Optical sensor system

Abstract

The present disclosure relates to an optical sensor system (10) comprising an optical reception device (12) configured to receive an optical signal (L) over an optical path from a monitoring area (32), wherein the optical sensor system (10) is configured to monitor the monitoring area (32) using the optical signal (L), wherein the optical sensor system (10) further comprises a housing (11) with a first cover (14) and a second cover (16) arranged in the optical path, wherein the second cover (16) comprises elastic material. The disclosure further relates to a use of the optical sensor system (10) in a vehicle (30), a system comprising the optical sensor system (10) and a vehicle (30).

Description

[0001] OPTICAL SENSOR SYSTEM

[0002] Field

[0003] The present disclosure relates to an optical sensor system and a use of the optical sensor system in a vehicle. The disclosure further relates to a system comprising the optical sensor system and a vehicle.

[0004] Background

[0005] Modern vehicles like cars, vans, trucks, motorcycles, etc. may comprise sensor systems, whose data are used for driver information and / or are used by driver assistance systems.

[0006] Sensor systems are constantly being developed for various functions, e. g. for the acquisition of environmental information in the near and far range of vehicles, such as passenger cars or commercial vehicles. Based on the acquired data, a model of the vehicle environment can be generated and a reaction to changes in this vehicle environment is possible. Sensor systems can also serve as sensors for driver assistance systems, in particular assistance systems for autonomous or semi-auton- omous vehicle control. They can for example be used to detect obstacles and / or other road users in the front, rear or blind spot areas of a vehicle.

[0007] An important optical sensor principle for environment detection, e. g. of vehicles, is the lidar technology (lidar: light detection and ranging). A lidar system comprises an optical transmission device and an optical reception device. The transmission device emits an optical signal, which can be continuous or pulsed. In addition, the optical signal may be modulated. For example, electromagnetic waves in the form of laser beams in the ultraviolet, visual or infrared range may be used as optical signals in a lidar system. The light is received by the optical reception device after reflection from an object in a monitoring area of the lidar system. The optical signal can for example be evaluated according to a time-of-flight method and the spatial position and distance of the object on which the reflection occurred can be determined. In addition, it may be possible to determine a relative velocity. Reflection or reflected light is understood to mean any light that is reflected back and should also include, in particular, light that is reflected back by scattering or absorption emission. Another example for an optical sensor system is the capture of images by a camera.

[0008] Summary

[0009] An optical sensor system comprises an optical reception device configured to receive an optical signal over an optical path from a monitoring area, wherein the optical sensor system is configured to monitor the monitoring area using the optical signal, wherein the optical sensor system further comprises a housing with a first cover and a second cover arranged in the optical path, wherein the second cover comprises elastic material.

[0010] The optical sensor system may comprise a camera. The optical reception device may comprise an image sensor of the camera. Optionally, the optical sensor system may also comprise an optical transmission device configured to transmit the optical signal. The optical sensor system may comprise a lidar system.

[0011] The second cover comprising the elastic material allows to compensate for tolerances between the first pane and any other surfaces and to adapt to different contours.

[0012] The housing may be designed to protect the components of the optical sensor system from environmental impact like e. g. dust, humidity, wind. The optical signal of the optical sensor system is transmitted and / or received via an aperture in the housing, which is covered by the first cover. The first cover may comprise material which lets optical signal pass, like e. g. plastics or glass. The first cover may comprise rigid material in order to enhance the mechanic stability of the housing and to properly protect the components of the optical sensor system.

[0013] The second cover is arranged in the optical path of the optical signal and preferably attached to the first cover facing outward of the housing. The elasticity of the second cover allows for the optical sensor system to be arranged in the vicinity of a third cover, which may comprise a hard surface, wherein a gap between the first cover and the third cover can be avoided. A possible gap between the first cover and the third cover can be filled with the elastic second cover. The elasticity of the second cover may allow to fill the gap. This avoids the transition of the optical signal via air in between the first and the third cover. This reduces attenuation in the optical path, because reflections and total reflections can be reduced. The second cover further allows to avoid the gap, which may prevent dirt, condensation, algae formation and similar to form between the first cover and the third cover. Avoiding the gap may avoid interference with the optical path and reflections between the first cover and the third cover. This may improve the optical detection quality. Ghosting and blooming may also be avoided.

