OLED Display Panel Neutral Layer Adjustment for Bending Reliability
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Solution Overview
Problem
OLED display panels with high Young's modulus flexible substrates are prone to stress damage and circuit breakage in bending areas due to the neutral layer's position below the signal wiring layer, leading to poor display performance.
Innovation Solution
A buffer layer with patterned holes is introduced over the flexible substrate in the bending region, adjusting the neutral layer's position into the signal wiring layer, and the Young's modulus of the substrate is reduced in the bending area to mitigate stress on the signal wiring, with polyimide and polyethylene terephthalate backplates providing support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a high Young's modulus flexible substrate is used, then structural strength is improved, but the neutral layer position moves below the signal wiring layer causing stress damage and circuit breakage in bending areas
Solution Approach 1:
The patent applies local quality by introducing a buffer layer with patterned holes specifically in the bending region, while maintaining the original substrate structure in other areas. This localized modification adjusts the neutral layer position only where needed (in the bending area) without affecting the overall structural strength provided by the high Young's modulus substrate elsewhere.
Solution Approach 2:
The patent uses composite materials by combining the high Young's modulus flexible substrate with a buffer layer having different mechanical properties (lower Young's modulus). This composite structure creates a gradient in stiffness that positions the neutral layer within the signal wiring layer in the bending region, protecting circuits while maintaining overall structural integrity.
2Area of stationary object
If the bending radius is reduced for narrow bezel design, then display area is improved, but stress concentration increases causing signal wiring breakage
Solution Approach 1:
The buffer layer with patterned holes is applied specifically in the bending region to locally reduce stiffness and redistribute stress. This allows the bending area to accommodate smaller radii without concentrating excessive stress on the signal wiring, enabling narrow bezel designs while protecting circuit reliability.
Solution Approach 2:
The buffer layer acts as a pre-designed stress cushioning structure that absorbs and distributes bending stresses before they reach the signal wiring layer. By positioning the neutral layer within the signal wiring layer through this buffer structure, the patent protects the circuits from stress damage that would otherwise occur during bending operations.
3Strength
If the neutral layer is positioned below the signal wiring layer, then substrate strength is improved, but signal wiring becomes susceptible to stress damage during bending
Solution Approach 1:
The patent maintains the neutral layer below the signal wiring layer in non-bending areas to preserve substrate strength, while introducing a buffer layer with patterned holes specifically in the bending region. This local modification repositions the neutral layer within the signal wiring layer only where bending occurs, reducing stress on the signal wiring without compromising overall substrate strength.
Solution Approach 2:
The patent changes the mechanical parameters (Young's modulus distribution) of the substrate by introducing the buffer layer with patterned holes. This parameter change locally adjusts the neutral layer position from below the signal wiring layer to within it, reducing stress concentration on the signal wiring during bending while maintaining the original strong substrate structure elsewhere.
Data Source
AI summary
The invention provides an OLED display panel and a method for manufacturing the same. The OLED display panel includes a flexible substrate. The surface of the flexible substrate defines a display area, a bending area, and a binding area. A signal wiring layer is provided in the bending area. A buffer layer comprising patterned holes is provided on the flexible substrate corresponding to the bending area, and the neutral layer of the bending area is adjusted into the signal wiring layer to prevent the signal wiring from being broken and improve the anti-bending performance.