Illumination device, front-end structure and vision system for a motor vehicle

Abstract

The invention relates to an illumination device (10) for motor vehicle (22), wherein the illumination device (10) comprises at least one infrared light source (11) which is adapted to emit light in the infrared range. The illumination device (10) is configured to emit a multitude of infrared light beams or infrared light cones (13) generated by the at least one infrared light source (11) from a multitude of infrared light emitting positions (12) dispersed over an area, wherein said infrared light emitting positions (12) are spaced at least 1 cm apart from each other.

Description

[0001] Illumination device, front-end structure and vision system for a motor vehicle

[0002] The invention relates to an illumination device for motor vehicle, wherein the illumination device comprises at least one infrared light source which is adapted to emit light in the infrared range. Further, the invention relates to a front-end structure for a motor vehicle and vision system for a motor vehicle. Moreover, the invention relates to a method to control a corresponding vision system.

[0003] Modern motor vehicles often comprise advanced driver assistance systems (ADAS) or automated driving systems (ADS) . The capabilities of such systems rely among other things on the detection of objects in front of the motor vehicle. Higher speeds of the motor vehicles, e.g. 130 km / h, require detection ranges of 150 m, wherein the ADAS or ADS must be able to detect small objects on the road which cannot be driven over. Such requirements are UN ECE R157, for example.

[0004] Existing detection systems, like LIDAR, struggle to achieve the required spatial resolution and are expansive. Camera based vision systems may achieve sufficient depth information and spatial resolution at a low cost. Nonetheless, the effective range of ADAS or ADS cameras is limited in darkness and low visibility conditions.

[0005] Improving the visibility by illumination the forward area of the vehicle to the required ranges is constrained in the wavelengths visible to humans by glare effects on oncoming traffic as well as by eye safety constraints in the inf rared wavelengths regarding people in f ront of the vehicle .

[0006] US 2021 / 400177 Al discloses a system for lighting a lateral region of a vehicle , comprising two luminous modules each emitting a corresponding light beam, wherein the two light beams are oriented toward each other .

[0007] It is the obj ect of the invention to provide an illumination device for a motor vehicle , a f ront -end structure for a motor vehicle with an illumination device , and vision system for motor vehicle that enables improved detection ranges in low vis ibility conditions beyond low-beam range which is limited by regulation to prevent glare to other road users . It is further the obj ect of the invention to provide a corresponding controlling method .

[0008] The invention solves this obj ect with the features of the independent claims .

[0009] An illumination device for motor vehicle is proposed, wherein the illumination device comprises at least one inf rared light source which is adapted to emit light in the inf rared range . More particularly, an inf rared light source is a light source which has a peak emittance in the IR wavelength range . It is proposed that the illumination device is conf igured to emit a multitude of inf rared light beams or inf rared light cones generated by the at least one inf rared light source f rom a multi tude of inf rared light emitting positions , wherein said inf rared light emitting positions are spaced at least 1 cm apart from each other . The illumination in the infrared range is outside the visible spectrum so that glare limitations do not have to be considered. Thus, light patterns comparable to high beam illumination can be used for an increased effective detection range of a camera of an ADAS / ADS system operating in the infrared spectrum (i.e. , having a peak sensitivity in the IR wavelength range) in a dark environment. Further on, the spaced multitude of infrared emitting positions enable the illumination device to comply with any eye safety regulation, like IEC 60825-1 for class 1 laser or IEC 62471 for other light sources like LEDs while at the same time the combined illumination levels in front of a motor vehicle in a distance up to 150 m can be significantly improved. The illumination device has preferably at least four, more preferably at least ten infrared light emitting positions. This allows a good illumination level and thus a good detection range of an ADAS / ADS camera. The infrared light emitting positions can preferably be arranged in an array or matrix arrangement .

