DE102010054078B4 - laser sensor for driver assistance systems - Google Patents

Abstract

Laser sensor (1) for a driver assistance system for detecting the surroundings of a vehicle, with a transmitting unit (21) and a receiving unit (41), wherein the transmitting unit (21) has a predetermined number of laser elements (28) for generating corresponding laser beams,
the laser beams form a fan-shaped arrangement in a first plane, wherein the two outer laser beams of the fan define a predetermined detection angle, adjacent laser beams of the fan are arranged at a predetermined angular distance and the laser fan is scanned in the first plane by the predetermined angular distance,
a first optical unit (22) is arranged in front of the transmitting unit (21), which generates the laser fan,
the scanning of the laser fan is generated by a movement of the transmitting unit (21) and/or by a movement of the first optical unit (22),
the transmitting unit (21) has a movable second optical unit (3) which is arranged in the beam direction after the first optical unit (22), and
a movement of the second optical unit (3) causes a displacement of the laser fan in a second plane, wherein the second plane is arranged perpendicular to the first plane.

Description

The invention relates to a laser sensor for a driver assistance system of a motor vehicle.

• - Lasersensoren mit einer Vielzahl von Sende- und Empfangskanälen (Multikanal) sowie
• - Lasersensoren mit einem nachgeführten Strahlfächer.

Laser sensors for driver assistance systems are used in today's motor vehicles, for example, to precisely determine the vehicle's surroundings in order to provide the driver assistance system with data about other vehicles or obstacles in the immediate and wider area. When installing a laser sensor above the windshield to observe the area in front of the vehicle, two laser sensor principles have previously been relevant:

• - Laser sensors with a variety of transmit and receive channels (multi-channel) and
• - Laser sensors with a tracking beam fan.

While the multi-channel concept requires a large number of expensive photo semiconductors to achieve an acceptable lateral resolution, the mechanical tracking concept achieves a good lateral resolution through its superimposed scanning movements. However, this required a mechanism that has not been particularly robust so far. In addition, there is a complex and complicated fiber optic technology that was installed to further minimize the number of photo semiconductors.

This shows the DE 199 23 702 A1 a distance sensor system for detecting objects in the surroundings of a motor vehicle with a laser scanner for monitoring a monitoring sector, wherein the laser beam of the scanner is redirected by a device for reversing the pivoting movement after sweeping over the monitoring sector.

Furthermore, DE 195 30 281 C2 a device for optically detecting obstacles in front of vehicles within a surveillance sector, which has a scanner arranged on the vehicle which moves a narrowly focused beam of light pulses in a substantially horizontal pivoting plane through 360°, wherein adjacent to the scanner in the pivoting plane and outside the surveillance sector at least one plane mirror is arranged which reflects the light beam into the surveillance sector.

From the publication DE 10 2007 004 609 A1 A vehicle-based lidar system consisting of an array of several laser diodes arranged next to one another is known, whereby each laser diode of the array can be activated in sequence. An optical element for beam shaping is arranged in front of the laser array so that interrogation beams can be generated in essentially different spatial directions, which can be controlled individually. Furthermore, the optical element can be moved relative to the laser array so that the spatial direction of the active charging beam can be changed. To detect the reflected beams, the lidar system comprises one or more photodetectors, whereby a photodetector is arranged in the vicinity of each laser element in an integrated form. Complete monitoring of an angular range is not possible.

The publication DE 102007011 804 A1 relates to a measuring arrangement comprising a radiation device which has at least a first surface-emitting semiconductor component with a vertical emission direction, a detection device for detecting reflected radiation and an evaluation circuit which is set up to control the radiation device and the detection device and to process a detection result of the detection device. The semiconductor component comprises a semiconductor body with a plurality of active regions suitable for generating radiation and arranged at a distance from one another in the vertical direction. A tunnel junction is monolithically integrated in the semiconductor body between two active regions and the two active regions are electrically connected by means of the tunnel junction during operation of the semiconductor component.

The publication US 2007/0181810 A1 describes vehicle-based LIDAR systems and methods using multiple lasers to provide more compact and cost-effective LIDAR functionality. Each laser in an array of lasers can be activated sequentially so that a corresponding optical element mounted with respect to the laser array produces corresponding interrogation beams in substantially different directions. The light from these beams is reflected from objects in the vicinity of a vehicle and detected in such a way that it provides information about the objects to vehicle operators and/or passengers.

