Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
  • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
  • G01S17/06—Systems determining position data of a target
  • G01S17/42—Simultaneous measurement of distance and other co-ordinates
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
  • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
  • G01S17/06—Systems determining position data of a target
  • G01S17/08—Systems determining position data of a target for measuring distance only
  • G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
  • G01S17/88—Lidar systems specially adapted for specific applications
  • G01S17/93—Lidar systems specially adapted for specific applications for anti-collision purposes
  • G01S17/931—Lidar systems specially adapted for specific applications for anti-collision purposes of land vehicles
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
  • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
  • G01S7/481—Constructional features, e.g. arrangements of optical elements
  • G01S7/4814—Constructional features, e.g. arrangements of optical elements of transmitters alone
  • G01S7/4815—Constructional features, e.g. arrangements of optical elements of transmitters alone using multiple transmitters
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
  • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
  • G01S7/481—Constructional features, e.g. arrangements of optical elements
  • G01S7/4817—Constructional features, e.g. arrangements of optical elements relating to scanning
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
  • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
  • G01S7/483—Details of pulse systems
  • G01S7/484—Transmitters

Definitions

• the invention relates to a range-optimized LiDAR system. Furthermore, the invention relates to a LiDAR device and a control device for such a LiDAR system.
• LiDAR systems are usually designed as rotating scanners, micro-scanners (MEMS mirrors) or flash systems.
• the field of view (FoV) is temporally scanned with a highly collimated laser beam.
• the resolution in the horizontal direction is realized in fine steps with the help of an angle measurement.
• the resolution is determined by the number of transmitter/receiver units.
• Various macro scanners are known from the prior art. This is an optoelectronic sensor in which a macroscopic unit rotates, for example a transmitter or a detector.
• the laser power per measurement pulse is significantly lower in scanning LiDAR systems than in a flash system, since strongly bundled lasers are used here and the receiver ideally only ever observes the small section of the FoV that is actually being illuminated by the laser.
• a macro scanner can also have stationary transmitters and receivers, with the beam deflection being effected by a rotating macroscopic mirror.
• the latter type of sensor is particularly advantageous when a lot of heat has to be dissipated, because a stationary (ie non-rotating) transmitter can be linked particularly effectively to larger heat sinks or other cooling components.
• the object on which the invention is based can therefore be seen as providing a way of improving the range of the LiDAR system, in particular for applications with high driving speeds or large braking masses of the ego vehicle. This object is solved by means of the respective subject matter of the independent claims.
• Advantageous configurations of the invention are the subject matter of the dependent subclaims.
• a LiDAR system for detecting objects within an observation area comprising several detection areas, which has a stationary transmission device comprising a primary transmission module designed to emit a primary laser beam in the form of primary light pulses, each of which illuminates a current detection area of the observation area. and a secondary transmission module that can be selectively connected to the primary transmission module in terms of time and is designed to emit a secondary laser beam in the form of secondary light pulses that illuminate the current detection area at the same time as the primary light pulses.
• the LiDAR system also includes an optical beam combination device designed to combine the primary laser beam and the secondary laser beam to form a combined laser beam, a scanning device designed to generate a scanning movement of the combined laser beam, by which different detection areas of the observation area are illuminated one after the other, and a receiving device with at least a light detector for detecting the light pulses reflected back by objects from the current detection area.
• the LiDAR system includes a control device for controlling the transmission device, the control device being designed to control the emission of the secondary laser beam by the secondary transmission module independently of the emission of the primary laser beam by the primary transmission module. The use of a switchable secondary transmitter module enables an improved maximum range of the LiDAR system.
• the secondary transmission module can serve as a "boost mode" that can be switched on to improve the SNR when there is a lot of background light. Furthermore, the use of a secondary transmission module that can be controlled independently of the primary transmission module results in redundancy, through which defects in one of the two transmission modules can be compensated. In the event of a defective primary or secondary transmitter module, the functional transmitter module continues to operate in a normal operating mode, resulting in a failure of the LiDAR system. If necessary, there is only a degeneration of the driving functions, since the corresponding vehicle may no longer be able to drive as fast.
• SNR Signal-to-noise ratio
• control device is designed to selectively connect the secondary transmission module to the primary transmission module during a scanning process in order to illuminate selected areas of the observation area with a relatively high pulse peak power resulting from the addition of the primary and secondary light pulses.
