MEMS面内电热微驱动器中U型梁的分析

Analysis of U Type Beam in MEMS In-plane Electro Thermal Actuator

介绍了一种单刀双掷面内电热微驱动器。基于U型梁受热膨胀的原理,在电压作用下梁受热变形,推动接触电极和信号电极接触,进而输出信号。分别采用金属镍和氮化硅作为驱动器主体结构和隔离部分的结构材料。利用Coventorware软件对驱动器中U型折叠梁进行有限元仿真,得出折叠梁在温度为300 K、电压为3 V、热臂宽度为2μm时,冷臂宽度和驱动位移、驱动力之间的曲线关系图,进而确定冷臂的宽度为20μm。此时梁的位移为22μm,固定端受力为180 N。最后进行应力校核,梁的最大应力为120 MPa,小于镍的许用应力,具有较高的可靠性。

This paper presented a kind of single pole double throw（ SPDT） micro electro thermal actuator,which was inplaned. It worked based on the U type beam heated expansion principle,making the beam thermal deformation under the effect of voltage and promoting the contact electrode contacted with the signal electrode,then output the signal. The actuator used nickel as the main structure material,and silicon nitride as the isolating material. Finite element simulation of the U type folded beam of the actuator was done using the Coventorware software. The relationship between the cold arm width and the driving force and the displacement curve diagrams was got when the temperature was 300 K,voltage was 3 V and the hot arm width was 2 μm,then that the cold arm width was 20 μm was determined. In that condition,the beam displacement was 22 μm and the fixed end force was 180 N. Finally,through checking the stress,the result shows that the maximum beam stress is 120 MPa,which is smaller than the allowable stress of nickel,showing that the U type folded beam has high reliability.