CN219456484U

CN219456484U - Laser radar

Info

Publication number: CN219456484U
Application number: CN202223362972.4U
Authority: CN
Inventors: 张明伟; 杨昆
Original assignee: Wuhan Wanji Photoelectric Technology Co Ltd
Current assignee: Wuhan Wanji Photoelectric Technology Co Ltd
Priority date: 2022-12-08
Filing date: 2022-12-08
Publication date: 2023-08-01
Anticipated expiration: 2032-12-08

Abstract

The utility model belongs to the field of laser detection, and particularly relates to a laser radar which comprises a laser emitting device, a laser receiving device and a beam splitting device. The spectroscopic device includes a first region, a second region surrounding the first region, and a third region surrounding the second region. When the second area reflects the emitted light to the target object, the first area and the third area transmit the back wave light, and angle selective transmission films are arranged on the first area and the third area; or when the second area transmits the emitted light to the target object, the first area and the third area reflect the back wave light, and the first area and the third area are provided with angle selective reflection films. The shielding of the light splitting device to echo light during short-range detection of the coaxial light path laser radar is reduced by utilizing the first area, and the short-range blind area of the laser radar is reduced. The angle selective transmission film or the angle selective reflection film is arranged on the beam splitting device, which is beneficial to miniaturization and assembly of the laser radar.

Description

Laser radar

Technical Field

The utility model relates to the technical field of laser detection, in particular to a laser radar.

Background

Today, lidars, particularly vehicle mounted lidars, are demanding in terms of volume size, and conventional parallel axis schemes are large in size and complex to assemble. The laser radar adopting the coaxial light path can greatly reduce the radar size, but in the laser radar adopting the existing coaxial light path, a light splitting device is generally used for turning a transmitting light path and a receiving light path to the same optical axis, and as the light splitting device is positioned on the optical axis, an echo light signal fed back by a short-distance target object can be blocked by the light splitting device, so that the near-field detection capability of the laser radar is weaker.

Meanwhile, after the laser radar of the coaxial light path emits emitted light, the laser radar often receives a filter cover or stray light reflected by a structural member, and the close-range signal amplitude is severely interfered due to the fact that the distance from a receiving system is relatively close, so that the signal quality of the laser radar is seriously affected. At present, stray light is eliminated mainly through structural member surface treatment, or light is prevented from striking a reflecting surface, so that the structural design requirement is high, and miniaturization and assembly of the laser radar are seriously hindered.

Disclosure of Invention

The embodiment of the utility model provides a laser radar, which is used for solving the technical problems that an echo light signal fed back by a close-range target object in the laser radar of the existing coaxial light path is blocked by a light splitting device, so that the near-field detection capability of the laser radar is weaker, and the structural design requirement is higher in the existing stray light eliminating mode.

To achieve the above object, the present utility model provides a lidar comprising:

the laser emission device is used for generating emission light, and the emission light is reflected by the target object to form echo light;

the laser receiving device is used for receiving the echo light;

the beam splitting device is coaxial with the echo light and comprises a first area, a second area surrounding the first area and a third area surrounding the second area;

when the second area reflects the emitted light to the target object, the first area and the third area transmit the echo light, and angle selective transmission films are arranged on the first area and the third area and used for transmitting light rays with incidence angles within the divergence angle range of the echo light and blocking light rays with incidence angles outside the divergence angle range of the echo light; or (b)

When the second region transmits the emitted light to the target object, the first region and the third region reflect the echo light, and angle selective reflection films are arranged on the first region and the third region and used for reflecting light rays with incidence angles within the divergence angle range of the echo light and transmitting or absorbing light rays with incidence angles outside the divergence angle range of the echo light.

Optionally, when the first region and the third region transmit the echo light, the first region is a light hole; or (b)

The first region is a light-transmitting body.

Optionally, when the second area reflects the emitted light to the target object, the second area is a high-reflection mirror; or (b)

The second region is a transflector having a reflectance greater than a transmittance.

Optionally, when the first region and the third region reflect the echo light, the first region and the third region are high-reflection mirrors; or (b)

The first region and the third region are transflectors having a reflectivity greater than a transmissivity.

