) and an electrode pattern layer (100) disposed on the substrate (90).

[0115] The electrode pattern layer (100) may include an electrode layer (130) including the conductive pattern and dummy pattern described above.

[0116] The electrode layer (130) may include the metal, alloy, metal oxide, or transparent conductive oxide described above. In one embodiment, the electrode layer (130) may include a solid structure.

[0117] In one embodiment, the electrode pattern layer (100) may further include a lower insulating layer (120) disposed between the substrate (90) and the electrode layer (130) and / or an upper insulating layer (140) disposed on the electrode layer (130).

[0118] The mechanical properties and stability, such as crack resistance, of the electrode pattern layer (100) can be improved by the lower insulating layer (120). The oxidation and corrosion of the metal or metal oxide included in the electrode pattern layer (100) can be prevented by the upper insulating layer (140).

[0119] In one embodiment, the lower insulating layer (120) and the upper insulating layer ((140)) may include an organic insulating material such as an epoxy resin, an acrylic resin, an imide-based resin, or the like, or an inorganic insulating material such as silicon oxide, silicon nitride, silicon oxynitride, or the like.

[0120] In one embodiment, a transparent film may be provided as the lower insulating layer (120) and the upper insulating layer (140). For example, the transparent film may include the transparent resin material described above.

[0121] In some embodiments, the dielectric constants of the lower insulating layer (120) and the upper insulating layer (140) can be adjusted to a range of about 2 to 12, respectively. When the dielectric constant exceeds about 12, reflection, refraction, and phase change of electromagnetic waves may increase, thereby reducing electromagnetic wave transmittance.

[0122] According to exemplary embodiments, the electrode pattern layer (100) may further include an adhesive layer (150). The electrode pattern layer (100) may be attached to a substrate (90) by the adhesive layer (150). In some embodiments, the adhesive layer (150) may include an adhesive film such as an optically clear adhesive (OCA), an optically clear resin (OCR), or the like.

[0123] The window structure according to embodiments of the present invention may include the conductive pattern or the electromagnetic wave transparent film described above.

[0124] Figures 6 and 7 are schematic cross-sectional views each showing a window structure according to exemplary embodiments.

[0125] Referring to FIGS. 6 and 7, the window structure may include a substrate (90) and an electrode pattern layer (100) disposed on the substrate (90).

[0126] The location and size of the region where the electrode pattern layer (100) is formed can be designed or controlled by considering the surrounding environment or the operating conditions of the antenna. For example, indoor and outdoor temperature, humidity, thickness and permittivity of the substrate, surrounding structures, permittivity and physical properties of the structures, height and signal transmission path of the window structure, frequency of electromagnetic waves, angle of incidence, and transmission distance, etc. can be considered.

[0127] The electromagnetic wave transmittance of a specific band among electromagnetic waves incident on the window structure may be increased by the electrode pattern layer (100). In addition, the electrode pattern layer (100) may block thermal energy such as thermal radiation passing through the window structure, thereby improving insulation.

[0128] In some embodiments, the window structure may further include a lower substrate (92). For example, the window structure may have a pair glass form.

[0129] In one embodiment, an air layer (200) may be formed between the substrate (90) and the lower substrate (92). The air layer (200) may include air or argon (Ar) gas. The air layer (200) may further suppress heat flow through conduction and convection.

[0130] An electrode pattern layer (100) may be formed on the substrate (90) or the lower substrate (92). In one embodiment, the electrode pattern layer (100) may be formed on both the substrate (90) and the lower substrate (92).

[0131] Referring to FIG. 6, the electrode pattern layer (100) may be formed on the opposite side of the surface of the substrate (90) that faces the air layer (200). For example, the electrode pattern layer (100) may be formed on the surface of the substrate (90) onto which electromagnetic waves are incident.

[0132] Referring to Fig. 7, the electrode pattern layer (100) may be formed on one surface facing the air layer of the substrate. For example, the electrode pattern layer (100) may be formed on the opposite surface of the surface of the substrate (90) onto which electromagnetic waves are incident.

