LED Homogenization via Dichroic Filters and Fly-Eye Lens
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Solution Overview
Problem
Existing LED luminaire systems struggle to achieve homogenization of light output when using four or more different colors of LEDs, resulting in objectionable spill light and color fringing due to physical separation and differing optical effects of lenses.
Innovation Solution
The use of dichroic filters, specifically designed to selectively transmit and reflect specific wavelength ranges, is employed to combine and homogenize the light from arrays of LEDs with discrete peak wavelengths, allowing for the integration of multiple colors into a single output beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple colors of LEDs are arranged in an array with physical separation, then the ability to create desired colors through mixing is improved, but color fringing and spill light occur due to physical separation and differing die sizes
Solution Approach 1:
A fly-eye lens pair is introduced as an intermediary optical element between the LED array and the focusing lens. This lens pair with varying optical densities acts as a mediator to redistribute and homogenize the light from different colored LEDs, eliminating color fringing and spill light while preserving the color mixing capability of the multi-color LED array.
2Ease of operation
If lenses are used to control beam shape and angle for each LED, then beam control is improved, but color fringing and aberrations occur due to differing optical effects for different colors
Solution Approach 1:
The fly-eye lens pair serves as an intermediary that corrects the chromatic aberrations and color fringing introduced by the individual LED lenses. By positioning this lens pair between the LED array and the focusing lens, the system maintains beam control capability while eliminating the color-specific optical aberrations.
3Adaptability or versatility
If dichroic reflecting filters are used to combine three single colors of LED into a beam, then color combination is improved, but homogenization of more than three colors is not achieved
Solution Approach 1:
The fly-eye lens pair acts as a universal intermediary that works effectively regardless of the number of LED colors (three or more). Unlike dichroic filters that are limited to specific wavelength combinations, the fly-eye lens pair homogenizes light from any number of colored LEDs by redistributing the light paths, achieving uniform color mixing for four or more colors.
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 approach effectively reduces color fringing and improves color uniformity by ensuring that only desired wavelengths pass through or are reflected, resulting in a more homogeneous and uniform light output across the combined beam.
Implementation Method 1
The use of dichroic filters, specifically designed to selectively transmit and reflect specific wavelength ranges, is employed to combine and homogenize the light from arrays of LEDs with discrete peak wavelengths
Data Source
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AI summary
An improved color LED homogenization system for LED luminaires employing a plurality of LED arrays where an array employs a plurality of discrete peak LED groups and dichroic mirrors maximized for transmission/reflection of around the groups of LED?s discrete peaks to generate a directional homogenized color light beam.