阅读说明：本技术 背光雷达保护装置 (Backlight radar protection device ) 是由 弗雷德里克·史泰布罗 阿莱丁·兰度尔斯 于 2020-02-25 设计创作，主要内容包括：一种机动车辆的雷达(2)保护装置(1),其包括由对于雷达波和可见光均透明的材料形成的主体(12)、对于光不透明但对于雷达波(4)透明的支承件(14),和布置在所述支承件(14)与所述主体(12)之间的发光元件(18),在所述支承件(14)与所述主体(12)之间设置有气腔(16),所述支承件(14)和所述主体(12)在它们的边缘上优选地以密封的方式相互组装,其中,所述腔(16)的厚度介于1/2雷达波波长至12倍雷达波波长之间,即大约2mm至48mm之间。(A radar (2) protection device (1) for a motor vehicle, comprising a body (12) formed of a material transparent to both radar waves and visible light, a support (14) opaque to light but transparent to radar waves (4), and a light emitting element (18) arranged between the support (14) and the body (12), an air cavity (16) being provided between the support (14) and the body (12), the support (14) and the body (12) being assembled to each other on their edges, preferably in a sealed manner, wherein the thickness of the cavity (16) is between 1/2 radar wave wavelengths and 12 radar wave wavelengths, i.e. between about 2mm and 48 mm.)

1. A radar (2) protection device (1) of a motor vehicle, comprising a body (12) formed of a material transparent to radar waves and visible light, a support (14) opaque to light but transparent to radar waves (4), and a light-emitting element (18) arranged between the support (14) and the body (12), an air cavity (16) being provided between the support (14) and the body (12), the support (14) and the body (12) being assembled to each other on their edges, preferably in a sealed manner, characterized in that the thickness of the cavity (16) is between 1/2 radar wave wavelengths and 12 times radar wave wavelengths, i.e. between about 2mm and 48 mm.

2. The radar (2) protection device (1) for motor vehicles according to claim 1, wherein the thickness of the cavity (16) is 1 to 2 times the wavelength of the radar waves, i.e. about 4 to 8 mm.

3. Radar (2) protection arrangement (1) for a motor vehicle according to any one of the preceding claims, wherein the light emitting element (18) is located in the air cavity (16) and arranged on the support (14) and the light emitting element (18) only partially covers the surface of the support (14).

4. The radar (2) protection device (1) for a motor vehicle according to any one of the preceding claims, wherein said light emitting element (18) is transparent to said radar waves.

5. The radar (2) protection device (1) for a motor vehicle according to any one of the preceding claims, wherein said light emitting element (18) comprises an optical fiber.

6. The radar (2) protection device (1) of a motor vehicle according to any one of claims 1 to 3, wherein the light emitting element (18) comprises an Organic Light Emitting Diode (OLED).

7. The device according to claim 1 or 2, wherein the light emitting element (18) is arranged at an end of the support (14).

8. Radar (2) protection device (1) for a motor vehicle according to any one of the preceding claims, wherein the body (12) is partially covered by a coating that is opaque to light but transparent to the radar waves, forming a decorative pattern (124).

9. Radar (2) protection device (1) for a motor vehicle according to any one of the preceding claims, wherein the overall thickness of the protection device (1) is substantially constant and less than or equal to 6 mm.

10. Radar (2) protection arrangement (1) for a motor vehicle according to any one of the preceding claims, wherein the inner face (122) of the body (12) is substantially flat.

11. Radar (2) protection arrangement (1) for a motor vehicle according to any one of claims 1 to 7, wherein the interior face (122) of the body comprises reliefs (126) configured to enable an improved aesthetic effect of the protection arrangement.

Technical Field

The present invention relates to the field of motor vehicles equipped with radars, and more particularly to the field of devices for screening and protecting such radars (also called "radomes").

The device according to the invention is particularly suitable for radars, for example of the ACC type, arranged in the front or rear bumper of a vehicle.

Background

For safety reasons in particular, it is known to equip motor vehicles with radar of the ACC (english term "Adaptive Cruise Control") type, for example. Such radars are used in particular for regulating the vehicle speed in dependence on traffic and/or obstacles on the road. The radar detects the speed and distance of objects in front of its carrier vehicle in order to maintain a safe distance, in particular between vehicles.

Depending on their function, radars are mounted on the front or rear face of the vehicle. In order to conceal these radars, whether for the purpose of protecting them from external aggressions (rain, ice, frost, sludge, insects, foliage, etc.) or for aesthetic reasons, it is known to use "radomes", i.e. protective parts comprising a plastic shade arranged in front of the radar.

Such plastic masks let radar waves pass with as little attenuation as possible, so as not to interfere with the operation of the radar itself.

