Polymeric Decoupling Layer for OLED Encapsulation
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Solution Overview
Problem
Existing encapsulation methods for environmentally sensitive devices, such as OLEDs, face challenges due to plasma damage during the deposition of barrier and decoupling layers, leading to degradation and reduced performance, with conventional decoupling layers failing to provide adequate barrier performance and compatibility with deposition technologies.
Innovation Solution
A method involving the use of polymeric decoupling layers made from blends of 60-90 wt% dimethacrylate, 0-20 wt% monoacrylate, 5-20 wt% triacrylate, and 1-10 wt% photoinitiator, which are designed to minimize plasma damage, mechanical stress, and water permeability, enhancing the overall barrier performance and compatibility with various deposition processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plasma-based deposition processes are used to deposit barrier and decoupling layers, then barrier performance is improved, but plasma damage occurs to the environmentally sensitive device
Solution Approach 1:
A plasma-resistant decoupling layer is introduced as an intermediary between the plasma deposition process and the environmentally sensitive device. This decoupling layer acts as a protective mediator that allows plasma-based barrier layer deposition while preventing direct plasma damage to the device, thereby maintaining barrier performance without compromising device integrity
Solution Approach 2:
The decoupling layer is designed with specific local properties (plasma resistance, appropriate thickness, material composition) that differ from both the barrier layer and the device structure. This localized quality enhancement at the interface region protects the device from plasma damage while maintaining overall barrier stack functionality
2Reliability
If conventional decoupling layers are used, then device encapsulation is achieved, but adequate barrier performance and compatibility with deposition technologies are not provided
Solution Approach 1:
The decoupling layer is designed to perform multiple functions simultaneously: it serves as a protective barrier during plasma deposition, provides mechanical stress relief, maintains structural integrity, and ensures compatibility with various deposition technologies. This multi-functionality enables the encapsulation system to achieve both adequate barrier performance and broad deposition technology compatibility
3Reliability
If barrier stacks with multiple layers are deposited to improve barrier performance, then water vapor and oxygen permeation resistance is enhanced, but mechanical stress and plasma damage increase
Solution Approach 1:
The barrier stack is segmented into distinct functional layers: a plasma-resistant decoupling layer and a barrier layer. This segmentation allows each layer to be optimized for its specific function while reducing overall mechanical stress and plasma damage exposure, as the decoupling layer absorbs stress and protects the device during deposition of subsequent barrier layers
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 proposed solution significantly reduces plasma damage and mechanical stress, improves barrier performance, and maintains the electroluminescence and appearance of encapsulated devices, while also addressing issues of water permeability and structural stability, resulting in enhanced longevity and reliability of encapsulated devices.
Implementation Method 1
a blend of polymer precursors comprising 60 to 90 wt% of a dimethacrylate, 0 to 20 wt% of a monoacrylate, 5 to 20 wt% of a triacrylate, and 1 to 10 wt% of a photoinitiator
Implementation Method 2
The barrier stacks typically include at least one barrier layer and at least one decoupling layer... preventing environmental oxygen and water vapor from degrading the display device
Data Source
Figure 1~2B
Figure 3A~3D
Figure 4A~4C
AI summary
A method of encapsulating an environmentally sensitive device. The method includes providing a substrate; placing at least one environmentally sensitive device adjacent to the substrate; and depositing at least one barrier stack adjacent to the environmentally sensitive device, the at least one barrier stack comprising at least one barrier layer and at least one polymeric decoupling layer, wherein the at least one polymeric decoupling layer is made from at least one polymer precursor, and wherein the polymeric decoupling layer has at least one of: a reduced number of polar regions; a high packing density; a reduced number of regions that have bond energies weaker than a C-C covalent bond; a reduced number of ester moieties; increased Mw of the at least one polymer precursor; increased chain length of the at least one polymer precursor; or reduced conversion of C=C bonds. An encapsulated environmentally sensitive device is also described.