Fiber optic-based LiDAR system

Abstract

LiDAR system (1), comprising: - a beam source (2) which is configured to generate a scan beam (20), - a detector (3) which is configured to detect a reflection of the scan beam (20) which is reflected back to the LiDAR system (1) when the scan beam (20) has been reflected in an environment of the LiDAR system (1), - a bundle of optical fibers (4) comprising at least a first optical fiber (5) and a second optical fiber (6), wherein the first optical fiber (5) is coupled to the radiation source (2) at a first end of the first optical fiber (5) and the second optical fiber (6) is coupled to the detector (3) at a first end of the second optical fiber (6), and - a sensor head (7) in which a second end of the first light guide (5) and a second end of the second light guide (6) are joined, the sensor head (7) further comprising a deflection device (10) to deflect the scan beam (20) guided via the first light guide (5) to the sensor head (7) in a changing direction during a scanning process, characterized in that - that the first optical fiber (5) and the second optical fiber (6) are arranged coaxially to each other at their second end, or - that the LiDAR system (1) comprises several second optical fibers (6) which are coupled at their first end to the detector (3) and which are joined at their second end to the sensor head (7) with the second end of the first optical fiber (5), wherein the second ends of the second optical fibers (6) are arranged such that they are arranged around the second end of the first optical fiber (5).

Description

State of the art

[0001] The present invention relates to a LiDAR system.

[0002] Laser scanners are used today to capture and recognize objects in three-dimensional space. These laser scanners are also known as LiDAR systems. Currently, so-called macro scanners are predominantly used, but these exhibit a high failure rate due to the high wear of their axis bearings. This problem arises with both motorized rotating mirror scanners and systems with rotors that incorporate laser detectors and optics. In current LiDAR systems, it is essential that rotating components are rotationally symmetrical to avoid mechanical instabilities that can result from imbalances in rotating parts. Furthermore, these systems cannot be built modularly and require a specific design and construction method.

[0003] In some LiDAR systems, the transmit and receive paths of the LiDAR system are biaxially configured, whereby the separate receive and transmit paths result in a large build volume for the laser scanning system.

[0004] Furthermore, current LiDAR systems combine a detector unit, a laser unit and an optical transmit and receive element in one module, which means that the overall volume of such a LiDAR system has a lower limit and the possibilities for selecting an installation location are limited by the overall volume.

[0005] A major cost factor in all these LiDAR systems is the bandpass filter used, which suppresses interfering ambient light. The cost of this filter scales directly with its surface area.

[0006] WO2012112683A2 discloses a LiDAR system that uses optical fibers. A circulator is employed to either couple a transmitted scan beam into an optical fiber or to direct a received reflection of the scan beam to a detector. However, such a circulator makes the deployment of a LiDAR system very expensive and complex, and is therefore not well-suited for use in automotive applications.

[0007] DE102012025464A1 further discloses an optical sensor suitable for use in automotive environments. However, this optical sensor is not suitable for scanning the environment.

[0008] DE 101 46 808 A1 discloses a LiDAR system according to the preamble of the independent claim.

[0009] DE 697 14 334 T2 further discloses a device for deflecting a scan beam. Document EP 2 309 293 A1 discloses a fiber optic scanner in which transmit and receive light are guided coaxially through a single central light guide. This central light guide is divided into an inner cross-sectional area for transmitting light and an outer, annular cross-sectional area for receiving light. A rotating reflector sequentially directs the transmitted light from the central light guide to the ends of a light guide array and, conversely, directs the light received by the light guide array into the annular area of ​​the central light guide.

[0010] Document US 2014 / 0231647 A1 discloses a fiber optic scanning system in which the end of an optical fiber is set into an oscillating motion by a piezoelectric actuator to scan a light beam. The transmitting and receiving light are guided through a common optical fiber that has an inner core for the transmitting light and an outer core for the receiving light. A position sensor is provided to determine the instantaneous position of the oscillating optical fiber end and thus the direction of the emitted beam.

