Decorative radomes, radar systems, and automotive emblems

Abstract

To provide a radome which meets strict wear and resilience requirements needed for external automotive components, is sufficiently radio-transparent to enable minimally attenuated transmission of radio wave frequencies used in radar systems, and is visually appropriate.SOLUTION: A decorative radome comprises: a radio-transmissive substrate 2 having a first surface 3 on a first side and a second surface 4 on a second side; and a first surface radio-transmissive decorative coating 5 configured especially to provide at least one visual feature on the radio-transmissive substrate. Therein, the radio-transmissive decorative coating 5 includes a decorative layer comprising and / or consisting of a metal, or comprising and / or consisting of an alloy containing a metal. A radar system comprises a radio wave transmitter, a radio wave receiver, and the decorative radome of the invention.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001]

[0001] The present invention relates to radomes that include decorative first or second surface coatings. The radomes are particularly useful in automotive applications, and therefore the first or second surface coatings must meet the stringent wear and toughness requirements required for exterior automotive components, while at the same time being sufficiently radio-transparent to allow minimally attenuated transmission of radio frequencies used in RADAR (Radio Detection and Ranging) systems. Furthermore, the radomes must be visually appropriate for their intended purpose. [Background technology]

[0002]

[0002] Radar (RADAR) systems have evolved and become more miniaturized since their development in the early 20th century, and as a result, they are now integrated into a variety of everyday devices. One common use of radar is as driver assistance systems in vehicles. Radar is used in a variety of warning systems, semi-autonomous systems, and autonomous systems within vehicles. Such systems include proximity detection, which can be used for parking assistance, following distance control, collision avoidance, and blind spot detection. Furthermore, radar, in combination with LIDAR (Light Illuminating Detection and Ranging), provides sensing systems that are being developed for autonomous and semi-autonomous vehicles.

[0003]

[0003] Radar systems function on the basis that illuminating radio waves (radar signals) emitted from a transmitter are reflected or scattered by solid objects. These reflected radar waves are then detected by a receiver, typically located close to the transmitter, allowing the radar system to detect the object. Typically, radio waves are reflected when traveling between media with different electrical conductivities. As such, radar systems are particularly effective at detecting conductive materials, such as metals. However, this presents a problem when attempting to develop radar-compatible materials with a metallic appearance.

[0004]

[0004] Because it is undesirable for a radar system to be visible from the outside and because the radar system needs to be protected from environmental damage, the radar system is typically located behind a radome. A radome is a protective cover that is substantially radio-transparent and therefore does not substantially attenuate radio signals. Suitable materials for providing radomes include synthetic polymers (such as plastics) that are electrically insulating. However, the integration of such plastic radomes has been difficult to achieve when a metallic finish is desired. Typical metallic finishes, such as a chrome film on plastic, reflect radio signals and are therefore not suitable for use in radomes.

[0005]

[0005] Traditionally, in automotive applications, radar transmitters and receivers are located at the front of the vehicle, above or on the upper portion of the vehicle's front grille. Market demand for multiple radar-based systems within vehicles, including blind spot detection (BSD), lane change assist (LCA), front / rear cross traffic alert (F / RCTA), autonomous emergency braking (AEB), and adaptive cruise control (ACC), is increasing. This has spurred the need for radar transmitter and sensor placement in many different locations on the vehicle, such as behind the fascia, including the bumper and body panels. Suitable components that can be used on the exterior of an automobile and are radar-compliant are needed.

[0006] Conventional vehicle body components are not ideal radomes for use with radar systems. Metal body panels are not radar-compliant, and therefore radar systems must be positioned behind a radio-transparent substrate, such as a plastic panel. However, many plastics used to make body panels contain fillers, such as talc and carbon, which significantly attenuate radar. This is often due to designs that make the vehicle visible to other radar systems. Even when the substrate is radio-transparent, paint topcoats affect radar transmissions. The metallic components of popular paints and basecoats containing effect pigments also affect the radar transparency of the panel. Furthermore, many of the design constraints for vehicle exterior panels are determined by factors unrelated to, and sometimes contradictory to, optimal radar efficiency. Therefore, it may be desirable to provide radar-compliant trim that constitutes only a small portion of the vehicle's exterior appearance and can act as a radome for the underlying radar system. In some cases, it is desirable for these trim elements to have a metallic appearance.

[0007]

[0007] Techniques and systems have been developed to provide plastic radomes with a metallic appearance, however, all of these techniques and systems require complex layering of substrates sandwiched between layers of metallic appearance.

[0008] One example includes U.S. Patent Application No. US2017 / 0057424 A1, which utilizes nanolayer film stacks that do not contain metal components. Such complex film stacks need to be protected from the external environment because they are susceptible to surface scratches. The use of such complex films, as well as multiple layers to provide film backing and protection, results in significant production costs and time, while also introducing several quality control issues and points of failure. Other radomes utilize complex combinations of films, paints, deposited metals, and complex thermal masking, again resulting in high production times and costs.

[0009] EP 1 560 288 describes an alternative means for providing a radome with a visually metallic component. This document discloses the deposition of a thin film of tin and / or tin alloys onto a transparent substrate. The substrate is then overlaid with a further opaque backing plate that is in effect glued to the front layer. However, the use of adhesive increases production complexity and cost and can result in components susceptible to delamination between the first and second layers. This leads to radio wave attenuation and inaccuracies in the radar system.

[0010]

[0010] Some radomes on the market with a metallic appearance include a first surface protective polymer that is adhered over a decorative coating or film, thereby encapsulating it within the polymer layer. This serves to provide a radome with a uniform thickness and, importantly, protects the decorative coating or film from the external environment. However, such a method is not ideal for providing larger decorative parts, such as vehicle body panels.

[0011]

[0011] Decorative trim and plastic bumpers are not suitable for being formed of multiple plastic layers, as has been proposed for radome badges. Therefore, there is a need to provide automotive panels and trim with a metallic appearance that provide a radio wave transparent decorative coating and are sufficiently robust, as well as a simplified production process.

[0012]

[0012] In the past, different approaches have been taken to further enhance the appearance of coated elements, for example to provide a "satin" appearance to the elements. For example, electroplating has been proposed. Electroplating is a wet process that involves the use of hexavalent chromium, a genotoxic carcinogen. Consequently, this substance has been phased out in regions around the world. For example, the European Union has introduced the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) Under the REACH of Chemicals system, the use of hexavalent chromium has been abolished.

[0013] Hexavalent chromium has been discussed as an alternative, but it offers a relatively inflexible coating system. For example, hexavalent chromium does not allow for the integration of backlighting because it is not transparent, it limits the ability to combine satin and gloss finishes in the same coating on the same part, and it also limits its ability to create different color finishes.

[0014]

[0014] PVD coating methods have been proposed as an alternative. High-end gloss or satin finishes can be achieved without heavy metal wear and without harmful products. However, it is difficult to create coated parts with seamless satin and gloss finishes in the same part. Typically, a PVD satin finish is achieved by a top tint coating with a satin additive, which scatters light from the reflective PVD surface. The satin additive can be adjusted to control the amount of scattering. However, this tint coating is also a wet process, and therefore, it is not easy to create selective satin patterns on a glossy PVD surface using this technique.

[0015] Therefore, what is needed is a method for producing satin patterns on glossy surfaces with minimal processing for a single part, preferably using a coating that allows for backlighting of the satin pattern on the produced surface.

[0016] The above background art discussion is included to explain the context of the present invention and should not be construed as an admission that any of the material referred to was published, known, or part of the common general knowledge as of the priority date of any one of the claims. Summary of the Invention [Means for solving the problem]

[0017]

[0017] The present invention provides a decorative radome comprising a radio wave transparent substrate having a first surface on a first side and a second surface on a second side, and, in particular, a radio wave transparent decorative coating for providing at least one visual feature on the radio wave transparent substrate, wherein the radio wave transparent decorative coating comprises a decorative layer comprising and / or consisting of a metal, or comprising and / or consisting of an alloy containing a metal.

[0018] In a first alternative, the radio wave transparent decorative coating is a first surface radio wave transparent decorative coating located at least partially on a first side, in particular on a first surface, of the radio wave transparent substrate.

[0019]

[0019] In a second alternative, the radio wave-transparent decorative coating is a second surface radio wave-transparent decorative coating at least partially located on the second side, particularly the second surface, of the substrate, and the radio wave-transparent decorative coating is at least partially covered with an overmold layer, particularly the overmold layer comprising a radio wave-transparent polymer and / or located on the side of the radio wave-transparent decorative coating facing away from the substrate.

[0020]

[0020] As a result, the present invention provides a decorative radome having a radio wave transparent decorative coating on the outer surface of the radome in the first alternative, unlike the decorative radome in the second alternative which typically includes a plastic cover layer to protect the decorative coating.

[0021] The simplified radome with the first surface coating allows for more design freedom to provide a wider range of components that can be used in a variety of situations, especially in vehicles. In this regard, such a radome is not limited to a central front position on a vehicle. For example, to provide driver assistance, semi-autonomous, and autonomous capabilities, it is desirable to provide 360° radar coverage of the vehicle. For example, by providing a radar-transparent, metallic-looking trim around the vehicle, the radar system can be positioned in various locations on the vehicle without compromising the vehicle's appearance. Such radar-transparent trim is possible compared to a decorative layer sandwiched between two substrate layers, such as the radome of the second alternative.

[0022]

[0022] In both alternatives, it is proposed that the radio wave transparent substrate comprises at least one first surface structure that is at least partially covered and / or at least partially filled with the radio wave transparent decorative coating, in particular to provide a form-fit connection between the radio wave transparent decorative coating on the one hand and the radio wave transparent substrate on the other hand, or that the radio wave transparent substrate and / or the radio wave transparent decorative coating comprise at least one second surface structure that is at least partially covered and / or at least partially filled with the overmold layer, in particular to provide a form-fit connection between the overmold layer on the one hand and the radio wave transparent substrate and / or the radio wave transparent decorative coating on the other hand.

[0023] The use of such surface structures, particularly those comprising at least one undercut, at least one groove, at least one recess, at least one protrusion, at least one mushroom-shaped element, at least one T-shaped element, and / or at least one anchor element at least partially embedded and / or overmolded in, in particular, the radio-transparent substrate and / or the radio-transparent decorative coating, makes it possible to increase the coherence of the respective elements of the radome, in particular the substrate, coating, and / or layer. In addition to adhesive and / or chemical connections between the elements, the elements are connected to each other in a form-fitting manner. Thus, detachment of the elements from each other during use is much better prevented. Such detachment may result in free spaces that may adversely affect the transparency of the radome and may allow the migration of dust and / or moisture. Such migration may destroy or damage the elements of the radome, for example the decorative coating, and adversely affect the radio-transmission and optical properties such as reflectivity for visible light. Furthermore, it becomes possible to provide larger decorative parts, such as vehicle body panels, for example, where the thickness of the surface protective polymer or overmold can be reduced without adversely affecting the protective properties of the polymer or overmold.

[0024] Another means for increasing the adhesion of the elements in the second alternative is for the radio wave transparent substrate and the radio wave transparent decorative coating to be heated before overmolding, in particular for the radio wave transparent substrate and the decorative coating to be heated to at least 70° C. or at least 80° C. before overmolding. In addition, overmolding can optionally be performed at a barrel nozzle temperature below 300° C. By these means, the bond strength and appearance can be further improved.

[0025] Many thin coating layers are extensible at room temperature, which when applied to plastic substrates, become visibly deformed (e.g., crazing) upon exposure to elevated temperatures. This is believed to be due to the difference in coefficient of thermal expansion (CTE), which is typically on the order of 3-6 times lower for thin coating layers compared to plastic substrates.

[0026] The process of overmolding inherently exposes the thin coating to high temperatures, with nozzle temperatures of up to 300°C or more, as well as the molten plastic resin applied during the second shot of the overmolding process. As such, overmolding a substrate with a thin coating (such as a reflective layer) can cause thermal expansion of the thin coating and substrate, which can cause visual distortion of the thin coating and damage the coating. This would be expected to damage the appearance of the decorative layer and / or coating. However, the present invention allows for the production of a unitary multi-layer article by directly overmolding a decorative layer and / or coating deposited on a substrate, without the need for a heat mask to cover the decorative layer and / or coating. Furthermore, the overmolding process eliminates the need for adhesives to bond the layers within which the decorative layer and / or coating is surrounded.

[0027] Direct overmolding onto a deposited thin coating offers many advantages over current methods of providing such decorative radomes. Deposition of the thin coating by a deposition technique such as physical vapor deposition (PVD) allows for simple, high-throughput production of substrates provided with a decorative layer that reduces the potential for radio signal distortion or attenuation. Furthermore, thin coating deposition by PVD allows for the thickness of the deposited layer to be substantially uniform, which has the advantage of reducing any refraction of the radar signal. Additionally, direct overmolding of the decorative coating encapsulates the coating, thereby protecting it from elemental forces, electrically insulating it, and reducing the potential for water ingress between the substrate and the overmolded layer, a problem found in multi-layer radomes that are bonded by adhesives.

[0028] To help reduce the possibility of visual distortion of the decorative layer and / or coating prior to overmolding, in some embodiments of the present method, the substrate and decorative layer and / or coating are heated prior to overmolding. Preferably, the substrate and decorative layer and / or coating are heated to at least 60 degrees Celsius, or at least 70 degrees Celsius, or at least 75 degrees Celsius, or at least 80 degrees Celsius prior to overmolding. This reduces the rate of temperature change in the decorative layer and / or coating during the second shot of the overmolding process, thereby reducing the degree of thermal expansion during overmolding and helping to reduce the possibility of visual distortion of the decorative layer and / or coating.

[0029] Additionally, reducing the nozzle temperature of the overmolding process, and consequently using a suitable polymer that can flow at the specified nozzle temperature, reduces the likelihood of visual distortion of the decorative layer and / or coating. In some embodiments, the overmolding layer is formed at a barrel nozzle temperature of 300° C. or less, or 280° C. or less, or 250° C. or less, or 245° C. or less during the overmolding process.

[0030] A particularly desirable use of the present invention is to provide badges for the front of vehicles. Typically, such badges are conventionally chrome plated or consist of three-dimensional symbols having a metallic appearance. It would therefore be desirable to attempt to reproduce such badges in a manner that is suitable for use as a radome.

[0031]

[0031] In order to improve the appearance of the radome, in particular to provide such a three-dimensional (3D) visual feature, it is proposed that the radio wave transparent substrate has a relief portion on the second surface and / or the first surface, preferably formed by a recess towards the opposite surface, and / or a raised portion of the radio wave transparent substrate, and in particular that a decorative layer is applied at least partially to the relief portion and / or the raised portion.

