【作者】 李元元；

【导师】 陈维友；

【作者基本信息】 吉林大学 ， 微电子学与固体电子学， 2007， 硕士

【摘要】 在深入分析各种电容式微加速度传感器的工作原理的基础上,本论文决定以变面积差分电容式结构作为设计和分析对象。根据支撑梁结构和数量的不同,提出双折叠梁和四折叠梁两种设计方案。接着利用材料力学相关知识为理论计算提出合理性假设和简化,然后推导了质量块在加速度下的位移量Δl、电容变化ΔC和弹簧有效刚度的公式,分别得到了它们与微结构各项参数的关系,并对折叠弹簧梁进行了失效分析,讨论了折叠梁有效工作范围。进一步分析并研究了微结构所依赖的各项结构性能指标,同时提出了理论优化方案。最后利用有限元分析软件ANSYS分别对双折叠梁和四折叠梁结构进行实体建模仿真。并单独对折叠梁进行了结构静力分析,讨论了它的抗过载情况。另外,通过改变折叠梁和质量块的厚度,弹簧的横向宽度等各项结构尺寸分析了这两种结构各阶的模态振型以及在加速度下质量块位移和折叠梁的应力分布。经过模拟分析,在尽可能保证各项性能指标最优化的前提下决定选用四梁结构。进一步优化其参数尺寸,并对该四梁结构进行了谐响应分析,得到工作频率和最大位移的线性关系。更多还原

【Abstract】 Silicon capacitive accelerometer is an example of the most rapidly and successfully development in the field of MEMS (Micro Electro Mechanical System) .MEMS is notjust the miniaturization of the traditional machines, new analysis and design methods need to be developed to meet the further development because of the size and surface effects encountered in micro systems.The modeling and simulation of MEMS then play an important role in this field because these techniques are very important for improving its performance, shortening its development period and lowing its cost. The capacitive accelerometer is one of the typical MEMS products.The research on its modeling,simulation and optimization is of great referential value for exploring the technolo- gy of the modeling and simulation MEMS.This theis first states the category,background and present situation,then introduce several typical micromachined capacitive accelerometer designed in recent years and analyze them in detail respectively.Based on the operating and mechanical principle of capacitive accelerometer,we designed a kind of Variable-area differential capacitive accelerometer with folding rectangle-spring beam. The structure of its sensitive element is composed by Spring-Mass-Spring, belong to the second-order vibration system. Further, the formula of mass displacement under accelerometer, variation of capacitance and the effective rigidity of folding spring are deduced by utilizing knowledge of material mechanics. From these formula, we get the relationship among structural parameters. In addition,this theis study the effective operating range of folding spring through its analysis of inactivation. The performance index such as natural frequency, sensitivity, measurement range damping,distinguishability are also discussed. Furthermore,the method of theory optimization is put forward,acted as a theoretical basis for the modeling and simulation.Applied with ANSYS, a software of finite element,we designed double spring and four spring structure,their first four modals of micro structure are obtained through changing the size of spring and mass. Besides displacement and modal of mass, we also studied the distribution of stress on folding spring. After the analysis of statics and transient dynamics and compared the results of two structure, we decided to adopt four folding spring structure. Further, we also got the optimally size of sensitive chip.更多还原