AgNiCr Contact Layer for Low-E Coating Visible Transmission

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Solution Overview

Problem

Low-E coatings with silver-based infrared reflecting layers face challenges in achieving high visible transmission and light-to-solar gain ratio while maintaining low emissivity and sheet resistance, often resulting in poor performance with low light-to-solar gain ratio values.

Innovation Solution

Incorporating a contact layer comprising Ag, Ni, and Cr directly over the silver-based IR reflecting layer, which increases visible transmission and light-to-solar gain ratio without sacrificing emissivity and sheet resistance, by sputter depositing these layers on a glass substrate with specific atomic percentages and orientations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a NiCr contact layer is used over the silver-based IR reflecting layer, then the coating provides protection and low sheet resistance, but visible transmission and light-to-solar gain ratio are reduced

Engineering Contradiction:

Improveprotective functionVSAvoidvisible transmission

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The patent applies composite materials by creating a multi-layer contact layer system consisting of AgNiCr (silver-nickel-chromium) and AgAl (silver-aluminum) layers. This composite structure combines the protective properties of NiCr with the high visible transmission characteristics of Ag-based alloys, achieving both protection and optical performance simultaneously

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the compositional parameters of the contact layer by incorporating specific ratios of Ag (40-80 atomic%), Ni (10-30 atomic%), Cr (5-20 atomic%), and Al (5-20 atomic%). This parameter optimization allows the contact layer to maintain low sheet resistance while achieving high visible transmission and light-to-solar gain ratio

Inventive Principle:

Principle #35Parameter changes

2Reliability

If traditional low-E coating structures are used, then low emissivity is achieved, but light-to-solar gain ratio remains low (around 1.0 or less)

Engineering Contradiction:

Improvelow emissivityVSAvoidlight-to-solar gain ratio

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The patent applies local quality by optimizing the composition and thickness of specific layers at different positions in the coating structure. The AgNiCr/AgAl contact layer is designed with specific local compositions (Ag 40-80%, Ni 10-30%, Cr 5-20%, Al 5-20%) to provide different functions: Ag for high transmission, NiCr for protection, and Al for enhanced optical performance

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining multiple metal alloy layers (AgNiCr and AgAl) with the silver-based IR reflecting layer. This composite structure achieves both low emissivity (through the silver layer) and high light-to-solar gain ratio (through the optimized AgNiCr/AgAl contact layers)

Inventive Principle:

Principle #40Composite materials

3Illumination intensity

If Ag is added to the NiCr contact layer, then visible transmission increases by 1-4%, but the complexity of the coating structure increases

Engineering Contradiction:

Improvevisible transmissionVSAvoidcoating structure complexity

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into a single integrated contact layer structure. The AgNiCr layer and AgAl layer are combined to simultaneously provide protection, maintain low sheet resistance, and achieve high visible transmission. This merging approach increases performance without proportionally increasing structural complexity

Inventive Principle:

Principle #5Merging (Combining)

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 effectively enhances visible transmission by 1-4% and increases light-to-solar gain ratio while maintaining low emissivity and sheet resistance, making it suitable for applications like monolithic windows and insulated glass units.

Implementation Method 1

In a first step, a dielectric layer is sputter deposited on a glass substrate. In a second step, a metallic or substantially metallic infrared (IR) reflecting layer comprising silver is sputter deposited on the glass substrate located over at least the first dielectric layer. In a third step, a contact layer comprising Ag, Ni and Cr is sputter deposited on the glass substrate located over and directly contacting the IR reflecting layer comprising silver.

Methodology Applied

Scientific EffectSputtering: Sputtering

Data Source

PatentUS10696584B1Coated article with low-E coating having protective contact layer including Ag, Ni, and Cr for protecting silver based IR reflecting layer(s), and method of making same

Publication Date: 2020.06.30 GUARDIAN EURO S A R L

AI summary

A coated article includes a low emissivity (low-E) coating supported by a glass substrate. The low-E coating includes at least one silver (Ag) based infrared (IR) reflecting layer(s) that is provided adjacent to and contacting at least one contact layer of or including Ag, Ni and Cr. The provision of a contact layer(s) including at least Ag, Ni and Cr, directly over and contacting a silver-based IR reflecting layer, has been found to advantageously increase visible transmission (Tvis) of the low-E coating. Such low-E coating may be used in applications such as monolithic windows, insulated glass (IG) window units, and the like.