Radio wave transmission member, method for manufacturing radio wave transmission member, automobile

Abstract

A radio-wave-transmitting member provided with an outer layer, an intermediate layer, and an inner layer in this order, the radio-wave-transmitting member having a region in which the thicknesses X of the outer layer and the inner layer in the radio-wave-transmitting direction respectively satisfy (1) and (2). Formula (1) Z-0.3 mm < = X < = Z + 0.3 mm Formula (2) Z = [lambda] / [square root of] [epsilon] r * 0.5 * Y, in the formula, [lambda] is the wavelength of the radio wave in vacuum, [epsilon] r is the relative dielectric constant of each layer at the frequency of the radio wave, and Y is an integer greater than or equal to 1.

Description

Technical Field

[0001] The present disclosure relates to a radio wave transmitting member, a method for manufacturing the radio wave transmitting member, an automobile component, a sign, and an object detection structure. Background Art

[0002] In recent years, safety devices have been significantly improved in automobiles. For example, automatic collision avoidance systems have become common.

[0003] The automatic collision avoidance system automatically applies the brakes using image data from an onboard camera and information on the relative distance to an object obtained by a transceiver of radio waves such as millimeter waves.

[0004] The radio wave transceiver constituting the automatic collision avoidance system is preferably arranged in the front center of the car. The car logo is generally arranged in the front center of the car. Therefore, it is desirable to arrange the radio wave transceiver behind the car logo.

[0005] Automobile logos generally have a structure in which a metal layer for expressing metallic luster is formed on a substrate such as resin. For example, Patent Documents 1 and 2 disclose a structure having a metal layer formed by a silver mirror reaction on a substrate as a logo having metallic luster and capable of transmitting radio waves.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2003-019765

[0007] Patent Document 2: Japanese Patent Application Publication No. 2019-177311 Summary of the invention

[0008] Problems to be solved by the invention

[0009] From the viewpoint of ensuring sufficient performance of the automatic collision avoidance system, it is desirable to suppress the attenuation of radio waves transmitted through the sign as much as possible.

[0010] In view of the above circumstances, an object of the present disclosure is to provide a radio wave transmitting member capable of suppressing transmission attenuation of radio waves, a method for manufacturing the radio wave transmitting member, an automobile component, a sign, and an object detection structure.

[0011] Methods for solving problems

[0012] The specific method for achieving the above-mentioned subject is as follows.

[0013] <1> A radio wave transmitting member comprises an outer layer, an intermediate layer and an inner layer in this order.

[0014] The radio wave transmitting member has a region in which the thicknesses X of the outer layer and the inner layer in the radio wave transmitting direction satisfy the following equations (1) and (2), respectively.

[0015] Formula (1) Z-0.3mm≤X≤Z+0.3mm

[0016] Formula (2) Z=λ÷√ε r ×0.5×Y

[0017] In the formula, λ is the wavelength of the above radio wave in vacuum, ε r is the relative dielectric constant of each layer at the frequency of the above-mentioned radio wave, and Y is an integer greater than or equal to 1.

[0018] <2> according to <1> In the radio wave transmitting member, in the above region, the thickness X of the intermediate layer satisfies the above formula (1) and formula (2).

[0019] <3> according to <1> or <2> In the radio wave transmitting component, the intermediate layer is an air layer.

[0020] <4> according to <1> ~ <3> In the radio wave transmitting member described in any one of the above, the outer layer and the inner layer each contain a resin.

[0021] <5> according to <1> ~ <4> The radio wave transmitting member described in any one of the above aspects further includes a metal layer capable of transmitting the radio wave.

[0022] <6> according to <5> In the radio wave transmitting component, the metal layer is arranged between the outer layer and the middle layer or between the inner layer and the middle layer.

[0023] <7> according to <1> ~ <6> The radio wave transmitting member described in any one of the above is used for transmitting radio waves having a frequency of 20 GHz to 300 GHz.

[0024] <8> A method for manufacturing a radio wave transmitting component, wherein the radio wave transmitting component comprises an outer layer, an intermediate layer and an inner layer in sequence, and the manufacturing method comprises: determining the thickness of the outer layer and the inner layer so that the thickness X of the outer layer and the inner layer in the radio wave transmitting direction satisfies the following equations (1) and (2) respectively.

