CN115728742A

CN115728742A - Laser radar

Info

Publication number: CN115728742A
Application number: CN202111021783.8A
Authority: CN
Inventors: 李坤仪; 方志强
Original assignee: Suteng Innovation Technology Co Ltd
Current assignee: Suteng Innovation Technology Co Ltd
Priority date: 2021-09-01
Filing date: 2021-09-01
Publication date: 2023-03-03

Abstract

The invention is suitable for the technical field of laser radars, and provides a laser radar which comprises a transceiving module, a galvanometer and a double telecentric lens group which are sequentially arranged, wherein the double telecentric lens group comprises a positive lens and a negative lens which are arranged at intervals; the positive lens is arranged close to the transceiving module and is used for converging the light beam so as to reduce the diameter of the light beam; the negative lens is used for diverging the light beam to increase the emission angle of the light beam; the receiving and sending module is used for sending out a detection laser beam, and the detection laser beam can be emitted to a detection area through the vibrating mirror, the positive lens and the negative lens in sequence and then reflected by an object in the detection area to form a reflected laser beam; and the reflected laser beam can enter the transceiving module through the negative lens, the positive lens and the vibrating mirror in sequence. The laser radar provided by the invention reduces the diameter of the detection laser beam, increases the beam emitting angle of the detection laser beam, forms a larger scanning field angle, and simultaneously considers other requirements of the MEMS laser radar.

Description

Laser radar

Technical Field

The invention belongs to the technical field of laser radars, and particularly relates to a laser radar.

Background

At present, an MEMS (Micro-Electro-Mechanical System) laser radar has the requirement of a large field angle, but an MEMS galvanometer drives the galvanometer to rotate by means of two cantilevers of a fast shaft and a slow shaft, and cannot swing by a too large angle, so that the field of view of the MEMS laser radar can be increased only by adding modules, the field of view needs to be spliced in multiple fields of view, the System cost and the installation and adjustment difficulty can be increased, and the laser radar is large in size.

Disclosure of Invention

The invention aims to provide a laser radar, and aims to solve the technical problem that the laser radar in the prior art cannot simultaneously meet the requirements of large field angle, low cost, easiness in installation and adjustment, small size and the like.

The invention is realized in this way, a laser radar, including the transceiver module, reflector, galvanometer and pair of telecentric lens battery set that set up sequentially, the said pair of telecentric lens battery includes positive lens and negative lens set up at interval; the positive lens is arranged close to the transceiving module and is used for converging light beams so as to reduce the diameter of the light beams; the negative lens is used for diverging the light beam to increase the light beam emission angle;

the receiving and sending module is used for sending out a detection laser beam, and the detection laser beam can be emitted to a detection area through the vibrating mirror, the positive lens and the negative lens in sequence and then reflected by an object in the detection area to form a reflected laser beam; and the reflected laser beam can sequentially pass through the negative lens, the positive lens and the vibrating mirror to enter the transceiving module.

In an optional embodiment, the lidar further comprises a flat field lens located at the light-emitting side of the double telecentric lens group or between the galvanometer and the double telecentric lens group, and the flat field lens is used for correcting field distortion.

In an optional embodiment, the double telecentric lens group further includes a lens barrel, and the negative lens and the positive lens are both fixedly mounted in the lens barrel.

In an optional embodiment, the field flattening lens is embedded in the light outlet of the lens barrel.

In an optional embodiment, the lidar further comprises a base, and the transceiver module, the galvanometer and the double telecentric lens group are all fixedly mounted on the base.

In an optional embodiment, the lidar further comprises a housing, the housing alone or in combination with the base forms a containing cavity for containing the transceiver module, the galvanometer and the double telecentric lens group, the housing is provided with a window, and the field flattening lens is embedded in the window. I.e. a flat field lens, is used as a window pane.

In an optional embodiment, the lidar further comprises a mirror located between the transceiver module and the galvanometer, and an optical axis of the mirror is aligned with a center of the galvanometer.

