Window for radar environment detection and manufacturing method

Abstract

The present invention relates to a vehicle window (10) for radar environment detection, the vehicle window comprising: a window body (50) having an inner side (17) and an outer side (18), wherein the window body (50) comprises a plurality of radar waveguides (41, 41-1 to 41-n) for guiding radar radiation (100) from the inner side (17) to the outer side (18) and / or vice versa for guiding radar radiation from the outer side to the inner side, wherein the radar waveguides (41, 41-1 to 41-n) guide waves of the radar radiation (100) by means of a refractive index change. Furthermore, a method for manufacturing such a vehicle window (2) for radar environment detection is provided.

Description

Technical Field

[0001] The present invention relates to a vehicle window for improved radar environment detection and a method for manufacturing the same. In particular, the present invention relates to a windshield configured for use with a radar sensor that uses a plurality of distributed radar transmit and receive sensors. Background Art

[0002] In the area of passive safety systems in motor vehicles and for levels 4 and 5 of autonomous driving, the distinguishability of road users is of particular importance for protecting passengers and other road users. For this purpose, safe environment detection is required. To ensure this environment detection, the surroundings of the motor vehicle must be detected in all three spatial dimensions with the highest possible resolution. Modern cameras and LIDAR systems are able to ensure environment detection, but are affected in their quality or fail completely in poor visibility conditions, such as in fog, snow or darkness. In contrast, radar sensors are not subject to these limitations, but must be arranged as an array with a large number of sensors to achieve high-resolution three-dimensional imaging.

[0003] Furthermore, the individual sensors in such an array must be synchronized in terms of their transmission and reception times. This synchronization is extremely technically demanding. Therefore, it is advantageous for the individual radar sensors to be as small, simple, flexible, fault-tolerant, robust and inexpensive as possible. For this purpose, as little electronics as possible should be installed in the radar sensor itself, and digital data processing should be centralized within a central control unit.

[0004] It is known from the prior art that radar systems are installed behind the windshield and the radar systems radiate and receive radar waves through the windshield.

[0005] EP 2 808 698 A2 shows a system in which the windshield has a metallization layer to prevent infrared radiation from entering the vehicle interior. Since the metallization layer blocks radar radiation, there are cutouts in front of the radar system.

[0006] To achieve high resolution in azimuth and elevation, a large number of sensors are required. In known vehicles, the arrangement and operation of these sensors in the motor vehicle have not yet been satisfactorily solved so that the desired high resolution can also be achieved for imaging or image processing methods. Summary of the Invention

[0007] The technical problem here is how the arrangement of a plurality of sensors can be achieved, and in particular the operation of a plurality of radar sensors in a vehicle with improved transmission and reception characteristics.

[0008] The technical problem is solved according to the invention by a window for radar environment detection and a method for manufacturing a window.

[0009] The invention is based on the concept that the window is constructed with a plurality of radar waveguides through which radar radiation or radar waves are improvedly transmitted through the window during radar sensor transmission and radar sensor reception. Here, the radar waveguides are realized by a change in the refractive index in the window's form. It is generally known that electromagnetic radiation or electromagnetic waves propagating in a first medium with a first refractive index are completely or almost completely reflected when contacting the boundary surface with a second medium having a smaller refractive index than the first medium at an angle exceeding a preset angle measured with respect to the surface normal on the boundary surface.

[0010] Accordingly, there is provided in particular a window for radar environment detection, the window including a form having an inner side and an outer side, wherein the form includes a plurality of radar waveguides for guiding radar radiation from the inner side to the outer side and / or vice versa for guiding radar radiation from the outer side to the inner side, wherein the radar waveguides achieve the guiding of the waves of the radar radiation by a change in the refractive index.

[0011] A method for manufacturing a window for radar environment detection, the method including the steps of manufacturing or providing a form having an inner side and an outer side, wherein a plurality of radar waveguides are constructed in the form for guiding radar radiation from the inner side to the outer side and / or vice versa for guiding radar radiation from the outer side to the inner side, wherein the radar waveguides achieve the guiding of the waves of the radar radiation by a change in the refractive index.

