Red-NIR Phosphor Composition for Stable High-Intensity Emission
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Solution Overview
Problem
Conventional phosphors experience significant brightness deterioration when exposed to high-energy excitation sources, necessitating the development of phosphors with enhanced stability and emission characteristics, particularly in the red and near-infrared regions.
Innovation Solution
A phosphor with a specific inorganic compound structure, represented by Sr6x(Si, Al)27-12x(O, N)31-6xLi3y, where 0.4≤x≤0.8 and 0≤y≤0.35, exhibiting a hexagonal crystal system and belonging to the P63 space group, which maintains high emission intensity and stability even under excitation.
Engineering Contradictions & Design Principles
Engineering 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 over time
Solution Approach 1:
The patent changes the chemical composition parameters of the phosphor by incorporating nitrogen into the crystal structure (forming sialon or oxynitride phases) and optimizing the Si/Al ratio and oxygen/nitrogen content. This compositional modification fundamentally alters the phosphor's resistance to high-energy excitation, maintaining luminance while enabling efficient light emission under UV or blue LED excitation.
Solution Approach 2:
The patent creates composite phosphor materials by combining multiple elements (Si, Al, O, N) in specific ratios to form sialon or oxynitride crystal structures. These composite materials integrate the beneficial properties of both oxide and nitride phases, achieving high emission intensity combined with superior brightness stability under prolonged excitation.
2Illumination intensity
If the crystal structure is modified to improve emission characteristics, then the emission wavelength can be tuned, but the manufacturing complexity increases
Solution Approach 1:
The patent employs parameter changes within a established crystal system (sialon or oxynitride) rather than developing entirely new crystal structures. By adjusting continuous parameters such as Si/Al ratio, oxygen/nitrogen content, and activating ion concentration, the emission wavelength can be tuned across different regions (blue, green, yellow, red) using conventional ceramic processing techniques, avoiding the need for complex new synthesis methodologies.
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 achieves high emission intensity in the red and near-infrared regions, suitable for applications in white LEDs, illuminating devices, and infrared lighting, with minimal brightness deterioration when exposed to excitation sources.
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
Data Source
AI summary
Provided are a phosphor emitting light having a wavelength of 600 nm or more in the red-to-nearinfrared range when irradiated with visible light or ultraviolet light; a method for producing same; a light emitting element using same; and a light emitting device using same. The phosphor includes an inorganic compound including A element, M element, D element, E element (A is at least one element selected from the group of Mg, Ca, Sr and Ba; M is at least one element selected from the group of Mn, Eu, Ce, Nd, Tb, Dy, Ho, Er, Tm and Yb; D is Si and/or Al; and E is O and/or N) and, if necessary, G element (G is Li), and represented by (A, M)aDdEeGg, (atomic fraction parameters a, d, e and g satisfy 2.4≤a≤4.8, 17.4≤d≤22.2, 26.2≤e≤28.6 and 0≤g≤3).