DE102024128423A1 - Lidar device and method for operating a lidar device - Google Patents

Abstract

The present invention relates to a lidar device for detecting the environment of a vehicle (10), wherein the lidar device comprises: at least one laser (24) provided for emitting laser light, at least one optical head (12) for emitting the laser light into the environment and for receiving laser light reflected from the environment, and at least one detector provided for converting received laser light into electrical signals.
According to the invention, a lidar central unit (14) is provided in which the at least one laser (24) and the at least one detector are arranged.
Optical fiber connections (70, 72) are arranged between the optical heads (24) and the lidar central unit, which are designed to guide emitted laser light from the at least one laser (24) to the optical heads (12) and/or received laser light from the optical heads (12) to the at least one detector.

Description

The present invention relates to a lidar device according to the preamble of claim 1, and to a method for operating a lidar device according to claim 12.

A lidar device of this type is used to detect the surroundings of a vehicle. Known lidar devices emit pulsed or continuous laser beams and receive laser light reflected from the environment, which is then converted into electrical signals by a detector. In the time-of-flight measurement method, the distance between the lidar device and an object in the environment is calculated from the travel time of light pulses. When using quasi-continuous frequency-modulated light, the distance is determined by measuring frequency differences. Detected reflection points are compiled into a lidar point cloud, which is stored as a representation of the environment and is continuously updated by a cyclical scanning process of the lidar device.

A lidar device of this type therefore comprises at least one laser designed to emit laser light. A lidar device of this type further comprises at least one optical head for emitting laser light into the environment and for receiving laser light reflected from the environment, as well as at least one detector designed to convert received laser light into electrical signals.

In known lidar devices, both the laser and the detector are integrated into the optical head. These optical heads typically have a two-dimensional scanning capability, allowing scanning in both horizontal and vertical directions. When more than one optical head is used, their installation positions are usually chosen so that their coverage areas essentially complement each other, achieving as close to 360° coverage around the vehicle as possible.

The size of known optical heads for lidar devices is comparatively large, as the laser, detector, and scanning unit must be accommodated. The necessary electronics are also housed within the optical head. Such a known optical head generates a relatively large amount of waste heat due to these components. Typically, this amounts to 20 to 30 watts of heat output. This results in a significant increase in the temperature of the installation space. However, such an optical head can only operate up to a maximum temperature, which cannot be raised arbitrarily. This maximum operating temperature depends on the temperature-dependent efficiency of the laser, the temperature-dependent noise of the detectors, and the maximum permissible operating temperatures of the installed semiconductor components. These factors limit the available installation positions and necessitate sophisticated thermal management of the installation space and the components.

In known systems, data preprocessing is also integrated into the lidar head, and the generated data volumes can exceed the capacity of existing data lines. Electrical data lines therefore represent a limiting factor and require elaborate shielding measures.

It is therefore the object of the present invention to provide a lidar device and a method for operating a lidar device in which these problems are solved.

This problem is solved by a lidar device according to the characterizing feature of claim 1 and by a method for operating a lidar device according to claim 12.

In a lidar device according to the invention as defined in claim 1, a lidar central unit is provided in which the at least one laser and the at least one detector are arranged.

The lidar device has one or more optical heads and optical fiber connections are arranged between the optical heads and the lidar central unit, which are designed to guide emitted laser light from the at least one laser to the optical heads and/or received laser light from the optical heads to the at least one detector.

Such an optical fiber connection, also called a fiber optic cable, is a light guide that can transmit light in one or, more commonly, several optical fibers. These optical fiber connections are designed to guide laser light emitted by the laser to the optical head and/or received laser light from the optical head to the detector. A corresponding fiber optic connection will therefore guide laser light either in one direction or in both directions. Along the paths of the laser light between the laser and the optical head and between the optical head and the detector—particularly within the lidar central processing unit—additional light-guiding elements may be incorporated, meaning that a fiber optic connection does not necessarily run directly from the laser in one piece. must be guided into the optical head or from the optical head to the detector.

