Glass-Ceramic Clad Layers for Laminated Glass Strength
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Solution Overview
Problem
Glass articles in electronic devices require enhanced strength to withstand regular contact and incidental impacts, but existing glass compositions face challenges in balancing strength with formability and thermal expansion characteristics, particularly in laminated glass applications where compressive stress development complicates singulation and strengthening processes.
Innovation Solution
A glass-ceramic composition with specific mole percentages of SiO2, Al2O3, alkali oxide (Li2O and Na2O), and alkaline earth oxide (MgO) is developed, featuring a major crystalline phase of Li2Si2O5, which allows for controlled compressive stress introduction through thermal expansion mismatch between core and clad layers, enabling robust and formable glass-ceramic clad layers for laminated glass articles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If glass articles use enhanced strength compositions to withstand contact and impacts, then strength and durability are improved, but formability and thermal expansion characteristics deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the chemical composition ratios of SiO2 (60-75 mol%), Al2O3 (5-10 mol%), alkali oxides (2-20 mol%), and alkaline earth oxides (0-5 mol%). This specific parameter range enables the glass to achieve enhanced strength while maintaining formability, resolving the contradiction between these two properties.
Solution Approach 2:
The patent creates a composite glass-ceramic material that combines multiple oxide components in specific proportions. This composite structure allows the material to simultaneously exhibit high strength from the glass matrix and controlled thermal expansion from the crystalline phases, while preserving formability during manufacturing processes.
2Strength
If compressive stress is introduced through thermal expansion mismatch in laminated glass, then strength is improved, but singulation and strengthening processes become more complex
Solution Approach 1:
The patent utilizes thermal expansion mismatch between the glass core layer and glass-ceramic clad layers to generate compressive stress in the clad layers. By controlling the CTE of each layer, the patent achieves strength enhancement through this built-in stress, while the specific composition ranges ensure that the thermal expansion differences are predictable and manageable, preventing excessive process complexity.
3Stability of the object's composition
If glass-ceramic composition uses specific oxide ratios for controlled thermal expansion, then thermal expansion characteristics are improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific parameter ranges for each oxide component (SiO2: 60-75 mol%, Al2O3: 5-10 mol%, alkali oxides: 2-20 mol%, alkaline earth oxides: 0-5 mol%) that ensure stable thermal expansion characteristics. These parameter specifications provide manufacturing guidance that balances composition control precision with achievable manufacturing capabilities, resolving the contradiction between stability and precision requirements.
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-ceramic composition provides enhanced strength and formability, allowing for controlled compressive stress development in clad layers, facilitating easier singulation and strengthening of laminated glass articles while maintaining suitable thermal expansion properties for electronic device applications.
Implementation Method 1
controlled compressive stress introduction through thermal expansion mismatch between core and clad layers
Implementation Method 2
A major crystalline phase of the glass-ceramic composition may be Li2Si2O5
Data Source
AI summary
According to one embodiment, a glass-ceramic composition may include from about 60 mol. % to about 75 mol. % SiO2; from about 5 mol. % to about 10 mol. % Al2O3; from about 2 mol. % to about 20 mol. % alkali oxide R2O, the alkali oxide R2O including Li2O and Na2O; and from 0 mol. % to about 5 mol. % alkaline earth oxide RO, the alkaline earth oxide RO including MgO. A ratio of Al2O3 (mol. %) to the sum of (R2O (mol. %)+RO (mol. %)) may be less than 1 in the glass-ceramic composition. A major crystalline phase of the glass-ceramic composition may be Li2Si2O5. A liquidus viscosity of the glass-ceramic composition may be greater than 35 kP. The glass-ceramic composition may be used to form the glass clad layer(s) of a laminated glass article.