In an alternative embodiment, the optical axes of the negative lens and the positive lens are respectively aligned with the center of the galvanometer.

In an optional embodiment, the galvanometer is a two-dimensional MEMS galvanometer;

the negative lens is a plano-concave lens, and the plane of the plano-concave lens is located on the side away from the positive lens.

In an optional embodiment, the transceiver module comprises a transmitting module, a collimating module and a receiving module;

the transmitting module is used for transmitting a detection laser beam; the collimation module is used for collimating the detection laser beam into a parallel laser beam and emitting the parallel laser beam to the vibrating mirror; the receiving module is used for receiving the reflected laser beam.

Compared with the prior art, the invention has the technical effects that: the laser radar provided by the embodiment of the invention is sequentially provided with the transceiving module, the vibrating mirror and the double telecentric lens group to form a coaxial light path for transmitting and receiving, and a detection laser beam emitted by the transceiving module is sequentially irradiated onto an object in a detection area through the vibrating mirror and the double telecentric lens group, and then is reflected by the object, passes through the double telecentric lens group and the vibrating mirror and returns to the transceiving module. Wherein, positive lens among the two telecentric lens group can play the effect of convergent light beam to reduce the diameter of surveying laser beam, negative lens then can improve the light beam divergence degree of surveying laser beam, cooperate with positive lens and can make laser radar form clear and bigger scanning field angle.

In addition, the laser radar provided by the embodiment of the invention has the advantages of simple structure, low cost, small volume and convenience in assembly and debugging, and takes various requirements of the existing MEMS laser radar into consideration, but the laser radar provided by the embodiment of the invention is not limited to the MEMS laser radar and is also suitable for laser radars of other models.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention or in the description of the prior art will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic optical path diagram of a laser radar according to an embodiment of the present invention, in which solid arrows indicate incident optical paths, and dashed arrows indicate reflected optical paths;

fig. 2 is a schematic optical path diagram of a laser radar according to another embodiment of the present invention, in which solid arrows indicate incident optical paths, and dashed arrows indicate reflected optical paths;

fig. 3 is a schematic diagram illustrating a distribution of beams in a use state of the laser radar according to an embodiment of the present invention, where the transceiver module is not shown;

fig. 4 is a schematic diagram of a distribution of beams in a use state of the laser radar according to another embodiment of the present invention, in which the transceiver module is not shown;

FIG. 5 is a schematic view of a scanning area corresponding to the lidar shown in FIG. 3;

FIG. 6 is a schematic view of a corresponding scan region of the lidar shown in FIG. 4;

fig. 7 is a schematic diagram illustrating a distribution of beams in a use state of a laser radar according to another embodiment of the present invention, in which a transceiver module is not shown;

fig. 8 is a schematic structural diagram of a lidar according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of the internal structure of a double telecentric lens assembly used in one embodiment of the present invention;

FIG. 10 is a schematic diagram of the internal structure of a double telecentric lens group used in another embodiment of the invention;

fig. 11 is a schematic diagram of an internal structure of a lidar according to another embodiment of the present invention.

Description of reference numerals:

100. a transceiver module; 110. a transmitting module; 120. a collimation module; 130. a receiving module; 140. a beam splitting module; 200. a mirror; 300. a galvanometer; 400. a double telecentric lens group; 410. a positive lens; 420. a negative lens; 430. a lens barrel; 431. a first end; 432. a second end; 440. a gasket; 450. pressing a ring; 500. detecting an object within the area; 600. a flat field lens; 700. a base; 800. a housing.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

In the description of the present invention, 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, indicate orientations or positional relationships based on the orientations or positional relationships illustrated in the drawings, and are used merely for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

Referring to fig. 1 to 3, in an embodiment of the present invention, a laser radar is provided, which includes a transceiver module 100, a galvanometer 300, and a double telecentric lens assembly 400 sequentially disposed.