[0014] In an embodiment of the optical sensor system the first cover and the second cover are transparent with respect to a range of optical frequencies, wherein the range of frequencies is around the frequency of the optical signal. The first and second cover are both arranged in the optical path. Additionally, they are designed specifically to let the optical signal pass. Other frequencies of electromagnetic radiation may be blocked or attenuated. For example, the first and / or second cover may be designed to block the ambient light from outside the housing. So, the housing with the first and second cover may shield the optical sensor system from ambient light.

[0015] In some embodiments, the second cover may be mixed with a material that renders it to be transparent for certain ranges of frequencies and opaque for others. The opaqueness and transparency for frequency ranges may be different from the first cover and / or different from the third cover. For example, the second cover may comprise a material that is transparent to infrared (IR) light while being opaque or less transparent to visible light. Such an embodiment is particularly useful for embodiments with the optical signal in the infrared range. The second cover may then additionally serve the purpose of an optical filter, a blinder and / or provide thermal insulation. At the same time, the first cover may be transparent to both - IR. and visible - frequency ranges.

[0016] Due to the elastic characteristic of the second cover, additional mechanical measures such as rubber seals or vacuum sealing may not be necessary, which helps to reduce cost.

[0017] In an embodiment of the optical sensor system the second cover is configured to be arranged in between the first cover and a third cover and to make an optical connection in between the first cover and the third cover. The third cover may be foreseen to e. g. further protect the optical sensor system or it may e. g. be foreseen for design reasons. The third cover may for example comprise another protective window in front of the second cover. In this embodiment the housing may comprise the first, the second and the third cover. The second cover with its elastic material allows to avoid a gap, e. g. filled with air, to form between the first and the third cover. This allows to realize the advantages as described above.

[0018] In an embodiment of the optical sensor system the second cover comprises adhesive material. The characteristic of the material comprised in the second cover provides for the ability of the second cover to let the optical signal path but also provides for an adhesive quality. This gives flexibility to the use of the optical sensor system and also how it may be mounted in its environment, e. g. a vehicle.

[0019] In an embodiment of the optical sensor system the second cover is configured to attach the optical sensor system to the third cover. For the embodiment of the second cover having adhesive characteristic, this allows for an easy attachment of the optical sensor system to the third cover without the need for additional fastening means. The third cover may also be arranged in the optical path of the optical sensor system and may also have the characteristic to let the optical signal path.

[0020] The elastic second cover may provide an additional shield of the optical sensor system from mechanical forces like vibrations.

[0021] The second cover may be configured to attach the optical sensor system to an interface structure of the third cover. The interface structure comprises a mechanical interface structure that establishes a physical connection between mechanical the optical sensor system and the third cover. It provides the geometry and dimension to connect the optical sensor system with the third cover. It may also be located in the optical path of the optical sensor system and therefore be optically transparent.

[0022] The interface structure may provide a suitable structure to make the mounting of the optical sensor system easy, e. g. by providing a surface where the optical sensor system may be mounted easily, e. g. by adhesion. It may also provide other methods of easy attachment, supporting e. g. the attachment with screws, bolts or the like. The interface structure may also provide a surface where the optical sensor system may be aligned easily and / or accurately to the proper position and that it is shielded from undesired mechanical forces like e. g. vibrations.

[0023] The third cover may comprise one of a windshield, a radiator grille, a bumper, a headlight, a window, or a pillar cover of the vehicle. The second cover being arranged in between the third cover and the first cover allows to avoid the gap in between the first and third cover. If the second cover provides has adhesive characteristics is allows an easy attachment of the optical sensor system to the third cover.

