UV-Shielded Variable-Transmittance Optical Laminate for Smart Windows
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Solution Overview
Problem
Conventional variable-transmittance optical laminates for smart windows suffer from deterioration of the liquid crystal layer due to ultraviolet rays, leading to reduced lifespan and fixed transmittance issues, which affect the efficiency and safety of light control in vehicles and buildings.
Innovation Solution
A variable-transmittance optical laminate is developed with a first polarization plate including an ultraviolet ray protection substrate and a near-ultraviolet ray protection layer, sequentially laminated to face the light source, directly forming transparent conductive layers on the polarization plates without separate substrates, and incorporating a liquid crystal layer to maintain transparency and prevent ultraviolet-induced deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional variable-transmittance optical laminates are used, then transmittance can be adjusted by applying voltage, but ultraviolet rays penetrate the liquid crystal layer causing deterioration and shortened lifespan
Solution Approach 1:
The patent introduces a polarizing film as an intermediary component between the liquid crystal layer and the external environment. This polarizing film incorporates UV-absorbing substances that intercept and absorb ultraviolet rays before they can reach and deteriorate the liquid crystal layer, while still allowing the liquid crystal to function for transmittance control
Solution Approach 2:
The patent converts the harmful UV radiation into a beneficial effect by using UV-absorbing substances in the polarizing film. The UV rays that would normally cause deterioration are instead absorbed and converted into harmless energy, protecting the liquid crystal layer while maintaining the variable transmittance functionality
2Object-affected harmful factors
If polarizing films with UV-absorbing functions are used, then UV protection is provided, but transmittance control capability is limited due to deterioration after voltage application
Solution Approach 1:
The patent merges the functions of UV protection and transmittance control into a single integrated optical laminate structure. The polarizing film with UV-absorbing substances is combined with the liquid crystal layer and transparent conductive layers, creating a unified system that simultaneously provides UV blocking and voltage-controlled transmittance adjustment
Solution Approach 2:
The patent uses composite materials by incorporating UV-absorbing substances into the polarizing film matrix. This creates a composite structure where the polarizing film contains both the polarizing agents and UV-absorbing compounds, enabling dual functionality of polarization and UV protection without compromising transmittance control
3Adaptability or versatility
If existing optical laminates are used, then liquid crystal phase change provides transmittance adjustment, but near-ultraviolet rays penetrate and cause liquid crystal layer damage
Solution Approach 1:
The polarizing film serves as an intermediary barrier that intercepts near-ultraviolet rays before they reach the liquid crystal layer. The UV-absorbing substances in the polarizing film absorb the harmful radiation, protecting the liquid crystal while allowing the phase change transmittance adjustment to function
Solution Approach 2:
The patent applies preliminary protection by incorporating UV-absorbing substances in the polarizing film that act before the liquid crystal layer is exposed to UV rays. This preliminary UV filtration prevents damage before it occurs, allowing the liquid crystal to maintain its phase change capabilities over extended periods
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 laminate effectively blocks ultraviolet and near-ultraviolet rays, preventing liquid crystal layer deterioration, reducing thickness, and improving transmittance while maintaining light control functionality, thus enhancing the quality and longevity of smart windows.
Implementation Method 1
the first polarization plate includes an ultraviolet ray protection substrate, a polarizer, and a near-ultraviolet ray protection layer... effectively blocks ultraviolet and near-ultraviolet rays, preventing liquid crystal layer deterioration
Implementation Method 2
The variable-transmittance optical laminates operate in a manner that the orientation of liquid crystal molecules changes depending on the application voltage, which results in a change in transmittance
Implementation Method 3
a first transparent conductive layer formed on one surface of the first polarization plate... a second transparent conductive layer formed on one surface of the second polarization plate
Data Source
Figure 1~3A
Figure 3B~3C
AI summary
Proposed is a variable-transmittance optical laminate, the optical laminate including a first polarization plate; a first transparent conductive layer formed on one surface of the first polarization plate; a second polarization plate positioned opposite to the first polarization plate; a second transparent conductive layer formed on one surface of the second polarization plate and positioned opposite to the first transparent conductive layer, and a liquid crystal layer interposed between the first transparent conductive layer and the second conductive layer, in which the first polarization plate is formed by laminating an ultraviolet ray protection substrate, a polarizer, and a near-ultraviolet ray protection layer. A method of manufacturing the optical laminate and a smart window including the optical laminate are also proposed.