The transceiver module 100 is used for emitting a detection laser beam and receiving a reflected laser beam. Specifically, the transceiver module 100 at least includes a transmitting module 110 for transmitting the detection laser beam and a receiving module 130 for receiving the reflected laser beam, and the optical path of the transmitting module 110 and the optical path of the receiving module 130 may be coaxially arranged. Optionally, the launch module 110 comprises at least one laser source. When the emitting module 110 includes a plurality of laser sources, the plurality of laser sources are arranged in one or two dimensions, and in practical applications, the laser sources may be continuous light sources, such as Light Emitting Diodes (LEDs), or pulsed light sources, such as Laser Diodes (LDs), which is not limited in this embodiment. Optionally, the receiving module 130 is configured to receive a reflected laser beam reflected by the galvanometer 300, and process the received reflected laser beam to obtain information about the object 500 in the detection area; the receiving module 130 includes a receiver for receiving the reflected laser beam and converting the reflected laser beam into an electrical signal. The number of the receivers can be one or multiple, and the multiple receivers are arranged into an array; the receiver may be one or more combinations of photodiodes, avalanche diodes, APDs, silicon photomultipliers, sipms, and the like.

The galvanometer 300 may be a one-dimensional MEMS, a two-dimensional MEMS, or a combination thereof, and is configured to change a direction of the detection laser beam to emit the detection laser beam to the double telecentric lens group 400, and also to change a direction of the reflected laser beam to emit the reflected laser beam to the transceiver module 100.

The double telecentric lens group 400 comprises a positive lens 410 and a negative lens 420 which are arranged at intervals. The positive lens 410 serves to condense the light beam to reduce the beam diameter. The negative lens 420 serves to diverge the light beam to increase the light beam emission angle. Specifically, one or more positive lenses 410 and negative lenses 420 may be disposed in the double telecentric lens group 400, and the types of the positive lenses 410 and the negative lenses 420 may be selected according to the usage requirement, which is not limited herein. The positive lens 410 is disposed near the transceiver module 100, and the negative lens 420 is disposed near the galvanometer 300, that is, the negative lens 420 is disposed between the positive lens 410 and the galvanometer 300.

The application principle of the laser radar provided by the embodiment of the invention is as follows:

incident light path: the transceiver module 100 emits a detection laser beam, which is reflected by the galvanometer 300 to reach the double telecentric lens assembly 400, then converged by the positive lens 410 and diverged by the negative lens 420 in the double telecentric lens assembly 400 to reach a detection area, and finally reflected by an object in the detection area to form a reflected laser beam.

Reflection light path: the reflected laser beam is converged by the negative lens 420 and diverged by the positive lens 410 in the double telecentric lens assembly 400, and then reflected to the galvanometer 300, and then reflected back to the transceiving module 100 by the galvanometer 300, and the transceiving module 100 receives the reflected laser beam and analyzes the reflected laser beam to obtain the object information in the detection area.

The laser radar provided by the embodiment of the invention is sequentially provided with the transceiving module 100, the vibrating mirror 300 and the double telecentric lens assembly 400 to form a coaxial light path for transmitting and receiving, and a detection laser beam emitted by the transceiving module 100 is irradiated onto an object 500 in a detection area through the vibrating mirror 300 and the double telecentric lens assembly 400 in sequence, and then is reflected by the object and returns to the transceiving module 100 through the double telecentric lens assembly 400 and the vibrating mirror 300. The positive lens 410 in the double telecentric lens assembly 400 can converge the light beam to reduce the diameter of the detection laser beam, the negative lens 420 can improve the light beam divergence degree of the detection laser beam, and the laser radar can form a clear and larger scanning field angle by matching with the positive lens 410.

Due to the field curvature, the scanning range of the angular domain corresponding to the scanning angle of the laser radar is greatly distorted. To address this problem, in an alternative embodiment, as shown in fig. 4, the lidar further includes a field flattening lens 600 located on the light exit side of the double telecentric lens group 400 or between the galvanometer 300 and the double telecentric lens group 400. The flat field lens 600 is used to correct field distortion so that the lidar obtains a small distorted scanned field of view.

