Rotating mirror unit for laser radar, corresponding laser radar and use method

Abstract

The present invention discloses a rotating mirror unit suitable for laser radar (LiDAR). The unit comprises a multi-faceted rotating mirror portion having an even number of reflective surfaces arranged in a polygonal shape, configured to change the angle of a light beam incident thereon; and a motor configured to drive the multi-faceted rotating mirror portion to rotate about its axis. Each reflective surface comprises an upper portion and a lower portion separated by a light-isolating region. The embodiments of the present invention reduce the height and size of a rotating mirror-type LiDAR, and enhance and improve its scanning accuracy and quality.

Description

Technical Field

[0001] The present disclosure relates to the field of radar, and in particular to a rotating mirror unit for a laser radar, a corresponding laser radar, and a method of use. Background Art

[0002] LiDAR (LiDAR) is a radar system that uses laser beams to detect target position, velocity, and other characteristics. It is an advanced detection method that combines laser technology with photoelectric detection technology. Due to its high resolution, good concealment, strong resistance to active interference, excellent low-altitude detection performance, small size, and light weight, LiDAR is widely used in unmanned driving, drones, intelligent robots, transportation and communications, energy security monitoring, resource exploration, and other fields. With the rapid development of autonomous driving technology in recent years, LiDAR has become indispensable as a core sensor for distance perception in the autonomous driving field.

[0003] In the field of autonomous driving, automotive LiDAR, known as the "eyes" of autonomous vehicles, is one of the most important sensors and plays a crucial role in ensuring driving safety. LiDAR uses multiple laser pulses that rotate around an axis at a specific angle to measure distance to the surrounding environment. Combined with software, it creates a point cloud map, providing the autonomous vehicle with sufficient environmental information.

[0004] Rotating-mirror automotive LiDARs are typically installed at the front or side of a vehicle. However, the scanning lines of traditional rotating-mirror automotive LiDARs are sparse, resulting in low scanning accuracy and quality. In the development of LiDAR technology, reducing the size of LiDARs while improving their scanning accuracy has always been a pressing issue.

[0005] The contents of the background technology section are merely the technologies known to the inventors and do not necessarily represent the existing technologies in this field. Summary of the Invention

[0006] The rotating mirror laser radar of the present invention reduces its volume by placing the motor inside the polygonal space surrounded by the multi-faceted rotating mirror, and encrypts the scanning lines by setting corresponding angles for the multi-faceted rotating mirror, thereby solving the problems of the laser radar in the prior art such as the large volume due to its high height and the poor scanning quality of the laser radar.

[0007] To solve the above technical problems, an embodiment of the present invention provides a rotating mirror unit suitable for a laser radar, comprising:

[0008] a multi-faceted rotating mirror portion, the multi-faceted rotating mirror portion having an even number of reflecting surfaces forming a polygon, for changing the angle of a light beam incident thereon, the multi-faceted rotating mirror portion having an axis and being rotatable about the axis;

[0009] a motor configured to drive the polygonal mirror portion to rotate around the axis;

[0010] Each of the reflecting surfaces includes an upper portion and a lower portion separated by a light-isolating area.

[0011] According to one aspect of the present invention, the motor is contained in a polygonal space surrounded by the reflecting surface.

[0012] According to one aspect of the present invention, the multi-faceted rotating mirror portion further includes a rotating mirror frame for accommodating the even number of reflecting surfaces, and the rotating mirror frame is in contact with the rotor of the motor and is driven by the rotor of the motor.

[0013] According to one aspect of the present invention, the motor includes a main shaft, and the rotating mirror frame is connected to the main shaft through at least one bearing portion.

[0014] According to one aspect of the present invention, the at least one bearing portion includes an upper bearing portion and a lower bearing portion, and the upper bearing portion and the lower bearing portion are used to connect the rotating mirror frame of the polygonal rotating mirror portion at the upper and lower parts of the main shaft respectively.

[0015] According to one aspect of the present invention, the multi-faceted mirror portion is a regular polygon, wherein the angles between two opposing reflecting surfaces and the bottom surface are the same, and the angles between two adjacent reflecting surfaces and the bottom surface are different.

[0016] According to one aspect of the present invention, the multi-faceted rotating mirror portion is a four-faceted rotating mirror, wherein the angles between two opposing reflecting surfaces and the bottom surface are the same, and the absolute values of the angles between two adjacent reflecting surfaces and the bottom surface are the same but have opposite signs.

[0017] According to one aspect of the present invention, the included angle between two of the reflecting surfaces and the bottom surface is 90.09°, and the included angle between the other two reflecting surfaces and the bottom surface is 89.91°.

[0018] According to one aspect of the present invention, the rotating mirror unit further includes a light-isolating plate and / or a light-isolating coating arranged in the light-isolating area.

