Sintered Body Light Extraction via Molar Ratio Control
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Solution Overview
Problem
Current methods for producing sintered bodies with wavelength conversion capabilities struggle to achieve desired color emission, high luminous flux, and efficient light extraction while maintaining illumination efficiency.
Innovation Solution
A method involving a raw material mixture of oxide particles containing rare earth elements, Ce, Al, Ga, and optionally Sc, calcined at specific temperatures to form a sintered body with a rare earth aluminate crystal phase and aluminum oxide phase, optimizing molar ratios and specific surface areas for enhanced light emission and extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional sintering methods are used to produce wavelength conversion members, then the production process is simple, but the light extraction efficiency and luminous flux are insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the sintering temperature (1300-1800°C) and duration (1-12 hours) to optimize the formation of rare earth aluminate crystal phases. By adjusting these thermal parameters, the sintered body achieves high luminous flux and light extraction efficiency while maintaining a relatively simple production process. The specific temperature range facilitates complete sintering and desired crystal phase formation without excessive complexity.
Solution Approach 2:
The patent employs composite materials by combining multiple oxide particles (rare earth elements, Ce, Al, Ga, Sc) in specific molar ratios before sintering. This composite approach creates a sintered body with multiple crystal phases (rare earth aluminate and aluminum oxide) that work synergistically to achieve high luminous flux and light extraction efficiency, resolving the contradiction between simple production and high productivity.
2Productivity
If the sintering temperature is increased to improve light emission efficiency, then the luminous flux increases, but the energy consumption and risk of overheating increase
Solution Approach 1:
The patent optimizes the sintering temperature parameter to a specific range (1300-1800°C) that balances energy consumption with luminous flux generation. This parameter optimization ensures complete sintering and desired crystal phase formation at the lowest necessary temperature, minimizing energy consumption while achieving high luminous flux. The time parameter (1-12 hours) is also optimized to work synergistically with temperature.
Solution Approach 2:
The patent applies partial action by using controlled excess of certain oxide components (particularly aluminum oxide) in the raw material mixture. This partial excess ensures complete formation of the desired crystal phases and provides a buffer against overheating, allowing the process to stop at lower temperatures than would be required without the excess, thus reducing energy consumption while maintaining high luminous flux.
3Productivity
If the molar ratio of aluminum oxide is increased to improve light extraction efficiency, then the light extraction efficiency increases, but the manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific parameter ranges for molar ratios (e.g., Al: 0.61-0.90, Ga: 0.10-0.39, Sc: 0.001-0.02) that balance light extraction efficiency with manufacturability. These ranges provide flexibility in manufacturing while ensuring optimal crystal phase formation. The parameters are designed to achieve the desired light extraction efficiency without requiring extremely tight tolerances, thus resolving the contradiction between productivity and manufacturing precision.
Solution Approach 2:
The patent employs partial excess of aluminum oxide in the raw material mixture, which provides a buffer against variations in manufacturing precision. This excess ensures that even with normal manufacturing tolerances, the final sintered body achieves the desired light extraction efficiency through complete formation of the aluminum oxide phase and rare earth aluminate crystal phases.
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 produces sintered bodies that emit light with desired colors, achieve high luminous flux, and maintain illumination efficiency by optimizing the molar ratios and specific surface areas of the raw materials, resulting in improved light extraction efficiency.
Implementation Method 1
calcined at specific temperatures to form a sintered body with a rare earth aluminate crystal phase and aluminum oxide phase
Implementation Method 2
a wavelength conversion member containing a fluorescent material that converts a wavelength of light emitted from the LED or LD
Data Source
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AI summary
A method for producing a sintered body includes: providing a raw material mixture containing oxide particles containing Ce, Al, Ga, optionally Sc, and a rare earth element R1 being at least one selected from the group consisting of Y, La, Gd, and Tb to obtain a target composition, wherein a total molar ratio of R1 and Ce is 3, and a molar ratio of Ce, a total molar ratio of Al, Ga, and Sc, a molar ratio of Al and a molar ratio of the Ga are as described in the disclosure; molding the raw material mixture to obtain a molded body; and calcining the molded body to obtain a sintered body containing a rare earth aluminate crystal phase and 2.7% by volume or more to 57.0% by volume or less of an aluminum oxide phase.