[0024] In an embodiment of the optical sensor system the second cover comprises silicone gel or silicone rubber. These materials allow to fill a potential gap between the first and third cover and at the same time may provide for a sufficient optical transmissibility. They may provide additional adhesive characteristics. The silicone rubber may be vulcanized during the manufacturing process or when mounting the optical sensor system. The silicone gel may for example be a Wacker Sil Gel 612.

[0025] In an embodiment of the optical sensor system the first cover, the second cover and / or the third cover comprises a heating device. For a use in a vehicle for example, this may provide for a proper clear view even in adverse temperature conditions. Possible heating devices that may be provided to free the optical sensor system from snow, ice or the like can be flexibly provided at the first, second and / or third cover, whichever is most suitable for the task. For embodiments in which the third cover comprises a windshield or window or headlight of the vehicle for example, the heating device already foreseen in the third cover may be used.

[0026] In an embodiment of the optical sensor system the optical refractive index of the second cover is in between the optical refractive index of the first cover and the optical refractive index of the third cover. The refractive index of the second cover may for example be roughly in the middle between the refractive index of the first cover and the refractive index of the third cover. Reflections and total reflections between the first and third cover can be reduced. This helps to reduce the attenuation introduced by the first, second and third cover in the optical path.

[0027] In an embodiment of the optical sensor system the refractive index of at least two of the covers is the same. When matching the refractive indices of two or three of the covers, the attenuation of the optical signal introduced by the combination of the first, second and third cover in the optical path may be reduced. Also, reflections and total reflections in between the first and the third cover may be reduced.

[0028] The described optical sensor system may be used in a vehicle, in particular for monitoring the surroundings of the vehicle.

[0029] A system may comprise the described optical sensor system and the third cover. The third cover may comprise the interface structure to which the optical sensor system may be attached via the second elastic cover. The described system may further be comprised in a vehicle.

[0030] In the vehicle environment it is advantageous to mount the optical sensor system at a location that is a high location of the vehicle, to obtain a good overview. This is especially true for optical sensors systems such as cameras and lidar systems. For design and aerodynamic reasons, it is advantageous to install the optical sensor systems behind the windshield of the vehicle. Here, the existing cleaning systems, e. g. wiper, and the existing heating for the windshield can also be used for the optical sensor system.

[0031] The described optical sensor system with the second cover allows to mount the optical sensor system behind the windshield of the vehicle. The windshield in front of optical sensor system may be attached to the optical sensor system using the second cover, which avoids a gap, so that optical damping avoided. Due to the elastic characteristic of the second cover surface roughness, surface waviness, curvature and angle of attack of the windshield may be evened out.

[0032] Brief description of the figures

[0033] Embodiments will now be described with reference to the attached drawing figures by way of example only. Like reference numerals are used to refer to like elements throughout. The illustrated structures and devices are not necessarily drawn to scale.

[0034] Fig. 1 schematically illustrates an optical sensor system.

[0035] Fig. 2 schematically illustrates an embodiment of a mounted optical sensor system.

[0036] Fig. 3 schematically illustrates another embodiment of a mounted optical sensor system.

[0037] Fig. 4 schematically illustrates a vehicle with the optical sensor system.

[0038] Detailed Description

[0039] Fig. 1 schematically illustrates an embodiment of an optical sensor system 10 comprising an optical reception device 12. The optical reception device 12 receives an optical signal L. Using the optical signal L the optical detection system 10 monitors a monitoring area 32. The optical detection system 10 may be a camera with an optical sensor receiving the optical signal L in the visible frequency range. The optical detection system 10 may also be a lidar system using laser light as an optical signal L. The lidar system additionally comprises an optical transmission device 26.

