CN219758503U - Laser radar receiving end and laser radar - Google Patents

Abstract

The embodiment of the utility model provides a laser radar receiving end and a laser radar, and relates to the technical field of laser radars. The laser radar receiving end comprises a beam splitting prism and at least two detectors. Because of the plurality of detectors, the beam splitter prism is used for splitting the echo beam into light corresponding to the plurality of detectors, the light is respectively received by each detector, and each detector respectively processes each part of the original echo beam, thereby achieving higher resolution.

Description

Laser radar receiving end and laser radar

Technical Field

The utility model relates to the technical field of laser radars, in particular to a laser radar receiving end and a laser radar.

Background

Along with the rapid development of automatic driving technology, sensors for sensing environmental information are increasingly widely applied to automobiles, and the types of the sensors include vision sensors, distance sensors and the like, and particularly include image sensors, infrared night vision sensors, ultrasonic radars, millimeter wave radars, laser radars and the like. The laser radar has the advantages of accurate target identification, interference resistance, high stability and the like, so that the laser radar can be rapidly developed in the vehicle-mounted sensor. The laser radar generally comprises a laser transmitting end and a laser receiving end, and the resolution of the receiving end determines the resolution of the cloud image of the target point, so as to determine the detection precision of the laser radar.

The utility model patent application with publication number of CN114646939A discloses a laser radar receiving system, which comprises a positive lens group, a negative cylindrical lens and a photoelectric detector which are sequentially arranged, wherein the positive lens group is configured to focus signal light returned by a target object; the plane of the negative cylindrical lens faces the positive lens group, the concave surface of the negative cylindrical lens faces the photoelectric detector, and the negative cylindrical lens is configured to receive light rays focused by the positive lens group; the photodetector is configured to receive light rays exiting through the negative cylindrical lens.

The laser radar receiving system is characterized in that one receiving lens corresponds to one photoelectric detector, and the resolution ratio is low.

Therefore, how to improve the resolution of the receiving end of the laser radar and the resolution of the point cloud image of the laser radar and the detection precision are needed to be solved.

Disclosure of Invention

The utility model aims to provide a laser radar receiving end and a laser radar, which are used for solving the technical problem of how to improve detection precision in the prior art.

In order to achieve the above purpose, the following technical scheme is adopted in the embodiment of the utility model.

In a first aspect, an embodiment of the present utility model provides a lidar receiving end, which includes a beam splitting prism and at least two detectors, where the beam splitting prism is located at one side of a beam receiving surface of the at least two detectors.

The beam splitting prism is used for splitting an incident echo beam into a preset number of emergent echo beams, so that each detector receives the emergent echo beams representing different parts of the incident echo beam, and the number of the emergent echo beams is equal to that of the detectors.

Compared with the prior art, the utility model has the following beneficial effects:

because of the plurality of detectors, the beam splitter prism is used for splitting the echo beam into light corresponding to the plurality of detectors, the light is respectively received by each detector, and each detector respectively processes each part of the original echo beam, thereby achieving higher resolution.

Optionally, at least one of the incident surface or the emergent surface of the beam-splitting prism is in a concave angle shape. For example, the incidence surface of the beam splitter prism is concave, and the emergent surface is plane or convex. The incident surface is in a shape formed by splicing planes, the emergent surface is also free of curved surfaces, and the light path can be emitted only through plane refraction, so that the emitted light beams are more regular.

Optionally, the beam splitting prism is formed by splicing two right trapezoid cylindrical prisms; and the short side planes of the right trapezoid are attached.

Optionally, the beam-splitting prism is formed by splicing two parallelogram cylindrical prisms; the bottom side planes of the parallelograms are attached, the obtuse angle hypotenuse is an incident plane, and the acute angle hypotenuse is an emergent plane.

Optionally, the number of the detectors is two, and the two detectors and the beam splitting prism are symmetrically arranged.

Optionally, the beam receiving surfaces of all the detectors are located on the same plane.

When the light beam receiving surfaces of all the detectors are positioned on the same plane, the detectors are convenient to be arranged on the same circuit board.

