Microstructured Anisotropic Diffuser for Glare Reduction in IGUs
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Solution Overview
Problem
Insulated Glazing Units (IGUs) with integrated microoptical elements face issues with glare due to the redirection of sunlight, as a fraction of light is directed downwards, forming a solar column, which affects energy efficiency and user comfort.
Innovation Solution
A microstructured anisotropic diffuser layer is integrated into the IGU, comprising a transfer tape with a structured surface and a backfill layer, where the microstructured surface and adjacent layer have different refractive indices, effectively diffusing visible light and reducing glare by redirecting at least 80% of daylight upwards for input angles between 30° to 60°.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If microoptical elements are integrated into the IGU to redirect sunlight to the interior ceiling, then energy efficiency is improved by augmenting conventional interior lighting, but glare is generated due to downward redirection of light forming a solar column
Solution Approach 1:
The microoptical layer is segmented into distinct functional zones: a first region with microoptical elements for upward light redirection and a second region with an anisotropic diffuser for glare reduction. This segmentation allows each zone to perform its specific function optimally without interfering with the other, resolving the contradiction between energy efficiency and glare prevention.
Solution Approach 2:
Different regions of the IGU are assigned different optical properties: the first region has high directional reflectivity for ceiling illumination, while the second region has anisotropic diffusion properties to scatter downward light. This local differentiation of optical qualities enables simultaneous achievement of energy efficiency and glare reduction in different areas.
2Object-generated harmful factors
If a microstructured anisotropic diffuser layer is integrated to reduce glare, then visibility of the solar column is minimized, but device complexity increases due to additional layers and structures
Solution Approach 1:
The anisotropic diffuser is integrated directly into the IGU structure as a second region of the microoptical layer, merging the glare reduction function with the existing window assembly. This integration approach combines multiple functions (light redirection and glare reduction) into a single composite structure rather than adding separate external components.
Solution Approach 2:
The anisotropic diffuser region utilizes composite microstructured materials with specific refractive index properties to achieve glare reduction. The diffuser comprises multiple layers including a backfill layer and a microstructured surface layer, creating a composite optical structure that provides the desired anisotropic diffusion effect while maintaining a relatively compact design.
3Productivity
If the microoptical layer is designed to redirect at least 80% of daylight upwards for input angles between 30° to 60°, then daylight redirection efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The microoptical elements are designed with specific geometric parameters optimized for the target input angle range of 30° to 60°. By tailoring the shape, size, and orientation of the microoptical structures to match the typical solar angle range, the system achieves high redirection efficiency (≥80%) for the most relevant operating conditions without requiring extreme manufacturing precision across all possible 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 significantly reduces glare by minimizing the visibility of the solar column while maintaining high daylight redirection efficiency, enhancing both energy efficiency and user comfort in buildings.
Implementation Method 1
the layer has a refractive index that differs from the backfill layer, and the microstructured surface together with the layer disposed on at least a portion of the microstructured surface is an anisotropic diffuser
Implementation Method 2
the microstructured surface together with the layer adjacent the microstructured surface is an anisotropic diffuser adapted to anisotropically diffuse visible light
Data Source
AI summary
Microoptical layers, glazing units including the microoptical layers, and transfer tapes that may be used to provide the microoptical layers are provided. The transfer tape includes a removable template layer having a structured surface, a backfill layer having a first surface disposed on at least a portion of the structured surface of the template layer, and a microstructured surface opposite the structured surface. The microstructured surface together with a layer disposed on the microstructured surface is an anisotropic diffuser.