DE102016009926A1 - Lidar sensor device for a motor vehicle - Google Patents

Abstract

The invention relates to a lidar sensor device (12) for a motor vehicle (10) for scanning an ambient region (14) of the motor vehicle (10) by means of laser beams (L1, L2), with a transmitting device having a light source (16), the transmitting device to is adapted to emit laser beams (L1, L2) at predetermined angles into the surrounding area (14), receiving means (26) for receiving the laser beams (L1 ', L2') reflected in the surrounding area (14) and having a matrix arrangement (20) comprising a receiving region (E) with controllable microstructure elements (22) which are designed to transmit to the receiving device (26) the laser beams (L1 'L2') reflected in the surrounding region (14) along respective angles corresponding to the microstructure elements (22). to steer.

Description

The invention relates to a lidar sensor device for a motor vehicle for scanning an environmental region of the motor vehicle by means of laser beams, having a transmitting device comprising a light source, wherein the transmitting device is adapted to emit laser beams along predetermined angles in the surrounding area, and with a receiving device for receiving the in the surrounding area reflected laser beams.

It is already known from the prior art to arrange lidar sensor devices on a motor vehicle in order to monitor a surrounding area of the motor vehicle. Such lidar sensor devices may, for example, be laser scanners in which the surrounding area is scanned by deflecting a laser beam into the surrounding area at a different angle along each angle and thus illuminating a different partial area of the surrounding area at each measurement time. For deflecting the laser beam, such laser scanners usually have macroscopic mirrors which are deflected or swung out in at least one spatial direction by means of a motor. As a result, the laser beam can only be deflected along one angle into the surrounding area at each measurement time.

From the DE 10 2011 007 243 A1 is an optical system for the Umfassungsfassung with a laser for the generation of the intended for environment detection laser beam, in which in the beam path of the laser beam, a controllable phase grating with micromirrors or LCoS ("Liquid Crystal on Silicon") is arranged.

It is an object of the present invention to provide a solution as to how a lidar sensor device for a motor vehicle can be implemented in a particularly reliable, component-saving and cost-effective manner.

This object is achieved by a lidar sensor device according to claim 1. Advantageous embodiments of the invention are subject of the dependent claims, the description and the figures.

A lidar sensor device according to the invention for a motor vehicle is used for scanning a surrounding area of the motor vehicle by means of laser beams. The lidar sensor device comprises a transmitting device having a light source, wherein the transmitting device is adapted to emit laser beams at predetermined angles in the surrounding area, and receiving means for receiving the laser beams reflected in the surrounding area. In addition, the lidar sensor device comprises a matrix arrangement comprising a receiving area with controllable microstructure elements which are designed to direct the laser beams reflected in the surrounding area along respective angles corresponding to the microstructure elements to the receiving device.

The lidar sensor device serves to monitor the surrounding area of the motor vehicle. For this purpose, the transmitting device emits at least one laser beam along a predetermined angle or a predetermined transmission direction into the surrounding area at each measuring time, and the receiving device receives a part of the laser beam reflected by an object in the surrounding area. Based on a running time of the laser light, a distance of the object to the motor vehicle can be determined. The transmitting device has a light source, which comprises, for example, at least one laser diode.

For receiving the reflected laser beam from any desired direction or from any solid angle, it is passed through the receiving area of the matrix device back to the receiving device. In this case, the matrix arrangement has a multiplicity of microstructure elements arranged in rows and / or columns. At least one microstructure element of the receiving area, which corresponds to the respective receiving angle, is actuated, for example by a control device of the lidar sensor device, so that it can guide the at least one reflected laser beam from the surrounding area to the receiving device. For receiving, the receiving device has at least one receiving diode. The microstructure elements are formed, for example, as liquid crystal elements or micromirrors (MEMS, DMDs).

By means of the matrix arrangement is advantageously a fast and efficient reception of one or more laser beams at the same time possible.

The matrix arrangement particularly preferably has a transmitting region with controllable microstructure elements which are designed to form a laser beam from a respective part of the laser light emitted by the light source and strike the laser beam along a respective angle corresponding to the microstructure element to steer the surrounding area. For emitting the laser beam in the surrounding area of the transmission range of the matrix array of the Illuminated light source. In particular, the reception area is not illuminated by the light source. The light source preferably has at least one laser diode for emitting a laser beam and a lens element, wherein the lens element is designed to widen the laser beam emitted by the laser diode for illuminating the transmitting region of the matrix arrangement.

