KAIST Professor Joonbo Yoon’s research team has developed a pressure sensor capable of detecting pressure at high resolution even when wet. Recent advancements in robotics have allowed robots to handle delicate tasks, such as picking up an egg without breaking it, thanks to pressure sensors integrated into the robot’s fingertips that provide precise tactile information.
KAIST announced on the 10th that Professor Yoon’s team in the Department of Electrical and Electronic Engineering has developed a pressure sensor that can detect pressure with high resolution without being affected by external interferences like “ghost touches” which occur when water droplets disrupt the smartphone’s touch sensitivity during rain or after a shower.
The commonly used capacitive pressure sensors in smartphone touch systems have simple structures and excellent durability, making them ideal for human-machine interfaces in devices like smartphones, wearables, and robots. However, they are prone to malfunction due to external interferences, such as water droplets, electromagnetic disturbances, and bends, due to the “fringe field” occurring at the sensor’s edges being extremely susceptible to such disturbances. To address this, the research team aimed to suppress the fringe field causing these issues.
The researchers focused on the structural variables affecting the fringe field through theoretical approaches and found that narrowing the electrode gap to a few hundred nanometers can reduce the fringe field occurrence to below a few percent. Subsequently, they developed a nanogap pressure sensor using proprietary micro-nano processing technologies with an electrode gap of 900 nanometers. The developed sensor reliably detected pressure regardless of the material applying it, and its performance was verified to be unaffected by bending or electromagnetic interference.
Additionally, the team harnessed the sensor’s properties to implement an artificial tactile system. The human skin contains Merkel’s discs, pressure receptors that sense pressure. The team succeeded in creating an artificial tactile system that only responds to pressure and not to external interferences, achieving a density comparable to Merkel’s discs. They also designed a force touch pad system capable of producing high-resolution outputs for various electronic applications.
Professor Yoon stated, “The ‘nano-gap pressure sensor’ performs stably without malfunctioning in conditions like rain or sweating, unlike conventional pressure sensors. We expect it will alleviate the inconveniences many face in daily life.” He also noted that it could drive revolutionary changes in diverse fields such as precision tactile sensors for robots, medical wearables, and interfaces for augmented reality (AR) and virtual reality (VR).
The study was conducted by Dr. Jaesoon Yang, Ph.D. candidate Myunggeun Jeong from KAIST Electrical and Electronic Engineering, and Professor Jaeyoung Yoo from Sungkyunkwan University’s Department of Semiconductor Systems Engineering (a KAIST Ph.D. graduate), and was published in the renowned international journal “Nature Communications” on the 27th of last month.
This research was supported by the National Research Foundation of Korea’s Mid-career Researcher Support Program and the Leading Research Center Support Program.