Radome

Abstract

The present invention relates to a radome (10) designed to cover a vehicle radar, said radome comprising: a first plastic component (1); a second plastic component (2); at least one interface (4) formed between the first plastic component (1) and the second plastic component (1), the first plastic component (1) being connected to the second plastic component (2) at the interface (4) by injection moulding; and a radar region (7) which is designed for the transmission of radar radiation from the vehicle radar, the at least one interface (4) being arranged at least partially in the radar region (7).

Description

[0001] Radome

[0002] 1. Field of technology

[0003] The present invention relates to a radome for covering a vehicle radar and a method for its manufacture.

[0004] 2. State of the art

[0005] Modern motor vehicles are equipped with a multitude of sensors that record and process information about the vehicle's surroundings, and transmit it to control units. In addition to optical systems such as cameras and LIDAR (Light Detection and Ranging) and acoustic systems such as ultrasound for short ranges, such as in parking sensors, radar sensors (radio detection and ranging) are installed, particularly in the front and rear areas. Radar sensors emit modulated electromagnetic waves whose wavelengths in the automotive sector are around 24 GHz and in the 77-79 GHz band. The radar signals are reflected by other vehicles, pedestrians, cyclists, or objects at the side of the road, and the reflections are received by the emitting sensor. This calculates a list of detected targets with direction and distance information from the reflections and sends this to connected control units.In this way, driver assistance systems such as adaptive cruise control (ACC), emergency braking assistants, lane departure warning systems or autonomous driving functions can be supported.

[0006] Radar signals are usually transmitted by an antenna array. The individual antennas of the array are controlled with different amplitudes and phases so that the radar signals leave the sensor in a preferred direction and the reflected signals are also received in preferred directions. By temporally controlling the amplitude and phase, a defined angular range in front of, and possibly behind and to the side of, the vehicle can be scanned.

[0007] To protect radar sensors, but also for optical reasons, radar sensors in motor vehicles are often covered with a radome or installed behind existing vehicle parts such as bumpers. A radome is a cover that, on the one hand, provides a radar sensor with the necessary protection from dust, dirt, water, stone chips, etc., and, on the other hand, allows the most unhindered transmission of radar radiation. This applies both to the overall amplitude attenuation and the directional dependence of the attenuation. On the one hand, it is desirable that the overall amplitude is attenuated as little as possible, since the radar beams pass through the radome twice: when emitting and when receiving the reflected signals.On the other hand, the angular dependence of the attenuation must remain below a low tolerance threshold, otherwise the direction of a radar target can no longer be determined with sufficient accuracy. Furthermore, inhomogeneities in the radome can make reliable target detection impossible or result in nonexistent radar targets (ghost targets). Inhomogeneities are evident in locally strongly varying radar transmissions, which can lead to refraction or scattering of the radar waves, similar to a crack or break in a pane of glass or an air pocket in water ice.

[0008] ,2. Summary of the invention

[0009] The object of the present invention is therefore to provide a radome for motor vehicle radars which, on the one hand, is visually appealing and, on the other hand, meets the requirements of modern radar systems with regard to radar transmission and is also cost-effective to manufacture.

[0010] This object is achieved by a radome according to claim i. Advantageous embodiments are the subject of the dependent claims. The radome according to the invention is designed to cover a vehicle radar and has a first plastic component and a second plastic component. Furthermore, the radome has at least one interface formed between the first plastic component and the second plastic component, wherein the first plastic component is connected to the second plastic component at the interface by injection molding. Furthermore, the radome has a radar region which is designed to transmit radar radiation from the vehicle radar, wherein the at least one interface is arranged at least partially in the radar region.

[0011] The radome according to the invention is designed to cover a vehicle radar. This means that during normal operation of the vehicle radar, the electromagnetic waves emitted by the radar pass through the radome both during transmission and during reception of reflected waves, and the electromagnetic waves are only affected within the specifications of the radar or vehicle manufacturer. This applies to both the total transmission and its angular dependence. The radome is thus approved by the vehicle or radar manufacturer for its intended purpose, namely use as a cover for a vehicle radar.