• - eine Vielzahl von ersten optischen Elementen, die konfiguriert sind, um einen Teil eines gepulsten Laserstrahls, der von einer Lichtquelle erzeugt wird, zu einem Lichtdetektor zu leiten und den gepulsten Laserstrahl auf einen Strahlexpander zu lenken, wobei der gepulste Laserstrahl erweitert wird; und
• - mindestens ein rotationsgesteuertes zweites optisches Element zur Steuerung des erweiterten gepulsten Laserstrahls aus dem System mit einem vorgegebenen Muster, das azimutal über ein weites Feld gescannt wird, wobei
• - das mindestens eine rotationsgesteuerte zweite optische Element auch zur Aufnahme von Reflexionen des gepulsten Laserstrahls von mindestens einem Objekt entlang des vorgegebenen Musters und zur Ausrichtung auf den Laserstrahlexpander dient, so dass die Laserstrahlreflexionen fokussiert sind, und
• - die Vielzahl der ersten optischen Elemente auch dazu dienen, dass die fokussierten Laserstrahlreflexionen auf den Lichtdetektor gerichtet werden, um die Position des mindestens ein Objekts zu bestimmen.

The publication US 2003/0046025 A1 relates to an obstacle detection system with a scanning wide-range laser comprising

• - a plurality of first optical elements configured to direct a portion of a pulsed laser beam generated by a light source to a light detector and to direct the pulsed laser beam to a beam expander, thereby expanding the pulsed laser beam; and
• - at least one rotation-controlled second optical element for controlling the extended pulsed laser beam from the system with a given pattern that is scanned azimuthally over a wide field, whereby
• - the at least one rotation-controlled second optical element also serves to receive reflections of the pulsed laser beam from at least one object along the predetermined pattern and to align them with the laser beam expander so that the laser beam reflections are focused, and
• - the plurality of first optical elements also serve to direct the focused laser beam reflections onto the light detector in order to determine the position of at least one object.

The publication JP000H08114671 A relates to a distance measuring system which transmits and receives a laser beam of a laser rangefinder via a curved glass 3, comprising an optical correction system arranged between the rangefinder and the glass to cancel the refraction of the light at the glass and thus substantially maintain the original optical axis position and the state of the light beam.

The invention is therefore based on the object of creating a laser sensor for a driver assistance system which enables good lateral resolution and sensing at different levels with a simple structure.

This object is achieved by a laser sensor for a driver assistance system for measuring the surroundings of a motor vehicle with the features of claim 1. Preferred embodiments of the invention are the subject of the subclaims.

A laser sensor according to the invention for a driver assistance system for detecting the surroundings of a vehicle has a transmitting unit and a receiving unit, wherein the transmitting unit comprises a predetermined number of laser elements for generating corresponding laser beams. The laser beams form a fan-shaped arrangement in a first plane, wherein the two outer laser beams of the fan define a predetermined detection angle, adjacent laser beams of the fan are arranged at a predetermined angular distance and the laser fan is scanned in the first plane by the predetermined angular distance.

In this case, a first optical unit is arranged in front of the transmitting unit, which generates the laser fan, wherein the scanning of the laser fan is generated by a movement of the transmitting unit and/or by a movement of the first optical unit.

Furthermore, the transmitting unit has a movable second optical unit which is arranged downstream of the first optical unit in the beam direction, the movement of which causes a displacement of the laser beams in a second plane, wherein the second plane is arranged perpendicular to the first plane.

With this measure, the laser fan can completely cover the specified angular distance between two laser beams by means of a small scanning movement and is thus able to control and measure every angle of the detection angle.

Preferably, the laser elements for generating the laser beams are arranged next to one another in the form of an array.

Preferably, the movement of the first optical unit is an oscillating horizontal movement, which is caused by a first drive. More preferably, the movement of the second optical unit is a vertical movement, which is caused by a second drive. This makes it possible to achieve continuous illumination of the detection angle within the first plane. This can also be achieved in this plane through the additional movement in the second plane.

By arranging several laser diodes at defined distances, an oscillating horizontal movement with a stroke that corresponds to the distance between the laser diodes multiplies the lateral resolution determined by the number of laser diodes. The additional vertical movement can then compensate for the vehicle inclination and/or enable sensing on several levels.

