Radio wave transmission member, automobile component, emblem, and object detection structure

Abstract

This radio wave transmission member includes an outer member, an inner member, and a metal layer that can transmit radio waves and that is disposed between the outer member and the inner member. At least one of the outer member and the inner member has a light diffusion function.

Description

Radio wave transmitting materials, automotive parts, emblems and object detection structures

[0001] The present disclosure relates to a radio wave transparent member, an automobile part, an emblem, and an object detection structure.

[0002] Recent advances in automobile safety devices have been remarkable, and automatic collision avoidance systems, for example, have become commonplace. Automatic collision avoidance systems automatically apply the brakes based on image data from an onboard camera and information about the relative distance to an object obtained using a radio wave transmitter and receiver, such as a millimeter wave transmitter.

[0003] The radio wave transmitter and receiver that make up the automatic collision avoidance system is preferably located at the front center of the vehicle, where the vehicle emblem is usually located. Therefore, a configuration combining the vehicle emblem with the radio wave transmitter and receiver has been proposed.

[0004] Automobile emblems generally have a structure in which a metal layer for expressing metallic luster is formed on a base material such as resin, etc. For example, Patent Documents 1 and 2 disclose structures in which a metal layer is formed on a base material by silver mirror reaction as an emblem that has metallic luster and is capable of transmitting radio waves.

[0005] Patent Document 1: JP 2003-019765 A Patent Document 2: JP 2019-177311 A

[0006] The appearance is an important element of an automobile, and emblems are expected to play a role as a means of expressing the automobile's design. In view of the above circumstances, the present disclosure aims to provide a radio wave transparent member, an automobile part, an emblem, and an object detection structure that are capable of transmitting radio waves and have excellent design.

[0007] Means for achieving the above object include the following embodiments. <1> A radio wave transparent member comprising an outer member, an inner member, and a metal layer capable of transmitting radio waves and disposed between the outer member and the inner member, wherein at least one of the outer member and the inner member has a light diffusing function. <2> The radio wave transparent member according to <1>, wherein the outer member and the inner member each contain a resin. <3> The radio wave transparent member according to <1> or <2>, wherein at least one of the outer member and the inner member contains light diffusing particles. <4> The radio wave transparent member according to any one of <1> to <3>, wherein the metal layer is capable of transmitting visible light. <5> The radio wave transparent member according to any one of <1> to <4>, for transmitting radio waves having a frequency of 20 GHz to 300 GHz. <6> An automotive part comprising the radio wave transparent member according to any one of <1> to <5>. <7> An emblem comprising the radio wave transparent member according to any one of <1> to <5>. <8> An object detection structure comprising: a radio wave transparent member having an outer member, a metal layer that can transmit radio waves, and an inner member; a device that irradiates radio waves from behind the radio wave transparent member toward the radio wave transparent member; and a light source that irradiates light from the side of the radio wave transparent member toward the radio wave transparent member.

[0008] According to the present disclosure, there are provided a radio wave transparent member, an automobile part, an emblem, and an object detection structure that are capable of transmitting radio waves and have excellent design properties.

[0009] Fig. 1 is a schematic cross-sectional view showing an example of the configuration of a radio wave transparent member; Fig. 2 is a schematic plan view showing an example of the configuration of a radio wave transparent member; Fig. 3 is a schematic view showing an example of an automobile part including a radio wave transparent member; Fig. 4 is a schematic view showing an example of an automobile part including a radio wave transparent member; Fig. 5 is a schematic view showing an example of an automobile part including a radio wave transparent member.

[0010] Hereinafter, embodiments for carrying out the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, components (including element steps, etc.) are not essential unless otherwise specified. The same applies to numerical values ​​and their ranges, and do not limit the present disclosure.

[0011] In the present disclosure, numerical ranges indicated using "to" include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in the present disclosure, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another staged numerical range. Furthermore, in numerical ranges described in the present disclosure, the upper or lower limit value of that numerical range may be replaced with a value shown in the examples. In the present disclosure, each component may contain multiple corresponding substances. When multiple substances corresponding to each component are present in a composition, the content or amount of each component means the total content or amount of the multiple substances present in the composition, unless otherwise specified. In the present disclosure, particles corresponding to each component may contain multiple types of particles. In the present disclosure, the terms "layer" and "film" include cases where the layer or film is formed over the entire region when the region where the layer or film is present is observed, as well as cases where the layer or film is formed only in a portion of the region. When embodiments are described in the present disclosure with reference to drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. Furthermore, the sizes of the components in each drawing are conceptual, and the relative relationships between the sizes of the components are not limited to these.

