EIT Electrode Sensor with Insulating Interface for Stable Contact
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Solution Overview
Problem
Existing electrical impedance tomography (EIT) systems face challenges in achieving stable and reliable electrical contact between electrodes and the skin, leading to variable contact impedances and crosstalk, which affects image accuracy and can cause skin irritation due to excessive pressure and friction.
Innovation Solution
An electrode sensor with an array of spaced apart individual contact elements and an interface structure featuring an electrically insulating material with conductive patterns on both sides, connected by pathways, allowing for stable and low-impedance contact while minimizing shear forces and pressure on the skin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional electrodes are placed directly on the skin, then electrical contact is established, but contact impedance becomes unstable and crosstalk occurs
Solution Approach 1:
An electrically insulating interface structure is introduced between the contact elements and the skin. This intermediary structure provides a stable mechanical interface while the conductive pathways within it establish reliable electrical contact, reducing both contact impedance variability and crosstalk between adjacent electrodes.
Solution Approach 2:
The interface structure is divided into multiple isolated conductive pathways that are spatially separated by insulating material. This segmentation prevents electrical crosstalk between adjacent contact elements while maintaining stable individual contact paths to the skin.
2Reliability
If pressure is increased to improve electrical contact, then contact impedance decreases, but skin irritation increases
Solution Approach 1:
The interface structure uses a flexible insulating layer with integrated conductive pathways that can conform to the skin surface. This flexible film design distributes contact pressure evenly across multiple points, maintaining low contact impedance without concentrating excessive force that would cause skin irritation.
Solution Approach 2:
The interface structure provides electrical conductivity only at specific localized pathways where contact is needed, while the surrounding insulating material provides mechanical support and pressure distribution. This localized conductivity approach ensures good electrical contact at contact points while minimizing overall pressure on the skin.
3Reliability
If conductive material is applied directly to skin, then electrical contact is established, but skin irritation occurs due to friction and pressure
Solution Approach 1:
The insulating interface structure acts as a mediator between the contact elements and the skin. The conductive pathways are embedded within this intermediate layer, providing electrical contact without direct application of conductive material to the skin surface, thereby reducing friction and irritation.
4Area of stationary object
If multiple electrodes are placed close together, then measurement coverage is improved, but crosstalk between electrodes increases
Solution Approach 1:
The interface structure incorporates spatially separated conductive pathways that are electrically isolated from each other by the insulating material. This segmentation allows multiple electrodes to be placed in close proximity for comprehensive measurement coverage while preventing electrical crosstalk between adjacent contact elements.
Solution Approach 2:
The insulating interface structure serves as a mediator that enables dense electrode placement by providing physical separation and electrical isolation between contact elements, allowing high spatial resolution measurements without crosstalk interference.
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 provides reliable and stable electrical contact, reduces crosstalk, and minimizes skin irritation, enabling accurate EIT measurements while being cost-effective and suitable for single-patient use.
Implementation Method 1
an interface structure for forming contact between said contact elements and the skin; said interface structure comprising an interface layer of an essentially electrically insulating or poorly electrically conducting material defining a skin contact surface on one side and an array contact surface on the other side of the interface layer, a first pattern of an electrically conducting material on the array contact surface, a second pattern of an electrically conducting material on the skin contact surface, and electrical pathways connecting the first pattern with the second pattern
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
Electrode sensor comprising an array of spaced apart individual contact elements (27`, 41), and an interface structure (30, 35) for forming contact between said contact elements and the skin; said interface structure comprising an interface layer of an essentially electrically insulating or poorly electrically conducting material (20`, 29, 37) defining a skin (31) contact surface on one side and an array contact surface on the other side of the interface layer, a first pattern of an electrically conducting material on the array contact surface, a second pattern of an electrically conducting material on the skin contact surface, and electrical pathways (21`, 39) connecting the first pattern with the second pattern; whereas, the first pattern comprises pattern elements, each individual contact element (27`, 41) comprises a contacting surface area large enough to cover several pattern elements of said first pattern when contacting the array contact surface of the interface structure, and by contacting distinct sections of the first pattern with said individual contact elements, groups of electrical pathways establish contact further with distinct sections of the second pattern, so that an individual contact element (27`, 41) defines an individual effective electrode on the skin contact surface. Method of manufacturing said electrode sensor, comprising the steps of: providing said interface structure, creating a first pattern of an electrically conducting material on its array contact surface, a second pattern of an electrically conducting material on its skin contact surface, electrically conducting pathways connecting the first pattern with the second pattern, and contacting sections of the electrically conducting first pattern with an array of spaced apart contact elements.