[0012] The radome according to the invention further comprises a first and a second plastic component. These are therefore sections or parts of the radome that can be at least visually demarcated from one another and which comprise the two different plastic components. The two plastic components meet at at least one interface. The interface thus separates the first plastic component from the second plastic component and delimits the two from one another. A radome according to the invention can in principle have several such interfaces, but at least one. For example, the first component and / or the second component could be present in more than one demarcated region of the radome, resulting in several interfaces. If there are several interfaces, the following description with regard to the at least one interface applies accordingly to the other interfaces.

[0013] The at least one interface can be arranged at any angle to a surface of the radome. For example, the interface can be perpendicular to the surface or inclined to it. The angle can also change along the interface. The invention allows for considerable design flexibility here without negatively affecting the radar transmission of the radome.

[0014] The two plastic components meet at the interface. They form a bond by injection molding. Both components are manufactured and bonded together in a single injection molding process. This constitutes a multi-component injection molding process, or at least a two-component injection molding process. This eliminates the need for adhesives, adhesion promoters, or similar materials at the interface, which would be detrimental to radar transmission. The connection between the components is based purely on chemical bonding forces generated by the plastic components themselves.

[0015] Furthermore, the radome has a radar range which is designed for the transmission of radar radiation from the vehicle radar. As explained above, all specifications of the vehicle or radar manufacturer with regard to the transmission of electromagnetic radar signals are met within the radar range. This means, on the one hand, that the overall transmission is not significantly impaired and, on the other hand, that the angular dependence of the transmission is not significantly distorted. The radar range is therefore essential for the operation of a radar covered by the radome. Preferably, the radar range is a partial area of ​​the radome. In this way, fastening devices such as screw holes, clamps, springs or the like can be located outside the radar range in order to mount the radome on the vehicle in front of the radar. According to the claim, the at least one boundary surface is also arranged at least partially in the radar range.The inventors realized that this approach allows for the design of a visually appealing radome that, for example, is not recognizable as such. Although there is an interface between the two plastic components in the radar area, the injection molding process used to join the two plastic components avoids inhomogeneities at the interface. Furthermore, additional connecting components such as adhesives, bonding agents, or the like, which themselves cause inhomogeneities and may have a different radar transmission than the plastic components, are eliminated.

[0016] Although the interface between the two plastic components lies within the radar range, radar transmission is not significantly impaired. This provides design freedom for the radome, allowing the radome function to be concealed, for example, as an existing vehicle component. The injection molding technology used also enables cost-effective and visually appealing production, compared to, for example, foils as design elements.

[0017] The first plastic component can be chemically bonded to the second plastic component at at least one interface. For example, the chemical bond can be a result of injection molding. Due to the purely chemical bond, adhesives, adhesion promoters, and the like can be dispensed with.

[0018] The first plastic component can comprise color pigments of a first type, wherein the second plastic component can comprise color pigments of a second type which is different from the first type, wherein preferably the first plastic component does not comprise any color pigments of the second type and the second plastic component does not comprise any color pigments of the first type. In this way, the two plastic components can be visually distinguished from one another and the radome can be designed to be visually appealing. For example, the first type of color pigments can be white color pigments and the second type of color pigments can be black color pigments. It is also possible for one plastic component to contain color pigments but the other plastic component not.

[0019] In one embodiment of the invention, the color pigments of the first type and the color pigments of the second type are not metal-based color pigments. Metals can be detrimental to radar transmission, weakening it overall and / or causing undesirable directional deviations. By omitting metal pigments, radar transmission is not significantly impaired.

[0020] The radome can have a substantially constant thickness in the radar range. This minimizes the angular dependence of radar transmission.

[0021] The radome can have a third plastic component, as well as at least one second interface formed between the third plastic component and the first plastic component, wherein the at least one second interface is arranged at least partially in the radar range; furthermore at least one third interface formed between the third plastic component and the second plastic component, wherein the at least one third interface is arranged at least partially in the radar range. In principle, any number of plastic components can be used within the scope of the present invention, but at least two. A third component considerably expands the design freedom for the radome. The three components can be joined together in a single three-component injection molding process.

[0022] The third plastic component can cover the first plastic component and the second plastic component, forming a cover layer for the radome. This allows the radome itself to be provided with a protective layer. Depending on the radome design, the third component can also serve as a carrier layer for the first and second plastic components on the rear side, i.e., the side facing the radar.

