Multilayer Coating for Vehicle Window Solar Control

Solution Overview

Problem

Vehicle windows struggle to balance reducing solar gain and heat loss while maintaining passenger comfort by minimizing visible light transmittance and reflectance, which can increase with added coatings.

Innovation Solution

A laminated window assembly with a specific multilayer coating system on glass panes, including a first layer with a refractive index of 1.6 or more, a second layer with a lower refractive index, a third layer with a higher refractive index, and a fourth layer with a dielectric material, along with a polymeric interlayer, to control solar energy transmittance and visible light reflectance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If coatings are added to glass to reduce solar gain and heat loss, then energy efficiency is improved, but visible light reflectance increases

Engineering Contradiction:

Improvesolar gain and heat lossVSAvoidvisible light reflectance

Core Design Contradiction:

Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The coating is divided into multiple distinct layers (first layer with refractive index 1.6 or more, second layer with lower refractive index, third layer with higher refractive index, and fourth layer with dielectric material). Each layer serves a specific optical function, allowing the system to reduce solar gain and heat loss through controlled refraction and reflection at multiple interfaces, while managing the overall visible light reflectance through layered architecture.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different layers of the coating have different local optical properties (refractive indices) tailored to specific functions. The first layer has high refractive index for solar energy control, the second layer has lower refractive index to reduce reflections, the third layer has higher refractive index for additional solar control, and the fourth layer has dielectric properties for fine-tuning optical performance. This local differentiation allows simultaneous optimization of energy efficiency and reflectance management.

Inventive Principle:

Principle #3Local quality

2Illumination intensity

If coatings are added to glass to reduce visible light transmittance, then passenger comfort is improved, but visible light reflectance increases

Engineering Contradiction:

Improvevisible light transmittanceVSAvoidvisible light reflectance

Core Design Contradiction:

Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The coating is divided into multiple distinct layers (first layer with refractive index 1.6 or more, second layer with lower refractive index, third layer with higher refractive index, and fourth layer with dielectric material). Each layer serves a specific optical function, allowing the system to reduce solar gain and heat loss through controlled refraction and reflection at multiple interfaces, while managing the overall visible light reflectance through layered architecture.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different layers of the coating have different local optical properties (refractive indices) tailored to specific functions. The first layer has high refractive index for solar energy control, the second layer has lower refractive index to reduce reflections, the third layer has higher refractive index for additional solar control, and the fourth layer has dielectric properties for fine-tuning optical performance. This local differentiation allows simultaneous optimization of energy efficiency and reflectance management.

Inventive Principle:

Principle #3Local quality

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 reduces visible light transmittance and reflectance, enhances solar energy control, and maintains aesthetic appeal, providing improved passenger comfort and energy efficiency in vehicles.

Implementation Method 1

a first layer deposited over a major surface of the glass pane, wherein the first layer has a refractive index of 1.6 or more and a thickness of 50 nm or less, ii. a second layer deposited over the first layer, wherein the second layer has a refractive index that is less than the refractive index of the first layer and a thickness of 50 nm or less, iii. a third layer deposited over the second layer, wherein the third layer has a refractive index that is greater than the refractive index of the second layer and a thickness of less than 500 nm, iv. a fourth layer deposited over the third layer, wherein the fourth layer has a refractive index that is less than the refractive index of the third layer and a thickness of 100 nm or less

Methodology Applied

Scientific EffectOptical interference: Interference

Data Source

PatentUS11718070B2Laminated window assembly

Publication Date: 2023.08.08 PILKINGTON GRP LTD

AI summary

A laminated window assembly has a first glass pane with a coating formed thereon, a second glass pane, and a polymeric interlayer provided between the first glass pane and the second glass pane. The coating includes a first layer deposited over a major surface of the glass pane, wherein the first layer has a refractive index of 1.6 or more and a thickness of 50 nm or less, a second layer deposited over the first layer, wherein the second layer has a refractive index that is less than the refractive index of the first layer and a thickness of 50 nm or less, a third layer deposited over the second layer, wherein the third layer has a refractive index that is greater than the refractive index of the second layer and a thickness of less than 500 nm, and a fourth layer deposited over the third layer, wherein the fourth layer has a refractive index that is less than the refractive index of the third layer and a thickness of 100 nm or less.