Domestic researchers developed a sensor that operates stably without external interference, even in environments like a water-dampened smartphone screen, and can detect pressure close to human tactile levels.
Professor Yoon Jun-bo and his research team from Korea Advanced Institute of Science and Technology (KAIST) announced on the 10th that they developed a sensor that can detect pressure with high resolution without being affected by the 'ghost touch' phenomenon, which causes incorrect recognition of touches when water is on the smartphone screen due to rain or after a shower. Their research results were published in the international journal 'Nature Communications' on Feb. 27.
Currently, the mainly used pressure sensor in touch systems is the 'capacitive method,' which recognizes objects by using electric fields. This sensor is simple in structure and highly durable, utilized in technologies for human-machine interfaces (Human-Machine Interface) such as smartphones, wearable devices, and robots. However, there was an issue of malfunction caused by external interference elements like droplets, electromagnetic interference, and bending due to curvature.
The research team identified the cause of interference occurring in capacitive method pressure sensors. They found that the 'fringe field' emanating from the edges of the sensor's electric field is extremely vulnerable to external interference.
The research team concluded that they must suppress the fringe field, which is the cause of the problem, and focused on exploring structural variables that affect the fringe field through a theoretical approach. Based on this, they were able to suppress the fringe field generated by the sensor to below a few percent by narrowing the electrode gap to a few hundred nm (nanometers, 1 billionth of a meter).
The research team developed a nano gap pressure sensor with a designed electrode gap of around 900 nm using their proprietary micro and NANO structural process technology. The developed sensor reliably detected only pressure, regardless of the material applying pressure, and was unaffected by bending or electromagnetic interference.
Additionally, the research team implemented an artificial tactile system utilizing the characteristics of the developed sensor. Human skin has pressure receptors called 'Merkel's disc' for detecting pressure, and to mimic this, a pressure sensor technology that reacts only to pressure without responding to external interference was necessary. While existing technologies had difficulty meeting these conditions, the sensor developed by the research team has overcome all these limitations and achieved a density comparable to Merkel's disc, enabling the implementation of an artificial tactile system capable of precise pressure detection wirelessly.
Professor Yoon Jun-bo said, "The nano gap pressure sensor developed this time operates stably without malfunctioning like existing pressure sensors in situations of rain or sweating, so it is expected to alleviate inconveniences many people have experienced in daily life," adding, "In the future, it could bring innovative changes in various applications such as precise tactile sensors for robots, medical wearable devices, and augmented reality (AR) and virtual reality (VR) interfaces."
References
Nature Communications (2025), DOI: https://doi.org/10.1038/s41467-025-57232-8