A Breakthrough in Stretchable Display and Sensor Technologies
Samsung Electronics announced on June 4 that researchers at the Samsung Advanced Institute of Technology (SAIT), Samsung’s R&D hub dedicated to cutting-edge future technologies, published research in the world-renowned journal ‘Science Advances’ about a technology that overcomes the limitations of stretchable devices.
A stretchable device requires a stretchable display that can be stretched in all directions like rubber bands to change their shapes. A stretchable display is a core technology for free-form displays.
The company said this study has achieved a stable performance in a stretchable device with high elongation. This research was also the first in the industry to prove the commercialization potential of stretchable devices, given that the technology is capable of being integrated with existing semiconductor processes.
The SAIT research team was able to integrate a stretchable organic LED (OLED) display and a photoplethysmography (PPG) sensor in a single device to measure and display the user’s heart rate in real-time, thus creating the ‘stretchable electronic skin’ form factor. The success of this test case proves the feasibility of expanding the technology to further applications. This research is expected to increase the uptake of stretchable devices in the future.
One of the biggest achievements of this research was that the team was able to modify the composition and structure of ‘elastomer,’ a polymer compound with excellent elasticity and resilience, and use existing semiconductor manufacturing processes to apply it to the substrates of stretchable OLED displays and optical blood flow sensors for the first time in the industry. The team were then able to confirm that the sensor and display continued to operate normally and did not exhibit any performance degradation with elongation of up to 30 percent.
To put their research to the test, the SAIT researchers attached stretchable PPG heart rate sensors and OLED display systems to the inner wrist near the radial artery. Doing this allowed them to confirm that wrist movement did not cause any property deterioration, with the solution remaining reliable with skin elongation of up to 30 percent. This test also confirmed that the sensor and OLED display continued to work stably even after being stretched 1,000 times. What’s more, when measuring signals from a moving wrist, the sensor was found to pick up a heartbeat signal that was 2.4 times stronger than would be picked up by a fixed silicon sensor.
“The strength of this technology is that it allows you to measure your biometric data for a longer period without having to remove the solution when you sleep or exercise, since the patch feels like part of your skin. You can also check your biometric data right away on the screen without having to transfer it to an external device,” explained principal researcher Yun Young-jun, corresponding author of the paper. “The technology can also be expanded to use in wearable healthcare products for adults, children and infants, as well as patients with certain diseases.”