LED Lighting Device BBL Dimming via Segmented Wavelength Control
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Solution Overview
Problem
Existing LED-based lighting devices struggle to achieve the Black Body Locus (BBL) dimming effect without complex control algorithms and suffer from significant light output decrease at increased temperature, especially in high-brightness applications, and have a low Color Rendering Index (CRI) at certain color temperatures.
Innovation Solution
A lighting device comprising two sets of LEDs with independently controllable brightness levels, combined with luminescent elements that convert light to maintain a correlated color temperature (CCT) within the BBL range, allowing for simple dimming to achieve the BBL effect without complex control algorithms and improving CRI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If an amber LED light source is added to achieve the BBL dimming effect, then the color temperature can follow the BBL during dimming, but the device complexity increases due to requiring a complicated controller
Solution Approach 1:
The patent changes the spectral parameters by using LEDs with different dominant wavelengths (440-465nm and 465-490nm) instead of using amber LEDs. By independently controlling the brightness of these two LED sets, the system achieves BBL dimming effect through parameter variation rather than adding complex control logic for multiple LED types.
Solution Approach 2:
The patent segments the blue light spectrum into two distinct wavelength ranges (440-465nm and 465-490nm) with independently controllable LED sets. This segmentation allows each set to contribute differently to the overall color temperature during dimming, achieving the BBL effect through simplified independent control rather than complex integrated control.
2Stability of the object's composition
If the light output level of amber LED is increased during dimming, then the BBL dimming effect is achieved, but the light output shows a relative large decrease at increasing temperature
Solution Approach 1:
The patent uses LEDs with dominant wavelengths in the 440-490nm range instead of amber LEDs. These blue-violet LEDs maintain more stable light output characteristics at increased temperatures compared to amber LEDs, while still enabling BBL dimming effect through independent brightness control of the two LED sets.
3Stability of the object's composition
If the color temperature is reduced to approximately 2200K during dimming, then the BBL dimming effect is achieved, but the CRI of the generated light becomes relatively low
Solution Approach 1:
The patent maintains higher color temperatures (2700K-4000K range) by using blue-violet LED sets with dominant wavelengths of 440-465nm and 465-490nm, avoiding the need to drop to 2200K. This parameter choice preserves better CRI while still achieving the BBL dimming effect through independent control of the two LED sets.
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 enables the lighting device to maintain a CCT within the BBL range during dimming, providing a comfortable and accurate color rendering across various brightness levels, including high-brightness applications, without the need for intricate control systems.
Implementation Method 1
a first luminescent element radiationally coupled to the first and second set of light emitting diodes and arranged to convert at least a part of the light of the first wavelength range and at least a part of the light of the second wavelength range into first luminescent element light
Implementation Method 2
convert at least a part of the light of the first wavelength range and at least a part of the light of the second wavelength range into first luminescent element light
Data Source
AI summary
The invention provides a lighting device (100) comprising a first set of light emitting diodes (10) arranged to emit light (14) in a first wavelength range of 300 nm-490 nm, a second set of light emitting diodes (11) arranged to emit light (15) in a second wavelength range of 300 nm-490 nm, a first luminescent element (12) radiationally coupled to the first and second set of light emitting diodes and arranged to convert at least a part of the light of the first wavelength range and at least a part of the light of the second wavelength range into first luminescent element light, a second luminescent element (13) radiationally coupled to at least a subset of the second set of light emitting diodes and arranged to convert at least a part of the light (15) of the second wavelength range into second luminescent element light, wherein, during operation, the brightness level of the light (14) emitted by the first set of light emitting diodes (10) and the brightness level of the light (15) emitted by the second set of light emitting diodes (11), respectively, is controllable independently of each other and wherein the lighting device is arranged to generate white lighting device light (101).