Sensor device for a motor vehicle

Abstract

Sensor device for arrangement on the inside of a window of a motor vehicle with at least one sensor for receiving and / or transmitting electromagnetic radiation, wherein the sensor device comprises a first housing module (1) for accommodating a computing unit and a second housing module (2) for accommodating the at least one sensor, the first and second housing modules are flexibly connected to each other via an adjustment unit (3), the adjustment unit (3) enables a three-dimensional alignment of the two housing modules (1, 2) relative to each other, characterized by the fact that in the second housing module (2) a lidar sensor consisting of a laser transmitter (7) and laser receiver (8) as well as a camera (9) is arranged, and the laser transmitter (7) is a pulsed laser consisting of a predetermined number of laser diodes connected to a stack, wherein the number of laser diodes is 5 to 10.

Description

[0001] The invention relates to a sensor device for arrangement on the inside of a window of a motor vehicle according to the preamble of claim 1.

[0002] In modern vehicles, electronic driver assistance systems help to prevent accidents and / or reduce their consequences. Most of these systems require information about the vehicle's surroundings, which is provided by various sensor technologies such as radar, ultrasound, lidar, and imaging systems using cameras.

[0003] For example, an adaptive cruise control system, such as ACC, requires information about the distance to a vehicle ahead and the relative speed between the two vehicles. Radar sensors are typically used to obtain this data about the vehicle ahead, measuring its distance and position.

[0004] Recently, the development has shifted away from expensive radar sensors towards lidar sensors, which consist of an infrared emitter, a photodiode to receive the emitted infrared light, and evaluation electronics. The sensor measures the time of flight of the emitted infrared beams, measuring the time it takes for the light to travel from the sensor to the vehicle ahead and back. From this time of flight, the evaluation electronics calculate the distance to the vehicle ahead, and the resulting electronic image is sufficient to distinguish objects. Because the lidar sensor can detect weather-related visibility limitations, driver warnings and speed adjustments are also based on this information.

[0005] In practice, the lidar-based ACC with a range of 250 m does not differ from conventional radar systems: The driver sets the desired vehicle speed, whereupon the vehicle maintains this speed until the lidar-based ACC detects a vehicle ahead in its lane. In this case, the speed is reduced to maintain a preset safety distance, whereby this safety distance is not an absolute distance, but rather a time interval between the vehicles.

[0006] A disadvantage of lidar-based systems for obtaining environmental data is the "electronic image" of the lidar sensor, which, due to its low resolution, ultimately only allows for distance measurement and an assumption about the object ahead. Further environmental information, such as lane markings and boundary lines, information about traffic signs at the edge of the road, object detection, etc., is not possible.

[0007] To improve such lidar-based environmental perception systems, it has been proposed to supplement the lidar system with an electronic camera; in other words, to create a combination of a lidar sensor and, for example, a CMOS camera in a single housing. Such a combined sensor was presented at the 2007 IAA by Siemens VDO (then Siemens VDO, now Continental AG). For the arrangement of such a lidar-camera sensor in a motor vehicle to obtain environmental data, German patent application DE 43 29 983 A1 proposes a roof module for the vehicle in which one or more sensors for receiving or transmitting optical and / or electromagnetic radiation are arranged. The roof module is positioned on the ceiling and on the inside of the windshield of the vehicle in such a way as to minimize interference with the driver's field of vision.The sensors are positioned so that the external radiation acting upon them is absorbed by the vehicle's windshield, or so that the sensors' radiation can be emitted outwards through the windshield. A preferred sensor placement is in the area of ​​the windshield at the height of the driver's rearview mirror, which is cleaned by the windshield wipers, in order to achieve optimal sensor performance.

[0008] A disadvantage of the known arrangement is that, due to the predetermined shape of the sensor module, too much installation space is required in the vehicle.

[0009] Publication US 2004 / 0196179 A1 relates to a reversing assembly comprising a mounting structure and a triband antenna module. The mounting structure is designed for installation on a conductive mounting knob attached to an inner surface of a vehicle windshield. The triband antenna module is mounted next to the conductive mounting knob and includes a patch antenna and a dual-band cellular antenna.

[0010] The publication DE 102 33 349 A1 relates to a sensor device for being arranged at a distance behind and facing a disc, such as the windshield of a motor vehicle, comprising a sensor arrangement with an opto-electronic sensor array and with a lens positioned in front of the sensor array in the recording direction, wherein the sensor arrangement is fixed by means of an intermediate guide for setting the distance of the sensor arrangement to the windshield and a spacer supported on the inside of the disc is assigned to the sensor arrangement.

[0011] German patent application DE 10 2005 014 961 A1 relates to a device with electronic components. Devices with electronic components such as sensors and cameras are combined into a module and positioned at a predetermined location on the windshield of a motor vehicle. The device can be attached to the roof structure of the motor vehicle in the roof area using a mounting element, the mounting element is connected to the module by means of a flexible connecting element, and the module can be fixed to the windshield using a positioning aid.