[0012] <Radio wave transparent member> The radio wave transparent member of the present disclosure comprises an outer member, an inner member, and a metal layer that is disposed between the outer member and the inner member and that is capable of transmitting radio waves, and at least one of the outer member and the inner member has a light diffusion function.

[0013] The radio wave transparent member of the present disclosure has a metal layer between the outer member and the inner member that is capable of transmitting radio waves. By disposing the metal layer between the outer member and the inner member that is capable of transmitting radio waves, a metallic luster is imparted to the radio wave transparent member without impeding the transmission of radio waves. Furthermore, at least one of the outer member and the inner member has a light diffusion function, which allows the radio wave transparent member to emit light. This enables various expressions using light. Furthermore, at least one of the outer member and the inner member has a light diffusion function, which allows the radio wave transparent member to emit light sufficiently even when light is irradiated from a direction different from the direction of incidence of radio waves onto the radio wave transparent member. Therefore, a light source can be placed in a position (e.g., a side of the radio wave transparent member) that does not compete with a radio wave transmitter / receiver.

[0014] In the present disclosure, an "outer member" is a member located on the opposite side of the radio wave-transmitting member from the device that irradiates radio waves, and an "inner member" is a member located on the opposite side of the device that irradiates radio waves to the radio wave-transmitting member.

[0015] Fig. 1 is a cross-sectional view schematically illustrating an example of the configuration of a radio wave transparent member. In the radio wave transparent member 10 shown in Fig. 1, an outer member 1 and an inner member 2 are arranged to face each other. In the radio wave transparent member 10, a metal layer (not shown) arranged between the outer member 1 and the inner member 2 is arranged, for example, on the surface of the outer member 1 facing the inner member 2.

[0016] Fig. 2 is a schematic plan view showing an example of the configuration of a radio wave transparent member 10 when observed from the outer member 1 side. The radio wave transparent member 10 shown in Fig. 2 has a pattern 3 of any shape. In order to impart metallic luster to the pattern 3, a metal layer that is permeable to radio waves may be provided in a region corresponding to the pattern 3 between the outer member 1 and the inner member 2. The pattern 3 may have a three-dimensional shape. For example, by providing the pattern 3 in a concave shape on the surface of the outer member 1 facing the inner member 2, it is possible to impart a convex three-dimensional appearance to the pattern 3 observed from the outer member 1 side.

[0017] (Outer Member and Inner Member) From the viewpoint of the balance between the strength and radio wave transmittance of the radio wave transmitting member, it is preferable that the outer member and the inner layer each be a layer containing a resin.

[0018] Resins that can be contained in the outer member and the inner member include thermosetting resins, thermoplastic resins, and synthetic rubbers.

[0019] Examples of thermoplastic resins include polyethylene (PE), polypropylene (PP), polycarbonate (PC), polystyrene, polyvinyl chloride, vinyl polymers, polyester, polyamide, acrylonitrile-butadiene-styrene copolymer resin (ABS resin), (meth)acrylic resin, acrylonitrile-ethylene-propylene-diene-styrene copolymer resin (AES resin), and thermoplastic elastomer.

[0020] Examples of the thermosetting resin include silicone resin, urethane resin, melamine resin, epoxy resin, phenol resin, and urea resin.

[0021] Examples of synthetic rubber include ethylene-propylene-diene rubber (EPDM), acrylonitrile-butadiene rubber (NBR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), silicone rubber, and urethane rubber.

[0022] Among the above-mentioned resins, PC, PP, ABS resin, (meth)acrylic resin, and AES resin are preferred, and PC, (meth)acrylic resin, and AES resin are more preferred. PC has high impact resistance, excellent heat resistance, and high transparency. PC is also easy to process, and is relatively light and strong among resins. (Meth)acrylic resin has high transparency and excellent weather resistance. AES resin has high rigidity and excellent weather resistance.

[0023] When the outer member and the inner member each contain a resin, the outer member and the inner member may contain only resin, or may contain resin and a component other than resin. Examples of components other than resin include inorganic particles, colorants, antistatic agents, and the light-diffusing particles described below. When the outer member and the inner member each independently contain resin and a component other than resin, the resin content in the outer member and the inner member is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more. The upper limit of the resin content is not particularly limited as long as it is less than 100% by mass.

