Self-Healing Organic Barrier Layer for OLED Crack Resistance
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Solution Overview
Problem
Organic light emitting diode (OLED) display devices face deterioration due to oxygen and moisture permeation, especially in flexible panels where cracks in the barrier layer can lead to electrode breakage and emission property degradation.
Innovation Solution
Incorporating a self-healing material in the organic layer of the barrier and filler layers, which initiates a chemical reaction upon crack formation to fill and prevent crack extension, using chemically reactive polymers such as acrylic or epoxy monomers with polymerization initiators, and potentially micro capsules to accelerate healing before oxygen and moisture permeation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a barrier layer with lamination structure is used to prevent oxygen and moisture permeation, then the emission property is maintained, but cracks in the barrier layer cause electrode breakage and emission deterioration
Solution Approach 1:
The organic layer is designed to automatically heal cracks through self-alignment and flow of organic material when cracks occur in the barrier layer, without requiring external intervention. This self-healing mechanism maintains the protective function of the barrier layer and prevents electrode breakage, resolving the contradiction between maintaining emission property and resisting cracks.
Solution Approach 2:
The organic layer is positioned and configured in advance to serve as a cushioning layer that can deform and flow to fill cracks in the barrier layer before they propagate to the electrode. This pre-positioned protective mechanism prevents harmful effects before they occur, maintaining both crack resistance and emission property.
2Reliability
If the barrier layer is made thicker to prevent oxygen and moisture permeation, then permeation is reduced, but flexibility and bendability are compromised
Solution Approach 1:
The patent uses a thin organic layer with self-healing properties instead of a thick rigid barrier layer. This thin film maintains flexibility and bendability while the self-healing capability ensures long-term permeation resistance, resolving the contradiction between permeation protection and flexibility for flexible displays.
3Reliability
If sealing layers and sealants are added to block oxygen and moisture contact, then permeation is prevented, but device complexity increases
Solution Approach 1:
The organic layer performs multiple functions simultaneously: it serves as the light-emitting functional layer of the OLED and also acts as a crack-healing protective layer for the barrier layer. This multi-functionality eliminates the need for additional sealing layers and sealants, reducing device complexity while maintaining permeation resistance.
Solution Approach 2:
The protective function is merged with the existing organic light-emitting layer rather than being separated into an additional component. This integration maintains the simplicity of the device structure while achieving effective crack healing and permeation prevention.
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
Prevents oxygen and moisture permeation even when cracks occur in the barrier layer, maintaining the emission properties of OLEDs and extending the device's lifespan by healing cracks within several hours to days.
Implementation Method 1
Incorporating a self-healing material in the organic layer of the barrier and filler layers, which initiates a chemical reaction upon crack formation to fill and prevent crack extension, using chemically reactive polymers such as acrylic or epoxy monomers with polymerization initiators
Data Source
AI summary
A display device includes: a substrate; a thin film transistor on the substrate; a first electrode, a light emitting diode and a second electrode sequentially on the thin film transistor; a barrier layer on the second electrode, the barrier layer including at least one organic layer; and a front film on the barrier layer, wherein the at least one organic layer includes a chemically self-healing material.