Laminated structure

Abstract

[Problem] To provide a laminated structure capable of effectively reducing a transmission attenuation amount of an electromagnetic wave. [Solution] A laminated structure is interposed in an emission direction of an electromagnetic wave W of a radar device 100 for measuring a physical amount with a detection object by transmitting and receiving the electromagnetic wave, the laminated structure including: a base material 20 that comprises a resin material; and, on the opposite side of the radar device 100 across the base material 20, at least one negative dielectric material layer 30 and at least one coating film layer 10 that includes a color base layer 11 having a colored pigment and / or a bright pigment.

Description

Laminated structure

[0001] The present invention relates to a laminated structure having transparency to electromagnetic waves such as millimeter waves.

[0002] In recent years, research and practical application of autonomous vehicle driving has been progressing using radar devices that use microwaves, millimeter waves, etc., which can provide high resolution. Because this type of radar device is installed on the back side of vehicle body parts (front bumper, rear bumper, etc.), the relevant body parts must have low transmission attenuation of electromagnetic waves.

[0003] The following Patent Document 1 discloses an electromagnetic wave frequency selective transmission material having a conductor pattern and at least one of an adhesive region and a pressure-sensitive adhesive region for holding the conductor pattern to an adherend, and a vehicle component using the same, in order to reduce the amount of electromagnetic wave transmission attenuation described above while enabling easy installation on the outer surfaces of vehicle components of a wide variety of shapes, such as bumpers. This electromagnetic wave frequency selective transmission material utilizes metamaterial technology to achieve a frequency selection function that transmits electromagnetic waves of a specific frequency to be propagated by periodically arranging conductor patterns having a specific structure. The electromagnetic wave frequency selective transmission material is adhered to the back side of the vehicle component (the surface facing the radar device).

[0004] Japanese Patent Application Laid-Open No. 2021-82896

[0005] Vehicle body parts such as bumpers are painted on both the surface facing the radar device and the surface opposite the radar device, and metallic pigments containing reflective aluminum flakes or other luster agents are sometimes used to enhance the design. Vehicle parts are sometimes coated multiple times to create a multi-layer coating that gives them a vibrant, deep color for even greater design appeal.

[0006] Suppose the component disclosed in Patent Document 1 is used in a vehicle body part formed of a material that is prone to high electromagnetic wave reflection and high transmission attenuation, such as a metallic paint containing a lustrous material. However, although the component disclosed in Patent Document 1 is expected to be effective in reducing transmission attenuation to some extent, it is unable to completely avoid the effects of the lustrous material, and it is difficult to say that a sufficient effect in reducing transmission attenuation can be achieved.

[0007] At least one embodiment of the present invention has been made in consideration of the above circumstances, and specifically, an object of the present invention is to provide a laminated structure that can effectively reduce the transmission attenuation of electromagnetic waves such as millimeter waves.

[0008] The laminated structure of this embodiment is a laminated structure that is interposed in the direction of emission of electromagnetic waves of a radar device that transmits and receives electromagnetic waves to measure physical quantities of a detection target, and the laminated structure has a substrate made of a resin material, and, on the opposite side of the radar device across the substrate, a coating layer that includes at least one negative dielectric material layer and at least one color base layer that has a color pigment and / or a lustrous pigment.

[0009] According to at least one embodiment of the present invention, it is possible to provide a laminated structure that can effectively reduce the transmission attenuation of electromagnetic waves such as millimeter waves.

[0010] 1 is a schematic cross-sectional view showing a layer structure of a first form of the laminate structure according to the present embodiment; FIG. 1 is a schematic cross-sectional view showing a layer structure of a second form of the laminate structure according to the present embodiment; FIG. 1 is a schematic cross-sectional view showing a layer structure of a third form of the laminate structure according to the present embodiment; FIG. 1 is a schematic cross-sectional view showing a layer structure of a fourth form of the laminate structure according to the present embodiment; FIG. 1 is a schematic cross-sectional view showing a layer structure of a fifth form of the laminate structure according to the present embodiment; FIG. 1 is a schematic cross-sectional view showing a layer structure of a sixth form of the laminate structure according to the present embodiment; FIG. 2 is a schematic structural view showing an example of a negative dielectric material layer of the laminate structure according to the present embodiment; FIG. 3 is a schematic structural view showing another example of a negative dielectric material layer of the laminate structure according to the present embodiment; FIG. 4 is a table showing the test results of Example 1 and the specifications of each sample; FIG. 5 is a table showing the test results of Example 2 and the specifications of each sample; FIG. 6 is a table showing the test results of Example 3 and the specifications of each sample; FIG. 7 is a table showing the test results of Example 4 and the specifications of each sample; FIG. 8 is a table showing the test results of Example 5 and the specifications of each sample;

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiments shown here are merely examples for embodying the technical concept of the present invention and are not intended to limit the present invention. Furthermore, all other embodiments, examples, and operational techniques that can be conceived by those skilled in the art without departing from the spirit of the present invention are included within the scope and spirit of the present invention, as well as within the scope of the claims and their equivalents.

