Display Mirror Assembly Glare Management
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Solution Overview
Problem
Existing rearview mirror systems face challenges in managing glare from trailing vehicle headlights, particularly at night, which can lead to blooming and smear in camera systems and interfere with the driver's view of the rearward scene.
Innovation Solution
A display mirror assembly incorporating an electrochromic cell and a switchable reflective element, controlled by a controller, automatically switches between mirror mode and display mode based on light levels, using an electrochromic cell to attenuate glare and allow for clear viewing of the rearward scene, and a display module to show camera images during the day.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a camera system is used to capture rearward scenes, then daytime visibility is improved, but glare from trailing headlights causes blooming and smear at night
Solution Approach 1:
An electrochromic cell is positioned between the camera and the driver to selectively attenuate glare from trailing headlights while allowing the camera image to pass through. The cell acts as an intermediary that can be dynamically adjusted to block harmful light during nighttime conditions without obstructing the useful camera feed.
Solution Approach 2:
The electrochromic cell changes its optical properties (light transmission) in response to varying light conditions. During nighttime when glare is present, the cell transitions to a state that attenuates light; during daytime, it transitions to a clear state that allows maximum light transmission for optimal camera visibility.
2Object-affected harmful factors
If an electrochromic cell is used to reduce glare, then nighttime mirror mode viewing is improved, but the system complexity increases
Solution Approach 1:
The electrochromic cell serves multiple functions: it acts as a glare reduction filter for the mirror, a protective element for the camera lens, and a controllable light attenuator for the display module. This multi-functionality reduces the need for separate components and simplifies the overall system architecture.
Solution Approach 2:
The patent combines the electrochromic cell with the camera housing and mirror assembly into an integrated unit. The cell is positioned to simultaneously protect the camera and reduce glare on the mirror surface, merging multiple protective and functional elements into a single component structure.
3Adaptability or versatility
If the reflective element is made switchable between high and low reflection states, then adaptability to different lighting conditions is improved, but device complexity increases
Solution Approach 1:
The reflective element is designed to be dynamically switchable between high reflection state (for nighttime mirror mode) and low reflection state (for daytime display mode). This dynamic capability allows the system to adapt to varying lighting conditions, and the controller automatically manages the switching based on ambient light sensor input.
Solution Approach 2:
An ambient light sensor provides feedback to the controller about current lighting conditions. The controller uses this feedback to automatically determine when to switch the reflective element between high and low reflection states, enabling automatic adaptation without requiring manual intervention from the driver.
4Illumination intensity
If a display module is added to show camera images, then daytime rearward visibility is improved, but interference with nighttime mirror viewing occurs
Solution Approach 1:
The display module is dynamically controlled to be visible only when needed - during daytime when camera images are required. During nighttime, the display module is deactivated or its brightness is reduced to prevent interference with the mirror view, allowing the system to provide optimal viewing experience for different time periods.
Solution Approach 2:
The electrochromic cell provides localized glare reduction specifically for the mirror viewing area during nighttime, while the display module operates in the camera display area during daytime. This spatial and temporal separation of functions allows both modes to operate effectively without mutual 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 glare from trailing headlights, providing a superior view of the rearward scene by automatically adjusting between mirror and display modes, minimizing interference from camera images at night and ensuring clear visibility during the day.
Implementation Method 1
The mirror incorporates an electrochromic cell positioned between the camera and the driver
Implementation Method 2
The reflective element is switchable between a first state in which the reflective element has a high reflection and a second state in which the reflective element has a low reflection
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A display mirror assembly for a vehicle includes an electrochromic cell, a switchable reflective element, a display module, an ambient light sensor, and a controller. The controller automatically selects a display mode or a mirror mode in response to a detected ambient light level. In a display mode, the controller activates the display module, sets the switchable reflective element to a low reflection mode, and sets the electrochromic cell to a clear state with minimum attenuation. In a mirror mode, the controller deactivates the display module, sets the switchable reflective element to a high reflection mode, and varies attenuation by the electrochromic cell.