[0023] The third plastic component can be transparent. This significantly expands the optical design options, as the first and second components appear to be cast into the transparent cover layer. On the other hand, a transparent cover layer serves as a seal and thus prevents dirt from accumulating on structures formed by the first and second plastic components. Finally, the first and second components can be designed with different thicknesses for optical reasons, which are compensated for by the transparent cover layer so that the radome as a whole has a substantially constant thickness in the radar range.

[0024] The top layer can have a thickness of 1-3 mm. The inventors have determined that this range is optimal for the protective function and, at the same time, creates a positive visual impression.

[0025] At least one of the plastic components can be polymethyl methacrylate (PMMA). PMMA is a non-exclusive example of a plastic suitable for the invention; it is easy to process by injection molding and meets the radar transmission requirement. The invention is not limited to PMMA. Other plastics are possible.

[0026] The interfaces in the radar range cannot contain any gas inclusions. Gas inclusions lead to inhomogeneities and can make use as a radome impossible. By using a multi-component injection molding process to join the plastic components, gas inclusions can be effectively avoided.

[0027] The radome can have at least one injection point located outside the radar range. Injection points are necessary for injecting the plastics forming the plastic components into the injection molding cavities. These are usually openings in a cavity or in a counterpart that closes the cavity. The openings usually leave tactile and visible features in the finished plastic component, namely so-called injection points. By locating these points outside the radar range, any influence of the injection points on the transmitted radar waves is avoided.

[0028] The radome can be an emblem. An emblem is understood to mean a decoration, a logo (e.g. of a vehicle manufacturer), a model designation or similar. The vehicle manufacturer's logo in particular is often affixed to the front of a vehicle, e.g. on, below, or above the radiator grille. According to the invention, due to the use of a multi-component injection molding process, it is possible to arrange the interface between two plastic components freely, in particular within the radar range, without significantly impairing radar transmission (at least within vehicle manufacturer or manufacturer's limits).

[0029] This allows vehicle manufacturer logos to be replicated that also function as a radome, even though the latter function is not apparent. The radar is essentially hidden behind the vehicle manufacturer logo. The use of a multi-component injection molding process allows for the cost-effective and visually appealing production of such radome-capable logos.

[0030] A further aspect of the present invention relates to a method for producing a radome as described herein, comprising the steps of: injecting the first plastic component into a first cavity; transferring the injected plastic component into a second cavity; injecting the second plastic component into the second cavity so that the interface between the first plastic component and the second plastic component is formed.

[0031] Preferably, the steps are performed in the order mentioned. Everything stated with regard to the radome according to the invention, in particular its advantages, applies accordingly to the manufacturing process.

[0032] 4. Brief description of the drawings

[0033] The present invention is explained below using preferred embodiments with reference to the drawings. The drawings show:

[0034] Fig. 1A: An embodiment of a radome according to the invention.

[0035] Fig. 1B: A section through the embodiment of Fig. 1A.

[0036] Fig. 2A: A design drawing of the embodiment of the

[0037] Figures 1A and 1B in an oblique view.

[0038] Fig. 2ß: A top view of the radome of Fig. 2Ä.

[0039] Fig. 2C: A section through the radome of Fig. 2ß along the line AA.

[0040] 5. Detailed description of preferred embodiments

[0041] In the following, only a few possible embodiments of the invention are described in detail. However, the present invention is not limited to these, and a variety of other embodiments are conceivable without departing from the scope of the invention. The presented embodiments can be modified and combined with one another in many ways whenever they are compatible, and certain features can be omitted where they appear unnecessary. In particular, the disclosed embodiments can be modified by combining certain features of one embodiment with one or more features of another embodiment. While the following embodiments are described primarily with reference to a radome, those skilled in the art will recognize that the method for manufacturing a corresponding radome likewise benefits from the aforementioned features and advantages.

[0042] Throughout the present figures and description, the same reference numerals refer to the same elements. The figures may not be to scale, and the relative size, proportions, and representation of elements in the figures may be exaggerated for clarity, illustration, and convenience, and may vary accordingly in other embodiments of the invention.