[0012] Furthermore, for the convenience of illustration and ease of understanding, the drawings attached to this specification may be represented schematically with the scale, aspect ratio, shape, etc. appropriately changed from the actual product, but these are merely examples and do not limit the interpretation of the present invention.

[0013] The laminated structure 1 according to this embodiment can be suitably used in a vehicle body part (i.e., a front bumper, rear bumper, emblem, etc.) that is disposed opposite an electromagnetic wave transmitting / receiving unit of a radar device 100 that transmits electromagnetic waves W of a predetermined wavelength, such as millimeter waves, to a detection target (not shown) (e.g., a vehicle or obstacle traveling around the vehicle) and receives the reflected waves to measure physical quantities related to the detection target (e.g., travel speed, object distance, etc.). The laminated structure 1 is not particularly limited in its use, and can be applied to, for example, other vehicle body parts that require electromagnetic wave transparency. Furthermore, the laminated structure 1 can also be applied to parts other than vehicle body parts that require electromagnetic wave transparency, such as a component that houses equipment that transmits and receives electromagnetic waves W or that covers and protects at least a portion of the periphery of the equipment.

[0014] The configuration of the laminated structure 1 according to this embodiment will be described.

[0015] As shown in Figures 1 to 6, the laminated structure 1 of this embodiment is composed of a coating layer 10, a substrate 20 which is an object to be coated on which the coating layer 10 is formed, and a negative dielectric material layer 30 which is disposed on the outer surface (layer formation surface) of the coating layer 10 and / or the substrate 20 which is formed on the opposite side of the substrate 20 from the radar device 100.

[0016] In the laminated structure 1, the negative dielectric material layer 30 is disposed so as to be in contact with the coating layer 10 formed on the opposite surface of the radar device 100 across the substrate 20 and the substrate 20. This neutralizes the dielectric constant of the member in contact with the negative dielectric material layer 30. Therefore, the laminated structure 1 can effectively reduce transmission attenuation.

[0017] <Coating Layer> As shown in Figure 1, the coating layer 10 includes at least a color base layer 11. As shown in Figures 2 to 6, the coating layer 10 can have a layer structure including at least one color base layer 11 having a color pigment and / or a luster pigment. As shown in Figures 2 to 6, the coating film 10 can have other layers, such as a primer layer 12 and a clear layer 13, laminated on the layer structure having at least the color base layer 11.

[0018] The coating layer 10 may have a layer structure in which a primer layer 12 is formed under a color base layer 11 (the coating surface that will become the coating surface of the substrate 20) as shown in Fig. 2. The second type of laminated structure 1 has a laminated structure including a coating layer 10 including at least one color base layer 11 and one primer layer 12, a substrate 20, and at least one negative dielectric material layer 30 as shown in Fig. 2.

[0019] The coating layer 10 may have a layer structure in which a clear layer 13 is formed on a color base layer 11 (the outer surface to be painted), as shown in Fig. 3. The third type of laminated structure 1 has a laminate structure including a coating layer 10 including at least one color base layer 11 and one clear layer 13, a substrate 20, and at least one negative dielectric layer 30, as shown in Fig. 3.

[0020] As shown in Fig. 4, the coating layer 10 may have a layer structure including at least one primer layer 12 formed under the color base layer 11 and at least one clear layer 13 formed on the color base layer 11. As shown in Fig. 4, the laminated structure 1 of the fourth embodiment has a laminated structure including the coating layer 10 including at least one color base layer 11, one primer layer 12, and one clear layer 13, a substrate 20, and at least one negative dielectric layer 30.

[0021] As shown in Fig. 5, the coating layer 10 may have a layer structure in which a plurality of first coating layers 14 each having a color base layer 11, a primer layer 12 formed under the color base layer 11, and a clear layer 13 formed on the color base layer 11 are laminated. As shown in Fig. 5, the laminate structure 1 of the fifth embodiment has a laminate structure including a coating layer 10 in which a plurality of first coating layers 14 each having a color base layer 11, a primer layer 12, and a clear layer 13 are laminated, a substrate 20, and at least one negative dielectric material layer 30.

[0022] As shown in Fig. 6, the coating layer 10 may have a layer structure in which a plurality of second coating layers 15 each having a primer layer 12, a color base layer 11, and a clear layer 13 formed on the color base layer 11 are laminated. As shown in Fig. 6, the laminate structure 1 of the sixth embodiment has a laminate structure including a coating layer 10 in which a plurality of second coating layers 15 each having a primer layer 12, a color base layer 11, and a clear layer 13 are laminated, a substrate 20, and at least one negative dielectric material layer 30.

