Crystallized Glass Strength Transparency Balance
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Solution Overview
Problem
Existing glass ceramics that can be chemically strengthened often fall short in achieving both high drop strength and transparency.
Innovation Solution
A glass ceramic composition that includes specific crystal phases such as lithium disilicate, virgilite, and β-spodumene, along with a residual glass phase, which provides a fracture toughness value of 1.0 MPa·m0.5⁻ or more and a haze value of 0.8% or less for improved strength and transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If glass ceramic is used to improve strength and scratch resistance, then hardness and strength are improved, but transparency deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the crystal phase composition (lithium disilicate 30-65 wt%, β-spodumene 20-60 wt%), crystal size (0.1-10 μm), and residual glass phase content to achieve optimal balance between strength and transparency. By adjusting these parameters within specific ranges, the glass ceramic achieves both high drop strength and high transparency.
Solution Approach 2:
The patent uses composite materials by creating a multi-phase glass ceramic system containing lithium disilicate crystals, β-spodumene crystals, and residual glass phase. This composite structure combines the strength benefits of crystalline phases with the transparency advantages of the glass matrix, achieving superior optical and mechanical properties.
2Strength
If glass ceramic with high crystal content is used to improve strength, then strength is improved, but haze increases and transparency deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the total crystal content (5-90 wt%), individual crystal phase compositions, and crystal size distribution (0.1-10 μm). By optimizing these parameters, the patent achieves high strength through chemical strengthening while maintaining low haze values, resolving the contradiction between strength and transparency.
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 proposed glass ceramic exhibits excellent strength by chemical strengthening and maintains high transparency, effectively addressing the limitations of previous glass ceramics.
Implementation Method 1
a chemically strengthened glass is a glass obtained by immersing a glass in a molten salt such as sodium nitrate to cause ion exchange between an alkali ion contained in the glass and an alkali ion contained in the molten salt and having a larger ion radius, and thereby forming a compressive stress layer on a surface portion of the glass
Implementation Method 2
A glass ceramic is obtained by precipitating a crystal in the glass
Data Source
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AI summary
The present invention provides crystallized glass that achieves excellent strength by chemical toughening, and that is excellent in both strength when dropped and transparency. The present invention relates to crystallized glass that comprises a lithium disilicate type crystal and/or a solid solution crystal thereof, a virgilite type crystal and/or a solid solution crystal thereof, and a residual glass phase, and that has a fracture toughness value KIC of not less than 1.0 MPa·m0.5 and a haze value of not more than 0.8% based on a thickness of 0.7 mm.