Such a lidar device of this type offers a variety of advantages. Firstly, the optical heads of the lidar device are radically miniaturized in terms of the installation space required for vehicle integration, since the light source (laser) and the detector are no longer housed within the optical head itself. These components are integrated into the lidar central unit. In addition to the reduction in installation space, numerous heat sources are also relocated away from the optical head. These heat sources include, in particular, the laser light source, the driver circuits for operating the laser and detector, and circuits for preprocessing the electrical data derived from the reflected laser light.

A beam deflection unit or scanner can still be installed in the optical head, but the necessary electronics for controlling such a beam deflection unit can also be moved to the lidar central unit.

Since the useful signals are transmitted optically between the optical head and the lidar central unit, the requirements for EMC (Electromagnetic Compatibility) shielding are reduced: Such shielding is not relevant for the optical signal transmission component, but only for the remaining electronic lines. These are no longer high-speed data transmission lines requiring special shielding, but rather ordinary data lines, e.g., for controlling the beam deflection unit. Therefore, fewer high-speed data connections are needed for transmitting high-frequency electrical data. In contrast to the use of high-speed data connections, there is also practically no upper limit to the length of the fiber optic connection used in a lidar device according to the invention.

In a method according to the invention for operating a lidar device, laser light is emitted by one or more lasers of a lidar central unit. The emitted laser light is supplied via fiber optic connections to one or more optical heads and emitted by these into an environment. Laser light reflected from the environment is received by the optical head(s) and supplied to the lidar central unit via the same or further fiber optic connections and converted into electrical signals by at least one detector of the lidar central unit. Laser light emitted by an optical head into the environment and reflected by it is received by the same optical head and/or by one or more other optical heads.

In a method according to the invention, redundancies arise in addition to the advantages already mentioned, for example, if a particular optical head is covered by contamination to such an extent that it may still emit laser light, but can no longer usably receive the significantly weaker intensity of reflected laser light. The redundancy is thus provided by the fact that reflected light from an object to be detected, which was illuminated by one of the optical heads, can be received by several optical heads.

Preferred embodiments of the present invention are set forth in the dependent claims.

In a first preferred embodiment of the present invention, each optical head has a scanning device for spatially scanning the environment. The scanning device can include optical phase shifters, so-called Optical Phased Arrays (OPAs), which can be controlled by the lidar central unit. This offers several advantages. Known lidar devices have laser scanners that are based on mechanical beam deflection with movable optical components, such as rotating mirrors or tiltable micromirrors integrated on a chip. Phased-array antennas are known from the radar field. The necessary elements for controlling the phases of the individual antennas, such as phase shifters, can also be implemented in so-called photonic circuits. This offers the advantage that non-mechanical beam steering is possible, with all components integrated on a single chip. Optical phased arrays with components such as lasers, waveguides, beam splitters, diffraction gratings, phase shifters, and amplitude controllers, manufactured using common chip manufacturing processes, have already been demonstrated. Optical phase shifters can be realized, for example, by utilizing thermo-optical properties, whereby the refractive index of waveguides can be manipulated by means of microscopic electrical heating elements, thus causing phase shifts due to the changed optical path length between different emitters.

The installation space required by an optical head is reduced by using optical chips and/or optical phase shifters compared to known solutions with mechanically limited space. The limitations of swiveling mirrors or scanners are significantly reduced. Since such an optical phased array, unlike known lidar devices, does not enable 360° detection, but rather, for geometric reasons alone, can only achieve a maximum of 180°, this is not a disadvantage for the embodiments of the present invention, as several optical heads can be provided whose detection ranges complement each other.

In a further preferred embodiment of the present invention, an electrical connection is provided between the lidar central unit and the scanning device, which is configured to transmit control signals from the lidar central unit to the scanning device. Since only control signals are transmitted via the electrical connection, and not useful signals generated by a detector in the optical head, less complex shielding measures are required for these electrical connections.

Alternatively, fiber optic connections can be used for this purpose, in which case the control signals are optical in nature. If the fiber optic connections, which are primarily used to transmit emitted and reflected laser light, are also used for data transmission at the optical level, this will preferably occur in a spectral range separate from the lidar light or in a different polarization state in order to adequately separate "data light" from "lidar light." Polarization-maintaining optical fibers would be used for this purpose.

