Vehicle Polarization Filter for Precipitation Glare Reduction
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Solution Overview
Problem
Conventional vehicle headlights illuminate precipitation, causing distracting flickering streaks for drivers and vehicle sensors, while active or 'smart' headlights are expensive and prone to failure in harsh environments.
Innovation Solution
A 'passive' headlight system using light polarization, with a first polarizer in front of the headlight and a second polarizer in front of the sensor, to minimize precipitation illumination by blocking refracted-reflected light while allowing reflected light to pass through, thereby enhancing visibility and reducing interference with sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional headlights are used to illuminate the road, then driver visibility is improved, but precipitation appears as distracting flickering streaks
Solution Approach 1:
The patent changes the polarization parameter of the light by introducing a first polarizer in front of the headlight and a second polarizer in front of the sensor with perpendicular orientations. This parameter change allows the system to differentiate between reflected light from the road and refracted-reflected light from precipitation, eliminating the distracting flickering streaks while maintaining road illumination.
2Object-affected harmful factors
If active or smart headlights are used to reduce precipitation illumination, then precipitation visibility is improved, but system cost and reliability deteriorate
Solution Approach 1:
The patent replaces the complex mechanical active headlight system (comprised of projector, camera, and beamsplitter) with a simpler optical system using polarizers. This substitution eliminates the need for moving parts and complex image processing mechanisms, thereby improving reliability while reducing cost, yet still achieves the goal of minimizing precipitation illumination through polarization filtering.
3Object-affected harmful factors
If active or smart headlights are used to reduce precipitation illumination, then precipitation visibility is improved, but system cost increases
Solution Approach 1:
The patent employs inexpensive polarizer films or sheets instead of expensive active headlight components. These polarizers can be easily manufactured and installed, making the system cost-effective while achieving the same functional result of reducing precipitation illumination that would otherwise require costly projector-camera-beamsplitter assemblies.
4Object-affected harmful factors
If polarizers are added to the headlight and sensor system, then precipitation interference is reduced, but device complexity increases
Solution Approach 1:
The patent segments the optical system into distinct functional components: a first polarizer attached to the headlight, a second polarizer attached to the sensor, and the precipitation interface. This segmentation allows each component to perform its specific function independently, making the overall system easier to manufacture, install, and maintain despite the added functionality of reducing precipitation interference.
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 system effectively reduces precipitation illumination, improving driver and sensor visibility by differentiating between reflected and refracted light, thus enhancing object detection and image quality without the high costs and reliability issues of active systems.
Implementation Method 1
A first polarizer is disposed in front of at least one headlight disposed at the vehicle, and light emitted by the at least one headlight passes through the first polarizer to emit polarized light
Implementation Method 2
A second polarizer is disposed in front of the sensor, and light received by the sensor first passes through the second polarizer, and the second polarizer has an opposite-handed configuration relative to the first polarizer. The polarized light reflects and refracts off of precipitation and the second polarizer blocks refracted-reflected light from the precipitation and allows reflected light from the precipitation to pass through to the sensor
Implementation Method 3
The polarized light reflects and refracts off of precipitation
Implementation Method 4
The polarized light reflects and refracts off of precipitation
Data Source
AI summary
A sensing system for a vehicle includes a sensor disposed at a vehicle and a control that includes a processor for processing sensor data captured by the sensor. A first polarizer is disposed in a light emitting path of at least one light source of the vehicle and a second polarizer is disposed in a light receiving path of the sensor. The second polarizer has an opposite-handed polarization configuration relative to the first polarizer. Some of the polarized light as polarized by the first polarizer impinges precipitation present in the field of sensing of the sensor and returns toward the sensor as refracted-reflected light. The second polarizer attenuates the refracted-reflected light and allows light reflected from objects present in the sensor's field of sensing to pass through to the sensor. The control, responsive to processing of captured sensor data, detects objects in the field of sensing of the sensor.