LiDAR

Abstract

The present invention provides a laser radar, comprising a light emitting device, a polarization splitting device, a beam adjusting device, a scanning device, and a light receiving device. The light emitting device is adapted to emit a probe beam for detecting a target; the polarization splitting device is adapted to reflect the probe beam and transmit an echo beam that has undergone polarization state adjustment and focusing processing by the beam adjusting device; the beam adjusting device is adapted to perform focusing processing and polarization state adjustment on the probe beam reflected by the polarization splitting device and the echo beam reflected by the scanning device; the scanning device is adapted to reflect the probe beam that has undergone focus processing and polarization state adjustment by the beam adjusting device to scan a target and reflect the echo beam reflected by the target; and the light receiving device is adapted to receive the echo beam transmitted by the polarization splitting device. The laser radar provided by the present invention can reduce costs and size while ensuring the required detection accuracy and detection range of the laser radar.

Description

Technical Field

[0001] The present invention relates to the field of environmental perception technology, and in particular to a laser radar. Background Art

[0002] LiDAR is an important sensor for sensing information around a vehicle and is a guarantee of the safety and intelligence of cars with autonomous driving functions.

[0003] Since the lidar needs to be installed on the car and the information it detects will directly affect the safety of the vehicle's driving process, the lidar needs to meet the requirements of small size, high reliability, high imaging frame rate, high resolution, and long ranging.

[0004] In the existing technology, in order to ensure the performance of the laser radar, more optical devices are set up or more laser radars are directly set up, which makes the laser radar larger in size. Therefore, it is necessary to reasonably design the laser radar so that it can be more miniaturized while meeting the requirements of optical path transmission and detection accuracy.

[0005] Therefore, how to reduce the size of the lidar based on the requirements of lidar detection accuracy and detection distance has become a technical problem that needs to be solved urgently. Summary of the Invention

[0006] The present invention provides a laser radar, which reduces the cost and the size of the laser radar while ensuring the detection accuracy and detection distance requirements of the laser radar.

[0007] To solve the above problems, an embodiment of the present invention provides a laser radar, including a light emitting device, a polarization splitting device, a beam adjusting device, a scanning device, and a light receiving device, wherein:

[0008] The light emitting device is adapted to emit a detection light beam for detecting a target;

[0009] The polarization beam splitting device is adapted to reflect the detection beam and transmit the echo beam that has undergone polarization state adjustment and focusing processing by the beam adjustment device;

[0010] The beam adjustment device is adapted to perform focusing processing and polarization state adjustment on the detection beam reflected by the polarization splitting device and the echo beam reflected by the scanning device;

[0011] The scanning device is adapted to reflect the probe light beam that has been focused and polarization-adjusted by the light beam adjusting device to scan the target, and to reflect the echo light beam reflected by the target;

[0012] The light receiving device is adapted to receive the echo light beam transmitted by the polarization splitting device.

[0013] Optionally, the beam adjustment device includes a lens and a wave plate, wherein:

[0014] The lens is adapted to focus the probe beam reflected by the polarization splitting device and the echo beam whose polarization state is adjusted by the wave plate;

[0015] The wave plate is suitable for adjusting the polarization state of the detection light beam focused by the lens and the echo light beam reflected by the scanning device.

[0016] Optionally, the angle between the plane where the lens is located and the plane where the wave plate is located is in the range of 3°-15°.

[0017] Optionally, the scanning device is arranged at the front focus of the lens.

[0018] Optionally, the light emitting device includes a plurality of laser emitters, and the angle between the plane where the plurality of laser emitters and the detection light beam are located and the vertical plane is in a range of 0°-15°.

[0019] Optionally, it also includes:

[0020] The first reflector is adapted to reflect the detection beam having been focused and polarization-adjusted by the beam adjusting device to the scanning device, and to reflect the echo beam reflected by the scanning device to the beam adjusting device.

[0021] Optionally, the number of the light emitting device, the polarization splitting device, the light beam adjusting device, the first reflector and the light receiving device are all two, and are symmetrically arranged with respect to the scanning device.

[0022] Optionally, the angle between the plane where the detection light beams reflected by the two first reflectors to the scanning device are located and the normal line of the scanning device when the scanning device is in the initial position is in the range of 15°-25°.

[0023] Optionally, the detection beam reflected when the scanning device is in the initial position is parallel to the beam propagation plane, wherein the beam propagation plane is the plane where the beam propagation path of the detection beam is reflected by the polarization splitting device, focused by the beam adjustment device, and the polarization state is adjusted.

