Transparent Substrate Thin-Film Multilayer Solar Factor and Color Neutrality
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Triple glazing with conventional stacks of thin layers has a limited solar factor and exhibits an undesirable yellow/green color in transmission, which is not considered neutral.
Innovation Solution
A transparent substrate made of glass with a stack of thin layers comprising a single metallic layer with infrared reflection properties sandwiched between two non-metallic dielectric coatings, where the overlying dielectric coating consists of a specific sequence of high and low refractive index layers, optimized in thickness and refractive index difference, to enhance the solar factor and achieve a more neutral color in transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional stacks of thin layers with two dielectric layers of refractive index close to 2 are used, then the metallic functional layer is antireflected in the visible domain, but the solar factor is limited and the transmission color becomes yellow/green (non-neutral)
Solution Approach 1:
The patent changes the refractive index parameters of the dielectric layers. Instead of using two layers with refractive index close to 2, it employs a first dielectric layer with refractive index between 1.9-2.3 and a second dielectric layer with refractive index between 1.3-1.8. This parameter change in the optical properties of the coating layers enables both high solar factor and neutral transmission color by optimizing the interference conditions for different wavelengths.
Solution Approach 2:
The patent uses a composite structure of two different dielectric materials with distinct refractive indices. The combination of a high refractive index material (first dielectric layer) and a low refractive index material (second dielectric layer) creates a multi-layer optical coating that simultaneously achieves high solar radiation transmission and neutral color appearance by controlling light interference patterns.
2Use of energy by moving object
If the physical thickness of high refractive index layers is increased to improve solar factor, then more solar energy is transmitted, but the color neutrality is compromised
Solution Approach 1:
The patent optimizes the thickness parameters of both dielectric layers simultaneously. The first dielectric layer has thickness of 10-50 nm and the second dielectric layer has thickness of 50-150 nm. By carefully controlling these thickness parameters in combination with the refractive index parameters, the coating achieves optimal balance between solar energy transmission and color neutrality through constructive and destructive interference effects.
Solution Approach 2:
The patent assigns different optical properties to different layers of the coating. The first dielectric layer with higher refractive index is positioned closer to the metallic layer, while the second dielectric layer with lower refractive index is positioned farther away. Each layer has specific thickness and refractive index characteristics tailored to its position, creating localized optical functions that collectively achieve high solar transmission with neutral color.
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 significantly increases the solar factor and improves the color neutrality in transmission, as demonstrated by increased solar factor values and reduced color components in the LAB system, while maintaining neutral reflection colors.
Implementation Method 1
a functional layer of metallic type capable of acting on solar radiation and/or infrared radiation of great length wave
Implementation Method 2
a functional layer of metallic type capable of acting on solar radiation and/or infrared radiation of great length wave
Implementation Method 3
the purpose of these coatings which surround the metallic functional layer is to 'anti-reflect' this metallic functional layer in the visible domain, to maintain high transmission in the visible domain
Implementation Method 4
two dielectric layers with a refractive index close to 2
Data Source
AI summary
The invention relates to a transparent substrate equipped with a thin-film multilayer comprising a metal film that reflects in the infrared, said film being placed between two non-metal dielectric coatings located subjacent and superjacent said film, the subjacent dielectric coating comprising a sequence of thin films deposited in the following order: at least one high-refractive-index film, the physical thickness of the high-refractive-index film or the sum of the physical thicknesses of the high-refractive-index films lying between 15 and 40 nm; and, at least one low-refractive-index film, the physical thickness of the low-refractive-index film or the sum of the physical thicknesses of the low-refractive-index films lying between 40 and 120 nm, the difference between the refractive index of the one or more high-refractive-index films and the one or more low-refractive-index films lying between 0.7 and 1.2 and preferably between 0.8 and 1.1. The invention increases the solar factor of a multiple glazing unit while providing an acceptable colour, especially in transmission, for a multiple glazing unit, which colour is in particular less green and even in addition less yellow.