A prism and multi-line laser radar system

Abstract

The embodiment of the present invention discloses a prism and a multi-line laser radar system. The prism is used in the multi-line laser radar, and includes a top surface, a bottom surface, and at least three side surfaces between the top surface and the bottom surface, wherein at least two side surfaces include a transmitting area and a receiving area; the receiving area is located between the transmitting area and the top surface; along the direction from the top surface to the bottom surface, the transmitting area includes at least two reflecting surfaces arranged in sequence, and the angles between the at least two reflecting surfaces and the bottom surface are different. The prism provided by the embodiment of the present invention is used in the multi-line laser radar system, which can achieve the effect of reducing the production cost and difficulty of the multi-line laser radar system.

Description

Technical Field

[0001] The embodiments of the present invention relate to laser radar technology, and more particularly to a prism and multi-line laser radar system. Background Art

[0002] With the development of laser technology, laser scanning technology is increasingly widely used in measurement, transportation, driving assistance, mobile robots and other fields. LiDAR is a radar system that uses laser to detect the position, speed and other characteristic quantities of a target. Its working principle is to first emit a detection laser beam to the target, then compare the signal reflected from the target with the transmitted signal, and after appropriate processing, it can obtain information such as the distance, direction, height, speed, attitude, and even shape of the target.

[0003] At present, the most commonly used laser radars include single-line laser radar optical systems and multi-line laser radar optical systems. Among them, single-line laser radar uses a single beam to scan and has a small scanning area; multi-line laser radar scans the surrounding environment through motor rotation, and focuses the light returned from the irradiated object on the corresponding photoelectric sensor through a long-focus large target receiving optical system. It can emit and receive light beams of multiple arrays to scan a certain area of ​​the surrounding environment. Its disadvantage is that too many laser transmitters are required, and the receiver needs to have a larger photosensitive surface to receive the laser beam reflected by the target object. In addition, the processing circuit is relatively complex and the cost is relatively high. Summary of the invention

[0004] The embodiments of the present invention provide a prism and a multi-line laser radar system to reduce the manufacturing cost and difficulty of the multi-line laser radar system.

[0005] In a first aspect, an embodiment of the present invention provides a prism for use in a multi-line laser radar, comprising a top surface, a bottom surface, and at least three side surfaces located between the top surface and the bottom surface, wherein at least two of the side surfaces include a transmitting area and a receiving area; the receiving area is located between the transmitting area and the top surface;

[0006] Along the direction from the top surface to the bottom surface, the emitting area includes at least two reflecting surfaces arranged in sequence, and the angles between at least two of the reflecting surfaces and the bottom surface are different.

[0007] Optionally, along the direction from the top surface to the bottom surface, the angles between the reflecting surfaces located in the same emitting area and the bottom surface are in an arithmetic progression.

[0008] Optionally, each of the side surfaces includes at least four reflective surfaces;

[0009] In the same emitting area, the difference in angles between two adjacent reflecting surfaces close to the center of the emitting area and the bottom surface is the smallest.

[0010] Optionally, the angle between the side surface where the receiving area is located and the bottom surface is α1, and the angle between the reflecting surface of the emitting area and the bottom surface is α2, and α1=α2.

[0011] Optionally, the maximum value of the angle between the reflecting surface and the bottom surface is α3, the minimum value of the angle between the reflecting surface and the bottom surface is α4, and 0°<|α3-α4|<2°.

[0012] Optionally, on the same side surface, along the direction from the top surface to the bottom surface, the angle between the receiving area and the bottom surface and the angle between each of the reflecting surfaces of the emitting area and the bottom surface are in an arithmetic progression.

[0013] Optionally, the prism includes n pairs of oppositely disposed side surfaces, where n is a positive integer greater than or equal to 2;

[0014] Among the two opposite side surfaces, the angle between the reflective surface closest to the bottom surface and the bottom surface is greater than or smaller than the angle between the reflective surface closest to the bottom surface of at least one side surface between the two side surfaces and the bottom surface.