Optionally, the second region is elliptical.

Optionally, the angle selective transmission film and the angle selective reflection film each comprise a plurality of dielectric films, and at least two of the dielectric films have different light refractive indexes.

Optionally, the laser receiving device includes:

a receiving lens group including a plurality of lenses arranged in order from an object side to an image side;

the detector is arranged at the image side of the receiving lens group and is used for receiving the echo light; and

the angle selective transmission film is arranged on the lens positioned on the object side and/or the lens positioned on the image side of the receiving lens group, and is used for transmitting light rays with incidence angles within the range of the divergence angle of the echo light and blocking light rays with incidence angles outside the range of the divergence angle of the echo light.

Optionally, the laser radar further includes a turning mirror, the emitted light with the spectroscope effect is reflected by the turning mirror and then exits to the three-dimensional space, and the echo light is received by the laser receiving device after being reflected by the turning mirror.

Optionally, the surface of the turning mirror is provided with an angle selective reflection film for reflecting light rays having an incident angle within the range of the divergence angle of the echo light and for transmitting or absorbing light rays having an incident angle outside the range of the divergence angle of the echo light.

Optionally, the laser radar further includes a filter cover, the filter cover is arranged on the laser emitting device and the laser receiving device, an angle selective transmission film is arranged on the surface of the filter cover, and the angle selective transmission film is used for transmitting light rays with incidence angles within the divergence angle range of the echo light and is used for blocking light rays with incidence angles outside the divergence angle range of the echo light.

The laser radar provided by the utility model has the beneficial effects that: compared with the prior art, in the laser radar, the beam splitting device is arranged in a partitioning mode and controls the angle coating transmittance of the corresponding area, the shielding of the beam splitting device on echo light during close range detection of the coaxial light path laser radar is reduced by utilizing the first area, the close range blind area of the laser radar is reduced, and the close range detection capability of the laser radar is improved. Meanwhile, when the first area and the third area transmit the echo light, the transmission film is selected to transmit the light rays with the incident angle within the range of the divergence angle of the echo light through the angle, and the light rays with the incident angle outside the range of the divergence angle of the echo light are blocked; or when the first area and the third area reflect the echo light, the angle selective reflection film reflects the light rays with the incident angles within the range of the divergence angle of the echo light and is used for transmitting or absorbing the light rays with the incident angles outside the range of the divergence angle of the echo light, so that stray light entering the detector can be effectively reduced. The angle selective transmission film or the angle selective reflection film is arranged on the light splitting device, so that the miniaturization and the assembly of the laser radar are facilitated.

Drawings

In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Wherein:

FIG. 1 is a schematic view showing an internal structure of a lidar according to an embodiment of the present utility model;

FIG. 2 is a schematic view of an optical path structure of a laser radar according to an embodiment of the present utility model;

FIG. 3 is a schematic view of a beam splitting device in the laser radar shown in FIG. 2;

FIG. 4 is a schematic cross-sectional view of a beam splitting device and an angle selective transmission film in the lidar shown in FIG. 2;

FIG. 5 is a schematic view showing an optical path structure of another lidar according to an embodiment of the present utility model;

FIG. 6 is a schematic view of a beam splitting device in the laser radar shown in FIG. 5;

FIG. 7 is a schematic cross-sectional view of a spectroscopic assembly and an angle selective reflective film in the lidar shown in FIG. 5;

fig. 8 is a schematic structural view of a laser receiving device in a laser radar according to an embodiment of the present utility model;

FIG. 9 is a schematic view showing an optical path structure of another lidar according to an embodiment of the present utility model;

FIG. 10 is a schematic view showing the optical path structure of still another lidar according to an embodiment of the present utility model;

fig. 11 is a schematic view of the divergence angle (shown as α in the figure) of the echo light on the spectroscopic device.

Description of main reference numerals:

10. a target;

100. a laser emitting device;

200. a laser receiving device; 210. receiving a lens group; 220. a detector; 230. an angularly selective permeable membrane;

300. a spectroscopic device; 301. a first region; 302. a second region; 303. a third region; 310. a substrate; 320. an annular high-reflection film; 330. a circular high-reflection film; 340. an annular high-reflection film;

400. an angle selection transmissive film;

500. an angle selective reflection film;

600. a turning mirror;

700. an angle selective reflective film;

800. a filter cover;

900. the angle is selected to penetrate the membrane.

