Electromagnetic wave absorbing member

Abstract

An electromagnetic wave absorbing member (1) has a resistance layer (10), a spacer layer (20), and a reflection layer (30) which are stacked in this order, the resistance layer (10) has a conductive body pattern (11) which is embedded on the side of the opposite face (20a) of the face (20b) of the spacer layer (20) which is opposite to the reflection layer (30).

Description

Technical Field

[0001] This invention relates to electromagnetic wave absorbing components.

[0002] This application claims priority based on Japanese Patent Application No. 2024-025870 filed in Japan on February 22, 2024, the contents of which are incorporated herein by reference. Background Technology

[0003] A sheet-like electromagnetic wave absorbing component is known to selectively absorb electromagnetic waves of a specified frequency. For example, the electromagnetic wave absorbing component includes a first frequency-selective shielding layer and a second frequency-selective shielding layer. In such an electromagnetic wave absorbing component, by means of the fine line pattern of the FSS (Frequency Selective Surface) elements formed on the first and second frequency-selective shielding layers, each layer absorbs electromagnetic waves of a specified frequency, and as a whole, selectively shields two electromagnetic waves of different frequencies.

[0004] Electromagnetic wave absorbing components are required to fit tightly against curved surfaces when applied, depending on their intended use. Therefore, these components must maintain sufficient electromagnetic wave absorption and flexural rigidity even when tightly fitted against curved surfaces.

[0005] Patent Document 1 describes an electromagnetic wave shielding sheet that combines transparency without impairing the visibility of the display screen with a frame portion of a metal layer having an exposed surface for grounding. Specifically, the electromagnetic wave shielding sheet is characterized by comprising: a transparent substrate; a mesh-like metal layer disposed on one side of the transparent substrate through a transparent adhesive layer, the metal layer having: a mesh portion having a plurality of openings and lines surrounding the openings; a frame portion disposed around the periphery of the mesh portion, the surface of the frame portion having exposed metal on the side opposite to the adhesive layer, and a transparent ionizing radiation-curing resin layer embedded in the openings.

[0006] Patent Document 2 describes a vehicle-mounted antenna that allows for easy placement of multiple antennas without compromising the design of the vehicle. Specifically, it describes a vehicle-mounted dielectric antenna characterized by comprising: a vehicle component, which is a resin component having a plate-like portion and serving as a dielectric constituting the vehicle shell; an antenna pattern formed on the outer surface of the plate-like portion of the vehicle component; a grounding conductor layer formed on the inner surface of the plate-like portion of the vehicle component, on the back side of the antenna pattern; a transceiver unit disposed on the back side of the vehicle component for supplying power to the antenna pattern and / or acquiring signals from the antenna pattern; and a cover layer formed by coating the outer surface of the vehicle component to cover the antenna pattern.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: International Publication No. 2005 / 069713

[0010] Patent Document 2: Japanese Patent No. 6604359 Summary of the Invention

[0011] The technical problem that the invention aims to solve

[0012] However, the electromagnetic wave shielding sheet described in Patent Document 1 and the dielectric antenna described in Patent Document 2 have problems with insufficient electromagnetic wave absorption and bending rigidity.

[0013] The present invention was made in view of the above circumstances, and its object is to provide an electromagnetic wave absorbing component with excellent electromagnetic wave absorption and bending rigidity.

[0014] Technical solutions for solving technical problems

[0015] The present invention provides the following electromagnetic wave absorbing component.

[0016] [1] An electromagnetic wave absorbing component has a resistive layer, a spacer layer and a reflective layer, wherein the resistive layer, the spacer layer and the reflective layer are stacked in sequence, the resistive layer has a conductive pattern, and the conductive pattern is embedded in the spacer layer on the opposite side of the surface opposite to the reflective layer.

[0017] [2] According to the electromagnetic wave absorbing component described in [1], the relative permittivity of the spacer layer is 5 or more.

[0018] Invention Effects

[0019] According to the present invention, an electromagnetic wave absorbing component with excellent electromagnetic wave absorption and bending stiffness can be provided. Attached Figure Description

[0020] Figure 1 The electromagnetic wave absorbing component of one embodiment of the present invention is schematically shown in a cross-sectional view along the thickness of the surface.

[0021] Figure 2 This is a top view showing an example of the resistive layer constituting an electromagnetic wave absorbing component according to an embodiment of the present invention.

[0022] Figure 3 The electromagnetic wave absorbing component of one embodiment of the present invention is schematically shown in a cross-sectional view along the thickness of the surface.

[0023] Figure 4This is a schematic diagram illustrating a method for measuring the bending stiffness of an electromagnetic wave absorbing component according to an embodiment of the present invention. Detailed Implementation

[0024] An embodiment of the electromagnetic wave absorbing component of the present invention will be described.

[0025] Furthermore, this embodiment is specifically described in order to better understand the spirit of the invention, and unless otherwise specified, it is not intended to limit the invention.

[0026] In this specification, "conductor pattern" is a collection of geometric units, referring to an object that selectively absorbs electromagnetic waves of a certain frequency. "Conductor pattern" can also be said to have the same function as a so-called antenna.

[0027] In this specification, "electromagnetic waves in the millimeter wave region" refers to electromagnetic waves with wavelengths of 1 mm to 10 mm. "Electromagnetic waves in the millimeter wave region" can also be described as electromagnetic waves with frequencies of 30 GHz to 300 GHz.

[0028] In this specification, the "~" indicating a numerical range means that the values ​​before and after it are included as the lower limit and upper limit.

[0029] [Electromagnetic wave absorption component]

[0030] (First Implementation)

[0031] Figure 1 The electromagnetic wave absorbing component of one embodiment of the present invention is schematically shown in a cross-sectional view along the thickness of the surface.

[0032] like Figure 1 As shown, the electromagnetic wave absorbing component 1 of this embodiment has a resistive layer 10, a spacer layer 20, and a reflective layer 30. Furthermore, the resistive layer 10, the spacer layer 20, and the reflective layer 30 are stacked sequentially.

[0033] The resistive layer 10 has a conductive pattern 11. The conductive pattern 11 is embedded in the spacer layer 20 on the opposite side (one side (surface)) 20a of the surface (other side (back side)) 20b opposite to the reflective layer 30. Furthermore, the outermost surface (upper surface) 10a of the resistive layer 10 is disposed on the same surface as one side 20a of the spacer layer 20. The spacer layer 20 is disposed between the resistive layer 10 and the reflective layer 30. That is, the resistive layer 10 and the reflective layer 30 are stacked via the spacer layer 20.