Optionally, the shape of the beam splitting prism is symmetrical according to a middle plane, and the detectors are symmetrically arranged according to the middle plane.

Optionally, the laser radar receiving end further includes a lens group, the lens group is located at one side of the incident surface of the beam splitting prism, and a main optical axis of the lens group is located on the middle surface of the beam splitting prism.

In a second aspect, an embodiment of the present utility model provides a lidar, including the lidar receiving end of the first aspect.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present utility model and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic diagram of a receiving end of a lidar according to an embodiment of the present utility model;

FIG. 2 is a schematic view of a beam-splitting prism with planar incident and exit surfaces according to an embodiment of the present utility model;

fig. 3 is a schematic view of a beam-splitting prism formed by splicing two right trapezoid cylindrical prisms according to an embodiment of the present utility model;

fig. 4 is a schematic view of a beam-splitting prism formed by splicing two identical right trapezoid cylindrical prisms according to an embodiment of the present utility model;

fig. 5 is a schematic view of a beam-splitting prism formed by splicing two parallelogram cylindrical prisms according to an embodiment of the present utility model;

FIG. 6 is a schematic view of a beam-splitting prism formed by splicing two identical parallelogram cylindrical prisms according to an embodiment of the present utility model;

fig. 7 is a schematic diagram of a laser radar receiving end of a two-stage parallelogram cylindrical prism according to an embodiment of the present utility model;

fig. 8 is a schematic diagram of a receiving end of a lidar with a lens assembly according to an embodiment of the present utility model;

fig. 9 is a schematic diagram of a laser radar receiving end of a splitting prism formed by splicing two right trapezoid cylindrical prisms instead of the splitting prism in fig. 8 according to an embodiment of the present utility model;

fig. 10 is a schematic diagram of main design parameters of a splitting prism formed by splicing parallelogram cylindrical prisms and a splitting prism formed by splicing right trapezoid cylindrical prisms according to an embodiment of the present utility model.

Reference numerals illustrate:

101-lens group

102-beam-splitting prism

1021-plane number one

1022-second plane

1023-third plane

1024-fourth plane

11-prism

12-prism No. two

1031-first detector

1032-second detector

1033-third detector

1034-fourth detector

104 echo beam of target

Echo beam processed by 105-lens group

1061-echo Beam

1062-echo beam number two

202-right trapezoid spliced beam splitter prism

2061-third echo Beam

2062-fourth echo Beam

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present utility model more apparent, the technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model, and the described embodiments are some embodiments of the present utility model, but not all embodiments of the present utility model. The components of the embodiments of the present utility model generally described in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the utility model, as presented in the figures, is not intended to limit the scope of the utility model, as claimed, but is merely representative of selected embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model. The following embodiments and features of the embodiments may be combined with each other without conflict.

The existing laser radar receiving system is characterized in that one receiving lens corresponds to one photoelectric detector, and the whole echo beam is processed by only one detector, so that the resolution ratio is low.

If the echo received by one receiving lens is directly incident on a plurality of closely arranged detectors, the resolution of the receiving end can be improved, but the closely arranged mode of the detectors can cause crosstalk signals among the detectors to influence detection, and even if the echo is closely arranged, a larger part of the echo is incident on the gap of the detectors, so that the energy loss and waste of echo light signals are caused.

In order to overcome the above problems, referring to fig. 1, an embodiment of the present utility model provides a receiving end of a laser radar, which includes a beam splitting prism 102 and at least two detectors, in the drawing, a first detector 1031 and a second detector 1032, where the beam splitting prism 102 is located at one side of a beam receiving surface of the at least two detectors. The diagonally shaded left side of the detector in the figure represents the receive beam plane, i.e. the receive beam plane is the plane in the figure where the left line extends in a direction perpendicular to the plane of the paper.

The shading in the figure is an indication of the echo beam, the propagation direction of the echo beam is from left to right, the echo beam with the left side being the incident echo beam, and the two narrower echo beams on the right side being the emergent echo beams.

