Waveguide Luminaire with Coupling Cavities for Asymmetric Lighting
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Solution Overview
Problem
Low-efficiency light coupling and distribution in LED-based luminaires due to the inherent losses when Lambertian emitting sources are coupled into the narrow edge of a waveguide plane, leading to inefficient illumination patterns, particularly in applications like roadway and parking lot lighting where targeted illumination is desired.
Innovation Solution
A luminaire design incorporating an optical waveguide with light coupling cavities and redirection features, where LEDs are positioned to direct light through a waveguide body with strategically placed extraction features, allowing for controlled light distribution and efficient extraction, achieving an asymmetric illumination pattern that minimizes longitudinal illumination while maximizing lateral illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If LEDs are coupled into the narrow edge of a waveguide plane, then light can be distributed across the waveguide, but light coupling efficiency is low due to Lambertian emission patterns
Solution Approach 1:
The waveguide structure is divided into distinct functional segments: a light coupling region with cavities for LED placement, a light distribution region with redirection features, and extraction regions. This segmentation allows optimization of light coupling efficiency in the coupling region while managing complexity through functional separation.
Solution Approach 2:
Light coupling cavities are introduced as intermediary structures between the Lambertian LED sources and the waveguide core. These cavities act as optical mediators that capture light from the LEDs and redirect it into the waveguide, improving coupling efficiency without requiring direct edge-coupling geometry.
2Adaptability or versatility
If light is distributed uniformly across the waveguide, then illumination coverage is maximized, but targeted illumination control is lost
Solution Approach 1:
The waveguide incorporates regions with different optical properties: some areas have extraction features for light removal, while other areas have redirection features for light transport. This local differentiation enables targeted illumination patterns where light is extracted only in specific zones, providing adaptability without sacrificing overall efficiency.
Solution Approach 2:
Light redirection features are pre-configured within the waveguide structure to guide light from the coupling region toward specific extraction zones before light naturally disperses. This preliminary directional control ensures that illumination is delivered efficiently to targeted areas rather than uniformly across the entire waveguide.
3Ease of operation
If extraction features are added to control light removal, then targeted illumination is achieved, but manufacturing complexity increases
Solution Approach 1:
The extraction features and redirection features are integrated into a single waveguide structure rather than being separate components. This merging reduces the number of assembly steps and allows for monolithic fabrication processes, easing manufacturing while maintaining the ability to control illumination patterns through the spatial distribution of features.
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 light extraction efficiency and distribution, providing a more targeted and efficient illumination pattern with improved optical efficiency and reduced glare, suitable for applications requiring specific lighting coverage.
Implementation Method 1
An optical waveguide mixes and directs light emitted by one or more light sources
Implementation Method 2
The extraction element(s) determine how light is removed by controlling where and in what direction the light exits the waveguide
Data Source
AI summary
A luminaire includes a housing, an optical waveguide disposed in the housing comprising a plurality of light coupling cavities, and a plurality of LEDs disposed in the housing adjacent the plurality of coupling cavities. A mounting apparatus is adapted to mount the luminaire on a roadway stanchion.