In a further preferred embodiment of the present invention, a single laser or several lasers arranged in the central unit are provided to emit laser light that can be distributed to a plurality of optical heads, wherein the number of optical heads is preferably greater than the number of lasers. The light source is therefore centralized and optionally designed modularly. This means that a single laser can be selected to be powerful enough to supply several or all optical heads with laser light simultaneously. Depending on the number of optical heads provided, which can be easily connected to the lidar central unit, for example, by means of an optical connector, each optical head can be guided at an ideal operating point by adding further lasers, given the modular design of the light source.

The optical fiber connection between an optical head and the lidar central unit can be implemented in different ways. In a first embodiment of the present invention, a first optical fiber connection is provided between each optical head and the lidar central unit, which is configured to guide emitted laser light to the optical head. A second optical fiber connection is also provided between each optical head and the lidar central unit, which is configured to guide received light from the optical head to the lidar central unit. In other words, a fiber optic connection is provided for both the forward and return transmission of the light.

Alternatively, each optical head is connected by a single optical fiber connection, designed to both guide the emitted laser light to the optical head and the laser light received from the optical head to the lidar central unit. Polarizing or other beam splitters, which can be located within the lidar central unit, can be used to separate the emitted and reflected light. This approach takes advantage of the fact that the emitted laser light is transmitted with a defined polarization, for example, linearly polarized in one plane, while the received reflected laser light exhibits different polarization states. In this configuration, polarization-maintaining optical fibers would be mandatory.

A further preferred embodiment of the present invention includes optical delay lines, often referred to as "delay lines," in the lidar central unit or between the lidar central unit and one or each of the optical heads. This offers the advantage of enabling the use of time-division multiplexing (TDM). In TDM, data is transmitted either at a fixed rate or in time intervals of variable length (asynchronous TDM). In data communication, packets from different users are sent alternately, so that each user appears to have exclusive use of the channel, albeit potentially at a lower speed depending on the network load. In the present case, TDM can be used to distribute emitted laser light from a laser to multiple optical heads in a time-staggered manner without losing information about which optical head the emitted laser light originates from. Such optical delay lines are known and are based on optical components such as fiber coils or ring-shaped structures in the form and technology of photonic chips. Appropriate photonic structures can, for example, increase the optical path length traveled by light through multiple reflections. However, the inclusion of optical delay lines also offers the fundamental possibility of controlling when an optical head emits laser light. Thus For example, it can be ensured that several optical heads emit laser light simultaneously or with a defined time offset, regardless of the length of the fiber optic connection with which they are connected to the lidar central unit.

In a further particularly preferred embodiment of the present invention, at least one or each optical head can receive laser light emitted by another or a plurality of other optical heads and reflected by the surroundings. This offers the advantage of multiplying the effective receiving aperture, which can be used both for redundancy and for increasing the signal-to-noise ratio, thereby increasing the maximum range. Furthermore, this measure improves availability, since if an optical head becomes blocked, for example by contamination, other, unblocked receivers can be used.

It is further preferably provided that at least one or each optical head includes a temperature measuring point, which is preferably configured to allow temperature-dependent adjustments of components within the optical head, preferably of an optical phased array of a scanning device. Optical phase shifters of an optical phased array can be implemented by selectively exploiting temperature or pressure dependencies of optical fibers in photonic chips. However, this can also lead to temperature changes within an optical head negatively affecting the scanning device. Therefore, providing a temperature measuring point offers the advantage that appropriate adjustments can be made.

In a further preferred embodiment of the present invention, amplitude switches are provided in the lidar central unit by means of which the intensity of emitted light supplied to and received by the optical heads and/or the optical fiber connections can be controlled. This offers the advantage that the light intensity transmitted through a fiber optic connection can be controlled as required.

In a further preferred embodiment of the present invention, the optical fiber connections are also designed for optical data transmission. This offers the advantage that the number of required electrical connections can be reduced, for example by transmitting signals for controlling the scanning device in the optical heads optically.

