Flexible Display Adhesive Layer Structure for Folding Reliability
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Solution Overview
Problem
Flexible displays in foldable or rollable electronic devices are prone to film layer separation and adhesive failure due to repeated deformation, leading to low reliability and a shortened service life.
Innovation Solution
The electronic device incorporates an adhesive layer assembly with strong and weak adhesive layers, where the strong adhesive layers have higher stiffness than the weak layers, strategically positioned to minimize dislocation and stress during folding, thereby reducing the risk of arching, film layer separation, and adhesive failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single adhesive layer is used to bond the flexible display to the housing assembly, then the structure is simple, but the reliability is low due to film layer separation and adhesive failure during repeated deformation
Solution Approach 1:
The adhesive layer is segmented into multiple functional layers: a first adhesive layer for bonding the flexible display to the housing assembly, and a second adhesive layer for bonding the support to the flexible display. This segmentation allows each layer to be optimized for its specific function, preventing film layer separation and adhesive failure during repeated deformation while maintaining structural integrity.
Solution Approach 2:
The adhesive structure uses composite adhesive layers with different material properties. The first adhesive layer has higher stiffness to maintain bonding strength, while the second adhesive layer has lower stiffness to accommodate deformation. This composite approach prevents adhesive failure and extends the service life of the flexible display.
2Reliability
If the flexible display is rigidly fixed to prevent dislocation, then film layer separation is reduced, but stress accumulation increases leading to adhesive failure
Solution Approach 1:
Different regions of the adhesive structure have different mechanical properties. The first adhesive layer has higher stiffness to prevent dislocation and film layer separation, while the second adhesive layer has lower stiffness to accommodate stress during deformation. This local differentiation of material properties allows the system to simultaneously prevent film layer separation and reduce stress accumulation.
Solution Approach 2:
The adhesive layers are designed with different stiffness parameters to optimize performance. The first adhesive layer has higher stiffness to maintain bonding strength and prevent dislocation, while the second adhesive layer has lower stiffness to accommodate deformation and reduce stress. This parameter optimization prevents both film layer separation and adhesive failure.
3Reliability
If the adhesive layer has high stiffness to prevent dislocation, then film layer separation is reduced, but the flexible display cannot fully restore during unfolding
Solution Approach 1:
The first adhesive layer has higher stiffness to prevent dislocation and maintain bonding strength, while the second adhesive layer has lower stiffness to allow the flexible display to fully restore during unfolding. This local differentiation of material properties enables the system to simultaneously achieve stability during folding and restoration capability during unfolding.
Solution Approach 2:
The adhesive structure uses different stiffness parameters for different layers. The first adhesive layer has higher stiffness to prevent dislocation and film layer separation, while the second adhesive layer has lower stiffness to accommodate the restoration movement of the flexible display during unfolding, preventing adhesive failure.
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 enhances the reliability of the flexible display by reducing dislocation and stress, prolonging the device's service life and improving user experience.
Implementation Method 1
One strong adhesive layer and one weak adhesive layer are bonded between the first non-bending part and the first housing, and the other strong adhesive layer and the other weak adhesive layer are bonded between the second non-bending part and the second housing
Implementation Method 2
the first non-bending part is bonded to the first housing by using the strong adhesive layer and the weak adhesive layer, and the second non-bending part is bonded to the second housing by using the strong adhesive layer and the weak adhesive layer
Data Source
AI summary
An electronic device includes a flexible display, a housing assembly, and an adhesive layer assembly fastened between the flexible display and the housing assembly. The adhesive layer assembly includes a strong adhesive layer and a weak adhesive layer, and a stiffness of the strong adhesive layer is higher than a stiffness of the weak adhesive layer. The strong adhesive layer and the weak adhesive layer are arranged to make the flexible display deform with the electronic device.