Rare Earth Ion Doped Silicate Glass for LED Lighting
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Solution Overview
Problem
Current white light LED lighting devices using blue light LED chips and fluorescent powders face issues such as short device lifetime due to aging epoxy resin, complex and costly encapsulation processes, unstable color coordinates, and drifting white light.
Innovation Solution
Development of rare earth ion doped silicate luminescence glass with a specific formula (aM2O.bM′2O3.cSiO2.dRE2O3) and a simplified preparation method involving calcining and annealing of raw materials to produce a stable, high-transmittance glass that can replace epoxy resin, offering improved chemical and thermal stability, and low production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If epoxy resin is used to encapsulate luminescence fluorescent powder, then the device can be manufactured, but the device lifetime is reduced due to aging of the epoxy resin
Solution Approach 1:
The invention extracts and removes the epoxy resin encapsulation layer from the LED device structure, replacing it with a glass ceramic luminescence material that directly contacts the blue light LED chip. This eliminates the aging problem of epoxy resin and extends device lifetime.
Solution Approach 2:
The invention uses glass ceramic composite material doped with rare earth ions (such as Y3Al5O12:Ce3+) as the luminescence material. This composite material combines the advantages of glass (good chemical stability, low cost) and ceramic (high temperature resistance, mechanical strength), providing both durability and luminescence performance.
2Illumination intensity
If fluorescent powder is used with blue light LED chips, then white light can be produced, but the process becomes complex and cost increases
Solution Approach 1:
The invention merges the luminescence function and the structural support function into a single glass ceramic luminescence material. This material directly contacts the LED chip and provides both mechanical support and light conversion, eliminating the need for separate encapsulation processes and reducing manufacturing complexity.
Solution Approach 2:
The glass ceramic luminescence material serves multiple functions simultaneously: it acts as the luminescence conversion layer, provides structural support, offers chemical stability, and enables direct contact with the LED chip. This multi-functionality simplifies the overall device structure and manufacturing process.
3Illumination intensity
If fluorescent powder is used to convert blue light to yellow or green-orange light, then white light is produced, but the color coordinate becomes unstable and white light drifts
Solution Approach 1:
The invention changes the chemical composition parameters of the luminescence material by using glass ceramic with specific rare earth ion doping (e.g., Y3Al5O12:Ce3+). This compositional change results in stable luminescence properties and consistent color coordinates, eliminating the drift problem associated with conventional fluorescent powders.
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 rare earth ion doped silicate luminescence glass exhibits good stability, homogeneity, and luminescent properties, enabling high-performance luminescence suitable for LED lighting with improved durability, cost-effectiveness, and versatility in shape and size, addressing the limitations of existing technologies.
Implementation Method 1
fluorescent powders which are capable of emitting yellow or green-orange light when excited by blue light
Implementation Method 2
annealing the raw material for 0.5 ̃24 h after raising temperature to 600 ̃1100° C.
Data Source
AI summary
A rare earth ion doped silicate luminescence glass and preparation method thereof are provided. The luminescence glass is the material with the following formula: aM2O.bM′2O3.cSiO2.dRE2O3, wherein M is at least one of Na, K and Li, M′ is at least one of Y, Gd, La, Sc and Lu, RE is at least one of Ce, Tm, Tb, Ho, Dy, Er, Nd, Sm, Eu and Pr. The preparation method is: grinding the raw material until mixed uniformly, calcining the raw material at 1200-1500° C. for 1-5 h, cooling to room temperature, annealing at 600-1100° C. for 0.5-24 h, cooling to room temperature again, molding then getting the product. The performance of the product is stable. The product is homogenous, and the luminescence performance is good. The light transmittance is high. The process of the preparation method is simple and with low cost.