Light-Shielding Resin for LED Packages
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Solution Overview
Problem
Existing curable compositions for light-emitting diodes (LEDs) face challenges in providing effective light-shielding while maintaining adhesive properties and preventing resin degradation, with issues of high flow leveling leading to inadequate thickness and interference with electrical access, and a lack of methods for coating LED package aperture sidewalls effectively.
Innovation Solution
A curable composition comprising a thermoplastic or thermosetting resin combined with an inorganic member, a silicon compound, a hydrosilylation catalyst, and a silane coupling agent, which forms a light-shielding paste that can be applied to LED package sidewalls, reducing flow-out and ensuring adequate light-shielding without compromising electrical access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a curable composition with high flow leveling property is used, then the composition spreads easily and forms a uniform coating, but the coating thickness becomes insufficient and electrical access is interfered with
Solution Approach 1:
The patent modifies the chemical composition parameters of the curable composition by incorporating specific ratios of addition reaction-curable silicone (5-50 mass%), condensation reaction-curable silicone (5-50 mass%), and inorganic powder (50-95 mass%). This parameter adjustment reduces the flow leveling property to maintain adequate coating thickness while preserving sufficient coating uniformity for effective light-shielding.
Solution Approach 2:
The invention creates a composite curable composition combining multiple silicone types (addition reaction-curable and condensation reaction-curable) with inorganic powders. This composite structure balances the flow characteristics and curing properties, enabling the coating to maintain both spreadability and sufficient thickness without compromising electrical access.
2Device complexity
If the package resin is exposed to light without light-shielding, then the LED structure remains simple, but the package resin deteriorates causing decreased adhesion and reflectivity
Solution Approach 1:
The patent applies a light-shielding resin coating to the package aperture sidewalls before the LED operates. This preliminary protective action prevents light-induced deterioration of the package resin, maintaining adhesion strength and reflectivity over time while keeping the overall package structure relatively simple.
Solution Approach 2:
The light-shielding resin acts as an intermediary protective layer between the light source and the package resin. This intermediate coating blocks harmful light from reaching the package resin, preventing deterioration and maintaining reliability without significantly complicating the package structure.
3Strength
If existing addition reaction-curable silicone compositions are used, then adhesive properties are improved, but light-shielding ability is insufficient
Solution Approach 1:
The patent combines addition reaction-curable silicone (providing adhesive strength) with condensation reaction-curable silicone and high-content inorganic powders (50-95 mass%). This composite formulation achieves both strong adhesion to the package resin and effective light-shielding capability, resolving the contradiction between adhesive properties and light-blocking performance.
Solution Approach 2:
The invention applies different functional components to different aspects of the coating material: addition reaction-curable silicone provides local adhesive quality at the interface with the package resin, while the high concentration of inorganic powders provides local light-shielding quality in the bulk coating, achieving both requirements simultaneously.
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 light-shielding resin layer on LED package sidewalls with improved adhesive properties and reduced flow-out, effectively protecting the LED from light-induced resin degradation and maintaining performance characteristics.
Implementation Method 1
a curable composition comprising (A) an organic compound comprising an organic main chain containing at least two carbon-carbon double bonds reactive with a SiH group in each molecule, (B) a silicon compound having at least two SiH groups in each molecule, (C) a hydrosilylation catalyst
Implementation Method 2
a curable composition comprising (A) an organic compound comprising an organic main chain containing at least two carbon-carbon double bonds reactive with a SiH group in each molecule, (B) a silicon compound having at least two SiH groups in each molecule, (C) a hydrosilylation catalyst, (D) a silane coupling agent and/or an epoxy group-containing compound
Implementation Method 3
a curable composition comprising (A) an organic compound comprising an organic main chain containing at least two carbon-carbon double bonds reactive with a SiH group in each molecule, (B) a silicon compound having at least two SiH groups in each molecule, (C) a hydrosilylation catalyst, (D) a silane coupling agent and/or an epoxy group-containing compound, (E) a silanol condensation catalyst, and (F) an inorganic member
Data Source
AI summary
A light-shielding paste which contains a thermoplastic resin and an inorganic member as essential components or which contains a thermosetting resin and an inorganic member as essential components is provided. A curable composition and light-shielding paste comprising the composition are provided which contains, as essential components, (A) an organic compound comprising an organic main chain containing at least two carbon-carbon double bonds reactive with a SiH group in each molecule, (B) a silicon compound having at least two SiH groups in each molecule, (C) a hydrosilylation catalyst, (D) a silane coupling agent and/or an epoxy group-containing compound, (E) a silanol condensation catalyst, and (F) an inorganic member. The curable composition can further contain (G) silica. Also provided is a method of forming a light-shielding resin layer on a LED package having an aperture comprising a bottom and sidewalls. The curable composition is excellent in light-shielding ability.