(designed and manufactured by KAIST/SEIL)
Wearable non-invasive continuous psychological stress sensing and evaluation technology is composed of novel wearable non-disruptive multi-channel Human sensor pads and criteria evaluators using advanced mathematical tools including Artificial Intelligence, and AI/cloud-based diagnosis, feedback and management protocols.
The proposed technology forms a category that we call “analytical wearables”. This is a category aimed at “professional controlled environments”. It is characterized by a synergy between high-tech sensing and high-level mathematical analysis providing compound interpretations of various sensor-based observables.
A human monitoring patch integrates four sensors of skin temperature, skin conductance, pulsewave and blood oxygenation in the size of stamp (25 mm × 15 mm × 72 microns) in order to enhance wearing comfort with small skin contact area and high flexibility. The skin contact area is minimized through the invention of an integrated multi-layer structure and the associated microfabrication process. Thus it is reduced to 1/125 of that of the conventional single-layer multiple sensors. The patch flexibility is increased mainly by the development of flexible pulsewave sensor, made of a flexible piezoelectric membrane supported by a perforated polyimide membrane.
The band enhanced wearing comfort can be used. The novelty of the present patch is its compact size and high flexibility; thereby, easily built into the commercial wearables. The present patch has applications for not only patients but also non-patients by monitoring autonomous nervous system (ANS). For patients, the present patch can alert or notice the potential risks related to the ANS for doctors to monitor medical patients, using communication modules of the wearable devices. The present patch can also alert rescue teams of emergency situations such as during a heart attack.
The stress monitoring patch consists of three layers: a skin contact layer,
an insulation layer, and a pulsewave sensing layer. The skin contact layer, making direct skin contacts, contains
the skin temperature sensor and skin conductance sensor both using aluminum electrodes. The insulation layer
of parylene-C provides the electrical isolation between the skin contact layer and the pulsewave sensing layer.
In the pulsewave sensing layer, the silver electrode is sandwiched between the piezoelectric membrane and the
polyimide support membrane with windows.
Dimensions and performance of the patch are design to detect the Human physiological signals, including
skin temperature, skin conductance and pulsewave. The human peripheral skin temperature and skin conductance
are changed in the range of 30–40°C and 2–20 μS, respectively. Human pulsewave is strongly depending
on the Human states, such that the systolic-diastolic pressure difference is varying in the range of 40–120 mmHg
at the frequency of 50–200 BPM (0.83–3.66 Hz) between Human resting state and exercising state.