Multi-Color Optical Transmission Cells for Neutral Tint Switching
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Solution Overview
Problem
Existing variable transmission optical devices face challenges in achieving a wide transmission swing, polarization independence, and multi-colored states, particularly in applications requiring quick adaptability and strict optical requirements, such as military and eyewear, due to limitations in liquid crystal systems and dichroic dyes.
Innovation Solution
A multi-color variable transmission optical device (MC-VTOD) is designed with two electro-optic cells, each containing a different electro-optic material, allowing independent control of light transmittance in distinct wavelength regions, achieving clear, tinted, and colorimetrically neutral states through applied electric fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a guest-host liquid crystal/dye system is used to achieve a large transmission swing, then the transmission difference between clear and tinted states is improved, but the dye disrupts the liquid crystalline phase and increases polarization dependence
Solution Approach 1:
The device is divided into multiple independent electro-optic cells, each responsible for a specific wavelength region. This segmentation allows each cell to use optimized electro-optic materials without the compromising effects of dichroic dyes, maintaining polarization independence while achieving overall transmission swing through coordinated operation of multiple cells.
Solution Approach 2:
The patent uses composite electro-optic material systems in each cell, combining liquid crystal hosts with carefully selected guests or dopants that provide the desired optical effects without the harmful polarization dependence of traditional dichroic dyes. This composite approach enables transmission control while preserving optical quality.
2Ease of manufacture
If high performing dichroic dyes are used to achieve transmission swing, then the clear and tinted state difference is improved, but the device exhibits poor optical performance due to structural imperfections and color distortion
Solution Approach 1:
The patent extracts and removes the problematic dichroic dyes from the system entirely. Instead of using dye-based guest-host systems, the invention employs alternative electro-optic materials that achieve transmission modulation through different mechanisms, eliminating the source of polarization dependence and optical imperfections.
Solution Approach 2:
Each electro-optic cell is designed with locally optimized properties for its specific wavelength region. The electro-optic materials, cell gaps, and operating parameters are tailored to each cell's function, enabling precise control of transmission characteristics without the compromises required by a single universal dye system.
3Device complexity
If a single electro-optic cell is used to provide transmission control, then the device structure is simple, but the device cannot achieve multiple tinted states or colorimetrically neutral states
Solution Approach 1:
The device is segmented into multiple electro-optic cells, each controlling a specific wavelength region. This segmentation enables independent control of different color components, allowing the device to achieve multiple tinted states and colorimetrically neutral states by selectively activating combinations of cells.
Solution Approach 2:
Each electro-optic cell serves multiple functions: it provides transmission control for its wavelength region, contributes to overall transmission swing, and enables color tuning when combined with other cells. This multi-functionality allows a single cell to perform what would otherwise require multiple specialized components.
4Reliability
If polarizer-based liquid crystal systems are used to achieve minimal transmission in dark state, then the dark state transmission is improved, but the overall light transmission is limited to below 50%
Solution Approach 1:
The patent removes polarizers from the optical system entirely. Instead of using polarizer-based liquid crystal systems that inherently limit transmission, the invention employs electro-optic cells that achieve dark state transmission control through alternative mechanisms, eliminating the 50% transmission ceiling imposed by polarizers.
Solution Approach 2:
The device uses composite electro-optic material systems that combine liquid crystal hosts with specialized guests or dopants designed to provide high contrast ratios without requiring polarizers. These composite materials achieve minimal dark state transmission while maintaining high clear state transmission, overcoming the limitations of polarizer-based systems.
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 MC-VTOD provides a wide transmission swing, polarization independence, and multiple tinted states, enhancing adaptability and optical performance by enabling quick transitions between clear and tinted states with reduced color distortion and improved optical clarity.
Implementation Method 1
The first electro-optic material is capable of changing from a state of higher light transmittance to a state of lower light transmittance in a first wavelength region upon a change in a first electric field applied across the first electro-optical material
Implementation Method 2
The second electro-optic material is capable of changing from a state of higher light transmittance to a state of lower light transmittance in a second wavelength region different from the first wavelength region upon a change in a second electric field applied across the second electro-optical material
Data Source
AI summary
A multi-color variable transmission optical device (“MC-VTOD”) includes a first cell having a first electro-optic material provided between a first pair of substrates and a second cell having a second electro-optic material provided between a second pair of substrates.The first electro-optic material can changing from a state of higher light transmittance to a state of lower light transmittance in a first wavelength region upon a change in an electric field applied across the first electro-optical material. The second electro-optic material is capable of changing from a state of higher light transmittance to a state of lower light transmittance in a second wavelength region different from the first wavelength region upon a change in an electric field applied across the second electro-optical material. The MC-VTOD is switchable between i) a clear state wherein the first cell and second cell are in the state of higher light transmission, ii) a first tinted state wherein the first cell is in a state of lower light transmittance and the second cell is in a state of higher light transmittance, and iii) a colorimetrically neutral darkened state wherein at least the second cell is in a state of lower light transmittance. At least the first cell is characterized by a narrow band absorption of 175 nm or less in its state of lower light transmittance.