Troffer Optical Assembly Heat Sink and Reflector Cavity
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Solution Overview
Problem
Troffer-style lighting fixtures face challenges in efficiently managing heat from high power LEDs and achieving uniform color mixing and optical efficiency, particularly in modern structures with limited plenum space and existing designs that often result in harsh surface luminance and optical losses.
Innovation Solution
The design incorporates an elongated heat sink with a mount surface, an elongated lens, and reflectors that define an interior cavity, along with a lens plate and a pan structure with an inner reflective surface, to efficiently dissipate heat and mix light from LEDs, using diffuse reflective materials to achieve uniform luminance and high optical efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional troffer designs are used with high power LEDs, then heat dissipation is achieved through plenum circulation, but optical efficiency is reduced due to harsh surface luminance and light loss
Solution Approach 1:
The fixture is divided into distinct functional zones: a first compartment for LED mounting with direct view optics, and a second compartment for diffuse reflection. This segmentation allows optimized light paths for each function, improving overall optical efficiency by preventing light loss at the transition zone between direct and diffuse viewing areas.
Solution Approach 2:
A transition zone with intermediate viewing characteristics is introduced between the direct view and diffuse reflection compartments. This intermediary region gradually transitions the luminance characteristics, reducing harsh contrasts and improving visual comfort while maintaining optical efficiency.
2Stability of the object's composition
If multiple LED packages are arranged to produce white light, then color uniformity is improved, but spatial color mixing becomes difficult due to shadow casting
Solution Approach 1:
The fixture separates LED packages into different compartments based on their optical function: direct view LEDs in the first compartment and diffuse reflection LEDs in the second compartment. This segmentation allows each group to be optimized for its specific purpose, improving color uniformity while avoiding the shadow casting problems that would occur with mixed arrangements.
Solution Approach 2:
The patent uses multiple LED packages with identical or similar spectral characteristics within each compartment to ensure consistent color output. By replicating the LED package design and arrangement pattern, the system achieves uniform color distribution across the lighting output.
3Temperature
If LEDs are mounted to dissipate heat into the plenum, then cooling is facilitated through air circulation, but modern ceiling designs with limited plenum space reduce heat dissipation effectiveness
Solution Approach 1:
The patent extracts the heat dissipation function from the plenum space and relocates it to the fixture structure itself through integrated heat sinks. This extraction allows the fixture to be self-cooling, eliminating dependence on plenum space and making it compatible with modern ceiling designs that have limited or no plenum access.
Solution Approach 2:
The fixture structure serves multiple functions simultaneously: it provides mechanical support for LEDs, directs light through optimized optical paths, and dissipates heat through integrated heat sinks. This multi-functionality eliminates the need for separate cooling infrastructure, making the fixture universally adaptable to various ceiling types including those with limited plenum space.
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 configuration provides a visually pleasing output with reduced surface luminance, improved color uniformity, and high luminous efficacy, achieving up to 88% total optical efficiency while minimizing heat management issues and glare, suitable for modern ceiling designs.
Implementation Method 1
elements of the troffer on the back side dissipate heat generated by the light source into the plenum where air can be circulated to facilitate the cooling mechanism
Implementation Method 2
An elongated heat sink comprises a mount surface for light sources
Implementation Method 3
using diffuse reflective materials to achieve uniform luminance and high optical efficiency
Implementation Method 4
When a bias is applied across the doped layers, holes and electrons are injected into the active region where they recombine to generate light
Implementation Method 5
The surrounding phosphor material 'downconverts' some of the blue light, changing it to yellow light
Data Source
AI summary
A troffer-style fixture. The fixture is particularly well-suited for use with solid state light sources. The troffer comprises a light engine unit surrounded by a reflective pan. An elongated heat sink comprises a mount surface for light sources. An elongated lens is mounted on or above the heat sink. The mount surface is designed to accommodate the light emitters which may come on prefabricated a light strip. One or more reflectors extend out away from the heat sink on the mount surface side. A lens plate is mounted to proximate to the heat sink and extends out to the edge of the reflector(s). An interior cavity is at least partially defined by the reflector(s), the lens plates, and the heat sink. One or more light sources disposed along the heat sink mount surface emit light into the interior cavity where it can be mixed and/or shaped before it is emitted.