A2MF6:Mn Phosphor Fluorescence Intensity Optimization
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Solution Overview
Problem
Conventional red light emitting phosphors have insufficient optical properties and require improvement in fluorescence intensity for practical use.
Innovation Solution
A phosphor represented by the formula A2MF6:Mn, where A is an alkali metal and M is a tetravalent metallic element, with specific light absorption and particle size characteristics, used in a light emitting device with a blue light source, and produced through methods involving hydrofluoric acid solutions and precipitation steps to enhance fluorescence intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional red light emitting phosphor (A2[MF6]:Mn4+) is used, then the phosphor can be produced by dissolving K2MnF6 crystals in hydrofluoric acid solution, but the optical properties are insufficient and fluorescence intensity is low
Solution Approach 1:
The patent optimizes specific parameters including Mn4+ content (0.01-5 mol%), particle size (10-35 μm), light absorption rate at 300-350 nm (≤67%), and light absorption rate at 400-500 nm (≥65%). These parameter changes transform the conventional phosphor with insufficient optical properties into one with high fluorescence intensity and reliable optical characteristics for practical LED applications
2Use of energy by moving object
If the phosphor absorbs too much light in the 300-350 nm range, then more excitation energy can be captured, but the minimal light absorption rate should be 67% or less to achieve optimal fluorescence emission
Solution Approach 1:
The patent establishes the optimal light absorption rate in the 300-350 nm range at 67% or less, balancing excitation energy capture with energy loss prevention. This parameter optimization ensures that the phosphor absorbs sufficient energy for fluorescence emission while minimizing unnecessary energy loss, achieving efficient energy utilization for high luminance output
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 phosphor achieves efficient fluorescence emission and high luminance in light emitting devices, with internal and external quantum efficiencies of 70% and 57% respectively, improving upon previous phosphor technologies.
Implementation Method 1
a phosphor represented by the general formula: A2MF6:Mn4+... having a maximum light absorption rate in a wavelength range of 400 nm or more and 500 nm or less of 65% or more... efficient fluorescence emission and high fluorescence intensity
Implementation Method 2
dissolving raw materials in hydrofluoric acid to obtain an aqueous hydrofluoric acid solution... dissolving K2 MnF6 crystals containing an A2[MF6] crystal as a matrix for the phosphor and Mn as an emission center in a hydrofluoric acid solution
Implementation Method 3
evaporating the solution to dryness... the precipitating step comprises evaporating the aqueous hydrofluoric acid solution after the dissolving step
Data Source
AI summary
Provided is a phosphor represented by the general formula: A2MF6:Mn. The elements A each represents an alkali metal element, the element M represents one or more tetravalent metallic elements selected from Si, Ge, Sn, Ti, Zr and Hf. The phosphor has a minimal light absorption rate in a wavelength range of 300 nm or more and 350 nm or less of 67% or less, and a maximum light absorption rate in a wavelength range of 400 nm or more and 500 nm or less of 65% or more. The phosphor has a Mn content of 0.3% by mass or more and 1.5% by mass or less.