Photocurable Barrier Layer for OLED Encapsulation
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Solution Overview
Problem
Organic light emitting diodes (OLEDs) face performance deterioration and lifespan reduction due to moisture and oxygen exposure, with existing sealing methods failing to provide adequate water vapor permeability and outgassing control, leading to issues with curing shrinkage stress and adhesion to inorganic barrier layers.
Innovation Solution
A photocurable composition comprising a photocurable monomer with phosphorus and an amide group, which forms an organic barrier layer with low water vapor permeability, outgassing, and high adhesion to inorganic barrier layers, enhancing the encapsulation of OLEDs by preventing performance deterioration and extending their lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional sealing materials (silicon compounds or polymer resins) are used to form protective films, then ease of manufacture is improved, but water vapor permeability control and outgassing prevention are insufficient
Solution Approach 1:
The patent uses a composite sealing structure combining inorganic barrier layers (silicon oxide, silicon nitride) with organic photocurable resin layers. This composite approach achieves low water vapor permeability (below 10^-10 g·cm/m²·s·Pa) by leveraging the complementary properties of inorganic materials (excellent barrier performance) and organic materials (flexibility and adhesion), resolving the contradiction between ease of manufacture and water vapor permeability control.
Solution Approach 2:
The patent modifies the chemical composition parameters of the sealing materials by incorporating specific inorganic compounds (silicon oxide, silicon nitride) and functional organic compounds (carboxylic acid groups) into the resin system. This parameter change enables the sealing film to achieve both low water vapor permeability and reduced outgassing while maintaining ease of application through photocuring.
2Ease of operation
If photocurable sealing agents are applied to substrates, then ease of operation is improved, but adhesion to inorganic barrier layers remains insufficient
Solution Approach 1:
The patent modifies the chemical composition of the photocurable resin by incorporating carboxylic acid functional groups that can form strong chemical bonds with inorganic barrier layers. This parameter change in chemical composition enables the resin to achieve strong adhesion (above 1000 gf/mm²) to inorganic surfaces while maintaining ease of application through UV photocuring.
Solution Approach 2:
The patent uses the photocurable resin containing carboxylic acid groups as an intermediary layer between the inorganic barrier layer and the external environment. This intermediary resin layer provides both strong adhesion to the inorganic surface and flexibility for sealing, resolving the contradiction between ease of operation and adhesion strength.
3Productivity
If fast photocuring is achieved to reduce curing time, then productivity is improved, but curing shrinkage stress increases causing performance deterioration
Solution Approach 1:
The patent modifies the molecular structure parameters of the photocurable resin by selecting monomers with specific functional groups (carboxylic acid, hydroxyl) and controlling the polymerization reaction to achieve a balance between curing speed and shrinkage. This parameter optimization enables fast photocuring (within seconds to minutes) while minimizing curing shrinkage stress that could cause performance deterioration.
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 composition achieves a photocurable organic barrier layer with extremely low water vapor permeability and outgassing, high adhesion to inorganic layers, and rapid curing, thereby preventing performance degradation and extending the lifespan of OLEDs while minimizing curing shrinkage stress.
Implementation Method 1
photocurable composition which can realize an organic barrier layer having low water vapor permeability and low outgassing after curing
Data Source
AI summary
The present invention relates to: a photocurable composition containing (A) a photocurable monomer and (B) a monomer containing phosphorus and an amide group; and a device including a barrier layer formed of the composition.