Vehicle part intended to be arranged facing an emission and reception cone of a lidar detection sensor of the vehicle and comprising a de-icing system

Abstract

The invention relates to a vehicle part (2) intended to be arranged facing a LIDAR (4), the LIDAR (4) being configured to emit an electromagnetic wave (6) of which the electrical field comprises a component (E1) oscillating in a direction of interest (P1), the part (2) comprising a system (12) for de-icing the part (2). According to the invention, the de-icing system (12) comprises a set (13) of elongate heating elements (14), at least one sub-set of the set of elongate heating elements (14) being located in the emission cone of the LIDAR (4) and being configured so that each elongate heating element (14) of the sub-set is arranged on the part (2) so as to extend in a direction substantially perpendicular to the direction of interest (P1) of the electrical field of the electromagnetic wave emitted by the LIDAR when the part (2) is arranged facing the LIDAR (4).

Description

Vehicle part intended to be placed opposite a transmission and reception cone of a LiDAR detection sensor of the vehicle and comprising a defrosting system

[0001] The present invention belongs to the field of the integration of LiDAR (Light Detecting And Ranging) detection 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 LiDAR detection sensors. The invention relates in particular to a vehicle part intended to be arranged opposite a transmission and reception cone of a LiDAR detection 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 LiDAR (Light Detecting And Ranging) 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 LiDAR sensors, although other locations on the vehicle are also possible. These LiDAR sensors are remote sensing and ranging devices that use laser beams to measure precise distances and movements in real time.

[0003] The laser electromagnetic wave emitted by such LiDAR detection 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, typically a horizontal or vertical polarization direction.

[0004] One problem related to the integration of such a LiDAR detection 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 transmission / reception location(s) of the LiDAR detection sensor on the vehicle. Such a layer of frost then reflects and absorbs a very large part of the emitted LiDAR detection waves, due to the very high refractive index of water. The range of the LiDAR detection sensor may then be significantly reduced, and the detection functionality of the LiDAR detection sensor may no longer be operational within the vehicle.

[0005] In order to address this issue, it is known to use, at the location where the LiDAR detection sensor is received 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] Published patent document WO 2023 / 084057 A1 describes a vehicle headlamp comprising a light source (in the visible spectrum), a radar sensor and a LiDAR detection sensor which are integrated within a housing of the headlamp. However, a disadvantage of the arrangement proposed in this document is that the emission cones of the unpolarized light source of the radar sensor and the polarized light source of the LiDAR detection sensor overlap.

[0009] The present invention improves the situation.

[0010] An objective of the invention is to propose a vehicle part intended to be arranged opposite a transmission and reception cone of a LiDAR detection sensor of the vehicle, and comprising a defrosting system which can be arranged inside the transmission and reception cone of the LiDAR detection sensor without altering the electromagnetic wave emitted by the sensor and therefore without harming the efficiency of the latter, while having an increased defrosting speed.

[0011] To this end, a first aspect of the invention relates to a vehicle part intended to be arranged opposite an emission and reception cone of a LiDAR detection sensor of the vehicle, the LiDAR detection sensor being configured to emit a polarized electromagnetic wave in the emission and reception cone, the electric field of the electromagnetic wave emitted by the LiDAR detection sensor comprising a component oscillating in a direction of interest, the electromagnetic wave emitted by the LiDAR detection sensor propagating in a main propagation direction, said part having on one of its faces a system for defrosting the part. The emission and reception cone of the LiDAR detection 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.The direction of interest of the electric field of the electromagnetic wave corresponds to a preferred direction, perpendicular to the main propagation direction of the wave. The electric field of the electromagnetic wave emitted by the radar sensor can be unpolarized, or linearly polarized (typically in a vertical or horizontal direction, or in any rectilinear direction other than the vertical or horizontal direction). When the LiDAR detection sensor is linearly polarized in a main polarization direction (for example horizontal or vertical), which is very often the case for a LiDAR detection sensor using a laser wave, the direction of interest corresponds to this main polarization direction. In this case, the electric field of the wave only includes its direction of interest.