[0011] Document US 5,317,148 A discloses a fiber-optic scanner in which one end of an optical fiber is moved by electromagnetic actuators to scan a field of view. A magnetic element attached to the optical fiber is deflected by orthogonally arranged pairs of electromagnets to create a two-dimensional scanning motion. Transmitting and receiving light are guided through the same optical fiber via a coupler that connects a laser diode to a detector. Disclosure of the invention

[0012] The LiDAR system according to the invention comprises a beam source, a detector, a fiber optic bundle, and a sensor head. The beam source is configured to generate a scan beam. The detector is configured to detect a reflection of the scan beam that is reflected back to the LiDAR system when the scan beam is reflected into the vicinity of the LiDAR system. The fiber optic bundle comprises at least a first fiber optic cable and a second fiber optic cable, wherein the first fiber optic cable is coupled to the beam source at a first end and the second fiber optic cable is coupled to the detector at a first end.In the sensor head, a second end of the first light guide and a second end of the second light guide are joined, the sensor head further comprising a deflection device to direct the scan beam guided to the sensor head via the first light guide in a changing direction during a scanning process.

[0013] Thus, the sensor head and the detector are coupled to each other via a different optical fiber than the sensor head and the light source. This means that an optical path exists at all times between the sensor head and the detector, as well as between the sensor head and the light source. The light source is a light source that provides light in the visible or invisible range. The light provided by the light source is coupled into the first optical fiber. In particular, the light source is a laser. The detector is a device that detects light received by the LiDAR system.

[0014] The detector preferably comprises one or more photodiodes. The detector is thus a sensor or a sensor array. The optical fiber bundle is a strand of several individual optical fibers, wherein the optical fiber bundle comprises at least two individual optical fibers. It is not absolutely necessary that the individual optical fibers are bundled together along the entire length of the optical fiber bundle. An optical fiber is, in particular, an optical fiber. For example, an optical fiber is a glass fiber or a plastic fiber. An optical fiber is an optical component through which light is guided along a structure of the optical fiber. The optical fiber is, in particular, a flexible element or a rigidly shaped element, which is, for example, made of glass or acrylic glass.

[0015] The sensor head is a physical unit that forms the interface between the LiDAR system and its environment. Within the sensor head, the second end of the first optical fiber and the second end of the second optical fiber are joined. This results in a Y-shaped optical fiber bundle, where the first optical fiber from the light source merges with the second optical fiber from the detector. The first and second optical fibers are separate components, but they are bundled together to be compactly arranged side-by-side within the sensor head.

[0016] The deflection device is an optical device capable of directing the scan beam exiting the first optical fiber in different directions, thus enabling scanning of the LiDAR system's surroundings. The scan beam can either be coupled into the first optical fiber as a focused beam or focused into a beam only upon exiting the first optical fiber. The deflection device is also specifically designed to couple a scan beam reflected from the LiDAR system's surroundings into the second optical fiber.

[0017] By separating the sensor head from the detector and the light source via the fiber optic bundle, the modularity of the LiDAR system is increased. This allows the detector and light source to be installed in different positions, while only the sensor head needs to be positioned in a location advantageous for scanning the LiDAR system's surroundings. The sensor head can be designed as an extremely compact unit, enabling flexible positioning. Unlike a complete sensor consisting of a laser detector, deflection unit, and optics, the light source and detector can thus be combined into a single module that can be positioned independently of the sensor head. The light source, detector, and sensor head can be spatially separated.The size of a necessary bandpass filter can be limited to the size of the second optical fiber and thus made very small. For example, the first and second optical fibers can each have an advantageous diameter of less than 1 mm. This enables a cost reduction in the construction of LiDAR systems.

[0018] The sensor head thus combines a transmitter and a receiver path of the LiDAR system. Compared to other coaxial receive and transmit path concepts, no beam splitter is required to separate the emitted light, i.e., the scan beam, from the light reflected from the surroundings of the LiDAR system to be received. The LiDAR system according to the invention ensures that, firstly, more light is available at the detector and, secondly, that the full power of the scan beam is available. Losses caused by a beam splitter are avoided.

