The prototype described in a presentation titled "Continuous health-monitoring with ultraflexible on-skin sensors" consists of gold nanomesh-based breathable skin sensors and an elastic display that fits snugly on the skin, so recorded data (such as an electrocardiogram or temperature) can be made readily visible for the patient. Combined with a wireless communication module, this integrated biomedical sensor system could transmit biometric data to the cloud for physicians to monitor.
The skin display, developed in cooperation with Dai Nippon Printing (DNP) consists of a 16x24 array of red microLEDs (1×0.5mm in size) and screen-printed stretchable silver wiring mounted onto a rubber sheet. Only 1mm thick, it can be stretched to 45% of its original size, taking its 16×24 pixels from a 38×58mm2 effective display area to 64×96mm2 when stretched, with pixel pitch increasing from 2.4mm when contracted to a maximum of 4.0mm when extended.
The stretchable display is addressed at 2V by a passive matrix and can be refreshed at 60Hz, fast enough for any biomedical data or to run small messaging animations that compassionate relatives may want to send to the patient.
Someya was keen to highlight that the new display was far more resistant to the wear and tear of stretching than previously reported wearable displays.
"It is built on a novel structure that minimizes the stress resulting from stretching on the juncture of hard materials, such as the micro LEDs, and soft materials, like the elastic wiring—a leading cause of damage for other models", he says.
During stretching tests, and while being worn on a contracting hand, not a single pixel failed. As for the nanomesh skin sensors (see Gold nanomesh enables ultra-breathable skin electronics), because they are breathable, they can be worn on the skin continuously for a week without causing any inflammation. With their gold-nanomesh skin electronics, the researchers were able to sense temperature, pressure, myoelectricity and even record an electrocardiogram.