Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/42—Housings not intimately mechanically associated with radiating elements, e.g. radome
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/27—Adaptation for use in or on movable bodies
  • H01Q1/32—Adaptation for use in or on road or rail vehicles
  • H01Q1/3208—Adaptation for use in or on road or rail vehicles characterised by the application wherein the antenna is used
  • H01Q1/3233—Adaptation for use in or on road or rail vehicles characterised by the application wherein the antenna is used particular used as part of a sensor or in a security system, e.g. for automotive radar, navigation systems
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/27—Adaptation for use in or on movable bodies
  • H01Q1/32—Adaptation for use in or on road or rail vehicles
  • H01Q1/325—Adaptation for use in or on road or rail vehicles characterised by the location of the antenna on the vehicle
  • H01Q1/3283—Adaptation for use in or on road or rail vehicles characterised by the location of the antenna on the vehicle side-mounted antennas, e.g. bumper-mounted, door-mounted
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/42—Housings not intimately mechanically associated with radiating elements, e.g. radome
  • H01Q1/422—Housings not intimately mechanically associated with radiating elements, e.g. radome comprising two or more layers of dielectric material

Definitions

• Radome for a motor vehicle comprising a decorative pattern
• the invention relates to motor vehicles equipped with wave-emitting members and more particularly the protection devices configured to protect these wave-emitting members from motor vehicle.
• More and more motor vehicles have body parts on which are mounted members emitting waves.
• These wave emission devices are, for example, one or more ACC type radars according to the English expression “Adaptive Cruise Control” emitting radio waves.
• radomes Such wave-emitting devices are masked and protected, for example from bad weather, by protective devices commonly called “radomes”.
• radomes In the remainder of the description, the term “radome” is used as a synonym for “protection device”.
• radomes are intended to be crossed by the waves emitted by the transmitting device (s), so they must be transparent to them.
• transparent to the waves emitted by a wave-emitting member is meant the capacity of a material traversed by an incident wave flow to transmit a fraction greater than 90% of the wave flow passing through it.
• the thickness of the region intended to be placed in front of a radar is chosen from a set of pairs of attenuation and reflection values of the radar waves / thickness of the region.
• This set of couples is obtained for example by measurements and calculations of attenuation and reflection of the waves as a function of the thickness, and also as a function of parameters such as the dielectric properties of the materials used for the manufacture of the part, the varnish or the paint applied to the surface of the part, in particular the different layers and their different thicknesses which make it possible to obtain a paint for automotive application, such as the primer, the base and the varnish.
• protection devices may have an aesthetic vocation, as is for example described in application FR 3 070 547 A1 in which the radome comprises luminous means diffusing light through the radome so as to form a pattern. on the surface of the latter, pattern visible from the outside of a vehicle on which the radome is mounted.
• the latter is therefore partly transparent to visible light.
• transparent to visible light is understood to mean that it is at least transparent or translucent to any light radiation. exhibiting a wavelength included in the visible spectrum, that is to say between approximately 380 and 780 nm.
• the decorative pattern can be achieved by covering certain areas with paint opaque to visible light, other areas not being covered by this paint, the lighting of the radome making it possible to reveal the decorative motif (area through which the light passes if the pattern is formed by areas through which light passes or does not pass if the pattern is formed by areas through which light does not pass).
• the paint used for example to obtain a high-quality visual rendering, is not transparent to the waves emitted by a wave-emitting device. This poses a problem because certain paints cannot therefore be used to paint a radome.
• the object of the invention is in particular to provide a radome making it possible to solve simply this problem of disturbance of the propagation of the waves while maintaining a radome having an optimal visual appearance.
• the invention relates to a radome for a motor vehicle comprising a main body comprising at least one zone transparent to the waves emitted by the wave-emitting member and intended to be traversed by said waves, the zone comprising a face comprising an alternation of first parts covered by at least one layer of paint and second parts not covered by said layer of paint, the first and second parts forming at least one decorative pattern and being arranged so as to make the decorative pattern transparent to waves emitted by the wave-emitting device.
• the first parts form bands with a width equal to (N * l) / 4, N being a non-zero natural whole number and l being equal to the emission wavelength of the emission member d 'waves,
• the second parts form bands with a width of less than h / 4 separated from each other by the first parts
• the second parts form bands with a width greater than h / 4 separated from each other by the first parts
