Multi Fields Coupled Dynamics Theory Research Of Thin Film Type Micro Resonant Pressure Sensor

Sensor technology is an important symbol in the development of modem science and technology. It is one of the three pillars of modern information industry. Among all kinds of sensors, the micro resonant pressure sensor has wide applications, which is characterized by its small size, high accuracy, excellent stability and convenient interface with digital electronics. The multi field coupled vibration characteristics of resonance film for thin film type micro resonant pressure sensor is studied. The design, manufacture and test of the sensor are completed.In this paper, a multi-fields coupled dynamic model of micro resonant film system is established with the consideration of molecular force and air damping effect comprehensively. According to the small deflection theory and the large deflection theory, a multi-fields coupled dynamics equation of the micro film is presented which includes mechanical force, molecular force, electrostatic force and fluidic damping force. The second order approximate solution of the nonperiodic vibration equation of micro film is calculated by Multi-scale method. The multi-fields coupled free vibration of the micro film is investigated. The multi-fields coupled forced response of the micro film near natural frequency is analyzed. The multi-fields coupled natural frequencies of the micro film and their changes along with system parameters are discussed. Amplitude frequency characteristics of the micro film under the coupled fields are given.For the two kinds of boundary conditions, the sensitivity of thin film pressure sensor is analyzed, the sensitivity equations of two kinds of thin film system are deduced. The influence factors of sensitivity is analyzed. The natural frequency and the influence factors of sensitivity in different pressures are analyzed. The results show that system sensitivity depends on many facts, The sizes of pressure film are the crucial factors. With increase of pressure, the system sensitivity decreases.Using ANSYS simulation software, the solid model of thin film pressure sensor is given, the stress simulation of the pressure sensor is completed. The modal simulation of the thin film is completed. Comparison of the simulation results and theoretical results shows that the correctness of the theoretical analysis.The chip of thin film type micro resonant pressure sensor is designed and manufactured. The sensor is packaged as well. Based on the principle of electrostatic excitation capacitance test, the micro film resonant frequency detection experiment is carried out. The test of natural frequency and sensitivity in different pressure is completed. The results show that the theoretical results with the consideration of molecular force are more close to the experiment resules.