• the control device is also designed to selectively deactivate the secondary transmission module during the scanning process in order to illuminate non-selected areas of the observation area with a relatively low pulse peak power provided only by the primary light pulses of the primary transmission module.
• a usable signal can be achieved by increasing the pulse peak power. For example, similar to a radar system, you can look further in the middle than to the side, or you can look selectively to the right and left at a crossroads with a longer range for fast approaching vehicles. Furthermore, for autopilot applications (HWP, Highway Pilot), only one's own lane can be selectively measured with a long range. By temporal timing of the secondary pulses, the Activation in the course of the horizontal scan can be selected and controlled from the outside. In addition, curved motorway sections can also be scanned in advance for objects such as "Lost Cargo".
• control device is designed to switch on the second transmission module in order to illuminate at least one of the following areas with a long range, namely a narrow central area in front of an ego vehicle for monitoring its own lane and at least one area to the side of an ego vehicle for detecting approaching vehicles on crossing or intersecting or merging roads.
• a long range namely a narrow central area in front of an ego vehicle for monitoring its own lane and at least one area to the side of an ego vehicle for detecting approaching vehicles on crossing or intersecting or merging roads.
• the optical beam combination device is designed in the form of a deflection mirror with a passage opening.
• the deflection mirror, the primary laser beam and the secondary laser beam are aligned with one another in such a way that a first of the two laser beams passes through the passage opening, while the other of the two laser beams is deflected by the deflection mirror in an edge area of the passage opening in such a way that the two Superimpose laser beams to form the combined laser beam.
• the deflection mirror designed as a perforated mirror enables the two laser beams to be added efficiently at the same time only a very small loss in the receiving path.
• the use of a single component for beam combination enables a relatively small and flat design of the device.
• the transmission device and/or at least one optics optically connected downstream of the transmission device is designed to generate a beam profile in the form of a vertical line for the primary and secondary laser beams.
• the passage opening of the deflection mirror is designed in the form of a vertical slit. This measure allows the observation space to be scanned column by column.
• the specially shaped through opening enables the two linear laser beams to be superimposed particularly well.
• the second transmission module is essentially identical to the first transmission module.
• identical and synchronous light pulses can be generated relatively easily, which can be added particularly well. As a result, particularly high pulse peak powers are achieved.
• use of identical transmission modules also results in cost advantages in production.
• the control device is designed to use that of the two transmission modules as the secondary transmission module which meets at least one of the following criteria, namely that the corresponding transmission module, due to its design, its installation location and/or its relative to the other Transmission module poorer thermal connection to a heat sink has a greater cooling requirement or that the corresponding transmission module has a current higher temperature due to the situation.
• This measure ensures particularly efficient operation that is gentle on the components involved.
• that one of the two transmission modules which would heat up more in normal operation can be selected for the secondary operation. If the transmitter modules are designed identically, it doesn't matter which one in normal operating mode (ie medium range). of the two transmitter modules emits the primary laser beam.
• control device is designed to switch on the second transmission module only when a predefined driving speed of an ego vehicle equipped with the LiDAR system is exceeded. Since the long ranges achieved for the automated driving functions with the help of the switched-on secondary transmitter module are only required at higher speeds and, as expected, at these speeds there are no people in the immediate vicinity of the LiDAR system, an intelligent operating mode can be provided in which the secondary transmitter module only switched on at higher speeds. In this way, eye safety can be guaranteed despite the relatively high pulse peak power.
• the LiDAR system includes an external interface designed to receive control signals via an external signal line.
• the control device is designed to activate and deactivate the secondary transmission module when a corresponding control signal is received via the external interface. Since the external controllability is advantageously available at the system interface, the driving function or the central control computer of the ego vehicle can influence the increase in range depending on the situation.
• the LiDAR system can thus be integrated particularly well into the control concept of automated vehicles.
• a LiDAR device for the LiDAR system described above, which comprises a stationary transmission device, a primary transmission module designed to emit a primary laser beam in the form of primary light pulses, each of which illuminates a current detection area of the observation area, and a to the primary transmission module time-selectively switchable secondary transmission module designed to emit a secondary laser beam in the form of secondary light pulses, which illuminate the current detection area at the same time as the primary light pulses.
