Phosphor-in-Glass Wavelength Converter Darkening Prevention
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Solution Overview
Problem
The phosphor-in-glass (PiG) wavelength converters experience darkening during spark plasma sintering due to graphite contamination and reduced atmospheres, leading to reduced efficacy and potential damage to nitride-based phosphors.
Innovation Solution
A method involving mixing phosphor materials with glass components and an oxidizing agent, followed by applying pressure and current to reduce darkening by oxidizing CO into CO2, thereby minimizing carbon contamination and maintaining phosphor integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If spark plasma sintering is used to produce PiG, then processing temperature is reduced and porosity is decreased, but darkening occurs due to graphite contamination and CO diffusion
Solution Approach 1:
An oxidizing atmosphere is introduced as an intermediary medium during SPS processing. This oxidizing environment reacts with carbon contaminants and CO gas to convert them into CO2, preventing carbon deposition and darkening in the glass matrix while maintaining the low-temperature advantage of SPS
Solution Approach 2:
The atmospheric composition parameter is changed from reducing or neutral to oxidizing during the SPS process. This parameter change transforms the chemical environment to prevent carbon contamination and CO diffusion into the glass, thereby eliminating darkening while preserving the low-temperature processing benefit
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 significantly reduces darkening and enhances the quantum efficiency of PiG samples to at least 95%, improving their performance and stability.
Implementation Method 1
adding at least one oxidizing agent to the first mixture... mixing the oxidizing agent with the first mixture... oxidizing CO into CO2
Implementation Method 2
applying pressure and current to the second mixture... spark plasma sintering (SPS)... additional pressure applied
Implementation Method 3
One way to make PiG samples is using spark plasma sintering (SPS)
Implementation Method 4
It can absorb all or partial of excitation light, such as blue or near UV light, from a LED chip and convert it to the light with another wavelength
Data Source
AI summary
A method for preparing a glass composite wavelength converter comprising the steps of providing at least one phosphor material, providing a powder of glass components, mixing the phosphor material and the powder of glass components, thereby preparing a first mixture, adding at least one oxidizing agent to the first mixture, mixing the oxidizing agent with the first mixture, thereby preparing a second mixture, applying pressure and current to the second mixture, thereby preparing a glass composite wavelength converter is described. Furthermore, a glass component wavelength converter and a light source are described.