[0024] Optionally, it also includes:

[0025] The second reflector is adapted to reflect the detection beam reflected by the polarization splitting device to the beam adjusting device, and to reflect the echo beam focused and polarization-state-adjusted by the beam adjusting device to the polarization splitting device.

[0026] Optionally, it also includes:

[0027] The linear polarizer is adapted to polarize the detection light beam emitted by the light emitting device and then irradiate the polarization beam to the polarization splitting device.

[0028] Optionally, it also includes:

[0029] The optical fiber is suitable for adjusting the detection light beam emitted by the light emitting device and then irradiating the detection light beam to the polarization splitting device.

[0030] Optionally, it also includes:

[0031] The filter is adapted to filter the echo light beam transmitted by the polarization splitting device and then irradiate the light beam to the light receiving device.

[0032] Optionally, it also includes:

[0033] The beam expansion device is suitable for expanding the detection range of the detection light beam reflected by the scanning device and the receiving range of the echo light beam reflected by the target.

[0034] Compared with the prior art, the technical solution of the embodiment of the present invention has the following advantages:

[0035] The laser radar provided in an embodiment of the present invention includes: a light emitting device, a polarization splitting device, a beam adjusting device, a scanning device and a light receiving device. The light emitting device emits a detection beam for detecting a target. The polarization splitting device reflects the detection beam to the beam adjusting device for focusing processing and polarization state adjustment, and then irradiates the detection beam to the scanning device. The scanning device reflects the detection beam that has been focused and polarization-adjusted by the beam adjusting device to scan the target. When the detection beam is irradiated to the target, the echo beam generated by the target reflecting the detection beam is irradiated to the scanning device again. The scanning device reflects the echo beam to the beam adjusting device. The beam adjusting device further focuses and polarization-adjusts the echo beam, and then irradiates the polarization splitting device. After being transmitted by the polarization splitting device, it is irradiated to the light receiving device and received by it. It can be seen that the laser radar provided in the embodiment of the present invention, through the use of a polarization splitting device and a beam adjustment device, makes it possible for the optical device used for the propagation of the detection beam and the optical device used for the propagation of the echo beam to be the same, so that the propagation of the detection beam and the echo beam can be achieved at the same time using the same optical device, realizing a polarized coaxial optical path, reducing the optical devices used, and on the basis of ensuring the detection accuracy and detection distance requirements of the laser radar, reducing the cost and reducing the size of the laser radar.

[0036] In an optional solution, the beam adjustment device includes a lens and a wave plate. The lens is adapted to focus the probe beam reflected by the polarization splitter and the return beam whose polarization state has been adjusted by the wave plate. The wave plate is adapted to adjust the polarization state of the probe beam focused by the lens and the return beam reflected by the scanning device. Thus, during the propagation of the probe beam, the probe beam reflected by the polarization splitter is first focused by the lens and then polarized by the wave plate. This ensures that the stray beam reflected by the lens surface remains a beam that has not undergone polarization adjustment. When the stray beam strikes the polarization splitter, it does not pass through the polarization splitter. This prevents the detection accuracy from being affected by the inclusion of the stray beam reflected by the lens surface in the beam received by the light receiving device, thereby improving the accuracy of laser radar detection. Furthermore, the placement of the lens after the polarization splitter in the propagation path of the probe beam can reduce the number of components used, further reducing the size of the laser radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0038] Figure 1 1 is a structural block diagram of an optical device of a laser radar provided in an embodiment of the present invention;

[0039] Figure 2 1 is a schematic diagram of the structure of an optical device of a laser radar provided by an embodiment of the present invention and a schematic diagram of the optical path propagation of a detection beam;

[0040] Figure 3 yes Figure 2 The schematic diagram of the structure of the optical device of the laser radar and the optical path propagation diagram of the echo beam are shown;

[0041] Figure 4 1 is a schematic structural diagram of a laser radar provided by an embodiment of the present invention;

[0042] Figure 5 yes Figure 4 An exploded view of the lidar is shown;

[0043] Figure 6 is an enlarged schematic diagram of an optical fiber of a laser radar provided in an embodiment of the present invention;

[0044] Figure 7 is another structural schematic diagram of a laser radar provided by an embodiment of the present invention;

[0045] Figure 8 yes Figure 4 A partial cross-sectional schematic diagram of the lidar shown. DETAILED DESCRIPTION

