Red Phosphor Composition for Narrow-Band LED Color Conversion
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Solution Overview
Problem
Existing red phosphors for light-emitting devices have unclear emission intensity and broad full widths at half maximum, leading to inefficient conversion efficiency and color rendering.
Innovation Solution
A phosphor with a crystal phase represented by specific compositions, such as RexMAaMBbMCcNdXe, that includes a minimum reflectance of 20% or more in a prescribed wavelength region from the emission peak to 800 nm, enhancing emission intensity and conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional red phosphors (KSF, S/CASN) are used, then red light emission is achieved, but emission intensity is insufficient and conversion efficiency is poor
Solution Approach 1:
The patent changes the chemical composition parameters of the phosphor by incorporating specific ratios of Al, Si, and Ga elements in the formula RexMAaMBbMCcNdXe, optimizing the crystal structure to enhance emission intensity and conversion efficiency simultaneously
Solution Approach 2:
The patent creates a composite phosphor material combining multiple elements (RexMAaMBbMCcNdXe) with complementary properties, where the synergistic interaction between Al, Si, and Ga components achieves superior emission characteristics that individual elements cannot provide
2Illumination intensity
If phosphors with broad FWHM (80-90 nm) are used, then red light emission is achieved, but color rendering is poor due to inclusion of low luminous efficiency wavelengths
Solution Approach 1:
The patent optimizes the compositional parameters (a, b, c, d, e, x) in the phosphor formula to control the emission spectrum shape, achieving narrow FWHM (50-70 nm) that concentrates emission in the high luminous efficiency red region while maintaining good color rendering
3Illumination intensity
If KSF phosphor is used, then red light emission is achieved, but harm to humans and environment is caused
Solution Approach 1:
The patent replaces the harmful but effective KSF phosphor with an environmentally benign alternative phosphor (RexMAaMBbMCcNdXe) that achieves comparable or superior performance without toxicity, prioritizing safety while maintaining functionality
Solution Approach 2:
The patent changes the chemical composition to eliminate harmful elements by substituting KSF's toxic components with non-toxic Al, Si, and Ga-based compounds that maintain the desired red emission properties
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 proposed solution provides light-emitting devices with improved color rendering, color reproducibility, and conversion efficiency, making them suitable for various applications including illumination, image display, and vehicle indicators.
Implementation Method 1
a phosphor arranged on an LED chip that emits light in a blue or near ultraviolet wavelength
Data Source
AI summary
A phosphor having a favorable emission peak wavelength, narrow full width at half maximum, and/or high emission intensity is provided. Additionally, a light-emitting device, an illumination device, an image display device, and/or an indicator lamp for a vehicle having favorable color rendering, color reproducibility and/or favorable conversion efficiency are provided. The present invention relates to a phosphor including a crystal phase having a composition represented by a specific formula, and having a minimum reflectance of 20% or more in a specific wavelength region, in which the specific wavelength region is from the emission peak wavelength of the phosphor to 800 nm, and a light-emitting device comprising the phosphor.