[0019] By separating the sensor head, light source, and detector, the light source, detector, and sensor head can be arranged independently. This allows the individual elements of the LiDAR system to be positioned more precisely, particularly within a vehicle. The sensor head requires only a very small installation volume and can therefore be placed, for example, behind a bumper or in a side mirror. This results in a high degree of flexibility regarding the installation location of the light source and detector. The installation location of the individual components can also be chosen advantageously; for example, the light source or detector can be positioned in such a way as to ensure cooling of these components. Because one of the LiDAR system's receiving paths is concentrated on the second optical fiber, the detector can be designed cost-effectively as a compact single-pixel detector.This results in low manufacturing costs for the detector due to the small pixel area. Furthermore, such a single-pixel detector eliminates the need for complex electronics for reading the detector data.

[0020] According to a first alternative, the first and second optical fibers are arranged coaxially at their respective ends. This means that the first and second optical fibers have parallel axes to each other on the sides of the sensor head, at least for a final section of the fiber bundle. This allows a single optical system to be used for both the transmit and receive paths of the LiDAR system. The sensor head can therefore be designed to be particularly compact.

[0021] According to one alternative approach, the LiDAR system comprises several secondary optical fibers, coupled to the detector at their first end and joined at their second end to the sensor head with the second end of the first optical fiber. This provides a larger area at the second end of the secondary optical fiber to couple received light into it. Therefore, focusing the received light onto the secondary optical fibers is simplified, and the receiving optics can be designed more compactly.

[0022] The ends of the second optical fibers are arranged such that they surround the ends of the first optical fiber. In other words, the first optical fiber at the sensor head is a central optical fiber of the optical fiber bundle. The second optical fibers are arranged in a ring around the first optical fiber. It is also advantageous if the LiDAR system comprises several first optical fibers, the first ends of which are coupled to the light source and whose second ends are joined at the sensor head to the ends of the second optical fibers. Preferably, all of the first optical fibers are arranged in the center of the optical fiber bundle and are surrounded by the second optical fibers. This creates a symmetrical structure, allowing the optics of the deflection device to be designed to be particularly compact and simple.

[0023] The dependent claims describe preferred embodiments of the invention.

[0024] It is advantageous to arrange a beam-shaping lens at the second end of the first optical fiber. Such a beam-shaping lens is preferably applied directly to the second end of the first optical fiber. A beam-shaping lens is an optical lens. It allows for the focusing of light coupled from the light source into the first optical fiber. The scan beam can thus be focused before being emitted into the environment of the LiDAR system, and the LiDAR system can be optimized for a preferred scan range.

[0025] It is also advantageous to have a bandpass filter at the second end of the second optical fiber, and / or for the second optical fiber to have a fiber core with an integrated Bragg grating. If the LiDAR system comprises several second optical fibers, it is advantageous to have a bandpass filter at the second end of all of them. The bandpass filter is preferably applied directly to the second end(s). Because only light passed through the second optical fiber reaches the detector, the bandpass filter can be made particularly small. If the bandpass filter is applied directly to the second optical fiber, it can be very narrow, due to the limited angle of incidence for coupling light into the second optical fiber. Preferably, the bandpass filter has a thickness of less than 4 nm.Such a bandpass filter offers advantages when using SPAD detectors, also known as single-photon averaging diodes. Bandpass filters with a narrow transmission band are beneficial for SPAD detectors because they significantly suppress background light. If the second optical fiber has a fiber core with an integrated Bragg grating, an additional, separate filter is unnecessary, as the second optical fiber itself exhibits bandpass characteristics. However, the bandpass filter does not necessarily have to be thinner than 4 nm, since dielectric filters typically consist of multiple layers and can therefore have a thickness of one or more micrometers, depending on the number of layers.

[0026] Furthermore, it is advantageous if the deflection device comprises a movable micromirror and / or a movable first lens arrangement. Such optical elements allow for a particularly simple implementation of the deflection device.

[0027] Furthermore, it is advantageous if the deflection device comprises a first lens arrangement and a second lens arrangement, which are movably arranged relative to each other. It is advantageous if the optical axes of a lens in the first lens arrangement and a lens in the second lens arrangement are aligned parallel to each other, and the lens arrangements are movable relative to each other along the optical axis or in a direction perpendicular to the optical axis. In other words, it is advantageous if the first lens arrangement and the second lens arrangement are not tilted relative to each other. In this way, a particularly compact deflection device with a shallow depth can be created. This results in a compact sensor head.Furthermore, the first lens arrangement and / or the second lens arrangement can also be a microlens array, which has the advantage that the deflection, compared to normal lenses, takes place on the micrometer scale.

