Asymmetric Optic for Uniform LED Beam
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Solution Overview
Problem
Conventional rotationally symmetric optics fail to produce a uniformly rotationally symmetrical radiation pattern when used with non-rotationally symmetric light-emitting diodes (LEDs), leading to non-uniform light distribution in applications like backlights and luminaires, which requires high density and increased cost.
Innovation Solution
A non-rotationally symmetric optic is designed to collect and project a rotationally symmetric radiation pattern by using a wide-emitting lens with a non-rotationally symmetric shape, including a body, dimple, and inner cavity, to accommodate the LED and correct its asymmetric emission, resulting in a uniform output beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a rotationally symmetric secondary lens is placed on top of LEDs, then the lens can collect and project light, but the resulting radiation pattern is not completely rotationally symmetrical leading to non-uniform light distribution
Solution Approach 1:
The patent applies asymmetry by using a non-rotationally symmetric optic with specifically tailored surface profiles that have different curvatures in different radial directions. This asymmetric optic design compensates for the asymmetric emission characteristics of the LED, transforming the non-uniform radiation pattern into a uniform circular beam pattern.
Solution Approach 2:
The patent implements local quality by varying the optical properties at different locations on the optic surface. The optic features different surface curvatures and refractive indices in different radial directions, allowing each region to correct the specific asymmetric emission characteristics of the LED in that direction.
2Ease of manufacture
If conventional rotationally symmetric optics are used with non-rotationally symmetric LEDs, then the optical system is simple to manufacture, but the light distribution becomes non-uniform requiring high density of light sources
Solution Approach 1:
The patent uses asymmetric optic design to achieve uniform light distribution, which allows for increased spacing between LED sources while maintaining uniformity. This resolves the contradiction by showing that asymmetric optics can achieve both good manufacturing feasibility and improved productivity through reduced source density requirements.
3Illumination intensity
If a non-rotationally symmetric optic is used to correct asymmetric LED emission, then uniform rotationally symmetric beam pattern is achieved, but the optic design becomes more complex
Solution Approach 1:
The patent manages design complexity by implementing local quality variations in the optic - different surface curvatures and refractive properties at different radial positions. This allows the optic to correct asymmetric LED emission and produce uniform circular beams while maintaining a manageable design through systematic variation of local optical properties.
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 achieves a rotationally symmetrical output beam with improved uniformity, allowing for increased spacing between light sources and reducing costs by maintaining uniform light distribution across the emitting surface.
Implementation Method 1
The optic collects the first radiation pattern and projects a second radiation pattern that is rotationally symmetric
Data Source
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AI summary
A light source includes a light-emitting diode or device (LED) and an optic mounted over the LED. The LED emits a first radiation pattern that is non-rotationally symmetric about a first axis. The optic collects the first radiation pattern and projects a second radiation pattern that is rotational symmetric about a second axis and has a peak intensity that is angled from the second axis.