Bending-Area Display Wiring Layout to Prevent Disconnection
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Solution Overview
Problem
Display devices with bending areas face defects such as disconnection during manufacturing due to tensile stress, particularly in the second wiring unit which includes power and driving circuit wirings, leading to potential fatal defects if power is not supplied or signals are not applied for driving the display.
Innovation Solution
The display device incorporates a substrate with a bending area where the second wiring unit has a pitch greater than the first wiring unit, with wider second wirings and a similar distance between them as the first wirings, reducing tensile stress and resistance, and includes sub-wirings connected in parallel to distribute stress and maintain minimum distance, thus reducing the likelihood of shorts and disconnections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the second wiring unit has a smaller pitch to reduce area, then the area is reduced, but tensile stress increases causing disconnection defects
Solution Approach 1:
The patent applies different pitch values to different wiring units: the first wiring unit (data signals) has a first pitch, while the second wiring unit (power and driving signals) has a second pitch greater than the first pitch. This local differentiation allows the power/driver wirings to have sufficient spacing to reduce tensile stress and prevent disconnection, while data wirings maintain tighter spacing to conserve area.
2Loss of energy
If the second wiring unit has wider wirings to reduce resistance, then resistance is reduced, but the area occupied increases
Solution Approach 1:
The patent differentiates wiring dimensions by function: second wirings (power and driving signals) have greater width to reduce resistance and ensure reliable power delivery, while first wirings (data signals) have smaller width since they carry low-current signals. This selective sizing optimizes energy efficiency for power-critical pathways without unnecessarily increasing total area.
3Reliability
If the pitch of the second wiring unit is increased to reduce tensile stress, then reliability is improved, but the area occupied increases
Solution Approach 1:
The patent implements functional differentiation in wiring spacing: the second wiring unit (power and driving signals) uses a larger second pitch to minimize tensile stress and prevent disconnection during bending, while the first wiring unit (data signals) uses a smaller first pitch to conserve area. This selective spacing strategy optimizes reliability for stress-prone power pathways without uniformly increasing the total wiring area.
Data Source
AI summary
A display device includes a substrate including a bending area located between a first area and a second area. The substrate is bent in relation to a bending axis. A first wiring unit including a plurality of first wirings is arranged on the substrate to sequentially extend over the first area, the bending area, and the second area. First central axes included in each of the plurality of first wirings are spaced apart from each other by a first pitch in the bending area. A second wiring unit including a plurality of second wirings is arranged on the substrate to sequentially extend over the first area, the bending area, and the second area. Second central axes included in each of the plurality of second wirings are spaced apart from each other by a second pitch greater than the first pitch in the bending area.