[0046] To reduce the size of a laser radar, an embodiment of the present invention provides a laser radar, including a light emitting device, a polarization splitting device, a beam adjusting device, a scanning device, and a light receiving device, wherein:

[0047] The light emitting device is adapted to emit a detection light beam for detecting a target;

[0048] The polarization beam splitting device is adapted to reflect the detection beam and transmit the echo beam that has undergone polarization state adjustment and focusing processing by the beam adjustment device;

[0049] The beam adjustment device is adapted to perform focusing processing and polarization state adjustment on the detection beam reflected by the polarization splitting device and the echo beam reflected by the scanning device;

[0050] The scanning device is adapted to reflect the probe light beam that has been focused and polarization-adjusted by the light beam adjusting device to scan the target, and to reflect the echo light beam reflected by the target;

[0051] The light receiving device is adapted to receive the echo light beam transmitted by the polarization splitting device

[0052] Thus, when performing target detection, the light emitting device emits a detection beam for detecting the target, the polarization splitting device reflects the detection beam to the beam adjusting device for focusing processing and polarization state adjustment, and then irradiates it to the scanning device. The scanning device reflects the detection beam that has been focused and polarization-adjusted by the beam adjusting device to scan the target. After the detection beam is irradiated to the target, the echo beam generated by the target reflecting the detection beam is irradiated to the scanning device again. The scanning device reflects the echo beam to the beam adjusting device. The beam adjusting device further focuses and polarization-adjusts the echo beam, and then irradiates it to the polarization splitting device. After being transmitted through the polarization splitting device, it is irradiated to the light receiving device and received by it.

[0053] It can be seen that the laser radar provided in the embodiment of the present invention, through the use of a polarization splitter device, makes the optical device used for the propagation of the detection beam and the optical device used for the propagation of the echo beam the same, so that the propagation of the detection beam and the echo beam can be achieved at the same time using the same optical device, realizing a polarized coaxial optical path, reducing the optical devices used, and on the basis of ensuring the detection accuracy and detection distance requirements of the laser radar, reducing the cost and reducing the size of the laser radar.

[0054] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0055] It should be noted that the orientations or positional relationships indicated in this specification are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience and simplification of description, and do not indicate or imply that the device referred to must have a specific orientation or be constructed in a specific orientation. Therefore, it should not be understood as a limitation on the present invention.

[0056] Please refer to Figure 1-Figure 3 , Figure 1 1 is a structural block diagram of an optical device of a laser radar provided in an embodiment of the present invention; Figure 2 1 is a schematic diagram of the structure of an optical device of a laser radar provided by an embodiment of the present invention and a schematic diagram of the optical path propagation of a detection beam; Figure 3 yes Figure 2 The diagram shows the structure of the optical device of the laser radar and the optical path propagation diagram of the echo light beam.

[0057] like Figure 1-Figure 3 As shown, the laser radar provided by the embodiment of the present invention includes a light emitting device 1, a polarization spectrometer 2, a beam adjusting device 3, a scanning device 4 and a light receiving device 5, wherein: the light emitting device 1 is suitable for emitting a detection beam for detecting a target; the polarization spectrometer 2 is suitable for reflecting the detection beam, and transmitting an echo beam that has been polarization-adjusted and focused by the beam adjusting device 3; the beam adjusting device 3 is suitable for focusing and polarization-adjusting the detection beam reflected by the polarization spectrometer 2 and the echo beam reflected by the scanning device 4; the scanning device 4 is suitable for reflecting the detection beam that has been focused and polarization-adjusted by the beam adjusting device 3 to scan the target, and reflecting the echo beam reflected by the target; the light receiving device 5 is suitable for receiving the echo beam transmitted by the polarization spectrometer 2.

[0058] It should be noted that the specific positions of the light emitting device 1, polarization beam splitter 2, beam adjuster 3, scanner 4, and light receiving device 5 are not limited as long as they can ensure the transmission requirements of the light beam. Of course, in a specific embodiment, the light emitting device 1, polarization beam splitter 2, beam adjuster 3, scanner 4, and light receiving device 5 can be arranged as close as possible to reduce the size of the lidar from a structural perspective.

[0059] In addition, as long as the light beam adjusting device 3 can adjust the polarization state and focus the light beam, the number of optoelectronic devices included therein is not limited.

