Green-Emitting Phosphor Composition for Pure Green LED Displays
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Solution Overview
Problem
Current display device technology relies on liquid crystal displays (LCDs) that lack improved color gamut, energy efficiency, and compact size, necessitating the development of new green-emitting phosphors that can efficiently absorb blue radiation and provide high quantum efficiency.
Innovation Solution
The development of green-emitting phosphors with specific chemical compositions, such as [Ba1−a−bSraCab]x[Mg,Zn]y(UO2)z([P,V]O4)2(x+y+z)/3 and [Ba,Sr,Ca,Mg,Zn]p(UO2)q[P,V]rO(2p+2q+5r)/2, which absorb near-UV or blue radiation and emit light in a narrow band between 500 nm and 550 nm, particularly from 515 nm to 525 nm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional green phosphor β-SiAlON:Eu2+ is used, then the display device can be manufactured with existing technology, but the emission peak wavelength is 534 to 540 nm which is greenish yellow rather than pure green
Solution Approach 1:
The patent changes the chemical composition parameters of the phosphor by incorporating uranium (UO2) and rare earth elements (Nd, Pr, Dy) into the host lattice, shifting the emission peak from 534-540 nm (greenish yellow) to 500-550 nm (pure green), specifically achieving 515-525 nm emission wavelength
Solution Approach 2:
The patent creates a composite phosphor material with specific host lattice structure containing UO2 and rare earth elements, combining multiple elements to achieve both pure green emission and high quantum efficiency while maintaining manufacturability
2Illumination intensity
If the color gamut is improved by using new phosphors, then the display quality is enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent optimizes the concentration ratios of UO2 and rare earth elements in the phosphor composition to achieve narrow emission bandwidth and pure green color, expanding the color gamut while establishing clear compositional ranges for manufacturability
3Use of energy by moving object
If the quantum efficiency is increased by optimizing phosphor composition, then the energy consumption is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent establishes specific compositional ranges and ratios for UO2 and rare earth elements that optimize quantum efficiency by enhancing blue light absorption and green light emission, while providing clear guidance for manufacturing control
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
These phosphors significantly improve the color gamut of display devices, achieving high luminosity and efficient energy use, while providing a pure green emission that enhances display quality.
Implementation Method 1
green-emitting phosphors... which absorb near-UV or blue radiation and emit light in a narrow band between 500 nm and 550 nm
Data Source
AI summary
Green-emitting phosphors are useful in devices including an LED light source radiationally coupled and/or optically coupled to the phosphors, which are selected from[Ba1−a−bSraCab]x[Mg,Zn]y(UO2)z([P,V]O4)2(x+y+z)/3,where 0≤a≤1, 0≤b≤1, 0.75≤x≤1.25, 0.75≤y≤1.25, 0.75≤z≤1.25; and[Ba,Sr,Ca,Mg,Zn]p(UO2)q[P,V]rO(2p+2q+5r)/2,where 2.5≤p≤3.5, 1.75≤q≤2.25, 3.5≤r≤4.5.