[0034] The resistive layer 10 is a single layer. In the case where the resistive layer 10 is a single layer, the resistive layer 10 is made of the same material as the conductive pattern 11 described later.

[0035] "Resistive layer"

[0036] The resistive layer 10 is composed of a frequency selective surface (FSS). A frequency selective surface is a surface that can block or allow electromagnetic waves of a specific frequency to pass through by forming a continuous structure with a shape below the wavelength by conductive components or the like.

[0037] Figure 2 This is a top view showing an example of the resistive layer constituting an electromagnetic wave absorbing component according to an embodiment of the present invention. For example... Figure 2 As shown, the resistive layer 10 has a conductive pattern 11. The conductive pattern 11 is, for example, composed of a first conductive pattern 41, a second conductive pattern 42, and a third conductive pattern 43.

[0038] The thicknesses of the first conductive pattern 41, the second conductive pattern 42, and the third conductive pattern 43 are not particularly limited. These thicknesses can be arbitrarily varied according to desired characteristics. Furthermore, these three thicknesses can be the same or different; however, considering productivity, it is preferable that they are the same. Additionally, from the viewpoint of balancing electromagnetic wave absorption and surface following, the thicknesses of the first conductive pattern 41, the second conductive pattern 42, and the third conductive pattern 43 are preferably 10 nm to 300 μm, more preferably 40 nm to 1 μm, and particularly preferably 80 nm to 400 nm.

[0039] (First conductor pattern)

[0040] like Figure 2 As shown, the first conductive pattern 41 is composed of multiple first units u1. The first units u1 are geometric shapes.

[0041] That is, the first conductor pattern 41 can also be said to be a collection of the first unit u1 as a geometric figure.

[0042] The first unit u1 functions as an antenna. The first conductor pattern 41 can also be, for example, a thin line pattern of an FSS element.

[0043] In the first conductor pattern 41, a plurality of first arrangements R1 are formed, wherein the first arrangement R1 is a plurality of first units u1 along Figure 2 The first conductive pattern 41 is formed by arranging multiple first arrangements R1 in the direction indicated by the double arrow P. Alternatively, it can be said that the first conductive pattern 41 has multiple first arrangements R1 at predetermined intervals along the direction indicated by the double arrow P on the spacer layer 20.

[0044] There are no particular restrictions on the spacing between multiple first permutations R1. The spacing between the first permutations R1 can be regular or irregular.

[0045] like Figure 2 As shown, the first unit u1 has a cross-shaped structure that is symmetrical from top to bottom and left to right. Specifically, the first unit u1 has a cross-shaped portion S1 and four end portions T1. The cross-shaped portion S1 is composed of... Figure 2 It consists of a straight line portion parallel to the x-axis and a straight line portion parallel to the y-axis. Each end T1 of the straight line is connected to the two ends of the straight line portion parallel to the x-axis and the two ends of the straight line portion parallel to the y-axis, respectively, in a manner orthogonal to each straight line portion.

[0046] By adjusting the x-axis length of the first unit u1 and the x-axis length of each of the four end units T1, the electromagnetic wave absorption characteristics of the first unit u1, which functions as an antenna, can be adjusted. The same applies to the y-axis direction, which also allows for adjustment of the electromagnetic wave absorption characteristics.

[0047] However, the shape of the first unit is not limited to a cross shape. The shape of the first unit is not particularly limited as long as the frequency at which the absorption of electromagnetic waves by the first conductor pattern 41 exhibits a maximum value is A [GHz].

[0048] For example, the shapes of the first unit of a graphic can include circles, rings, straight lines, squares, polygons, H-shapes, Y-shapes, V-shapes, etc.

[0049] In the resistive layer 10, the shapes of the plurality of first units u1 are identical. However, the shapes of the plurality of first units u1 may not be identical. In other embodiments of the invention, the shapes of the plurality of first units may be identical or different, as long as the absorption characteristics can be adjusted to the target frequency.

[0050] The first conductive pattern 41 improves the transmittance of electromagnetic waves at the following frequency A [GHz].

[0051] In the resistive layer 10 of this embodiment, the frequency value A is preferably 20GHz to 110GHz, more preferably 60GHz to 100GHz, even more preferably 65GHz to 95GHz, and particularly preferably 70GHz to 90GHz. If the frequency value A is within the above range, the obtained electromagnetic wave absorbing component 1 can absorb electromagnetic waves in the millimeter wave region and can be easily applied to automotive components, roadside components, building exterior wall materials, windows, communication equipment, radio telescopes, etc.

[0052] The material of the first unit u1 only needs to be able to adjust the absorption characteristics to the target frequency; there are no special restrictions.

[0053] Materials used as the first unit include, for example, fine metal wires, conductive films, and conductive paste fixing materials.

[0054] Examples of metallic materials include copper, aluminum, tungsten, iron, molybdenum, nickel, titanium, silver, gold, or alloys containing two or more of these metals (e.g., stainless steel, carbon steel and other steels, brass, phosphor bronze, zirconium copper alloy, beryllium copper, iron-nickel, nickel-chromium alloy, nickel-titanium, cantal alloy, Hastelloy alloy, rhenium-tungsten, etc.).

[0055] Metal oxides such as tin oxide (ITO) can be cited as materials for conductive thin films.

[0056] Materials used for conductive pastes include metal particles, carbon nanoparticles, and carbon fibers.

[0057] The spacing between the ends of the figure of the first unit u1 is not particularly limited, as long as the absorption characteristics can be adjusted to the target frequency.

[0058] For example, the spacing between the ends of the pattern that forms the first unit u1 can be all the same or different. However, it is easier to design a resistive layer that is not easily affected by the surrounding environment, and the accuracy of the frequency band of the transmitted electromagnetic waves is improved during manufacturing. Therefore, it is preferable that the spacing between the ends of the pattern that forms the first unit u1 is the same.

[0059] (Second conductor pattern)

[0060] like Figure 2 As shown, the second conductor pattern 42 is composed of multiple second units u2.

[0061] The second conductor pattern 42 is formed in the same way as the first conductor pattern 41.

[0062] The second conductive pattern 42 selectively allows electromagnetic waves with a frequency of B [GHz] that satisfies the following equation (1). The frequency value B [GHz] is the frequency at which the transmission amount of the electromagnetic wave through the second conductive pattern 42 reaches its maximum value. The frequency value B [GHz] satisfies the following equation (1).