[0023] The structure of each layer constituting the coating layer 10 will be described below.

[0024] <Color Base Layer> The color base layer 11 is formed on the outer surface (painted surface) of the substrate 20 or the primer layer 12. The color base layer 11 contains a resin material, a solvent, and a pigment. In addition to these materials, the color base layer 11 may also contain an ultraviolet absorber, a radical trapping agent, etc., as necessary.

[0025] Known resin materials commonly used in the field of paints can be used as the resin material for the color base layer 11. Examples of resin materials that can be used include polyester resins, urethane resins, epoxy resins, melamine resins, alkyd resins, phenolic resins, and acrylic resins.

[0026] Known organic solvents or water-soluble solvents (such as water) commonly used in the coating field can be used as the solvent for the color base layer 11. Examples of organic solvents include hydrocarbons such as toluene and xylene, ketones such as acetone, methyl ketone and methyl ethyl ketone, esters such as ethyl acetate and butyl acetate, and alcohols.

[0027] The color base layer 11 contains a color pigment and / or a luster pigment. The pigment may be any of various color pigments used in paints, and may be either an organic or inorganic pigment. Alternatively, the luster pigment may contain a luster material that is non-spherical and approximately flat (e.g., flake-like, scale-like, plate-like, thin-plate-like, etc.) such as aluminum flakes, mica, or glass.

[0028] <Primer Layer> The primer layer 12 is formed on the outer surface (painted surface) of the substrate 20. The primer layer 12 is a layer for improving the adhesion between the color base layer 11 and the substrate 20.

[0029] For example, a known resin paint for primers can be used as the material for the primer layer 12. Examples of resin paints that can be used include modified polyolefin resins, polyester resins, urethane resins, epoxy resins, melamine resins, alkyd resins, phenolic resins, and acrylic resins. In addition to the resin material, the primer layer 12 may contain known additives as appropriate.

[0030] <Clear Layer> The clear layer 13 is formed on the outer surface (painted surface) of the color base layer 11. The clear layer 13 is a layer for imparting weather resistance, gloss, scratch resistance, and stain resistance to the laminated structure 1. The clear layer 13 can be made of a conventionally known transparent resin material (whether colored or colorless) that has the above properties. The clear layer 13 may also contain, for example, a fluororesin, and may contain weather resistance agents, plasticizers, stabilizers, fillers, dispersants, dyes, pigments, solvents, etc. as needed.

[0031] The coating layer 10 is formed by applying a color base layer 11, a primer layer 12, and a clear layer 13 one or more times.

[0032] The coating layer 10 is not limited to the laminated structure shown in Fig. 1 and may be appropriately modified depending on the application of the part. That is, the coating layer 10 may include other functional layers in addition to the color base layer 11, the primer layer 12, and the clear layer 13.

[0033] <Substrate> The substrate 20 is made of a material that is unlikely to adversely affect electromagnetic wave transmission and has excellent impact resistance and weather resistance, and the coating layer 10 is formed on the outer surface of the substrate 20.

[0034] Synthetic resin materials are suitable as constituent materials of the substrate 20, and examples thereof include various synthetic resin materials, including thermoplastic resins such as general-purpose plastics (polypropylene (PP), polyvinyl chloride (PVC), acrylic resin (PMMA), acrylonitrile butadiene styrene resin (ABS)), and engineering plastics (polycarbonate (PC)). These synthetic resin materials can be appropriately selected depending on the application of the laminated structure 1.

[0035] When a resin material is used for the substrate 20, taking into consideration the effect on the electromagnetic wave transmittance of the coating layer 10 in the laminated structure 1, it is preferable to use a material that does not contain metal or that contains a metal content to the extent that it does not adversely affect the electromagnetic wave transmittance.

[0036] The method for forming (applying) the coating layer 10 to the substrate 20 is not particularly limited, and examples thereof include known coating methods (e.g., dipping, spin coating, flow coating, roll coating, spray coating, blade coating, and air knife coating). The coating layer 10 can be formed by appropriately selecting one of these coating methods depending on the shape and application of the coated article 1, the composition of the coating layer 10 and the substrate 20, and the like. The drying step for the coating layer 10 can be performed by appropriately selecting one of natural drying, forced drying, and the like.

[0037] <Negative Dielectric Material Layer> At least one negative dielectric material layer 30 is disposed between the coating layer 10 and the substrate 20 and / or on a layer constituting the coating layer 10 .

[0038] At least one negative dielectric material layer 30 is disposed in a laminate structure formed on the outer surface side of the substrate 20, i.e., on the side opposite to the inner surface of the substrate 20 facing the radar device 100 in the layer structure shown in Figures 1 to 6. One or more negative dielectric material layers 30 can be formed at the positions indicated by the thick arrows in Figures 1 to 6.

