Fluoride Phosphor Production via Dissolution and Precipitation
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Solution Overview
Problem
Conventional fluoride phosphors exhibit inferior luminescence properties and inadequate reliability in terms of heat resistance, humidity resistance, and quality stability, limiting their practical application in light-emitting devices.
Innovation Solution
A fluoride phosphor production method involving the addition of solid silicon dioxide and a manganese compound that supplies manganese in a valence other than +7 to an aqueous solution, resulting in a fluoride phosphor with enhanced luminescence intensity and reliability, represented by the formula A2SiF6:Mn, where element A is an alkali metal such as potassium, with specific conditions for the manganese content, particle size, and production process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional fluoride phosphors are used, then production is simpler, but luminescence intensity and reliability are inferior
Solution Approach 1:
The patent applies preliminary action by pre-dissolving silicon dioxide and manganese compound in hydrofluoric acid before mixing with the aqueous solution containing alkali metal and fluorine. This pre-preparation step ensures proper dissolution and distribution of components, leading to enhanced luminescence intensity and reliability of the resulting fluoride phosphor without significantly complicating the overall production process.
2Reliability
If conventional fluoride phosphors are used, then manufacturing is easier, but heat resistance and humidity resistance are inadequate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the concentrations of hydrofluoric acid (40-70 mass%), alkali metal compound (0.1-10 mol/L), and fluorine compound (0.1-10 mol/L), along with the dissolution time (1-24 hours) and temperature (20-100°C). These optimized parameters result in fluoride phosphors with superior heat resistance and humidity resistance while maintaining ease of manufacture through a straightforward aqueous solution process.
3Stability of the object's composition
If conventional fluoride phosphors are used, then production process is simpler, but quality stability shows high variation
Solution Approach 1:
The patent applies feedback by systematically optimizing and controlling multiple process parameters including hydrofluoric acid concentration (40-70 mass%), dissolution time (1-24 hours), temperature (20-100°C), and the sequential addition of reagents. This controlled approach with monitored parameters ensures consistent quality and low variation in the produced fluoride phosphors, achieving high quality stability.
4Illumination intensity
If red phosphors with sharp luminescence spectrum are used, then color rendering is improved, but luminance decreases due to low visual sensitivity
Solution Approach 1:
The patent applies composite materials by creating fluoride phosphors with the general formula A2SiF6:Mn, where A is an alkali metal (Li, Na, K, Rb, or Cs). This composite structure combines the fluoride crystal lattice with manganese activators, producing a sharp luminescence spectrum with high luminance output. The resulting material achieves both excellent color rendering properties and high luminance, overcoming the limitation of conventional red phosphors.
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 resulting fluoride phosphor demonstrates high luminescence intensity, excellent heat resistance, and stability, leading to improved performance in light-emitting devices with reduced luminance degradation under high-temperature and high-humidity conditions.
Implementation Method 1
a fluoride phosphor production method involving the addition of solid silicon dioxide and a manganese compound that supplies manganese in a valence other than +7 to an aqueous solution, resulting in a fluoride phosphor with enhanced luminescence intensity
Implementation Method 2
addition of solid silicon dioxide and a manganese compound that supplies manganese in a valence other than +7 to an aqueous solution
Implementation Method 3
resulting in a fluoride phosphor with enhanced luminescence intensity and reliability
Data Source
AI summary
The purpose of the present invention is to provide a fluoride phosphor (represented by the general formula A2SiF6:Mn) having high luminescence intensity and reliability, a high-luminance light-emitting device using this phosphor, and a production method for this phosphor.The production method for a fluoride phosphor represented by the general formula A2SiF6:Mn (where element A is an alkali metal element including at least potassium), wherein the fluoride phosphor production method comprises: a step of preparing an aqueous solution wherein element A and fluorine are dissolved in a solvent; and a step of adding, to the aqueous solution, solid silicon dioxide and a manganese compound that supplies manganese having a valence other than +7; wherein an added amount of the manganese compound is within a range such that an Mn content in the fluoride phosphor becomes at least 0.1 mass % and at most 1.5 mass %; and the fluoride phosphor precipitates as the silicon dioxide concurrently dissolves into the aqueous solution.