Self-Adaptive Thin-Film RF Shielding for Optical Transparency

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Solution Overview

Problem

Existing electromagnetic shielding screens for vehicles with optical sensors have predefined and constant shielding effectiveness, failing to adapt dynamically to varying electromagnetic field strengths, requiring external power for activation, and compromising optical transparency.

Innovation Solution

A self-adaptive electromagnetic shielding device with a switchable RF shielding mesh surrounded by insulator-metal transition material, activated by a susceptor element that converts electromagnetic energy into heat to switch the material's conductivity state, automatically adjusting shielding based on incident energy levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a predefined and constant shielding effectiveness is used, then the shielding screen provides stable electromagnetic protection, but it cannot adapt dynamically to varying electromagnetic field strengths

Engineering Contradiction:
Improveadaptability to electromagnetic field strengthVSAvoidcomplexity of shielding mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The shielding screen transitions from a static, predefined configuration to a dynamic system that automatically adjusts its shielding effectiveness. The insulator-metal transition material changes its electrical conductivity in response to electromagnetic field strength, enabling the mesh to adapt its shielding properties without mechanical movement or external control.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the electrical conductivity parameter of the insulator-metal transition material based on electromagnetic field intensity. When the electromagnetic field exceeds a threshold, the material transitions from insulating to conductive state, thereby changing the contact impedance and adjusting the shielding effectiveness dynamically.

Inventive Principle:
Principle #35Parameter changes

2Extent of automation

If switchable RF shielding with localized components or insulator-metal transition materials is used, then the shielding effectiveness can be modulated, but external power supply or command is required for activation

Engineering Contradiction:
Improveautomatic activation of shieldingVSAvoidpower consumption for activation
Core Design Contradiction:
Extent of automationVSUse of energy by moving object

Solution Approach 1:

The shielding system becomes self-activating by utilizing the incident electromagnetic energy itself as the trigger mechanism. The insulator-metal transition material automatically changes state in response to the electromagnetic field strength, eliminating the need for external power supplies, commands, or control systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The incident electromagnetic energy, which represents a harmful attack or interference, is converted into the activation mechanism for the shielding system. The electromagnetic field that threatens the sensor also provides the energy needed to trigger the protective response, turning the threat into the solution.

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

3Object-affected harmful factors

If a metal mesh with micrometric pitch is used for shielding, then electromagnetic protection is effective, but optical transparency is reduced

Engineering Contradiction:
Improveelectromagnetic radiation protectionVSAvoidoptical transparency
Core Design Contradiction:
Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The invention uses a composite structure combining a metal mesh with insulator-metal transition material. This composite allows the system to achieve both electromagnetic shielding effectiveness and optical transparency by leveraging the different properties of the constituent materials in their respective operational states.

Inventive Principle:
Principle #40Composite materials

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 device provides automatic transition between transparent and shielding states, maintaining high optical transparency and effective electromagnetic protection across a wide frequency range without external power, enhancing operational efficiency and adaptability.

Implementation Method 1

comprising a susceptor element, arranged opposite or in contact with said insulator-metal transition material and adapted to transform incident electromagnetic energy into a quantity of activation heat of said insulator-metal transition material

Methodology Applied
Scientific EffectElectromagnetic energy to heat transformation: Dielectric Heating

Implementation Method 2

a susceptor element, arranged opposite or in contact with said insulator-metal transition material and adapted to transform incident electromagnetic energy into a quantity of activation heat

Methodology Applied
Scientific EffectElectromagnetic energy absorption: Absorption (EM radiation)

Data Source

PatentEP4423558B1Self-adaptive thin-film electromagnetic shielding screen
Publication Date: 2025.08.27 SAFRAN ELECTRONICS & DEFENSE (FR)
  • EP4423558B1 patent drawingFigure 1A~1B
  • EP4423558B1 patent drawingFigure 1C~2
  • EP4423558B1 patent drawingFigure 3~4A

AI summary

The invention relates to a self-adaptive shielding device for a lens or a window (1) of a piece of equipment provided with an electrically conductive enclosure (10) enclosing an optical or RF sensor (20) behind said lens or said window, said device comprising, on at least one face of said lens or said window, a shielding screen comprising a switchable RF shielding mesh (2) with a micrometric pitch at least partially surrounded by an edge of metal-insulator transition material (3) arranged between said mesh and an electrically conductive envelope (11) for shielding said equipment, comprising a susceptor element (5) arranged opposite or in contact with said metal-insulator transition material and suitable for transforming incident electromagnetic energy (RFH) into an amount of heat for activating said metal-insulator transition material (3, 3a, 31), said susceptor element being dimensioned to cause a transition to the conductive state of said metal-insulator transition material (3, 3a, 31, 31a) by means of said electromagnetic energy so as to electrically connect said mesh to said electrically conductive envelope when the incident electromagnetic energy exceeds a given threshold.