[0015] Optionally, among the two opposite side surfaces, the angles between the reflective surface closest to the bottom surface and the bottom surface are equal.

[0016] In a second aspect, an embodiment of the present invention further provides a multi-line laser radar system, comprising the prism described in any one of the first aspects above, and further comprising:

[0017] A rotating mechanism, the prism is located on the rotating mechanism, and the rotating mechanism drives the prism to rotate around the rotating axis of the rotating mechanism;

[0018] At least one group of transmitting and receiving components, the transmitting and receiving components include a transmitting unit and a receiving unit; the transmitting unit is located on one side of the prism and is used to transmit a laser beam, and the transmitting unit reflects the emitted laser beam through the transmitting area of ​​the prism and then irradiates the target object; the receiving unit and the transmitting unit in the same group of transmitting and receiving components are located on the same side of the prism, and the receiving unit is used to receive the laser beam reflected from the target object and then reflected through the receiving area of ​​the prism.

[0019] Optionally, also include:

[0020] An emitting mirror assembly, located between the emitting unit and the prism, for collimating the laser beam emitted by the emitting unit and irradiating it onto the emitting area of ​​the prism;

[0021] The receiving lens group is located between the receiving unit and the prism, and is used to focus the laser beam reflected by the receiving area of ​​the prism and irradiate it onto the receiving unit.

[0022] Optionally, the transmitting unit includes a laser light source, the receiving unit includes a photoelectric converter, and the number of the laser light sources is the same as the number of the photoelectric converters.

[0023] Optionally, a filter is also included, which is located between the receiving lens group and the receiving unit and is used to filter out ambient light.

[0024] Optionally, a 16-channel transimpedance amplifier is further included, which is electrically connected to the receiving unit and is used to amplify the photocurrent signal output by the receiving unit and convert it into a voltage signal.

[0025] The prism provided by the embodiment of the present invention includes a top surface, a bottom surface and at least three side surfaces between the top surface and the bottom surface, wherein at least two side surfaces include an emitting area and a receiving area; the receiving area is located between the emitting area and the top surface; along the direction from the top surface to the bottom surface, the emitting area includes at least two reflecting surfaces arranged in sequence, and the angles between the at least two reflecting surfaces and the bottom surface are different. By setting at least two side surfaces as reflecting surfaces with different inclination angles, the light beams irradiated on different reflecting surfaces when the prism rotates become multiple light beams, and by setting different changing trends of the inclination angles of the reflecting surfaces on the same side surface, the scanning resolution of the reflected light can be changed; when used for laser radar and rotating, multi-line scanning can be realized, thereby reducing the number of transmitters and receivers. By setting the emitting area and the receiving area, the emitting area can reflect the laser beam to the target object, and the receiving area can receive the laser beam reflected by the target object and reflect it to the receiver. Since the same side includes both a transmitting area and a receiving area, the laser beam reflected from the transmitting area of ​​the side to the target object can be received by the receiving area of ​​the side after being reflected by the target object, and then reflected to the receiver. Therefore, there is no need to specially set up a receiver with a large photosensitive surface to receive the laser beam reflected back from the target object, thereby reducing the production cost and difficulty of the multi-line laser radar system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic diagram of a three-dimensional structure of a prism provided by an embodiment of the present invention;

[0027] Figure 2 yes Figure 1 A schematic front view of the prism shown;

[0028] Figure 3 A schematic diagram of a side reflection light path of a prism is provided;

[0029] Figure 4 yes Figure 1 Another schematic front view of the prism shown;

[0030] Figure 5 yes Figure 1 Another schematic front view of the prism shown;

[0031] Figure 6 yes Figure 1 Another schematic front view of the prism shown;

[0032] Figure 7 is a schematic structural diagram of a multi-line laser radar system provided by an embodiment of the present invention;

