Lighting device comprising radar-transparent section and heating element
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- MAGNA EXTERIORS GMBH
- Filing Date
- 2024-08-12
- Publication Date
- 2026-07-01
Smart Images
Figure EP2024072690_27022025_PF_FP_ABST
Abstract
Description
[0001] Description
[0002] title
[0003] Lighting device with radar-transparent section and heating element
[0004] State of the art
[0005] The invention relates to a lighting device with a radar-transparent section and a heating element.
[0006] Disclosure of the invention
[0007] When designing a motor vehicle, the degree of design freedom is often limited by the available or specified installation space. This is particularly true when it comes to accommodating driver assistance systems such as radar. The radar can be located, for example, behind a front grille of the vehicle, particularly behind a logo, in order to detect the vehicle's path. If an aesthetic factor, such as illuminating the logo in the front grille, also needs to be considered, the degree of design freedom is further reduced.
[0008] To ensure the best possible radar transparency of the lighting system, the lighting system should have a height, in the direction of action of the radar system, of a length that is a multiple of λ / 2 the wavelength of the radar radiation in the corresponding medium, or a multiple of this length. Furthermore, the area of the lighting system through which the radar radiation passes must not be iced up, which is why the heating element is provided on the lighting system.
[0009] Typically, the heating element is positioned in such a way that it is not visible from the outside. However, this often negatively impacts the coupling of light into the lighting system, since the height of the lighting system is essentially determined by the wavelength of the radar radiation.
[0010] What is desirable is a lighting device, in particular for illuminating a logo in a front grille, which comprises the heating element and is transparent to radar radiation, whereby the light coupling into the lighting device is improved without the heating element being visible from the outside.
[0011] This object is achieved by a lighting device according to an independent claim.
[0012] One aspect of the description relates to the following subject matter: A lighting device, in particular for a motor vehicle, comprising at least one light source for emitting light; a light-guiding section which, with respect to an optical axis of the lighting device, is arranged, for example radially, outside a radar coupling surface for coupling in radar beams of a radar-transparent section and extends at least in sections along an imaginary circumferential path, wherein the light-guiding section comprises a light coupling surface for coupling in the light of the light sources, and wherein the light-guiding section guides the coupled-in light from the light coupling surface to a light transition region between the light-guiding section and the radar-transparent section;and the radar-transparent inner section with the radar coupling surface for coupling in the radar radiation and with a coupling-out surface for coupling out the coupled radar radiation and for emitting a light distribution depending on light introduced into the inner radar-transparent section by means of the light-guiding section, wherein the radar-transparent section comprises at least one, in particular a plurality of heating elements;
[0013] The heating elements prevent, for example, the lighting system, particularly the coupling surface, from icing up. This ensures safe operation, for example, of a radar system that couples radar radiation into the radar-transparent area. Furthermore, the operation of driver assistance systems, which in particular have a radar-based functionality, is improved in terms of safety and failure probability. In general, this enables safe operation of the motor vehicle.
[0014] An advantageous example is characterized in that the at least one heating element leads at least partially through a light-guiding region of the radar-transparent section.
[0015] By incorporating the heating element into the radar-transparent section, the distance of the light transition region in the direction of the optical axis is increased, while maintaining a height of the radar-transparent region in the direction of the optical axis 4 of approximately a multiple of λ / 2 of the radar radiation. The increased distance improves light coupling into the radar-transparent section without impairing the operation of the radar device.
[0016] An advantageous example is characterized in that a surface of the heating element comprises the color white or a shade of white, in particular in the form of a layer applied to the heating element.
[0017] The applied layer increases the heating element's scattering effect on incident light. This reduces any visible shadows from the heating element or hot spots from the heating wire in the emitted light distribution.
[0018] An advantageous example is characterized in that the radar-transparent section comprises light-transparent openings in a transmission-inhibiting layer with reduced light transmittance.
[0019] The transparent openings allow you to freely choose the appearance of the emitted light distribution. For example, a pattern or brand can be displayed.
