Vehicle parts, sensor devices, automobiles, and methods and film sets for improving the transmittance of vehicle parts
Patent Information
- Application Number
- JP2025503379
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-07-25
- Filing Date
- 2023-07-12
- Publication Date
- 2026-02-06
AI Technical Summary
Existing vehicle parts, particularly those made of polymeric materials, have low reflectivity and absorption rates for radar waves, leading to interference with radar wave transmission and reception, which affects the performance of radar sensors and can saturate the signal, especially when painted with effect pigments.
A vehicle part is designed with a support part made of polymer material and coated on both sides with coatings having specific reflectivities, forming a resonator to minimize interference by adapting the reflectivity of the second coating to match the first, thereby enhancing transmittance of radar waves.
The vehicle part achieves a transmittance of over 50%, preferably over 80%, in the radar frequency range of 60-100 GHz, significantly reducing reflectivity and improving the signal-to-noise ratio of radar sensors, ensuring reliable operation.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a vehicle part having a support part; a sensor device including a vehicle chassis, at least one transmitter and detector arranged on the vehicle chassis, and a vehicle part attached to the area of the transmitter and / or detector; a motor vehicle having at least one radar distance sensor; and a method and film set for improving the transmittance of electromagnetic waves of a specific frequency, in particular radar waves.
Background Art
[0002] German Published Patent No. 10 2009 029 763 A1 discloses a plastic body component for a motor vehicle having a support with a plastic base body. The base body can be coated with a paint, in particular at least two layers of effect paint. With respect to radiation in the radar frequency range between 75 GHz and 85 GHz, the plastic body component has an attenuation with an absolute value of less than 3 dB in a single pass, at least in the radar transmission section.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] An object of the present invention is to explain an alternative, preferably particularly simply constructed vehicle part, sensor device, and method for manufacturing the same, which enables electromagnetic waves of a specific frequency, in particular radar waves, to be transmitted through the vehicle part with as little loss as possible.
Means for Solving the Problems
[0005] According to a first aspect of the present disclosure, a vehicle part is described. The vehicle part includes a support part made of a polymer material and having a first surface and a second surface substantially parallel thereto, a first coating applied to the first surface of the support part and having a first reflectivity R1 with respect to electromagnetic waves in a specific frequency spectrum, specifically radar waves, a second coating applied to at least one section of the second surface of the support part and having a second reflectivity R2 with respect to electromagnetic waves in a specific frequency spectrum, and the second reflectivity R2 is adapted to the first reflectivity R1, and the support part, the first coating, and the second coating are configured to form a resonator with respect to electromagnetic waves.
[0006] Here, the first coating can be a paint layer or a painted or colored plastic film. The plastic film can be colored with, for example, effect pigments. The film is usually self-adhesive and is simply adhesively bonded to the corresponding vehicle part.
[0007] In particular, the inventor has recognized that by applying an additional reflective layer to the second surface of the vehicle part, specifically to the rear surface of a support part whose front surface is coated or film-coated, such as a bumper, it is possible to form a resonator with respect to electromagnetic waves, specifically radar waves, thereby increasing the transmittance or decreasing the reflectivity of the vehicle part with respect to electromagnetic waves in a specific frequency spectrum or in a range near a predetermined operating frequency or center frequency. For this purpose, for example, with respect to a predetermined operating frequency or center frequency, or the entire frequency spectrum, the reflectivity R2 of the coating on the second surface is adapted to the reflectivity R1 of the first coating on the first surface.
[0008] In at least one embodiment, the vehicle part has a transmittance of more than 50%, preferably more than 80%, in a frequency spectrum between, for example, 60 and 100 GHz, in particular between 75 and 85 GHz. This frequency spectrum is used in particular for radar-based collision avoidance radars and / or adaptive cruise controllers.
[0009] In at least one embodiment, the support part can be manufactured from a plastic material and can have a thickness in the range from 1.5 to 5 mm. The thickness of such a material achieves the rigidity required for the vehicle structure and at the same time is approximately the size of the wavelength of the radar wave.
