Destructive Reliability Analysis of Electromagnetic MEMS Micromirror Under Vibration Environment

Abstract

Micro-Electro-Mechanical Systems (MEMS) micro-mirrors have shown great potential in consumer applications, such as Light Detection and Ranging (LiDAR) devices and portable laser projectors. The LiDAR based on electromagnetic MEMS micro-mirror is usually exposed to vibration loads for autonomous vehicles, which results in the necessity for the destructive reliability assessment of micromirrors under vibration environment, but such studies are rarely reported. This paper explores the destructive reliability of electromagnetic MEMS micromirror under vibration environment according to the JESD22-B103B standard. The reliability evaluation is conducted by experimental tests, finite element stress analysis and theoretical dynamic response analysis. Micromirrors are tested under sweep excitation, and they are failed with the vibration level of around 33 g. The failure and stress analysis demonstrate that the crack fracture is located at the root of the slow axis. The nonlinear relationship between the peak displacement of the balance frame and acceleration levels is investigated through theoretical analysis. The nonlinearity of stiffness hardening is induced by the axial tensile strain of the beam, which contributes to the displacement-reduction of the gimbal. This work provides some valuable suggestions for the optimization design of MEMS micromirrors to improve the acceleration tolerance level in vibration environment.