[0012] German patent application DE 10 2007 035 905 A1 relates to a sensor arrangement for a vehicle with at least one radiation-sensitive sensor and at least one capacitive sensor for detecting moisture. Information acquired by the at least one radiation-sensitive sensor and the at least one capacitive sensor is jointly evaluated by an evaluation device.

[0013] The invention is therefore based on the objective of creating a sensor device for arrangement on the inside of a motor vehicle window which requires less installation space.

[0014] This problem is solved by a sensor device having the features of claim 1. Preferred embodiments of the invention are the subject of the dependent claims.

[0015] A sensor device according to the invention, which is designed for arrangement on the inside of a window of a motor vehicle, comprises at least one sensor for receiving and / or transmitting electromagnetic radiation, wherein - the sensor device comprises a first housing module for receiving a computing unit and a second housing module (2) for receiving the at least one sensor, - the first and second housing modules are flexibly connected to each other via an adjustment unit, - the adjustment unit enables a three-dimensional alignment of the two housing modules relative to each other, - in the second housing module a lidar sensor consisting of a laser transmitter and laser receiver as well as a camera is arranged, and - the laser transmitter is a pulsed laser consisting of a predetermined number of laser diodes connected to a stack, where the number of laser diodes is 5 to 10.

[0016] This makes it advantageously possible to arrange the sensor device on the inside of a vehicle window with the smallest possible installation space.

[0017] Furthermore, the second housing module contains a lidar sensor consisting of a laser transmitter and a laser receiver, as well as a camera, for example a CMOS camera. The associated processing unit for evaluating the data recorded by the lidar sensor and the camera is located in the first housing module, and the necessary flexible connections for data transmission exist between the first and second housing modules.

[0018] The laser transmitter is formed by a pulsed laser composed of a predetermined number of laser diodes connected to each other in a stack. The number of laser diodes is preferably between 5 and 10. This large number of laser diodes increases the output laser power required to transmit the light from the lidar sensor through the vehicle's windshield to the outside, ensuring that sufficient reflected intensity remains for detection.

[0019] Preferably, the first housing module has a first fastening device for attaching the first housing module to the roof of the motor vehicle. The term "roof" also includes the front roof strut of the motor vehicle. The fastening device can be a screw connection or a clamp connection, and the type of connection is not considered a limitation.

[0020] Preferably, the second housing module has a second fastening device by means of which the second housing module is attached to the vehicle's windshield. In particular, the second fastening device can be designed to create an adhesive bond with the inside of the vehicle's windshield. It is also possible that the second fastening device is arranged on the adjustment unit, so that the adjustment unit is attached to the vehicle's windshield.

[0021] In a motor vehicle according to the invention, the sensor device is arranged on the inside of the windshield, with the first housing module being located on the roof rack and the second housing module being located on the windshield. Preferably, the sensor device is arranged in the area of ​​the driver's interior rearview mirror, the interior rearview mirror being able to be arranged on the mounting device of the shielding unit.

[0022] In this way, the required installation space is minimized by the flexible connection between the sensor module (i.e., the second housing module) and the processing unit (i.e., the first housing module). This flexible connection enables space-optimized integration within the vehicle and allows for movement in the X, Y, and Z directions. Connections are made, for example, via ball joints or flexible cables. Furthermore, the unit's modular design allows the lidar masking to be adapted to the windshield angle without requiring modifications to the other components. The adjustment unit mechanically adjusts the laser beam horizontally and vertically. The lidar masking shields the beam path from interference and prevents the laser beam from escaping into the vehicle interior through reflection off the windshield.

[0023] A preferred embodiment of the invention is explained below with reference to the drawings. The drawings show: Fig. 1 a perspective top view of the sensor device, Fig. 2 a view from below of the sensor unit, and Fig. 3 a side view from below, and Fig. 4 A schematic representation of a lidar laser diode.

[0024] Fig. Figure 1 shows a first housing module 1, which contains the processing unit, and a second housing module 2, which contains the optical sensors, which are flexibly connected to each other by means of an adjustment unit 3. The adjustment unit 3 is designed in the form of a support frame that is arranged between the first and second housing modules 1, 2 and flexibly connects them to each other.

[0025] The second housing module 2 contains a laser transmitter 7, a laser receiver 8, and a camera 9, for example, a CMOS camera, which, when installed, face forward towards the windshield. The adjustment unit 3 allows the sensors 7, 8, and 9 to be aligned with the windshield and thus with the road in front of the vehicle. Furthermore, the sensor unit includes a shielding unit 4, which is connected to the second housing module 2. The design of the shielding unit 4 is a function of the angle and surface of the windshield.