To illustrate this effect, for example, in a specific embodiment, the beam diameter of the detection laser beam emitted by the transceiver module 100 is 5mm, the mechanical scanning angle of the galvanometer 300 in the horizontal and vertical directions is ± 5 °, and the scanning area of the detection laser beam is 20 × 20 ° after passing through the galvanometer 300; then the emission angle of the detection laser beam is increased after the detection laser beam passes through the positive lens 410 and the negative lens 420 in the double telecentric lens group 400. By designing a proper structure of the double telecentric lens group 400, the scanning area is increased to 80 × 80 °, the field angle is increased to 4 times of the original field angle, and the angular resolution is reduced to 1/4 of the original field angle.

However, due to the curvature of field of the lens, the larger the scanning angle is, and the more serious the final emergent angle distortion is. When the galvanometer 300 scans to a horizontal or vertical 5-degree position, the horizontal and vertical central field scanning ranges meet the requirement of 80-80 degrees, namely, the maximum emergent angle is 40 degrees. However, when the scanning angle of the galvanometer 300 is 5 horizontally and vertically, the edge ray angle reaches 52 degrees, i.e., the edge scan area reaches 114 degrees, as shown in FIG. 5. Therefore, the point cloud of the radar is seriously distorted by more than 28 percent.

At this time, if the flat-field lens 600 is added to the laser radar, the distortion of the final radar scanning area can be effectively reduced, and the distortion of the entire field of view can be corrected to be less than 5%, as shown in fig. 6. And the design of the flat field lens 600 can be adjusted so that the final field of view is a standard 45 x 45 rectangular field of view.

Referring to fig. 7, in an alternative embodiment, the lidar further includes a mirror 200 disposed between the transceiver module 100 and the galvanometer 300. The reflecting mirror 200 is used for reflecting the detection laser beam emitted by the transceiver module 100 to the galvanometer 300, or reflecting the reflected laser beam reflected by the galvanometer 300 to the transceiver module 100. The setting of speculum 200 makes the light path direction adjust as required to make the optical axis of receiving and dispatching module 100 and the center of mirror 300 that shakes can not be on same straight line, thereby make each part in the laser radar compacter, help reducing the volume of laser radar.

Since the galvanometer 300 is deflected, in order to ensure that the detection laser beam in the incident light path can always be reflected by the reflecting mirror 200 onto the galvanometer 300, in an alternative embodiment, the optical axis of the reflecting mirror 200 is aligned with the center of the galvanometer 300.

Similarly, since the galvanometer 300 is deflected, in order to ensure that the reflected laser beam in the reflected light path can be incident on the galvanometer 300 through the positive lens 410 or the negative lens 420, in another alternative embodiment, the optical axes of the negative lens 420 and the positive lens 410 are respectively aligned with the center of the galvanometer 300.

The galvanometer 300 is a two-dimensional MEMS galvanometer. The galvanometer 300 is capable of rotational scanning at a mechanical angle in both the horizontal and vertical directions. The detection laser beam emitted by the transceiver module 100 passes through the two-dimensional MEMS galvanometer and then is scanned in a line scanning manner, the horizontal angle and the vertical angle of the scanning field of view are determined by the scanning mechanical angle of the two-dimensional MEMS galvanometer, and the field of view position is determined by the emitting position of the detection laser beam emitted by the transceiver module 100.

