LED Flicker Reduction via Phosphorescent Afterglow and Grouped Voltage Thresholds
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Solution Overview
Problem
AC drive light-emitting devices using LED elements experience flicker due to voltage level changes, as some LED elements are not lit at low voltage levels, leading to inconsistent light emission.
Innovation Solution
A light-emitting device structure with a substrate hosting multiple groups of blue LED elements, where a fluorescent layer and a phosphorescent layer are strategically positioned to receive light from different groups, and a control circuit manages voltage supply to ensure constant lighting across varying AC voltage levels, utilizing a combination of blue LED elements, fluorescent, and phosphorescent materials to minimize flicker and adjust chromaticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If AC power source voltage level changes, then LED elements can be driven with varying voltage, but light emission becomes inconsistent and flicker occurs at low voltage levels
Solution Approach 1:
The patent segments the LED elements into multiple groups (first group, second group, third group) with different threshold voltages. Each group is connected in series and activated at different voltage levels of the AC power source. This segmentation allows the system to adapt to varying voltage levels while maintaining continuous light emission, as each group activates when the voltage reaches its specific threshold, preventing flicker and ensuring consistent illumination across the full voltage range.
2Adaptability or versatility
If multiple LED element groups with different thresholds are used, then voltage level adaptability is improved, but device structure becomes more complex
Solution Approach 1:
The patent merges multiple LED element groups with different threshold characteristics into a single series circuit configuration. By combining these groups in series and connecting them to a common AC power source, the system achieves voltage level adaptability without requiring complex control circuits or switching mechanisms. The series connection naturally ensures that all groups are activated in sequence as voltage increases, simplifying the overall device structure while maintaining the ability to operate across varying voltage 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 reduces flicker and improves chromaticity by ensuring consistent light emission across voltage level changes, utilizing the afterglow of phosphorescent materials to cover non-light-emitting periods and enhance color mixing, resulting in a stable and high-quality light output.
Implementation Method 1
a fluorescent layer disposed to receive light from the first group of blue LED elements
Implementation Method 2
a phosphorescent layer disposed to receive light from the second group of blue LED elements
Data Source
AI summary
A light-emitting device includes a substrate including electrodes, a first group including a plurality of blue light-emitting diode elements that are disposed on the substrate and electrically connected to the electrodes, a second group including a plurality of blue light-emitting diode elements that are disposed on the substrate and electrically connected to the electrodes, a fluorescent layer disposed to receive light from the first group of blue light-emitting diode elements, and a phosphorescent layer disposed to receive light from the second group of blue light-emitting diode elements.