In particular, each laser unit of the transmitting unit can be controlled separately. This means that the laser sensor according to the invention is scalable and can be adapted to the respective desired driver assistance tasks in different equipment variants. This is achieved by making the measurement, i.e. the sending and receiving of the signals, dependent on the respective environmental situation and/or the driver assistance function. For example, in an ACC system (Adaptive Cruise Control), only the middle beams with a higher number of measurements per stroke can be active. For the close range, all measurements with a lower number of measurements per stroke would advantageously be active. Furthermore, it is possible to check in a first pass whether objects are in the measuring range and then the objects detected in this way can be higher resolution or higher accuracy.

From near-field sensing for an emergency braking system to the combination with a video camera (LiCam), many possible applications and variations are possible.

Preferably, the first optical unit is formed by beam shaping units, the number of which corresponds to that of the laser units, wherein a beam shaping unit arranged in front of a respective laser unit produces the desired beam cross-section of the laser beam in two planes perpendicular to the beam direction. Further preferably, the beam shaping unit assigned to a respective laser unit has a rectangular cross-section and conical shape, wherein the cone tapers in the beam direction.

This allows the beam-forming unit to produce the desired beam cross-section in two planes. Furthermore, the cone can be designed in such a way that in each shift position all or at least a significant portion of the transmitted light of the corresponding laser unit is coupled into the beam-forming unit, so that overall an optimal coupling of the laser into the first optical unit acting as a beam former is achieved.

Preferably, the second optical unit is formed by a mirror, for example a concave mirror.

The receiving unit preferably further comprises an array of photodetectors, the number of which is equal to the number of laser units, with a third optical unit formed by light collector elements being arranged in front of the receiving unit, so that each photodetector is assigned a light collector element. The light collector elements preferably have a rectangular cross-section and a conical shape, with the cone tapering towards the photodetector, i.e. in the beam direction of the incident, reflected beam.

Preferably, a fourth optical unit is arranged in front of the third optical unit, which guides the reflected light of a respective laser unit to the corresponding light collector element of the photodetector corresponding to the respective laser unit. In particular, the fourth optical unit can be formed by a concave mirror, for example.

For further optimization, the exit windows of the beam-forming elements can be arranged on a correction curve to correct the imaging errors of the second optical unit. In an analogous manner, the entrance windows of the light-collecting elements can also be arranged on a corresponding correction curve to correct the imaging errors of the fourth optical unit. The correction curves result from the geometry of the second and fourth optical units, respectively.

Furthermore, it is possible to move the receiving unit synchronously with the scanning of the laser fan, thereby improving the signal-to-noise ratio of a measurement.

Furthermore, the laser sensor can have a short-range sensor, the short-range transmitting unit of which is preferably arranged below the transmitting unit formed by the laser units and the short-range receiving unit of which is preferably arranged below the receiving unit formed by the photodetectors.