[0012] According to the invention, the defrosting system comprises a set of elongated heating elements, at least one subset of said set of elongated heating elements being located in the emission and reception cone of the LiDAR detection sensor when the part is arranged facing the LiDAR detection sensor and being configured so that each elongated heating element of said subset is arranged on the part so as to extend in a direction substantially perpendicular to the direction of interest of the electric field of the electromagnetic wave emitted by the LiDAR detection sensor when the part is arranged facing the LiDAR detection sensor.

[0013] Thus, due to the orientation of the elongated heating elements located in the emission and reception cone of the LiDAR detection sensor, which are arranged on the part so as to extend in a direction substantially perpendicular to the direction of interest of the electric field of the electromagnetic wave emitted by the LiDAR detection sensor, the defrosting system allows the component of interest of the electromagnetic wave to pass through. This component of interest is almost not reflected by the elongated heating elements and is almost entirely transmitted to the other side of the defrosting system. The system for defrosting the part according to the invention can thus be arranged inside the emission and reception cone of the LiDAR detection sensor without altering the electromagnetic wave emitted by the sensor and therefore without harming the effectiveness of the latter.Furthermore, by varying the number and density of the elongated heating elements, the defrosting speed is advantageously increased compared to prior art systems.

[0014] According to a preferred embodiment of the invention, the elongated heating elements extend in the same plane, said plane extending perpendicular to the main propagation direction of the electromagnetic wave emitted by the LiDAR detection sensor.

[0015] According to one embodiment of the invention, the elongated heating elements extend parallel to each other in said plane, the set of elongated heating elements forming a grid wave polarizer. Such a polarizer serves as a filter increasing the signal-to-noise ratio level.

[0016] According to one embodiment of the invention, the elongated heating elements are arranged in such a way that the distance separating two adjacent elongated heating elements is constant.

[0017] According to one embodiment of the invention, the distance separating two adjacent elongated heating elements is less than the wavelength of the electromagnetic wave emitted by the LiDAR detection sensor (the latter generally being between 800 nm and 3000 nm).

[0018] According to one embodiment of the invention, the distance separating two adjacent elongate heating elements is less than 20 µm, preferably between 20 nm and 1 µm, preferably substantially equal to 350 nm. Such a value of distance between elongate elements advantageously allows the face of the part carrying the defrosting system to have a quasi-continuous appearance for an observer, as well as to avoid potential diffraction phenomena. Indeed, such a distance value is less than the resolving power of the human eye. The part thus has an improved aesthetic appearance, by displaying a quasi-continuous metallic reflective appearance. In addition, such a value in the range of 20 nm to 1 µm advantageously makes it possible to avoid parasitic phenomena of wave diffraction, due to the elongate metallic heating elements.

[0019] According to one embodiment of the invention, the ratio between the width of each elongated heating element and the wavelength of the electromagnetic wave emitted by the LiDAR detection sensor is less than 1 / 10.

[0020] According to one embodiment of the invention, the width of each elongated heating element is less than 100 nm, preferably substantially equal to 80 nm.

[0021] 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 electrical 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 electrical 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 an electrical power supply ribbon).These electrical connection elements, which are usually made of a non-transparent electrically conductive material, are arranged in the room outside the emission and reception cone of the LiDAR detection sensor.

[0022] 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.

[0023] According to one embodiment of the invention, the vehicle part is a styling part intended to mask the LiDAR detection sensor.

[0024] For example, the style piece could be a logo or a central panel.

[0025] According to one embodiment of the invention, the vehicle part is a closing window for a lighting and / or signaling element in which the LiDAR detection sensor is integrated.

[0026] Another subject of the invention relates to an assembly comprising a vehicle LiDAR detection sensor and a vehicle part according to the invention, in which the LiDAR detection sensor is configured to emit an electromagnetic wave in an emission and reception cone, the electric field of the electromagnetic wave emitted by the LiDAR detection sensor comprising a component oscillating in a direction of interest, the electromagnetic wave propagating in a main propagation direction, the vehicle part being arranged opposite the emission and reception cone of the LiDAR detection sensor.