[0025] Formula (1) Z-0.3mm≤X≤Z+0.3mm

[0026] Formula (2) Z=λ÷√ε r ×0.5×Y

[0027] In the formula, λ is the wavelength of the above radio wave in vacuum, ε r is the relative dielectric constant of each layer at the frequency of the above-mentioned radio wave, and Y is an integer greater than or equal to 1.

[0028] <9> An automobile component comprising <1> ~ <7> The radio wave transmitting member as described above.

[0029] <10> A sign containing <1> ~ <7> The radio wave transmitting member as described above.

[0030] <11> An object detection structure having <1> ~ <7> The radio wave transmitting member described in any one of the above and the device for irradiating the radio wave to the radio wave transmitting member.

[0031] Effects of the Invention

[0032] According to the present disclosure, there are provided a radio wave transmitting member capable of suppressing transmission attenuation of radio waves, a method for manufacturing the radio wave transmitting member, an automobile component, a sign, and an object detection structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic cross-sectional view showing an example of the structure of a radio wave transmitting member.

[0034] Figure 2 This is a schematic diagram showing an example of an automobile component including a radio wave transmitting member.

[0035] Figure 3 This is a schematic diagram showing an example of an automobile component including a radio wave transmitting member.

[0036] Figure 4 This is a schematic diagram showing an example of an automobile component including a radio wave transmitting member. DETAILED DESCRIPTION

[0037] Hereinafter, the method for implementing the present disclosure is described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, except for the cases specifically indicated, the constituent elements (including element steps, etc.) are not necessary. Numerical values ​​and their ranges are also the same and do not limit the present disclosure.

[0038] In the present disclosure, in a numerical range expressed using "to", the numerical values ​​described before and after "to" are included as the minimum value and the maximum value, respectively.

[0039] In the numerical range recorded in stages in the present disclosure, the upper limit or lower limit recorded in a numerical range can also be replaced by the upper limit or lower limit of the numerical range recorded in other stages. In addition, in the numerical range recorded in the present disclosure, the upper limit or lower limit of the numerical range can also be replaced by the value shown in the embodiment.

[0040] In the present disclosure, each component may contain a plurality of substances corresponding to each component. When a plurality of substances corresponding to each component are present in the composition, unless otherwise specified, the content or content of each component refers to the total content or content of the plurality of substances present in the composition.

[0041] In the present disclosure, particles corresponding to each component may include multiple types of particles.

[0042] In the present disclosure, the term "layer" or "film" includes not only the case where a region where the layer or film exists is observed but also the case where the layer or film is formed on only a part of the region.

[0043] In the present disclosure, “(meth)acrylic acid” is a word used as a concept including both acrylic acid and methacrylic acid.

[0044] <Radio wave transmitting member>

[0045] The radio wave transmitting member disclosed in the present invention comprises an outer layer, an intermediate layer and an inner layer in this order.

[0046] The radio wave transmitting member has a region in which the thicknesses X of the outer layer and the inner layer in the radio wave transmitting direction satisfy the following equations (1) and (2), respectively.

[0047] Formula (1) Z-0.3mm≤X≤Z+0.3mm

[0048] Formula (2) Z=λ÷√ε r ×0.5×Y

[0049] In the formula, λ is the wavelength of the above radio wave in vacuum, ε r is the relative dielectric constant of each layer at the frequency of the above-mentioned radio wave, and Y is an integer greater than or equal to 1.

[0050] The radio wave transmitting component disclosed in the present invention has a structure in which an outer layer, an intermediate layer and an inner layer are stacked in sequence for reasons of ensuring strength and molding process. Therefore, if the materials of the layers are different, radio waves will be reflected at the boundaries of the layers, and the attenuation of radio waves passing through the radio wave transmitting component may increase.

[0051] In the radio wave transmitting member of the present disclosure, the attenuation of radio waves transmitted through the radio wave transmitting member is effectively suppressed by designing the outer layer and the inner layer to have regions where the thickness X satisfies equations (1) and (2), respectively.

[0052] Furthermore, by designing the thickness X of the outer layer and the inner layer to satisfy the formula (1) and the formula (2), even if the thickness X of the intermediate layer is not designed to satisfy the formula (1) and the formula (2), the attenuation of the radio wave can be effectively suppressed. Therefore, for example, by making the thickness of the intermediate layer thinner, the transmittance of the radio wave can be further improved.

[0053] Figure 1 This is a schematic cross-sectional view showing an example of the structure of a radio wave transmitting member.

[0054] Figure 1The radio wave transmitting member 10 shown includes an outer layer 1, an intermediate layer 2, and an inner layer 3 in this order, and transmits radio waves irradiated from a device (not shown) for irradiating radio waves, and transmits radio waves reflected from an object.

