Multicolor LED Beacon Radial Light Coupling
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Solution Overview
Problem
Existing LED beacons with fresnel collimating lenses struggle to efficiently couple light from multiple LEDs to the collimating lens, especially when LEDs are arrayed around a post, leading to non-uniform illumination and reduced light output, particularly in multi-color configurations.
Innovation Solution
The use of a condensing, coupling lens, such as a meniscus lens, shifts the focus of the collimating lens radially outward to the location of the LEDs, ensuring uniform distribution of light over the fresnel collimating lens, allowing for efficient coupling of light from multiple LEDs of different colors, enabling the use of various lens diameters and heights with the same LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If multiple LEDs are arrayed around a post to dissipate heat, then heat dissipation is improved, but light coupling efficiency to the collimating lens deteriorates due to non-uniform illumination
Solution Approach 1:
A light diffusing member is introduced as an intermediary component between the LED array and the fresnel collimating lens. This diffusing member receives light from multiple LEDs arrayed around a post and redistributes it uniformly across the collimating lens surface, thereby maintaining effective light coupling despite the spatial separation required for heat dissipation
2Illumination intensity
If a light diffusing member is used to distribute LED light, then illumination uniformity is improved, but light intensity is reduced due to inefficient coupling
Solution Approach 1:
The light diffusing member serves as a mediator that simultaneously achieves uniform illumination distribution and maintains high light intensity by efficiently coupling light from the LED array to the collimating lens through controlled diffusion rather than scattering
Solution Approach 2:
The optical properties of the diffusing member are optimized to control the diffusion parameter, allowing uniform light distribution while minimizing intensity loss through precise control of light redirection angles and paths
3Illumination intensity
If lenses are used to direct light radially outwardly to a fresnel collimating lens, then light directionality is improved, but the design is limited to opposed LEDs along a central axis, reducing total light output
Solution Approach 1:
The LED array is segmented into multiple LEDs positioned around the post at various angular positions, with each LED having its own lens for directional control. This segmentation allows light from multiple independent sources to be combined and directed to the collimating lens, increasing total light output beyond what a single central LED could provide
Solution Approach 2:
The LED array is arranged in a two-dimensional circular pattern around the post rather than along a single linear axis. This dimensional change allows LEDs to be positioned at multiple angular positions while maintaining proper optical alignment with the collimating lens through the diffusing member, thereby increasing total light output
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 solution enhances the light output and optical efficiency of both single-color and multi-color LED beacons, providing intense illumination suitable for warning lights by utilizing nearly all LED illumination, even when illumination is non-uniform, and allows for selective color activation and pattern generation.
Implementation Method 1
The use of a condensing, coupling lens, such as a meniscus lens, shifts the focus of the collimating lens radially outward to the location of the LEDs, ensuring uniform distribution of light over the fresnel collimating lens
Implementation Method 2
Light beacons have been provided with fresnel collimating lenses which provide cylindrical beams from a light source located centrally in the collimating lens
Data Source
AI summary
An LED beacon has a plurality of LEDs for emitting light of the same or different colors mounting along an upright member within an optical system. To provide a beacon illuminating selectively in one or more colors, the plurality of LEDs are in different groups of two or more LEDs, at least one LED in each group being of a different color. Each group of LEDs are mounted together circumferentially spaced from each other around a central axis. Each of the LEDs when activated projects light there from through the optical system provided by a collimating lens and a condensing, coupling lens. The optical system provides enhanced illumination distributed in a cylindrical beam emanating from the collimating lens. By selectively activating LEDs of the same colors or different color at different times different sequences or patterns may be generated.