Design of PMN-PT single crystal ultrasound transducer and mid-air haptic feedback control

Abstract

This thesis explores the advancement of ultrasound transducer technology for mid-air haptic applications, specifically addressing the limitations of current commercial transducers. The research is motivated by the growing demand for enhanced interactive experiences in virtual and augmented reality, requiring improvements in haptic feedback devices' focal point accuracy and reduction of side lobes. A key aspect of the research involved the design and fabrication of compact transducers, utilizing innovative MEMS technology alongside piezoelectric materials and a silicon passive layer. This approach aimed to optimize crucial parameters such as radiation efficiency, resonance frequency, and PMN-PT single crystal size. The resulting transducers, significantly thinner and smaller than conventional models, maintained performance levels that are competitive with existing solutions. Their uniform directivity was particularly notable, demonstrating their potential as effective alternatives in haptic technology. In addition, the study developed new control methodologies for the ultrasound transducer array, focusing on crosstalk issues and establishing the relationship between voltage input and velocity output. These advancements included innovative control strategies and a multi-channel phase control circuit, marking significant progress in ultrasound array control technology. The outcomes of this research highlight the significant potential of these new transducers and control methods in transforming haptic experiences in VR and AR settings, contributing valuably to the field of haptic technology and opening new directions for future research.