LED Luminaire Redirection Shield Asymmetric Light Control
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Solution Overview
Problem
Existing LED luminaires struggle to achieve uniform illumination over a wide target area while selectively reducing or eliminating light in specific adjacent areas, such as adjacent homes, due to the Lambertian light distribution pattern and the limitations of secondary lenses in redirecting light effectively.
Innovation Solution
An LED luminaire with a redirection shield featuring a base plate with apertures and shielding plates that block or redirect light output, allowing for asymmetric light distribution by positioning the shielding plates closer to certain LEDs to absorb or reflect light in specific directions, thereby reducing illumination in undesired areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If secondary lenses are used to uniformly redistribute light, then illumination uniformity in the target area is improved, but the ability to selectively exclude light from specific adjacent areas (e.g., homes) is worsened
Solution Approach 1:
The luminaire is divided into multiple independent LED modules, each with its own asymmetric secondary lens. This segmentation allows different portions of the light distribution to be controlled independently, enabling uniform illumination in the target area while selectively excluding light from specific adjacent areas like homes.
Solution Approach 2:
Asymmetric secondary lenses are used that have different optical properties in different directions. Each lens is designed with specific asymmetric characteristics to redirect light away from sensitive areas (e.g., homes) while maintaining uniform distribution in the target illumination area. This local quality variation allows simultaneous achievement of uniformity and selective exclusion.
2Adaptability or versatility
If asymmetric secondary lenses are used to redirect light away from adjacent areas, then light exclusion in specific directions is improved, but manufacturing complexity and cost are worsened
Solution Approach 1:
The system uses multiple identical or similar asymmetric lens modules rather than one complex custom lens. Each module can be manufactured using the same process, simplifying production while achieving the overall asymmetric light distribution pattern needed to exclude light from adjacent areas.
Solution Approach 2:
The asymmetric secondary lenses are designed to perform multiple functions: they redistribute light uniformly across the target area while simultaneously directing light away from sensitive areas. This multi-functionality reduces the need for additional specialized components, simplifying the overall system and reducing manufacturing complexity.
3Use of energy by moving object
If multiple LEDs are mounted on a flat surface facing downward, then light output quantity is improved, but hot spot formation directly under the luminaire is worsened
Solution Approach 1:
Asymmetric secondary lenses are employed that have directionally varying optical properties. These lenses are designed to reduce light intensity in the direction directly below the luminaire (where the hot spot would form) while maintaining or enhancing light distribution in lateral directions toward the target area. This local quality variation in the optical properties prevents hot spot formation while preserving overall light output quantity.
Solution Approach 2:
Instead of allowing the natural Lambertian distribution to direct maximum light downward (creating a hot spot), the asymmetric secondary lenses invert this pattern by redirecting light laterally away from the area directly below the luminaire. This inversion of the natural light distribution pattern eliminates the hot spot while maintaining sufficient illumination in the target area.
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 enables efficient and reliable asymmetric light distribution, effectively reducing light in targeted areas without adversely affecting illumination in other regions, providing a customizable and cost-effective solution for applications like residential street lighting.
Implementation Method 1
The plurality of shielding plates block a portion of the light output such that an overall light distribution of the light output from the LED luminaire is asymmetric
Implementation Method 2
Secondary lenses mounted over the LEDs are often used to more uniformly redistribute the light emitted from the LEDs
Data Source
AI summary
An LED lamp that includes a housing forming an open cavity, a plurality of LEDs configured to produce a light output disposed in the cavity, a lens disposed over the LEDs for focusing and/or diffusing the light output, and a redirection shield disposed in the cavity. The redirection shield includes a base plate with a plurality of apertures formed therein, and a plurality of shielding plates extending from a top surface of the base plate. The LEDs extend through the apertures. The shielding plates block a portion of the light output such that an overall light distribution of the light output from the LED lamp is asymmetric.