Luminescent Compositions for LED White Light Conversion
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Solution Overview
Problem
Current LED lamps face challenges in providing white light across a range of correlated color temperatures (CCT) values while maintaining high efficiency, luminous flux, good color rendering, and color stability, particularly in controlling circadian energy performance and minimizing the detrimental effects of blue light exposure.
Innovation Solution
The use of compositions comprising a plurality of luminescent materials and a matrix material, configured to convert light from LEDs into white light with desirable spectral characteristics, by combining light from multiple LED strings with different peak emissions through recipient luminophoric mediums, which include luminescent materials such as BaMgAl10O17:Eu, Lu3Al5O12:Ce, and CaAlSiN3:Eu, to achieve specific color ranges and spectral power distributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple LEDs of different colors are combined to produce white light, then the intensity and color of white light can be adjusted, but the color rendering index (CRI) deteriorates due to gaps in spectral power distribution
Solution Approach 1:
The patent combines multiple LED types (red, green, blue LEDs) with luminescent materials (phosphors) in a single lighting device. The luminescent materials convert excess energy from LEDs into additional wavelengths, merging the spectral outputs to fill gaps and improve CRI while maintaining adjustable white light intensity.
Solution Approach 2:
The patent uses composite luminescent material systems comprising multiple phosphors with different emission characteristics. These composite materials are designed to work together with specific LED types to generate a more complete spectral power distribution, improving color rendering while allowing intensity control.
2Illumination intensity
If luminescent materials are used to convert LED light to other colors, then white light can be produced, but the spectral power distribution remains narrow and centered around peak wavelengths
Solution Approach 1:
The patent segments the lighting system into multiple independent LED types (red, green, blue) each with different peak wavelengths, rather than relying on a single LED type with phosphor conversion. This segmentation allows the system to cover a broader spectral range and produce white light with more versatile spectral characteristics.
3Productivity
If blue light intensity is increased for white light generation, then luminous flux improves, but circadian rhythm disruption and harmful effects increase
Solution Approach 1:
The patent applies local quality by using different LED types with different spectral characteristics in specific combinations. Red LEDs contribute to luminous flux without the circadian-disrupting properties of blue light, while green and blue LEDs provide complementary wavelengths. The luminescent materials further convert energy to specific wavelengths, creating a spatial and spectral distribution that maintains productivity while reducing harmful effects.
Solution Approach 2:
The patent changes the spectral parameters of the light source by combining multiple LED types with different peak wavelengths and using luminescent materials with specific emission characteristics. This allows the system to maintain high luminous flux while adjusting the spectral composition to reduce blue light content and its associated harmful effects on circadian rhythms.
4Adaptability or versatility
If LED lamps are designed to provide white light across a range of CCT values, then adaptability improves, but maintaining high efficiency and color stability becomes difficult
Solution Approach 1:
The patent implements dynamic control by independently adjusting the drive currents to different LED types (red, green, blue LEDs) and/or varying the excitation intensity to luminescent materials. This dynamic adjustment capability allows the system to maintain color stability across different CCT values by optimally balancing the contribution of each LED type and luminescent material to the overall spectral power distribution.
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
This approach enables the generation of white light with improved color rendering performance across a range of CCT values, enhancing circadian rhythm regulation and reducing the adverse effects of blue light exposure, while maintaining high efficiency and luminous flux.
Implementation Method 1
one or more luminescent materials such as phosphors to convert some of the light emitted by one or more LEDs to light of one or more other colors
Data Source
AI summary
Systems and methods to provide multiple channels of light to form a blended white light output, the systems and methods utilizing recipient luminophoric mediums to alter light provided by light emitting diodes. The predetermined blends of luminescent materials within the luminophoric mediums provide predetermined spectral power distributions in the white light output.