[0033] Figure 8 It is a schematic diagram of the structure of another laser radar system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0035] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. It should be noted that the directional words such as "upper", "lower", "left", "right" and the like described in the embodiments of the present invention are described at the angles shown in the accompanying drawings and should not be understood as limitations on the embodiments of the present invention. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is formed "on" or "under" another element, it can not only be directly formed "on" or "under" another element, but also indirectly formed "on" or "under" another element through an intermediate element. The terms "first", "second", etc. are only used for descriptive purposes and do not represent any order, quantity or importance, but are only used to distinguish different components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific circumstances.

[0036] Figure 1 FIG. 1 is a schematic diagram of a three-dimensional structure of a prism provided by an embodiment of the present invention. Figure 2 for Figure 1 The prism provided in the embodiment of the present invention can be applied to a multi-line laser radar, as shown in FIG. Figure 1The prism includes a top surface 10, a bottom surface 20 and at least three side surfaces 30 located between the top surface 10 and the bottom surface 20, wherein at least two side surfaces 30 include an emitting area 301 and a receiving area 302; the receiving area 302 is located between the emitting area 301 and the top surface 10; along the direction from the top surface 10 to the bottom surface 20, the emitting area 301 includes at least two reflecting surfaces arranged in sequence, and the angles between the at least two reflecting surfaces and the bottom surface 20 are different.

[0037] It should be noted that Figure 1 The shape of the prism shown as a quadrangular prism is only for illustration and is not intended to limit the present invention. In a specific implementation, the number of the side surfaces 30 can be set according to actual needs. At least two side surfaces 30 between the top surface 10 and the bottom surface 20 are set as reflective surfaces, for example, Figure 1 The reflective surface can be formed by coating the side surface with a reflective film. Figure 2 for Figure 1 A front view schematic diagram showing the shape of the right side surface. Figure 2 The right side surface shown includes a receiving area 302 located at the top and a transmitting area 301 located at the bottom, and the transmitting area 301 includes at least two reflecting surfaces ( Figure 2 3 reflecting surfaces 301a, 301b and 301c are shown as examples, and the angles between at least two reflecting surfaces and the bottom surface 20 are different, for example Figure 2 The angles between the middle reflective surface 301a and the reflective surface 301c and the bottom surface are the same, while the angles between the reflective surface 301a and the reflective surface 301b and the bottom surface are different. It can be understood that when the side surfaces are regarded as a whole, at least two side surfaces have different angles with the bottom surface. It should be noted that Figure 2 The short dashed line on the right side of the middle is for schematically showing the angles between each reflecting surface and the bottom surface, and is not the actual outline of the prism.

[0038] It is understandable that when the laser beam emitted by the laser is emitted to the emission area of ​​the prism, due to the different angles between different reflection surfaces and the bottom surface, different reflected beams will be formed in the vertical direction of the space (perpendicular to the top surface and the bottom surface). When the prism rotates, the beam can scan the target object, for example, Figure 1 For the prism with four sides shown, if all four sides are set as reflecting surfaces, the emitting area of ​​each side includes three reflecting surfaces, and the distance of the reflected light in the vertical direction can be adjusted by adjusting the inclination angles of the three reflecting surfaces (for example, dense in the middle and sparse on both sides). When the prism rotates one circle, the laser beam emitted by a column of lasers can form four scanning beams with different resolutions. When used in a laser radar, four-line multi-resolution scanning can be achieved by a column of lasers, which greatly reduces the complexity and cost of multi-line laser radar.

