LED Encapsulation Material with High Refractive Index and Moisture Barrier
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Solution Overview
Problem
Current LED encapsulation materials face challenges in achieving high refractive index, temperature stability, and water vapor barrier properties while maintaining efficient production and light output, especially after aging.
Innovation Solution
A formulation comprising a polymer with specific repeating units and surface-modified nanoparticles without zirconium dioxide, which provides a high refractive index with low temperature dependence and enhanced barrier properties, allowing for efficient curing and improved LED performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If silicone-based encapsulation materials are used, then heat resistance and optical clarity are improved, but gas permeability and moisture permeability increase leading to degradation
Solution Approach 1:
The patent uses a composite material system combining organopolysiloxane polymer with inorganic fillers (such as aluminum oxide, aluminum nitride, or boron nitride particles) to create an encapsulation material that maintains the heat resistance of silicones while adding moisture barrier properties through the inorganic components. This composite approach allows simultaneous achievement of thermal stability and improved barrier performance.
2Illumination intensity
If phenyl silicones with high refractive index are used, then light output is improved, but thermal and optical stability deteriorates due to aromatic groups
Solution Approach 1:
The patent changes the chemical composition parameters by using polymers with specific repeating units that provide high refractive index without aromatic groups. The formulation includes polymers containing silicon-oxygen-silicon bonds with specific side groups that achieve refractive index above 1.50 while maintaining thermal stability above 150°C and optical stability against yellowing.
Solution Approach 2:
The patent replaces the unstable aromatic group-containing phenyl silicones with alternative polymer structures that provide similar or better performance without the degradation issues. This substitution uses polymers with silicon-oxygen backbones and specific side chains that offer comparable refractive index but superior long-term stability.
3Strength
If epoxides are used, then adhesion and chemical resistance are improved, but moisture resistance and light resistance deteriorate
Solution Approach 1:
The patent extracts and eliminates the problematic epoxy functional groups from the encapsulation material formulation. Instead, it uses organopolysiloxane polymers with specific repeating units that provide adequate adhesion through silicon-oxygen bonding while inherently offering superior moisture resistance and UV stability, thus removing the harmful moisture absorption and yellowing characteristics of epoxides.
4Reliability
If glass is used, then optical properties and durability are improved, but compatibility with standard LED manufacturing processes deteriorates
Solution Approach 1:
The patent changes the material state from solid glass to a polymer-based encapsulation material that can be processed in liquid or paste form and then cured. This allows the material to be applied using standard LED manufacturing techniques such as dispensing, molding, or coating, followed by thermal or UV curing to achieve the final encapsulated structure, thereby matching glass-level durability with polymer-level processability.
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 solution results in LEDs with increased light output, improved color point stability, and enhanced water vapor barrier properties, addressing the limitations of existing materials by providing a high refractive index and temperature stability.
Implementation Method 1
The encapsulation material according to the present invention provides a high refractive index which shows a low temperature dependence and thereby allows the preparation of high-performance LEDs having an increased light output
Implementation Method 2
curing said formulation at a temperature of 70 to 300°C for a period of 1 to 24 h
Implementation Method 3
The encapsulation material shows improved barrier properties towards water vapor
Data Source
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AI summary
The present invention relates to a formulation suitable for the preparation of a highly refractive encapsulation material with good barrier properties towards water vapor for an LED, to an encapsulation material for an LED having a high refractive index and good barrier properties towards water vapor which is obtainable from said formulation and to a light emitting device (LED) comprising said encapsulation material. The formulation comprises a polymer comprising a first repeating unit U1 and a second repeating unit U2; and a surface-modified nanoparticle, wherein the surface-modified nanoparticle does not contain any zirconium dioxide.