[0010] Due to the distance of the infrared light emitting positions from each other, the infrared light beams or infrared light cones do not superimpose in close proximity to their respective infrared ight emitting positions, thus superimposing or merging of the multitude of infrared light beams or infrared light cones is at certain distance in front of a vehicle. In general, the power per area is proportional to the inverted squared distance, so that power per area or the intensity of infrared light emitted from any of the infrared light emitting positions is reduced by the square of the distance. Thereby, the merging of the multitude of infrared light beams or infrared light cones occurs only in a distance where the intensity of the infrared light beam or infrared light cone is reduced due to geometric reasons. Each infrared light beam is preferably at a level below the eye safety limit, and the distance where the merging of the multitude of light beams occurs is such that their combined intensity is also below the eye safety limit.

[0011] With the proposed illumination device, it is possible to comply with the eye safety limits and the maximum permissible exposure at any position in front of the illumination device, while it is also possible to illuminate objects in the field of view at distances greater than 100 m, e.g. 150 m, wherein light from multiple infrared light emitting points can reach such an object, so that a sufficient illumination with infrared light of objects is possible. As a result, the detection range of an ADAS / ADS can be increased.

[0012] Preferably, the infrared light beams or infrared light cones are directed into the far field to illuminate an object more than 10 m, preferably more than 50 m, further preferably more than 100 m, away. Accordingly, the multitude of infrared light beams or infrared light cones are preferably aligned nearly parallel or parallel. As a result, it is not possible to hit an eye pupil of a person with infrared light beams or infrared light cones in a position at the eye safety determined distance of 10 cm such that the combination exceeds the eye safety limit in any infrared light emitting position.

[0013] Light beams are generally divergent, even laser light beams. Furthermore, light cones are divergent, thus the intensity is reduced with increased distance travelled. An infrared light source is preferably an LED or laser diode.

[0014] In a preferred embodiment, the multitude of infrared light emitting positions are spaced at least 10 cm apart from each other with respect to a horizontal axis. Thereby, the position where light from infrared light emitting positions is superimposed can be at a greater distance from the respective infrared light emitting positions. Thus, the respective infrared light beams or infrared light cones have a superimposing distance that is even further away from the infrared light emitting position. It is further preferred that the at least three, preferably at least four, infrared light emitting positions are spaced at least 10 cm apart from each other with respect to a vertical axis.

[0015] In a preferred embodiment, the opening angle of the infrared light beams or infrared light cones is approximately 30° in the horizontal direction and approximately 20° in the vertical direction, in line with preferred laser diodes fast and slow axis divergence angles. This is advantageous to illuminate an area in a far field and to superimposed the infrared light beams or infrared light cones emitted from infrared light emitting positions at a greater distance from the illumination device .

[0016] Preferably, at least two of the multitude of infrared light emitting positions are at a distance of at least 50 cm from each other with respect to a horizontal axis. Also preferably, the infrared light emitting positions are covering an area spaced at least 40 cm apart from each end with respect to a horizontal axis. The illumination device can be spread over a wider area, so that the merging of infrared light beams or infrared light cones can be even further away from the illumination device.

[0017] Preferably, the multitude of infrared light beams or infrared light cones superimpose at a distance larger than 100 mm, preferably larger than 200 mm, from the respective light emitting positions. Thereby, the intensity of the superimposed infrared light beams or infrared light cones can be kept within the safety limits, also considering various manufacturing tolerances .

[0018] In advantageous embodiments, the infrared light emitting positions form a distributed light source. An infrared light emitting position is preferably an optical window and / or a lens, in particular an optical window and / or a lens with a diameter smaller than 5 mm. The infrared light emitting positions can be sourced from a single infrared light source or from multiple infrared light sources, wherein infrared light from the infrared light source or sources can be guided by means of light guides, light pipes, and / or light bars. It is further possible to have apertures or emitting zones wherein prisms, micro-lens arrays, laser etching of fibers, and / or perturbations on the fiber surface are used.

[0019] In a preferred embodiment, each infrared light emitting position is fed by one or more respective infrared light sources. Thus, each light emitting position can be sourced or operated by one or more dedicated light sources, which can feed just one infrared light emitting position in an advantageous embodiment .

