Aluminum Oxide Encapsulation for OLED Moisture Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic light emitting displays are susceptible to damage from moisture and oxygen, leading to cracking and reduced lifespan, particularly in flexible devices, due to the thickness and material requirements of existing packaging methods which increase volume and material costs.
Innovation Solution
An organic light emitting display with a minimized upper encapsulation layer made of aluminum oxide-based material, formed in a single layer with a Water Vapor Transmission Rate (WVTR) of ≤10^-2 g/m²/day, and a thickness of 20 to 50 nm, which prevents oxygen and moisture permeation and reduces the risk of cracking upon bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective cap made of metal or glass is used to seal the substrate, then the organic layer is protected from oxygen and moisture, but the volume and thickness of the display increase and flexibility is reduced
Solution Approach 1:
The patent extracts the essential protective function from the bulky protective cap structure and implements it through a thin barrier layer formed directly on the substrate. This eliminates the need for a separate thick protective cap while maintaining the core protection function against oxygen and moisture.
Solution Approach 2:
The patent employs a thin barrier layer (thin film) instead of a thick protective cap. This thin film structure provides the necessary protection while maintaining flexibility and reducing volume, directly addressing the contradiction between protection and flexibility/thickness.
2Reliability
If a barrier layer is formed by stacking multiple inorganic insulating films and organic insulating films, then moisture and oxygen permeation is blocked, but the thickness increases and cracks may occur during bending
Solution Approach 1:
The patent merges multiple separate barrier layers (inorganic and organic films) into a single integrated barrier layer. This consolidation maintains the blocking function against moisture and oxygen while eliminating the interfaces between layers that could become crack initiation points during bending.
Solution Approach 2:
The barrier layer is formed using a composite structure combining inorganic insulating film and organic insulating film in a single integrated layer. This composite material approach provides both the moisture/oxygen blocking capability and the flexibility needed to prevent cracking during bending operations.
3Reliability
If a protective cap with moisture absorbent and semi-permeable membrane is used, then moisture and oxygen are absorbed and filtered, but additional materials increase cost and complexity
Solution Approach 1:
The patent extracts the moisture absorption and oxygen filtration functions from the complex protective cap assembly with moisture absorbents and semi-permeable membranes. These functions are integrated directly into the barrier layer formed on the substrate, eliminating the need for separate components.
Solution Approach 2:
The barrier layer is designed to perform multiple functions simultaneously: blocking moisture permeation, blocking oxygen permeation, and providing mechanical strength. This multi-functionality eliminates the need for separate moisture absorbents and semi-permeable membranes, reducing overall device complexity.
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 minimizes substrate damage during bending, reduces material costs, and simplifies the manufacturing process by using a thin, high-density aluminum oxide encapsulation layer that maintains excellent moisture and oxygen barrier properties.
Implementation Method 1
a barrier layer disposed on the adhesive layer and encapsulating the organic light emitting device (OLED)
Data Source
AI summary
The present disclosure provides an organic light emitting display that may comprise: an organic light emitting device (OLED) including a first electrode, an organic layer including a light-emitting layer, and a second electrode, which are sequentially formed on a substrate having a Thin Film Transistor (TFT) formed on the substrate; and an upper encapsulation layer, which is formed of an aluminum oxide-based material, is formed in a single layer, and is disposed on the substrate on which the organic light emitting device (OLED) is formed, wherein a Water Vapor Transmission Rate (WVTR) of the upper encapsulation layer is smaller than or equal to 10−2 g/m2/day.