[0027] According to one embodiment of the invention, the LiDAR detection sensor is a LiDAR detection sensor polarized in a horizontal or vertical polarization direction. This allows for better propagation at low incidence through the material of the electromagnetic wave emitted by the LiDAR detection sensor. The wavelength of the LiDAR detection sensor is typically between 900 nm and 2000 nm. This type of LiDAR detection 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. Advantageously, the LiDAR detection sensor is horizontally polarized. When the LiDAR detection sensor is polarized in a horizontal polarization direction, this makes it possible to overcome Fresnel reflections at a high angle of incidence (in other words at an angle of incidence between 35 and 70 degrees).

[0028] According to one embodiment of the invention, the LiDAR detection sensor has an operating frequency of between 150 THz and 350 THz. Such a frequency value, advantageously selected in the frequency domain of infrared waves, makes it possible in particular to avoid parasitic reflections of the wave on puddles of water, patches of slush or even patches of ice. Indeed, when the LiDAR detection sensor is polarized in a horizontal polarization direction (and the elongated heating elements are arranged vertically), parasitic reflections of the sun on a puddle of water or frost are avoided. At a high angle of incidence, in fact, since sunlight is unpolarized, part of the light will be reflected and the other transmitted. However, the part of the light that is reflected can saturate the LiDAR detection sensor.

[0029] According to one embodiment, the assembly further comprises a vehicle radar sensor, the radar sensor being configured to emit an electromagnetic wave in an emission cone, the electric field of the electromagnetic wave emitted by the radar sensor comprising a component oscillating in a direction of interest, the electromagnetic wave propagating in a main propagation direction, the vehicle part being arranged opposite the emission cone of the radar sensor, such that each elongate heating element of said at least subset of the set of elongate heating elements of the defrosting system of the part extends in a direction substantially perpendicular to the direction of interest of the electric field of the electromagnetic wave emitted by the radar sensor. Advantageously, the LiDAR detection sensor and the radar sensor have the same polarization direction.This makes it possible to integrate both a LiDAR detection sensor and a radar sensor into the assembly, without altering the electromagnetic wave emitted by the two sensors and therefore without harming the efficiency of the latter. Furthermore, when the distance separating two adjacent elongated heating elements is less than 20 µm, preferably between 20 nm and 1 µm, preferably substantially equal to 350 nm, this works for both the LiDAR detection sensor and the radar sensor (when these two sensors have the same polarization direction).

[0030] According to one embodiment of the invention, the radar sensor is a millimeter radar sensor polarized in a horizontal or vertical polarization direction. Advantageously, the radar sensor is horizontally polarized.

[0031] According to one embodiment of the invention, the radar sensor has an operating frequency of between 76 GHz and 81 GHz.

[0032] 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 LiDAR detection sensor.

[0033] 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.

[0034] “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).

[0035] 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.

[0036] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended drawings in which:

[0037] is a schematic representation, in perspective view, of an assembly comprising a LiDAR detection sensor and a vehicle part according to a first embodiment of the invention;

[0038] is a schematic representation, in front view, of the vehicle part of the;

[0039] is a schematic representation, in side view, of the vehicle part of the; and

[0040] is a schematic representation of an electrical circuit equivalent to the configuration of the.

[0041] 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.

[0042] Furthermore, everything called "rear" is on the upstream side while everything called "front" is on the downstream side.

[0043] 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.

[0044] In Figures 1 to 4, 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

[0045] 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 LiDAR detection sensor 4. Preferably, and as illustrated in the, the assembly 1 also comprises a radar sensor 5. Only a portion of the part 2 is shown in the figures for reasons of clarity. Without this being limiting in the context 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 of 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 style part intended to mask the LiDAR detection sensor 4 (and the radar sensor 5, if applicable), such as for example a logo or a central panel.In this case, the assembly 1 may be a vehicle lighting and / or signaling element, or any other element of the vehicle.

[0046] The LiDAR detection sensor 4 is configured to emit an electromagnetic wave 6 in an emission and reception cone 7 (such an emission and reception cone 7 is not shown in the but is visible in the). The electric field of the electromagnetic wave 6 emitted by the LiDAR detection 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 and reception surface of the LiDAR detection 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 LiDAR detection 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 LiDAR detection sensor 4 is unpolarized. In a variant not shown, the electric field of the electromagnetic wave emitted by the LiDAR detection sensor can be polarized vertically or horizontally, or else along any rectilinear direction other than the vertical or horizontal direction.

