Stretchable Display Wiring Layout to Prevent Bridge Cracking
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Solution Overview
Problem
Stretchable display devices face defects such as wiring disconnection or cracking when the substrate is repeatedly stretched or contracted, due to the damage of light emitting elements and wirings on the flexible substrate.
Innovation Solution
A display device design featuring a base layer with islands and bridges, where the bridges connect the islands, and first and second wirings are connected through contact holes in organic and inorganic insulating layers, with the second wirings made of materials like niobium-aluminum or tantalum-aluminum, to minimize stress and prevent cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a stretchable substrate is used to enable bendable and foldable display devices, then adaptability and versatility are improved, but reliability deteriorates due to wiring disconnection and cracking during repeated stretching and contracting
Solution Approach 1:
The substrate is divided into multiple islands connected by bridges, creating a segmented structure that allows independent movement of each island during stretching, preventing continuous stress concentration along single wiring paths
Solution Approach 2:
Different regions of the substrate are given different properties: islands contain rigid inorganic insulating layers for stability, while bridges use flexible organic insulating layers for stretchability, creating localized functional zones that resolve the contradiction between rigidity and flexibility
2Manufacturing precision
If inorganic insulating layers are disposed on bridges to provide insulation, then manufacturing precision is improved, but reliability deteriorates due to cracking of rigid inorganic layers during stretching
Solution Approach 1:
The insulating layer structure is segmented into region-specific compositions: inorganic insulating layers are formed only on islands where rigidity is needed, while bridges use organic insulating layers that can stretch without cracking
Solution Approach 2:
The insulating layer has different material compositions in different locations: inorganic materials (silicon oxide, silicon nitride) on islands provide precise insulation and structural stability, while organic materials (polyimide, polyacrylonitrile) on bridges provide flexibility and crack resistance during stretching
Data Source
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AI summary
A display device comprises: a base layer, islands and bridges, the islands and the bridges disposed on the base layer, the bridges connecting the islands to each other, first wirings disposed on the bridges, pixels disposed on the islands, the first wirings disposed on the bridges, pixels disposed on the islands, the first wirings being connected to the pixels; an inorganic insulating layer disposed on the base layer, the inorganic insulating layer includes an opening exposing the base layer of a bridge region having the bridges; second wirings disposed in the opening; and a first organic insulating layer disposed between the first wirings and the second wirings, where the first wirings and the second wirings are connected to each other through first contact holes formed in the first organic insulating layer.