Mn4+ Doped Complex Fluoride Phosphor for Red Light Conversion
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Solution Overview
Problem
The LED package industry faces challenges in achieving enhanced red light down-conversion from blue light sources while maintaining damage resistance to high optical flux, requiring improved phosphor performance and reliability.
Innovation Solution
The use of a Mn4+ doped complex fluoride phosphor with a specific particle size range (1-10 micrometers) in a phosphor-converted LED package, which includes a blend of encapsulant material and phosphor composition, enhances red phosphor conversion efficiency and reduces susceptibility to damage from high optical flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional phosphor materials are used for red light down-conversion, then the LED package can achieve basic red light emission, but the conversion efficiency is insufficient and damage resistance to high optical flux is poor
Solution Approach 1:
The patent changes the chemical composition parameters of the phosphor material by doping Mn4+ ions into complex fluoride host structures (e.g., K2SiF6, Rb2GeF6, Cs2TiF6). This compositional parameter change enables simultaneous achievement of high red light conversion efficiency and improved damage resistance to high optical flux, resolving the technical contradiction between conversion efficiency and reliability.
Solution Approach 2:
The patent employs composite phosphor materials consisting of Mn4+-doped complex fluoride structures combined with specific host materials. These composite materials exhibit enhanced performance where the Mn4+ dopant provides efficient red emission while the complex fluoride host structure provides high damage resistance, thereby resolving the contradiction between conversion efficiency and reliability.
2Productivity
If phosphor conversion efficiency is increased to enhance red light output, then the LED package achieves better performance, but the phosphor becomes more susceptible to damage from high optical flux
Solution Approach 1:
The patent modifies the chemical composition parameters by selecting specific complex fluoride hosts (K2SiF6, Rb2GeF6, Cs2TiF6, etc.) and optimizing Mn4+ doping concentrations. These parameter changes create a phosphor material that maintains high conversion efficiency while inherently resisting optical flux damage through the stable crystal structure of the complex fluoride host.
Solution Approach 2:
The patent converts the potentially harmful high optical flux into a beneficial effect by using it to excite the Mn4+-doped phosphor, which then efficiently converts the absorbed energy into red light emission. The stable complex fluoride host structure ensures that the high optical flux does not cause damage but rather drives the desired luminescence process.
3Illumination intensity
If high flux levels are used to improve red light output, then the LED package achieves higher brightness, but the phosphor material suffers increased damage
Solution Approach 1:
The patent changes the material composition parameters by doping Mn4+ into complex fluoride hosts, creating a phosphor that can withstand high flux levels without damage. This compositional parameter change enables the phosphor to maintain durability while achieving high red light output through efficient conversion of the incident blue light.
Solution Approach 2:
The patent provides beforehand cushioning by selecting complex fluoride host structures with inherently high damage resistance thresholds. This prior selection of robust material structure cushions the phosphor against potential damage from high optical flux, allowing the system to operate at high flux levels for improved red light output without compromising durability.
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 results in improved performance and reliability of the LED package, with increased red light conversion efficiency and reduced damage at higher flux levels, achieving a correlated color temperature of 2500 K to 3700 K.
Implementation Method 1
manganese-activated luminescent materials which are excited by blue or violet light (such as blue light emitted by LED chips) and emit in the red region of the visible spectrum
Implementation Method 2
enhances red phosphor conversion efficiency and reduces susceptibility to damage from high optical flux
Data Source
AI summary
According to some embodiments, an apparatus and method are provided comprising: an enclosure defining a cavity within the enclosure, the cavity comprising a depth dimension; at least one LED chip; a layer comprising a blend of an encapsulant material and phosphor composition, the layer overlaying the at least one LED chip and disposed within the cavity; the phosphor composition comprising a yellow-green phosphor and a Mn4+ doped complex fluoride phosphor of formula I, Ax[MFy]:Mn4+ (I) where A is Li, Na, K, Rb, Cs, NR4 or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Hf, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; R is H, lower alkyl, or a combination thereof; x is the absolute value of the charge of the [Mfy] ion; and y is 5, 6, or 7; wherein the Mn4+ doped complex fluoride phosphor of formula I comprises a d50 particle size of from about 1 micrometers to about 10 micrometers, and the LED lighting apparatus, when activated, emits visible light comprising a correlated color temperature (CCT) of from about 2500 K to about 3700 K. Numerous other aspects are provided.