• - Der Sensor ist modular aufgebaut und kann in seiner Ausgestaltung unterschiedlichen Fahrerassistenzsystemen angepasst werden. Von der einfachsten Ausführung mit festen Strahlen bis zu LiCam. Auch ein 3D-Scanner ist realisierbar.
• - Die Lateralauflösung ist skalierbar und im Grunde nur durch den Aufwand an Auswerte-Hardware und deren Verarbeitungsgeschwindigkeit begrenzt.
• - Die Scanbewegung mit ihrer geringer Amplitude ist mit einfachen mechanischen Mitteln darstellbar. Denkbare Lösungen sind Hubmagnet (siehe 6), Piezoelemente oder eine Mechatronik, wie sie für die Bildstabilisierung bei Digitalkameras angewendet wird.
• - Die Minimalmechanik und die hier eingesetzte Optik führen zu geringeren Abmessungen.
• - Durch den Aufbau mit den auf Abstand montierten Laserdioden ist genug Raum zu deren verlustfreiem und prozesssicherem Bonding vorhanden. Das ist unterschiedlich zu einem Multikanal-Aufbau, bei dem die Laserdioden auf ihrer aktiven Fläche gebondet werden müssen.
• - Die Horizontalbewegung erfolgt durch die Hubbewegungen des Lichtformers vor der Sendeeinheit. Die Elektronik ist auf einer Platine montiert. Normalerweise ist sie bei Bewegungen sehr anfällig. Aus diesem Grund ist es sehr vorteilhaft, nur die Strahlformer zu bewegen, um so die Elektronik nicht zu belasten, insbesondere die Anschlussleitungen.
• - Die Vertikalbewegung wird erreicht, indem beispielsweise der Spiegel in die entsprechende Ebene gekippt wird. Der Vorteil besteht darin, dass eine komplizierte Vertikal- und Horizontalbewegung an einem Element nicht notwendig ist.
• - Weiterhin ist es vorteilhaft, dass der Spiegel mit nur einer niedrigen Frequenz von beispielsweise 2 bis 5 Hz kontinuierlich bewegt wird, um 3 D-Informationen zu bekommen.
• - Eine Frequenz von beispielsweise 1 bis 2 Hz ist für den Spiegel ausreichend, um die Nickbewegungen des Fahrzeugs zu kompensieren.
• - Die Messfolge während der Bewegung in horizontaler Ebene ist skalierbar, d.h. bei einer ersten Messfolge zur Detektion von mindestens einem Objekt ist die Bewegung gleichmäßig. Im weiteren Messverlauf wird die Messfolge, d.h. die Anzahl der Messungen pro Zeiteinheit dort erhöht, wo zuvor ein Objekt erfasst wurde, um so bessere Messwerte zu bekommen. D.h. es werden auch nur die Messungen z.B. an drei Kanälen durchgeführt, die dem Objekt zugewandt sind. Der Vorteil ist, dass die Auswertung so nicht mit den uninteressanten Informationen außerhalb des detektierten Objektes belastet wird. Zwischendurch, beispielsweise alle 0,5 Sekunden, kann der komplette Messverlauf mit allen Kanälen durchgeführt werden, damit zwischenzeitlich im Überwachungsbereich, d.h. dem Bereich der komplett mit allen Kanälen überwacht wird bzw. überwacht werden kann, aufgetauchte Objekte erfasst werden. Wird ein neues Objekt erfasst, das aufgrund seiner näheren Entfernung eine höhere Relevanz hat, wird dieser Bereich nachfolgend mit einer höheren Messfolge untersucht.

The laser sensor according to the invention therefore has the following advantages:

• - The sensor has a modular design and can be adapted to different driver assistance systems. From the simplest version with fixed beams to LiCam. A 3D scanner is also possible.
• - The lateral resolution is scalable and basically only limited by the effort required for evaluation hardware and its processing speed.
• - The scanning movement with its low amplitude can be represented by simple mechanical means. Possible solutions are lifting magnets (see 6 ), piezo elements or mechatronics, as used for image stabilization in digital cameras.
• - The minimal mechanics and the optics used here lead to smaller dimensions.
• - The design with the laser diodes mounted at a distance provides enough space for their loss-free and process-safe bonding. This is different from a multi-channel design in which the laser diodes have to be bonded on their active surface.
• - The horizontal movement is achieved by the lifting movements of the light shaper in front of the transmitter unit. The electronics are mounted on a circuit board. Normally they are very sensitive to movements. For this reason, it is very advantageous to only move the beam shapers in order not to put any strain on the electronics, especially the connecting cables.
• - The vertical movement is achieved by tilting the mirror into the corresponding plane. The advantage is that that complicated vertical and horizontal movement on one element is not necessary.
• - Furthermore, it is advantageous that the mirror is continuously moved at only a low frequency of, for example, 2 to 5 Hz in order to obtain 3D information.
• - A frequency of, for example, 1 to 2 Hz is sufficient for the mirror to compensate for the pitching movements of the vehicle.
• - The measurement sequence during movement in a horizontal plane is scalable, i.e. in a first measurement sequence to detect at least one object, the movement is uniform. As the measurement progresses, the measurement sequence, i.e. the number of measurements per unit of time, is increased where an object was previously detected in order to obtain better measured values. This means that only the measurements on, for example, three channels that face the object are carried out. The advantage is that the evaluation is not burdened with uninteresting information outside of the detected object. In between, for example every 0.5 seconds, the complete measurement sequence can be carried out with all channels so that objects that have appeared in the meantime in the surveillance area, i.e. the area that is or can be monitored completely with all channels, can be detected. If a new object is detected that is more relevant due to its closer distance, this area is subsequently examined with a higher measurement sequence.