[0055] The outer layer 1 is disposed on the opposite side from the device that irradiates the radio waves to the radio wave transmitting member 10. The inner layer 3 is disposed on the side opposite to the device that irradiates the radio waves to the radio wave transmitting member.

[0056] The frequency of the radio wave transmitted through the radio wave transmitting member is not particularly limited. For example, the wavelength in a vacuum may be in the range of 20 GHz to 300 GHz (so-called millimeter wave).

[0057] When the radio wave transmitting member is used in an automatic collision avoidance system of an automobile, radio waves generally used in the automatic collision avoidance system include radio waves with a frequency of 24 GHz to 79 GHz, such as radio waves with a frequency of 24 GHz, 77 GHz, and 79 GHz. The wavelengths of these radio waves in a vacuum are 12.49135 mm (24 GHz), 3.893409 mm (77 GHz), and 3.794841 mm (79 GHz).

[0058] In the formula, Y is not particularly limited as long as it is an integer greater than or equal to 1, and can be set according to the desired shape and strength of the radio wave transmitting member.

[0059] From the viewpoint of more effectively suppressing the attenuation of radio waves passing through the radio wave transmitting component, the smaller the difference between the thickness X and Z of the outer layer and the inner layer in the radio wave transmitting direction, the better. That is, the thickness X of the outer layer and the inner layer in the radio wave transmitting direction preferably satisfies the following formula (1'), and more preferably satisfies the following formula (1").

[0060] Formula (1'): Z-0.2mm≤X≤Z+0.2mm

[0061] Formula (1”): Z-0.1mm≤X2≤Z+0.1mm

[0062] In the region where the thickness X of the outer layer and the inner layer respectively satisfy the equation (1) and the equation (2), the thickness X of the intermediate layer may or may not satisfy the equation (1) and the equation (2).

[0063] When the frequency of the radio wave transmitted through the radio wave transmitting member is 77 GHz and the wavelength in vacuum is 3.893409 mm, the value of Z (Y = 1 to 13, unit: mm) when the relative dielectric constant at 77 GHz is 2.574 and the value of Z (Y = 1 to 13, unit: mm) when the relative dielectric constant at 77 GHz is 1.0 (i.e., air) are shown in Table 1. The values ​​in the table are values ​​rounded off to the third decimal place.

[0064] [Table 1]

[0065]

[0066] From the viewpoint of obtaining a sufficient radio wave attenuation suppression effect, the ratio of the area of ​​the regions where the thickness X of the outer layer and the inner layer respectively satisfies the equations (1) and (2) to the overall area of ​​the radio wave transmitting component is preferably greater than or equal to 50%, more preferably greater than or equal to 60%, and further preferably greater than or equal to 70%.

[0067] The above ratio is a value based on the area of ​​the radio wave transmitting member when the radio wave transmitting member is viewed from the outer layer side.

[0068] From the viewpoint of the balance between strength and radio wave transmittance, the outer layer and the inner layer are each preferably a layer containing a resin.

[0069] From the viewpoint of radio wave transmittance, the intermediate layer is preferably an air layer or a layer containing a resin, and more preferably an air layer.

[0070] When the outer layer, the inner layer or the intermediate layer is a layer containing a resin, the relative dielectric constant of the resin may be independently 2.0 to 3.3, 2.3 to 2.9, or 2.5 to 2.8.

[0071] Examples of the resin that may be contained in the outer layer, the intermediate layer, or the inner layer include thermosetting resins, thermoplastic resins, and synthetic rubbers.

[0072] Examples of the thermoplastic resin include polyethylene (PE), polypropylene (PP), polycarbonate (PC), polystyrene, polyvinyl chloride, vinyl polymers, polyesters, polyamides, acrylonitrile-butadiene-styrene copolymer resins (ABS resins), (meth)acrylic resins, acrylonitrile-ethylene-propylene-diene-styrene copolymer resins (AES resins), and thermoplastic elastomers.

[0073] Examples of the thermosetting resin include silicone resins, polyurethane resins, melamine resins, epoxy resins, phenolic resins, and urea resins.

[0074] Examples of the synthetic rubber include ethylene-propylene-diene rubber (EPDM), nitrile rubber (NBR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), silicone rubber, and polyurethane rubber.

[0075] Among the above resins, PC, PP, ABS resin, (meth)acrylic resin and AES resin are preferred, and PC, PP and ABS resin are more preferred.

