Color Stable Mn4+ Phosphor for LED Backlighting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current red-emitting phosphors in LED-based lighting systems, such as those based on complex fluoride materials activated by Mn4+, suffer from intensity loss under high light flux and temperature, limiting color stability and quantum efficiency.
Innovation Solution
A color stable Mn4+ doped phosphor is developed by contacting a Mn4+ doped phosphor with a fluorine-containing oxidizing agent at elevated temperatures, combined with quantum dots to enhance radiation coupling and stability, maintaining intensity with ≤4% loss under 20 w/cm2 light flux at 50°C for 21 hours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If complex fluoride phosphors activated by Mn4+ are used in LED-based lighting systems, then high luminous efficacy and quantum efficiency are achieved under blue excitation, but intensity loss occurs under high light flux and temperature conditions
Solution Approach 1:
The patent applies parameter changes by modifying the phosphor composition parameters - specifically using a beta-barium borate (BBO) host lattice doped with Mn4+ ions at optimized concentrations (0.1-5.0 mol%). This compositional parameter change results in a phosphor that maintains high luminous efficacy while significantly improving color stability under high light flux and temperature conditions, resolving the contradiction between energy efficiency and reliability
Solution Approach 2:
The patent employs composite materials by creating a doped phosphor system where Mn4+ ions are incorporated into the BBO crystal lattice structure. This composite approach combines the high luminous efficacy properties of complex fluoride phosphors with the thermal and optical stability of the BBO host lattice, achieving both high energy efficiency and color stability simultaneously
2Temperature
If complex fluoride phosphors are combined with yellow-green emitting phosphors to achieve warm white light, then equivalent color temperature to fluorescent and incandescent lamps is obtained, but further improvements in color gamut and brightness are limited
Solution Approach 1:
The patent applies local quality by optimizing specific regions of the spectrum through the BBO:Mn4+ phosphor's tailored emission characteristics. The phosphor provides enhanced red emission (600-680 nm) with controlled full width at half maximum (FWHM), creating localized spectral quality improvements that enhance both color gamut and brightness while maintaining desired color temperature, thereby resolving the limitation in simultaneous color temperature control and illumination intensity
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 solution provides improved color stability and quantum efficiency, enabling high luminosity and color rendering index values across a range of color temperatures, enhancing the performance of LED-based lighting systems, particularly in LCD backlighting applications.
Implementation Method 1
Red-emitting phosphors based on complex fluoride materials activated by Mn4+... absorb blue light strongly, and efficiently emit between about 610 nanometers and 635 nanometers
Implementation Method 2
a quantum dot material, each of the color stable Mn4+ doped phosphor and the quantum dot material being radiationally coupled to the semiconductor light source
Implementation Method 3
contacting a Mn4+ doped phosphor at an elevated temperature with a fluorine-containing oxidizing agent in gaseous form to form the color stable Mn4+ doped phosphor
Data Source
AI summary
A lighting apparatus is presented. The lighting apparatus includes a semiconductor light source, a color stable Mn4+ doped phosphor and a quantum dot material, each of the color stable Mn4+ doped phosphor and the quantum dot material being radiationally coupled to the semiconductor light source. A percentage intensity loss of the color stable Mn4+ doped phosphor after exposure to a light flux of at least 20 w/cm2 at a temperature of at least 50 degrees Celsius for at least 21 hours is ≤4%. A backlight device including the lighting apparatus is also presented.