[0019] The present invention also relates to a laser radar, comprising:

[0020] The rotating mirror unit according to any one of the above items, wherein the multi-faceted rotating mirror portion of the rotating mirror unit rotates around its axis;

[0021] an emitting unit, the emitting unit being configured to emit a detection laser beam for detecting a target object, the detection laser beam being emitted after being reflected by an upper portion or a lower portion of one of the reflection surfaces of the rotating mirror unit;

[0022] A receiving unit is configured to receive an echo of the detection laser beam after being reflected on a target object and convert it into an electrical signal. The echo is received by the receiving unit after being reflected by the lower part or the upper part of one of the reflecting surfaces of the rotating mirror unit.

[0023] According to one aspect of the present invention, the emitting unit includes a laser emitting module, a first folding reflector and an emitting lens group; wherein, the laser emitting module is configured to emit laser, and the laser passes through the first folding reflector and the emitting lens group in sequence and then is emitted to the upper or lower part of any reflecting surface of the rotating mirror unit.

[0024] According to one aspect of the present invention, the emitting unit further includes a reinforcing cylindrical lens. After being emitted from the emitting lens group, the laser passes through the reinforcing cylindrical lens and is then emitted to the rotating mirror unit.

[0025] According to one aspect of the present invention, the receiving unit includes a receiving lens group, a second folding reflector and a signal receiving board. The signal receiving board is configured to be position-adjustable. After the echo is reflected by the lower or upper part of any reflecting surface of the rotating mirror unit, it passes through the receiving lens group and the second folding reflector in sequence, and then is incident on the signal receiving board.

[0026] According to one aspect of the present invention, the transmitting lens group and / or receiving lens group includes a lens barrel and a lens arranged in the lens barrel, the edge of the lens barrel has a partial trimming structure, and a light blocking plate is arranged in the lens barrel.

[0027] According to one aspect of the present invention, the multifaceted mirror portion of the rotating mirror unit is a regular polygonal multifaceted mirror portion, wherein the circumscribed circle radius of the regular polygon is R, the distance between the transmitting lens along its optical axis and the rotation axis of the multifaceted mirror portion is 1.5R, the distance between the receiving lens along its optical axis and the rotation axis of the multifaceted mirror portion is 1.5R, the distance between the optical axis of the transmitting lens and the rotation axis of the multifaceted mirror portion in a direction perpendicular to the optical axis is 0.6R; the distance between the optical axis of the receiving lens and the rotation axis of the multifaceted mirror portion in a direction perpendicular to the optical axis is 0.5R.

[0028] According to one aspect of the present invention, the receiving unit is located above the transmitting unit.

[0029] According to one aspect of the present invention, the receiving unit is located below the transmitting unit.

[0030] The present invention also relates to a method for using a laser radar, which uses the laser radar as described above for detection.

[0031] In the above embodiment, the volume of the rotating mirror laser radar is reduced by compressing the overall height of the laser radar, making the laser radar smaller and more compact in structure; and the inclination angle of the mirror can increase the number of outgoing scanning lines without increasing the transmitting unit, thereby encrypting the number of lines in at least part of the scanning area and improving the scanning efficiency; and by increasing the light isolation area, mutual interference between the outgoing and incident light beams is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings, which constitute part of this disclosure, are used to provide a further understanding of the disclosure. The exemplary embodiments of the disclosure and their descriptions are used to explain the disclosure and do not constitute an improper limitation of the disclosure. In the accompanying drawings:

[0033] Figure 1A shows a schematic diagram of a rotating mirror unit according to one embodiment of the present invention;

[0034] Figure 1B shows a cross-sectional view of the rotating mirror unit along the cutting plane NN in FIG1 ;

[0035] Figure 2 A schematic diagram of a rotating mirror frame according to a preferred embodiment of the present invention is shown;

[0036] Figure 3 A block diagram of a laser radar according to an embodiment of the present invention is shown;

[0037] Figure 4 FIG2 shows an external structural diagram of a laser radar according to an embodiment of the present invention;

[0038] Figure 5 Shown Figure 4 The shown laser radar is a top view cross-section along the cutting plane NN;

[0039] Figure 6 Shown Figure 4 A cross-sectional view of the laser radar shown along the cutting plane PP;

[0040] Figure 7 shows a structural diagram of an emission lens assembly according to one embodiment of the present invention;

[0041] Figure 8 Shown Figure 4 A cross-sectional view of the laser radar shown along the cutting plane OO;

[0042] Figure 9 shows a structural diagram of a receiving lens assembly according to one embodiment of the present invention;

[0043] Figure 10A A schematic diagram showing the relative positional relationship between the transmitting and receiving lens groups and the multi-faceted rotating mirror portion according to an embodiment of the present invention; and

[0044] Figure 10B Shown Figure 10A A schematic diagram of the vertical scale of the multi-faceted rotating mirror portion.

