Zirconium-Coated Fluoride Phosphor for Harsh-Environment Reliability
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Solution Overview
Problem
The reliability of light-emitting devices using manganese-doped fluoride phosphors is compromised in harsh environments due to manganese ion instability.
Innovation Solution
A fluoride phosphor is developed with a zirconium-containing fluorine compound on its surface, composed of specific elements and ratios, enhancing stability and reliability in high-temperature and high-humidity conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a manganese-doped fluoride phosphor is used to achieve narrow full width at half maximum and high color purity, then the emission peak narrowness is improved, but the reliability decreases in harsh environments due to manganese ion instability
Solution Approach 1:
The patent applies local quality by coating only the surface of the fluoride phosphor particles with aluminum oxide, rather than modifying the entire bulk material. This surface coating locally protects the manganese ions from environmental degradation while preserving the bulk phosphor's optical properties including its narrow emission peak. The coating thickness and distribution are controlled to provide protection without significantly altering the phosphor's overall characteristics.
Solution Approach 2:
The patent creates a composite material structure by combining manganese-doped fluoride phosphor particles with an aluminum oxide coating layer. This composite structure integrates the advantages of both materials: the fluoride phosphor provides narrow emission peak and high color purity, while the aluminum oxide coating provides environmental stability and protects the manganese ions from degradation in harsh conditions.
2Reliability
If a surface coating is applied to protect manganese-doped phosphor from deterioration, then the reliability is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by performing the aluminum oxide coating process during the phosphor manufacturing stage, before the phosphor is used in the final light-emitting device. This integrated approach incorporates the protective coating as part of the base material production process, avoiding the need for separate coating operations later and reducing overall manufacturing complexity.
Solution Approach 2:
The patent utilizes parameter changes by controlling the coating thickness, composition ratio, and formation conditions of the aluminum oxide layer to achieve optimal protection while maintaining simple manufacturing. By adjusting these parameters within specific ranges, the patent achieves reliable protection without requiring complex multi-layer structures or sophisticated coating equipment.
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 fluoride phosphor maintains luminous flux and color stability, improving the reliability of light-emitting devices in challenging environments.
Implementation Method 1
a fluorine compound containing zirconium and disposed on at least a portion of a surface of the fluoride particle
Implementation Method 2
a fluoride phosphor in which manganese is added is known as a red-light emitting phosphor having a narrow full width at half maximum of the emission peak
Data Source
AI summary
Provided is a fluoride phosphor including a fluoride particle and a fluorine compound containing zirconium and disposed on at least a portion of the surface of the fluoride particle. The fluoride particle has a composition including an element M including at least one selected from the group consisting of Group 4 elements, Group 13 elements, and Group 14 elements; at least one selected from the group consisting of an alkali metal and an ammonium ion; manganese; and fluorine atoms. In the composition, when the total number of moles of the alkali metal and the ammonium ion is 2, the number of moles of the manganese is greater than 0 and less than 0.2, the total number of moles of the element M is greater than 0.8 and less than 1, and the number of moles of the fluorine atoms is greater than 5 and less than 7.