Detailed Description

In order that the utility model may be readily understood, a more complete description of the utility model will be rendered by reference to the appended drawings. Preferred embodiments of the present utility model are shown in the drawings. This utility model may, however, be embodied in many other different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are merely for convenience in describing and simplifying the description based on the orientation or positional relationship shown in the drawings, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be construed as limiting the utility model.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present utility model, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs. The terminology used herein in the description of the utility model is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

As described in the background art, the echo light signal fed back by the near-distance target object in the laser radar of the existing coaxial light path is blocked by the light splitting device, so that the near-field detection capability of the laser radar is weaker, and meanwhile, the current stray light eliminating mode has higher requirements on structural design, so that miniaturization and assembly of the laser radar are seriously hindered.

In order to solve the above-described problems, an embodiment of the present utility model provides a laser radar including a laser emitting apparatus 100, a laser receiving apparatus 200, and a spectroscopic apparatus 300, as shown in fig. 1 to 7. The laser emitting device 100 is configured to generate emitted light, and the emitted light is reflected by the target object 10 to form a return wave. The laser light receiving device 200 is used for receiving the reflected wave light. The emitted light acting through the spectroscopic device 300 is coaxial with the echo light, and the spectroscopic device 300 includes a first region 301, a second region 302 surrounding the first region 301, and a third region 303 surrounding the second region 302.

When the second area 302 reflects the emitted light to the target object 10, the first area 301 and the third area 303 transmit the echo light, and the first area 301 and the third area 303 are provided with an angle selective transmission film 400, and the angle selective transmission film 400 is used for transmitting the light with the incident angle within the divergence angle range of the echo light and is used for blocking the light with the incident angle outside the divergence angle range of the echo light; or (b)

When the second region 302 transmits the emitted light to the target object 10, the first region 301 and the third region 303 reflect the echo light, and the first region 301 and the third region 303 are provided with an angle selective reflection film 500, the angle selective reflection film 500 is used for reflecting light rays having an incident angle within the range of the divergence angle of the echo light, and is used for transmitting or absorbing light rays having an incident angle outside the range of the divergence angle of the echo light.

As shown in fig. 10 and 11, in fig. 10, external ambient light passes through the filter cover 800 and then enters the laser receiving device 200 through the beam splitting device 300, and stray light is generated as shown by a dotted line in the figure. Stray light is typically incident on the spectroscopic device 300 at an angle of incidence (shown at a in fig. 11) different from that of the return light (shown as a solid line in the figure).

In the embodiment of the utility model, the first area 301 is utilized to reduce the shielding of the coaxial light path laser radar on the return light during the short-distance detection by the light splitting device 300, reduce the short-distance blind area of the laser radar and improve the short-distance detection capability of the laser radar by arranging the light splitting device 300 in a partitioned manner and controlling the angle coating transmittance of the corresponding area. Meanwhile, when the first region 301 and the third region 303 transmit the echo light, the transmission film 400 transmits the light having the incident angle within the range of the divergence angle of the echo light through the angle selection, and blocks the light having the incident angle outside the range of the divergence angle of the echo light; or, when the first region 301 and the third region 303 reflect the echo light, the angle selective reflection film 500 reflects the light having the incident angle within the divergence angle range of the echo light, and is used to transmit or absorb the light having the incident angle outside the divergence angle range of the echo light, so that the stray light entering the detector 220 can be effectively reduced. Since the angle selective transmission film 400 or the angle selective reflection film 500 is provided on the spectroscopic apparatus 300, miniaturization and assembly of the laser radar are facilitated.

It can be appreciated that, when the second region 302 reflects the emitted light to the target object 10 and the first region 301 and the third region 303 transmit the back-wave light, the beam splitting device 300 is suitable for use in the center-reflection type coaxial receiving-transmitting lidar, as shown in fig. 2; when the second region 302 transmits the emitted light to the target 10 and the first region 301 and the third region 303 reflect the return light, the beam splitting device 300 is suitable for use in a center-transmission type coaxial transmitting-receiving lidar, as shown in fig. 5.

