Moistened Sensor Contact Unit for Continuous ECG Monitoring
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Solution Overview
Problem
Existing ECG measurement technologies face limitations in long-term use due to electrode dry-out, movement artifacts, and the need for skin moisture, making them unsuitable for continuous monitoring, especially in dry skin conditions and for extended periods.
Innovation Solution
A sensor contact unit with a textile layer, a planar moistening element, and a liquid reservoir that uses defined vapor delivery to maintain skin moisture without chemical additives, featuring a water vapor-permeable yet waterproof design to ensure continuous electrical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gel electrodes are used for ECG measurement, then measurement reliability is improved, but duration of action is limited to approximately 24 hours due to drying out
Solution Approach 1:
The electrode system is divided into separate functional layers: a textile layer with conductive elements, a moistening element with inner and outer layers, and a liquid reservoir. This segmentation allows independent optimization of each component, particularly enabling the liquid reservoir to continuously supply moisture to the inner layer, thereby maintaining measurement reliability over extended periods without the entire electrode needing replacement after 24 hours.
Solution Approach 2:
The liquid reservoir is pre-filled with liquid before use, and the moistening element is pre-positioned between the textile layer and skin contact surface. This preliminary preparation ensures that moisture is immediately available upon application, eliminating the need for gel application procedures and enabling continuous operation beyond the 24-hour limitation of conventional gel electrodes.
2Duration of action of moving object
If dry electrodes are used to extend duration of action, then duration of action is improved, but measurement precision deteriorates due to movement artifacts and high skin pressure requirements
Solution Approach 1:
The moistening element acts as an intermediary layer between the dry textile electrode and the skin. It maintains optimal moisture levels at the skin interface, ensuring good electrical contact and signal quality without requiring excessive pressure. This mediator layer allows the electrode to function effectively during physical activity and perspiration while maintaining measurement precision, overcoming the movement artifact problems of conventional dry electrodes.
3Duration of action of moving object
If dry electrodes are used for long-term measurement, then duration of action is improved, but device complexity increases due to inability to function on dry skin
Solution Approach 1:
The electrode system is designed to function universally across different skin conditions (dry, moist, perspiring) and activity levels. The liquid reservoir and moistening element combination enables the electrode to adapt to varying moisture requirements, making it suitable for both stationary long-term monitoring and dynamic physical activity scenarios, thereby achieving versatility across multiple application contexts.
4Reliability
If chemical additives are used in electrode systems, then measurement reliability is improved, but loss of substance occurs due to evaporation and chemical depletion
Solution Approach 1:
The system design allows for recovery and reuse. The liquid reservoir can be refilled with fresh liquid, and the textile layer with conductive elements can be reused. Only the consumable liquid is replaced, not the entire electrode system. This recovering approach significantly reduces waste compared to disposable gel electrodes that must be discarded after 24 hours, addressing both reliability and substance loss concerns.
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
Enables long-term, reliable ECG measurements independent of skin moisture levels and reduces movement artifacts, allowing for continuous use without the need for gel or chemical additives.
Implementation Method 1
The inner layer ( 14) is formed from a material which is permeable to water vapor
Implementation Method 2
the invention is thus suitable, due to the choice of materials and the design, to make advantageous use of the aggregate states, namely the slow and defined release of water vapour
Data Source
Figure 1
Figure 2
AI summary
To improve a sensor contact unit (2) for measuring electrical signals of a body, a sensor contact unit of this kind is proposed with a first textile layer (4), in or on which electrically conductive filaments are arranged, with a planar moistening element (10), which rests on the textile layer, with an electrical connection (34), which is in electrical contact with the textile layer (4), and with a liquid reservoir (26). The planar moistening element (10) comprises an inner layer (14) resting on the textile layer (4), an outer layer (16), and, arranged between these, a moistening area (18). The inner layer (14) is made of a material that is permeable to water vapor but is watertight, and the moistening area (18) can be brought into contact with the liquid reservoir (26) in order to feed the moistening area (18).