Vehicle part intended to be placed facing an emission cone of a radar sensor of the vehicle and comprising a de-icing system provided with a thermal diffusion coating

Abstract

The invention relates to a part (2) for a vehicle which is intended to be arranged facing an emission cone of a radar sensor (4), the radar sensor (4) being configured to emit an electromagnetic wave (6) in the emission cone, the part (2) having, on one of its faces (10), a system (12) for de-icing the part (2), and the de-icing system (12) comprising a substrate (15) on which a set (13) of elongate heating elements (14) is arranged. According to the invention, the de-icing system (12) further comprises a thermal diffusion coating applied to the substrate (15).

Description

Vehicle part intended to be placed opposite an emission cone of a radar sensor of the vehicle and comprising a defrosting system provided with a thermal diffusion coating

[0001] The present invention belongs to the field of the integration of radar sensors within motor vehicles, and in particular to the field of defrosting systems for motor vehicles making it possible to maintain detection reliability by such radar sensors. The invention relates in particular to a vehicle part intended to be arranged opposite an emission cone of a radar sensor of the vehicle, and comprising such a defrosting system. State of the art

[0002] Self-driving or partially self-driving vehicles require a large number of sensors that are responsible for receiving redundant data from the vehicle's surroundings to avoid collisions and ensure that the vehicle arrives safely at its destination. These sensors, some of which are radar sensors, are placed in predetermined locations on the vehicle so that the data covers as much information as possible. The vehicle's lighting devices (headlights, taillights, etc.) are generally advantageous locations for such radar sensors, although other locations on the vehicle are also possible.

[0003] The electromagnetic wave emitted by such radar sensors is generally linearly polarized. By convention, the polarization of the electromagnetic wave describes the vibration of the electric field. When the wave is linearly polarized, this electric field oscillates in a single direction, this is the main polarization direction, classically a horizontal or vertical polarization direction.

[0004] One problem related to the integration of such a radar sensor in a motor vehicle lies in the need for the sensor to be able to detect external objects regardless of the weather conditions in which the vehicle is moving. However, for temperatures below the threshold of 0°C, a layer of frost is likely to form on the protective wall of the emission / reception location(s) of the radar sensor on the vehicle. Such a layer of frost then reflects and absorbs a very large part of the emitted radar waves, due to the very high refractive index of water. The range of the radar sensor can then be significantly reduced, and the detection functionality of the radar sensor may no longer be operational within the vehicle.This can lead to a malfunction of the ADAS (Advanced Driver-Assistance System) driver assistance system on board the vehicle, degrade the level of autonomous driving and ultimately increase the risk of driving.

[0005] In order to address this problem, it is known to use, upstream of the radar sensor reception location on the vehicle, a defrosting system to maintain the sensor's detection functionality.

[0006] Published patent document WO 2020 / 239380 A1 discloses, for example, such a defrosting system for a vehicle component subject to the problem of frost (such as a radar sensor, for example). The defrosting system is located outside the radar sensor's emission cone, on the edges of the sensor's receiving housing. The heat for defrosting is transmitted into the system via the use of an electrically conductive elastomer material. The electricity applied to the elastomer material produces the heat required for defrosting.

[0007] However, such a defrosting system cannot be arranged inside the emission cone of the sensor without altering the electromagnetic wave emitted by the sensor. As a result, the space available for the defrosting system on the sensor receiving housing on the vehicle is relatively restricted, as it is limited to the edges of the housing. This imposes a sizing constraint for the defrosting system, which substantially limits the defrosting speed. In addition, this defrosting speed is dependent on the electrical conductivity of the elastomer material used.

[0008] Other known solutions to the above-mentioned technical problem involve using a heating film as a defrosting system. Such a heating film allows the part opposite which the radar sensor is mounted to be defrosted, thus maintaining the radar sensor's good detectability. For example, US patent document 5,938,957 A describes such a heating film.