The beam splitting prism 102 is used to split the incoming echo beam into a number of outgoing echo beams of detectors such that each detector receives an outgoing echo beam representing a different portion of the incoming echo beam. In the example of fig. 1, an incident echo beam is split into two outgoing echo beams, which represent the upper half and the lower half of the incident echo beam.

Compared with the prior art, the utility model has the following beneficial effects:

because the laser radar receiving end is provided with a plurality of detectors, the beam splitter prism is used for dividing the echo beam into light corresponding to the plurality of detectors, the light is respectively received by each detector, and each detector respectively processes each part of the original echo beam, thereby achieving higher resolution and higher detection precision.

Moreover, the beam splitting prism can be designed, and the emission position and the emission direction of the split light can be further designed, so that the beam splitting prism can split the echo light beams to emit the light with a longer distance, the detectors do not need to be closely arranged, the light can be prevented from being emitted into gaps between the detectors through the design of the beam splitting prism, and the energy waste of echo light signals caused by the gaps of the detectors is avoided, namely, the echo light beams received by the detectors do not have energy loss.

The distance between the detectors and the emergent light of the beam splitting prism can be designed to be far apart, so that no optical crosstalk exists between the detectors.

For the beam splitter prism, at least one of the incident surface or the emergent surface is concave and angular, so that the echo beam can be split into scattered beams. The concave angle can be seen in fig. 2, in which the incident surface of the beam splitter prism 102 is concave, and the emergent surface is planar or convex. The concave included angle is the included angle that the surface of the object is concave inwards, and the section shape of the object along the concave part is a concave included angle.

In fig. 2, the incident surface of the beam splitter prism 102 has a shape formed by two planes, i.e., a first plane 1021 and a second plane 1022. The angle between plane one 1021 and plane two 1022 is a concave angle α.

Light is incident from the incident surface, that is, the echo beam is divided into an echo beam incident from the first plane 1021 and an echo beam incident from the second plane 1022.

In fig. 2, the exit surface of the dichroic prism 102 is also in a shape formed by two planes, which are a third plane 1023 and a fourth plane 1024, respectively. The angle between plane No. 1023 and plane No. 1024 is convex angle β.

An echo beam incident from the first plane 1021 is emitted from the third plane 1023; the echo beam incident on the second plane 1022 is emitted from the fourth plane 1024.

The relationship between the included angles α and β can be divided into the following three cases: when alpha is smaller than beta, the emergent light diverges outwards; when alpha=beta, the emergent light is parallel; when alpha is larger than beta, the emergent light is converged inwards. Only the alpha is required to be ensured to be small enough, the echo beam is separated far enough in the prism, and the echo beam can be emitted to different separated detectors.

For the beam splitting prism 102, the process quality of the entrance face, exit face and the portion through which the echo beam passes is the most critical, and the accuracy of the other edge faces is of minor importance.

The incident surface and the emergent surface are arranged to be plane, so that unnecessary deformation, amplification or shrinkage of the imaging pattern of the echo beam can be prevented, and the design is simplified. If convergence or divergence is required, the incident surface and the emergent surface can be provided in the form of convex lenses, concave lenses and the like.

To simplify the process, the component light prisms 102 may be spliced by groups of prisms. The manufacture of each prism is easier than the direct processing of the shape of the integral beam splitting prism, and better precision can be achieved.

Fig. 3 shows a splitting prism 102 formed by splicing two right trapezoid prism columns, which are a first prism 11 and a second prism 12 respectively; the overall shape of the right trapezoid columnar prism is a columnar shape formed by extending the right trapezoid along the direction perpendicular to the paper surface. The short side planes of the right trapezoid are attached, the hypotenuse plane is an incident plane, and the right-angle side plane is an emergent plane. Each right trapezoid column prism is easier to manufacture than the shape of the whole beam splitting prism, and better precision can be achieved.

The first prism 11 and the second prism 12 in fig. 3 may have different sizes and shapes, and may have an effect of dividing the echo beam into two beams for emission, and may be finally received by the first detector 1031 and the second detector 1032.

