Wavelength Conversion Member Sintering Accuracy
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Solution Overview
Problem
Conventional wavelength conversion members for LEDs face challenges in achieving high dimensional and surface accuracy, leading to issues with luminescence intensity and color reproducibility, especially when formed into complex shapes, due to sintering processes that result in deformation and light scattering.
Innovation Solution
A method involving heat treatment of a powder mixture containing glass and inorganic phosphor powders followed by re-press molding with a die to produce wavelength conversion members with improved accuracy and reduced light scattering, using a neutral or reductive atmosphere and controlled temperature below 600°C, and a die with low surface roughness to minimize oxidation and thermal degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a wavelength conversion member is formed by sintering a mixture of glass powder and inorganic phosphor powder, then the member can be produced in various shapes, but the dimensional accuracy and surface accuracy are significantly degraded due to shrinkage and deformation
Solution Approach 1:
The patent applies preliminary action by pre-forming the wavelength conversion member into the desired shape before sintering. The green body is molded with the target geometry, and then sintering is performed to densify it. This preliminary shaping ensures that even after sintering shrinkage occurs, the final dimensions can be controlled more accurately, and surface accuracy is better preserved compared to direct sintering of loose powder.
2Ease of manufacture
If air bubbles remain in the sintered body, then the manufacturing process is simpler, but light scattering loss increases and luminescence intensity is lowered
Solution Approach 1:
The patent utilizes phase transitions during the sintering process to eliminate air bubbles. The heating cycle includes controlled heating rates and holding periods that allow trapped gases to escape as the material undergoes phase changes and densification. This results in a dense, bubble-free sintered body with minimal light scattering, while maintaining relative process simplicity.
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
This method enables the production of wavelength conversion members with high surface accuracy, increased luminescence intensity, and consistent dimensions, reducing the need for grinding and polishing processes, thus enhancing light extraction efficiency and maintaining stable luminescence properties across various shapes.
Implementation Method 1
subjecting a preform made of a powder mixture containing a glass powder and an inorganic phosphor powder to heat treatment, thereby obtaining a sintered powder product
Implementation Method 2
re-press molding the sintered powder product with a die
Data Source
AI summary
To provide a wavelength conversion member having good surface accuracy and dimensional accuracy even when processed in various shapes, and a method for manufacturing the same. A method for manufacturing a wavelength conversion member, including the steps of: subjecting a preform made of a powder mixture containing a glass powder and an inorganic phosphor powder to heat treatment, thereby obtaining a sintered powder product; and re-press molding the sintered powder product with a die.