[0032]

[0032] In particular, to be able to provide a visual feature having a desired form, for example a logo, a letter or a number, it is proposed that the radio wave transparent substrate be masked so as to limit the area of application of the decorative layer to only a portion of the first or second surface of the radio wave transparent substrate. As a result, in at least some embodiments, the decorative layer is applied to only a portion of the substrate in order to provide the visual feature. This visual feature may be a symbol such as a logo, or or any other desired symbol.

[0033] To be usable as a radome, the decorative coating must minimally attenuate or reflect radio-wave electromagnetic frequencies while substantially absorbing or reflecting electromagnetic radiation in the visible spectrum. This can be achieved by providing one or more electrically insulating or non-conductive thin metal layers, or one or more metal alloy layers.

[0034] To provide a non-conductive alloy containing a metal, it is preferable to include a non-metal. Thus, in some embodiments, the alloy of a metal further includes a non-metal. Preferred non-metals include germanium and / or silicon.

[0035] In embodiments in which the metal alloy includes germanium, the concentration of germanium is preferably at least 25% by weight germanium, or at least 40% by weight germanium, or at least 45% by weight germanium, or at least 50% by weight germanium, or at least 55% by weight germanium, such concentrations providing optimum visual appearance and sufficiently low radio wave attenuation or reflection.

[0036] To minimize radio wave attenuation and reflection, the decorative layer must be provided as a thin film. Thus, in some embodiments, the decorative layer is at most 100 nm thick, or at most 50 nm thick, or at most 40 nm thick, or 10 nm to 40 nm thick, or 20 nm to 40 nm thick, or 25 nm to 35 nm thick, or about 30 nm thick.

[0037]

[0037] A variety of metals can be used for the deposition of the metal layer or for the metal component of the alloy containing the metal. In some embodiments, the metal layer comprises a metal selected from the group of indium or tin. In some embodiments, the alloy includes a metal selected from the group of aluminum, silver, tin, indium, or chromium.

[0038]

[0038] Suitable radio wave transparent alloys may include germanium and aluminum and optionally silicon, or germanium and silicon, or germanium and silver and optionally silicon, or germanium and indium and optionally silicon, or aluminum and germanium and / or silicon, or chromium and germanium and / or silicon.

[0039] The present inventors have determined that when providing a first surface or second surface decorative coating, it is advantageous to control the residual stress of the decorative coating. Without being bound by theory, it has been determined that it is important that the residual stress of the decorative coating be within a desired range that is compatible with the substrate (preferably a synthetic polymer substrate).

[0040]

[0040] It has been confirmed that the first surface or second surface decorative radome exhibits sufficient toughness in durability tests when the radio wave transparent decorative coating has an overall residual stress of -120 MPa or more, -50 MPa or more, or -40 MPa or more. More preferably, the radio wave transparent decorative coating has an overall residual stress of neutral (0 MPa) or tensile (>0 MPa).

[0041] In an embodiment of the decorative coating in which the decorative layer is aluminum and germanium, the net residual stress is preferably greater than or equal to -120 MPa, preferably greater than or equal to -50 MPa. In an embodiment of the radio wave transparent decorative coating in which the decorative layer is chromium and germanium, the net residual stress is greater than or equal to -70 MPa, preferably up to +170 MPa. It is preferable that

[0042]

[0042] The residual stress of the decorative layer can be modified to some extent by modifying the deposition parameters and layer thickness. However, additional layers, such as dielectric layers or hard coat layers, can be provided to further modify the overall residual stress of the decorative coating to within the desired range. These coatings, especially the dielectric layers, can also modify the optical properties and visual appearance of the radio wave transparent decorative coating.

[0043]

[0043] As a result, in some embodiments, the first surface or second surface decorative radome includes multiple layers. In some embodiments, the multiple layers of the decorative coating include a stress control layer and / or a bonding layer. The location of the stress control layer in the multi-layer decorative coating can be any suitable location. However, in some embodiments, the stress control layer is provided between the radio wave transparent substrate and the decorative layer. Alternatively, or additionally, the stress control layer can be provided on the first side of the decorative layer.

[0044] In some embodiments in which the radio wave transparent decorative coating comprises multiple layers, the radio wave transparent decorative coating includes at least one dielectric layer in addition to the decorative layer. In some embodiments, this dielectric layer is provided between the decorative layer and the radio wave transparent substrate. In some further embodiments, the multiple layers of the radio wave transparent decorative coating include at least one decorative layer between at least two dielectric layers. In some embodiments, the radio wave transparent decorative coating includes multiple dielectric layers and / or multiple decorative layers. Preferably, the dielectric layers and decorative layers alternate.

[0045]

[0045] A preferred deposition method that can be used to apply one or more layers of the radio wave transparent decorative coating to the substrate can be selected from any physical vapor deposition system. Such systems can include thermal evaporation, electron beam evaporation (with or without ion beam assistance), sputter deposition, pulsed laser deposition, electrohydrodynamic deposition, cathodic arc deposition, vacuum deposition, and magnetron sputtering, although additionally or alternatively, the decorative layer can also be printed, preferably pad printed, and / or the decorative layer can be colored. Additionally, the surface of the radio wave transparent substrate can first be treated prior to deposition to improve adhesion between the decorative layer and the substrate. In some embodiments, the surface treatment can be selected from plasma discharge, corona discharge, glow discharge, and UV radiation.

[0046] In some embodiments, the radio wave transparent decorative coating can be tailored to achieve a desired stress window by optimizing the deposition parameters of one or more of its layers. These parameters include sputter power, gas pressure, gas dopants (such as nitrogen), and coating thickness. Stress can also be tailored by introducing a thermal stress component through substrate heating or by pre-treating immediately prior to deposition of the layer or radio wave transparent decorative coating.

[0047]

[0047] Means for measuring residual stresses in decorative coatings or individual layers are known in the art. For example, the decorative coating can be placed on a glass slide, and the glass slide can be placed into a stress measurement device (such as a Sigma Physik SIG-500SP) before and after deposition of the layer or coating.

[0048]

[0048] Residual stress can be modified by depositing a layer of material which, when deposited, produces the desired level of stress to compensate for the inherent residual stress of the decorative layer. Suitable materials include SiO x , SiO x N y , CrN x , NbO x , TaO x , and ZrO x In some embodiments including a dielectric layer, the dielectric layer may be SiO x or silicon dioxide. Such a layer is radio-transparent. It can be used to control the overall stress of the radio wave transparent decorative coating and, depending on the positioning of the layers within the radio wave transparent decorative coating, can also affect its visual properties.

[0049]

[0049] It is therefore clear that when the desired optical effect of the decorative layer is required to be changed, concomitant changes are likely to be required in one or more additional layers of the decorative coating to ensure that the overall residual stress of the decorative coating is maintained in the desired window.

[0050]

[0050] Providing a radio wave transparent decorative coating on the first surface of the radome according to the first alternative exposes the radio wave transparent decorative coating to the external environment. This results in the radio wave transparent decorative coating being exposed to various conditions, such as UV light, extreme temperatures, rain, dust, mud, and various chemicals. Furthermore, in applications such as exterior automotive trim, decorative radomes are also exposed to flying objects such as debris. Therefore, the radio wave transparent decorative coating of the radome needs to be sufficiently tough to be used in such environments. To improve the toughness of the radio wave transparent decorative coating, in some embodiments, the radio wave transparent decorative coating can include at least one protective hard coat layer. Typically, this is the top layer of the radio wave transparent decorative coating, thus protecting the underlying layers. However, in some embodiments, an additional capping layer can be present that provides properties such as hydrophobicity, hydrophilicity, oleophobicity, lipophilicity, and oleophobicity, or a combination thereof.

[0051]

[0051] Furthermore, the hard coat layer can function as a tie layer or a stress control layer within the multilayer radio wave transparent decorative coating. As a result, in some embodiments, the radio wave transparent decorative coating includes a hard coat layer between the decorative layer and the radio wave transparent substrate. Preferably, the radio wave transparent decorative coating includes a hard coat layer provided on the first or second surface of the radio wave transparent substrate. In some embodiments, particularly the first alternative, the hard coat layer is between the decorative coating and the radio wave transparent substrate (although it may not be in direct contact with the radio wave transparent substrate).

[0052]

[0052] Without being bound by theory, the hard coat layer likely improves bonding of subsequent layers (such as decorative layers) to the underlying layer or radio wave transparent substrate and helps control differential stresses between layers and overall residual stress in the radio wave transparent decorative coating.

[0053]

[0053] An additional layer may be at the interface between the hardcoat layer and the decorative layer applied to the first or second surface of the radio wave transparent substrate. In some embodiments, a dielectric layer is provided between the decorative layer and the protective hardcoat.

[0054] In a further embodiment, at least two hard coat layers are provided, preferably a first hard coat layer located between the substrate and a second hard coat layer, the second hard coat layer comprising at least one, preferably laser-etched, opening and / or recess. The recess makes it possible to etch into the first hard coat layer, in particular to provide a "satin" appearance, while not changing the optical properties of the remainder of the first hard coat. For this purpose, the first hard coat layer comprises at least one etched surface, in particular by laser etching, in particular in the area of the opening and / or recess of the first hard coat.

[0055]

[0055] To further enhance the visual appearance, the second hard coat layer may be opaque and / or reflective to visible light, and / or the first and / or second hard coat layers are at least partially coated with at least one translucent and / or reflective optical coating for visible light.

[0056]

[0056] Suitable materials for providing the hard coat layer are known in the art, for example, the hard coat layer may include one or more abrasion-resistant layers comprising a material selected from the group consisting of organosilicon, acrylic, urethane, melamine, and amorphous SiOxCyHz.

[0057] As discussed above, it is advantageous to maintain the residual stress of the radio wave transparent decorative coating within an optimal range of -120 MPa or greater, or -70 MPa or greater, or -50 MPa or greater, or -40 MPa or greater. Because a protective hard coat layer can affect the overall residual stress of the decorative coating, in some embodiments, the overall residual stress of the radio wave transparent decorative coating is measured with the protective hard coat. In some embodiments, the overall residual stress is measured without the protective hard coat.

[0058] The radio wave-transparent substrate for the decorative coating can be any suitable substrate that is sufficiently radio wave-transparent and suitable for the intended purpose of the radome. However, preferably, the radio wave-transparent substrate is a synthetic polymer, such as acrylonitrile-ethylene-styrene (AES), acrylonitrile-butadiene-styrene (ABS), acrylonitrile-styrene-acrylate (ASA), polyamide (PA), polybutylene terephthalate (PBT), polycarbonate (PC), polyethylene (PE), polyethylene terephthalate (PET), poly(methyl methacrylate) (PMMA), polyoxymethylene (POM), polypropylene (PP), polyurethane (PU), polyvinyl chloride (PVC), high-flow AES, acrylonitrile-(ethylene-propylene-diene)-styrene (AEPDS), a blend of thermoplastics, or a PC-ABS blend thermoplastic. In some embodiments, the radio wave-transparent substrate is polycarbonate or polypropylene.

[0059]

[0059] Radio waves can be significantly attenuated by water, especially ice, which can condense on the radome in cold conditions. This is particularly prevalent when the radome is used to provide an exterior panel for a vehicle. Therefore, to keep the radome clear of ice and allow for optimal function, some embodiments of the decorative radome of the present invention include a heating element.

[0060]

[0060] In a preferred embodiment, the heating element comprises a resistance wire. The resistance wire can be used to provide Joule heat. When a current flows through the resistance wire, the temperature of the wire increases, thereby providing heat. The amount of heat generated is proportional to the product of the resistance of the wire and the square of the current. Preferably, the wire is provided or molded into a polymer, particularly an overmolding layer, so that the heating element comprises a circuit that can be molded into the polymer. The polymer can be a separate film, and the heating element is molded into the polymer film. This film can then be provided between the radio wave transparent substrate and the radio wave transparent decorative coating. As a result, the heating element is protected from the environment by the radio wave transparent decorative coating, but is close to the surface to provide rapid ice removal.

[0061] Like the radio wave transparent substrate, the polymer providing the membrane for the heating element must be radio wave transparent. As such, the polymer membrane can be made from any compliant polymer, such as those used for radio wave transparent substrates. Thus, polymers for the membrane include acrylonitrile ethylene styrene (AES), acrylonitrile butadiene styrene (ABS), acrylonitrile styrene acrylate (ASA), polyamide (PA), polybutylene terephthalate (PBT), polycarbonate (PC), polyethylene (PE), polyethylene terephthalate (PET), poly(methyl methacrylate) (PMMA), polyoxymethylene (POM), polypropylene (PP), polyurethane (PU), polyvinyl chloride (PVC), high flow AES, acrylonitrile-(ethylene-propylene-diene)-styrene (AEPDS), thermoplastic blends, or PC-ABS blend thermoplastics. In some embodiments, the polymer film is polycarbonate or polypropylene. Indeed, in some embodiments, the heating element is provided on a radio wave transparent substrate.

[0062] To be suitable for use as a radome, the decorative radome of the present invention need not be completely radio-wave transparent and, therefore, may have an acceptable level of radio-wave attenuation. In some specific embodiments, the decorative radome has radio-wave signal attenuation of less than 4 dB (bi-directional), or less than 2 dB (uni-directional) over the signal path, or more preferably, less than 2 dB (bi-directional), or less than 1 dB (uni-directional) over the signal path within the frequency range of 20 to 81 GHz, or 76 to 81 GHz, or 76 to 77 GHz, or at a frequency of about 77 GHz, or about 79 GHz, or about 81 GHz.

[0063]

[0063] To achieve sufficient radio wave transparency, the decorative layer made of a metal or made of an alloy containing a metal must not be substantially electrically conductive. As a result, in some embodiments, the decorative layer is 6 It has a sheet resistance greater than ohms per square (Ω / □).

[0064] The optimum thickness of the radio wave transparent substrate can affect the attenuation of radio waves passing therethrough. Because the decorative radomes of the present invention may be used with radar systems emitting frequencies between 76 and 81 GHz, the optimum thickness of the polycarbonate substrate is a multiple of about 1.15 mm. Thus, in some embodiments, the radio wave transparent substrate has a thickness of about 1.15 mm, 2.3 mm, or 2.45 mm. In some embodiments, particularly for use with vehicles, the radio wave transparent substrate is between 2 mm and 2.6 mm thick. This thickness also provides advantages in weight, cost, formability, and toughness, among other design considerations.

[0065]

[0065] To further improve the appearance, especially the visual characteristics, of the radome, a lighting and / or illumination system is proposed, which comprises at least one light source, preferably comprising at least one LED, at least one laser, and / or at least one light source array, and at least one light guide connected to the light source.