[0045] List of reference numerals:

[0046] Reference numerals name Reference numerals name 100 Rotating mirror unit 110 Multi-faceted rotating mirror 111 reflective surface 111U Upper reflective surface 111L Lower part of reflective surface 120 motor 121 stator 122 rotor AX axis 130 Rotating mirror frame 130-1 Left mirror surface 130-2 The right mirror surface 140 spindle 151 Upper bearing 152 Lower bearing 160 light barrier 170 Motor drive circuit 180 Nut 190 Code disk 191 Photoelectric encoder 200 Transmitter unit 210 Laser emission module 211 Signal transmitting element 212 L-shaped bracket 220 First folding reflector 230 Emitting lens group 231 lens barrel 232 light barrier 233 Spacer 234 Pressing ring 235 Partial trimming structure 240 reinforced cylindrical lens 300 Receiving unit 310 Receiving lens group 311 lens barrel 312 light barrier 313 Spacer 314 Pressing ring 315 Partial trimming structure 320 Second folding reflector 330 Signal receiving board L1 Detection laser beam L1’ echo 400 LiDAR 410 Top cover 420 Windows 430 base DETAILED DESCRIPTION

[0047] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and description are to be considered as illustrative in nature and not restrictive.

[0048] In the description of the present invention, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," "clockwise," "counterclockwise," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for the purpose of facilitating the description of the present invention and simplifying the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of the aforementioned features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0049] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, removable, or integral connections; mechanical, electrical, or intercommunication connections; direct or indirect connections through an intermediary; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0050] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may also include the first and second features not being in direct contact but being in contact via another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or diagonally above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or diagonally below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0051] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0052] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0053] An embodiment of the present invention proposes a rotating mirror vehicle-mounted laser radar. By adjusting the structure of the rotating mirror laser radar, its overall height is compressed, and the scanning lines in some areas are encrypted, thereby solving the problems of large size, low scanning accuracy and low scanning quality of the laser radar.

[0054] Figure 1A 1 shows a perspective view of a rotating mirror unit 100 according to an embodiment of the present invention, Figure 1B FIG1 shows a cross-sectional view of the rotating mirror unit 100 along the cutting plane NN in FIG1 . Figure 1A and 1B As shown, the rotating mirror unit 100 includes a multi-faceted rotating mirror portion 110 and a motor 120. The multi-faceted rotating mirror portion 110 has an even number of reflecting surfaces 111 formed in a polygonal shape, for changing the angle of a light beam incident thereon, wherein each reflecting surface 111 includes an upper portion 111U and a lower portion 111L separated by a light isolation region. Figure 1AThe figure schematically shows that the multi-faceted mirror portion 110 has four reflecting surfaces 111, which form a square. It is easy for those skilled in the art to understand that the present invention is not limited to this. The number of reflecting surfaces 111 can be 6, 8 or more. In addition, the polygon can be a regular polygon or an irregular polygon, which is within the scope of the present invention. Figure 1A and 1B As shown in FIG, the polygonal mirror portion 110 includes a light-isolating plate 160 for forming a light-isolating region, thereby separating the reflective surface 111 into an upper portion 111U and a lower portion 111L, thereby preventing or reducing light crosstalk between the upper and lower portions. In addition to or in place of the light-isolating plate 160, the polygonal mirror portion 110 includes a light-isolating coating for forming a light-isolating region between the upper portion 111U and the lower portion 111L.

[0055] like Figure 1B As shown, the motor 120 includes a stator 121 and a rotor 122, and is configured to drive the polygon mirror unit 110 to rotate around the axis AX of the polygon mirror unit 110. The stator 121 may include a coil, and the rotor 122 may include a permanent magnet. When the coil is energized and a changing magnetic field is generated, the electromagnetic force drives the rotor 122 to rotate around the axis AX. Figure 1B It can be seen that the motor 120 is, for example, contained in the polygonal space surrounded by the multiple reflective surfaces 111, and is used to drive the multi-faceted rotating mirror part 110 to rotate. In addition, through such an arrangement, the height of the rotating mirror unit 100 is basically the same as the reflective surface 111, so the height of the rotating mirror unit 100 can be effectively reduced, thereby reducing the overall volume of the laser radar, making the laser radar smaller and more compact in structure. The multi-faceted rotating mirror part 110 can rotate 360 degrees at a uniform speed around its axis AX, or it can swing back and forth within a certain range. In addition, its movement speed can also be non-uniform, but follows a preset motion curve. The rotating mirror unit 100 also includes a motor drive circuit 170, which is coupled to the motor 120 and is used to control the rotation of the motor 120.