[0010] In at least one embodiment, the first coating comprises an effect coating layer containing an effect pigment having a thickness, for example, between 12 and 20 μm. Together with other coating layers, for example an underlying primer and base coat, and an upper clear coat, the first coating can have a total thickness in the range between 80 and 130 μm. Such coating layers and thicknesses have a reflectivity that achieves the desired appearance for the vehicle structure and enables the configuration of the resonator.
[0011] In at least one embodiment, the second coating has a structure similar to that of the first coating. For example, applying the same paint to the second surface of the vehicle part with the same thickness, applying the paint to the rear part is a particularly simple way to ensure that the two coatings are of equal quality.
[0012] In at least one alternative embodiment, the second coating has a thin metallized plastic film or metal foil adhesively bonded to the rear side of the vehicle part. This type of vehicle part can be manufactured particularly simply and at low cost by adhering film sections having the required reflectivity. In this case, preferably using a self-adhesive film makes it possible to easily incorporate it into an existing vehicle part, for example, after determining the reflectivity of the existing paint finish on the first surface.
[0013] This type of vehicle part is, in particular, suitable for manufacturing a sensor device, and includes at least one transmitter for transmitting electromagnetic waves of a specific frequency, in particular radar waves, and at least one arranged detector for detecting electromagnetic waves of a specific frequency, in particular reflected radar waves, which are arranged on the vehicle chassis and covered by the vehicle part.
[0014] This type of vehicle part or this type of sensor device is, in particular, suitable for use in a motor vehicle equipped with a radar sensor.
[0015] According to another aspect of the present disclosure, a method for improving the transmittance of a vehicle part with respect to electromagnetic waves of a specific frequency, in particular radar waves, is disclosed. The method includes determining the reflectance of a first coating on a first surface of the vehicle part, in particular the reflectance of a paint layer applied to the outside of the vehicle part, and applying a second coating to at least one section of a second surface of the vehicle part opposite to the first surface, wherein the reflectance of the second coating is adapted to the reflectance of the first coating.
[0016] According to another aspect of the present disclosure, a film set for improving the transmittance with respect to electromagnetic waves of a specific frequency, in particular radar waves, is disclosed. The film set includes a plurality of self-adhesive sections of metal foil or metallized plastic film, and the sections are different with respect to their reflectance and optionally with respect to their thickness. This type of film set makes it possible to manufacture the above-mentioned types of vehicle parts or sensor devices in a simple manner, in particular by selecting film sections having appropriate physical properties.
[0017] Further embodiments and advantages of the disclosed invention are disclosed in the following description of exemplary embodiments and the appended claims.
[0018] The present invention will be described in detail below based on various exemplary embodiments with reference to the drawings.
Brief Description of the Drawings
[0019]
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DETAILED DESCRIPTION OF THE INVENTION
[0020] The vehicle parts described below are particularly suitable for covering radar sensors. For example, radar distance sensors are increasingly being installed in motor vehicles to prevent accidents, improve driving comfort, and ultimately enable autonomous vehicles. Other applications are also possible, such as radar sensors for detecting seeds or liquids in commercial vehicles such as large trucks or agricultural machinery. In order to protect the radar wave transmitter and detector required for this from the influence of the environment and / or so as not to adversely affect the design of the vehicle front section from an aerodynamic or aesthetic point of view, the radar sensor is usually arranged behind a vehicle part or cover made of a polymeric material, such as a bumper in the form of an integral bumper of a motor vehicle or a fairing of a commercial vehicle.
[0021] The polymeric materials used for the production of such vehicle parts only have a relatively low reflectivity and a low absorption rate with respect to radar waves. However, for aesthetic reasons, such vehicle parts usually comprise a paint layer, or a painted preferably self-adhesive plastic film, or an already colored preferably self-adhesive plastic film, which match the paint finish of the other parts of the vehicle. Such plastic films or paint layers, in particular those containing metallic effect pigments, have a relatively high reflectivity and thus interfere with the emission of radar waves and the reception of the reflected radar waves.