As shown in fig. 4, the size and shape of the first prism 11 and the second prism 12 may be the same, that is, the same prism produced by using the complete process is used as the first prism 11 and the second prism 12, which further simplifies the process flow, and makes the product symmetrical and attractive, that is, the shape of the splitting prism 102 is symmetrical according to a middle plane, and the middle plane is a plane in which the short side of the trapezoid in fig. 4 extends perpendicular to the paper surface.

In order not to change the direction of the outgoing light, each outgoing surface may be parallel to each incoming surface, and the first plane 1021 and the second plane 1022 may be provided to be parallel, and the third plane 1023 and the fourth plane 1024 may be provided to be parallel, that is, α=β.

As shown in fig. 5, the beam-splitting prism may be further configured by splicing two parallelogram cylindrical prisms, that is, the first prism 11 and the second prism 12 may be parallelogram cylindrical prisms; the overall shape of the parallelogram-shaped cylindrical prism is a cylinder formed by extending the parallelogram along the direction perpendicular to the paper surface. The bottom side planes of the parallelograms are attached, the obtuse angle hypotenuse is an incident plane, and the acute angle hypotenuse is an emergent plane.

The first prism 11 and the second prism 12 in fig. 5 may have different sizes and shapes, and may have an effect of dividing the echo beam into two beams for emission, and may be finally received by the first detector 1031 and the second detector 1032.

As shown in fig. 6, the first prism 11 and the second prism 12 may be parallelogram cylindrical prisms with the same size and shape, that is, the same prisms produced by using the complete process are used as the first prism 11 and the second prism 12, so that the process flow is further simplified, and the two detectors and the beam-splitting prism are symmetrically arranged in the figure, so that the product is symmetrical and attractive.

In fig. 6 is shown an embodiment with a number of detectors of 2, which also makes it possible to divide the echo beam into more beams.

Referring to fig. 6, in a space rectangular coordinate system, light propagates along the z direction, the shape of the cross section of the beam splitter prism in the xOz plane is shown in fig. 6, and it can be seen that the light is divided into two upper and lower beams, and if the shape of the cross section in the yOz plane is also shown in fig. 6, the light is divided into two left and right beams, and is divided into four beams of upper left, lower left, upper right and lower right, so that the resolution can be further improved.

Or a multi-stage beam splitter prism may be provided, as shown in fig. 7, where two stages are provided, and each stage splits a light beam into two beams, and then into 4 beams, corresponding to four detectors: the first detector 1031, the second detector 1032, the third detector 1033, and the fourth detector 1034 also have the effect of improving the resolution.

When dividing into more beams, the initial echo beam energy is constant, and dividing into more beams may result in energy reduction, for example, dividing into 4 beams with about 1/4 energy per beam, and dividing into more beams is detrimental to the reception of the detector.

In order to make the energy of emergent light higher and improve the light transmittance, the coating treatment of the beam splitting prism can be carried out, so that the light transmittance of the echo light beam reaches 98%.

In fig. 7, the beam receiving surfaces of all the detectors are located on the same plane, and the detectors of the same type are used, so that all the detectors are located on the same plane, and can be mounted on the same circuit board, thereby saving space and the number of parts.

The laser radar receiving end shown in fig. 8 further includes a lens group 101, where the lens group 101 is located on one side of the incident surface of the beam-splitting prism 102, and the main optical axis of the lens group 101 is located on the middle surface of the beam-splitting prism 102.

The laser radar detects the echo beam 104 of the target object, the echo beam 105 processed by the lens group is converged by the 101 laser radar receiving lens group 101, the echo beam 105 processed by the lens group is equally divided into a first echo beam 1061 and a second echo beam 1062 after being transmitted by the beam splitter prism 102, the two echo beams are respectively received by the two detectors 1031 and 1032, the process completes the detection of the echo of the target object by the two detectors, and therefore, compared with the prior art, the resolution of processing the laser radar point cloud image by one receiving lens corresponding to one detector is doubled.

