Halide Phosphor for High-Efficiency White LEDs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current white LEDs using YAG phosphors have inadequate luminous efficiency and are not suitable for general lighting, necessitating the development of novel phosphors with improved luminescence performance.
Innovation Solution
A phosphor composition containing rare earth, silicon, alkaline-earth metal, halogen, and oxygen, represented by the formula aLn2O3.MO.bM′2O3.fSiO2.cAXe:dR, which can be excited by ultraviolet, purple, or blue LEDs, offering high conversion efficiency and chemical stability, and a simple preparation method involving high-temperature baking and post-treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If YAG phosphor is used in white LEDs, then the LED can be manufactured with current technology, but the luminous efficiency is inadequate and not suitable for general lighting
Solution Approach 1:
The patent changes the chemical composition parameters of the phosphor material by incorporating specific ratios of rare earth elements (Y, La, Gd), alkaline-earth metals (Mg, Ca, Sr, Ba), and halogens (F, Cl) to optimize luminescence properties. The general formula aLn2O3.MO.bM′2O3.fSiO2.cAXe:dR allows systematic parameter adjustment to achieve high luminous efficiency while maintaining stability for general lighting applications.
Solution Approach 2:
The patent creates a composite phosphor material combining multiple elements (rare earth, alkaline-earth metal, silicon, halogen, oxygen, aluminum, or gallium) with specific structural components (Ln2O3, MO, M′2O3, SiO2, AXe) to achieve synergistic effects that improve both luminous efficiency and operational reliability beyond what single-component YAG phosphor can provide.
2Use of energy by moving object
If novel phosphors are developed to improve luminous efficiency, then energy conversion efficiency increases, but the chemical stability may be compromised
Solution Approach 1:
The patent assigns different functional roles to specific components within the phosphor structure: rare earth elements (Ln) provide the luminescence centers for high conversion efficiency, while alkaline-earth metals (M, M′) and halogens (X) stabilize the crystal structure. This local functional differentiation allows simultaneous optimization of both conversion efficiency and chemical stability.
Solution Approach 2:
The patent incorporates oxygen and halogen elements (F, Cl) into the phosphor structure to create a chemically stable, inert environment that protects the luminescent rare earth centers from degradation while maintaining high conversion efficiency. The oxide and halide components form stable bonds that prevent unwanted chemical reactions.
3Loss of energy
If complex phosphor compositions are used to achieve high luminous efficiency, then luminescence performance improves, but the manufacturing complexity increases
Solution Approach 1:
The patent designs a universal phosphor system with a general formula aLn2O3.MO.bM′2O3.fSiO2.cAXe:dR that can accommodate multiple rare earth elements, alkaline-earth metals, and halogens. This universal structure allows optimization of luminous efficiency through element selection while maintaining a consistent manufacturing approach, reducing overall complexity despite the multi-element composition.
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 luminous efficiency and broadband visible light emission, enabling the production of white LEDs with improved efficiency and stability, suitable for general lighting applications.
Implementation Method 1
A phosphor according to one aspect of the invention contains, for example, rare earth, silicon, alkaline-earth metal, halogen, and oxygen, as well as aluminum or gallium... can be excited by ultraviolet, purple or blue LED's
Data Source
AI summary
A phosphor can be excited by UV, purple or blue light LED, its preparation method, and light emitting devices incorporating the same. The phosphor contains rare earth, silicon, alkaline-earth metal, halogen, and oxygen, as well as aluminum or gallium. Its General formula of is aLn2O3.MO.bM′2O3.fSiO2.cAXe:dR, wherein Ln is at least one metal element selected from a group consisting of Sc, Y, La, Pr, Nd, Gd, Ho, Yb and Sm; M is at least one metal element selected from a group consisting of Ca, Sr and Ba; M′ is at least one metal element selected from Al and Ga; A is at least one metal element selected from a group consisting of Li, Na, K, Mg, Ca, Sr and Ba; X is at least one element selected from F and Cl; R is at least one metal element selected from a group consisting of Ce, Eu, Tb and Mn; 0.01≦a≦2, 0.35≦b≦4, 0.01≦c≦1, 0.01≦d≦0.3, 0.01≦f≦3, 0.6≦e≦2.4. The phosphor has broad emitting range, high efficiency, better uniformity and stability. A light emitting device is obtained by incorporating the phosphor into a UV, purple or blue light emitting device.