White Light Tuning With Duv Feedback for BBC Color Alignment
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Solution Overview
Problem
Existing lighting solutions struggle to accurately adjust white light tuning to align with the black-body radiation curve due to variations in CCT values among LEDs, leading to inconsistent color matching and deviations from the desired color temperature.
Innovation Solution
A lighting device incorporating warm and cool CCT LEDs, green light LEDs, and Duv adjustment LEDs, with controlled flux amounts determined by lookup tables, iteratively adjusts the Duv adjustment flux to minimize the departure of the combined light from the black-body radiation curve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a lookup table is used to control green light flux for white light tuning, then the process is simplified and faster, but the color matching precision deteriorates because the lookup table is based on ideal BBC curve assumptions that do not account for actual LED variations
Solution Approach 1:
The system measures the actual Duv value of the combined light and uses this feedback to adjust the green light flux. The controller compares the measured Duv with the target Duv (from BBC curve) and dynamically adjusts the green light flux accordingly, creating a closed-loop control system that adapts to actual LED variations and achieves precise color matching.
Solution Approach 2:
The system dynamically changes the green light flux parameter based on the measured Duv value and the corresponding lookup table entries. By adjusting the green light flux according to actual measurements rather than fixed ideal values, the system adapts to real LED characteristics and maintains precise color matching across different operating conditions.
2Ease of manufacture
If the green light flux is adjusted based on ideal BBC curve assumptions, then the lookup table can be pre-computed and stored, but the actual color temperature tuning accuracy deteriorates due to LED manufacturing variations
Solution Approach 1:
The lookup table is pre-computed and stored during the manufacturing phase, containing the relationship between green light flux and Duv values based on ideal BBC curve assumptions. This preliminary preparation simplifies the runtime operation, allowing the system to quickly adjust color temperature without complex real-time calculations.
Solution Approach 2:
The system uses actual measurements of the combined light's Duv value to feedback-adjust the green light flux. This feedback mechanism compensates for manufacturing variations in LEDs by adapting the lookup table values to actual operating conditions, thereby maintaining high color temperature tuning accuracy despite LED manufacturing tolerances.
3Adaptability or versatility
If multiple LEDs with different CCT values are combined for white light tuning, then the tuning range is expanded, but the color consistency deteriorates because each LED has different Duv values deviating from the BBC curve
Solution Approach 1:
The system dynamically adjusts the green light flux parameter based on the measured Duv value of the combined light. By changing the green light flux according to actual color temperature measurements, the system compensates for the different Duv values of individual LEDs and maintains color consistency across the expanded tuning range.
Solution Approach 2:
The system measures the actual Duv value of the combined light from multiple LEDs with different CCT values and uses this feedback to adjust the green light flux accordingly. This closed-loop control ensures that color consistency is maintained even when combining LEDs with varying characteristics, as the system adapts to the actual color temperature achieved.
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 effectively aligns the combined light's color temperature with the black-body radiation curve, ensuring precise white light tuning and consistent color matching across varying LED CCT values.
Implementation Method 1
warm CCT light emitting diodes (LEDs) configured to emit a warm white light having a warm CCT value and cool CCT LEDs configured to emit a cool white light having a cool CCT value
Implementation Method 2
green light LEDs configured to emit a green light having a green light flux
Data Source
AI summary
A lighting device includes warm Correlated Color Temperature (CCT) light emitting diodes (LEDs) configured to emit a warm white light and cool CCT LEDs configured to emit a cool white light. The lighting device further includes green light LEDs configured to emit a green light having a green light flux controlled based on a flux of the cool white light or a flux of the warm white light, where values corresponding to the green light flux are obtained from a lookup table. The lighting device further includes delta u,v (Duv) adjustment LEDs configured to emit a Duy adjustment light having an adjustment total flux that includes an adjustment flux amount having a maximum flux value determined by iteratively adjusting the adjustment flux amount until a Duy of a combined light that includes the warm white light and the Duy adjustment light is less than a threshold value.