• 1 einen Lasersensor in schematischer Darstellung,
• 2 eine Sendeeinheit in schematischer Darstellung,
• 3 einen Querschnitt durch ein Strahlformungselement der ersten optischen Einheit,
• 4 einen Querschnitt durch mehrere Lichtsammelelemente der dritten optischen Einheit,
• 5 die Strahlgeometrie des Lasersensors in seitlicher Betrachtung,
• 6 die Strahlgeometrie des Lasersensors in Draufsicht,
• 7 den Strahlverlauf in den Lichtsammelelementen der dritten optischen Einheit unter einem ersten Winkel,
• 8 den Strahlverlauf in den Lichtsammelelementen der dritten optischen Einheit unter einem zweiten Winkel,
• 9 den Strahlverlauf in den Lichtsammelelementen der dritten optischen Einheit unter einem dritten Winkel, und
• 10 den Strahlverlauf in den Lichtsammelelementen der dritten optischen Einheit unter einem vierten Winkel.

A preferred embodiment of the invention is explained below with reference to the drawings.

• 1 a laser sensor in schematic representation,
• 2 a transmitting unit in schematic representation,
• 3 a cross-section through a beam-forming element of the first optical unit,
• 4 a cross-section through several light-collecting elements of the third optical unit,
• 5 the beam geometry of the laser sensor viewed from the side,
• 6 the beam geometry of the laser sensor in top view,
• 7 the beam path in the light-collecting elements of the third optical unit at a first angle,
• 8 the beam path in the light-collecting elements of the third optical unit at a second angle,
• 9 the beam path in the light-collecting elements of the third optical unit at a third angle, and
• 10 the beam path in the light collecting elements of the third optical unit at a fourth angle.

1 shows a preferred embodiment of the laser sensor 1 in a schematic representation. The laser sensor 1 comprises a transmitting device 2, a concave mirror 3 arranged opposite the transmitting device 2, a receiving device 4 and a further concave mirror 5 arranged opposite the receiving device. The transmitting device 2 and the receiving device 4 are arranged on a base plate 6, with all components of the laser sensor 1 being accommodated in a housing 7 shown schematically here. The concave mirror 3 arranged opposite the transmitting device 2 corresponds to the second optical unit already mentioned, since instead of a concave mirror, for example, a corresponding lens arrangement could also be used. Likewise, the further concave mirror arranged opposite the receiving device 4 corresponds to the fourth optical unit. Instead of the further concave mirror 5, the fourth optical unit could also be replaced by a lens system.

Furthermore, in 1 schematically shown that a near-field transmitting unit 27 is arranged below the transmitting device 2 and a near-field receiving unit is arranged below the receiving device 4.

2 shows the transmitter 2 of the 1 in greater detail. The transmitting device 2 comprises a transmitting unit 21, which in the present example consists of seven laser diodes (not shown) arranged in a row on a carrier board, with the distances between the laser diodes corresponding to twice the beam exit width. A beam-forming unit 22 acting as the first optical unit is arranged in front of the transmitting unit 21, with each laser diode being assigned a beam-forming element 221, ..., 227 acting as a light guide. The beam-forming unit 22 oscillates, for example, at around 40 Hz and a stroke of around 2.4 mm in the direction of movement 26 shown schematically as an arrow. This oscillation is caused by a movement device 23, which transmits the movement via an axis 24 to a holder 25 of the beam-forming unit 22. The holder 25 serves to arrange the beam-forming elements 221 to 227.

Furthermore, the 2 a near-field transmission unit 27 is shown and is arranged below the beam forming unit 22. The near-field transmission unit 27 can be implemented with conventional LEDs and detects detection gaps in front of the motor vehicle.

3 shows one of the beam-forming elements 221 of the beam-forming unit 22 together with a laser diode 28 in a schematic longitudinal section. The light from the laser diode 28 is coupled into the beam-forming element 221 via an entrance window 22E and leaves the beam-forming element 221 via a corresponding exit window 22A. In the preferred embodiment, the beam-forming element has a rectangular cross-section and tapers from the entrance window 22E to the exit window 22A, in other words, the beam-forming element 221 has a conical shape in the laser light direction 29. The rectangular cross-section is only to be understood as an example; other suitable cross-sectional shapes, for example circular, are also possible.

