Real-Time Monitoring of Haptic Response Using Ultra-Thin SI/PZT Stacked Sensors and Actuators in Soft Flexible Packaging for Wearable and Medical Applications

This paper presents the development and evaluation of stacked ultra-thin haptic sensors and actuators designed for wearable and medical applications. As an example, we demonstrate the device's performance while operating under a strong magnetic field. This specific evaluation is part of a broader ongoing research project aimed at using functional Magnetic Resonance Imaging (fMRI) for brain analysis while participants undergo haptic stimulation with ultra-thin Si/PZT haptic actuators. Nevertheless, the demonstrated stacked construction, incorporating both a sensor and an actuator, shows potential for more common wearable applications in sports and entertainment by providing real-time dynamic haptic feedback based on sensor responses. Compared to commercially available haptic devices, the demonstrated stacked sensor and actuator, including the packaging, is extremely thin (under 300 μm), lightweight, and flexible. The flexible construction with soft packaging is suitable for bonding the devices to the human body. To assess the suitability of the actuators for applications involving fMRI, the actuators were subjected to strong magnetic fields. It was demonstrated that the actuators can operate effectively in magnetic fields up to 9T, which is an important feature for the specific medical applications explored in the scope of this study.