Wavelength Conversion Sintered Body Gallium Control
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Solution Overview
Problem
Existing wavelength conversion members in light emitting devices, such as those using α-SiAlON fluorescent materials, suffer from insufficient heat radiation and adverse effects from glass components, leading to reduced light emission intensity and altered chromaticity due to gallium oxide inhibition of aluminum oxide sintering and reaction with the fluorescent material.
Innovation Solution
A method for producing a wavelength conversion sintered body involving a mixture of α-SiAlON fluorescent material, aluminum oxide particles, and optionally rare earth aluminate fluorescent material, with a gallium content of 15 ppm by mass or less, primary calcined at temperatures between 1370°C and 1600°C to achieve high relative density and desired light emission intensity without sintering inhibition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If glass components are used in the wavelength conversion member, then the sintering process can be simplified, but the glass component adversely affects the light emission of the fluorescent material and reduces heat radiation efficiency
Solution Approach 1:
The patent removes glass components from the wavelength conversion member composition, using only fluorescent material and sintering aid particles. This extraction eliminates the adverse effects of glass on light emission while maintaining simplified manufacturing through the sintering aid approach.
Solution Approach 2:
The patent changes the compositional parameters by eliminating glass and instead using specific sintering aid particles with controlled content (0.1-10 wt%). This parameter change achieves both simplified manufacturing and improved light emission by avoiding glass-related degradation mechanisms.
2Ease of manufacture
If gallium oxide is present in the mixture, then the sintering process may be facilitated, but it inhibits aluminum oxide sintering and reacts with the fluorescent material, reducing light emission intensity and altering chromaticity
Solution Approach 1:
The patent removes gallium oxide from the mixture composition entirely. By eliminating this problematic substance, the patent prevents both the sintering inhibition of aluminum oxide and the unwanted reactions with fluorescent material that would alter chromaticity.
Solution Approach 2:
The patent introduces sintering aid particles as an intermediary substance to facilitate sintering without the harmful effects of gallium oxide. These particles act as a benign mediator that promotes densification while preserving the fluorescent material's optical properties.
3Illumination intensity
If the fluorescent material is used without sufficient heat radiation capability, then the light emission intensity decreases due to heat accumulation, but adding heat radiation components may affect the sintering process
Solution Approach 1:
The sintering aid particles serve multiple functions simultaneously: they facilitate sintering by promoting densification and also improve heat radiation capability of the final product. This multi-functionality eliminates the need for separate heat radiation additives that would complicate the sintering process.
Solution Approach 2:
The patent changes the thermal properties of the wavelength conversion member by incorporating sintering aid particles with good heat radiation characteristics. This parameter change improves heat dissipation and light emission intensity while maintaining sintering process control through optimized particle content.
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 method results in a wavelength conversion sintered body with improved heat radiation, maintained crystal structure of the α-SiAlON fluorescent material, and enhanced light emission intensity, providing desired chromaticity and mechanical strength.
Implementation Method 1
a fluorescent material such as a rare earth aluminate fluorescent material or an α-SiAlON fluorescent material contained in a wavelength conversion member
Implementation Method 2
primary calcining the molded body at a temperature in a range of 1,370° C. or more and 1,600° C. or less to obtain a first sintered body
Data Source
AI summary
Provided is a method for producing a wavelength conversion sintered body that emits light under irradiation of excitation light. The method for producing a wavelength conversion sintered body includes: preparing a molded body obtained by molding a mixture containing an α-SiAlON fluorescent material and aluminum oxide particles and having a content of Ga of 15 ppm by mass or less; and primary calcining the molded body at a temperature in a range of 1,370° C. or more and 1,600° C. or less to obtain a first sintered body.