[0063] 1.037×A≤B≤1.30×A……Equation (1)

[0064] As shown in equation (1) above, the second conductor pattern 42 allows electromagnetic waves with frequencies of 1.037 × Å [GHz] to 1.30 × Å [GHz] to pass through. Preferably, the second conductor pattern 42 allows electromagnetic waves with frequencies of 1.17 × Å [GHz] to 1.30 × Å [GHz] to pass through.

[0065] Because the second conductive pattern 42 allows electromagnetic waves with frequencies above 1.037 × Å [GHz] to pass through, the peak value of the electromagnetic wave transmission of the second conductive pattern 42 in frequency bands higher than Å [GHz] fully overlaps with the peak value of the electromagnetic wave transmission of the first conductive pattern 41. As a result, compared to the case where only the first conductive pattern 41 is present, the frequency band of electromagnetic waves that can be transmitted in the resistive layer 10 as a whole extends to a frequency band higher than Å [GHz].

[0066] Because the second conductive pattern 42 allows electromagnetic waves with frequencies below 1.30 × Å [GHz] to pass through, the frequency difference between the peak value of the electromagnetic wave transmitted by the second conductive pattern 42 and the peak value of the electromagnetic wave transmitted by the first conductive pattern 41 becomes smaller in frequency bands higher than Å [GHz]. As a result, the transmission of electromagnetic waves forming the entire resistive layer 10 becomes a single peak value with a maximum value.

[0067] Based on the above, the second conductor pattern 42 allows electromagnetic waves with frequencies of 1.037×A [GHz] to 1.30×A [GHz] to pass through, thus extending the transmission of electromagnetic waves that pass through the entire electromagnetic wave absorbing component 1 to the high-frequency band.

[0068] The material of the second unit constituting the second conductor pattern 42 can be any material that allows electromagnetic waves of B [GHz] to pass through, without any particular limitation, as long as the transmission characteristics can be adjusted to the target frequency, without any particular limitation.

[0069] The material of the second unit is described in the same way as the material of the first unit u1.

[0070] (Third conductor pattern)

[0071] like Figure 2 As shown, the third conductor pattern 43 is composed of multiple third units u3.

[0072] The third conductor pattern 43 is formed in the same way as the first conductor pattern 41.

[0073] The third conductor pattern 43 selectively allows electromagnetic waves with a frequency of C [GHz] that satisfies the following equation (2). The frequency value C [GHz] is the value of the frequency at which the transmission amount of the electromagnetic wave transmitted by the third conductor pattern 43 reaches its maximum. The frequency value C [GHz] satisfies the following equation (2).

[0074] 0.60×A≤C≤0.963×A……Equation (2)

[0075] As shown in equation (2) above, the third conductor pattern 43 allows electromagnetic waves with frequencies of 0.60×A [GHz] to 0.963×A [GHz] to pass through. Preferably, the third conductor pattern 43 allows electromagnetic waves with frequencies of 0.60×A [GHz] to 0.83×A [GHz] to pass through.

[0076] Because the third conductor pattern 43 allows electromagnetic waves with frequencies above 0.60 × Å [GHz] to pass through, the frequency difference between the peak value of the electromagnetic wave transmitted based on the third conductor pattern 43 and the peak value of the electromagnetic wave transmitted based on the first conductor pattern 41 decreases in frequency bands lower than Å [GHz]. As a result, the transmission of electromagnetic waves that form the entire transmission through the resistive layer 10 becomes a single peak value with a maximum value.

[0077] Because the third conductive pattern 43 allows electromagnetic waves with frequencies below 0.963 × Å [GHz] to pass through, the peak value of the electromagnetic wave transmission of the third conductive pattern 43 in the frequency band below Å [GHz] fully overlaps with the peak value of the electromagnetic wave transmission of the first conductive pattern 41. As a result, the frequency band of electromagnetic waves that the entire resistive layer 10 can transmit extends to the low-frequency side below Å [GHz] compared to a film having only the first conductive pattern 41.

[0078] As described above, the third conductive pattern 43 allows electromagnetic waves with frequencies of 0.60×A [GHz] to 0.963×A [GHz] to pass through, thus extending the transmission of electromagnetic waves that pass through the entire resistive layer 10 to the low-frequency band.

[0079] The material of the third unit u3 constituting the third conductor pattern 43 can be any material that allows electromagnetic waves of C[GHz] to pass through, without any particular limitation. As long as the absorption characteristics can be adjusted to the target frequency, there are no particular limitations.

[0080] The material of the third unit u3 is described in the same way as the material of the first unit u1.

[0081] exist Figure 2In the resistive layer 10 shown, the first arrangement R1, the second arrangement R2, and the third arrangement R3 are arranged adjacent to each other in the direction indicated by the double arrow P. Thus, with the first arrangement R1, the second arrangement R2, and the third arrangement R3 arranged adjacent to each other in the spacer layer 20, the frequency bands of the electromagnetic waves selectively transmitted by the second conductor pattern 42 and the third conductor pattern 43 overlap, with reference to the frequency value A [GHz] of the peak position of the electromagnetic wave selectively transmitted by the first conductor pattern 41. As a result, the frequency band of the electromagnetic waves transmitted throughout the resistive layer 10, with reference to the frequency value A [GHz] of the peak position, easily extends towards both the high-frequency and low-frequency sides.

[0082] Figure 2 The intervals d1 between the first unit u1 and the second unit u2, d2 between the second unit u2 and the third unit u3, and d3 between the third unit u3 and the first unit u1 shown can be the same or different from each other.

[0083] The interval d1 can be, for example, 0.2mm to 4mm, 0.3mm to 3mm, or 0.5mm to 2mm.

[0084] The interval d2 can be, for example, 0.2mm to 4mm, 0.3mm to 3mm, or 0.5mm to 2mm.

[0085] The interval d3 can be, for example, 0.2mm to 4mm, 0.3mm to 3mm, or 0.5mm to 2mm.

[0086] If the intervals d1, d2, and d3 are within the stated numerical range, the frequency band of the electromagnetic wave transmitted through the resistive layer 10 as a whole can be easily extended further based on the value A [GHz] of the frequency at the peak position.

[0087] In the resistive layer 10, the first unit u1, the second unit u2, and the third unit u3 have the same shape. However, the shapes of the first unit u1, the second unit u2, and the third unit u3 may also be different. That is, in other embodiments of the present invention, the shapes of the first unit u1, the second unit u2, and the third unit u3 may be the same or different.

[0088] The Young's modulus of the resistive layer 10 is preferably 10 GPa or less, more preferably 7 GPa or less, and even more preferably 5 GPa or less. If the Young's modulus of the resistive layer 10 is below the upper limit value, the bending stiffness is reduced and the surface following performance is improved. From the viewpoint of shape maintenance, the lower limit value of the Young's modulus of the resistive layer 10 can be 0.5 GPa or more, 1 GPa or more, or 3 GPa or more.