[0056] like Figure 2 As shown, according to one embodiment of the present invention, the multi-faceted rotating mirror portion 110 further includes a rotating mirror frame 130 for accommodating the even number of reflective surfaces. As shown in the figure, the rotating mirror frame 130 is also configured as a multi-faceted support having the same even number of side surfaces according to the multi-faceted rotating mirror portion 110. A reflective mirror surface is attached to each side surface of the rotating mirror frame 130, thereby forming the multiple reflective surfaces of the multi-faceted rotating mirror portion 110. The rotating mirror frame 130, for example, has a circular inner circumference, is attached and fixed to the rotor 122 of the motor, and is driven by the rotor 122 of the motor. The rotating mirror frame 130 constitutes the main body of the multi-faceted rotating mirror portion 110, and reflective surfaces are attached to the side surfaces of the rotating mirror frame 130 to form the reflective surfaces 111.

[0057] like Figure 1B As shown, the rotating mirror unit 100 further includes a main shaft 140. The main shaft 140 extends along the axis AX of the polygonal rotating mirror portion 110. The rotating mirror frame 130 is connected to the main shaft 140 via at least one bearing and is supported by the main shaft 140. When the motor drive circuit 170 drives the motor rotor 122 to rotate, the rotor 122 drives the rotating mirror frame 130 to rotate around the main shaft 140 along with the rotor 122. Figure 1B It is shown in the figure that the at least one bearing portion includes an upper bearing portion 151 and a lower bearing portion 152. The upper bearing portion 151 and the lower bearing portion 152 are respectively used to connect the rotating mirror frame 130 of the multi-faceted rotating mirror portion 110 at the upper and lower parts of the main shaft 140, so that the multi-faceted rotating mirror portion 110 and the rotating mirror frame 130 can rotate around the main shaft 140.

[0058] like Figure 1A As shown, the light-isolating plate 160 rotates with the multi-faceted rotating mirror portion 110, separating each of the multiple reflective surfaces into an upper portion 111U and a lower portion 111L. When used in a laser radar, the separated upper and lower portions are used to transmit the laser radar's detection beam or receive the laser radar's echo, respectively. The rotating mirror unit 100 also includes an end nut 180 and a code disk 190. The end nut 180 is used to secure the upper bearing portion 151, thereby securing the rotating mirror unit 100. The code disk 190 is located below the rotating mirror frame 130 and is configured to rotate with the motor's rotor 122, thereby being used to measure the angular position of the multi-faceted rotating mirror portion 110. The code disk 190, for example, has an annular code track with regularly distributed holes. When used in conjunction with a photoelectric encoder, relatively accurate angle information is provided through the periodic changes in the transmissive / non-transmissive areas of the code track region.

[0059] According to a preferred embodiment of the present invention, the laser emission module includes a plurality of laser emitters, wherein at least some of the laser emitters are arranged sequentially in the vertical direction, wherein the angle between the reflecting surface of the multi-faceted rotating mirror portion and the rotating axis can be determined according to the arrangement interval of the laser emitters in the vertical direction.

[0060] Specifically, the inclination angle between the reflective surface and the rotation axis of the polygonal mirror portion can be determined based on the light beam emission angles corresponding to two adjacent laser emitters and the target resolution that is desired to be achieved within a certain field of view.

[0061] like Figure 1AAs shown, according to a preferred embodiment of the present invention, the multi-faceted rotating mirror unit 110 is a four-faceted rotating mirror, wherein two opposing reflecting surfaces have the same angle with the principal axis AX, and the angles between two adjacent reflecting surfaces and the bottom surface have the same absolute value but opposite signs. Furthermore, the vertical spacing between two adjacent laser emitters in the laser emission module can correspond to a beam emission angle of approximately 0.5°, and a scanning target with a resolution of 0.25° can be achieved within a vertical field of view of approximately 90°. Therefore, the inclination angle between the reflecting surface and the rotating axis is set to ±0.09°.

[0062] More preferably, among the multiple laser emitters in the laser emission module, the spacing between the laser emitters in the middle part is smaller, and the spacing between the laser emitters on both sides is larger.

[0063] According to a preferred embodiment of the present invention, referring to Figure 2 .like Figure 2 In a preferred embodiment shown in FIG. 1 , two adjacent rotating mirror surfaces are shown, namely, the left rotating mirror surface 130-1 and the right rotating mirror surface 130-2. The angle between the left rotating mirror surface 130-1 (and the rotating mirror surface opposite thereto) and the bottom surface of the rotating mirror frame 130 is The angle between the right mirror surface 130-2 (and the mirror surface opposite thereto) and the bottom surface of the mirror frame 130 is 89.91°. The angle between the rotating mirror surface and the bottom surface is 90.09° (in the present invention, the angle between the rotating mirror surface and the bottom surface is expressed as the angle between the rotating mirror surface and the bottom surface outside the multi-faceted rotating mirror portion). According to this embodiment, the scanning line obtained by using a rotating mirror with an angle of ±0.09° has an average vertical angular resolution of, for example, 0.33°, a central field of view resolution of 0.25°, and a worst-case edge resolution of 0.44°.

