Lu3Al5O12:Ce Phosphor for High-Temperature White Light Sources
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Solution Overview
Problem
Existing phosphors used in semiconductor light emitting devices for white light sources, such as YAG:Ce, face challenges in achieving high luminance and color rendering properties, especially in blue-green light emission, and suffer from decreased light emission luminance at high temperatures.
Innovation Solution
A phosphor with the chemical formula Lu(3-x-z)MgxZnyAl(5-y)O12:Cez is developed, where specific ranges of x and y indices optimize the light emission peak wavelength between 500 nm and 520 nm, enhancing color rendering and maintaining luminance at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional phosphors such as YAG:Ce are used to generate white light, then the light source achieves high luminance, but the color rendering property deteriorates due to insufficient blue-green light emission
Solution Approach 1:
The patent uses a composite phosphor system combining YAG:Ce (yellow emitter) with Lu3Al5O12:Ce (blue-green emitter) in specific ratios. This composite approach allows simultaneous achievement of high luminance from YAG:Ce and improved color rendering from Lu3Al5O12:Ce, resolving the contradiction between brightness and color quality.
Solution Approach 2:
The patent introduces a second phosphor material Lu3Al5O12:Ce with specific emission characteristics (peak wavelength 480-520 nm) to supplement the blue-green region. This targeted addition of specific emission properties to填补 the spectral gap improves color rendering without compromising overall luminance.
2Reliability
If phosphors are used to improve color rendering property, then blue-green light emission is enhanced, but light emission luminance decreases at high temperatures
Solution Approach 1:
The patent optimizes the composition parameters of Lu3Al5O12:Ce, specifically controlling Ce doping concentration (0.01≤z≤0.03) and stoichiometric ratios (x and y parameters), to achieve thermal stability. This parameter optimization ensures the phosphor maintains high emission luminance even at elevated operating temperatures while preserving color rendering properties.
Solution Approach 2:
The dual-phosphor composite system provides thermal compensation effects. YAG:Ce maintains stable yellow emission at high temperatures, while optimized Lu3Al5O12:Ce contributes blue-green emission with improved thermal stability, together maintaining overall luminance and color rendering under thermal stress.
3Reliability
If multiple phosphors are combined to achieve high color rendering, then blue-green light is supplemented, but the device structure becomes more complex
Solution Approach 1:
The Lu3Al5O12:Ce phosphor serves multiple functions: it emits blue-green light to improve color rendering, maintains thermal stability for high-temperature operation, and can be integrated into existing LED structures. This multi-functionality reduces the need for additional specialized components, simplifying overall device design despite using multiple phosphors.
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 achieves a high color rendering property with minimal luminance decrease at high temperatures, making it suitable for high-luminance white light sources and laser excitation projectors, and is integrated into semiconductor light emitting devices for improved performance.
Implementation Method 1
A phosphor according to an aspect of the present disclosure absorbs a bluish excitation light and emits blue-greenish fluorescence
Implementation Method 2
a technique using a semiconductor light emitting element represented by a gallium nitride (GaN)-based blue light emitting diode and a phosphor such as YAG:Ce in combination
Data Source
AI summary
A phosphor is represented by a chemical formula of Lu(3-x-z)MgxZnyAl(5-y)O12:Cez, in which in a case where z is in a range of 0.01≤z≤0.03, x and y respectively satisfy 0<x≤1.4 and 0<y≤1.4, in a case where z is in a range of 0.03<z≤0.06, x and y respectively satisfy y<0.2 and 0.1≤x≤1.4, x<0.2 and 0.1≤y≤1.4, or x=0.2 and y=0.2, in a case where z is in a range of 0.06<z≤0.09, x and y respectively satisfy y<0.2 and 0.1≤x<1.4, or x<0.2 and 0.1≤y<1.4, and in a case where z is in a range of 0.09<z≤0.12, x and y respectively satisfy y<0.2 and 0.1≤x<0.9, or x<0.2 and 0.1≤y<0.9.