[0040] The optical sensor system 10 comprises a housing 11 to shield the components of the optical sensor system 10 like the optical reception device 12 from external influences and to allow a proper mounting of the optical sensor system 10. The housing comprises an aperture which is covered by a first cover 14. The aperture is designed to let the optical signal L pass. The first cover 14 is designed to be transparent for the optical signal L. The first cover is for example a rigid cover to shield the interior of the housing 11 with the optical reception device 12 for example, from mechanical impact.

[0041] The optical sensor system 10 comprises a second cover 16 which is elastic and also transparent for the optical signal L. The second cover 16 is designed to improve the connection of the first cover 14 with a third cover.

[0042] In the embodiment of Fig. 1 the third cover is an exterior cover 18 of the optical sensor system 10. The exterior cover 18 may for example also be a rigid cover. It may for example be a disk or a trim. It may be foreseen to further protect the optical detection system 10 from mechanical stress. It may also be foreseen to give the optical detection system an outer shape that is aligned with the design of the surroundings, e. g. in a vehicle 30.

[0043] The second cover 16 may be foreseen to fill a gap between a surface of the first cover 14 and a surface of the exterior cover 18. The second cover 16 comprises elastic material to be able to fully fill the gap without leaving spaces of gas. Filling the gap in between the first cover 14 and the exterior cover 18 allows to avoid a transition via air by the optical signal L. The second cover 16 comprises material which is optically transparent for a band around the wavelength of the optical signal L. At least those portions of the second cover 16 that are located in the optical path of the optical signal L are transparent for the optical signal L such that the optical sensor system may function to monitor the monitoring area 32.

[0044] In certain embodiments, e. g. for the optical signal L being in the infrared range, the second cover 16 may be transparent to infrared light while being opaque or less transparent to visible light. There is the further advantage, that in a gap between the first cover 14 and the exterior cover 18 that is filled with the elastic second cover 16, no microclimate may form and algae formation may be avoided. As the second cover is optically transparent at least in the band around the wavelength of the optical signal L, the optical path is not impaired. A further advantage is that mechanical measures such as rubber seals or vacuum sealing of the gap can be avoided. Additionally, tolerances or unevenness between the surfaces of the first cover 14 and the exterior cover 18 may be compensated. Due to the elasticity of the second cover 16 it can even adapt to different contours of the first cover 14 and the exterior cover 18 and therefore allow for more freedom of design and / or packaging.

[0045] In some embodiments, the refractive index of the first cover 14 and / or the exterior cover 18 may be matched by the refractive index of the second cover 16. In some embodiments the refractive indices of the exterior cover 18 and the first cover 14 are the same. The refractive index of the second cover may then be chosen to match the refractive indices of the first cover 14 and the exterior cover 18.

[0046] For the case that the materials of the first cover 14 and the exterior cover have different refractive indices or optical density, the refractive index of the second cover 16 may be selected such that it is in between the two refractive indices of the first cover 14 and the exterior cover 18. It may for example be chosen to be in the middle between the between the two refractive indices of the first cover 14 and the exterior cover.

[0047] Fig. 2 schematically illustrates an embodiment of an optical sensor system 10 mounted to a third cover, which is a windshield 20 of a vehicle 30. The windshield 20 is the front screen window of the vehicle 30. The second cover 16 is made of elastic adhesive material, like e. g. glue. The second cover may therefore serve to attach the first cover 14 of the optical sensor system 10 to the windshield 20. The material of the second cover 16 should also be as transparent as possible in the band of the wavelength of the optical signal L to be detected by the optical detection system 10.

[0048] For optical sensor systems 10 it is advantageous to be mounted in a position high in the vehicle 30. It is also advantageous to mount the optical sensor system 10 behind the windshield 20 of the vehicle 30 for design reasons and / or aerodynamic reasons. The optical sensor system 10 may benefit from the additional protection of the windshield 20. Also, the devices available for the windshield 20 like e. g. wiper and / or heating can be beneficial for the optical sensor system 10 as well.

