Aluminoborosilicate Glass for Bezel-less Mobile Enclosures
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Solution Overview
Problem
Glass enclosures in electronic devices are prone to breakage due to direct impact and scratching, limiting their design to flat pieces and preventing the utilization of glass features like crystal-like appearances, as they lack sufficient crack initiation threshold and scratch resistance.
Innovation Solution
Development of an aluminoborosilicate glass with a composition comprising at least 50 mol % SiO2, 9-17 mol % Al2O3, 2-12 mol % B2O3, 8-16 mol % Na2O, and 0-4 mol % K2O, which is ion exchangeable and exhibits a ratio of Al2O3+B2O3/Σmodifiers >1, providing enhanced scratch resistance and crack initiation threshold through compressive stress and densification upon indentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If glass is used in electronic devices without a bezel, then device complexity is reduced and design freedom is improved, but the glass becomes vulnerable to breakage from direct impact and scratching
Solution Approach 1:
The patent changes the chemical composition parameters of the glass by incorporating specific ratios of Al2O3 (10-20 wt%), B2O3 (5-15 wt%), and SiO2 (60-80 wt%), along with controlled amounts of alkali and alkaline earth metal oxides. This compositional parameter change enables the glass to achieve both bezel-less design compatibility and enhanced durability through improved crack initiation resistance and scratch hardness.
Solution Approach 2:
The patent creates a composite glass material system that combines multiple oxide components (Al2O3, B2O3, SiO2, alkali metal oxides, alkaline earth metal oxides) in specific proportions. This composite material approach allows the glass to simultaneously achieve optical clarity, mechanical strength, and chemical durability without requiring a protective bezel structure.
2Ease of manufacture
If traditional glass composition is used, then manufacturing simplicity is maintained, but scratch resistance and retained strength are insufficient
Solution Approach 1:
The patent modifies the chemical composition parameters by specifying Al2O3 content at 10-20 wt% and B2O3 at 5-15 wt%, which significantly enhances scratch resistance and Vickers hardness. These parameter changes maintain compatibility with standard glass manufacturing processes while achieving superior mechanical properties including improved retained strength after scratching and higher resistance to crack initiation.
3Adaptability or versatility
If glass edges are exposed without bezel protection, then design versatility is improved, but the glass becomes highly susceptible to fragmentation from edge impact
Solution Approach 1:
The patent changes the glass composition parameters to include 10-20 wt% Al2O3 and 5-15 wt% B2O3, which significantly improves edge strength and impact resistance. This enables the glass to be used in bezel-less designs with exposed edges while maintaining high resistance to fragmentation from direct impact and allowing greater design versatility for curved and three-dimensional forms.
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 aluminoborosilicate glass demonstrates improved resistance to scratching and direct impact, retaining strength and preventing lateral damage such as chipping, with a scratch resistance that limits chip formation to a region no greater than twice the scratch width, and a crack initiation threshold of at least 10 kgf, making it suitable for use in electronic devices and other applications like vehicle windshields.
Implementation Method 1
The aluminoborosilicate glass is ion exchangeable
Implementation Method 2
providing enhanced scratch resistance and crack initiation threshold through compressive stress and densification upon indentation
Data Source
AI summary
A glass and an enclosure, including windows, cover plates, and substrates for mobile electronic devices comprising the glass. The glass has a crack initiation threshold that is sufficient to withstand direct impact, has a retained strength following abrasion that is greater than soda lime and alkali aluminosilicate glasses, and is resistant to damage when scratched. The enclosure includes cover plates, windows, screens, and casings for mobile electronic devices and information terminal devices.