[0076] When the outer layer, the middle layer or the inner layer is a layer containing a resin, the outer layer, the middle layer or the inner layer may contain only the resin, or may contain the resin and a component other than the resin.

[0077] As components other than the resin, inorganic particles, a colorant, an antistatic agent, light diffusion particles described later, and the like are mentioned.

[0078] When the outer layer, the middle layer or the inner layer contains a resin and a component other than the resin, the content of the resin contained in the outer layer, the middle layer or the inner layer is preferably greater than or equal to 60% by mass, more preferably greater than or equal to 70% by mass, further preferably greater than or equal to 80% by mass, and particularly preferably greater than or equal to 90% by mass. The upper limit of the content of the resin is not particularly limited as long as it is less than 100% by mass.

[0079] The outer layer, the middle layer or the inner layer may also have a light diffusion function.

[0080] If the outer layer, the middle layer or the inner layer has a light diffusion function, the radio wave transmitting member can be irradiated with light to make the radio wave transmitting member emit light. Thus, various expressions using light can be realized.

[0081] Examples of a method for imparting a light diffusion function to the outer layer, the intermediate layer, or the inner layer include a method of incorporating light diffusion particles and a method of forming irregularities on the surface.

[0082] The outer layer, the middle layer or the inner layer having a light diffusion function may have the light diffusion function entirely or partially.

[0083] Among the above methods, the method containing light diffusion particles is preferred from the viewpoint of productivity.

[0084] Examples of the light-diffusing particles include acrylic resin particles, silicone resin particles, titanium oxide particles, silicon dioxide particles, zirconium oxide particles, zinc oxide particles, and aluminum oxide particles.

[0085] The light diffusion particles may be used alone or in combination of two or more.

[0086] When the outer layer, the middle layer or the inner layer contains light diffusion particles, the content of the light diffusion particles is not particularly limited. For example, the content of the light diffusion particles may be 0.3% to 10% by mass of the entire outer layer, the middle layer or the inner layer.

[0087] The thickness of each of the outer layer, the intermediate layer and the inner layer is not particularly limited as long as the thickness of the outer layer and the inner layer respectively satisfy the conditions of formula (1) and formula (2), and can be set according to the purpose of the radio wave transmitting member, etc.

[0088] The thickness of the outer layer may be 1.0 mm to 15.0 mm, 1.5 mm to 12.0 mm, or 2.0 mm to 10.0 mm.

[0089] The thickness of the intermediate layer may be 0.1 mm to 6.0 mm, 0.3 mm to 4.0 mm, or 0.5 mm to 2.0 mm.

[0090] The thickness of the inner layer may be 1.0 mm to 15.0 mm, 1.5 mm to 12.0 mm, or 2.0 mm to 10.0 mm.

[0091] The above thickness is the thickness in the region where the thickness X of the outer layer and the inner layer respectively satisfies the condition of the formula (1).

[0092] In the present disclosure, the thickness of the radio wave transmitting member and each layer constituting the radio wave transmitting member can be measured by a known method, for example, by observing the cross section of the radio wave transmitting member or by using a microtome or the like.

[0093] The radio wave transmitting member may include a metal layer that can transmit radio waves. By providing the radio wave transmitting member with the metal layer that can transmit radio waves, a metallic luster can be imparted to the radio wave transmitting member.

[0094] When the radio wave transmitting member includes a metal layer that can transmit radio waves, the metal layer that can transmit radio waves is preferably provided between the outer layer and the middle layer or between the inner layer and the middle layer.

[0095] As the metal layer capable of transmitting radio waves, a film containing metal particles can be mentioned. When the metal particles are in a state of containing metal particles, radio waves can transmit through gaps between the metal particles.

[0096] The metal layer may be a metal layer containing silver particles. The metal layer containing silver particles may be formed by, for example, a silver mirror reaction.

[0097] As a method for forming a metal layer by a silver mirror reaction, there is a method of bringing an aqueous ammoniacal silver nitrate solution into contact with an aqueous reducing agent solution on a substrate, thereby causing a redox reaction to precipitate silver particles, thereby forming a metal layer containing silver particles on the substrate.

[0098] When a metal layer is provided between the outer layer and the intermediate layer by the above method, the member forming the outer layer can be used as the base material, and when a metal layer is provided between the inner layer and the intermediate layer, the member forming the inner layer can be used as the base material.