[0012] The radar waveguides can be constructed in the form by a change in the refractive index in the material of the form, and the form is preferably a windshield. This enables very good integration into the window, and this integration does not impair the mechanical stability of the window. Thus, in an embodiment, the refractive index change of at least one of the plurality of radar waveguides is constructed by refractive index modulation in the material of the form.

[0013] Constructing the radar waveguides by a change in the refractive index in the material of the form can be achieved by local changes in the form material during form manufacturing.

[0014] A particularly advantageous embodiment provides that the refractive index change of at least one of the plurality of radar waveguides is constructed by refractive index modulation in the material of the form.

[0015] In an embodiment, refractive index modulation is designed by means of a non-linear multi-photon process, thereby providing one or more radar waveguides. For this purpose, for example, the focus of a focused laser moves in the volume of the material of the window. In the focus of the laser radiation, due to the non-linear multi-photon process, the refractive index of the material changes locally. By moving the focus in the material to different positions, the refractive index in the material can be locally changed in a targeted manner. The density of the material is locally changed by the multi-photon process, and thereby the refractive index is changed.

[0016] It is feasible here to provide different spatial structures of the refractive index change. Thus, it is feasible that at least one radar waveguide or at least another radar waveguide among a plurality of radar waveguides has a horn antenna structure.

[0017] Preferably, all radar waveguides among the plurality of radar waveguides have a horn antenna structure. Thereby, the emission of radar radiation through each optical waveguide is significantly improved. In addition, the wave guiding of the reflected radar radiation guided from the outside to the inside of the window is also improved.

[0018] Other embodiments may have other structures that facilitate the emission of radar radiation or the reception and further guiding of radar radiation to the sensor. Thereby, as in the case of a horn antenna-like structure, the emission characteristics of the emitted radar radiation and the reception characteristics of the sensor coupled to the radar waveguide can be affected.

[0019] In order to be able to make full use of the polarization of the emitted and received radar radiation to detect the surroundings, a single, multiple, or all radar waveguides are configured such that they facilitate the emission of radar waves or radar radiation having a specific polarization direction. Here, the polarization direction of the radiation emitted at a certain distance from the outer side of the window, i.e., in the far field of the radar radiation, is decisive. Here, it can be linearly polarized radar radiation, and the polarization direction of the radar radiation is spaced from the window to indicate the polarization direction of the corresponding radar waveguide.

[0020] Therefore, the polarization direction that can be assigned to each radar waveguide can be described with respect to a coordinate system fixedly coupled to the window of the vehicle window.

[0021] In addition to preferably guiding radar waves or radar radiation having a linear polarization direction when output from the outer side of the window, it is also possible to facilitate the guiding of circularly polarized radar waves or circularly polarized radar radiation or radar radiation polarized in a different manner.

[0022] In order to be able to take into account the polarization of the radar radiation and its change during reflection when measuring the environment, it is stipulated in an embodiment that some of the radar waveguides among the plurality of radar waveguides respectively promote different polarizations of the radar radiation output from the outer side of the window and / or entering during wave guiding.

[0023] Particularly preferably, this applies to radar waveguides that are adjacent to each other in a plurality of radar waveguides. This means that when a plurality of radar waveguides are arranged in a spatial direction, the radar waveguides that are adjacent to each other in pairs respectively promote radar waves or radar radiation with different polarization directions in the waveguide. However, preferably, the condition that the plurality of radar waveguides have different polarization directions in pairs respectively applies to all the radar waveguides in the plurality of radar waveguides, which means that these radar waveguides respectively promote very good polarization directions of the radar radiation emitted or received in the waveguide, and all the very good polarization directions are different.

[0024] In order to improve the evaluation of the radar waves or radar radiation emitted and transmitted through different radar waveguides and obtain a high environmental resolution, a time correlation between the emission time points and the reception time points of different radar waveguides is required. This means that, for example, the emission of radar radiation through different radar waveguides should be carried out synchronously in time, that is, in a coordinated manner in time. Especially when the radar radiation emitted and received by each radar waveguide is generated and detected by a radar chip that is separately coupled to each radar waveguide, the distance between the radar waveguides can be advantageously known and regularly measured.

