MEMS Electrostatic Double T-Shaped Spring Mechanism for Circumferential Scanning

A novel microelectromechanical systems (MEMS)-based microscanner is developed with the ultimate goal of integrating it into an endoscopic probe for use in clinical investigations. Microassembly technology is utilized to construct this device, which consists of an electrostatic-based microactuator and a pyramidal polygonal microreflector. A two-stage double T-shaped spring beam system is introduced to the actuator for displacement amplification as well as for motion transfer from the translational movement of the in-plane comb drives to the rotation of the central ring-shaped holder. In the meantime, an eight-slanted-facet-highly-reflective pyramidal polygonal microreflector is developed using high-precision diamond turning and soft lithography technologies. This reflector design requires only a small mechanical rotational angle to achieve full circumferential scanning. This MEMS device is developed with the goal of integrating it into an optical coherence tomography probe that could provide an alternative for endoscopic optical coherence tomography applications that would have the advantages of circumferential imaging capability, fast scanning speed, and low operational power consumption.