Photopolymerizable Adhesive Composition for Flexible Electronics Encapsulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is a need for an adhesive composition that effectively encapsulates flexible electronic and optoelectronic devices, providing satisfactory properties such as adhesive, optical, thermal, electrical, gas-barrier, elastic, and strength properties, while minimizing lateral permeation of gases and water and preventing photo-ageing.
Innovation Solution
A photopolymerizable adhesive composition comprising 20-35% block copolymer, 45-75% (meth)acrylate monomer with a glass transition temperature of at least 85°C, 2-15% alkoxysilane (meth)acrylate monomer, and 0.1-5% photoinitiator, which is applied and photopolymerized to form a polymerized adhesive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a photopolymerizable adhesive composition is used to encapsulate flexible electronic devices, then adhesive strength and barrier properties are improved, but lateral permeation of gases and water may occur at the free edges of the adhesive
Solution Approach 1:
The patent modifies the chemical composition parameters of the adhesive by incorporating specific silane compounds (2-15% by weight) and controlling the glass transition temperature (85-120°C) through monomer selection. These parameter changes enhance the adhesive's ability to resist lateral permeation while maintaining flexibility and adhesion to barrier layers.
Solution Approach 2:
The patent creates a composite adhesive system combining multiple components: (meth)acrylate monomers, block copolymers, silane (meth)acrylate, and photoinitiators. This composite formulation synergistically provides both barrier properties against lateral permeation and the flexibility required for flexible electronic devices.
2Adaptability or versatility
If the adhesive composition is made more flexible to accommodate flexible devices, then adaptability to device flexing is improved, but resistance to operational stresses and durability may be reduced
Solution Approach 1:
The patent precisely controls the glass transition temperature parameter within the 85-120°C range by selecting specific (meth)acrylate monomers. This parameter optimization allows the adhesive to remain flexible at operating temperatures while developing sufficient strength and stress resistance when cured.
Solution Approach 2:
The patent creates different mechanical properties at different stages: the uncured adhesive maintains flexibility for application and device accommodation, while the photopolymerized cured adhesive provides strength and stress resistance. This local quality differentiation in time (before and after curing) resolves the contradiction between flexibility and strength.
3Object-affected harmful factors
If the adhesive layer thickness is increased to reduce lateral permeation, then barrier effectiveness is improved, but the device becomes more rigid and less flexible
Solution Approach 1:
Instead of increasing thickness, the patent changes the chemical composition parameters of the adhesive to achieve better barrier performance. The inclusion of silane (meth)acrylate (2-15%) and optimization of monomer glass transition temperature enable effective lateral permeation resistance at standard thicknesses while preserving device flexibility.
Solution Approach 2:
The patent uses barrier layers (such as metal oxide layers or multilayer polymer structures) as the primary barrier against lateral permeation, copying the protective function from traditional rigid encapsulation to flexible devices. The adhesive's role is modified to primarily provide adhesion and sealing rather than being the main barrier, thus maintaining flexibility.
4Ease of manufacture
If conventional adhesive compositions are used, then ease of manufacture is maintained, but photo-ageing (yellowing) and time-limited durability occur
Solution Approach 1:
The patent modifies the chemical composition by selecting specific photoinitiators and (meth)acrylate monomers with high resistance to photo-oxidation and yellowing. The glass transition temperature parameter (85-120°C) is optimized to ensure the cured adhesive maintains its optical and mechanical properties over time under operational conditions including light exposure.
Solution Approach 2:
The patent employs a photopolymerizable composition that cures rapidly upon UV exposure, creating a stable, crosslinked network that resists further degradation. This approach replaces long-lived uncured adhesive with a short-curing-time formulation that achieves durable, photo-resistant properties immediately after curing, eliminating ongoing photo-ageing issues.
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 adhesive composition exhibits excellent adhesive, optical, thermal, electrical, barrier, elastic, and strength properties, effectively encapsulating flexible electronic and optoelectronic devices while preventing lateral permeation and photo-ageing.
Implementation Method 1
a photopolymerizable adhesive composition comprising 20-35% block copolymer, 45-75% (meth)acrylate monomer with a glass transition temperature of at least 85°C, 2-15% alkoxysilane (meth)acrylate monomer, and 0.1-5% photoinitiator, which is applied and photopolymerized to form a polymerized adhesive
Data Source
AI summary
The present invention relates to photopolymerizable adhesive compositions used in the encapsulation of electronic and optoelectronic devices, in particular flexible electronic and optoelectronic devices, for example photovoltaic cells, in order to protect them against gas and moisture permeation.