WO2023037871A1

WO2023037871A1 - Radio wave transmissive member, emblem, and target detection structure

Info

Publication number: WO2023037871A1
Application number: PCT/JP2022/031756
Authority: WO
Inventors: 博文塩川
Original assignee: 株式会社レゾナック
Priority date: 2021-09-08
Filing date: 2022-08-23
Publication date: 2023-03-16
Also published as: JP2023039302A

Abstract

Provided is a radio wave transmissive member having an outer member, an inner member, and a heat generation layer that generates heat by the passage of electric current, wherein the heat generation layer is disposed directly on a surface of the outer member that faces the inner member or a surface of the inner member that faces the outer member.

Description

Radio wave transmission member, emblem and object detection structure

The present disclosure relates to radio wave transmission members, emblems, and object detection structures.

Automobiles in recent years have made remarkable advances in safety equipment, and for example, automatic collision avoidance systems have become commonplace.
The automatic collision avoidance system automatically applies the brakes based on the image data of the on-board camera and the relative distance information to the object obtained using the millimeter wave radar.

It is desirable to place the millimeter-wave transmitter and receiver that make up the automatic collision avoidance system in the front center of the car. An automobile emblem is generally placed in the front center of the automobile. Therefore, a configuration has been proposed in which an automobile emblem and a millimeter-wave transmitter/receiver are combined.

If ice and snow adhere to the emblem, which has a millimeter wave transmission/reception function, the amount of transmission of the millimeter wave may decrease, resulting in a drop in transmission/reception performance. Therefore, for example, Patent Document 1 describes an emblem in which a metal conductive wire that generates heat when energized is arranged in order to melt the ice and snow adhering to the emblem.

JP 2003-019765 A

The emblem described in Patent Literature 1 has a limited degree of freedom in design due to the arrangement of metal conductors inside.
In view of the above circumstances, an object of the present disclosure is to provide a radio wave transmitting member, an emblem, and an object detection structure that have a heat generating function and are excellent in design freedom.

Means for achieving the above objects include the following embodiments.
<1> An outer member, an inner member, and a heat-generating layer that generates heat when energized, wherein the heat-generating layer is the surface of the outer member facing the inner member or the surface of the inner member facing the outer member A radio wave transparent member placed directly on the
<2> The radio wave transmission member according to <1>, wherein the outer member and the inner member each contain a resin.
<3> The radio wave transmitting member according to <1> or <2>, wherein the heating layer has PTC characteristics.
<4> The radio wave transmitting member according to any one of <1> to <3>, further comprising a metal layer capable of transmitting radio waves.
<5> The radio wave transmitting member according to any one of <1> to <4>, for transmitting radio waves having a frequency of 20 GHz to 300 GHz.
<6> An emblem including the radio wave transmitting member according to any one of <1> to <5>.
<7> An object detection structure comprising: the radio wave transmitting member according to any one of <1> to <5>; and a device for radiating radio waves toward the radio wave transmitting member.

According to the present disclosure, a radio wave transmitting member, an emblem, and an object detection structure that have a heat generating function and are excellent in design freedom are provided.

FIG. 2 is a schematic cross-sectional view showing an example of the configuration of a radio wave transmitting member; FIG. 3 is a schematic plan view showing an example of the configuration of a radio wave transmitting member; FIG. 3 is a schematic plan view showing an example of the configuration of a radio wave transmitting member;

A detailed description will be given below of the embodiment for implementing the present disclosure. However, the present disclosure is not limited to the following embodiments. In the following embodiments, the constituent elements (including element steps and the like) are not essential unless otherwise specified. The same applies to numerical values and their ranges, which do not limit the present disclosure.

In the present disclosure, the numerical range indicated using "-" includes the numerical values before and after "-" as the minimum and maximum values, respectively.
In the numerical ranges described step by step in the present disclosure, the upper limit or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described step by step. . Moreover, in the numerical ranges described in the present disclosure, the upper or lower limits of the numerical ranges may be replaced with the values shown in the examples.
In the present disclosure, each component may contain multiple types of applicable substances. When there are multiple types of substances corresponding to each component in the composition, the content rate or content of each component is the total content rate or content of the multiple types of substances present in the composition unless otherwise specified. means quantity.
In the present disclosure, the particles corresponding to each component may include multiple types of particles.
In the present disclosure, the term “layer” or “film” refers to the case where the layer or film is formed in the entire region when observing the region where the layer or film is present, and only a part of the region. It also includes the case where it is formed.

