Lidar system and method for detecting surroundings
The lidar system with an inclined polygon mirror addresses the challenge of compact design and large detection range, improving vehicle environmental sensing for autonomous driving by enabling a larger detection area and field of view.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- VALEO SCHALTER & SENSOREN GMBH
- Filing Date
- 2026-01-13
- Publication Date
- 2026-07-23
AI Technical Summary
Existing lidar systems face challenges in achieving a compact design while maintaining a large detection range and efficient environmental sensing capabilities, particularly for vehicles requiring precise obstacle detection and autonomous driving functions.
A lidar system utilizing a polygon mirror with inclined mirror surfaces relative to the axis of rotation, allowing for oblique deflection of optical signals, which enables a compact design and increased detection range without altering the transmitting and receiving equipment.
The system achieves a larger detection area and field of view, enhancing the vehicle's environmental sensing capabilities, particularly for autonomous or semi-autonomous driving functions, while maintaining a compact form factor suitable for installation in vehicles.
Smart Images
Figure EP2026050657_23072026_PF_FP_ABST
Abstract
Description
[0001] 2023PF01560 1
[0002] LIDAR SYSTEM AND ENVIRONMENTAL SENSING METHOD
[0003] Technical field
[0004] The application relates to a lidar system for a vehicle and to a vehicle that incorporates such a lidar system. The application further relates to a method for environmental sensing using a lidar system.
[0005] background
[0006] Modern vehicles (cars, vans, trucks, motorcycles, etc.) are equipped with a multitude of sensor systems whose data serves to inform the driver and / or provide data to driver assistance systems. These sensor systems detect the vehicle's surroundings, including other road users. Based on the collected data, a model of the vehicle's environment can be created, and the system can react to changes in this environment.
[0007] Sensor systems are constantly being developed for various functions, such as environmental sensing in the near and far range of vehicles, including passenger cars and commercial vehicles. Sensor systems can also be used for driver assistance systems, particularly those for autonomous or semi-autonomous vehicle control. They can be used specifically for detecting obstacles and / or other road users in the front, rear, or blind spot areas of a vehicle. Sensor systems can be based on various sensor principles, such as radar, ultrasound, optics, etc.
[0008] An important optical sensor principle for environmental perception, e.g., of vehicles, is lidar technology (Lidar stands for Light Detection and Ranging). A lidar system has an optical transmitter and an optical receiver. The transmitter can emit an optical signal in the form of light, which can be continuous or pulsed. The optical signal can also be modulated. In a lidar system, optical signals in the form of laser beams in the ultraviolet, visible, or infrared range can be used. The receiver can detect the optical signal after reflection at a point in the vicinity of the lidar system.
[0009] The received optical signal can be evaluated using the transmitted optical signal, for example, by a time-of-flight method, and the spatial location and distance of the point where the reflection occurred can be determined. In this context, reflection or reflected light is understood to mean any light that is thrown back and is specifically intended to include light thrown back by scattering or absorption-emission.
[0010] The reflected optical signal can be detected in the receiving device via a receiving sensor. Receiving sensors of lidar systems can have several receiving elements, called pixels, for opto-electrical conversion. The pixels can be configured to receive optical signals from different reception angles.
[0011] Scanning lidar systems emit optical signals that move in a scanning direction. This scanning motion can be achieved by deflecting the optical signal transmitted by the optical transmitter using a deflection device, such as a polygon mirror. The deflection of the light can be effected, for example, by rotating the polygon mirror. US11933894B2 describes a lidar system with a polygon mirror whose mirror surfaces are inclined to the axis of rotation. The mirror surfaces are used for emitting light. Optionally, the transmitted and received light can be reflected off the same mirror surface.
[0012] German patent DE102022122223A1 describes a lidar system in which a polygon mirror is arranged between the transmitting and receiving devices. A scanning of a detection area can be achieved by rotating the mirror surfaces of the polygon mirror.
[0013] Overview
[0014] A lidar system for a vehicle comprises an optical transmitter, an optical receiver, and a polygon mirror. The optical transmitter is configured to transmit an optical signal along a transmit path. The optical receiver is configured to receive the optical signal along a receive path. The polygon mirror has side faces and two opposing base faces, each also formed as a polygon. The polygon mirror is rotatable about an axis of rotation passing through the base faces. 2023PF01560 3
[0015] The axis of rotation can optionally extend through a continuation of the respective base surface, which lies on the same plane as the base surface but outside the polygon's mirror image. In particular, the axis of rotation can be perpendicular to the base surfaces.
[0016] One of the side surfaces has a first mirror surface configured to deflect the optical signal on the transmission path to a detection area, and a second of the side surfaces has a second mirror surface configured to deflect the optical signal on the reception path away from the detection area. At least one of the mirror surfaces is inclined to the axis of rotation.
[0017] Optionally, more than two and / or all faces of the polygonal mirror can have a reflective surface. The polygonal mirror is designed to perform a rotational movement around its axis of rotation. This rotational movement can be a complete rotation while maintaining the direction of rotation. Alternatively, the rotational movement can be a pivoting movement. In a pivoting movement, the polygonal mirror is moved back and forth between two deflections, thus changing the direction of rotation. The at least one reflective surface that exhibits an inclination relative to the axis of rotation can be, for example, the first reflective surface and / or the second reflective surface.