[0024] At least one of the outer member and the inner member has a light diffusing function. Methods for imparting the light diffusing function to at least one of the outer member and the inner member include a method of incorporating light diffusing particles, a method of forming irregularities on the surface, etc. The outer member or inner member having a light diffusing function may have the light diffusing function entirely or partially.

[0025] Among the above methods, the method of incorporating light-diffusing particles is preferred from the viewpoint of productivity. Examples of light-diffusing particles include resin particles such as acrylic resin particles, silicone resin particles, methyl methacrylate particles, styrene-methyl methacrylate particles, and methyl methacrylate-butadiene-styrene particles, and inorganic particles such as titanium oxide particles, silica particles, zirconia particles, zinc oxide particles, and alumina particles. The light-diffusing particles may be used alone or in combination of two or more types.

[0026] When the outer member or the inner member contains light diffusing particles, the content of the light diffusing particles is not particularly limited. For example, the content of the light diffusing particles may be 3% by mass to 20% by mass of the entire outer member or the inner member.

[0027] (Metal Layer) A metal layer that is transmissive to radio waves is disposed between the outer member and the inner member. The metal layer may be disposed on the surface of the outer member facing the inner member or on the surface of the inner member facing the outer member. From the viewpoint of obtaining a good metallic luster, it is preferable that the metal layer be disposed on the surface of the outer member facing the inner member.

[0028] The metal layer may be capable of transmitting visible light. When the metal layer is capable of transmitting visible light, the region of the electron transparent member where the metal layer is disposed can be made to emit light by the transmission of visible light.

[0029] An example of a metal layer that is permeable to radio waves is a film containing metal particles. When the metal particles are contained in the film, radio waves can pass through the gaps between the metal particles.

[0030] The metal layer may be a metal layer containing silver particles. The metal layer containing silver particles can be formed, for example, by silver mirror reaction. An example of a method for forming a metal layer by silver mirror reaction is a method in which an aqueous ammoniacal silver nitrate solution is brought into contact with an aqueous reducing agent solution on a substrate. This causes an oxidation-reduction reaction, resulting in the precipitation of silver particles, and a metal layer containing silver particles is formed on the substrate. When a metal layer is provided on an outer member or an inner member by the above method, the outer member or the inner member may be used as the substrate.

[0031] From the viewpoint of radio wave transmission, the thickness of the metal layer is preferably 1000 nm or less, more preferably 500 nm or less, and even more preferably 100 nm or less. From the viewpoint of imparting sufficient metallic luster to the radio wave transmission member, the thickness of the metal layer is preferably 10 nm or more.

[0032] When a metal layer is provided on an outer member or an inner member, an undercoat layer may be provided between the outer member or the inner member and the metal layer to improve adhesion between the outer member or the inner member and the metal layer, or a protective layer may be provided on the metal layer to protect the surface of the metal layer.

[0033] The undercoat layer or protective layer may be a layer containing a resin, and examples of the resin include fluororesin, polyester resin, epoxy resin, melamine resin, silicone resin, acrylic silicone resin, and acrylic urethane resin.

[0034] The thickness of the undercoat layer or the protective layer is preferably 1 μm to 50 μm, and when the thickness of the undercoat layer or the protective layer is 1 μm to 50 μm, attenuation of the radio wave transmission amount by the undercoat layer or the protective layer is sufficiently suppressed.

[0035] The thickness of the radio wave transparent member is not particularly limited and can be set depending on the shape of the radio wave transparent member, the wavelength of the radio waves that are transmitted through the radio wave transparent member, etc. For example, the maximum thickness in the thickness direction of the electron transparent member may be 2.1 mm to 36.0 mm, 3.3 mm to 28.0 mm, or 4.5 mm to 22.0 mm.

[0036] In the present disclosure, the thickness of the radio wave transparent member can be measured by a known method. For example, the thickness may be measured by observing a cut surface of the radio wave transparent member, or may be measured using a microtome or the like.

[0037] The type of radio wave that can be transmitted through the radio wave transparent member is not particularly limited, and may be, for example, a millimeter wave. In the present disclosure, "millimeter wave" refers to a radio wave having a frequency of 20 GHz to 300 GHz. The radio wave transparent member of the present disclosure is particularly useful for reducing the transmission attenuation of millimeter waves.

