Lithium Disilicate Glass-Ceramic Composition for Strength and Transparency
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Solution Overview
Problem
Existing glass-ceramics struggle to achieve the necessary mechanical properties and optical transparency required for high-strength applications, particularly in portable electronic devices.
Innovation Solution
Development of glass-ceramics with a phase assemblage comprising lithium disilicate (Li2Si2O5) as the primary crystalline phase and a residual amorphous glass phase, with specific compositional ratios and properties such as Al2O3 to Li2O ratios, transmittance, and crystallite sizes, enhancing mechanical strength and optical clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If glass-ceramics are used to improve mechanical strength, then strength is improved, but optical transparency deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the Al2O3 to Li2O ratio (greater than or equal to 0 and less than 0.50) and CaO content (greater than 0 wt% to less than 8 wt%) in the glass-ceramic composition. These compositional parameters are optimized to achieve the desired balance between mechanical strength and optical transparency, with transmittance greater than 88% in the 400-750 nm wavelength range.
Solution Approach 2:
The patent utilizes composite materials by creating a glass-ceramic with a specific phase assemblage comprising lithium disilicate (Li2Si2O5) as the primary crystalline phase and a residual amorphous glass phase. This composite structure combines the mechanical strength benefits of crystalline phases with the optical transparency of the glass matrix, resolving the contradiction between strength and transparency.
2Strength
If glass-ceramics are used to improve mechanical properties, then fracture toughness is improved, but manufacturing complexity increases
Solution Approach 1:
The patent simplifies manufacturing by establishing specific parameter ranges for the glass composition, including Al2O3 to Li2O ratio (greater than or equal to 0 and less than 0.50), CaO content (greater than 0 wt% to less than 8 wt%), and ratios of Li2O to ZrO2 (greater than or equal to 1.10 and less than or equal to 5.0). These defined parameters provide a clear manufacturing guideline that reduces complexity while ensuring the desired fracture toughness is achieved.
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 resulting glass-ceramics exhibit improved mechanical properties, including high Young's modulus, fracture toughness, and optical transparency, suitable for use in electronic device covers.
Implementation Method 1
the glass-ceramic has a transmittance of greater than 88% for wavelengths of light within a range from greater than or equal to 400 nm to less than or equal to 750 nm
Data Source
AI summary
A glass-ceramic may comprise a phase assemblage comprising lithium disilicate (Li2Si2O5) as the primary crystalline phase and a residual amorphous glass phase. The glass-ceramic may further comprise greater than or equal to 0 wt % to less than 8 wt % CaO. A ratio of Al2O3 (wt %) to Li2O (wt %) in the glass-ceramic may be greater than or equal to 0 and less than 0.50. The glass-ceramic may have a transmittance of greater than 88% for wavelengths of light within a range from greater than or equal to 400 nm to less than or equal to 750 nm.