Multilayer Thin Film Board Level Shield for EMI Reduction
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Solution Overview
Problem
There is a need for board level shields that are very thin and lightweight to provide effective electromagnetic interference (EMI) shielding in densely populated electronic devices, such as wearable electronics, while minimizing space and weight constraints.
Innovation Solution
Multilayer thin film board level shields with electrically-conductive shielding materials, such as metal layers, coated on dielectric materials like plastics, are applied directly to PCB components, offering shielding effectiveness of up to 40 dB in a thickness of 15 microns or less, using methods like laser welding or sonic welding without requiring bond pads or frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional shields are used to provide EMI shielding, then shielding effectiveness is achieved, but thickness and weight increase
Solution Approach 1:
The patent applies thin film shielding materials (15 microns or less thickness) directly to PCB components. These thin films provide effective EMI shielding (up to 40 dB) while maintaining extreme lightness and flexibility, resolving the contradiction between shielding effectiveness and weight.
Solution Approach 2:
The patent uses composite material structures combining dielectric layers with conductive shielding layers. This composite approach achieves high shielding effectiveness through material composition rather than thickness, significantly reducing the weight compared to traditional solid shields.
2Reliability
If traditional shields are used to provide EMI shielding, then shielding effectiveness is achieved, but space consumption increases
Solution Approach 1:
The thin film structure (15 microns or less) conformally coats PCB components, providing comprehensive EMI shielding within the existing device footprint without requiring additional space, thus resolving the contradiction between shielding effectiveness and volume.
Solution Approach 2:
The patent transitions from volumetric shields to surface-based thin film coatings. This dimensional shift from 3D volume to 2D surface application provides shielding effectiveness without consuming additional device volume, enabling integration in densely populated electronics.
3Stability of the object's composition
If bond pads and frames are used for shield attachment, then mechanical stability is achieved, but device complexity increases
Solution Approach 1:
The thin film shielding material is designed to be self-adhering through conformal coating and melting processes. The material serves its own attachment function by bonding directly to the PCB substrate through heat and pressure, eliminating the need for separate bond pads, frames, or mechanical fastening structures.
Solution Approach 2:
The patent extracts and removes the complex attachment infrastructure (bond pads, frames, fasteners) from the shielding system. The simplified thin film structure attaches directly to the PCB surface, reducing device complexity while maintaining adequate mechanical stability through the coating 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
These shields effectively reduce EMI/RFI interference across a wide frequency bandwidth, including 5G frequencies, while being compact and lightweight, thus enhancing the performance and reliability of electronic devices.
Implementation Method 1
shields capable of absorbing and/or reflecting and/or redirecting EMI energy
Implementation Method 2
shields capable of absorbing and/or reflecting and/or redirecting EMI energy
Implementation Method 3
inner and outer dielectric layers (e.g., plastic layers, thin polymer films)
Implementation Method 4
using methods like laser welding or sonic welding
Implementation Method 5
using methods like laser welding or sonic welding
Data Source
AI summary
A multilayer board level shield includes an electrically-conductive shielding layer disposed between inner and outer dielectric layers. The multilayer board level shield may have an overall thickness of about 25 microns or less. The multilayer board level shield may have sufficient flexibility to be reconfigurable generally over one or more components on a substrate to thereby provide board level shielding for the one or more components. One or more dielectric joints may be defined between the printed circuit board and the outer dielectric layer that attach the multilayer board level shield to the printed circuit board.