[0047] The electromagnetic wave 6 propagates along a main propagation direction D1. The emission and reception cone 7 of the radar sensor 4 corresponds to the angular zone in which the LiDAR detection 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 LiDAR detection sensor 4. In the illustrated embodiment, the main propagation direction D1 is the longitudinal direction, corresponding to the longitudinal axis X in the figures.

[0048] The LiDAR detection sensor 4 is typically a frequency-modulated continuous wave LiDAR detection sensor, the operating frequency of which is typically between 150 THz and 350 THz. The LiDAR detection sensor 4 is for example a long-range (i.e., small field of view) or medium-range (i.e., medium field of view) LiDAR detection sensor. The wavelength of the LiDAR detection sensor 4 is typically between 900 nm and 2000 nm. This type of LiDAR detection 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.

[0049] The radar sensor 5 is configured to emit an electromagnetic wave 6b in an emission cone 7b (such an emission cone 7b is not shown in the but is visible in the). The electric field of the electromagnetic wave 6b emitted by the radar sensor 5 comprises a component E2 oscillating in a direction of interest P2. More precisely, this means that this component E2 of the electric field of the electromagnetic wave 6b extends, in projection in the plane S defined by the emission surface of the radar sensor 5, along the direction of interest P2. The direction of interest P2 of the electric field of the electromagnetic wave 6b corresponds to a preferred direction, perpendicular to the main propagation direction D2 of the wave 6b, and according to which the component of interest E2 of the electric field E of the wave 6b oscillates.When the radar sensor 5 is linearly polarized along a main polarization direction (for example horizontal or vertical), the direction of interest P2 corresponds to this main polarization direction. In the exemplary embodiment illustrated in the, the direction of interest of the wave 6b is the vertical direction, corresponding to the vertical axis Z. According to this exemplary embodiment, the electric field of the electromagnetic wave 6b emitted by the radar sensor 5 is unpolarized. In a variant not shown, the electric field of the electromagnetic wave emitted by the LiDAR detection sensor can be polarized vertically or horizontally, or else along any rectilinear direction other than the vertical or horizontal direction.

[0050] The electromagnetic wave 6b propagates along a main propagation direction D2. The emission cone 7b of the radar sensor 5 corresponds to the angular zone in which the radar sensor 5 emits. This angular zone has a main direction which corresponds to the main propagation direction D2 of the wave 6b for which the amplitude of the wave is maximum. Here, the main propagation direction D2 corresponds to the optical axis of the radar sensor 5. In the illustrated embodiment, the main propagation direction D2 is the longitudinal direction, corresponding to the longitudinal axis X in the figures.

[0051] The radar sensor 5 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 5 is for example a long-range radar detection sensor (therefore with a small field of view) or medium-range radar detection sensor (therefore with a medium field of view). The wavelength of the radar sensor 5 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.

[0052] As illustrated in Figures 1 and 2, the part 2 is arranged opposite the emission and reception cone 7 of the LiDAR detection sensor 4 (and the radar sensor 5, if applicable), 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.

[0053] The defrosting system 12 comprises a set 13 of elongated heating elements 14. 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 transmission and reception cone 7 of the LiDAR detection sensor 4 (and of the radar sensor 5, if applicable). 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.

[0054] Preferably, 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 (such a material or dielectric element not being shown in the figures for reasons of clarity).

[0055] All or part of the elongate heating elements 14 is located in the emission and reception cone 7 of the LiDAR detection sensor 4 (and, where appropriate, in the emission cone 7b of the radar sensor 5), as will be described in more detail later. Each elongate heating element 14 located in the emission and reception cone 7 of the LiDAR detection 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 LiDAR detection sensor 4 (and, where appropriate, to the direction of interest P2 of the electric field of the electromagnetic wave 6b emitted by the radar sensor 5). In the illustrated embodiment, this direction of extension of the elongate 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 LiDAR detection sensor 4 comprises other components 9a, 9b, 9c which each extend respectively, in projection in the plane S defined by the emission and reception surface of the LiDAR detection 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 LiDAR detection sensor 4 is linearly polarized, the electric field of the electromagnetic wave 6 emitted by the LiDAR detection sensor 4 consists of the component E1.

