Chemically Tempered Glass Composition for Display Covers
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Solution Overview
Problem
Existing chemically tempered glasses used as cover materials for electronic components and displays are difficult to process due to their viscosity properties, making them challenging to fuse, refine, and hot-form, while also being prone to crystallization.
Innovation Solution
A chemically temperable glass composition comprising SiO2, Al2O3, Li2O, and B2O3, with specific ratios of these constituents, is developed. This glass is produced through a melting process, refining, and hot forming, followed by an ion exchange process in a bath with varying compositions of KNO3, NaNO3, and LiNO3 at controlled temperatures and durations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If LABS glasses with high Li2O proportion are used to achieve good chemical temperability and mechanical strength, then the glass exhibits high strength against sharp and blunt impact stresses, but the glass becomes difficult to process during melting, refining, and hot forming due to unfavorable viscosity properties
Solution Approach 1:
The patent applies parameter changes by precisely controlling the Li2O content within a specific range (4-12 mol%) rather than using high Li2O proportions. It also adjusts the B2O3 content (0.1-8.5 mol%) and maintains specific ratios between components (Al2O3/(Li2O+Na2O+K2O) = 0.5-1.5, B2O3/(Li2O+Na2O+K2O) = 0.05-0.8) to optimize both chemical temperability and processing characteristics, resolving the contradiction between strength and manufacturability
Solution Approach 2:
The patent creates a composite glass system combining SiO2, Al2O3, Li2O, B2O3, and optional additives (Na2O, K2O, MgO, CaO, SrO, BaO, ZnO) in specific proportions. This composite composition leverages the complementary properties of each component: SiO2 provides network stability, Al2O3 enhances strength, Li2O enables chemical tempering, and B2O3 improves processability, achieving both high mechanical strength and ease of manufacture
2Strength
If glasses with high alkali metal oxide content are used to improve chemical temperability, then ion exchange efficiency increases, but the glass becomes more susceptible to crystallization during production
Solution Approach 1:
The patent controls the total alkali metal oxide content (Li2O+Na2O+K2O) within a specific range and maintains the ratio Al2O3/(Li2O+Na2O+K2O) = 0.5-1.5 to balance chemical temperability and crystallization resistance. By adjusting these parameters, the glass achieves good ion exchange efficiency while maintaining stability during production processes
Solution Approach 2:
The glass composition combines alkali metal oxides (Li2O, Na2O, K2O) with Al2O3 and B2O3 in specific proportions to create a composite system where Al2O3 and B2O3 act as stabilizers that prevent crystallization while allowing sufficient alkali content for effective chemical tempering
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 is easily fusible, refinable, and hot-formable, with improved mechanical strength and resistance to crystallization, making it suitable for use as a cover in electronic devices without the challenges of processing and crystallization associated with previous glasses.
Implementation Method 1
LABS glasses have the advantage that they are very readily chemically temperable through ion exchange of Li ions for Na ions or through combined ion exchange, namely Li ions for Na ions and Na ions for K ions
Data Source
AI summary
A chemically temperable or chemically tempered glass includes SiO2, Al2O3, Li2O and B2O3 as constituents. The following applies for the constituents (in mol % based on oxide): 0.8<Li2O/(Li2O+K2O+Na2O)≤1 and 0.1<B2O3≤8.5.