Zinc-Tin Alloy Terminal Layer for Homogeneous Low-Emissivity Glass

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Solution Overview

Problem

Existing glass substrates with metallic functional layers for infrared and solar radiation reflection exhibit optical inhomogeneities due to inhomogeneous treatment sources and imperfections in the conveying system, leading to variations in light transmission and reflection, and lack homogeneity in appearance.

Innovation Solution

A glass substrate coated with a stack of thin layers featuring a metallic functional layer of silver or silver alloy, surrounded by anti-reflective dielectric layers, with a terminal layer composed of zinc and tin (Sn x Zn y) that oxidizes during infrared radiation treatment, ensuring low emissivity and high light transmission while maintaining homogeneity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a metallic terminal layer is used to increase absorption and reduce treatment power, then the optical characteristics after treatment are improved, but optical inhomogeneities become perceptible due to source inhomogeneity and conveying system imperfections

Engineering Contradiction:
Improvetreatment powerVSAvoidoptical homogeneity
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent changes the chemical composition parameters of the terminal layer by using a Zn-Sn alloy instead of pure metal, and optimizes the thickness parameter to a specific range (0.5-5.0 nm). This composition and parameter optimization ensures uniform oxidation behavior during treatment, reducing optical inhomogeneities while maintaining low emissivity and high light transmission.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite terminal layer made of zinc and tin in a specific ratio (0.55 ≤ x/y ≤ 0.83). This composite material combines the beneficial properties of both metals: zinc provides good oxidation resistance and tin enhances uniformity. The composite structure ensures homogeneous oxidation during infrared treatment, eliminating perceptible optical inhomogeneities while achieving the desired optical characteristics.

Inventive Principle:
Principle #40Composite materials

2Illumination intensity

If the terminal layer oxidizes during treatment to become transparent, then light transmission is improved, but the composition stability must be precisely controlled to avoid inhomogeneity

Engineering Contradiction:
Improvelight transmissionVSAvoidcomposition homogeneity
Core Design Contradiction:
Illumination intensityVSStability of the object's composition

Solution Approach 1:

The patent precisely controls the composition parameters of the terminal layer by defining specific ranges for zinc and tin ratios (0.55 ≤ x/y ≤ 0.83) and thickness (0.5-5.0 nm). These parameter optimizations ensure uniform oxidation kinetics during treatment, allowing the layer to become transparent while maintaining composition homogeneity and avoiding perceptible inhomogeneities.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3201151B1Substrate provided with a stack having thermal properties and having a metal terminal layer
Publication Date: 2021.03.10 SAINT GOBAIN VITRAGE SA
  • EP3201151B1 patent drawingFigure 1~2
  • EP3201151B1 patent drawing

AI summary

The invention relates to a substrate (10) coated on one face (11) with a stack of thin layers (14) having reflective properties for infrared and/or solar radiation comprising at least one metal functional layer (140), in particular made from silver or from a metal alloy containing silver, and at least two anti-reflective coatings (120, 160), said coatings each comprising at least one dielectric layer (122, 164), said functional layer (140) being disposed between the two anti-reflective coatings (120, 160), said stack further comprising a terminal layer (168) that is the layer of the stack that is the furthest from said face (11), characterised in that said terminal layer (168) is a metal layer consisting of zinc and tin, made from SnxZny with a ratio of 0.1 ≤ x/y ≤ 2.4 and having a physical thickness of between 0.5 nm and 5.0 nm, excluding said values, or indeed of between 0.6 nm and 2.7 nm, excluding said values.