[0089] The Young's modulus of the resistive layer 10 can be determined according to JIS K7127:1999 "Plastics - Test methods for tensile properties - Part 3: Test conditions for films and sheets".

[0090] The resistive layer 10 can be fabricated, for example, by the following method.

[0091] First, spacer layer 20 is prepared. Next, a first conductor pattern 41, a second conductor pattern 42, and a third conductor pattern 43 are formed in such a way that they are embedded on one side 20a of spacer layer 20.

[0092] When forming each conductor pattern, the value of the frequency at which the absorption of electromagnetic waves absorbed by each conductor pattern reaches its maximum value is defined as [GHz].

[0093] There is no particular restriction on the order in which the various conductive patterns are formed. The conductive patterns can be formed in the same process or in different processes.

[0094] The method for forming each conductor pattern is not particularly limited as long as it can generate the specified frequency. Examples of methods for forming conductor patterns include the following.

[0095] A printing method for printing conductive patterns on one side 20a of spacer layer 20 using conductive paste.

[0096] A development method for developing each conductive pattern on one side 20a of the spacer layer 20.

[0097] A metal thin film is deposited on one side 20a of the spacer layer 20 by sputtering, vacuum evaporation or lamination of metal foil, and the metal thin film is formed on one side 20a of the spacer layer 20 by photolithography.

[0098] A method of placing metal wires on one side 20a of the spacer layer 20.

[0099] A method of forming conductive patterns on a substrate or a release component by the above method, and then stacking the substrate or release component on a surface of a spacer layer before or during melting and cooling, with the conductive patterns side-to-side connected.

[0100] "Interval layer"

[0101] The spacer layer 20 can have a single-layer structure or a multi-layer structure.

[0102] The material of the spacer layer 20 can be appropriately selected according to the application. For example, in the case of automotive exteriors, a material that can follow curved surfaces and has excellent heat resistance is preferred.

[0103] Examples of flexible materials include plastic films, non-woven fabrics, and rubber sheets. Among these, plastic films are preferred from the viewpoint of ease of mixing with fillers.

[0104] The spacer layer 20 may contain filler. There are no particular limitations on the filler as long as it has a high dielectric constant, such as barium titanate, strontium titanate, calcium titanate, titanium oxide, etc.

[0105] The filler content in the spacer layer 20 is preferably 20% by volume or more and 60% by volume or less, more preferably 25% by volume or more and 50% by volume or less, and particularly preferably 30% by volume or more and 45% by volume or less. When the filler content exceeds the upper limit, embrittlement may occur, making the manufacture of the spacer layer 20 difficult. If the filler content is less than the lower limit, the required thickness of the spacer layer 20 becomes too large to obtain the desired electromagnetic wave absorption, and surface following may sometimes be unattainable.

[0106] The relative permittivity of the spacer layer 20 is preferably 5 or higher, more preferably 7 or higher, even more preferably 8 or higher, and particularly preferably 9 or higher. When the relative permittivity of the spacer layer 20 is less than the lower limit value, the thickness of the spacer layer 20 becomes thicker. By making the relative permittivity of the spacer layer 20 5 or higher, the thickness of the spacer layer 20 can be reduced. As a result, the surface following performance of the electromagnetic wave absorbing component 1 can be improved.

[0107] From the perspective of preventing the Young's modulus of spacer layer 20 from becoming too high, the upper limit of the relative permittivity of spacer layer 20 can be below 30, below 25, below 20, or below 15.

[0108] The relative permittivity of spacer layer 20 can be determined by the method described in the embodiments described later.

[0109] The melting point of the spacer layer 20, i.e., the melting point of the material constituting the spacer layer 20, is 150°C or higher, preferably 160°C or higher, and more preferably 170°C or higher. When the melting point of the spacer layer 20 is lower than the aforementioned lower limit, the relative permittivity changes after the heat resistance test, and the performance deteriorates. From the viewpoint of preventing the Young's modulus of the spacer layer 20 from becoming too high, the upper limit of the melting point of the spacer layer 20 can be 400°C or lower, 300°C or lower, 240°C or lower, or 190°C or lower.

[0110] The melting point of spacer layer 20 can be determined by the method described in the examples below.

[0111] The thickness of the spacer layer 20 is preferably 200 μm or more and 450 μm or less, more preferably 240 μm or more and 400 μm or less, and particularly preferably 280 μm or more and 340 μm or less. When the thickness of the spacer layer 20 is above the lower limit, it is easy to obtain a spacer layer 20 with a high relative permittivity. When the thickness of the spacer layer 20 is below the upper limit, the bending stiffness is low and the surface following ability is improved.

[0112] Taking into account the wavelength shortening effect of the spacer layer 20, the thickness of the spacer layer 20 is appropriately varied according to the wavelength of the electromagnetic wave to be absorbed and the relative permittivity of the spacer layer 20.

[0113] Taking into account the wavelength shortening effect of the spacer layer 20, the thickness of the spacer layer 20 preferably satisfies the following equation (1).

[0114] (Thickness of spacer layer 20) = (λ) × (1 / 4) / (ε) 1 / 2 …Formula (1)

[0115] In equation (1) above, λ is the wavelength of the incoming electromagnetic wave, and ε is the relative permittivity of the spacer layer 20. The thickness of the spacer layer 20 can also be adjusted appropriately for absorption characteristics. For example, it can be varied in the range of 0.1 to 3.0 times the thickness of the spacer layer 20 obtained from equation (1).

[0116] When the relationship between the thickness of the spacer layer 20 and the wavelength λ satisfies the above equation (1), the electromagnetic wave absorbing component 1 becomes a so-called λ / 4 structure. As a result, the maximum value of the absorption of electromagnetic waves by the electromagnetic wave absorbing component 1 is further increased.

[0117] The thickness of the spacer layer 20 can be appropriately set within the range of 200 μm or more and 450 μm or less, depending on the wavelength λ of the electromagnetic wave to be absorbed.

[0118] The spacer layer 20 can also be made of a material with a high dielectric constant. When the spacer layer 20 is a layer with a high dielectric constant, the thickness of the spacer layer 20 can be relatively thinned.

[0119] Taking into account the dielectric constant of the spacer layer 20, the spacer layer 20 preferably contains at least one selected from barium titanate, titanium oxide, and strontium titanate.