[0018] The polygon mirror can also be called a rotating mirror. The optical signal on the transmit and receive paths is reflected by different mirror surfaces. At least one of the mirror surfaces of the polygon mirror is inclined to the axis of rotation. The optical signal deflected by the mirror surface that is inclined relative to the axis of rotation is reflected obliquely. If the inclined mirror surface is in the transmit path, the optical signal is transmitted obliquely into the detection area. If the inclined mirror surface is in the receive path, the optical signal is received obliquely from the detection area. The detection area of the lidar system is modified accordingly and can be increased, in particular, by the inclination.
[0019] The detection range can therefore be increased by adjusting the inclination of the mirror surfaces, without changing the design of the transmitting and / or receiving equipment. For some applications, the transmitting and / or receiving equipment can be made more compact and, for example, suitable for a 2023PF01560 4
[0020] A smaller detection range can be designed. However, the tilt allows for a larger detection range despite a compact design of the transmitting and / or receiving equipment.
[0021] The detection area corresponds to the field of view (FoV) of the lidar system and encompasses the points detected by the optical signal within the lidar system's environment. The detection area can also be referred to as the monitoring area.
[0022] In one embodiment of the lidar system, the polygon mirror is positioned between the transmitting and receiving units. This allows the lidar system to be implemented in a compact design with a large detection range.
[0023] In one embodiment of the lidar system, the detection area can be scanned by the optical signal through the rotation of the polygon mirror. For this purpose, the mirror surfaces of the polygon mirror can be moved, for example, stepwise, with the movement being synchronized with transmitted pulses of the optical signal. The optical signal can thus move stepwise across the detection area, and by evaluating the transmitted and received optical signals, information about the points where the optical signal was reflected can be determined. The information about the reflection points includes, for example, positional information in space.
[0024] By adjusting the inclination of at least one mirror surface relative to the axis of rotation, the viewing area and thus the detection area of the lidar system can be changed in a direction perpendicular to, for example, the scanning direction by means of the oblique deflection.
[0025] In one embodiment of the lidar system, the transmit path before deflection by the first mirror surface and the receive path after deflection by the second mirror surface run on opposite sides of the polygonal mirror. This allows the lidar system to be designed even more compactly. In particular, the height required for the lidar system can be reduced, which can be advantageous, for example, for installation in the headliner behind the vehicle's windshield.
[0026] In one embodiment of the lidar system, the first mirror surface in the receive path has a different inclination relative to the axis of rotation than the second mirror surface in the transmit path. This allows the detection range of the lidar system to be increased.
[0027] The different angles of inclination of the mirror surfaces used on the transmit and receive paths can be taken into account, for example, in the receiving device when receiving the optical signals, e.g., by compensating for them. Alternatively or additionally, the different angles of inclination of the mirror surfaces used on the transmit and receive paths can be taken into account when evaluating the transmitted and received optical signals.
[0028] During a scanning process, the optical signal travels along the transmit path and the receive path. On the transmit path, the optical signal is deflected at the first mirror surface, and on the receive path, the optical signal is deflected at the second mirror surface.
[0029] In a preferred embodiment, the polygon mirror has at least four mirror surfaces, each pair of which has the same inclination to the axis of rotation. The respective pairs of mirror surfaces thus have the same angles to the axis of rotation. During operation of the lidar system, optical signals can then be transmitted and received at the same angle of inclination via a pair of mirror surfaces during each scanning process.
[0030] In one embodiment of the lidar system, the first and second mirror surfaces are arranged on adjacent sides. The optical signal is deflected during the scanning process by the first and second mirror surfaces. The polygonal mirror is thus positioned between the transmitting and receiving units such that the optical signal on the transmitting path is deflected by the first mirror surface, and the optical signal on the receiving path is deflected by the second mirror surface on the adjacent side. This embodiment allows the lidar system to be adapted to the available installation space while simultaneously enabling environmental sensing with a large field of view.
[0031] In one embodiment of the lidar system, more than two of the side faces have a mirror surface, and the deflection of the optical signal during each scanning operation is achieved by two mirror surfaces on adjacent side faces. Optionally, all side faces of the polygon mirror can have a mirror surface. Optionally, in this embodiment, the polygon mirror performs a rotational movement with complete revolutions, during which the direction of rotation is maintained. In such a 2023PF01560 6
[0032] For example, all mirror surfaces can be used successively for deflection during a complete rotational movement, with two surfaces on adjacent side surfaces being used for each scanning operation.
[0033] The mirror surfaces can be attached, in particular, as flat surfaces on the side surfaces, and in particular as flat surfaces on flat side surfaces. Flat mirror surfaces offer a constant direction of deflection across their surface.
[0034] In one embodiment of the lidar system, at least two mirror surfaces on adjacent sides are inclined at the same angle relative to the axis of rotation. During the associated scanning process, in which the at least two mirror surfaces are used, the optical signals on the transmit path can then be emitted at the same angle of inclination as they are received on the receive path.
[0035] In some embodiments of the lidar system, at least one of the mirror surfaces is parallel to the axis of rotation and / or at least two of the mirror surfaces have different inclinations relative to the axis of rotation. These embodiments each allow for precise adjustments to the size and shape of the detection area.
