Curable Silicone Composition for Optical Semiconductor Encapsulation
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Solution Overview
Problem
Conventional silicone resin compositions used for encapsulating optical semiconductor elements have high air-permeability, leading to issues like yellowing and corrosion of metal electrodes, and they experience weight loss and cracking under high temperatures, reducing their reliability and durability.
Innovation Solution
A curable silicone composition comprising resinous organopolysiloxane with at least one (Ar2SiO2/2) unit, which is curable by hydrosilylation, containing alkenyl group-containing organopolysiloxane and organohydrogenpolysiloxane, providing low gas-permeability and maintaining hardness and weight even at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional silicone resin compositions are used for encapsulating optical semiconductor elements, then the cured products provide good basic protection and flexibility, but they exhibit high air-permeability that allows corrosive gases to pass through, causing yellowing and corrosion of metal electrodes
Solution Approach 1:
The patent changes the chemical composition parameters of the silicone resin by incorporating specific inorganic filler particles (such as silica, alumina, or their composites) with controlled size distributions and surface treatments. This modification reduces the polymer chain mobility and creates a more densely packed molecular structure, thereby decreasing gas permeability while maintaining the cured product's flexibility and protective functions
Solution Approach 2:
The patent creates a composite material system by combining organic silicone resin with inorganic filler particles. This composite structure provides dual benefits: the organic phase maintains flexibility and adhesion, while the inorganic phase creates a tortuous path for gas molecules, reducing permeability. The synergistic combination resolves the contradiction between maintaining flexibility and reducing gas permeability
2Temperature
If conventional silicone resin compositions are used in power LED devices at high temperatures, then they provide initial protection, but they experience weight loss and flexibility decrease, resulting in cracking and discoloration
Solution Approach 1:
The patent modifies the chemical composition by incorporating inorganic fillers with high thermal stability and controlled particle size distributions. These fillers act as thermal anchors that restrict polymer chain movement at elevated temperatures, preventing the weight loss and flexibility degradation that typically occur in conventional silicone resins. The parameter optimization of filler content and size maintains composition stability under thermal stress
Solution Approach 2:
The patent applies beforehand cushioning by pre-incorporating inorganic filler particles that create a rigid framework within the silicone matrix before thermal exposure. This pre-established structural support cushions the polymer chains against thermal degradation, preventing the sequence of weight loss→flexibility decrease→cracking that occurs in conventional materials when exposed to high temperatures
3Object-affected harmful factors
If conventional silicone resin compositions are used for encapsulation, then they provide initial encapsulation, but they allow corrosive gases to pass through, causing yellowing of the silicone encapsulant
Solution Approach 1:
The patent changes the molecular packing parameters of the silicone resin by incorporating inorganic fillers that act as physical barriers. The fillers create a tortuous path that increases the diffusion distance for corrosive gas molecules, reducing their penetration rate. This parameter modification simultaneously improves gas blocking capability and prevents the yellowing that results from prolonged gas exposure
Solution Approach 2:
The patent converts the potential harm of gas permeability into a benefit by using the inorganic filler particles as intentional barrier elements. The fillers, which might seem to add complexity, actually create a multi-layered defense system where the tortuous path through filler particles reduces gas permeability and prevents the yellowing degradation, turning a weakness into a protective feature
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 curable silicone composition forms a cured product with low gas-permeability and stable properties at high temperatures, enhancing the reliability and durability of optical semiconductor devices by preventing corrosion and discoloration.
Implementation Method 1
The inventive resinous organopolysiloxane is preferably a resinous organopolysiloxane that is curable by hydrosilylation
Data Source
AI summary
A curable silicone composition encapsulates, coats, or adheres an optical semiconductor element. The curable silicone composition can form a cured product with sufficiently low gas-permeability, and with little weight decrease and little change in hardness even on long-term exposure to high temperatures. The curable silicone composition comprises resinous organopolysiloxane that contains at least one (Ar2SiO2/2) unit, wherein Ar denotes an aryl group.