Addition/Condensation Curable Silicone Resin Sheet for LED Encapsulation
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Solution Overview
Problem
Existing silicone resin coatings for LEDs face challenges in achieving uniform phosphor dispersion, heat resistance, and UV resistance, particularly due to the degradation caused by hydrosilylation catalysts, which also affect the transparency and stability of the resin layer.
Innovation Solution
An addition/condensation curable silicone resin sheet is developed, combining organopolysiloxanes with alkenyl and hydrosilyl groups, which allows for rapid curing and high heat and light resistance without the need for condensation catalysts, ensuring stable phosphor dispersion and transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrosilylation catalysts are used to enable addition curable silicone resin to cure, then the resin can be cured, but the catalysts accelerate degradation of the resins and reduce heat resistance and UV resistance
Solution Approach 1:
The patent extracts and removes the harmful hydrosilylation catalyst from the system by using a catalyst-free addition cure mechanism, thereby eliminating the degradation effect while maintaining curability through the unique organopolysiloxane structure
Solution Approach 2:
The patent creates a composite curing system combining addition cure and condensation cure mechanisms, where the organopolysiloxane provides addition cure without catalyst and the condensation cure provides crosslinking, achieving both curability and high heat resistance
2Reliability
If condensation catalysts are used to enable condensation cure, then the resin can cure, but the catalysts cause degradation and coloring of the silicone resins
Solution Approach 1:
The patent extracts and removes the harmful condensation catalyst from the system by using moisture-cured condensation mechanism, thereby eliminating the degradation and coloring effects while maintaining curability through ambient moisture
Solution Approach 2:
The patent enables the resin to cure itself using ambient moisture from the environment as the condensation reactant, eliminating the need for external condensation catalysts and their associated harmful effects
3Reliability
If phosphor is dispersed in resin layer, then wavelength conversion is achieved, but non-uniform distribution causes color shift
Solution Approach 1:
The patent achieves homogeneous distribution of phosphor particles in the resin matrix through the unique properties of the organopolysiloxane, which provides uniform viscosity and flow characteristics that prevent phosphor aggregation and ensure even distribution
4Illumination intensity
If addition curable silicone resin is used for LED encapsulation, then light resistance is improved, but heat resistance and UV resistance are insufficient due to catalyst degradation
Solution Approach 1:
The patent creates a composite curing system combining addition cure and condensation cure mechanisms, where the addition cure provides light resistance and the condensation cure provides heat resistance through crosslinking, achieving both properties simultaneously
Solution Approach 2:
The patent removes the harmful catalysts that cause degradation, thereby preserving the inherent light resistance, heat resistance, and UV resistance properties of the silicone resin
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 provides a silicone resin sheet that is easy to handle, maintains high heat and light resistance, and prevents degradation, ensuring a stable and transparent cured layer suitable for LED encapsulation with improved handling and performance.
Implementation Method 1
an addition reaction between alkenyl and hydrosilyl groups
Implementation Method 2
a condensation reaction involving alkoxy or hydroxyl groups
Data Source
AI summary
An addition/condensation curable silicone resin sheet comprising (A) an organopolysiloxane containing at least two silicon-bonded alkenyl groups and at least two silicon-bonded alkoxy or hydroxyl groups, (B) an organopolysiloxane containing at least two silicon-bonded hydrogen atoms and at least two silicon-bonded alkoxy or hydroxyl groups, (C) an organopolysiloxane containing at least two silicon atoms having two alkoxy or hydroxyl groups and one hydrogen atom on a common silicon atom, and (D) a hydrosilylation catalyst is plastic and solid or semisolid at normal temperature. The silicone resin sheet is easy to work, effective to cure, and likely to form a cured layer around an LED chip.