[0120] The thickness of spacer 20 can be measured using a thickness gauge manufactured by TECLOCK.

[0121] The Young's modulus of the spacer layer 20 is preferably 1000 MPa or less, more preferably 600 MPa or less, and even more preferably 400 MPa or less. If the Young's modulus of the spacer layer 20 is below the aforementioned upper limit value, the surface following performance is improved. From the viewpoint of shape maintenance, the lower limit value of the Young's modulus of the spacer layer 20 can be 50 MPa or more, 100 MPa or more, or 200 MPa or more.

[0122] The Young's modulus of spacer layer 20 can be determined according to JIS K7127:1999 "Plastics - Test methods for tensile properties - Part 3: Test conditions for films and sheets".

[0123] "Reflective layer"

[0124] The reflective layer 30 has two surfaces 30a and 30b. One surface 30a of the reflective layer 30 faces the other surface 20b of the spacer layer 20. Figure 1 In this case, the reflective layer 30 is directly disposed on the other side 20b of the spacer layer 20. Alternatively, the reflective layer 30 may be deposited directly on the other side 20b of the spacer layer 20 by means of vapor deposition or the like.

[0125] The reflective layer 30 is not particularly limited as long as it can reflect electromagnetic waves that fly towards and pass through the electromagnetic wave absorbing component 1. A portion of the electromagnetic waves flying towards the electromagnetic wave absorbing component 1 are reflected or absorbed by the resistive layer 10. On the other hand, electromagnetic waves that are not reflected or absorbed by the resistive layer 10 pass through it. The electromagnetic waves that pass through the resistive layer 10 are reflected towards the resistive layer 10 by the reflective layer 30.

[0126] For example, if the reflective layer 30 is conductive, it can reflect electromagnetic waves that pass through the resistive layer 10. Specifically, the reflective layer 30 can be made of a material formed by bonding aluminum foil, copper foil, or metal plate to a resin film such as polyethylene terephthalate. Alternatively, a mesh formed of a transparent conductive film such as ITO or metal wires can be used instead of metal foil or metal plate.

[0127] In the reflective layer 30, Figure 1 In the case of a single-layer structure as shown, its thickness is not particularly limited. For example, it can be 10nm to 100μm, 40nm to 1μm, or 80nm to 400nm.

[0128] On the other hand, when the reflective layer 30 is made of a material such as a metal foil formed on a resin film, its thickness is preferably 1 μm to 300 μm, more preferably 10 μm to 200 μm, and even more preferably 30 μm to 150 μm. If it is within this range, it is easy to achieve both operability and flexibility of the reflective layer.

[0129] Furthermore, the Young's modulus of the reflective layer 30 is preferably 6 GPa or less, more preferably 5.5 GPa or less, and even more preferably 5 GPa or less. When the Young's modulus of the reflective layer 30 is below the upper limit value, the surface following performance is improved. The lower limit value of the Young's modulus of the reflective layer 30 can be 0.5 GPa or more, 1 GPa or more, or 3 GPa or more.

[0130] The Young's modulus of reflective layer 30 can be determined according to JIS K7127:1999 "Plastics - Test methods for tensile properties - Part 3: Test conditions for films and sheets".

[0131] When the spacer layer 20 is formed on a conductive material such as a metal, the conductive material such as the metal acts as the reflective layer 30, so the reflective layer 30 can be omitted.

[0132] For the purpose of applying the electromagnetic wave absorbing component 1 to the surface of various articles, an adhesive layer can be provided on the other side 30b of the reflective layer 30. When an adhesive layer is provided on the other side 30b of the reflective layer 30, a release film can also be provided on the side of the adhesive layer opposite to the side in contact with surface 30b. The release film is removed when the electromagnetic wave absorbing component 1 is used. By covering the adhesive surface with the release film, the operability during circulation is improved.

[0133] Examples of adhesives that form the adhesive layer include heat-sealing adhesives that bond by heat; adhesives that exhibit adhesiveness when moistened; and pressure-sensitive adhesives (bonding agents) that bond by pressure. Among these, from the viewpoint of simplicity, pressure-sensitive adhesives are preferred.

[0134] Specific examples of adhesives include acrylic adhesives, polyurethane adhesives, rubber adhesives, polyester adhesives, silicone adhesives, and polyvinyl ether adhesives. Preferably, the adhesive is selected from at least one of the group consisting of acrylic adhesives, polyurethane adhesives, and rubber adhesives, and more preferably, an acrylic adhesive.

[0135] Alternatively, the electromagnetic wave absorbing component 1 of this embodiment may also have a protective layer formed on the outermost surface (upper surface) 10a of the resistive layer 10 and one side 20a of the spacer layer 20.

[0136] There are no particular limitations on the protective layer as long as it can protect the resistive layer 10 and the spacer layer 20.

[0137] In the electromagnetic wave absorbing component 1 of this embodiment, the bending stiffness is preferably 240 N·mm. 2 Hereinafter, 100 N·mm is preferred. 2The following is a further preferred value: 60 N·mm 2 The following is particularly preferred: 30 N·mm 2 Below, when the bending stiffness of the electromagnetic wave absorbing component 1 is below the upper limit value, the surface following performance is improved. From the viewpoint of shape maintenance, the lower limit value of the bending stiffness of the electromagnetic wave absorbing component 1 can be 1 N·mm. 2 The above can be 4 N·mm 2 The above can also be expressed as 8 N·mm. 2 above.

[0138] The bending stiffness of the electromagnetic wave absorbing component 1 can be determined by the method described in the embodiments described later.

[0139] Furthermore, from the viewpoint of balancing surface conformability and electromagnetic wave absorption, the total thickness of the electromagnetic wave absorbing component 1 in this embodiment (the total thickness from the outermost surface (upper surface) 10a of the resistive layer 10 and one side 20a of the spacer layer 20 to the other side 30b of the reflective layer 30) is preferably 100 μm to 700 μm, more preferably 200 μm to 600 μm, even more preferably 250 μm to 500 μm, and particularly preferably 280 μm to 340 μm.

[0140] According to the electromagnetic wave absorbing component 1 of this embodiment, the conductive pattern 11 of the resistive layer 10 is embedded on one side 20a of the spacer layer 20, thus exhibiting excellent electromagnetic wave absorption and bending rigidity. Furthermore, since the conductive pattern 11 of the resistive layer 10 is embedded on one side 20a of the spacer layer 20, it exhibits excellent durability against pharmaceuticals. Additionally, because the conductive pattern 11 of the resistive layer 10 is embedded on one side 20a of the spacer layer 20, it is less prone to damage from physical impacts. Moreover, since the electromagnetic wave absorbing component 1 of this embodiment embeds the conductive pattern 11 of the resistive layer 10 on one side 20a of the spacer layer 20 without using adhesives, corrosion of the conductive pattern 11 caused by adhesives will not occur.

