Flexible Encapsulant Composition for OLED Moisture Barrier

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Solution Overview

Problem

Existing encapsulation technologies for organic electronic devices are inadequate in preventing moisture and oxygen ingress, leading to reduced lifespan and flexibility issues, particularly in flexible OLED panels, due to high costs, mechanical damage, and thermal expansion coefficient differences.

Innovation Solution

A composition for an encapsulant comprising a first copolymer, a silicone urethane methacrylate-based polymer, and photoinitiators, which forms a curable system that effectively blocks oxygen and moisture, providing flexibility and improved sensitivity through the use of both D-type and T-type silicone resins.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If glass cap encapsulation is used, then moisture and oxygen blocking performance is improved, but manufacturing cost increases and flexibility is reduced

Engineering Contradiction:

Improvemoisture and oxygen blocking performanceVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a flexible polymer encapsulation layer comprising silicone-based polymers and other functional polymers that can effectively block moisture and oxygen while maintaining flexibility. This flexible film structure eliminates the need for rigid glass caps, thereby reducing manufacturing costs associated with glass processing and enabling flexible OLED panel production while preserving the essential protection function.

Inventive Principle:

Principle #30Flexible shells and thin films

2Reliability

If metal cap encapsulation is used, then moisture and oxygen blocking performance is improved, but thermal expansion mismatch problems occur

Engineering Contradiction:

Improvemoisture and oxygen blocking performanceVSAvoidthermal expansion coefficient compatibility

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The flexible polymer encapsulation layer has inherent flexibility and can accommodate thermal expansion differences between the OLED panel and encapsulation materials. The polymer matrix absorbs thermal stress through its viscoelastic properties, preventing the cracking and delamination issues that occur with rigid metal caps during thermal cycling.

Inventive Principle:

Principle #30Flexible shells and thin films

3Ease of manufacture

If laminating method is used, then ease of manufacture is improved, but moisture and oxygen permeation through adhesive interface occurs

Engineering Contradiction:

Improveease of manufactureVSAvoidmoisture and oxygen blocking performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent uses a composite encapsulation system where multiple polymer layers with different functions are combined. The first polymer layer provides primary barrier function, the second polymer layer provides additional protection and adhesion, and the third polymer layer provides surface protection. This multi-layer composite structure eliminates the need for separate adhesive layers, preventing moisture and oxygen permeation at interfaces while maintaining manufacturing simplicity.

Inventive Principle:

Principle #40Composite materials

4Strength

If sand blast or etching method is used for bonding, then bonding strength is improved, but device complexity and processing difficulty increase

Engineering Contradiction:

Improvebonding strengthVSAvoidprocessing complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The flexible polymer encapsulation layer provides inherent adhesion to the OLED panel through its viscoelastic properties and chemical composition, eliminating the need for sand blasting or etching processes. The polymer material can conform to the substrate surface and form strong bonds through van der Waals forces and chemical interactions, achieving adequate bonding strength without adding complex surface treatment steps.

Inventive Principle:

Principle #30Flexible shells and thin films

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 lifespan of organic electronic devices by effectively blocking external moisture and oxygen, while offering flexibility and strength, minimizing outgassing effects and enabling efficient UV curing.

Implementation Method 1

one or more photoinitiators

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

use of both D-type and T-type silicone resins

Methodology Applied

Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentUS10836907B2Composition for organic electronic element encapsulant and encapsulant formed using same

Publication Date: 2020.11.17 MOMENTIVE PERFORMANCE MATERIALS INC

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 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 silicone urethane methacrylate-based polymer comprising the second unit represented by Chemical Formula 2 as a main unit; and 3) one or more photoinitiators.