[0039] Figure 3FIG. 1 is a schematic diagram of a side reflection light path of a prism provided by an embodiment of the present invention. Figure 3 , Figure 3 The upper middle portion is the receiving area 302, and the lower portion is the transmitting area 301. For ease of description, Figure 3 Only the receiving area 302 and the transmitting area 301 are shown in the figure. The transmitting area 301 reflects the laser beam incident from the right (emitted by the light source) to the left, and the propagation direction of the laser beam reflected from the transmitting area 301 is from right to left; the receiving area 302 reflects the laser beam incident from the right (reflected by the target object) to the right, and the propagation direction of the laser beam reflected from the receiving area 302 is from left to right. By setting the receiving area on the side of the prism, the beam reflected by the target object can be reflected and converged to the receiver, effectively reducing the requirements for the field of view of the receiving lens, reducing the area of ​​the photosensitive surface of the receiver, and reducing the cost of the multi-line laser radar system.

[0040] The technical solution of this embodiment is to set at least two side surfaces as reflective surfaces with different inclination angles so that the light beams irradiated on different reflective surfaces become multiple light beams when the prism rotates. By setting different changing trends of the inclination angles of the reflective surfaces on the same side, the scanning resolution of the reflected light can be changed; when used for laser radar and rotated, multi-line scanning can be achieved, thereby reducing the number of transmitters and receivers. By setting the emission area and the receiving area, the emission area can reflect the laser beam to the target object, and the receiving area can receive the laser beam reflected by the target object and reflect it to the receiver. Since the same side includes both the emission area and the receiving area, the laser beam reflected from the emission area of ​​the side to the target object can be received by the receiving area of ​​the side after being reflected by the target object, and then reflected to the receiver, so there is no need to specially set up a large photosensitive surface receiver to receive the laser beam reflected back from the target object, so as to achieve the effect of reducing the production cost and difficulty of the multi-line laser radar system.

[0041] On the basis of the above technical solution, optionally, along the direction from the top surface to the bottom surface, the angles between the reflecting surfaces and the bottom surface located in the same emitting area are in an arithmetic progression.

[0042] For example, Figure 4 Shown Figure 1 Another schematic diagram of the prism shown in the figure. Figure 4 , along the direction from top to bottom, the angles between each reflecting surface of the emitting area 301 and the bottom surface are distributed in an equidistant manner, that is, the angles between each reflecting surface and the bottom surface are distributed in a gradient manner. For example, from top to bottom, the angles between each reflecting surface 301a, 301b and 301c and the bottom surface are 88°, 88.5°, 89°, or 89°, 88.5°, 88°, respectively. Figure 4This arrangement can make the reflected light from each reflecting surface evenly spaced in the vertical direction, thus achieving equal-resolution scanning in space.

[0043] Optionally, each side surface includes at least four reflecting surfaces; in the same emitting area, the difference in angle between two adjacent reflecting surfaces close to the center of the emitting area and the bottom surface is the smallest.

[0044] For example, Figure 5 Shown Figure 1 Another schematic front view of the prism shown. Figure 5 , along the direction from top to bottom, the difference in angle between each reflecting surface of the emitting area 301 and the bottom surface shows a trend of increasing from the middle to both sides, for example, from top to bottom, the angles between each reflecting surface 301a, 301b, 301c and 301d and the bottom surface are 88°, 88.4°, 88.6°, 89°, or 89°, 88.6°, 88.4°, 88°, respectively. This arrangement can make the reflected light of each reflecting surface closer in the middle area in the vertical direction (high resolution), and the detection distance farther, and farther in the two side areas (low resolution), and the detection distance closer. It can be understood that when the number of reflecting surfaces is an odd number, the difference in angle between the middle reflecting surface and the two adjacent reflecting surfaces and the bottom surface can be set to be the same, and both are minimum values.

[0045] It should be noted that the above examples of setting the number of reflecting surfaces and the size of the angle in the emitting area are only schematic. The angles between each reflecting surface and the bottom surface of the same reflecting area can be set according to actual needs. The angles between each reflecting surface and the bottom surface at corresponding positions of the reflecting areas on different sides can be the same or different, and the embodiments of the present invention are not limited to this.