[0036] In embodiments of the lidar system, the respective polygons of the two base surfaces have the same number of vertices. The respective polygons can be approximately equal if the inclination of at least one mirror surface is small compared to the extent of the base surface. In particular, the two polygons of the base surface can be congruent or approximately congruent. The number of side faces and the number of possible mirror surfaces then corresponds to the number of vertices. With an odd number of vertices, for example, mirror surfaces on adjacent side faces can be used in pairs, whereby the pairwise assignment can change depending on the angular position of the rotation.
[0037] In one embodiment of the lidar system, the respective polygons are even-numbered and are designed in particular as rectangles, especially squares.
[0038] In one embodiment of the lidar system, in which the base surfaces are designed as rectangles or squares, at least two opposing 2023PF01560 7
[0039] Mirror surfaces parallel to each other. Optionally, the opposing mirror surfaces can be arranged in pairs parallel to each other. In such an embodiment, the opposing mirror surfaces can then be used optionally in the same scanning process or optionally in different scanning processes. This makes the possibilities for adapting the shape and size of the detection area even more precise and versatile.
[0040] In embodiments of the lidar system, at least two opposing mirror surfaces are inclined at the same angle relative to the axis of rotation. Optionally, the respective opposing mirror surfaces can be inclined in pairs at the same angle relative to the axis of rotation. In such embodiments, the opposing mirror surfaces can then optionally be used in the same scanning process or optionally in different scanning processes. This makes the possibilities for adapting the shape and size of the detection area even more precise and versatile.
[0041] In embodiments of the lidar system, the first and second mirror surfaces used for each scanning movement are arranged on opposite sides. The deflection of the optical signal during a scanning operation is achieved by the first mirror surface on the transmit path and the second mirror surface on the receive path. During each scanning operation, the optical signals on the transmit path can then be emitted at the same angle of inclination as they are received on the receive path.
[0042] In embodiments of the lidar system, the polygon mirror has a base body. This base body is essentially in the shape of a prism with the base and side faces of the polygon mirror. The base body has at least one recess in at least one of its base faces. This recess is designed and positioned such that the center of mass of the base body falls at least approximately on the axis of rotation. This allows the polygon mirror to be balanced and prevents imbalance. The rotational movement of the polygon mirror can thus be made smoother.
[0043] A vehicle is equipped with the described lidar system. The detection range of the lidar system installed in the vehicle is located in the vicinity of the vehicle and can be used, for example, to monitor a short or long area. 2023PF01560 8
[0044] The lidar system can be used in the front, rear, or blind spot areas of the vehicle. In conjunction with the vehicle, it can be used to monitor the vehicle's surroundings, such as the road surface, for objects, and is particularly useful for autonomous or semi-autonomous driving functions.
[0045] A lidar system has a polygon mirror which has side surfaces and two opposite base surfaces each designed as a polygon, wherein the polygon mirror can be rotated about an axis of rotation passing through the base surfaces.
[0046] A method for environmental sensing using the lidar system (10) exhibits:
[0047] • Emitting the optical signal,
[0048] • Deflection of the optical signal by means of a first mirror surface arranged on a first of the side surfaces along a transmission path to a detection area,
[0049] • Deflection of the optical signal by means of a second mirror surface arranged on a second of the side surfaces onto a receiving path from the detection area,
[0050] • Receiving the optical signal,
[0051] • wherein at least one of the mirror surfaces is inclined to the axis of rotation. The inclination allows the detection range to be specifically changed and, in particular, enlarged.
[0052] In one embodiment of the method, at least one parameter of the emitted optical signal is adjusted depending on the inclination of the first and / or second mirror surface. By adjusting the at least one parameter of the emitted optical signal via the transmitting device, the emitted optical signal can be adapted to the inclination of the at least one mirror surface and / or the optical signal can be adjusted to the detection range altered by the inclination.
[0053] In one embodiment of the method, at least one receiving parameter is adjusted during the reception of the optical signal depending on the inclination of the first and / or second mirror surface. By adjusting the at least one parameter of the received optical signal via the receiving device 2023PF01560 9
[0054] The received optical signal can be adjusted to the inclination of at least one mirror surface, and the optical signal can be set to the detection range altered by the inclination. In particular, pixels of a receiving sensor in the receiving device can be adjusted to the inclination. Such an adjustment also allows optical signals to be received and evaluated that are deflected at a different inclination in the transmit path than in the receive path.
[0055] List of fiories
[0056] The following section provides further explanation and description of exemplary implementations of this application with reference to the figures. They show
[0057] Fig. 1 shows a schematic representation of a vehicle with a lidar system.
[0058] Fig. 2 is a top view of the lidar system with polygon mirror, Fig. 3 is an exploded view of the lidar system from Fig. 2,
[0059] Fig. 4 shows a schematic representation of a first embodiment of the polygon mirror,
[0060] Fig. 5 Sections through the first embodiment of the polygon mirror, Fig. 6 a schematic representation of a scanning process,
[0061] Fig. 7 shows a schematic representation of two scanning processes, Figs. 8 and 9 show a schematic representation of optical paths for the first embodiment of the polygon mirror.
