Ultrathin Conformable Electronic Tattoo for Tactile Sensations

Abstract Conformable electronics has emerged in recent years as an innovative research field and the ability of conformable devices to monitor human physiological signals has been extensively explored. Therefore, in this study, the possibility of using conformable electronics as active devices capable of providing stimuli to the human body is investigated. In particular, a new approach is proposed to elicit tactile sensations on human skin using an operating principle based on the generation of localized heat in correspondence with a closed volume of air. This latter consequently expands causing the deformation of a thin membrane. The use of fast prototyping fabrication techniques, i.e., inkjet printing, and commercially available materials, i.e., transfer tattoo paper, allow the device to be produced quickly and easily transferred on the target substrate. Despite the ultrathin thickness (few micrometers), it is possible to observe forces and displacements thanks to localized heating at very low working powers (<300 mW). A pilot test on a voluntary subject demonstrates how it is possible to discriminate the tactile sensation elicited by the active tattoo device. While the working principle on a single taxel is demonstrated, these results show the potential of the new approach for developing wearable tactile displays.