[0049] At the same time, the second cover 16 has the advantage that it may minimize the attenuation of light by the windshield 20. This is particularly beneficial for lidar systems.

[0050] The second cover 16 comprises optically transparent material and is optically transparent in a band around the wavelength of the optical signal L. It is further located in the optical path of the optical signal L. As the transition over an air-filled gap is avoided is such a setup, reflections and the occurrence of total reflections between the optical sensor system 10 and the windshield 20 may be avoided.

[0051] In some embodiments, the refractive index of the first cover 14 and / or the windshield 20 may be matched by the refractive index of the second cover 16. In some embodiments the refractive indices of the windshield 20 and the first cover 14 are the same. The refractive index of the second cover may then be chosen to match the refractive indices of the first cover 14 and the windshield 20.

[0052] The material of the second cover 16 may for example be gel-like in nature, so that undulations and roughness of the surface on the inside of the windshield 20 can also be compensated. This may even allow to reduce the demands on the optical quality of the materials of e. g. the windshield 20 and / or the first cover 14. The material of the second cover 16 may for example be based on glycerine or silicone.

[0053] For the case that the materials of the first cover 14 and the windshield 20 have different refractive indices or optical density, the refractive index of the second cover 16 may be selected such that it is in between the two refractive indices of the first cover 14 and the windshield 20. It may for example be chosen to be in the middle between the between the two refractive indices of the first cover 14 and the windshield 20.

[0054] The optical sensor system 10 with the first cover 14 and the second cover 16 as described has the advantage that it may help improve optical damping of the optical sensor system attached to the windshield 20. It may also help mitigate surface roughness and waviness, curvature, and / or angle of attack of the windshield 20.

[0055] In other embodiments, the third cover may be in the grille of the vehicle 30, the trim, the headlights, the rear windows, the pillar covers, the side windows and / or similar. The described optical sensor system 10 may also comprise an interior monitoring system with the monitoring area within the vehicle 30.

[0056] Fig. 3 schematically illustrates an embodiment of an optical sensor system 10 mounted on the inside of a bumper 22 of a vehicle. The optical sensor system 10 may for example be mounted inside the trim of the bumper 22 and is configured to monitor the monitoring area outside the vehicle 30 using the optical signal L. The optical sensor system 10 is mounted to an interface structure 24 of the bumper 22. The interface structure 24 is the third cover in this embodiment. The interface structure 24 provides a mechanical interface on the inside of the trim of the bumper 22 to improve the coupling of the optical sensor system 10.

[0057] The second cover 16 fills the area in between the first cover 14 and the interface structure 24. The optical material of the second cover prevents the formation of a microclimate between the interface structure 24 and the optical sensor system 10 such that the space may be almost air and oxygen-free. This leads to a better optical characteristic of the first cover 14, the second cover 16 and the interface structure 24 in the optical path of the optical signal L.

[0058] The second cover 16 may for example be mounted by applying silicone gel like e. g. Wacker Sil Gel 612 or to vulcanize some kind of silicone rubber on the interface structure 24. In case air bubbles get trapped in the second cover 16 during assembly, they may be dissolved by pressing and diffusing through the Sil Gel.

[0059] Fig. 4 schematically illustrates the vehicle 30, for example a passenger car. The optical sensor system 10, e. g. a lidar system, as described with respect to the previous figures may be used in such a vehicle and may be arranged in a front area of the vehicle 30. The optical sensor system 10 comprises the optical transmission device 26, the optical reception device 12 and a control unit 28.

[0060] The optical transmission device 26 transmits the optical signal L into the monitoring area 32. The optical signal L incident from the monitoring area 32 is received by the optical reception device 12.

