Switchable Glazing Reflection Layer for Uniform External Color
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Solution Overview
Problem
Glazings with switchable optical properties often result in a nonuniform and aesthetically undesirable appearance when in different switching states, as the color appearance of reflected light varies with the switching state and observation angle, and existing solutions are either costly or produce undesirable color shifts.
Innovation Solution
A glazing with a single, homogeneous reflection layer having a refractive index between 1.6 and 2.55 and a thickness that adjusts the external reflection color independently of the switching state, ensuring a uniform appearance regardless of the switching state or observation angle, using materials like silicon nitride or tin oxide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a multi-layer reflection coating structure is used to ensure uniform appearance, then the appearance uniformity is improved, but the production time and cost increase
Solution Approach 1:
The invention separates the reflection function from the anti-reflection function into distinct layers. The reflection layer (first layer) provides thermal radiation reflection, while the anti-reflection layer (second layer) minimizes visible light reflection. This segmentation allows each layer to be optimized independently, achieving uniform appearance with a simpler two-layer structure rather than complex multi-layer coatings.
Solution Approach 2:
The invention extracts the anti-reflection property as a separate functional layer (second layer with refractive index 1.3-1.7) distinct from the reflection layer. By taking out the anti-reflection function into its own layer with specific material properties, the patent achieves uniform appearance without requiring complex multi-layer interference coatings, thereby simplifying production.
2Stability of the object's composition
If a multi-layer reflection coating structure is used to ensure uniform appearance, then the appearance uniformity is improved, but the production cost increases
Solution Approach 1:
The invention segments the optical functions into two distinct layers with different refractive indices. The first layer (reflection layer) handles thermal radiation, while the second layer (anti-reflection layer) handles visible light. This segmentation enables the use of conventional, cost-effective materials and deposition techniques rather than expensive custom multi-layer interference coatings.
Solution Approach 2:
The invention changes the refractive index parameter of the second layer to be between 1.3 and 1.7, which is lower than the substrate refractive index. This parameter selection creates anti-reflection through impedance matching, achieving uniform appearance without requiring complex multi-layer structures with precise thickness control, thereby reducing production cost.
3Adaptability or versatility
If an anti-reflection coating is used to adapt color appearance, then the color adaptability is improved, but different color appearances occur at different observation angles
Solution Approach 1:
The invention applies local quality by creating a gradient refractive index structure through the two-layer configuration. The first layer has higher refractive index (1.8-2.2) for thermal reflection, while the second layer has lower refractive index (1.3-1.7) for visible light anti-reflection. This local differentiation of optical properties at different interfaces eliminates angle-dependent color shifts while maintaining color adaptability.
Solution Approach 2:
The invention uses composite material structure with two layers of different refractive indices deposited on the substrate. This composite structure combines the reflection properties of the first layer with the anti-reflection properties of the second layer, achieving angle-independent uniform appearance while maintaining color adaptability through the electrochromic functional layer.
4Loss of energy
If the reflection layer thickness is increased to improve reflection, then the reflection performance is improved, but the external reflection color becomes dependent on observation angle
Solution Approach 1:
The second layer acts as an intermediary between the first reflection layer and the external environment. With refractive index 1.3-1.7, it serves as an optical buffer that eliminates interference effects and angle-dependent color shifts. This intermediary layer allows the first layer to provide strong thermal reflection while maintaining uniform visible appearance from all angles.
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 a simple, economical, and aesthetically pleasing uniform external reflection color that is independent of the switching state and observation angle, enhancing the appearance of buildings and vehicles with switchable glazings.
Implementation Method 1
a reflection layer on the outer surface and/or on the inner surface of the substrate
Implementation Method 2
the reflection layer contains a material having a refractive index nR from 1.6 to 2.55
Implementation Method 3
Electrochromic glazings that include an electrochemically active layer between two transparent flat electrodes are an example of this. The transmittance properties of the active layer can be electrically switched by the voltage applied to the flat electrodes.
Data Source
AI summary
A glazing having switchable optical properties is described, including a transparent substrate having an outer surface and an inner surface, a reflection layer on the outer surface and/or on the inner surface and a switchable functional element arranged on the interior side with respect to the reflection layer. The reflection layer contains a material having a refractive index nR of 1.6 to 2.5. The product of the refractive index nR and the thickness d of the reflection layer is from 250 nm to 960 nm.