• the first parts and the second parts are rectilinear bands parallel to each other
• the first parts and the second parts extend at least partly in a direction perpendicular to a plane in which propagate the waves emitted by the wave-emitting member
• the radome comprises a light guide facing the decorative pattern and arranged to diffuse visible light through the second parts, preferably comprising a bundle of optical fibers,
• the main body (8) is made of a material chosen from polymethyl methacrylate, polycarbonate, polypropylene, a polyamide, a copolyester, acrylonitrile butadiene styrene, acrylonitrile styrene acrylate, styrene acrylonitrile, a mixture of acrylonitrile styrene acrylate and polycarbonate, a mixture of polycarbonate and polyethylene terephthalate, and
• the first parts are covered with at least one layer of primer, one base layer and one layer of varnish.
• Figure 1 is a perspective view of a body panel comprising a radome according to the invention
• Figure 2 is a front view of the radome comprising a decorative pattern
• Figure 3 is a sectional view of the radome according to the invention.
• Figure 4 is a front view of a portion of the decorative pattern.
• Figure 5 is a sectional view of a portion of the decorative pattern.
• Figure 1 illustrates a body panel 2, here a front bumper, comprising a protection device configured to protect at least one wave-emitting member.
• the protection device also called radome 4, protects a wave-emitting member (not shown) in position on the front face of a motor vehicle behind the radome 4.
• a wave-emitting member (not shown) in position on the front face of a motor vehicle behind the radome 4.
• a radar placed behind the radome 4 on the front face of a vehicle.
• the radar can be mounted in another position of the vehicle, for example on the rear face, on the side faces or on the roof.
• the number of wave-emitting organs can also vary.
• the radome 4 is at least in part intended to be traversed by the waves emitted by the wave emitter.
• a main body 8 of the radome 4 can be made of a material chosen from PMMA (polymethyl methacrylate), polycarbonate, polypropylene, a polyamide, a copolyester, acrylonitrile butadiene styrene, acrylonitrile. styrene acrylate, styrene acrylonitrile, a mixture of acrylonitrile styrene acrylate and polycarbonate, a mixture of polycarbonate and polyethylene terephthalate.
• PMMA polymethyl methacrylate
• polycarbonate polypropylene
• a polyamide polyamide
• a copolyester acrylonitrile butadiene styrene
• the radome 4 comprises at least one decorative pattern 6.
• This decorative pattern 6 is produced by the presence, on the main body 8 of the radome 4, of an alternation of first parts 10 covered by at least one layer of paint and of seconds. parts 12 not covered by said layer or layers of paint, for example by a paint which does not allow the waves emitted by the wave-emitting member to pass.
• the first parts 10 can be covered with a primer, a base and a varnish not covering the second parts 12.
• the number of paint layers can be different. This does not mean that the second parts 12 are not covered with paint. It is for example possible that the latter are covered with a layer of varnish (preferably transparent to visible light as will be explained later), sharing or not this layer of paint with the first parts 10.
• the face covered by the paint layer (s) may be the internal face 14 of the main body 8 as shown in FIG. 3 or the external face of the radome 4.
• the first parts 10 and the second parts 12 are arranged so as to allow a homogeneous passage of the waves over the whole of the decorative pattern 6.
• the decorative pattern is transparent to these waves as a whole and does not disturb the passage of waves, not generating additional heterogeneity to the signal.
• the first parts 10 are of a width which cannot be less than h / 4 and can be equal to a multiple of l / 4, within the limit of what it is possible to achieve over the length. of the radome 4.
• the selection of a width of the first parts 10 from among the possibilities resulting from the aforementioned formula makes it possible to optimize and homogenize the passage of the waves emitted by a radar.
• the second parts 12 form bands of a width I less than h / 4 separated from each other by the first parts 10.
• the narrowness of the second parts 12 allows radars to be very precise. In other words, and when it will be necessary for a radar, by virtue of its function, to collect data as accurately as possible, the second parts 12 form bands of width less than 1/4, the reduction of the width allowing the radar to gain in precision.
• the width of the second parts 12 is greater than 1/4. This is possible in particular when the function of the radar does not require it to have the finest possible precision. It is even possible that the second parts 12 have a width I equal to or greater than the width L of the first parts 10. It is therefore possible to seek a compromise between the precision of the radar and the aesthetic appearance by dimensioning the second parts 12 of adequately.
• the spacing between two first consecutive parts 10 is constant. This ensures optimal wave passage.
• the first parts 10 and the second parts 12 form rectilinear bands parallel to each other. This makes it possible to facilitate the passage of the waves emitted by a radar. However, it is possible that they form wavy or curved bands (it is then possible to have a constant spacing as described above).
• the first parts 10 and the second parts 12 extend at least partly in a direction perpendicular to a plane in which propagate the waves emitted by a radar.
