Curable Composition for LED Encapsulation
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Solution Overview
Problem
Current LED encapsulants face issues with light linearity, heat resistance, and discoloration due to the use of inorganic and polymer particles, and epoxy resins have low light transmittance and mechanical durability.
Innovation Solution
A curable composition comprising polyorganosiloxanes with specific empirical formulas and a silicon-hydride functional compound, capable of curing through hydrosilylation, is developed to address these issues, providing excellent processability, workability, and light dispersity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If inorganic particles are blended to an encapsulant to disperse light, then light scattering is improved, but viscosity of resin increases and particles may precipitate
Solution Approach 1:
The patent uses polymer particles as an intermediary medium to achieve light scattering without the drawbacks of inorganic particles. These polymer particles are specifically designed with refractive indices matching the resin matrix, allowing them to scatter light effectively while maintaining resin processability and preventing precipitation due to density differences.
Solution Approach 2:
The patent changes the refractive index parameter of the dispersing particles to match that of the resin matrix. By carefully selecting polymer particles with specific refractive indices (within ±0.05 of the resin's refractive index), the patent achieves effective light scattering while avoiding the viscosity increase and precipitation problems associated with inorganic particles.
2Illumination intensity
If polymer particles are used to scatter light, then light scattering is improved, but heat resistance and light resistance are insufficient causing discoloration
Solution Approach 1:
The patent employs composite material design by selecting polymer particles with specific chemical compositions that combine light-scattering capability with high heat and light resistance. The composite encapsulant consists of the resin matrix and dispersed polymer particles, where the polymer component provides both optical scattering function and thermal/optical stability.
3Strength
If epoxy resin is used as encapsulant, then adhesive strength and mechanical durability are improved, but light transmittance in blue/UV region decreases and light resistance is low
Solution Approach 1:
The patent changes the chemical composition parameters of the resin matrix to achieve high light transmittance in the blue and UV regions while maintaining mechanical durability. Specifically, the patent uses silicone resin or acrylic resin as the base matrix, which have superior optical properties compared to epoxy resin, while incorporating adhesion promoters to maintain strong bonding.
4Use of energy by moving object
If high-linear light is directly observed, then light emission efficiency is maintained, but eye fatigue and damage occur
Solution Approach 1:
The patent applies local quality modification by incorporating light-scattering polymer particles throughout the encapsulant matrix. This creates localized scattering centers that redirect high-linear light in multiple directions, reducing the linear intensity while maintaining overall light output. The scattering effect is distributed uniformly throughout the encapsulant volume.
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 effectively scatters and disperses light, maintains mechanical strength, and exhibits excellent heat resistance and light resistance, preventing discoloration over time, making it suitable for LED encapsulation.
Implementation Method 1
a curable composition including components which can be cured by hydrosilylation, for example, a reaction between an aliphatic unsaturated bond and a hydrogen atom
Data Source
AI summary
Provided are a curable composition and its use. The curable composition having excellent processability, workability, heat resistance, and light resistance, and having no problem of discoloring despite using for a long time may be provided. The curable composition which may scatter light and disperse linearity of light when used as an encapsulant of an optical semiconductor such as an LED may be provided.