LED Package Backlit Waveguide Light Mixing
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Solution Overview
Problem
Low-efficiency light coupling and non-uniform color distribution in LED-based luminaires due to the use of predominantly Lambertian emitting sources and the edge-lit approach, which results in losses when light is directed into a narrow waveguide plane.
Innovation Solution
A luminaire design incorporating a back-lit approach with a waveguide body featuring a coupling cavity and a plug member with a reflective surface, along with extraction features and a primary optic that includes protrusions for light mixing, ensuring efficient light coupling and uniform color distribution by redirecting light through refraction and total internal reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a predominantly Lambertian emitting LED source is used with an edge-lit waveguide approach, then the luminaire structure is simplified, but light coupling efficiency deteriorates and losses occur when light is directed into the narrow waveguide plane
Solution Approach 1:
The patent inverts the conventional edge-lit approach by using back-lit LEDs positioned behind the waveguide. Instead of directing light from the side into the waveguide plane, light is directed from behind through the waveguide body, fundamentally changing the light coupling geometry to improve efficiency while maintaining structural simplicity
Solution Approach 2:
The patent modifies the waveguide body with extraction features (prisms, gratings, or roughened surfaces) that change the optical parameters of light propagation. These features enable efficient light extraction from the back-lit approach by controlling total internal reflection and refraction, thereby improving light coupling efficiency without complicating the overall structure
2Adaptability or versatility
If multiple LEDs of different colors are used, then color mixing capability is improved, but color uniformity deteriorates due to non-uniform distribution of light from different LED sources
Solution Approach 1:
The patent combines multiple LEDs of different colors (red, green, blue, yellow) into a single integrated LED assembly positioned behind the waveguide. This merging approach ensures that all color sources are equidistant from the waveguide surface, enabling uniform color distribution while maintaining versatile color mixing capability
Solution Approach 2:
The patent positions different colored LEDs at specific locations behind the waveguide surface, with each LED type strategically placed to optimize color distribution. The extraction features on the waveguide are also locally optimized to ensure uniform extraction of light from all color sources, achieving both color versatility and uniformity
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 mixing and extraction efficiency, achieving high overall system efficiency and uniform luminance with improved color mixing and intensity distribution, suitable for various lighting applications.
Implementation Method 1
redirecting light through refraction and total internal reflection
Implementation Method 2
redirecting light through refraction and total internal reflection
Implementation Method 3
a primary optic disposed adjacent the LEDs and including protrusions for mixing light developed by the plurality of LEDs
Implementation Method 4
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
According to one aspect, an LED package comprises a plurality of LEDs and a primary optic disposed adjacent the LEDs wherein the primary optic includes protrusions for mixing light developed by the plurality of LEDs.