Luminaire Waveguide Light Extraction Efficiency
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Solution Overview
Problem
Low-efficiency light coupling from LEDs into waveguides in low-profile LED-based luminaires due to losses inherent in coupling light emitted from Lambertian sources into the narrow edge of a waveguide plane.
Innovation Solution
A luminaire design incorporating multiple waveguides with different light emission surfaces and extraction features, where the extraction features on each surface have distinct characteristics, and LED elements are optically coupled to an optical coupling feature, allowing for controlled light emission patterns by varying the electrical power supplied to the LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If light is coupled from Lambertian LED sources into the narrow edge of a waveguide plane, then the luminaire achieves a compact low-profile design, but light coupling efficiency is reduced due to inherent losses
Solution Approach 1:
The patent introduces a coupling element as an intermediary component between the LED light source and the waveguide. This coupling element optimizes the transition of light from the Lambertian source into the waveguide's narrow edge, reducing inherent coupling losses while maintaining the compact low-profile luminaire design.
Solution Approach 2:
The patent modifies optical parameters at the coupling interface by controlling the angular distribution and spatial spread of injected light. Through discrete coupling optics, the system adjusts refraction, total internal reflection, and surface/volume scattering parameters to maximize light transfer efficiency into the waveguide while preserving the compact form factor.
2Loss of energy
If discrete coupling optics are used to control light distribution, then light coupling efficiency and angular control are improved, but device complexity increases
Solution Approach 1:
The patent merges the coupling optic functionality directly into the waveguide structure itself, eliminating the need for separate discrete coupling elements. The waveguide is designed with integrated coupling features at its edge that perform both structural and optical coupling functions, thereby reducing device complexity while maintaining high light coupling efficiency and angular control.
Solution Approach 2:
The waveguide structure is designed to serve multiple functions simultaneously: it acts as both the light guiding medium and the coupling interface. The edge of the waveguide incorporates both the structural boundary and the optical coupling mechanism, allowing a single component to perform what would traditionally require separate elements, thus reducing overall system complexity.
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
This design enhances light extraction efficiency and allows for adjustable luminous intensity patterns, improving illuminance and luminance distribution while minimizing reflection and losses, enabling a compact and efficient lighting solution.
Implementation Method 1
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 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
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 4
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
A luminaire comprises at least one waveguide having a first region that emits a first luminous intensity pattern and a second region that emits a second luminous intensity pattern different from the first luminous intensity pattern. The luminaire further includes a plurality of LED elements and circuitry to control the plurality of LED elements to cause the luminaire to produce a selected one of a plurality of luminous intensity patterns.