A decorated radome consisting of two plates made of plastic has been proposed in application US 2014/0218263. In the radome, a decorative metal layer has been vapor deposited on one of the plates to reveal a decorative pattern. A drawback of this manner of decoration is that it is only visible when the vehicle is illuminated, in particular in daylight.

A radome is also known from patent JP5132656, all parts of which are transparent to radar waves. The radome comprises a logo (decorative element) and a frame, and it further comprises a light guide connected to a light source arranged between the logo and the frame. The frame is transparent to radar waves but opaque to visible light, and the exposed surface of the frame facing the light guide is a reflective surface. Furthermore, the logo is transparent to light in certain parts of it, so that it enables the pattern to appear when it is backlit. Backlighting is provided by an LED-driven light guide consisting of a rectangular resin plate comprising on its rear face specially shaped V-shaped grooves having a special shape necessary for uniform diffusion of light. The light guide is complex, which in addition means that the shape of the slot is also designed to avoid interfering with the transmission of the radar waves.

Disclosure of Invention

The object of the present invention is to remedy the drawbacks of the decorated radomes of the prior art backlit by providing a backlit radome by means of a light emitting element that does not require any complex implementation, neither in terms of the light emitting element nor in terms of the whole radome, ensuring a satisfactory radar wave transmission while producing an effective backlight.

To this effect, the subject of the invention is a radar protection device for a motor vehicle, comprising a body formed from a material transparent to radar waves and visible light, a support opaque to light but transparent to radar waves, and a light-emitting element arranged between the support and the body, wherein an air cavity is provided between the support and the body, the support and the body being assembled to each other on their edges, preferably in a sealed manner, and wherein the thickness of the cavity is between 1/2 radar wave wavelengths and 12 radar wave wavelengths, i.e. between about 2mm and 48 mm. The provision of an air cavity is advantageous because it allows better transmission of radar waves and also because it makes the manufacture of the radar protection device easier, in particular avoids the light emitting element being damaged during manufacture. Further, tests conducted by the present inventors have shown that the transmittance of radar waves is higher for air cavity thicknesses in the above range.

Advantageously, the thickness of the air cavity is 1 to 2 times the wavelength of the radar wave, i.e. about 4 to 8 mm. In this interval, the transmittance of the radar wave is optimal.

The protection device may additionally comprise one or more of the following features taken alone or in combination:

the light-emitting element is located in the air cavity and arranged on the support, and the light-emitting element only partially covers the surface of the support.

The light-emitting element is transparent to radar waves. This feature is particularly advantageous when the light emitting element is arranged in front of the radar.

The light emitting element comprises an optical fiber. The optical fiber has good adaptability to, for example, a bent or convex shape. Also, the brightness of the fiber was used (1600 candelas per square meter (cd. m) for a surface of 10x400mm^-2) A luminance of about 200cd. m) than is known using the prior art^-2Higher than the flat light guide. Thus, the use of optical fibers can produce brighter light-emitting decorative elements under the same intensity of light source. Conventionally, it is considered that uniformity of thickness of the radome or the thickness of the layers constituting the radome is very important for realizing the radome function. In a light guide constituted by an optical fiber, the thickness thereof is not uniform (columns arranged side by side) and the surface is not smooth. The use of optical fibers as light guides in radomes is therefore unnatural, since it will be assumed that the optical fibers will attenuate radar waves. Furthermore, the presence of heterogeneous materials, which may exhibit different characteristics and different thicknesses, may be felt as a radome comprising such a light guide that does not have uniform characteristics. The inventors have demonstrated that the optical fiber has a radar wave attenuation compatible with the requirements of motor vehicle manufacturers. Alternatively, the optical fibers are arranged in a sheet (layer) or strand shape.

The light emitting element comprises an Organic Light Emitting Diode (OLED). The OLED can form a light emitting panel having a small thickness and good light emission uniformity. These panels are generally flexible.

The light emitting elements are arranged at the ends of the support. Preferably, the light emitting element is constituted by an LED. Thus, the transmission of the radar wave is not disturbed at all by the presence of the light emitting element. In this case, the entire cavity is illuminated by the LEDs arranged on the ends of the support.

The body is locally covered by a coating that is opaque to light but transparent to radar waves, forming a decorative pattern. Thereby, the edge of the decoration is illuminated by a halo matching the shape of the decoration.

-the total thickness of the protection device is substantially constant and less than or equal to 6 mm. This allows maintaining a good transparency to radar waves.

The inner face of the body is substantially flat. This allows for simplified device manufacturing.

The inner face of the body comprises reliefs configured so as to enable an improved aesthetic effect of the protection device.

The decorative coating has a metallized appearance. The appearance thereof is thus harmonious with the usual aesthetic appearance of motor vehicles.

The decorative coating is obtained by a colour or texturing treatment.

