EMI Absorbing Paint for Electronic Enclosures

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Solution Overview

Problem

Existing EMI shielding methods for electronic equipment are cumbersome, costly, and ineffective at high frequencies due to aperture-related resonance and leakage issues, particularly as frequencies exceed 10 GHz, necessitating a simpler and more cost-effective solution to suppress electromagnetic interference.

Innovation Solution

Applying a thin layer of electromagnetic absorbing paint with a liquid matrix and ferromagnetic particles to the inner surface of a conductive enclosure, which covers 90% or more of the surface, to attenuate high-frequency EMI emissions without the need for additional shielding or adhesives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional EMI shielding methods are used with apertures and seams, then the enclosure can accommodate ventilation and connection ports, but EMI leakage and resonance increase at high frequencies

Engineering Contradiction:

Improveenclosure functionalityVSAvoidEMI leakage

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies EMI-absorbing material specifically at aperture locations and problematic areas rather than uniformly throughout the enclosure. This targeted approach addresses EMI leakage at critical points while maintaining the necessary apertures for ventilation and connections, thus preserving enclosure functionality without compromising shielding effectiveness.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent converts the harmful effect of apertures (which cause EMI leakage) into a beneficial solution by placing EMI-absorbing material at these locations. The apertures remain necessary for functionality, but the absorbing material transforms them from EMI leakage sources into controlled transition zones that maintain shielding effectiveness.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If absorbing pads are placed around specific components to suppress EMI, then EMI emission from identified sources is reduced, but the method becomes cumbersome and time-consuming

Engineering Contradiction:

ImproveEMI emissionVSAvoidshielding implementation

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges multiple individual absorbing pad applications into a single integrated EMI-absorbing coating system applied to the enclosure interior surfaces. This consolidation maintains the EMI suppression function while dramatically reducing implementation complexity, eliminating the need to individually identify and treat each emission source.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The EMI-absorbing coating serves multiple functions simultaneously: it suppresses EMI from all components within the enclosure, lines the entire interior surface for comprehensive coverage, and can be applied in a single manufacturing step. This multi-functionality replaces the need for multiple separate absorbing pads placed at specific locations.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If more material and multiple layers are used for EMI suppression, then shielding effectiveness improves, but material costs and labor requirements increase

Engineering Contradiction:

ImproveEMI suppression effectivenessVSAvoidmaterial consumption

Core Design Contradiction:

Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The patent optimizes the thickness and material composition parameters of the EMI-absorbing coating to achieve effective shielding with minimal material consumption. By carefully selecting and tuning these parameters, the solution maintains high shielding effectiveness while using far less material than traditional multiple-layer approaches or numerous individual absorbing pads.

Inventive Principle:

Principle #35Parameter changes

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 paint significantly reduces EMI emissions across a broad frequency range, including GHz frequencies, by dissipating electromagnetic energy, thus enhancing shielding effectiveness and reducing material and labor costs, with a single layer being sufficient for effective attenuation.

Implementation Method 1

electromagnetic absorbing paint... to attenuate high-frequency EMI emissions... by dissipating electromagnetic energy

Methodology Applied

Scientific EffectElectromagnetic absorption: Absorption (EM radiation)

Implementation Method 2

The electromagnetic absorbing paint comprises a liquid matrix and ferromagnetic particles

Methodology Applied

Scientific EffectMagnetic hysteresis: Magnetic Hysteresis

Data Source

PatentUS11503751B2Method, system and paint for EMI suppression

Publication Date: 2022.11.15 MELLANOX TECHNOLOGIES LTD(IL)

AI summary

A method, system and paint for suppressing emission of high frequency electromagnetic radiation from an electronic system, the electronic system including at least one power supply unit, at least one printed circuit board (PCB) and at least one integrated circuit are provided. The method includes providing an electrically conductive housing configured to accommodate and encase the electronic system, the housing having an inner conductive surface, and applying a layer of an electromagnetic absorbing paint to the inner conductive surface of the housing to substantially cover the inner surface by the layer, the electromagnetic absorbing paint comprises a liquid matrix and an electromagnetic absorbing material.