OLED Display Panel Double-Layer Wiring for Bending Area Stress Relief
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Solution Overview
Problem
Conventional OLED display panels experience breakage and unstable connections of power supply, scan, and data wirings in bending areas due to stress on metal wirings, leading to instability and poor display quality.
Innovation Solution
The OLED display panel incorporates a double-layer wiring or double-layer wiring exchange structure with a first metal layer on the display area edge and a second metal layer in the bending area, electrically connected in parallel or series, using a dielectric layer and counterbores filled with organic insulating material to reduce stress and maintain signal transmission even if one layer breaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If straight metal wirings are used to connect drain electrodes of adjacent driving TFTs, then the wiring structure is simple, but the wirings easily crack and lead to excessively high local resistance and disconnection in bending areas
Solution Approach 1:
The patent divides the metal wiring into multiple segments by creating counterbores along the bending path. These counterbores segment the continuous stress path, preventing crack propagation through the entire wiring length. The wiring is effectively divided into multiple shorter segments that can independently accommodate bending stress without causing complete disconnection.
Solution Approach 2:
The patent applies beforehand cushioning by filling the counterbores with organic insulating material before the wiring is subjected to bending stress. This pre-filled material acts as a cushion that absorbs and distributes the mechanical stress, preventing the wiring from cracking under subsequent bending operations. The cushioning material is positioned in advance to protect the wiring from future stress exposure.
2Strength
If counterbores are formed in the bending area and filled with organic insulating material to reduce stress on metal wirings, then wiring stress is reduced, but bumps are formed on the surface that affect connection stability of power supply wirings, scan wirings, and data wirings
Solution Approach 1:
The patent applies local quality by making the counterbore depth and filling material properties location-specific. The counterbores are strategically positioned and sized to provide stress relief only where needed (in the bending area), while maintaining flat surfaces in other areas for stable wiring connections. The organic insulating material is selectively applied to fill counterbores without creating surface bumps that would interfere with subsequent wiring layers.
Solution Approach 2:
The patent resolves the surface bump problem by transitioning to another dimension - specifically, by planarizing the surface after filling the counterbores. An additional organic insulating layer is deposited over the filled counterbores to create a flat top surface, effectively moving the stress relief function to the bulk material while maintaining a smooth external surface for stable wiring connections.
3Shape
If the display panel is bent to achieve narrow border, then the bezel is narrowed and foldability is improved, but the metal wirings in the bending area are subjected to excessive stress and prone to breakage
Solution Approach 1:
The patent segments the wiring structure by creating counterbores that divide the continuous metal wiring into multiple sections. This segmentation prevents stress concentration along the entire bending path, as each segment can independently accommodate local deformation without causing complete wiring failure. The segmented structure maintains electrical connectivity even when subjected to repeated bending cycles.
Solution Approach 2:
The patent changes the physical parameters of the wiring structure by modifying its cross-sectional geometry through counterbore formation. The counterbores create a hollow or partially filled structure that is more flexible and better able to accommodate bending deformation. This parameter change - from solid to hollow/partially-filled cross-section - fundamentally alters the wiring's mechanical properties to improve bendability while maintaining structural integrity.
Data Source
AI summary
The invention provides an organic light-emitting diode (OLED) display panel and a display device. Metal wiring is designed into a first metal layer and a second metal layer. The first metal layer is distributed on an edge of a display area and a bending area, the second metal layer is positioned in the bending area, and the second metal layer is disposed opposite to the first metal layer. A part of the first metal layer positioned in the bending area is electrically connected in parallel or in series with the second metal layer to form a double-layer wiring or a double-layer wiring exchange structure. After any one of the metal layers breaks, the other metal layer can still be used to maintain signal transmission.