Glass-Phosphor Composite for LED Color Reproducibility
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Solution Overview
Problem
YAG-based phosphors used in white LEDs result in color imbalance due to weaker red light emission, leading to bluish white light and poor color reproducibility, which affects the reliability of illumination devices.
Innovation Solution
A rare earth ion-containing glass-phosphor composite is manufactured by mixing rare earth ion-containing parent glass with phosphors, where the phosphor is present in 5 wt % to 30 wt % and the glass frit has a glass transition point of 300° C. to 800° C. and a sintering temperature of 200° C. to 600° C., allowing for improved fluorescence and optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If YAG-based phosphors are used in white LEDs, then material stability and high photo-conversion efficiency are improved, but color reproducibility deteriorates due to color imbalance with weaker red light band
Solution Approach 1:
The patent uses a composite material system consisting of YAG-based phosphors embedded in a glass matrix. The glass carrier material combines multiple components (glass frit, rare earth ion compounds, and phosphors) to create a composite that maintains the high stability and efficiency of YAG phosphors while adding color adjustment capabilities through the glass composition, thereby improving color reproducibility without sacrificing material stability
Solution Approach 2:
The patent applies local quality by incorporating rare earth ion compounds specifically into the glass matrix surrounding the YAG phosphors. This localized modification of the glass composition allows for targeted color adjustment in specific regions of the phosphor assembly, enabling fine-tuning of the red light band while preserving the core performance of the YAG phosphors
2Reliability
If YAG-based phosphors are used in white LEDs, then high fluorescence efficiency is improved, but color temperature balance deteriorates resulting in bluish white light
Solution Approach 1:
The patent changes the chemical composition parameters of the glass matrix by incorporating specific rare earth ion compounds (such as red phosphors with emission peaks at 610-680 nm) at controlled concentrations (0.1-5 wt%). This parameter modification adjusts the overall color temperature of the white LED from bluish white to a more balanced white light, while the YAG phosphors continue to provide high fluorescence efficiency
3Ease of manufacture
If phosphor powder is mixed with epoxy or silicone binder, then ease of manufacture is improved, but mechanical stability and thermal stability deteriorate
Solution Approach 1:
The patent replaces expensive and thermally unstable organic binders (epoxy or silicone) with a more stable glass matrix system. The glass carrier, formed by melting and quenching glass frit with phosphors, provides a rigid, thermally stable structure that eliminates the need for organic binders, thereby improving mechanical and thermal stability while maintaining ease of manufacture through a standardized glass processing approach
4Ease of manufacture
If phosphor powder is mixed with epoxy or silicone binder, then ease of manufacture is improved, but photochemical stability deteriorates
Solution Approach 1:
The patent eliminates organic binders (epoxy or silicone) that are susceptible to photochemical degradation under LED operation. Instead, it uses an inorganic glass matrix that is inherently resistant to UV and blue light degradation, providing long-term photochemical stability. The glass-phosphor composite is manufactured by melting and quenching, creating a stable, binder-free structure that maintains its optical properties over time
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 glass-phosphor composite imparts fluorescence to the glass carrier, enhancing mechanical, thermal, and photochemical stability, reducing optical loss, and achieving higher light output efficiency by adjusting color properties and improving color reproducibility.
Implementation Method 1
The glass-phosphor composite imparts fluorescence to the glass carrier, enhancing mechanical, thermal, and photochemical stability, reducing optical loss, and achieving higher light output efficiency
Implementation Method 2
preparing rare earth ion-containing parent glass; mixing the rare earth ion-containing parent glass in a powder state with a phosphor in a powder state
Data Source
AI summary
A method of manufacturing a glass-phosphor composite is disclosed. The method comprises: preparing rare earth ion-containing parent glass; mixing the rare-earth ion-containing parent glass in a power state with a phosphor in a powder state; and providing a glass-phosphor composite using the powder mixture of the rare earth ion-containing parent glass and the phosphor, wherein the mixing includes mixing the rare earth ion-containing parent glass in the powder state with the phosphor in the powder state so that the phosphor in the glass-phosphor composite is in an amount of 5 wt % to 30 wt %, and the preparing includes using a glass frit having a glass transition point of 300° C. to 800° C. and a sintering temperature of 200° C. to 600° C.