Low-E Coated Glass with Multilayer Dielectric Structure for Durability
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Solution Overview
Problem
Existing low-e coated glass substrates face challenges in achieving high mechanical durability, corrosion resistance, and scratch resistance while maintaining high visible light transmission and low infrared radiation reflection.
Innovation Solution
A layered coating configuration on a glass substrate comprising a first dielectric layer of zinc stannate, a second dielectric layer of TiOx, a zinc-oxide seed layer, a silver IR reflecting layer, a NiCrOx blocking layer, a third dielectric layer of TiOx, a silicon oxynitride layer, and a protective TiOx layer, deposited using sputtering methods, with specific thicknesses and refractive indices to enhance adhesion and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a soft low-e coating is applied to glass substrate, then infrared radiation reflection is improved, but mechanical durability and corrosion resistance deteriorate
Solution Approach 1:
The coating is divided into multiple functional layers: a protective outer layer (silicon oxynitride and TiOx) that provides mechanical durability and corrosion resistance, and an inner low-e layer (silver and aluminum-doped zinc oxide) that provides infrared radiation reflection. This segmentation allows each layer to optimize its specific function without compromising the other.
Solution Approach 2:
The patent uses composite material structures combining different materials with complementary properties: silicon oxynitride for chemical inertness and scratch resistance, TiOx for adhesion and protective properties, silver for infrared reflection, and aluminum-doped zinc oxide as a seed layer. The composite structure achieves both durability and low-e performance simultaneously.
2Strength
If multiple protective layers are added to enhance durability, then mechanical durability and corrosion resistance are improved, but visible light transmission deteriorates
Solution Approach 1:
Each layer is designed with specific local properties: the silicon oxynitride layer provides scratch resistance without significant visible light absorption, the TiOx layers provide adhesion and protection with controlled refractive indices (1.5-2.5), and the metallic layers are optimized for infrared reflection while maintaining visible light transmission. The refractive indices are specifically controlled to minimize optical interference that would reduce visible light transmission.
3Ease of manufacture
If conventional single-layer coatings are used, then manufacturing simplicity is maintained, but scratch resistance and adhesion deteriorate
Solution Approach 1:
The coating system is segmented into distinct functional layers deposited in sequence using sputtering: silicon oxynitride layer (14-34 nm), TiOx layers (7-24 nm each), aluminum-doped zinc oxide seed layer (1-10 nm), silver layer (8-20 nm). This segmentation enables optimization of each layer's properties for specific functions including scratch resistance and adhesion.
Solution Approach 2:
The patent employs composite material architecture combining silicon oxynitride for chemical inertness and scratch resistance, TiOx for adhesion enhancement and protective properties, and metallic layers for infrared reflection. The composite structure achieves superior scratch resistance and adhesion compared to conventional single-layer coatings.
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 solution provides a coated article with improved mechanical durability, corrosion resistance, and scratch resistance, maintaining high visible light transmission and low infrared radiation reflection, with a sheet resistance between 3 and 6 ohms/square and a light transmittance factor/solar factor g ratio greater than 1.3, achieving exceptional spectral performance and color properties.
Implementation Method 1
Low-e coatings are deposited in the vacuum environment with magnetron sputtering
Implementation Method 2
Low emissivity can block infrared (IR) radiation to reduce heat transmission between interiors and the exteriors of the buildings
Data Source
Figure 1
AI summary
Certain example embodiments of this invention relate to glass substrate with low emissivity (low-E) coatings that aused for minimizing heat transmission. Low-e coatings are deposited in the vacuum environment with magnetron sputtering. The coating contains barrier layer systems including multiple dielectric layers advantageously increases layer quality, mechanical durability, corrosion and/or scratch resistance. Coated articles according to certain example embodiments of this invention may be used in the context of insulating glass (IG) window units, vehicle windows, other types of windows, or in any other suitable application.