Porous Encapsulation Layer Diffuses Impurities in OLED
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Solution Overview
Problem
Organic light emitting display apparatuses are prone to degradation due to sensitivity to moisture, oxygen, and light, leading to reduced lifespan and the formation of dark spots, as these impurities can penetrate and concentrate, causing electrochemical charge transfer reactions and oxide generation between electrodes and the organic layer.
Innovation Solution
The implementation of a porous layer with a path for even diffusion of impurities, combined with a planarization layer of organic material and a barrier layer of inorganic material such as AlOx, Al2O3, or ZnO, to prevent concentration of impurities and extend the lifespan by delaying the revelation of progressive dark spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encapsulation technology is used to prevent moisture and oxygen from intruding, then the device is protected from degradation, but impurities can still concentrate at certain parts causing dark spots
Solution Approach 1:
The patent introduces a porous layer within the encapsulation structure that allows impurities to diffuse evenly throughout the layer rather than concentrating at specific locations. The porous structure provides multiple pathways for impurity distribution, preventing localized accumulation that would otherwise cause dark spots while maintaining the overall protective function against moisture and oxygen.
Solution Approach 2:
The porous layer acts as an intermediary between the encapsulation barrier and the organic light emitting layer. It mediates the interaction by allowing controlled diffusion of impurities through its porous structure, preventing direct contact and concentration at critical interfaces, thus delaying dark spot formation while maintaining encapsulation effectiveness.
2Duration of action of stationary object
If the device is protected from external impurities, then lifespan is extended, but internal impurities from the planarization layer can still degrade the device
Solution Approach 1:
The porous layer serves as an intermediary buffer between the planarization layer (source of internal impurities) and the organic light emitting layer. It allows impurities to diffuse through its porous structure in a controlled manner, preventing sudden concentration and damage, thereby extending device lifespan despite the presence of internal impurity sources.
Solution Approach 2:
The patent converts the potentially harmful effect of impurity concentration into a beneficial diffusion process. By providing a porous structure, impurities that would otherwise cause localized damage are instead distributed evenly throughout the porous layer, transforming a harmful concentration effect into a benign distributed presence that delays degradation.
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 effectively diffuses impurities into the porous layers, preventing their concentration and thereby extending the life of the organic light emitting display apparatus by delaying the appearance of dark spots, thus enhancing the durability and performance of the device.
Implementation Method 1
The porous layer prevents impurities, intruding into the porous layer, from being concentrated at a part of the porous layer by diffusing the impurities into the porous layer
Data Source
AI summary
An organic light emitting display apparatus including a substrate, an organic light emitting portion comprising a plurality of organic light emitting devices formed on the substrate, and an encapsulation portion for encapsulating the organic light emitting portion. The encapsulation portion includes a porous layer formed on the organic light emitting portion, a planarization layer formed on the porous layer, and a barrier layer formed on the planarization layer. The porous layer prevents impurities from being concentrated at a part of the porous layer.