Multi-Channel White Light Tuning for Circadian and Color Rendering
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Solution Overview
Problem
Current LED lamps face challenges in providing white light with tunable circadian energy performance across a range of correlated color temperatures (CCT) while maintaining high efficiency, luminous flux, and good color rendering, and achieving acceptable color stability, especially in controlling circadian rhythm impacts.
Innovation Solution
The method involves combining light from blue, red, yellow/green, and cyan LED channels, with each channel emitting light through respective luminophoric mediums, allowing for independent drive current adjustments to produce white light within specific CCT ranges and circadian action factor thresholds, utilizing ultraviolet or violet LEDs and cyan LEDs to achieve desired color points on the 1931 CIE Chromaticity Diagram.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple LED channels (blue, red, yellow/green, cyan) are combined to achieve tunable CCT and circadian energy performance, then color rendering and circadian control are improved, but device complexity increases
Solution Approach 1:
The lighting device is divided into multiple independent LED channels (blue, red, yellow/green, cyan), each with its own drive current control. This segmentation allows independent adjustment of each channel's contribution to the overall spectral power distribution, enabling precise tuning of both CCT and circadian action factor while maintaining manageable complexity through modular architecture
Solution Approach 2:
The multi-channel LED system serves multiple functions simultaneously: it provides general illumination, achieves tunable correlated color temperature (CCT), controls circadian rhythm impacts through circadian action factor adjustment, and maintains high color rendering. The same hardware infrastructure supports all these functions through coordinated control of the four LED channels
2Measurement precision
If drive currents are independently adjusted for each LED channel to control CCT and circadian action factor, then precision of color and circadian control is improved, but ease of operation deteriorates
Solution Approach 1:
The control system incorporates feedback mechanisms that monitor the actual CCT and circadian action factor outputs and automatically adjust the drive currents to the four LED channels. This closed-loop control maintains high precision in achieving target values while shielding the user from the complexity of manual multi-parameter adjustment
Solution Approach 2:
The system transforms the complex task of independently controlling four drive currents into simpler parameter adjustments. By allowing users to specify desired CCT and circadian action factor values, the control system automatically calculates and applies the appropriate drive current combinations, converting high-dimensional control into low-dimensional user interaction
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 enables the generation of white light with precise CCT control and improved circadian energy performance, ensuring high color rendering indices and stability across various CCT values, effectively addressing the limitations of existing LED technologies.
Implementation Method 1
combining light from blue, red, yellow/green, and cyan LED channels, with each channel emitting light through respective luminophoric mediums
Implementation Method 2
each channel emitting light through 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. One or more of the LED strings can have ultraviolet or violet LEDs.