[0025] For this purpose, it is stipulated in an embodiment that the radar waveguides of at least one group among the plurality of radar waveguides are directly or indirectly connected to each other through a calibration waveguide among the plurality of calibration waveguides.

[0026] Therefore, the window advantageously includes a plurality of calibration waveguides, wherein each calibration waveguide is configured for guiding radar radiation based on total reflection at least between two radar waveguides connected by the corresponding calibration waveguide, and a part of the radar radiation that enters one of the interconnected radar waveguides on the inner side of the window body exits from the other radar waveguide of the interconnected radar waveguides on the inner side of the window body, or vice versa.

[0027] An embodiment of the present invention stipulates that the adjacent radar waveguides of at least one group of radar waveguides are respectively connected to the calibration waveguide.

[0028] Preferably, the calibration waveguide is configured such that the radar signal of the radar chip coupled to each radar waveguide in the group (if through the radar waveguide) is emitted as the only radar signal, and all other radar chips coupled to one of the radar waveguides in the group obtain a "direct signal" through the calibration waveguide, and these other radar chips can synchronize the received radar radiation reflected in time according to this signal. That is to say, in terms of the transmission of radar radiation, the radar waveguides are all interconnected.

[0029] In a preferred embodiment, the calibration waveguide is formed by guiding the focus of a laser in the material of the window body for a refractive index change formed by non-linear multi-photon interaction.

[0030] It is also possible to construct a calibration waveguide by local variation of the material in the window manufacture. Thus, the material for guiding the radar radiation is surrounded by a material having a higher refractive index.

[0031] In other embodiments, a calibration waveguide is constructed by adding a polymer material to the window.

[0032] The radar waveguide can also be partially or entirely constructed of a polymer material, which is added to the void portion of the window. Thus, the embodiment provides that at least some of the radar waveguides are constructed of a polymer material, which is added to the void portion of the window.

[0033] In particular, in order to minimize the coupling and decoupling losses on the outer side of the window and, if necessary, also as protection of the optical waveguide, it is provided in some embodiments that the radar waveguide among the plurality of radar waveguides is covered on the outer side of the window by at least one antireflection layer, the layer thickness of which is an integer multiple of a quarter of the radar wavelength provided for wave guiding in the antireflection layer. The window is thus coated on the outer side, at least in the region of the radar waveguide, with a corresponding antireflection layer.

[0034] The antireflection layer is preferably adapted to the refractive index in order to minimize the reflection of the radar radiation when leaving / entering the window. This means that the refractive index is adapted to the wavelength of the radar radiation, i.e., a material having a correspondingly required refractive index is selected in the wavelength of the radar radiation, or the refractive index of the material of the antireflection layer is adjusted accordingly for the wavelength of the radar radiation by material addition, so that the transmittance of the radar radiation is optimal. Thus, tuning (Vergütung) for the radar wavelength occurs.

[0035] Other embodiments may provide that the antireflection layer is constructed in multiple layers in order to significantly facilitate the coupling and decoupling of radar radiation of a specific wavelength or specific wavelength range with other wavelengths or wavelength ranges. Thereby, the reflection is minimized and thus the coupling and decoupling losses are significantly reduced. For this purpose, the refractive indices of the individual layers are preferably selected and determined by simulation calculations.

[0036] Other embodiments and / or extensions may provide that the material layer thicknesses of the layers are alternatively or additionally included in the simulation.

[0037] The following embodiment has proven to be particularly advantageous, namely, at least one group of the radar waveguides among the plurality of radar waveguides are arranged equidistantly from each other. Preferably, the at least one group of radar waveguides are arranged in a straight line.