[0062] Fig. 10 Sections through a second embodiment of the polygon mirror, Fig. 11 a schematic representation of four scanning processes, Fig. 12 a schematic representation of optical paths for the second embodiment of the polygon mirror,
[0063] Fig. 13 shows a schematic representation of a third embodiment of the polygon mirror,
[0064] Fig. 14 schematic representations of a fourth embodiment of the polygon mirror, 2023PF01560 10
[0065] Fig. 15 shows a schematic representation of two groups of light elements of a light source,
[0066] Fig. 16 shows a schematic representation of exemplary intensity distributions of optical signals versus their divergence; Fig. 17 shows a schematic representation of a fourth embodiment of the polygon mirror.
[0067] Fig. 18 shows a schematic representation of the fourth embodiment of the polygon mirror with cutouts.
[0068] The same reference symbols are used in the figures for identical or similar elements. Representations in the figures may not be to scale.
[0069] Figure description
[0070] Figure 1 schematically shows a vehicle 20, for example a passenger car. The vehicle 20 has a lidar system 10. The lidar system 10 is arranged in a front area of the vehicle 20, and a detection area 22 is located in front of the vehicle 20 in the direction of travel. The lidar system 10 can be arranged, for example, in the area of the bumper or in the upper area of a windshield inside the vehicle 20.
[0071] The lidar system 10 comprises an optical transmitter 12, an optical receiver 14, a polygon mirror 16 as an optical deflection device, and a computing unit 18. The computing unit 18 can include a processor, an FPGA, or similar for processing data, as well as memory and data input and output interfaces.
[0072] The optical transmitter 12 emits an optical signal L. It has a light source for emitting, for example, laser light. The optical signal L is transmitted along an optical path to the detection area 22. The optical path from the transmitter 12 to the detection area 22 is also referred to as the transmission path 31. The optical receiver 14 receives the optical signal L reflected at a reflection point in the detection area 22 along the optical path. The reflection can occur, for example, at an object O located in the detection area 22. The optical path from the detection area 22 to the receiver 14 is also referred to as the reception path 33.
[0073] Optionally, the optical transmitter 12 can transmit the optical signal L in pulses. The pulsed optical signal L has short periods during which the optical signal L is transmitted. This can be referred to as a pulse. Between the pulses, the optical transmitter 12 does not transmit any optical signal L.
[0074] The polygon mirror 16 has at least two rotatable mirror surfaces SI, S2, S3, S4. The polygon mirror 16 is designed and arranged such that, on the transmission path 31, it deflects the optical signal L transmitted by the optical transmitter 12 into the detection area 22 by means of a first mirror surface SI, S2, S3, S4, and deflects the optical signal L reflected from the detection area 22 by means of a second mirror surface SI, S2, S3, S4 onto the reception path 33. The polygon mirror 16 can be controlled by the processing unit 18 such that it can assume several different angular positions and the optical signal L can traverse the detection area 22 accordingly. The optical signal L on the reception path 31 can be deflected successively by the polygon mirror 16 at different angular positions such that the optical signal L performs a scanning movement 26 over the detection area 22.
[0075] The mirror surfaces SI, S2, S3, S4 of the polygon mirror 16 can deflect the optical signal L through rotation such that the scanning movement 26 is performed by the optical signal L. During the rotation, the angular position of the polygon mirror 16 is changed. The optical signal L can be emitted in pulsed light pulses. Through scanning, information about reflection points with different solid angles relative to the lidar system 10 can be obtained.
[0076] The optical receiving device 14 comprises an optoelectronic receiving sensor, also called a detector. The receiving sensor can, for example, have point-shaped sensors, so-called pixels or receiving pixels, which can be arranged in rows or areas. A pixel can, for example, have one or more avalanche photodiodes (APDs) or one or more single-photon avalanche diodes (SPADs). With the optoelectronic detector, light, in particular the optical signal L, can be received and converted into electrical receiving signals. The electrical receiving signals can be processed by the processing unit 18. 2023PF01560 12
[0077] The processing unit 18 is configured to control the transmission of the optical signal L. Parameters of the transmitted optical signal L can be set. The transmission process can be controlled, in particular, depending on the polygon mirror 16, specifically its angular position and other properties. Specifically, the transmission process can be controlled depending on the mirror surface SI, S2, S3, S4 used on the transmit path 31 and / or the receive path 33.
[0078] The processing unit 18 is further developed to control the reception process of the optical signal L in the receiving device 14. Parameters of the detector can be adjusted. For example, pixels of the receiving sensor can be activated or deactivated and / or their sensitivity and / or spatial reception direction can be set. The reception process can be controlled, in particular, depending on the polygon mirror 16, especially its angular position and other properties. Specifically, the reception process can be controlled depending on the mirror surface SI, S2, S3, S4 used on the transmit path 31 and / or the receive path 33.
[0079] The processing unit 18 is further developed to evaluate the transmitted and received optical signal L. Environmental information about the surroundings of the vehicle 20 within the detection range 22 can be obtained from the evaluation of the optical signal L. The lidar system can output this environmental information via an interface.
[0080] A point cloud can be generated from the environmental information produced by the lidar system 10 during the evaluation process. Information is provided for each point in the point cloud, depending on the environmental information. In particular, the points in the point cloud contain information about the spatial location and distance of the reflection points within the detection area 22. The reflection points are those points within the detection area 22 where the reflection of the optical signal L emitted and received by the lidar system 10 occurred.
