Glazing Unit Reflection-Reducing Layer Porous Composite
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Solution Overview
Problem
Existing glazing technologies face challenges in maximizing energy transmission through glass while minimizing reflections and ensuring stability against weather and mechanical influences, particularly with anti-reflective coatings that are water-soluble or prone to irregular thickness and contamination issues.
Innovation Solution
A glazing element with a reflection-reducing layer deposited using PVD or CVD methods, featuring cavities that reduce the refractive index, providing a broadband antireflection effect and improved stability, along with a cover layer for enhanced protection, and a gradient composition for optimal optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If anti-reflective coatings are applied to reduce reflections, then energy transmission is improved, but the coatings become water-soluble and unstable against weather and mechanical influences
Solution Approach 1:
The patent uses a composite material consisting of silicon dioxide particles (inorganic filler) embedded in an organic binder matrix. This composite structure combines the optical properties of silicon dioxide with the adhesive and mechanical properties of the organic binder, creating a coating that is both anti-reflective and weather-stable. The composite material allows the coating to maintain its integrity under weather and mechanical stress while preserving the desired optical performance.
Solution Approach 2:
The patent employs a porous structure with cavities formed by removing part of the organic binder, creating voids that scatter light and reduce reflections. The porous material maintains mechanical integrity through the remaining binder network while achieving the optical effect of reduced reflectivity. The cavities create a gradient in refractive index that enhances the anti-reflective properties without compromising the coating's stability.
2Ease of manufacture
If dipping or spraying process is used to apply anti-reflective layer, then layer can be applied to substrate, but uniform layer thickness cannot be achieved due to change in thickness towards edge region
Solution Approach 1:
The patent changes the physical parameters of the coating application process by using a suspension with specifically controlled particle size distribution (0.1-10 μm) and viscosity characteristics. By adjusting these parameters, the coating achieves uniform thickness across the entire substrate surface, including edge regions, when applied by dipping or spraying. The particle size and binder composition are optimized to ensure consistent flow and deposition characteristics.
3Ease of manufacture
If dipping process is used to apply coating, then coating can be applied to substrate, but all surfaces are coated equally which is problematic when coating on both sides is not useful
Solution Approach 1:
The patent segments the coating process into distinct stages: first applying the anti-reflective coating to the required surface, then removing excess coating from the opposite side before it dries. This segmentation allows selective coating of only the necessary surfaces while maintaining the simplicity of the dipping process. The method involves controlled withdrawal and removal steps that prevent unwanted coating on the second side without requiring complex masking or positioning systems.
4Loss of energy
If open-pored structure with cavities is created to reduce refractive index, then anti-reflection effect is improved, but water settles in open pores reducing the refractive index difference
Solution Approach 1:
The patent uses a hydrophobic binder that repels water and prevents it from penetrating into the porous structure. The binder acts as a protective barrier that maintains the air-filled cavities dry, preserving the refractive index difference necessary for the anti-reflective effect. This approach is simpler and more effective than attempting to seal the pores, as it maintains the open-pored structure's optical benefits while preventing water intrusion through chemical repulsion.
5Loss of energy
If magnesium fluoride layer is deposited by CVD process, then reflection is reduced, but the layer is water-soluble and not stable for outdoor use
Solution Approach 1:
The patent changes the material composition parameters by replacing magnesium fluoride with an organic-inorganic composite system. The new coating uses an organic binder with specific chemical properties (hydrophobicity, adhesion) combined with silicon dioxide particles. This parameter change transforms the coating from a water-soluble inorganic salt layer to a weather-resistant composite that maintains anti-reflective properties while achieving the required stability for outdoor applications.
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 enhances energy transmittance by up to 1.1 W/cm²/K, maintains stability over time, and prevents optical defects, while maintaining color neutrality and ease of cleaning, thus improving the overall efficiency of energy transmission through the glazing element.
Implementation Method 1
an initial layer containing silicon, oxygen, carbon and hydrogen is applied to a surface of the first transparent substrate (2) by a PVD process
Implementation Method 2
The initial layer, which consists of at least one layer containing silicon, oxygen, carbon and hydrogen, is deposited by a PVD process, a CVD process or a combination of both processes
Implementation Method 3
Cavities are formed in the anti-reflective layer. The cavities formed in the reflection-reducing layer lead to a reduction in the refractive index in the reflection-reducing layer
Implementation Method 4
The solvents are then at least partially removed from the applied layer by means of a mostly thermal post-treatment, so that the silicon dioxide spheres sinter to form a solid composite. This structure contains cavities which, due to multiple reflections, lead to a reduction in the refractive index
Implementation Method 5
cavities are then produced in the reflection-reducing layer by reducing the carbon and hydrogen content in the layer after the starting layer has been applied. This creates cavities of small size in the layer and a homogeneous layer results
Implementation Method 6
the concentration of carbon in the vicinity of the side of the layer facing away from the substrate being smaller than in the vicinity of the substrate
Data Source
AI summary
Glazing element comprises a first light-permeable substrate (2) arranged next to a second light-permeable substrate (3). A reflection-reducing layer (9,9) is deposited on the substrate surfaces (5,6,7,8) using a PVD or CVD method. Hollow chambers are formed in the reflection-reducing layer.