[0038] In order to visually hide a radar chip coupled to a radar waveguide from a human observer, especially when observing the window from the outside, in some embodiments, it is stipulated that the window in the area of a plurality of radar waveguides is configured to be opaque in the visible wavelength range by means of an imprint in the visible wavelength range. In such an embodiment, advantageously, a plurality of radar waveguides are arranged in the black imprint area of the window. Description of the Drawings

[0039] The present invention will be described in detail below with reference to the drawings. In the drawings:

[0040] Figure 1 A front view of a vehicle with radar-based environmental detection is shown; and

[0041] Figure 2 A cross-sectional view of a window with two enlarged screenshots is shown, one showing a radar waveguide on the outside of the window and the other showing a radar waveguide on the inside of the window. Detailed Description of the Embodiments

[0042] Figure 1 A front view of a vehicle 1 is schematically shown. The vehicle includes an environmental detection system 5. The environmental detection system 5 includes at least one radar device 30. In the illustrated embodiment, the radar device 30 has a plurality of radar chips 31-1 to 31-n, which can respectively generate and detect radar radiation. In a preferred embodiment, the radar signals detected by the respective radar chips 31-1 to 31-n are evaluated in a central evaluation device 33. For this purpose, the respective radar chips 31-1 to 31-n are coupled to the central evaluation device 33 via information lines 34-1 to 34-n in terms of information technology. The central evaluation device 33 provides environmental data 35 for further devices 7 of the vehicle 1. For example, this can be shown in a graphical form. The environmental data may include information about the position of an object relative to the vehicle 1, the relative speed of the object with respect to the vehicle, the relative speed with respect to other objects in the surrounding environment 2 of the vehicle 1, and the relative acceleration with respect to the vehicle 1 and / or with respect to other objects in the surrounding environment 2. However, the environmental data 35 may also include information about the absence of detected objects, i.e., free positions, in the surrounding environment 2 of the vehicle.

[0043] In Figure 1 the information lines 34-1 to 34-n are partially drawn outside the vehicle contour. However, it is to be understood by a person skilled in the art that the information lines 34-1 to 34-n are of course constructed inside the vehicle. Similarly, only the central evaluation device 33, the further device 7 and the communication connection 8, for example configured as a vehicle bus 9, are schematically shown. The device 7 can be any device that evaluates and / or uses the environmental data of the vehicle 1, such as a driver assistance system, a control device for autonomous driving, etc.

[0044] The re-adjustment of “-1, -2, -i, -m, -k, ... -n” should respectively distinguish similar objects, where n, i, k, and m are natural numbers.

[0045] The radar chips 31-1 to 31-n may or may not be equipped with antennas. The radar chips are arranged inside the vehicle 1, that is, behind the window 10. In this example, the window 10 is the windshield 11 that is configured as the window 10 of the motor vehicle 3. In the shown example, the radar chips 31-1 to 31-n are arranged on the upper edge 13, preferably in the area of the black mark 12. The black mark 12 is opaque in the visible wavelength range, so that when viewed from the outside, the radar chips 31-1 to 31-n arranged behind the windshield 11 are imperceptible or almost imperceptible to a human observer. The black mark 12 is preferably implemented such that it does not adversely affect the propagation of radar waves or radar radiation.

[0046] In order to minimize the radar radiation generated and emitted by the radar chips 31-1 to 31-n and the attenuation loss of the radar radiation 100' reflected back on the window, the window is configured with a plurality of radar waveguides 41-1 to 41-n. In the shown embodiment, there is exactly one radar waveguide 41-1 to 41-n for each radar chip 31-1 to 31-n respectively. In other embodiments, the number of radar waveguides 41 of the window 10 may be greater than the number of radar chips 31 arranged behind the window 10.

[0047] Figure 2 A cross-sectional schematic view through the window 10 is shown. The window 10 includes a window body 50. A plurality of radar waveguides 41-1 to 41-n are constructed in the window body 50. Preferably, these radar waveguides are arranged equidistantly. Preferably, the distance between adjacent radar waveguides 41-i, 41-i+1 is an integer multiple of the wavelength of the radar radiation used in the material of the window body.