[0081] The point cloud can be used, for example, to detect objects O within the detection area 22, to determine the distance to such objects O, and / or to perform further analyses. The point cloud can be used, for example, in the Lidar-2023PF01560 13
[0082] System 10 can be generated from environmental information and / or the point cloud can be generated, for example, in another control unit of the vehicle 20 from the environmental information of the lidar system 10.
[0083] The additional control unit can, for example, be configured as the central vehicle computer of vehicle 20, in which data from several sensor systems of vehicle 20 can be received, evaluated, and / or further processed. The additional control unit can, for example, be used to implement autonomous or semi-autonomous driving functions.
[0084] The lidar system 10 can, for example, be mounted or integrated at the front of the vehicle 20. Lidar systems 10 are also possible for other parts of the vehicle 20, e.g., for surround-view functions, such as on the sides and / or rear of the vehicle 20. It is also possible to arrange lidar systems 10 and / or other sensor systems such as radar, ultrasound, etc., on the vehicle 20, particularly in corner areas of the vehicle 20.
[0085] The lidar system 10 can be used to detect stationary or moving objects O in the environment 22. Such objects O can include things such as vehicles, people, animals, plants, obstacles, road surface irregularities, in particular potholes or stones, lane boundaries, traffic signs, open areas, in particular parking lots, precipitation, or the like. Figure 2 schematically shows a top view of the lidar system 10 with the transmitter 12, receiver 14, and the polygon mirror 16. The transmitter 12 and the receiver 14 are arranged opposite each other on opposite sides of the polygon mirror 16.
[0086] The polygon mirror 16 has four mirror surfaces SI, S2, S3, and S4. The polygon mirror 16 is rotatable about an axis of rotation A in a direction of rotation 28. The rotation can be effected, for example, by a motor 24. The rotational movement of the polygon mirror 16 can be influenced, in particular, by the computing unit 18 by controlling the motor 24. Due to the rotational movement of the polygon mirror 16, the optical signal L, through deflection at the moving first mirror surface S1, performs a scanning movement 26 within the detection range 22.
[0087] The optical path of the optical signal L between the transmitting device 12 and the receiving device 14 has, in the angular position shown, the Polygo-2023PF01560 14
[0088] The optical path on the transmitting path 31 exhibits a first deflection at the first mirror surface S1. After a reflection in the detection area 22, the optical path on the receiving path 33 exhibits a second deflection at the second mirror surface S2.
[0089] Figure 3 schematically shows an exploded view of the lidar system 10 from Figure 2.
[0090] The polygonal mirror 16 has a base body, which can, for example, be in the shape of a prism. The prism has a rectangle, in particular a square, as its base and top face. The axis of rotation A can penetrate the base and the top face, in particular perpendicularly. The mirror surfaces SI, S2, S3, S4 can be arranged on the lateral faces of the prism. At least one of the mirror surfaces SI, S2, S3, S4 is inclined relative to the axis of rotation A.
[0091] The scanning movement 26 can, for example, be performed in a horizontal direction relative to the vehicle 20. A rotation axis A of the polygon mirror 16 can then extend vertically relative to the vehicle 20. By tilting at least one of the mirror surfaces SI, S2, S3, S4, the field of view, i.e., the detection range 22, of the lidar system 10 can be changed, in particular extended, in the vertical direction. By tilting at least one of the mirror surfaces SI, S2, S3, S4, the detection range 22 can be fanned out in the vertical direction.
[0092] The rotational movement in the direction of rotation 28 of the polygon mirror 16 is driven by a motor 24, which can be arranged below the polygon mirror 16, e.g., at the base of the prism. The motor 24 can also be arranged above the polygon mirror 16, e.g., at the top of the prism. Figure 4 shows a schematic representation of a first embodiment of the polygon mirror 16. In this embodiment, the base body of the polygon mirror 16 has the shape of an oblique prism with two identical squares as bases. The axis of rotation A runs perpendicularly through the two bases. The mirror surfaces SI, S2, which are arranged on adjacent side faces, point upwards and would deflect incident light upwards. The mirror surfaces S3, S4, which are arranged on adjacent side faces, point downwards and would deflect incident light downwards. 2023PF01560 15
[0093] In the example shown, the angles formed by the side faces of the base body relative to the bases are equal. This embodiment is also conceivable with different angles and with different base shapes. The bases themselves can then also be different shapes.
[0094] Figure 5 shows sections through the first embodiment of the polygonal mirror 16. The mirror surface S1 is inclined at an angle 51 relative to the base surfaces and faces upwards, thus deflecting incident light upwards. The mirror surface S2 is inclined at an angle 53 relative to the base surfaces and faces upwards, thus deflecting incident light upwards. The mirror surface S3 is inclined at an angle 55 relative to the base surfaces and faces downwards, thus deflecting incident light downwards. The mirror surface S4 is inclined at an angle 57 relative to the base surfaces and faces downwards, thus deflecting incident light downwards.
[0095] If the axis of rotation A runs perpendicular to the base surfaces, the mirror surfaces have corresponding angles relative to the axis of rotation, which correspond to the respective complementary angles of angles 51, 53, 55, 57 to 90°.