[0066]

[0066] It is an idea of the present invention to use already existing elements and / or layers of the radome as the optical waveguide of the system. Preferably, the optical waveguide is at least partially formed by layers and / or elements located adjacent to and / or in contact with the decorative coating, in particular the radio-transparent substrate, hard coat layer, intermediate layer, and / or overmold layer.

[0067] Additionally or alternatively, the light source is coupled into the optical waveguide in a direction perpendicular to the normal direction of at least a part of the first and / or second surface, in particular the light source is located at least partially at a side edge of the radome, preferably behind a support structure of the radome, such as a brezzel or grille. By these means the light source can be located outside the radio / radar transmission area, as a result of which any adverse effect of the light source on the transparency of the radome is also avoided.

[0068] The present invention further provides a radar system including a radio wave transmitter, a radio wave receiver, and a decorative radome as described herein. The optimum thickness of the radio wave transparent substrate depends on the wavelength of the radio waves emitted from the radio wave transmitter and the dielectric real permittivity of the substrate. Thus, in some embodiments, the thickness of the radio wave transparent substrate of the radome is

[0069]

number

[0070] and λi is a wavelength of the radio wave transmitted from the radio wave transmitter through the substrate. Preferably, the radio wave transmitter transmits radio waves at a frequency of 20 to 81 GHz, or 76 to 81 GHz, or 76 to 77 GHz, or about 77 GHz, or about 79 GHz, or about 81 GHz.

[0071]

[0069] To replicate the metallic finish of many vehicle badges, it is desirable that the decorative layer and / or coating be a reflective layer and / or coating. As a result, in some embodiments, the decorative layer and / or coating is a reflective layer and / or coating that is at least 35% reflective, or at least 45% reflective, or at least 50% reflective, or at least 55% reflective. Because the radome is designed to encapsulate the decorative layer within two polymer layers in the second alternative, it is desirable to measure the reflectivity as viewed from the second surface (i.e., the outer surface of the transparent layer).

[0072] To prevent excessive refraction and distortion of the radio wave signals passing through the radome, it is preferred that the front and back surfaces of the formed radome be parallel or substantially parallel to provide a signal path of uniform thickness for at least a portion of the radome. Thus, in some embodiments, the overmold layer (once in place) provides a third surface that is parallel or substantially parallel to the first surface of the radio wave transparent substrate over at least a portion of the radome, and this portion defines the signal path.

[0073] To allow the decorative layer and / or coating to be viewed, in some embodiments, at least one of either the substrate or the overmold layer is substantially transparent to visible light. Preferably, the radio wave transparent substrate is the layer that is substantially transparent to visible light in the second alternative. One particularly suitable polymer is polycarbonate. Furthermore, to improve the contrast of the decorative layer, adjust the color and reflectivity, and obscure the visibility of the underlying electronics, the layer opposite the transparent layer is substantially opaque. As such, in some embodiments, either the substrate or the overmold layer is substantially opaque to visible light.

[0074]

[0072] The radome of the present invention may further comprise an intermediate layer on at least a portion of the first or second surface of the radio wave transparent substrate. The intermediate layer may serve a decorative role in addition to or in combination with the decorative layer and / or coating. For example, the intermediate layer may be colored, thus adding color to the decorative radome. Thus, in at least some embodiments, the intermediate layer is colored.

[0075] Additionally, in at least some embodiments, the decorative layer and / or coating may act to mask or even mask the application of the decorative layer and / or coating to the radio wave transparent substrate. In such embodiments, the intermediate layer and decorative layer and / or coating are deposited such that the intermediate layer is substantially uncovered or not covered by the decorative layer and / or coating. Such masking may be utilized when shadow masking during deposition of the decorative layer and / or coating is difficult or when adequate detail cannot be achieved by shadow masking. In at least some embodiments, the intermediate layer is used in conjunction with a shadow mask to enable selective application of the decorative layer and / or coating to the radio wave transparent substrate.

[0076] The intermediate layer can be any suitable layer, and in preferred embodiments, the intermediate layer is an ink, dye, oil, or other suitable liquid. The ink can be deposited by a suitable printing method. These can include dye diffusion thermal transfer, wax thermal transfer, indirect dye diffusion thermal transfer, screen printing, inkjet printing, or gravure printing processes such as pad printing. In some embodiments, the intermediate layer is deposited by printing. In some embodiments, the intermediate layer is deposited by pad printing.

[0077]

[0075] In view of the above, it will be understood that references to depositing a decorative layer and / or coating or intermediate layer on the first or second surface of a radio-wave-transparent substrate include deposition onto a coating, layer or film, such as a hard coating, previously deposited on the first or second surface of the radio-wave-transparent substrate (unless expressly stated otherwise).

[0078]

[0076] The hard coat acts as a protective layer against the external environment, reducing physical and chemical damage.

[0077] The intermediate layer can be any suitable layer, and in a preferred embodiment, the intermediate layer is an ink, dye, oil, wax, lubricant, or other suitable liquid. In a preferred embodiment, the intermediate layer is an ink.

[0079]

[0078] Particular embodiments are illustrated by the following figures: It should be understood that the following description is for purposes of illustrating particular embodiments only and is not intended to be limiting with respect to the description. [Brief explanation of the drawings]

[0080] [Figure 1]

[0079] FIG. 1 illustrates an embodiment of a decorative radome of the present invention according to a first alternative, showing that radio waves (long diagonal lines) can pass through the radome while visible light (short diagonal lines) is reflected from the decorative layer. [Figure 2]

[0080] Figure 1 illustrates an embodiment of a decorative radome of the present invention according to a first alternative, including an upper coating that scatters visible light (short diagonal lines), thereby providing a satin appearance. [Figure 2a]

[0081] FIG. 1 illustrates a radome according to the present invention with two hard coat layers to provide a "satin" appearance. [Figure 2b]

[0082] FIG. 2b is a view of a radome including the "satin" feature as shown in FIG. 2a. [Figure 2c]

[0083] FIG. 2B is a view of an alternative radome including a "satin" feature similar to that shown in FIG. 2a. [Figure 3]

[0084] A figure illustrating an embodiment of a decorative radome of the present invention according to a first alternative, which includes an intermediate dielectric layer between the substrate and the decorative layer. [Figure 4]

[0085] FIG. 2 illustrates an embodiment of a decorative radome of the present invention according to a first alternative, including dielectric layers above and below the decorative layer. [Figure 5]

[0086] A figure illustrating an embodiment of a decorative radome of the present invention according to a first alternative, including a multi-stack decorative coating with multiple decorative layers and multiple dielectric layers. [Figure 6]

[0087] FIG. 2 illustrates an embodiment of the decorative radome of the present invention according to a first alternative, including a heating element between the radio wave transparent substrate and the decorative coating. [Figure 7]

[0088] 1 illustrates a radar system including a radio transmitter / receiver and a radome according to the present invention according to a first alternative; [Figure 8]

[0089] FIG. 1 illustrates the measured change in attenuation of 77 GHz radio waves through uncoated polycarbonate as a result of changes in polycarbonate thickness. [Figure 9]

[0090] 1A-B illustrate the average attenuation of radio waves between 76-77 GHz and 79-81 GHz across 2 mm (A) and 2.3 mm (B) thick polycarbonate. [Figure 10]

[0091] FIG. 1 illustrates the measured change in attenuation of 77 GHz radio waves through coated polycarbonate compared to uncoated polycarbonate as a result of changes in polycarbonate thickness. [Figure 11]

[0092] FIG. 1 illustrates the measured CIELAB color of gloss-coated and satin-coated radomes. [Figure 12]

[0093] FIG. 10 is a flow diagram of an example of a method for manufacturing a radome according to a second alternative of the present invention. [Figure 13]

[0094] FIG. 10 is a cross-sectional view of an example of a radome according to a second alternative of the present invention. [Figure 14]

[0095] FIG. 10 is a cross-sectional view of an example of a radome according to a second alternative of the present invention, including an intermediate layer. [Figure 15]

[0096] FIG. 10 is a cross-sectional view of an example radome according to a second alternative of the present invention showing first and second surface structures for arriving at a form-fit connection. [Figure 16]

[0097] 1 is a schematic cross-sectional exploded view of an illuminated radome according to the present invention; [Figure 17]

[0098] FIG. 10 is a cross-sectional view of an example of a radome according to a second alternative of the present invention, including an illumination system. [Figure 18]

[0099] FIG. 18 is a view of a radome illuminated by an illumination system such as that shown in FIG. 17.

[0081]

[0100] DETAILED DESCRIPTION OF THE INVENTION

[0082]

[0101] Throughout this specification, references to layers will be made in relation to the plastic substrate and in relation to each other. Accordingly, the following terms are used to define the spatial relationship of the coating in relation to the substrate and the spatial relationship of the layers within the coating to each other.

[0083]

[0102] A "first side" is to be understood as the side of a substrate, coating, or particular layer that, in use, faces away from a radio wave transmitting or receiving device. As such, the first side is the side that faces towards the external environment. In the particular context of a vehicle, this is the side that is visible from the outside of the vehicle.

[0084]

[0103] The "second side" is to be understood as the side opposite the first side. In the context of use, this is the side facing the radio wave transmitting or receiving device. Typically, the second side is not visible when the radome is in use.

[0085]

[0104] "First surface" shall be understood to refer to the surface on a first side of a substrate, coating, or designated layer.

[0105] "Second surface" shall be understood to refer to the surface on the second side of the substrate, coating, or specified layer.

[0086]

[0106] The term "reflective" (without modifiers such as "radio wave") refers to the reflection of visible light, typically within nanometer wavelengths and the frequency range of 400-800 THz.

[0107] References to radio waves throughout this specification typically refer to frequencies between 10 MHz and 3000 GHz. In preferred embodiments, and in connection with automobiles, the frequencies are typically between 1000 MHz and 100 GHz. In some specific embodiments related to radomes for vehicles, the frequencies are between 21 GHz and 81 GHz, or about 24 GHz to about 79 GHz, or about 77 GHz to about 79 GHz, or about 24 GHz, about 77 GHz, or about 79 GHz. In this context, the use of about refers to the specified band (e.g., This specification does not exclude an explicit limitation to a frequency band (e.g., 24 GHz), but anticipates typical bandwidths used in applications such as automotive radar systems. These bandwidths are known in the art; see, for example, Hasch et al., "Millimeter-Wave Technology for Automotive Radar Sensors in the 77 GHz Frequency Band," IEEE Transactions on Microwave Theory and Techniques (Volume: 60, Issue: 3, March 2012).

[0087]

[0108] The terms "transparent" and "opaque," when used without a modifier (such as "radio" or "radar"), refer to visually transparent or opaque, and thus are references to transmission or absorption of visible light as defined above.

[0088]

[0109] As discussed above, the decorative radome of the present invention comprises a first surface or second surface coating, which is a coating on a first side and in contact with a first surface of a substrate, or on a second side and in contact with a second surface of a substrate. The first surface or second surface coating may include multiple "stacked" layers, each layer having a first surface and a second surface, with the first surface of one layer abutting the second surface of an overlying layer, which itself has a first surface. Consequently, the use of the terms "first side," "second side," "first surface," and "second surface" should be read and interpreted in the relative context in which they are used.

[0089]

[0110] The decorative radome (1) according to the present invention is illustrated in Figures 1 to 6 and includes a radio wave transparent substrate (2) having a first surface (3) on a first side and a second surface (4) on a second side, and a radio wave transparent decorative coating (5) on the first surface (3) of the radio wave transparent substrate (2), the radio wave transparent decorative coating (5) including a decorative layer (6) made of a metal or an alloy containing a metal.

[0090]

[0111] As illustrated in Figures 1 and 2, the radome of the present invention allows radio waves to pass through the radome (long dashed line) while some visible light (short dashed line) is reflected from the decorative layer (6) so that the appearance of the radome (1) is colored or reflective.

[0091] Radio wave transparent substrate

[0112] The radome (1) of the present invention is for use in the intended radio wave path of a transmitter and / or receiver for a wireless communication or radar system, and as such, the design of the radome may be dictated by its intended application. As a result, the selection of a material for the radio wave transparent substrate (2) will be dictated in part by design considerations, such as robustness, formability, resistance to extreme temperatures, and cost, and is not based solely on the degree of radio transparency. As such, the radio wave transparent substrate (2) may be any substrate that attenuates desired radio wave frequencies at an acceptable level for the desired application. As will be understood, all substrates will attenuate and reflect radio waves to some extent.

[0092]

[0113] However, in some embodiments of the present invention, the substrate is a polymer, preferably a synthetic polymer. As understood in the art, radio wave transparent substrates typically resist electrical conductivity (i.e., are insulating or dielectric). Suitable polymers for the substrate (2) include acrylonitrile ethylene styrene (AES), acrylonitrile butadiene styrene (ABS), acrylonitrile styrene acrylate (ASA), polyamide (PA), polybutylene terephthalate (PBT), polycarbonate (PC), polyethylene (PE), polyethylene terephthalate (PET), poly(methyl methacrylate) (PMMA), polyoxymethylene (P), and the like. Examples of suitable thermoplastics include, but are not limited to, polypropylene (PP), polyurethane (PU), polyvinyl chloride (PVC), high flow AES, acrylonitrile-(ethylene-propylene-diene)-styrene (AEPDS), a blend of thermoplastics, or a PC-ABS blend thermoplastic. In some embodiments, the radio wave transparent substrate (2) will be formed of polycarbonate or polypropylene.

[0093] decorative coating

[0114] The decorative layer (6) of the decorative coating (5) is preferably a reflective layer and comprises any suitable metal or metal-containing alloy that provides the desired reflectivity or appearance while being radio-transparent. In some embodiments, the metal forming the decorative layer (6) is a transition metal. In some embodiments, the metal forming the decorative layer (6) is indium or tin.

[0094]

[0115] In some embodiments in which the decorative layer (6) is an alloy containing a metal, the alloy contains a metal selected from the group consisting of aluminum, tin, indium, or chromium. In some embodiments, the decorative layer (6) contains a non-metal. The non-metal includes silicon, boron, germanium, arsenic, antimony, and / or tellurium. In particularly preferred embodiments, the non-metal is germanium or silicon. In the most preferred embodiment, the non-metal is germanium. Suitable non-metal / metal alloys include germanium and aluminum and / or silicon, or germanium and silicon, or germanium and silver and optionally silicon, or germanium and indium and optionally silicon, or chromium and germanium and / or silicon. In some distinct embodiments, the alloy is not silicon and aluminum.

[0095]

[0116] In embodiments in which the metal alloy includes germanium, the concentration of germanium may be at least 25% by weight germanium, or at least 40% by weight germanium, or at least 45% by weight germanium, or at least 50% by weight germanium, or at least 55% by weight germanium.

