Coated Glass Articles with Composite Optical Coatings
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Solution Overview
Problem
Current coated glass articles for electronic device covers fail to simultaneously achieve optimal scratch-resistance, drop performance, retained strength after surface damage, and strong optical performance characteristics, often compromising mechanical properties for enhanced optical features.
Innovation Solution
A coated glass article with a specific composition of SiO2, Al2O3, P2O5, B2O3, Li2O, Na2O, and K2O, combined with an optical coating featuring alternating high and low refractive index layers, providing enhanced hardness, scratch-resistance, and optical performance, including high transmittance and low reflectance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If optical coatings are applied to enhance optical properties (transmittance and reflectance), then optical performance is improved, but mechanical properties (drop resistance and retained strength) deteriorate
Solution Approach 1:
The patent applies a multi-layer composite coating structure consisting of a scratch-resistant layer and an anti-reflective coating with multiple alternating high and low refractive index layers. This composite structure simultaneously provides scratch resistance, optical performance enhancement, and maintains mechanical strength by combining materials with complementary properties in a layered configuration.
Solution Approach 2:
The optical coating is segmented into multiple distinct layers with different refractive indices (high and low alternating layers). Each layer performs a specific function: some layers provide scratch resistance while others optimize optical performance. This segmentation allows independent optimization of mechanical and optical properties without compromise.
2Object-affected harmful factors
If coatings are applied to improve scratch-resistance, then scratch-resistance is improved, but mechanical properties (drop performance and retained strength) deteriorate
Solution Approach 1:
The coating system uses composite materials where a scratch-resistant layer is combined with an anti-reflective coating containing multiple refractive index layers. This composite structure provides scratch resistance through the hard outer layer while the underlying layers and glass substrate composition maintain drop performance and retained strength.
Solution Approach 2:
The scratch-resistant layer is positioned specifically at the surface where scratch resistance is most needed, while the anti-reflective coating layers are positioned beneath it. This local quality approach applies different material properties to different regions of the coating system according to their specific functional requirements.
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 coated glass article achieves a combination of scratch-resistance, drop performance, retained strength, and strong optical performance, with a maximum hardness of 10-30 GPa and retained strength of over 250 MPa, while maintaining high transmittance and low reflectance.
Implementation Method 1
The optical coating may form an anti-reflective surface
Implementation Method 2
an anti-reflective coating comprising a plurality of alternating high refractive index and low refractive index layers
Data Source
AI summary
A coated glass article is described herein that includes a glass substrate including a first major surface and a second major surface. The first major surface and the second major surface may be opposing sides of the glass substrate. The coated glass article includes an optical coating disposed on the first major surface of the glass substrate. The coated glass article may have a retained strength after impact damage of greater than or equal to 250 MPa. The coated glass article may have a failure height of greater than or equal to 50 cm as measured according to a Drop Test Method on 80 grit sandpaper. In addition, the substrate can comprise 5.0-10.0 mol % Li2O, 1.0-10.0 mol % Na2O, and a lithium to sodium molar ratio (Li2O:Na2O) from 1.2 to 2.0.