Variable Transmission Screen for Adaptive Daylight Glare Control
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Solution Overview
Problem
Existing solutions for mitigating daytime glare during vehicle driving, such as sunglasses and complex electrochromic screens, fail to provide adaptive and efficient attenuation of varying exterior luminosity, often reducing the visual field or having slow response times.
Innovation Solution
A method and device featuring a screen with variable transmission, controlled by a sensor measuring road scene luminosity, using remote control waves to modulate the transmission coefficient in a PWM pulse width modulation cycle, ensuring rapid and adaptive adjustment of light attenuation without hindering the driver's vision or field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If photochromic lenses are used to attenuate sunlight, then driver protection against glare is improved, but the lenses have slow response time to return to clear state and only react to ultraviolet rays which are blocked by windshields
Solution Approach 1:
The patent replaces passive photochromic material with active liquid crystal technology that can be electronically controlled. The liquid crystal cells are arranged in a matrix and can be switched between transparent and opaque states by applying voltage, providing rapid response time and precise control over light transmission.
Solution Approach 2:
The invention implements dynamic control of lens transparency through electronic switching of liquid crystal cells. The system can rapidly adjust between different transmission states based on real-time detection of sunlight position and intensity, unlike static photochromic lenses that slowly adapt to changing conditions.
2Object-affected harmful factors
If a matrix of liquid crystal cells is used to block sunlight, then glare protection is improved, but a large part of the lens surface must be darkened which reduces the visual field
Solution Approach 1:
The patent applies local quality by selectively darkening only specific regions of the lens matrix where sunlight interference occurs. The liquid crystal cells can be individually or regionally controlled to create localized opaque zones that block glare while leaving other areas transparent, thereby preserving the driver's visual field.
Solution Approach 2:
The lens is divided into a matrix of discrete liquid crystal cells that can be independently controlled. This segmentation allows precise control over which portions of the lens are darkened, enabling the system to block glare from specific directions while maintaining visibility in other areas.
3Ease of manufacture
If binary mode control is used for anti-dazzle screens, then manufacturing complexity is reduced, but the glasses are in maximum or minimum transparency only which reduces adaptability
Solution Approach 1:
The invention implements partial action by allowing intermediate states between maximum and minimum transparency. The liquid crystal cells can be switched to various degrees of opacity, providing multiple intermediate transmission levels that adapt to different lighting conditions, rather than being limited to binary on/off states.
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 solution effectively attenuates bright road scenes, preventing driver dazzling while allowing maximum transparency in low luminosity conditions, with automatic and real-time adjustments, ensuring safe and clear visibility without restricting the driver's movements or vision.
Implementation Method 1
The lenses consist of a matrix of liquid crystal cells, the state of transparency of which can be switched rapidly by applying a voltage
Implementation Method 2
a directional photosensitive sensor integrated into the frame of the glasses, for detecting the position and intensity of the sun
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
The invention relates to a method that provides daytime driving assistance for a motor vehicle (20), comprising the following steps consisting in: placing at least one variable transmission screen (26, E, 28) between the driver (24) of the vehicle and the road scene (SR) in front of the vehicle (20); measuring, with at least one sensor (31), the brightness of the road scene (SR) in front of the vehicle; and processing the brightness measurement signal (SL) in order to transform same into a control signal (SC) for controlling the transmission coefficient of the variable transmission screen (26, E, 28). According to the invention, the method comprises the additional step of transmitting the control signal (SC) via remote control waves (OT) to a receiver (40) belonging to the variable transmission screen (26, E, 28) in order to modulate the transmission coefficient (CT) of the variable transmission screen (26, E, 28) as a function of the brightness measured by the sensor (31). The invention is suitable for motor vehicles.