[0020] Preferably, each infrared light source consists of a multitude of infrared light emitters. „Multitude" in the context of this application generally means at least three or four, preferably at least ten or 16, even more preferably at least 50 or 100. A practical embodiment comprises 128 laser diodes each consisting of a bar having 4x1 laser emitting points. Preferably, each infrared light source consists of an array or matrix of infrared light emitters; i.e. , the infrared light emitters of the or each infrared light source are preferably arranged in a matrix or an array.

[0021] Advantageously, each infrared light emitting position is in accordance with IEC 60825-1 class 1 or IEC 62741. It is further preferred that each infrared light source of the illumination device is in accordance with class 1 of IEC 60825-1 or IEC 62741.

[0022] It is further preferred that each infrared light source is pulsed in synchronization with a shutter of a gated infrared camera. This enables the infrared illumination device to be used with gated infrared cameras in an ADAS or ADS, so that the negative impact of fog or other adverse weather conditions due to back- scattering in the field of view can be mitigated. An infrared camera is a camera having a peak sensitivity in the IR wavelength range. The gated infrared camera also serves to limit interference from the infrared illumination device of similar systems on other vehicles travelling towards the subject vehicle.

[0023] In a further advantageous embodiment, each infrared light source (11) or the infrared light sources (11) have a combined peak pulsed optical power output of maximum 1800 W when operated at 20 ns pulse duration and a pulse repetition rate of 10 kHz, equivalent to an average optical power output at 0,36 W. In a practical embodiment, each eye-safe cluster consists of 3x2 laser diodes, where each laser diode consists of a bar with 4x1 laser output points, thus having a combined output of 38.4 kW. Accordingly, a distant object that is 150 m away, for example, can be sufficiently illuminated by the proposed illumination device so that even small objects of 10 cm high can be detected by means of an ADAS / ADS camera.

[0024] Preferably, the infrared light emitting positions are arranged asymmetrical with respect to a horizontal axis and / or a vertical axis, in particular of a front-end structure.

[0025] Further preferably, the infrared light emitting positions are arranged in a different shape than the shape of an area illuminated by the illumination device. This is a useful design parameter considering, for example, that a laser diode as infrared light source has different beam shapes in the fast axis and the slow axis directions.

[0026] In order to solve the object of the invention, a front -end structure for a motor vehicle is proposed which comprises an illumination device as described above or according to claims 1 to 10.

[0027] The front-end structure comprises preferably a molded plastic part in which the illumination device is fastened. In preferred embodiments, optical openings or optical aperture are molded in the front structure by using optical film, for example. The front-end structure is preferably processed by film inserted injection molding. The optical film is preferably scratch resistant.

[0028] Further, the one or more infrared light sources of the illumination device are preferably molded, preferably insert molded, into the front-end structure for a motor vehicle.

[0029] Preferably, the front-end structure is a grille. The grille for a motor vehicle offers an area where the infrared light emitting positions or infrared light sources can be further distributed so more than 4, preferably more than 8, further preferably more than 16, even more preferably more than 50 or 100 infrared light emitting positions or infrared light sources of an illumination device can be integrated in the grille. In advantageous embodiments, the front -end structure for a motor vehicle can have the same color as the body color of the motor vehicle to be mounted on, and further preferably lighting in the visible range may create a signature lighting sign appearing on the front -end structure. The surface of the front -end structure is preferably water repellant by a hydro- phobic and super hydrophobic treatment, for example.

[0030] In preferred embodiments, the grille has at least a width of 60 cm in a horizontal axis. Preferably, at least six, preferably more than 8, further preferably more than 16, even more preferably more than 50 or 100 infrared light emitting positions or infrared light sources of the illumination device can be arranged spaced apart from each other along a horizonal axis .

[0031] It is further preferred that the front-end structure comprises an infrared camera. This is beneficial for the alignment of the infrared camera with respect to the infrared light emitting positions and the respective infrared light beams or infrared light cones. Additionally, the illumination device and the infrared camera can be calibrated as a unit that can be fastened to a motor vehicle without the need for further calibration. The front-end structure or the grille can integrate a high level of functionality in a compact space.

[0032] In advantageous embodiments, the front -end structure has a heating element to keep the infrared light emitting positions and / or other sensor elements or the infrared camera ice and moisture free.

