Flexible OLED Package With Sacrificial Layer
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Solution Overview
Problem
Flexible substrates used in OLED devices suffer from poor resistance to heat, moisture, oxygen, and chemicals, leading to accelerated aging and delamination issues when bent, which affects the device's operational reliability and longevity.
Innovation Solution
A package design incorporating a flexible substrate with a sacrificial layer composed of organic small molecular materials or oligomers, which has a lower bonding strength than the environmental sensitive element's thin films, to mitigate delamination and enhance durability and light efficiency when the device is bent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible substrate is used in OLED devices, then flexibility and ease of carriage are improved, but resistance to heat, moisture, oxygen, and chemicals deteriorates leading to accelerated aging
Solution Approach 1:
The patent introduces a sacrificial layer as an intermediary component between the flexible substrate and the OLED structure. This sacrificial layer has controlled bonding strength that is weaker than the OLED thin films, allowing it to serve as a buffer that protects the OLED structure during bending while maintaining the flexibility benefits of the flexible substrate.
Solution Approach 2:
The sacrificial layer is designed as a disposable, sacrificial component that is intended to fail or delaminate preferentially during bending events. By using a material with controlled, lower bonding strength, the sacrificial layer sacrifices itself to protect the more valuable OLED structure, allowing the device to maintain flexibility while preventing damage to the light-emitting components.
2Adaptability or versatility
If the flexible substrate is bent, then flexibility is demonstrated, but the OLED structure is damaged by bending force
Solution Approach 1:
The sacrificial layer is positioned and designed beforehand to provide cushioning protection during bending events. Its controlled bonding strength ensures that it will delaminate or fail first, absorbing the mechanical stress and preventing direct transmission of bending forces to the OLED structure, thereby protecting the device during flexing operations.
Solution Approach 2:
The sacrificial layer acts as a mechanical intermediary between the flexible substrate and the OLED structure. During bending, it mediates the stress distribution by delaminating preferentially, allowing the OLED structure to maintain its integrity while the flexible substrate continues to provide bending capability.
3Reliability
If the bonding strength of the sacrificial layer is lower than the OLED thin films, then delamination is prevented during bending, but the sacrificial layer may delaminate under normal conditions
Solution Approach 1:
The sacrificial layer is designed with spatially varying properties - its bonding strength is specifically engineered to be lower than the OLED thin films at the interface with the flexible substrate, while maintaining sufficient adhesion to the OLED structure. This local differentiation in bonding characteristics allows preferential delamination at the sacrificial layer interface during bending, while maintaining overall structural stability under normal operating conditions.
Data Source
AI summary
A package of an environmental sensitive element including a flexible substrate, an environmental sensitive element, at least one flexible sacrificial layer and a packaging structure is provided. The environmental sensitive element is disposed on the flexible substrate. The flexible sacrificial layer is disposed on the environmental sensitive element, wherein the environmental sensitive element includes a plurality of first thin films and the flexible sacrificial layer includes a plurality of second thin films. The bonding strength between two adjacent second thin films is equal to or lower than the bonding strength between two adjacent first thin films. Further, the packaging structure covers the environmental sensitive element and the flexible sacrificial layer.