In a particularly preferred embodiment of a method according to the invention, a scanning method for varying the direction of the emitted and/or received laser light is used in each optical head. This allows defined detection areas for each optical head to be realized. Preferably, a one-dimensional scan is performed in a horizontal, vertical, or inclined direction. This offers the advantage that the scanning device in an optical head can be designed particularly simply, since, unlike known lidar devices, each optical head does not have to scan the environment in two dimensions. This is possible because, according to the invention, several optical heads can be provided whose detection areas complement each other and which can then, for example, acquire a 360° image of the environment. Preferably, a one-dimensional scan in a horizontal, vertical, or inclined direction is used in each case.

Preferably, different optical heads will perform different scans with differing scan directions. These different scan directions, such as horizontal, vertical, or inclined directions, can be implemented in such a way that the detection areas complement each other.

Preferably, a time-division multiplexing method is used when supplying laser light to the various optical heads and/or when evaluating detected reflected laser light.

In a particularly preferred embodiment of a method according to the invention, a heterodyne method is used to detect reflected laser light. Heterodyne detection methods are known from telecommunications and optics for the detection and analysis of signals. Waves of an unknown frequency are detected by mixing them with waves of a reference frequency. Here, the electric field of a received signal is mixed with the electric field of a local oscillator, the mixing being based on a non-linear product of the input signals such that at least a portion of the output signal is proportional to the square of the input signals. Essentially, mixing products with sum and difference frequencies are determined. The amplitude of the signal thus downmixed is larger than the amplitude of the original signal itself, so that a large amplitude of the local oscillator also results in a large "difference frequency amplitude".

In such a method according to the present invention, the environment The reflected and received optical signals are mixed with a stored portion of the laser light. Optical mixing of emitted and reflected laser light takes place on a detector. Since both components are temporally coherent (the coherence length of the laser must be sufficiently large to meet this condition), the electric fields of the light from the local oscillator and the light from the reflection interfere, so that the corresponding signal of the difference frequency of the two optical interference partners is detected at the detector. The heterodyne mixing frequencies (signal frequency plus oscillator frequency and signal frequency minus oscillator frequency) allow for improved detection because, on the one hand, a downmixing to lower frequencies occurs, and on the other hand, the comparatively high intensity of the emitting laser simplifies the detection of the lower intensity of reflected laser light through heterodyne detection. The other frequency components, such as the oscillation frequency of the two electric fields of the light beams, as well as the sum frequency, are also present, but are in a frequency range that the electronics cannot track.

The invention will be explained in more detail below using the figures as examples.

• 1: ein Fahrzeug 10 mit einer erfindungsgemäßen Lidar-Vorrichtung;
• 2: das Fahrzeug 10 der 1 in einer schematischen Ansicht von oben;
• 3: eine Ansicht von oben auf Scanlinien einer erfindungsgemäßen Lidar-Vorrichtung;
• 4: eine Seitenansicht auf Scanlinien einer erfindungsgemäßen Lidar-Vorrichtung;
• 5: ein Blockdiagramm einer erfindungsgemäßen Lidar-Zentraleinheit;
• 6: ein Blockdiagramm eines erfindungsgemäßen optischen Kopfs; und
• 7: eine schematische Ansicht der Verbindungen zwischen der Lidar-Zentraleinheit und einem optischen Kopf.

This shows:

• 1 : a vehicle 10 with a lidar device according to the invention;
• 2 : vehicle 10 of the 1 in a schematic view from above;
• 3 : a top view of scan lines of a lidar device according to the invention;
• 4 : a side view of scan lines of a lidar device according to the invention;
• 5 : a block diagram of a lidar central unit according to the invention;
• 6 : a block diagram of an optical head according to the invention; and
• 7 : a schematic view of the connections between the lidar central unit and an optical head.

1 Figure 1 shows a vehicle 10 according to the present invention. The vehicle 10 is equipped with a lidar device according to the invention, which has a plurality of optical heads 12. These optical heads 12 are arranged at mounting positions located at different vertical and horizontal positions on the vehicle 10.

