Weatherable Thermoplastic Substrate for Optoelectronic Devices
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Solution Overview
Problem
Current optoelectronic devices, such as photovoltaic modules, face challenges in achieving long-term durability and protection against extreme weather conditions, including high temperatures, UV radiation, and moisture, while maintaining mechanical toughness and optical transparency, as existing polymer materials fail to provide sufficient weatherability and hermeticity.
Innovation Solution
A thermoplastic substrate with a highly weatherable outer layer, comprising UV absorbers and a self-protecting polymer like resorcinol polyarylate, is used, along with gas diffusion and planarization coatings, to create a mechanically tough and optically transparent assembly that withstands extreme weathering for over 20 years, with enhanced puncture and cut resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluorocarbon polymer (ETFE) is used for weatherability, then resistance toward outdoor weathering is improved, but mechanical strength and cut resistance deteriorate
Solution Approach 1:
The patent uses a composite structure combining fluorocarbon polymer (ETFE) with glass fibers. The fluorocarbon polymer provides excellent weatherability and chemical resistance, while the glass fibers reinforce the material to improve cut resistance and mechanical strength. This composite approach allows the encapsulant to meet both weatherability requirements and mechanical strength requirements that neither material could achieve alone.
2Reliability
If glass is used for protection, then protection against water vapor and mechanical strength are improved, but weight and flexibility deteriorate
Solution Approach 1:
The patent employs a thin film fluorocarbon polymer encapsulant instead of traditional rigid glass. The fluorocarbon polymer forms a flexible barrier that provides protection against water vapor and environmental degradation while maintaining lightweight properties and flexibility. This allows the optoelectronic device to be protected without the weight and rigidity constraints of glass.
3Strength
If glass fibers are added to improve cut resistance, then resistance toward cut damage is improved, but integrity toward water penetration deteriorates
Solution Approach 1:
The patent creates a composite encapsulant material combining fluorocarbon polymer with glass fibers, where the fluorocarbon polymer matrix maintains hermeticity and prevents water penetration, while the glass fiber reinforcement provides cut resistance. The composite structure ensures that the glass fibers are embedded within the continuous polymer matrix, preserving the water-tight integrity while adding mechanical strength.
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 provides optically transparent, weatherable, and hermetic protection for optoelectronic devices, ensuring durability and performance over 20 years under harsh conditions, with improved mechanical toughness and resistance to UV degradation, while maintaining low cost and thickness.
Implementation Method 1
The polymer can be UV protected by a coating comprising a stable matrix material and UV absorbers
Implementation Method 2
gas diffusion barrier coating(s) that can reduce permeation of moisture and other gases
Data Source
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AI summary
An optoelectronic device assembly can comprise: a coated element and an optoelectronic device on the coated element, wherein the optoelectronic device is selected from a light emitting diode and a photovoltaic cell. The coated element can comprise: transparent thermoplastic substrate and a protective weathering layer. The transparent thermoplastic substrate can comprise a material selected from aromatic polycarbonate and polyester, and combinations comprising at least one of the foregoing materials. The protective weathering layer can have a UV absorbance loss rate at 330 nm of less than or equal to 0.15 A/year as estimated from filtered xenon arc exposure and/or having a rate of erosion of less than or equal to 5 micrometer per year as estimated from filtered xenon arc exposure.