<Radio wave transmission member>
A radio wave transmitting member of the present disclosure includes an outer member, an inner member, and a heat generating layer that generates heat when energized. It is a radio wave transmitting member that is placed directly on the surface facing the member.

The radio wave transmitting member of the present disclosure has a heat generating layer that generates heat when energized on the surface of the outer member on the inner member side or on the surface of the inner member on the outer member side. By causing the heating layer to generate heat by energization, it is possible to melt the ice and snow adhering to the radio wave transmitting member, thereby suppressing a decrease in radio wave transmittance.
Furthermore, the heat-generating layer is directly disposed on the surface of the outer member facing the inner member or the surface of the inner member facing the outer member. In other words, there is no need to arrange a conductive wire or the like inside the radio wave transmitting member, and the degree of freedom in design is excellent.

In the present disclosure, the "outer member" is a member on the opposite side of the radio wave transmitting member from the side facing the device that radiates radio waves, and the "inner member" is the side that faces the device that radiates radio waves on the radio wave transmitting member. It is a member.

FIG. 1 is a cross-sectional view schematically showing an example of the configuration of a radio wave transmitting member.
The radio wave transmitting member shown in FIG. 1 has an outer member 1 and an inner member 3 arranged so as to face each other, and transmits radio waves emitted from a radio wave emitting device (not shown) and reflects radio waves from an object. permeate the radio waves
A heat-generating layer (not shown) is directly disposed on the surface of the outer member 1 facing the inner member 3 or the surface of the inner member 3 facing the outer member 1 . Between the outer member 1 and the inner member 3, there is a space 2 in which members other than the heat generating layer can be arranged.

2 and 3 are schematic plan views showing an example of the configuration of the radio wave transmitting member, showing a state in which a heat generating layer is arranged on the surface of the inner member facing the outer member. For convenience of explanation, the illustration of the outer member is omitted.

The radio wave transmitting member 10 shown in FIG. 2 includes a heat generating layer 12 arranged on an inner member 11, wiring 13 and electrodes 14 for supplying electricity to the heat generating layer 12, and connectors 15 connecting the wiring 13 and the electrodes 14, respectively. and have

A radio wave transmitting member 20 shown in FIG. 3 is a modification of the radio wave transmitting member 10 shown in FIG. arranged along the inner perimeter.
By arranging the heat-generating layer 22, the wiring 23, the electrodes 24, and the connector 25 along the inner circumference of the inner member 21, for example, it is possible to suppress the transmission of radio waves near the center of the inner member 21 from being obstructed by these members. can.

The radio wave transmitting member shown in FIGS. 2 and 3 has wiring, electrodes and connectors in addition to the heating layer, but these may be omitted as necessary, and other components such as a temperature sensor may be used as necessary. may have parts of
The wiring, electrodes, and connectors may be separately prepared parts mounted on the inner member, or may be arranged directly on the inner member like a heat generating layer. As a method of directly arranging wiring, electrodes or connectors on the inner member, there is a method of applying a composition containing materials constituting each part to the surface of the inner member.

(Outer member and inner member)
From the viewpoint of the balance between the strength and radio wave transparency of the radio wave transmitting member, it is preferable that the outer member and the inner layer each contain a resin.

Thermosetting resins, thermoplastic resins and synthetic rubbers are examples of resins that can be contained in the outer member and the inner member.

Thermoplastic resins include polyethylene, polypropylene, polycarbonate (PC), polystyrene, polyvinyl chloride, vinyl-based polymer, polyester, polyamide, acrylonitrile-butadiene-styrene copolymer resin (ABS resin), (meth)acrylic resin, acrylonitrile. - Ethylene-propylene-diene-styrene copolymer resin (AES resin), thermoplastic elastomer and the like.