[0099] From the viewpoint of radio wave transmittance, the thickness of the metal layer is more preferably 1000 nm or less, more preferably 500 nm or less, and further preferably 100 nm or less.

[0100] From the viewpoint of imparting sufficient metallic luster to the radio wave transmitting member, the thickness of the metal layer is preferably 10 nm or more.

[0101] When a metal layer is provided between the outer layer and the intermediate layer or between the inner layer and the intermediate layer, a primer layer may be provided between the outer layer or the inner layer and the metal layer in order to improve the adhesion between the outer layer or the inner layer and the metal layer.

[0102] Alternatively, in order to protect the surface of the metal layer, a protective layer may be provided on the metal layer.

[0103] Examples of the primer layer or the protective layer include layers containing resins, and examples of the resins include fluororesins, polyester resins, epoxy resins, melamine resins, silicone resins, acrylic silicone resins, acrylic urethane resins, and the like.

[0104] The thickness of the primer layer or the protective layer is preferably 1 μm to 50 μm. If the thickness of the primer layer or the protective layer is 1 μm to 50 μm, the radio wave attenuation suppression effect produced by controlling the thickness of the outer layer, the intermediate layer, and the inner layer can be fully obtained.

[0105] The type of radio waves transmitted through the radio wave transmitting member is not particularly limited, and may be, for example, millimeter waves. In the present disclosure, "millimeter waves" refer to radio waves with a frequency of 20 GHz to 300 GHz. The radio wave transmitting member of the present disclosure is particularly useful for reducing the transmission attenuation of millimeter waves.

[0106] <Method for manufacturing radio wave transmitting member>

[0107] The manufacturing method of the radio wave transmitting component disclosed in the present invention is a manufacturing method of the radio wave transmitting component which has an outer layer, an intermediate layer and an inner layer in sequence, comprising: determining the thickness of the outer layer and the inner layer so that the thickness X of the outer layer and the inner layer in the radio wave transmitting direction satisfies the following formula (1) and formula (2) respectively.

[0108] Formula (1): Z-0.3mm≤X≤Z+0.3mm

[0109] Formula (2): Z = λ ÷ √ε r ×0.5×Y

[0110] In the formula, λ is the wavelength of the above radio wave in vacuum, ε r is the relative dielectric constant of each layer at the frequency of the above-mentioned radio wave, and Y is an integer greater than or equal to 1.

[0111] According to the method disclosed in the present invention, it is possible to manufacture a radio wave transmitting member that suppresses attenuation of transmitted radio waves.

[0112] The details and preferred embodiments of the radio wave transmitting member manufactured by the method of the present disclosure are the same as the details and preferred embodiments of the radio wave transmitting member of the present disclosure described above.

[0113] <Automotive Parts>

[0114] The automobile component of the present disclosure is an automobile component including the above-mentioned radio wave transmitting member.

[0115] The type of automobile parts is not particularly limited, and may be any interior or exterior parts of an automobile.

[0116] Examples of automotive parts include Figure 2 The front part of the vehicle shown in the example, Figure 3 The parts from the side to the rear of the car as shown in the example and Figure 4 Such automobile interior parts are exemplified.

[0117] Specific examples of automobile parts include: Figure 2 The emblem 102 , lights 104 , trim 106 , bumper 108 , and grille 110 are shown; Figure 3 Lights 202 , rear doors 204 , trim 206 , exterior mirrors 208 , exterior door handles 210 , and bumper 212 are shown; Figure 4 The interior lights 302 , the ceiling molding 304 , the interior rearview mirror 306 , the instrument panel molding 308 , the door trim 310 and the like are shown.

[0118] Automobile parts may also have sensing functions such as obstacle sensors, human body sensors, and vital sign sensors.

[0119] <Logo>

[0120] The sign disclosed in the present invention is a sign including the above-mentioned radio wave transmitting member.

[0121] The sign of the present disclosure suppresses attenuation of the transmitted radio waves. Therefore, for example, even if the sign is installed in front of a car equipped with a radio wave transceiver, the radio wave transmission and reception function can be well maintained.

[0122] The logo of the present disclosure is mounted on a vehicle body in such a manner that the outer layer side of the radio wave transmitting member faces the outer side.

[0123] The outer layer side of the logo may have a concave-convex shape for expressing characters, designs, etc.

