γ-AlON Fluorescent Material Fluorine Control
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Solution Overview
Problem
The γ-AlON fluorescent material, when combined with light emitting elements in the near-UV to blue region, has a desired but unmet goal of enhancing light emission intensity, and existing methods fail to achieve this effectively due to issues with fluorine content and crystal stability.
Innovation Solution
A method involving the preparation of a mixture containing Mn, Li, Mg, aluminum oxide, and aluminum nitride with controlled fluorine levels, followed by heat treatments to produce calcined products with specific particle diameters, promoting crystal growth and stability, and an annealing treatment to enhance light emission intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If fluorine is added to the γ-AlON fluorescent material to improve crystal growth, then crystal stability is improved, but light emission intensity deteriorates due to fluorine-induced dullness
Solution Approach 1:
The patent applies parameter changes by precisely controlling the fluorine content to 150 ppm or less (changing the concentration parameter) and optimizing the particle diameter to 16.0 μm or more (changing the size parameter). This resolves the contradiction by finding the optimal parameter range where crystal stability is maintained while avoiding fluorine-induced dullness that reduces light emission intensity.
2Illumination intensity
If particle diameter is increased to improve light emission intensity, then light emission intensity is improved, but manufacturing precision deteriorates due to difficulty in controlling particle size distribution
Solution Approach 1:
The patent applies preliminary action by conducting a first heat treatment to obtain a first calcined product with controlled particle diameter of 10.0 μm or more, then using this as a starting material for a second heat treatment. This preliminary preparation step enables precise control of the final particle size distribution while achieving the required 16.0 μm or more average diameter for high light emission intensity.
3Illumination intensity
If Mn content is increased to improve light emission intensity, then light emission intensity is improved, but crystal structure stability deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the Mn content within specific compositional ranges (as defined in the compositional formula) and controlling the heat treatment parameters. This resolves the contradiction by finding the optimal parameter combination where sufficient Mn is present to provide high light emission intensity while the crystal structure remains stable.
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 results in a γ-AlON fluorescent material with high light emission intensity and stable crystal structure, suitable for use in light emitting devices, improving color purity and reducing fluorine-induced dullness, and enabling efficient light conversion in the near-UV to blue region.
Implementation Method 1
subjecting the first mixture to a first heat treatment to obtain a first calcined product
Implementation Method 2
subjecting the second mixture to a second heat treatment to obtain a second calcined product
Implementation Method 3
The γ-AlON fluorescent material is excited with blue light having a light emission peak wavelength in a range of, for example, 410 nm or more and 470 nm or less to thereby emit green light
Data Source
AI summary
A method for producing a γ-AlON fluorescent material, comprising: preparing a first mixture containing a compound containing Mn, a compound containing Li, a compound containing Mg, an aluminum oxide, and an aluminum nitride, in which the amount of fluorine is 150 ppm by mass or less relative to the total amount of the first mixture excluding fluorine, and subjecting the first mixture to a first heat treatment to obtain a first calcined product having an average particle diameter D1, as measured according to a Fisher Sub-Sieve Sizer method, of 10.0 μm or more; and preparing a second mixture containing the first calcined product, a compound containing Mn, a compound containing Li, a compound containing Mg, an aluminum oxide, and an aluminum nitride, in which the amount of fluorine is 150 ppm by mass or less relative to the total amount of the second mixture excluding fluorine, and subjecting the second mixture to a second heat treatment to obtain a second calcined product having an average particle diameter D2, as measured according to the Fisher Sub-Sieve Sizer method, of 16.0 μm or more, wherein the second mixture contains the first calcined product in an amount of more than 20% by mass and 82% by mass or less.