• the LiDAR system also includes an optical beam combination device designed to combine the primary laser beam and the secondary laser beam to form a combined laser beam, a scanning device designed to generate a scanning movement of the combined laser beam, by which different detection areas of the observation area are illuminated one after the other, and a receiving device with at least a light detector for detecting the light pulses reflected back by objects from the current detection area.
• a control device for the above-mentioned LiDAR system, wherein the control device is designed to switch the secondary transmission module on to the primary transmission module selectively in terms of time during a scanning process in order to provide selected areas of the observation area with one of the addition of the primary and to illuminate secondary light pulses resulting relatively high pulse peak power.
• the control device is also designed to selectively deactivate the secondary transmission module during the scanning process in order to illuminate non-selected areas of the observation area with a relatively low pulse peak power provided only by the primary light pulses of the primary transmission module.
• FIG. 1 shows a schematic of the functioning of a LiDAR system for detecting objects in an observation area of its surroundings
• FIG. 2 shows schematically the structure of a LiDAR system with a static transmission module and a rotating deflection mirror
• 3 schematically shows the structure of a LiDAR system with two static transmission modules and a rotating deflection mirror
• FIG. 4 shows a schematic diagram with the time profile of the light output of different light pulses of the LiDAR system from FIG. 3;
• FIG. 5 shows a schematic of a vehicle in which a wide detection area with a medium range and a narrow central detection area with a long range are realized with the aid of the LiDAR system;
• FIG. 6 shows a schematic of a vehicle in which a wide detection area with a medium range and two narrow lateral detection areas with a long range are realized with the aid of the LiDAR system.
• the concept described here envisages a pulsed LiDAR system, which is preferably used as a macro scanner with a mirror rotated about the vertical axis, for example by means of an electric drive unit, a one-dimensional transmission and reception path for column illumination and column detection with optional macro-pixel formation in the horizontal and vertical directions, and a stationary laser, detector, electronics and optics.
• a key aspect of the new LiDAR system is a secondary transmitter module that can be switched on independently of the primary transmitter module of the LiDAR system.
• the secondary transmission module is preferably designed identically to the primary transmission module of the LiDAR system, with the wavelength, beam shape, optics, pulse length, pulse frequency, etc. being the same for both transmission modules, so that the same vertical column (laser beam with linear beam profile) as emission results.
• the emission of the secondary transmission module is inserted into the optical path of the primary transmission module in such a way that the columns emitted by the two transmission modules are already added to one another in the device.
• a relatively high pulse peak power and pulse energy is generated, which optionally and controllably enables long-range operation in selected, horizontal solid angles.
• 1 shows a schematic of a LiDAR system 100 scanning its surroundings 200 using a pulsed laser beam 122.
• the LiDAR system 100 comprises a LiDAR device 110 and a control device 190 for controlling the LiDAR device 110.
• the LiDAR device 110 comprises a stationary transmitting and receiving device 111 with a transmitting device 120, which has a transmitting module 121 for generating the laser beam 122, and a receiving device 130, which has an arrangement, not shown here, of at least one detector 131 for detecting the laser beam 122 reflected on objects 201 in Form of a reflected light radiation 129.
• the laser beam 122 scanning the observation area 210 is emitted in the form of a vertical line.
• the corresponding receiving device 130 typically has a detector arrangement 131 with a plurality of detectors arranged vertically one above the other in the form of a detector array.
• the LiDAR device 110 includes an optical device 160 with at least one or more optics, not shown here, for collimating the emitted laser beam 122 and shaping its beam profile and for imaging the received light radiation 129 on the at least one detector 131.
• the LiDAR Device has a scanning device 150, which consists, for example, of a rotating mirror and a suitable motorized drive device (not shown here). With the aid of the scanning device 150 , the laser beam 122 is typically guided in a periodic scanning movement 153 over a defined observation area 210 of the surroundings 200 which defines the current field of view of the LiDAR system 100 .
• the observation area 110 is scanned in small steps, with the light pulses of the pulsed laser beam 122 successively illuminating a small detection area 2111 - 211 , which in each case represents a small section of the observation area 210 .
• the light 129 reflected back by an object 201 from the respective detection region 211i-211 is directed by the scanning device 150 to the receiving device 130 and detected by the at least one detector of the detector arrangement.
• the control device 190 can comprise several components, such as an activation device 191 for Activation of the transmission device 120 or the transmission module 121.
• the control device 190 can also contain further components, such as an evaluation device 192 for evaluating the measurement signals of the at least one detector 131.
