Transparent Substrate Stack: Doped Tungsten Oxide for Solar Control
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Solution Overview
Problem
Existing functional stacks for solar control glazings in residential applications struggle to achieve high light transmission, low solar factor, and low emissivity, making them unsuitable for providing sufficient natural illumination and energy efficiency.
Innovation Solution
A transparent substrate with a functional stack comprising a tungsten oxide layer doped with elements from group 1 of the IUPAC nomenclature, such as cesium, is used between dielectric modules, enhancing selectivity and energy performance by magnetron sputtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If infrared radiation absorbent layers are used as functional layers in the functional stack, then solar control function is improved, but emissivity increases and becomes incompatible with residential applications
Solution Approach 1:
The patent changes the chemical composition parameters of the functional layer by doping tungsten oxide with group 1 elements (particularly cesium) at controlled concentrations (0.01 to 0.2 molar ratio). This parameter change transforms the material's optical properties to achieve simultaneous infrared absorption and low emissivity, resolving the contradiction between solar control and energy loss.
Solution Approach 2:
The patent creates a composite functional layer by combining tungsten oxide with group 1 element dopants within a dielectric module structure. This composite approach enables the layer to exhibit multiple functions: infrared absorption for solar control, low emissivity for energy conservation, and maintained optical transparency, thereby resolving the trade-off between solar protection and thermal insulation.
2Object-affected harmful factors
If high absorption of infrared radiation is achieved to reduce solar factor, then solar control function is improved, but light transmission in visible range decreases
Solution Approach 1:
The patent applies local quality by designing the functional stack with different layers having specialized functions: the doped tungsten oxide layer specifically targets infrared absorption while the surrounding dielectric layers (such as silicon nitride, zinc oxide, tin oxide) are optimized for visible light transmission. This spatial differentiation of optical properties allows simultaneous infrared blocking and visible light transmission.
Solution Approach 2:
The patent modifies the optical parameters of the functional layer through controlled doping of tungsten oxide with group 1 elements. By adjusting the dopant concentration and oxidation state, the material's absorption spectrum is tuned to preferentially absorb infrared radiation while maintaining high transparency in the visible range, thus resolving the contradiction between solar control and illumination.
3Object-affected harmful factors
If metallic functional layer based on silver is used for infrared reflection, then solar control is improved, but optical effects of reflection and refraction in visible range occur
Solution Approach 1:
The patent introduces dielectric modules as intermediary layers surrounding the functional layer. These dielectric layers (comprising materials like silicon nitride, zinc oxide, or tin oxide) act as optical mediators that eliminate unwanted reflection and refraction effects at the interfaces, while allowing the inner functional layer to perform infrared absorption. This intermediary structure preserves optical clarity in the visible range.
Solution Approach 2:
The patent replaces the simple metallic silver layer with a composite structure consisting of a doped tungsten oxide functional layer embedded within dielectric modules. This composite architecture combines the infrared absorption capability of the functional layer with the optical clarity and reflection-neutralizing properties of the dielectric materials, thereby resolving the contradiction between solar control and optical clarity.
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 high selectivity, low solar factor, and maintained color neutrality, supporting improved energy efficiency and illumination while being cost-effective and adaptable to existing deposition methods.
Implementation Method 1
The layer has a transparency to radio waves and a 'solar control' function by virtue, in particular, of its high absorption of infrared radiation
Implementation Method 2
a metallic functional layer, in particular based on silver, allowing the reflection of a part of the electromagnetic radiation, in particular infrared radiation
Implementation Method 3
in order to neutralize the optical effects of reflection and refraction in the visible range
Data Source
AI summary
A transparent substrate provided with a functional stack of thin layers on at least one of its faces, the functional stack including, starting from the substrate, at least one metallic functional layer placed between two dielectric modules of thin layers, and wherein at least one of the dielectric modules of thin layers includes a layer of tungsten oxide, and the tungsten oxide includes at least one doping element selected from the chemical elements of group 1 according to the IUPAC nomenclature.