Research On Driving And Control Of MEMS 2-D Scanning Micromirror Based On Ring-Down Method

MEMS(Micro-Electro-Mechanical System)2-D scanning micromirror is the core component of the new generation of three-dimensional imaging lidar,which has the advantages of high resolution,fast imaging speed,small volume,low price and safety for human eyes.In practical application,electromagnetic MEMS scanning micromirror is greatly affected by temperature,and its mechanical properties and stress state change.In addition,high temperature and low temperature will lead to a highly nonlinear relationship between applied voltage and tilt angle,which may lead to distortion of imaging applications and large loss of optical switches.Therefore,it is very important to study the influence of temperature on the MEMS 2-D scanning micromirror and its compensation,which provides technical support for its application in lidar and other devices.In this paper,the driving and control methods of the electromagnetic MEMS 2-D scanning micromirror are studied.Based on the study of the mechanism of the electromagnetic MEMS2-D scanning micromirror,the structure analysis and preparation technology of the electromagnetic MEMS 2-D scanning micromirror are studied,and the dynamic model of the equivalent resonator is established.On this basis,the measurement and control circuit of electromagnetic MEMS 2-D scanning micromirror is analyzed and designed in detail,focusing on the design of the closed-loop phase-locked driving circuit.The self-excited closed-loop drive circuit and the phase-locked loop circuit are used to drive and control the electromagnetic MEMS 2-D scanning micromirror from the aspects of amplitude control and phase control respectively.In order to solve the problem that the output changes with the temperature,the detection circuit based on the Ring-Down method is developed,and the Q-value detection circuit based on the Ring-Down method is designed to realize the temperature compensation of the output of the MEMS 2-D scanning micromirror at full temperature.On this basis,the design and performance test of the drive and control circuit of MEMS 2-D scanning micromirror based on Ring-Down method are completed.When the driving voltage is 0.2V,the optical angle of the fast axis and the slow axis can reach 42.48° and 11.80°respectively.In the temperature range of-20? to 40?,through the compensation based on Ring-Down method,the amplitude temperature coefficient TCA of MEMS 2-D scanning micromirror is increased from-0.209%/?to-0.072%/?,which verifies the function of closed-loop phase-locked driving circuit to achieve amplitude stabilization output and the feasibility of Ring-Down circuit to achieve temperature compensation.