Optical system for realizing laser beam splitting of laser radar

Abstract

The utility model relates to an optical system for realizing laser beam splitting of a laser radar, and belongs to the field of laser radars. The optical system comprises a laser light source, a collimating lens group and a beam splitter, the laser light source is used for providing detection pulse signals; the collimating lens group is used for realizing collimation of emitted light beams; the beam splitter is used for splitting the collimated light beam into a plurality of laser beams in different directions; the incident plane of the beam splitter is a complete plane, and the emergent plane is made into zigzag refracting planes with different refracting angles through an optical micromachining process. According to the utility model, only one light source or a small number of laser light sources are needed, a plurality of laser beams pointing to different directions can be generated through the beam splitter, and the line number of the laser radar can be increased to a large extent.

Description

Technical Field

[0001] This utility model belongs to the field of lidar technology, specifically relating to an optical system for lidar to achieve laser beam splitting. Background Technology

[0002] Three-dimensional imaging lidar, due to its high resolution and strong anti-interference capabilities, is widely used in military remote sensing, disaster prevention and early warning, autonomous driving, and many other fields. To meet the demands of autonomous driving, current three-dimensional lidar systems offer high angular resolution in the horizontal direction, but limitations in device integration in the vertical scanning direction result in lower angular resolution, failing to meet the requirements for panoramic three-dimensional imaging of road surfaces. Currently, two main approaches are used to address the problem of high-precision three-dimensional imaging of road surfaces: one is to introduce vertical scanning devices to achieve two-dimensional scanning of the laser beam, but the imaging speed and accuracy of this method are limited by the scanning devices, increasing system complexity and instability; the other approach is to continuously increase the number of lasers emitting the laser beam to improve the vertical angular resolution, but this method is often costly and difficult to integrate. Therefore, how to improve vertical resolution at a low cost has become a key issue for lidar to achieve applications in various scenarios. Utility Model Content

[0003] (a) Technical problems to be solved

[0004] The technical problem this invention aims to solve is how to provide an optical system for laser beam splitting in lidar, thereby addressing the issue of improving the longitudinal resolution of lidar at a low cost.

[0005] (II) Technical Solution

[0006] To solve the above-mentioned technical problems, this utility model proposes an optical system for laser radar to achieve laser beam splitting, the optical system comprising: a laser source, a collimating lens group and a beam splitter;

[0007] The laser source is used to provide detection pulse signals;

[0008] The collimating lens group is used to collimate the emitted beam;

[0009] The beam splitter is used to separate the collimated beam into multiple laser beams with different directions;

[0010] The incident surface of the beam splitter is a complete plane, while the exit surface is made into a sawtooth refractive surface with different refraction angles through optical micromachining technology.

[0011] (III) Beneficial Effects

[0012] This invention proposes an optical system for laser beam splitting using lidar. The beneficial effects of this invention are as follows:

[0013] 1. This utility model provides an optical system for laser beam splitting in lidar, which requires only one light source or a small number of laser sources. Multiple laser beams pointing in different directions can be generated through a beam splitter, which can maximize the line count of lidar.

[0014] 2. The optical system for laser beam splitting described in this utility model has the characteristics of small size and simple structure, which is beneficial to the miniaturization design of laser radar. Attached Figure Description

[0015] Figure 1 This is a flowchart illustrating the acquisition of beam splitting parameters for the laser radar transmitting optical system according to an embodiment of the present invention.

[0016] Figure 2 This is a schematic diagram illustrating the principle of laser beam splitting achieved by the beam splitter in an embodiment of this utility model.

[0017] Figure 3 This is a three-dimensional view of the beam splitter according to an embodiment of the present invention;

[0018] Figure 4 This is a schematic diagram illustrating the principle of laser refraction in a beam splitter.

[0019] Figure 5 This is a schematic diagram of the optical system principle for laser beam splitting in a lidar according to an embodiment of the present invention. Detailed Implementation

[0020] To make the objectives, contents, and advantages of this utility model clearer, the specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples.

[0021] To address the shortcomings of existing technologies, this invention provides an optical system for laser beam splitting in lidar, which can effectively reduce the complexity of the transmitting system and increase the longitudinal resolution of the lidar.

[0022] The present invention achieves the above-mentioned objectives through the following methods.

[0023] An optical system for laser beam splitting in lidar includes: a laser source, a collimating lens group, and a beam splitter.

[0024] The laser source is used to provide detection pulse signals;

[0025] The collimating lens group is used to collimate the emitted beam;

[0026] The beam splitter is used to separate the collimated beam into multiple laser beams with different directions, and can be designed according to different application requirements.

[0027] The beam splitter has an incident surface that is a complete plane, and an exit surface that is made into a sawtooth refractive surface with different refraction angles through optical micromachining technology.

[0028] Furthermore, the laser source includes a semiconductor laser or a fiber laser.

[0029] Furthermore, the collimating lens group includes a biconvex cylindrical lens, a multi-element combination lens, or a multi-element combination cylindrical lens; the biconvex cylindrical lens or the multi-element combination lens is used to collimate the laser source emitted by the fiber laser, and the multi-element combination cylindrical lens is used to collimate the laser source emitted by the semiconductor laser.

[0030] Furthermore, the number of sawtooth refractive surfaces = the longitudinal field of view of the lidar / the longitudinal angular resolution of the lidar.

[0031] Furthermore, the processing method for the sawtooth refractive surface can be different, such as mask etching or CNC machine tool processing, depending on the actual calculated size of a single refractive surface.

[0032] Furthermore, the longitudinal dimension of the beam splitter should be larger than the beam diameter of the collimated laser.

