OLED Packaging Isolation Layer for Bending Stress Relief
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Solution Overview
Problem
Large-sized OLED devices face damage due to tangential pull stress between resin adhesive and passivation layers during bending, leading to peeling off of the passivation layer, especially in multi-layered structures.
Innovation Solution
A packaging assembly with an isolation layer between the bonding and protective layers, where the adhesion force between the isolation and bonding layers is lower than between the protective and bonding layers, and the isolation layer is designed as an arc-shaped structure or round pattern with specific spacing to distribute stress evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a passivation layer is added between the OLED device and resin adhesive to prevent direct contact and enhance blocking effect, then the protection against water and oxygen is improved, but tangential pull stress causes the passivation layer to peel off during bending
Solution Approach 1:
The patent introduces an isolation layer as an intermediary between the passivation layer and the bonding layer. This isolation layer has controlled adhesion properties - weak adhesion to the passivation layer and strong adhesion to the bonding layer - thereby mediating the stress transmission and preventing direct peeling between the passivation layer and OLED device while maintaining the protective function.
Solution Approach 2:
The isolation layer is applied locally at specific positions where bending stress is most concentrated, rather than uniformly across the entire surface. This localized application allows the structure to maintain strong adhesion in non-stress areas while providing stress relief only where needed, preserving overall adhesion strength while preventing peeling at critical points.
2Reliability
If the passivation layer is made as a multi-layered structure to enhance protection, then the blocking effect is improved, but pull stress causes the layers to separate from each other
Solution Approach 1:
The isolation layer acts as a stress-absorbing intermediary that prevents direct stress transmission between the multiple layers of the passivation structure. By positioning the isolation layer between the passivation layer and bonding layer, it mediates the interlayer stress and prevents delamination while maintaining the integrity of the multi-layered blocking structure.
3Reliability
If resin adhesive is used for surface-to-surface packaging of large-sized OLED devices, then the packaging effect is improved, but bending the device generates great difference in Young's modulus between resin adhesive and passivation layer causing tangential pull stress
Solution Approach 1:
The isolation layer serves as a mediator between the resin adhesive (bonding layer) and the passivation layer. It has controlled adhesion properties that allow it to bond strongly to the resin adhesive while having weaker adhesion to the passivation layer, thereby absorbing and distributing the tangential pull stress generated during bending and preventing direct stress transmission that would cause peeling.
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
This configuration reduces tangential stress and minimizes the risk of peeling off the protective layer from the OLED device, enhancing the packaging effect and durability of OLED devices, especially in flexible or curved OLED display panels.
Implementation Method 1
an adhesion force between the material for forming the isolation layer and that for forming the bonding layer is smaller than an adhesion force between the material for forming the protective layer and that for forming the bonding layer
Data Source
AI summary
The present disclosure provides a packaging assembly and a manufacturing method thereof. The packaging assembly comprising a first substrate, a second substrate arranged opposite to the first substrate, an electronic device located between the first substrate and the second substrate, a protective layer covering the electronic device, and a bonding layer for bonding the first substrate and the second substrate so as to realize surface-to-surface packaging. The packaging assembly further comprising an isolation layer located between the bonding layer and the protective layer and adhered to both them, wherein an adhesion force between the material for forming the isolation layer and that for forming the bonding layer is smaller than an adhesion force between the material for forming the protective layer and that for forming the bonding layer.