[0020] An advantageous example is characterized in that a reflection section of the radar-transparent section, oriented toward the coupling surface for coupling the radar radiation, comprises at least sections of reflection surfaces with increased scattering effect for incident light. Due to the reflection surfaces with increased scattering effect, the light coupled into the radar-transparent section or light-guiding section is stochastically scattered upon impact with the reflection surfaces. The light therefore loses its preferred direction and radiates in all directions with comparable intensity, thus shining more frequently in the direction of the radar output surface, thereby improving the brightness and intensity of the emitted light distribution.
[0021] An advantageous example is characterized in that the reflection surfaces with increased scattering effect are arranged in such a way that the reflected and scattered light passes through the respectively assigned light-transparent opening.
[0022] This orientation of the reflection surfaces with increased scattering effect improves the appearance of the emitted light distribution as shown through the light-transparent openings in terms of brightness and light intensity.
[0023] An advantageous example is characterized in that a partially transparent layer, which in optical appearance appears, for example, chrome-like, with a higher transmittance than the transmission-inhibiting layer, closes the openings at least in sections.
[0024] Thanks to the chrome-like layer, the pattern projected through the openings appears with a chrome-like shine even when the light source is turned off. This makes the pattern more easily recognizable even when the light source is turned off.
[0025] An advantageous example is characterized in that the at least one heating element is arranged between the associated light-transparent opening and the reflection section, in particular one of the reflection surfaces with increased scattering effect.
[0026] This arrangement of the heating element means that part of it is covered by the transmission-inhibiting layer. This makes the heating element less visible in a top view of the lighting device. An advantageous example is characterized by the fact that the light-guiding area is manufactured separately, at least in sections, in particular as a heating segment.
[0027] By manufacturing the light guide area separately, the lighting device as a whole is easier to manufacture because geometric complexity is reduced.
[0028] An advantageous example is characterized in that a carrier comprises the at least one heating element, wherein the carrier, as part of the radar-transparent section, provides the radar coupling surface for coupling in the radar radiation.
[0029] This simplifies the production of the lighting device because the heating element can be easily and separately embedded into the carrier.
[0030] An advantageous example is characterized in that the carrier is connected to a reflection section of the radar-transparent section.
[0031] Assembly and production of the entire lighting system are simplified because the support and the radar-transparent section can be manufactured individually from simple geometric shapes. Furthermore, the heating element no longer runs in the light guide area of the radar-transparent section, allowing the coupled light to be guided unhindered within the radar-transparent section. Accordingly, the heating element is no longer visible in the top view of the lighting system.
[0032] An advantageous example is characterized by the fact that the carrier is opaque.
[0033] Further advantageous embodiments are apparent from the drawing and the following description. The drawing shows:
[0034] Figure 1: a schematic representation of a section of a lighting device;
[0035] Figure 2: a schematic representation of the section of an embodiment of the lighting device; Figure 3: a schematic representation of the section of an embodiment of the
[0036] lighting equipment; and
[0037] Figure 4: a schematic representation of a top view of the lighting device;
[0038] Figure 1 shows a lighting device 2, in particular for a motor vehicle, in a schematic representation in a section AA. The lighting device 2 comprises at least one light source 100, 100a, 100b for emitting light and a light-guiding section 200, which, with respect to an optical axis 4 of the lighting device 2, is arranged, for example, radially outside a radar coupling surface 402 for coupling in radar beams 6 of a radar-transparent section 400 and extends at least in sections along an imaginary circumferential section 220. The imaginary circumferential section 220 can, for example, be circular, polygonal, or designed as any desired line. The circumferential section 220 can be closed in itself or open in sections. In the example, the circumferential section 220 is essentially circular and closed in itself.It can be provided that the circumferential section 220 is adapted to a predetermined installation space for the lighting device 2. As a result, the light guide section 200 can also be adapted or adapted to the installation space.
