Display Panel Bending Groove Structure for Narrow-Bezel Reliability
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Solution Overview
Problem
The advancement of narrow-frame display panels is limited by the risk of metal wiring breakage due to high bending stress in the bending area, which restricts the reduction of the lower frame width, especially in mobile phone displays.
Innovation Solution
A display panel design featuring a substrate layer with a groove on its surface away from the metal wiring layer, where the groove wall transitions smoothly to the groove bottom, reducing bending stress and preventing stress concentration, and a support layer with a cavity to further alleviate stress, allowing for a smaller bending radius and improved bending yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the bending radius of the bending area is reduced to achieve narrower lower frame width, then the width of the lower frame is reduced, but the bending stress on the metal wiring layer increases and the risk of metal wiring breakage increases
Solution Approach 1:
The substrate layer is designed with a groove structure that creates a localized thinning or porous region. This groove reduces the substrate thickness in the bending area, thereby reducing the overall bending stress on the metal wiring layer while maintaining structural integrity in non-bending areas. The groove acts as a stress-relief feature that allows controlled deformation without causing wiring breakage.
Solution Approach 2:
The invention introduces a vertical dimension feature (the groove depth) to solve a horizontal problem (bending stress). By creating a groove that extends into the substrate thickness direction, the patent adds a third dimension to the stress distribution, allowing stress to be relieved through the depth of the groove rather than just along the bending radius.
2Length of moving object
If the bending radius is reduced further, then the narrow-frame design is achieved, but the bending yield of the display panel decreases due to metal wiring breakage
Solution Approach 1:
The groove structure creates a controlled porous or thinned region in the substrate that reduces stress concentration during bending. This allows the metal wiring layer to bend without experiencing excessive stress that would cause breakage, thereby improving bending yield while maintaining small bending radius.
Solution Approach 2:
The groove is pre-formed in the substrate layer before the bending process. This beforehand structural modification acts as a cushion or stress-absorbing feature that prevents excessive stress from reaching the metal wiring layer during subsequent bending operations, thereby protecting against wiring breakage and improving reliability.
Data Source
AI summary
A display panel and a manufacturing method thereof are provided. The display panel includes a non-display area which is provided with a bending area. The bending area includes a substrate layer, a metal wiring layer, and a first planarization layer sequentially disposed. A groove is defined on a surface of the substrate layer away from the metal wiring layer, where a groove wall of the groove extends along a curved surface or a flat surface to a groove bottom of the groove to let an orthographic projection of the groove bottom of the groove on the substrate layer fall within an orthographic projection of an opening of the groove on the substrate layer, so that the metal wiring layer is located in a neutral layer or close to the neutral layer.