In the schematic representation of the 2 The vehicle 10 is shown in a top view. The optical heads 12 are not only arranged at different heights, but also circumferentially around the vehicle 10, i.e., also at the front and rear of the vehicle 10 as well as on the sides of the vehicle. In the 1 and 2 Further shown is a lidar central unit 14, which can be located at any point within the vehicle body of the vehicle 10. At least one optical fiber connection 70 is provided between the optical heads 12 and the lidar central unit 14.

The 3 and 4 The scan lines schematically show a multitude of optical heads 12 in a top view (see 3 ) as well as in a side view (see 4 ), where each line is generated by a transmitting optical head.

Scan lines 16 and 18 of the 3 are those of adjacent optical heads 12 in a corner region of the vehicle 10. The scan lines 16 and 18 represent lines or wavefronts equidistant from the associated optical head 12. Laser light emitted by an optical head 12 is sent into the vicinity of the vehicle 10, where it can be reflected by an object in the vicinity. After reflection, reflected laser light is received again by one or more optical heads 12 and converted into electrical signals by a detector. As in the 3 and 4 The scan lines, particularly those of adjacent heads 16 and 18 as well as 20 and 22, overlap, thus overlapping their detection areas. The entire detection area can therefore completely encircle vehicle 10.

A key aspect of the present invention is the fact that the various optical heads 12 of the vehicle 10 can all emit laser light. Furthermore, all optical heads 10 can receive reflected laser light, not only that which they themselves have emitted, but also laser light that was originally emitted by another, for example, neighboring, optical head 12. Due to the overlapping detection ranges of the various optical heads 12, a detection range for the entire lidar device is achieved, extending 360° around the vehicle 10. Redundancies also arise if, for example, a particular optical head 12 is covered by contamination to such an extent that it may still be able to emit laser light, but can no longer receive the significantly weaker intensity of reflected laser light.

4 shows a diagonal alignment of the scan lines of optical heads 12 of the 1 and 2 The diagram schematically illustrates that the optical heads 12 of the lidar device do not perform two-dimensional scanning, as is the case with known lidar devices, but only one-dimensional scanning. In other words, the scanning elements in the optical heads 12 are designed to scan the vehicle's surroundings only in a line-like fashion. This simplifies the design and reduces the size of the corresponding scanning element in the optical heads 12.

In the 4 Scan lines 20 and 22 are shown, arranged at an angle to a horizontal or vertical direction. An inclination of 45° to a horizontal orientation is indicated as an example, with the optical heads 12 of the vehicle 10 being alternately aligned such that scan lines 20 and 22 from adjacent optical heads 10 are tilted 90° relative to each other. Of course, other inclinations to the horizontal are also possible.

Based on the 5 Further details relevant to the invention of the lidar device according to the present invention will be explained in more detail below. 5 The lidar central unit 14 shows 1 and 2 in its functionality as a schematic block diagram. Optical connections are shown with solid lines, electrical connections with dashed lines. It should be noted that, for the sake of simplicity, not all electrical connections are shown.

In the lidar device according to the invention, not every optical head 12 has a laser; instead, a central light source in the form of a central laser 24 is arranged within the lidar central unit 14. The laser 24 can actually be a single laser 24 with a sufficiently high light output to supply the various optical heads 12 with an adequate intensity of laser light. Alternatively, the laser 24 can also be modular, i.e., consist of scalable individual light sources, such as lasers or laser diodes.

The laser 24 is connected to a light electronics center 46 via an electrical connection (not shown). This light electronics center 46 serves, among other things, to control the laser 24.

The laser 24 is connected to a plurality of optical delay lines 26 via an optical link 25, and emitted laser light is coupled into these lines. If only one laser 24 is used, optical splitters or beam dividers can be provided between the laser 24 and the delay lines 28 to distribute the laser light to the delay lines 26. The delay lines 26 are connected to the optical heads 12 via optical links 29 and optical outputs 28 through the fiber optic connections 70.

The optical delay lines 26 are primarily used to control when an optical head 12 emits laser light. This can be used to execute a time-division multiplexing process.