In this embodiment, the angle selective transmission film 400 or the angle selective reflection film 500 is directly coated on the spectroscopic apparatus 300 through a coating process. Of course, in other embodiments, the angle selective transmission film 400 or the angle selective reflection film 500 may be manufactured first, and then the angle selective transmission film 400 or the angle selective reflection film 500 may be adhered to the spectroscopic apparatus 300.

In one embodiment, as shown in fig. 2-3, when the first region 301 and the third region 303 transmit the back wave light, the first region 301 is a light hole; alternatively, the first region 301 is a light-transmitting body.

The first area 301 for transmitting light is formed in a hole digging mode, so that the first area 301 has full light transmitting capacity, the strength of the acquired echo signals is improved, and the close range detection capacity of the laser radar is further improved. The first area 301 is formed by adopting the light-transmitting body, so that one punching process is reduced compared with the first area 301 formed by adopting a punching mode, and the processing and the manufacturing are convenient.

In particular, the light transmissive body may be a high lens or the light transmissive body may be a transflector having a transmittance greater than a reflectance.

When the light-transmitting body adopts a high lens, transmission of the echo light is facilitated, and the intensity of the acquired echo signal is improved. Preferably, the transmittance of the high lens is greater than 99.5%. Specifically, the light splitting device 300 may be formed by plating an annular high-reflection film on one surface of a rectangular optical glass, where the annular high-reflection film and an annular portion of the optical glass corresponding to the high-reflection film together form a second area 302 of the light splitting device 300, for reflecting the emitted light to the target object 10; the portion of the optical glass corresponding to the inner region of the annular high-reflection film forms the first region 301; the portion of the optical glass corresponding to the outer region of the annular highly reflective film forms the third region 303 described above.

When the transparent body adopts the transmission reflector with the transmittance larger than the reflectance, the transparent body can realize the transmission of the back wave light, and can also play a role in reflecting the emitted light to the target object 10 to a certain extent, thereby improving the intensity of the emitted signal. Specifically, the transflector may be formed by plating a reflective transmissive film on the optical glass of the above-described spectroscopic apparatus 300 in a region other than the annular highly reflective film.

In one specific embodiment, as shown in fig. 2-3, the second region 302 is a high-reflectivity mirror when the second region 302 reflects the emitted light to the target 10; alternatively, the second region 302 is a transflector having a reflectance greater than a transmittance.

When the second region 302 employs a high reflection mirror, reflection of the emitted light is facilitated and the emitted signal intensity is improved. Preferably, the reflectivity of the high reflectivity mirror is greater than 99.5%.

Specifically, as shown in fig. 4, the light splitting device 300 may be formed by plating an annular high-reflection film 320 on one surface of a substrate 310 (which may be made of optical glass or transparent plastic, etc.), where the annular high-reflection film 320 and an annular portion corresponding to the high-reflection film on the transparent carrier together form a second area 302 of the light splitting device 300, and are used for reflecting the emitted light to the target 10.

When the second area 302 adopts a transmissive mirror with a reflectivity greater than the transmittance (specifically, the transmissive mirror may be made by replacing the annular high-reflection film 320 in the spectroscopic device 300 with a reflective transmissive film), the second area 302 can not only reflect the emitted light, but also play a role in transmitting the echo light to a certain extent, and improve the echo signal strength.

In one embodiment, as shown in fig. 5-6, when the first region 301 and the third region 303 reflect the return light, the first region 301 and the third region 303 are highly reflective mirrors; alternatively, the first region 301 and the third region 303 are transmissive mirrors having a reflectance greater than a transmittance.

When the first region 301 and the third region 303 adopt high reflection mirrors, reflection of the echo light is facilitated, and the intensity of the echo signal is improved. Preferably, the reflectivity of the high reflectivity mirror is greater than 99.5%.