[0141] According to the electromagnetic wave absorbing component 1 of this embodiment, if the relative permittivity of the spacer layer 20 is 5 or more, the surface following and the maintenance of electromagnetic wave absorption after the heat resistance test are excellent.

[0142] (Second Implementation)

[0143] Figure 3 The electromagnetic wave absorbing component of one embodiment of the present invention is schematically shown in a cross-sectional view along the thickness of the surface.

[0144] like Figure 3As shown, the electromagnetic wave absorbing component 100 of this embodiment includes a resistive layer 110, a spacer layer 120, a reflective layer 130, and a support substrate 140. The resistive layer 110, spacer layer 120, reflective layer 130, and support substrate 140 are sequentially stacked. An adhesive layer 150 is provided on one side 130a and the other side 130b of the reflective layer 130. The reflective layer 130 is stacked with the spacer layer 120 via the adhesive layer 150. Hereinafter, the adhesive layer 150 provided on one side 130a of the reflective layer 130 is sometimes referred to as the first adhesive layer 151, and the adhesive layer 150 provided on the other side 130b of the reflective layer 130 is sometimes referred to as the second adhesive layer 152.

[0145] The conductive pattern 112 of the resistive layer 110 is embedded in the spacer layer 120 on the opposite side (one side (surface)) 120a of the surface (other side (back side)) 120b opposite to the reflective layer 130. Furthermore, the outermost surface (upper surface) 112a of the conductive pattern 112 is disposed on the same surface as one side 120a of the spacer layer 120. The spacer layer 120 is disposed between the resistive layer 110 and the reflective layer 130. That is, the resistive layer 110 and the reflective layer 130 are stacked with the spacer layer 120 in between.

[0146] "Resistive layer"

[0147] The resistive layer 110 includes a substrate 111 and a conductive pattern 112 formed on one side 111a of the substrate 111.

[0148] Conductor pattern 112 has the same structure as conductor pattern 11 described above.

[0149] The substrate 111 is flat, and there are no particular limitations as long as the conductive pattern 112 can be formed on one side 111a. The substrate 111 can be a single-layer structure or a multi-layer structure.

[0150] The thickness of the substrate 111 can be, for example, 5μm to 500μm, 15μm to 200μm, or 25μm to 100μm.

[0151] The material of the substrate 111 can be appropriately selected according to the application of the electromagnetic wave absorbing component 100.

[0152] For example, to achieve transparency of the electromagnetic wave absorbing component 100, the substrate 111 can be made of a transparent material. Alternatively, to achieve conformability to the curved surface of the electromagnetic wave absorbing component 100, the substrate 111 can be made of a flexible material. To improve the transparency and three-dimensional formability of the electromagnetic wave absorbing component 100, the surface of the substrate 111 can be made smooth.

[0153] For example, the substrate 111 can be made of resin. The resin can be a thermoplastic resin or a thermosetting resin. However, considering the three-dimensional formability of the electromagnetic wave absorbing component 100, the substrate 111 preferably comprises a thermoplastic resin.

[0154] Examples of thermoplastic resins include polyolefin resins, polyester resins, polyester-polyether resins, polyacrylic resins, polystyrene resins, polyimide resins, polyimide amide resins, polyamide resins, polyurethane resins, polycarbonate resins, polyarylate resins, melamine resins, epoxy resins, polyurethane resins, silicone resins, and fluoropolymers.

[0155] Specific examples of polyolefin resins include polypropylene and polyethylene. Specific examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.

[0156] The substrate 111 may contain any components without impairing the effects of the present invention. Examples of such components include inorganic fillers, colorants, curing agents, anti-aging agents, light stabilizers, flame retardants, conductive agents, antistatic agents, plasticizers, etc.

[0157] To further improve the electromagnetic wave absorption performance of the electromagnetic wave absorbing component 100, the thickness, dielectric constant, conductivity, and permeability of the substrate 111 can be appropriately set.

[0158] "Interval layer"

[0159] Spacer layer 120 has the same structure as spacer layer 20 described above.

[0160] "Reflective layer"

[0161] The reflective layer 130 has the same structure as the reflective layer 30 described above.

[0162] "Support substrate"

[0163] The support substrate 140 is laminated on the other side 130b of the reflective layer 130 via a second adhesive layer 152. One side 140a of the support substrate 140 is opposite to the other side 130b of the reflective layer 130.

[0164] "Adhesive layers (first adhesive layer, second adhesive layer)"

[0165] Examples of adhesives constituting the first adhesive layer 151 and the second adhesive layer 152 include heat-sealing adhesives that bond by heat; adhesives that exhibit adhesiveness when wetted; and pressure-sensitive adhesives that bond by pressure. Among these, pressure-sensitive adhesives are preferred from the viewpoint of simplicity.

[0166] Specific examples of adhesives include acrylic adhesives, polyurethane adhesives, rubber adhesives, polyester adhesives, silicone adhesives, and polyvinyl ether adhesives. Preferably, the adhesive is selected from at least one of the group consisting of acrylic adhesives, polyurethane adhesives, and rubber adhesives, and more preferably, an acrylic adhesive.

[0167] The thickness of the first adhesive layer 151 and the second adhesive layer 152 is not particularly limited. For example, it can be 1μm to 1000μm, 5μm to 500μm, or 10μm to 40μm.

[0168] In the electromagnetic wave absorbing component 100 of this embodiment, the bending stiffness is preferably 240 N·mm. 2 Below, 120 N·mm is preferred. 2 The following is a further preferred value: 60 N·mm 2 Below. If the bending stiffness of the electromagnetic wave absorbing component 100 is below the upper limit value, the surface following performance is improved. From the viewpoint of shape maintenance, the lower limit value of the bending stiffness of the electromagnetic wave absorbing component 100 can be 5 N·mm. 2 The above can be 10 N·mm 2 The above can also be 20 N·mm. 2 above.

[0169] The bending stiffness of the electromagnetic wave absorbing component 100 can be determined by the method described in the embodiments described later.

[0170] Furthermore, from the viewpoint of balancing surface conformability and electromagnetic wave absorption, the total thickness of the electromagnetic wave absorbing component 100 in this embodiment (the total thickness from the outermost surface of the resistive layer, i.e., one surface (surface) 110a of the resistive layer 110 to the surface (other surface) 140b on the side of the mounting surface of the support substrate 140) is preferably 150 μm to 1000 μm, more preferably 200 μm to 800 μm, even more preferably 250 μm to 650 μm, and particularly preferably 350 μm to 430 μm.