[0048] Each waveguide 41 is coupled to one of the radar chips 31 on the inner side 17 of the window 10. The coupling is carried out such that the radar radiation 100 generated by the radar chip 31 is coupled to the corresponding radar waveguide as losslessly and with as little attenuation as possible. The radar radiation 100 is guided by the radar waveguide 31 through the window body 50 of the window 10 and is emitted into the surrounding environment 2 of the vehicle 1 on the outer side 18 of the window 10. A part of the emitted radar radiation 100 is reflected by an object (not shown) in the surrounding environment 2 of the vehicle 1. The reflected radar radiation 100' contacts the window 10 again, and at least part of it is coupled to the radar waveguide 41 as little lossily as possible, and is guided through the window 10 by the radar waveguide 41 to the inner side 17, and is decoupled there, so that the reflected radar radiation 100' can be detected by the radar chip 31, which is coupled to the corresponding radar waveguide 41.

[0049] It is to be understood that the radar radiation guided through one of the plurality of radar waveguides 31-1 to 31-n, i.e., radar waveguide 31-i, to the outside 18 of the window and emitted there (after being reflected) is guided through the window 50 not only from the radar waveguide 41-i, but also generally from the other radar waveguides 41-k (k≠i) to the correspondingly coupled radar chip 31-k.

[0050] The following briefly explains how to guide radar waves in the volume of a material that is transparent for a corresponding wavelength range. Glass and most transparent plastics are transparent not only in the visible wavelength range, but also in the radar wavelength range.

[0051] If it is possible to use the geometric image of the radiation passing through the volume of the material, then the material is transparent for the radiation in the volume. In particular, no scattering of the radiation occurs in the volume of the material, which, for example, causes diffusion streaks in the material in the case of radiation in the visible wavelength range.

[0052] At the interface between a first material with a first refractive index n1 and a second material with a refractive index n2, where the first refractive index n1 is less than the second refractive index n2, total reflection of the radiation occurs in the case of a flat angle of incidence of the radiation propagating in the first material. This property of total reflection can be used to form a waveguide. This property known from the visible wavelength range also exists in the radar wavelength range. Thus, a radar waveguide is a waveguide that can guide electromagnetic waves in the radar wavelength range or electromagnetic radiation propagating in a material based on reflection due to a refractive index change.

[0053] This is schematically shown in an enlarged screenshot A of the output region of one of the radar waveguides 14-1 on the outside 18 of the window 1.

[0054] The radar beam 101 of the radar radiation 100 propagating in the material 39 of the radar waveguide 41-1 with a refractive index m impinges on the material 59 of the window 50 with a refractive index n2 at a relatively flat angle. The radar beam 100 is reflected at the interface between the material 39 of the radar waveguide 41-1 and the material 59 of the window 50. Thereby, the guidance of the radar beam 101 and thus the wave of the radar radiation 100 occurs in the radar waveguide 31-1. The refractive index n2 is greater than the refractive index n1.

[0055] Thus, the radar radiation 100 generated in one of the radar chips in the radar chip 31 passes through the window 10 in a guided wave manner, such that the radar radiation 100 is coupled to the associated radar waveguide 41 on the inner side 17 of the window 10. In the material 39 of the radar waveguide 41, the radar radiation 100 is reflected at the interface with the material 59 of the window body 50 and is thus guided through the window 10 with low loss. On the outer side 18 of the window 10, the radar radiation 100 is output from the radar waveguide 41 and emitted into the surroundings 2 of the vehicle 1. There, the radar radiation 100' reflected on an object (not shown) is coupled to the radar waveguide 41 in the opposite direction on the outer side 18 of the window 2, is guided by reflection at the interface with the material 59 of the window body 50, and is decoupled from the radar waveguide 41 on the inner side 17 of the window 10 and guided to the radar chip 31 for detecting the reflected radar radiation 100'.

[0056] In order to reduce the reflection loss when the radar radiation 100 is output from the radar waveguide 41, the window 2 preferably has an anti-reflection layer 70 on the outer side 18. The material 79 of the anti-reflection layer 70 is preferably adapted to the wavelength of the emitted radar radiation 100 in the anti-reflection layer 70 with respect to the refractive index.

