Flexible OLED Encapsulation Adhesion Supporter

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Solution Overview

Problem

The existing encapsulation structures for flexible organic light emitting display apparatuses are prone to delamination and detachment due to weak adhesive strength between the flexible encapsulation layer and the pressure sensitive adhesive layer, especially when bent, leading to reduced lifetime and reliability.

Innovation Solution

A flexible organic light emitting display apparatus with a silicon-based adhesion supporter layer between the aluminum oxide encapsulation layer and the pressure sensitive adhesive layer, enhancing the adhesive strength and preventing delamination, and a triple-layer encapsulation structure with a foreign material compensation layer to improve water and oxygen barrier performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a multi-layer encapsulation structure with repeated silicon-based organic and inorganic insulation layers is used, then water permeation delay performance is improved, but the encapsulation part becomes thick and prone to cracking when bent

Engineering Contradiction:
Improvewater permeation delay performanceVSAvoidencapsulation part thickness
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses a composite encapsulation structure combining an inorganic encapsulation layer (alumina formed by ALD) with an organic flexible encapsulation layer. This composite approach provides excellent water permeation delay performance while maintaining flexibility and preventing cracks during bending, resolving the contradiction between reliability and device complexity.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a flexible encapsulation layer with aluminum oxide is used, then water permeation delay ability is improved, but adhesive strength between the encapsulation layer and pressure sensitive adhesive layer becomes weak, causing delamination when bent

Engineering Contradiction:
Improvewater permeation delay abilityVSAvoidadhesive strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent introduces an adhesion supporter layer as an intermediary between the inorganic encapsulation layer and the pressure sensitive adhesive layer. This intermediate layer improves adhesive strength and prevents delamination during bending, while maintaining the excellent water permeation delay ability of the aluminum oxide encapsulation layer.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If the encapsulation part is made thin for flexibility, then ease of bending is improved, but crack resistance deteriorates

Engineering Contradiction:
ImproveflexibilityVSAvoidcrack resistance
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent employs a flexible organic encapsulation layer that can be formed thin while maintaining integrity. Combined with the ALD-formed inorganic encapsulation layer and adhesion supporter, this flexible film structure provides both the needed flexibility for bending and sufficient crack resistance to prevent delamination and maintain water barrier performance.

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 solution significantly increases the adhesive strength between the encapsulation and barrier films, preventing detachment and enhancing the display's water vapor transmission rate, thus improving the apparatus's reliability and lifetime, even when bent.

Implementation Method 1

a flexible encapsulation layer comprising at least one aluminum oxide layer which delays a permeation of water

Methodology Applied
Scientific EffectPermeation delay: Permeation

Implementation Method 2

an adhesion supporter which increases an adhesive strength of an interface between the flexible encapsulation layer and the pressure sensitive adhesive layer

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2950363B1Organic light emitting display apparatus
Publication Date: 2017.07.05 LG DISPLAY CO LTD
  • EP2950363B1 patent drawingFigure 1~2A
  • EP2950363B1 patent drawingFigure 2B~2C
  • EP2950363B1 patent drawingFigure 2D~2E

AI summary

A flexible organic light emitting display apparatus (100) comprising a flexible encapsulation layer (130) comprising at least one aluminum oxide layer configured to cover an area having a plurality of pixels (PA), a flexible barrier film (150) comprising a flexible barrier film body (152) and a pressure sensitive adhesive layer (151) on the flexible encapsulation layer (130) and an adhesion supporter (140) directly contacting the aluminum oxide layer and the pressure sensitive adhesive layer (151).