Printed Skin-Compatible Electrodes With Ionic Adhesive Interface
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Solution Overview
Problem
Existing bio potential electrodes dry out over time, cause skin irritation, and are not suitable for prolonged measurements due to high salt and water content, leading to signal degradation and poor adhesion.
Innovation Solution
A method involving printing a conductive ink on a flexible substrate to form an electrically conductive layer, followed by coating an adhesive interface layer with an ionically conductive pressure-sensitive adhesive composition, which includes a resin and ionic liquid, to create a skin-compatible electrode with low impedance and stretchability, allowing for prolonged use without skin irritation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrodes are used, then electrical contact is achieved, but skin irritation and discomfort occur due to adhesives and harsh cleaning requirements
Solution Approach 1:
The patent removes harmful adhesives and conductive gels from the electrode structure entirely. The electrode utilizes the intrinsic conductivity of conductive thread or fabric combined with the body's natural skin conductivity, eliminating substances that cause skin irritation while maintaining reliable electrical contact.
Solution Approach 2:
The electrode is designed as a disposable, single-use component that can be applied and removed without damaging the skin. This approach prioritizes skin health over reusability, allowing the electrode to be discarded after one use while preventing cumulative skin irritation from repeated adhesive application and removal.
2Stability of the object's composition
If conventional electrodes with adhesives are used, then electrode stability is achieved, but skin damage occurs upon removal
Solution Approach 1:
Adhesives are completely removed from the electrode design. Instead of using adhesive-backed materials, the electrode relies on mechanical attachment methods such as elastic bands, clips, or self-adhering non-irritating materials that can be removed without pulling or damaging the skin.
Solution Approach 2:
The electrode employs flexible, thin conductive materials that conform to the skin surface and can be easily applied and removed without causing mechanical stress or damage to the skin, maintaining stability during use while ensuring safe removal.
3Reliability
If conductive gels are used, then electrical conductivity is improved, but bacterial growth and skin irritation are promoted
Solution Approach 1:
Conductive gels are completely eliminated from the electrode system. The patent achieves electrical conductivity through conductive threads or fabrics in direct contact with the skin, utilizing the body's natural skin conductivity without requiring external conductive media that can harbor bacteria.
Solution Approach 2:
The electrode system uses the body's own skin conductivity as the conductive medium, eliminating the need for external conductive gels or pastes. This self-service approach leverages the natural properties of human skin to provide the necessary electrical conductivity without introducing harmful substances.
4Reliability
If harsh cleaning is performed to remove conductive gel, then electrode function is maintained, but skin drying and irritation occur
Solution Approach 1:
Conductive gels that require harsh cleaning are completely removed from the electrode design. The electrode maintains its function through conductive materials in direct contact with the skin, eliminating the need for gel removal and associated skin drying effects.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3C
AI summary
A method of manufacturing a skin-compatible electrode (100) comprises printing a circuit pattern (P1) onto a flexible substrate (200) to form an electrically conductive pattern including an electrode pad area (301). A layer of an adhesive composition (401p) is printed in a second pattern (P2) onto the electrode pad area (301) to form an adhesive interface layer (401). The adhesive interface layer (401) is a dry film formed from the adhesive composition (401p) comprising an ionically conductive pressure sensitive adhesive composition comprising a resin (R), an ionic liquid (I), and optionally electrically conductive particles (P). A layer thickness and material of the flexible substrate, the conductive pattern, and the conductive adhesive interface have relatively low stiffness in plane of the flexible substrate (200).