[0046] Optionally, the angle between the side where the receiving area is located and the bottom surface is α1, and the angle between a reflecting surface of the emitting area and the bottom surface is α2, α1 = α2. Optionally, on the same side, along the direction from the top surface to the bottom surface, the angle between the receiving area and the bottom surface and the angles between each reflecting surface of the emitting area and the bottom surface are in an arithmetic progression.

[0047] For example, continue to refer to Figure 4 The angle between the receiving area 302 and the bottom surface can be gradiently distributed with the angles between the reflecting surfaces of the emitting area and the bottom surface, for example, it can be 87.5°, or the same as the angle between any one of the reflecting surfaces and the bottom surface (for example, 88°, 88.5°, or 89°), or none of them are the same. In other embodiments, the angle between the receiving area and the bottom surface can also be designed according to the angle of the light to be reflected.

[0048] Optionally, the maximum value of the angle between the reflecting surface and the bottom surface is α3, the minimum value of the angle between the reflecting surface and the bottom surface is α4, and 0°<|α3-α4|<2°.

[0049] It is understandable that the advantage of such a setting is that it ensures that all the reflecting surfaces are not tilted too much, and ensures that the multi-line radar system has good resolution. It should be noted that in other embodiments, the difference between α3 and α4 can also be greater than or equal to 2°.

[0050] Optionally, the prism includes n pairs of oppositely arranged side surfaces, where n is a positive integer greater than or equal to 2; among two opposite side surfaces, the angle between the reflecting surface closest to the bottom surface and the bottom surface is greater than or less than the angle between the reflecting surface closest to the bottom surface and the bottom surface of at least one side surface between the two side surfaces.

[0051] For example, Figure 6 Shown Figure 1 Another schematic front view of the prism shown. Figure 6 , taking n=2 as an example, the angles between the lowest reflection surface 301c′ on the left side and the lowest reflection surface 301c on the right side and the bottom surface are both greater than or less than the angle between the bottom surface of at least one of the front side and the rear side, for example, the angle between the reflection surface 301c′ and the bottom surface is 89°, the angle between the reflection surface 301c and the bottom surface is 88°, and the angle between the lowest reflection surface on the front side and the bottom surface is 87°. This arrangement prevents the angle between the reflection surface and the bottom surface from gradually increasing or decreasing in a direction around the prism, thereby avoiding the occurrence of serious uneven moments of multiple reflection surfaces of the prism, and helping to achieve moment balance of multiple reflection surfaces when the prism rotates.

[0052] Optionally, among the two opposite side surfaces, the angles between the reflective surface closest to the bottom surface and the bottom surface are equal.

[0053] It can be understood that by setting the angle between the lowest reflecting surface and the bottom surface of the two opposite side surfaces to be equal, the two opposite reflecting surfaces have the same inclination degree. When the prism rotates, the two opposite reflecting surfaces will not produce uneven torque, thereby further achieving torque balance of the multiple reflecting surfaces of the prism.

[0054] Figure 7A structural schematic diagram of a multi-line laser radar system provided in an embodiment of the present invention, the laser radar system provided in this embodiment includes any one of the prisms 100 provided in the above embodiments, and also includes a rotating mechanism 200, the prism 100 is located on the rotating mechanism 200, and the rotating mechanism 200 drives the prism 100 to rotate around the rotation axis of the rotating mechanism 200; at least one group of transmitting and receiving components 310, the transmitting and receiving components 310 include a transmitting unit 300 and a receiving unit 400; the transmitting unit 300 is located on one side of the prism 100, and is used to transmit a laser beam, and the transmitting unit 300 reflects the emitted laser beam through the transmitting area of ​​the prism 100 and irradiates the target object; the receiving unit 400 and the transmitting unit 300 in the same group of the transmitting and receiving components 310 are located on the same side of the prism 100, and the receiving unit 400 is used to receive the laser beam reflected from the target object through the receiving area of ​​the prism 100.

