Phosphor Composition for Stable LED Color Rendering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current conversion LEDs for general lighting and backlighting face issues with fluctuations in color rendering due to variations in semiconductor chip peak wavelengths, leading to inconsistent optical properties, and existing phosphors like yttrium aluminum garnet and β-SiAlON have limitations in efficiency and production costs.
Innovation Solution
A phosphor with a specific molecular formula (MA)a(MB)b(MC)c(MD)d(TA)e(TB)f(TC)g(TD)h(TE)i(TF)j(XA)k(XB)l(XC)m(XD)n, where MA, MB, MC, MD, TA, TB, TC, TD, TE, TF, XA, XB, XC, and XD are selected from specific groups of elements, and the phosphor contains activators like Eu, Ce, Yb, and Mn, allowing for controlled peak wavelength and full width at half maximum, enhancing stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional phosphors like yttrium aluminum garnet are used, then broad emission coverage is achieved, but efficiency is reduced and production costs increase
Solution Approach 1:
The patent changes the chemical composition parameters of the phosphor by incorporating specific ratios of Al, Ga, In, Si, and P elements, along with activators like Eu, Ce, Yb, and Mn. This compositional parameter optimization achieves narrowband emission with high quantum efficiency while avoiding the need for expensive production equipment required by conventional phosphors
Solution Approach 2:
The patent creates a composite phosphor material combining multiple elements (Al, Ga, In, Si, P) with rare earth activators (Eu, Ce, Yb, Mn) in specific ratios. This composite structure enables simultaneous achievement of narrow emission bandwidth, high internal quantum efficiency, and cost-effective production without requiring extreme manufacturing conditions
2Reliability
If semiconductor chips are sorted with narrow tolerances to avoid fluctuations, then quality of multi-chip devices is improved, but manufacturing complexity and costs increase
Solution Approach 1:
The patent stabilizes the phosphor's emission characteristics by optimizing its chemical composition and activator content, making the phosphor less sensitive to semiconductor chip wavelength variations. This reduces the need for stringent binning tolerances while maintaining device quality
Solution Approach 2:
The phosphor acts as an intermediary that converts blue primary radiation to broader spectral ranges with stable color rendering. By optimizing the phosphor's conversion characteristics, the system becomes more tolerant of semiconductor chip variations, reducing the need for complex sorting processes
3Illumination intensity
If β-SiAlON phosphor is used for narrowband emission, then color space coverage is improved, but internal and external quantum efficiency are reduced
Solution Approach 1:
The patent develops a composite phosphor material combining AlGaInSiP host lattice with multiple rare earth activators (Eu, Ce, Yb, Mn). This composite structure achieves narrowband emission with full width at half maximum of less than 60 nm while maintaining high internal and external quantum efficiency, overcoming the efficiency limitations of β-SiAlON
Solution Approach 2:
The patent optimizes the local chemical environment around the activator ions by controlling the host lattice composition (Al, Ga, In, Si, P ratios). This local environmental optimization enhances the quantum efficiency of the activators while maintaining narrow emission bandwidth, achieving both color purity and efficiency
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 provides stable and efficient conversion of primary radiation to secondary radiation with narrowband emission, improving color rendering and reducing production costs by offering adaptable properties for various applications, including 'color on demand' scenarios.
Implementation Method 1
A phosphor provides stable and efficient conversion of primary radiation to secondary radiation with narrowband emission
Data Source
AI summary
A lighting device is specified. The lighting device comprises a phosphor having the general molecular formula (MA)a(MB)b(MC)c(MD)d(TA)e(TB)f(TC)g(TD)h(TE)i(TF)j(XA)k(XB)l(XC)m(XD)n:E. In this case, MA is selected from a group of monovalent metals, MB is selected from a group of divalent metals, MC is selected from a group of trivalent metals, MD is selected from a group of tetravalent metals, TA is selected from a group of monovalent metals, TB is selected from a group of divalent metals, TC is selected from a group of trivalent metals, TD is selected from a group of tetravalent metals, TE is selected from a group of pentavalent elements, TF is selected from a group of hexavalent elements, XA is selected from a group of elements which comprises halogens, XB is selected from a group of elements which comprises O, S and combinations thereof, XC=N and XD=C and E=Eu, Ce, Yb and/or Mn. The following furthermore hold true: a+b+c+d=t; e+f+g+h+i+j=u; k+l+m+n=v; a+2b+3c+4d+e+2f+3g+4h+5i+6j−k−2l−3m−4n=w; 0.8≤t≤1; −3.5≤u≤4; 3.5≤v≤4; (−0.2) w≤0.2 and 0≤m<0.875 v and/or v≥l>0.125 v.