Transparent Thin-Film Glazing for Solar Control and RF Transparency
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Solution Overview
Problem
Existing motor vehicle glazings struggle to balance low solar factor, high light transmission, and radiofrequency transparency, as metallic functional layers block radio electromagnetic waves, leading to poor telecommunications.
Innovation Solution
A transparent substrate with a stack of thin layers comprising a first dielectric module, an absorbent tungsten oxide layer doped with group 1 elements, and a second dielectric module with alternating low- and high-index layers, eliminating metallic layers to ensure radiofrequency transparency while modulating optical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If metallic functional layers are used in solar control glazings, then solar control performance is improved, but radiofrequency transparency deteriorates
Solution Approach 1:
The patent replaces metallic layers with non-metallic absorbing layers made of oxides and nitrides, fundamentally changing the material parameter from conductive metal to insulating ceramic. This allows the glazing to absorb infrared radiation while maintaining radiofrequency transparency, as the non-metallic materials do not block radio waves like metallic layers do.
Solution Approach 2:
The patent uses composite structures combining multiple oxide and nitride layers (such as tungsten oxide, titanium oxide, silicon oxide, silicon nitride) with different optical and electrical properties. These composite non-metallic layers achieve both solar control through infrared absorption and radiofrequency transparency, resolving the contradiction between energy control and communication signal transmission.
2Reliability
If non-metallic absorbing layers are used instead of metallic layers, then radiofrequency transparency is improved, but solar control performance deteriorates
Solution Approach 1:
The patent optimizes the thickness parameters of non-metallic absorbing layers to be in the range of 5-50 nm, which is sufficient to absorb infrared radiation while maintaining radiofrequency transparency. By precisely controlling the thickness parameter, the glazing achieves effective solar control without compromising communication signal transmission.
Solution Approach 2:
The patent designs different layers with specific local functions: oxide layers (tungsten oxide, titanium oxide) provide infrared absorption for solar control, while nitride layers (silicon nitride, aluminum nitride) provide structural support and additional optical control. Each layer is optimized for its specific function, achieving both solar control and radiofrequency transparency through localized material properties.
3Loss of energy
If multiple oxide and nitride layers are stacked, then solar selectivity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the solar control function into multiple specialized layers: infrared-absorbing oxide layers (tungsten oxide, titanium oxide) and structural nitride layers (silicon nitride, aluminum nitride) alternating in a stack. Each segment performs a specific function, allowing independent optimization of solar selectivity while maintaining manufacturability through modular layer deposition.
Solution Approach 2:
The patent specifies precise thickness ranges for each layer type (oxides: 5-50 nm, nitrides: 10-100 nm) to optimize solar selectivity while ensuring manufacturability. These parameter specifications provide clear manufacturing guidelines, reducing complexity by defining exact deposition parameters rather than requiring complex real-time adjustments during production.
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 gain of up to 30% on solar selectivity and maintains sufficient light transmission, approximately 70%, with improved durability and radiofrequency transparency, enhancing telecommunications quality.
Implementation Method 1
an absorbent tungsten oxide layer; wherein the tungsten oxide comprises at least one doping element selected from the chemical elements of group 1
Implementation Method 2
a second dielectric module of several thin layers; Said second dielectric module preferably comprises at least one succession of two layers with a low-index layer and a high-index layer
Data Source
AI summary
A transparent substrate (1000) provided on one of its main surfaces with a stack (1001) of thin layers, said stack (1001) of layers consisting of the following layers starting from the substrate (1000):a first dielectric module (1002) of one or more thin layers;an absorbent layer (1003) of tungsten oxide;a second dielectric module (1004) of several thin layers;wherein the tungsten oxide comprises at least one doping element selected from the chemical elements of group 1 according to the IUPAC nomenclature.