[0055] It is understood that the rotating mechanism 200 may include a stepping motor, and the rotation axis of the rotating mechanism 200 coincides with the rotation axis of the prism 100; Figure 7 Taking a group of transmitting and receiving components 310 as an example, when there are multiple groups of transmitting and receiving components 310, they can respectively correspond to one side of the prism 100. The transmitting unit 300 can include a pulse laser for emitting a pulse light beam; the receiving unit 400 can include a photoelectric converter for converting an optical signal into an electrical signal, and by processing the electrical signal, information such as the distance and shape of the target object can be obtained.

[0056] The technical solution of this embodiment is to set at least two side surfaces as reflection surfaces with different inclination angles, so that when the prism rotates, the light beams irradiated on different reflection surfaces become multiple light beams. By setting different changing trends of the inclination angles of the reflection surfaces on the same side surface, the scanning resolution of the reflected light can be changed; when the rotating mechanism drives the prism to rotate, multi-line scanning can be achieved, thereby reducing the number of transmitting units and receiving units. By setting the transmitting area and the receiving area on the side surface of the prism, the transmitting area can reflect the laser beam to the target object, and the receiving area can receive the laser beam reflected by the target object and reflect it to the receiver. Since the same side surface includes both the transmitting area and the receiving area, the laser beam reflected by the transmitting area of ​​the side surface to the target object can be received by the receiving area of ​​the side surface after being reflected by the target object, and then reflected to the receiver, so that there is no need to specially set up a large photosensitive surface receiver to receive the laser beam reflected back by the target object, so as to achieve the effect of reducing the production cost and difficulty of the multi-line laser radar system. In addition, a rotating mechanism is used to drive the prism to rotate instead of rotating the entire machine to achieve horizontal scanning, which improves the mechanical properties of the product (vibration resistance, impact resistance, and heat dissipation, etc.). At the same time, the entire radar does not require wireless power transmission and wireless transmission of large data, which simplifies the system structure.

[0057] Based on the above embodiment, optionally, Figure 8 FIG. 2 is a schematic diagram of the structure of another laser radar system provided by an embodiment of the present invention. Figure 8 The laser radar system provided in this embodiment also includes: a transmitting mirror group 500, located between the transmitting unit 300 and the prism 100, for collimating the laser beam emitted by the transmitting unit 300 and irradiating it onto the emitting area of ​​the prism 100; a receiving mirror group 600, located between the receiving unit 400 and the prism 100, for focusing the laser beam reflected by the receiving area of ​​the prism 100 and irradiating it onto the receiving unit 400.

[0058] It is understandable that the transmitting lens group 500 and the receiving lens group 600 can use the same lens group, and the specific implementation can be based on the actual optical path design, which is not limited in the embodiment of the present invention.

[0059] Optionally, the transmitting unit includes a laser light source, the receiving unit includes a photoelectric converter, and the number of the laser light sources is the same as the number of the photoelectric converters.

[0060] It can be understood that in a specific implementation, the transmitting unit can use a semiconductor laser to emit laser pulses, and the receiving unit can use a photoelectric converter formed by an avalanche diode (APD). In order to further improve the accuracy of the lidar, multiple lasers and photoelectric converters can be set. The multiple lasers and photoelectric converters can be arranged in one column or in multiple columns, and the number and arrangement of the lasers and photoelectric converters are the same.

[0061] Optional, continue to refer to Figure 8 The laser radar system also includes a filter 700, which is located between the receiving lens group 600 and the receiving unit 400 and is used to filter out ambient light.

[0062] It is understandable that since there may be ambient light such as sunlight and various lights in the environment that interfere with the signal received by the receiving unit 400, by setting the filter 700, the ambient light can be filtered out to improve the measurement accuracy of the multi-line laser radar system.