[0064] Preferably, the precision of the angle between the rotating mirror surface and the principal axis is ±0.009°. Continuing with the aforementioned embodiment, the actual angle between the left rotating mirror surface 130-1 and the bottom surface of the rotating mirror frame 130 can be between 89.901° and 89.919°; the actual angle between the right rotating mirror surface 130-2 and the bottom surface of the rotating mirror frame 130 can be between 90.081° and 90.099°.

[0065] In this way, every time the polygonal mirror unit 110 rotates 90 degrees around the main axis 140, two adjacent reflective surfaces of the four-sided mirror cause the scanning area of the laser radar transceiver unit to shift vertically. When the scanning area is obtained by splicing the two adjacent reflective surfaces of the mirrors, a scanned image with encrypted scan lines in the vertical direction is obtained. This achieves encrypted scan lines in a partial area without adding additional transmitting units, thereby improving scanning efficiency.

[0066] Those skilled in the art will appreciate that when a hexagonal, octagonal or more polygonal rotating mirror is used in this solution, similarly, the angles between the two opposing reflective surfaces and the bottom surface are the same, and the angles between the two adjacent reflective surfaces and the bottom surface are different.

[0067] More preferably, those skilled in the art can determine the angle difference between adjacent mirror surfaces according to actual conditions and needs.

[0068] For example, a hexagonal rotating mirror has three pairs of rotating mirror surfaces, wherein one pair is set at an angle of 0.09° relative to the main axis AX, one pair is set at an angle of 0° relative to the main axis AX, and one pair is set at an angle of -0.09° relative to the main axis AX.

[0069] The present invention also relates to a laser radar comprising the rotating mirror unit 100. Figure 3 A block diagram of a laser radar according to an embodiment of the present invention is shown. As shown in the figure, the laser radar 400 includes a rotating mirror unit 100, a transmitting unit 200, and a receiving unit 300. The multi-faceted rotating mirror portion 110 of the rotating mirror unit 100 rotates around its main axis 140. The transmitting unit 200 is configured to transmit a detection laser beam L1 for detecting a target object OB. The detection laser beam L1 is reflected by the upper or lower portion of one of the reflecting surfaces of the rotating mirror unit 100 and then emitted to the detection target object OB. After diffuse reflection by the detection target OB, the receiving unit 300 is configured to receive an echo L1' of the detection laser beam L1 after being reflected by the target object OB and convert it into an electrical signal. The echo L1' is then received by the receiving unit 300 after being reflected by the lower or upper portion of one of the reflecting surfaces of the rotating mirror unit 100.

[0070] Figure 4 FIG4 shows the external structure of the laser radar 400. As shown in the figure, the laser radar 400 is in the shape of a rectangular parallelepiped, and the rotating mirror unit 100, the transmitting unit 200 and the receiving unit 300 are placed inside the laser radar 400 (as shown in FIG4). Figure 5 The laser radar 400 further includes a top cover 410, a window 420, and a base 430. The top cover 410 is used to seal the internal components of the laser radar 400. The window 420 provides a detection window through which the laser beams and laser beam echoes of the transmitting unit 200 and the receiving unit 300 can be emitted and received, respectively. The base 430 is the foundation of the laser radar 400 and is used to support the internal components of the laser radar 400.

[0071] More preferably, the base 430 can be used to install the laser radar 400 on a vehicle, such as on the vehicle roof or the front grille. Figures 5 to 9 The internal structure of the laser radar 400 is described in detail.

[0072] Figure 5 Indicated to Figure 4 The laser radar 400 is shown as a top cross-sectional view along the cutting plane NN; Figure 6 Indicated to Figure 4 The laser radar 400 is shown as a top cross-sectional view along the cutting plane PP; Figure 8 Indicated to Figure 4 The laser radar 400 shown is a top view cross-sectional view along the cutting plane OO.

[0073] Figures 5 to 9 The diagram illustrates a preferred embodiment in which the transmitting unit 200 and the receiving unit 300 are arranged vertically up and down, with the transmitting unit 200 being located below the receiving unit 300 .

[0074] like Figure 5 As shown, the interior of the laser radar 400 is roughly divided into two areas. The area on the left side of the figure houses the rotating mirror unit 100, and the area on the right side of the figure houses the transmitting unit 200 and the receiving unit 300, respectively. The receiving unit 300 and the transmitting unit 200 are arranged one above the other. Those skilled in the art will understand that the relative positions of the receiving unit 300 and the transmitting unit 200 can be interchanged and adjusted as needed, for example, with the receiving unit 300 at the bottom and the transmitting unit 200 at the top, etc., and this will not be repeated here.