• the wave-emitting member emits waves propagating in a given plane (traditional radars have unidirectional polarization), conventionally (but not necessarily) in a horizontal plane for a motor vehicle radar.
• the first parts 10 and the second parts 12 are vertical. In the case of non-rectilinear bands, they may extend partly in a direction perpendicular to a plane in which the waves emitted by a radar propagate.
• first parts 10 are all of the same width and all of the second parts 12 are all of the same width. There is therefore repetition of a preferential pattern, for example for the passage of waves. It is alternatively possible to vary the thicknesses of the first parts 10 (while respecting the formula (N * 1) / 4) as well as those of the second parts 12.
• the arrangement of the lines forming the decorative pattern 6 can vary depending on the frequency of emission of the wave-emitting member and the desired result by respecting the formula set out above.
• the realization of the second parts 12 may aim to achieve a backlit pattern as explained above.
• the second parts 12 can therefore also be transparent to visible light (just like the possible layer or layers of paint covering these parts).
• transparent to visible light is understood to mean that it is at least transparent or translucent to any light radiation. exhibiting a wavelength included in the visible spectrum, that is to say between approximately 380 and 780 nm.
• a diffusing light guide arranged so as to diffuse visible light through the second parts 12.
• the light-emitting surface is formed. by a side face of the light guide.
• the light emerges from the diffusing light guide in a substantially radial direction and the distributed light flux is approximately constant at any point on the exit surface of the diffusing part of the diffusing light guide.
• the light diffused by the latter comes from at least one light source which can for example consist of a plurality of light-emitting diodes (LEDs), the light source being able to be deported (ie located outside the zone crossed by the waves and also advantageously outside areas impacted by small shocks, such as “parking” shocks).
• LEDs light-emitting diodes
• the diffusing light guide can be formed by a plurality of optical fibers.
• Optical fibers are plastic. They can also be made of glass. They can be arranged in a sheet. It is possible to obtain radial light output by treating the optical fibers by sandblasting or by laser scraping in order to deteriorate the surface of the latter.
• the attenuation by a sheet of optical fibers of the radar waves was measured with equipment certified for the control of the electromagnetic transparency of radomes. For example, a measurement was made for optical fibers made of PMMA, with a diameter of 500 ⁇ m, and woven with a polyester yarn. The web thus woven, 1 mm thick, was placed between two sheets of polycarbonate 3 mm thick each. In the 76 to 77 GHz band (ACC radar emission range), the attenuation due to the two polycarbonate plates alone (without a layer of optical fibers), measured in transmission ("one way", in one direction only. across all three layers), is 1.39 dB. At these same frequencies, the entire fiber optic web and the two polycarbonate sheets have an attenuation of 0.65 dB.
• the overall attenuation (measured one-way) is below the car manufacturers specification for a radome (eg 1.5dB).
• the measurements show that the fiber optic web is transparent to electromagnetic waves at 77 GHz and that the attenuation is due to the thickness of the two polycarbonate plates.
• the attenuation can be improved by adjusting the thicknesses of the two polycarbonate plates.
• a light guide therefore does not disturb the operation of a radar.
• the diffusing light guide can be made of transparent plastic extruded polycarbonate films having a light transmission greater than or equal to 90% according to the ISO 13468-2 standard, and a refractive index of 1.584 according to the standard. ISO 62.
• the presence of a diffusing light guide makes it possible to illuminate the decorative motif 6. It is possible to replace the above light guide by any light source known to those skilled in the art and being suitable for allow backlighting of the decorative pattern 6.
• radome 4 main body 8 + paint layer (s)
• maximum thickness of radome 4 less than or equal to 6 mm.
• the decorative pattern 6 it is possible to paint the whole of the radome 4 (for example the external face of the radome 4 visible from the outside of a motor vehicle on which the body panel 2 is mounted) then to remove the desired paint layer (s) by laser scraping to form the second parts 12.
• the amount of paint scraped can vary.
• main body 10 first parts 12: second parts 14: internal face of the radome L: width of the first parts 10 I: width of the second parts 12

Landscapes

• Engineering & Computer Science (AREA)
• Remote Sensing (AREA)
• Computer Security & Cryptography (AREA)
• Radar, Positioning & Navigation (AREA)
• Details Of Aerials (AREA)
• Laminated Bodies (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=70154598

Family Applications (1)

Country Status (5)

Families Citing this family (4)

Family Cites Families (7)

• 2019
  • 2019-12-24 FR FR1915533A patent/FR3105608B1/fr active Active
• 2020
  • 2020-08-25 CN CN202010863603.XA patent/CN113036423B/zh active Active
  • 2020-08-25 CN CN202021794271.6U patent/CN213043058U/zh not_active Withdrawn - After Issue
  • 2020-12-23 EP EP20833910.1A patent/EP4082076A1/de active Pending
  • 2020-12-23 US US17/757,853 patent/US12294145B2/en active Active
  • 2020-12-23 WO PCT/EP2020/087739 patent/WO2021130295A1/fr not_active Ceased

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