Tunable White Light LED Strings for Circadian Rhythm Control
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Solution Overview
Problem
Existing LED lamps face challenges in providing white light with tunable color temperature and circadian energy performance while maintaining high efficiency, luminous flux, and color rendering index, particularly in controlling circadian rhythm disruption caused by blue light exposure.
Innovation Solution
The method involves using LED strings with different peak wavelengths, such as blue, red, yellow/green, and cyan LEDs, combined with luminophoric mediums to produce white light that can be tuned across a range of color temperatures, ensuring high color rendering and circadian action factor values by varying drive currents and using specific luminescent materials to achieve desired spectral power distributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If blue light is used to achieve high luminous efficiency and long wavelength coverage, then luminous flux is improved, but circadian rhythm disruption increases
Solution Approach 1:
The patent segments the blue light emission into multiple wavelength components using separate LED chips (first blue LED at 440-470nm, second blue LED at 470-505nm) to independently control different portions of the blue spectrum. This allows selective enhancement of luminous flux while limiting the specific wavelengths that cause circadian disruption.
Solution Approach 2:
The patent applies local quality by using luminophoric materials with specific emission characteristics targeted at suppressing melatonin production. The luminophors are selected to emit at wavelengths that address circadian rhythm regulation while the LED combination provides the luminous flux, creating localized functional zones within the lighting system.
2Manufacturing precision
If multiple LED strings with different peak wavelengths are used to achieve high color rendering, then color rendering index is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple LED strings with different peak wavelengths (blue, cyan, yellow/green, red) into a unified lighting system. By combining these diverse light sources, the system achieves comprehensive spectral coverage for high color rendering while managing the complexity through integrated control architecture.
Solution Approach 2:
The patent implements multi-functionality by designing LED strings that serve dual purposes: each LED string not only contributes to overall luminous flux but also specifically targets certain spectral regions for color rendering enhancement. This universal approach allows each component to perform multiple functions simultaneously.
3Adaptability or versatility
If drive currents are varied to tune color temperature, then circadian energy performance is improved, but control complexity increases
Solution Approach 1:
The patent implements dynamics by enabling real-time adjustment of drive currents to individual LED strings based on desired color temperature and circadian performance targets. The system dynamically reconfigures the spectral output by varying current levels, allowing adaptation to different operational requirements while maintaining control through programmed algorithms.
4Manufacturing precision
If luminophoric materials are used to convert LED light to achieve desired spectral power distribution, then color rendering is improved, but efficiency losses increase
Solution Approach 1:
The patent applies parameter changes by selecting luminophoric materials with specific emission wavelengths and efficiency characteristics that minimize energy loss during conversion. By carefully choosing luminophors whose emission spectra align with the desired output and whose conversion efficiency is optimized, the system achieves improved color rendering while reducing the efficiency penalty associated with phosphor conversion.
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 allows for the generation of white light within a narrow color matching range of the 1931 CIE chromaticity diagram, providing improved color rendering and circadian performance across various color temperatures, reducing the adverse effects of blue light exposure on circadian rhythms.
Implementation Method 1
producing light from a first light emitting diode (LED) string, producing light from a second LED string, producing light from a third LED string, a fourth LED string
Implementation Method 2
passing the light produced by each of the first, second, third, and fourth LED strings through one of a plurality of respective luminophoric mediums
Data Source
AI summary
The present disclosure provides methods for generating tunable white light with controllable circadian energy performance. The methods use a plurality of LED strings to generate light with color points that fall within blue, yellow/green, red, and cyan color ranges, with each LED string being driven with a separately controllable drive current in order to tune the generated light output. Different light emitting modes can be selected that utilize different combinations of the plurality of LED strings in order to tune the generated white light.