Mn4+ Doped Phosphor Semi-Continuous Synthesis
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Solution Overview
Problem
Existing processes for producing Mn4+ doped red-emitting phosphors result in a broad range of particle sizes, leading to clogging issues and non-homogeneous distributions, which affect the performance and manufacturing efficiency of LED packages.
Innovation Solution
A semi-continuous flow process involving gradual addition of solutions containing sources of M and Mn to a reactor in the presence of A, with periodic discharge of the product liquor, to control particle size and distribution, resulting in a more homogeneous and efficient product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If batch processes are used to prepare Mn4+ doped phosphors, then the process is simple to implement, but the particle size distribution is broad and large particles are produced
Solution Approach 1:
The batch process is segmented into multiple continuous addition stages where reactant solutions are added gradually over time rather than all at once. This temporal segmentation allows better control over nucleation and growth phases, resulting in narrower particle size distribution while maintaining process simplicity.
Solution Approach 2:
The invention employs periodic addition of reactant solutions during the synthesis process. By controlling the rate and timing of solution addition, the process achieves consistent particle size distribution. The periodic action allows maintenance of simple batch reactor operation while obtaining precise particle size control.
2Productivity
If large particles are produced, then the synthesis process is faster, but clogging of dispensing equipment occurs
Solution Approach 1:
The invention changes the kinetic parameters of the synthesis process by controlling the rate of reactant addition and reaction temperature. These parameter changes result in the formation of smaller particles with sizes optimized to prevent clogging of dispensing equipment while maintaining efficient synthesis rates.
3Productivity
If large particles are produced, then the synthesis process is faster, but non-homogeneous distribution results
Solution Approach 1:
The invention maintains continuous useful action by gradually adding reactant solutions throughout the synthesis process rather than completing the reaction in a single step. This continuous supply of reactants ensures uniform nucleation and growth conditions throughout the reaction volume, producing homogeneous particle distributions while maintaining productive synthesis rates.
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 process yields Mn4+ doped phosphors with a narrower particle size distribution, improving manufacturing efficiency and maintaining performance in lighting and display applications.
Implementation Method 1
These materials absorb blue light strongly and efficiently emit in a range between about 610 nm and 658 nm
Implementation Method 2
Processes for preparing the materials described in the patent andscientific literature typically involve mixing the raw materials and precipitating the product
Data Source
AI summary
A process for preparing a Mn+4 doped phosphor of formula IAx[MFy|:Mn+4 Iincludes gradually adding a first solution to a second solution and periodically discharging the product liquor from the reactor while volume of the product liquor in the reactor remains constant; whereinA is Li, Na, K, Rb, Cs, or a combination thereof;M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof;x is the absolute value of the charge of the [MFy] ion; andy is 5, 6 or 7.The first solution includes a source of M and HF and the second solution includes a source of Mn to a reactor in the presence of a source of A.