Thin Glass Composition for Foldable Displays
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Solution Overview
Problem
Conventional glass articles used in portable electronic devices, such as smartphones and tablets, face challenges in balancing thinness for portability with the need to withstand external impacts and flexibility for foldable display devices, as they often lack sufficient mechanical strength and impact resistance.
Innovation Solution
A glass composition with a novel composition ratio of 59 to 69 mol% SiO2, 8 to 18 mol% Al2O3, 0 to 5 mol% Na2O, 0 to 5 mol% ZnO, 0 to 10 mol% B2O3, and 10 to 20 mol% CaO or 15 to 25 mol% MgO, which satisfies the condition 4.5≤Al2O3/Na2O≤5.5, is developed, resulting in a glass article with enhanced mechanical strength, surface strength, and impact resistance while maintaining flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the glass article is made thinner to improve portability, then the weight and size are reduced, but the mechanical strength and impact resistance deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the glass, specifically setting Al2O3 content to 12-18 mol%, Na2O to 1.5-4.0 mol%, and controlling the Al2O3/Na2O ratio to 3.0-6.0, which improves mechanical strength while maintaining thinness
Solution Approach 2:
The patent creates a composite glass material combining multiple oxides (SiO2, Al2O3, Na2O, B2O3, CaO, MgO, ZnO) in specific proportions to achieve both thinness and high strength, with the glass article having thickness of 100 μm or less while maintaining fracture toughness of 0.95 MPa·m^0.5 or more
2Adaptability or versatility
If the glass article is made thinner to improve flexibility for foldable devices, then the bending stress is reduced, but the impact resistance deteriorates
Solution Approach 1:
The patent adjusts glass composition parameters including B2O3 (3-10 mol%) to control flexibility and CaO (5-15 mol%) or MgO (10-25 mol%) to enhance impact resistance, achieving both foldability and durability
Solution Approach 2:
The patent applies different properties to different aspects of the glass: the bulk composition provides flexibility for folding while the surface composition and overall structure provide impact resistance, with surface strength of 900 MPa or more
3Strength
If the Al2O3 content is increased to improve mechanical strength, then the strength increases, but the manufacturing complexity increases
Solution Approach 1:
The patent optimizes the Al2O3 content to a specific range (12-18 mol%) and controls the Al2O3/Na2O ratio (3.0-6.0) to achieve high strength while maintaining manufacturability, avoiding excessive complexity
Solution Approach 2:
The patent incorporates B2O3 (3-10 mol%) which can form a glass structure with appropriate porosity and flexibility, reducing the need for excessive Al2O3 while maintaining strength properties
Data Source
AI summary
A glass composition, a glass article prepared therefrom, and a display device are provided. The glass article includes as a glass composition: 59 to 69 mol % of SiO2, 8 to 18 mol % of Al2O3, greater than 0 to 5 mol % of Na2O, greater than 0 to 5 mol % of ZnO, and greater than 0 to 10 mol % of B2O3, and glass article further includes 10 to 20 mol % of CaO or 15 to 25 mol % of MgO, satisfies Relation 1 below, and has a thickness of 100 μm or less,4.5≤Al2O3/Na2O≤5.5 (Relation 1),where, in Relation 1, Al2O3 and Na2O represent contents (mol %) of corresponding components, respectively, in the glass composition.