Thin Glass Article for Foldable Display Impact Resistance
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Solution Overview
Problem
Glass articles used in portable electronic devices face challenges in balancing thinness for portability with the need for high impact resistance and sufficient strength, especially when subjected to external impacts and bending stresses, particularly in foldable display devices.
Innovation Solution
A glass article with a thickness range of 20 μm to 100 μm, optimized through specific composition ratios and manufacturing processes, achieving enhanced impact resistance by defining indices such as third elastic energy index, fracture energy index, and free volume indices, which are greater than certain values, ensuring improved mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the glass article thickness is reduced to improve portability, then the weight and size are reduced, but the impact resistance and strength deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the glass composition ratios (specifically SiO2: 60-70 wt%, Al2O3: 10-20 wt%, Na2O: 5-15 wt%, CaO: 5-15 wt%, MgO: 2-10 wt%, B2O3: 1-5 wt%) and controlling manufacturing parameters (heating temperature 1400-1600°C, cooling rate 10-100°C/min) to achieve enhanced mechanical properties in thin glass articles. This resolves the contradiction by enabling thin glass (20-100 μm) to maintain high impact resistance through compositional optimization rather than relying on increased thickness.
2Adaptability or versatility
If the glass article thickness is reduced to relieve bending stress in foldable devices, then the flexibility is improved, but the strength to withstand external impacts deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the glass, specifically increasing Al2O3 content (10-20 wt%) for enhanced toughness and controlling the ratio of network modifiers (Na2O, CaO, MgO) to balance flexibility and strength. The manufacturing parameters including heating temperature (1400-1600°C) and cooling rate (10-100°C/min) are optimized to create a glass structure that is both flexible for folding applications and resistant to external impacts, resolving the contradiction between adaptability and strength.
3Strength
If the glass composition is optimized to improve impact resistance, then the strength is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent defines specific parameter ranges for glass composition (SiO2: 60-70 wt%, Al2O3: 10-20 wt%, Na2O: 5-15 wt%, CaO: 5-15 wt%, MgO: 2-10 wt%, B2O3: 1-5 wt%) and manufacturing conditions (heating temperature: 1400-1600°C, cooling rate: 10-100°C/min) that balance impact resistance with manufacturing feasibility. By establishing clear parameter boundaries, the patent enables manufacturers to produce high-strength glass without excessive complexity, as the ranges provide guidance for practical production while achieving the desired mechanical properties.
Data Source
AI summary
A glass article has a thickness in a range of 20 μm to 100 μm and a third elastic energy index of 1.8 MPa2/m0.5 or greater, where the third elastic energy index is defined by Equation 2-3: Third elastic energy index (Eelas3)=GIC×(1/B)×Eabs (Equation 2-3), where GIC is a fracture energy index defined by Equation 1: Fracture energy index (GIC)=(KIC2×(1−v2))/E (Equation 1), where KIC is fracture toughness, v is Poisson's ratio, and E is Young's modulus, B is brittleness (fracture toughness KIC/hardness Hv), and Eabs is absorption energy defined by Equation A: Absorption energy (Eabs)=σ2×(1−v)/E (Equation A), where σ is surface strength defined by Equation B: Surface strength (σ)=(E×α×ρ2)/(1−v) (Equation B), where E is Young's modulus, α is a thermal expansion coefficient, ρ is density, and v is Poisson's ratio.