[0056] As illustrated in Figures 1 to 3, the elongated heating elements 14 extend in the same plane T. This plane T extends perpendicular to the main propagation direction D1 of the electromagnetic wave 6 emitted by the LiDAR detection sensor 4. In other words, the plane T in which the elongated heating elements 14 are arranged extends substantially parallel to the plane S defined by the emission and reception surface of the LiDAR detection sensor 4, in front of this plane S. In the particular embodiment shown in Figures 1 to 3, the elongated heating elements 14 extend parallel to each other in the plane T. The assembly 13 of the elongated heating elements 14 then forms a grid wave polarizer.

[0057] According to an embodiment of the invention, shown in Figures 1 to 3, the set 13 of elongate heating elements 14 is located in the emission and reception cone 7 of the LiDAR detection sensor 4 (and, where appropriate, in the emission cone 7b of the radar sensor 5). The elongate heating elements 14 are arranged in such a way that the distance d2 separating two adjacent elongate heating elements 14 is constant (such a distance d2 being visible on the and being measured here in the vertical direction of the Z axis).

[0058] Preferably, the distance d2 separating two adjacent elongate heating elements 14 is less than the wavelength of the electromagnetic wave 6 emitted by the LiDAR detection sensor 4. The distance d2 separating two adjacent elongate heating elements 14 is typically less than 20 µm, preferably between 20 nm and 1 µm, preferably substantially equal to 350 nm.

[0059] 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 LiDAR detection 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 on the) is typically less than 100 nm, preferably substantially equal to 80 nm. It should be noted that on the, the distance d2 and the width l2 are not shown to scale.

[0060] 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 LiDAR detection sensor 4, and of the angle of incidence of the wave 6, as will be detailed later.

[0061] More precisely, the configuration of the part 2 illustrated on theis schematized on theby an equivalent electrical circuit. In this equivalent electrical circuit, in which the LiDAR detection sensor 4 is polarized vertically in the direction P1 which is perpendicular to the direction of extension of the elongate heating elements 14, the parameters Y0 and B are given by the following equation (1):

[0062] [Math] (1) ;with ; << 1 ;d the distance between two adjacent elongated heating elements 14 ;a the sum of the width of an elongated heating element 14 and the distance d ;λ the wavelength of the LiDAR detection sensor 4 ;θ the angle of incidence of the electromagnetic wave 6 emitted by the LiDAR detection sensor 4.

[0063] When the angle of incidence θ of the electromagnetic wave 6 is 0 degrees, equation (1) becomes:

[0064] [Math] (1);

[0065] Based on the electrical diagram of the, the reflection coefficient R v of wave 6, which is a complex number, is then given by the following equation (2):

[0066] [Math] (2);

[0067] The distance d between two adjacent elongated heating elements 14 and the width ad of each elongated heating element 14 are then calculated so as to minimize the modulus of this reflection coefficient R v .

[0068] The present invention is not limited to the embodiments described above as examples; it extends to other variants, in particular to any variant in which at least one subassembly of the set of elongate heating elements 14 is located in the emission and reception cone 7 of the LiDAR detection sensor 4 (and, where appropriate, in the emission cone 7b of the radar sensor 5) and is configured so that each elongate heating element 14 of the subassembly 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 LiDAR detection sensor 4 (and, where appropriate, to the direction of interest P2 of the electric field of the electromagnetic wave 6b emitted by the radar sensor 5).

