Integrated PCB Electromagnetic Shield via Conductive Chassis

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Solution Overview

Problem

Conventional electromagnetic shielding solutions for printed circuit boards are costly, bulky, and time-consuming to install, especially when they need to protect sensitive components from interference while allowing the transmission of electromagnetic signals, as in devices with antennas or transceivers.

Innovation Solution

A Faraday cage is formed by a conductive chassis and ground layer with contact pads and dimples, integrated into the substrate, which provides electromagnetic shielding without additional components, allowing signal transmission from components outside the shielded area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional electromagnetic shield covers are mounted to a printed circuit board, then electromagnetic interference protection is improved, but device complexity and installation time increase

Engineering Contradiction:
Improveelectromagnetic interference protectionVSAvoidshield structure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the electromagnetic shield with the printed circuit board by integrating conductive shielding elements directly into the PCB structure. The shield is formed as part of the PCB substrate itself, eliminating separate shield covers and reducing overall device complexity while maintaining EMI protection effectiveness.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The printed circuit board serves multiple functions: it provides mechanical support for components, electrical connections through traces, and electromagnetic shielding through integrated conductive elements. This multi-functionality eliminates the need for separate dedicated shield structures, reducing complexity and installation requirements.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Object-affected harmful factors

If conventional electromagnetic shield covers are mounted to a printed circuit board, then electromagnetic interference protection is improved, but installation time increases

Engineering Contradiction:
Improveelectromagnetic interference protectionVSAvoidinstallation time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

By combining the shield structure with the PCB manufacturing process itself, the shield is created during board fabrication rather than being added as a separate component. This integration eliminates the need for separate installation steps, significantly reducing assembly time while maintaining effective EMI protection.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The electromagnetic shielding structure is prepared and integrated into the PCB during the manufacturing process before the board is assembled into the final device. This preliminary action ensures the shield is already in place and requires no additional installation time during device assembly.

Inventive Principle:
Principle #10Preliminary action

3Object-affected harmful factors

If an electromagnetic shield is provided to protect sensitive components, then electromagnetic interference protection is improved, but material costs increase

Engineering Contradiction:
Improveelectromagnetic interference protectionVSAvoidmaterial cost
Core Design Contradiction:
Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The shield structure is merged with the PCB substrate, utilizing the same base materials and manufacturing processes. This eliminates the need for additional expensive shield materials and reduces overall material costs while providing effective EMI protection.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The PCB substrate and its conductive traces serve dual purposes: providing electrical connectivity and providing electromagnetic shielding. This multi-functionality eliminates the need for separate shield materials, reducing material costs while maintaining protection effectiveness.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Object-affected harmful factors

If an electromagnetic shield is provided for a printed circuit board including an antenna, then electromagnetic interference protection is improved, but device complexity increases

Engineering Contradiction:
Improveelectromagnetic interference protectionVSAvoidshield structure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The electromagnetic shielding is applied locally around the antenna and sensitive components rather than covering the entire PCB. Conductive shielding elements are strategically positioned only where EMI protection is needed, reducing overall structure complexity while maintaining effective protection for critical areas.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The shield structure is merged with the PCB and antenna assembly, using the same substrate and integration processes. This unified approach eliminates the need for separate shield components and complex assembly procedures, reducing device complexity while providing targeted EMI protection for the antenna system.

Inventive Principle:
Principle #5Merging (Combining)

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

This solution reduces material and installation costs by integrating shielding into the substrate construction, effectively blocking electromagnetic interference while permitting signal transmission, thus simplifying and cost-effectively protecting electronic devices from interference.

Implementation Method 1

A Faraday cage is formed by a conductive chassis and ground layer with contact pads and dimples, integrated into the substrate, which provides electromagnetic shielding without additional components

Methodology Applied
Scientific EffectFaraday cage: Faraday Cage

Implementation Method 2

conventional electromagnetic shield covers mounted to a printed circuit board can be undesirably bulky and time consuming to install

Methodology Applied
Scientific EffectElectromagnetic shielding: Conduction (electrical)

Data Source

PatentEP3240387B1Electromagnetic shield for an electronic device
Publication Date: 2021.02.17 HARMAN INT IND INC
  • EP3240387B1 patent drawingFigure 1
  • EP3240387B1 patent drawingFigure 2
  • EP3240387B1 patent drawingFigure 3

AI summary

An electronic device including a substrate having opposing top and bottom surfaces is provided. A ground layer is disposed in the substrate. An electrically conductive chassis has a mounting surface to receive the bottom surface of the substrate and is in electrical contact with the ground layer by a ground stitch via. An electromagnetic shield is defined by the ground layer, the ground stitch via and the chassis to enclose the bottom surface of the substrate and protect the bottom surface from electromagnetic interference. A non-conductive cover is assembled to the substrate in tension so that an interior surface of the cover applies a force to the top surface of the substrate thereby ensuring the chassis maintains in electrical contact with the ground layer.