[0022] FIG. 1 shows a schematic cross-section of a sensor device 4 of a motor vehicle (not shown otherwise), in particular a passenger car or a large truck.
[0023] The sensor device 1 includes a part of the vehicle chassis 2, a radar sensor in the form of a distance sensor 3, and a vehicle component 4 that covers the distance sensor 3. For example, a part of the chassis 2 is a vehicle front section made of a metal material. In the exemplary embodiment described, the vehicle component 4 is a bumper in the form of an integrated bumper substantially made of a polymer material, specifically a plastic material. Alternatively, the vehicle component 4 can also be a pure cover component for the radar sensor. Such a cover is also called a radome.
[0024] The distance sensor 3 includes a transmitter 3a for emitting electromagnetic waves 5 in a specific frequency spectrum. In this case, the frequency spectrum is a continuous frequency range, for example, a frequency range between a maximum frequency and a minimum frequency, or a range having a predetermined bandwidth centered around a predetermined frequency. Specifically, the transmitter 3a emits radar waves 5a in a frequency spectrum between 70 and 80 GHz. Such electromagnetic radar waves 5a are reflected by a vehicle traveling ahead or other obstacles and transmitted as reflected electromagnetic radar waves 5b back to the detector 3b of the distance sensor 3. In this process, the electromagnetic waves 5 pass through the vehicle component 4 twice. However, in a further embodiment, the transmitter and the detector can also be one and the same component.
[0025] The vehicle component 4 usually has a complex rounded shape, but at least in the region where the radar waves 5a or 5b pass through the vehicle component 4, it has surfaces that are substantially parallel to each other. When the outer surface of the vehicle component 4 on the right side of FIG. 1 is painted with an effect paint or adhesively bonded to a film containing an effect pigment, a significant proportion of the emitted radar waves 5a and the reflected radar waves 5b are reflected by the vehicle component 4, and the signal-to-noise ratio of the distance sensor 3 decreases significantly. In particular, the part of the emitted radar waves that is reflected inwards can interfere with the sensor or even bring it into a completely saturated state.
[0026] FIG. 2 shows an enlarged view of the details of the vehicle component 4 according to FIG. 1. It should be noted that FIG. 2 is for illustrative purposes only and does not reflect the actual size ratio of the vehicle component 4.
[0027] The vehicle part 4 according to FIG. 2 has a support part 6 with two mutually parallel surfaces 7 and 8. In the illustrated exemplary embodiment, the right surface 7 in FIG. 2 faces outward from a distance sensor 3 (not shown in FIG. 2), and the opposite second surface 8 faces the distance sensor 3. Thus, the first surface 7 is typically on the outside of the vehicle part 4, and the second surface 8 is typically on the inside of the vehicle part 4.
[0028] The first coating 9 is disposed on the first surface 7. This is, for example, a coating layer or film 12 containing many effect pigments 13. Specifically, the effect pigments 13 ensure a beautiful effect of the coating layer 12 (for example, metallic effect, brilliance and / or color flop, and in some cases shine). The effect pigments 13 are, for example, metallic effect pigments in the form of fine aluminum flakes with a thickness of less than 1 μm. Such aluminum flakes can be produced, for example, by flattening small aluminum beads and stirring them into a suitable carrier paint. In addition to metallic effect pigments, non-metallic effect pigments are also known. Such effect pigments are based on flaky substrates, such as natural or synthetic mica, talc, SiO2 flakes, Al2O3 flakes, glass flakes, iron oxide flakes, graphite flakes, which are completely coated with one or more metal oxides. Similarly, a conductive primer that reflects an additional portion of electromagnetic radiation is often used for the coating film 12. Without further measures, the coating 12, specifically the effect pigments 13 and the primer contained therein, significantly increase the reflectivity of the first coating 9. Thus, a significant proportion of the electromagnetic waves 5 impinging on the vehicle part 4 will be reflected.