A timing master and time multiplexer 36 is electrically connected to and controls the delay lines 26.

In addition to the optical outputs 28, the lidar central unit 14 also has a plurality of optical inputs 30. The number of optical outputs 28 and optical inputs 30 corresponds to the number of optical heads 12 arranged on the vehicle 10. Via the optical inputs 30, the lidar central unit 14 receives laser light through further fiber optic connections 72. This laser light was received by the optical heads 12 after reflection from an object in the vicinity of the vehicle 10. The optical inputs 30 are connected via optical links 31 to an optical detection center 34, which has one or more detectors. Reflected laser light received through the optical inputs 30 is thus converted into electrical signals.

The electrical signals are digitized by a processor 40 with integrated data processing electronics. The processor 40 enables further signal processing at a digital level and therefore includes an analog-to-digital converter (ADC). Fusion across multiple sensor modalities is also possible. Data from lidar, camera, radar, infrared, or ultrasound devices can be combined. For this purpose, the processor 40 sends data to a fusion center 42. Here, lidar point clouds are generated based on the signals. If different optical heads generate 12 separate point clouds, these can be combined here. Alternatively, if a first optical head emits 12 laser light and receives the reflected laser light along with others, a single point cloud can be generated using the fusion center 42.

The electrical signals processed in this way are routed to the outside by the processor 40 via a data interface 48 and made available, for example, to a central vehicle computer.

For the application of an FMCW (Frequency Modulated Continuous Wave) method, an optical storage ring 38 can also be provided. In such continuous wave detection, individual laser pulses are not emitted; instead, the laser 24 emits laser light continuously. While absolute distance measurements are not possible in unmodulated continuous wave operation, but only the velocities of detected objects can be determined by measuring Doppler frequencies, frequency-modulated methods offer the distance measurement capability to detected objects, which is of course essential for a lidar device. In simplified terms, the FMCW method is based on the fact that the frequency of the emitted laser light is changed over time, i.e., modulated, and the travel time of the changed frequency components is measured. In principle, any type of modulation (frequency modulation, phase modulation, and amplitude modulation) is suitable for marking the emitted laser light with "markers" that allow the travel time to be determined after reception.

A reference wave can now be stored as a local oscillator using the optical storage ring 38 to perform heterodyne detection. For this purpose, light from the laser 24 is fed into the optical storage ring 38 via an optical connection 27 and forms the reference wave. Optical splitters or beam dividers (not shown) are provided in the region of the delay lines 26 to divert laser light to the optical storage ring 38. The optical storage ring 38 is connected to the detection center 34 via another optical connection 33, where the laser light 53 received by the optical heads 12 is optically mixed with the laser light from the optical storage ring 38.

Since the laser light in the optical storage ring 38 originates from the laser 24, its frequency is known, and since the laser 24 also supplies the optical heads 12 with laser light via the optical outputs 28, the laser light received via the optical heads 12 and the laser light stored in the optical storage ring 38 is also coherent, so that after mixing in the optical detection center 34, detection can be carried out using the hydronym method.

In addition to controlling the laser 24 as already described, the light electrode center 46 also serves, among other things, to control the detectors in the optical detection center 34, A/D converters in the processor 40, and the scanning device in the optical heads 12, which is designed as an Optical Phased Array (OPA) 52 (see also 6 The electrical connections between these elements are not shown for the sake of clarity.

As previously explained, the laser 24 can consist of a single laser or, in a scalable manner, have multiple lasers to adapt the lidar central unit 14 to a different number or power requirement of optical heads 12. Depending on the method used (time-division multiplexing or FMCW), the detection center 34 will have either only one detector or one detector per optical head 12 to convert the received laser light into electrical signals.

In particular, the optical outputs 28 and the optical inputs 30 can be provided as optical connectors, so that coupling or decoupling of the optical heads 12 can be implemented particularly easily and reliably.

