Low-power multi-scan patterns capable 3D-constructed piezoelectric MEMS mirrors

Abstract

This paper presents the feasibility of implementing various scan patterns, ranging from quasi-static to resonant driving methods, using newly developed 3D-constructed Al(Sc)N piezoelectric MEMS mirrors. A description of the assembled device and how each driving method was tried and characterized are also provided. According to the quasi-static driving test result, tilting angle of ±10° was achieved by both AlN and AlScN based-MEMS mirrors. For 1D resonant scanning, total optical scan angle (TOSA) of 20° was obtained under the low applied voltage of 1.5 Vpp. Further investigations were conducted on various 2D scan patterns, including Lissajous and circular scans. The characterization results show that Lissajous scan patterns with various field-of-view (FOV) sizes can be realized by adjusting the applied voltage and driving frequencies. In the case of circular scan, a TOSA of 10° was achieved, demonstrating the potential for 360° of omnidirectional scanning using the presented mirror devices. In addition, assessments of the electrical stability of fabricated piezoelectric material under high voltage and the mechanical robustness based on long-term cycling tests were conducted to ensure the reliability of the device. The presented low-power compact Al(Sc)N-based piezoelectric MEMS mirror device possesses a wide range of specifications, affording it the capability for application and customization to meet various purposes, while also holding significant potential for further advancements in its utility.