• Such an evaluation device 192 can be activated based on the propagation times of the different detection areas 2111 - 211, receive laser pulses to calculate a model of the environment 200 in the form of a point cloud.
• the control device 190 can also have an external interface 193 for communication with higher-level control devices.
• the components of the LiDAR device 110 shown in the present example are accommodated in a common housing 101, which has a window 102 that is transparent to the light radiation used in each case.
• the control device 190 or parts of the control device 190 can also be accommodated inside the housing 101 .
• FIG. 2 schematically shows a detailed view of the LiDAR device 110 of the LiDAR system 100 from FIG. 1 in a known embodiment.
• the transmission device 120 comprises only a single transmission module 121 .
• the laser beam 122 emitted by the transmission module 121 is deflected by means of a first deflection mirror 142 onto a mirror 151 of the scanning device 150 rotating about an axis 152 in the direction of the window 102 through which it leaves the housing 101 .
• the reflected light radiation 129 which enters the housing 101 of the LiDAR device 110 via the window 102, is deflected by the rotating mirror 151 of the scanning device 150 and reaches the at least one detector 131 of the receiving device 130 via a second deflection mirror 143. How already explained in connection with FIG.
• FIG. 3 schematically shows a detailed view of the LiDAR device 110 of the LiDAR system 100 from FIG. 1 in an embodiment according to the invention.
• the modified transmission device 120 now includes two transmission modules 121, 124, which serve as emitters that can be controlled independently of one another.
• the two transmission modules 121, 124 are preferably technically identical in design, so that they each emit identical laser radiation 121, 125.
• the two transmission modules 121, 124 are assigned optional optics 1611, 1612 for collimation, which are preferably also designed identically. As a result, both transmission modules 121, 124 emit electric laser beams 122, 125 which, by means of a suitable beam combination device 140, are already optimally added in the device.
• a deflection mirror 140 equipped with a passage opening 141 is used as a possible beam combination device 140 , which deflects a first of the two laser beams 122 , 125 while allowing the respective other laser beam to pass through the passage opening 124 .
• the primary light beam 122 of the primary transmission module 121 is deflected at the reversing mirror 140 in the direction of the scanning device 150, while the secondary light beam 125 of the secondary transmission module 124, which is located behind the deflection mirror 140 in the present example, passes through the passage opening 141.
• the primary light beam 122 strikes an edge region 142 as close as possible to the passage opening 141 on the deflection mirror 140 .
• the two laser beams 122, 125 are brought as close as possible to one another, so that their optical paths are already superimposed in the device and the two laser beams 122, 125 are therefore added.
• the two laser beams 122, 125 leave the LiDAR device 100 in the form of a combined laser beam 127.
• the combined laser beam 127 has light pulses 128 with a significantly increased pulse peak power. It makes sense to design the deflection mirror 140 as a large mirror with a slightly offset lateral gap (vertical passage opening). For a good addition of the laser beams 122,
• the two transmission modules 121, 125 are technically identical and have identical operating conditions, such as temperature, Experienced. Furthermore, it is necessary for the two laser beams 122, 125 to strike one another optimally in terms of space and time.
• the reception path of the LiDAR device 110 can essentially remain unchanged.
• the light radiation 129 that is reflected back is also deflected by the rotating mirror 151 onto the deflection mirror 140, which in turn deflects the light radiation 129 that is reflected back in the direction of the at least one detector 131.
• almost the entire playing surface of the deflection mirror 140 is available for deflecting the light radiation 129 that is reflected back, so that a relatively large amount of light can reach the detector 131 .
• the relatively narrow passage opening 141 does not represent any significant loss of mirror surface.
• the reflected light radiation can also be directed into the at least one detector 131 via a separate deflection mirror or another light guide.
• the laser of the two transmission modules 121, 124 serving as emitters and the associated optics and electronics (not shown here) are arranged in a stationary manner on the stator.
• the detector 121 of the receiving device 120 and the associated optics 163, 164 and electronics (not shown here) are arranged in a stationary manner on the stator. This results in well-known advantages for heat dissipation as well as energy and data transmission compared to a rotating LiDAR system.
• the installation space is not increased, or at least not significantly so. This can be realized, for example, by placing the secondary transmission module 124 in the corner behind the deflection mirror 140 .
• the number n of photons arriving in the detector 131 at a point in time t serves as the unit of the ordinate axis.