The matrix arrangement can thus comprise the transmission range and the reception range. The transmission range and the reception range can be separate regions of the matrix arrangement from one another, wherein the transmission range and the reception range can be formed, for example, by a plurality of mutually adjacent rows of the matrix arrangement. Alternatively, if the lidar sensor device is pulsed, the same microstructure elements may be used for transmission and reception so that the transmission area and the reception area are formed by the same area of the matrix array.

For emitting the laser beams at least one microstructure element of the transmission range, for example, by the control device, driven, so that a part of the laser light emitted from the light source is deflected as a laser beam along a certain transmission direction or a certain angle in the surrounding area. The transmission range thus serves to emit the parts of the laser light for generating a scanning movement or scanning movement along the different angles in the surrounding area. The angle of the currently emitted laser beam may, for example, be dependent on the currently active, controlled microstructure element. In this case, several microstructure elements can be activated simultaneously, so that simultaneously several laser beams are emitted along different angles into the surrounding area. Also, the angles can be generated by causing a phase shift of a respective part of the laser light by the one or more respective controlled microstructure elements. In the case of a plurality of driven microstructure elements, these parts of the laser light interfere according to the different phases to a laser beam, which is oriented along the desired angle or the desired transmission direction. The deflection of the laser beam is thus generated by the superposition of the parts of the laser light with the defined phases.

Thus, the matrix arrangement can be used both for emitting the laser beam and for receiving the reflected laser beam, whereby a fast and efficient deflection of one or more laser beams at the same time is made possible by means of the matrix arrangement. Thus, a particularly inexpensive and component-saving lidar sensor device can be provided. In addition, the polarization dependence of the microstructure elements configured as liquid crystal elements can be used to determine polarizing effects of detected objects. Thus, more in-depth information about the objects can be obtained and thereby classified, for example. In addition, information about wetness, ice, snow on and / or next to the roadway can be determined by the polarization dependence.

Particularly preferably, the light source has at least two laser diodes for emitting laser beams with different wavelengths. Thus, by using different wavelengths by means of the microstructure elements of the transmission range, several solid angles can be illuminated simultaneously. Alternatively or additionally, a range and an accuracy of the lidar sensor device can be optimized by adapting the wavelengths to the current weather conditions in the surrounding area of the motor vehicle.

In a preferred development of the invention, the lidar sensor device has a control device which is designed to set an attenuation of the laser beams, in particular during transmission, by driving the microstructure elements. In other words, the attenuation can be adjusted for each beam by means of the microstructure elements. The attenuation is regulated, for example, by the manner of the deflection of the laser light. For example, only a fraction of the laser light can be extracted from the transmitter and the remainder deflected into areas that absorb. Also, parts of the laser light can be canceled by destructive interference. A polarization rotation of the laser beam during emission is also possible, which is then correspondingly reduced by a downstream polarization filter. Due to the adjustable damping, a stronger laser can be installed in an advantageous manner and / or different lasers with different powers or wavelengths. Thus, the transmission power can be adjusted depending on the subarea of the surrounding area to which the transmission is made. This makes it possible, for example, to send stronger pulses in the far range than in the near range.

It proves to be advantageous if the receiving device has at least two receiving diodes. If, for example, by means of the microstructure elements of the transmission range, a plurality of laser beams are oriented in the surrounding area, different subranges of the Surrounding area to be illuminated simultaneously. As a result, different received signals, that is to say reflected laser beams from different spatial angles of the surrounding area, can be simultaneously received by means of the microstructure elements of the receiving area, fed to the receiving diodes of the receiving device and evaluated there. Thus, advantageously, different portions of the surrounding area can be scanned faster. These subareas can also be adapted to the situation and dynamically during a driving operation of the motor vehicle by activating the corresponding microstructure elements of the transmission range and the reception range. These subareas can be monitored with different accuracies and frequencies.