[0060] like Figure 4 and Figure 5 As shown, Figure 4 1 is a schematic structural diagram of a laser radar provided by an embodiment of the present invention; Figure 5 yes Figure 4 As shown in the exploded view of the laser radar, in addition to devices such as the light emitting device 1, the polarization spectrometer 2, the light beam adjustment device 3, the scanning device 4 and the light receiving device 5, the laser radar provided by the embodiment of the present invention also includes a mechanical structure 12 for installing each device (including the light emitting device 1, the polarization spectrometer 2, the light beam adjustment device 3, the scanning device 4 and the light receiving device 5), and a control device 11 for controlling and processing signals of the light emitting device 1, the light receiving device 5 and the scanning device 4. Specifically, the control device 11 can be a circuit board.

[0061] The polarization beam splitter 2 can reflect or transmit laser beams with different polarization states. This, combined with the beam adjuster 3, which adjusts the polarization states of the probe and return beams, ensures a polarized coaxial optical path. However, since the beams diverge during propagation, this divergence can affect the laser radar's range-finding capabilities. Therefore, the beam adjuster 3 also needs to have a focusing function.

[0062] Specifically, the polarization splitting device 2 can be a polarizing beam splitter (PBS) or a polarization beam splitter plate; the light emitting device 1 can be a semiconductor laser, including a vertical cavity surface emitting laser (VCSEL) or an edge emitting laser (EEL), so as to reduce costs while ensuring detection resolution.

[0063] Specifically, the scanning device 24 may be a galvanometer mirror, which rotates under the drive of the driving device, so that the detection beam scans the target in the three-dimensional space and receives the echo beam reflected by the target in the three-dimensional space.

[0064] In a specific embodiment, the light emitting device 1 may include multiple laser emitters, such as 4 or more, and the angle range between the multiple laser emitters and the plane where the detection beam is located and the vertical plane is 0°-15°, thereby improving the detection coverage and detection resolution.

[0065] It is easy to understand that the plane where multiple laser emitters and detection beams are located is the plane passing through each laser emitter, and the vertical plane is the plane parallel to the irradiation direction of the detection beams emitted by each laser emitter in the vertical plane when the laser radar is placed according to the detection position.

[0066] So, when doing environmental detection, please refer to Figure 1-Figure 3 The light transmission path shown in FIG2 is as follows: the light emitting device 1 emits a detection beam for detecting the target and irradiates the detection beam to the polarization splitting device 2. The polarization splitting device 2 transmits and reflects the light beams with different polarization states in the detection beam respectively, wherein the reflected detection beam is along Figure 1 and Figure 2 The direction of arrow A is irradiated to the beam adjustment device 3 (the transmitted part passes through the polarization splitter 2 and stops detecting the object). The beam adjustment device 3 focuses the detection beam and adjusts the polarization state, and then irradiates it to the scanning device 4. The scanning device 4 reflects it. The reflected scanning beam is irradiated to the environment to scan the target. The target reflects the detection beam, generates an echo beam and irradiates it to the scanning device 4. Please refer to Figure 1 and 3 The light path shown is propagated, and the echo light beam is irradiated to the light beam adjustment device 3 along the arrow B. The light beam adjustment device 3 focuses the echo light beam and adjusts the polarization state. In this way, the light beam reflected by the polarization splitting device 2 undergoes two polarization state adjustments, and the polarization state changes. After being irradiated to the polarization splitting device 2 again, it can be transmitted and irradiated to the light receiving device 5.

[0067] When the polarization spectrometer 2 is used for splitting, not only is part of the light beam reflected to generate a detection beam, but part of the light beam is also transmitted through the polarization spectrometer 2 along the propagation direction of the light beam. In order to reduce the influence of the transmitted light beam on the detection results of the laser radar, in a specific embodiment, a light-absorbing device or light-absorbing material can be set in the propagation path of the transmitted light beam.

[0068] In this way, the laser radar provided by the embodiment of the present invention, through the use of a polarization splitting device and a beam adjustment device, makes it possible for the optical device used for the propagation of the detection beam and the optical device used for the propagation of the echo beam to be the same, so that the propagation of the detection beam and the echo beam can be achieved at the same time using the same optical device, realizing a polarized coaxial optical path, reducing the optical devices used, and reducing costs and reducing the size of the laser radar while ensuring the laser radar environmental detection accuracy and detection distance requirements.

[0069] However, in order to facilitate the setting of the scanning device 4, realize the reasonable layout of each device, improve the structural compactness of the laser radar, and further reduce the volume of the laser radar, in another specific embodiment, the laser radar provided by the embodiment of the present invention may also include a first reflector 6, which is suitable for reflecting the detection light beam that has been focused and polarization-adjusted by the light beam adjustment device 3 to the scanning device 4, and reflecting the echo light beam reflected by the scanning device 4 to the light beam adjustment device 3.

