Aluminate Fluorescent Material Two-Step Heat Treatment
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Solution Overview
Problem
Manganese-activated aluminate fluorescent materials exhibit insufficient emission brightness when excited with near UV to blue light, limiting their effectiveness in light emitting devices.
Innovation Solution
A method of producing aluminate fluorescent materials involving a two-step heat treatment process to achieve large particle diameters, using a mixture of Ba, Sr, Ca, Mn, Eu, and Al compounds, with optional Mg, to enhance emission intensity in the near UV to blue region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If manganese-activated aluminate fluorescent material is used, then it can be excited with vacuum UV rays to give high emission brightness, but when combined with a light emitting element having an emission peak wavelength in the near UV to blue region, the emission brightness is insufficient
Solution Approach 1:
The patent changes the particle size parameter of the fluorescent material to greater than 10 μm (specifically 13 μm or more), which fundamentally alters the excitation characteristics. This parameter change enables the material to be effectively excited by near UV to blue light (380-485 nm) while maintaining high emission brightness, resolving the contradiction between excitation wavelength adaptability and emission intensity
Solution Approach 2:
The patent uses a composite fluorescent material containing multiple elements (Ba, Sr, Ca, Mn, Eu, Al, and optionally Mg) in specific compositional ratios. This composite structure creates new optical properties that allow simultaneous excitation by near UV to blue light and maintenance of high emission brightness, overcoming the limitation of single-element aluminate materials
2Illumination intensity
If the particle diameter is increased to enhance emission intensity, then the emission brightness improves, but the manufacturing complexity increases due to the two-step heat treatment process
Solution Approach 1:
The patent segments the heat treatment process into two distinct steps: first heat treatment to form initial calcined product with controlled particle diameter, and second heat treatment to achieve final large particle size (>10 μm). This segmentation allows each step to be optimized independently, making the complex process more controllable and manufacturable
Solution Approach 2:
The first heat treatment serves as a preliminary action that creates a calcined product with specific particle characteristics before the second heat treatment. This preliminary preparation ensures that the final large particle size is achieved more efficiently and with better control over the emission properties
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 aluminate fluorescent materials with high emission intensity in the near UV to blue region, suitable for use in light emitting devices, improving their performance and efficiency.
Implementation Method 1
an aluminate fluorescent material having a high emission intensity when photoexcited with light in a near UV to blue region
Implementation Method 2
a step of subjecting a first mixture prepared by mixing a compound containing at least one metal element selected from the group consisting of Ba, Sr and Ca, at least one compound selected from a compound containing Mn and a compound containing Eu, and a compound containing Al, in which a compound containing Mg may be optionally mixed, to first heat treatment to give a first calcined product
Data Source
AI summary
Disclosed are a method of producing an aluminate fluorescent material, such an aluminate fluorescent material, and a light emitting device. The aluminate fluorescent material production method includes: subjecting a first mixture prepared by mixing a compound containing at least one metal element selected from the group consisting of Ba, Sr and Ca, and at least one compound selected from the group consisting of a compound containing Mn and a compound containing Eu, and a compound containing Al, in which a compound containing Mg may be optionally mixed, to first heat treatment to give a first calcined product having an average particle diameter D1, as measured according to a Fisher Sub-Sieve Sizer method, of 6 μm or more; and subjecting a second mixture prepared by mixing a compound containing at least one metal element selected from the group consisting of Ba, Sr and Ca, at least one compound selected from the group consisting of a compound containing Mn and a compound containing Eu, and a compound containing Al, and the first calcined product whose content is 10% by mass or more and 90% by mass or less relative to the total amount of the second mixture, in which a compound containing Mg may be optionally mixed, to second heat treatment to give a second calcined product.