[0075] Figure 6 and Figure 8 The transmitting unit 200 and the receiving unit 300 are more clearly shown in FIG. According to a preferred embodiment of the present invention, the receiving unit 300 is located above the transmitting unit 200 in a direction perpendicular to the base 430. Correspondingly, the lower portion of each reflecting surface of the multifaceted mirror portion 110 is used to receive and emit the detection laser beam of the laser radar, and the upper portion of each reflecting surface is used to receive and reflect the echo from outside the laser radar. The present invention is not limited to this. The receiving unit 300 can also be located below the transmitting unit 200, and the upper portion of each reflecting surface of the multifaceted mirror portion 110 is used to receive and emit the detection laser beam of the laser radar, and the lower portion of each reflecting surface is used to receive and reflect the echo from outside the laser radar.

[0076] like Figure 6As shown, the transmitting unit 200 includes a laser transmitting module 210, a first folding reflector 220 and a transmitting lens group 230, wherein the first folding reflector 220 is located downstream of the optical path of the laser transmitting module 210, and the transmitting lens group 230 is located downstream of the optical path of the first folding reflector 220. A signal transmitting element (such as a laser) 211 is provided on the laser transmitting module 210. The transmitting lens group 230 uses, for example, a telecentric lens group, and the telecentric lens group can optionally use three Gaussian lenses. The signal transmitting element 211 emits laser light, and the laser light passes through the first folding reflector 220 and the transmitting lens group 230 in sequence and then emerges to the lower part of any reflecting surface of the rotating mirror unit 100. Preferably, the transmitting lens group 230 is set to be adjustable along the optical axis so that its rear focal plane coincides with the signal transmitting element 211.

[0077] According to a preferred embodiment of the present invention, the transmitting unit 200 may further include, for example, a reinforcing cylindrical lens 240. The reinforcing cylindrical lens 240 is disposed downstream of the optical path of the transmitting lens group 230 and is used for short-range light reinforcement. After emitting from the transmitting lens group 230, the laser passes through the reinforcing cylindrical lens 240 and is then emitted to the lower portion of the rotating mirror unit 100, from which it is emitted into the surrounding environment. By using the reinforcing cylindrical lens 240, the pulse signal within a short range, such as within the 0-4m range, can be enhanced to eliminate short-range blind spots.

[0078] Preferably, the signal emitting element 211 is located on the L-shaped bracket 212 of the laser emitting unit 210 and is distributed on two PCB boards on the bracket. Figure 6 The left and right directions of the L-shaped bracket 212 can be freely adjusted. For example, the L-shaped bracket 212 is placed on a guide rail, and the L-shaped bracket 212 can be driven by a micromotor to move along the guide rail, thereby adjusting the position of the signal emitting element 211. The signal emitting element 211 can optionally be an edge-emitting laser or a vertical cavity surface emitting laser (VCSEL).

[0079] As a preferred option, continue to refer to Figure 6 .like Figure 6 In the illustrated embodiment, the laser radar 200 further includes a photoelectric encoder 191. The photoelectric encoder 191 can be a transmissive photoelectric encoder or a reflective photoelectric encoder, which is fixedly connected to the housing of the laser radar 200 and cooperates with the code disk 190 of the rotating mirror unit 100 to provide relatively accurate angular information of the rotating mirror unit 100 through periodic changes in the transmissive / non-transmissive areas of the code channel area.

[0080] Figure 8 Shown Figure 4 The laser radar is shown in a cross-sectional view along the cutting plane OO. Figure 8As shown, the receiving unit 300 includes a receiving lens group 310, a second folding reflector 320, and a signal receiving board 330. The receiving lens group 310 is arranged downstream of the optical path of the rotating mirror unit 100, the second folding reflector 320 is arranged downstream of the receiving lens group 310, and the signal receiving board 330 is arranged downstream of the optical path of the second folding reflector 320. The signal receiving board 330 is provided with a signal receiving element (not shown in the figure), which can be an electronic device such as an APD (avalanche photodiode), a SPAD (Single Photon Avalanche Diode), or a SiPM (Silicon Photomultiplier). After being reflected by any reflective surface of the rotating mirror unit 100, the echo passes through the receiving lens group 310 and the second folding reflector 320 in sequence, and then enters the signal receiving board 330 and is received by the signal receiving element.

[0081] Preferably, the signal receiving board 330 is set to be position-adjustable for transceiver calibration, that is, the signal receiving board 330 can be adjusted along the optical axis so that its rear focal plane coincides with the signal receiving element.

[0082] Preferably, Figure 7 The structure of the emitting lens assembly according to one embodiment of the present invention is shown in FIG. As shown in the figure, the emitting lens assembly 230 includes a lens barrel 231 , a light blocking plate 232 , a spacer ring 233 and a pressure ring 234 .