[0057] The layer thickness 72 of the anti-reflection layer 70 is equal to an integer multiple of a quarter of the wavelength λ of the radar radiation in the material 79 of the anti-reflection layer 70. If s is used to denote the layer thickness 72, then the following applies: s = mλ / 4, where m is a natural number.

[0058] The anti-reflection layer 70 can also be constructed in multiple layers, where each layer respectively has a layer thickness equal to an integer multiple of a quarter of the wavelength of the radar radiation in the corresponding layer material.

[0059] The radar waveguide 41 is shown, for example simplifiedly, in Figure 2 and particularly in the enlarged screenshot A. In a simple embodiment of the radar waveguide 41, it is assumed that the radar waveguide has a cylindrical shape. However, it is preferred that the optical waveguide 41 has a more complex structure, such as the structure of a horn antenna. This means that the refractive index change between the material of the radar waveguide and the material of the window body represents a more complex geometric structure in the volume of the window body. Thereby, the emission direction and beam characteristics of the emitted radar radiation 100 can be influenced. The polarization direction of the emitted radar radiation can also be influenced.

[0060] In Figure 2 the shown embodiment, the polarization direction 45-i of each radar waveguide 41-i of a plurality of radar waveguides is schematically shown, in which direction the radar radiation 100 is output from the respective radar waveguide 41-i on the outer side 18 of the window 10.

[0061] The polarization directions 45-1 to 45-n of the respective radar waveguides 41-1 to 41-n change gradually along the linear arrangement of the radar waveguides. The angular difference of the polarization directions between adjacent radar waveguides 41-i and 41-i+1 is thus constant. The polarization directions are shown in the plane of the drawing here, although the polarization directions relate to a plane perpendicular thereto.

[0062] If the radar waveguides 41 are configured such that they influence the polarization direction of the guided radar radiation 100, then polarization measurement can be implemented.

[0063] For the purpose of facilitating and / or enabling the evaluation of the individual detected radar signals of the reflected radar radiation 100' with high resolution, the calibration waveguides 81, 81-1 to 81-m are preferably constructed between the radar waveguides 41 on the inner side 17 of the vehicle window 10. For clarity, Figure 2 only one calibration waveguide 81 is shown. However, the calibration waveguides are correspondingly constructed between adjacent radar waveguides, as shown in the enlarged screenshot B. Each radar waveguide having two adjacent radar waveguides is coupled to its own, i.e., a total of two or more calibration waveguides, respectively, by means of these two adjacent radar waveguides.

[0064] The enlarged screenshot B shows two adjacent radar waveguides 41-i, 41-i+1, and their coupled radar chips 31-i, 31-i+1. The calibration waveguide 81-i is configured such that this calibration waveguide guides a part 100” of the radar radiation 100 coupled into the radar waveguide 41-i from the inner side 17 of the vehicle window 10 to the adjacent radar waveguide 41-i+1, so that at least a part 100” of the radar radiation guided by the calibration waveguide is detected by the radar chip 31-i+1.

[0065] Preferably, each radar waveguide 41-i is coupled to its directly adjacent radar waveguides 41-i-1, 41-i+1 by means of the calibration waveguides 81-i-1 and 81-i. Thereby, synchronization and calibration between the respective radar chips 31 can be achieved.

[0066] The radar waveguides 41 and the calibration waveguides 81 can be integrated into the vehicle window 10 in different ways.

[0067] In an embodiment, voids, such as through-holes in the vehicle window for the radar waveguides, are first constructed in the vehicle window. Subsequently, the voids are filled with a material having a refractive index n1 that is smaller compared to the refractive index n2 of the material of the vehicle window. For this purpose, a polymer material, for example, is suitable, which is added to the voids in the window body 50 of the vehicle window 10 made of glass.

[0068] The calibration waveguides 81 can also be manufactured in such a way that the voids in the window body 50 of the vehicle window 10 are filled with a polymer material.