Thermosetting resins include silicone resins, urethane resins, melamine resins, epoxy resins, phenol resins, and urea resins.

Synthetic rubbers 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 , urethane rubber, and the like.

Among the resins mentioned above, PC, polypropylene, ABS resin, (meth)acrylic resin and AES resin are preferable, and PC, (meth)acrylic resin and AES resin are more preferable. PC has high impact resistance, excellent heat resistance, and high transparency. In addition, PC is easy to process, relatively light among resins, and strong. (Meth)acrylic resins have high transparency and excellent weather resistance. AES resin has high rigidity and excellent weather resistance.

When the outer member and the inner member respectively contain a resin, the outer member and the inner member may contain only the resin, or may contain the resin and components other than the resin.
Components other than the resin include inorganic particles, colorants, antistatic agents, and the like.
When the outer member and the inner member each independently contain a resin and a component other than the resin, the content of the resin contained in the outer member and the inner member is preferably 60% by mass or more, and is 70% by mass or more. is more preferable, more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

The thicknesses of the outer member and the inner member are not particularly limited, and can be set according to the use of the radio wave transmitting member, the wavelength of the radio wave transmitted through the radio wave transmitting member, and the like.
The thickness of the outer member may be 1.5 mm to 6.0 mm, 1.8 mm to 4.5 mm, or 2.0 mm to 4.0 mm.
The thickness of the inner member may be 1.5 mm to 6.0 mm, 1.8 mm to 5.5 mm, or 2.0 mm to 5.0 mm.

When a space exists between the outer member and the inner member, the thickness of the space may be 0.1 mm to 3.0 mm, 0.3 mm to 1.5 mm, or 0.5 mm to It may be 1.0 mm.

In the present disclosure, the thickness of the outer member, the inner member, and the space between the outer member and the inner member means the dimension in the thickness direction of the radio wave transmitting member.
In the present disclosure, the thickness of the outer member, the inner member, and the space between the outer member and the inner member can be measured by known methods. For example, it may be measured by observing a cut surface of the radio wave transmitting member, or may be measured using a microtome or the like.

(heat generating layer)
The heat generating layer is arranged directly on the surface of the outer member facing the inner member or the surface of the inner member facing the outer member.
In the present disclosure, “directly arranged” means that the heat generating layer is in a state of being in close contact with the surface of the outer member or the inner member (that is, a state of being arranged without interposing a space or another member). .
The position of the heat generating layer on the surface of the outer member facing the inner member or the surface of the inner member facing the outer member is not particularly limited, and can be selected according to the shape of the radio wave transmitting member.

The method of arranging the heat generating layer on the surface of the outer member or inner member is not particularly limited. For example, there is a method of applying a material for forming the heat generating layer to the surface of the outer member or the inner member. Specific examples include a method of applying a liquid or paste material to the surface of the outer member or the inner member, and a method of attaching a sheet-like material to the surface of the outer member or the inner member.

The thickness of the heat-generating layer is not particularly limited, and can be set according to the desired heat-generating performance. For example, the heat generation layer may have a thickness of 10 μm to 300 μm.

The material of the heat generating layer is not particularly limited as long as it has the property of generating heat when energized. Examples thereof include conductive materials such as metals, carbon, and semiconducting ceramics.
If necessary, the heat-generating layer may contain materials other than the conductive material, such as binders and fillers.

The heat generating layer preferably has PTC (Positive Temperature Coefficient) characteristics.
In the present disclosure, the PTC characteristic means the property that when the temperature is low, the resistance value is small and current flows easily, and as the temperature rises, the resistance value increases and the current becomes difficult to flow.
If the heat generating layer has a PTC characteristic, for example, in a low temperature environment, the heat generating layer generates heat and the temperature of the radio wave transmitting member rises. Suppressed. As a result, excessive heat generation is suppressed, and power consumption can be saved.
Materials having PTC properties include, for example, semiconductor ceramics obtained by adding a trace amount of rare earth elements to ferroelectric barium titanate (BaTiO ₃ ).