[0083] The lens barrel 231 is provided with a lens or lens assembly. According to this embodiment, the edge of the lens barrel 231 has a partial trimming structure 235. The trimming structure 235 helps the emitted light beam emit more energy in a specific direction, thereby improving the laser radar's transmission efficiency at certain angles, especially when the emitted light beam is emitted at an angle close to 20°.

[0084] The light blocking plate 232 is usually made of a plastic sheet and is disposed in the lens barrel 231 to prevent stray light from entering the lens barrel 231. The spacer 233 and the pressure ring 234 fix the emitting lens group 230 in the lens barrel 231 and prevent interference and collision between them.

[0085] Figure 9 The structure of the receiving lens assembly according to one embodiment of the present invention is shown in FIG. As shown in the figure, the receiving lens assembly 310 includes a lens barrel 311, a light blocking plate 312, a spacer 313 and a pressure ring 314. The lens barrel 311 is provided with a lens.

[0086] Preferably, the edge of the lens barrel has a partial trimming structure 315. By adopting the trimming structure 315, the obstruction of the incident light beam is reduced, and the acceptance efficiency of the laser radar at some angles is improved.

[0087] The light blocking plate 312 is usually a thin sheet made of plastic or metal and is disposed in the lens barrel 311 to prevent stray light from entering the lens barrel 311. The spacer 313 and the pressure ring 314 fix the receiving lens group 310 in the lens barrel 231.

[0088] Those skilled in the art will understand that in order to improve the ranging capability, it is necessary to select a receiving lens with the largest possible aperture and a photosensitive element with a smaller photosensitive surface area, such as an APD.

[0089] Figure 10A FIG. 1 shows a schematic diagram of the relative position relationship between the transmitting lens group, the receiving lens group and the multi-faceted rotating mirror according to an embodiment of the present invention. Figure 10A As shown, the multi-faceted rotating mirror portion 110 of the rotating mirror unit 100 is a regular polygonal multi-faceted rotating mirror portion.

[0090] Preferably, the circumscribed circle radius of the regular polygon is R, and the aperture of the receiving lens 310 is the same as the circumscribed circle radius R. That is, the distance β2 between the optical axis of the receiving lens 310 and the rotation axis of the polygonal rotating mirror portion on a plane perpendicular to the optical axis is 0.5R.

[0091] According to a preferred solution, the aperture of the transmitting lens group 230 is smaller than the aperture of the receiving lens group 310 .

[0092] Preferably, the distance β1 between the optical axis of the emitting lens group 230 and the rotation axis of the multi-faceted rotating mirror portion on a plane perpendicular to the optical axis can be determined according to the aperture of the emitting lens group 230. More preferably, β1 is greater than β2.

[0093] For the output lens group, when it is located at a close distance from the multi-faceted rotating mirror, the ranging will be affected by the obstruction of the lens group itself; however, when it is at a longer distance, the vertical beam boundary will be affected by the height of the laser radar itself, which will affect its ranging.

[0094] That is, the smaller the lens group aperture, the closer it can be to the polygon mirror unit 110. Therefore, it is necessary to find a distance that is suitable for the current lens group aperture in the process of increasing the distance from the polygon mirror unit 110 to obtain the best ranging level.

[0095] According to another preferred embodiment, the distance α1 between the light-emitting surface of the emitting lens group 230 and the rotation axis of the multifaceted rotating mirror part 110 along the optical axis is 1.5R; and / or the distance α2 between the light-entering surface of the receiving lens group 310 and the rotation axis of the multifaceted rotating mirror part along the optical axis is 1.5R.

[0096] Those skilled in the art will appreciate that, when a suitable lens aperture is selected, an optimal ranging level can be achieved by using a distance of 1.5R.

[0097] Figure 10B The figure shows a schematic diagram of the vertical scale of the multi-faceted rotating mirror unit 110. The mirror surface height of the multi-faceted rotating mirror unit 110 is h2, the lower portion of the reflective surface of the multi-faceted rotating mirror unit 110 is h1, and the height of the light-shielding area between the upper and lower portions is h3. Preferably, the mirror surface height h2 can be related to the overall height of the device, the window height, and the position of the transceiver barrel.

[0098] According to a preferred embodiment of the present invention, the height h1 of the lower portion of the reflecting surface is 33.5 mm, the height of the upper portion of the reflecting surface is also 33.5 mm, the height h3 of the middle light-isolating area is 4 mm, and the height h2 of the entire mirror surface is 71 mm.