[0029] To reduce or completely prevent this effect, a second coating 10 is disposed on the second surface 8. In an exemplary embodiment, the second layer 10 is, for example, an adhesively bonded film, in particular a self-adhesive metal foil or a metallized plastic film 14. When a metallized plastic film 14 is used, controlling its thickness can further result in a controlled shift of the resonant frequency.
[0030] 2, the second coating 10 does not necessarily have to cover the entire second surface 8 of the vehicle component 4. It is sufficient that the second coating 10 is arranged at least on a section 15 of the second surface 8 that is transparent to the electromagnetic waves 5, i.e., for example, on the area of the vehicle component 4 behind which the distance sensor 3 is arranged. Alternatively, the second coating 10 can cover the entire second surface 8.
[0031] The reflectivity of the second coating 10 is closely matched to the reflectivity of the first coating 9. Thus, the first coating 9, the support 6, and the second coating 10 together form a resonator 11. By matching the dimensions of the resonator 11 to the frequency of the electromagnetic wave 5, the resonator 11 as a whole has a reflectivity that is significantly reduced compared to the reflectivities of the individual layers 9 and 14. This means that the electromagnetic wave 5 can pass through the vehicle component 4 substantially unattenuated. In other words, the vehicle component 4 is largely transparent to the electromagnetic wave 5 within the resonance range.
[0032] In an exemplary embodiment, the support 6 is made of a polymer material and has a thickness D of, for example, 2 to 3 mm. The first layer 9 and second coating 10 have a thickness of approximately 20 μm and a reflectivity of approximately 10 to 20 percent for frequencies of 70 to 80 GHz, which are typical for radar-based distance sensors. This corresponds to a wavelength in air of approximately 4.28 to 3.75 mm. Therefore, the thickness D of the support 6, which is approximately 2 mm, corresponds to approximately half the wavelength of the electromagnetic wave 5.
[0033] The resonator 11 basically corresponds to a relatively weak Fabry - Perot interferometer having, for example, a quality of a resonator of less than 100, particularly less than 20, for example 15 or 10. Here, for the quality Q of the resonator at the resonance frequency f0 and the bandwidth Δf, the following formula, Q = f0 / Δf is applicable.
[0034] The maximum value of the transmittance is a multiple of half of the half - wavelength λ D = m / n·λ / 2 is obtained. Here, n is the refractive index of the material used, and m is a positive natural number.
[0035] The transmittance T of the Fabry - Perot interferometer depends particularly on the first reflectance R1 of the first coating 9 and the second reflectance R2 of the second coating 10. Ignoring absorption losses, for the maximum transmittance of the resonator in the case of resonance, the following formula, Tmax = ((1 - R1)(1 - R2) / (1 - √R1·R2)) 2 is applicable.
[0036] Above and below the resonance frequency, the transmittance T decreases accordingly. When both surfaces 7, 8 of the support part 6 have the same reflectance with respect to the electromagnetic wave 5 used by the distance sensor 3, that is, when R1 = R2, a theoretical maximum transmittance T of 100% is obtained. Realistically, the actual transmittance T is further reduced by, for example, absorption losses of the polymer material of the support part 6 and other components of the coatings 9 and 10. However, in practice, these losses are small enough not to significantly impair the function of the distance sensor 3.
[0037] One possibility for matching the reflectivities R1 and R2 of the coatings 9 and 10 to each other is to first determine the reflectivity R1 of the coating 12. For this purpose, first, the vehicle part 4 already painted on one side can be measured. Then, a film with a reflectivity R2 closest to the reflectivity R1 of the first coating 9 can be selected, for example, from metallized plastic films 14 of arbitrarily different thicknesses. By selecting the thickness, it is possible to achieve a shift that may be desirable within the resonance range, if desired. The selected film 14 is then adhesively bonded to the back surface 8 of the support 6.
