Tapered Foldable Glass Substrate for Bending Strength and Impact Durability
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Solution Overview
Problem
Conventional foldable glass substrates lack sufficient durability and bending strength, making them prone to damage when used in foldable display devices, which require robustness against impacts and flexible operation modes.
Innovation Solution
A foldable glass substrate design featuring a top surface, bottom surface, and side surfaces with specific angle configurations and dimensions, including a reinforced area with higher compressive stress and a non-reinforced area, optimized through etching and chemical strengthening processes to enhance bending strength and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional glass substrate design is used, then manufacturing simplicity is maintained, but bending strength and durability are insufficient
Solution Approach 1:
The glass substrate employs an asymmetric cross-sectional structure with a C-shaped or tapered profile, where the side surfaces have different lengths and angles. Specifically, the first side surface extends at a first angle from the top surface, the second side surface extends at a second angle from the bottom surface, and the third side surface connects them, creating an asymmetric geometry that enhances bending strength by distributing stress more effectively during folding operations.
Solution Approach 2:
The invention optimizes specific geometric parameters of the glass substrate, including the angles of the side surfaces (first angle and second angle), the length of the third side surface (equal to or greater than 0.3 times and equal to or less than 0.7 times the minimum thickness), and the thickness range (15-100 μm). These parameter changes are designed to maximize bending strength while maintaining manufacturability.
2Reliability
If glass substrate thickness is increased, then durability against impact is improved, but flexibility and foldability are reduced
Solution Approach 1:
The invention identifies an optimal thickness range of 15-100 μm for the glass substrate, balancing durability and foldability. Within this range, the substrate is thick enough to resist impacts and maintain structural integrity, yet thin enough to enable flexible folding operations without excessive rigidity that would prevent bending.
Solution Approach 2:
The asymmetric C-shaped or tapered cross-sectional structure distributes mechanical stresses more effectively during folding, allowing the substrate to maintain durability at reduced thickness levels. The varying side surface lengths and angles create a structure that is stronger at critical stress points while remaining flexible overall.
3Strength
If side surface length is increased, then bending strength is improved, but resistance to lateral impact is reduced
Solution Approach 1:
The invention optimizes the length of the third side surface to be equal to or greater than 0.3 times and equal to or less than 0.7 times the minimum thickness of the glass substrate. This specific parameter range ensures sufficient bending strength while maintaining adequate lateral impact resistance by preventing the side surface from being excessively long, which would create leverage points vulnerable to lateral forces.
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 optimized glass substrate achieves a substantial increase in bending strength and durability, enabling it to withstand impacts and maintain flexibility, thus improving the performance of foldable display devices.
Implementation Method 1
the reinforced area may include a first alkali metal cation. the non-reinforced area may include a second alkali metal cation having an ion radius less than that of the first alkali metal cation
Implementation Method 2
the reinforced area may include a first alkali metal cation. the non-reinforced area may include a second alkali metal cation having an ion radius less than that of the first alkali metal cation
Data Source
AI summary
A foldable glass substrate includes a top surface, a bottom surface, and a side surface. The side surface includes a first side surface extending at a first angle from the top surface, a second side surface extending at a second angle from the bottom surface, and a third side surface extending from each of the first side surface and the second side surface. A length of the third side surface in a direction substantially perpendicular to at least one of the top surface and the bottom surface is equal to or greater than about 0.3 times and equal to or less than about 0.7 times of a minimum distance between the top surface and the bottom surface. The minimum distance is equal to or greater than about 15 micrometers (μm) and equal to or less than about 100 μm.