Silicate-Based Orange Phosphors for White LED Efficiency
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Solution Overview
Problem
Existing orange phosphors in white LED systems have limited conversion efficiency from radiation sources to orange light, affecting color temperature and rendering index stability.
Innovation Solution
Development of Eu2+-activated silicate-based compounds with specific divalent cations, anions, and halogen dopants, such as (Sr,A1)x(Si,A2)(O,A3)2+x:Eu2+, which emit visible light with a peak wavelength greater than 565 nm, optimized through sol-gel, solid reaction, and co-precipitation methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If existing orange phosphors are used in white LED systems, then the system can provide orange light emission, but the conversion efficiency from radiation source to orange light is limited
Solution Approach 1:
The patent changes the chemical composition parameters of the phosphor material by incorporating specific divalent cations (Mg, Ca, Ba, Zn) in controlled ratios within the silicate structure. This compositional parameter optimization enables enhanced conversion efficiency while maintaining color stability, directly resolving the technical contradiction between energy loss and reliability
Solution Approach 2:
The patent creates a composite phosphor material combining multiple elements (Sr, A1, Si, A2, O, A3, Eu) in a structured silicate compound. This composite approach allows synergistic effects where the combination of divalent cations with europium activator in the silicate matrix achieves both high conversion efficiency and stable color properties, resolving the contradiction between energy loss and reliability
2Illumination intensity
If Eu2+-activated silicate-based compounds with specific compositions are developed, then emission intensity and peak wavelengths are enhanced, but the manufacturing process complexity increases
Solution Approach 1:
The patent employs sol-gel method where phosphor precursors are prepared in advance as homogeneous solutions or gels before final sintering. This preliminary action ensures uniform distribution of Eu2+ activator and divalent cations throughout the silicate matrix, achieving high emission intensity while simplifying the overall manufacturing process by preventing aggregation and ensuring consistent composition
Solution Approach 2:
The patent uses sol-gel chemistry as an intermediary process that transforms simple precursor solutions into complex phosphor structures. The sol-gel method acts as a mediator that facilitates uniform incorporation of multiple elements (Sr, A1, Si, A2, O, A3, Eu) into the silicate matrix through controlled hydrolysis and condensation reactions, achieving high emission intensity without requiring complex direct synthesis procedures
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 phosphors exhibit enhanced emission intensity and longer peak wavelengths, improving color rendering and stability in white LED systems when excited by UV, blue, or yellow radiation sources.
Implementation Method 1
Eu2+-activated silicate-based compounds... emit visible light with a peak wavelength greater than 565 nm, optimized through sol-gel, solid reaction, and co-precipitation methods
Implementation Method 2
optimized through sol-gel, solid reaction, and co-precipitation methods
Implementation Method 3
optimized through sol-gel, solid reaction, and co-precipitation methods
Data Source
AI summary
Novel orange phosphors are disclosed having the comprise silicate-based compounds having the formula (Sr,A1)x,(Si,A2)(O,A3)2+x:Eu2+, where A1 is at least one divalent cation (a 2+ ion) including Mg, Ca, Ba, or Zn, or a combination of 1+ and 3+ cations; A2 is a 3+, 4+, or 5+ cation, including at least one of B, Al, Ga, C, Ge, P; A3 is a 1−, 2−, or 3− anion, including F, Cl, and Br; and x is any value between 2.5 and 3.5, inclusive. The formula is written to indicate that the A1 cation replaces Sr; the A2 cation replaces Si, and the A3 anion replaces O. These orange phosphors are configured to emit visible light having a peak emission wavelength greater than about 565 nm. They have applications in white LED illumination systems, plasma display panels, and in orange and other colored LED systems.