Red Phosphor Composition for Broad Excitation Efficiency
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Solution Overview
Problem
Conventional red phosphors exhibit reduced luminous efficiency when excited by light with wavelengths in the range of 350 to 500 nm, which limits their effectiveness in various lighting applications.
Innovation Solution
A red phosphor composition is developed by substituting portions of MgF2, MgO, and GeO2 with specific elements such as Ca, Sc, Ga, and In, resulting in enhanced luminous efficiency when excited by light within the 350 to 500 nm range, as represented by formulas (1) to (5), which include specific ratios and elements like Ca, Sc, Ga, and In to optimize the emission peak.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If MgF2 is used in MGF phosphor composition, then the phosphor exhibits high luminous efficiency when excited by light having a wavelength of about 254 nm from a mercury lamp, but the luminous efficiency tends to decrease when excited by light having a wavelength in a range of 350 to 500 nm
Solution Approach 1:
The patent applies parameter changes by systematically varying the composition ratios of MgO, MgF2, and GeO2 in the phosphor material. By adjusting these compositional parameters within specific ranges, the phosphor achieves high luminous efficiency across the broader excitation wavelength range of 350-500 nm while maintaining the beneficial properties of conventional MGF phosphors.
Solution Approach 2:
The patent employs composite materials by creating a multi-component system consisting of MgO, MgF2, and GeO2 in optimized proportions. This composite approach allows the phosphor to combine the advantages of different materials, achieving both high luminous efficiency and broad excitation wavelength adaptability that cannot be achieved with single-component materials.
2Manufacturing precision
If the emission peak half width is narrowed to achieve high color purity, then color reproduction improves, but the manufacturing complexity increases
Solution Approach 1:
The patent achieves narrow emission peak half width through precise control of compositional parameters. By optimizing the ratios of MgO, MgF2, and GeO2 within specific ranges, the phosphor attains high color purity with a narrow emission peak, and this compositional optimization can be achieved through standard manufacturing processes without excessive complexity.
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 modified red phosphor composition achieves high luminous efficiency exceeding 200% compared to traditional MGF phosphors, with specific substitutions like Sc, Ga, and Ca enhancing the emission characteristics, particularly in the 600 to 670 nm wavelength range.
Implementation Method 1
A red phosphor represented by formula (1)... which exhibits a high luminous efficiency when excited by light having a wavelength in a range of 350 to 500 nm
Data Source
AI summary
The present disclosure provides a red phosphor represented by formula (1):(x-a-b)MgO.aM1O.bM2O1.5.yMgF2.fM6X2.(1-g)GeO2.gM7O1.5:zMn4+ (1)where x, y, z, a, b, f, and g satisfy 1.144<x≤11.0, 0<y<1.597, 0<z<0.1, 0<a<1.0, 0≤b≤1.0, 0<f≤2.0, 0≤g<0.484, 1.144<(x-a-b), and b and g satisfy b+g≠0; M1 is at least one element selected from the group consisting of Ca, Sr, Ba, and Zn; M2 is at least one element selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu; M6 is at least one element selected from the group consisting of Mg, Ca, Sr, Ba, and Zn; M7 is at least one element selected from the group consisting of B, Al, Ga, and In; and X is at least one element selected from the group consisting of F, Cl, Br, and I, and M6X2 is other than MgF2.