[0096]

[0117] Methods for providing thin film layers, such as the decorative layer (6) made of a metal or an alloy containing a metal, are known in the art. Preferably, however, the decorative layer (6) is deposited by physical vapor deposition (PVD). Suitable PVD methods include magnetron sputtering and evaporation, which may be resistive thermal evaporation or electron beam evaporation. In some embodiments, the decorative layer (6) is deposited by magnetron sputtering.

[0097]

[0118] In some embodiments, the decorative coating (5) includes multiple layers, with the decorative layer (6) abutting one or more additional layers. In some embodiments, the multiple layers of the decorative coating (5) include a bonding layer. Typically, the bonding layer will be in direct contact with the substrate and thus form the first layer in the multilayer stack. For example, a hard coat layer (7) can be provided on the first surface (3) of the substrate (2) prior to the addition of additional layers in the decorative coating. Such a hard coat layer (7) can improve the bonding strength of the decorative layer (6) to the substrate (2), thereby reducing the likelihood of delamination of the coating (5) from the substrate (2). The hard coat (7) can also affect the overall residual stress of the radio wave-transparent decorative layer (5) and, as such, can act, at least in part, as a stress control layer.

[0098]

[0119] In some embodiments, the radio wave transparent decorative coating (5) includes a stress control layer that may be below or above the radio wave transparent decorative layer (6). As illustrated in Figures 1, 2, 4, 5 and 6, the stress control layer (8) is on the first side (preferably the first surface) of the decorative layer (6).

[0099]

[0120] In some embodiments, as illustrated in Figures 4 and 5, the radio wave transparent decorative coating may include a stress control layer (8) below the decorative layer (6). In these embodiments, the stress control layer (8) is between the radio wave transparent substrate and the decorative layer (6). The stress control layer may be positioned above the hard coat (7) on the first surface (3) of the radio wave transparent substrate (2) and below the decorative layer (6).

[0100]

[0121] In some embodiments, the multiple layers of the radio wave transparent decorative coating (5) include at least one dielectric layer, which in the illustrated embodiment is a stress control layer (8). However, the dielectric layer may also modify the visual characteristics of the decorative coating (5). This is particularly relevant in embodiments with multiple decorative layers (6) or a top dielectric layer (8) (Figures 1, 2, 4, 5, and 6). Suitable dielectrics for thin film deposition are known in the art and include oxides such as hafnium dioxide (HfO), aluminum oxide (AlO), zirconium dioxide (ZrO), titanium dioxide (TiO), and silicon dioxide (SiO). In a preferred embodiment, the dielectric layer is silicon dioxide (SiO).

[0101]

[0122] In some embodiments, the radio wave transparent decorative coating (5) comprises at least one layer (6) of a metal or metal-containing alloy between at least two dielectric layers (8) (see Figures 4 and 5). Additionally, in the embodiment illustrated in Figure 5, the decorative coating (5) comprises two decorative layers (6) sandwiched between alternating dielectric layers (8). These multi-layer stacks allow for tuning of the radio wave transparent decorative coating (5), including its color and residual stress.

[0102]

[0123] Different visual appearances may be achievable by providing a radio wave transparent decorative coating that includes multiple stacked layers. Examples of possible multi-layer stacks include: SiO2:AlGe:SiO2:AlGe:SiO2 SiO2:CrGe:SiO2:CrGe:SiO2 AlGe:SiO2:AlGe:SiO2 CrGe:SiO2:CrGe:SiO2 ·AlSi:SiO2:AlSi:SiO2

[0103]

[0124] Such an optical stack may include a stress control layer to optimize the residual stress of the radio wave transparent decorative coating (5) within a desired window. Preferably, this stress window is greater than or equal to -120 MPa, or greater than or equal to -70 MPa, or greater than or equal to -50 MPa, or greater than or equal to -40 MPa. Suitable materials for controlling stress include a dielectric layer, such as an additional silicon dioxide layer, which can be adjusted (e.g., by changing the thickness and deposition conditions) to provide the desired stress range without changing the visual appearance of the decorative coating.

[0104] Protective hard coat

[0125] The essential function of a radome is to provide protection for radar equipment from the environment. As such, radomes are susceptible to degradation, wear, and damage. This exposure is further amplified when the radome is located at the front of a vehicle where it is routinely exposed to relatively high speeds, abrasives, flying objects, and chemicals used in cleaning.

[0105]

[0126] As a result, in a preferred embodiment of the present invention, the outermost layer of the decorative coating 5 is a protective hardcoat 9. In this regard, a coating that is said to be a "hardcoat" is one that is harder and tougher (e.g., chemically tougher) than the underlying layers, thereby increasing the abrasion resistance, resistance to environmental damage, or chemical resistance of the radome.

[0106]

[0127] As discussed above, the intermediate layer of the decorative coating (5) may also include a hardcoat layer (7), which may be of the same material as the protective hardcoat (9) or a different material.

[0107]

[0128] In some embodiments, the hard coat increases the abrasion resistance of the surface, which can be measured through standard tests such as ASTM F735 "Standard Test Method for Abrasion Resistance of Transparent Plastics and Coatings Using the Vibrating Sand Method," ASTM D4060 "Standard Test Method for Abrasion Resistance of Organic Coatings" by a Taber Abrasion Tester, or by using the known steel wool test.

[0108]

[0129] A requirement of many automotive exterior components, such as radomes, is that they be "chemically resistant," which refers to their ability to withstand exposure to common solvents such as diesel, petroleum, battery acid, brake fluid, antifreeze, acetone, alcohol, automatic transmission fluid, hydraulic fluid, and ammonia-based window cleaners. In this regard, a hardcoat (7, 9) ideally provides such chemical resistance to at least the first surface of the radome.

[0109]

[0130] The hard coat (7, 9) is preferably formed from one or more abrasion-resistant layers and may include a primer layer that firmly bonds to the underlying layer to form a favorable surface for a subsequent overcoat. The primer layer may be made of any suitable material, for example, an organic resin such as an acrylic polymer, a copolymer of an acrylic monomer and methacryloxysilane, or a copolymer of a methacrylic monomer and an acrylic monomer having a benzotriazole group or a benzophenone group. These organic resins may be used alone or in combination of two or more.

[0110]

[0131] The hard coat layer (7, 9) is preferably made of organic silicon, acrylic, urethane, melamine, or amorphous SiO x C y H z It is formed from one or more materials selected from the following group.

[0111]

[0132] Commercially available hard coatings include Momentive products: PHC-587B, PHC-587C2, PHCXH100P, AS4700F, UVHC 5000 (UV cured), and a two-part product containing a primer coat of PR660 (SDC Technologies) followed by a coating of MP101 (SDC Technologies).

[0112]

[0133] Most preferably, the hard coat layer (7, 9) is an organosilicon layer due to its excellent abrasion resistance and compatibility with physical vapor deposition films. For example, hard coat layers comprising organosilicon polymers may be prepared using the following compounds: methyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxyethoxysilane, methyltriacetoxysilane, methyltrippropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltracetoxysilane, vinyltrimethoxyethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, gamma-chloropropyltrimethoxysilane, gamma-chloropropyltriethoxysilane, gamma-chloropropyltripropoxysilane, 3 trialkoxysilanes or triacyloxysilanes such as 3,3-trifluoropropyltrimethoxysilane, gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltriethoxysilane, gamma-(beta-glycidoxyethoxy)propyltrimethoxysilane, beta-(26,4-epoxycyclohexyl)ethyltrimethoxysilane, beta-(26,4-epoxycyclohexyl)ethyltriethoxysilane, gamma-methacryloxypropyltrimethyoxysilane, gamma-aminopropyltrimethoxysilane, gamma-aminopropyltriethoxysilane, gamma-meraptopropyltrimethoxysilane, gamma-mercaptopropyltriethoxysilane, N-beta(aminoethyl)-gamma-aminopropyltrimethoxysilane, beta-cyanoethyltriethoxysilane, and the like; and a compound selected from a dialkoxysilane or diacyloxysilane such as dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldiethoxysilane, phenylmethyldiethoxysilane, gamma-glycidoxypropylmethyldimethoxysilane, gamma-glycidoxypropylmethyldiethoxysilane, gamma-glycidoxypropylphenyldimethoxysilane, gamma-glycidoxypropylphenyldiethoxysilane, gamma-chloropropylmethyldimethoxysilane, gamma-chloropropylmethyldiethoxysilane, dimethyldiacetoxysilane, gamma-methacryloxypropylmethyldimethoxysilane, gamma-methacryloxypropylmethyldiethoxysilane, gamma-mercaptopropylmethyldimethoxysilane, gamma-mercaptopropylmethyldiethoxysilane, gamma-aminopropylmethyldimethoxysilane, gamma-aminopropylmethyldiethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, and the like.

[0113]

[0134] The hard coat layers (7, 9) can be applied by dip coating in a liquid followed by solvent evaporation, or by plasma-enhanced chemical vapor deposition (PECVD), flow coating, or spray coating with a suitable monomer. To improve the abrasion resistance of the hard coats (7, 9), subsequent coats of hard coat can be added, preferably within 48 hours, to avoid aging and contamination of the previous coat.

[0114]

[0135] The thickness of the hard coat layers (7, 9) is preferably selected to help provide adequate abrasion resistance or to improve bonding of subsequent layers to the radio wave transparent substrate (2). Suitable abrasion resistance is determined by the required application and user needs. In some applications, adequate abrasion resistance can be considered a Bayer abrasion rating of 5 against an uncoated radio wave transparent substrate (2) (such as polycarbonate), or alternatively, a Taber abrasion test with a delta haze of less than 15% (% haze measured according to ASTM D1003) after 500 cycles with a 500 g load and a CS10F wheel. If these requirements are met, when organosilicon is used as the hard coat layers (7, 9), the thickness of the hard coat is preferably at least 1 μm thick on average and / or has a maximum thickness of 25 μm thick. In some embodiments, the thickness of the hard coat layer (7) provided on the first surface (3) is between 1 μm and 15 μm. In some embodiments, the thickness of the hard coat layer (7) provided on the first surface (3) is 2 μm to 10 μm, or 2 μm to 9 μm. In some embodiments, the thickness of the protective hard coat layer (9) is 5 μm to 25 μm. In some embodiments, the thickness of the protective hard coat layer (9) is 8 μm to 20 μm, or 8 μm to 16 μm.

[0115]

[0136] The protective hard coat (9) may also modify the appearance of the decorative layer (6). As illustrated in Figure 2, the protective hard coat (9) may contain additives to scatter reflected visible light. As a result, the decorative layer (6) has a "satin" appearance on the exterior.

[0116]

[0137] However, the present invention is not limited to providing a uniform satin appearance on a complete decorative coating. The present invention makes it possible to provide visual features, particularly satin graphics or patterns in the decorative coating, where only a portion, e.g., a logo, is provided at least in part by a PVD coating method on a substrate, particularly substrate 2. In the embodiment shown in Figure 2a, a radome (1') is shown comprising a substrate (2') and a decorative coating (5') providing such a satin pattern.

[0117]

[0138] The decorative coating (5') comprises a different layer structure including a first hard coat (9a'), a second hard coat (9b') and a further coating layer (10').

[0118]

[0139] The satin graphic is provided by first applying a hard coat layer (9a') to the substrate (2'), particularly a plastic and / or polycarbonate substrate. The hard coat layer (9a') can be provided by dip coating using a polysiloxane hard coat, for example, PHC-587B from Momentive. After dip coating, the material is flashed off and cured. In this way, a hard coat layer (9a') having a thickness of, for example, more than 3 μm can be provided.

[0119]

[0140] In a further step, a second hard coat layer (9b') is provided. The hard coat layer (9b') can be provided by a PVD coating process using a batch coating vacuum chamber. Preferably, the hard coat layer (9b') is opaque to visible light. For example, a hard coat layer with silica and metal can be provided to create a highly reflective surface.

[0120]

[0141] In the next step, recesses (10') are created to provide the desired pattern / graphic. These recesses (10') are created by laser etching from the second hard coat layer (9b') in selected areas. As part of the process, the laser also etches the first hard coat layer (9a') below the second hard coat layer (9b') in the area of the recess. For example, a laser marking system operating at a 1064 nm wavelength can be used for this etching process. For example, the laser can use a speed of 500-1200 mm / s with a laser pulse frequency of 30-80 kHz.

[0121]

[0142] In a further step, an optical coating (11') is produced which is preferably semi-transparent to visible light and covers the hard coat layer (9b') and the etched hard coat layer (9a'), especially in the area of the recess (10').

[0122]

[0143] Due to the etching of the hard coat layer (9a') in the area of the recess (10'), light falling on the hard coat layer (9a') in this area is scattered. This creates a satin effect in this area. When the hard coat layer (9b') is applied and not etched by the laser, the preferably opaque hard coat layer (9b') remains highly reflective.

[0123]

[0144] It is therefore possible to create patterns that combine highly reflective and satin areas to provide the desired visual features. Examples of visual features in the form of logos and patterns are shown in Figures 2b and 2c. This area (10') provides a satin reflective effect, while the remaining area (12') retains the highly reflective properties of the coating (11').

[0124]

[0145] An additional advantage of the decorative coating shown in Figures 2a-2c is that it allows for backlighting of visual features. As shown in Figure 2a, an illumination source 14' can be located on the side of the radome 1' where the radio / radar transceiver 13' is located. When the radome 1' is illuminated by the light source 14', for example, with a respective LED array for the observer 16', the following visual effect is achieved: In the area of the recess 10', the hard coat layer 9a' is illuminated due to the scattering effect of the surface in this area. However, due to the hard coat layer 11' in area 12', the light is attenuated, and these areas are invisible or nearly invisible to the observer 16', but remain reflective to light pouring onto them from the side of the observer 16'. Thus, various aesthetic effects can be realized for product styling purposes through background illumination. If the hard coat layer (9b') is opaque, any light escaping outside the area of the recess (10') is avoided and no double imaging occurs from reflection of light within this area on different surfaces, in particular the surfaces of the hard coat layers (9a') and (9b').

[0125]

[0146] By varying the laser parameters such as power, path, speed, and frequency, different types of etching of the first hard coat layer (9a') in the area of the recess (10') can be achieved. For example, it is possible to vary the degree of scattering and / or diffusion of the light falling on or through the area (10'). Thus, different satin finishes can be achieved.

[0126]

[0147] In contrast to satin generation, which is a method known in the prior art, a robust method is provided for providing a satin surface in combination with a reflective surface.

