LiDAR Refraction Compensation via Polarization and Curved Covers
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Solution Overview
Problem
LiDAR systems face challenges in maximizing refraction and minimizing reflection when light passes through mediums with different refractive indices, leading to ghost image formation and reduced accuracy due to Fresnel effects, especially when incident angles exceed a few degrees.
Innovation Solution
The implementation of a LiDAR system with a laser emitting both p-polarization and s-polarization light, aligned with a light transmissive cover having a reflective polarization plane, and the use of curved or AR-coated windshield covers to adjust beam fields of view, minimizing deformation and ghost image formation by compensating for Fresnel properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If light passes through a windshield or cover at incident angles exceeding a few degrees, then the LiDAR system can achieve a wider field of view, but Fresnel effects cause increased reflection and ghost image formation
Solution Approach 1:
The patent applies anti-reflective coatings that utilize optical interference principles to convert the harmful Fresnel reflection effects into beneficial light transmission. The multi-layer coating structure is designed to create destructive interference for reflected light waves while allowing transmitted light to pass through, effectively transforming the reflection problem into a transmission solution across wide incident angle ranges.
Solution Approach 2:
The patent employs curved windshield covers with specific radius of curvature parameters to modify the incident angle distribution of light beams. By changing the geometric parameter (curvature radius) of the windshield cover, the system optimizes light transmission characteristics and reduces ghost image formation while maintaining a wide field of view.
2Reliability
If a light transmissive cover is used to protect the LiDAR system, then environmental protection is improved, but reflection and light transmission loss increase due to Fresnel effects
Solution Approach 1:
The patent uses composite anti-reflective coating structures consisting of multiple layers with different refractive indices. This composite material approach creates optimal optical interference conditions that minimize reflection losses while maintaining the protective function of the windshield cover, allowing light to transmit efficiently through the protective barrier.
3Use of energy by moving object
If anti-reflective coatings are applied to the windshield, then light transmission is improved, but the complexity of the windshield manufacturing process increases
Solution Approach 1:
The patent integrates the anti-reflective function directly into the curved geometry of the windshield cover itself, rather than requiring separate flat coatings. The curvature is designed to work synergistically with the anti-reflective properties, combining protective coverage with light transmission optimization in a single manufactured component, thereby reducing overall manufacturing complexity.
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
This approach maximizes light transmission and minimizes reflection across a wide range of incidence angles, reducing ghost images and enhancing the accuracy and reliability of LiDAR systems in various vehicle environments.
Implementation Method 1
a laser operative to emit light characterized as having a p-polarization and s-polarization; and a light transmissive cover characterized as having a reflective polarization plane, wherein the laser is aligned with the light transmissive cover such that the p-polarization of the laser is co-planer with the reflective polarization plane of the light transmissive cover
Implementation Method 2
a curved cover for use with LiDAR system can be provided that can include a medium comprising a first curve and a second curve, wherein the first and second curves are designed to minimize deformation of exiting and receiving light beams and to prevent formation of ghost images
Implementation Method 3
a windshield cover mounted to the windshield, wherein the windshield cover is operative to adjust the beam field of view to yield an exit beam field of view that compensates for Fresnel properties of the windshield
Data Source
AI summary
Embodiments discussed herein refer to LiDAR systems that use refraction compensation to improve transmission efficiency of light energy through transmissive mediums such as covers. Refraction compensation can be achieved using a cover or an anti-reflective coating.