[0039] In the example, the light source 100, 100a, 100b is embodied as an LED. It can be provided that a plurality of LEDs are arranged on a circuit board and form the light source 100, 100a, 100b. Furthermore, it can be provided that an LED strip forms the light source 100, 100a, 100b. LEDs with one or more selected colors or RGB LEDs can be used, whereby the individual light sources of the RGB LEDs can generate the colors directly or at least some of the colors are generated using blue or UV-pumped color converters / fluorescent dyes.
[0040] For example, the light source 100, 100a, 100b is formed from a circuit board 108 with LEDs arranged thereon. The circuit board 108 can be designed as a continuous or split circuit board. The LEDs arranged on the continuous and / or split circuit board 108 can be arranged in groups of varying numbers and with varying or uniform spacing between the LEDs or the groups.
[0041] In the example, the LEDs of the light source 100, 100a, 100b are arranged in a plane 110. It may be provided that the LEDs are arranged in different planes.
[0042] The light guide section 200 comprises at least one light coupling surface 202 for coupling in the light of the light sources 100, 100a, 100b, wherein the light guide section 200 guides the coupled light 102 from the light coupling surface 202 to a light transition region 300 between the light guide section 200 and the radar-transparent section 400.
[0043] In addition, the light-guiding section (200) has a light-guiding surface (208) towards the light transition region (300) formed by a convex outer contour (206) facing away from an imaginary extension of the optical axis (4) of the lighting device (2).
[0044] The curvature of the convex outer contour 206 can be adapted to the specified installation space for the lighting device 2. Furthermore, the curvature of the convex outer contour 206 can be provided with different degrees of curvature at corresponding points on the imaginary circumferential section 220. In a preferred embodiment, the light-guiding surface 208 is created by rotating the convex outer contour 206 around the optical axis 4.
[0045] The convex outer contour 206 can be designed in its basic form as an ellipse, which can be deformed into a free-form surface due to given conditions or a desired guidance of the light 102.
[0046] The lighting device 2 further comprises the radar-transparent inner section 400 with the radar coupling surface 402 for coupling in the radar radiation 6 and with a coupling-out surface 404 for coupling out the coupled radar radiation 6 and for emitting a light distribution 106 depending on light 104 introduced into the inner radar-transparent section 400 by means of the light-guiding section 200. The radar-transparent section 400 is designed to couple incoming radar radiation into the radar-transparent section 400 at the coupling-out surface 404 and to couple it out at the radar coupling surface 402.
[0047] In the example, the radar radiation 6 is generated and processed by a radar device 8.
[0048] The radar-transparent section 400 comprises at least one, in particular a plurality of heating elements 10.
[0049] The heating element 10 is depicted in the example as a plurality of heating coils. In the example, the heating coils consist of an electrically conductive material, in particular a metal wire, for example a copper wire and / or nickel wire.
[0050] In this example, the radar-transparent section 400 and the light-guiding section 200 are made of a material transparent to visible light, such as PC, PU, PUR PMMA, or silicone. Different materials can also be used for the respective sections.
[0051] It can be provided that the at least one heating element 10 leads at least partially through a light guide region 406 of the radar-transparent section 400.
[0052] The heating element 10 is thus integrated into the radar-transparent section 400 and is surrounded by material transparent to visible light. The overall height of the illumination device along the optical axis 4 remains correspondingly in a range of approximately a multiple of λ / 2 of the radar radiation 6, and at the same time, a distance 302 of the light transition region 300 is increased. In one example, the radar radiation has a frequency of 76.5 GHz, whereby the overall height of the illumination device 2 is 1.4 mm when polycarbonate is used as the radar-transparent section 400. At multiples of this overall height, a transmission of the radar radiation 6 decreases with increasing order of the multiple. It can be provided that a surface 12 of the heating element 10 comprises the color white or a shade of white, in particular in the form of a layer applied to the heating element 10.