[0148] Although described with the help of the first alternative of the radome of the present invention, the use of the previously described decorative coating comprising hard coat layers (9a') and (9b') can also be applied to the second alternative of the radome of the present invention, in which case layer (11') can be replaced by an overmolded layer and / or the second hard coat layer (9') does not need to be highly reflective and / or opaque.

[0127]

[0149] Further coatings to those discussed above may be applied to the first surface of the decorative coating (5) to modify the surface properties of the radome (1). For example, a cap layer may also be provided by a material having properties including hydrophobic, hydrophilic, oleophobic, lipophilic, and oil-repellent properties, or a combination thereof.

[0128] Coating residual stress

[0150] The importance of residual stress, the use of interfacial layers in controlling residual stress, and the determination of residual stress parameters are explained in WO 2011 / 075796 and U.S. Pat. No. 9,176,256 B2, each entitled "PLASTIC AUTOMOTIVE MIRRORS," each of which is incorporated herein by reference in its entirety for all purposes.

[0129]

[0151] Highly stressed interfaces between layers of the decorative coating (5) and between the decorative coating (5) and the substrate (2) should ideally be avoided to prevent high stress areas that could become points of failure. For example, a compressive layer pulls in one direction against a tensile layer pulling in the opposite direction, creating an interfacial stress. It has been discovered that by controlling (reducing) this interfacial stress, the toughness of the decorative coating (5) can be improved.

[0130]

[0152] Therefore, the inventors have found that it is preferable to control the internal stress parameters of the decorative coating (5) so that the differential stress is minimized. The inventors have found that the internal stress parameters of the decorative coating (5) are controlled so that the net residual stress is greater than -120 MPa. It has further been found that it is preferable to control the net residual stress meter. In some embodiments, the net residual stress is greater than -70 MPa, or greater than -50 MPa, or greater than -40 MPa. In some preferred embodiments, the net residual stress is neutral or tensile (i.e., greater than 0 MPa). In particular, for decorative coatings (5) comprising a decorative layer (6) of aluminum and germanium, the net residual stress is greater than -120 MPa, or greater than -50 MPa, or greater than -40 MPa. In embodiments of decorative coatings (5) in which the decorative layer (6) is chromium and germanium, it is preferred that the net residual stress is greater than -70 MPa, preferably up to +170 MPa.

[0131]

[0153] With respect to being able to control internal stress parameters, ideally the stress throughout the coating system would be controlled in both magnitude and mode. The term "residual stress" shall be taken to mean the combined stress of the multiple layers that form the decorative coating (5), which may or may not include a protective hard coat (9). In a preferred embodiment, the residual stress is measured or calculated in conjunction with the protective hard coat (9).

[0132]

[0154] In order to manufacture a decorative radome in a manner that allows for control of the measured residual stress in the decorative coating (5), the inventors have determined that it is beneficial to know the stress ranges of the individual layers so that when combined, they result in the desired measured residual stress.

[0133]

[0155] The concept of the second surface decorative coating according to the second alternative of the invention is explained with the help of FIGS.

[0156] Specifically, a method for producing a decorative radome according to the second alternative is illustrated in Figure 12 and includes the step of preparing or providing (102) a (radio wave transparent) substrate. The radio wave transparent substrate will have a first surface (122) and a second surface (123, see Figure 13). The method further includes applying (105) a decorative layer and / or coating (124) to a portion of the second surface (123) of the substrate (121), preferably the portion including the mitigation portion (125), where the decorative layer and / or coating (124) comprises a metal or an alloy containing a metal and a non-metal. Subsequently, the method further includes overmolding (107) at least the decorative layer and / or coating (124) with a radio wave transparent polymer to provide an overmolding layer (126).

[0134]

[0157] The term "second surface," as used in the context of the following description, refers to a surface onto which a decorative layer (124) may be applied and overmolded. The term "first surface" is used in contrast to the second surface. In one form, the radio wave transparent substrate (121) is substantially transparent as formed and will provide the front-most surface of the radome in use. In this context, the term "first surface" refers to the forward-most surface of the substrate (121) when viewed. As such, and in the context of an automobile badge, the first surface (122) in the following description is the front surface of the radio wave transparent substrate (121) of the badge when viewed from the front of the automobile.

[0135]

[0158] Although described with respect to the second alternative of the present invention, the measures described in the following paragraphs with respect to providing the substrate, intermediate layer, hard coat, shadow masking, decorative layer and / or coating, and / or surface coating, and with respect to heating, may also be used, at least in part, for a radome according to the first alternative of the present invention.

[0136]

[0159] 1- Substrate provision / preparation

[0160] The radio wave transparent substrate (121) can be provided by any desired method. In some embodiments, the substrate (121) is injection molded to form the desired shape. In some embodiments, the substrate (121) may be received already formed. Preferably, the substrate (121) includes a relief portion (125) that defines a three-dimensional visual feature on the second surface (123) of the substrate (121). The relief portion (125) may be provided by a recess toward the first surface (122) of the substrate (121).

[0137]

[0161] The substrate (121) and overmold layer (126) can be formed of any suitable material, but are preferably plastic. As understood in the art, radio wave transparent substrates typically resist electrical conductivity (i.e., are insulating or dielectric). Suitable polymers for the substrate (121) or overmold layer (126) include acrylonitrile-ethylene-styrene (AES), acrylonitrile-butadiene-styrene (ABS), polycarbonate (PC), high-flow AES, acrylonitrile-(ethylene-propylene-diene)-styrene (AEPDS), blends of thermoplastics, or PC-ABS blend thermoplastics. In some embodiments, the substrate (121) will be formed of polycarbonate.

[0138]

[0162] Importantly, either the substrate (121) or the overmold layer (126) is substantially transparent. This allows the decorative layer and / or coating (124) to be seen through the transparent layer. Preferably, the other layer is substantially opaque to visible light. The opaque layer can mask equipment located behind the radome and modify or improve the visual aspects of the decorative layer and / or coating (124). For example, it can enhance the color or reflectivity of the decorative layer and / or coating (124) by minimizing light transmission through the decorative layer and / or coating (124). In use, for example, when a radome according to the present invention (such as a radome produced by the method of the present invention) is installed as an automobile badge, the transparent layer is the outermost (front) layer. In a preferred embodiment, the radio wave-transmitting substrate (121) is transparent and the overmold layer (126) is opaque.

[0139]

[0163] 2- Applying the intermediate layer

[0164] In some embodiments, the method includes providing an intermediate layer (129) on at least a portion of the second surface of the radio wave transparent substrate (121). In some embodiments, the intermediate layer (129) is applied before the application of the decorative layer and / or coating (124), and may be applied before or following the deposition of the second surface coating (128) (in embodiments where this is applied).

[0140]

[0165] The intermediate layer (129) can be used to affect the appearance of the decorative radome produced by the method of the present invention. The intermediate layer (129) can be a colored layer that applies a visible color to the decorative radome. The intermediate layer (129) can also be a masking layer (which can be removable before overmolding or can be clear and remain on the decorative radome after production) that helps prevent the application of the decorative layer and / or coating (124) to undesired portions of the radio wave transparent substrate (121). In such embodiments, the intermediate layer (129) is substantially uncovered or uncovered by the decorative layer and / or coating (124) when the radome is completed. Such masking can be utilized when shadow masking during application of the decorative layer and / or coating (124) is difficult or when adequate detail cannot be achieved by shadow masking. In some embodiments, the intermediate layer (129) can be an oil, liquid, or ink mask, such as Fomblin™, Krytox™, SpeedMask™.

[0141]

[0166] In a preferred embodiment, the intermediate layer (129) is applied by printing. In some embodiments, the intermediate layer can withstand temperatures of 150°C, 175°C, 200°C, 220°C, 250°C, 275°C, or 300°C or greater for a minimum of 5, 10, 20, 30, 40, or 50 seconds, or 1, 1.5, or 2 minutes.

[0142]

[0167] The intermediate layer (129) can be any suitable layer, and in preferred embodiments, the intermediate layer (129) is an ink, dye, oil, wax, lubricant, or other suitable liquid or colored film. In some embodiments, the intermediate layer is an ink. The ink can be deposited by any suitable method. In some embodiments, the intermediate layer (129) is printed. Printing methods can include dye diffusion thermal transfer, wax thermal transfer, indirect dye diffusion thermal transfer, screen printing, inkjet printing, or gravure printing processes such as pad printing. In some embodiments, the intermediate layer (129) is applied by pad printing.

[0143]

[0168] Suitable methods for printing onto the radio wave transparent substrate (121) are known in the art. For example, a heat-resistant ink such as Norilit™ U from Procell, Inc. can be pad-printed onto a three-dimensional substrate such as the radio wave transparent substrate (121) and can withstand temperatures of up to 220° C. for more than two minutes. Other suitable inks and printing methods are known in the art and can be used with the inventions disclosed herein.

[0144]

[0169] 3- Applying a second surface coating (optional)

[0170] In some embodiments, the method further includes providing a hard coat (128) on at least a portion of the second surface (123) of the radio wave transparent substrate (121). In such embodiments, applying a hard coat to at least a portion of the second surface (123) of the radio wave transparent substrate (121) can provide advantageous functions, including, but not limited to, increasing or affecting the bond between the radio wave transparent substrate (121) and the decorative layer and / or coating (124) and / or intermediate layer (129), controlling residual stress and / or thermal expansion of the decorative layer and / or coating (124), adjusting the color, reflectivity, or other visual appearance of the decorative layer and / or coating (124) and / or intermediate layer (129), and / or providing an interface between a portion of the radio wave transparent substrate (121) and the overmolded second layer (126), thereby affecting adhesion between the two (without an adhesive layer).

[0145]

[0171] Suitable hardcoat layers (128) are described below in Section 7, "Application of Surface Coatings."

[0172] 4-Providing shadow masking

[0173] Methods for applying the decorative layer and / or coating (124), such as physical vapor deposition (PVD), typically require masking to ensure that the deposition of material forming the decorative layer and / or coating (124) is selectively applied to the radio wave transparent substrate (121). As such, the method of the present invention may include providing a shadow mask (104). The shadow mask facilitates selective application of the decorative layer and / or coating (124) to the radio wave transparent substrate (121). The type of shadow mask used will depend on the technique used to apply the decorative layer (124). In some embodiments, the shadow mask is compatible with PVD, particularly sputtering and evaporation. In some embodiments, the shadow mask is stainless steel.

[0146]

[0174] The shadow mask is attached to each surface prior to the application of the decorative layer and / or coating (124). It may be mounted on a radio-transparent substrate (121) or may be positioned within a deposition machine, such as on the target side of a PVD machine.

[0147]

[0175] 5- Application of decorative layers and / or coatings

[0176] The decorative layer and / or coating (124) is applied to only a portion of the second surface (123) of the substrate (121) to provide a visual feature to the radio wave transparent substrate (121). In some embodiments, the radio wave transparent substrate (121) has a mitigated portion (125), and the decorative layer and / or coating (124) is applied to the mitigated portion (125).

[0148]

[0177] By applying the decorative layer and / or coating (124) to only a portion of the substrate (121), this allows for a direct adhesive bond between the first (radio wave transparent substrate) layer (121) and the (second) overmolding layer (126) in the portions where the decorative layer and / or coating (124) is not provided. Without this direct contact bond between the substrate (121) and the overmolding layer (126), the layers could separate.

[0149]

[0178] The decorative layer and / or coating (124) is preferably a reflective layer and comprises any suitable metal, nonmetal, or metal / nonmetal alloy that provides a desired reflective or decorative appearance while also being radio wave transparent. In some embodiments, the metal forming the decorative layer and / or coating (124) comprises a transition metal. In some embodiments, the metal forming the decorative layer and / or coating (124) is indium or tin.

[0150]

[0179] In some embodiments, the reflective layer is abutted by an additional layer. In one embodiment, the reflective layer is between two layers of deposited silicon. These multi-layer stacks allow for tuning of the layers, including their color and residual stress. In some embodiments, multiple layers are deposited on the substrate (121) to form a decorative layer and / or coating (124) prior to overmolding, including a layer of aluminum / silicon and then a layer of silicon followed by another layer of silicon.

[0151]

[0180] The importance of residual stress, the use of interfacial layers in controlling residual stress, and the determination of residual stress parameters are discussed in WO 2011 / 075796 and U.S. Pat. No. 9,176,256, each entitled "PLASTIC AUTOMOTIVE MIRRORS." B2, each of which is incorporated herein by reference in its entirety for all purposes.

[0152]

[0181] In some preferred embodiments, the decorative layer and / or coating (124) comprises a non-metal. The non-metal includes silicon, boron, germanium, arsenic, antimony, and / or tellurium. In particularly preferred embodiments, the non-metal is silicon or germanium. In a most preferred embodiment, the non-metal is germanium. Suitable non-metal / metal alloys include germanium and aluminum and optionally silicon, or germanium and silicon, or germanium and silver and optionally silicon, or germanium and indium and optionally silicon, or aluminum and silicon. In some embodiments, alloys of germanium are germanium and aluminum, or germanium and silicon, or germanium and aluminum and silicon. In some embodiments, the alloy is silicon and aluminum.

[0153]

[0182] When the non-metal / metal alloy contains germanium, the alloy may be at least 25% germanium by weight, or at least 40% germanium by weight, or at least 45% germanium by weight. It is ruthenium, or at least 50% germanium by weight, or at least 55% germanium by weight.

[0154]

[0183] The decorative layer and / or coating (124) is provided as a thin coating layer. In some embodiments, the average thickness of the decorative layer (124) is 20 to 190 nm, or 40 to 170 nm, or 60 to 150 nm. Such thin coatings can be provided by several methods known in the art. However, preferably, the decorative layer (124) is deposited by physical vapor deposition (PVD). Suitable PVD methods include magnetron sputtering and evaporation, which may be resistive thermal evaporation or electron beam evaporation. In some embodiments, the decorative layer (124) is deposited by magnetron sputtering.

[0155]

[0184] Ideally, the shaping of the radio wave transparent substrate (121) (in embodiments in which the radio wave transparent substrate is molded), the application of any intermediate layer (129), and the application of the decorative layer and / or coating (124) are performed on the same machine. Alternatively, each step may be performed by separate machines arranged to operate sequentially.

[0156]

[0185] 6- Heating of the substrate and decorative layers and / or coatings

[0186] It may be advantageous to heat the substrate (121) and the decorative layer and / or coating (124) before applying the second shot overmolding layer (126). Such heating (106) allows for some thermal expansion at a slower rate than that encountered during the overmolding process (107), thus limiting the rate of change in temperature of the decorative layer (124) and substrate (121) during overmolding. This reduces visual defects, such as crazing, during the overmolding step (107). Thus, in some embodiments of the method of the present invention, the substrate (121) and the decorative layer and / or coating (124) are heated prior to overmolding. In some embodiments, the substrate (121) and the decorative layer (124) are heated to at least 70°C, or at least 80°C, prior to the overmolding step (107).