[0028] Furthermore, it is advantageous if a third lens arrangement is arranged between the first and second lens arrangements. It is particularly advantageous if the first and second lens arrangements each comprise at least one concave lens, and the third lens arrangement comprises at least one convex lens. Alternatively, the third lens arrangement preferably comprises at least one concave lens. In this way, it can be avoided that light from the scan beam strikes the edge regions of lenses in the first or second lens arrangements, since it can be focused accordingly by the third lens arrangement. This minimizes losses in the transmit and / or receive path of the LiDAR system.

[0029] It is also advantageous if the first and second optical fibers are photonic crystal fibers, with the cavities between the fibers filled with a gas that transmits only light with a wavelength of the light source. The gas acts as a bandpass filter and blocks interfering wavelengths.

[0030] It is also advantageous if the deflection device is a non-mechanical beam steering device. Such a non-mechanical beam steering device is based, in particular, on beam steering by liquid crystals, by prisms, especially birefringent prisms, or by holograms. By eliminating mechanical components in the sensor head, a particularly robust sensor head is created, which, especially in the automotive sector, allows for advantageous placement of the sensor head on a vehicle. Brief description of the drawings

[0031] Exemplary embodiments of the invention are described in detail below with reference to the accompanying drawing. The drawing shows: Fig. 1 a representation of a vehicle on which two LiDAR systems according to the invention are arranged, Fig. 2 a representation of a first optical fiber bundle, wherein one end face of the optical fiber bundle is shown on the side of a sensor head, Fig. 3 a representation of a second light guide bundle, wherein one end face of the light guide bundle is shown on the side of the sensor head, Fig. 4 a representation of a first advantageous sensor head with a first deflection device, Fig. 5 a representation of a second advantageous sensor head with a second deflection device, Fig. 6 an enlarged view of the second deflection device, Fig. 7 a representation of a third deflection device, Fig. 8 a representation of a fourth deflection device, Fig. 9 a representation of a fifth deflection device, and Fig. 10 a representation of a vehicle on which several combined LiDAR systems are arranged. Embodiments of the invention

[0032] Fig. Figure 1 shows a representation of a vehicle 100 in which an exemplary LiDAR system 1 according to the invention is arranged. The LiDAR system 1 comprises a beam source 2, a detector 3, a fiber optic bundle 4 and a sensor head 7.

[0033] The beam source 2 is configured to generate a scan beam 20. The beam source 2 is a laser system. Specifically, the beam source 2 includes a laser diode for generating the scan beam 20.

[0034] Detector 3 is configured to detect a reflection of the scan beam 20 that is reflected back to the LiDAR system 1 when the scan beam 20 is reflected in the vicinity of the LiDAR system 1. Detector 3 comprises a photoactive component, in particular a photodiode. Alternatively, detector 3 is a detector array comprising several photoactive components.

[0035] The optical fiber bundle 4 is a Y-shaped optical fiber bundle. This means that the optical fibers 5 and 6 are bundled at one end of the optical fiber bundle 4 and separated at the other end. The optical fiber bundle 4 comprises at least one first optical fiber 5 and one second optical fiber 6. The optical fiber bundle 4 thus comprises at least two individual optical fibers 5 and 6. These individual optical fibers are bundled, with the bundling occurring only on one side of the first optical fiber 5 and the second optical fiber 6 belonging to the sensor head 7. The first optical fiber 5 and the second optical fiber 6 are therefore bundled in the region of the base of the Y-shaped optical fiber bundle 4.

[0036] The first optical fiber 5 is coupled to the light source 2 at one end. The second optical fiber 6 is coupled to the detector 3 at one end. The other ends of the first optical fiber 5 and the second end of the second optical fiber 6 are bundled on the sensor head 7. The first optical fiber 5 and the second optical fiber 6 are optical fibers. However, it should be noted that the optical fibers can also be made of plastic. Other light-conducting materials can also be advantageous for the optical fibers 5 and 6.

