Nitroxide Fluorescent Powder Core-Shell Gradient Oxygen Distribution
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Solution Overview
Problem
Current nitride red fluorescent powders for LEDs face a trade-off between aging and light decay resistance and luminescent efficiency, with existing solutions either improving one at the expense of the other, lacking a comprehensive solution that enhances both without reducing efficiency.
Innovation Solution
A nitroxide fluorescent powder with a specific inorganic compound structure featuring an increasing oxygen atom content distribution from core to surface, forming distinct zones that enhance chemical and thermal stability, and luminescent efficiency, comprising elements like Ca, Sr, and Eu, with a manufacturing method involving high-temperature calcination and post-treatment to create a stable and efficient luminescent device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxygen content is increased to improve chemical stability and aging resistance, then durability is improved, but luminescent efficiency decreases
Solution Approach 1:
The patent applies local quality by creating a gradient oxygen distribution where the surface layer has higher oxygen content (improving stability) while the core maintains lower oxygen content (preserving luminescent efficiency). This is achieved through controlled low-temperature calcination that limits oxygen diffusion to primarily the surface regions, thereby resolving the contradiction between durability and efficiency.
Solution Approach 2:
The fluorescent powder particle is segmented into distinct zones: a core region with low oxygen content for high luminescent efficiency and a surface layer with high oxygen content for improved chemical stability and aging resistance. This spatial segmentation allows each region to optimize its function without compromising the other.
2Use of energy by moving object
If oxygen content is limited to maintain luminescent brightness, then luminescent efficiency is maintained, but durability and aging resistance are reduced
Solution Approach 1:
The invention resolves this contradiction by applying local quality differently - the core maintains low oxygen content to preserve luminescent brightness while the surface layer is enriched with oxygen to provide durability and aging resistance. This localized differentiation allows simultaneous optimization of both parameters.
3Manufacturing precision
If alloy process is used to achieve low oxygen content and high phase purity, then manufacturing precision is improved, but durability is significantly reduced
Solution Approach 1:
The patent changes the processing parameters by introducing a low-temperature calcination step (400-800°C) after the alloy process. This parameter change enables oxygen to be selectively introduced into the surface layer without disrupting the core's low-oxygen, high-purity phase structure, thereby improving durability while maintaining manufacturing precision.
Solution Approach 2:
The low-temperature calcination is performed as a preliminary surface treatment before final product completion. This preliminary action of oxygen enrichment at the surface prepares the material for improved durability without affecting the core properties that provide high phase purity.
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 nitroxide fluorescent powder achieves good chemical stability, excellent aging and light decay resistance, high luminescent efficiency, and wide applicability, making it suitable for various luminescent devices, while the manufacturing method is simple and suitable for industrial mass production.
Implementation Method 1
a nitroxide fluorescent powder capable of being effectively excited with UV light, violet light, or blue light
Data Source
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AI summary
The present invention discloses a nitroxide fluorescent powder comprising an inorganic compound containing M, A, B, O, N, and R elements; in which the M element is at least one of Ca, Sr, Ba, Mg, Li, Na, and K, the A element is at least one of B, Al, Ga, and In, the B element is at least one of C, Si, Ge, and Sn, the R element is at least one of Ce, Eu, Lu, Dy, Gd, and Ho, characterized in that the inorganic compound forms a crystal in a crystalline phase, and the oxygen atom content in the crystal in a crystalline phase is in an increasing structural distribution from a core to surface of the crystal. The nitroxide fluorescent powder and the nitroxide illuminant of the present invention have the advantages of good chemical stability, good aging and light decay resistance, and high luminescent efficiency, and are useful for various luminescent devices. The preparation method of the present invention is easy and reliable and useful for industrial mass production.