[0026] The first housing module 1 has a first mounting device 5 by which the first housing module 1 is positioned on the roof (not shown) or on the front roof crossmember (not shown). Furthermore, the second housing module 2 has a second mounting device 6 by means of which the second housing module, i.e., the sensor unit, is attached to the windshield from the inside. For example, the attachment can be made by means of an adhesive bond, so that the surface of the second mounting device is designed accordingly to allow an adhesive bond to the windshield of the vehicle. Furthermore, the shielding device 4 has lateral struts 10 and 11 that prevent laser light from escaping laterally from the device and entering the passenger compartment. Inside the shielding device 4, further internal struts 12 and 13 are arranged, which prevent crosstalk of the light between the three sensors.

[0027] Furthermore, cables 14 are shown, which run from the processing unit to the driver assistance system and from the interior mirror to its control unit. Adjustment screws 15 are also indicated, by means of which the first and second housing modules 1, 2 can be adjusted relative to each other.

[0028] Fig. Figure 2 shows the component from below, including the first housing module 1, the second housing module 2, the connecting adjustment unit 3, and the shielding unit 4. The mounting device 6 for attaching the second housing module 2 to the windshield (not shown) is also visible. Furthermore, one of the lateral shielding struts 10 of the shielding unit 4 and the adjustment screws 15 of the adjustment unit 3 are visible. Since the computer unit located in the first housing module 1 generates waste heat, the underside of the first housing module 1 is provided with cooling fins 17.

[0029] Furthermore, a bracket 16 is shown on the underside of the shield 4, to which the driver's side interior mirror (not shown) of the motor vehicle can be attached.

[0030] Fig. Figure 3 shows the device in a side view with the first housing module 1 for accommodating a processing unit (not shown), which is arranged on the front roof crossmember 18 of the inner roof surface 19 of the vehicle, as well as the adjustment unit 3 and the second housing module 2 arranged behind it for accommodating the sensors (not shown). Also shown schematically are two adjustment screws 15 for aligning the second housing module 2 and thus the sensors. Furthermore, the shielding unit 4, in particular the lidar mask made of plastic, can be seen from the side. The second housing module 2 is attached to the windshield by means of the second fastening device 6.

[0031] Fig.Figure 4 shows a schematic representation of the laser diode 20 used, which is designed in the form of a stack consisting of a plurality of stack elements 21, with eight stack elements 21 shown here. Laser activity occurs in the optically active zones 22, i.e., the emission of laser beams 23. The arrangement of a plurality of stack elements 21 leads to an increase in the power of the laser diode 20, which is required to transmit sufficient laser power through the front window and to receive correspondingly sufficient reflected power. REFERENCE MARK LIST 1 first housing module 2 second housing module 3 Adjustment unit 4 Shielding unit 5 first fastening device 6 second fastening device 7 laser transmitters 8 laser receivers 9 Camera 10 side bridge 11 lateral bridge 12 inner bridge 13 inner bridge 14 cables 15 adjusting screws 16 bracket 17 cooling fins 18 roof crossbeams 19 Roof interior 20 laser diode 21 stack elements 22 optically active zones 23 Laser activity

Claims

[1] Sensor device for arrangement on the inside of a window of a motor vehicle with at least one sensor for receiving and / or transmitting electromagnetic radiation, wherein the sensor device comprises a first housing module (1) for accommodating a computing unit and a second housing module (2) for accommodating the at least one sensor, the first and second housing modules are flexibly connected to each other via an adjustment unit (3), the adjustment unit (3) enables a three-dimensional alignment of the two housing modules (1, 2) relative to each other, characterized by , that in the second housing module (2) a lidar sensor consisting of a laser transmitter (7) and laser receiver (8) as well as a camera (9) is arranged, and the laser transmitter (7) is a pulsed laser consisting of a predetermined number of laser diodes connected to a stack, wherein the number of laser diodes is 5 to 10. [2] Sensor device according to claim 1, characterized by , that the first housing module (1) has a first fastening device (5) for fastening the first housing module (2) to the roof of the motor vehicle. [3] Sensor device according to one of claims 1 or 2, characterized by , that the sensor device has a second fastening device (6) for fastening the second housing module (2) or the adjustment unit (3) to the windshield of the motor vehicle. [4] Sensor device according to any of the preceding claims, characterized by , that a shielding unit (4) is arranged on the second housing module (2) and rests against the disc to shield against stray light. [5] Sensor device according to claim 4, characterized by , that the shielding unit (4) has a fastening device (16) for attaching an interior rearview mirror. [6] Motor vehicle with a sensor device according to one of the preceding claims, characterized by, that the sensor device is arranged on the inside of the windshield, wherein the first housing module (1) is arranged on the roof rack and the second housing module (2) is arranged on the windshield. [7] Motor vehicle according to claim 6, characterized by , that the sensor device is arranged in the area of ​​the interior rearview mirror for the driver, wherein the interior rearview mirror is arranged on a mounting device (16) of the shielding unit (4).

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