OPTICAL SENSOR SYSTEM

Abstract

The present disclosure relates to an optical sensor system (10) comprising an optical receiving device (12) designed to receive an optical signal (L) via an optical path from a monitoring area (32), wherein the optical sensor system (10) is designed to monitor the monitoring area (32) using the optical signal (L), and 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, the second cover (16) comprising an 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

Technical FieldThe 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 including the optical sensor system and a vehicle.BackgroundModern vehicles such as cars, vans, trucks, motorcycle, etc. may include sensor systems whose data is used for driver information and / or used by driver assistance systems.Sensor systems are continually being developed for various functions, e.g., for the detection of environmental information in the near and far area of vehicles, such as passenger cars or commercial vehicles. Based on the acquired data, a model of the vehicle environment may be generated, and a response to changes in that vehicle environment is possible. Sensor systems can also serve as sensors for driver assistance systems, in particular assistance systems for autonomous or semi-autonomous vehicle control. They can be used, for example, to detect obstacles and / or other road users in front of, behind the vehicle or in its blind spot.An important principle of an optical sensor for detecting the environment, for example of vehicles, is lidar technology (lidar: light detection and distance measurement). A lidar system includes an optical transmission device and an optical receiving device. The transmission device emits an optical signal, which may be continuous or pulsed. Moreover, the optical signal may be modulated. For example, electromagnetic waves in the form of laser beams in the ultraviolet, visible or infrared range can be used as optical signals in a lidar system. The light is received by the optical receiving device after reflection from an object in a monitoring region of the lidar system. The optical signal can be evaluated, for example, according to a runtime method, and the spatial position and the distance of the object at which the reflection occurred can be determined. In addition, it may be possible to determine a relative speed. Reflection or reflected light is understood herein to mean any light that is reflected back, and in particular is also intended to include light that is reflected back by scattering or absorption emission. Another example of an optical sensor system is the capture of images by a camera.SummaryAn optical sensor system comprises an optical receiving device configured to receive an optical signal from a monitoring area via an optical path, the optical sensor system configured to monitor the monitoring area using the optical signal, the optical sensor system further comprising a housing having a first cover and a second cover disposed in the optical path, the second cover comprising an elastic material.The optical sensor system may comprise a camera. The optical receiving device may include 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.The second cover comprising the elastic material allows tolerances between the first pane and any other surfaces to be compensated and adapted to different contours.The housing can be designed to protect the components of the optical sensor system from environmental influences such as dust, moisture, wind. The optical signal of the optical sensor system is transmitted and / or received via an opening in the housing which is covered by the first cover. The first cover may comprise a material that transmits the optical signal, such as plastic or glass. The first cover may comprise a rigid material to improve the mechanical stability of the housing and to adequately protect the components of the optical sensor system.The second cover is disposed in the optical path of the optical signal and is preferably attached to the first cover facing outward from the housing. The resiliency of the second cover allows the optical sensor system to be disposed proximate a third cover, which may include a hard surface, wherein a gap between the first cover and the third cover may be avoided. A possible gap between the first cover and the third cover may be filled with the elastic second cover. The elasticity of the second cover may allow the gap to be filled. This avoids the transmission of the optical signal over air between the first and third covers. This reduces attenuation in the optical path since reflections and total reflections can be reduced.The second cover further enables the gap to be avoided, which can prevent dirt, condensation, algae formation, and the like from forming between the first cover and the third cover. Avoiding the gap may avoid interference in the optical path and reflections between the first cover and the third cover. This can improve the optical detection quality. Also, ghosting and blooming can be avoided.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, the range of frequencies being approximately at the frequency of the optical signal. Both the first and the second cover are arranged in the optical path. In addition, they are specifically configured to pass the optical signal. Other frequencies of the electromagnetic radiation may be blocked or attenuated. For example, the first and / or second cover may be configured to block ambient light from outside the housing. Thus, the housing with the first and second covers can shield the optical sensor system from ambient light.In some embodiments, the second cover may be mixed with a material that makes it transparent to certain ranges of frequencies and opaque to others. The opacity and transparency to 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 to visible light or less transparent. Such an embodiment is particularly useful for embodiments where the optical signal is in the infrared range. The second cover can then additionally serve the purpose of an optical filter, a shutter and / or provide thermal insulation. At the same time, the first cover may be transparent to both IR and visible frequency ranges.Due to the resilient nature of the second cover, additional mechanical measures such as rubber seals or vacuum sealing may not be necessary, which helps reduce costs.In an embodiment of the optical sensor system, the second cover is configured to be arranged between the first cover