[0037] In the sensor head 7, the second end of the first light guide 5 and the second end of the light guide 6 are joined. This is exemplified in the Fig. 2 and Fig. 3 shown. These include the Fig. 2 and Fig. The light guide bundle 4 shown in Figure 3 contains several second light guides 6, which are coupled at their first end to the detector 3 and which are joined at their second end to the sensor head 7 with the second end of the first light guide 5. In other words, the light source 2 is coupled to the sensor head 7 via a light guide, namely the first light guide 5. The detector 3 is coupled to the sensor head 7 via a multitude of light guides, here the second light guides 6. Thus, each of the light guides that connects the detector 3 to the sensor head 7 can be considered a second light guide 6. Fig. 2 and Fig. Figure 3 shows a top view of one end of the optical fiber bundle 4. The first optical fiber 5 is located in the center of the optical fiber bundle 4. The second optical fibers 6 are arranged around the second end of the first optical fiber 5 shown. Fig. 2 and Fig. Three different arrangement possibilities of the light guides 5, 6 are shown.

[0038] Thus, in Fig. 2. An arrangement of the first optical fiber 5 and the second optical fiber 6 was chosen in which the respective cross-sectional centers of the individual optical fibers 5, 6 are arranged on a square grid. In the Fig. In the advantageous arrangement of the optical fibers 5, 6 shown in Figure 3, the second optical fibers 6 are arranged with their cross-sectional centers on a circular path around the first optical fiber 5. This enables a particularly compact arrangement of the individual optical fibers 5, 6. Fig. 2 and Fig. Figure 3 shows the respective second end of the first optical fiber 5 and the second optical fiber 6. One end face of the optical fiber bundle 4 is depicted. The axes of all optical fibers 5 and 6 are perpendicular to the plane shown in this region of the optical fiber bundle 4. Thus, the axes of the first optical fiber 5 and the second optical fiber 6 are coaxial with each other.

[0039] It is also advantageous to use a double-clad fiber. The inner core of the double-clad fiber is suitable for a single-mode beam from a light source, into which the light is coupled. Thus, the core of the double-clad fiber preferably serves as the first optical fiber 5. The outer cladding of the double-clad fiber (optionally including a bandpass filter or Bragg grating) can collect the reflected light and direct it to the detector. Thus, the outer cladding of the double-clad fiber preferably serves as the second optical fiber 6. This arrangement is similar to Fig. 2 and Fig. 3.

[0040] Other fiber layouts differ from Fig. 2 and Fig. 3. In such other fiber configurations, there is only one waveguide, and this is suitable for slow deflections of the mechanical unit. Furthermore, fiber splitters with or without an integrated beam splitter (possibly polarization-preserving) and / or with any splitting ratio between the individual fibers, i.e., between the first optical fiber 5 and the second optical fiber 6, can be used.

[0041] Furthermore, an optical fiber circulator is advantageous. Light from the light source is coupled into a first port and coupled out via a second port. Thus, ambient light, which is re-coupled via the deflection unit, is sent to the detector via the second port and / or a third port.

[0042] The optical fiber bundle 4 is an optical fiber consisting of several fiber cores. This can also be a photonic crystal fiber. The central fiber core, i.e., the first optical fiber 5, is used to transport the emitted light from a laser or LED, which serves as the beam source 2. The outer fiber cores, i.e., the second optical fibers 6, which can be arranged arbitrarily, collect the light reflected from the vicinity of the LiDAR system 1. A rectangular or circular arrangement, as well as a multi-layered arrangement, is possible for the second optical fibers. To shape the emerging laser beam, i.e., the scan beam 20, an optical element (lens) can be applied to the central fiber core, and thus to the first optical fiber.To suppress background light, a coating (for wavelength selection) can be applied to the outer fiber cores, which is referred to below as a bandpass filter or bandpass filter. Furthermore, it is advantageous to use fiber cores with integrated Bragg gratings instead of a bandpass filter.

[0043] When using photonic crystal fibers as optical fibers 5, 6, the cavities between the individual optical fibers 5, 6 or between the optical fibers and the beam source, the detector and / or the deflection device can be filled with a gas that absorbs the broadband background light and transmits only the wavelength of the beam source 2.