Claims

Part (2) for a vehicle intended to be arranged opposite a transmission and reception cone (7) of a LiDAR detection sensor (4) of the vehicle, the LiDAR detection sensor (4) being configured to emit an electromagnetic wave (6) in the transmission and reception cone (7), the electric field of the electromagnetic wave (6) emitted by the LiDAR detection sensor (4) comprising a component (E1) oscillating in a direction of interest (P1), the electromagnetic wave (6) emitted by the LiDAR detection sensor (4) propagating in a main propagation direction (D1), said part (2) having on one of its faces (10) a system (12) for defrosting the part (2);characterized in that the defrosting system (12) comprises a set (13) of elongate heating elements (14), at least one subset (16) of said set (13) of elongate heating elements (14) being located in the emission and reception cone (7) of the LiDAR detection sensor (4) when the part (2) is arranged opposite the LiDAR detection sensor (4) and being configured so that each elongate heating element (14) of said subset (16) 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 emitted by the LiDAR detection sensor (4) when the part (2) is arranged opposite the LiDAR detection sensor (4).; Part (2) for a vehicle according to claim 1, in which the elongated heating elements (14) extend in the same plane (T), said plane (T) extending perpendicular to the main propagation direction (D1) of the electromagnetic wave (6) emitted by the LiDAR detection sensor (4). Part (2) for a vehicle according to claim 2, in which the elongate heating elements (14) extend parallel to each other in said plane (T), the assembly (13) of elongate heating elements (14) forming a grid wave polarizer. Part (2) for a vehicle according to claim 3, in which the elongate heating elements (14) are arranged so that the distance (d2) separating two adjacent elongate heating elements (14) is constant. Part (2) for a vehicle according to claim 4, in which the distance (d2) separating two adjacent elongated heating elements (14) is less than the wavelength of the electromagnetic wave (6) emitted by the LiDAR detection sensor (4). Part (2) for a vehicle according to claim 4 or 5, in which the distance (d2) separating two adjacent elongated heating elements (14) is less than 20 µm, preferably between 20 nm and 1 µm, preferably substantially equal to 350 nm. Part (2) for a vehicle according to one of claims 3 to 6, in which the ratio between the width (l2) of each elongated heating element (14) and the wavelength of the electromagnetic wave (6) emitted by the LiDAR detection sensor (4) is less than 1 / 10. Part (2) for a vehicle according to the preceding claim, in which the width (l2) of each elongated heating element (14) is less than 100 nm, preferably substantially equal to 80 nm. 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 LiDAR detection 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 10, in which the part (2) for a vehicle is a closing window for a lighting and / or signaling element (1) in which the LiDAR detection sensor (4) is integrated. Assembly (1) comprising a vehicle LiDAR detection sensor (4) and a vehicle part (2) according to one of the preceding claims, wherein the LiDAR detection sensor (4) is configured to emit an electromagnetic wave (6) in an emission and reception cone (7), the electric field of the electromagnetic wave (6) emitted by the LiDAR detection sensor (4) comprising a component (E1) oscillating in a direction of interest (P1), the electromagnetic wave (6) propagating in a main propagation direction (D1), the vehicle part (2) being arranged opposite the emission and reception cone (7) of the LiDAR detection sensor (4). Assembly (1) according to the preceding claim, in which the LiDAR detection sensor (4) is a LiDAR detection sensor polarized according to a horizontal or vertical polarization direction. Assembly (1) according to the preceding claim, in which the LiDAR detection sensor (4) has an operating frequency of between 150 THz and 350 THz. Assembly (1) according to one of claims 14 to 16, wherein the assembly (1) further comprises a vehicle radar sensor (5), the radar sensor (5) being configured to emit an electromagnetic wave (6b) in an emission cone (7b), the electric field of the electromagnetic wave emitted by the radar sensor (5) comprising a component (E2) oscillating in a direction of interest (P2), the electromagnetic wave (6) propagating in a main propagation direction (D2), the part (2) for vehicle being arranged opposite the emission cone (7b) of the radar sensor (5), so that each elongate heating element (14) of said at least one sub-assembly (16) of the assembly (13) of elongate heating elements (14) of the defrosting system (12) of the part (2) extends in a direction substantially perpendicular to the direction of interest (P2) of the electric field of the electromagnetic wave (7b) emitted by the radar sensor (5). Assembly (1) according to the preceding claim, in which the radar sensor (5) 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 (5) has an operating frequency of between 76 GHz and 81 GHz. Assembly (1) according to one of claims 14 to 19, wherein the assembly (1) is a lighting and / or signaling element of a vehicle, in particular a vehicle headlight. 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).

Images