Polymer Encapsulant Composition for Flexible OLEDs
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Solution Overview
Problem
Organic electronic devices, such as OLEDs, are vulnerable to moisture and oxygen, leading to reduced light emitting efficiency and service life, with existing encapsulation methods like glass caps and metal caps facing challenges in flexibility, processing difficulties, and mechanical strength issues.
Innovation Solution
A composition for an encapsulant comprising a first copolymer, a second copolymer, photoinitiators, a reactive silicone-based oligomer, and a silicone acrylate-based compound, which forms a curable encapsulant that effectively blocks oxygen and moisture, improving the sensitivity and flexibility of the encapsulant during UV curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass cap is used for encapsulation, then moisture and oxygen blocking is improved, but manufacturing cost increases and flexibility is reduced
Solution Approach 1:
The patent changes the material parameters from traditional glass to a polymer-based encapsulant containing specific inorganic particles (such as alumina, silica, or boehmite particles with specific size ranges of 0.1-10 μm). This parameter change maintains the moisture and oxygen blocking function while significantly reducing manufacturing complexity and cost, as the polymer encapsulant can be applied using conventional coating processes rather than complex glass processing.
Solution Approach 2:
The patent creates a composite encapsulant material by combining polymer resin (such as epoxy, polyimide, or acrylic resin) with inorganic particles (alumina, silica, boehmite, or their combinations). This composite structure provides both the flexibility and adhesion of polymer materials and the moisture/oxygen barrier properties of inorganic particles, resolving the contradiction between reliability and ease of manufacture.
2Reliability
If metal cap is used for encapsulation, then moisture and oxygen blocking is improved, but thermal expansion mismatch causes processing problems
Solution Approach 1:
The patent changes the encapsulant material from metal to a polymer-inorganic composite, fundamentally altering the thermal expansion parameters. The polymer matrix combined with ceramic particles creates a material with thermal expansion characteristics that match the substrate, eliminating the thermal expansion mismatch problems that occur with metal caps during processing and operation.
3Ease of manufacture
If laminating method is used for encapsulation, then manufacturing is simplified, but moisture and oxygen penetrate through bonding interfaces
Solution Approach 1:
The patent incorporates inorganic particles (alumina, silica, boehmite) with specific pore structures and sizes (0.1-10 μm) into the polymer encapsulant. These inorganic particles create a tortuous path and reduce the effective porosity, preventing moisture and oxygen penetration through the encapsulant layer while maintaining the manufacturing simplicity of a single-layer application process.
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 encapsulant composition enhances the service life of organic electronic devices by effectively blocking external moisture and oxygen, improving sensitivity during UV curing and providing a balance of flexibility and strength, suitable for flexible displays.
Implementation Method 1
one or more photoinitiators
Data Source
AI summary
The present invention relates to a composition for an organic electronic device encapsulant and an encapsulant formed by using the same. A composition for an encapsulant according to an exemplary embodiment of the present invention comprises: 1) a first copolymer comprising the first unit represented by Chemical Formula 1, the second unit represented by Chemical Formula 2, and the third unit represented by Chemical Formula 3; 2) a second copolymer comprising the second unit represented by Chemical Formula 2 and the third unit represented by Chemical Formula 3; 3) one or more photoinitiators; 4) a reactive silicone-based oligomer; and 5) a silicone acrylate-based compound.