(metal layer)
The radio wave transmitting member may include a metal layer that can transmit radio waves. By providing the radio wave transmitting member with a metal layer capable of transmitting radio waves, the radio wave transmitting member can be given a metallic luster.

When the radio wave transmitting member includes a metal layer capable of transmitting radio waves, the metal layer may be arranged on the surface of the outer member facing the inner member or the surface of the inner member facing the outer member.
The metal layer may be arranged on the surface of the outer member facing the inner member or the surface of the inner member facing the outer member, the surface on which the heat generating layer is not arranged.
From the viewpoint of the appearance of the radio wave transmitting member, the metal layer is preferably arranged on the surface of the outer member facing the inner member.

A metal layer that can transmit radio waves includes a film containing metal particles. When the metal particles contain the metal particles, radio waves can pass through the gaps between the metal particles.

The metal layer may be a metal layer containing silver particles. A metal layer containing silver particles can be formed by, for example, a silver mirror reaction.
A method of forming a metal layer by a silver mirror reaction includes a method of bringing an ammoniacal silver nitrate aqueous solution and a reducing agent aqueous solution into contact on a substrate. This causes an oxidation-reduction reaction to deposit silver particles, forming a metal layer containing silver particles on the substrate.
When the metal layer is provided on the outer member or the inner member by the above method, the outer member or the inner member may be used as the base material.

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 transmitting member, the thickness of the metal layer is preferably 10 nm or more.

When a metal layer is provided on the outer member or inner member, an undercoat layer may be provided between the outer member or inner member and the metal layer in order to increase the adhesion between the outer member or inner member and the metal layer. good.
Alternatively, a protective layer may be provided on the metal layer to protect the surface of the metal layer.

The undercoat layer or protective layer includes a layer containing a resin, and the resin includes fluorine resin, polyester resin, epoxy resin, melamine resin, silicone resin, acrylic silicone resin, acrylic urethane resin, and the like.

The thickness of the undercoat layer or protective layer is preferably 1 μm to 50 μm independently. When the thickness of the undercoat layer or protective layer is 1 μm to 50 μm, attenuation of radio wave transmission due to the undercoat layer or protective layer is sufficiently suppressed.

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

<Emblem>
An emblem of the present disclosure is an emblem including the radio wave transmitting member described above.
The emblem of the present disclosure has a function of transmitting radio waves. Therefore, for example, even if the emblem is attached to the front of an automobile equipped with a radio wave transmitter/receiver, the radio wave transmitting/receiving function can be maintained satisfactorily.

The emblem of the present disclosure is attached to the vehicle body of an automobile so that the outer member side of the radio wave transmitting member faces outward.
The emblem may have a concavo-convex shape for expressing characters, designs, and the like.

<Object detection structure>
The object detection structure of the present disclosure includes the above-described radio wave transmitting member and a device that emits radio waves toward the radio wave transmitting member.

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 using millimeter waves).

The disclosure of Japanese Patent Application No. 2021-146416 is incorporated herein by reference in its entirety. All publications, patent applications and technical standards mentioned herein are to the same extent as if each individual publication, patent application and technical standard were specifically and individually noted to be incorporated by reference. incorporated herein by reference.

Claims

It has an outer member, an inner member, and a heat-generating layer that generates heat when energized, and the heat-generating layer is provided on the surface of the outer member facing the inner member or on the surface of the inner member facing the outer member. A radio wave transmitting member that is directly placed.
The radio wave transmitting member according to claim 1, wherein the outer member and the inner member each contain a resin.
The radio wave transmitting member according to claim 1 or 2, wherein the heat generating layer has PTC characteristics.
The radio wave transmitting member according to any one of claims 1 to 3, further comprising a metal layer capable of transmitting radio waves.
The radio wave transmitting member according to any one of claims 1 to 4, for transmitting radio waves having a frequency of 20 GHz to 300 GHz.
An emblem including the radio wave transmitting member according to any one of claims 1 to 5.
An object detection structure comprising: the radio wave transmitting member according to any one of claims 1 to 5; and a device for radiating radio waves toward the radio wave transmitting member.