Curable Silicone Composition for LED Encapsulation
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Solution Overview
Problem
Current materials for coating and encapsulating optical devices, such as LEDs, have not been optimized for key properties like quick curing speed, high transparency, high hardness, and good adhesion simultaneously.
Innovation Solution
A curable organopolysiloxane composition comprising a combination of linear organopolysiloxanes, cyclic organopolysiloxanes, SiH crosslinkers, and polyaddition catalysts, along with an adhesion promoter, which allows for fast curing and strong adhesion to substrate surfaces without the need for fillers, maintaining high transparency and hardness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional materials are used for coating and encapsulating optical devices, then basic protection is provided, but quick curing speed, high transparency, high hardness, and good adhesion are not simultaneously achieved
Solution Approach 1:
The patent changes the chemical parameters of the silicone composition by incorporating specific ratios of cyclic organopolysiloxane (5-20 wt%), linear organopolysiloxane (80-75 wt%), and SiH crosslinker (5-15 wt%). These parameter changes enable the composition to simultaneously achieve fast curing speed, high transparency, high hardness, and good adhesion, resolving the contradiction between basic protection and optimization for multiple key properties.
Solution Approach 2:
The patent creates a composite material system combining multiple organopolysiloxane types and crosslinkers. The composite composition includes cyclic organopolysiloxane for fast curing, linear organopolysiloxane for transparency and flexibility, and SiH crosslinker for hardness enhancement. This composite approach allows simultaneous achievement of multiple desirable properties that single materials cannot provide.
2Strength
If fillers are added to improve hardness, then hardness increases, but transparency decreases
Solution Approach 1:
The patent replaces the mechanical approach of adding fillers to increase hardness with a chemical approach using SiH crosslinkers. The crosslinking reaction creates a three-dimensional network structure that enhances hardness at the molecular level without introducing particulate fillers that would scatter light and reduce transparency. This substitution resolves the contradiction between hardness enhancement and transparency maintenance.
3Strength
If adhesion promoters are added to improve adhesion, then adhesion increases, but curing speed and transparency may be compromised
Solution Approach 1:
The patent uses cyclic organopolysiloxane that serves multiple functions simultaneously: it provides fast curing through its cyclic structure reactivity, maintains high transparency due to its chemical composition, enhances hardness via crosslinking, and improves adhesion to substrate surfaces. This multi-functional component resolves the contradiction by achieving adhesion enhancement without compromising curing speed or transparency.
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 transparency (>82% at 450 nm), hardness (>75 shore A), and fast curing speed (within 1-120 minutes at 80-200°C), with excellent adhesion to glass and aluminum, suitable for various optical applications including LED encapsulation.
Implementation Method 1
an effective amount of one or more polyaddition catalysts
Implementation Method 2
a SiH crosslinker
Data Source
AI summary
Curable organopolysiloxane compositions and their cured products with superior properties are described as well as their uses as materials for optical devices, such as LEDs.