When it comes to electronic skin sensors, the name of the game is stretchability. In recent years, researchers have developed a range of solutions for stretchable sensors and other electronics which, when integrated with a flexible substrate, adhere to and move with the skin like a band aid. Now, a research and development team at the Samsung Advanced Institute of Technology (SAIT) has developed an e-skin that has both a flexible optical blood flow sensor and a stretchable light display.
To create the new e-skin, the team first made chemical and structural modifications to a polymer compound to increase the substrate’s resistance to heat and damage caused by the sensor’s electronic components. Within this new substrate, the team nestled organic light-emitting diode (OLED) pixels between crevices in the tiny, grid-like structure of existing flexible sensor and semiconductor technology. The design allows the electronics and the substrate to stretch without affecting the pixels.
Using photoplethysmography (PPG) to detect changes in light during pulse phases, the new e-skin measures and displays heart rate in real time. According to the SAIT engineers, the technology remains functional when stretched up to 30% elongation. Furthermore, after 1,000 multidirectional stretches, both the sensor and the display continued to perform reliably. The SAIT engineers described their research in a paper published in the journal Science Advances earlier this month.
Although the current e-skin represents only the initial stages of development, Samsung, an early pioneer of the freeform optical display, believes the stretchy technology has enormous potential for consumers. When innovators have fully addressed issues of durability, comfort, and interface, flexible skin sensors will likely transform what we expect from wearable devices, both as personal health trackers and remote patient monitoring systems. Patients with severe chronic conditions will certainly benefit from a sensitive, accurate sensor with an integrated display: especially one that fits like a second skin.
