Feedthrough Shielding for Implantable Medical Devices

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Solution Overview

Problem

Implantable medical devices face challenges in shielding electrical signals from interference due to fluid ingress, which creates conductive leakage paths between feedthrough pins, leading to electrical interference and noise, particularly between low voltage input signals and high voltage stimulation signals.

Innovation Solution

An electrical shielding member is positioned on the outer surface of the insulator to provide a grounding barrier between feedthrough pins, ensuring that any fluid ingress path crosses the shielding member, shorting interfering signals to a ground element and preventing interference between pins.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple feedthrough pins are used to carry signals between external components and internal electronics, then device functionality is improved, but electrical interference between pins increases due to conductive leakage paths from fluid ingress

Engineering Contradiction:

Improvedevice functionalityVSAvoidelectrical interference

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

An electrical shielding member is introduced as an intermediary conductive barrier between feedthrough pins. This shielding member intercepts conductive leakage paths from fluid ingress and redirects them to a ground element, preventing direct electrical interference between signal-carrying pins while maintaining the necessary signal transmission functionality

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful effect of fluid ingress creating conductive leakage paths into a beneficial grounding mechanism. By positioning the shielding member to intercept these leakage paths, the previously harmful conductive paths are redirected to safely discharge interfering signals to ground, eliminating the interference while preserving signal transmission

Inventive Principle:

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

2Volume of moving object

If feedthrough pins are positioned closer together to reduce device size, then device compactness is improved, but electrical interference between pins increases due to shorter insulation distances

Engineering Contradiction:

Improvedevice sizeVSAvoidelectrical interference

Core Design Contradiction:

Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The electrical shielding member serves as an intermediary barrier that compensates for reduced insulation distances. By placing this conductive shielding between closely-spaced feedthrough pins, the patent enables compact positioning while the shielding intercepts and redirects any potential leakage paths to ground, preventing interference despite the shorter distances

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If traditional insulation methods are used without additional shielding, then device complexity is reduced, but reliability decreases due to susceptibility to electrical interference from fluid ingress

Engineering Contradiction:

Improveshielding structureVSAvoidsignal integrity

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

A relatively simple electrical shielding member is introduced as an intermediary protective element. This shielding component, connected to ground, provides reliable protection against electrical interference from fluid ingress with minimal added complexity, as it can be implemented as a straightforward conductive barrier without complex mechanisms

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The electrical shielding member is positioned in advance to preemptively intercept potential conductive leakage paths before they can cause interference between feedthrough pins. This preliminary protective measure ensures reliability by preventing interference rather than attempting to correct it after occurrence

Inventive Principle:

Principle #10Preliminary action

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 electrical shielding member effectively reduces electrical interference and noise, enhancing the reliability of implantable medical devices by isolating susceptible and inducing signals, thereby improving signal integrity and reducing audible noise for recipients.

Implementation Method 1

an electrical shielding member positioned on the outer surface of the insulator, wherein the electrical shielding member is configured to provide a grounding barrier between the first and second feedthrough pins

Methodology Applied

Scientific EffectElectrical shielding: Faraday Cage

Data Source

PatentUS11896835B2Electrical shielding in implantable medical devices

Publication Date: 2024.02.13 COCHLEAR LIMITED

AI summary

Presented herein are implantable medical devices that include an insulator extending through a hermetically-sealed biocompatible housing. A plurality of feedthrough pins, which include at least a first feedthrough pin, a second feedthrough pin, and at least one ground feedthrough pin extend through the insulator. An electrically shielding member is disposed at the outer surface of the insulator so as to provide a grounding barrier between the first and second feedthrough pins.