and a third cover and to establish an optical connection between the first cover and the third cover. The third cover may be provided to additionally protect the optical sensor system, for example, or may be provided for design reasons, for example. The third cover may include, for example, another protection window in front of the second cover. In this embodiment, the housing may include the first, second, and third covers. The second cover with its elastic material makes it possible to prevent a gap, e.g. filled with air, from forming between the first and the third cover. This makes it possible to realize the advantages as described above.In an embodiment of the optical sensor system, the second cover comprises an adhesive material. The properties of the material contained in the second cover provide the ability of the second cover to pass the optical signal path, but also provide adhesion quality. This gives flexibility to the use of the optical sensor system and also to the manner in which it is fastened in its environment, for example a vehicle.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 with the adhesive property, this allows for a simple 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 property of passing the optical signal path.The resilient second cover may provide additional shielding of the optical sensor system from mechanical forces such as vibrations.The second cover may be configured to attach the optical sensor system to an interface structure of the third cover. The interface structure includes a mechanical interface structure that mechanically connects the optical sensor system to the third cover. It provides the geometry and dimension to connect the optical sensor system to the third cover. It can also be located in the optical path of the optical sensor system and can therefore be optically transparent.The interface structure may provide a suitable structure to make the attachment of the optical sensor system easy, e.g. by providing a surface to which the optical sensor system may be easily attached, e.g. by adhesion. It may also provide other methods of simple attachment, e.g. assist attachment with screws, bolts or the like. The interface structure may also provide a surface to which the optical sensor system may be easily and / or accurately aligned with the proper position and shielded from undesirable mechanical forces such as vibrations.The third cover may include one of a windshield, a grille, a bumper, a headlamp, a window, or a pillar cover of the vehicle. The second cover being disposed between the third cover and the first cover makes it possible to avoid the gap between the first and third covers. If the second cover provides adhesive properties, it allows for easy attachment of the optical sensor system to the third cover.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 covers, and at the same time may provide sufficient optical transmission. They can provide additional adhesive properties. The silicone rubber may be vulcanized during the manufacturing process or upon attachment of the optical sensor system. The silicone gel may be, for example, a Wacker Sil Gel 612.In an embodiment of the optical sensor system, the first cover, the second cover and / or the third cover comprise a heating device.For example, for use in a vehicle, this may provide a convenient clear view even under poor temperature conditions. Possible heating devices that may be provided to free the optical sensor system from snow, ice or the like may be provided flexibly on the first, second and / or third cover, depending on what is most suitable for the task. For embodiments in which the third cover comprises, for example, a windshield or window or headlight of the vehicle, the heating device already provided in the third cover may be used.In an embodiment of the optical sensor system, the optical refractive index of the second cover is between the optical refractive index of the first cover and the optical refractive index of the third cover. For example, the refractive index of the second cap may be approximately midway between the refractive index of the first cap and the refractive index of the third cap. Reflections and total reflections between the first and third covers may be reduced. This helps reduce the attenuation introduced by the first, second and third covers in the optical path.In an embodiment of the optical sensor system, the refractive index of at least two of the covers is the same. If the refractive indices of two or three of the covers match, the attenuation of the optical signal introduced by the combination of the first, second and third covers in the optical path can be reduced. In addition, reflections and total reflections between the first and third covers may be reduced.The optical sensor system described can be used in a vehicle, in particular for monitoring the environment of the vehicle.A system may include the described optical sensor system and the third cover. The third cover may include the interface structure to which the optical sensor system may be attached via the second elastic cover. The described system may be further included in a vehicle.In the vehicle environment, it is advantageous to mount the optical sensor system at a location that is high on the vehicle in order to obtain a good overview. This applies in particular to optical sensor 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. windscreen wipers, and the existing heater for the windscreen may also be used for the optical sensor system.The described optical sensor system with the second cover enables the optical sensor system to be fastened behind the windshield of the vehicle. The windshield in front of the optical sensor system may be attached to the optical sensor system using the second cover, which avoids a gap, so that optical attenuation is avoided. Due to the elastic property of the second cover, surface roughness, surface curl, curvature, and angle of attack of the windshield may be compensated.Brief Description of the FiguresEmbodiments will now be described by way of example only with reference to the appended drawing figures. Similar reference numerals are used throughout to refer to similar elements. The illustrated structures and devices are not necessarily drawn to scale. FIG. 1 schematically illustrates an optical sensor system. FIG. 2 schematically illustrates an embodiment of an attached optical sensor system. FIG. 3 schematically illustrates another embodiment of an attached optical sensor system. FIG. 4 schematically illustrates a vehicle with the optical sensor system.DETAILED DESCRIPTIONFIG. 