Glass-Ceramic Cover Composition for Drop and Scratch Resistance
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Solution Overview
Problem
Existing protective glass for electronic devices, such as aluminosilicate glass, lacks both sufficient drop resistance and scratch resistance, leading to high screen breakage rates and poor user experience.
Innovation Solution
A glass-ceramic composition with specific crystalline phases, including spinel and ZrO2, and controlled molar ratios of Li2O, Na2O, K2O, SiO2, Al2O3, MgO, and ZnO, which enhances both drop resistance and scratch resistance through ion exchange and crystalline phase distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If common aluminosilicate glass is used for protective glass, then the glass can be manufactured with current technology, but the glass has poor drop resistance and low intrinsic structure strength
Solution Approach 1:
The patent changes the chemical composition parameters by introducing specific ratios of Li2O, Na2O, and K2O (0.11≤(Li2O+Na2O+K2O)/(SiO2+Al2O3)≤0.30) and controlling Na2O/(MgO+ZnO)≤0.9, which fundamentally alters the glass structure to enable simultaneous improvement in intrinsic strength and drop resistance through ion exchange mechanisms
Solution Approach 2:
The patent creates a composite glass-ceramic material containing spinel crystalline phase and ZrO2 crystalline phase dispersed in a glass matrix, combining the benefits of glass processing with the mechanical strength and toughness of crystalline phases to achieve both drop resistance and scratch resistance
2Strength
If common aluminosilicate glass is used for protective glass, then the glass can be chemically strengthened, but the glass still has poor drop resistance and low intrinsic hardness
Solution Approach 1:
The patent optimizes the Na2O content relative to MgO and ZnO (Na2O/(MgO+ZnO)≤0.9) to balance ion exchange capability for surface hardening with the formation of high-hardness spinel crystalline phase, achieving both high intrinsic hardness and excellent scratch resistance that cannot be achieved with conventional aluminosilicate glass
Solution Approach 2:
The spinel crystalline phase (MgAl2O4, ZnAl2O4, or (Mg,Zn)Al2O4) with inherent high hardness (Mohs hardness 8-9) is formed within the glass matrix, providing intrinsic scratch resistance that supplements the chemically strengthened surface, creating a multi-layered defense against scratching
3Reliability
If the ratio (Li2O+Na2O+K2O)/(SiO2+Al2O3) is increased to improve ion exchange capability, then the glass has better chemical strengthening performance, but the glass may have reduced structural stability
Solution Approach 1:
The patent precisely defines the optimal range 0.11≤(Li2O+Na2O+K2O)/(SiO2+Al2O3)≤0.30, which provides sufficient alkali oxides for ion exchange while maintaining adequate SiO2 and Al2O3 to preserve the glass network structure and crystalline phase stability, achieving a balanced composition that satisfies both requirements
Solution Approach 2:
The patent creates different functional zones: the surface region undergoes ion exchange to form a compressed stress layer for strength enhancement, while the bulk region maintains the designed composition to ensure structural stability and controlled crystallization of spinel and ZrO2 phases, achieving local optimization of different properties
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 exhibits improved mechanical strength, scratch resistance, and optical properties, making it suitable for protective covers in electronic devices with reduced breakage and scratching.
Implementation Method 1
A ratio in molar percentages, that is, (Li2O+Na2O+K2O)/(SiO2+Al2O3) is controlled to range from 0.11 to 0.30, and Na2O/(MgO+ZnO) is controlled to be less than or equal to 0.9, so that the glass-ceramic can have both excellent drop resistance and scratch resistance.
Implementation Method 2
sequentially performing nucleation treatment and crystallization treatment on the glass base material, so that the glass base material is crystallized to obtain a glass-ceramic material, where crystalline phases in the glass-ceramic are a spinel crystalline phase and a ZrO2 crystalline phase
Implementation Method 3
sequentially performing nucleation treatment and crystallization treatment on the glass base material, so that the glass base material is crystallized to obtain a glass-ceramic material, where crystalline phases in the glass-ceramic are a spinel crystalline phase and a ZrO2 crystalline phase
Data Source
Figure 1~2
Figure 3~5
AI summary
Embodiments of this application provide glass-ceramic and a preparation method therefor, a glass cover, and an electronic device. Crystalline phases in the glass-ceramic are a spinel crystalline phase and a ZrO2 crystalline phase. The glass-ceramic includes SiO2, Al2O3, MgO, ZnO, ZrO2, Na2O, Li2O with a molar percentage of 0% to 9%, and K2O with a molar percentage of 0% to 5%; and molar percentages of components satisfy: 0.11≤(Li2O+Na2O+K2O)/(SiO2+Al2O3)≤0.30, and Na2O/(MgO+ZnO)≤0.9. The glass-ceramic has good drop resistance and scratch resistance, and can better meet an application requirement in the field of electronic devices and the like.