[0070] like Figure 2-Figure 5 As shown, when the first reflector 6 is set, the scanning device 4 can be set in the space above other optical devices (light emitting device 1, polarization splitting device 2, light beam adjustment device 3 and light receiving device 5) by reasonably setting the inclination state and inclination angle of the first reflector 6, so that the space of the laser radar can be more fully utilized and the increase in the size of the laser radar caused by the various devices being set on the same plane can be avoided.

[0071] In this way, when performing target detection, the light emitting device 1 emits a detection light beam for detecting the target, which is then irradiated to the first reflector 6 after passing through the polarization spectrometer 2 and the light beam adjustment device 3, and is reflected by the first reflector 6 to the scanning device 4. The scanning device 4 further reflects it, and the reflected scanning light beam is irradiated to the environment to scan the target. The target reflects the detection light beam, generates an echo light beam and irradiates the scanning device 4. The echo light beam is irradiated to the first reflector 6 through the scanning device 4, and then reflected by the first reflector 6 to the light beam adjustment device 3, and is transmitted to the light receiving device 5 through the polarization spectrometer 2.

[0072] Of course, in order to further reduce the volume of the laser radar, in another specific embodiment, a second reflector 7 can also be set. The second reflector 7 is suitable for reflecting the detection light beam reflected by the polarization splitting device 2 to the light beam adjustment device 3, and reflecting the echo light beam focused and polarization-state adjusted by the light beam adjustment device 3 to the polarization splitting device 2.

[0073] The setting of the second reflector 7 can change the transmission direction of the detection beam and the echo beam, so that the relative position between the beam adjustment device 3 and the polarization splitting device 2 can be adjusted, so that the rationality of the setting of each device in the laser radar is improved, thereby improving the compactness of the laser radar and further reducing the volume of the laser radar.

[0074] In order to improve the quality of the light beam used for detection, in another specific embodiment, the laser radar provided by the embodiment of the present invention may also include: a linear polarizer 8, which is suitable for polarizing the detection light beam emitted by the light emitting device 1 and then irradiating it to the polarization splitting device 2.

[0075] It is easy to understand that the linear polarizer 8 first polarizes the detection beam emitted by the light emitting device 1, and the polarized detection beam is irradiated to the polarization splitter 2. Therefore, the linear polarizer 8 is arranged between the light emitting device 1 and the polarization splitter 2.

[0076] The arrangement of the linear polarizer 8 can polarize the light beam emitted by the light emitting device 1 to obtain a light beam perpendicular to the polarization angle of the linear polarizer 8 , thereby improving the quality of the detection light beam used for scanning and the detection effect.

[0077] In order to reduce the divergence angle of the detection beam, in another embodiment, as Figure 2 and Figure 6 As shown, Figure 6 It is an enlarged schematic diagram of the optical fiber of the laser radar provided in an embodiment of the present invention. The laser radar provided in an embodiment of the present invention may also include: an optical fiber 9 for adjusting the detection light beam emitted by the light emitting device 1 and then irradiating it to the polarization splitting device 2.

[0078] It is easy to understand that the optical fiber 9 can also be arranged between the light emitting device 1 and the polarization splitting device 2.

[0079] The optical fiber 9 can perform beam adjustment processing on the light beam emitted by the light emitting device 1 to reduce the divergence angle of the detection beam and improve the quality of the detection beam used for scanning and the detection effect.

[0080] Of course, in another specific embodiment, the optical fiber 9 and the linear polarizer 8 can be provided simultaneously to achieve more comprehensive processing of the detection light beam.

[0081] In order to improve the performance of the laser radar and improve the quality of the echo light beam received by the light receiving device 5, in a specific embodiment, the laser radar provided by the embodiment of the present invention may also include: a filter (not shown in the figure), which is suitable for filtering the echo light beam transmitted by the polarization splitting device 2 and then irradiating it to the light receiving device 5.

[0082] The setting of the filter can filter the light beam transmitted by the polarization beam splitting device 2, thereby reducing the influence of unnecessary light beams (stray light beams) on the detection effect.

[0083] In order to further improve the detection range of the laser radar, in a specific implementation, please refer to Figure 7 , Figure 7 This is another structural schematic diagram of the laser radar provided by an embodiment of the present invention. As shown in the figure, the laser radar provided by an embodiment of the present invention includes a beam expansion device 10, which is suitable for expanding the detection range of the detection light beam reflected by the scanning device 4 and the receiving range of the echo light beam reflected by the target.

