Windshield Coating Layout for LiDAR Transmission and HUD Reflection
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Solution Overview
Problem
Current front windshields designed for heat insulation have a high blocking rate for infrared light, which hinders the normal operation and high-precision measurement of internally mounted LiDAR systems used in autonomous driving, as they fail to meet the requirements for LiDAR signals of wavelengths 905 nm or 1550 nm.
Innovation Solution
A windshield assembly comprising an outer glass, a polymer interlayer, and an inner glass with an enhanced reflection coating on the inner glass surface and a dielectric coating on the information collection region, optimized to improve reflectivity for P-polarized light in the visible spectrum and transmittance for near-infrared light, ensuring compatibility with LiDAR and head-up display functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a front windshield is designed with heat insulation properties, then infrared light blocking rate is improved, but transmittance for LiDAR signals is worsened
Solution Approach 1:
The patent applies different coating properties to different regions of the windshield. The first region (driver view area) has enhanced reflection coating for HUD visibility, while the second region (LiDAR area) has dielectric coating for high LiDAR signal transmittance. This local differentiation resolves the contradiction by allowing heat insulation and LiDAR compatibility in the same windshield without compromising either function.
Solution Approach 2:
The patent uses composite coating structures combining organic and inorganic materials. The dielectric coating includes alternating layers of organic material (refractive index 1.3-1.6) and inorganic material (refractive index 1.7-2.7), creating a composite structure that achieves both heat insulation and high transmittance for LiDAR signals at 905nm and 1550nm wavelengths.
2Illumination intensity
If an enhanced reflection coating is applied to improve HUD reflectivity, then reflectivity for P-polarized light is improved, but transmittance for near-infrared light may be worsened
Solution Approach 1:
The patent divides the windshield into two regions: the first region has enhanced reflection coating optimized for HUD reflectivity, while the second region has dielectric coating optimized for LiDAR transmittance. This spatial separation allows each region to optimize its primary function without compromising the other region's performance.
Solution Approach 2:
The dielectric coating uses precisely controlled layer thicknesses (total thickness 50-200nm) and specific refractive index combinations to create optical interference effects that simultaneously maintain high visible light reflectivity for HUD and high near-infrared transmittance for LiDAR signals at 905nm and 1550nm.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The windshield assembly achieves greater than 80% transmittance for near-infrared light and improved reflectivity for P-polarized light, enabling high-precision LiDAR operation and uniform HUD display images within a maximum horizontal field of view of 120°, thus enhancing detection range and precision while ensuring normal operation of internally mounted LiDAR systems.
Implementation Method 1
The enhanced reflection coating is configured to improve a reflectivity of the non-information collection region for P-polarized light of 380 nm ̃780 nm
Implementation Method 2
A dielectric coating is further provided in the information collection region. The dielectric coating is disposed on a side face of the enhanced reflection coating away from the fourth surface. The dielectric coating and the enhanced reflection coating are configured to improve a transmittance of the information collection region for near-infrared light of 780 nm ̃ 980 nm
Data Source
AI summary
A windshield includes an outer glass, a polymer interlayer, and an inner glass. The inner glass has a third surface and a fourth surface opposite the third surface. The third surface faces the polymer interlayer. The windshield has an information collection region and a non-information collection region. An enhanced reflection coating is provided on the fourth surface. The enhanced reflection coating covers the information collection region and the non-information collection region. The enhanced reflection coating is configured to improve a reflectivity of the non-information collection region for P-polarized light of 380 nm˜ 780 nm. A dielectric coating is further provided in the information collection region. The dielectric coating disposed on a side face of the enhanced reflection coating away from the fourth surface.