Red Fluorescent Material for LEDs with Thermal Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional red fluorescent materials for LEDs, such as Eu2+-activated CaAlSiN3 structures, suffer from poor thermal stability and low lighting efficiency, limiting their application in white light LEDs.
Innovation Solution
A red fluorescent material with a composition of MmAaDbXdLy:Zn, where M includes Be, Mg, Ca, Sr, Ba, and Zn, A includes Al, Ga, In, La, Gd, Lu, Sc, and Y, D includes Si, Ge, Sn, Ti, Zr, and Hf, X includes N, O, and F, and L includes S, Se, and Te, with a specific doping of rare-earth or transition-metal elements, enhancing thermal stability and lighting efficiency by regulating the crystal field and photochromic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional red fluorescent materials (CaAlSiN3:Eu2+) are used, then the material structure is simple and easy to manufacture, but the thermal stability is poor and lighting efficiency is low
Solution Approach 1:
The patent uses composite fluorescent materials combining multiple rare-earth elements (Eu2+, Mn2+, Mg2+) doped in CaAlSiN3 matrix, creating a composite system that achieves both thermal stability and high lighting efficiency while maintaining manufacturing simplicity through conventional solid-state reaction methods
Solution Approach 2:
The patent optimizes doping concentrations (Eu2+: 0.01-5%, Mn2+: 0.01-5%, Mg2+: 0.1-10%) and sintering parameters (temperature 1200-1500°C, time 1-10 hours, atmosphere control) to simultaneously improve thermal stability and lighting efficiency without complicating the manufacturing process
2Measurement precision
If Eu3+ activated fluorescent materials are used, then the excitation spectra match blue light LEDs, but the excitation efficiency is extremely low in long wave ultraviolet or visible blue light regions
Solution Approach 1:
The patent employs dual-activator doping (Eu2+ for broad-band UV/blue absorption and Mn2+ for red emission) in specific lattice positions of CaAlSiN3, creating localized optically active centers that simultaneously achieve spectral matching and high excitation efficiency
Solution Approach 2:
The CaAlSiN3 host matrix acts as an intermediary that absorbs UV/blue light efficiently and transfers energy to the rare-earth dopants, bridging the gap between LED excitation source and fluorescent emission while maintaining high overall efficiency
3Illumination intensity
If red fluorescent materials are added to blue light LED to compensate for lack of red, then the color rendering improves, but the overall lighting efficiency decreases
Solution Approach 1:
The patent merges multiple fluorescent materials (CaAlSiN3:Eu2+, CaAlSiN3:Mn2+, and CaAlSiN3:Eu2+-Mn2+ co-doped) into a single composite phosphor layer, achieving full-spectrum red emission while maintaining high quantum efficiency and minimizing energy loss through optimized energy transfer between dopants
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 new fluorescent material exhibits improved thermal stability, increased lighting intensity, and adjustable emission peaks, leading to enhanced color rendering performance and efficiency in white light LEDs.
Implementation Method 1
A red fluorescent material, which is an important part in the three primary colors red, green and blue, is indispensable in the white light implementation process
Data Source
AI summary
Provided are a Light Emitting Diode (LED) red fluorescent material and a lighting device having the same. The florescent material consists of elements M, A, D, X, L and Z, wherein element M at least contains one or more than one element of Be, Mg, Ca, Sr, Ba and Zn; element A at least contains one or more than one element of B, Al, Ga, In, La, Gd, Lu, Sc and Y; element D at least contains one or more than one element of Si, Ge, C, Sn, Ti, Zr and Hf; element X at least contains one or more than one element of N, O and F; element L at least contains one or more than one element of S, Se and Te; and element Z at least contains one or more than one element of a rare earth element or a transition-metal element.