Printed Strain Sensor with Crack-Based Resistance for Sleep Monitoring
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Solution Overview
Problem
Current sleep monitoring technologies, such as wearable sensors and camera-based systems, are invasive, uncomfortable, and costly, lacking sensitivity and adaptability for large-scale manufacturing, which hinders accurate and widespread monitoring of sleep-related disorders.
Innovation Solution
A non-invasive strain sensor system integrated into a mattress, comprising a flexible and stretchable substrate with conductive inks and a hot-melt encapsulation layer, which detects physiological parameters like body movement and breathing by measuring changes in electrical resistance, and communicates these data wirelessly for analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wearable strain gauge sensors are used for monitoring, then measurement precision is improved, but ease of operation deteriorates due to discomfort and interference with sleep
Solution Approach 1:
The patent replaces mechanical wearable strain gauge sensors with a non-contact radar-based monitoring system. The radar system uses electromagnetic waves to detect chest and abdominal movements, eliminating the need for physical contact with the user's body. This substitution maintains measurement precision while completely removing the discomfort and sleep interference associated with wearable devices.
Solution Approach 2:
The patent introduces radar technology as an intermediary between the monitoring system and the user. Instead of direct mechanical contact through wearable sensors, the radar system acts as a mediator that captures physiological data through electromagnetic radiation, enabling accurate monitoring without physical intrusion into the user's sleep space.
2Ease of operation
If camera-based systems are used for non-wearable monitoring, then ease of operation is improved, but use of energy and cost increase making them impractical for everyday use
Solution Approach 1:
The patent extracts the essential monitoring function from complex, high-power camera systems and implements it through a simplified radar-based approach. By taking out only the necessary capability to detect chest and abdominal movements via electromagnetic waves, the system achieves non-wearable convenience while dramatically reducing energy consumption and cost.
Solution Approach 2:
The patent employs a cost-effective radar system that uses very low power consumption compared to camera-based solutions. The system is designed to be economically viable for everyday consumer use, eliminating the high operational costs associated with continuous camera operation while maintaining effective sleep monitoring capabilities.
3Use of energy by moving object
If piezoelectric sensors are used for non-wearable monitoring, then use of energy is reduced, but measurement precision deteriorates due to inability to recognize movement direction
Solution Approach 1:
The patent implements a radar-based system that provides multi-functional monitoring capabilities, including detection of movement direction, chest motion, abdominal motion, and respiratory rate. This universal approach maintains the low power consumption advantage of piezoelectric sensors while overcoming their limitation in movement direction recognition through the use of Doppler radar technology.
Solution Approach 2:
The patent changes the detection parameter from the electrical resistance changes used by piezoelectric sensors to electromagnetic wave frequency shifts (Doppler effect) used by radar. This parameter change enables the system to capture directional movement information and multiple physiological parameters simultaneously while maintaining very low power consumption levels.
4Ease of manufacture
If commercial piezoelectric sensor systems are deployed, then ease of manufacture is improved, but measurement precision and functionality are insufficient
Solution Approach 1:
The patent replaces commercial piezoelectric sensor systems with a radar-based monitoring solution that can be integrated into existing mattress structures. This substitution maintains ease of manufacture through standardized radar component integration while dramatically improving measurement precision, sensitivity, and functional capabilities including directional movement detection.
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 system provides a low-cost, reliable, and comfortable means to monitor sleep behavior and diagnose sleep-related disorders, offering improved sensitivity and scalability, reducing discomfort and production costs while enabling real-time data collection and analysis.
Implementation Method 1
sensing layer printed with a second conductive ink in direct contact with the electrode layer
Implementation Method 2
encapsulating the electrode and sensing layers by applying a hot-melt layer
Data Source
AI summary
The present disclosure generally relates to an electronic strain sensor, a system incorporating the sensor, and a method of manufacturing the sensor. The present disclosure also relates to methods of measuring one or more physiological parameters of a living subject, or methods of diagnosing a sleep-related disorder of a living subject, the methods comprising sensing a signal produced by the living subject with the electronic strain sensor or system. The strain sensor comprises: an electrode layer printed on a substrate, a sensing layer printed on a portion of the electrode layer, and an encapsulation layer encapsulating the electrode and sensing layers. The electrode layer exhibits a sheet resistance less than that of the sensing layer, and the sensing layer is in direct contact with the electrode layer. The sensor's electrical resistance can be increased through forming microscopic cracks in the sensing layer in response to forces applied to the sensor.