6 Figure 1 shows a schematic view of an optical head 12. Optical connections are represented by solid lines, electrical connections by dashed lines. The optical connections can contain multimode or single-mode optical fibers or polarization-maintaining optical fibers. The optical head 12 has an optical connector 68, through which it is optically connected to the lidar central unit 14 via the optical fiber connections 70 and 72. The optical head 12 is also connected to the lidar central unit 14 via an electrical interface 66 and the electrical connection 74.

The electrical connection 74 is used in particular for the control of the Optical Phased Array 52.

The laser light from the lidar central unit 14 is guided from the optical connectors 68 via optional optical components 60 to a transfer structure 58. The optional optical components 60 can function as polarization filters in combination with a lambda/2 plate as a polarization setter. This enables polarimetric measurements or scans to be performed. In this case, polarization-maintaining optical fibers are used for further light transmission.

A transfer structure 58 serves to connect a coupling structure 56, by means of which laser light to be emitted from the lidar central unit 14 is coupled into the optical phased array 52 and received reflected laser light is directed back towards the fiber optic connection 72.

The Optical Phased Array 52 controls the scanning process, in which emitted light is used to measure the scanning process. The environment is cyclically scanned using laser light 51 and received reflected laser light 53. Two different line arrays can be provided for transmission and reception, but preferably this is done with a corresponding time offset in a single line array.

Laser light 53 reflected from the environment is received via an optical input element 54 and directed to the optical phased array 52. The input element 54 can include an input surface and a lens structure for this purpose.

At least one or more elements of the group comprising the optical output 50, the optical phased array (OPA) 52, the optical input surface 54, the coupling structure 56, and the transfer structure 58 can be integrated into a photonic chip 62. Such a photonic chip 62 incorporates integrated optical circuits and is a microchip containing two or more photonic components, which can also form a circuit. This technology detects, generates, transmits, and processes light.

7 shows the connections between the lidar central unit 14 and the exemplary optical head 12 of the 6 The first optical fiber connection 70 and the second optical fiber connection 72 are provided between the optical head 12 and the lidar central unit 14. The first optical fiber connection 70 serves to transmit laser light emitted by the laser 34 in the lidar central unit 14 to the optical head 12. Conversely, the second optical fiber connection 72 serves to transmit laser light received by the optical head 12 back to the lidar central unit 14. The electrical connection 74 between the lidar central unit 14 and the optical head 12 is also shown; this connection, which serves as a data line and/or control line, controls the scanning device provided in the optical head 12.

The present invention thus offers significant advantages over known lidar devices. In particular, the size of the optical heads 12 can be drastically reduced by relocating the light generation to the lidar central unit 14, where it is provided by the laser 24. The installation space required for an optical head 12 is further reduced because the encapsulation of received reflected laser light no longer takes place in the optical head 12, but rather in the detection center 34 within the lidar central unit 14. The optional provision of a timing master 36 and time-division multiplexer enables a time-division multiplexing method, so that, for example, the laser 24 can actually be implemented by a single high-power laser or by multiple lasers, with the number of multiple lasers being smaller than the number of optical heads 12. The optical delay lines 26 are also used for this purpose. As already explained, the alternative FMCW method allows the application of a heterodyne detection method, which significantly improves the sensitivity of the system and thus the range of a lidar device according to the invention. The time-division multiplexing method can also be used to employ a weaker laser instead of a strong light source, i.e., a strong laser 24. The emitted light power can be distributed to the various optical heads 12 in a time-staggered manner using the delay lines 26. The provision of multiple optical heads offers redundancy advantages.

Reference symbol list

10

vehicle

12

optical head

14

Lidar central unit

16

Scan lines

18

Scan lines

20

Scan line

22

Scan line

24

Laser

25, 27, 29, 31, 33

optical connection

26

Optical delay lines

28

optical outputs

30

optical inputs

32

electronic inputs/outputs

34

Detection center

36

Timing Master and Time Multiplexer

38

optical storage ring

40

processor

42

Merger Center

44

Cooling device

46

Lighting Electronics Center

48

Data interface

50

optical output in the surrounding area

51

emitted laser light

52

Optical Phased Array (OPA)