[0009] Heating films are divided into two categories: transparent heating films (whose heating wires are less than the eye's resolution) and visible heating films. Both types of heating films are made of metal wires, which, when electrically energized, provide the heating and therefore defrosting function. So-called "visible" heating films use embedded metal wires or printed conductive ink to provide electrical resistance, all at the millimeter scale. So-called "transparent" heating films are based on "metal mesh" technology, which consists of micro-scale metal wires (micrometer scale or smaller).

[0010] However, the solution of using a visible heating film has the disadvantage that the inter-wire distance (about 2.5 mm) is not suitable for ensuring good heating homogeneity. The solution of using a transparent heating film has the following disadvantages: to ensure good heating homogeneity, it is necessary for the distance between the wires to be very short, however the micro-mesh wires must be orthogonal to the polarization of the radar sensor so as not to alter the electromagnetic wave emitted by the sensor, which is restrictive; the micro-mesh of the wires also leads to a high electrical resistance which limits the heating power (therefore reduces the available current), which is not the case with visible heating films; finally, the micro-scale technology requires a lithography process (which represents an expensive technology).

[0011] The present invention improves the situation.

[0012] An objective of the invention is to propose a vehicle part intended to be arranged opposite an emission cone of a radar sensor of the vehicle, and comprising a defrosting system which can be arranged inside the emission cone of the radar sensor while offering improved thermal performance, while having an increased defrosting speed.

[0013] Another objective of the invention is to propose such a vehicle part comprising a so-called “visible” heating film which is free from the drawbacks of the prior art.

[0014] To this end, a first aspect of the invention relates to a vehicle part intended to be arranged opposite an emission cone of a radar sensor of the vehicle, the radar sensor being configured to emit an electromagnetic wave in the emission cone, said part having on one of its faces a system for defrosting the part, the defrosting system comprising a substrate on which are arranged a set of elongated heating elements. The emission cone of the radar sensor corresponds to the angular zone in which the sensor emits. This angular zone has a main direction which corresponds to the main propagation direction of the wave for which the amplitude of the wave is maximum.

[0015] According to the invention, the defrosting system further comprises a thermal diffusion coating applied to the substrate.

[0016] Thus, due to the presence of such a thermal diffusion coating applied to the substrate, the defrosting system has much better heating homogeneity. Indeed, local hot spots are eliminated by homogeneous thermal diffusion within the defrosting system. This makes it possible to significantly improve the thermal performance of the system. In addition, the defrosting speed is advantageously increased compared to prior art systems. Finally, the energy consumption of the defrosting system is advantageously low (while maintaining the same defrosting speed), and the manufacturing process of the system is less expensive.

[0017] According to one embodiment of the invention, the assembly consisting of the substrate, the elongated heating elements and the thermal diffusion coating (applied to the substrate) forms a heating film, preferably a so-called "visible" heating film (in other words with an inter-wire distance and / or a width of each wire on a millimeter scale).

[0018] According to one embodiment of the invention, the thermal diffusion coating is made of a semiconductor material.

[0019] According to a preferred embodiment of the invention, the semiconductor material is silicon. The use of silicon as the semiconductor material for the thermal diffusion coating makes it possible not to alter the electromagnetic wave emitted by the radar sensor. The use of silicon also makes it possible to manufacture the thermal diffusion coating in the form of a low-cost metalloid layer. Silicon also lies at the limit between a metalloid material and a dielectric material (which can generally be adjusted to be "transparent" to the electromagnetic wave emitted by the radar sensor). In the context of a particular vehicle center panel application (arranged for example on the front of the vehicle), an "aesthetic" metallic appearance can also be envisaged by using silicon. Silicon is an advantageous material combining an "aesthetic" metallic appearance and very good thermal conduction and diffusion.

[0020] As a less advantageous alternative, indium can be used instead of silicon as a semiconductor material for the thermal diffusion coating. However, indium, compared to silicon, has a less "aesthetic" metallic appearance and requires a less efficient "window" deposition process (shallower skin depth due to higher electrical conductivity and lower thermal conductivity of indium).