[0099] In summary, the present invention adopts a vehicle-mounted laser radar with a multi-faceted rotating mirror structure with a built-in motor, so that the motor is built into the rotating mirror frame of the multi-faceted rotating mirror part, thereby reducing the overall height and volume of the laser radar, and by setting corresponding angles between the multiple reflecting surfaces and the bottom surface of the multi-faceted rotating mirror part, the vertical scanning line density and scanning frame rate within the target ranging range are optimized while maintaining the horizontal angular resolution. At the same time, by adopting a partially cut-edge structure for the lens barrel of the transmitting lens group and / or the receiving lens group, the transmission and reception efficiency is improved, and the ranging capability of the laser radar within a large angle range is increased. The proposal of the present invention solves the problems of large size and low scanning accuracy of laser radar in the prior art.

[0100] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A laser radar, characterized in that: include: Rotating mirror unit, including: a multi-faceted rotating mirror portion, the multi-faceted rotating mirror portion having an even number of reflecting surfaces forming a polygon, for changing the angle of a light beam incident thereon, the multi-faceted rotating mirror portion of the rotating mirror unit rotating around its axis; a motor configured to drive the polygonal mirror portion to rotate around the axis; a light-isolating plate, the light-isolating plate being arranged in the light-isolating area; Each reflecting surface includes an upper portion and a lower portion separated by the light-isolating area, and the light-isolating plate rotates together with the multi-faceted rotating mirror portion to separate each reflecting surface into the upper portion and the lower portion; an emitting unit, the emitting unit being configured to emit a detection laser beam for detecting a target object, the detection laser beam being emitted after being reflected by an upper portion or a lower portion of one of the reflection surfaces of the rotating mirror unit; a receiving unit, the receiving unit being configured to receive an echo of the detection laser beam after being reflected on a target object and convert the echo into an electrical signal, the echo being received by the receiving unit after being reflected by a lower portion or an upper portion of one of the reflecting surfaces of the rotating mirror unit; The transmitting unit includes a transmitting lens group; the receiving unit includes a receiving lens group; the aperture of the transmitting lens group is smaller than the aperture of the receiving lens group; the distance between the optical axis of the transmitting lens group and the rotation axis of the multifaceted rotating mirror part on a plane perpendicular to the optical axis is greater than the distance between the optical axis of the receiving lens group and the rotation axis of the multifaceted rotating mirror part on a plane perpendicular to the optical axis.

2. The laser radar according to claim 1, characterized in that The emitting unit includes a laser emitting module and a first folding reflector; wherein, the laser emitting module is configured to emit laser light, and the laser light passes through the first folding reflector and the emitting lens group in sequence and then is emitted to the rotating mirror unit.

3. The laser radar according to claim 2, characterized in that The laser emitting module includes multiple laser emitters, wherein at least some of the laser emitters are arranged sequentially in the vertical direction, wherein the angle between the reflecting surface of the multi-faceted rotating mirror portion and the rotation axis can be determined according to the arrangement interval of the laser emitters in the vertical direction.

4. The laser radar according to claim 3, characterized in that The vertical arrangement interval of the laser emitters corresponds to a beam emission angle of 0.5°. The angle between two of the reflecting surfaces in the rotating mirror unit and the rotating axis is 0.09°, and the angle between the other two reflecting surfaces and the rotating axis is -0.09°, so as to achieve a resolution of up to 0.25° within a certain field of view.

5. The laser radar according to any one of claims 1 to 4, characterized in that: The emitting unit further includes a reinforcing cylindrical lens. After being emitted from the emitting lens group, the laser passes through the reinforcing cylindrical lens and is then emitted to the rotating mirror unit.

6. The laser radar according to any one of claims 1 to 4, characterized in that: The receiving unit includes a second folding reflector and a signal receiving board. After being reflected by the folding reflector unit, the echo passes through the receiving lens group and the second folding reflector in sequence, and then enters the signal receiving board.

7. The laser radar according to any one of claims 1 to 4, characterized in that: The transmitting lens group and / or the receiving lens group comprises a lens barrel and a lens arranged in the lens barrel, the edge of the lens barrel has a partial trimming structure, and a light blocking plate is arranged in the lens barrel.

8. The laser radar according to any one of claims 1 to 4, characterized in that: The multifaceted rotating mirror portion of the rotating mirror unit is a regular polygonal multifaceted rotating mirror portion, wherein the circumscribed circle radius of the regular polygon is R, the aperture of the receiving lens group is the same as the circumscribed circle radius, and the distance between the optical axis of the receiving lens group and the rotating axis of the multifaceted rotating mirror portion on a plane perpendicular to the optical axis is 0.5R.

9. The laser radar according to any one of claims 1 to 4, characterized in that: The receiving unit is located above the transmitting unit.

10. The laser radar according to any one of claims 1 to 4, characterized in that: The receiving unit is located below the transmitting unit.

11. A method for using a laser radar, characterized in that: The method of use uses the laser radar as described in any one of claims 1-10 for detection.

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