[0044] The central fiber from the radiation source 2 and the outer fiber bundles, i.e. the second optical fibers 6, which lead to the detector 3, can be spatially separated from each other by the Y-shape of the entire optical fiber.

[0045] The Fig. 4 and Fig. Figure 5 shows two possible embodiments of the sensor head 7. Fig. Figure 4 shows the end of the light guide bundle 4 located on the side of the sensor head 7. The light guide bundle 4 corresponds to the one shown in Fig. 2 or Fig. Figure 3 shows a light guide bundle 4. The light guide bundle 4 is shown in a cross-sectional plane along a longitudinal axis of the light guide bundle 4. The first light guide 5 is arranged in the center of the light guide bundle 4. Coaxial to the first light guide 5, a second light guide 6 is arranged above and below it in the cross-section. The light guides 5, 6 of the light guide bundle 4 are further encased with a protective layer 8. A beam-shaping lens 12 is arranged on the second end of the first light guide 5 shown. This lens is mounted directly on the first light guide 5. The beam-shaping lens 12 enables the scanning beam 20 coupled into the first light guide 5 to be focused. A bandpass filter 9 is arranged around the beam-shaping lens 12 at the ends of the second light guide 6. The bandpass filter 9 is mounted at the ends of the second light guide 6.For this purpose, a front surface of the second light guide 6 is coated with the bandpass filter to block unwanted interference light (e.g. from the sun).

[0046] The in Fig. Figure 4 of the embodiment of the sensor head 7 further shows the deflection device 10, which is used in the Fig. The embodiment shown in Figure 4 comprises a movable micromirror. It can be seen that a scan beam 20 coupled to the first end of the first light guide 5 is focused by the beam-shaping lens 12 and emitted onto the micromirror 11. Since the micromirror 11 is movable, the scan beam 20 is emitted in different directions when the micromirror 11 moves. This allows the LiDAR system 1 to scan its surroundings. The micromirror 11 preferably performs an oscillating movement or is designed as a rotating mirror.

[0047] In Fig. Figure 4 thus represents a combination of a multi-fiber with a deflecting mirror, e.g., a micromirror or a polygon mirror. In the case of the micromirror, light from the central fiber, i.e., from the first optical fiber 5, strikes the micromirror 11, which deflects the light at a certain angle into the field of view of the LiDAR system 1. The reflected light is directed back towards the optical fiber bundle 4 by the micromirror 11, which has meanwhile moved further, and there, depending on the position of the pixel in the field of view, it strikes one of the outer second optical fibers 6. There, the light is guided in the fiber core to the detector 3 and strikes the sensitive sensor area.

[0048] The in Fig. The embodiment of the sensor head 7 shown in Figure 5 essentially corresponds to the one shown in Figure 5. Fig. 4 embodiment of the sensor head 7, wherein the deflection device 10 is located in the Fig. In the embodiment shown in Figure 5, instead of the micromirror 11, a first lens arrangement 13 and a second lens arrangement 14 are provided, which are movably arranged relative to each other. One of the first lens arrangement 13 and the second lens arrangement 14 is arranged in a fixed position relative to the light guide bundle 4, and the other of each of the first and second lens arrangements 13 and 14 is movably arranged relative to the light guide bundle 4. The first lens arrangement 13 and the second lens arrangement 14 are microlens arrays.

[0049] In the case of microlens arrays, the scan beam 20 is deflected into the field of view by the moving first or second microlens array 13, 14. After reflection in the vicinity of the LiDAR system 1, the light falls onto one of the outer second optical fibers 6 due to an oscillating movement of the respective microlens array 13, 14, where the light is directed to the detector 3.