[0021] According to one embodiment of the invention, the thermal diffusion coating has a thermal conductivity greater than or equal to 100 W / mK.

[0022] According to one embodiment of the invention, the thermal diffusion coating has an electrical conductivity less than or equal to 1 S / m. This makes it possible not to alter the electromagnetic wave emitted by the radar sensor.

[0023] According to one embodiment of the invention, the thermal diffusion coating has a negative magnetic susceptibility. This makes it possible not to alter the electromagnetic wave emitted by the radar sensor. More precisely, such a negative magnetic susceptibility for the thermal diffusion coating makes it possible to prevent the electric field of the electromagnetic wave emitted by the radar sensor from interacting with the magnetic layer of the thermal diffusion coating, which allows the electromagnetic wave to pass "through" the part without being altered.

[0024] According to one embodiment of the invention, the elongated heating elements are printed on the thermal diffusion coating. In this case, each elongated heating element has a thickness of the order of ten microns. Alternatively, the elongated heating elements are arranged behind the thermal diffusion coating, on the substrate, and then have a greater thickness.

[0025] According to one embodiment of the invention, the elongated heating elements are printed on the thermal diffusion coating by depositing conductive ink by screen printing.

[0026] According to one embodiment of the invention, the thermal diffusion coating has a thickness of between 1 nm and 50 µm.

[0027] According to one embodiment of the invention, the substrate has a thickness greater than 250 µm, for example substantially equal to 1 mm.

[0028] According to one embodiment of the invention, the part further comprises a closing layer for the defrosting system, said closing layer being applied to the thermal diffusion coating. Such a closing layer makes it possible to protect the different layers of the defrosting system.

[0029] According to one embodiment of the invention, the closing layer of the defrosting system is made of a plastic material, preferably polycarbonate.

[0030] According to one embodiment of the invention, the elongated heating elements are heating wires or metal strips. The heating wires or metal strips are, for example, powered by a common power supply unit configured to circulate an electric current within each of the wires or metal strips. The heat required for defrosting is then produced by the Joule effect in the wires or metal strips. The power supply unit is, for example, connected to the heating wires or metal strips via one or more electrical connection elements (such as, for example, electrical current distribution strips, electrical cables and / or a power supply ribbon). These electrical connection elements, which are generally made of a non-transparent electrically conductive material, are arranged in the room outside the emission cone of the radar sensor.

[0031] According to one embodiment of the invention, each heating wire or metal strip is coated with a layer of a dielectric material or is arranged in a dielectric protective and insulating element.

[0032] According to one embodiment of the invention, the dielectric material has a refractive index and a thickness that is between 0.8 times and 1.2 times an ideal thickness, the ideal thickness being equal to a natural number multiplied by the wavelength of the electromagnetic wave emitted by the radar sensor and divided by two times the refractive index of the dielectric material. This ideal thickness is such that the electromagnetic waves reflected by the heating wires or metal strips undergo destructive interference, thus minimizing or even eliminating any attenuation of the signal from the radar sensor. The transmission of the signal through the wires or metal strips is thus maximized, regardless of the component of the electromagnetic wave considered. In certain particular cases, the thickness of the dielectric material is between 0.8 times and 1.2 times the wavelength divided by two times the refractive index.This thickness, which corresponds to the minimum possible for this embodiment of the invention, makes it possible to avoid other interferences.

[0033] According to one embodiment of the invention, the vehicle part is a styling part intended to mask the radar sensor.

[0034] For example, the style piece could be a logo or a central panel.

[0035] According to one embodiment of the invention, the vehicle part is a closing window for a lighting and / or signaling element in which the radar sensor is integrated.

[0036] Another subject of the invention relates to an assembly comprising a vehicle radar sensor and a vehicle part according to the invention, in which the radar sensor is configured to emit an electromagnetic wave in an emission cone, the vehicle part being arranged opposite the emission cone of the radar sensor.