[0053] In the example, the heating element 10 has a wire diameter of 0.2 to 0.4 mm. The heating element 10 without the applied layer would be visible through the radar-transparent section 400 when the light source 100, 100a, 100b is switched off. When the light source 100, 100a, 100b is switched on, a shadow of the heating element 10 without the applied layer would be visible through the radar-transparent section. The applied layer causes the heating element 10 to be less visible when the light source 100, 100a, 100b is switched off. When the light source is switched on, the applied layer causes light incident on the surface 12 of the heating element 10 to be scattered in multiple directions, whereby the shadow of the heating element 10, in particular of the heating wire or parts of the heating wire, is less visible.
[0054] Figure 2 shows an embodiment of the illumination device 2 in section AA. The radar-transparent section 400 comprises light-transparent openings 408a, 408b in a transmission-inhibiting layer 408 with reduced light transmittance. In the example, the transmission-inhibiting layer 408 is provided as a lacquer layer. Films or other materials or intermediate layers are also conceivable. The transmission-inhibiting layer 408 can also be opaque.
[0055] By means of the light-transparent openings 408a, 408b in the transmission-inhibiting layer 408, any desired patterns or logos can be reproduced, through which the light 102 introduced into the radar-transparent section 400 exits. This results in illumination of the pattern formed by the light-transparent openings 408a, 408b, which is particularly visible in the plan view of the lighting device 2.
[0056] It can be provided that a reflection section 410 of the radar-transparent section 400, oriented in the direction of the coupling surface 202 for coupling the radar radiation 6, comprises at least in sections reflection surfaces 412a, 412b with an increased scattering effect for incident light. As a result, the light 102b introduced into the radar-transparent section 400 onto the reflection surfaces 412a, 412b is scattered, whereby more light rays are directed in the direction of the optical axis 4 and the light-transparent openings 408a, 408b. Thus, more light rays pass through the openings 408a, 408b. The reflection section region is a reflection region for visible light—not for radar radiation.
[0057] It can be provided that the reflection surfaces 412a, 412b with increased scattering effect are arranged such that the reflected and scattered light passes through the respective associated light-transparent opening 408a, 408b. In the example, the reflection surfaces 412a, 412b are aligned and arranged in alignment with the openings 408a, 408b.
[0058] It can be provided that a partially transparent layer 416, which has a chrome-like appearance, for example, and a higher transmittance than the transmission-inhibiting layer 408, closes the openings 408a, 408b at least in sections. In the example, the partially transparent layer 416 is formed continuously across the illumination device 2. The partially transparent layer 416 can be arranged before or after the transmission-inhibiting layer 408 in the optical direction. Alternatively, other appearances of the partially transparent layer 416 are conceivable, such as color filters. The partially transparent layer 416 can influence the appearance of the pattern imaged through the openings 408a, 408b even when the light source 100a, 100b is switched off.
[0059] It can be provided that the lighting device 2 is designed as part of a front grille for a motor vehicle or is integrated or can be integrated into it.
[0060] It can be provided that the at least one heating element 10 is arranged between the associated light-transparent opening 408a, 408b and the reflection section 410, in particular one of the reflection surfaces 412a, 412b with increased scattering effect.
[0061] It can be provided that the light-guiding region 406 is manufactured separately, at least in sections, in particular as a heating segment. The light-guiding region 406 can encompass the heating element 10. It can be provided that a carrier 414 encompasses the at least one heating element 10, wherein the carrier 414, as part of the radar-transparent section 400, provides the radar coupling surface 402 for coupling the radar radiation 6.
[0062] Figure 1 illustrates the carrier 414 by way of example. The ends of the carrier 414 can have a conical or perpendicular shape to the optical axis 4. These two shapes are shown as examples in Figure 1. It can be provided that the ends of the light-guiding region 406 have the same shape. Furthermore, other shapes for the ends of the carrier are conceivable, enabling a seamless assembly of the lighting device 2.
[0063] Figure 3 shows an embodiment of the lighting device in the section AA in a schematic representation.