[0033] Preferably, the illumination device is adapted to illuminate the field of view of the infrared camera with at least three four, preferably more than 8, further preferably more than 16, even more preferably more than 50 or 100 infrared light beams or infrared light cones from a corresponding number of light emitting positions, respectively.

[0034] Further, a vision system for a motor vehicle is proposed, wherein the vision system comprises an illumination device as described above or according to any one of the claims 1 to 10. The vision system comprises an infrared camera with a field of view that is preferably in the range between 33x23 degree to 27x17 degree, more preferably 30x20 degree, wherein the illumination device is adapted to illuminate the field of view of the infrared camera with a multitude of at least three or four, preferably more than 8, further preferably more than 16, even more preferably more than 50 or 100 infrared light beams or infrared light cones from respective multitude of at least three or four light emitting positions. The infrared camera can be arranged in a front -end structure of a motor vehicle, in particular in a grille, or behind a windshield of the motor vehicle .

[0035] In a preferred embodiment, the at least one infrared light source of the illumination device is adapted to be operated in a pulsed mode and the infrared camera is configured for gated imaging. Thereby, detecting small object of about 10 cm height is possible at 150 m distance even in dark and / or foggy or snowy conditions. Further a method for controlling a vision system as described above or according to claim 16 is proposed, wherein each infrared light source is operated in a pulsed mode and the infrared camera is taking gated images of a scene illuminated by the light source or the light sources for a time-of - f light range between 20 m and 200 m, preferably between 50 m and 150 m. The inf rared light sources are preferably synchronized with an electronic shutter function in the inf rared camera . With gated imaging, it is possible to capture an inf rared image of the scene in f ront of the inf rared camera that is limited to the distance of the scene time-of - f light distance of the camera ' s gate timing .

[0036] This allows to reduce any unwanted ref lections or back- scatter from the inf rared light emitted by the illumination device at distances outside the range corresponding to the open gate timing . The gated imaging system also reduces disturbances generated by light f rom other sources in the environment in a captured inf rared image .

[0037] In the following the invention shall be illustrated on the basis of preferred embodiments with reference to the accompanying drawings . Therein shows :

[0038] Fig . 1 a schematic f ront view of an illumination device with multiple inf rared light emitting positions and a common inf rared light source ;

[0039] Fig . 2 a schematic f ront view of an illumination device with multiple inf rared light sources ; Fig. 3 a top view of an illumination device with four infrared light cones superimposed at a superimposing distance;

[0040] Fig. 4 a schematic front view of a front-end structure for a motor vehicle with an illumination system;

[0041] Fig. 5 a schematic view of a vision system with of an illumination system and an infrared camera in a grille for a motor vehicle;

[0042] Fig. 6 a schematic view of a vision system with of an illumination system and an infrared camera; and

[0043] Fig. 7 a schematic top view of a motor vehicle on a road with an illumination system.

[0044] In Figure 1 an embodiment of an illumination device 10 for a motor vehicle 22 is schematically shown in a front view. The illumination device 10 comprises one infrared light source 11 which is adapted to emit light in the infrared range. The infrared light from the infrared light source 11 is divided and transferred to a multitude of infrared light emitting positions 12, in this embodiment sixteen infrared light emitting positions 12. Other embodiments may have a different number of infrared light emitting positions 12, for example, four, eight, twelve or more, e.g. more than 16, more preferably more than 50 or 100 infrared. The infrared light emitting positions 12 of the illumination device 10 are spaced at least 1 cm apart from each other. Thus, the distance between any two light infrared emitting positions 12 is at least 1 cm. In this advantageous embodiment the infrared light emitting positions 12 are spaced 10 cm apart from each other with respect to a horizontal axis 16. Furthermore, the infrared light emitting positions 12 are spaced 10 cm apart from each other with respect to a vertical axis 15.