[0037] According to one embodiment of the invention, the radar sensor is a millimeter radar sensor polarized in a horizontal or vertical polarization direction. The oscillation of the electric field of the electromagnetic wave then extends in the horizontal or vertical direction. The wavelength of the radar sensor is typically between 3.70 mm and 3.94 mm. This type of radar sensor is typically suitable for autonomous driving applications, and such a wavelength is advantageously suitable for detecting objects without excessive power consumption or response delay.

[0038] According to one embodiment of the invention, the assembly is a lighting and / or signaling element of a vehicle, in particular a vehicle headlight. For example, the vehicle part may be a closing glass of said lighting and / or signaling element, said glass constituting one face of said element. Such a lighting and / or signaling element may then house the radar sensor.

[0039] According to another embodiment of the invention, the assembly is a radome.

[0040] Here, "vehicle" means any type of vehicle such as a motor vehicle, a moped, a motorcycle, a storage robot in a warehouse, or any other machine capable of carrying at least one passenger or intended for the transport of people or objects.

[0041] “Electric cable” means one or more elongated electrically conductive element(s) surrounded by at least one electrically insulating layer, the electrically insulating layer being able to be in direct physical contact with the elongated electrically conductive element(s).

[0042] The term "power supply cable" also means a power supply element whose thickness is small compared to its length and width. It can be curved and have a given shape. Thus, the cable has two extended faces separated by a perimeter, this perimeter defining a thickness of the cable, which can be variable, for example decreasing from one end to the other.

[0043] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended drawings in which:

[0044] is a schematic representation, in perspective view, of an assembly comprising a radar sensor and a vehicle part according to one embodiment of the invention;

[0045] is a schematic representation, in side view, of the vehicle part of the; and

[0046] is a schematic representation, in front view, of the vehicle part of the.

[0047] In this document, unless otherwise indicated, the terms "upstream" and "downstream" refer to the direction of propagation of the electromagnetic beam in the object to which it refers and also to the direction of emission of the electromagnetic wave outside of said object.

[0048] Furthermore, everything called "rear" is on the upstream side while everything called "front" is on the downstream side.

[0049] The terms "horizontal", "vertical" or "transverse", "lower", "upper", "top", "bottom", "side" are defined in relation to the orientation of the part 2 according to the invention, intended to be mounted in the vehicle. In particular, in this application, the term "vertical" designates an orientation perpendicular to the horizon while the term "horizontal" designates an orientation parallel to the horizon.

[0050] In Figures 1 to 3, an orthogonal reference frame associated with the vehicle part 2 is shown. This reference frame is composed of three axes X, Y and Z, here called, respectively, longitudinal axis X, transverse axis Y and vertical axis Z. Detailed description

[0051] This is a schematic representation, in perspective view, of an assembly 1 comprising the part 2 for a vehicle according to the invention, and of its operating principle. The assembly 1 further comprises a radar sensor 4. Only a portion of the part 2 is shown in the figures for reasons of clarity. Without this being limiting within the scope of the present invention, the assembly 1 is for example a lighting and / or signaling element of a vehicle, in particular a vehicle headlight. In this case, the part 2 is typically a closing glass for the lighting and / or signaling element 1. The glass 2 then constitutes one face of this element 1. Alternatively, the part 2 may be a styling part intended to mask the radar sensor 4, such as for example a logo or a central panel. In this case, the assembly 1 may be a lighting and / or signaling element of a vehicle, or any other element of the vehicle.Alternatively, assembly 1 may be a radome.