[0064] It can be provided that the carrier 414 adjoins a reflection section 410 of the radar-transparent section 400. In this case, the carrier 414 and the heating element 10 are not arranged in the light-guiding region 406 of the radar-transparent section 400. The heating element 10 thus casts no visible shadows in the plan view of the lighting device 2.
[0065] The carrier 414 can be provided with an opaque finish. As a result, the heating element 10 is no longer visible in plan view, even when the light source 100, 100a, 100b is switched off. In this embodiment, the carrier 414 can be colored, for example, using color pigments to achieve the opaque property.
[0066] Figure 4 shows a schematic top view of the lighting device 2. Figure 4 shows the imaginary circumferential section 220 and an exemplary pattern depicted through the openings 408a, 408b. A schematic line path of section AA is also indicated.
Claims
Claims 1. A lighting device (2), in particular for a motor vehicle, comprising: at least one light source (100, 100a, 100b) for emitting light; a light-guiding section (200) which, with respect to an optical axis (4) of the lighting device (2), is arranged outside a radar coupling surface (402) for coupling in radar beams (6) of a radar-transparent section (400) and extends at least in sections along an imaginary circumferential path (204), wherein the light-guiding section (200) comprises a light coupling surface (202) for coupling in the light of the light sources (100), and wherein the light-guiding section (200) guides the coupled-in light (102) from the light coupling surface (202) to a light transition region (300) between the light-guiding section (200) and the radar-transparent section (400);and the radar-transparent inner section (400) with the radar coupling surface (402) for coupling in the radar radiation (6) and with a coupling-out surface (404) for coupling out the coupled radar radiation (6) and for emitting a light distribution (106) depending on light (104) introduced into the inner radar-transparent section (400) by means of the light-guiding section (200), wherein the radar-transparent section (400) comprises at least one, in particular a plurality of heating elements (10); 2. The lighting device (2) according to claim 1, wherein the at least one heating element (10) leads at least partially through a light-guiding region (406) of the radar-transparent section (400).
3. The lighting device (2) according to claim 2, wherein a surface (12) of the heating element (10) comprises the color white or a shade of white, in particular in the form of a layer applied to the heating element (10).
4. The lighting device (2) according to one of the preceding claims, wherein the radar-transparent section (400) comprises light-transparent openings (408a, 408b) in a transmission-inhibiting layer (408) with reduced light transmittance.
5. The lighting device (2) according to claim 4, wherein a reflection section (410) of the radar-transparent section (400) arranged oriented in the direction of the coupling surface (202) for coupling in the radar radiation (6) comprises at least in sections reflection surfaces (412a, 412b) with increased scattering effect for incident light.
6. The lighting device (2) according to claim 5, wherein the reflection surfaces (412a, 412b) with increased scattering effect are arranged such that the reflected and scattered light passes through the respectively associated light-transparent opening (408a, 408b).
7. The lighting device (2) according to one of claims 4 to 6, wherein a partially transparent layer (416) having an optical appearance, for example, of a chrome-like appearance and having a higher transmittance than the transmission-inhibiting layer (408) closes the openings (408a, 408b) at least in sections.
8. The lighting device (2) according to claim 2 or 3 and one of claims 4 to 7, wherein the at least one heating element (10) is arranged between the associated light-transparent opening (408a, 408b) and the reflection section (410), in particular one of the reflection surfaces (412a, 412b) with increased scattering effect.
9. The lighting device (2) according to one of the preceding claims, wherein the light-guiding region (406) is manufactured separately, at least in sections, in particular as a heating segment.
10. The lighting device (2) according to one of the preceding claims, wherein a carrier (414) comprises the at least one heating element (10), wherein the carrier (414) as part of the radar-transparent section (400) provides the radar coupling surface (402) for coupling in the radar radiation (6).
11. The lighting device (2) according to claim 10, wherein the carrier (414) adjoins a reflection section (410) of the radar-transparent section (400).
12. The lighting device (2) according to claim 10 or 11, wherein the carrier (414) is opaque.