Multi-Source Lighting Below Planckian Locus
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Solution Overview
Problem
Existing lighting systems with multiple light sources fail to provide aesthetically pleasing 'white' light that emulates incandescent illumination, as most light sources with color points on the Planckian-black-body locus are not perceived as white, and research suggests that light emissions below and away from this locus are more aesthetically pleasing.
Innovation Solution
A lighting system comprising a first, second, and third light source, each with a semiconductor light-emitting device and a lumiphor, configured to emit light with specific color points between certain correlated color temperatures, forming combined light emissions that remain below the Planckian-black-body locus, achieving a distance of 0.001 to 0.009 delta(uv) throughout a light brightening/dimming curve, with a color rendition index of at least 75.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light sources are positioned on the Planckian-black-body locus to achieve correlated color temperatures, then the light emissions are perceived as aesthetically pleasing white light, but the color points drift away from the desired locus during brightening/dimming operations
Solution Approach 1:
The lighting system divides the illumination task into multiple independent light sources, each emitting at a specific wavelength range (blue, cyan, green, yellow-green, yellow, orange, red). This segmentation allows precise control over the spectral composition and color point positioning, enabling the combined output to remain stable on the Planckian locus during dimming while maintaining aesthetic white light perception.
Solution Approach 2:
The system dynamically adjusts the intensity parameters of individual light sources with different spectral characteristics to compensate for color point drift. By changing the relative contributions of each wavelength component during brightening/dimming operations, the combined color point is maintained within 0.005 delta(uv) of the Planckian locus, resolving the instability issue while preserving aesthetic quality.
2Illumination intensity
If multiple light sources with different spectral power distributions are combined to maintain color points below the Planckian-black-body locus, then aesthetically pleasing white light is achieved, but the system complexity increases
Solution Approach 1:
The lighting system integrates multiple light sources with distinct spectral power distributions into a unified modular assembly. Each light source is positioned and controlled as part of a nested hierarchical structure, where individual emitters are coordinated through a central control system. This nesting approach manages the complexity of multiple sources while achieving the desired color rendering and aesthetic white light perception below the Planckian locus.
Solution Approach 2:
The combined lighting system performs multiple functions simultaneously: it generates aesthetically pleasing white light, maintains color points below the Planckian-black-body locus, provides stable color rendering (CRI ≥ 80), and enables independent control of multiple spectral components. This multi-functionality justifies the increased device complexity by delivering comprehensive performance that single-source systems cannot achieve.
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 system produces combined light emissions with consistent color points that are perceived as white, maintaining a high color rendition index and aesthetically pleasing throughout the brightening/dimming curve, effectively emulating incandescent light while avoiding the limitations of traditional lighting systems.
Implementation Method 1
a first lumiphor configured for converting light emissions of the first semiconductor light-emitting device having a first spectral power distribution into first light source emissions having another spectral power distribution
Data Source
AI summary
Lighting system including first-, second-, and third-light sources each having semiconductor light-emitting device. First source includes lumiphor; and is configured for emitting first light source emissions having first color point between isotherms of CCTs of about 4800K-2500K; and is located within about 0.006 delta(uv) away from Planckian—black-body locus of CIE 1931 XY chromaticity diagram. Second light source is configured for emitting second light source emissions having second color point between isotherms of CCTs of about 2900K-1700K. Third light source is configured for emitting third light source emissions having: third color point between line-of-purples and isotherm of CCT of about 1500K; and dominant- or peak-wavelength between about 590-700 nanometers. Lighting system is configured for forming combined light emissions and causing combined color points to remain below Planckian—black-body locus by about 0.001-0.009 delta(uv) throughout light brightening/dimming curve. Related processes.