[0171] According to the electromagnetic wave absorbing component 100 of this embodiment, the conductive pattern 112 of the resistive layer 110 is embedded on one side 120a of the spacer layer 120, thus exhibiting excellent electromagnetic wave absorption and bending rigidity. Furthermore, since the conductive pattern 112 of the resistive layer 110 is embedded on one side 120a of the spacer layer 120 and is thus protected by the substrate 111, it exhibits excellent durability against pharmaceuticals. Additionally, for the same reason, the conductive pattern 112 is less prone to damage from physical impacts.

[0172] Example

[0173] The present invention will now be described in more detail by way of examples and comparative examples, but the present invention is not limited to the following examples.

[0174] [Example 1]

[0175] Fabrication of Electromagnetic Wave Absorbing Components

[0176] A copper thin film is formed by printing a pattern of washable ink on a substrate made of a 50μm thick PET film (trade name: PET50A 4160, manufactured by Toyobo Co., Ltd.) and then depositing a copper film with a thickness of 100nm.

[0177] Then, the ink is washed with water to remove the copper film on the water-washed ink, thereby patterning it as shown. Figure 2 The conductive pattern shown is used to obtain a resistive layer.

[0178] Next, the polyester-polyether copolymer (trade name: P-55B, manufactured by Toyobo Co., Ltd.) as resin and barium titanate (trade name: BT-UP2, manufactured by Nippon Chemical Co., Ltd.) as filler were mixed at 200°C and 40 rpm for 5 minutes using LABOPLASTOMILL (model name: 4C150, manufactured by Toyo Seiki Co., Ltd.) to prepare a mixed material with a barium titanate content of 40% by volume.

[0179] The above-mentioned mixed material is placed on the conductive pattern forming surface of the resistive layer and pressed at 200°C for 3 minutes using a hydraulic hot press (model name: SA-32, manufactured by TESTER SANGYO Co., Ltd.) to obtain a laminate of resistive layer and spacer layer (thickness 300μm) with a total thickness of 350μm.

[0180] As the adhesive layer material, an acrylic copolymer with a weight average molecular weight of 800,000 was prepared, consisting of 70% by mass of 2-ethylhexyl acrylate, 29% by mass of n-butyl acrylate, 0.5% by mass of acrylic acid, and 0.5% by mass of 2-hydroxyethyl acrylate. One part by mass of isocyanate-based crosslinking agent and eight parts by mass of ultraviolet absorber (trade name: Tinuvin 477, manufactured by BASF Japan Co., Ltd.) were added to 100 parts by mass of this acrylic copolymer (converted to solids content), and the mixture was diluted with ethyl acetate to prepare an acrylic adhesive solution.

[0181] Next, the acrylic adhesive solution was applied to the release film, dried at 90°C for 1 minute, and then cured at room temperature for 1 week to obtain an adhesive layer with a thickness of 20 μm.

[0182] Next, as a reflective layer, a 50 μm thick aluminum vapor-deposited PET film (manufactured by Toray Film Processing Co., Ltd., trade name: Metallme TS; aluminum layer thickness 100 nm) is prepared and laminated with the adhesive layer covering the aluminum vapor-deposited side of the film, removing the release film present in the adhesive layer. Then, the exposed side of the adhesive layer is attached to the exposed side of the spacer layer of the above-described laminate to obtain an electromagnetic wave absorbing component.

[0183] [Example 2]

[0184] A copper thin film is formed by printing washable ink onto a substrate consisting of a 50μm thick PET film without an easy-to-adhere layer, and then depositing a copper film with a thickness of 100nm.

[0185] Then, the copper film on the ink is removed by washing with water, thereby patterning it as shown. Figure 2 The conductive pattern shown is used to obtain a resistive layer.

[0186] Next, the polyester-polyether copolymer (trade name: P-55B, manufactured by Toyobo Co., Ltd.) as resin and barium titanate (trade name: BT-UP2, manufactured by Nippon Chemical Co., Ltd.) as filler were mixed at 200°C and 40 rpm for 5 minutes using LABOPLASTOMILL (model name: 4C150, manufactured by Toyo Seiki Co., Ltd.) to prepare a mixed material with a barium titanate content of 40% by volume.

[0187] The above-mentioned mixed material was placed on the conductive pattern forming surface of the resistive layer, and a hydraulic hot press (model name: SA-32, manufactured by TESTER SANGYO Co., Ltd.) was used. The lower stage was set to 180°C and the upper stage was set to 220°C. The press was pressed for 3 minutes to obtain a laminate of resistive layer and spacer layer (thickness 300μm) with a total thickness of 350μm.

[0188] Next, a copper layer with a thickness of 100 nm was deposited on the side opposite to the resistive layer of the above-prepared laminate using a sputtering apparatus.

[0189] Finally, the PET film, which serves as the substrate of the resistive layer, is peeled off to obtain the electromagnetic wave absorbing component.

[0190] [Comparative Example]

[0191] Fabrication of Electromagnetic Wave Absorbing Components

[0192] A resistive layer was obtained in the same manner as in Example 1.

[0193] Next, the polyester-polyether copolymer (trade name: P-55B, manufactured by Toyobo Co., Ltd.) as resin and barium titanate (trade name: BT-UP2, manufactured by Nippon Chemical Co., Ltd.) as filler were mixed at 200°C and 40 rpm for 5 minutes using LABOPLASTOMILL (model name: 4C150, manufactured by Toyo Seiki Co., Ltd.) to prepare a mixed material with a barium titanate content of 40% by volume.

[0194] The above-mentioned mixed material was pressed at 200°C for 3 minutes using a hydraulic hot press (model name: SA-302, manufactured by TESTER SANGYO Co., Ltd.) to obtain a spacer layer with a thickness of 300μm.

[0195] As the adhesive layer material, an acrylic copolymer with a weight average molecular weight of 800,000 was prepared, consisting of 70% by mass of 2-ethylhexyl acrylate, 29% by mass of n-butyl acrylate, 0.5% by mass of acrylic acid, and 0.5% by mass of 2-hydroxyethyl acrylate. One part by mass of isocyanate-based crosslinking agent and eight parts by mass of ultraviolet absorber (trade name: Tinuvin 477, manufactured by BASF Japan Co., Ltd.) were added to 100 parts by mass of this acrylic copolymer (converted to solids content), and the mixture was diluted with ethyl acetate to prepare an acrylic adhesive solution.

