LED Luminaire Homogenization via Dichroic Beam Combining

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Solution Overview

Problem

Current LED luminaire systems struggle to effectively homogenize light output from arrays comprising four or more different colors of LEDs, leading to issues like spill light and color fringing due to physical separation and varying optical effects of lenses or dichroic filters.

Innovation Solution

The implementation of a system with three arrays of LEDs, each emitting light of different colors, where dichroic filters selectively transmit and reflect wavelengths to combine red, amber, blue, cyan, green, and yellow LEDs into a single homogenized beam, maintaining parallel optical axes and allowing independent intensity control of each zone within the arrays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple colors of LEDs are arranged in an array with physical separation, then the gamut of colors available is enhanced, but color fringing and spill light occur due to differences in die size and placement

Engineering Contradiction:
Improvegamut of colorsVSAvoidcolor fringing and spill light
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The LED array is divided into multiple independently controllable zones, each containing LEDs of different colors. This segmentation allows precise control of light from each zone to eliminate color fringing and spill light while maintaining the ability to produce a wide gamut of colors through selective activation and intensity control of individual zones.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each zone in the LED array is equipped with its own optical device (lens or reflector) tailored to that specific zone's requirements. This local optimization ensures that each zone's light output is precisely controlled to achieve uniform color mixing and eliminate harmful effects like color fringing, while the overall system maintains enhanced color gamut through the combination of multiple colored LEDs.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If lenses or optical devices are used in front of each LED to control beam shape, then the angle of output beam is controlled, but color fringing and aberrations become visible due to differing effects on different colors

Engineering Contradiction:
Improvebeam shape controlVSAvoidcolor fringing and aberrations
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The optical control system is segmented into multiple zones, each with its own optical device. This allows independent optimization of each zone's beam characteristics while maintaining overall beam uniformity. The segmentation enables precise control of beam shape for each color group without the color fringing that occurs when a single optical device attempts to control all colors simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each zone is equipped with an optical device specifically optimized for that zone's LED colors and positioning. This local quality approach ensures that each optical device is tuned to minimize chromatic aberrations and color fringing for its specific set of LEDs, while the collective arrangement of all zones produces a uniform, well-controlled output beam with enhanced color gamut.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If dichroic reflecting filters are used to combine three single colors of LED into a beam, then color mixing is achieved, but the system cannot mix more than three colors of LEDs

Engineering Contradiction:
Improvecolor mixing capabilityVSAvoidsystem limitation to three colors
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The LED array is divided into multiple zones, each containing a specific subset of colored LEDs. This segmentation allows the system to handle more than three colors by distributing different color combinations across different zones. Each zone can be independently controlled to produce specific colors, and the combination of all zones achieves a broader color gamut that exceeds the three-color limitation of traditional dichroic filter systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a universal LED array system that can produce a wide gamut of colors using more than three LED colors. By arranging multiple colored LEDs in independently controllable zones and using zone-specific optical devices, the system achieves multi-functionality, capable of producing any color within an expanded gamut while avoiding the three-color limitation of conventional dichroic filter-based systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 achieves improved homogenization of multiple LED colors, reducing spill light and color fringing, and enabling the creation of a wide range of colors with enhanced gamut, resulting in a more uniform and consistent light output.

Implementation Method 1

dichroic filters selectively transmit and reflect wavelengths to combine red, amber, blue, cyan, green, and yellow LEDs into a single homogenized light beam

Methodology Applied
Scientific EffectDichroic filter: Dichroic Filter

Data Source

PatentEP3715704B1Homogenization system for an LED luminaire
Publication Date: 2021.11.10 ROBE LIGHTING SRO
  • EP3715704B1 patent drawingFigure 1
  • EP3715704B1 patent drawingFigure 2
  • EP3715704B1 patent drawingFigure 3

AI summary

A luminaire and light source are provided. The light source includes first (20), second (30), and third (30) arrays of light emitting diodes (LEDs) and a beam combiner (52, 54). The LEDs of the first (10), second (20), and third (30) arrays of LEDs emit beams whose optical axes are substantially parallel. Each of the first (10) and second (20) arrays of LEDs produce light of two colors. The third array (30) of LEDs produces light of a single color. Each of the arrays of LEDs includes a plurality of zones, each zone spatially separated from other zones. Each zone of the first (10) and second (20) arrays includes LEDs of two colors. The intensities of the LEDs of each zone are controlled independently from the LEDs of other zones. The beam combiner (52, 54) combines light beams from all three arrays (10, 20, 30) of LEDs and produces an emitted beam of light (56) and maintains the optical axes of the light beams as substantially parallel to each other in the emitted beam of light (56).