[0050] The in Fig. The deflection device 10 shown in Figure 5 is in Fig. Figure 6 shows an enlarged view, depicting individual beam paths of the scan beam 20 as it passes through the deflection device 10. It is evident that the deflection of the scan beam 20 depends on the position of the second lens arrangement 14 relative to the first lens arrangement 13. Thus, to control the scan beam 20 and enable a scanning process by the LiDAR system 1, the second lens arrangement 14 can be laterally offset or moved relative to the first lens arrangement 13. The distance between the lens arrangements 13 and 14 remains constant. This means that the second lens arrangement 14 is moved parallel to the first lens arrangement 13. As also shown in Figure 6, the second lens arrangement 14 is shifted parallel to the first lens arrangement 13. Fig. As can be seen in Figure 6, this can lead to a defocusing of the scan beam 20, which occurs particularly when a portion of the scan beam 20 strikes areas of the second lens arrangement 13 where individual microlenses 13', 13" of the microlens array meet. However, this effect can be minimized if necessary. For example, defocusing of the scan beam 20 by the deflection device 10 is minimized if a third lens arrangement 15 is additionally arranged between the first lens arrangement 13 and the second lens arrangement 14. This is illustrated by example in Figure 6. Fig. 7 shown.

[0051] Fig. Figure 7 shows that the first lens arrangement 13 and the second lens arrangement 14 are each a lens array of convex microlenses. The third lens arrangement 15 is a lens array of concave microlenses. The third lens arrangement 15 is moved relative to the first lens arrangement 13 together with the second lens arrangement 14. However, it is not necessary for the second lens arrangement 14 and the third lens arrangement 15 to be moved to the same extent relative to the first lens arrangement 13. Rather, it is advantageous if the second lens arrangement 14 and the third lens arrangement 15 are moved such that the scan beam 20 is focused by the third lens arrangement 15 onto the individual microlenses of the second lens arrangement 14.

[0052] In all embodiments of the invention, it is advantageous if the deflection device 10 is a non-mechanical beam-guiding device. This means, for example, that the micromirror 11 or the lens arrangements 13, 14, and 15 do not include any mechanical components that are actually moved. Thus, the lenses of the first, second, and / or third lens arrangement 13, 14, 15 are formed, for example, by a corresponding current applied to a liquid crystal. If the liquid crystal is energized in a different manner, the first to third lens arrangements 10, 13, 14 form at a different position within the liquid crystal. However, the liquid crystal itself is not mechanically moved in any way.Alternative techniques for implementing non-mechanical beam guidance in the deflection device 10 include beam guidance by holograms, birefringent prisms, variably polarizable elements, and liquid crystals. Such devices for non-mechanical beam guidance are known from the prior art and will not be described in detail here for the sake of brevity. The use of non-mechanical beam guidance devices in a sensor head 7 according to the invention is advantageous in every respect, as this increases the robustness of the sensor head 7 against mechanical influences and thus enables a more flexible arrangement of the sensor head 7.

[0053] In the embodiments described above, the first lens arrangement 13, the second lens arrangement 14, and the third lens arrangement 15 are configured as a microlens array. It should be noted, however, that the first lens arrangement 13, the second lens arrangement 15, and / or the third lens arrangement 15 can also be configured as individual lenses. This is shown in Figure 1. Fig. 8 a lens arrangement in the deflection device 10, wherein the first lens arrangement 13 comprises a single convex lens and the second lens arrangement 14 comprises a single convex lens. If the second lens arrangement 14 is moved relative to the first lens arrangement 13, the direction of the scan beam 20 changes. It is also advantageous in an embodiment of the lens arrangements 13, 14 as separate lenses if focusing is achieved between the first lens arrangement 13 and the second lens arrangement 14 by means of a third lens arrangement 15, wherein the third lens arrangement 15 can also be designed as a single lens. This is exemplified in Fig. Figure 9 shows that the third lens arrangement 15 also comprises a single convex lens. As in the case of the one in Fig. In the embodiment of the deflection device 10 shown in Figure 7, the second lens arrangement 14 and the third lens arrangement 15 are movable relative to the first lens arrangement 13.

[0054] It is pointed out that in the Fig. 6, Fig. 7, Fig. 8 and Fig. In the deflection devices 10 shown, the lens arrangements 13, 14, 15 marked by a frame 21 are movably arranged.