It can be provided that the microstructure elements are formed as transmissive liquid crystal elements, wherein the transmissive liquid crystal elements of the receiving area are adapted to transmit the laser beams reflected in the surrounding area to the receiving device. In the case where the microstructure elements are also used for transmission, the transmissive liquid crystal elements of the transmission area are designed to transmit respective parts of the laser light emitted by the light source as laser beams into the surrounding area. The microstructure elements here are thus transmissive elements, so-called LCs (LC "Liquid Crystal"), as they are known, for example, from LCD screens. In this case, the matrix arrangement is arranged in the propagation direction of the laser light emitted by the light source between the light source and the surrounding area or in the propagation direction of the reflected laser beam between the surrounding area and the receiving device.

Preferably, the microstructure elements are formed as reflective liquid crystal elements, wherein the reflective liquid crystal elements of the receiving area are adapted to reflect the laser beams reflected in the surrounding area to the receiving device. In the case where the microstructure elements are also used for transmission, the reflective liquid crystal elements of the transmission area are designed to reflect respective parts of the laser light emitted by the light source as laser beams into the surrounding area. Here the microstructure elements are reflective elements, so-called LCoS (Liquid Crystal on Silicon). According to this embodiment, the beam path is folded or kinked, so that a length of the beam path is shortened in an advantageous manner. Thus, a size of the lidar sensor device can be adapted to an available one of the installation space for the lidar sensor device on the motor vehicle.

In a particularly advantageous embodiment of the invention, a dispersive element is disposed in an optical path between the receiving device and the surrounding area, which allows filtering of interfering radiation in a simple manner. The dispersive element is designed in particular as an optical grating and / or prism. By means of the dispersive element, a dynamically programmable filter can be realized, which ensures an ideal background suppression of interference signals. Thus, the lidar sensor device can particularly reliably suppress background noise and detect objects in the surrounding area of the motor vehicle.

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or in the figures alone can be used not only in the respectively specified combination but also in other combinations or in isolation, without the scope of To leave invention.

Showing:

1 a schematic representation of a motor vehicle with a lidar sensor device; and

2 a schematic representation of an embodiment of a lidar sensor device according to the invention.

1 shows a motor vehicle 10 with a lidar sensor device 12 to monitor a surrounding area 14 of the motor vehicle 10 , To do this, the lidar sensor device sends 12 at least one laser beam L1, L2 along different angles or transmission directions in the surrounding area 14 and receives the objects in the environment area 14 reflected laser beams L1 ', L2' again. Based on a transit time of the laser beam L1, L1 ', L2, 12', a distance of the object to the motor vehicle 10 be determined. Based on the transmission angle, under which the laser beam L1, L2 in the surrounding area 14 , was sent, is also an orientation of the object with respect to the motor vehicle 10 known.

2 shows a schematic representation of an embodiment of the lidar sensor device 12 , The lidar sensor device 12 has one light source 16 on which laser light 18 to a transmission range S of a two-dimensional matrix arrangement 20 comprising a plurality of controllable microstructure elements 22 sending out. The light source has at least one laser diode which emits a laser beam. The emitted laser beam is in the direction of the matrix arrangement 20 widened. In this case, therefore, the lines forming the transmission range S of the matrix arrangement 20 fully lit, but not the entire matrix arrangement 20 ,

The microstructure elements 22 are designed here as LCoS and designed in an active state to a part of the laser light 18 as the laser beams L1, L2 along the LCoS corresponding angles in the surrounding area 14 to reflect. To activate the microstructure elements 22 become the corresponding microstructural elements 22 for example, by a control device 24 the lidar sensor device 12 controlled (in 2 indicated by a hatching) so that a desired phase change occurs, thereby the wavefront of the laser light 18 is moved accordingly and thus the laser beam L1, L2 is deflected along the respective angle. At the same time this can be done from the surrounding area 14 backscattered light, that is to say the reflected laser beams L1 ', L2', through a receiving region E of the matrix arrangement 20 to a receiving device 26 be redirected. The reception area E is from another, not from the light source 16 illuminated area of the matrix arrangement 20 educated.

If, in addition, a dispersive element (not shown here), for example a prism and / or a grating, is introduced into the optical path, then a programmable optical filter can be realized, which provides ideal suppression of background lighting, ie interference signals in the surrounding area 14 , guaranteed.

Since LCoS are usually very broadband, the light source can be 16 several laser diodes 28 . 30 have, wherein a first laser diode 28 emits a first laser beam having a first wavelength and a second laser diode 30 emits a second laser beam at a second wavelength. This allows different angle ranges in the surrounding area 14 be lit at the same time. Also can be made by the different wavelengths range optimization under different weather conditions. The. receiving device 26 can be at least two receiving diodes 32 . 34 have, so that reflected laser beams L1 ', L2' from different portions of the surrounding area 14 can be received, which temporally and spatially independent of the transmitter, so the light source 16 and the transmission range S, can be.

