Hybrid Variable Transmission Optical Device with Guest-Host Mixture
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Solution Overview
Problem
Existing variable transmissive optical devices face challenges such as slow response times, limited functionality in bright light without UV, and the need for continuous power supply.
Innovation Solution
A hybrid variable transmission optical device featuring a guest-host mixture with a chiral liquid crystal host and a dyestuff material exhibiting both photochromic and dichroic properties, allowing for switching between multiple optical transmission states with and without UV exposure and voltage application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If photochromic dye is used for variable transmission, then the device can change from clear to dark when exposed to UV light, but the response time is slow (5 to 15 minutes recovery time)
Solution Approach 1:
The patent combines photochromic dye molecules with liquid crystal molecules into a single guest-host mixture system. The liquid crystal component provides fast electro-optical response (milliseconds) while the photochromic dye provides UV-responsive color change. This merging allows the device to achieve both adaptability to different light conditions and fast response time by utilizing the complementary strengths of both materials.
Solution Approach 2:
The invention uses a composite material system consisting of photochromic dye embedded in a liquid crystal host matrix. This composite structure allows the photochromic molecules to retain their UV-responsive properties while the liquid crystal environment provides fast switching capability through electro-optical effects, resolving the contradiction between adaptability and response speed.
2Adaptability or versatility
If photochromic dye is used, then the lens can darken in UV light, but it does not function in bright light without UV component (indoor lighting, behind UV-absorbing windows)
Solution Approach 1:
The liquid crystal component adds a second mechanism for transmission control that works independently of UV radiation. The liquid crystal can be switched by applied voltage to control light transmission regardless of UV presence. This makes the device universal, capable of functioning in both UV-containing outdoor light and UV-filtered indoor lighting conditions, eliminating the limitation of UV dependency.
3Speed
If electronically switchable guest-host mixture is used, then fast switching is achieved, but transmission swing is reduced compared to photochromic systems
Solution Approach 1:
By merging photochromic dye and liquid crystal in a guest-host mixture, the system achieves both fast switching (from liquid crystal) and large transmission swing (from photochromic dye). The photochromic component provides substantial absorption change when activated, while the liquid crystal component enables rapid response and additional transmission control, together achieving both fast switching and large transmission swing simultaneously.
4Speed
If electronically switchable system is used, then fast response is achieved, but continuous power supply is required
Solution Approach 1:
The photochromic component provides passive, periodic response to UV radiation without requiring continuous power. The dye molecules automatically darken when exposed to UV and revert when UV is removed. This passive periodic action complements the active electronic switching, allowing the device to achieve fast response without continuous power consumption for the photochromic portion.
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 device achieves rapid switching between clear and dark states, operates effectively in various light conditions, and does not require continuous power for UV activation, enhancing its functionality and efficiency.
Implementation Method 1
a first dyestuff material including one or more dyes, the first dyestuff material having both photochromic and dichroic properties
Implementation Method 2
a first dyestuff material including one or more dyes, the first dyestuff material having both photochromic and dichroic properties
Implementation Method 3
a first chiral liquid crystal (CLC) host having d/p ratio of greater than 0
Data Source
AI summary
A variable transmission optical device includes a cell having d/p ratio of greater than 0.01. The cell includes a pair of substrates each having an electrically conductive layer and a guest-host mixture having both photochromic and dichroic properties provided between the substrates. The cell may be switched between at least three states including: a first state having a first optical transmission when the optical device is not exposed to UV radiation and no voltage is applied to the cell; a second state having a second optical transmission different from the first optical transmission when the optical device is exposed to UV radiation and no voltage is applied to the cell; and a third state having a third optical transmission different from the first or second optical transmission when the optical device is exposed to UV radiation and a voltage is applied to the cell.