1 schematically illustrates an embodiment of an optical sensor system 10 that includes an optical receiving device 12. The optical receiving 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 having an optical sensor that receives the optical signal L in the visible frequency range. The detection optical system 10 may also be a lidar system using laser light as an optical signal L. The lidar system additionally includes an optical transmission device 26.The optical sensor system 10 comprises a housing 11 for shielding the components of the optical sensor system 10, like the optical receiving device 12, from external influences and for enabling a convenient attachment of the optical sensor system 10. The opening is configured to pass the optical signal L. The first cover 14 is configured to be transparent to the optical signal L. The first cover is, for example, a rigid cover for shielding the interior of the housing 11 with the optical receiving device 12 from, for example, mechanical interference.The optical sensor system 10 comprises a second cover 16 which is elastic and also transparent to the optical signal L. The second cover 16 is configured to enhance the connection of the first cover 14 to a third cover.In the embodiment of FIG. 1, the third cover is an outer cover 18 of the optical sensor system 10. It may be, for example, a pane or a cladding. It can be provided that the optical detection system 10 is further protected from mechanical stress. It may also be provided to give the optical detection system an external shape that is aligned with the design of the environment, e.g., in a vehicle 30.The second cover 16 may be provided to fill a gap between a surface of the first cover 14 and a surface of the outer cover 18. The second cover 16 includes an elastic material to be able to completely fill the gap without leaving gas spaces. Filling the gap between the first cover 14 and the outer cover 18 allows to avoid a transition over air by the optical signal. The second cover 16 includes a material that is optically transparent to a band at about the wavelength of the optical signal L. At least those portions of the second cover 16 that are in the optical path of the optical signal L are transparent to the optical signal L, so that the optical sensor system can serve to monitor the monitoring area 32.In certain embodiments, e.g., when the optical signal L is in the infrared range, the second cover 16 may be transparent to infrared light while being opaque to visible light or less transparent.There is another advantage in the sense that microclimate cannot be formed in a gap between the first cover 14 and the outer cover 18 filled with the elastic second cover 16, and algae formation can be prevented. Since the second cover is optically transparent at least in the band at about the wavelength of the optical signal L, the optical path is not affected. A further advantage is that mechanical measures such as rubber seals or vacuum sealing of the gap can be avoided. In addition, tolerances and asperities between the surfaces of the first cover 14 and the outer 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 outer cover 18 and thus allow more freedom in design and / or packaging.In some embodiments, the refractive index of the first cover 14 and / or the outer cover 18 may match the refractive index of the second cover 16. In some embodiments, the refractive indices of the outer 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 outer cover 18.In the event that the materials of the first cover 14 and the outer cover have different indices of refraction or optical density, the index of refraction of the second cover 16 may be selected to be between the two indices of refraction of the first cover 14 and the outer cover 18. It can be chosen, for example, such that it lies in the middle between the two refractive indices of the first cover 14 and the outer cover.FIG. 2 schematically illustrates an embodiment of an optical sensor system 10 attached to a third cover, which is a windshield 20 of a vehicle 30. The windshield 20 is the front windshield of the vehicle 30, and the second cover 16 is made of an elastic adhesive material, such as adhesive. 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 detection optical system 10.For optical sensor systems 10, it is advantageous that they are fastened at the top in the vehicle 30. It is also advantageous to secure the optical sensor system 10 behind the windshield 20 of the vehicle 30 for design and / or aerodynamic reasons. The optical sensor system 10 may benefit from the additional protection of the windshield 20. In addition, the devices available for the windshield 20, such as windshield wipers and / or heater, may also be advantageous for the optical sensor system 10.At the same time, the second cover 16 has the advantage of minimizing attenuation of light by the windshield 20. This is particularly advantageous for lidar systems.The second cover 16 comprises an optically transparent material and is optically transparent in a band at about the wavelength of the optical signal L. It is also located in the optical path of the optical signal L. Since the transition across an air-filled gap in such a setup is avoided, reflections and the occurrence of total reflections between the optical sensor system 10 and the windshield 20 can be avoided.In some embodiments, the refractive index of the first cover 14 and / or the windshield 20 may match 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.The material of the second cover 16 may be gel-like, for example, so that undulations and the roughness of the surface on the inside of the windshield 20 may also be compensated. This may even allow the optical quality demands of the materials of, e.g., the windshield 20 and / or the first cover 14 to be reduced. The material of the second cover 16 may be based on, for example, glycerin or silicone.In the event that the materials of the first cover 14 and the windshield 20 have different indices of refraction or optical density, the index of refraction of the second cover 16 may be selected to be between the two indices of refraction of the first cover 14 and the windshield 20. It can be chosen, for example, such that it lies in the middle between the two refractive indices of the first cover 14 and the windshield 20.The optical sensor system 10 having the first