The Structure Analyses And Temperature Drift Compensation System Designs Of MEMS Pressure Sensors

Pressure sensors account for about one third of the total sensor market share,and their proportion continues to grow.Since pressure sensors are usually used to measure the pressure generated by fluid,their sensing chips are required to be directly exposed to the fluid.However,the pressure sensors are often worked in the fields with corrosive or poisonous environments in industry.In silicon oil pressure sensors,the pressure sensing chips are designed to be isolate-packaged with filled silicon oil to separate and protect the chips from the external media corrosion,and the environment pressure is transferred from the packaged components and silicon oil to the sensing chips for measurements.The corrugated diaphragms,as the core pressure sensing components for the package structures of the silicon oil pressure sensors,play the roles of pressure transfer.Theirs sensitivity and linearity properties will directly affect the measuring accuracy of the pressure sensors.In this work,the static and dynamic properties of corrugated diaphragms interested in the design of pressure sensors are studied with the Ansys finite element software.The static structure analyses including: to verify the validities of the numerical solutions,the comparisons of the central deflection under the uniform pressure and force between theories and Ansys are made at first.The effects on mechanical properties of the diaphragm structures with different corrugated shapes,thicknesses,wave heights and ripple numbers are then studied in detail with Ansys,which can provide references for the optimum designs of corrugated diaphragm structures.The dynamic structure analyses including: taking flat diaphragm as an example,the comparison between the finite element numerical solutions and the analytical solutions of modal frequencies are made to verify the reliability of the finite element method at first.Then,taking sinusoidal corrugated diaphragm as an example,the effects of thicknesses,heights and numbers of ripples on the free vibration modal frequencies and pre-load vibration modal frequencies are studied.In the end,the dynamic and static mechanical properties of the corrugated diaphragm with varying depth are studied.The temperature drift of pressure sensors will affect the accuracies of pressure measurement.To eliminate temperature drift,three software compensation algorithms,i.e.piecewise linear interpolation methods,two-dimensional regression analysis methods and polynomial fitting and Newton interpolation methods,are studied by the Matlab software,respectively,to compare their compensation accuracies.The simulation analyses of dynamic and static mechanical properties of the corrugated diaphragms and the simulation analyses of temperature compensation algorithms are two important factors in the whole development process of pressure sensors.The researches of these two parts in the work can provide some references for optimal designs of pressure sensors.