Nitride Fluorescent Material Sintering Control
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Solution Overview
Problem
Existing light emitting devices using nitride fluorescent materials face challenges in achieving high emission luminance due to sintering issues and impurity effects, which affect the efficiency and quality of the emitted light.
Innovation Solution
A method for producing a nitride fluorescent material involving the heat-treatment of a raw material mixture containing silicon nitride, elemental silicon, an aluminium compound, and a europium compound, with specific composition and particle size control to suppress sintering and enhance luminance, resulting in a nitride fluorescent material with improved light absorption and conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional heat treatment is applied to produce nitride fluorescent material, then the material can be formed, but sintering occurs which reduces emission luminance
Solution Approach 1:
The patent applies parameter changes by controlling the particle size distribution of raw materials (specifically maintaining D10 at 0.5-2.0 μm and D50 at 2.0-5.0 μm) and optimizing heat treatment temperature ranges (1700-2100°C) to suppress sintering while achieving high emission luminance. This resolves the contradiction by finding optimal parameter ranges that prevent excessive sintering.
Solution Approach 2:
The patent uses composite materials by combining multiple nitride compounds (Si3N4, AlN, Ca3N2, Sr3N2, Ba3N2) with specific particle size distributions to create a fluorescent material composition that resists sintering. The composite approach allows different components to contribute to both structural stability and high luminance emission.
2Productivity
If raw material mixture is heat treated to form nitride fluorescent material, then the material structure is formed, but impurity effects reduce light conversion efficiency
Solution Approach 1:
The patent controls the purity and particle size parameters of raw materials to minimize impurity formation during heat treatment. By specifying narrow particle size ranges and using high-purity starting materials, the process reduces impurity effects that would otherwise degrade light conversion efficiency.
Solution Approach 2:
The patent employs an inert nitrogen atmosphere during heat treatment to prevent oxidation and other unwanted reactions that would introduce impurities. This controlled environment ensures high purity of the final fluorescent material, directly improving light conversion efficiency by eliminating harmful impurity effects.
3Stability of the object's composition
If particle size is reduced to suppress sintering, then sintering is suppressed, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-grinding and classifying raw materials to achieve the desired particle size distribution (D10: 0.5-2.0 μm, D50: 2.0-5.0 μm) before heat treatment. This preliminary size control prevents sintering during subsequent processing while maintaining manageable manufacturing complexity through standardized particle preparation techniques.
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 method produces a nitride fluorescent material with higher luminance and improved light absorption and conversion efficiency, leading to enhanced performance in light emitting devices by controlling sintering and minimizing impurity effects, resulting in a more efficient and stable light emission.
Implementation Method 1
heat-treating a raw material mixture containing silicon nitride, elemental silicon, an aluminium compound, a calcium compound, and a europium compound
Implementation Method 2
a fluorescent material emitting red light when excited by the blue light
Data Source
AI summary
A method for producing a nitride fluorescent material having high emission luminance can be provided. The method includes heat-treating a raw material mixture containing silicon nitride, silicon, an aluminium compound, a calcium compound, and a europium compound.