[0045] The infrared light emitting positions 12 are arranged in two rows or arrays with eight infrared light emitting positions 12 in each row or array. In alternative embodiments, other arrangements of the infrared light emitting positions 12 are possible, for example, grid or matrix arrangement, staggered arrangement, equilateral triangle arrangement, or circumferential arrangement . There is no upper limit to the number of infrared light emitting positions 12 in an arrangement of infrared light emitting positions 12 and the number can be set as appropriate for technical aspects, like overall infrared light power output without concerns regarding eye safety. A grid or matrix arrangement can be 8x2, 6x4, or 8x16 for example.

[0046] In this embodiment, eight infrared light emitting positions 12 are aligned parallel to a horizontal axis 16. The most right infrared light emitting position 12 and the most left infrared light emitting position 12 are 70 cm away in this embodiment, so that the infrared light emitting positions 12 of the illumination device 10 are spread 70 cm in width and 10 cm in height .

[0047] Figure 2 shows another embodiment of an illumination device 10 for motor in a front view. In this embodiment each light emitting position 12 is fed by an individual infrared light source 11. The infrared light source 11 can be a laser diode or an LED. The infrared light emitting positions 12 and the infrared light sources 11 are spaced apart in the same way as in Figure 1. Figure 3 shows such an illumination device 10 in a top view, wherein the infrared light beams or infrared light cones 13 generated by the one or more infrared light sources 11 emerge from the infrared light emitting positions 12. An infrared light emitting positions 12 is preferably an optical window transparent in the IR wavelength range. Due to the spacing between the infrared light emitting positions 12 and the opening angle of the infrared light cones 13 which is smaller than 30°, the infrared light cones 13 superimpose at a superimpose distance 14 of at least 100 mm or 200 mm. A longer superimpose distance 14 can be better, so that the intensity of the infrared light beams or infrared light cones 13 is lower due to divergence before infrared light beams or infrared light cones 13 are superimposed in order to achieve high illumination levels in the far field in front of a motor vehicle 22. Thereby, requirements of IEC 60825-1 and IEC 62741 can be fulfilled while the illumination level in the far field, e.g. 150 m, can be increased to detect objects of 10 cm height with an infrared camera 31, see Figures 5 and 6.

[0048] Figure 4 shows an embodiment of a front -end structure 20 for a motor vehicle 22 with an illumination device 10 according one of the embodiments described above. The front -end structure 20 is preferably a grille 21 for a motor vehicle 22, in particular, a battery electric vehicle (BEV) . In BEVs less cooling is needed so that the multiple functions can be easily integrated in the grille 21. The front-end structure 20 or the grille 21 offers a sufficient front area to spread the infrared light emitting positions 12 sufficiently to remain eye-safe per IEC 60825-1 for class 1 laser. Spreading the light emitting positions 12 is in particular possible along a horizontal axis 16 in a grille 21, for example in an 8x2 arrangement of the infrared light emitting positions 12. The grille 21 has a width of 100 cm in this embodiment.

[0049] The front -end structure 20 with an illumination device 10 of Figure 4 is shown in Figure 5, wherein the front -end structure 20 comprises an infrared camera 31. The infrared camera 31 in this preferred embodiment has a narrow field of view of 30x20 degree, a resolution of 6M pixel and a frame rate of 20 Hz.

[0050] The area illuminated by the illumination device 10, where multiple infrared light beams or infrared light cones 13 are superimposed, is preferably the sensing area of the infrared camera 31.

[0051] The illumination device 10 and the infrared camera 31 as shown in Figure 5 form a vision system 30.

[0052] Figure 6 shows another embodiment of a vision system 30, wherein the infrared camera 31 is not arranged in the frontend structure 20 or grille 21 for a motor vehicle 22. In this embodiment, the infrared camera 31 can be arranged behind a windshield of a motor vehicle 22.

[0053] The vision systems 30 of embodiments according to Figures 5 and 6 are advantageously configured to perform gated imaging, wherein the illumination device 10 is operated in a pulsed mode, so that the vision system 30 is adapted to capture gated images with a time-of -flight corresponding to a distance of 50 m to 150 m.