[0052] The radar sensor 4 is configured to emit an electromagnetic wave 6 in an emission cone 7 (such an emission cone 7 is not shown in the but is visible in the). The electric field of the electromagnetic wave 6 emitted by the radar sensor 4 comprises a component E1 oscillating in a direction of interest P1. More precisely, this means that this component E1 of the electric field of the electromagnetic wave 6 extends, in projection in the plane S defined by the emission surface of the radar sensor 4, along the direction of interest P1. The direction of interest P1 of the electric field of the electromagnetic wave 6 corresponds to a preferred direction, perpendicular to the main propagation direction D1 of the wave 6, and according to which the component of interest E1 of the electric field E of the wave 6 oscillates.When the radar sensor 4 is linearly polarized along a main polarization direction (for example horizontal or vertical), the direction of interest P1 corresponds to this main polarization direction. In the exemplary embodiment illustrated in the, the direction of interest of the wave 6 is the vertical direction, corresponding to the vertical axis Z. According to this exemplary embodiment, the electric field of the electromagnetic wave 6 emitted by the radar sensor 4 is unpolarized. In a variant not shown, the electric field of the electromagnetic wave emitted by the radar sensor can be polarized vertically or horizontally, or else along any rectilinear direction other than the vertical or horizontal direction.

[0053] The electromagnetic wave 6 propagates along a main propagation direction D1. The emission cone 7 of the radar sensor 4 corresponds to the angular zone in which the radar sensor 4 emits. This angular zone has a main direction which corresponds to the main propagation direction D1 of the wave 6 for which the amplitude of the wave is maximum. Here, the main propagation direction D1 corresponds to the optical axis of the radar sensor 4. In the illustrated embodiment, the main propagation direction D1 is the longitudinal direction, corresponding to the longitudinal axis X in the figures.

[0054] The radar sensor 4 is typically a millimeter radar sensor, with a frequency modulated continuous wave, the operating frequency of which is typically between 76 GHz and 81 GHz. The radar sensor 4 is for example a long-range radar sensor (therefore with a small field of view) or medium-range radar sensor (therefore with a medium field of view). The wavelength of the radar sensor 4 is typically between 3.70 mm and 3.94 mm. This type of radar sensor is typically suitable for autonomous driving applications, and such a wavelength is advantageously suitable for detecting objects without excessive energy consumption or response delay.

[0055] As illustrated in Figures 1 and 3, the part 2 is arranged opposite the emission cone 7 of the radar sensor 4, in front of the latter. The part 2 has on one of its faces 10 an area in contact with the external atmosphere. The part 2 comprises on this face 10 a system 12 for defrosting the part 2. The defrosting system 12 comprises a substrate 15 on which are arranged a set 13 of elongate heating elements 14. As illustrated in Figures 2 and 3, the defrosting system 12 also comprises a thermal diffusion coating 17 applied to the substrate 15. Preferably, the elongate heating elements 14 are printed on the thermal diffusion coating 17. The elongate heating elements 14 are advantageously printed on the thermal diffusion coating 17 by depositing conductive ink by screen printing.The part 2 also comprises a defrosting system closure layer 12 (this closure layer not being shown in the figures for reasons of clarity). The defrosting system closure layer 12 is applied to the thermal diffusion coating 17, and is typically made of a plastic material, preferably polycarbonate.

[0056] The defrosting system 12 further comprises a power supply unit (not shown), connected to the elongated heating elements 14 via one or more electrical connection elements (such as, for example, electrical current distribution strips, electrical cables and / or a power supply sheet). These electrical connection elements, which are generally made of a non-transparent electrically conductive material, are arranged in the part 2 outside the emission cone 7 of the radar sensor. The power supply unit is configured to circulate an electric current within each of the elongated heating elements 14. Each elongated heating element 14 is typically a heating wire or metal strip. The heat required for defrosting is then produced by the Joule effect in the heating wires or metal strips 14.

[0057] The substrate 15 has a thickness e1 greater than 250 µm, for example substantially equal to 1 mm. Preferably, each heating wire or metal strip 14 is coated with a layer of a dielectric material or is arranged in a dielectric protection and insulation element (such a dielectric material or element not being shown in the figures for reasons of clarity). The dielectric material has a refractive index and a thickness. The thickness of the dielectric material is advantageously between 0.8 times and 1.2 times an ideal thickness, the ideal thickness being equal to a natural number multiplied by the wavelength of the electromagnetic wave 6 emitted by the radar sensor 4 and divided by twice the refractive index of the dielectric material. According to a particular exemplary embodiment, the thickness of the dielectric material is between 0.8 times and 1.2 times the wavelength divided by twice the refractive index.This thickness, which corresponds to the minimum possible for this particular characteristic of the invention, makes it possible to avoid other interferences.

