Vehicle-mounted laser radar window depolarization antireflection film
Patent Information
- Application Number
- CN202522414665.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-14
- Publication Date
- 2026-10-16
- Estimated Expiration
- 2035-11-14
AI Technical Summary
[0003]在激光雷达入射角度(AOI)在0～60°逐渐变大时，S-偏振光与P-偏振光差异逐渐变大，如果雷达在移动(比如装在行驶的汽车上)，其自身姿态(俯仰、旋转)会不断变化，这导致激光束相对于激光雷达视窗的入射角度和偏振方向也在实时变化，使得激光束在P和S偏振状态之间动态变化，导致透射过视窗的能量忽大忽小，使发射到外界的光功率不稳定，影响在不同姿态下的探测一致性；同时，入射时被视窗内表面反射回来的那部分S偏振光，并不会消失，它会直接在雷达内部形成一个虚假的回波信号，严重干扰激光雷达对真实环境的感知
[0009]与现有技术相比，本实用新型结构简单，能够在AOI＝0～60°入射角范围内实现良好的消除偏效果(减小P-偏振光和-偏振光差值)，同时也能实现增透减反效果，解决了激光雷达视窗0-60°入射光线偏振现象对激光雷达的干扰，提高了激光雷达系统光学信号稳定性及对真实环境的感知能力。
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Figure CN224861766U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of antireflective coating technology, specifically to an antipolarization antireflective coating for a vehicle-mounted lidar window. Background Technology
[0002] LiDAR determines distance by measuring the time and phase differences of laser signals and uses Doppler imaging technology to create a clear 3D image of the target. LiDAR emits and receives laser beams, analyzes the time it takes for the laser to return after encountering the target object, calculates the relative distance to the target, and uses the 3D coordinates, reflectivity, and texture information of a large number of dense points on the target object's surface collected during this process to derive a 3D model and related data of the target, creating a 3D point cloud map and drawing an environmental map to achieve environmental perception. The LiDAR window, as a crucial component, serves both to protect the internal structure and to emit and receive laser beams. According to the Fresnel reflection principle, near a certain angle (Brewster's angle), the reflectivity of P-polarized light becomes very low, almost entirely transmitted; while S-polarized light always has a high reflectivity.
[0003] As the incident angle (AOI) of the lidar gradually increases from 0 to 60°, the difference between S-polarized and P-polarized light gradually increases. If the lidar is moving (e.g., mounted on a moving car), its own attitude (pitch, rotation) will constantly change. This causes the incident angle and polarization direction of the laser beam relative to the lidar window to change in real time, resulting in dynamic changes between P and S polarization states. This causes the energy transmitted through the window to fluctuate, making the light power emitted to the outside unstable and affecting the consistency of detection under different attitudes. At the same time, the part of S-polarized light reflected back by the inner surface of the window does not disappear. It directly forms a false echo signal inside the lidar, seriously interfering with the lidar's perception of the real environment. Utility Model Content
[0004] The purpose of this invention is to provide an anti-polarization antireflection film for vehicle-mounted lidar windows that can achieve good anti-polarization effect within the incident angle (AOI) range of 0 to 60°.
[0005] This utility model provides the following technical solution:
[0006] This utility model proposes an anti-polarization antireflection film for a vehicle-mounted lidar window, comprising a first SiO2 film layer for depositing on the vehicle-mounted lidar window, wherein a first TiO2 film layer, a second SiO2 film layer, an Al2O3 film layer, a second TiO2 film layer, a third SiO2 film layer, and an anti-fouling AS film layer are sequentially deposited on the first SiO2 film layer.
[0007] Furthermore, the thickness of the first SiO2 film is 228.64±0.1nm, the thickness of the first TiO2 film is 30.41±0.1nm, the thickness of the second SiO2 film is 59.76±0.1nm, the thickness of the Al2O3 film is 213.82±0.1nm, the thickness of the second TiO2 film is 92.71±0.1nm, the thickness of the third SiO2 film is 324.85±0.1nm, and the thickness of the antifouling AS film is 10.00±0.1nm.