[0084] By processing the detection beam through the beam expansion device 10, the detection range that the detection beam can illuminate is made larger, and at the same time, the echo beam reflected from the target within a larger range can be received, thereby expanding the detection range and the receiving range.

[0085] In order to improve the field of view of the laser radar, specifically, continue to refer to Figure 1The laser radar provided in an embodiment of the present invention can have two light emitting devices 1, polarization splitting devices 2, beam adjustment devices 3, first reflectors 6 and light receiving devices 5, and they can be symmetrically arranged with respect to the scanning device 4.

[0086] It should be noted that the symmetrical arrangement of the scanning device 4 described herein refers to a symmetrical arrangement of the plane formed by the horizontal and vertical directions of the center of the scanning device 4 in the direction of the laser radar detection beam, that is, Figure 1 and Figure 2 The structure shown.

[0087] In this way, the field of view of the two sets of devices can be obtained. By stitching the fields of view, a larger field of view can be obtained, thereby improving the detection range of the lidar.

[0088] Of course, when the laser radar is also provided with a linear polarizer 8, a light 9 or a filter, two linear polarizers 8, two light 9 or two filters can be provided respectively and arranged symmetrically with respect to the scanning device.

[0089] In order to ensure the effect of stitching the images corresponding to the fields of view detected by the two groups of devices, in a specific embodiment, the two first reflectors 6 of the laser radar provided in the embodiment of the present invention reflect the detection light beams of the scanning device 4 to the common plane, and the angle range with the normal of the scanning device 4 when it is in the initial position is 15°-25°.

[0090] It is easy to understand that the plane where the detection beams reflected by the two first reflectors 6 to the scanning device 4 are located refers to the plane formed by the two detection beams; the scanning device 4 is in the initial position refers to the position when the scanning device 4 is not driven to rotate.

[0091] If the angle between the plane where the detection light beams reflected by the two first reflectors 6 to the scanning device 4 are located and the normal of the scanning device 4 when the scanning device 4 is in the initial position is too large, it is easy to cause the range covered by the detection light beam to be discontinuous and the pattern after splicing to be irregular; if the angle is too small, it is easy to cause the range covered by the detection light beam to have a high degree of overlap, and interference will occur between different detection light beams, affecting the detection effect.

[0092] In order to enable the beam adjustment device 3 to realize the functions of focusing the detection beam and the echo beam and adjusting the polarization state, in a specific embodiment, please refer to Figure 8 , Figure 8 yes Figure 4The laser radar shown is a partial cross-sectional schematic diagram. The beam adjustment device 3 of the laser radar provided in this embodiment of the present invention may include a lens 31 and a wave plate 32, wherein the lens 31 is adapted to focus the probe beam reflected by the polarization splitting device 2 and the echo beam whose polarization state has been adjusted by the wave plate 32; and the wave plate 32 is adapted to adjust the polarization state of the probe beam focused by the lens 31 and the echo beam reflected by the scanning device 4.

[0093] On the propagation path of the detection beam, the lens 31 is located in front of the wave plate 32 , and on the propagation path of the echo beam, the lens 31 is located behind the wave plate 32 .

[0094] In a specific embodiment, the wave plate 32 can be a 1 / 4 wave plate, so that the polarization direction of the light beam reflected by the polarization splitter 2 changes after passing through the wave plate 32, and is transmitted to the light receiving device 5 after being irradiated by the polarization splitter 2.

[0095] In a specific embodiment, the lens 31 and the wave plate 32 can be set in a common mounting seat for the two, and by setting a spacer ring between the two, the two can be fixed, and the adaptability of 31 and the wave plate 32 to the environment can be improved, the risk of breakage can be reduced, and reliability can be improved.

[0096] It is easy to understand that in addition to having the function of focusing the light beam or adjusting the polarization state, each optical device such as the lens 31 and the wave plate 32 inevitably has the function of reflecting the light beam on its surface. On the propagation path of the detection light beam, the surface of the lens 31 reflects the light beam to generate a first stray light beam, and the reflected light beam is irradiated to the polarization spectrometer 2. However, since the lens 31 is located in front of the wave plate 32, the first stray light beam does not pass through the wave plate 32 for adjusting the polarization state. The reflected light beam irradiated to the polarization spectrometer 2 will not be transmitted from the polarization spectrometer 2 and will not affect the light beam received by the light receiving device 5.

