Silicate Fluorescent Material Composition for Narrow Green Emission
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Solution Overview
Problem
Existing green-emitting fluorescent materials in light emitting devices suffer from broad light emission peaks, low light emission intensity, and poor light resistance due to photodegradation under continuous irradiation.
Innovation Solution
A silicate fluorescent material with a composition represented by A11-w-xA2wM1x(Li3SiO4):Euy, where A1 and A2 are alkali elements, M1 is selected from Mg, Ca, Sr, Ba, Y, and La, and w, x, y satisfy specific molar ratios, is produced by mixing oxide compounds and heat-treating them under reducing conditions to stabilize the crystal structure and maintain divalent Eu2+ for enhanced emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional green-emitting fluorescent materials are used, then the light emission intensity is maintained at acceptable levels, but the light emission peak has a broad full width at half maximum reducing color reproducibility
Solution Approach 1:
The patent changes the chemical composition parameters of the fluorescent material by incorporating specific alkali elements (A1 from Rb/Cs group, A2 from K/Na/Li group) and alkaline earth elements (M1 from Mg/Ca/Sr/Ba/Y/La group) in controlled molar ratios. This compositional parameter change results in a narrower full width at half maximum of the light emission peak, thereby improving color reproducibility while maintaining acceptable light emission intensity.
2Duration of action of stationary object
If fluorescent materials are used for continuous operation, then the light emission intensity is maintained, but photodegradation occurs reducing light resistance
Solution Approach 1:
The patent creates a composite fluorescent material structure combining multiple elements (alkali elements A1 and A2, alkaline earth elements M1, lithium, silicon, and europium activator) in a specific compositional ratio. This composite structure enhances the crystal lattice stability and protects against photodegradation during continuous operation, thereby improving light resistance while maintaining light emission intensity over time.
3Illumination intensity
If the crystal structure is stabilized through heat treatment, then the light emission intensity is enhanced, but the production process complexity increases
Solution Approach 1:
The patent employs heat treatment at a specific temperature range (400-800°C) in a reducing atmosphere to stabilize the crystal structure and enhance light emission intensity. By controlling the temperature parameter and atmospheric conditions, the process achieves desired material properties while maintaining reasonable production complexity through standardized thermal processing 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 silicate fluorescent material achieves a narrow full width at half maximum, high light emission intensity, and improved light resistance against photodegradation, enabling wider color reproducibility and stability in light emitting devices.
Implementation Method 1
a light emitting element irradiating the silicate fluorescent material with excitation light
Implementation Method 2
first heat-treating the raw material mixture at a first temperature in the range of 400° C. or higher and 800° C. or lower in a reducing atmosphere
Implementation Method 3
first heat-treating the raw material mixture at a first temperature in the range of 400° C. or higher and 800° C. or lower in a reducing atmosphere
Data Source
AI summary
A silicate fluorescent material has a composition represented by the following formula (1):A11-w-xA2wM1x(Li3SiO4):Euy (1)wherein A1 represents at least one first alkali element selected from the group consisting of Rb and Cs, A2 represents at least one second alkali element selected from the group consisting of K, Na, and Li, M1 represents at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Y, and La, and w, x, and y satisfy 0<w<1.0, 0<x≤0.125, w+x≤1.0, and 0<y≤0.08.