[0008] Furthermore, at a test wavelength of 550nm and a light incident angle of 0-60°, the refractive indices of the first, second, and third SiO2 films are all 1.43-1.47; the refractive indices of the first and second TiO2 films are both 2.35-2.45; the refractive index of the Al2O3 film is 1.65-1.69; and the refractive index of the antifouling AS film is 1.48-1.5.
[0009] Compared with the prior art, this utility model has a simple structure and can achieve good anti-polarization effect (reducing the difference between P-polarized light and -polarized light) within the incident angle range of AOI = 0 to 60°. At the same time, it can also achieve anti-reflection and anti-reflection effects, solve the interference of the polarization phenomenon of incident light in the 0-60° incident light window of the lidar to the lidar, and improve the optical signal stability of the lidar system and its ability to perceive the real environment. Attached Figure Description
[0010] Figure 1 This is a diagram showing the arrangement of the membrane layers of this utility model.
[0011] Figure 2 The reflectivity of this invention is measured at an incident angle of 0°.
[0012] Figure 3 The transmittance of this invention is measured at an incident angle of 0°.
[0013] Figure 4 The reflectivity of P-rays and S-rays of this invention is given at an incident angle of 30°.
[0014] Figure 5 The reflectivity of P-rays and S-rays of this invention is given at an incident angle of 60°.
[0015] 00 - Vehicle-mounted LiDAR window; 1 - First SiO2 film layer; 2 - First TiO2 film layer; 3 - Second SiO2 film layer; 4 - Al2O3 film layer; 5 - Second TiO2 film layer; 6 - Third SiO2 film layer; 7 - Anti-fouling AS film layer. Detailed Implementation
[0016] The following is in conjunction with the appendix Figure 1 The present invention will be further described below.
[0017] like Figure 1 As shown, in one embodiment of this utility model, an anti-polarization antireflection film for a vehicle-mounted lidar window includes a first SiO2 film layer 1 for depositing on the vehicle-mounted lidar window 00. The first SiO2 film layer 1 is sequentially coated with a first TiO2 film layer 2, a second SiO2 film layer 3, an Al2O3 film layer 4, a second TiO2 film layer 5, a third SiO2 film layer 6, and an anti-fouling AS film layer 7. This solves the interference of the 0-60° incident light polarization phenomenon on the lidar window, thereby improving the lidar's perception performance of the real environment.
[0018] In the above embodiments, the material of the vehicle-mounted LiDAR window is PC.
[0019] In one embodiment of this utility model, the thickness of the first SiO2 film layer 1 is 228.64±0.1nm, the thickness of the first TiO2 film layer 2 is 30.41±0.1nm, the thickness of the second SiO2 film layer 3 is 59.76±0.1nm, the thickness of the Al2O3 film layer 4 is 213.82±0.1nm, the thickness of the second TiO2 film layer 5 is 92.71±0.1nm, the thickness of the third SiO2 film layer 6 is 324.85±0.1nm, and the thickness of the antifouling AS film layer 7 is 10.00±0.1nm.
[0020] In one embodiment of this utility model, at a test wavelength of 550nm and a light incident angle of 0-60°, the refractive indices of the first SiO2 film layer 1, the second SiO2 film layer 3, and the third SiO2 film layer 6 are all 1.43-1.47; the refractive indices of the first TiO2 film layer 2 and the second TiO2 film layer 5 are both 2.35-2.45; the refractive index of the Al2O3 film layer 4 is 1.65-1.69; and the refractive index of the antifouling AS film layer 7 is 1.48-1.5.