[0043] Fig. 1A shows a Radome io configured to mask a vehicle radar (not shown in the figures). This means that the radome influences the transmission of radar beams generated by a vehicle radar in front of which the Radome io is mounted, within the vehicle manufacturer's or radar manufacturer's specifications. In particular, the attenuation of radar transmission and the change in the beam angle remain below certain limits. Therefore, the Radome io is configured to fulfill its intended purpose, namely, on the one hand, to protect a vehicle radar, to optically conceal it, and, at the same time, to enable the vehicle radar to function properly during vehicle operation.

[0044] In the exemplary embodiment shown in Fig. 1A, the radome 10 comprises a first plastic component 1, a second plastic component 2, and a third plastic component 3. The invention is not limited to the presence of three plastic components. According to the invention, the radome comprises at least two plastic components. A different number, e.g., four or more plastic components, is possible.

[0045] In the embodiment of Fig. 1A, the plastic components 1, 2, and 3 comprise PMMA. PMMA is a non-exhaustive example of a plastic that can be used within the scope of the present invention. In other embodiments, other types of plastic can be used, and different types of plastic could be used within a single radome.

[0046] Furthermore, the radome 10 has at least one interface 4 formed between the first plastic component 1 and the second plastic component 2. An edge of this interface is shown in Fig. 1A, since the interface extends from the surface formed by the first and second plastic components 1 and 2 into the radome 10. In the sectional view of Fig. 1B, which shows the same exemplary embodiment as Fig. 1A, the interface 4 is shown in section within the radome 10. The interface 4 separates the first plastic component 1 from the second plastic component 2. In the exemplary embodiment of Fig. 1A, there is a single interface 4 between the first plastic component 1 and the second plastic component 2. In other exemplary embodiments, several interfaces can be formed, in particular when the plastic components form several mutually delimitable regions.

[0047] The first plastic component 1 is joined to the second plastic component 2 at the interface 4 by injection molding. During injection molding, plastic is plasticized, i.e., liquefied, in an injection molding machine in an injection unit and injected under pressure into an injection mold. An injection mold is formed, for example, by a mold and a corresponding counterpart that closes the mold. In the injection mold, the material returns to the solid state through cooling or a crosslinking reaction and is removed as a finished part after the injection mold is opened. The cavity of the mold, also referred to as the cavity, determines the shape and surface structure of the finished part. The radome 10 shown in Figures 1A and 1B is manufactured using a multi-component injection molding process. More precisely, it is a three-component injection molding process, which is also referred to as the 3K injection molding process for short.

[0048] Injection molding creates a permanent bond between the first

[0049] Plastic component 1 and the second plastic component 2 at interface 4. This is a chemical bond created by the pressures and temperatures encountered during injection molding. In particular, this prevents gas inclusions at the interfaces between the plastic components, which would impair radar transmission.

[0050] In the exemplary embodiment of Figures 1A and 1B, the second plastic component 2 is embedded in the first plastic component 1. The second plastic component 2 has the shape of an "X" within a circle. However, this shape is only exemplary, and in other embodiments, the plastic components can have any shape. For example, the second plastic component 2 could be in the shape of an automobile manufacturer's logo or it could be a model designation.

[0051] The first plastic component 1 comprises color pigments of a first type, and the second plastic component 2 comprises color pigments of a second type. In the exemplary embodiment of Figures 1A and 1B, the first plastic component 1 is black and the second plastic component 2 is white. In other exemplary embodiments, correspondingly different colors would be used. In particular, these types of color pigments are not metal-based and therefore do not affect radar transmission or only insignificantly.

[0052] In the exemplary embodiment of Figures 1A and 1B, the radome 10 additionally has a third plastic component 3. As already explained, two plastic components are sufficient according to the invention. The third plastic component 3 is transparent in this exemplary embodiment and covers the first plastic component 1 and the second plastic component 2 in the form of a cover layer. Because the third plastic component 3 is transparent, the first plastic component 1 and the second plastic component 2 are visible through the third plastic component 3. The cover layer 3 extends beyond the edge of the second plastic component 2.

[0053] Further interfaces arise between the plastic components, namely a second interface 5 between the third plastic component 3 and the first plastic component 1 and a third interface 6 between the third plastic component 3 and the second plastic component 2 (see Figures 1B and 2C). In other embodiments with more than three plastic components, correspondingly more interfaces might arise, and their number also depends on the number of unconnected subregions of the plastic components.