In an alternative embodiment, as shown in fig. 1, the transceiver module 100 includes a transmitter module 110, a collimator module 120, and a receiver module 130. The emitting module 110 is used for emitting a detection laser beam. The collimating module 120 is used for collimating the detection laser beam into a parallel laser beam and emitting the parallel laser beam to the galvanometer 300. The receiving module 130 is used for receiving the reflected laser beam deflected by the collimating module 120. Optionally, the emitting module 110 includes a laser source for emitting the emitted laser. In practical application, the laser source may be a continuous light emitting source, such as a light emitting diode LED, or a pulsed light emitting source, such as a laser diode LD, which is not specifically limited in this embodiment. Optionally, the collimating module 120 includes at least one collimating mirror, which may be specifically configured according to the usage requirement, and is not limited herein. Optionally, the receiving module 130 is configured to receive the reflected laser deflected by the beam splitting module 140, and process the received reflected laser, so as to obtain information about the object 500 in the detection area; the receiving module 130 includes a receiver for receiving the reflected laser and converting the reflected laser into an electrical signal. The number of the receivers can be one or multiple, and the receivers are arranged into an array; the receiver may be one or more combinations of photodiodes, avalanche diodes, APDs, silicon photomultipliers, sipms, and the like.

In another alternative embodiment, as shown in fig. 2, the transceiver module 100 includes a transmitter module 110, a splitter module 140, and a receiver module 130. The emitting module 110 is used for emitting a detection laser beam. The beam splitting module 140 is used for passing the detection laser beam and directing to the galvanometer 300, and is also used for deflecting the received reflected laser beam to the receiving module 130. The receiving module 130 is used for receiving the reflected laser deflected by the beam splitting module 140. The structures of the transmitting module 110 and the receiving module 130 in this embodiment may be the same as the structures of the transmitting module 110 and the receiving module 130 in the previous embodiment, and as above, the description is omitted here. The beam splitting module 140 includes a beam splitting assembly, which may be one or a combination of a perforated mirror 200, a polarization beam splitter PBS, a polarization beam splitter, and the like, and is not specifically limited in this application.

In a specific embodiment, as shown in fig. 8 and 9, the double telecentric lens group 400 further includes a lens barrel 430, and the negative lens 420 and the positive lens 410 are respectively fixedly mounted in the lens barrel 430. Specifically, the positive lens 410 and the negative lens 420 can be respectively fixed in the lens barrel 430 by means of insertion, adhesive bonding, clamping, and the like. Thus, the double telecentric lens group 400 forms a whole body for easy movement.

More specifically, the positive lens 410 is located at a first end 431 of the lens barrel 430, the negative lens 420 is located at a second end 432 of the lens barrel 430, the first end 431 is an incident end of the detection laser beam, and the second end 432 is an exit end of the detection laser beam. With such an arrangement, the detection laser beam is converged and then emitted, so that the volume of the lens barrel 430 is small, and the floor area thereof is reduced. In an alternative embodiment, as shown in fig. 10, the field flattening lens 600 is fitted into the light exit of the lens barrel 430. Specifically, the flat field lens 600 may be fixed to the light exit of the lens barrel 430 by means of insertion, bonding, clamping, and the like, so as to be combined with the double telecentric lens assembly 400 into a whole, thereby facilitating subsequent assembly or movement of the laser radar.

In an alternative embodiment, as shown in fig. 9 and 10, a gasket 440 is disposed between every two adjacent lenses in the lens barrel 430 to realize the interval arrangement of the two adjacent lenses, so as to avoid collision between the two adjacent lenses and influence on the use effect.

More specifically, as shown in fig. 9 and 10, a pressing ring 450 is disposed at an end of the lens barrel 430, and the pressing ring 450 is used to cooperate with a corresponding washer 440 to press and limit the lens at the outer end to the end of the lens barrel 430.

In a specific embodiment, as shown in fig. 8, the lidar further includes a base 700, and the transceiver module 100, the galvanometer 300, and the double telecentric lens assembly 400 are all fixedly mounted on the base 700. Specifically, the transceiver module 100, the galvanometer 300, and the double telecentric lens assembly 400 may be respectively fixed on the base 700 by plugging, gluing, and the like. And when the laser radar includes the reflecting mirror 200, the reflecting mirror 200 is fixedly installed on the base 700. Thus, the lidar forms an integral device which is convenient to move.