[0061] In the control unit 28, the transmitted and received optical signal L may be evaluated e. g. using time-of-flight measurements. The evaluation may serve to detect objects O in the monitoring area 32. The control unit 28 may also monitor and control the transmitting process in the transmission device 26 and the receiving process in the reception device 12. The optical sensor system 10 may for example be placed or integrated at the front of the vehicle 30. The monitoring area 32 is then located in front of the vehicle 30. Thus, in the example shown, an area in front of the vehicle 30 in the direction of travel can be monitored by the optical sensor system 10. There are also optical sensor systems 10 possible for other parts of the vehicle 30, e. g. for surroundview functions such as at the sides and / or rear of the vehicle 30. It is also possible to arrange several sensor systems 10 on the vehicle 30, in particular also in corner areas of the vehicle 30.

[0062] The optical sensor system 10 may be used to detect stationary or moving objects O in the monitoring area 32. Objects O may be vehicles, persons, animals, plants, obstacles, roadway unevenness, in particular potholes or stones, roadway boundaries, traffic signs, open spaces, in particular parking spaces, precipitation, or the like.

[0063] The optical sensor system 10 comprising a lidar system may provide an accurate and dense detection point cloud of the monitoring area 32 that can show the contour of objects O, making it a very valuable sensor for e. g. autonomous or semi- autonomous driving. Mounted in front of the vehicle 30, such a lidar system may e. g. detect lane markings, underrideable elevated objects like tunnels or overhead bridges and the like.

Claims

CLAIMS1. Optical sensor system (10) comprising an optical reception device (12) configured to receive an optical signal (L) over an optical path from a monitoring area (32), wherein the optical sensor system (10) is configured to monitor the monitoring area (32) using the optical signal (L), wherein the optical sensor system (10) further comprises a housing (11) with a first cover (14) and a second cover (16) arranged in the optical path, wherein the second cover (16) comprises elastic material.

2. Optical sensor system according to claim 1, wherein the first cover (14) and the second cover (16) are transparent with respect to a range of optical frequencies, wherein the range of frequencies is around the frequency of the optical signal (L).

3. Optical sensor system according to claim 1 or 2, wherein the second cover (16) is configured to be arranged in between the first cover (14) and a third cover (18, 20, 22) and to make an optical connection in between the first cover (14) and the third cover (18, 20, 22).

4. Optical sensor system according to one of the preceding claims, wherein the second cover (16) comprises adhesive material.

5. Optical sensor system according to one of the preceding claims, wherein the second cover (16) is configured to attach the optical sensor system (10) to the third cover (20, 22).

6. Optical sensor system according to claim 5, wherein the second cover (16) is configured to attach the optical sensor system (10) to an interface structure (24) of the third cover (22).

7. Optical sensor system according to claim 5 or 6, wherein the third cover (20, 22) comprises one of a windshield (20), a radiator grille, a bumper (22), a headlight, a window, or a pillar cover of a vehicle (30).

8. Optical sensor system according to one of the preceding claims, wherein the second cover (16) comprises silicone gel or silicone rubber.

9. Optical sensor system according to one of the preceding claims, wherein the first cover (14), the second cover (16) and / or the third cover (18, 20, 22) comprise a heating device.

10. Optical sensor system according to one of the preceding claims, wherein the refractive index of the second cover (16) is in between the refractive index of the first cover (14) and the refractive index of the third cover (18, 20, 22).

11. Optical sensor system according to one of the preceding claims, wherein the refractive index of the second cover (16) is roughly in the middle between the refractive index of the first cover (14) and the refractive index of the third cover (18, 20, 22).

12. Optical sensor system according to one of claims 1 to 6, wherein the refractive index of at least two of the covers (14, 16, 18, 20, 22) is the same.

13. Use of the optical sensor system (10) according to one of the preceding claims in a vehicle (30).

14. System comprising the optical sensor system (10) according to one of claims 1 to 12 and the third cover (18, 20, 22).

15. System comprising according to claim 14, wherein the third cover (22) comprises the interface structure (24).

16. Vehicle (30) comprising the system according to claim 14 or 15.

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