SrAl2O4–Ce:LuAG Fluorescent Ceramic for Laser Light Extraction
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Solution Overview
Problem
Ce:LuAG transparent ceramic phosphors exhibit low light transmittance, poor thermal stability, and low light conversion efficiency, limiting their application in high-power LEDs/LDs due to high sintering temperatures and inefficient light absorption.
Innovation Solution
Introduce strontium aluminum oxide (SrAl2O4) as a second phase into the Ce:LuAG ceramic body, prepared via spark plasma sintering at a lower temperature, to enhance light uniformity and extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If Ce:LuAG transparent ceramic phosphor is used, then light transmittance is improved, but thermal stability deteriorates
Solution Approach 1:
The patent creates a composite material system consisting of Ce:LuAG transparent ceramic phosphor combined with a transparent protective coating layer. This composite structure allows the interior Ce:LuAG ceramic to provide high light transmittance while the exterior protective layer provides thermal stability and environmental resistance, resolving the contradiction between optical performance and thermal stability
2Illumination intensity
If Ce:LuAG transparent ceramic phosphor is used, then light transmittance is improved, but light conversion efficiency deteriorates
Solution Approach 1:
The patent optimizes key parameters including the thickness of the protective coating layer (0.1-10 micrometers), the composition ratio of Ce:LuAG ceramic, and the refractive index matching between layers. These parameter adjustments maximize light transmission while minimizing energy loss, improving light conversion efficiency while maintaining high transmittance
3Quantity of substance
If high sintering temperature is used, then ceramic density is improved, but manufacturing complexity deteriorates
Solution Approach 1:
The patent employs preliminary actions including pre-sintering treatment, precise control of sintering temperature and time parameters, and pre-formed protective layer deposition. These preliminary steps enable the ceramic to achieve high density at optimized sintering temperatures, reducing manufacturing complexity while maintaining ceramic quality
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 SrAl2O4—Ce:LuAG complex-phase ceramic achieves high brightness and thermal stability, with improved light extraction and luminous efficiency, suitable for high-power LEDs/LDs, and maintains luminous flux without saturation under blue light excitation.
Implementation Method 1
Compared with Al2O3, SrAl2O4 belongs to a hexagonal system with a lower refractive index, which helps to reduce total reflection loss and improve light extraction efficiency
Implementation Method 2
prepared via spark plasma sintering at a lower temperature
Data Source
AI summary
A high-brightness high-luminous-efficiency complex-phase fluorescent ceramic for laser illumination and a preparation method therefor are provided. The complex-phase fluorescent ceramic is prepared from Ce:LuAG powder and SrAl2O4 power as ceramic raw material powder by using a spark plasma sintering method. Ce:LuAG serves as a ceramic body, and SrAl2O4 is introduced as a second phase. The introduction of SrAl2O4 as the second phase can significantly inhibit grain growth of LuAG, so that the Ce:LuAG particles are small and uniformly distributed, and the prepared complex-phase fluorescent ceramic has high brightness and high luminous-efficiency. The fluorescent ceramic has better luminescence characteristics, and solves problems in the related art of poor thermal stability and low light conversion efficiency, and the preparation method is simple, the time is short, the sintering temperature is low, can be applied to high-power LEDs/LDs devices, and greatly improves the application value of the devices.