Foldable Display Adhesive Corners for Drop Stress Relief
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Solution Overview
Problem
Foldable display devices face challenges in maintaining structural integrity and reliability due to concentrated stress during folding and dropping, which can lead to damage.
Innovation Solution
The design incorporates a support member with adhesive layers having corners and chamfers adjacent to the folding area, distributing stress and improving dropping performance by removing adhesive layers from the folding area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive layers are disposed continuously across the support member including the folding area, then bonding strength is improved, but stress concentration during folding and dropping occurs leading to structural damage
Solution Approach 1:
The adhesive layer is extracted from the folding area to prevent stress concentration during folding operations. The adhesive layer is disposed only on flat areas adjacent to the folding area, completely removing it from the folding region where stress concentration would occur during bending and dropping events.
Solution Approach 2:
The adhesive layer is strategically positioned with different presence patterns in different regions: it is present on flat areas for bonding support, but absent from the folding area to allow stress-free bending. This local differentiation optimizes both bonding strength where needed and structural integrity where folding occurs.
2Reliability
If adhesive layers are removed from the folding area to improve dropping performance, then stress distribution is improved, but bonding strength in the folding region is reduced
Solution Approach 1:
The adhesive layer is extracted from the folding area to prevent stress concentration during folding operations. The adhesive layer is disposed only on flat areas adjacent to the folding area, completely removing it from the folding region where stress concentration would occur during bending and dropping events.
Solution Approach 2:
The adhesive layer is strategically positioned with different presence patterns in different regions: it is present on flat areas for bonding support, but absent from the folding area to allow stress-free bending. This local differentiation optimizes both bonding strength where needed and structural integrity where folding occurs.
3Reliability
If corners of adhesive layers are designed with large radius of curvature to distribute stress, then stress concentration is reduced, but manufacturing precision requirements increase
Solution Approach 1:
Corners of the adhesive layer are designed with rounded geometry having a radius of curvature between 2mm to 4mm. This curvature prevents stress concentration at sharp corners during folding and dropping, distributing mechanical stresses more evenly across the adhesive layer boundaries.
Solution Approach 2:
The corner geometry parameters are specifically controlled with radius of curvature in the range of 2mm to 4mm, which is optimized to balance stress distribution benefits with manufacturing feasibility. This parameter optimization reduces stress concentration while maintaining reasonable manufacturing precision requirements.
Data Source
AI summary
A foldable display device includes a support member divided into a folding area and at least one flat area adjacent to the folding area, at least one adhesive layer disposed on the support member, overlapping the at least one flat area, and including at least one corner adjacent to the folding area, and a display device disposed on the at least one adhesive layer. A radius of curvature is defined at the at least one corner.