• the two light pulses 123, 126 add up to a significantly larger combined light pulse 128.
• the combined light pulse 128 has a significantly improved signal-to-noise ratio compared to the individual pulses 123, 126 due to a higher pulse peak power in its edge regions (t ⁇ ti and t>ts) due to the pulse addition.
• the primary light pulse 123 arrives at the point in time t2, while the secondary light pulse 126 arrives at a somewhat later point in time U.
• This small time offset ⁇ t leads to a broadening of the combined light pulse 128 with a simultaneous reduction in its maximum amplitude.
• These undesirable effects lead to a reduction in the accuracy of the LiDAR system 100. It is therefore necessary for the two light pulses 123, 126 to arrive in the respective target area as synchronously as possible. Possible inaccuracies in the temporal synchronization of the primary and secondary light pulses 123,
• jitter effects which also lead to a reduction in measurement accuracy, can be treated by primary and secondary pulses that tend to be slightly longer and therefore flatter peaks.
• the range of the LiDAR system 100 can be increased by temporarily switching on the secondary transmission module 124 to improve the view in any spatial angle of the observation area 210 .
• FIGS. 5 shows a first driving situation of an ego vehicle 300 equipped with the LiDAR system 100 according to the invention.
• the current observation area 210 is scanned in a relatively narrow central area 213 with a high pulse peak power achieved by switching on the secondary transmission module 124 . Due to the long range achieved in the relevant central area 213, one's own lane can be scanned for possible obstacles in advance.
• the two left and right of the central area 213 arranged areas 212, 114 with a by switching off the secondary Transmitting module 124 sampled reduced pulse peak power.
• these areas 212, 214 this results in a medium range of the LiDAR system 100 that is usually used to scan the observation area 210. Since the long ranges achieved with the help of the switched-on secondary transmission module 124 for the automated driving functions are generally only required at higher speeds and If, as expected, there are no people in the immediate vicinity 200 of the LiDAR system 100 at higher speeds, an intelligent operating mode can be provided in which the secondary transmission module 124 is only switched on at higher speeds or only above a certain speed. In this way, eye safety can be guaranteed despite the relatively high pulse peak power.
• the driving situation shown in FIG. 6, corresponds to ego vehicle 300 approaching a street crossing.
• the ego vehicle 300 can use the LiDAR system 100 to scan the crossing road for rapidly approaching vehicles.
• the secondary transmission module 124 is switched on in the lateral areas 216, 218 located at the edge of the observation area 210 in order to enable a lateral distant view of the crossing road and the objects located thereon.
• the areas 215, 217, 219 are only scanned with a medium range, which is done by switching off the secondary transmission module 124 during the scanning process of the areas 215, 217, 219 in question.
• the transmission modules can include one or more laser light sources, which are designed, for example, as edge emitters, VCSELs, VeCSELs. Such a transmission module can illuminate the observation area, for example, by means of individual spots, linearly or sequentially arranged, discrete individual source spots, line and column lighting, and area lighting (flash).
• the scanning device can comprise one or more light deflection units, in particular a macroscopic mirror which rotates about its vertical axis and has at least one reflecting surface. A front and rear reflection as well as polygon mirrors with several reflecting surfaces are also possible.
• the LiDAR system can be of various have independent features of the optical paths with, for example, spherical and cylindrical lenses, separate parallel and non-parallel beam paths and locally coincident beam paths, as well as stationary deflection mirrors and optical filters for the transmission and reception path.
• an individual detector linearly and sequentially arranged, discrete individual detectors, a 1D array or a 2D array with or without superpixel formation (macropixels), with common evaluation circuits and methods (e.g. histogram formation with SPADs) are used for detection.
• Various detector technologies such as imager, PIN, PSD, APD, SPAD or SiPM can be used.
• the detector pixels can also be activated successively in order to increase the signal-to-noise ratio of the sensor.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Computer Networks & Wireless Communication (AREA)
• General Physics & Mathematics (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• Electromagnetism (AREA)
• Optical Radar Systems And Details Thereof (AREA)

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Citations (8)

• 2021
  • 2021-04-19 DE DE102021203829.8A patent/DE102021203829A1/de active Pending
• 2022
  • 2022-04-14 WO PCT/EP2022/060057 patent/WO2022223441A1/de active Application Filing
  • 2022-04-14 CN CN202280029602.2A patent/CN117222912A/zh active Pending

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