Electro-Optic Rearview Mirror Polarizing Element
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Solution Overview
Problem
Conventional interior rearview mirrors with covert video displays suffer from image washout during high ambient lighting conditions, such as daylight, making it difficult for the display to be visible and discernible only when actuated.
Innovation Solution
An interior electro-optic rearview mirror assembly with a video display positioned behind a visible light transflecting/polarizing element, which maximizes light transmission and reflectance, allowing the display to be visible through the mirror while minimizing washout during bright conditions, and includes a thermal conducting element to manage heat generated by the display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a covert video display is placed behind the reflective element of an interior rearview mirror, then the display can be viewed through the mirror by the driver, but the display image becomes washed out and difficult to discern during high ambient lighting conditions such as daylight
Solution Approach 1:
A visible light transflecting/polarizing element is introduced as an intermediary between the display and the reflective element. This element selectively transmits polarized light from the display while reflecting ambient light, thereby enhancing display visibility without being washed out by high ambient lighting conditions
Solution Approach 2:
The optical properties of the mirror assembly are changed by incorporating a polarizing element that alters the polarization state of light. By controlling the polarization parameters, the system maximizes transmission of display light while maintaining reflectance of ambient light, preventing image washout
2Illumination intensity
If a video display is positioned behind the reflective element, then the display is visible through the mirror, but heat generated by the display accumulates and may affect performance
Solution Approach 1:
The thermal management function is extracted as a separate component. A thermal conducting element is added to the mirror assembly to conduct heat away from the display, preventing heat accumulation and maintaining display performance
3Illumination intensity
If the display is made highly visible through the mirror, then the driver can easily see the display image, but the display loses its covert nature when not activated
Solution Approach 1:
The optical properties of the mirror assembly are made dynamic through the use of a polarizing element that responds to the display's activation state. When the display is off, the polarizing element maintains the mirror's reflective properties for covert operation. When the display is activated, the polarizing element transmits the polarized display light, making it visible to the driver
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 enhances the visibility of the display image by optimizing light transmission and reflectance, reducing washout during high ambient lighting, and ensures the display remains covert when not activated, while effectively dissipating heat to maintain performance.
Implementation Method 1
maximizes light transmission and reflectance
Implementation Method 2
maximizes light transmission and reflectance
Implementation Method 3
visible light transflecting/polarizing element
Implementation Method 4
thermal conducting element to manage heat generated by the display
Implementation Method 5
effectively dissipating heat to maintain performance
Data Source
AI summary
A vision system for a vehicle includes a forward-viewing camera located behind and viewing through a vehicle windshield, a rearward-viewing camera located at a rear of the vehicle, and a common image processor operable for processing captured image data. A video display screen is located within the interior cabin of the vehicle viewable by a driver of the vehicle. The common image processor utilizes object detection software at least during processing of first image data captured by the forward-viewing camera to detect at least one vehicle present exterior the equipped vehicle. Responsive to the vehicle being shifted into a reverse gear and while the driver is executing a reversing maneuver, video images derived from image data captured by at least the rearward-viewing camera are displayed on the video display screen.