Multi-Emitter LED Dimming for Higher Object Chroma
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Solution Overview
Problem
Conventional light sources experience a muted color perception when dimmed, known as the Hunt Effect, where objects appear less colorful at low light levels, which is undesirable in applications requiring vibrant color retention.
Innovation Solution
A method and device that independently control multiple LED emitters to increase the color gamut while decreasing lumen output, maintaining a constant correlated color temperature and adjusting the IES TM-30-15 gamut index and chroma shift to counteract the Hunt Effect, using a combination of red, amber, lime, green, cyan, blue, and royal blue emitters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the light source is dimmed to reduce lumen output, then energy consumption is reduced, but object chroma and color vibrancy deteriorate due to the Hunt Effect
Solution Approach 1:
The light source is divided into multiple LED emitters with different spectral characteristics (violet, blue, cyan, green, yellow-green, yellow, orange, red). Each emitter is independently controllable, allowing selective activation to maintain color gamut while reducing overall lumen output during dimming operations
Solution Approach 2:
The system dynamically adjusts the relative intensity parameters of each LED emitter based on the desired dimming level. By changing the emission parameters of individual emitters rather than uniformly reducing all emissions, the patent maintains optimal color rendering while achieving energy reduction
2Illumination intensity
If multiple LED emitters are independently controlled to increase color gamut during dimming, then object chroma is improved, but device complexity increases
Solution Approach 1:
The control circuit is designed to perform multiple functions: it manages independent emitter control for color gamut optimization, calculates and applies Hunt Effect compensation, and regulates overall lumen output. This multi-functionality reduces the need for separate dedicated circuits for each function
Solution Approach 2:
The system incorporates feedback mechanisms where the control circuit continuously monitors the output of each LED emitter and adjusts their intensities accordingly. This feedback loop enables automatic Hunt Effect compensation and maintains optimal color rendering without requiring complex manual intervention
3Stability of the object's composition
If the correlated color temperature is maintained constant during dimming, then color consistency is improved, but the ability to compensate for Hunt Effect deteriorates
Solution Approach 1:
The system dynamically adjusts the mix of different LED emitters based on the dimming level while maintaining a consistent correlated color temperature. By dynamically changing the relative contributions of each emitter type rather than using a static configuration, the patent achieves both color consistency and Hunt Effect compensation
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 increases object chroma during dimming, maintaining a high color gamut and fidelity index while reducing lumen output, ensuring vibrant color perception even at lower light levels.
Implementation Method 1
A method and device that independently control multiple LED emitters to increase the color gamut while decreasing lumen output
Implementation Method 2
using a combination of red, amber, lime, green, cyan, blue, and royal blue emitters
Data Source
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Figure 2A~2B
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AI summary
A method of increasing the color gamut of a multi-emitter light emitting device when dimming includes the steps of independently driving each emitter in the device, and increasing the lumen output of at least one emitter while simultaneously decreasing the lumen output of at least one other emitter, such that total color gamut increases while total lumen output of the light emitting device decreases. A light emitting device is also disclosed.