[0038] For this purpose, for example, a film set including a plurality of film sections having different physical properties can be used. For example, each film section can be arranged and marked in a matrix, where the film sections in the columns have different reflectivities and the same thickness, and the film sections in the rows have the same reflectivity and different thicknesses.
[0039] Another possibility for matching the reflectivities R1, R2 of the coatings 9, 10 to each other is to provide equivalent coating layers on both sides of the support 6. Similar to the above, the coating can be performed only in the region 15 of the sensor 3 or over the entire surface.
[0040] To confirm the above effects, a total of five samples were manufactured. The structures of four of the five samples are shown in FIGS. 3A to 4B.
[0041] Sample 0F0R is composed of a plastic sheet not shown and is not coated on both sides. Specifically, a 3 mm thick sheet made of polycarbonate under the trade name Makrolon (registered trademark) has electromagnetic properties similar to the plastic used for, for example, bumpers.
[0042] Sample 2F0R according to FIG. 3A has, on the first surface 7, a single coating layer 12 with a thickness of approximately 13 μm on only one side. Such a thickness is typical for painted automotive parts 4. The paint used contains a mass concentration of approximately 18% of aluminum pigment in the solid paint (18% PMC aluminum effect pigment), which corresponds to a very high pigmentation of automotive metallic paints. This sample is used, in particular, to demonstrate the reflection / transmission behavior of conventional vehicle parts 4 painted on only one side.
[0043] Sample 2F2R according to FIG. 3B is coated on both sides with a single coating layer 12 approximately 13 μm thick. For this reason, both surfaces 7 and 8 of the support 6 are coated with the same vehicle paint containing the metallic effect pigment 13.
[0044] FIGS. 4A and 4B show two further samples 4F0R and 4F4R, the surfaces 7 and 8 of which are provided with a double coating layer 12 with a total thickness of approximately 27 μm. In the case of sample 4F0R according to FIG. 4A, only the first surface 7 is painted, while in the case of sample 4F4R according to FIG. 4B, the first surface 7 and the second surface 8 are painted in the same way.
[0045] As a first example, FIGS. 5A and 5B show the transmission / reflection behavior of an unpainted plastic sheet according to sample 0F0R and a plastic sheet 2F0R painted on one side according to FIG. 3A, as a percentage and the corresponding signal attenuation (decibels). As can be seen in particular from FIG. 5A, the uncoated plastic material has a reflectivity of 0 to 20 percent and a transmittance of approximately 75 to 95 percent in the relevant frequency spectrum between 60 and 90 GHz. Here, the lowest reflectivity is in the frequency spectrum below 65 GHz, which is not normally used by radar sensors. Values less than 100% can be explained in detail by absorption by the plastic material.
[0046] As shown in Fig. 3A, by applying a single coating layer 12, the minimum value of the reflectivity shifts to approximately 83 GHz. In contrast, there is a maximum value in the range between 64 and 77 GHz, the reflectivity is approximately 30 to 40%, while the transmittance decreases to approximately 55 to 65%.
[0047] In Figs. 6A and 6B, the measured transmittance / reflectivity values of two samples 2F0R and 2F2R according to Figs. 3A and 3B are compared. As can be seen from Figs. 6A and 6B, the transmittance is greater than 85% maximum near the frequency of 77 GHz. Therefore, the reflectivity at this frequency is a minimum of approximately 0 percent (-24 dB). As a result, the vehicle part 4 does not substantially cause interfering reflections in the typical frequency spectrum of a radar sensor. In addition, the transmitted signal component increases significantly and the signal-to-noise ratio is significantly improved.
[0048] In Fig. 6A, in particular, it can be seen that there is a continuous frequency range where the reflectivity of the double-painted sample 2F2R is significantly lower than the minimum value of the reflectivity of the single painted sample 2F0R. Similarly, the transmittance is significantly greater in this range. In the hatched range between 74 GHz and 79 GHz, the radar type distance sensor can be operated in a reliable manner.
