EMI Shielding TIM Composite With Magnetic Filler Alignment
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Solution Overview
Problem
Existing thermal interface materials (TIMs) face challenges in achieving high thermal conductivity and electromagnetic interference (EMI) shielding while being cost-effective, with conventional methods limited by the need for high ceramic filler volumes and inefficient alignment of non-symmetrical materials.
Innovation Solution
A composite thermal interface material comprising self-aligned carbon-based materials with superparamagnetic particles, aligned under a magnetic field, and a blend of dielectric isotropic heat transfer materials, achieving thermal conductivities of 30 W/mK through-plane and 10 W/mK in-plane, with EMI shielding properties enhanced by superparamagnetic particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional TIMs use high volume fraction of ceramic fillers to achieve thermal conductivity of 1-10 W/mK, then thermal conductivity is improved, but the material becomes less flexible and more expensive
Solution Approach 1:
The patent uses a composite material system combining polymer matrix with ceramic fillers (alumina, aluminum nitride, boron nitride) and carbon-based materials (graphite, carbon fiber, carbon nanotubes). This composite approach achieves high thermal conductivity (1-10 W/mK) while maintaining flexibility through the polymer matrix, resolving the contradiction between thermal performance and mechanical properties
Solution Approach 2:
The patent creates regions of high thermal conductivity pathways through aligned carbon-based materials and ceramic filler clusters within the polymer matrix. This local concentration of thermally conductive phases provides efficient heat transfer routes without requiring uniform high filler volume throughout the entire material, thus maintaining flexibility while achieving high thermal conductivity
2Temperature
If highly thermally conductive materials like carbon nanotubes, carbon fibers and graphene are used to improve thermal conductivity, then thermal conductivity is enhanced, but the cost becomes prohibitive
Solution Approach 1:
The patent modifies the parameters of conventional materials by aligning carbon-based materials (graphite, carbon fiber) and ceramic fillers in specific orientations using magnetic fields or extrusion processes. This alignment creates preferential thermal conductivity pathways that enhance heat transfer efficiency without requiring the use of expensive materials like graphene or carbon nanotubes, thus achieving high thermal conductivity at lower cost
Solution Approach 2:
The patent uses polymer matrix as an intermediary material that binds together cheaper ceramic fillers and carbon-based materials, creating a composite structure that achieves high thermal conductivity through the synergistic arrangement of these materials rather than relying on expensive individual components
3Shape
If electrostatic method is used to align carbon fiber, then alignment is achieved, but the method is not suitable for non-symmetrical materials like graphite flake
Solution Approach 1:
The patent replaces the electrostatic alignment method with magnetic field-based alignment or mechanical extrusion alignment. These alternative methods are effective for non-symmetrical materials like graphite flakes, which do not respond well to electrostatic forces. The magnetic field aligns materials with magnetic properties, while extrusion provides mechanical alignment during processing, thus achieving versatility across different material types
4Quantity of substance
If heat conductive particles are dispersed by gravity in liquid matrix, then dispersion is achieved, but the method is restricted by liquid state characteristic and lacks EMI shielding properties
Solution Approach 1:
The patent changes the state of the matrix from liquid to solid polymer, and modifies the dispersion mechanism from gravity-based to magnetic field-based or extrusion-based alignment. This parameter change enables the material to maintain particle dispersion while gaining structural integrity and EMI shielding properties through the incorporation of conductive carbon-based materials in aligned configurations
Solution Approach 2:
The patent creates a composite material system combining polymer matrix with ceramic fillers and carbon-based materials that provides both thermal conductivity and EMI shielding properties. The aligned structure of carbon-based materials creates conductive pathways for EMI shielding while maintaining particle dispersion, thus resolving the limitation of conventional gravity-based dispersion methods
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 composite provides efficient heat dissipation and superior EMI shielding with reduced ceramic filler volume, maintaining flexibility and fire retardancy, suitable for high thermal conductivity and EMI shielding applications.
Implementation Method 1
self-aligned, carbon-based materials with superparamagnetic particles, aligned under a magnetic field
Implementation Method 2
aligned under a magnetic field, achieving thermal conductivities of 30 W/mK through-plane and 10 W/mK in-plane
Implementation Method 3
thermal conductivities of 30 W/mK through-plane and 10 W/mK in-plane, achieving efficient heat dissipation
Data Source
AI summary
The present invention provides an EMI shielding device including a flame retarding, thermal interface material composite with a through plane thermal conductivity of no less than 30 W/mK and a dielectric withstanding voltage of no less than 1 kV/mm, where the composite includes at least one dielectric layer of self-aligned, carbon-based materials associated with superparamagnetic particles and at least one layer of fillers including a blend of dielectric heat transfer materials with a thermal or UV curable polymer or phase change polymer. The anisotropic heat transfer carbon-based materials associated with superparamagnetic materials are aligned under a low magnetic field strength of less than 1 Tesla to an orientation that results in a high thermal conductivity direction which can conduct the maximum heat from the adjacent device of the present composite. The present invention also provides a method for preparing the composite.