Multilayer Solar-Control Glazing for Neutral Color and Selectivity

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing glazings struggle to achieve a high selectivity (ratio of light transmission to solar factor) greater than 2.1, while maintaining a neutral and aesthetically pleasing appearance, especially in warm climates where low solar factor and suitable light transmission are required for effective insulation and vision.

Innovation Solution

A transparent substrate with a stack of thin layers comprising at least three metallic functional layers, each between two dielectric coatings, with specific thickness ratios and materials, including an absorbent or blocking underlayer, to optimize solar protection and appearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a stack with three metal layers is used to optimize solar protection, then the solar factor is reduced and selectivity is increased, but the light transmission becomes difficult to control within the optimal range

Engineering Contradiction:
Improvesolar factorVSAvoidlight transmission
Core Design Contradiction:
Loss of energyVSIllumination intensity

Solution Approach 1:

The patent applies parameter changes by precisely controlling the thickness of each metal layer and the dielectric layers surrounding them. By adjusting these dimensional parameters during the deposition process, the optical properties of the coating are tuned to achieve both low solar factor and appropriate light transmission. The specific thickness ratios and material compositions are optimized to balance energy rejection with visible light passage.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining multiple metal layers (such as silver, aluminum, or their alloys) with dielectric materials (oxides or nitrides) in a stacked configuration. This composite structure allows each material to contribute its specific properties: metal layers provide solar reflection and selective infrared transmission, while dielectric layers enhance anti-reflective properties and fine-tune optical performance, achieving both energy efficiency and visual comfort.

Inventive Principle:
Principle #40Composite materials

2Loss of energy

If the thicknesses of metal layers are increased to reduce solar factor, then solar protection is improved, but the appearance color becomes less neutral and aesthetically acceptable

Engineering Contradiction:
Improvesolar factorVSAvoidappearance color
Core Design Contradiction:
Loss of energyVSShape

Solution Approach 1:

The patent applies parameter changes by precisely controlling the thickness of each metal layer and the dielectric layers surrounding them. By adjusting these dimensional parameters during the deposition process, the optical properties of the coating are tuned to achieve both low solar factor and appropriate light transmission. The specific thickness ratios and material compositions are optimized to balance energy rejection with visible light passage.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by assigning different thicknesses and material compositions to different layers within the stack. Each metal layer and dielectric layer is locally optimized for its specific function: some layers are thicker to provide strong solar reflection, while others are thinner to maintain neutrality in appearance. This localized optimization across the multi-layer structure achieves both high solar protection and aesthetically pleasing neutral colors.

Inventive Principle:
Principle #3Local quality

3Loss of energy

If selectivity is increased to improve thermal insulation, then energy efficiency is improved, but the compromise between optical performance and aesthetic appearance becomes more difficult to achieve

Engineering Contradiction:
ImproveselectivityVSAvoidoptical and aesthetic compromise
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent uses composite materials by combining multiple metal layers (such as silver, aluminum, or their alloys) with dielectric materials (oxides or nitrides) in a stacked configuration. This composite structure allows each material to contribute its specific properties: metal layers provide solar reflection and selective infrared transmission, while dielectric layers enhance anti-reflective properties and fine-tune optical performance, achieving both energy efficiency and visual comfort.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies parameter changes by precisely controlling the thickness of each metal layer and the dielectric layers surrounding them. By adjusting these dimensional parameters during the deposition process, the optical properties of the coating are tuned to achieve both low solar factor and appropriate light transmission. The specific thickness ratios and material compositions are optimized to balance energy rejection with visible light passage.

Inventive Principle:
Principle #35Parameter changes

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 achieves a high selectivity of 2.1 with neutral colors in reflection and transmission, reducing external and internal reflectance to less than 14% and 17% respectively, suitable for buildings in moderately sunny regions.

Implementation Method 1

a stack of thin layers comprising several functional layers which can act on solar radiation and/or long-wave infrared radiation

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

at least one absorbent layer in the first antireflective coating

Methodology Applied
Scientific EffectAbsorption: Absorption (EM radiation)

Implementation Method 3

each functional layer is disposed between two antireflective coatings each including, in general, several antireflective or dielectric layers

Methodology Applied
Scientific EffectAnti-reflective coating: Anti-Reflective Coating

Data Source

PatentUS12509390B2Substrate provided with a stack having thermal properties
Publication Date: 2025.12.30 SAINT GOBAIN VITRAGE SA

AI summary

A transparent substrate provided with a stack of thin layers includes successively, from the substrate, an alternating arrangement of at least three functional metal layers and four antireflective coatings, each antireflective coating including at least one dielectric layer; the thicknesses and the nature of the different layers being adapted for the production of new solar protection glazing, to be tempered, having high thermal performance (S of approximately 2.1 for LT of the order of 60%) and a neutral color, the colors thereof being stable at an angle.