Curable Silicone Composition for Optical Semiconductor Sealing
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Solution Overview
Problem
Conventional curable silicone compositions have insufficient thixotropic properties, leading to flow issues and the inability to achieve desired shapes when applied to optical semiconductor devices.
Innovation Solution
A curable silicone composition comprising at least one resinous organopolysiloxane with alkenyl and aryl groups, organohydrogen polysiloxane, an inorganic filler with a high reflective index, and a combination of polyether-modified organopolysiloxanes with terminal —OH and alkoxy or acyloxy groups, along with a hydrosilylation catalyst.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional curable silicone compositions are used, then the composition can be applied to optical semiconductor devices, but the composition has insufficient thixotropic properties causing flow issues and inability to achieve desired shapes
Solution Approach 1:
The patent uses a composite material system comprising multiple polysiloxane components with different functions: a resinous organopolysiloxane component (A) providing thixotropic properties and shape retention, an organohydrogen polysiloxane component (B) for crosslinking, and polyether-modified organopolysiloxane components (D1) and (D2) for adhesion and flow control. This multi-component composite approach resolves the contradiction by combining materials with complementary rheological properties to achieve both thixotropy and ease of application.
Solution Approach 2:
The patent modifies the rheological parameters of the silicone composition by incorporating specific components with controlled molecular weights and functional groups. Component (A) has a viscosity of 100-10,000 mPa·s at 25°C to provide thixotropic behavior, while components (D1) and (D2) with polyether chains modify the flow characteristics. This parameter optimization enables the composition to exhibit shear-thinning behavior for easy application while maintaining shape retention.
2Shape
If the composition is made to have high thixotropic properties, then shape retention is improved, but transparency and reflective index may be compromised
Solution Approach 1:
The patent applies local quality by assigning different functional roles to different components of the composition. Component (A) with higher molecular weight and resinous structure provides thixotropic properties and shape retention in specific regions of the composition, while components (B), (D1), and (D2) with lower molecular weights and different functional groups ensure overall transparency and optical clarity. This functional differentiation allows simultaneous achievement of shape retention and transparency.
Solution Approach 2:
The composite material system combines components with different optical and rheological properties. The resinous organopolysiloxane (A) contributes to shape retention while the organohydrogen polysiloxane (B) and polyether-modified components (D1, D2) maintain optical clarity. The synergistic interaction of these composite components resolves the contradiction between shape retention and transparency.
3Illumination intensity
If inorganic filler with high reflective index is added, then light extraction is improved, but wettability on organic substrates may deteriorate
Solution Approach 1:
The patent uses polyether-modified organopolysiloxane components (D1) and (D2) as intermediary substances that bridge the inorganic filler and organic substrate. These components contain polyether chains that can interact with both inorganic surfaces and organic substrates, improving wettability and adhesion. The intermediary action of these modified polysiloxanes resolves the contradiction between high reflective index filler incorporation and maintained wettability on organic substrates.
Solution Approach 2:
The patent modifies the surface chemistry parameters of the composition by incorporating polyether-modified components that change the interfacial properties. The polyether chains in components (D1) and (D2) alter the surface energy and wettability characteristics, enabling good adhesion to organic substrates even in the presence of inorganic fillers with high reflective indices. This parameter modification resolves the wettability-deterioration issue.
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 achieves high thixotropic properties, resulting in cured products with high transparency and reflective index, suitable for optical semiconductor devices, and ensures reliable wettability on organic substrates.
Implementation Method 1
polyether-modified organopolysiloxane having at least one terminal —OH group in a polyether chain
Implementation Method 2
polyether-modified organopolysiloxane having at least one terminal alkoxy or acyloxy group in a polyether chain
Implementation Method 3
inorganic filler having a reflective index of 1.50 or higher
Implementation Method 4
inorganic filler having a reflective index of 1.50 or higher
Implementation Method 5
hydrosilylation catalyst
Implementation Method 6
hydrosilylation catalyst
Data Source
AI summary
The present disclosure provides a curable silicone composition comprising: (A) at least one resinous organopolysiloxane having at least two alkenyl groups and at least one aryl group per molecule; (B) at least one organohydrogen polysiloxane having at least two silicon-bonded hydrogen atoms per molecule; (C) at least one inorganic filler having a reflective index of 1.50 or higher; (D) two or more polyether-modified organopolysiloxane comprising a combination of (d-1) at least one polyether-modified organopolysiloxane having at least one terminal —OH group in a polyether chain, and (d-2) at least one polyether-modified organopolysiloxane having at least one terminal alkoxy or acyloxy group in a polyether chain; and (E) at least one hydrosilylation catalyst. A sealing material formed from the curable silicone composition, and an optical semiconductor device comprising the sealing material are also disclosed.