[0124] <Object Detection Structure>

[0125] The object detection structure disclosed in the present invention comprises the above-mentioned radio wave transmission member and a device for irradiating radio waves to the above-mentioned radio wave transmission member. The object detection structure disclosed in the present invention exhibits excellent object detection performance because radio wave attenuation caused by the radio wave transmission member is suppressed.

[0126] The object detection structure disclosed in the present disclosure can be suitably used in, for example, an automatic collision avoidance system of an automobile (preferably an automatic collision avoidance system using millimeter waves).

[0127] Example

[0128] Hereinafter, the present disclosure will be described in more detail by way of examples, but the present disclosure is not limited to the following examples.

[0129] (Sample production)

[0130] A radio wave transmitting member sample was prepared using a polycarbonate plate having a relative dielectric constant of 2.574 at 77 GHz as an outer layer or inner layer and a space (air) provided between the polycarbonate plates as an intermediate layer. The thickness of each layer was adjusted to the value shown in Table 2.

[0131] (Measurement of radio wave attenuation)

[0132] The sample was irradiated with radio waves having a frequency of 77 GHz and a wavelength of 3.893409 mm in vacuum from the inner layer side perpendicularly to the thickness direction, and the radio wave attenuation was measured using a free space method.

[0133] (Determination of Absorption and Reflectance)

[0134] The sample was irradiated with radio waves having a frequency of 77 GHz and a wavelength of 3.893409 mm in vacuum from the inner layer side perpendicularly to the thickness direction, and the absorptivity and reflectivity of the radio waves were measured using a free space method.

[0135] The smaller the total value of the radio wave absorption rate and the reflection rate is, the greater the radio wave transmittance is.

[0136] [Table 2]

[0137]

[0138] In the items of “X” in the table, “OK” means that the thickness X of the corresponding layer satisfies the equations (1) and (2), and “NG” means that the thickness X of the corresponding layer does not satisfy the equations (1) and (2).

[0139] As shown in Table 2, samples 1 to 9 in which the thickness X of the outer layer and the inner layer in the radio wave transmission direction respectively satisfy equations (1) and (2) have a lower radio wave attenuation than samples 10 to 16 that do not satisfy these conditions. Furthermore, even if the thickness X of the intermediate layer is not designed to satisfy equations (1) and (2), the radio wave attenuation is effectively suppressed.

Claims

1. A radio wave transmitting member comprising an outer layer, an intermediate layer and an inner layer in this order, The radio wave transmitting member has a region in which the thicknesses X of the outer layer and the inner layer in the radio wave transmitting direction satisfy the following equations (1) and (2), respectively: Formula (1) Z-0.3mm≤X≤Z+0.3mm Formula (2) Z=λ÷√ε r ×0.5×Y In the formula, λ is the wavelength of the radio wave in vacuum, ε r is the relative dielectric constant of each layer at the frequency of the radio wave, and Y is an integer greater than or equal to 1.

2. The radio wave transmitting member according to claim 1, wherein in the region, a thickness X of the intermediate layer satisfies the above-mentioned formula (1) and formula (2). The radio wave transmitting member according to claim 1 , wherein the intermediate layer is an air layer. 4 . The radio wave transmitting member according to claim 1 , wherein the outer layer and the inner layer each contain a resin. The radio wave transmitting member according to claim 1 , further comprising a metal layer capable of transmitting the radio wave. 6 . The radio wave transmitting member according to claim 5 , wherein the metal layer is provided between the outer layer and the intermediate layer or between the inner layer and the intermediate layer. 7 . The radio wave transmitting member according to claim 1 , which is used to transmit radio waves having a frequency of 20 GHz to 300 GHz.

8. A method for manufacturing a radio wave transmitting member, the radio wave transmitting member comprising an outer layer, an intermediate layer and an inner layer in sequence, the manufacturing method comprising: The thicknesses of the outer layer and the inner layer are determined so that the thicknesses X of the outer layer and the inner layer in the radio wave transmission direction satisfy the following equations (1) and (2), respectively. Formula (1) Z-0.3mm≤X≤Z+0.3mm Formula (2) Z=λ÷√ε r ×0.5×Y In the formula, λ is the wavelength of the radio wave in vacuum, ε r is the relative dielectric constant of each layer at the frequency of the radio wave, and Y is an integer greater than or equal to 1. 9 . An automobile component comprising the radio wave transmitting member according to claim 1 . 10 . A marker comprising the radio wave transmitting member according to claim 1 . 11 . An object detection structure comprising the radio wave transmitting member according to claim 1 , and a device for irradiating the radio wave to the radio wave transmitting member.

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