Flexible Display Crack Prevention via Bending Line Alignment
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Solution Overview
Problem
Display devices with side portions face bending stress issues, particularly at oblique directions, which can lead to crack propagation and defects due to dual bending at intersection points, affecting the screen ratio and reliability.
Innovation Solution
A display device design featuring a display panel with specific bending lines and a crack propagation prevention pattern on a flexible substrate, including organic layers and insulating layers, to absorb or attenuate cracks at high-risk areas, and align marks for precise alignment, reducing bending stress and preventing crack propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the display panel includes side portions bent in oblique directions to increase screen ratio, then the display area is expanded, but bending stress concentrates at intersection points causing crack propagation
Solution Approach 1:
The display panel is divided into multiple regions: a flat portion, first and second side portions bent along bending lines, and a third side portion at the corner. This segmentation allows stress to be distributed across different bending zones rather than concentrating at a single point, reducing crack propagation risk while maintaining expanded display area.
Solution Approach 2:
The corner portion (third side portion) is given special structural treatment with rounded corners and specific bending radius requirements. This local quality enhancement addresses the high-stress concentration zone at the intersection of bending lines, improving crack resistance precisely where needed without affecting other areas of the display panel.
2Area of stationary object
If bending lines are extended to increase display area coverage, then screen ratio is improved, but stress concentration at intersection points increases
Solution Approach 1:
The bending lines are designed with specific curvature radii rather than sharp angles. The first bending line has a first curvature radius and the second bending line has a second curvature radius, with the corner portion having a rounded shape. This curvature distribution reduces stress concentration at intersection points while still achieving extended display area coverage.
3Ease of manufacture
If the display panel structure is simplified for ease of manufacture, then manufacturing cost is reduced, but crack propagation prevention capability is weakened
Solution Approach 1:
The bending lines and corner portions are pre-designed with specific geometric parameters (curvature radii, bending angles) during the manufacturing process. This preliminary action ensures that stress distribution is optimized from the outset, providing crack propagation resistance without requiring complex additional manufacturing steps or assemblies.
Data Source
AI summary
A display device includes a display area including a corner portion, a display panel including a non-display area located around the display area, and a cover window disposed on the display panel. The display panel includes a flexible substrate, and a crack propagation prevention pattern including a first organic layer disposed on the flexible substrate and directly contacting the flexible substrate. The intersecting point of a bending line overlaps with the crack propagation prevention pattern in the a thickness direction. In addition, the display device further includes alignment marks which overlap with the bending line.