Glass-Ceramic Composition With Compressive Layer for Crack Resistance
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Solution Overview
Problem
Existing glass and ceramic materials fail to provide resistance to crack penetration and drop performance, and there is a need to improve the mechanical properties such as resistance to crack penetration and drop performance in glass-ceramic articles used as cover substrates and housings for mobile electronic devices.
Innovation Solution
The development of glass-ceramic articles with tailored crystalline phases, residual glass phases, and controlled compressive stress layers, combined with ion exchange processes, to enhance fracture toughness, stored tensile energy, and optical characteristics, such as high fracture toughness, stored tensile energy, and low haze.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional glass-ceramic articles are used, then manufacturing is simpler, but resistance to crack penetration and drop performance are insufficient
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters (adding specific oxides like Al2O3, B2O3, SiO2 within defined ranges) and heat treatment parameters (nucleation temperature TN=500-650°C, crystallization temperature TC=680-800°C, hold times tN and tC) to achieve superior crack resistance and drop performance while maintaining manufacturability
Solution Approach 2:
The patent creates a composite glass-ceramic material system combining multiple oxide components (SiO2, Al2O3, B2O3, Li2O, P2O5, ZrO2) with controlled phase assemblage including crystalline phases and residual glass phase, resulting in enhanced mechanical properties including resistance to crack penetration and drop performance
2Strength
If conventional glass-ceramic articles are used, then manufacturing is simpler, but drop performance is insufficient
Solution Approach 1:
The patent modifies material parameters including oxide composition ratios (Li2O: 20-32 mol%, Al2O3: 1-6 mol%, B2O3: 0.1-2 mol%, P2O5: 0.5-2 mol%, ZrO2: 1.7-4.5 mol%) and heat treatment parameters to achieve high drop performance while maintaining reasonable manufacturing complexity
Solution Approach 2:
The patent develops a composite glass-ceramic material with specific phase assemblage containing crystalline phases (lithium disilicate, petalite, β-spodumene) and residual glass phase, providing enhanced toughness and drop performance through the synergistic combination of crystalline and glassy phases
3Illumination intensity
If heating treatments are applied to achieve transparency, then optical characteristics improve, but haze increases
Solution Approach 1:
The patent optimizes heating treatment parameters including nucleation temperature (TN=500-650°C), nucleation hold time (tN=1-12 hours), crystallization temperature (TC=680-800°C), and crystallization hold time (tC=0.5-10 hours) to control crystal grain size and distribution, achieving high transparency with low haze (<0.2)
Solution Approach 2:
The patent achieves local quality control by creating a uniform fine-grained microstructure throughout the glass-ceramic article through controlled nucleation and crystallization, ensuring consistent optical properties including high transparency and low haze across the entire material
4Strength
If fracture toughness is increased, then resistance to crack penetration improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific parameter ranges for heating treatment (TN=500-650°C, tN=1-12 h, TC=680-800°C, tC=0.5-10 h) that provide a robust process window achieving fracture toughness >1.0 MPa√m without requiring extreme manufacturing precision, as the ranges accommodate normal process variations
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 articles exhibit improved mechanical properties, including fracture toughness greater than 1.0 MPa√m, stored tensile energy greater than 22 J/m2, and haze less than 0.2, while maintaining transparency, enhancing resistance to crack penetration and drop performance.
Implementation Method 1
heating a glass composition to a nucleation temperature to create a nucleated crystallizable glass composition
Implementation Method 2
heating the nucleated crystallizable glass composition to a crystallization temperature and maintaining the crystallization temperature for a predetermined period of time to produce the glass-ceramic article
Implementation Method 3
ion-exchanged glass-ceramic articles with high fracture toughness and stored tensile energy
Data Source
AI summary
A glass-ceramic article having one or more crystalline phases; a residual glass phase; a compressive stress layer extending from a first surface to a depth of compression (DOC); a maximum central tension greater than 70 MPa; a stored tensile energy greater than 22 J/m2; a fracture toughness greater than 1.0 MPa√m; and a haze less than 0.2.