[0063] Optionally, the multi-line laser radar system provided in the embodiment of the present invention further includes a 16-channel transimpedance amplifier ( Figure 8 The receiving unit is electrically connected to the receiving unit and is used to amplify the photocurrent signal output by the receiving unit and convert it into a voltage signal, thereby improving the measurement accuracy.

[0064] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A prism, characterized in that: Used in a multi-line laser radar, comprising a top surface, a bottom surface, and at least three side surfaces located between the top surface and the bottom surface, wherein at least two of the side surfaces include a transmitting area and a receiving area; the receiving area is located between the transmitting area and the top surface; Along the direction from the top surface to the bottom surface, the emitting area includes at least two reflecting surfaces arranged in sequence, and the angles between at least two of the reflecting surfaces and the bottom surface are different; Along the direction from the top surface to the bottom surface, the included angles between the reflecting surfaces located in the same emitting area and the bottom surface are in an arithmetic progression; Or each of the side surfaces includes at least four reflective surfaces; In the same emission area, the difference in angles between two adjacent reflection surfaces close to the center of the emission area and the bottom surface is the smallest; The maximum value of the angle between the reflecting surface and the bottom surface is α3, the minimum value of the angle between the reflecting surface and the bottom surface is α4, and 0°<|α3-α4|<2°.

2. The prism according to claim 1, characterized in that The included angle between the side surface where the receiving area is located and the bottom surface is α1, and the included angle between the reflecting surface of the emitting area and the bottom surface is α2, and α1=α2.

3. The prism according to claim 1, characterized in that On the same side surface, along the direction from the top surface to the bottom surface, the angle between the receiving area and the bottom surface and the angle between each of the reflecting surfaces of the emitting area and the bottom surface are in an arithmetic progression.

4. The prism according to claim 1, characterized in that The prism includes n pairs of oppositely disposed side surfaces, where n is a positive integer greater than or equal to 2; Among the two opposite side surfaces, the angle between the reflective surface closest to the bottom surface and the bottom surface is greater than or smaller than the angle between the reflective surface closest to the bottom surface of at least one side surface between the two side surfaces and the bottom surface.

5. The prism according to claim 4, characterized in that Of the two opposite side surfaces, the reflection surface closest to the bottom surface has the same included angle with the bottom surface.

6. A multi-line laser radar system, characterized in that: The prism according to any one of claims 1 to 5 further comprises: A rotating mechanism, the prism is located on the rotating mechanism, and the rotating mechanism drives the prism to rotate around the rotating axis of the rotating mechanism; At least one group of transmitting and receiving components, the transmitting and receiving components include a transmitting unit and a receiving unit; the transmitting unit is located on one side of the prism and is used to transmit a laser beam, and the transmitting unit reflects the emitted laser beam through the transmitting area of ​​the prism and then irradiates the target object; the receiving unit and the transmitting unit in the same group of transmitting and receiving components are located on the same side of the prism, and the receiving unit is used to receive the laser beam reflected from the target object and then reflected through the receiving area of ​​the prism.

7. The multi-line laser radar system according to claim 6, characterized in that: Also includes: An emitting mirror assembly, located between the emitting unit and the prism, for collimating the laser beam emitted by the emitting unit and irradiating it onto the emitting area of ​​the prism; The receiving lens group is located between the receiving unit and the prism, and is used to focus the laser beam reflected by the receiving area of ​​the prism and irradiate it onto the receiving unit.

8. The multi-line laser radar system according to claim 6, characterized in that: The transmitting unit includes a laser light source, the receiving unit includes a photoelectric converter, and the number of the laser light sources is the same as the number of the photoelectric converters.

9. The multi-line laser radar system according to claim 7, characterized in that: It also includes a filter, which is located between the receiving lens group and the receiving unit and is used to filter out ambient light.

10. The multi-line laser radar system according to claim 6, characterized in that: It also includes a 16-channel transimpedance amplifier, which is electrically connected to the receiving unit and is used to amplify the photocurrent signal output by the receiving unit and convert it into a voltage signal.

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