[0133] The above window structure can be applied to various structures and objects, such as windows of public transportation such as buses and subways, buildings, windows, vehicles, decorative sculptures, and guidance signs (e.g., directional signs, emergency exit signs, emergency lights), etc. The above window structure can improve insulation and energy efficiency, and increase signal efficiency by antennas or radars.

[0134]

[0135] Hereinafter, preferred embodiments are presented to help understand the present invention, but these embodiments are only illustrative of the present invention and do not limit the scope of the appended claims. It is obvious to those skilled in the art that various changes and modifications to the embodiments are possible within the scope and technical idea of ​​the present invention, and it is also natural that such changes and modifications fall within the scope of the appended claims.

[0136]

[0137] Experimental example

[0138] Example

[0139] A glass substrate with an electromagnetic wave transparent film attached to the window structure was used. Specifically, an electrode pattern layer including a conductive pattern and a dummy pattern was formed on a glass substrate (thickness 4.8 μm) as shown in Fig. 1. The electrode pattern layer was formed in a three-layer structure of a lower insulating layer - an electrode layer (IZO / APC / IZO) - an upper insulating layer. The electrode pattern layer was bonded to the glass substrate using OCA (thickness 5 μm).

[0140] The dummy pattern was formed to have the shape of Fig. 2. The period (P) of the sub-pattern was set to 13.9 μm, the width (W2) of the sub-pattern was set to 9.4 μm, and the spacing between sub-patterns (G2) was set to 4.5 μm. The dummy pattern had an aperture ratio of 10%.

[0141] Comparative Example 1

[0142] A 4.8t thick glass substrate was used as the window structure.

[0143] Comparative Example 2

[0144] Low-emissivity glass was used as the window structure. The low-emissivity glass was formed by forming a NiCr / Ag / NiCr metal film on a 4.8-ton thick glass substrate. The metal film was formed to have a solid structure.

[0145] Comparative Example 3

[0146] A window structure was manufactured in the same manner as in the example except that no dummy pattern was formed.

[0147] Comparative Example 4

[0148] A window structure was manufactured in the same manner as in the example, except that the aperture ratio of the dummy pattern was adjusted to 70%. Specifically, the dummy pattern was formed as a mesh structure defined by intersecting conductive lines, with the period of the conductive lines being 50 μm, the width being 10 μm, and the spacing between the conductive lines being 10 μm.

[0149]

[0150] Visibility assessment

[0151] The visibility of the challenge pattern and dummy pattern was evaluated by visually observing the window structure.

[0152] <Evaluation Criteria>

[0153] ◎: Pattern is not visible from all directions.

[0154] △: Pattern is recognized in a specific direction

[0155] ×: The pattern is clearly recognized

[0156]

[0157] Radio transmission loss assessment

[0158] The radio wave transmission through the window structure was evaluated. The radio wave transmission loss was measured as a relative value to the transmission in air in the frequency range of 27 GHz to 29 GHz.

[0159] <Evaluation Criteria>

[0160] ◎: Radio transmission loss -5dB or more

[0161] ○: Radio transmission loss less than -5dB and more than -30dB

[0162] ×: Radio transmission loss less than -30dB

[0163]

[0164] FIG. 8 is a graph showing the electromagnetic wave transmission loss of window structures according to Examples, Comparative Example 1, Comparative Example 2, and Comparative Example 4.

[0165]

[0166] Insulation evaluation

[0167] The thermal emissivity of the window structure was measured using an infrared spectroscopy (FT-IR) according to KS L 2514. The thermal transmittance of the window structure was measured using the measured emissivity according to KS L 2003:2013.