The decorative coating is obtained by techniques known to those skilled in the art, such as hot stamping techniques (pressing the film against the surface during printing), or by overmolding a metallized film (for example by depositing beforehand a thin coating providing the metallic appearance, the layer being about 0.5 μm), or by applying a chrome lacquer, or by vapor Deposition ("PVD") of a metal such as indium, gold, tin. Because indium, gold, and tin do not interfere with radar wave transmission, the use of these techniques and these materials can impart a metallized appearance to the radome. Another advantage of these different techniques is that it is possible to obtain very thin thicknesses and to ensure transparency of the cladding to light when the light source is activated, while ensuring that the cladding blocks the light source by reflecting ambient light when the light source is extinguished.

The light guide is made of one or more plastic films, for example a transparent film made of extruded polycarbonate, having a transmission rate according to ISO13468-2 of greater than or equal to 90% and a refractive index according to ISO 62 of 1.584.

The optical fiber can be connected to a light source located outside the area facing the radar transmission area. This arrangement can avoid interfering with radar operation.

The support and the body are made of Polymethylmethacrylate (PMMA), the support being opaque and the body being transparent.

The support is made of ASA (acrylonitrile styrene acrylate) or ABS-PC (acrylonitrile butadiene styrene/polycarbonate). The body is made of polycarbonate.

The opaque support is a component transparent to light and to radar waves, preferably obtained by injection, onto which a resin opaque to light but transparent to radar waves is poured or over-injected. The opaque resin may be polyurethane.

The subject of the invention is also a method for assembling said protection device, comprising the following steps:

mounting a light emitting element on the interior face of the support;

the body and the support are sealingly assembled by any suitable means, for example by gluing.

The assembly method may additionally include one or more of the following steps taken alone or in combination:

depositing a decorative overlay on the interior face of the body;

encapsulating the light emitting elements on the inner face of the support in a resin;

the opaque support is made by injecting a part transparent to light and to radar waves, and applying a resin opaque to light but transparent to radar waves on the external face of the part, preferably after the steps of mounting the light-emitting elements and depositing the decorative coating.

The opaque material filled in the back of the assembly of transparent part, decorative cover and light emitting element can be cast at a lower temperature and pressure than the injection of the transparent material. Thus, by covering the support with an opaque resin after the light guide is mounted and the decorative coating is deposited, it is possible to maintain the arrangement positioning and optical quality of the light guide and the decorative coating without damaging the transparent member.

Drawings

The invention will be better understood on reading the following description, provided by way of example only, with reference to the accompanying drawings, in which:

fig. 1 is a perspective view of the front face of a motor vehicle including a radar protection device according to an embodiment of the present invention.

Fig. 2 is a side section of a radar protection device of a motor vehicle according to a first embodiment, wherein the light emitting element partially covers the support.

Fig. 3 is a partial enlarged side section of the radar protection device of the motor vehicle according to the embodiment of fig. 2.

Fig. 4 is a side cross-section of a second embodiment of the invention, wherein the light emitting elements are LEDs arranged at the ends of the support.

Detailed Description

Fig. 1 to 3 show a radar protection device for a motor vehicle according to a first embodiment of the invention, which is designated by reference numeral 1.

Fig. 1 shows schematically and without limitation the position of the radar protection device on the front face of the vehicle.

Fig. 2 and 3 show a first embodiment of a protection device 1 for a radar 2. In the following of this description the term "radome" is used as a synonym for "protection means". The radar 2 is arranged behind the protection device 1. Radar waves 3 transmitted or received by the radar 2 pass through the radome 1. Radome 1 includes a body 12, shown here as a generally flat plate, but this shape is merely illustrative and not limiting. For example, the body 12 may be curved in other embodiments. The radome also includes a support 14. The body 12 and the support 14 are assembled to each other on their respective edges. The assembly is preferably sealed. The sealing is achieved by any suitable means known to the person skilled in the art, for example by gluing. A light-emitting element 18 is fixed to the support 14.

An air chamber 16 is provided between the main body 12 and the support 14. The presence of this air cavity 16 brings about a number of advantages. On the one hand, it enables an easy manufacturing of the radome 1, while avoiding the risk of damaging the light emitting elements 18 during this manufacturing process. On the other hand, it enables better transmission of radar waves by radome 1. The presence of air cavity 16 further enhances the transmission of radar waves when the thickness of air cavity 16 is between 1/2 wavelengths and 12 wavelengths of radar waves. Radars used in motor vehicles typically have a frequency of 77GHz, so their wavelength is about 4 mm. Thus, advantageously, air cavity 16 has a thickness of 2mm to 48 mm. The transmission of radar waves in radome 1 is optimal when the thickness of air cavity 16 is 1 to 2 times the wavelength of the radar waves, i.e. 4mm to 8 mm.

