Laminated Glazing With Stable Colored Reflection for Solar Transmittance
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Solution Overview
Problem
Existing laminated glazing systems for solar energy integration face challenges such as security concerns, color stability issues, and production limitations, particularly with conventional quarter-wave-stack-based solutions that result in unsuitable reflectance peak shifts with viewing angle and require thick SiO2 layers, making them impractical for industrial-scale production and architectural integration.
Innovation Solution
A laminated glazing unit with a multi-layered interference filter featuring non-quarter-wave thin-film stacks, where high-index and low-index layers have distinct thicknesses, and a laminating polymer layer, ensuring stable reflectance across various angles and high solar transmittance, while using materials like SiO2, Al2O3, and MgO for optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If quarter-wave-stack-based thin-film coatings are used to achieve colored reflection, then solar transmittance is improved, but color stability deteriorates due to reflectance peak shifts with viewing angle
Solution Approach 1:
The patent modifies the optical parameters of the thin-film stack by using non-quarter-wave thicknesses and varying refractive indices of alternating layers. This changes the interference conditions to produce broad reflectance bands instead of narrow peaks, thereby stabilizing the perceived color across different viewing angles while maintaining high solar transmittance.
Solution Approach 2:
The invention employs composite thin-film structures combining multiple dielectric materials with different refractive indices (e.g., TiO2, SiO2, Nb2O5, Ta2O5) in alternating layers. This composite approach enables precise control over the reflectance spectrum shape, achieving both high solar transmittance and angularly stable color appearance through constructive and destructive interference effects.
2Stability of the object's composition
If thick SiO2 layers are used in conventional designs, then color reflection is achieved, but production speed deteriorates due to limited industrial-scale production capability
Solution Approach 1:
The patent reduces the thickness of individual SiO2 layers from conventional thick designs to thin layers (e.g., 5-50 nm) and compensates by optimizing the overall stack configuration with alternating high and low refractive index materials. This enables achievement of the desired optical effect with thinner total coating, significantly increasing production speed while maintaining color reflection performance.
Solution Approach 2:
The invention replaces thick single-material SiO2 layers with composite multi-layer structures using alternating high-index (TiO2, Nb2O5, Ta2O5) and low-index (SiO2, MgF2) dielectric materials. This composite approach achieves equivalent or superior optical performance with reduced total thickness, enabling faster industrial production.
3Ease of manufacture
If non-tempered, non-laminated glazing is used to simplify structure, then manufacturing is easier, but security requirements are not met for facade installation
Solution Approach 1:
The patent employs laminated glazing composed of multiple glass or plastic layers bonded together with interlayers (e.g., PVB, EVA). This composite structure maintains structural simplicity for manufacturing while achieving the required security performance through the combined strength and adhesion of the layered construction, meeting facade installation requirements.
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 provides stable color perception across angles, enhanced mechanical stability, and improved energy-related parameters, allowing for visually appealing architectural integration of solar energy systems with high solar transmittance and reduced reflectance variations, addressing the shortcomings of conventional systems.
Implementation Method 1
The coating then reflects incident light within a pre-determined spectral bandwidth (defining a colour of the reflected light) thereby at least partially hiding the technical structure of the solar device from view, while transmitting light with the complementary spectrum.
Data Source
AI summary
Laminated (and, in some cases, additionally etched) glazing units for cooperation with solar-energy systems during architectural integration thereof include an optically-transparent substrate in contact with an incident medium, on one side, and with a non-quarter-wave thin-film-stack based interference filter on another side, followed by an exit medium. Embodiments are practically applicable to conceal physical structures disposed behind them and characterized by IR-light transmittance that is enhanced (as compared with conventional glazing units based on quarter-wave thin-film-stacks and similarly utilized) to improve efficiency of a solar-energy system carrying at least a portion of such glazing unit on its front surface. Colour of reflected light perceived as a function of angle is sufficiently stabilized for practical applications. In specific cases, a solar-energy system is integrated inside or with such a glazing unit.