[0054] In other embodiments, the third plastic component can also be arranged not on the front side of the radome, but on its rear side, i.e., the side facing the radar. The third plastic component could then serve as a carrier layer for the other plastic components. In yet other embodiments, a plastic layer is arranged on the front side as a cover layer, and another plastic layer is arranged on the rear side as a carrier layer.

[0055] Figures 2A, 2B, and 2C show design drawings of the exemplary radome 10 from Figures 1A and 1B. As shown in Figures 2A and 2B, the radome 10 further comprises a radar region 7 configured for the transmission of radar radiation from the vehicle radar. A radome that influences the transmission of radar beams generated by a vehicle radar in front of which the radome is mounted within the vehicle manufacturer's or radar manufacturer's specifications therefore, by definition, comprises a radar region. In particular, the attenuation of the radar transmission and the change in the radiation angle within the radar region 7 remain below certain limit values. If radar beams outside the radar region 7 were to pass through the radome 10, this could potentially negatively influence the transmission.

[0056] In the embodiment of Figures 2A, 2B, and 2C, the radar range 7 is rectangular. In other embodiments, the radar range may have a different shape, for example, square, elliptical, or circular. The shape may depend on the specifications of the vehicle or radar manufacturer and / or on the type of radar to be covered. A radar that only resolves in the horizontal direction requires an elongated radar range, while a radar that also resolves in the vertical direction requires a more square or circular radar range.

[0057] In the exemplary embodiment of Figures 2A, 2ß and 2C, the radar area 7 has a size of 50 mm x 100 mm. In other exemplary embodiments, the radar area can have a different size. The size can depend on the specifications of the vehicle or radar manufacturer, the size of the radome, the radiation angle of the radar, the distance between the radar and the radome and other factors. The radar area can also have certain tolerances, i.e., in the specific installation situation, the radar beams may not completely fill the radar area 7, but only cover a smaller portion of the radar area 7, i.e., radiate through it.

[0058] As shown in Figures 2A and 2B, at least one interface 4 is at least partially arranged in the radar region 7. In the exemplary embodiment, this is the interface 4 between the first plastic component 1 and the second plastic component 2. Since the third plastic component 3 lies in the form of a cover layer over the first plastic component 1 and the second plastic component 2, parts of the interface 5 between the third plastic component 3 and the first plastic component 1, as well as parts of the interface 6 between the third plastic component 3 and the second plastic component 2 are also arranged in the radar region 7 (cf. Fig. 1B).

[0059] In the exemplary embodiment of Figures 2A and 2B, the boundary surfaces 4, 5, and 6 extend both within and outside the radar range 7. In other exemplary embodiments, boundary surfaces may also extend entirely within the radar range, ie, these boundary surfaces would not extend outside the radar range. According to the invention, however, at least part of a boundary surface extends within the radar range.

[0060] Fig. 2B shows the radome 10 of the exemplary embodiment in a plan view, and Fig. 2C shows a section along line AA in Fig. 2B. As shown in Fig. 2C, the radome 10 has a substantially constant thickness in the radar area 7. On the one hand, the thickness must not be too large so as not to unduly impair radar transmission, and on the other hand, it must not be too thin so that the radome is sufficiently stable and can protect the underlying radar.

[0061] As shown in Figures 2A and 2ß, the radome 10 of the exemplary embodiment has two so-called injection points 8a and 8b. Injection points are necessary to inject the plastics forming the plastic components 1, 2, 3 into the injection molding cavities. These are usually openings in a mold or in a counterpart that closes the mold. The openings generally leave tactile and visible features in the finished plastic component, namely the aforementioned injection points. In the exemplary embodiment, the injection points 8a and 8b are arranged outside the radar area 7. This prevents the injection points 8a and 8b from influencing the transmitted radar waves.

[0062] In other embodiments, the radome 10 has more or fewer than two injection points. This may depend on the design of the radome 10, the plastics used, particularly their flow properties, and process parameters.

[0063] Also, in other embodiments, the radome may have fastening devices outside the radar range, such as screw holes, clamps, springs, or the like, to mount the radome on the vehicle in front of the radar.