Specifically, as shown in fig. 7, the light splitting device 300 may be formed by plating a circular high reflection film 330 and a ring-shaped high reflection film 340 on one surface of a substrate 310 (which may be made of optical glass or light-transmitting plastic, etc.) from the middle to the outer edge. The circular high reflective film 330 and the light-transmitting carrier corresponding thereto together form the first region 301 described above; the light-transmitting carrier between the circular high-reflection film 330 and the annular high-reflection film 340 forms a second region 302 for transmitting the emitted light to the target 10; the annular high-reflection film 340 and the light-transmitting carrier corresponding thereto together constitute the third region 303 described above.

When the first region 301 and the third region 303 adopt a transmissive mirror with a reflectance greater than the transmittance (specifically, the transmissive mirror may be manufactured by replacing the circular high reflection film 330 and the annular high reflection film 340 in the above-mentioned spectroscopic device 300 with reflective transmissive films), the first region 301 and the third region 303 can not only realize reflection of the echo light but also play a role in transmitting the emitted light to a certain extent, and improve the intensity of the emitted signal.

In some embodiments, the second region 302 is an annular light hole when the second region 302 transmits the emitted light to the target 10; alternatively, the second region 302 is an annular light-transmitting body.

In one embodiment, as shown in fig. 3-4 and 6-7, the second region 302 is elliptical in shape.

As shown in fig. 2 and 5, when the beam splitting device 300 is applied to a laser radar with coaxial transceiving, the incident angle of the emitted light projected onto the beam splitting device 300 is set at an acute angle (typically 45 °), and the second region 302 is designed to be elliptical and ring-shaped so as to better adapt to the shape of the circular light spot in the cross section of the emitted light.

In one embodiment, angle-selective transmission film 400 and angle-selective reflection film 500 each comprise multiple dielectric films, at least two of which have different optical refractive indices.

Angle selectionBoth the transmission selective film 400 and the angle selective reflection film 500 may be realized by a multi-layered structure. Specifically, the angle-selective transmission film 400 and the angle-selective reflection film 500 each have TiO ₂ Layer and MgF ₂ A multilayer structure formed by alternately laminating layers.

The angle of the boundary between transmissive and non-transmissive can be adjusted by setting the material (refractive index) and the thickness of the layer constituting both the angle-selective transmission film 400 and the angle-selective reflection film 500.

In one embodiment, as shown in fig. 8, the laser receiving device 200 includes a receiving mirror set 210, a detector 220, and an angle-selective transmission film 230. The receiving lens group 210 includes a plurality of lenses arranged in order from the object side to the image side. The detector 220 is disposed at the image side of the receiving lens set 210, and the detector 220 is used for receiving the reflected light. The angle-selective transmission film 230 is disposed on a lens on the object side and/or a lens on the image side in the receiving lens set 210, and the angle-selective transmission film 230 is configured to transmit light having an incident angle within a divergence angle range of the echo light and is configured to block light having an incident angle outside the divergence angle range of the echo light.

By providing the angle selective transmission film 230 on the lens located on the object side and/or on the lens located on the image side in the receiving lens group 210, light rays with different incident angles can be selected by the angle selective transmission film 230, so that light rays meeting the incident angle requirement (the incident angle is within the divergence angle range of the echo light) can transmit, while light rays not meeting the incident requirement (light rays with the incident angle outside the divergence angle range of the echo light) can be blocked, and stray light entering the detector 220 can be effectively reduced. Since the angle-selective transmission film 230 is provided on the lens in the reception mirror group 210, miniaturization and assembly of the laser radar are facilitated.

The receiving lens group 210 is an important optical component in the laser receiving device 200, and is mainly used for converging the echo light formed after being reflected from the target object 10. The receiving lens group 210 is typically a combination of multiple lenses (including positive focal length lenses, negative focal length lenses). It is understood that the object side refers to the side on which the echo light is incident, and the image side refers to the side on which the echo light is emitted.

The detector 220 may be a PIN photodiode (PIN diode), an avalanche photodiode (Avalanche Photo Diode, APD), a single photon avalanche diode (Single Photon Avalanche Diode, SPAD), a Multi-pixel photon counter (Multi-Pixel Photon Counter, MPPC), a silicon photomultiplier (Silicon photo multiplier, siPM), or the like.