cover 14 and the second cover 16 as described has the advantage that it may help improve the optical attenuation of the optical sensor system attached to the windshield 20. It may also help reduce surface roughness and curl, curvature, and / or angle of attack of the windshield 20.In other embodiments, the third cover may be located in the grille of the vehicle 30, the trim, the headlights, the rear windows, the pillar covers, the side windows, and / or the like. The described optical sensor system 10 may also include an interior monitoring system having the monitoring area within the vehicle 30.FIG. 3 schematically illustrates an embodiment of an optical sensor system 10 mounted to the inside of a bumper 22 of a vehicle. For example, the optical sensor system 10 may be mounted within the fairing 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 attached 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 to the inside of the fairing of the bumper 22 to improve the coupling of the optical sensor system 10.The second cover 16 fills the area 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 results in a better optical property of the first cover 14, the second cover 16 and the interface structure 24 in the optical path of the optical signal L.The second cover 16 may be attached to the interface structure 24 by, for example, applying silicone gel such as Wacker Sil Gel 612 or vulcanizing some type of silicone rubber. If air bubbles are trapped in the second cover 16 during assembly, they may be dissolved by being pushed and scattered by the silicone gel.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 reference to the previous figures, may be used in such a vehicle and may be disposed in a front region of the vehicle 30. The optical sensor system 10 comprises the optical transmission device 26, the optical receiving device 12 and a control unit 28.The optical transmission device 26 transmits the optical signal L to the monitoring area 32, and the optical signal L incident from the monitoring area 32 is received by the optical reception device 12.In the control unit 28, the transmitted and received optical signal L can be evaluated, for example using runtime measurements. The evaluation can serve to detect objects O in the monitoring region 32. The control unit 28 may also monitor and control the transmission process in the transmission device 26 and the reception process in the reception device 12.The optical sensor system 10 may be placed or integrated, for example, at the front of the vehicle 30. The monitoring area 32 is then located in front of the vehicle 30, and 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. Other optical sensor systems 10 for other parts of the vehicle 30, e.g. for surround view functions, such as on the sides and / or on the rear side of the vehicle 30, are also possible. It is also possible to arrange a plurality of sensor systems 10 on the vehicle 30, in particular also in corner regions of the vehicle 30.The optical sensor system 10 may be used to detect stationary or moving objects O in the monitoring area 32. Objects O can be vehicles, persons, animals, plants, obstacles, unevenness of the road, in particular holes or stones, road boundaries, traffic signs, open spaces, in particular parking spaces, precipitation or the like.The optical sensor system 10, including a lidar system, may provide an accurate and dense detection point cloud of the monitoring area 32 that may show the contour of objects O, making it a very valuable sensor for, e.g., autonomous or semi-autonomous driving. For example, mounted to the front of the vehicle 30, such a lidar system may detect lane markings, underrunable raised objects such as tunnels or transfer bridges, and the like.

Claims

An optical sensor system (10) comprising an optical receiving device (12) configured to receive an optical signal (L) from a monitoring area (32) via an optical path, the optical sensor system (10) being configured to monitor the monitoring area (32) using the optical signal (L), the optical sensor system (10) further comprising a housing (11) having a first cover (14) and a second cover (16) disposed in the optical path, the second cover (16) comprising an elastic material.The optical sensor system of claim 1, wherein the first cover (14) and the second cover (16) are transparent to a range of optical frequencies, the range of frequencies being at about the frequency of the optical signal (L).The optical sensor system according to claim 1 or 2, wherein the second cover (16) is configured to be disposed between the first cover (14) and a third cover (18, 20, 22) and to establish an optical connection between the first cover (14) and the third cover (18, 20, 22).The optical sensor system of any preceding claim, wherein the second cover (16) comprises an adhesive material.The optical sensor system of any preceding claim, wherein the second cover (16) is configured to attach the optical sensor system (10) to the third cover (20, 22).The optical sensor system of 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).The optical sensor system of claim 5 or 6, wherein the third cover (20, 22) comprises one of a windshield (20), a grille, a bumper (22), a headlamp, a window, or a pillar cover of a vehicle (30).The optical sensor system of any preceding claim, wherein the second cover (16) comprises silicone gel or silicone rubber.The optical sensor system of any preceding claim, wherein the first cover (14), the second cover (16), and / or the third cover (18, 20, 22) comprise a heater.The optical sensor system of any preceding claim, wherein the refractive index of the second cover (16) is between the refractive index of the first cover (14) and the refractive index of the third cover (18, 20, 22).The optical sensor system of any preceding claim, wherein the refractive index of the second cover (16) is approximately midway between the refractive index of the first cover (14) and the refractive index of the third cover (18, 20, 22).The optical sensor system of any 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.Use of the optical sensor system (10) according to one of the preceding claims in a vehicle (30).A system comprising the optical sensor system (10) of any one of claims 1 to 12 and the third cover (18, 20, 22).The system of claim 14, wherein the third cover (22) comprises the interface structure (24).A vehicle (30) comprising the system of claim 14 or 15.

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