White Light Glass-Ceramic LED Luminescent Material
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Solution Overview
Problem
Current white light LED devices using blue-light LED chips with fluorescent powders face issues such as epoxy resin deterioration, complex processes, high costs, and unstable color coordinates due to differing light decay rates, while glass ceramics with rare earth ions have low solid solubility and high phonon energy, reducing luminescent intensity.
Innovation Solution
A white light emitting glass ceramic with the chemical formula aSiO2·bAl2O3·cNaF·dCeF3·nDyF3·mAg is produced by calcinating and reductively annealing a mixture of SiO2, Al2O3, NaF, CeF3, DyF3, and AgNO3 in a stoichiometric ratio, introducing elemental Ag particles to enhance luminescent intensity through surface plasma resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blue-light LED chips with fluorescent powders are used for white light LED devices, then the luminescent efficiency is relatively high and the preparation method is well-established, but the epoxy resins deteriorate and turn yellow under blue, violet or ultra-violet light illumination, reducing device service life
Solution Approach 1:
The invention extracts and removes the epoxy resin encapsulation layer from the LED device structure, replacing it with a glass ceramic luminescent material that can be directly bonded to the LED chip. This eliminates the yellowing and deterioration problem of epoxy resins under blue, violet or ultra-violet light illumination while maintaining device protection and light transmission functions.
Solution Approach 2:
The invention uses glass ceramic as a composite luminescent material that combines the functions of encapsulation and light emission. The glass ceramic material integrates structural support, protection, and luminescence properties in a single component, replacing the separate epoxy resin encapsulation layer and fluorescent powder combination.
2Ease of manufacture
If blue-light LED chips with fluorescent powders are used, then the luminescent efficiency is relatively high, but the process becomes complex and the cost increases
Solution Approach 1:
The invention merges the luminescent function and encapsulation function into a single glass ceramic component. Instead of separately applying fluorescent powders and then encapsulating with epoxy resin, the glass ceramic is directly bonded to the LED chip, integrating multiple functions into one material and simplifying the manufacturing process.
Solution Approach 2:
The glass ceramic material serves multiple functions simultaneously: it acts as a substrate, provides structural support, protects the LED chip, and generates luminescence. This multi-functionality reduces the number of separate components and manufacturing steps required.
3Stability of the object's composition
If blue-light LED chips with fluorescent powders are used, then the luminescent efficiency is relatively high, but the light decay rates of the fluorescent powders and chips differ, causing unstable color coordinates and light drift
Solution Approach 1:
The invention changes the material parameter from organic fluorescent powders to inorganic glass ceramic with rare earth ions. This material substitution ensures that the luminescent material and LED chip have compatible thermal and optical properties, resulting in matched light decay rates and stable color coordinates over the device lifetime.
4Illumination intensity
If rare earth ions are doped in glass ceramic substrate, then the luminescent efficiency can be improved, but the solid solubility of rare earth ions in glass lattice is relatively low and the phonon energy is high, reducing luminescent intensity
Solution Approach 1:
The invention changes the chemical composition parameters of the glass ceramic, specifically using a fluoride-containing glass system with modified network structure. This composition adjustment increases the solid solubility of rare earth ions and reduces phonon energy, thereby enhancing luminescent intensity while maintaining material stability.
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 ceramic achieves high luminescent efficiency and stability, suitable for LED applications, with increased luminescent intensity and potential for broad application in lighting fields, overcoming the limitations of existing technologies.
Implementation Method 1
by introducing elemental Ag particles, the resulted surface plasma resonance effect significantly increases the luminescent intensity of the rare earth ions doped in the glass ceramic substrate
Implementation Method 2
glass ceramics, which achieve luminescence under excitation of violet or ultraviolet lights
Implementation Method 3
glass ceramics capable of achieving high performance luminescence are very suitable as the luminescent media materials in the LED lamination field
Implementation Method 4
reductively annealing the glass precursor in a reductive atmosphere, and cooling to produce the white light emitting glass ceramic having the chemical formula of aSiO 2 ·bAl 2 O 3 ·cNaF·dCeF 3 ·nDyF 3 ·mAg
Data Source
Figure 1~2
AI summary
A white light emitting glass-ceramic. The chemical formula of the glass-ceramic is aSiO2·bAl2O3·cNaF·dCeF3·nDyF3·mAg, wherein a, b, c, d, n and m are, by mol part, 25~50, 15~30, 10~30, 10~25, 0.01~1 and 0.01~1, respectively, and a+b+c+d=100. A method for producing said glass-ceramic is also provided. Silver ion is doped in the glass-ceramic in the form of silver particles by means of sintering and reduction annealing treatment, and thus the luminescence properties of rare earth ion is improved.