[0096] Figure 6 shows a schematic representation of a first scanning process 61, which is carried out using the first embodiment of the polygon mirror 16 from Figures 2 and 3.
[0097] In the first scanning process 61, the optical signal L is emitted from the transmitting device 12 onto the mirror surface S1 and received by the receiving device 14 from the mirror surface S2. Both mirror surfaces S1 and S2 have the same inclination relative to the axis of rotation A and both point upwards.
[0098] Figure 7 shows a schematic representation of the first scanning process 61 of Figure 6 and a second scanning process 71 in the detection area 22.
[0099] In the second scanning process 71, the optical signal L is emitted from the transmitting device 12 onto the mirror surface S3 and received by the receiving device 14 from the mirror surface S4. Both mirror surfaces S3 and S4 have the same inclination relative to the axis of rotation A and both point downwards. Accordingly, the scanning by the second scanning process 71 in the detection area 22 is offset from the first scanning process 61.2023PF01560 16
[0100] By using the first embodiment of the polygon mirror 16, the detection range 22 of the lidar system 10 can be increased. For example, the mirror surface pairs SI, S2 and S3, S4 can be used alternately during one rotation of the polygon mirror 16.
[0101] Figure 8 shows a schematic representation of the transmit path 31 and receive path 33 of the optical signal L for the first embodiment of the polygon mirror 16. The depicted transmit and receive path 31, 33 corresponds to the first scanning process 61 of Figures 6 and 7, in which the mirror surfaces S1 and S2 are used for deflection. The mirror surfaces S1 and S2 used point in the same direction (upwards in Figures 6 and 7, to the right in Figure 8).
[0102] Figure 9 shows a schematic representation of the transmit path 31 and receive path 33 of the optical signal L for the first embodiment of the polygon mirror 16. The depicted transmit and receive path 31, 33 corresponds to the second scanning process 71 of Figure 7, in which the mirror surfaces S3 and S4 are used for deflection. The mirror surfaces S3 and S4 used point in the same direction, which differs from the direction in which the mirror surfaces S1, S2 point, which are used for the first scanning process 61.
[0103] Figure 10 shows sections through a second embodiment of the polygon mirror 16.
[0104] Mirror surface S1 is inclined relative to the base surfaces and points upwards, thus deflecting incident light upwards. Mirror surface S2 is perpendicular to the base surfaces. Mirror surface S3 is inclined relative to the base surfaces and points downwards, thus deflecting incident light downwards. Mirror surface S4 is perpendicular to the base surfaces.
[0105] If the axis of rotation A is perpendicular to the bases, then the mirror surfaces S1 and S3 exhibit corresponding angles with respect to the axis of rotation, which correspond to the respective complementary angles of their angles with the bases, resulting in 90°. The mirror surfaces S2 and S4 have no inclination with respect to the axis of rotation A. They are parallel to the axis of rotation A.
[0106] Figure 11 shows a schematic representation of four scanning processes 91, 92, 93, 94 in the detection area 22 when using the second embodiment of the polygon mirror 16. Inclinations of the mirror surfaces S1, S3 of the second embodiment of the polygon mirror 16 are shown in Figure 10. 2023PF01560 17
[0107] In scanning operation 91, the optical signal L is emitted from the transmitter 12 onto the mirror surface S1 and received by the receiver 14 from the mirror surface S2. In scanning operation 92, the optical signal L is emitted from the transmitter 12 onto the mirror surface S2 and received by the receiver 14 from the mirror surface S3. In scanning operation 93, the optical signal L is emitted from the transmitter 12 onto the mirror surface S3 and received by the receiver 14 from the mirror surface S4. In scanning operation 94, the optical signal L is emitted from the transmitter 12 onto the mirror surface S4 and received by the receiver from the mirror surface S1.
[0108] The respective pairs of mirrors used each have different inclinations relative to the axis of rotation A. Accordingly, the scanning is carried out by respective scanning processes 91, 92, 93, 94 in the detection area 22 – as shown in Figure 11 – offset from each other.
[0109] By using the second embodiment of the polygon mirror 16, the detection range 22 of the lidar system 10 can be increased. For example, two adjacent mirror surfaces can be used successively in pairs during one rotation of the polygon mirror 16.
[0110] Figure 12 shows a schematic representation of transmit path 31 and receive path 33 of the optical signal L for the second embodiment of the polygon mirror 16.
[0111] The depicted transmit and receive path 31, 33 corresponds to the scanning process 91 of Figure 11, in which the mirror surface S1 in the transmit path 31 and the mirror surface S2 in the receive path 33 are used for deflection.
[0112] Figure 13 shows a schematic representation of a third embodiment of the polygon mirror 16.
[0113] In the third embodiment of the polygon mirror 16, the mirror surfaces S3 and S4 are perpendicular to the base surfaces of the base body and run parallel to the axis of rotation A. The mirror surfaces S1 and S2 are both slightly inclined relative to the axis of rotation A. The mirror surface S1 is arranged on a side surface of the base body that adjoins the side surfaces on which the mirror surfaces S4 and S2 are arranged. The mirror surface S3 is located on a side surface of the base body.
