Investigation Of The Thermal Behavior Of An Electrothermal Folded Dual S-shaped Micromirror

Micro-Opto-Electro-Mechanical System is the combination of optics and Micro-Electro-Mechanical System,which has superior advantages such as lost cost,high performance,microminiaturization,easy integration and high reliability.As a significant component of the Micro-Opto-Electro-Mechanical System,electrothermal micromirror has become a hot issue.However,investitations of thermal behavior of the micromirror are still inadequate,especially the thermal behavior during dynamic actuation.This thesis mainly investigates the thermal behavior of an electrothermal folded dual S-shaped micromirror with tip-tilt-piston capability,low driven voltage,large piston displacement,simple process flow.Firstly,we investigate the heat transfer process of micromirror by experimental method.The temperature oscillations of the micromirror is achieved by measuring the change of the resistance of the embedded Ti heater,due to the temperature dependence of heater resistance.Moreover,optical measurement system and vacuum measurement system are established,with which we could obtain the temperature oscillations of the micromirror under various inputs and environment,giving aid to analyzing the heat transfer process.We finally prove that convection is feeble in microscale and heat conduction should dominant the heat transfer process with the air.In addition,according to the previous conclusion obtained by experiment,a simple,fast,low-cost thermal equivalent circuit model is established by discereting the heat equation,through which we have evaluated the effective heat transfer coefficient is about 2282 W/m~2K.At last,a finite element model is established using the FE software ANSYS to verify the results acquired previously,and the thermal equivalent circuit model turns out to be accurate and valid.