[0157]

[0187] 7-Overmolding layer

[0188] Once in place, the overmold layer (126) provides a third (rear) surface (127) that is parallel or substantially parallel to the first surface (122) of the radio wave transparent substrate (121) over at least a portion of the radome. The parallel or substantially parallel portions define a radio wave path through which radio waves can pass. Importantly, the parallel or substantially parallel nature of the first and third surfaces minimizes differences in the refraction of radio waves as they pass through different portions of the radome's radio wave path.

[0158]

[0189] Different thermoplastics / thermal polymers have different flow temperatures and therefore require different barrel nozzles for injection molding. Typically, higher temperatures result in an increased likelihood of damage and visible defects in the decorative layer and / or coating (124) when overmolded. Therefore, it is preferable to use a thermoplastic / thermal polymer that has a relatively low nozzle temperature or a nozzle temperature below the crazing point of the decorative layer and / or coating (124).

[0159]

[0190] Melting and molding temperatures for various common thermoplastics are provided in Table 1 below.

[0160] [Table 1]

[0161]

[0191] Further specifications for thermoplastic materials are provided by the International Organization for Standardization and are specified in particular in Standard Catalogue 83.080.20.

[0192] In some embodiments, the overmolded layer (126) is formed at a barrel nozzle temperature of 300° C. or less. In some embodiments, the barrel nozzle is 280° C. or less during the overmolding process (107). In some embodiments, the barrel nozzle is 250° C. or less during the overmolding process (107). In some embodiments, the barrel nozzle is 230° C. or less during the overmolding process (107). Suitable polymers that can be injection molded at these barrel nozzle temperatures are known in the art and are determined by their melting temperatures.

[0162]

[0193] 8- Applying surface coating

[0194] Additionally, some embodiments of the method of the present invention include providing a hard coat (128) on the first surface (122) of the radio wave transparent substrate (121). The essential function of a radome is to provide protection for radar equipment from the environment. As such, the radome is susceptible to degradation, wear, and damage. This exposure is further amplified when the radome is positioned at the front of a vehicle where it is routinely exposed to relatively high speeds, abrasives, flying objects, and chemicals used in cleaning. In this regard, the coating (128), which is said to be a "hard coating," is a coating that is harder than the radio wave transparent substrate (121), thereby increasing the wear resistance of the radio wave transparent substrate (121).

[0163]

[0195] Such abrasion-resistant hard coatings (128) reduce damage caused by impacts and scratches. Abrasion resistance can be measured through standard tests such as ASTM F735 "Standard Test Method for Abrasion Resistance of Transparent Plastics and Coatings Using the Vibrating Sand Method," ASTM D4060 "Standard Test Method for Abrasion Resistance of Organic Coatings" using a Taber Abrasion Tester, or by using the known steel wool test.

[0164]

[0196] Furthermore, some plastics can be damaged by certain solvents; for example, polycarbonate is damaged by acetone. A requirement of many automotive exterior parts, such as radomes, is that they be "chemically resistant," which refers to their ability to withstand exposure to common solvents such as diesel, petroleum, battery acid, brake fluid, antifreeze, acetone, alcohol, automatic transmission fluid, hydraulic fluid, and ammonia-based window cleaners. In this regard, a hard coating ideally provides such chemical resistance to at least the first surface of the radome.

[0165]

[0197] The hard coating (128) on the first surface (122) and / or second surface (123) of the radio wave transparent substrate is preferably formed from one or more abrasion-resistant layers and may include a primer layer that firmly bonds to the substrate (121) to form a favorable surface for a subsequent abrasion-resistant layer. The primer layer may be provided by any suitable material, for example, an organic resin such as an acrylic polymer, a copolymer of an acrylic monomer and methacryloxysilane, or a copolymer of a methacrylic monomer and an acrylic monomer having a benzotriazole group or a benzophenone group. These organic resins may be used alone or in combination of two or more.

[0166]

[0198] The hard coat layer (128) is preferably made of organosilicon, acrylic, urethane, melamine, or amorphous SiO x C y H z It is formed from one or more materials selected from the following group.

[0167]

[0199] Commercially available hard coatings include Momentive PHC-587B, Momentive UVHC 5000 (UV cured), and PR6600 (SDC The coating comprises a two-part product that includes a primer coat from SDC Technologies and is subsequently coated with MP101 (SDC Technologies).

[0168]

[0200] Most preferably, the hard coat layer (128) is an organosilicon layer due to its excellent abrasion resistance and compatibility with physical vapor deposition films. For example, hard coating layers comprising organosilicon polymers may be prepared using the following compounds: methyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxyethoxysilane, methyltriacetoxysilane, methyltrippropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, phenyltrimethyl ... Triethoxysilane, Phenyltriethoxysilane, Phenyltriacetoxysilane, Gamma-Chloropropyltrimethoxysilane, Gamma-Chloropropyltriethoxysilane, Gamma-Chloropropyltripropoxysilane, 3,3,3-Trifluoropropyltrimethoxysilane, Gamma-Glycidoxypropyltrimethoxysilane, Gamma-Glycidoxypropyltriethoxysilane, Gamma-(beta-glycidoxyethoxy)propyltrimethoxysilane, Beta-(26,4-epoxycyclohexyl)ethyltrimethoxysilane Trialkoxysilanes or trialkoxysilanes such as methoxysilane, beta-(26,4-epoxycyclohexyl)ethyltriethoxysilane, gamma-methacryloxypropyltrimethosylsilane, gamma-aminopropyltrimethoxysilane, gamma-aminopropyltriethoxysilane, gamma-mercaptopropyltrimethoxysilane, gamma-mercaptopropyltriethoxysilane, N-beta(aminoethyl)-gamma-aminopropyltrimethoxysilane, beta-cyanoethyltriethoxysilane, and the like. Reasiloxysilane, as well as dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldiethoxysilane, phenylmethyldiethoxysilane, gamma-glycidoxypropylmethyldimethoxysilane, gamma-glycidoxypropylmethyldiethoxysilane, gamma-glycidoxypropylphenyldimethoxysilane, gamma-glycidoxypropylphenyldiethoxysilane, gamma-chloropropylmethyldimethoxysilane, gamma-chloropropylmethyldiethoxysilane, dimethyldiacetoxy The silane may be formed of a compound selected from dialkoxysilanes or diacyloxysilanes such as gamma-methacryloxypropylmethyldimethoxysilane, gamma-methacryloxypropylmethyldiethoxysilane, gamma-mercaptopropylmethyldimethoxysilane, gamma-mercaptopropylmethyldiethoxysilane, gamma-aminopropylmethyldimethoxysilane, gamma-aminopropylmethyldiethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, and the like.

[0169]

[0201] The hard coat layer (128) can be applied to a substrate (such as the radio wave transparent substrate (121)) by dip coating in a liquid followed by solvent evaporation, or by plasma-enhanced chemical vapor deposition (PECVD), flow coating, or spray coating with a suitable monomer. To improve the abrasion resistance of the hard coating (128), subsequent coats of hard coating can be added, preferably within 48 hours, to avoid aging and contamination of the previous coat. These additional coats can be applied to either the first surface (122) or the second surface (123) of the substrate (121).

[0170]

[0202] The thickness of the hard coat layer (128) is preferably selected to help provide adequate abrasion resistance. The appropriate abrasion resistance will be determined by the required application and user needs. In some applications, adequate abrasion resistance may be considered a Bayer abrasion rating of 5 against an uncoated plastic substrate (121, such as polycarbonate), or alternatively, a Taber abrasion test with a delta haze of less than 15% (% haze measured per ASTM D1003) after 500 cycles with a 500 g load and a CS10F wheel. If these requirements are met, when an organosilicon is used as the hard coating (128), the hard coat thickness preferably averages a minimum of at least 6 μm thick and / or has a maximum thickness of 28 μm thick.

[0171]

[0203] Further coatings to those discussed above may be applied to the first surface of the radio wave transparent substrate to modify the surface properties of the substrate, in addition to those discussed above. For example, a cap layer may also be provided by a material having properties including hydrophobicity, hydrophilicity, oleophobicity, lipophilicity, and oleophobicity, or a combination thereof.

[0172]

[0204] Decorative radome

[0205] The present invention therefore provides, in a second alternative, a decorative radome comprising a first layer (121) comprising a radio wave transparent polymer, the first layer (121) having a front surface (122), a second layer (126) comprising a radio wave transparent polymer, the second layer (126) having a rear surface (127), and a decorative layer and / or coating (124) between the first layer (121) and the second layer (126) comprising a metal or an alloy comprising a metal and a non-metal, wherein the second layer (126) directly abuts the decorative layer (124), the first layer (121) is directly adhesively bonded to the second layer (126), and at least one of the first layer (121) or the second layer (126) consists of a polymer (thermal polymer) that can be overmolded at barrel nozzle temperatures below 300 degrees Celsius.

[0173]

[0206] Additionally, the decorative radome of the present invention may include a hard coat (128) provided on the first surface (122) of the radome.

[0207] It should be understood that the term "directly adhesively bonded" refers to a physicochemical phenomenon resulting from the molecular attractive forces acting between the second layer (126) and the first layer (121) in contact, and is expressly considered to exclude bonds formed solely by adhesive.

[0174]

[0208] Further measures can be taken to improve the connection between the respective elements of the radome. According to the invention, in particular, respective surface structures can be provided to lead to a form-fit connection, in particular in addition to glue, adhesive and / or chemical bonding. Such surface structures are described with the help of Figure 15 in relation to the second alternative of the invention, but those skilled in the art will understand that such surface structures can also be used and implemented in the first alternative of the invention to lead to a form-fit connection.

[0175]

[0209] Elements of the radome shown in FIG. 15 that correspond to elements of the radome shown in FIG. 13 have the same reference numbers but are increased by 100.

[0210] As shown in Figure 15, the radome, or more precisely the substrate (221), comprises a first surface structure formed by elements (230, 232) in the area of the decorative coating (224). The elements (230) are formed as mushroom-like protrusions. When the decorative coating (224) is applied to the substrate (221), the coating (224) surrounds the protrusions (230) so as to form a form-fit connection. The elements (232) are formed as undercuts. When the decorative coating (224) is applied to the substrate (221), portions of the decorative coating (224) reach into the undercuts (232) so that the decorative coating (224) is also form-fit connected to the substrate (221).

[0176]

[0211] To achieve an enhanced connection between the substrate (221) and the overmolded layer (226), the substrate (221) further comprises a second surface structure comprising elements (234, 236). The elements (234) are formed as groove-shaped undercuts. When the overmolded layer (226) is formed in the second molding step, the overmolded material also flows into the undercuts (234), thus providing a form-fit connection between the substrate (221) and the overmolded layer (226). In addition, mushroom-shaped protrusions (236) are formed on the substrate (221) to improve the connection between the substrate (221) and the overmolded layer (226). When the layer (226) is molded, the overmolded material surrounds the protrusions (236), providing a form-fit connection between the substrate (221) and the overmolded layer (226).

[0177]

[0212] In embodiments not shown, the surface structure may be provided by at least one separately formed anchor element. In other words, the surface structure does not necessarily have to be integrally formed with the substrate and / or decorative coating. Also, the surface structure, especially the adhesive, may be provided by at least one separately formed anchor element. The anchor element can be formed from a material different from that of the substrate and / or decorative coating. The anchor element can be located, for example, in a mold, before the substrate and / or decorative coating are formed. In this manner, the anchor element is at least partially embedded and / or overmolded.

[0178]

[0213] The decorative radome of the present invention does not substantially attenuate electromagnetic frequencies between 10 MHz and 3000 GHz. Specifically, in some embodiments, the radome has a radar attenuation of less than 2 dB in one direction across the signal path (4 dB in both directions), and preferably less than 1 dB in one direction across the signal path (2 dB in both directions). Furthermore, the decorative layer (124) comprising a metal or metal and non-metal alloy has a radar attenuation of less than 10 dB in one direction across the signal path (2 dB in both directions). 6 It has a sheet resistance greater than ohms per square (Ω / □).

[0179]

[0214] Advantageously, the direct adhesive bond formed between the first layer (121) and the second layer (126) improves the weather resistance of the radome compared to radomes formed with adhesively bonded layers. Thus, in some embodiments, there is no water intrusion between the first layer (121) and the second layer (24) when immersed in water at 60° C. for 240 hours.

[0180]

[0215] The decorative radome according to the second alternative may be produced according to the method disclosed above. Alternatively, the decorative radome may be produced by any suitable method that provides all of the required claimed features and functionality. Importantly, the decorative radome of the present invention should be considered to optionally include the structural and functional features disclosed above in connection with the method.

[0181]

[0216] The decorative radome of the present invention, or the decorative radome produced by the method of the present invention, can be used in any suitable context. In an embodiment, the radome is an automobile badge. In some forms, the automobile badge can include additional features, functions, and aesthetic elements. In some embodiments, the radome can be used in combination with a lighting assembly, or each can be referred to as "A LIGHT ASSEMBLY AND A VEHICLE DESIGN ELEMENT INCLUDING SUCH A LIGHT."

[0023] The present invention may include additional features as described in WO2017 / 009260 and U.S. Patent Publication No. 2018 / 0202626 A1, entitled "COMPARATIVE PARTICLE BASED ON AN ELECTRONIC SUBSTRATE ASSEMBLY," each of which is incorporated herein by reference in its entirety for all purposes.

[0182]

[0217] The term "reflectivity" refers to the reflection of visible light, typically at nanometer wavelengths and in the frequency range of 400-800 THz. The reflectivity percentage can be measured using techniques known in the art or as discussed below.

[0183]

[0218] References to radio waves throughout this specification typically refer to frequencies between 10 MHz and 3000 GHz. In preferred embodiments, and in connection with automobiles, the frequencies are typically between 1000 MHz and 100 GHz. In some specific embodiments related to radomes for vehicles, the frequencies are between 24 GHz and 79 GHz, or between 77 GHz and 79 GHz, or 24 GHz, 77 GHz, or 79 GHz.

[0184]

[0219] The terms "transparent" and "opaque," when used without a modifier (such as "radio" or "radar"), refer to visually transparent or opaque, and thus are references to transmission or absorption of visible light as defined above.

[0185] Radome technical characteristics

[0220] To minimize refraction of the radar signal as it passes through the radome, the front and rear surfaces must be parallel or substantially parallel. The sides should be free of significant variations in material density such as gaps, bubbles, or water intrusion, and the decorative layer should be of uniform thickness.