[0039] In the laminated structure 1 according to this embodiment, the placement position of the negative dielectric material layer 30 is extremely important. In a vehicle component, a coating layer 10 is formed directly on the outer surface of a substrate 20. Therefore, when placing the negative dielectric material layer 30 on a vehicle component, it is common technical knowledge to place it between the radar device 100 and the substrate 20, on the side opposite the surface of the substrate 20 on which the coating layer 10 is formed, in consideration of design. When the negative dielectric material layer 30 is placed between the radar device 100 and the substrate 20, as in the prior art, the dielectric constant of only the substrate 20 in contact with the negative dielectric material layer 30 is neutralized, thereby reducing transmission attenuation to a certain extent. However, in the prior art, because the negative dielectric material layer 30 is in contact only with the substrate 20, there is a problem in that, for example, when a color base layer 11 containing a metallic pigment or the like is formed on the coating layer 10, transmission attenuation is not sufficiently reduced.

[0040] In order to solve the above-mentioned problems, the inventors of the present invention have conducted extensive research into optimizing the placement of the negative dielectric material layer 30. The inventors discovered that the negative dielectric material layer 30 can be placed on the surface of the substrate 20 opposite the radar device 100, with the substrate 20 having a relatively high dielectric constant sandwiched between them. As a result, the inventors discovered that by bringing the negative dielectric material layer 30 into contact with not only the substrate 20 but also each layer constituting the coating layer 10, the dielectric constant can be effectively neutralized and transmission attenuation can be reduced, leading to the development of the present invention. Furthermore, in the present invention, when the negative dielectric material layer 30 is formed on the outer surface of the substrate 20, advances in processing technology for the negative dielectric material layer 30, such as direct printing of a conductor, have made it possible to minimize the impact on design.

[0041] The negative dielectric material layer 30 is a functional layer produced based on metamaterial technology, and has at least a conductive pattern 31. The negative dielectric material layer 30 can be configured to have a support member 32 that supports the conductive pattern 31. When the negative dielectric material layer 30 has only the conductive pattern 31, it can be supported by being sandwiched between the coating layer 10 and the substrate 20 without having the support member 32.

[0042] 7A and 7B show examples of the negative dielectric material layer 30. As shown in FIG. 7A , the negative dielectric material layer 30 has a lattice-shaped conductive pattern 31 sandwiched between a pair of support members 32. In the configuration shown in FIG. 7A , the negative dielectric material layer 30 may be composed of only the conductive pattern 31. As shown in FIG. 7B , the negative dielectric material layer 30 may also employ a conductive pattern 31 in which rectangular ring-shaped elements are arranged in parallel vertically and horizontally at a predetermined interval. The negative dielectric material layer 30 is not limited to the configuration of only the conductive pattern 31 shown in FIG. 7B , and may be sandwiched between sandwiching members 32. Note that the conductive pattern 31 is not limited to the configuration shown in FIGS. 7A and 7B , and may be in any form that can at least function as the negative dielectric material layer 30, such as a form in which multiple linearly formed conductive patterns are arranged in parallel at a predetermined interval, or a form in which the conductive pattern 31 is formed in a plate shape and then circular or rectangular holes are formed at equal intervals (periodic punch holes).

[0043] The conductive pattern 31 is formed of a conductive material (whether organic or inorganic) such as a metal or a transparent conductor. Examples of the material of the conductive pattern 31 include metals such as copper, aluminum, nickel, and silver, conductive resins, and transparent conductors such as indium tin oxide (ITO).

[0044] The conductive pattern 31 can be obtained by forming a film on the target area by a known film formation method such as vapor deposition, sputtering, or chemical vapor deposition (CVD), and then patterning the film into a predetermined pattern by a known patterning method such as photolithography. Alternatively, the conductive pattern 31 may be formed by transferring a thin film patterned into a predetermined shape to the target area. Alternatively, the conductive pattern 31 can be formed by silk printing, gravure printing, offset printing, inkjet printing, printing using a 3D printer, or the like.

[0045] The support member 32 supports the conductive pattern 31. The support member 32 is disposed on one or both sides of the conductive pattern 31.

[0046] Considering ease of handling, the support member 32 is preferably a resin film, examples of which include organic resin films such as polyethylene film, polyolefin films such as polyvinyl chloride, polyethylene terephthalate (PET) film, polyethylene naphthalate film, polycarbonate film, polyimide film, etc. Note that the support member 32 is not limited to a resin film and may be in other forms.

[0047] The thickness of the support member 32 is not particularly limited and can be set appropriately depending on the constituent materials and layer structure of the substrate 20 and the coating film 10. As an example, the average thickness of the support member 32 is preferably 0 μm or more and 70 μm or less. Note that a thickness of "0 μm" for the support member 32 indicates a configuration in which the support member 32 is not used as a constituent part of the negative dielectric material layer 30, i.e., a configuration in which only the conductive pattern 31 is used. Furthermore, in the case where the conductive pattern 31 is sandwiched between the support members 32, for example, the thickness of the support member 32 is the total value of the two layers.

[0048] The support member 32 may be disposed with one or both sides sandwiched between resin films, or may be formed by impregnating the conductive pattern in the resin material described above.

[0049] As shown in FIGS. 1 to 6 , the negative dielectric material layer 30 can be arranged in contact with a single layer or multiple layers of the substrate 20, color base layer 11, primer layer 12, and clear layer 13 to neutralize the dielectric constant of the components in contact with the negative dielectric material layer 30. As a result, the laminate structure 1 can effectively reduce transmission attenuation. The dotted arrows in FIGS. 1 to 6 indicate positions where the negative dielectric material layer 30 can be arranged. One negative dielectric material layer 30 can be provided at the position indicated by the dotted arrow in FIGS. 1 to 6 , and at least one negative dielectric material layer 30 may be present in the laminate structure 1.

[0050] 5, one negative dielectric material layer 30 may be disposed for one first coating layer 14. When one negative dielectric material layer 30 is disposed for one first coating layer 14, the transmission attenuation can be reduced more effectively.

[0051] 6, one negative dielectric material layer 30 may be disposed for one second coating layer 15. When one negative dielectric material layer 30 is disposed for one second coating layer 15, the transmission attenuation can be reduced more effectively.

[0052] [Effects] As described above, the laminated structure 1 according to this embodiment is disposed in the direction of emission of electromagnetic waves from the radar device 100, which transmits and receives electromagnetic waves W to measure the physical quantity of a detection target, and has a laminated structure including a substrate 20 made of a resin material, and, on the opposite side of the radar device 100 across the substrate 20, at least one negative dielectric material layer 30 and a coating layer 10 including at least one color base layer 11 having a color pigment and / or a lustrous pigment.

[0053] With this configuration, the negative dielectric material layer 30 is disposed in contact with the substrate 20 and the color base layer 11, and can neutralize the dielectric constant of the members in contact with the negative dielectric material layer 30. Therefore, the laminated structure 1 can effectively reduce the transmission attenuation.

[0054] In addition, the coating layer 10 of this embodiment may include at least one primer layer 12 formed under the color base layer 11, and at least one negative dielectric material layer 30 may be arranged between the substrate 20 and the coating layer 10 and / or on a layer constituting the coating layer 10.

[0055] With this configuration, the negative dielectric material layer 30 is disposed in contact with any of the substrate 20, the color base layer 11, and the primer layer 12, and can neutralize the dielectric constant of the member in contact with the negative dielectric material layer 30. Therefore, the laminated structure 1 can effectively reduce the transmission attenuation.

[0056] In addition, the coating layer 10 according to this embodiment may include at least one clear layer 13 formed on the color base layer 11, and at least one negative dielectric layer 30 may be arranged between the substrate 20 and the coating layer 10 and / or on a layer constituting the coating layer 10.

[0057] With this configuration, the negative dielectric material layer 30 is disposed in contact with any of the substrate 20, the color base layer 11, and the clear layer 13, and can neutralize the dielectric constant of the member in contact with the negative dielectric material layer 30. Therefore, the laminated structure 1 can effectively reduce the transmission attenuation.

[0058] Furthermore, the coating layer 10 according to this embodiment may include at least one primer layer 12 formed under the color base layer 11 and at least one clear layer 13 formed on the color base layer 11, and at least one negative dielectric material layer 30 may be disposed between the substrate 20 and the coating layer 10 and / or on a layer constituting the coating layer 10.

[0059] With this configuration, the negative dielectric material layer 30 is disposed in contact with any of the substrate 20, the color base layer 11, the primer layer 12, and the clear layer 13, and can neutralize the dielectric constant of the member in contact with the negative dielectric material layer 30. Therefore, the laminated structure 1 can effectively reduce the transmission attenuation.

[0060] Furthermore, the coating layer 10 according to this embodiment includes a first coating layer 14 including a color base layer 11, a primer layer 12 formed under the color base layer 11, and a clear layer 13 formed on the color base layer 11, and the first coating layer 14 may be laminated in multiple layers on the substrate 20, and at least one negative dielectric material layer 30 may be arranged between the substrate 20 and the coating layer 10 and / or on a layer constituting the coating layer 10.

[0061] With this configuration, the negative dielectric material layer 30 is disposed in contact with any of the plurality of first coating layers 14 including the substrate 20, the color base layer 11, the primer layer 12, and the clear layer 13, and can neutralize the dielectric constant of the members in contact with the negative dielectric material layer 30. Therefore, the laminated structure 1 can effectively reduce transmission attenuation.

[0062] Furthermore, the negative dielectric material layer 30 according to this embodiment may be configured so that one layer is disposed for one first coating layer 14 .

[0063] With this configuration, the negative dielectric material layer 30 can be efficiently disposed on the first coating layer 14 and the substrate 20, so that the transmission attenuation can be reduced more effectively.

[0064] Furthermore, the coating layer 10 according to this embodiment includes a primer layer 12 formed on the substrate 20, and a second coating layer 15 including a color base layer 11 and a clear layer 13 formed on the color base layer 11, and the second coating layer 15 may be laminated in multiple layers on the primer layer 12, and at least one negative dielectric material layer 30 may be arranged between the substrate 20 and the coating layer 10 and / or on a layer constituting the coating layer 10.

[0065] With this configuration, the negative dielectric material layer 30 is disposed in contact with any of the plurality of second coating layers 15 including the substrate 20, the primer layer 12, the color base layer 11, and the clear layer 13, and therefore can neutralize the dielectric constant of the members in contact with the negative dielectric material layer 30. Therefore, the laminated structure 1 can effectively reduce transmission attenuation.

[0066] Furthermore, the negative dielectric material layer 30 according to this embodiment may be configured to be disposed one for one second coating layer 15 .

[0067] With this configuration, the negative dielectric material layer 30 can be efficiently disposed on the second coating layer 15 and the substrate 20, so that the transmission attenuation can be reduced more effectively.

[0068] The following embodiments are also included within the scope of the present invention: a laminate structure according to claim 1 having the features of claim 2; a laminate structure according to claim 1 having the features of claim 3; a laminate structure according to claim 1 having the features of claim 4; a laminate structure according to claim 1 or 4 having the features of claim 5; a laminate structure according to claim 5 having the features of claim 6; a laminate structure according to claim 1 or 4 having the features of claim 7; and a laminate structure according to claim 7 having the features of claim 8.

[0069] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to the following examples.

[0070] Examples and comparative examples of the laminated structure according to the embodiment of the present invention will be described.

[0071] [Evaluation Test] In the evaluation test, the "thickness," "dielectric constant (F / m, ε)," and "magnetic permeability (H / m, μ)" of the substrate, primer layer, color base layer, clear layer, and negative dielectric material layer shown below were simulated using the engineering calculation software "PTC Mathcad Prime 8 (manufactured by PTC Japan Co., Ltd.)" to simulate the attenuation characteristics (simulation of the transmission attenuation of 76.5 GHz electromagnetic waves). The negative dielectric material layer was a metal grid made of copper foil with a grid line width of 0.2 mm, a grid line spacing of 2.0 mm, a grid thickness of 0.035 mm, and a grid line width of 0.2 mm, with a 0.035 mm thick polyamide resin film sandwiched between them. In this evaluation test, the "grating line width" was the length indicated by "w" in FIG. 7A, the "grating line spacing" was the length indicated by "a" in FIG. 7A, and the "grating thickness" was the length indicated by "d" in FIG. 7A. <Base material> Resin type: polypropylene resin, pigment type: carbon black, pigment / resin ratio: trace amount, thickness: 2.5 mm, dielectric constant: 2.57-0.0028j, magnetic permeability: 1.0 <Primer layer> Resin type: epoxy resin, pigment type: conductive titanium oxide, talc, pigment / resin ratio: 100%, thickness: 6.0 μm, dielectric constant: 8.13-1.21j, magnetic permeability: 1.0 <Color base layer> Resin type: acrylic resin, polyester resin, urethane resin, melamine resin, pigment type: aluminum powder, pigment / resin ratio: 15%, thickness: 25 μm, dielectric constant: 22.11-0.02j, magnetic permeability: 1.0 <Clear layer> Resin type: acrylic resin, pigment type: none, pigment / resin ratio: none, thickness: 33 μm, dielectric constant: 3.49-0.03j, magnetic permeability: 1.0 <Negative dielectric material layer> Thickness: 105 μm, dielectric constant: -4.33 (for electromagnetic waves of 76.5 GHz), magnetic permeability: 1.0.

[0072] [Evaluation Results] Figures 8 to 13 show the evaluation results for Examples 1 to 6, the Reference, and the Comparative Example. The evaluation results were marked with "Good" if the attenuation exceeded the evaluation standard set for each of Examples 1 to 6, and marked with "Poor" if the attenuation fell short. The evaluation standard for each Example was determined based on the attenuation required for the radar device to function normally in the layer structure of the laminated structure of each Example. The bold lines in each layer structure shown in Figures 8 to 13(a) indicate the location of the negative dielectric layer. The laminate structure of the Reference sample did not include a negative dielectric layer, while the laminate structure of the Comparative Example sample, like the prior art, had a negative dielectric layer disposed on the surface of the substrate facing the radar device.

[0073] Example 1 Figure 8(a) shows the laminated structures of Samples A1 and A2 according to Example 1, as well as the Comparative Example and Reference Samples, and Figure 8(b) shows the attenuation and evaluation results for each sample. Both Samples A1 and A2 have a configuration in which a negative dielectric material layer is disposed on the opposite side of the radar device, sandwiching a substrate therebetween, and the attenuation met the evaluation standard (attenuation > -2.0 dB). In contrast, the Comparative Example had an attenuation of -0.21 dB, which was below the evaluation standard. From these results, it was confirmed that "disposing a negative dielectric material layer on the opposite side of the radar device, sandwiching a substrate therebetween," can neutralize the dielectric constant through contact between the substrate or coating layer and the negative dielectric material layer, effectively reducing transmission attenuation.

[0074] Example 2 Figure 9(a) shows the laminate structures of Samples B1 to B3 according to Example 2, the Comparative Example, and the Reference Sample, and Figure 9(b) shows the attenuation and evaluation results for each sample. Samples B1 to B3 all had a configuration in which a negative dielectric material layer was disposed on the opposite side of the radar device across the substrate, and the attenuation met the evaluation standard (attenuation > -0.3 dB). In contrast, the Comparative Example had an attenuation of -0.33 dB, which was below the evaluation standard. These results confirmed that "disposing a negative dielectric material layer on the opposite side of the radar device across the substrate" and "disposing a negative dielectric material layer between and / or on layers in a laminate structure consisting of a substrate, a primer layer, and a color base layer" can neutralize the dielectric constant through contact between the substrate or coating layer and the negative dielectric material layer, effectively reducing transmission attenuation.

[0075] Example 3 Figure 10(a) shows the laminated structures of Samples C1 to C3 according to Example 3, the Comparative Example, and the Reference Sample, and Figure 10(b) shows the attenuation and evaluation results for each sample. Samples C1 to C3 all had a configuration in which a negative dielectric layer was placed on the opposite side of the radar device across the substrate, and the attenuation met the evaluation standard (attenuation > -0.3 dB). In contrast, the Comparative Example had an attenuation of -0.34 dB, which was below the evaluation standard. These results confirmed that "placing a negative dielectric layer on the opposite side of the radar device across the substrate" and "placing a negative dielectric layer between and / or on layers in a laminated structure consisting of a substrate, a color base layer, and a clear layer" can neutralize the dielectric constant through contact between the substrate or coating layer and the negative dielectric layer, effectively reducing transmission attenuation.

[0076] Example 4 Figure 11(a) shows the laminate structures of Samples D1 to D4 according to Example 4, the Comparative Example, and the Reference Sample, and Figure 11(b) shows the attenuation and evaluation results for each sample. All of Samples D1 to D4 had a configuration in which a negative dielectric material layer was placed on the opposite side of the radar device across the substrate, and the attenuation met the evaluation standard (attenuation > -0.4 dB). In contrast, the Comparative Example had an attenuation of -0.47 dB, which was below the evaluation standard. These results confirmed that "placing a negative dielectric material layer on the opposite side of the radar device across the substrate" and "placing a negative dielectric material layer between and / or on layers in a laminate structure consisting of a substrate, a primer layer, a color base layer, and a clear layer" can neutralize the dielectric constant through contact between the substrate or coating layer and the negative dielectric material layer, effectively reducing transmission attenuation.

[0077] Example 5 Figure 12(a) shows the laminate structures of Samples E1 to E21 according to Example 5, the Comparative Example, and the Reference Sample, and Figure 12(b) shows the attenuation and evaluation results for each sample. All of Samples E1 to E21 had a configuration in which a negative dielectric material layer was disposed on the opposite side of the radar device across the substrate, and the attenuation met the evaluation standard (attenuation > -2.5 dB). In contrast, the Comparative Example had an attenuation of -2.51 dB, which was below the evaluation standard. These results confirmed that "disposing a negative dielectric material layer on the opposite side of the radar device across the substrate" and "disposing a negative dielectric material layer between and / or on a layer in a laminate structure having a substrate and multiple first coating layers composed of a primer layer, a color base layer, and a clear layer" can neutralize the dielectric constant through contact between the substrate or coating layer and the negative dielectric material layer, effectively reducing transmission attenuation.

[0078] In addition, in samples E1 to E21 of Example 5, from the viewpoint of transmission attenuation, when the evaluation standard (-2.5 dB) is used as a reference, it is preferable that the value exceeds -2.0 dB, and more preferably exceeds -1.50. In view of the above, it can be said that, in samples E1 to E21 of Example 5, from the viewpoint of transmission attenuation, configurations where dB>-1.50 (samples E3 to E5, samples E9 to E21) are suitable.

