Lithium Aluminosilicate Cover Glass for Thin Drop-Resistant Screens
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cover glasses for electronic devices are vulnerable to flexure and sharp contact failures during accidental drops, and there is a need for glasses that are both strengthened and capable of being formed into thin articles while maintaining mechanical integrity.
Innovation Solution
A lithium-containing aluminosilicate glass composition with specific ranges of SiO2, Al2O3, Li2O, and other oxides, characterized by a compressive stress region and high fracture toughness, enabling efficient production of thin glass articles with enhanced resistance to impact and indentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If ion exchange technique is used to induce compressive stress in glass surface, then resistance to flexure failure is improved, but vulnerability to sharp contact failure remains high due to stress concentration from local indentations
Solution Approach 1:
The patent changes the chemical composition parameters of the glass, specifically using a lithium aluminosilicate composition with controlled ratios of Li2O, Al2O3, and SiO2, which fundamentally alters the glass properties to achieve both flexure and sharp contact resistance without relying solely on ion exchange
Solution Approach 2:
The patent creates a composite glass system combining multiple oxides (lithium oxide, aluminum oxide, silicon dioxide, and other metal oxides) in specific proportions to achieve synergistic effects that simultaneously improve both flexure strength and sharp contact resistance
2Strength
If glass composition is optimized for strength through ion exchange, then fracture toughness improves, but manufacturability and ability to form thin articles deteriorates
Solution Approach 1:
The patent optimizes the chemical composition parameters to balance strength and manufacturability, using specific ranges of oxide concentrations that enable both high fracture toughness and good formability for thin glass articles
Solution Approach 2:
The patent creates different properties in different regions of the glass structure through controlled composition, where the surface region provides high strength while the bulk composition maintains good manufacturability and formability
3Length of moving object
If cover glass thickness is reduced to make devices thinner, then device thickness is improved, but damage resistance deteriorates
Solution Approach 1:
The patent changes the material properties through composition optimization, enabling thin glass articles to achieve high damage resistance that would normally require much thicker glass
Solution Approach 2:
The patent successfully creates thin glass films and sheets with enhanced strength properties, allowing cover glasses to be both thin and highly damage-resistant through the specialized lithium aluminosilicate composition
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 glass composition achieves high fracture toughness and compressive stress, providing improved resistance to flexure and sharp contact failures, while allowing for efficient manufacturing processes.
Implementation Method 1
The glass composition undergoes ion exchange to create a compressive stress region, enhancing fracture toughness and allowing for thin, durable glass articles
Data Source
AI summary
A glass composition includes: 50 mol % to 69 mol % SiO2; 12.5 mol % to 25 mol % Al2O3; 0 mol % to 8 mol % B2O3; greater than 0 mol % to 4 mol % CaO; greater than 0 mol % to 17.5 mol % MgO; 0.5 mol % to 8 mol % Na2O; 0 mol % to 2.5 mol % La2O3; and greater than 8 mol % to 18 mol % Li2O, wherein (Li2O+Na2O+MgO)/Al2O3 is from 0.9 to less than 1.3; and Al2O3+MgO+Li2O+ZrO2+La2O3+Y2O3 is from greater than 23 mol % to less than 50 mol %. The glass composition may be characterized by at least one of the following: a K1C value measured by a chevron short bar method of at least 0.75; and a K1C value measured by a double torsion method of at least 0.8. The glass composition is chemically strengthenable. The glass composition may be used in a glass article or a consumer electronic product.