By the lifting movement of the movement device 23 of the 2 In the example, the seven laser beams formed by the beam forming unit 22 are shifted in a horizontal direction, whereby the single beam formed in this way is reflected via the concave mirror 3 of the 1 to a horizontal divergence of approximately 1.25° and a vertical divergence of approximately 4°. An object, for example a surface facing the laser sensor 1, is thus illuminated with a row of seven laser light spots that oscillate horizontally so that no gaps remain.

In order to compensate for pitching movements of the vehicle or to obtain a three-dimensional image of the surroundings, the 1 Concave mirror 3, ie the second optical unit, can be tilted into the corresponding plane, for example by rotation about a horizontal axis (not shown), whereby a deflection of the laser beams in a vertical direction is achieved. The concave mirror 3 can be moved continuously at a frequency of 2 to 5 Hz in order to obtain a three-dimensional image. A frequency of 1 to 2 Hz is sufficient to compensate for pitching movements of the vehicle.

To compensate for the spherical aberration of the concave mirror 3, the exit windows 22A of the beam shaping elements 221 to 227 of the beam shaping unit 2 of the 2 arranged on a correction curve, for example a circular path.

4 shows the 1 shown receiving device 4 consisting of a receiving unit 41 and a light collecting unit 42. The receiving unit 41 has in the example seven photodetectors 411 to 417, which corresponds to the number of laser beams of the transmitting unit 21 in 2 The light collecting unit 41 arranged in front of the receiving unit 41 comprises a corresponding number of seven light collecting elements 421 to 427, which preferably have a rectangular cross-section and which have a conical shape from the respective light entry surface 42E to the light exit surface 42A in order to collect the light from the concave mirror 5 of the 1 to optimally collect the light directed to the light collection unit across the oscillation range of the laser beams and to feed it to the photodiodes 411 to 417.

5 shows a motor vehicle 8 which is equipped with a laser sensor (not shown) on the upper edge of the windshield. The laser sensor has a long-range area 9 which covers a vertical angle range of 4°. Below the long-range area 9 is the close-range area 10 which covers a range of 10° in the vertical direction. The long-range area 9 and the close-range area are separated by an area of approximately 1°. This area of 1° corresponds to the pitch range of the motor vehicle 8.

6 shows the beam geometry of the laser sensor of a motor vehicle 8 on a three-lane highway 11 in a top view. The long-range area 9 can be seen with a coverage area in the horizontal direction of, for example, 32.1°. The detection range is approximately 150m, with each beam in the preferred embodiment having a width of 1.24° and a scanning range of 4.58°. In contrast, the short-range area 10 has a range of max. 15m and a coverage width in the horizontal direction of approximately 50°.

7 shows the beam path in the light collection unit 42 for an angle of incidence of 0° on the concave mirror 5. Due to the arrangement of the entrance surfaces 42E of the light collection elements 421 to 427 on a correction curve for correcting the spherical aberration of the concave mirror 5, all light of this angle is supplied by the middle light collection element 424, whereby this angle corresponds in the assignment to the light of the middle laser element of the transmission unit 21.

8 corresponds to a beam path at an angle of incidence of 4.6°, whereby this light is supplied by the light collecting element 425.

9 corresponds to a beam path at an angle of incidence of 9.1°, whereby this light is supplied by the light collecting element 426.

10 corresponds to a beam path at an angle of incidence of 13.5°, whereby this light is supplied by the light collecting element 427.

The light collecting elements 421 to 423 correspond to the negative angles of incidence -4.6°, -9.1° and -13.5° and are not shown separately.

list of reference symbols

1

laser sensor

2

transmitting device with transmitting unit and first optical unit

3

concave mirror (second optical unit)

4

Receiving device with receiving unit and third optical unit

5

concave mirror (fourth optical unit)

6

base plate

7

Housing

8

motor vehicle

9

long-distance range

10

close range

11

Highway

21

transmitter unit

22

first optical unit

221

beam-forming element

222

beam-forming element

223

beam-forming element

224

beam-forming element

225

beam-forming element

226

beam-forming element

227

beam-forming element

23

lifting element

24

axis

25

beam-forming element holder

26

direction of movement

27

near-field transmitter unit

28

laser diode

22E

entrance area

22A

exit surface

29

laser light direction

41

receiving unit

411

photodetector

412

photodetector

413

photodetector

414

photodetector

415

photodetector

416

photodetector

417

photodetector

42

light-collecting unit (third optical unit)