[0168] <Evaluation Criteria>

[0169] ◎: Thermal emissivity less than 0.1 and thermal transmittance 3.5 W / m 2 Less than K

[0170] ○: Thermal emissivity 0.1 to 0.3, and thermal transmittance 3.5 W / m 2 K to 4.5 W / m 2 K

[0171] △: Thermal emissivity exceeding 0.3 and less than 0.8, and thermal transmittance of 4.5 W / m 2 K exceeds 5.5 W / m 2 Less than K

[0172] ×: Thermal emissivity of 0.8 or more, and thermal transmittance of 5.5 W / m 2 K or higher

[0173]

[0174] The evaluation results are shown in Table 1 below.

[0175]

[0176] Visibility Radio wave transmittance Insulation Example ◎◎○Comparative example 1◎○×Comparative example 2◎×◎Comparative example 3△◎△Comparative example 4△◎△

[0177] Referring to Table 1 and FIG. 8, the window structure of the embodiment had high electromagnetic wave transparency in the ultra-high frequency band and low thermal emissivity and thermal transmittance.

[0178] However, in the comparative examples, the radio wave transmittance, visibility, or insulation of the window structure was reduced.

[0179] In Comparative Example 1, a glass substrate was used as the window structure, resulting in poor insulation and relatively high radio wave transmission loss. In Comparative Example 2, low-e glass was used as the window structure, resulting in a high radio wave transmission loss of less than -30 dB.

[0180] In Comparative Examples 3 and 4, the visibility of the pattern was reduced, and the window structure had high thermal emissivity and thermal transmittance.

Claims

1. Substrate; A conductive pattern disposed on the substrate and including an electrode region and a hollow region; and An electromagnetic wave transparent film comprising a dummy pattern arranged spaced apart from the electrode region within the hollow region on the substrate and having an opening ratio of 50% or less.

2. An electromagnetic wave transparent film according to claim 1, wherein the dummy pattern includes a plurality of sub-patterns arranged periodically.

3. An electromagnetic wave transparent film according to claim 2, wherein the sub-patterns have an island pattern shape that is physically separated from each other.

4. An electromagnetic wave transparent film according to claim 2, wherein each of the sub-patterns has a circular or polygonal shape.

5. An electromagnetic wave transparent film according to claim 2, wherein a ratio of the width of the sub-pattern to the width of the conductive pattern is 0.1 or less.

6. An electromagnetic wave transparent film according to claim 2, wherein the width of the sub-patterns is greater than the spacing between adjacent sub-patterns.

7. An electromagnetic wave transparent film according to claim 1, wherein the aperture ratio of the dummy pattern is 10% or more.

8. An electromagnetic wave transparent film according to claim 1, wherein the conductive pattern includes a ring shape or a loop shape.

9. An electromagnetic wave transparent film according to claim 1, wherein the conductive pattern includes a first pattern and a second pattern that are physically spaced apart from each other, and the hollow region is defined as a region between the first pattern and the second pattern.

10. An electromagnetic wave transparent film according to claim 9, wherein the first pattern surrounds the edge of the second pattern with the second pattern as the center in the plane direction.

11. An electromagnetic wave transparent film according to claim 10, wherein the first pattern has a circular or polygonal ring shape in the plane direction.

12. An electromagnetic wave transparent film according to claim 10, wherein the second pattern has a circular or polygonal island pattern shape.

13. An electromagnetic wave transparent film according to claim 1, wherein the area of ​​the electrode region is larger than the area of ​​the dummy pattern when observed in a planar direction.

14. An electromagnetic wave transparent film according to claim 1, wherein the electrode region of the conductive pattern and the dummy pattern have a solid structure.

15. An electromagnetic wave transparent film according to claim 1, wherein one unit cell is defined by the conductive pattern and the dummy pattern, and a plurality of the unit cells are arranged adjacent to each other and repeatedly on the substrate.

16. An electromagnetic wave transparent film according to claim 1, wherein the conductive pattern and the dummy pattern include a transparent conductive oxide.

17. A window structure comprising an electromagnetic wave transparent film according to claim 1.

18. A window structure according to claim 17, further comprising a lower substrate disposed under the substrate, and an air layer formed between the substrate and the lower substrate.

Images