Revolutionizing Medical Imaging With Micromirror Technology
ECE Assistant Professor Benyamin Davaji, in collaboration with Shahrzad Towfighian from SUNY at Binghamton, was awarded a $550,000 NSF grant for “Merging Electrostatic and Ferroelectric MEMS Actuators To Create Tunable High-Speed Scanners.”
This collaborative research focuses on developing a novel scanning micromirror based on scalable MEMS technology. Merging electrostatic actuation with ferroelectric polarization switching in this project enables a large dynamic scan range with nonvolatile tunability for micromirrors. The programable MEMS scan engine developed under this project will be used for microendoscopic imaging, integration into surgical tools, addible integrated smart pill microsystems, and projection patterning light engines.
Davaji is one of the core faculty of the Institute for NanoSystems Innovation (NanoSI) and runs the Autonomous Integrated Microsystems (AIMS) laboratory.
Abstract Source: NSF
This project aims to create micro-mirrors for applications in endoscopes that enable controlling the depth-of-focus and imaging in real-time. These instruments can guide surgeries to distinguish normal and malignant tissues with sub-cellular resolution. State-of-the-art endomicroscopy utilizes MEMS scanning mirrors for single-axis and dual-axis confocal microscopy. However, the depth of focus and scanning speed are severely limited because of the actuation mechanism. The most common actuators have been based on conventional electrostatic mechanisms that face two bottlenecks: small range of motion and limited speed. The team of investigators will overcome those limitations by using electrostatic levitation that enables large strokes away from the substrate. To enable high-speed scanning, investigators will adopt ferroelectric material to control spring stiffnesses. This property enables achieving a wide range of scanning speeds at any elevation. The large range of motion because of electrostatic levitation, and stiffness tunability using ferroelectric material will permit the development of tunable MEMS scanners that can revolutionize endomicroscopy for real-time in vivo imaging and 3D depth sensing. The new microscanner increases the depth of focus and enables deep tissue penetration over a large FOV with sub-cellular resolution. To educate a wide range of learners, the investigators develop workshops for demonstrating the basics of micromirrors and present them to elementary schools as well as undergraduate students. Investigators will involve undergraduate students from a diverse group of students, including underrepresented minorities.
This project will create new knowledge on the interaction of electrostatic levitation with ferroelectric polarization switching. Based on this new knowledge, investigators will create tunable high-speed and large-stroke MEMS mirrors. For more than forty years, MEMS mirrors for imaging applications have been based on conventional gap-closing mechanisms that severely suffer from a limited range of motion and pull-in instability. To address those issues, a team of researchers will introduce electrostatic levitation electrodes that allow the actuator to move away from the substrate and have its motion become a linear function of applied voltage. To achieve tunable high-speed actuation, the team will incorporate springs made of integrated ferroelectric material that enables stiffness tuning to trigger modes of interest, e.g., titling or out-of-plane at desired frequencies. The merger of electrostatic levitation and ferroelectric polarization switching creates challenging behaviors that have prevented researchers from adopting it for micro-mirror applications. Investigators will present a computational, analytical, and experimental platform to present a fundamental understating of the underlying multiphysics of the system. In addition, the team will create a MEMS mirror that achieves high-speed large strokes and rotations from four actuators on its periphery. The micromirror prototype will pave the way for its future application in real-time in vivo microendoscopy.