[0054] Figure 7 shows a motor vehicle 22 with an illumination device 10 that is arranged in a front -end structure 20 of the motor vehicle 22. The illuminated area is illustrated, whereby in this example three infrared light cones 13 are emitted from three spaced infrared light emitting positions 12 at the front-end structure 20. The infrared light cones 13 do not overlap or superimpose in zone A. Zone B starts at a superimpose distance 14 from the infrared light emitting positions 12, where the infrared light beams or infrared light cones 13 overlap and thus superimpose. In zone A as well as in zone B eye safety standards can be met while a good illumination with light in the infrared range can be achieved.

Claims

Claims :

1. Illumination device (10) for motor vehicle (22) , wherein the illumination device (10) comprises at least one infrared light source (11) which is adapted to emit light in the infrared range, characterized in that the illumination device (10) is configured to emit a multitude of infrared light beams or infrared light cones (13) generated by the at least one infrared light source (11) from a multitude of infrared light emitting positions (12) dispersed over an area, wherein said infrared light emitting positions (12) are spaced at least 1 cm apart from each other.

2. Illumination device (10) according to claim 1, characterized in that the infrared light emitting positions (12) are covering an area spaced at least 40 cm apart from each end with respect to a horizontal axis (16) .

3. Illumination device (10) according to claim 1 or 2 , characterized in that the opening angle of the infrared light beams or infrared light cones (13) is smaller than 30°.

4. Illumination device (10) according to any one of the preceding claims, characterized in that the multitude of infrared light beams or infrared light cones (13) superimpose at a superimpose distance (14) larger than 100 mm from the respective infrared light emitting positions (12) .

5. Illumination device (10) according to any one of the preceding claims, characterized in that each infrared light source (11) consists of an array or matrix of infraredlight emitters.

6. Illumination device (10) according to any one of the preceding claims, characterized in that each infrared light emitting position (12) is in accordance with IEC 60825-1 class 1 or IEC 62741.

7. Illumination device (10) according to any one of the preceding claims, characterized in that each infrared light source (11) is pulsed in synchronization with a shutter of a gated infrared camera (31) .

8. Illumination device (10) according to any one of the preceding claims, characterized in that each infrared light source (11) or the infrared light sources (11) have a combined peak pulsed optical power output of maximum 1800 W when operated at 20 ns pulse duration and a pulse repetition rate of 10 kHz, equivalent to an average optical power output at 0,36 W.

9. Illumination device (10) according to any one of the preceding claims, characterized in that the infrared light emitting positions (12) are arranged asymmetrical with respect to a horizontal axis (16) and / or a vertical axis (15) .

10. Illumination device (10) according to any one of the preceding claims, characterized in that the infrared light emitting positions (12) are arranged in a different shape than the shape of the area illuminated by the illumination device (10) .

11. Front-end structure (20) for a motor vehicle (22) , characterized in that the front-end structure (20) comprises an illumination device (10) according to any one of the preceding claims.

12. Front-end structure (20) according to claim 11, characterized in that the front-end structure (20) is a grille(21) .

13. Front-end structure (20) according to claim 12, characterized in that the grille has at least a width of 60 cm in a horizontal axis (16) .

14. Front-end structure (20) according to any one of claims 11 to 13, characterized in that the front-end structure (20) comprises an infrared camera (31) .

15. Vision system (30) for a motor vehicle (22) , characterized in that the vision system (30) comprises an illumination device (10) according to any one of the claims 1 to 10, wherein the vision system (30) comprises an infrared camera (31) with a field of view that preferably is in the range between 33x23 degree to 27x17 degree, more preferably 30x20 degree, wherein the illumination device (10) is adapted to illuminate the field of view of the infrared camera (31) with a multitude of infrared light beams or infrared light cones (13) from a multitude of infrared light emitting positions (12) .

16. Vision system (30) according to claim 15, characterized in that the or each infrared light source (11) of the illumination device (10) is adapted to be operated in a pulsed mode and the infrared camera (31) is configuredfor gated imaging.

17. Method for controlling a vision system (30) according to claim 16, characterized in that each infrared light source (12) is operated in a pulsed mode and the infrared camera (31) is taking gated images of a scene illuminated by the light source or the light sources (12) for a time- of-flight range between 20 m and 200 m, preferably between 50 m and 150 m.

Images