[0069] It has proven to be particularly advantageous and flexible to fabricate the radar waveguide 41 and / or the calibration waveguide 81 by means of non-linear multi-photon processes. Using focused laser radiation, in a transparent material, the density of the transparent material and thus the refractive index can be locally changed in the focus of the laser radiation. By guiding the focus of the laser radiation through the volume of the form, complex refractive index changes can be introduced into the form, and thus the radar waveguide 41 and the calibration waveguide 81 can be constructed in this way. The properties of the radar waveguide 41 can be affected in various ways. Thus, the radar waveguide 41 can, for example, acquire a horn antenna structure, and / or their polarization properties can be adjusted and influenced.

[0070] A particular advantage is that the radar waveguide or the calibration waveguide can be placed with high precision into a finished vehicle window. Here, arbitrarily complex refractive index changes can be realized.

[0071] In the case of a suitably shaped void, by adding a material, in particular a polymer material, to the void of the form, the radar waveguide can be constructed with a horn antenna structure, and / or the polarization properties of the radar waveguide are adjusted.

[0072] Furthermore, the refractive index properties can already be locally changed during the fabrication of the form, and thus the radar waveguide or the calibration waveguide can be directly constructed during the fabrication of the form. For this purpose, it is desirable that the material of the radar waveguide is surrounded by a material with a higher refractive index.

[0073] The anti-reflection layer 70, which can be constructed in one or more layers, is preferably applied to the outer side of the form 50 over the entire surface. In order to avoid light refraction on the anti-reflection layer in the visible wavelength range, the anti-reflection layer 70 adapts the refractive index to the material 59 of the form 50. The multi-layer anti-reflection layer has a combination consisting of layers of different materials and thus different refractive indices in order to generate a phase jump at the boundary surface or transition and thus optimize the transmittance for radar wavelengths or for the wavelength range near the radar wavelength and, if necessary, for the angular range of the emission of radar radiation in the radar wavelength. The layer sequence is preferably determined by means of simulation calculations.

[0074] The radar waveguide 41 is highly precisely integrated into the vehicle window 10. Using the radar device 30 that uses the radar chip 31 in combination with the radar waveguide 41, a resolution of the surroundings 2 of the vehicle 1 can be achieved, which can be similar to the resolution of a LiDAR (Light Detection and Ranging) system.

[0075] If the radar waveguides are interconnected using calibration waveguides for time synchronization and calibration, then a particularly high resolution can be achieved.

[0076] In the embodiments described herein, the radar waveguide is configured along the upper edge 13 of the window 10 configured as the windshield 11. Additionally or alternatively, the radar waveguide can also be configured on the right edge 14, the left edge 15, and / or the lower edge 16 of the window. In principle, the radar waveguide can also be configured at other positions and is configured between calibration waveguides herein.

[0077] Particularly preferably, the window 2 is printed with an opaque color, such as black, in the area where the radar waveguide 41 is configured, in order to hide the radar chip 31 coupled to the radar waveguide 41.

[0078] In the described embodiment, the window 10 is the windshield 11. However, the window can also be any other window of the vehicle, such as the rear window, the side window, etc. In this case, the radar waveguide is configured adjacent to, for example, the A-pillar, the B-pillar, the C-pillar, and / or the upper or lower edge of the window.

[0079] The radar chips coupled to multiple radar waveguides can belong to one or different radar devices.

[0080] In the case of an inclined and / or curved window, the direction of wave guiding of the radar radiation in the radar waveguide may be different from the local surface normal of the window on the inner side and / or the outer side of the window. That is to say, in this case, the radar waveguide is not oriented perpendicular to the window.

