Doped Tungsten Oxide Glazing Stack for Solar and Light Control
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Solution Overview
Problem
Existing functional stacks for glazing in the building and construction markets fail to meet the requirements of high light transmission, low solar factor, and low emissivity, making them unsuitable for residential applications.
Innovation Solution
A transparent substrate with a functional stack comprising a tungsten oxide layer doped with elements from Group 1 of the IUPAC nomenclature, sandwiched between dielectric modules, enhances selectivity and energy performance by reducing solar factor and increasing light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a functional stack uses only infrared radiation-absorbing layers, then solar control function is improved, but emissivity increases making it incompatible with residential applications
Solution Approach 1:
The patent employs a composite functional stack combining multiple material layers with distinct properties: a metallic layer (silver or aluminum) for infrared reflection, a tungsten oxide layer for infrared absorption, and dielectric layers for optical compensation. This composite structure achieves both low emissivity and high solar control by leveraging the complementary functions of each material layer.
Solution Approach 2:
The functional stack is segmented into distinct layers, each performing a specific function: the metallic layer handles infrared reflection, the tungsten oxide layer manages infrared absorption, and dielectric layers provide optical compensation. This segmentation allows independent optimization of each layer's properties to achieve the overall performance targets of low emissivity and high solar control.
2Illumination intensity
If a functional stack aims for high light transmission in the visible range, then natural illumination is improved, but solar factor control deteriorates
Solution Approach 1:
The patent applies local quality by designing layers with wavelength-selective properties: the metallic and tungsten oxide layers are optimized to absorb and reflect infrared radiation while remaining transparent to visible light, whereas the dielectric layers are specifically engineered to compensate for optical effects only in the visible range. This spatial and spectral differentiation allows simultaneous achievement of high light transmission and effective solar factor control.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the thickness, composition, and optical constants of each layer to achieve wavelength-selective performance. The dielectric layers' refractive indices and thicknesses are optimized to counteract reflection and refraction effects in the visible range, while the infrared-active layers' parameters are tuned for maximum infrared interaction, enabling independent control of visible transmission and solar factor.
3Object-affected harmful factors
If a functional stack uses a metallic functional layer based on silver, then infrared reflection is improved, but optical effects of reflection and refraction in the visible range worsen
Solution Approach 1:
The patent introduces dielectric layers as intermediary elements between the metallic functional layer and the external environment. These dielectric layers serve as optical mediators that compensate for the reflection and refraction effects generated by the metallic layer in the visible range, while allowing the metallic layer to maintain its infrared reflection function. The dielectric layers effectively decouple the optical problems in the visible range from the infrared reflection function.
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 functional stack achieves a solar factor reduction of at least 2% and light transmission increase of at least 1%, while maintaining neutral color and compatibility with existing deposition methods, thus meeting residential market needs.
Implementation Method 1
The layer has a 'solar control' function due to its strong absorption of near-infrared radiation
Implementation Method 2
A particularly used type of functional stack of thin layers comprises a metallic functional layer, in particular based on silver, allowing the reflection of part of the electromagnetic radiation, in particular infrared radiation
Implementation Method 3
The metallic functional layer is generally arranged between two dielectric assemblies, also called dielectric modules, in order to neutralize the optical effects of reflection and refraction in the visible range
Implementation Method 4
a tungsten oxide-based layer deposited by sputtering using a tungsten oxide target comprising chemical elements selected from hydrogen, alkali, alkaline earth, and rare earth
Data Source
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AI summary
The invention relates to a transparent substrate (1000) provided with a functional stack (1001) of thin layers on at least one of its faces (1000a, 1000b), the functional stack (1001) comprising, starting from the substrate (1000), at least one metal functional layer (1003) placed between two thin-film dielectric modules (1002,1004), and wherein at least one of the thin-film dielectric modules (1002,1004) comprises a layer (1002a, 1004a) of tungsten oxide, and the tungsten oxide comprises at least one dopant element selected from among the chemical elements of group 1 according to the IUPAC nomenclature.