[0097] In this way, during the propagation of the detection beam, the detection beam reflected by the polarization spectrometer 2 is first focused by the lens 31, and then adjusted in polarization state by the wave plate 32, so that the stray beam reflected by the surface of the lens 32 is still a beam that has not been adjusted in polarization state. When the stray beam is irradiated by the polarization spectrometer 2, it will not be transmitted from the polarization spectrometer 2, thereby not affecting the detection accuracy due to the inclusion of the stray beam reflected by the surface of the lens 31 in the beam received by the light receiving device 5, thereby improving the accuracy of the lidar detection.

[0098] However, it is easy to understand that in order to further reduce the generation of stray light beams in the laser radar and avoid the detection light beam after the polarization state is changed from being reflected by the surface of the wave plate 32 and being received by the light receiving device 5 through the polarization splitter 2, thereby affecting the detection accuracy of the laser radar, in a specific embodiment, there is a certain angle between the plane where the lens 31 of the laser radar provided by the embodiment of the present invention is located and the plane where the wave plate 32 is located. In this way, the stray light beam generated by the reflection of the detection light beam after the polarization state is changed on the surface of the wave plate 32 will be deflected by a certain angle, and the deflected stray light beam will not return along the original transmission path of the detection light beam, and thus will not be received by the light receiving device 5.

[0099] The angle between the plane where the laser radar lens 31 is located and the plane where the wave plate 32 is located can be set. For this purpose, the angle range can be set to 3°-15°. For the above angle range, when the angle is too large, the optical path volume will increase. When the angle is too small, it will not play a role in reducing stray light.

[0100] It should be noted that the angle between the plane where the lens 31 is located and the plane where the wave plate 32 is located described in this article refers to the angle between the two planes in space, where both the plane where the lens 31 is located and the plane where the wave plate 32 is located are perpendicular to the base of the laser radar.

[0101] In order to further improve the accuracy of lidar detection, the distance between the polarization spectrometer 2 and the light emitting device 1, as well as the distance between the polarization spectrometer 2 and the light receiving device 5 can be shortened. In a specific embodiment, a lens is not required between the light emitting device 1 and the polarization spectrometer 2 in the propagation path of the detection light beam, and a lens is not required between the light receiving device 5 and the polarization spectrometer 2 in the propagation path of the echo light beam. That is, the number of lenses along the propagation path of the detection light beam or the echo light beam is 1.

[0102] In this way, on the one hand, since no lens is required between the light emitting device 1 and the polarization spectrometer 2, the distance between the light emitting device 1 and the polarization spectrometer 2 is relatively close, thereby improving the alignment reliability of the polarization spectrometer 2 and the light emitting device 1. At the same time, no lens is required between the light receiving device 5 and the polarization spectrometer 2, and the distance between the light receiving device 5 and the polarization spectrometer 2 can be shortened, thereby improving the alignment reliability of the polarization spectrometer 2 and the light receiving device 5, thereby improving the detection accuracy. On the other hand, along the propagation path of the detection light beam or the echo light beam, the number of lenses is 1, and on the basis of ensuring the light beam propagation requirements for the light beam, the number of optical devices used can be reduced, thereby shortening the light path and further improving the detection accuracy.

[0103] In addition, it should be noted that other optical devices, such as the aforementioned linear polarizer 8, optical fiber 9, and filter, can be arranged between the polarization spectrometer 2 and the light emitting device 1, and between the light receiving device 5 and the polarization spectrometer 2. Even if the number of lenses is reduced, the alignment reliability and the detection accuracy of the laser radar can still be improved.

[0104] However, when the light emitting device 1 includes multiple laser emitters, the detection light beams emitted by each laser emitter do not overlap due to the influence of the setting position of each laser emitter, so that the detection light beams emitted by each laser emitter cannot all be irradiated to the center of the scanning device 4 after passing through the beam adjustment device 3, resulting in reduced detection accuracy. For this reason, in a specific embodiment, the scanning device 4 is set at the front focus of the lens 31.

[0105] It is easy to understand that the front focus of the lens 31 mentioned herein refers to the point where the detection light beam converges after being irradiated to the lens 31. Figure 1 As shown in , when the scanning device 4 is set above the lens 31, the front focus of the lens 31 can be located above the lens 31, that is, as the detection light beam propagates after passing through the lens 31, it passes through the first reflector 6, changes the transmission direction, and forms a convergence point above the lens 31 in the transmission light path after passing through the first reflector 6, that is, the front focus is located above the lens 31. When setting up the scanning device 4, the scanning device 4 is set at the corresponding position.

