Thermal Interface Adhesive for LED Packaging
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Solution Overview
Problem
Traditional thermal interface materials for LED packaging have low heat conductivity and can generate residue or outgas, making them unsuitable for high-power LED applications due to their low viscosity and material degradation.
Innovation Solution
A high heat conductivity, insulative, and adhesive material composed of a polymeric component with thermoset epoxy resin and polymeric modifier, combined with a heat conductive filler and curing agent, which is capable of curing below 140°C, providing improved impact resistance and thermal management without generating residue or outgas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional thermal interface materials are used, then adhesion is provided, but heat conductivity is low and residue or outgassing occurs
Solution Approach 1:
The patent uses a composite material system consisting of thermoset epoxy resin as the base polymer, polymeric modifier for impact resistance, heat conductive filler particles for thermal conductivity, and curing agent for crosslinking. This composite structure combines the adhesive properties of epoxy with the thermal conductivity of filler particles while avoiding the degradation issues of pure organic polymers.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the thermal interface material by controlling the particle size, shape, and distribution of heat conductive filler; adjusting the ratio of polymeric modifier to epoxy resin; and optimizing curing conditions. These parameter changes enable the material to achieve high thermal conductivity while maintaining adhesion and eliminating harmful degradation products.
2Area of stationary object
If FR4 resin layer is used for heat transfer, then large heat dissipation area is achieved, but heat conductivity coefficient is low
Solution Approach 1:
The patent applies local quality enhancement by incorporating heat conductive filler particles specifically in the regions where thermal transfer is most critical, such as near the LED heat source and along the thermal path to the heat sink. This localized concentration of high-conductivity material optimizes heat transfer efficiency without requiring uniform material properties throughout the entire structure.
3Temperature
If silicon polymer is used as thermal interface material, then high temperature resistance is achieved, but liquefied residue or outgassing occurs after degradation
Solution Approach 1:
The patent employs a thermoset epoxy resin system that, while not permanently indestructible, provides sufficient service life for the intended application without degrading into harmful substances. The crosslinked network structure of the cured epoxy ensures long-term stability and resistance to thermal degradation, effectively replacing the problematic silicon polymer while maintaining temperature resistance.
4Device complexity
If traditional LED packaging with metal lead frame is used, then simple structure is maintained, but thermal resistance is very high
Solution Approach 1:
The patent merges multiple functions into a single integrated component: the thermal interface material simultaneously provides adhesion between the LED package and substrate, serves as a thermal conduction path through heat conductive filler, and offers electrical insulation. This consolidation eliminates the need for separate adhesive layers and thermal interface materials, reducing overall thermal resistance while maintaining structural simplicity.
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 adhesive material achieves thermal resistance below 0.5°C/W and adhesive strength greater than 300 g/cm², ensuring efficient heat transfer and durability for LED applications without the drawbacks of traditional materials.
Implementation Method 1
The adhesive material has a heat conductivity greater than 3 W/m-K
Implementation Method 2
The curing agent is capable of curing the thermoset epoxy resin at a temperature below 140° C.
Data Source
AI summary
An adhesive material comprises a polymeric component, a heat conductive filler and a curing agent. The polymeric component comprises 30%-60% by volume of the adhesive material, and comprises thermoset epoxy resin and polymeric modifier configured to improve impact resistance of the thermoset epoxy resin. The polymeric modifier comprises thermoplastic, rubber or the mixture thereof. The polymeric modifier comprises 4%-45% by volume of the polymeric component. The heat conductive filler is evenly dispersed in the polymeric component, and comprises 40%-70% by volume of the adhesive material. The curing agent is capable of curing the thermoset epoxy resin at a temperature below 140° C. The adhesive material has a heat conductivity greater than 3 W/m-K.