[0079] Example 6 Figure 13(a) shows the laminate structures of Samples F1 to F18 according to Example 6, the Comparative Example, and the Reference Sample, and Figure 13(b) shows the attenuation and evaluation results for each sample. All of Samples F1 to F18 had a configuration in which a negative dielectric material layer was disposed on the opposite side of the radar device across the substrate, and the attenuation met the evaluation standard (attenuation > -2.3 dB). In contrast, the Comparative Example had an attenuation of -2.33 dB, which was below the evaluation standard. These results confirmed that "disposing a negative dielectric material layer on the opposite side of the radar device across the substrate" and "disposing a negative dielectric material layer between and / or on a layer of a laminate structure having a plurality of second coating layers composed of a substrate, a primer layer, a color base layer, and a clear layer" can neutralize the dielectric constant through contact between the substrate or coating layer and the negative dielectric material layer, thereby effectively reducing transmission attenuation.

[0080] In addition, in samples F1 to F18 of Example 6, from the viewpoint of transmission attenuation, when the evaluation standard (-2.3 dB) is used as a reference, it is preferable that the value exceeds -2.0 dB, and more preferably exceeds -1.50. In view of the above, it can be said that, in samples F1 to F18 of Example 6, from the viewpoint of transmission attenuation, configurations where dB>-1.50 (samples F3, F4, F7 to F15, F17, and F18) are suitable.

[0081] REFERENCE SIGNS LIST 1 laminated structure, 10 coating layer, 11 color base layer, 12 primer layer, 13 clear layer, 20 substrate, 30 negative dielectric material layer, 31 conductive pattern, 32 support member, 100 radar device W electromagnetic wave.

Claims

1. A laminated structure interposed in the direction of electromagnetic wave emission of a radar device that transmits and receives electromagnetic waves to measure physical quantities with respect to an object to be detected, The laminated structure comprises a substrate made of a resin material, and a coating layer on the side opposite the radar device with the substrate in between, which includes at least one negative dielectric material layer and at least one color base layer having a coloring pigment and / or a luminous pigment. The negative dielectric layer is arranged on at least the layers constituting the coating layer in a laminated structure.

2. The aforementioned coating layer includes at least one primer layer formed beneath the color base layer. The laminated structure according to claim 1, wherein at least one negative dielectric layer is disposed between the substrate and the coating layer and / or on the layers constituting the coating layer.

3. The aforementioned coating layer includes at least one clear layer formed on the color base layer, The laminated structure according to claim 1, wherein at least one negative dielectric layer is disposed between the substrate and the coating layer and / or on the layers constituting the coating layer.

4. The aforementioned coating layer includes at least one primer layer formed beneath the color base layer and at least one clear layer formed on top of the color base layer. The laminated structure according to claim 1, wherein at least one negative dielectric layer is disposed between the substrate and the coating layer and / or on the layers constituting the coating layer.

5. The aforementioned coating layer includes a first coating layer comprising the color base layer, a primer layer formed beneath the color base layer, and a clear layer formed on top of the color base layer. Multiple layers of the first coating film are laminated on the substrate, The laminated structure according to claim 1, wherein at least one negative dielectric layer is disposed between the substrate and the coating layer and / or on the layers constituting the coating layer.

6. The laminated structure according to claim 5, wherein one negative dielectric layer is provided for each of the first coating layers.

7. The aforementioned coating layer includes a primer layer formed on the substrate, and a second coating layer which includes the color base layer and a clear layer formed on the color base layer. Multiple layers of the second coating film are laminated on the primer layer, The laminated structure according to claim 1, wherein at least one negative dielectric layer is disposed between the substrate and the coating layer and / or on the layers constituting the coating layer.

8. The laminated structure according to claim 7, wherein one negative dielectric material layer is provided for each second coating layer.

9. (delete)

10. The laminated structure according to claim 1, wherein the laminated structure has a layer structure in which the transmission attenuation of the electromagnetic wave exceeds -1.50 dB.

11. The laminated structure according to any one of claims 1 to 8 and 10, wherein the negative dielectric layer is not disposed between the substrate and the coating layer.

12. The laminated structure according to any one of claims 1 to 8 and 10, wherein the negative dielectric layer is disposed between the layers constituting the coating layer.

13. A laminated structure interposed in the direction of electromagnetic wave emission of a radar device that transmits and receives electromagnetic waves to measure physical quantities with respect to an object to be detected, The laminated structure comprises a substrate made of a resin material, and a coating layer on the side opposite the radar device with the substrate in between, which includes at least one negative dielectric material layer and at least one color base layer having a coloring pigment and / or a luminous pigment. The negative dielectric layer is a laminated structure comprising a conductive pattern and a support member that supports at least one surface of the conductive pattern.