Foldable Display Substrate With Segmented Stress Relief Grooves
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Solution Overview
Problem
The existing substrates for flexible or foldable display devices suffer from random waveness on their surfaces due to the cold rolling process, leading to deformation and reliability issues during repeated folding and unfolding operations.
Innovation Solution
A substrate for display is designed with a specific structure that includes a first area for folding and a second area for unfolding, featuring a combination of through-holes and grooves on both surfaces to control stress distribution and waveness, thereby enhancing the substrate's strength, elasticity, and heat dissipation characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal substrate undergoes cold rolling process before pattern formation, then the substrate achieves necessary strength and structural integrity, but random waveness is formed on the surface causing deformation and reliability issues
Solution Approach 1:
The substrate is divided into multiple regions with different pattern densities. The first region has a higher density of stress relief patterns than the second region, allowing localized control of waveness while maintaining overall structural integrity. This segmentation enables the substrate to achieve both strength and surface flatness by distributing stress relief features non-uniformly across different areas.
Solution Approach 2:
Different regions of the substrate are assigned different pattern densities to address local stress distribution requirements. The first region with higher pattern density addresses areas prone to waveness formation, while the second region with lower density maintains structural strength. This local differentiation resolves the contradiction between achieving surface flatness and maintaining substrate strength.
2Stress or pressure
If stress relief patterns such as holes or grooves are formed in the metal substrate, then stress due to folding is dispersed, but the substrate becomes more complex and may develop cracks during repeated folding operations
Solution Approach 1:
The stress relief patterns are segmented into two distinct regions with different densities. The first region with higher density provides enhanced stress relief in critical areas, while the second region with lower density maintains structural integrity. This segmentation prevents crack propagation while effectively dispersing stress during folding operations.
Solution Approach 2:
Stress relief patterns are pre-formed in the substrate before folding operations to cushion and distribute stress. The non-uniform pattern density is designed in advance to prevent stress concentration at specific locations, thereby preventing crack formation during repeated folding and unfolding cycles.
3Manufacturing precision
If the substrate is designed with higher pattern density to control waveness, then surface deformation is reduced, but the manufacturing complexity increases
Solution Approach 1:
Different regions of the substrate are assigned different pattern densities based on local requirements. The first region with higher pattern density is applied only where waveness control is critical, while the second region with lower density is used where structural strength is the priority. This local differentiation achieves surface flatness without unnecessarily increasing manufacturing complexity across the entire substrate.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed substrate effectively disperses stress during folding, prevents cracks and deformations, and improves the shape-retaining force and rigidity when restored, while also enhancing heat dissipation characteristics, thus improving the overall reliability and performance of flexible or foldable display devices.
Implementation Method 1
a first hole passing through the one surface and the other surface is formed in the first area, a 1-1 groove is formed on the one surface of the first area from the one surface toward the other surface, a 1-2 groove is formed on the other surface of the first area from the other surface toward the one surface
Implementation Method 2
enhancing the substrate's strength, elasticity, and heat dissipation characteristics
Data Source
AI summary
A substrate for display comprises one surface, the other surface, a first area (folding area) and a second area (non-folding area). A first hole passing through the one surface and the other surface is formed on the first area. A 1-1 groove is formed on one surface of the first area in the direction from the one surface to the other surface. A 1-2 groove is formed on the other surface of the first area in the direction from the other surface to the one surface. A 2-1 groove is formed on one surface of the second area in the direction from the one surface to the other surface. A 2-2 groove is formed on the other surface of the second area in the direction from the other surface to the one surface. The 1-1 groove and 1-2 groove and the 2-1 groove and 2-2 groove do not overlap each other in the thickness direction of the substrate for display.