[0055] At the in Fig. In the vehicle 100 shown in Figure 1, two identical LiDAR systems 1, 1' are arranged. Fig. Figure 10 shows an alternative arrangement of several LiDAR systems 1 according to the invention on a vehicle 100. Several sensor heads 40, 41, 42, 43 are arranged on the vehicle, corresponding to the sensor head 7 described above. The detectors 3 of the individual LiDAR systems are grouped in a detector assembly 44. The beam sources 2 of the individual LiDAR systems are grouped in a beam source assembly 35. The beam source assembly 45 is designed such that the scan beam 20 is coupled from a single laser into different first optical fibers 5, which belong to different LiDAR systems. The sensor heads 40, 41, 42, 43 of the individual LiDAR systems are arranged at arbitrary positions on the vehicle 100. The entire environment of the vehicle 100 can therefore be scanned by the LiDAR systems, with the necessary detectors 3 and beam sources 2 being safely located inside the vehicle 100.

[0056] The sensor head 7, which includes the deflection unit, can be installed separately from the beam source 2 and detector 3 in the vehicle 100. This allows the sensor head 7 to be installed in locations with limited space, for example, in the vehicle door. The beam source 2 and detector 3, including the electronics, can be mounted in easily accessible locations where sufficient space is available for the modules. When using multiple sensors, the beam sources 2 and detectors 3 can be connected to form a single unit.

[0057] The application area of ​​a LiDAR system according to the invention includes, in particular, 2D and 3D laser scanners for environmental perception in driver assistance systems, especially in the context of highly automated driving. Furthermore, its use in other areas is advantageous, for example in service robotics, gesture recognition (e.g., for mobile devices or in vehicle interiors), and workplace monitoring.

[0058] In addition to open revelation, explicit reference is made to the revelation of Fig. References are made to 1 to 10.

Claims

[1] LiDAR system (1), comprising: - a beam source (2) which is configured to generate a scan beam (20), - a detector (3) which is configured to detect a reflection of the scan beam (20) which is reflected back to the LiDAR system (1) when the scan beam (20) has been reflected in an environment of the LiDAR system (1), - a bundle of optical fibers (4) comprising at least a first optical fiber (5) and a second optical fiber (6), wherein the first optical fiber (5) is coupled to the radiation source (2) at a first end of the first optical fiber (5) and the second optical fiber (6) is coupled to the detector (3) at a first end of the second optical fiber (6), and - a sensor head (7) in which a second end of the first light guide (5) and a second end of the second light guide (6) are joined, the sensor head (7) further comprising a deflection device (10) to deflect the scan beam (20) guided via the first light guide (5) to the sensor head (7) in a changing direction during a scanning process, characterized by , - that the first optical fiber (5) and the second optical fiber (6) are arranged coaxially to each other at their second end, or - that the LiDAR system (1) comprises several second optical fibers (6) which are coupled at their first end to the detector (3) and which are joined at their second end to the sensor head (7) with the second end of the first optical fiber (5), wherein the second ends of the second optical fibers (6) are arranged such that they are arranged around the second end of the first optical fiber (5). [2] LiDAR system (1) according to any one of the preceding claims, characterized by , that a beam shaping lens (12) is arranged at the second end of the first light guide (5). [3] LiDAR system (1) according to any one of the preceding claims, characterized by , that a bandpass filter (9) is arranged at the second end of the second optical fiber (6) and / or the second optical fiber (6) has a fiber core with an integrated Bragg grating. [4] LiDAR system (1) according to any one of the preceding claims, characterized by , that the deflection device (10) comprises a movably arranged micromirror (11) and / or a movably arranged first lens arrangement (13). [5] LiDAR system (1) according to any one of the preceding claims, characterized by, that the deflection device (10) comprises a first lens arrangement (13) and a second lens arrangement (14) which are arranged to be movable relative to each other, wherein a third lens arrangement (15) is preferably arranged between the first lens arrangement (13) and the second lens arrangement (14). [6] LiDAR system (1) according to any one of the preceding claims, characterized by , that the first optical fiber (5) and the second optical fiber (6) are photonic crystal fibers, wherein the cavities between the optical fibers (5, 6) are filled with a gas which transmits only light with a wavelength of the beam source (2). [7] LiDAR system (1) according to any one of the preceding claims, characterized by , that the deflection device (10) is a non-mechanical beam deflection device.

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