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DE-102024133103-A1 - Lidar device

DE102024133103A1DE 102024133103 A1DE102024133103 A1DE 102024133103A1DE-102024133103-A1

Abstract

The present invention relates to a lidar device for detecting the surroundings of a vehicle, wherein the lidar device comprises a laser light source (12) and a first optical head (18) with an optical transmitter and receiver unit (48) for emitting the laser light and for receiving laser light reflected from the surroundings. A detector (14) is provided for converting received laser light into electrical signals. According to the invention, the lidar device further comprises at least one additional optical head (22) with an optical transmitting and receiving unit (48) for emitting the laser light into the environment and for receiving laser light that has been reflected from the environment, wherein optical connections (16, 20) are provided to guide the laser light emitted by the laser light source (12) first to the first optical head (18) and from there to the additional optical head (22).

Inventors

  • Jonathan Fischer
  • Aurora Baruzzi

Assignees

  • BAYERISCHE MOTOREN WERKE AKTIENGESELLSCHAFT

Dates

Publication Date
20260513
Application Date
20241112

Claims (15)

  1. A lidar device for detecting the surroundings of a vehicle, wherein the lidar device comprises: a laser light source (12) for emitting laser light, a first optical head (18) with an optical transmitter and receiver unit (48) for emitting the laser light into the surroundings and for receiving laser light reflected from the surroundings, and a detector (14) for converting received laser light into electrical signals, characterized in that: the lidar device further comprises: at least one additional optical head (22) with an optical transmitter and receiver unit (48) for emitting the laser light into the surroundings and for receiving laser light reflected from the surroundings, wherein optical connections (16, 20) are provided to guide the laser light emitted by the laser light source (12) first to the first optical head (18) and from there to the additional optical head (22).
  2. Lidar device according to Claim 1 , characterized in that the optical connections (16, 20) or further optical connections (24, 26) are provided to direct laser light received from the first optical head (18) to the detector (14), and to direct laser light received from the further optical head (22) to the first optical head (18) and from there to the detector (14).
  3. Lidar device according to one of the preceding claims, characterized in that the lidar device includes a plurality of optical heads (18, 22) which are connected in a chain-like manner, and optical connections (16, 20) are provided for transmitting laser light to be emitted to an optical head from an upstream optical head, and optionally further optical connections are provided for transmitting laser light received from downstream optical heads to an optical head.
  4. Lidar device according to one of the preceding claims, characterized in that the lidar device has a master unit (10) which includes the laser light source (12) and the detector (14).
  5. Lidar device according to Claim 4 , characterized in that the master unit (10) has a planning unit (52) which is designed to assign a transmit and/or receive schedule to each optical head (18, 22).
  6. Lidar device according to Claim 4 or 5 , characterized in that the master unit (10) or each optical head (18, 22) has a delay line (56) which is provided to store a portion of the laser light emitted by the laser light source (12) and to make it available to the detector (14) for carrying out a dedicated heterodyne process.
  7. Lidar device according to one of the preceding claims, characterized in that each optical head (18, 22) has an optical amplifier (32) which is provided to amplify emitted laser light which is transmitted to the subsequent optical head prior to transmission.
  8. Lidar device according to one of the preceding claims, characterized in that each optical head (18, 22) has an optical combiner (44) which is provided to combine light received by this optical head (18) with light received by at least to combine the signal received by a downstream optical head (22).
  9. Lidar device according to one of the preceding claims, characterized in that each optical head (18) has a splitter (28) which is provided to direct emitted light proportionally to an optical transmitting unit (48) of this optical head and to at least one downstream optical head (22).
  10. Lidar device according to one of the preceding claims, characterized in that each optical head (18) has a variable optical delay generator (36) which is provided to control the timing of the forwarding of emitted laser light which is transmitted to the downstream optical head (22).
  11. Lidar device according to one of the preceding claims, characterized in that the lidar device is provided for emitting laser light with light of a first linear polarization direction and detecting with laser light of a second linear polarization direction, wherein the first and the second polarization direction are perpendicular to each other.
  12. Lidar device according to one of the preceding claims, characterized in that at least one or all optical connections provided between the laser light source (12) and the detector (14) are designed as fiber optic connections and optionally as polarization-preserving fiber optic connections or as preferably polarization-preserving waveguide structures on a photonic chip.
  13. Lidar device according to one of the Claims 11 until 12 , characterized in that an optical connection (16, 20) is provided between the laser light source (12) and the first optical head (18) and between the further optical heads (22) in order to guide emitted and received laser light of the two linear polarization directions.
  14. Lidar device according to one of the Claims 11 until 13 , characterized in that a polarization splitter (68) is provided in each optical head (18, 22) to direct emitted laser light with the first linear polarization direction to the respective downstream optical head, and laser light received from the downstream optical heads with the second linear polarization direction towards the detector.
  15. Lidar device according to one of the Claims 11 until 14 and after Claim 4 , characterized in that the master unit (10) has the delay line (56), and a polarization rotator (76) is provided between the laser light source (12) and the detector (14) to rotate the first linear polarization direction of the emitted laser light into the second linear polarization direction.

Description

The present invention relates to a lidar device according to the preamble of claim 1. A lidar device of this type is used to detect the surroundings of a vehicle. Such a lidar device includes a laser light source designed to emit laser light. An optical head is provided with an optical transmitter and receiver unit for transmitting the laser light into the surroundings and for receiving laser light reflected from the surroundings. A lidar device of this type also includes a 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 conventional 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. The 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 create 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. According to the invention, the lidar device has at least one further optical head with an optical transmitting and receiving unit for emitting laser light into the environment and for receiving laser light reflected from the environment. Optical connections are provided to guide the laser light emitted by the laser light source first to the first optical head and from there to the further optical head. Preferably, the optical connections installed between the laser light source and the detector will be designed as fiber optic connections or as waveguide structures on a photonic chip. A lidar device according to the invention offers the advantage that only one laser light source is required, which can also be of a modular design. In contrast, no laser light source needs to be provided in the individual optical heads, since each optical head receives laser light emitted by the preceding optical head. Various optical heads are therefore optically connected in series, forming a serial chain. Such a chain is often referred to as a "daisy chain" and includes upstream (arranged before a specific head) and downstream (arranged after a specific head) optical heads. The first advantage of such a daisy chain is the simplicity of its construction, and another is the easy scalability of the lidar device. Thus, depending on the number of optical heads required, an additional optical head can easily be added to an existing lidar device. By using a central laser light source, the installation space required for an optical head can be reduced. This reduction in required installation space results not only from the elimination of laser light sources in the optical heads. Because less heat is generated in the optical heads, less space is needed for heat dissipation. Further preferred embodiments of the present invention are set forth in the dependent claims. In a first preferred embodiment of a lidar device according to the invention, the optical connections or further optical connections are provided to direct laser light received from the first optical head to the detector and to direct laser light received from the further optical head to the first optical head and from there to the detector. This embodiment of the invention offers the advantage that the detector can also be arranged as a single detector or as a detector module in a central unit, thus eliminating the need for a separate detector in each optical head. This also offers the advantage of further reducing the required installation space for the optical heads. Furthermore, since