Flexible Thermally Conductive Polymeric Substrate for LED Heat Dissipation
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Solution Overview
Problem
Thermally conductive substrates in electronic devices, such as LEDs, face challenges in efficiently dissipating heat due to barriers in heat transfer, and existing materials often become brittle with high thermal conductivity particle loading, making them unsuitable for self-supporting layers in manufacturing processes.
Innovation Solution
A flexible thermally conductive polymeric layer comprising an epoxy resin and long-strand nonwoven material, which can withstand high temperatures and maintain structural integrity, allowing for self-supporting properties and simultaneous etching of metal layers, thereby enhancing heat dissipation and manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermally conductive filler is added to the polymeric layer, then thermal conductivity is improved, but the polymeric layer becomes brittle and loses structural integrity
Solution Approach 1:
The patent uses a composite material system consisting of a polymeric matrix combined with thermally conductive filler particles (such as aluminum oxide, aluminum nitride, or boron nitride). This composite structure allows the material to simultaneously exhibit both mechanical properties from the polymer and thermal conductivity from the filler, resolving the contradiction between thermal performance and structural integrity
Solution Approach 2:
The patent optimizes the concentration and distribution of thermally conductive filler within the polymeric layer, maintaining filler content at levels that enhance thermal conductivity without exceeding the threshold that would cause excessive brittleness. This parameter optimization allows the layer to remain self-supporting while achieving improved heat transfer
2Temperature
If the polymeric layer is made thin to reduce heat transfer barrier, then thermal performance is improved, but the layer loses self-supporting capability
Solution Approach 1:
The incorporation of thermally conductive filler within the thin polymeric matrix creates a composite structure that enhances both thermal conductivity and mechanical reinforcement. The filler particles act as structural enhancers that allow the thin layer to maintain self-supporting properties despite reduced thickness
Solution Approach 2:
The patent employs a thin film structure optimized for heat transfer applications, where the polymeric layer is sufficiently thin to minimize thermal resistance but reinforced with conductive filler to maintain mechanical integrity and self-supporting capability during manufacturing and operation
3Ease of manufacture
If the polymeric layer is exposed to lead-free solder flow process temperatures, then soldering is completed, but the polymeric layer may melt or degrade
Solution Approach 1:
The patent selects polymeric materials and curing conditions that result in a glass transition temperature and decomposition temperature well above the lead-free solder flow process temperature (280°C for 90 seconds). This parameter selection ensures the polymeric layer maintains dimensional stability and does not melt or degrade during the soldering process
Solution Approach 2:
The polymeric layer is pre-cured to achieve maximum thermal and mechanical stability before undergoing the soldering process. This prior curing creates a cross-linked network structure that provides thermal resistance and dimensional stability, cushioning the material against degradation during subsequent high-temperature exposure
4Reliability
If electrically conductive filler is added to achieve electrical conductivity, then electrical resistance is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent employs filler materials that provide both thermal conductivity and electrical conductivity simultaneously (such as certain metal oxides or carbon-based materials). This multi-functional approach allows a single filler addition to address both thermal management and electrical grounding requirements, reducing manufacturing complexity compared to separate treatments
Solution Approach 2:
The composite polymeric layer incorporates conductive filler that creates percolation pathways for electrical conduction while maintaining thermal conductivity. This single composite structure serves dual purposes of heat dissipation and electrical grounding, simplifying the overall device architecture and 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 solution provides a strong, flexible, and thermally conductive polymeric layer that effectively dissipates heat and supports metal layer etching, reducing manufacturing costs and improving thermal conductivity while maintaining mechanical strength.
Implementation Method 1
the polymeric nonwoven material can withstand, without melting and preferably without any property changes, temperatures of at least about 280° C. for at least 90 seconds
Implementation Method 2
The thin polymeric layer helps to minimize the barrier to heat transfer, for example from the LEDs on one side of the polymeric layer to a thermally conductive layer on the opposite side of the polymeric layer
Data Source
AI summary
A thermally conductive article including a polymeric layer comprising a nonwoven polymeric material. In particular, a flexible thermally conductive polymeric layer comprising an epoxy resin and a long-strand polymeric nonwoven material embedded in the epoxy resin. The polymeric nonwoven material may be heat stable at about 280 C.