Cross-Bending Connection Electrode Structure for Flexible Displays
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Solution Overview
Problem
Connection electrodes in display apparatuses disconnect due to bending stress and external impact, leading to instability in the connection between the display and pad areas.
Innovation Solution
A display apparatus design featuring a crack preventing layer with overlapping connecting electrodes and a connection contact hole to stabilize the connection across a bending area, utilizing a stacked structure of lower and upper connecting electrodes with shared materials and a crack preventing layer to enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single connection electrode is used to connect the display area and pad area across the bending area, then the device structure is simple, but the connection electrode disconnects due to bending stress and external impact
Solution Approach 1:
The connection electrode is divided into multiple segments (first connection electrode, second connection electrode, third connection electrode) arranged in series across the bending area. Each segment can independently accommodate bending stress, preventing disconnection while maintaining electrical connectivity between the display area and pad area.
Solution Approach 2:
The connection electrodes are arranged in a nested configuration where the first, second, and third connection electrodes are positioned overlapping each other across the bending area. This nested arrangement provides redundant pathways for electrical connection, ensuring that if one electrode segment experiences stress, the others maintain connectivity.
2Adaptability or versatility
If the device substrate is made flexible to enable bending, then the device can be folded or curved, but the connection electrode becomes vulnerable to disconnection
Solution Approach 1:
The connection electrode structure is designed to be dynamic rather than rigid, with multiple flexible segments that can adapt to bending movements. The segmented electrodes can deform elastically with the flexible substrate during bending while maintaining electrical continuity, accommodating the dynamic nature of flexible display applications.
Solution Approach 2:
The connection electrodes are implemented as thin film structures that conform to the flexible substrate. These thin film electrodes can bend and deform with the flexible substrate without cracking or disconnecting, maintaining electrical connectivity throughout the bending cycle.
3Reliability
If a crack preventing layer is added to protect the connection electrode, then the connection stability improves, but the device structure becomes more complex
Solution Approach 1:
The connection electrode structure employs composite material layers including the first connection electrode layer, second connection electrode layer, third connection electrode layer, and crack preventing layer. Each layer contributes specific properties (conductivity, flexibility, crack resistance) to create a composite structure that achieves superior reliability while managing the complexity through functional integration.
Data Source
AI summary
A display apparatus having a connection electrode which crosses a bending area may be provided. The connection electrode may be disposed on a device substrate including a bending area between a display area and a pad area. The connection electrode may connect the display area and the pad area across the bending area. The connection electrode may have a stacked structure of the lower connecting electrode and the upper connecting electrode. A light-emitting device, an encapsulating element and a touch electrode may be sequentially stacked on the display area of the device substrate. The upper connecting electrode may include the same material as the touch electrode. Thus, in the display apparatus, the disconnection of the connection electrode due to bending stress and external impact may be reduced.