Sang Hoon Lee
Ph.D. student, Konkuk University
Development of Roll-to-Roll Printed Electronics Technology for Air-Gap Touch Sensors
Recently, many studies have been conducted to employ printed electronics techniques for fabrication of flexible electronic devices. Printed electronic devices include OTFT, OLED, OPV, and sensors. Air-gap structure is needed for many types of sensors, such as touch sensors, accelerometers, and gyro sensors. Since printed electronics process includes printing and curing only, it is difficult to fabricate air-gap devices using printed electronics techniques. In this study, we propose a method for fabricating air-gap capacitive touch sensors using roll-to-roll printed electronics process which has the highest productivity . The schematic of air-gap capacitive touch sensor is shown in Fig. 1. First, silver ink was roll-to-roll slot-die coated to form the bottom electrode (the first layer). Barium Titanate (BaTiO 3 ) was roll-to-roll slot-die coated to form the dielectric layer (the second layer). Then, the sacrificial layer (the third layer) was formed by roll-to- roll slot-die coating of Polyvinyl Alcohol (PVA). Cured PVA is soluble in water. The top electrode (the fourth layer) was formed on the sacrificial layer by roll-to-roll gravure printing of stretchable silver ink. On the top electrode, epoxy resin was spin-coated to form the structural layer (the fifth layer). Then the sample was put in water for one hour to remove the sacrificial layer and to form an air-gap. All layers of the sample except the structural layer were cured in an infrared oven. The structural layer was cured in a hot-air oven. Materials and fabrication methods for each layer of the air-gap touch sensor sample are described in Table I.
Sang Hoon Lee received his M.S. degree in Mechanical Design and Production Engineering in 2015 from Konkuk University, Seoul, Korea, where he is currently pusing his Ph.D. degree. His research interests include printed electronics, flexible electronic devices, air-gap devices, and roll-to-roll printing processes.
Konkuk University, located in Seoul, Korea, is a highly reputed private university that is committed to research.
Konkuk University aims at fostering intellectuals with well-rounded character, future-oriented professionals, and leaders of community development, based on the virtues of sincerity, fidelity, and righteousness.