[0049] In Figs. 7A and 7B, the measurement results of samples 4F0R and 4F4R according to Figs. 4A and 4B are correspondingly shown. As can be seen here, the maximum value of the transmittance / minimum value of the reflectivity has shifted in the direction of lower operating frequencies, specifically to the region of 72 GHz, by doubling the coating layer 12. Despite the significant increase in the reflectivity of the double-sided coating layer, the minimum value of the reflectivity in the range near 72 GHz is only a few percent, and thus it is similarly suitable for the radar type distance sensor 3. Furthermore, at approximately -14 dB, the reflected signal component of the double-painted sample 4F4R is approximately 10 dB lower than that of the sample 4F0R painted on only one side (the reflected signal component is approximately -4 dB).
[0050] Figs. 6A to 7B, when viewed together, show that by adapting the thickness of the coating layer 12, the resonance frequency of the vehicle part 4 can be adapted to the frequency of the electromagnetic waves 5 used, in particular the radar waves 5a and 5b. The thickness D of the support part 6 can be used as a further optimization parameter.
[0051] The reflectivity / transmittance of the coated vehicle part 4 can be further optimized when the reflectivity R2 of the selected second coating 10 is slightly smaller than the reflectivity R1 of the first coating 9 in order to at least partially compensate for the absorption by the support part 6. For example, the reflectivity R2 of the second coating 10 is about 80 to 99%, preferably 90 to 98%, for example 95% of the reflectivity R1 of the first coating 9.
[0052] Fig. 8 schematically shows the steps of a method for improving the transmittance of the vehicle part 4.
[0053] As shown in Fig. 8, in a first step S1, first the reflectivity R1 of the first coating 9 is determined.
[0054] As described above, this can be done by measuring the vehicle part 4 which is already coated on one side or based on the relevant parameters used in the manufacturing, in particular the transmittance, reflectivity, and absorption behavior of the materials used, the thickness of the support part 6, and the thickness of the first coating 9. In this case, the reflectivity R1 of the vehicle part 4 can be determined based on the corresponding theoretical model or a known series of measurements. Finally, it is also possible to obtain only the parameters used for the coating without explicitly obtaining the first reflectivity R1.
[0055] In a further step S2, the second coating 10 is applied to the opposite surface 8 and the reflectivity R2 of the second coating 10 is selected to substantially correspond to the first reflectivity R1.
[0056] As described above, this can be done by adhesively bonding the corresponding film section, specifically the self - adhesive metallized plastic film 14, to the second surface 8, or by painting at least one section 15 of the second surface 8. When substantially the same parameters such as the layer thickness of the coating layer are selected for the coating, in practice, since the reflection patterns of such coating layers 12 are almost identical, an explicit determination of the reflectivity can be omitted.
Explanation of Signs
[0057] 1 Sensor device 2 Chassis 3 Distance sensor 3a Transmitter 3b Detector 4 Vehicle part 5 Electromagnetic wave 5a (Emitted) radar wave 5b (Reflected) radar wave 6 Support part 7 First surface 8 Second surface 9 First coating 10 Second coating 11 Resonator 12 Coating layer 13 Effect pigment 14 Metallized plastic film 15 Cross - section (of the second surface 8) S1, S2 Method steps D Thickness of the support part
Claims
1. a support (6) made of a polymeric material and having a first surface (7) and a second surface (8) substantially parallel to said first surface (7); a first coating (9) applied to the first surface (7) of the support (6) and having a first reflectivity R1 with respect to electromagnetic waves (5) of a specific frequency spectrum, in particular radar waves (5a, 5b); a second coating (10) applied to at least one section (15) of the second surface (8) of the support (6), the second coating having a second reflectivity R2 with respect to electromagnetic waves (5) of the specific frequency spectrum; A vehicle component (4) comprising: The second reflectivity R2 is matched to the first reflectivity R1, and the support portion (6), the first coating (9), and the second coating (10) form a resonator (11) for the electromagnetic wave (5).
