Stannate Fluorescent Material Core-Shell Structure for FED Brightness
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Solution Overview
Problem
Field emission display (FED) fluorescent materials face challenges with low emission intensity due to instability of sulfide materials reacting with cathode components, leading to weakened electron emission and brightness saturation issues.
Innovation Solution
A stannate fluorescent material with a core-shell structure, where metal nanoparticles (Ag, Au, Pt, Pd, or Cu) serve as the core, SnO2 as the intermediate layer, and A2-xSnO4:Eux as the outer shell, is developed, enhancing luminous intensity through improved internal quantum efficiency and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sulfide fluorescent material is used for FED, then the material can be manufactured with existing CRT technology, but the emission intensity becomes weak due to reaction with cathode components
Solution Approach 1:
The patent uses a composite fluorescent material comprising red fluorescent particles (K2SiF6:Mn4+) and yellow fluorescent particles (Y3Al5O12:Ce3+ or Lu3Al5O12:Ce3+) in specific weight ratios (3:7 to 7:3). This composite structure combines the advantages of both materials to achieve high emission intensity and red color purity while maintaining stability with the cathode, resolving the contradiction between manufacturability and emission intensity.
2Adaptability or versatility
If sulfide fluorescent material is used, then existing CRT fluorescent material can be utilized, but brightness saturation occurs at high current densities
Solution Approach 1:
The patent changes the compositional parameters by using a composite of K2SiF6:Mn4+ (red) and YAG:Ce3+ or LuAG:Ce3+ (yellow) fluorescent materials with specific weight ratios. This parameter change enables the material to maintain linear luminous intensity characteristics across a wide current density range (10-100 μA·cm−2), avoiding brightness saturation while maintaining compatibility with existing manufacturing processes.
3Ease of manufacture
If sulfide fluorescent material is used, then conventional fluorescent material can be applied, but chromaticity performance deteriorates
Solution Approach 1:
The patent employs a composite fluorescent material system combining K2SiF6:Mn4+ (providing red emission at 620-680 nm) with YAG:Ce3+ or LuAG:Ce3+ (providing yellow emission). This composite approach achieves superior chromaticity with red color purity exceeding 0.9 while utilizing conventional fluorescent material components that can be manufactured with existing technology.
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 stannate fluorescent material exhibits higher luminous intensity and stability, avoiding toxic sulfide production, making it suitable for display and lighting applications while maintaining environmental safety.
Implementation Method 1
a core-shell structure is formed by coating at least one metal nanoparticles selected from the group consisting of Ag, Au, Pt, Pd, and Cu, since metal nanoparticles can improve the internal quantum efficiency of the fluorescent material
Implementation Method 2
A stannate fluorescent material, having a formula: A2-xSnO4:Eux@SnO2@My where A is selected from the group consisting of Ca, Sr, and Ba; M is at least one metal nanoparticles selected from the group consisting of Ag, Au, Pt, Pd, and Cu
Data Source
AI summary
The present invention provides a stannate fluorescent material having a formula: A2-xSnO4:Eux@SnO2@My; wherein A is selected from the group consisting of Ca, Sr, and Ba; M is at least one metal nanoparticles selected from the group consisting of Ag, Au, Pt, Pd, and Cu; 0<x≦0.05; y is a mole ratio of M to Sn, and 0<y≦1×10−2; @ represents coating, in the stannate fluorescent material, M serves as a core, SnO2 serves as an intermediate layer shell, and A2-xSnO4:Eux serves as an outer layer shell. In the stannate fluorescent material, a core-shell structure is formed by coating at least one metal nanoparticles selected from the group consisting of Ag, Au, Pt, Pd, and Cu, since metal nanoparticles can improve the internal quantum efficiency of the fluorescent material, the stannate fluorescent material exhibits a higher luminous intensity.