Glass Substrate Nanocrystals Enhance Surface Strength
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Solution Overview
Problem
The challenge is to create a glass substrate that is both durable and thin, suitable for modern electronic devices, while maintaining high transmittance and impact resistance, as existing glass substrates struggle to balance strength and weight in slim, portable designs.
Innovation Solution
A glass substrate is developed with a base composition of SiO2, Al2O3, and Li2O, incorporating nanocrystals with diameters between 5 nm and 10 nm, specifically Li2Si2O5, Li2SiO3, LiAlSi2O6, or LiAlSi3O3, which are integrated into a compressive stress layer near the surface, enhancing strength and impact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the glass substrate is made thinner to reduce weight, then the weight decreases, but the strength and impact resistance deteriorate
Solution Approach 1:
The glass substrate is designed as a composite material containing nanocrystals (5-10 nm diameter) dispersed within the glass matrix. The nanocrystals include phases such as Li2SiO3, Li2Si2O5, LiAlSi2O6, and LiAlSi3O3, which provide reinforcement while maintaining the thin profile required for weight reduction.
Solution Approach 2:
Compressive stress layers are formed locally at the surfaces of the glass substrate through ion exchange treatment. This creates a gradient in mechanical properties, with the surface regions having enhanced compressive strength to resist impact, while the bulk material remains thin and lightweight.
2Strength
If nanocrystals are added to enhance strength, then the strength improves, but the manufacturing complexity increases
Solution Approach 1:
The glass composition is pre-formulated with specific oxide components (SiO2, Al2O3, Li2O, and additional oxides) that serve as precursors for nanocrystal formation. During a single heat treatment process at 400-700°C, these precursors transform into nanocrystals, eliminating the need for separate nanocrystal synthesis steps.
Solution Approach 2:
The manufacturing process utilizes controlled heat treatment at moderate temperatures (400-700°C) to induce nanocrystal formation from the glass matrix. This temperature range is sufficient to activate crystallization of the pre-loaded oxide components while remaining compatible with standard glass processing equipment and existing manufacturing workflows.
3Length of moving object
If the glass substrate is made thinner for portable devices, then the portability improves, but the impact resistance deteriorates
Solution Approach 1:
Compressive stress layers are formed on the surface of the thin glass substrate through ion exchange treatment before the product is put into service. These pre-formed compressive stresses act as a cushion against impact forces, preventing crack initiation and propagation at the vulnerable thin edges and surfaces.
Solution Approach 2:
The thin glass substrate is reinforced with dispersed nanocrystals (5-10 nm diameter) that act as strengthening agents. These nanocrystals impede crack propagation and enhance the overall mechanical integrity of the thin substrate, providing impact resistance comparable to thicker glass while maintaining the desired thin profile.
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 substrate achieves enhanced durability and impact resistance while maintaining high transmittance of visible light, making it suitable for use in electronic devices such as displays, with the nanocrystals improving surface strength without compromising optical properties.
Implementation Method 1
heat-treating the base glass at a first temperature, in which the first temperature is in a range from (Tg+50)° C. to (Ts+150)° C.
Data Source
AI summary
A glass substrate and a method for manufacturing the glass substrate are provided. The glass substrate may include a base glass including SiO2, Al2O3, and Li2O, and nanocrystals having an average diameter in a range from about 5 nm to about 10 nm, thereby exhibiting enhanced surface strength properties while maintaining good transmittance properties. The method may include a step of heat-treating a base glass, thereby providing a glass substrate having enhanced strength properties.