Eu-Activated Phosphor Composition for Stable Red-NIR Emission

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Solution Overview

Problem

Conventional phosphors experience significant brightness deterioration when exposed to high-energy excitation sources, limiting their application in lighting technologies such as LEDs and display devices.

Innovation Solution

A new phosphor with a Ba26Si51O284 crystal structure, activated by elements like Eu, which emits high-intensity red or near-infrared light even when excited by visible or ultraviolet light, maintaining emission intensity and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional phosphors are used with high-energy excitation sources, then the phosphor can emit visible light, but the luminance deteriorates significantly

Engineering Contradiction:
Improveemission intensityVSAvoidbrightness stability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the phosphor by incorporating nitrogen into the crystal structure (forming sialon, oxynitride, or nitride phosphors). This compositional parameter change fundamentally alters the phosphor's resistance to high-energy excitation, maintaining luminance while enabling excitation by UV, blue light, or electron beams.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates composite phosphor materials by combining silicon, aluminum, oxygen, and nitrogen in specific ratios to form sialon, oxynitride, or nitride crystal structures. These composite materials exhibit superior brightness stability under high-energy excitation compared to conventional single-component phosphors.

Inventive Principle:
Principle #40Composite materials

2Reliability

If nitrogen-containing inorganic crystals are used as host crystal, then brightness deterioration is reduced, but manufacturing complexity increases

Engineering Contradiction:
Improvebrightness stabilityVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by incorporating nitrogen specifically at certain crystal lattice positions within the phosphor structure, rather than uniformly throughout. This targeted incorporation achieves brightness stability while allowing the rest of the manufacturing process to remain relatively simple and compatible with existing production methods.

Inventive Principle:
Principle #3Local quality

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 excellent durability and high emission intensity across a specific wavelength range, suitable for use in white LEDs, liquid crystal display backlights, projectors, and infrared devices, with minimal brightness deterioration.

Implementation Method 1

the phosphor is excited by an excitation source with high energy such as a vacuum ultraviolet ray, an ultraviolet ray, an electron beam, and blue light so as to emit a visible light ray

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP3992264B1Fluorescent body, method for manufacturing same, and light-emitting device using same
Publication Date: 2023.10.25 NAT INST FOR MATERIALS SCI
  • EP3992264B1 patent drawingFigure 1~2
  • EP3992264B1 patent drawingFigure 3~4
  • EP3992264B1 patent drawingFigure 5

AI summary

Provided are a new phosphor having emission characteristics different from the conventional nitride or oxynitride phosphor, a manufacturing method, and a light-emitting device. In an embodiment, the phosphor may include inorganic substance having crystal represented by A26(D, E)51X86 including at least A, D, X (A is at least one kind of element selected from Mg, Ca, Sr, and Ba; and D is Si, and X is at least one kind of element selected from O, N, and F); and further includes, if necessary, E (E is at least one kind of element selected from B, Al, Ga, and In) wherein the crystal further includes M (M is at least one kind of element selected from Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, and Yb). Upon irradiation of excitation source, the maximum value of emission peak in a wavelength range from 630 nm to 850 nm may occur.