LED Fixture Reflector Layout for Uniform Selectable Chromaticity

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Solution Overview

Problem

Existing LED lighting fixtures for theater, architectural, and television applications struggle to project high-intensity beams of light with selectable and uniform chromaticity, as they either require complex and expensive structures or are limited to projecting white light without discussing chromaticity uniformity.

Innovation Solution

The lighting fixture employs an arrangement of LEDs in separate columns emitting different dominant wavelengths, combined with a concave reflector having specific facets and an optical diffuser to ensure a projected beam with uniform chromaticity within a MacAdam ellipse of size 6X or less, using a heat pipe assembly for heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If incandescent lamps are used in traditional lighting fixtures, then high-intensity beams of light can be projected, but energy consumption is excessive and lamp lifetime is short

Engineering Contradiction:
Improvebeam intensityVSAvoidenergy consumption
Core Design Contradiction:
Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The patent changes the fundamental light generation mechanism from thermal radiation (incandescent) to electroluminescence (LED), representing a parameter change in the physical process. This substitution maintains high beam intensity while dramatically reducing energy consumption and extending operational lifetime, as LEDs are inherently more efficient light sources that convert electrical energy directly to light without excessive heat generation.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If LEDs emitting light in different wavelength bands are used to achieve selectable chromaticity, then color selection is possible, but chromaticity uniformity across the beam becomes difficult to control

Engineering Contradiction:
Improvechromaticity selectionVSAvoidchromaticity uniformity
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent segments the LED light source into multiple independent wavelength bands (e.g., red, green, blue LEDs), with each band controllable by separate signal channels. This segmentation allows independent adjustment of each wavelength component to achieve desired chromaticity while maintaining uniformity across the beam, as each segment can be optimized individually before combining into the final output.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by positioning LEDs of different wavelengths at specific locations within the light source assembly, with each LED or LED group having optimized characteristics for its intended wavelength band. This local optimization ensures that each portion of the beam contributes appropriately to the overall chromaticity uniformity, allowing precise control over color distribution across the entire beam profile.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If complex structures are used to achieve uniform chromaticity, then chromaticity uniformity can be improved, but device complexity and cost increase

Engineering Contradiction:
Improvechromaticity uniformityVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent achieves chromaticity uniformity through a simplified universal approach by using multiple LED types with inherently different spectral characteristics that can be independently controlled. Rather than adding complex optical components to mix and homogenize light, the system uses the natural emission properties of different LEDs combined with electronic control to achieve uniform chromaticity, reducing structural complexity while maintaining precision.

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

The solution achieves a high-intensity beam with selectable chromaticity variation within a MacAdam ellipse of size 6X or less, providing efficient energy use and reduced maintenance needs.

Implementation Method 1

Excess heat generated by the LED assemblies is conducted rearward along the heat pipe assembly to the heat sink, for dissipation

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

an elongated heat pipe assembly having a rearward end connected to the heat sink and a forward end that mounts the three or more LED assemblies

Methodology Applied
Scientific EffectHeat pipe effect: Heat Pipe

Implementation Method 3

light emitted from the three or more LED assemblies is reflected forwardly by the concave reflector

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 4

the lens assembly images the light passing through the gate at an area to be illuminated

Methodology Applied
Scientific EffectLight refraction and focusing: Lens

Data Source

PatentEP4190127B1Led-based lighting fixture providing a selectable chromaticity
Publication Date: 2025.12.31 CUNNINGHAM DAVID W
  • EP4190127B1 patent drawingFigure 1
  • EP4190127B1 patent drawingFigure 2A~2B
  • EP4190127B1 patent drawingFigure 3A~3B

AI summary

The disclosed invention is embodied in an improved LED-based lighting fixture for projecting a beam of light having a substantially uniform intensity, rotationally, and a selectable, substantially uniform chromaticity. The lighting fixture includes (1) a concave reflector having circumferential facets, a focal region, an aperture, and a central opening; and (2) a light source assembly including two or more groups of LEDs mounted at the forward end of an elongated, thermally conductive support. The light source assembly is mounted relative to the reflector with the elongated support's longitudinal axis aligned with the reflector's longitudinal axis and with the groups of LEDs located at or near the reflector's focal region. Each of the two or more groups of LEDs includes a plurality of LEDs arranged in two or more columns substantially parallel with the light source axis, with each column including only LEDs configured to emit light in a limited range of the visible spectrum and having the same distinct dominant wavelength, and with each group of LEDs including LEDs configured to emit light in two or more dominant wavelengths. The two or more groups of LEDs are configured to cooperate with the faceted concave reflector to project a beam of light having a selectable, substantially uniform chromaticity.