In another alternative embodiment, as shown in fig. 11, the lidar further includes a housing 800, and the housing 800 alone or in combination with the base 700 defines a cavity for accommodating the transceiver module 100, the galvanometer 300, and the double telecentric lens assembly 400. Specifically, the housing 800 may be covered on the base 700, as shown in fig. 11, to enclose the transceiving module 100, the galvanometer 300, and the double telecentric lens assembly 400 therein; alternatively, the housing 800 and the base 700 may be separately provided, and the base 700 may be placed in the housing 800. The housing 800 is provided with a window, and the field flattener lens 600 is embedded in the window, that is, the field flattener lens 600 is used as a window sheet. In this form, the field flattener lens 600 and the lens barrel 430 can be separately disposed, facilitating their respective assembly and maintenance.

In one specific embodiment, as shown in fig. 9 and 10, the negative lens 420 is a plano-concave lens, and the plane of the plano-concave lens is located on the side facing away from the positive lens 410. Thus, the plane of the negative lens 420 is located at the outer end of the lens barrel 430, which is convenient for assembly and maintenance.

The foregoing is considered as illustrative only of the preferred embodiments of the invention, and is presented merely for purposes of illustration and description of the principles of the invention and is not intended to limit the scope of the invention in any way. Any modifications, equivalents and improvements made within the spirit and principles of the invention and other embodiments of the invention without the exercise of inventive faculty will be appreciated by those skilled in the art and are intended to be included within the scope of the invention.

Claims

1. The laser radar is characterized by comprising a receiving and transmitting module, a galvanometer and a double telecentric lens group which are arranged in sequence, wherein the double telecentric lens group comprises a positive lens and a negative lens which are arranged at intervals; the positive lens is arranged close to the transceiving module and is used for converging light beams so as to reduce the diameter of the light beams; the negative lens is used for diverging the light beam to increase the light beam emission angle;

the receiving and sending module is used for sending out a detection laser beam, and the detection laser beam can be emitted to a detection area through the vibrating mirror, the positive lens and the negative lens in sequence and then reflected by an object in the detection area to form a reflected laser beam; and the reflected laser beam can enter the transceiving module through the negative lens, the positive lens and the vibrating mirror in sequence.

2. The lidar of claim 1, further comprising a field flattening lens positioned at an exit side of the double telecentric lens group or between the galvanometer and the double telecentric lens group, the field flattening lens configured to correct for field distortion.

3. The lidar of claim 2, wherein the double telecentric lens group further comprises a barrel, and wherein the negative lens and the positive lens are both fixedly mounted within the barrel.

4. The lidar of claim 3, wherein the field flattening lens is fitted into a light exit port of the lens barrel.

5. The lidar of claim 3, wherein the lidar further comprises a base, and wherein the transceiver module, the galvanometer, and the double telecentric lens assembly are fixedly mounted on the base.

6. The lidar of claim 5, further comprising a housing, wherein the housing alone or in combination with the base defines a receiving cavity for receiving the transceiver module, the galvanometer, and the double telecentric lens assembly, and the housing defines a window, and the field flattener lens is embedded in the window.

7. The lidar of any of claims 1-6, further comprising a mirror positioned between the transceiver module and the galvanometer, an optical axis of the mirror being aligned with a center of the galvanometer.

8. The lidar of any of claims 1-6, wherein optical axes of the negative lens and the positive lens are each aligned with a center of the galvanometer.

9. The lidar of any of claims 1-6, wherein said galvanometer is a two-dimensional MEMS galvanometer;

10. The lidar of any of claims 1-6, wherein the transceiver module comprises a transmit module, a collimation module, and a receive module;

the transmitting module is used for transmitting a detection laser beam; the collimation module is used for collimating the detection laser beam into a parallel laser beam and emitting the parallel laser beam to the galvanometer; the receiving module is used for receiving the reflected laser beam.