[0114] The mirror surfaces S4 and S2 are arranged on the body, adjacent to the side surfaces. Mirror surface S1 is opposite mirror surface S3. Mirror surface S2 is opposite mirror surface S4.
[0115] Figure 14 shows a schematic representation of a fourth embodiment of the polygon mirror 16.
[0116] Each of the mirror surfaces SI, S2, S3, S4 has a respective inclination with an angle al, a2, a3, a4 relative to the axis of rotation A. The angles al, a2, a3, a4 are each different from one another.
[0117] In operation of the lidar system 1, the polygon mirror 16 is arranged between the transmitting unit 12 and the receiving unit 14. Due to the rotation of the polygon mirror 16 about the axis of rotation A, the optical signal L is deflected along its optical path during a scanning operation by one of the mirror surfaces SI, S2, S3, S4 on its transmitting path 31 and by another of the mirror surfaces 51, S2, S3, S4 on its receiving path 33. The mirror surfaces SI, S2, S3, S4 are thus used in pairs for each scanning operation.
[0118] Paired use is possible, for example, by using mirror surfaces S1, S2, S3, S4, which are located on adjacent or opposite sides of the base body of the polygon mirror 16. The lower part of Figure 14 illustrates how the optical signal L is emitted onto the transmission path 31 at the corresponding different angles a1, a2, a3, a4 due to the different deflections caused by the mirror surfaces S1, S2, S3, S4.
[0119] If, for example, the optical signal L emitted by the transmitter exhibits a divergence of, say, 7° in the direction of the axis of rotation A, e.g., the vertical, this can be increased up to four times by appropriately selecting the angles a1, a2, a3, a4, e.g., up to 4 x 7° = 28°. This widening in the direction of the axis of rotation A, e.g., in the vertical, can then be achieved without having to increase the power of the light source in the transmitter 12. The transmitter can remain compact in its design and still cover a larger detection range 22. This enables a compact design of the lidar system 10.2023PF01560 19
[0120] The use of mirror surfaces SI, S2, S3, S4 in the transmit path 31 and receive path 33 can be compensated, for example, by a suitable choice of reception parameters in the receiving device 14, e.g., in the detector.
[0121] Figure 15 shows a schematic representation of the light elements of a light source of the transmitting device 12. The light source has a plurality of light elements, which are divided into a first group 151 and a second group 153. Different transmission parameters can be applied to the different groups, for example, to adapt the transmitted optical signal to the mirror surface SI, S2, S3, S4 used in the transmit path 31 and / or receive path 33. The light elements can be, for example, edge-emitting lasers (EELs) and / or vertical cavity surface-emitting lasers (VCSELs). For example, in the case of VCSELs, different voltages can be applied to the first group 151 and the second group 153 of VCSELs.This allows for the realization of different beam angles and different vertical intensity distributions, which in turn can be adjusted depending on the mirror surfaces SI, S2, S3, S4 used in the transmit path 31 and / or receive path 33. Figure 16 shows a schematic representation of exemplary intensity distributions (ordinate) of optical signals L versus their divergence (abscissa).
[0122] By applying different voltages to the light elements, e.g., VCSELs, different output angles can be achieved via the varying transmit-output divergences (abscissa). This can, for example, reduce optical artifacts such as blooming.
[0123] Figure 17 shows a schematic side view of a fourth embodiment of the polygon mirror 16. The fourth embodiment of the polygon mirror 16 has side surfaces inclined relative to the axis of rotation A, with mirror surfaces SI, S2, S3, S4. At least one of the mirror surfaces SI, S2, S3, S4 is inclined relative to the axis of rotation A.
[0124] Figure 18 shows a schematic representation of the fourth embodiment of the polygon mirror 16 with recesses 181. Mass is selectively removed at the locations of the recesses 181 to make the mass distribution of the polygon mirror 16 more uniform.
[0125] The recesses 181 are attached to the base body of the polygon mirror 16 in such a way that the mass of the polygon mirror 16 is distributed uniformly around its axis of rotation. 2023PF01560 20
[0126] The mass distribution is such that the center of gravity lies on the axis of rotation A. This allows any uneven mass distribution to be compensated for by the inclination of at least one of the mirror surfaces SI, S2, S3, S4 relative to the axis of rotation A.
