Curable Organo Polysiloxane Encapsulant for Light Emitting Devices
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Solution Overview
Problem
Conventional siloxane encapsulants for light emitting devices face challenges in maintaining mechanical properties and thermal resistance while preventing moisture and gas permeability, often resulting in increased viscosity and coefficient of thermal expansion, which can lead to cracking and reduced optical performance.
Innovation Solution
A curable organo polysiloxane composition comprising specific silicon-bonded compounds with a number average molecular weight less than 4,000, including a first siloxane compound with silicon-bonded hydrogen and a second siloxane compound with silicon-bonded alkenyl groups, forming a dense structure with improved hardness and low modulus at high temperatures, and a hydrosilylation reaction to enhance bonding and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional siloxane encapsulants are used to prevent moisture and gas permeability, then protection performance is improved, but viscosity increases and coefficient of thermal expansion increases leading to cracking
Solution Approach 1:
The patent changes the molecular weight parameter of the siloxane compound to less than 4,000, which fundamentally alters the physical properties of the encapsulant. This parameter change reduces both viscosity and coefficient of thermal expansion while maintaining protection performance, thereby preventing cracking without sacrificing reliability
Solution Approach 2:
The patent creates a composite curable composition by combining low molecular weight siloxane compounds with specific functional groups (silicon-bonded hydrogen and silicon-bonded alkenyl groups). This composite approach allows the material to achieve both low thermal expansion coefficient and adequate mechanical strength, resolving the contradiction between protection performance and cracking prevention
2Strength
If conventional siloxane encapsulants are used to maintain mechanical properties, then strength is improved, but thermal resistance decreases and moisture permeability increases
Solution Approach 1:
The patent applies parameter changes by controlling the molecular weight to less than 4,000 and specifying functional group compositions. This results in a material that simultaneously achieves improved mechanical strength and enhanced thermal resistance, while also reducing moisture permeability through the dense molecular structure created by the low molecular weight siloxane compounds
3Reliability
If conventional siloxane encapsulants are used to prevent moisture permeability, then protection is improved, but optical performance deteriorates
Solution Approach 1:
The patent changes the molecular weight parameter to less than 4,000, which creates a denser molecular structure that reduces moisture permeability while simultaneously improving optical performance. The low molecular weight siloxane compounds provide better light transmission and reduced yellowing, thus maintaining optical performance while enhancing protection
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 composition provides enhanced mechanical properties, thermal impact resistance, and reduced moisture and gas transmittance, maintaining optical performance and preventing deterioration of light emitting devices, with improved adherence and chemical resistance.
Implementation Method 1
at least one first siloxane compound including a silicon-bonded hydrogen; and at least one second siloxane compound including a silicon-bonded alkenyl group
Data Source
AI summary
A curable organo polysiloxane composition, an encapsulant, and an electronic device, the composition including at least one compound represented by the following Chemical Formula 1 and having a number average molecular weight of less than about 4,000, at least one first siloxane compound including a silicon-bonded hydrogen; and at least one second siloxane compound including a silicon-bonded alkenyl group: