Epoxy-Silicone Mixed Resin for LED Encapsulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional resin compositions for encapsulating light-emitting semiconductor devices face issues with moisture resistance, light resistance, adhesiveness, and luminous efficiency due to high water absorption, low transmittance, tacky surfaces, and poor adhesion, especially when subjected to thermal shocks.
Innovation Solution
An epoxy-silicone mixed resin composition incorporating an organosilicon compound, epoxy resin, and an aluminum-based curing catalyst, along with a silicone elastomer, undergoes a hydrosilylating reaction and epoxy resin curing to produce a transparent, tack-free, and highly adhesive cured product with improved crack resistance and refractive index matching, enhancing luminous efficiency and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a high-hardness silicone resin is used to improve crack resistance, then crack resistance is improved, but adhesiveness deteriorates causing peeling under thermal shocks
Solution Approach 1:
The patent uses a composite resin system combining epoxy resin and silicone resin in specific proportions (epoxy resin 70-95 wt%, silicone resin 5-30 wt%). This composite approach allows the epoxy component to provide strong adhesion to ceramic and plastic casings while the silicone component contributes crack resistance and flexibility, resolving the contradiction between adhesion and crack resistance that plagues single-component systems.
Solution Approach 2:
The patent carefully controls the molecular weight, viscosity, and functional group content of both epoxy and silicone resins to optimize performance. By adjusting parameters such as the epoxy equivalent weight (150-400 g/eq) and silicone resin content (5-30 wt%), the formulation achieves both strong adhesion and crack resistance without peeling under thermal shock conditions.
2Illumination intensity
If conventional transparent epoxy resin is used, then transparency is achieved, but light resistance deteriorates due to low transmittance for short wavelength light and discoloration
Solution Approach 1:
The patent combines transparent epoxy resin with specially formulated silicone resin that has superior UV resistance and does not yellow. This composite system maintains the transparency needed for light extraction while the silicone component protects against UV degradation and discoloration, significantly improving light resistance compared to conventional epoxy alone.
Solution Approach 2:
The patent introduces hydrogenated bisphenol A epoxy resin with specific structural modifications in certain regions of the molecular structure to enhance UV stability. The hydrogenation of aromatic rings reduces susceptibility to UV-induced yellowing while maintaining transparency in the visible range, addressing light resistance issues locally within the resin structure.
3Strength
If silicone resin is used to improve crack resistance, then crack resistance is improved, but surface tackiness increases attracting dust and impairing light transmittance
Solution Approach 1:
The patent carefully controls the crosslinking density and molecular weight of the silicone resin to achieve optimal surface properties. By adjusting the silicone resin content (5-30 wt%) and using appropriately sized molecules, the formulation achieves sufficient crack resistance while maintaining a non-tacky surface that does not attract dust and preserves light transmittance.
Solution Approach 2:
The patent uses different types of silicone resin with distinct molecular structures and crosslinking characteristics to achieve localized properties: the silicone resin provides crack resistance in the bulk material while the surface remains non-tacky. This is achieved through controlled crosslinking and selection of silicone resin with appropriate chain length and functional groups.
4Ease of manufacture
If low refractive index resin is used, then ease of manufacture is improved, but luminous efficiency deteriorates due to reflection at the interface with semiconductor crystal
Solution Approach 1:
The patent optimizes the refractive index of the encapsulating resin by selecting epoxy and silicone resins with specific refractive indices (typically 1.45-1.60) that closely match the semiconductor crystal. This parameter optimization reduces reflection at the interface, improving light extraction efficiency without complicating the manufacturing process.
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 epoxy-silicone mixed resin composition provides light-emitting semiconductor devices with excellent adhesiveness, crack resistance, and luminous efficiency, preventing peeling and maintaining transparency under thermal shocks, thus ensuring reliable and efficient light emission.
Implementation Method 1
an aluminum-based curing catalyst, undergoes a hydrosilylating reaction and epoxy resin curing
Implementation Method 2
an organosilicon compound, epoxy resin, and an aluminum-based curing catalyst, along with a silicone elastomer, undergoes a hydrosilylating reaction and epoxy resin curing
Data Source
AI summary
An epoxy-silicone mixed resin composition to give a transparent cured product which comprises [I] 100 parts by weight of a curable resin composition containing an organosilicon compound and an epoxy resin as essential components, and [II] 0.1 to 50 parts by weight of a silicone elastomer having a refractive index within 10% of that of a cured product of the curable resin composition. It is suitable for use as an encapsulator for light-emitting semiconductors.