In one embodiment, the light emitting element 18 comprises an optical fiber. The optical fibre may be made of plastic, for example PMMA (polymethylmethacrylate) or other polymers, or glass. The optical fibers may be woven using conventional textile threads, such as polyester, to form a light-emitting fabric layer (or sheet). Tests carried out by the inventors have confirmed that such fibers are transparent to radar waves. The light emitting element 18 comprising the optical fiber thus does not interfere with the operation of the radar. The optical fiber may be supplied by a light source consisting of one or more LEDs. Advantageously, the one or more light sources are offset in an area not covered by radar waves so as not to interfere with their transmission.

In another embodiment, the light emitting element 18 comprises an OLED (organic light emitting diode). The light emitting element 18 may for example be a flexible light emitting panel. The OLED is preferably transparent to radar waves.

In yet another embodiment, the light-emitting elements 18 are light guides composed of a film made of an extruded polycarbonate transparent plastic having a light transmission rate according to ISO13468-2 of greater than or equal to 90% and a refractive index according to ISO 62 of 1.584.

These light guides are diffuse, i.e. the exit surface of the light is formed by the side faces of the light guide. Thereby, light exits from the light guide in a substantially radial direction, and the delivered light flux is substantially constant at any point of the exit surface of the diffusive portion of the light guide.

The body 12 is made of a polymer material transparent to visible light and radar waves. Non-exclusively, the material may be selected from PMMA (polymethylmethacrylate), polycarbonate, polypropylene, polyamide, copolyester (copolyester), acrylonitrile butadiene styrene, acrylonitrile styrene acrylate, styrene acrylonitrile, a mixture of acrylonitrile styrene acrylate and polycarbonate, a mixture of polycarbonate and poly terephthalic acid.

In one embodiment, visible in fig. 2, the interior face 122 of the body 12 is substantially smooth, which simplifies manufacturing.

In another embodiment, visible in fig. 3, the inner face 122 of the body 12 comprises reliefs 126. The relief is configured to improve the aesthetic rendering of the radome 1.

In another embodiment visible in fig. 4, the light emitting element 18 is offset on the end of the support 14. In this embodiment, light emitting element 18 illuminates the entire air cavity 16. Preferably, the light emitting elements 18 are LEDs.

In some cases, it is desirable to obtain on the radome 1 a decoration element or pattern that appears when it is backlit. In this embodiment, a decorative coating or film 124 is formed on the body 12, preferably on its interior surface 122 for better durability. The decorative overlay 124 may be designed to have a metallized appearance. It can be obtained by hot stamping techniques. Over-molding of metallized films, or chrome lacquers, may also be used. Finally, vapor Deposition ("PVD") techniques can also be used. Whereby a metal such as indium, gold or tin can be deposited.

In one embodiment, the support 14 is made of a polymeric material that is opaque to visible light but transparent to radar waves. Without limitation, the polymeric material may be Polycarbonate (PC), polypropylene, polymethylmethacrylate, polyamide, copolyester, or Acrylonitrile Butadiene Styrene (ABS), ASA, ABS-PC, and mixtures thereof, such as copolymers.

Preferably, the support 14 is black.

The support 14 and the body 12 are generally made by injection molding a suitable polymeric material selected from, but not limited to, the polymeric materials described above. The individual components are then assembled.

In one assembly step, the light-emitting element 18 is fixed on the inner face of the support 14, for example by gluing or by mechanical means.

Then, in a further step, the body 12 and the support 14 are assembled by any suitable means, preferably in a sealed manner, for example by gluing their respective edges, or by mechanical fixing, possibly including a seal.

In one embodiment, a decorative overlay 124 is deposited on the interior face 122 of the body 12, typically according to one of the techniques described above (hot stamping, film overmolding, chrome paint, PVD). Of course, the deposition of the decorative coating 124 is performed before the assembly of the body 12 and the support 14.

In one embodiment, the light emitting element 18 is encapsulated in a resin after it is secured to the interior face of the support 14. This allows improving its durability.

In one embodiment, the opaque support 14 is obtained by: a plastic transparent to light and to radar waves is injected, then a resin opaque to light but transparent to radar waves is applied on the external face of the transparent piece thus obtained, preferably after the steps of mounting the light-emitting elements 18 and depositing the decorative coating 124.

Thus, the opaque resin is filled in the back surface of the assembly of the transparent member, the decorative coating and the light emitting element, and the opaque resin can be poured at a temperature and pressure lower than those at which the transparent resin is injected. Thus, by covering the support with an opaque resin after the light emitting elements are mounted and the decorative coating is deposited, it is possible to maintain the arrangement positioning and optical quality of the light emitting elements and the decorative coating without damaging the transparent member.