[0021] In practical applications, the vehicle-mounted LiDAR window is cleaned using an ultrasonic cleaner, then baked at 80±5℃ for 1 hour. Afterward, the window is placed in a vacuum electron beam evaporation coating machine (vacuum degree 2×10⁻⁶ during film deposition). -3(Pa, vacuum chamber ambient heating temperature 80℃), on the surface of the vehicle-mounted lidar window, a first SiO2 film layer (thickness 228.64±0.1nm, deposition rate 10 Å / s), a first TiO2 film layer (thickness 30.41±0.1nm, deposition rate 3.5 Å / s), a second SiO2 film layer (thickness 59.76±0.1nm, deposition rate 10 Å / s), an Al2O3 film layer (thickness 213.82±0.1nm, deposition rate 3 Å / s), a second TiO2 film layer (thickness 92.71±0.1nm, deposition rate 3.5 Å / s), a third SiO2 film layer (thickness 324.85±0.1nm, deposition rate 10 Å / s), and an anti-fouling AS film layer (thickness 10.00±0.1nm, deposition rate 8 Å / s) are sequentially deposited;
[0022] The anti-polarization antireflection film of this utility model for the vehicle-mounted lidar window can achieve ultra-low reflection when the incident light angle AOI = 0°, such as... Figure 2 As shown, the average reflectivity of the vehicle-mounted lidar in the 1520-1580nm operating band is less than 0.02%, such as... Figure 3 As shown, the average transmittance of the vehicle-mounted lidar in the 1520-1580nm operating band is higher than 99%, which has a good anti-reflection and anti-reflection effect and can improve the optical performance of the lidar.
[0023] It can also eliminate the polarization phenomenon of light when incident at large angles, avoiding interference from the polarization problem of light incident at large angles with the lidar's perception of the real environment. For example... Figure 4 As shown, when the incident angle AOI = 30°, the average reflectivity of S-ray is 0.046%, and the average reflectivity of P-ray is 0.127%, with a difference of <0.1% between P-ray and S-ray. Figure 5 As shown, when the incident angle AOI = 60°, the average reflectivity of S-ray is 3.0%, the average reflectivity of P-ray is 3.0%, and the difference between P-ray and S-ray is <0.1%.
[0024] Light rays with different incident angles can achieve a difference of less than 0.1% between P-rays and S-rays when passing through the lidar window. The anti-polarization antireflection film of the vehicle lidar window proposed in this invention not only has a good antireflection and antireflection effect, but also achieves an excellent anti-polarization effect, which can greatly improve the lidar's perception of the real environment and improve driving safety.
[0025] The embodiments of this utility model are given for the purpose of illustration and description. Although embodiments of this utility model have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this utility model. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this utility model.
Claims
1. A polarization-depolarizing antireflective coating for a vehicle-mounted lidar window, characterized in that: It includes a first SiO2 film layer for coating on the vehicle-mounted lidar window, on which a first TiO2 film layer, a second SiO2 film layer, an Al2O3 film layer, a second TiO2 film layer, a third SiO2 film layer, and an anti-fouling AS film layer are sequentially coated.
2. The anti-polarization antireflective coating for a vehicle-mounted lidar window according to claim 1, characterized in that: The thickness of the first SiO2 film is 228.64±0.1nm, the thickness of the first TiO2 film is 30.41±0.1nm, the thickness of the second SiO2 film is 59.76±0.1nm, the thickness of the Al3O3 film is 213.82±0.1nm, the thickness of the second TiO2 film is 92.71±0.1nm, the thickness of the third SiO2 film is 324.85±0.1nm, and the thickness of the antifouling AS film is 10.00±0.1nm.
3. The anti-polarization antireflection film for a vehicle-mounted lidar window according to claim 1, characterized in that: At a test wavelength of 550nm and an incident light angle of 0-60°, the refractive indices of the first, second, and third SiO2 films are all 1.43-1.47; the refractive indices of the first and second TiO2 films are both 2.35-2.45; the refractive index of the Al2O3 film is 1.65-1.69; and the refractive index of the antifouling AS film is 1.48-1.5.