It should be noted that, the principle of the angle selective transmission film 230 is similar to that of the angle selective transmission film 400 described above, and will not be described here again.

In some embodiments, as shown in fig. 1-2, 5 and 9-10, the laser radar further includes a turning mirror 600, and the beam-splitter emitted light is reflected by the turning mirror 600 and exits to the three-dimensional space, and the beam-splitter reflected echo light is received by the laser receiving device 200.

Specifically, the turning mirror 600 is located between the beam splitting device 300 and the light outlet of the laser radar, and is used for implementing scanning on the target object 10 in the three-dimensional space.

In some specific embodiments, as shown in fig. 9-10, the surface of the turning mirror 600 is provided with an angle selective reflective film 700, and the angle selective reflective film 700 is used to reflect light rays having an incident angle within the range of the divergence angle of the echo light, and is used to transmit or absorb light rays having an incident angle outside the range of the divergence angle of the echo light.

Light rays with different incident angles are selected by the angle selective reflection film 700, so that light rays meeting the incident angle requirement can be reflected, and light rays not meeting the incident requirement are transmitted or absorbed, thereby further reducing stray light entering the detector 220.

It should be noted that, the principle of the angle selective reflection film 700 is similar to that of the angle selective reflection film 500 described above, and will not be described here again.

In some embodiments, as shown in fig. 10, the lidar further includes a filter cover 800, where the filter cover 800 is covered on the laser emitting device 100 and the laser receiving device 200, and the surface of the filter cover 800 is provided with an angle selective transmission film 900, where the angle selective transmission film 900 is used to transmit light rays having an incident angle within the divergence angle range of the echo light, and is used to block light rays having an incident angle outside the divergence angle range of the echo light.

The light rays with different incident angles are selected through the angle selective transmission film 900, so that the light rays meeting the incident angle requirement can transmit, and the light rays not meeting the incident requirement are blocked, so that stray light entering the detector 220 is further reduced.

It should be noted that, the principle of the angle selective transmission film 900 is similar to that of the angle selective transmission film 400 described above, and will not be described here again.

In addition, it can be understood that, in the lidar of this embodiment, by providing the angle selective transmission film 400 or the angle selective reflection film 500 on another lens (lens or reflector), the reflectivity or the transmissivity of the angle coating film of the lens can be controlled so as to be highly transparent or highly reflective in the range of the divergence angle of the effective light ray angle including the return light, and be highly reflective or highly transparent in other angles, so that the stray light cannot enter the receiving system through the lens.

The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

Claims

1. A lidar, comprising:

the laser receiving device is used for receiving the echo light;

2. The lidar of claim 1, wherein the first region and the third region are light holes when the first region transmits the echo light; or (b)

The first region is a light-transmitting body.

3. The lidar of claim 2, wherein the second region is a high-reflectivity mirror when the second region reflects the emitted light to the target; or (b)

4. The lidar of claim 1, wherein the first region and the third region are highly reflective mirrors when the first region and the third region reflect the echo light; or (b)

5. The lidar of claim 1, wherein the second region is elliptical in shape.

6. The lidar of claim 1, wherein the angle-selective transmission film and the angle-selective reflection film each comprise a multilayer dielectric film, and wherein at least two of the dielectric films have different optical refractive indices.

7. The lidar according to claim 1, wherein the laser receiving device comprises:

8. The lidar according to any of claims 1 to 7, further comprising a turning mirror, wherein the beam-splitter-acted emitted light is reflected by the turning mirror and exits to the three-dimensional space, and the reflected light is reflected by the turning mirror and received by the laser receiving device.

9. The lidar according to claim 8, wherein the surface of the turning mirror is provided with an angle-selective reflective film for reflecting light rays having an incidence angle within the range of the divergence angle of the echo light and for transmitting or absorbing light rays having an incidence angle outside the range of the divergence angle of the echo light.

10. The lidar according to any of claims 1 to 7, further comprising a filter cover provided over the laser emitting device and the laser receiving device, the surface of the filter cover being provided with an angle selective transmission film for transmitting light rays having an incidence angle within the range of the divergence angle of the return light and for blocking light rays having an incidence angle outside the range of the divergence angle of the return light.