Aluminosilicate Glass Composition for Touch Screens
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Solution Overview
Problem
Current glass materials for touch screens lack sufficient scratch resistance and transmissivity, and chemical strengthening methods often require high salt bath temperatures or long treatment times, which can weaken the glass network, while also posing environmental concerns and requiring complex antibacterial processes.
Innovation Solution
An aluminosilicate glass composition with specific chemical formulations and a low-temperature ion-exchange process in a 100% KNO3 salt bath, optimized for temperature and time, to achieve high strength, scratch resistance, and antibacterial properties without using environmentally harmful substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high salt bath temperature or long treatment time is used for chemical strengthening, then glass strength is improved, but glass network is weakened and environmental harm increases
Solution Approach 1:
The patent changes the chemical composition parameters of the glass, specifically incorporating Al2O3 (15-25 wt%) and SnO2 (0.1-2 wt%) to modify the glass network structure. This compositional parameter change enables the glass to achieve high strength through low-temperature ion exchange (300-450°C) without requiring harsh strengthening conditions, thus preventing glass network weakening and reducing environmental harm.
2Illumination intensity
If glass thickness is reduced for touch screen application, then transmissivity is improved, but mechanical strength decreases
Solution Approach 1:
The patent creates a composite structure through ion exchange, forming a strengthened surface layer with compressive stress (500-1000 MPa) and a core layer. This composite-like structure allows thin glass (0.3-1.5 mm) to maintain high transmissivity while the surface compressive stress layer provides enhanced mechanical strength and scratch resistance.
Solution Approach 2:
The patent modifies the glass compositional parameters (Al2O3, SnO2, Na2O, K2O ratios) to enable effective low-temperature chemical strengthening. This allows thin glass to achieve sufficient mechanical strength through ion exchange without requiring increased thickness, thereby maintaining high transmissivity.
3Ease of manufacture
If conventional glass composition is used, then manufacturing is simplified, but scratch resistance and transmissivity are insufficient
Solution Approach 1:
The patent optimizes specific compositional parameters: Al2O3 (15-25 wt%) for strength and scratch resistance, SnO2 (0.1-2 wt%) for nucleation and crystal growth control, and controlled amounts of Na2O (8-15 wt%) and K2O (3-8 wt%) for ion exchange capability. These parameter changes enhance scratch resistance and transmissivity while maintaining manufacturability through standard glass melting and floating processes.
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 aluminosilicate glass exhibits enhanced mechanical strength, scratch resistance, and impact resistance, with a compressive stress of 600-1000 MPa and a depth of ion exchange layer of 10-80 μm, while maintaining transmissivity and incorporating an antibacterial function through silver nitrate addition during chemical strengthening.
Implementation Method 1
chemical strengthening process... low-temperature ion-exchange process in a 100% KNO3 salt bath... compressive stress of 600-1000 MPa and a depth of ion exchange layer of 10-80 μm
Data Source
AI summary
An aluminosilicate glass for touch screens is provided. The glass includes, calculated based on weight percentage: SiO2, 55 to 65%; Na2O, 12 to 17%; Al2O3, 15 to 20%; K2O, 2 to 6%; MgO, 3.9 to 10%; ZrO2, 0 to 5%; ZnO, 0 to 4%; CaO, 0 to 4%; Na2O+K2O+MgO+ZnO+CaO, 15 to 28%; SnO2, 0 to 1%; TiO2+CeO2, ≦1%. A chemical strengthening method for glass also provided that includes ion exchange strengthening in a 100% KNO3 salt bath, wherein a preheating temperature ranges from 370° C. to 430° C. and the treatment time is from 0.5 to 16 hours.