421

light-collecting element

422

light-collecting element

423

light-collecting element

424

light-collecting element

425

light-collecting element

426

light-collecting element

427

light-collecting element

42A

exit surface

42E

entrance area

43

near-field receiver unit

Claims (18)

Laser sensor (1) for a driver assistance system for detecting the surroundings of a vehicle with a transmitting unit (21) and a receiving unit (41), wherein the transmitting unit (21) has a predetermined number of laser elements (28) for generating corresponding laser beams, the laser beams form a fan-shaped arrangement in a first plane, wherein the two outer laser beams of the fan define a predetermined detection angle, adjacent laser beams of the fan are arranged at a predetermined angular distance and scanning of the laser fan takes place in the first plane by the predetermined angular distance, a first optical unit (22) is arranged in front of the transmitting unit (21), which generates the laser fan, the scanning of the laser fan is generated by a movement of the transmitting unit (21) and/or by a movement of the first optical unit (22), the transmitting unit (21) has a movable second optical unit (3) which is arranged after the first optical unit (22) in the beam direction, and a movement of the second optical unit (3) Displacement of the laser fan in a second plane, wherein the second plane is arranged perpendicular to the first plane. Laser sensor (1) after claim 1 , characterized in that the laser elements (28) are arranged next to one another in the form of an array. Laser sensor (1) according to one of the Claims 1 or 2 , characterized in that the first optical unit (22) is formed by beam-shaping elements (221, ..., 227), the number of which corresponds to that of the laser elements (28). Laser sensor (1) after claim 3 , characterized in that each beam shaping element (221, ..., 227) produces the desired beam cross-section of the laser beam in two planes perpendicular to the beam direction and is arranged in front of a respective laser element (28) Laser sensor (1) after claim 4 , characterized in that each beam-forming element (221, ..., 227) has a rectangular cross-section and a conical shape, the cone tapering in the beam direction. Laser sensor (1) according to one of the Claims 1 until 5 , characterized in that the movement of the first optical unit (22) is an oscillating horizontal movement which is caused by a first drive (23). Laser sensor (1) after claim 6 , characterized in that the movement of the second optical unit (3) is a vertical movement which is caused by a second drive. Laser sensor (1) according to one of the Claims 1 until 7 , characterized in that the second optical unit (3) is formed by a mirror. Laser sensor (1) according to one of the preceding claims, characterized in that each laser element (28) can be controlled separately. Laser sensor (1) according to one of the preceding claims, characterized in that the receiving unit (41) comprises an array of photodetectors (411, ..., 417), the number of which is equal to the number of laser units, wherein a third optical unit (42) formed by light collector elements (421, ..., 427) is arranged in front of the receiving unit (41), so that each photodetector (411, ..., 417) is assigned a light collector element (421, ..., 427). Laser sensor (1) after claim 10 , characterized in that a light collector element (421, ..., 427) has a rectangular cross-section and a conical shape, wherein the cone tapers towards the photodetector (411, ..., 417). Laser sensor (1) according to one of the Claims 10 or 11 , characterized in that a fourth optical unit (5) is arranged in front of the third optical unit (42), which guides the reflected light of a respective laser element (28) to the corresponding light collector element (421, ..., 427) of the photodetector (411, ..., 417) corresponding to the respective laser element (28). Laser sensor (1) after claim 12 , characterized in that the fourth optical unit (5) is formed by a concave mirror. Laser sensor (1) according to one of the Claims 5 until 13 , characterized in that for correcting the imaging errors of the second optical unit (22), the exit windows (22A) of the beam-forming elements (221, ... 227) are arranged on a correction curve. Laser sensor (1) according to one of the Claims 12 until 14 , characterized in that for correcting the imaging errors of the fourth optical unit (5), the entrance windows (42E) of the light collecting elements (421, ..., 427) are arranged on a correction curve. Laser sensor (1) according to one of the preceding claims, characterized in that the receiving unit (41) is moved synchronously with the scanning of the laser fan. Laser sensor (1) according to one of the preceding claims, characterized in that the laser sensor (1) has a short-range transmission unit (27) which is arranged below the transmission device (2). Laser sensor (1) after claim 17 , characterized in that the laser sensor (1) has a short-range receiving unit (43) which is arranged below the receiving device (2).

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