In summary, the lidar sensor device allows 12 through the use of the matrix arrangement 20 with the controllable microstructure elements 22 a fast and efficient deflection of one or more laser beams L1, L2 at the same time. At the same time, a reprogrammable optical filter with variable bandwidth and multiple central wavelengths can be realized. The surveillance areas to be scanned in the surrounding area 14 can be dynamically adapted to a driving situation, whereby several monitoring areas can be defined, which can be monitored with different accuracies and frequencies.

LIST OF REFERENCE NUMBERS

10

motor vehicle

12

Lidar sensor device

14

surrounding area

16

light source

18

laser light

20

matrix arrangement

22

liquid crystal element

24

control device

26

receiver

28, 30

laser diodes

32, 34

receiving diodes

L1, L2

laser beams

L1 ', L2'

reflected laser beams

S

transmission range

e

reception area

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102011007243 A1 [0003]

Claims (9)

Lidar sensor device ( 12 ) for a motor vehicle ( 10 ) for scanning a surrounding area ( 14 ) of the motor vehicle ( 10 ) by means of laser beams (L1, L2), with - a transmitting device having a light source ( 16 ), wherein the transmitting device is adapted to laser beams (L1, L2) along predetermined angles in the surrounding area ( 14 ), and - a receiving device ( 26 ) for receiving in the surrounding area ( 14 ) reflected laser beams (L1 ', L2'), characterized by a matrix arrangement ( 20 ) comprising a receiving region (E) with controllable microstructure elements ( 22 ), which are designed to be in the surrounding area ( 14 ) along respective ones, to the microstructure elements ( 22 ) corresponding angle reflected laser beams (L1 'L2') to the receiving device ( 26 ) to steer. Lidar sensor device ( 12 ) according to claim 1, characterized in that the matrix arrangement ( 20 ) a transmission range (S) with controllable microstructure elements ( 22 ), which are adapted from a respective, on at least one microstructure element ( 22 ) meeting the part of the light source ( 16 ) emitted laser light ( 18 ) to form a laser beam (L1, L2) and the laser beam (L1, L2) along a respective, to the microstructure element ( 22 ) corresponding angle in the surrounding area ( 14 ) to steer. Lidar sensor device ( 12 ) according to claim 2, characterized in that the light source ( 16 ) at least one laser diode ( 28 . 30 ) for emitting a laser beam and a lens element, wherein the lens element is adapted to the laser beam emitted by the laser diode for illuminating the transmitting region (S) of the matrix arrangement ( 20 ) expand. Lidar sensor device ( 12 ) according to claim 3, characterized in that the light source ( 16 ) at least two laser diodes ( 28 . 30 ) for emitting laser beams of different wavelengths. Lidar sensor device ( 12 ) according to one of the preceding claims, characterized in that the lidar sensor device ( 12 ) a control device ( 24 ), which is designed by driving the microstructure elements ( 22 ) to set an attenuation of the laser beams (L1, L2). Lidar sensor device ( 12 ) according to one of the preceding claims, characterized in that the receiving device ( 26 ) at least two receiving diodes ( 32 . 34 ) having. Lidar sensor device ( 12 ) according to one of the preceding claims, characterized in that the microstructure elements ( 22 ) are formed as transmissive liquid crystal elements, wherein the transmissive liquid crystal elements of the receiving region (E) are designed to be in the surrounding area ( 14 ) reflected laser beams (L1 ', L2') to the receiving device ( 26 ) to transmit. Lidar sensor device ( 12 ) according to one of claims 1 to 6, characterized in that the microstructure elements ( 22 ) are formed as reflective liquid crystal elements, wherein the reflective liquid crystal elements of the receiving area (E) are designed to be in the surrounding area ( 14 ) reflected laser beams (L1 ', L2') to the receiving device ( 26 ) to reflect. Lidar sensor device ( 12 ) according to one of the preceding claims, characterized in that in an optical path between the receiving device ( 26 ) and the surrounding area ( 14 ) is arranged a dispersive element for filtering interference radiation.

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