Curable Silicone Resin Composition for LED Sulfur Resistance

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Solution Overview

Problem

Conventional LEDs packaging structures are susceptible to sulfur penetration, which reacts with the silver layer to form hydrogen sulfide, reducing light emitting efficiency, and lack superior characteristics such as high hardness, refractive index, flexibility, and heat resistance.

Innovation Solution

A curable silicone resin composition comprising linear polysiloxane, two types of silicone resins, and a Si—H containing polysiloxane, along with a platinum group metal catalyst, is developed to provide sulfur-resistance, high hardness, high refractive index, good flexibility, and heat resistance, while maintaining LED emitting efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional encapsulants are used, then manufacturing cost is low, but sulfur penetrates through the encapsulant and reacts with silver layer to form hydrogen sulfide, decreasing light emitting efficiency

Engineering Contradiction:

Improvelight emitting efficiencyVSAvoidsulfur penetration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a specific silicone resin composition as an intermediary material between the external environment and the LED components. This composition contains sulfur-trapping components that actively intercept and neutralize sulfur before it can reach the silver layer, thereby preventing hydrogen sulfide formation while maintaining encapsulation functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful sulfur penetration issue into a beneficial feature by incorporating sulfur-trapping components into the encapsulant. These components specifically target and bind sulfur, transforming the harmful sulfur that would normally degrade the silver layer into a trapped, neutralized form that actually protects the LED structure.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Illumination intensity

If high hardness and high refractive index are achieved, then optical performance improves, but flexibility and crack resistance may deteriorate

Engineering Contradiction:

Improverefractive indexVSAvoidflexibility and crack resistance

Core Design Contradiction:

Illumination intensityVSStrength

Solution Approach 1:

The patent employs a composite silicone resin system combining multiple resin types (e.g., phenyl-containing silicone resin, methyl-containing silicone resin) with complementary properties. This composite approach allows the encapsulant to simultaneously achieve high refractive index for optimal light extraction and sufficient flexibility for crack resistance, as different resin components contribute different functional properties.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by creating regions with different resin compositions or crosslinking densities within the encapsulant structure. Areas closer to the LED chip may have higher crosslinking for structural stability, while other regions maintain lower crosslinking for flexibility, allowing the material to exhibit both high refractive index and good crack resistance in different locations.

Inventive Principle:

Principle #3Local quality

3Temperature

If high heat resistance is achieved, then thermal stability improves, but manufacturing complexity and cost increase

Engineering Contradiction:

Improveheat resistanceVSAvoidmanufacturing complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The patent replaces complex multi-step manufacturing processes with a simplified one-step curing approach. By designing a silicone resin composition that cures at relatively low temperatures (e.g., 60-100°C) while still achieving high heat resistance, the patent eliminates the need for high-temperature processing equipment and complex manufacturing sequences, thereby reducing manufacturing complexity while maintaining thermal stability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 curable silicone resin composition effectively prevents hydrogen sulfide formation, maintains LED light efficiency, and offers superior mechanical and thermal properties, including high hardness, flexibility, and crack resistance.

Implementation Method 1

a platinum group metal catalyst (D)

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

sulfur in the air would permeate through the encapsulant and then into the LEDs elements so that sulfur would react with the silver layer under the frame so as to produce black hydrogen sulfide (H2S)

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS9371447B2Curable silicone resin composition

Publication Date: 2016.06.21 BENQ MATERIALS CORP

AI summary

The disclosure provides a curable silicone resin composition, including 10 to 50 parts by weight of linear polysiloxane (A); 10 to 40 parts by weight of a first silicone resin (B1); 10 to 40 parts by weight of a second silicone resin (B2); and 15 to 25 parts by weight of a Si—H containing polysiloxane (C) having a general formula given as HR42SiO(SiR32O)nSiR42H, and a platinum group metal catalyst (D). The weight ratio of linear (A)/(the first silicone resin (B1)+the second silicone resin (B2)) is in the range of 0.1 to 2.0. The weight ratio of the first silicone resin (B1)/the second silicone resin (B2) is in the range of 0.2 to 4.0.