Waveguide Plug Member for Uniform Light Distribution
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Solution Overview
Problem
Low-efficiency light coupling and non-uniform light distribution in LED-based luminaires due to the inherent characteristics of Lambertian emitting sources and the use of narrow edge waveguides, leading to losses and non-uniform color and intensity output.
Innovation Solution
A waveguide design incorporating a coupling cavity with a plug member and reflective surfaces to efficiently direct light into the waveguide, combined with light extraction features and internal redirection features to achieve uniform light mixing and distribution, using refractive interfaces and complex coupling cavity geometries to manage light refraction and extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If narrow edge waveguides are used in LED-based luminaires, then the luminaire can maintain a compact design, but light coupling efficiency decreases and light distribution becomes non-uniform
Solution Approach 1:
The waveguide is segmented into multiple sections with different geometries - a first section with a first cross-sectional dimension and a second section with a second cross-sectional dimension. This segmentation allows the light to be coupled into a narrower section while still achieving uniform distribution across a larger output area, thereby maintaining compact size while improving coupling efficiency and distribution uniformity.
Solution Approach 2:
Different sections of the waveguide are given different local qualities through varying cross-sectional dimensions. The first section has optimized dimensions for efficient light coupling from the LED source, while the second section has dimensions optimized for uniform light extraction. This local optimization resolves the contradiction between compact size and light distribution quality.
2Volume of moving object
If narrow edge waveguides are used in LED-based luminaires, then the luminaire can maintain a compact design, but light distribution uniformity deteriorates
Solution Approach 1:
The waveguide is divided into sections with different cross-sectional dimensions to separately optimize for compact coupling and uniform distribution. The segmented structure allows the light to transition from a focused coupling point to a distributed output pattern, achieving both compact size and uniform illumination.
Solution Approach 2:
The waveguide transitions from a narrow single-dimension coupling edge to a broader two-dimensional output face. By expanding in one dimension while maintaining compactness in other dimensions, the design achieves uniform light distribution across the output surface while keeping the overall luminaire compact.
3Ease of manufacture
If Lambertian emitting LED sources are used, then the light source is simple and cost-effective, but light coupling into the waveguide is inefficient
Solution Approach 1:
The waveguide's first section is specifically designed with optimized cross-sectional dimensions to match the Lambertian emission pattern of standard LED sources. This local optimization at the coupling interface maximizes light capture efficiency while allowing the use of simple, cost-effective Lambertian LED sources without requiring complex specialized light sources.
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
Enhances light mixing and uniformity, improving the overall efficiency and color consistency of the luminaire output while minimizing losses and maintaining a compact design.
Implementation Method 1
The second portion includes a reflective surface adapted to direct light in the coupling cavity into the waveguide body
Implementation Method 2
Discrete coupling optics use refraction, total internal reflection, and surface or volume scattering to control the distribution of light injected into the waveguide
Implementation Method 3
In accordance with well-known principles of total internal reflectance light traveling through a waveguide is reflected back into the waveguide from an outer surface thereof
Data Source
AI summary
According to one aspect, a waveguide comprises a waveguide body having a coupling cavity defined by a coupling feature disposed within the waveguide body. A plug member comprises a first portion disposed in the coupling cavity and an outer surface substantially conforming to the coupling feature and a second portion extending from the first portion into the coupling cavity. The second portion includes a reflective surface adapted to direct light in the coupling cavity into the waveguide body.