[0196] Next, the acrylic adhesive solution was applied to the release film, dried at 90°C for 1 minute, and then cured at room temperature for 1 week to obtain an adhesive layer with a thickness of 20 μm.

[0197] Next, the adhesive layer is stacked on one side of the spacer layer, the release film of the adhesive layer is peeled off, and the resistive layer is stacked in such a way that the conductive pattern side contacts the exposed surface of the adhesive layer.

[0198] Next, as a reflective layer, a 50 μm thick aluminum vapor-deposited PET film (manufactured by Toray Film Processing Co., Ltd., trade name: Metallme TS; aluminum layer thickness 100 nm) is prepared and laminated by covering the aluminum vapor-deposited surface of the film with an adhesive layer. The release film is then peeled off and attached to the exposed side of the aforementioned spacer layer. This yields an electromagnetic wave absorbing component.

[0199] [evaluate]

[0200] The electromagnetic wave absorbing components of Examples 1, 2, and the comparative examples were evaluated as follows. The results are shown in Table 1.

[0201] "Evaluation of surface following performance"

[0202] An adhesive layer prepared in Example 1 was attached to the surface of the reflective layer side of the electromagnetic wave absorbing component obtained in the Examples and Comparative Examples to prepare a measurement sample.

[0203] For this test sample, the release film was peeled off and pasted onto curved surfaces of different diameters to evaluate the surface following performance of the electromagnetic wave absorbing component.

[0204] The smallest diameter (mm) of the curved surface that can attach the electromagnetic wave absorbing component to the curved surface without wrinkles, lifting at the ends, or other aesthetic defects.

[0205] Evaluation of bending stiffness

[0206] use Figure 4 The bending stiffness of the electromagnetic wave absorbing component is calculated using the following formula (11).

[0207] Will Figure 4 The position of the centroid of the electromagnetic wave absorbing component in the middle is set as y. c The width of the electromagnetic wave absorbing component is set to W. Furthermore, the thicknesses of the resistive layer, the spacer layer, and the reflective layer are set to t1, t2, and t3, respectively, and the heights to the center of each layer are set to y1, y2, and y3, respectively.

[0208] The areas (A1, A2, A3) of the resistive layer, the spacer layer and the reflective layer, as well as the overall area A and y1, y2, y3, are calculated using the following formulas (11) to (17).

[0209] A1=W×t1(11)

[0210] A2=W×t2(12)

[0211] A3 = W × t3 (13)

[0212] A = A1 + A2 + A3 (14)

[0213] y1=t1 / 2(15)

[0214] y2=t1+t2 / 2(16)

[0215] y3=t1+t2+t3 / 2(17)

[0216] Using the values ​​obtained from equations (11) to (17), the center y of the electromagnetic wave absorbing component is calculated using the following equation (18). c .

[0217] y c =(A1y1+A2y2+A3y3) / A(18)

[0218] Here, the moments of inertia I1, I2, I3 and I4 related to the centroid of each layer are calculated using the following equations (20) to (25). c1 I c2 I c3 .

[0219] I1 = (W × t1) 3 ) / 12 (20)

[0220] I2 = (W × t2) 3 ) / 12 (21)

[0221] I3 = (W × t3) 3 ) / 12 (22)

[0222] I c1 =I1+A1×(y c -y1) 2 (twenty three)

[0223] I c2 =I² + A² × (y c -y2) 2 (twenty four)

[0224] I c3 =I3+A3×(y c -y3) 2 (25)

[0225] The moment of inertia I of the electromagnetic wave absorbing component is calculated by the following formula (26), and the bending stiffness of the electromagnetic wave absorbing component is determined by the following formula (27).

[0226] I=I c1 +I c2 +I c3 (26)

[0227] Bending stiffness (N·mm) 2 ) = E (N / mm 2 )×I (mm) 4 (27)

[0228] Evaluation of reflection attenuation

[0229] The heat resistance of the electromagnetic wave absorbing component was tested using a high-temperature humidifier (model name: PHH-102) manufactured by ESPEC Corporation. The temperature of the humidifier was set to 120°C, and the electromagnetic wave absorbing component was immersed in the humidifier for 240 hours. The reflection attenuation of the electromagnetic wave absorbing component after it was removed from the humidifier was measured, and the changes before and after the test were evaluated.

[0230] The reflection attenuation was determined by the free space method.

[0231] "Determination of Young's Modulus"

[0232] Tensile tests were conducted on the resistive layer obtained in Example 1, the spacer layer obtained in the comparative example, and the aluminum vapor-deposited PET film used as a reflective layer in Example 1 under the following conditions. Based on the measured strain and stress, the stress change relative to strain was graphically plotted. Young's modulus was determined based on the initial slope of the stress change relative to the strain change. The results are shown in Table 1.

[0233] • Apparatus: Shimadzu AG-X plus 10kN tensile testing machine

[0234] • Test sample size: Measurement area length 50mm × width 15mm • Tensile test speed: 200mm / min

[0235] [Table 1]

[0236]

[0237] As shown in Table 1, the electromagnetic wave absorption and bending rigidity of the electromagnetic wave absorbing components in Examples 1 and 2 are excellent after thermal testing.

[0238] On the other hand, it can be seen that the electromagnetic wave absorption properties of the electromagnetic wave absorbing component of the comparative example are poorly maintained after the thermal test.

[0239] [Potential for Industrial Applications]

[0240] The electromagnetic wave absorbing component of the present invention can be used as an electromagnetic wave absorbing component in transportation equipment such as automobiles.

[0241] Explanation of reference numerals in the attached figures

[0242] 1, 100: Electromagnetic wave absorbing component

[0243] 10, 110: Resistive layer

[0244] 11, 112: Conductor Patterns

[0245] 20, 120: Spacing layer

[0246] 30, 130: Reflective layer

[0247] 41: Pattern of the first conductor

[0248] 42: Second conductor pattern

[0249] 43: Third conductor pattern

[0250] 111: Substrate

[0251] 140: Support substrate

[0252] 150: Adhesive layer

Claims

1. An electromagnetic wave absorbing component, characterized in that, It has a resistive layer, a spacer layer and a reflective layer. The resistive layer, the spacer layer, and the reflective layer are stacked sequentially. The resistive layer has a conductive pattern. The conductive pattern is embedded in the spacer layer on the opposite side of the surface opposite to the reflective layer.

2. The electromagnetic wave absorbing component according to claim 1, characterized in that, The relative permittivity of the spacer layer is 5 or higher.

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