[0106] By setting the scanning device 4 at the front focus of the lens 31, a telecentric optical path is formed between the scanning device 4 and the lens 31. The detection beam emitted by each laser emitter can be irradiated to the center of the scanning device 4 after passing through the lens 31, thereby improving the detection accuracy of the laser radar.

[0107] In another specific embodiment, in order to facilitate the design and control of the detection range, the laser radar proposed in the embodiment of the present invention can make the detection light beam reflected by the scanning device 4 in the initial position parallel to the light beam propagation plane, wherein the light beam propagation plane is the plane where the light beam propagation path of the detection light beam is reflected by the polarization splitting device 2, focused by the light beam adjustment device 3 and the polarization state adjusted.

[0108] In this way, the accuracy of controlling the scanning angle of the scanning device can be improved, and the detection accuracy of the laser radar can be improved.

[0109] Although the embodiments of the present invention are disclosed above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A laser radar, characterized in that: It includes a light emitting device, a polarization splitting device, a light beam adjusting device, a scanning device, a light receiving device and a first reflector, wherein: The light emitting device is adapted to emit a detection light beam for detecting a target; The polarization beam splitting device is adapted to reflect the detection beam and transmit the echo beam that has undergone polarization state adjustment and focusing processing by the beam adjustment device; The beam adjustment device is adapted to perform focusing processing and polarization state adjustment on the detection beam reflected by the polarization splitting device and the echo beam reflected by the scanning device; The scanning device is adapted to reflect the probe light beam that has been focused and polarization-adjusted by the light beam adjusting device to scan the target, and to reflect the echo light beam reflected by the target; The light receiving device is adapted to receive the echo light beam transmitted by the polarization splitting device; The first reflector is adapted to reflect the probe beam, which has been focused and polarization-adjusted by the beam adjusting device, to the scanning device, and to reflect the echo beam reflected by the scanning device to the beam adjusting device; in, The number of the light emitting device, the polarization beam splitting device, the beam adjusting device, the first reflector, and the light receiving device are all two, and they are symmetrically arranged with respect to the scanning device; the angle between the plane where the detection beams reflected by the two first reflectors to the scanning device are common and the normal to the scanning device when the scanning device is in the initial position is in the range of 15°-25°; The light emitting device includes a plurality of laser emitters, and the angle between the plane where the plurality of laser emitters and the detection light beam are located and the vertical plane is in a range of 0°-15°.

2. The laser radar according to claim 1, wherein The beam adjustment device includes a lens and a wave plate, wherein: The lens is adapted to focus the probe beam reflected by the polarization splitting device and the echo beam whose polarization state is adjusted by the wave plate; The wave plate is suitable for adjusting the polarization state of the detection light beam focused by the lens and the echo light beam reflected by the scanning device.

3. The laser radar according to claim 2, wherein: The angle between the plane where the lens is located and the plane where the wave plate is located is in the range of 3°-15°.

4. The laser radar according to claim 2, wherein The scanning device is arranged at the front focus of the lens.

5. The laser radar according to any one of claims 1 to 4, characterized in that: The detection light beam reflected when the scanning device is in the initial position is parallel to the light beam propagation plane, wherein the light beam propagation plane is the plane where the light beam propagation path of the detection light beam after being reflected by the polarization splitting device, focused by the light beam adjustment device, and polarization state adjusted is located.

6. The laser radar according to any one of claims 1 to 4, characterized in that: Also includes: The second reflector is adapted to reflect the detection beam reflected by the polarization splitting device to the beam adjusting device, and to reflect the echo beam focused and polarization-state-adjusted by the beam adjusting device to the polarization splitting device.

7. The laser radar according to any one of claims 1 to 4, characterized in that: Also includes: The linear polarizer is adapted to polarize the detection light beam emitted by the light emitting device and then irradiate the polarization beam to the polarization splitting device.

8. The laser radar according to any one of claims 1 to 4, wherein: Also includes: The optical fiber is suitable for adjusting the detection light beam emitted by the light emitting device and then irradiating the detection light beam to the polarization splitting device.

9. The laser radar according to any one of claims 1 to 4, characterized in that: Also includes: The filter is adapted to filter the echo light beam transmitted by the polarization splitting device and then irradiate the light beam to the light receiving device.

10. The laser radar according to any one of claims 1 to 4, characterized in that: Also includes: The beam expansion device is suitable for expanding the detection range of the detection light beam reflected by the scanning device and the receiving range of the echo light beam reflected by the target.

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