[0127] This prevents vibrations and / or oscillations when rotating the polygon mirror 16. This allows the polygon mirror 16 to be rotated at high speeds. Smooth running is improved, wear and damage to bearings and other mechanical parts can be avoided, and the service life of the polygon mirror 16 can be extended. 2023PF01560 21 Bezuoszeichen
[0128] 10 Li dar- system
[0129] 12 optical transmitting device 14 optical receiving device 16 polygon mirror
[0130] SI, S2, S3, S4 Mirror surface
[0131] 18 computing units
[0132] 20 vehicles
[0133] 22 Detection area
[0134] 24 Motor
[0135] 26 scanning movement
[0136] 28 Direction of rotation
[0137] 31 Transmission path
[0138] 33 Reception path
[0139] 51, 53, 55, 57 angles
[0140] al, o2, o3, o4 angles
[0141] 61, 71 Sampling process
[0142] 91, 93, 95, 97 Sampling process
[0143] 151, 153 Group of light sources 181 Recess
[0144] A axis of rotation
[0145] L optical signal
[0146] 0 objects
Claims
2023PF01560 22 REQUIREMENTS 1. Lidar system (10) for a vehicle, wherein the lidar system (10) comprises: an optical transmitting device (12) which is configured to transmit an optical signal (L) onto a transmitting path (31), an optical receiving device (14) which is configured to receive the optical signal (L) on a receiving path (33), a polygon mirror (16) which has side faces (SI, S2, S3, S4) and two opposite base faces each designed as a polygon, wherein the polygon mirror (16) is rotatable about an axis of rotation (A) passing through the base faces, wherein a first of the side surfaces has a first mirror surface (SI, S2, S3, S4) which is configured to deflect the optical signal (L) on the transmission path (31) to a detection area (22), and wherein a second of the side surfaces has a second mirror surface (SI, S2, S3, S4) which is configured to deflect the optical signal (L) on the receiving path (33) from the detection area (22), where at least one of the mirror surfaces (SI, S2, S3, S4) is inclined to the axis of rotation (A).
2. Lidar system (10) according to claim 1, wherein the polygon mirror (16) is arranged between the transmitting device (12) and the receiving device (14) and / or the detection area (22) can be scanned by the optical signal (L) through the rotational movement of the polygon mirror (16).
3. Lidar system (10) according to claim 1 or 2, wherein the transmit path (31) before the deflection by the first mirror surface (SI, S2, S3, S4) and the receive path (33) after the deflection by the second mirror surface (SI, S2, S3, S4) run on opposite sides of the polygon mirror (16).
4. Lidar system (10) according to one of the preceding claims, wherein the first mirror surface (SI, S2, S3, S4) in the receive path has a different inclination relative to the axis of rotation (A) than the second mirror surface (SI, S2, S3, S4) in the transmit path (33). 2023PF01560 23 5. Lidar system (10) according to one of the preceding claims, wherein the polygon mirror has at least four mirror surfaces, each pair having the same inclination to the axis of rotation.
6. Lidar system (10) according to one of the preceding claims, wherein the first and second mirror surfaces (SI, S2, S3, S4) are arranged on adjacent side surfaces and the deflection of the optical signal (L) during a scanning operation (61, 71, 91, 93, 95, 97) is carried out by the first and second mirror surfaces (SI, S2, S3, S4).
7. Lidar system (10) according to one of the preceding claims, wherein more than two of the side surfaces have a respective mirror surface (SI, S2, S3, S4) and wherein the deflection of the optical signal (L) during a respective scanning operation (61, 71, 91, 93, 95, 97) is carried out by respective two mirror surfaces (SI, S2, S3, S4) on adjacent side surfaces.
8. Lidar system (10) according to one of the preceding claims, wherein at least two mirror surfaces (SI, S2, S3, S4) on adjacent side surfaces are inclined by the same angle (51, 53, 55, 57) relative to the axis of rotation (A).
9. Lidar system (10) according to one of the preceding claims, wherein at least one of the mirror surfaces (SI, S2, S3, S4) is parallel to the axis of rotation (A) and / or wherein at least two of the mirror surfaces (SI, S2, S3, S4) have different inclinations relative to the axis of rotation (A).
10. Lidar system (10) according to one of the preceding claims, wherein the polygons of the two base surfaces have the same number of vertices.
11. Lidar system (10) according to claim 10, wherein the respective polygons are even-numbered and are in particular designed as rectangles, especially squares.
12. Lidar system (10) according to claim 11, wherein at least two opposing mirror surfaces (SI, S2, S3, S4) are parallel to each other and / or wherein at least two opposing mirror surfaces are inclined by the same angle (51, 53, 55, 57) relative to the axis of rotation (A). 2023PF01560 24 13. Lidar system (10) according to one of the preceding claims, wherein the polygon mirror (16) has a base body with at least one recess (181) in at least one of the base surfaces, wherein the at least one recess (181) is designed and arranged such that the center of mass of the base body falls at least approximately on the axis of rotation (A).
14. Vehicle (20) comprising a lidar system (10) according to any of the preceding claims.
15. Method for environmental sensing using a lidar system (10), wherein the lidar system (10) has a polygon mirror (16) which has side faces and two opposite base faces each designed as a polygon, wherein the polygon mirror (16) is rotatable about an axis of rotation (A) passing through the base faces, wherein the method comprises: Emitting an optical signal (L), Deflection of the optical signal (L) by means of a first mirror surface (SI, S2, S3, S4) arranged on a first of the side surfaces on a transmission path (31) to a detection area (22), Deflection of the optical signal (L) by means of a second mirror surface (SI, S2, S3, S4) arranged on a second of the side surfaces on a receiving path (33) from the detection area (22), Receiving the optical signal (L), where at least one of the mirror surfaces (SI, S2, S3, S4) is inclined to the axis of rotation (A).
16. Method according to claim 15, wherein at least one parameter of the emitted optical signal (L) is adjusted depending on the inclination of the first and / or second mirror surface (SI, S2, S3, S4).
17. Method according to claim 15 or 16, wherein at least one receiving parameter is set when receiving the optical signal (L) depending on the inclination of the first and / or second mirror surface (SI, S2, S3, S4).