Waveguide Footprint Management for High Power Density
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Solution Overview
Problem
Existing optical waveguides face limitations in lumen output due to high lumen power density at the LED/waveguide coupling interface, leading to overheating issues and restricted footprint expansion, which restricts the expansion of waveguide designs and requires extensive heat exchanger mechanisms.
Innovation Solution
The waveguide design incorporates a light coupling portion with a similar or smaller footprint than the light emitting portion, featuring light extraction features such as indents, facets, or holes, and a light transmission portion that optically couples the light coupling portion to the light emitting portion, reducing lumen power density and minimizing heat buildup without increasing the waveguide's footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the waveguide footprint is increased to reduce lumen power density, then heat buildup is reduced, but the device size increases
Solution Approach 1:
The waveguide is divided into three distinct functional portions: a light coupling portion for receiving LED light, a light transmission portion for guiding light through total internal reflection, and a light emitting portion for extracting light. This segmentation allows each portion to be optimized independently, enabling compact overall design while managing heat effectively through specialized light extraction features in the emitting portion.
Solution Approach 2:
Light extraction features (such as facets, holes, or surface modifications) are applied locally to the light emitting portion rather than uniformly across the entire waveguide. This localized approach concentrates light extraction where needed while maintaining the compact footprint, as the features enable efficient light coupling without requiring extensive waveguide area expansion.
2Temperature
If extensive heat exchanger mechanisms are added to manage heat, then overheating is prevented, but device complexity increases
Solution Approach 1:
Heat management is achieved by extracting light efficiently at the light emitting portion through specialized extraction features, rather than relying on separate heat exchanger mechanisms. The optical design inherently manages thermal issues by optimizing light coupling and extraction, removing the need for complex thermal management subsystems.
3Productivity
If lumen power density is increased for higher output, then light output increases, but overheating occurs
Solution Approach 1:
The light emission characteristics are optimized locally at the light emitting portion through specific extraction features (facets, holes, surface modifications) that enhance light extraction efficiency. This localized optimization allows high lumen output to be achieved without proportionally increasing heat generation, as the features improve optical coupling efficiency.
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 distribution and reduces overheating, allowing for increased lumen output while maintaining a compact footprint, thereby overcoming the limitations of traditional waveguide designs.
Implementation Method 1
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, provided that the incident light does not exceed a critical angle with respect to the surface.
Implementation Method 2
The light extraction feature may comprise at least one of indents, depressions, facets or holes extending into the fourth surface. The light extraction feature may comprise at least one of bumps, facets or steps rising above the fourth surface.
Data Source
AI summary
A waveguide includes a light coupling portion has an interior surface and an exterior surface. The exterior surface includes light coupling features. LEDs emit light into the light coupling features. A light emitting portion has an interior surface and an exterior surface where the exterior surface defines a light emitting surface. The light emitting portion is disposed adjacent the light coupling portion. A light transmission portion optically couples the light coupling portion to the light emitting portion. A footprint of the light coupling portion is substantially the same or less than a footprint of the light emitting portion.