The lens group 101 may include several lenses, of which only two are schematically shown in fig. 1. The detectors 1031 and 1032 may be any of the photodetectors APD, SIPM, SPAD, etc. The interval between the two detectors may be any value on the premise that the purpose of achieving spatial separation and preventing crosstalk is achieved.

Similarly, the laser radar receiving end shown in fig. 9 is replaced by the right trapezoid spliced beam splitter prism 202 in fig. 8, and the echo beam 105 processed by the lens group is equally divided into two echo beams, namely, the third echo beam 2061 and the fourth echo beam 2062 after being transmitted through the right trapezoid spliced beam splitter prism 202.

As shown in fig. 10, two right trapezoid prism-shaped prism-symmetrically spliced splitting prisms or parallelogram prism-shaped prism-symmetrically spliced splitting prisms are mainly designed with two parameters of an opening angle θ and a thickness t.

By designing 102 the materials of the beam splitting prism, the opening angle theta and the thickness t (the materials can be any optical glass materials, for example, H-K9L and H-ZF6 are used, the opening angle theta is 60 degrees, 70 degrees and 80 degrees, the thickness t is 5mm, 6mm and 7mm, the values are set to correspond to the interval indexes of the two echoes of 1061 and 1062), the interval between the two echo beams of 1061 and 1062 which are split can be enabled to be a certain value (for example, any value such as 2mm, 3mm and 4mm is achieved), the greater the interval is, the better the crosstalk prevention effect between detectors is, the interval between the two detectors of 1031 and 1032 is set to be equal to the interval between the two echo beams of 1061 and 1062, and the arrangement can enable the detectors to completely receive the echo beams and prevent the crosstalk between the two detectors in a space isolation mode.

Based on the above embodiments, the embodiments of the present utility model further provide a lidar and a vehicle, including the lidar receiving end.

The above-described embodiments of the apparatus and system are merely illustrative, and some or all of the modules may be selected according to actual needs to achieve the objectives of the present embodiment. Those of ordinary skill in the art will understand and implement the present utility model without undue burden.

The present utility model is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present utility model are intended to be included in the scope of the present utility model. Therefore, the protection scope of the present utility model should be subject to the protection scope of the claims.

Claims (10)

1. The laser radar receiving end is characterized by comprising a beam splitting prism and at least two detectors, wherein the beam splitting prism is positioned at one side of a beam receiving surface of the at least two detectors;

the beam splitting prism is used for splitting an incident echo beam into a preset number of emergent echo beams, so that each detector receives the emergent echo beams representing different parts of the incident echo beam; the number of the emergent echo beams is equal to the number of the detectors.

2. The lidar receiver of claim 1, wherein at least one of the entrance surface or the exit surface of the dichroic prism is concave.

3. The lidar receiver of claim 1, wherein the splitting prism is formed by splicing two right trapezoid cylindrical prisms; and the short side planes of the right trapezoid are attached.

4. The lidar receiver of claim 1, wherein the beam-splitting prism is formed by splicing two parallelogram cylindrical prisms; the bottom side planes of the parallelograms are attached, the obtuse angle hypotenuse is an incident plane, and the acute angle hypotenuse is an emergent plane.

5. The lidar receiver of claim 1, wherein the number of detectors is two, and the two detectors and the beam splitting prism are symmetrically arranged.

6. The lidar receiver of claim 1, wherein the receive beam planes of all the detectors are in the same plane.

7. The lidar receiver of claim 6, wherein all of the detectors are integrated on the same circuit board.

8. The lidar receiving terminal according to claim 1, wherein the beam splitting prism has a shape symmetrical with respect to a middle plane, and the detectors are symmetrically arranged with respect to the middle plane.

9. The lidar receiver of claim 8, further comprising a lens assembly positioned on a side of the entrance surface of the prism, wherein a principal optical axis of the lens assembly is positioned on a middle surface of the prism.

10. A lidar comprising a lidar receiver according to any of claims 1 to 9.