Outdoor Lighting Spectrum Isolation for Low-Blue Warm White Light
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Solution Overview
Problem
Existing outdoor lighting systems disrupt circadian rhythms and ecosystems due to high scotopic-photopic ratios, blue light emission, and poor color quality, failing to achieve low sky glow, minimal circadian disruption, and efficient visual acuity.
Innovation Solution
An outdoor lighting system utilizing separate red and green LED sources, each with light converting materials, isolated to prevent excitation of the other, to minimize blue light emission and enhance visual acuity, with a power supply controlling modes for optimal light output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If cooler CCT LEDs (4000K to 6500K) are used for outdoor lighting, then energy efficiency and brightness are improved, but circadian disruption and ecosystem impact increase due to high blue light content
Solution Approach 1:
The patent segments the white light generation into separate red and green LED components with distinct phosphor converters, allowing independent spectral control. This segmentation enables the system to eliminate blue light while maintaining energy efficiency through optimized red (630-680nm) and green (520-560nm) wavelength emission that converts to warm white light without circadian-disruptive blue content
Solution Approach 2:
The patent changes the spectral parameters by using red LEDs (630-680nm peak) with red phosphor (K2SiF6:Mn4+) and green LEDs (520-560nm peak) with green phosphor (β-SiAlON:Eu2+), achieving warm white light (2000K-4000K) with zero or minimal blue light content, thereby resolving the contradiction between energy efficiency and circadian health
2Object-affected harmful factors
If phosphor amber lighting (1800K) is used to reduce blue light, then circadian disruption is minimized, but color quality and visual acuity deteriorate
Solution Approach 1:
The patent uses composite phosphor materials: red phosphor (K2SiF6:Mn4+) combined with green phosphor (β-SiAlON:Eu2+) in specific ratios to create a composite lighting system that achieves both low blue content (≤2% or zero) and high color quality (CRI≥80, R9≥90). This composite approach overcomes the limitations of single-phosphor amber lighting by combining the advantages of both red and green phosphors
Solution Approach 2:
The patent applies local quality by using different phosphor materials with specific emission characteristics in different proportions to achieve uniform warm white light with enhanced color rendering. The red phosphor provides deep red enhancement (R9≥90) while green phosphor fills the spectral gaps, creating localized spectral improvements that collectively deliver superior color quality without blue light
3Manufacturing precision
If higher CCT LEDs (2000K to 2400K) are used to improve color quality, then visual acuity is enhanced, but s/p ratio and sky glow increase
Solution Approach 1:
The patent segments the lighting spectrum into discrete red and green LED components with peak wavelengths of 630-680nm and 520-560nm respectively, eliminating the need for blue LEDs and their associated phosphor down-conversion that generates sky glow. This segmentation allows precise spectral control to achieve warm white light with CRI≥80 while maintaining s/p ratio <0.5 and zero or minimal blue light content
Solution Approach 2:
The patent changes the spectral parameters by using red LEDs (630-680nm peak) with red phosphor (K2SiF6:Mn4+) and green LEDs (520-560nm peak) with green phosphor (β-SiAlON:Eu2+), achieving warm white light (2000K-4000K) with zero or minimal blue light content, thereby resolving the contradiction between energy efficiency and circadian health
4Object-affected harmful factors
If separate red and green LED sources are used to minimize blue light, then circadian disruption is reduced, but device complexity increases
Solution Approach 1:
The patent merges the red LED module (with red phosphor) and green LED module (with green phosphor) into a single integrated outdoor lighting fixture, controlling both modules through a unified controller that regulates their relative intensities to produce warm white light. This merging approach reduces device complexity compared to using multiple separate fixtures while maintaining the spectral benefits of eliminating blue light content (≤2% or zero)
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 achieves sub-2% blue light fraction, high CRI, low s/p ratio, and adaptability, providing efficient lighting with minimal circadian and environmental impact.
Implementation Method 1
a first light source having at least one first LED and one or more first light converting materials for emitting said first light, said first light being a green light
Implementation Method 2
a second light source having at least one second LED and one or more second light converting materials for emitting said second light, said second light being a red light
Implementation Method 3
wherein said first light source and said second light source being isolated such that said first and second LEDs do not excite said second and first light converting materials, respectively
Data Source
AI summary
An outdoor lighting system for emitting emitted light, comprising: (a) a first light source having a first LED and first light converting material(s) for emitting said first light, said first light being a green light; (b) a second light source having a second LED and light converting material(s) for emitting said second light, said second light being a red light; (c) wherein said first light source and said second light source do not excite said second and first light converting material(s), respectively; and (d) a power supply for powering said first and second light sources to emit said first emitted light in a first mode, said first emitted light in having an overall SPD power and a blue SPD power, wherein said blue SPD power is no greater than 2% of said overall SPD power, said first emitted light being at least 0.005 Duv above the blackbody curve.