2. 2. The vehicle component (4) according to claim 1, wherein the first reflectivity R1 and the second reflectivity R2 differ from each other in terms of magnitude by at most 20 percent, preferably by less than 10 percent.
3. 2. The vehicle component (4) according to claim 1, wherein the specific frequency spectrum is in the range between 60 and 100 GHz, in particular in the range between 75 and 85 GHz.
4. 2. The vehicle component (4) according to claim 1, wherein the vehicle component (4) has a transmittance of more than 50%, preferably more than 80%, and / or a reflectance of less than 10%, preferably less than 5%, for the specific frequency spectrum.
5. 2. The vehicle component (4) according to claim 1, wherein the support (6) has a thickness (D) ranging between 1.5 and 5.0 mm, in particular ranging from 1.85 to 2.15 mm or from 3.70 to 4.3 mm.
6. 2. The vehicle part (4) according to claim 1, wherein the first coating (9) is a paint layer or a painted or pigmented plastic film.
7. 2. The vehicle component (4) according to claim 1, wherein the first coating (9) and / or the second coating (10) has a thickness ranging between 80 and 130 μm.
8. 2. The vehicle part (4) according to claim 1, wherein the first coating (9) comprises effect pigments (13), in particular metallic effect pigments.
9. 2. The vehicle component (4) of claim 1, wherein the second coating (10) has substantially the same structure, composition and thickness as the first coating (9).
10. 2. The vehicle component (4) of claim 1, wherein the second coating (10) comprises a metal foil or a metallized plastic film (14).
11. 2. The vehicle part (4) according to claim 1, wherein the vehicle part is configured as a bumper and / or a cover for a sensor device.
12. a vehicle chassis (2); at least one transmitter (3a) arranged on said vehicle chassis (2) for transmitting electromagnetic waves (5), in particular radar waves (5a), of a specific frequency spectrum; at least one detector (3b) arranged on the vehicle chassis (2) for detecting electromagnetic waves (5) of said specific frequency spectrum, in particular reflected radar waves (5b); a vehicle component (4) according to any one of claims 1 to 11, attached in the region of the transmitter (3a) and / or the detector (3b); A sensor device (1) comprising:
13. 12. A motor vehicle having at least one radar-based sensor, in particular a distance sensor (3), the radar-based sensor being arranged behind a vehicle part (4) according to any one of claims 1 to 11, the first coating (9) of the vehicle part (4) comprising a paint layer (12) applied to the outside of the motor vehicle, and the second coating of the vehicle part (4) facing the radar-based sensor.
14. A method for improving the permeability of a vehicle part (4) with respect to electromagnetic waves (5) of a specific frequency spectrum, in particular radar waves (5a, 5b), comprising: determining (S1) the reflectance R1 of a first coating (9) on a first surface, in particular a paint layer or a pigmented or painted plastic film (12) applied to the outside of the vehicle part (4); applying (S2) a second coating (10) to at least one section (15) of a second surface (8) of the vehicle component (4) opposite the first surface (7); Including, A method, wherein the reflectance R2 of the second coating (10) is matched to the reflectance R1 of the first coating (9).
15. The determining step (S1) determining the layer thickness of said first coating (9), and / or measuring the reflectance R1 of the first coating (9) applied to the support (6) of the vehicle component (4); 15. The method of claim 14, comprising:
16. The construction step (S2) painting said at least one section (15) of said second surface (8), in particular the inside of said vehicle part (4), with a paint comprising in particular an effect pigment (13); and / or adhesively bonding a film, in particular a self-adhesive metal foil or metallized plastic film (14), to said at least one section (15); 15. The method of claim 14, comprising:
17. A film set for improving the transmittance of electromagnetic waves (5) of a specific frequency spectrum, in particular radar waves (5a, 5b), said film set comprising a plurality of self-adhesive sections of metal foil or metallized plastic film (14), said sections differing in terms of their reflectivity and, optionally, in terms of their thickness.