[0058] All or part of the elongated heating elements 14 is located in the emission cone 7 of the radar sensor 4, as will be described in more detail later. Each elongated heating element 14 located in the emission cone 7 of the radar sensor 4 is arranged on the part 2 so as to extend in a direction substantially perpendicular to the direction of interest P1 of the electric field of the electromagnetic wave 6 emitted by the radar sensor 4. In the illustrated embodiment, this direction of extension of the elongated heating elements 14 is the transverse direction, corresponding to the longitudinal axis Y in the figures.In this way, the component of interest E1 of the electromagnetic wave 6 (and, where appropriate, the component of interest E2 of the electromagnetic wave 6b), which extends perpendicular to the direction of extension of the elongate heating elements 14, is not reflected by these elements 14 and is almost entirely transmitted to the other side of the defrosting system 12. In addition to its component of interest E1, the electric field of the electromagnetic wave 6 emitted by the radar sensor 4 includes other components 9a, 9b, 9c which each extend respectively, in projection in the plane S defined by the emission surface of the radar sensor 4, along a respective direction other than the direction of interest P1. As illustrated in the, these other components 9a, 9b, 9c of the electromagnetic wave 6 are reflected by the elongated heating elements 14 and are not transmitted to the other side of the defrosting system 12.In a variant not shown, when the radar sensor 4 is linearly polarized, the electric field of the electromagnetic wave 6 emitted by the radar sensor 4 consists of the component E1.

[0059] According to an embodiment of the invention, shown in Figures 1 to 3, the set 13 of elongated heating elements 14 is located in the emission cone 7 of the radar sensor 4. The elongated heating elements 14 are arranged in such a way that the distance d2 separating two adjacent elongated heating elements 14 is constant (such a distance d2 being visible in Figures 2 and 3 and being measured here in the vertical direction of the Z axis).

[0060] Preferably, the distance d2 separating two adjacent elongate heating elements 14 is less than the wavelength of the electromagnetic wave 6 emitted by the radar sensor 4. The distance d2 separating two adjacent elongate heating elements 14 is typically less than 3 mm, preferably between 20 nm and 1 µm, preferably substantially equal to 350 nm.

[0061] More preferably, the ratio between the width l2 of each elongate heating element 14 and the wavelength of the electromagnetic wave 6 emitted by the radar sensor 4 is less than 1 / 10, preferably substantially equal to 1 / 10 (the width being measured here in the vertical direction of the Z axis). The width l2 of each elongate heating element 14 (visible in FIGS. 2 and 3) is for example of the order of a micrometer or a millimeter, typically less than 100 nm, preferably substantially equal to 80 nm. It should be noted that in FIGS. 2 and 3, the distance d2 and the width l2 are not shown to scale.

[0062] In the embodiment of the part 2 described above, the distance between two adjacent elongate heating elements and the width of each elongate heating element are calculated so as to minimize the reflection of the wave 6 on the elongate elements, and therefore to maximize the transmission of this wave 6 on the other side of the elements. The calculation of these two parameters is a function of the type of polarization and the wavelength of the radar sensor 4, and of the angle of incidence of the wave 6.

[0063] The thermal diffusion coating 17 is advantageously made of a semiconductor material. Preferably, the semiconductor material is silicon (typically deposited on the substrate 15 via a physical vapor deposition process). More preferably, when the semiconductor material is silicon, the thermal diffusion coating 17 has a thermal conductivity greater than or equal to 100 W / mK, and / or an electrical conductivity less than or equal to 1 S / m, and / or a negative magnetic susceptibility. As illustrated in the, the thermal diffusion coating 17 has a thickness e2 for example between 1 nm and 50 µm. The assembly consisting of the substrate 15, the thermal diffusion coating 17 and the elongated heating elements 14 has a thickness for example substantially equal to 1.1 mm. It should be noted that in the, the thicknesses e1 and e2 are not shown to scale.