[0033] Furthermore, the serrated refractive surface includes downward serrations and upward serrations, which are symmetrically distributed.

[0034] Furthermore, when the number of longitudinal laser beams cannot be met after splitting a single collimated laser beam, multiple laser sources are stacked longitudinally in front of the collimating mirror.

[0035] Furthermore, referring to the illustrations of this utility model, after the incident collimated light passes through refracting surfaces with different refraction angles, according to the law of refraction, the longitudinal deflection angle of the laser after passing through the incident surface of the beam splitter and the specific sawtooth-shaped exit surface is calculated to be: ( )-(arcsin(nsin( The refractive index of the beam splitter is... The incident surface and the specific serrated exit surface are The angle of refraction of the laser relative to the incident surface is The angle of refraction of the laser relative to the incident surface is The angle of refraction of the laser relative to the specific sawtooth-shaped exit surface is .

[0036] Example 1:

[0037] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0038] Figure 1 The diagram shown is a flowchart illustrating the acquisition of beam splitting parameters of the optical system for laser beam splitting in a lidar system according to an embodiment of this invention. Figure 1 As shown, the method includes:

[0039] Step S101: Determine the longitudinal field of view of the lidar according to the design requirements of the lidar;

[0040] Step S102: Determine the longitudinal angular resolution of the lidar based on the lidar design requirements and longitudinal field of view.

[0041] Step S103: Calculate the longitudinal pointing angle of each emitted laser beam based on the longitudinal angular resolution;

[0042] Step S104: Calculate the required longitudinal deflection angle of the laser based on the laser pointing angle and the law of refraction, and then design the angle of the refraction surface.

[0043] Figure 2 This is a schematic diagram illustrating the principle of laser beam splitting achieved by the beam splitter. Figure 3 This is a three-dimensional view of the beam splitter according to an embodiment of the present invention. Figure 4 This is a diagram illustrating the principle of laser refraction in a beam splitter. After the incident collimated light passes through refracting surfaces at different angles, the longitudinal deflection angle of the laser can be calculated according to the law of refraction, after passing through the incident surface of the beam splitter and the specific sawtooth-shaped exit surface. ( )-(arcsin(nsin( The refractive index of the beam splitter is... The incident surface and the specific serrated exit surface are The angle of refraction of the laser relative to the incident surface is The angle of refraction of the laser relative to the incident surface is The angle of refraction of the laser relative to the specific sawtooth-shaped exit surface is .

[0044] Figure 5The main components of the optical system for laser beam splitting of the lidar are as follows: 301 is a laser, including but not limited to semiconductor lasers and fiber lasers; 302 is a collimating lens group, including but not limited to multiple combined lenses and multiple combined cylindrical lenses; 303 is a beam splitter with an incident surface that is a complete plane and an exit surface that is made into a sawtooth-shaped refractive surface with different refractive angles through optical micromachining technology.

[0045] The beneficial effects of this utility model are:

[0046] 1. This utility model provides an optical system for laser beam splitting in lidar, which requires only one light source or a small number of laser sources. Multiple laser beams pointing in different directions can be generated through a beam splitter, which can maximize the line count of lidar.

[0047] 2. The optical system for laser beam splitting described in this utility model has the characteristics of small size and simple structure, which is beneficial to the miniaturization design of laser radar.

[0048] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. An optical system for a laser radar to implement laser beam splitting, characterized by, The optical system comprises a laser light source, a collimating mirror group and a beam splitter; The laser light source is used to provide a probe pulse signal; The collimating mirror group is used to collimate the emitted light beam; The beam splitter is used to separate the collimated light beam into multiple laser beams with different directions; The incident surface of the beam splitter is a complete plane, and the exit surface is a sawtooth refractive surface with different refractive angles, which is manufactured by an optical micro-machining process.

2. The optical system for implementing laser beam splitting of a lidar according to claim 1, wherein, The laser light source is a semiconductor laser or a fiber laser.

3. The optical system for implementing laser beam splitting of the lidar according to claim 2, wherein, The collimating mirror group is a double-convex cylindrical lens, a multi-piece combined lens or a multi-piece combined cylindrical lens.

4. The optical system for implementing laser beam splitting of the lidar according to claim 3, wherein, The double-convex cylindrical lens or the multi-piece combined lens is used to collimate the laser light source emitted by the fiber laser.

5. The optical system for implementing laser beam splitting of the lidar according to claim 3, wherein, The multi-piece combined cylindrical lens is used to collimate the laser light source emitted by the semiconductor laser.

6. The optical system for implementing laser beam splitting of a lidar according to any one of claims 1 to 5, wherein, The number of sawtooth refractive surfaces = longitudinal field of view of the laser radar / longitudinal angular resolution of the laser radar.

7. The laser radar optical system for implementing laser beam splitting according to claim 6, wherein, According to the actual calculated size of a single sawtooth refractive surface, a mask etching or numerical control machine tool processing method is adopted.

8. The optical system for implementing laser beam splitting of the lidar according to claim 6, wherein, The longitudinal size of the beam splitter should be greater than the beam diameter of the collimated laser.

9. The optical system for implementing laser beam splitting of the lidar according to claim 6, wherein, When a single collimated laser beam cannot meet the requirement of the number of longitudinal laser beams after being split, multiple laser light sources are stacked longitudinally in front of the collimating mirror.

10. The optical system for implementing laser beam splitting of the lidar according to claim 6, wherein, The sawtooth refractive surface includes downward sawteeth and upward sawteeth, which are symmetrically distributed.

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