Electro-optic Element with Aligned Electrochromic Molecules
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Solution Overview
Problem
Conventional rearview mirror systems face challenges in providing a clear display of polarized light while minimizing the impact of ambient light, particularly in bright conditions, due to the inability to effectively control light polarization and transition between transparent and darkened states.
Innovation Solution
A vehicular rearview assembly incorporating a display, a reflective polarizer, and an electro-optic element with aligned polymeric films containing electrochromic molecules, which can transition between clear and darkened states by selectively absorbing specific polarizations of light, allowing for enhanced contrast and reduced ambient light interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional rearview mirror system is used, then the mirror can function as a basic reflective surface, but it cannot effectively control light polarization or transition between transparent and darkened states to reduce ambient light interference
Solution Approach 1:
The patent employs a composite electro-optic element consisting of multiple layers including first and second electro-optic polymers with different electrochromic molecules (cathodic and anodic), electrolyte, and spacer layers between conductive substrates. This composite structure enables the mirror to transition between clear and darkened states while managing light polarization effectively, resolving the contradiction between adaptability and structural complexity.
Solution Approach 2:
The electro-optic element is divided into distinct functional layers: conductive substrate layers, electro-optic polymer layers containing different electrochromic molecules, electrolyte layers, and spacer layers. This segmentation allows each layer to perform its specific function independently, enabling state transitions while maintaining manageable structural complexity.
2Illumination intensity
If the electro-optic element uses randomly oriented electrochromic molecules, then the manufacturing process is simpler, but the ability to selectively absorb specific polarizations of light is reduced
Solution Approach 1:
The patent utilizes the inherent local quality differences between cathodic and anodic electrochromic molecules, where each type naturally absorbs a specific polarization of light. By positioning these molecules in alternating layers with orthogonal orientations, the system achieves selective polarization absorption without requiring complex alignment processes, resolving the contradiction between illumination control and manufacturing precision.
3Reliability
If a single-layer electro-optic element is used, then the device structure is simpler, but the contrast and ability to reduce washout from ambient light is insufficient
Solution Approach 1:
The patent incorporates redundant functional layers with cathodic and anodic electrochromic molecules that can compensate for each other. If one layer fails or degrades, the other layer maintains the electro-optic functionality, providing beforehand cushioning against failure and ensuring reliable contrast performance throughout the device lifecycle.
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 enables the rearview mirror to function as both a conventional mirror and an electronic display, offering improved contrast and reduced washout from ambient light, with the ability to transition between states without mechanical means, ensuring functionality even in failure scenarios.
Implementation Method 1
A reflective polarizer is positioned adjacent the display. The reflective polarizer is configured to transmit the light of the first polarization and reflect light of a second polarization
Implementation Method 2
The electro-optic element includes a plurality of electrochromics substantially aligned with the second polarization of the light such that the electro-optic element is configured to substantially absorb the light of the second polarization when in the darkened state
Implementation Method 3
the polymeric chains are aligned with the light of the second polarization, the polymeric film being variably transmissive to the light of the second polarization
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
A vehicular rearview assembly is provided that includes a display configured to emit light of a first polarization. A reflective polarizer is positioned adjacent the display. The reflective polarizer is configured to transmit the light of the first polarization and reflect light of a second polarization and an electro-optic element is positioned on an opposite side of the reflective polarizer than the display. The electro-optic element is configured to transition between substantially clear and substantially darkened states. The electro-optic element includes a plurality of electrochromic molecules substantially aligned with the second polarization of the light such that the electro-optic element is configured to substantially absorb the light of the second polarization when in the darkened state.