Multi-Emitter LED Dimming for Higher Chroma at Low Light
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Solution Overview
Problem
Conventional light sources experience a muted color perception when dimmed, known as the Hunt Effect, which reduces the vibrancy and saturation of objects being illuminated, a phenomenon that existing 'dim-to-warm' technologies fail to effectively counteract.
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 indices like IES TM-30-15 gamut and chroma shift to enhance color perception during dimming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the light source is dimmed to reduce lumen output, then energy consumption decreases, 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 (e.g., blue LED with peak at 450nm, green LED with peak at 530nm, red LED with peak at 630nm). Each emitter is independently controllable, allowing selective adjustment of their individual contributions to the overall light output. This segmentation enables the system to maintain color gamut by preserving the spectral balance among different wavelength components even when total lumen output is reduced.
Solution Approach 2:
The system dynamically changes the relative intensity parameters of individual LED emitters based on the desired dimming level. At lower overall brightness levels, the control algorithm adjusts the ratio of intensities among blue, green, and red emitters to compensate for the Hunt Effect. This parameter adjustment ensures that the spectral power distribution maintains appropriate balance, thereby preserving object chroma and color vibrancy even when total luminous flux is reduced to save energy.
2Power
If conventional dimming is applied to reduce total lumen output, then power consumption decreases, but color gamut and color perception quality worsen
Solution Approach 1:
The multi-LED system segments the light source into independently controllable emitters with distinct spectral roles. During dimming operations, the control system selectively adjusts the drive current to each LED type (blue, green, red) to maintain the spectral balance that defines color gamut. This segmented control prevents the uniform dimming that would otherwise reduce color saturation and vibrancy, thereby preserving color information quality while reducing overall power consumption.
Solution Approach 2:
The system employs dynamic control of individual LED emitter intensities based on the operating dimming level. Rather than applying a fixed dimming ratio to all emitters, the control algorithm dynamically adjusts the relative contributions of blue, green, and red LEDs to compensate for the Hunt Effect. This dynamic adjustment maintains optimal spectral distribution across different brightness levels, preserving color gamut information while enabling power reduction.
3Temperature
If 'dim-to-warm' technology is used to adjust correlated color temperature during dimming, then color temperature changes, but object chroma and color vibrancy do not improve and may worsen
Solution Approach 1:
The system segments the light source into multiple LED emitters with different spectral characteristics, including blue LED (peak 450nm), green LED (peak 530nm), and red LED (peak 630nm). This segmentation allows independent control of each emitter's intensity, enabling the system to maintain the spectral balance necessary for color gamut preservation. Unlike dim-to-warm technology that uniformly shifts color temperature, this segmented approach can selectively adjust individual wavelength components to counteract the Hunt Effect and maintain object chroma.
Solution Approach 2:
The system dynamically changes the intensity parameters of individual LED emitters to maintain color gamut during dimming. Rather than allowing correlated color temperature to shift as in dim-to-warm technology, the control algorithm adjusts the relative intensities of blue, green, and red LEDs to preserve the spectral power distribution that defines color vibrancy. This parameter control ensures that object chroma is maintained even at reduced overall brightness levels.
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 counteracts the Hunt Effect by increasing object chroma and maintaining color vibrancy even at lower light levels, ensuring that objects appear more vivid and saturated when the light source is dimmed.
Implementation Method 1
The device includes a first LED emitter having a first peak wavelength and a second LED emitter having a second peak wavelength
Implementation Method 2
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
Data Source
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.