Beta-sialon Fluorescent Material Production via Two-Step Purification

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Solution Overview

Problem

Current methods for producing β-sialon fluorescent materials do not effectively enhance emission intensity, as they often result in unstable phases and impurities that interfere with emission, and existing treatments can damage the material or fail to remove impurities efficiently.

Innovation Solution

A method involving a first composition of aluminium, oxygen, and europium-containing silicon nitride, followed by heat treatment, contact with a basic substance to form a highly translucent solubilized product, and subsequent acidic liquid medium treatment to remove impurities and enhance emission intensity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If heat treatment is performed at high temperature to enhance emission intensity, then emission intensity is improved, but unstable phases and impurities are generated that interfere with emission

Engineering Contradiction:
Improveemission intensityVSAvoidunstable phases and impurities
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes the harmful unstable phases and impurities generated during high-temperature heat treatment through a two-step chemical treatment process: first treating with a basic substance to solubilize the impurities, then treating with an acidic liquid medium to remove the solubilized products, thereby preserving the emission intensity while eliminating the harmful byproducts

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses a basic substance as an intermediary agent that temporarily solubilizes the unstable phases and impurities generated during heat treatment, allowing them to be subsequently removed by acidic treatment without directly damaging the β-sialon fluorescent material structure

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-generated harmful factors

If existing treatment methods are used to remove impurities, then some impurities are removed, but the material is damaged or impurities are not efficiently removed

Engineering Contradiction:
ImproveimpuritiesVSAvoidmaterial integrity
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent employs a basic substance as an intermediary that gently solubilizes impurities without directly attacking or damaging the β-sialon fluorescent material structure, followed by acidic treatment to remove the solubilized impurities, achieving effective purification while preserving material integrity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical environment parameters through sequential basic and acidic treatments, creating conditions that selectively dissolve impurities while maintaining the stability of the fluorescent material, thereby removing impurities efficiently without material damage

Inventive Principle:
Principle #35Parameter changes

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 significantly enhances emission intensity by thermally decomposing unstable phases, reducing damage to the material, and effectively removing impurities, resulting in improved luminance and crystallinity of the β-sialon fluorescent material.

Implementation Method 1

heat treating the first composition

Methodology Applied
Scientific EffectThermal decomposition: Thermolysis

Implementation Method 2

contacting the heat-treated composition and a basic substance to obtain a second composition

Methodology Applied
Scientific EffectSolubilization: Solvation

Implementation Method 3

contacting the second composition and an acidic liquid medium containing an acidic substance

Methodology Applied
Scientific EffectChemical reaction with acidic substance: Chemical Bonding

Data Source

PatentUS11753302B2Method of producing beta-sialon fluorescent material
Publication Date: 2023.09.12 NICHIA CORP

AI summary

Provided a method of producing a β-sialon fluorescent material having excellent emission intensity. The method includes providing a first composition containing aluminum, an oxygen atom, and a europium-containing silicon nitride, heat treating the first composition, contacting the heat-treated composition and a basic substance to obtain a second composition, and contacting the second composition resulting from contacting the heat-treated composition with the basic substance and an acidic liquid medium containing an acidic substance.