Barium-Rich Halophosphate Phosphor High-Temperature Stability
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Solution Overview
Problem
Conventional blue-green light-emitting phosphors suffer from poor high-temperature properties, leading to performance degradation and increased maintenance costs due to high strontium content, which affects their durability and emission intensity under high-temperature conditions.
Innovation Solution
A blue-green light-emitting phosphor with a higher content of barium (Ba) within a specific molar ratio range, exceeding 60% to 95% of the alkaline earth metal elements, is developed, enhancing high-temperature properties, brightness, and half width when excited by near-ultraviolet rays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high content of strontium (Sr) is used to improve light-emitting properties, then brightness and half width are improved, but high-temperature property deteriorates
Solution Approach 1:
The patent changes the compositional parameters by strictly limiting Sr content to 3 mol% or less while optimizing Ba content (4-12 mol%) and Eu content (0.1-2 mol%). This parameter adjustment resolves the contradiction by reducing Sr-induced high-temperature degradation while maintaining adequate brightness through Ba and Eu optimization.
Solution Approach 2:
The patent creates a composite phosphor system with specific ratios of Ba, Sr, Ca, and Eu elements in the halophosphate structure. By designing this composite material with controlled composition ranges, it achieves both sufficient light-emitting properties and improved high-temperature stability through synergistic element interactions.
2Illumination intensity
If high content of strontium (Sr) is used to improve light-emitting properties, then half width is improved, but durability under high-temperature conditions deteriorates
Solution Approach 1:
The patent adjusts compositional parameters to limit Sr to 3 mol% or less while optimizing Ba (4-12 mol%) and Eu (0.1-2 mol%) content. This parameter optimization maintains adequate half width through Ba-dominated emission while significantly improving durability by eliminating excessive Sr that causes high-temperature degradation.
Solution Approach 2:
The patent designs a composite halophosphate material with specific element ratios where Ba provides the main emission bandwidth, Sr provides minor enhancement within limits, and Eu acts as activator. This composite structure achieves sustained durability under high-temperature operation while maintaining required half width characteristics.
3Illumination intensity
If high content of strontium (Sr) is used to improve light-emitting properties, then emission intensity is improved, but maintenance cost increases due to quick usage
Solution Approach 1:
The patent optimizes compositional parameters by limiting Sr to 3 mol% or less and optimizing Ba (4-12 mol%) and Eu (0.1-2 mol%) content. This achieves sustained emission intensity through stable high-temperature performance, reducing frequency of replacement and lowering maintenance costs despite slightly reduced initial intensity compared to high-Sr phosphors.
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 phosphor exhibits improved high-temperature stability, maintaining emission intensity and broadening the light-emitting area, resulting in enhanced durability and reduced maintenance costs, while also achieving higher color-rendering properties for white-light-emitting devices.
Implementation Method 1
a blue-green light-emitting phosphor which, upon irradiation with a near-ultraviolet ray, is excited to thereby emit blue-green visible light
Data Source
AI summary
An object of the invention is to provide a blue-green light-emitting phosphor having excellent high-temperature property and excellent light-emitting properties such as brightness and half width. The phosphor is constituted of a plurality of alkaline earth metal elements including a barium element, phosphoric acid and a halogen element, and Eu as an activator, in which the molar ratio of the barium element to the total content of the alkaline earth metal elements is larger than 60% and smaller than 95%, and upon irradiation with a near-ultraviolet ray, the blue-green light-emitting phosphor is excited to thereby emit blue-green visible light.