[0064] Alternatively, the thermal diffusion coating 17 may be made of indium, or any other semiconductor material.

[0065] The present invention is not limited to the embodiments described above as examples, but extends to other variants.

Claims

Part (2) for a vehicle intended to be arranged opposite an emission cone (7) of a radar sensor (4) of the vehicle, the radar sensor (4) being configured to emit an electromagnetic wave (6) in the emission cone (7), said part (2) having on one of its faces (10) a system (12) for defrosting the part (2), the defrosting system (12) comprising a substrate (15) on which are arranged a set (13) of elongate heating elements (14); characterized in that the defrosting system (12) further comprises a thermal diffusion coating (17) applied to the substrate (15). Part (2) for a vehicle according to claim 1, in which the thermal diffusion coating (17) is made of a semiconducting material. Part (2) for a vehicle according to claim 2, in which the semiconductor material is silicon. Part (2) for a vehicle according to claim 3, in which the thermal diffusion coating (17) has a thermal conductivity greater than or equal to 100 W / mK. Part (2) for a vehicle according to claim 3 or 4, in which the thermal diffusion coating (17) has an electrical conductivity less than or equal to 1 S / m. Part (2) for a vehicle according to any one of claims 3 to 5, in which the thermal diffusion coating (17) has a negative magnetic susceptibility. Part (2) for a vehicle according to any one of the preceding claims, in which the elongated heating elements (14) are printed on the thermal diffusion coating (17). Part (2) for a vehicle according to claim 7, in which the elongated heating elements (14) are printed on the thermal diffusion coating (17) by depositing conductive ink by screen printing. Part (2) for a vehicle according to any one of the preceding claims, in which the thermal diffusion coating (17) has a thickness of between 1 nm and 50 µm. Part (2) for a vehicle according to any one of the preceding claims, in which the substrate (15) has a thickness greater than 250 µm, for example substantially equal to 1 mm. Part (2) for a vehicle according to any one of the preceding claims, in which the part (2) further comprises a closing layer of the defrosting system (12), said closing layer being applied to the thermal diffusion coating (17). Part (2) for a vehicle according to claim 11, in which the closing layer of the defrosting system (12) is made of a plastic material, preferably polycarbonate. Part (2) for a vehicle according to one of the preceding claims, in which the elongated heating elements (14) are heating metal wires or strips. Part (2) for a vehicle according to the preceding claim, in which each heating wire or metal strip (14) is coated with a layer of a dielectric material or is arranged in a dielectric protective and insulating element. Vehicle part (2) according to one of the preceding claims, wherein the vehicle part (2) is a styling part intended to mask the radar sensor (4). Part (2) for a vehicle according to the preceding claim, in which the styling part is a logo or a central panel. Part (2) for a vehicle according to one of claims 1 to 14, in which the part (2) for a vehicle is a closing window for a lighting and / or signaling element (1) in which the radar sensor (4) is integrated. Assembly (1) comprising a vehicle radar sensor (4) and a vehicle part (2) according to one of the preceding claims, in which the radar sensor (4) is configured to emit an electromagnetic wave (6) in an emission cone (7), the vehicle part (2) being arranged opposite the emission cone (7) of the radar sensor (4). Assembly (1) according to the preceding claim, in which the radar sensor (4) is a millimeter radar sensor polarized in a horizontal or vertical polarization direction. Assembly (1) according to the preceding claim, in which the radar sensor (4) has an operating frequency of between 76 GHz and 81 GHz. Assembly (1) according to one of claims 18 to 20, wherein the assembly (1) is a lighting and / or signaling element of a vehicle, in particular a vehicle headlight, comprising a vehicle part according to one of claims 1 to 14, or 17. Assembly (1) according to the preceding claim, in which the part (2) for the vehicle is a closing glass for said lighting and / or signaling element (1), said glass constituting one face of said element (1).

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