[0064] As already explained, the radome 10 of the embodiment shown in the figures is manufactured using a three-component injection molding process. Here, the first plastic component 1 is injected into a first cavity under pressure and heat at the injection points already explained. The first cavity can be formed by a mold and a corresponding counterpart that closes off the mold. The first cavity thus defines the shape of the first plastic component 1. The injected first plastic component 1 is then transferred into a second cavity, i.e. removed from the first cavity and inserted into the second cavity. For this purpose, the first plastic component 1 can remain in the mold, which is moved from a first counterpart that closes off the first cavity to a second counterpart that closes off the second cavity.

[0065] The second cavity formed by the mold and the second counterpart is larger than the first cavity, as it contains the space required for the second plastic component 2. The second plastic component 2 is then injected into the second cavity at the injection points already explained and chemically bonds with the first plastic component i, which is already in the mold.

[0066] Finally, the mold with the first and second plastic components 2 is transferred a second time onto a third counterpart, which, together with the mold, forms a third cavity, which in turn has a cavity for the third plastic component 3 to be injected. The third plastic component 3 is then injected into the cavity at the injection points already explained and chemically bonds with the first and second plastic components. In embodiments with two plastic components, these steps—namely, transferring to the third counterpart and injecting the third plastic component—would be omitted. With more than three components, there would be correspondingly more transfer and injection steps.

[0067] After the final injection step, the finished radome 10 is removed from the mold and cooled if necessary. Post-processing steps may follow.

[0068] Everything said with regard to the radome according to the invention, in particular its advantages, applies accordingly to the manufacturing process described.

Claims

Claims 1. Radome (io) configured to cover a vehicle radar, comprising: a first plastic component (i); a second plastic component (2); at least one interface (4) formed between the first plastic component (1) and the second plastic component (1), wherein the first plastic component (1) is connected to the second plastic component (2) at the interface (4) by injection molding; a radar region (7) configured to transmit radar radiation from the vehicle radar, wherein the at least one interface (4) is at least partially arranged in the radar region (7).

2. Radome (10) according to claim 1, wherein the first plastic component (1) is chemically bonded to the second plastic component (2) at the at least one interface (4).

3. Radome (10) according to one of claims 1-2, wherein the first plastic component (1) comprises color pigments of a first type, wherein the second plastic component (2) comprises color pigments of a second type which is different from the first type, wherein preferably the first plastic component (1) does not comprise any color pigments of the second type and the second plastic component does not comprise any color pigments of the first type.

4. Radome (10) according to claim 3, wherein the color pigments of the first type and the color pigments of the second type are not metal-based color pigments.

5. Radome (10) according to one of claims 1-4, wherein the radome (10) has a substantially constant thickness in the radar region (7).

6. Radome (io) according to one of claims 1-5, further comprising: a third plastic component (3); at least one second interface (5) formed between the third plastic component (3) and the first plastic component (1), wherein the at least one second interface (5) is arranged at least partially in the radar range (7); at least one third interface (6) formed between the third plastic component (3) and the second plastic component (2), wherein the at least one third interface (6) is arranged at least partially in the radar range (7).

7. Radome (10) according to claim 6, wherein the third plastic component (3) covers the first plastic component (1) and the second plastic component (2) and forms a cover layer of the radome (10).

8. Radome (10) according to one of claims 6-7, wherein the third plastic component (3) is transparent.

9. Radome according to one of claims 6-8, wherein the cover layer has a thickness of 1-3 mm.

10. Radome (10) according to one of claims 1-9, wherein at least one of the plastic components (1, 2, 3) is polymethyl methacrylate, PMMA.

11. Radome (10) according to one of claims 1-10, wherein the boundary surfaces (4, 5, 6) in the radar area (7) do not have any gas inclusions.

12. Radome (10) according to one of claims 1-11, further comprising at least one injection point (8a, 8b) which is arranged outside the radar area (7). 13- Radome (10) according to one of claims 1-12, wherein the radome (10) is an emblem.

14. A method for producing a radome (10) according to any one of claims 1-13, comprising the steps: Injecting the first plastic component (1) into a first cavity; Transferring the injected plastic component (1) into a second cavity; Injecting the second plastic component (2) into the second cavity so that the interface between the first plastic component (1) and the second plastic component (2) is formed.

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