53

received laser light

54

optical entrance area

56

Coupling structure

58

handover structure

60

optical component

62

Potentiation chip

64

optical output signal

66

electrical interface

68

optical extension connections

70, 72

Fiber optic connection

74

electrical connection

Claims (15)

Lidar device for detecting the surroundings of a vehicle (10), wherein the lidar device comprises: at least one laser (24) for emitting laser light, at least one optical head (12) for emitting the laser light (51) into the surroundings and for receiving laser light (53) reflected from the surroundings, and at least one detector for converting received laser light into electrical signals, characterized in that: a lidar central unit (14) is provided in which the at least one laser (24) and the at least one detector are arranged, and optical fiber connections (70, 72) are arranged between the optical head(s) and the lidar central unit (14), which are configured to transmit emitted laser light from the at least one laser (24) to the optical heads (12) and/or received laser light (53) from the optical heads (12) to the at least one detector. lead. Lidar device according to Claim 1 , characterized in that each optical head (12) has a scanning device for spatial scanning of the environment, wherein the scanning device preferably has at least one Optical Phased Array (52) which can be controlled by the lidar central unit (14). Lidar device according to Claim 2 , characterized in that an electrical connection (74) is provided between the lidar central unit (14) and the scanning device, which is configured to transmit control signals from the lidar central unit (14) to the scanning device, or that one of the optical fiber connections (70, 72) is used for this purpose. Lidar device according to one of the preceding claims, characterized in that the single laser (24) or several lasers are arranged in the lidar central unit (14) to emit laser light which can be distributed to the plurality of optical heads (12), wherein the number of optical heads (12) is preferably greater than the number of lasers (24). Lidar device according to one of the preceding claims, characterized in that a first optical fiber connection (70) is arranged between the lidar central unit (14) and each optical head (12), which is configured to guide emitted laser light from the lidar central unit (14) to the optical head (12), and a second optical fiber connection (72) is configured to guide received laser light from the optical head (12) to the lidar central unit (14). Lidar device according to one of the preceding claims, characterized in that an optical fiber connection is arranged between the lidar central unit and each optical head, which is configured to both direct emitted laser light from the lidar central unit to the optical head and to direct received laser light from the optical head to the lidar central unit. Lidar device according to one of the preceding claims, characterized in that optical delay lines (26) are provided in the lidar central unit (14) or between the lidar central unit (14) and one or each optical head (12). Lidar device according to one of the preceding claims, characterized in that at least one or each optical head (12) can receive laser light which has been emitted by another or a plurality of other optical heads (12) and reflected by the environment. Lidar device according to one of the preceding claims, characterized in that at least one or each optical head (12) includes a temperature measuring point, which is preferably designed to allow temperature-dependent adjustments of a component in the optical head, preferably an Optical Phased Array (52) of a scanning device. Lidar device according to one of the preceding claims, characterized in that amplitude switches are provided in the lidar central unit (14) to control the intensity of emitted light supplied to or received by the optical heads (12) and/or optical fiber connection (70, 72). Lidar device according to one of the preceding claims, characterized in that the optical fiber connections (70, 72) can also be used for optical data transmission. A method for operating a lidar device, wherein in the course of the method: Laser light is emitted from one or more lasers (24) of a lidar central unit (14), the emitted laser light is supplied via fiber optic connections (70) to a plurality of optical heads (12) and emitted by them into an environment, laser light reflected from the environment is received by the optical heads (12) and supplied via the or further fiber optic connections (70, 72) to the lidar central unit (14) and converted into electrical signals by at least one detector of the lidar central unit (14), whereby laser light which is emitted by an optical head (12) into the environment and reflected by it is received by the same and/or by one or a plurality of other optical heads (12). Proceedings Claim 12 , wherein in each optical head (12) a scanning method is applied to vary the direction of the emitted and/or received laser light, wherein preferably different optical heads (12) perform different one-dimensional scans in a horizontal or vertical or inclined direction. Procedure one of the Claims 12 or 13 , wherein a time-division multiplexing method is used when supplying laser light to the various optical heads (12) and/or when evaluating detected reflected laser light. Procedure one of the Claims 12 or 13 , where a heterodyne method is used to detect reflected laser light.