[0186]

[0221] The surface resistivity of the decorative layer can be determined using a four-point method using a four-point probe according to JIS K7194. 6 It must exhibit low electrical conductivity, greater than Ω / □ (ohms per square) (ie, the reflective layer is electrically insulating in situ).

[0187]

[0222] The radio wave attenuation and reflection rate will be determined by the user's requirements, the application, the frequency used, and the equipment being used, but preferably there will be a minimum of 10 dB reflection and a maximum of 1 dB one-way (2 dB two-way) transmission loss at the sensor operating frequency, typically 24 GHz, 77 GHz, or 79 GHz.

[0188]

[0223] Radome attenuation and technical characteristics

[0224] The decorative radome of the present invention does not substantially attenuate electromagnetic frequencies between 10 MHz and 3000 GHz. Specifically, in some embodiments, the radome has radar attenuation of less than 2 dB in one direction across the signal path (4 dB in both directions), and preferably less than 1 dB in one direction across the signal path (2 dB in both directions). Furthermore, the decorative layer (6) comprising a metal or metal and non-metal alloy has a radar attenuation of less than 10 dB in one direction across the signal path (2 dB in both directions). 6 The surface resistivity of the decorative layer (6) can be determined using a four-point method using a four-point probe according to JIS K7194, which has a sheet resistance greater than ohms per square (Ω / □).

[0189]

[0225] The front and rear surfaces must be parallel or substantially parallel to minimize refraction of the radar signal as it passes through the radome (1) according to alternative 1 and / or the radome according to alternative 2. Furthermore, the inside of the radome (1) must be free of significant variations in material density, such as gaps, air bubbles, or water intrusion, and the decorative layer and / or coating (5, 124) must be of uniform thickness.

[0190]

[0226] The radio wave attenuation and reflectance will be determined by the user's requirements, the application, the frequencies used, and the equipment being used. However, in some embodiments, at a specific operating frequency of 76-81 GHz, there will be a maximum of 2 dB attenuation in one direction (4 dB in both directions). In some embodiments, at 24 GHz, 77 GHz, or 79 GHz, there will be less than 2 dB attenuation in one direction. In some embodiments, at a specific operating frequency of 76-81 GHz, there will be a maximum of 1 dB attenuation in one direction (4 dB in both directions). In some embodiments, at 24 GHz, 77 GHz, or 79 GHz, there will be less than 1 dB attenuation in one direction. radar system

[0227] In some embodiments, the present invention provides a radar system as illustrated in FIG. 7, including a radio wave transmitter (10), a radio wave receiver (10), and a decorative radome (1) as described herein.

[0191]

[0228] The radome (1) may be in the radio wave path of both the radio wave receiver and transmitter (which may be integrated into one device), or there may be a radome associated with the transmitter and another radome associated with the receiver.

[0192]

[0229] The substrate attenuates the radio signal as it passes through the radome (1). Part of this attenuation is a product of reflection of the radio signal from the first surface (3) or second surface (4) of the substrate (2, 121) as the radio wave emanating from the transmitter passes through the radome. Consequently, the attenuation resulting from reflection is determined by the thickness of the substrate (2, 121) (and coating) and any potential overmolding layers in relation to the wavelength of the radio signal. The wavelength varies depending on the dielectric constant of the substrate and / or overmolded layer. Therefore, the substrate thickness that provides the minimum attenuation is given by the formula

[0193]

number

[0194] where m is an integer and λ is the wavelength through the substrate and / or overmolding layer of the radio wave transmitted from the radio wave transmitter for which the radome is designed. Consequently, in some embodiments, the thickness of the radome substrate and / or overmolding layer is determined by

[0195]

number

[0196] is a multiple of.

[0197]

[0230] Radar systems in vehicles typically use microwaves to provide line-of-sight detection of objects. The three frequencies currently used for automobiles are 24 GHz, 77 GHz, and 79 GHz. In recent years, 77 GHz and 79 GHz have become the dominant frequencies used because they offer improved range and resolution compared to the 24 GHz frequency. Specifically, 77 GHz can identify objects with three times higher resolution than 24 GHz while using an antenna size that is three times smaller in height and width (having only one-ninth the area).

[0198]

[0231] Radar systems using 24 GHz can utilize both narrowband (NB) spanning 200 MHz from 24.05 GHz to 24.25 GHz, and ultra-wideband (UWB) spanning 5 GHz from 21.65 GHz to 26.65 GHz.

[0199]

[0232] Due to spectrum regulations and standards developed by the European Telecommunications Standards Institute (ETSI) and the US Federal Communications Commission (FCC), use of UWB bands will be phased out in both Europe and the US by 2022 (the "Cessation Date").

[0200]

[0233] 24GHz NB and UWB are being replaced by frequencies between 71 and 81GHz, with the 76-77GHz range representing long-range radar (LRR) and the 77-81GHz range representing short-range radar (SRR). The 77-81GHz range offers a sweep bandwidth of up to 4GHz, which is much larger than the 200MHz available in 24GHz NB.

[0201]

[0234] In some embodiments, the radome is designed for or used in a radar system in which the radio transmitter (10) transmits radio waves in a frequency range of 20 GHz to 81 GHz. In some embodiments, the radome is designed for or used in a radar system in which the radio transmitter transmits radio waves in a frequency range of 76 to 81 GHz, or 76 to 77 GHz, or about 77 GHz, or about 79 GHz.

[0202]

[0235] To minimize attenuation, in some embodiments of the decorative radome, the substrate is between 2 mm and 2.6 mm thick. In some embodiments, the substrate is about 1.15 mm thick. , 2.3mm, or 2.45mm thick.

[0203] Heated radome

[0236] Radio waves are typically attenuated by water, and in particular by ice. It is therefore desirable to prevent ice formation on the surface of the radome. Consequently, as illustrated in Figure 6, a decorative radome (1) according to a first alternative of the present invention includes a layer including a heating element (11). Such a heating layer may also be provided in a radome according to a second alternative of the present invention. The heating layer may be an additional layer, in particular an additional and / or alternative intermediate layer, which may be at least partially formed by an overmolded layer or at least partially formed by the substrate.

[0204]

[0237] Suitable heating elements suitable for use with radomes are disclosed in DE102014002438A1, DE10156699A1, US20180269569A1, which are incorporated herein by reference in their entirety for all purposes.

[0205]

[0238] In a preferred embodiment, the heating element (11) comprises a radar-transparent polymer with an embedded resistive wire circuit (12) that may be embedded or molded into the heating element substrate (11) to form a network that substantially covers the radome.

[0206]

[0239] The heating element (11) may be provided by a polymer film including a circuit (12) that may be provided between the radio wave transparent substrate (2) and the decorative coating (5). The heating element may also be formed at least in part by an overmolding layer. As such, the polymer film (11) must also be radio wave transparent. Consequently, the polymer film (11) may be made of any suitable polymer disclosed for the radio wave transparent substrate (2). Thus, the polymeric membrane (11) can be made of a polymer selected from the group including, but not limited to, acrylonitrile-ethylene-styrene (AES), acrylonitrile-butadiene-styrene (ABS), acrylonitrile-styrene-acrylate (ASA), polyamide (PA), polybutylene terephthalate (PBT), polycarbonate (PC), polyethylene (PE), polyethylene terephthalate (PET), poly(methyl methacrylate) (PMMA), polyoxymethylene (POM), polypropylene (PP), polyurethane (PU), polyvinyl chloride (PVC), high-flow AES, acrylonitrile-(ethylene-propylene-diene)-styrene (AEPDS), a blend of thermoplastics, or a PC-ABS blend thermoplastic. In some embodiments, the polymeric membrane (11) containing the circuitry (12) will be formed of polycarbonate or polypropylene.

[0207]

[0240] Alternatively, the circuitry may be embedded or molded into the radio wave transparent substrate (2) of the radome (1) such that the circuitry (12) is provided within the radio wave transparent substrate (2) without the need for additional layers.

[0208]

[0241] Illuminated radome

[0242] Automotive emblems are traditionally used to communicate vehicle styling and branding. The radome according to the present invention allows for the incorporation of such automotive emblems, e.g., logos, as visual features. There is a further desire to enhance such visual features, particularly emblems, with illumination to improve brand identification. This illumination may be of the logo itself, a ring around the emblem, or the entire automotive badge.

[0209]

[0243] However, it is difficult to integrate lighting and radar functionality into a badge / emblem. As already discussed before, the radome is preferably made of a material that is dielectrically stable according to the dielectric properties of the material. It is also desirable to have minimal interfaces between dissimilar materials so as not to adversely affect radio wave transparency.

[0210]

[0244] Conversely, badge illumination typically uses additional components to transmit, diffuse, reflect, and pipe the necessary light, resulting in reduced radio wave penetration due to the effects previously described without further measures such as increasing the overall thickness of the radome. Thus, illumination implementations often defeat the purpose of optimal radio wave / radar performance.

[0211]

[0245] However, the radome of the present invention makes it possible to provide illumination that avoids the problems previously described. This objective is achieved by at least partially using existing structures and elements as the illumination system. In particular, each layer or coating is used as an optical waveguide into which light from a light source is coupled. The light is guided by the layer or coating and falls onto visual features from which it is reflected and / or scattered.

[0212]

[0246] In Figure 16 an exploded cross-sectional view of a radome including an illumination system is shown. Elements of the radome corresponding to the radome as shown in Figure 13 have the same reference numbers but increased by 200. The radome of Figure 16 comprises a molded substrate (321), preferably comprising polycarbonate that is transparent to visible light. The substrate (321) is provided in particular in a first-shot molding step.

[0213]

[0247] A visual feature, particularly in the form of a logo, is provided on the substrate 321, particularly in the area of the relief portion 325. The logo is formed by a decorative coating 324. The coating 324 is particularly radar / radio-transparent and reflective to visible light and may comprise AlGe applied by a PVD coating process.

[0214]

[0248] The substrate (321) and decorative coating (324) are overmolded with an overmolding layer (326), which is opaque to visible light but radio / radar transparent, and which is provided in a second-shot molding step and / or comprises an AES material, particularly a dark AES, such that the decorative coating is encapsulated between the visible-light-transparent substrate (321) and the visible-light-opaque overmolding layer (326).

[0215]

[0249] The substrate (321) is further protected by a second surface coating in the form of a hard coat (328), in particular a thermal hard coat, as already described in the previous embodiment.

[0216]

[0250] 16 further shows a radio wave transceiver comprising, inter alia, a radar unit 340. On the opposite side of the radome, an observer looking at the radome is visualized for purposes of illustration by an eye 342.

[0217]

[0251] The illumination system of the radome comprises two light sources (344), in particular comprising LEDs. By the light sources (344), a light beam (346) is coupled into the substrate (321). The substrate (321) also partially forms part of the illumination system, acting as a light guide such that light is coupled from the light sources (344) into the light guide. The light is guided through the substrate (321), as indicated by arrows (348).

[0218]

[0252] In the lightened portion (325), the light is at least partially reflected / scattered by the decorative coating (324) towards the viewer (324), as indicated by the arrow (350). In this way, the viewer can clearly see the visual features formed by the decorative coating (324), particularly the logo, due to the illumination. In particular, the arrow (3 Viewing the radome along arrow (352) makes it appear reflective to light, while viewing the radome along arrow (354) makes it appear glossy black due to the absence of decorative coating in this area as well as the opaque, particularly dark, overmold layer (326).

[0219]

[0253] The light source 344 specifically represents an edge lighting source because light is coupled into a light guide in the form of the substrate 321 in a direction that is primarily perpendicular to the normal N of the surface of the substrate 321. The relief portion 325 in the substrate 321 can be designed at an angle to optimize the pickup of light guided through the substrate 321. The use of an edge lighting source has the advantage that the light source 344 is located outside the radar signal transmission / reception area and therefore does not affect radar detection requirements.

[0220]

[0254] Additionally, the light source may be hidden behind a support structure of the radome, such as a bezel, grille, or the like.

[0255] With the previously described illumination system and production method, optimal radio wave / radar transparency is reached as a transition in the dissimilar materials, and voids are avoided due to the absence of additional elements located in the radar transmission area for illumination purposes. Furthermore, since there are no additional elements located in the transmission area for illumination, it is possible to provide a section with a uniform thickness for radio wave / radar transmission.

[0221]

[0256] A further example of a radome of the invention equipped with an illumination system is shown in Figure 17. Elements of the radome shown in Figure 17 that correspond to elements of the radome shown in Figure 16 have the same reference numbers but increased by 100.

[0222]

[0257] As shown in Figure 17, the use of the illumination system is not limited to planar or flat radomes. The radome may also have a curved cross section without adversely affecting the illumination function.

[0258] Light from a light source 444, shown as light ray 446, is coupled into the substrate 421. The substrate 421 acts as a light guide because the light ray within the substrate undergoes internal reflection, as indicated by arrow 448. Therefore, the light is not significantly scattered out of the substrate 421 and is guided along the substrate 421 until it falls onto the decorative coating 424 in the mitigated area 425. From there, the light is reflected and / or scattered out of the substrate 421 along arrow 450 and is seen by an observer.

[0223]

[0259] In Figure 18, a diagram for an actual radome including an illumination system as previously described is shown. Elements of the radome shown in Figure 18 that correspond to elements of the radome shown in Figure 17 have the same reference numbers, but increased by 100. In Figure 18, a view onto the second surface of the radome's substrate (521) is shown. Light from the light source (544) is coupled into the substrate (521) and reflected / scattered by the decorative coating (524), resulting in a visual feature in the form of a logo (552) being visible. In areas outside the logo (552) and the decorative coating (524), illumination is reduced because only the opaque overmold layer (526) is visible.

[0224]

[0260] Although the illumination system has been described in combination with the second alternative of the present invention, those skilled in the art will recognize that the illumination system is also applicable to the first alternative. In the first alternative, a layer adjacent to the decorative coating, or a layer of the decorative coating adjacent to the reflective layer of the coating, is used as a light guide. For example, a stress control layer (8) or a hard coat layer (9) may allow the light to be guided from where it is reflected and / or scattered to the reflective area of the decorative coating. [Example]

[0225] Substrate Attenuation Board Thickness

[0261] To assess the substrate's effect on radio wave attenuation in the 76-77 GHz band, bare (uncoated) polycarbonate samples at approximately 2, 2.3, 3, 4.5, and 6 mm (actual thicknesses of 2.0, 2.33, 2.92, 4.42, and 5.84 mm) were obtained and evaluated in a Rohde-Schwartz (R&S®) QAR system at a 10-degree tilt angle according to the manufacturer's instructions. The data was analyzed, and a line of best fit was then applied to the results. The assumed dielectric constant of polycarbonate at 77 GHz is 2.8.

