Bent Display Conductive Layer Stress Management
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Solution Overview
Problem
The manufacturing process of bent display devices often results in defects, such as disconnection of the conductive layer, due to high tensile stress during bending, which reduces the lifespan of the device.
Innovation Solution
A display device design featuring a substrate with a bending area, an organic layer with an uneven surface, and a conductive layer with through holes synchronized to the protrusions or concave portions of the organic layer, which reduces tensile stress and minimizes the risk of defects by allowing deformation and increased flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conductive layer is made continuous and smooth to ensure good electrical conductivity, then electrical performance is improved, but tensile stress concentration during bending increases causing disconnection defects
Solution Approach 1:
The conductive layer is segmented into multiple discrete conductive patterns rather than a continuous layer. These segmented conductive elements are positioned to correspond with the protrusions of the organic layer, allowing the layer to flex and deform during bending without creating continuous stress paths that would lead to disconnection.
Solution Approach 2:
The conductive layer is designed with locally varying properties - the conductive patterns are strategically positioned to correspond with the protrusions of the organic layer in the bending area. This local positioning allows the conductive layer to maintain electrical functionality while accommodating the deformation characteristics of the underlying organic layer during bending.
2Ease of manufacture
If the organic layer surface is made smooth to simplify manufacturing, then manufacturing complexity is reduced, but stress distribution during bending is uneven causing defects
Solution Approach 1:
The organic layer is pre-formed with an uneven surface featuring protrusions before the conductive layer is deposited. This preliminary structuring of the organic layer surface allows subsequent alignment of conductive patterns to these protrusions, creating a stress-distributing configuration that prevents disconnection during bending.
Solution Approach 2:
The organic layer surface is intentionally given curvature through protrusions rather than being flat. These curved/uneven surface features correspond to the bending geometry and allow the conductive layer to follow the natural stress distribution patterns during bending, preventing stress concentration at flat surfaces.
3Reliability
If the conductive layer is made thick to improve conductivity, then electrical performance is improved, but flexibility during bending is reduced increasing disconnection risk
Solution Approach 1:
The conductive layer is divided into segmented patterns rather than a continuous thick layer. This segmentation maintains electrical conductivity through the patterned conductive elements while reducing overall material volume and improving flexibility, allowing the layer to bend without cracking or disconnecting.
Solution Approach 2:
The conductive layer is designed as a thin-film structure with patterns that correspond to the organic layer protrusions. This thin-film, patterned approach provides sufficient electrical conductivity while maintaining the flexibility needed to accommodate bending deformation without rigid stress concentration.
Data Source
AI summary
A display device includes: a substrate including a bending area located between a first region and a second region; an organic layer disposed over the substrate, an upper surface of the organic layer including an uneven surface in the bending area, the uneven surface including a plurality of protrusions; and a conductive layer extending from the first region to the second region across the bending area, the conductive layer being located over the organic layer and including a plurality of through holes.