[0038] <Automotive Parts> The automotive parts of the present disclosure are automotive parts including the radio wave transparent member described above. The type of automotive part is not particularly limited and may be any interior or exterior automotive part. Examples of automotive parts include parts in the front portion of the automobile as illustrated in FIG. 3 , parts in the side and rear portions of the automobile as illustrated in FIG. 4 , and interior automotive parts as illustrated in FIG. 5 . Specific examples of automotive parts include the emblem 102, lamp 104, garnish 106, bumper 108, and grille 110 shown in FIG. 3 ; the lamp 202, tailgate 204, garnish 206, outer mirror 208, door outer handle 210, and bumper 212 shown in FIG. 4 ; and the room lamp 302, roof garnish 304, room mirror 306, instrument panel garnish 308, and door trim 310 shown in FIG. 5 . The automotive parts may have sensing functions such as obstacle sensors, human presence sensors, and vital signs sensors.

[0039] <Emblem> The emblem of the present disclosure includes the radio wave-transmitting member described above. The emblem of the present disclosure has the function of transmitting radio waves. Therefore, even if the emblem is attached to the front of a vehicle equipped with a radio wave transmitter / receiver, the radio wave transmission and reception function is maintained satisfactorily.

[0040] The emblem of the present disclosure is attached to the body of an automobile so that the outer member of the radio wave transparent member is on the outside.

[0041] <Object detection structure> The object detection structure of the present disclosure comprises a radio wave transparent member having an outer member, a metal layer that is permeable to radio waves, and an inner member, a device that irradiates radio waves from behind the radio wave transparent member toward the radio wave transparent member, and a light source that irradiates light from the side of the radio wave transparent member toward the radio wave transparent member.

[0042] The object detection structure disclosed herein includes a light source that irradiates a radio wave transparent member with light. This allows desired portions of the radio wave transparent member to emit light, enabling various expressions using light. Furthermore, in the object detection structure disclosed herein, the light source is provided on the side of the radio wave transparent member. This allows the light source to be positioned without competing with a radio wave irradiator provided behind the radio wave transparent member.

[0043] In this disclosure, the term "rear of the radio wave transparent member" refers to a position corresponding to the rear of the inner member when the radio wave transparent member is observed from the outer member side. In this disclosure, the term "side of the radio wave transparent member" refers to a position corresponding to the outside of the outline of the radio wave transparent member when the radio wave transparent member is observed from the outer member side.

[0044] The type of light source used in the object detection structure of the present disclosure is not particularly limited. From the viewpoints of safety and economy, a light-emitting diode (LED) is preferred. The color, flashing pattern, etc. of the light emitted from the light source are not particularly limited and can be selected according to the desired effect. The location of the light source is not particularly limited as long as it is on the side of the radio wave transparent member, and may be one location or two or more locations.

[0045] In the radio wave transparent member used in the object detection structure of the present disclosure, at least one of the outer member and the inner member may have a light diffusion function (i.e., may be the radio wave transparent member described above), or may not have a light diffusion function. From the viewpoint of efficiently emitting light from the radio wave transparent member, it is preferable that at least one of the outer member and the inner member has a light diffusion function. Preferred aspects of each member constituting the radio wave transparent member are the same as the preferred aspects of each member constituting the radio wave transparent member described above.

[0046] The object detection structure of the present disclosure can be suitably used, for example, in an automatic collision avoidance system for automobiles (preferably, an automatic collision avoidance system that uses millimeter waves).

Claims

1. A radio wave transparent member comprising an outer member, an inner member, and a metal layer capable of transmitting radio waves that is disposed between the outer member and the inner member, wherein at least one of the outer member and the inner member has a light diffusion function.

2. The radio wave transparent member according to claim 1, wherein the outer member and the inner member each contain a resin.

3. The radio wave transparent member according to claim 1, wherein at least one of the outer member and the inner member contains light diffusing particles.

4. The radio wave transparent member according to claim 1, wherein the metal layer is capable of transmitting visible light.

5. The radio wave transparent member according to any one of claims 1 to 4, for transmitting radio waves having a frequency of 20 GHz to 300 GHz.

6. An automobile part comprising the radio wave transparent material according to any one of claims 1 to 5.

7. An emblem comprising the radio wave transparent material according to any one of claims 1 to 5.

8. An object detection structure comprising: a radio wave transparent member having an outer member, a metal layer capable of transmitting radio waves, and an inner member; a device that irradiates radio waves toward the radio wave transparent member from behind the radio wave transparent member; and a light source that irradiates light toward the radio wave transparent member from the side of the radio wave transparent member.

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