Carbon Nanotube Shielding Layer for PCB EMI Reduction
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Solution Overview
Problem
Increasing electromagnetic interference (EMI) in multi-layer printed circuit boards due to higher circuit density is not effectively addressed by additional electromagnetic shielding layers, which also increase thickness and decrease circuit density.
Innovation Solution
An insulating film with a B-Stage polymer structure, featuring a sandwiched electromagnetic shielding layer composed of parallel carbon nanotube films, which are laminated to reduce EMI without adding extra shielding layers, while maintaining circuit density and enabling heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If additional electromagnetic shielding layers are employed to reduce EMI, then electromagnetic interference is reduced, but thickness increases and circuit density decreases
Solution Approach 1:
The patent changes the material parameter of the shielding layer from traditional metal to carbon nanotubes, which have superior electromagnetic shielding properties per unit thickness. This allows achieving the same EMI reduction with significantly reduced thickness, resolving the contradiction between EMI protection and thickness reduction
Solution Approach 2:
The patent uses composite material structure combining carbon nanotubes with polymer matrices to create an electromagnetic shielding layer that achieves high shielding effectiveness while maintaining thin profile. The composite structure allows the shielding layer to provide EMI protection without the thickness penalty of traditional metal shields
2Object-affected harmful factors
If additional electromagnetic shielding layers are employed to reduce EMI, then electromagnetic interference is reduced, but circuit density decreases
Solution Approach 1:
By changing the shielding material to carbon nanotubes with higher specific shielding effectiveness, the patent reduces the required shielding layer thickness, thereby freeing up space for additional circuit layers and improving overall circuit density while maintaining EMI protection
Solution Approach 2:
The patent integrates electromagnetic shielding functionality into the insulating film layer rather than adding separate shielding layers, effectively utilizing the vertical dimension of the PCB structure to combine insulation and EMI shielding functions, thus preserving circuit density
3Object-affected harmful factors
If carbon nanotube films are used in the electromagnetic shielding layer, then EMI is reduced and heat dissipation is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs preliminary action by forming carbon nanotube arrays on substrates before lamination, allowing the nanotubes to be pre-aligned and organized in a controlled manner. This preliminary structuring simplifies the subsequent lamination process and ensures consistent shielding performance while managing manufacturing complexity
Solution Approach 2:
The electromagnetic shielding layer is segmented into multiple carbon nanotube films that are laminated together, with each film containing carbon nanotubes oriented in specific directions. This segmentation allows for modular manufacturing and assembly while achieving comprehensive EMI shielding and heat dissipation
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 effectively reduces EMI between electronic components, allows for higher component density, and efficiently dissipates heat in printed circuit boards, enhancing their performance without increasing thickness.
Implementation Method 1
an electromagnetic shielding layer (i.e. a copper layer without circuit formed therein) may be employed in printed circuit boards
Implementation Method 2
The electromagnetic shielding layer includes a number of carbon nanotube films that are substantially parallel to the first and second polymer layer. Each of the carbon nanotube films includes a number of carbon nanotubes that are substantially parallel to each other
Implementation Method 3
efficiently dissipates heat in printed circuit boards, enhancing their performance without increasing thickness
Data Source
AI summary
An insulating film includes a first polymer layer, a second polymer layer and an electromagnetic shielding layer sandwiched between the first polymer layer and the second polymer layer. The electromagnetic shielding layer includes a number of carbon nanotube films that are substantially parallel to the first and second polymer layer. Each of the carbon nanotube films includes a number of carbon nanotubes that are substantially parallel to each other. The insulating film can provide anti-EMI effect in printed circuit boards without employing additional electromagnetic shielding layers.