Laminated Glass Core-Clad Structure for Scratch Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Glass articles in electronic devices are prone to scratching and drop-induced damage, which can lead to catastrophic failure due to their susceptibility to regular contact and impact, necessitating the development of alternative glass compositions that offer enhanced resistance to both scratching and impact damage.
Innovation Solution
A laminated glass article comprising a glass core layer with a higher elastic modulus and ion exchangeable clad layers of different compositions, where the clad layers are fused directly to the core layer, creating a compressive stress region that enhances resistance to scratches and drop-induced breakage, with specific characteristics such as varying alkali oxide concentrations and thermal expansion coefficients to achieve optimal stress distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single glass composition is used for the entire glass article, then manufacturing is simple and uniform, but the glass is susceptible to both scratching and drop-induced damage
Solution Approach 1:
The glass article is divided into multiple layers with different compositions: a core glass layer and one or more clad glass layers. Each layer is optimized for specific properties - the core layer provides structural strength and impact resistance, while the clad layers provide scratch resistance and surface durability. This segmentation allows each layer to perform its specific function optimally.
Solution Approach 2:
Different regions of the glass article are given different properties through the use of multiple glass compositions. The core layer has properties optimized for bulk strength and impact resistance, while the clad layers have properties optimized for surface hardness and scratch resistance. This local differentiation of material properties resolves the contradiction between overall reliability and compositional simplicity.
2Reliability
If the glass article uses multiple glass layers with different compositions, then scratch and impact resistance is improved, but manufacturing complexity increases
Solution Approach 1:
Multiple glass layers are combined into a single integrated structure where the core glass layer and clad glass layers are fused together. This merging approach, while more complex than single-layer manufacturing, allows the different glass compositions to work synergistically to provide both scratch and impact resistance that cannot be achieved with a single composition.
3Strength
If the glass article is designed with thin clad layers, then the overall structure remains lightweight and simple, but the compression stress depth is reduced
Solution Approach 1:
The invention optimizes the thickness parameter of the clad layers to achieve the desired balance. By controlling the clad layer thickness to be within specific ranges (e.g., 1-50 micrometers), the article achieves sufficient compression stress depth while maintaining overall structural simplicity and weight efficiency. The parameter optimization allows thin layers to provide adequate protection without excessive thickness.
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 laminated glass article exhibits improved resistance to scratching and drop-induced breakage, with a deep depth of compression and high Knoop scratch initiation threshold, effectively addressing the limitations of existing glass compositions in electronic devices.
Implementation Method 1
at least one glass clad layer fused directly to the glass core layer
Implementation Method 2
The at least one glass clad layer may be formed from an ion exchangeable clad glass composition different than the ion exchangeable core glass composition
Data Source
AI summary
Scratch and damage resistant laminated glass articles are disclosed. According to one aspect, a laminated glass article may include a glass core layer formed from an ion exchangeable core glass composition and includes a core glass elastic modulus EC and at least one glass clad layer fused directly to the glass core layer. The at least one glass clad layer may be formed from an ion exchangeable clad glass composition different than the ion exchangeable core glass composition and includes a clad glass elastic modulus ECL. The laminated glass article may have a total thickness T and the at least one glass clad layer may have a thickness TCL that is less than 30% of the total thickness T. EC may be at least 5% greater than ECL.