[0081] List of reference numerals

[0082] 1 Vehicle

[0083] 2 Surroundings

[0084] 3 Motor vehicle

[0085] 5 Environment detection system

[0086] 7 Device

[0087] 8 Communication connection

[0088] 9 Vehicle bus

[0089] 10 Window

[0090] 11 Windshield

[0091] 12 Black marking

[0092] 13 Upper edge

[0093] 14 Right edge

[0094] 15 Left edge

[0095] 16 Lower edge

[0096] 17 Inner side

[0097] 18 Outer side

[0098] 30 Radar device

[0099] 31, 31-1 to 31-n Radar chips

[0100] 33 Central evaluation device

[0101] 34-1 to 34-n Information lines

[0102] 35 Environmental data

[0103] 39 Material of radar waveguide

[0104] 41, 41-1 to 41-n Radar waveguides

[0105] 45-1 to 45-n Polarization directions

[0106] 50 Window

[0107] 59 Material of window

[0108] 70 Anti-reflection layer

[0109] 72 Layer thickness

[0110] 79 Material of anti-reflection layer

[0111] 81 Calibration waveguide

[0112] 100 Radar radiation

[0113] 100’ Reflected radar radiation

[0114] 100” Part of coupled radar radiation

[0115] 101 Radar beam

Claims

1. A window (10) for radar environment detection, the window comprising: A window (50) having an inner side (17) and an outer side (18), characterized in that the window (50) comprises a plurality of radar waveguides (41, 41-1 to 41-n) for guiding radar radiation (100) from the inner side (17) to the outer side (18) and / or vice versa for guiding radar radiation from the outer side to the inner side, wherein the radar waveguides (41, 41-1 to 41-n) guide the waves of the radar radiation (100) by means of a refractive index change, wherein a plurality of calibration waveguides are provided, wherein each calibration waveguide is configured for guiding radar radiation based on total internal reflection at least between two radar waveguides (41, 41-1 to 41-n) connected by the respective calibration waveguide, and wherein a part of the radar radiation entering one of the interconnected radar waveguides (41, 41-1 to 41-n) on the inner side of the window exits from another one of the interconnected radar waveguides (41, 41-1 to 41-n) on the inner side of the window (50), or vice versa.

2. The window (10) according to claim 1, characterized in that A refractive index change of at least one of the plurality of radar waveguides (41, 41-1 to 41-n) is configured by refractive index modulation in the material (59) of the window (50).

3. The window (10) according to claim 2, characterized in that The refractive index modulation is designed by means of a non-linear multi-photon process.

4. The window (10) according to any one of the preceding claims, characterized in that At least one of the radar waveguides (41, 41-1 to 41-n) or at least another one of the plurality of radar waveguides (41, 41-1 to 41-n) has a horn antenna structure.

5. The window (10) according to claim 1, characterized in that Some of the plurality of radar waveguides (41, 41-1 to 41-n) respectively promote different polarizations of the radar radiation output from and / or entering the outer side of the window (10) during wave guiding.

6. The window (10) according to claim 1, characterized in that At least some of the radar waveguides (41, 41-1 to 41-n) are made of a polymer material which is added to the voids of the window (50).

7. The window (10) according to claim 1, characterized in that The radar waveguides (41, 41-1 to 41-n) among the plurality of radar waveguides (41, 41-1 to 41-n) are covered on the outer side of the window (50) by at least one anti-reflection layer, the layer thickness of which is an integer multiple of a quarter of the radar wavelength provided for wave guiding in the anti-reflection layer.

8. A method of manufacturing a window (10) for radar environment detection according to any one of claims 1 to 7, the method comprising the following steps: Manufacturing or providing a window (50) having an inner side and an outer side, wherein a plurality of radar waveguides (41, 41-1 to 41-n) are configured in the window (50) for guiding radar radiation from the inner side to the outer side and / or vice versa for guiding radar radiation from the outer side to the inner side, wherein the radar waveguides (41, 41-1 to 41-n) guide the waves of the radar radiation (100) by means of a refractive index change.

9. The method according to claim 8, characterized in that Refractive index modulation is designed in the material (59) of the window (50) by means of a non-linear multi-photon process in such a way that the focus of the focused laser moves in the volume of the material of the window (50).

10. The method according to claim 8 or 9, characterized in that Calibration waveguides are configured between the reflective waveguides.

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