Conformal Shielding for Circuit Boards

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Solution Overview

Problem

The increasing complexity and reduced space on circuit boards due to smaller electronic devices lead to challenges with radio frequency and electromagnetic interference (RFI/EMI), where conventional box-type shields are bulky and inefficient, especially when applied to tightly packed circuit components.

Innovation Solution

A patterned conformal structure comprising a dielectric and metallic layer, where the metallic layer is patterned using laser ablation to form localized shielding structures and interconnects, eliminating the need for a masking layer and allowing for tighter component packing, while providing effective shielding against RFI/EMI and serving as electrical and thermal pathways.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional box-type shields are used to prevent RFI/EMI interference, then shielding effectiveness is improved, but device thickness and space utilization deteriorate due to bulky structure and unused air gaps

Engineering Contradiction:
ImproveRFI/EMI interferenceVSAvoiddevice thickness
Core Design Contradiction:
Object-affected harmful factorsVSLength of stationary object

Solution Approach 1:

The patent applies conformal shielding structures that conform to the circuit board surface topology, replacing rigid box-type shields with thin-film metal layers deposited over dielectric material. This creates a conformal shield that follows the board surface, eliminating unused air gaps and reducing overall device thickness while maintaining shielding effectiveness.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent transitions from three-dimensional box-type shields to two-dimensional conformal surface shields. By depositing metal layers conformally over the circuit board surface, the shielding function is achieved in a planar dimension rather than requiring vertical enclosure space, thereby reducing device thickness.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If masking layers are used to pattern metal layers for conformal shielding, then shielding structure formation is simplified, but manufacturing precision deteriorates for tightly packed circuit components

Engineering Contradiction:
Improvepatterned metal layer formationVSAvoidpattern accuracy for tightly packed components
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical masking process with direct laser ablation of the metal layer. Instead of using physical masks that require alignment and application steps, a laser directly writes the shield patterns by ablatively removing metal in desired areas, achieving higher precision for tightly packed components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and eliminates the masking layer from the manufacturing process. By using laser ablation to directly pattern the metal layer, the intermediate masking step is removed entirely, simplifying the manufacturing process while improving precision for dense component layouts.

Inventive Principle:
Principle #2Taking out (Extraction)

3Area of stationary object

If circuit components are tightly packed to reduce device size, then space utilization is improved, but RFI/EMI interference between adjacent components increases

Engineering Contradiction:
Improvecircuit board space utilizationVSAvoidinter-component electromagnetic interference
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent implements localized conformal shielding structures that are selectively applied over specific circuit components or signal traces. Rather than uniform shielding across the entire board, shields are created only where needed based on the local electromagnetic interference risk, enabling tight component packing while providing targeted interference protection.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent divides the shielding function into discrete localized segments rather than using continuous bulk shielding. Individual conformal shield structures are created around specific components or signal paths, allowing tight component placement while providing isolated electromagnetic protection where required.

Inventive Principle:
Principle #1Segmentation

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 enables efficient shielding of tightly packed circuit components, reducing interference and allowing for improved heat dissipation, thus increasing packing density and reducing the overall thickness of electronic devices.

Implementation Method 1

a laser is directed to points on dielectric coating above contact pads 22 and package feed thrus 25, so as to drill through (i.e., burn) any dielectric material positioned thereover

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentEP2268117B1System and method of forming isolated conformal shielding areas
Publication Date: 2018.03.14 GENERAL ELECTRIC CO
  • EP2268117B1 patent drawingFigure 1
  • EP2268117B1 patent drawingFigure 2
  • EP2268117B1 patent drawingFigure 3A~3B

AI summary

A system and method of forming a patterned conformal structure (10) for an electrical system (12) is disclosed. The conformal structure (10) includes a dielectric coating (18) positioned on an electrical system (12) having circuit components (16) mounted thereon, the dielectric coating (18) shaped to conform to a surface of the electrical system (12) and having a plurality of openings (20) therein positioned over contact pads (22) on the surface of the electrical system. The conformal structure (10) also includes a conductive coating (24) layered on the dielectric coating (18) and on the contact pads (22) such that an electrical connection is formed between the conductive coating (24) and the contact pads (22). The dielectric coating (18) and the conductive coating (24) have a plurality of overlapping pathway openings (27) formed therethrough to isolate a respective shielding area (26) of the conformal structure over desired circuit components (16) or groups of circuit components.