[0226]

[0262] Different dielectric substrates have different dielectric constants, which results in a variation in the wavelength of the radio waves across the substrate. Polycarbonate has a relative dielectric constant (εr) of 2.8 at 77 GHz, so the calculated wavelength through the substrate is 2.328 mm.

[0227]

[0263] As can be seen in Figure 8, the attenuation followed a sloped sinusoid, with periodic minima at substrate thicknesses that were integer multiples of half wavelengths (i.e., 0.5, 1, 1.5, 2, 2.5, etc., of the wavelength of the radio waves passing through the substrate), and maximum attenuation at quarter wavelengths offset from the minimum (i.e., 0.75, 1.25, 1.75, etc., of the wavelength of the radio waves passing through the substrate). Furthermore, the average attenuation across the sinusoid increased as the sheet thickness increased.

[0228]

[0264] In view of other design requirements for radome use in vehicles, the optimum thickness was selected at 2.3 mm, which provided minimum damping, as well as adequate robustness, stiffness, and weight for use as an automotive body component.

[0229] Attenuation of 77GHz vs. 79GHz radio waves

[0265] To measure attenuation at common radio frequencies used in automotive radar systems, 2 mm (FIG. 9A) and 2.3 mm (FIG. 9B) polycarbonate substrates were assessed over frequencies from 76-81 GHz using an R&S® QAR system according to the manufacturer's instructions.

[0230]

[0266] As can be seen in Figure 9A, the average attenuation over the 76-77 GHz frequency was approximately 117% of the average attenuation over the 76-81 GHz frequency when the polycarbonate substrate was 2 mm. By comparison, and as shown in Figure 9B, the average attenuation over the 76-77 GHz frequency was approximately 83% of the average attenuation over the 76-81 GHz frequency when the polycarbonate substrate was 2.3 mm. As such, the percentage variation between the 2 mm and 2.3 mm substrates was 17%, albeit in opposite directions, when the average attenuation over the 76-77 GHz frequency is compared to the average attenuation over the 76-81 GHz frequency.

[0231]

[0267] However, the difference in actual attenuation was only 0.06 dB when the substrate was 2.3 mm, compared to 0.14 dB when the substrate was 2 mm. Therefore, 2.3 mm appears to be the most suitable choice for use with radar systems that use both the 77 GHz and 79 GHz bands.

[0232] Shiny metallic look

[0268] A radio wave transparent decorative polymer sheet was prepared with a glossy metallic appearance according to the following protocol.

[0233] Substrate preparation

[0269] Polycarbonate substrates were prepared by applying a base hardcoat layer of Momentive PHC587B using an automated dip-coating process consisting of detergent washing, coarse rinsing, fine rinsing, further fine rinsing, drying, cooling, and then dip coating and flash-off. The dip-coating process was robotically controlled with precise removal rates to control the hardcoat thickness. The first-surface hard-coated substrate was allowed to stand for 10 minutes to allow the solvent to evaporate until the surface was substantially tack-free. The first-surface coated substrate was then cured in a curing oven for 71 minutes at 130°C to provide the hard-coated substrate.

[0234] decorative coating

[0270] A decorative coating comprising a layer of aluminum and germanium alloy and an overlayer of silicon dioxide (SiO2) was deposited according to the following parameters:

[0235] [Table 2]

[0236] Protective Surface Coating - Crystal Clear Hard Coat

[0271] To provide a glossy finish and protect the decorative coating, a protective surface hard coat layer of Momentive PHC587B was applied as a top (protective hard coat) layer to the decorative coating. This was completed by an automated spray coating process in a dedicated thin film coating spray booth. The first surface coated substrate was allowed to stand for 10 minutes to allow the solvent to evaporate until the surface was substantially tack-free. The first surface coated substrate was then cured in a curing oven for 71 minutes at 130°C to provide a protective hard coated surface.

[0237] Bright satin metallic look

[0272] The radio wave transparent decorative polymer sheet was coated with a satin metallic finish according to the following protocol. Prepared with appearance.

[0238] Substrate Preparation and Decorative Coatings

[0273] A polycarbonate substrate was provided with a first surface hard coating and a decorative coating comprising a layer of an alloy of aluminum and germanium as presented above for the "glossy metallic look" and a silicon dioxide layer.

[0239] Protective Surface Coating - Satin Hard Coat To provide a satin metallic look, a protective hard coat containing an additive that results in the diffusion of visible light was applied. Specifically, the following parameters were used:

[0240] [Table 3]

[0241] Mechanical Testing

[0274] To assess whether the decorative coated radomes are sufficiently robust for use in automotive applications, a series of durability tests were performed on gloss metallic and satin metallic look samples prepared as described above.

[0242]

[0275] The tests performed and the results are summarized in Table 4 below.

[0243] [Table 4]

[0244] Coated substrate attenuation

[0276] Polycarbonate sheets of 2.0, 2.3, 2.92, 4.42, and 5.84 mm were coated with either a gloss metallic coating or a satin metallic coating as described above. To evaluate the effect of substrate thickness on the reflection and attenuation of radar signals in the 76-77 GHz band, the coated polycarbonate sheets were assessed at a 10-degree tilt angle in a Rohde-Schwartz (R&S®) QAR system. The applied decorative coating thicknesses could be up to 0.03 mm thick, providing total thicknesses of 2.03, 2.33, 2.95, 4.45, and 5.87 mm. The results are shown in Table 5 below.

[0245] [Table 5]

[0246]

[0277] As can be seen above, the one-way attenuation and reflection of the coated 2.33mm polycarbonate did not change significantly based on the coating applied. Furthermore, the best thickness was 2.33mm, with an attenuation of 1.1dB and 1.18dB (gloss, satin), and a reflection of 10% and 9% (gloss, satin).

[0247]

[0278] The comparative attenuation of coated and uncoated substrates is illustrated in Figure 10 (data generated with a best-fit sinusoidal curve). As can be seen, adding a coating (gloss or satin) increases the attenuation. However, the attenuation at 2.33 mm is still at a level compliant with that required for automotive radar systems.

[0248] Visual characteristics

[0279] 2 mm and 2.3 mm polycarbonate substrates were coated to provide either a gloss metallic look or a satin metallic look as described above, and the visual properties at the center of the coated substrates were measured with illuminant A / 2.

[0249]

[0280] The CIELAB color chart measured using illuminant A / 2 is shown in Figure 11, and the reflectance measurements ("Rsin" which includes specular reflection and "Rsex" which excludes specular reflection) are provided in Table 6 below.

[0250] [Table 6]

[0251]

[0281] Reflectivity, including specular and diffuse reflectance (Rsin), was comparable for both the gloss metallic and satin metallic appearance samples. However, reflectivity for the 2.3 mm samples was typically higher than for the 2 mm samples. is likely an artifact of the coating process as the 2.3 mm sample consisted of a smaller slab compared to the A4 size 2 mm sample, and as such, the 2.3 mm sample was closer to the splatter target during deposition.

[0252]

[0282] All methods described herein may be performed in any suitable order unless otherwise indicated herein or clearly contradicted by context. The use of any and all examples or exemplary language provided herein (e.g., "etc.") is intended solely to further clarify example embodiments and does not inherently impose limitations on the scope of the claimed invention. However, such embodiments may be subject to claimed limitations or may be considered additional features if included within the scope of the claims. No language in the specification should be construed as indicating any non-claimed element as essential.

[0253]

[0283] The description provided herein relates to several embodiments that may share common characteristics and features. It should be understood that one or more features of one embodiment may be combinable with one or more features of other embodiments. In addition, a single feature or combination of features of an embodiment may constitute an additional embodiment.

[0254]

[0284] The headings used herein are included solely for the reader's ease of reference and should not be used to limit the subject matter found throughout this disclosure or the claims. The headings should not be used to interpret the scope or limitations of the claims.

[0255]

[0285] Those skilled in the art will understand that the invention described herein is susceptible to variations and modifications other than those specifically described. The invention is to be understood to include all such variations and modifications. The invention also includes all of the steps, features, and / or functions, individually or collectively, referred to or shown in this specification, and any and all combinations of any two or more of the steps or features.

[0256]

[0286] Throughout this specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising" will be understood to imply the inclusion of a stated element or integer or group of elements or integers, but not the exclusion of any other element or integer or group of elements or integers.

[0257]

[0287] Also, it should be noted that as used herein, the singular forms "a," "an," and "the" include plural references unless the context already dictates to the contrary.

[0258]

[0288] Future patent applications may be filed in Australia or overseas based on or claiming priority from this application. It should be understood that the following provisional claims are provided by way of example only and are not intended to limit the scope of what may be claimed in any such future application. Also, features may be added to or omitted from the provisional claims at a later date so as to further define or redefine the invention.

Claims

1. a radio wave transparent substrate (321, 421, 521) having a first surface (422) on a first side surface and a second surface (423) on a second side surface; a radio wave transparent decorative coating (324, 424, 524) for providing at least one visual feature on the radio wave transparent substrate (321, 421, 521), the radio wave transparent decorative coating (324, 424, 524) including a decorative layer comprising or consisting of a metal, or comprising or consisting of an alloy containing a metal; a stress control layer (8) above and / or below the decorative layer that is radio wave transparent; at least one light source (344, 444, 544); At least one optical waveguide optically connected to said light source (344, 444, 544); A decorative radome comprising: the optical waveguide is at least partially formed by the radio wave transparent substrate (321, 421, 521) located adjacent to and / or in contact with the radio wave transparent decorative coating (324, 424, 524), and light from the light source (344, 444, 544) is coupled into the radio wave transparent substrate (321, 421, 521) in a direction perpendicular to a normal direction of at least a portion of the first surface (422) and / or the second surface (423); the radio wave transparent substrate (321, 421, 521) comprises a relieved portion (325, 425) formed by a recess in the second surface (423), preferably towards the opposite surface, and / or a raised portion of the radio wave transparent substrate (321, 421, 521); In particular, said decorative layer (324, 424, 524) is at least partially applied to said relieved portions (325, 425) and / or said raised portions, the light is guided through the radio wave transparent substrate (321, 421, 521), and in the mitigated portion (325, 425), the light is at least partially reflected / scattered by the radio wave transparent decorative coating (324, 424, 524) towards an observer (342); A decorative radome, wherein the overall residual stress of said radio wave transparent decorative coating (324, 424, 524) is tensile.

2. The decorative radome of claim 1 , wherein the light source (344, 444, 544) is located at least partially at a side edge of the radome behind a support structure of the radome.

3. the radio wave transparent decorative coating (324, 424, 524) is a first surface radio wave transparent decorative coating located at least partially on the first side of the radio wave transparent substrate (321, 421, 521); or the radio wave transparent decorative coating (324, 424, 524) is a second surface radio wave transparent decorative coating at least partially located on the second side of the radio wave transparent substrate (321, 421, 521); The decorative radome of claim 1 , wherein the radio wave transparent decorative coating (324, 424, 524) is at least partially covered with an overmold layer (326, 426, 526).

4. 4. The decorative radome of claim 3, wherein the overmold layer (326, 426, 526) comprises a radio wave transparent polymer and / or is located on a side of the radio wave transparent decorative coating (324, 424, 524) facing away from the radio wave transparent substrate (321, 421, 521).

5. The decorative radome according to any one of claims 1 to 4, wherein the radio wave transparent substrate (321, 421, 521) is masked to limit the area of application of the decorative layer (324, 424, 524) to only a portion of the second surface (423) of the radio wave transparent substrate (321, 421, 521).

6. 2. The decorative radome according to claim 1, wherein the radio wave transparent substrate (321, 421, 521) is a molded substrate (321, 421, 521) preferably comprising polycarbonate that is transparent to visible light, and the radio wave transparent substrate (321, 421, 521) is provided in particular in a first-shot molding step.

7. 7. The decorative radome according to claim 6, wherein a visual feature, in particular in the form of a logo, is provided on the radio wave transparent substrate (321, 421, 521), in particular in the area of the mitigated portion (325, 425), and wherein the logo is formed by the radio wave transparent decorative coating (324, 424, 524), which is radar / radio wave transparent and reflective to visible light, and which comprises in particular AlGe provided by a PVD coating process.

8. 8. A decorative radome according to any one of claims 1 to 7, wherein the radio wave transparent substrate (321, 421, 521) and the radio wave transparent decorative coating (324, 424, 524) are overmolded by an overmolding layer (326) that is opaque to visible light but radio wave / radar transparent, preferably the overmolding layer (326) is provided in a second shot molding step and / or comprises an AES material, in particular a dark-colored AES.

9. 9. The decorative radome of claim 8, wherein the overmolding layer (326) encapsulates the radio wave transparent decorative coating between the radio wave transparent substrate (321, 421, 521) that is transparent to visible light and the overmolding layer (326) that is opaque to visible light.

10. (i) said radio wave transparent substrate (321, 421, 521) is protected by a second surface coating in the form of a hard coat (328), in particular a thermal hard coat; and / or (ii) the radome is adapted for a radio wave transmitter / receiver, in particular comprising a radar unit (340), arranged on opposite sides of the radome, and the illumination system of the radome comprises two light sources (344), in particular comprising LEDs, by which a light beam (346) is coupled into the radio wave transparent substrate (321, 421, 521), which also acts as an optical waveguide so that light is coupled from the light source (344) into the optical waveguide; 10. The decorative radome according to claim 6, wherein the light source (344) also partially forms part of the illumination system, and wherein the light source (344) represents an edge lighting source since the light is coupled into the light guide in the form of the radio wave transparent substrate (321, 421, 521) in a direction that is mainly perpendicular to the normal direction N of the surface of the radio wave transparent substrate (321, 421, 521), and wherein the light relief portion (325) in the radio wave transparent substrate (321, 421, 521) is designed obliquely.

11. 2. The decorative radome according to claim 1, wherein the light of the two light sources (444) in the form of light rays (446) is coupled into the radio wave transparent substrate (321, 421, 521), and the radio wave transparent substrate (321, 421, 521) acts as an optical waveguide since the light rays within the radio wave transparent substrate undergo internal reflection, as a result of which the light is not significantly scattered out of the radio wave transparent substrate (321, 421, 521) and is guided along the radio wave transparent substrate (321, 421, 521) until it falls on the radio wave transparent decorative coating (324, 424, 524) in the mitigation portion (325, 425), from which the light is reflected and / or scattered out of the radio wave transparent substrate (321, 421, 521) to be seen by the observer.

12. The decorative radome according to any one of claims 1 to 11, wherein said at least one light source (344, 444, 544) comprises at least one LED, at least one laser, and / or at least one light source array.

13. A radar system comprising a radio wave transmitter, a radio wave receiver, and a decorative radome according to any one of claims 1 to 12.

14. An automotive emblem comprising a decorative radome according to any one of claims 1 to 12.

Images