Light-Redirecting Optical Daylighting System for Glazing
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Solution Overview
Problem
Existing daylighting systems face issues such as glare, uneven distribution of light, and excessive reliance on electric lighting due to the incident angle modifier effect, which reduces available daylight in interior environments and creates visual discomfort and energy inefficiencies.
Innovation Solution
A light-redirecting optical system with an outward-facing collection optic and inward-facing distribution optic, applied to glazing surfaces, redirects daylight to minimize glare and ensure uniform illumination by directing specular rays above the horizon, regardless of incidence angles between 5° and 85°, using a combination of transparent and translucent surfaces with specific geometric configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional fenestration glazing is used to transmit daylight, then the building interior receives natural light, but glare and high contrast ratios from direct sun rays cause visual discomfort
Solution Approach 1:
The glazing surface is segmented into multiple micro-prismatic structures with different orientations. Each prism segment redirects light in specific directions, collectively distributing daylight uniformly while blocking direct sun rays that cause glare. The segmentation allows the system to maintain high daylight transmission while eliminating harmful direct illumination.
Solution Approach 2:
Different regions of the glazing surface have locally optimized prism configurations tailored to specific directional requirements. The micro-prismatic structures are designed with varying angles and orientations to redirect light from different parts of the sky dome, creating uniform illumination across the interior while specifically targeting and eliminating glare sources.
2Illumination intensity
If fenestration glazing redirects daylight to improve distribution, then uniform illumination is achieved, but the incident angle modifier effect reduces the amount of available daylight entering the interior
Solution Approach 1:
The micro-prismatic structures perform multiple functions simultaneously: they redirect light for uniform distribution, maintain high transmittance across various incident angles, and control glare. The universal design of the prism geometry allows it to effectively handle light from different angles and directions, achieving uniform illumination without sacrificing the total amount of daylight entering the space.
Solution Approach 2:
The optical parameters of the glazing system are changed by introducing micro-prismatic structures with specific refractive indices and geometric configurations. These parameter changes enable the system to redirect light effectively while maintaining high transmittance, overcoming the incident angle modifier effect that typically reduces daylight availability in conventional glazing systems.
3Illumination intensity
If micro-optical structures are applied to fenestration glazing to redirect daylight, then the quality of light in the space is improved, but the system complexity and manufacturing difficulty increase
Solution Approach 1:
The micro-prismatic structures are fabricated as thin film coatings applied to the glazing surface, rather than bulky three-dimensional structures. This thin-film approach maintains the optical performance benefits of micro-optical structures while dramatically reducing manufacturing complexity, material usage, and application difficulty. The flexible film can be applied to existing glazing without requiring complex assembly procedures.
Solution Approach 2:
The complex mechanical micro-optical structures are replaced with optically equivalent thin-film patterns that achieve the same light redirection function through refractive index variations and geometric patterning. This substitution eliminates the need for precise mechanical assembly and bonding of complex three-dimensional structures, simplifying manufacturing while preserving the quality of daylight distribution.
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 system effectively reduces glare, ensures uniform lighting distribution, and maximizes the use of natural daylight, minimizing the need for electric lighting and enhancing occupant comfort and energy efficiency.
Implementation Method 1
The collection optic gathers incoming rays of the sun and redirects them inward
Implementation Method 2
redirects it inward to a distribution optic... redirects it into the interior environment
Implementation Method 3
The translucent portion projects directly away from the transparent portion toward the vertical surface of the glazing
Data Source
AI summary
Light-redirecting optical system for building fenestrations, such as glass doors and windows, storefront glazing systems, and curtain walls, that can collect and redirect daylight into the interior of a building. The light-redirecting optical system includes an outward-facing light-redirecting optical surface and an inward-facing light-redirecting surface. The outward-facing light-redirecting optical surface collects and redirects daylight mostly upward toward the inward-facing light-redirecting surface. The inward-facing light-redirecting surface receives the redirected daylight and further redirects it into the interior environment at pre-determined angles; so that all specular rays of light are at or above the horizon for a wide range of incident angles of daylight striking the outward-facing light-redirecting optical surface. The light-redirecting optical surfaces can be fabricated on a film or flexible substrate that may be directly applied to glass, acrylic, or other glazing surfaces. Alternatively, the light-redirecting optical surfaces may be fabricated directly on the glazing surfaces.