非接触式电容压力传感器敏感元件的设计及性能分析

Design and Simulation of Sensitivity Diaphragm of Untouched-Mode Capacitive Pressure Sensor

将中心岛膜结构的压力敏感膜用在非接触式电容式压力传感器中,解决了平膜结构带来的各点挠度不同、非线性和需要后续补偿电路的问题。通过对材料为多晶硅的中心岛膜进行结构优化设计和挠度、应力等力学性能分析。计算了在不同外加压力条件下压力敏感膜的电容数值、灵敏度和线性度。根据优化设计,外加压力在0.2～1.4×10^5Pa间变化时,电容值在0.0251～0.0281pF间变化;通过分析两种结构敏感膜在XY面内同一位置与中心挠度差的变化率,中心岛膜结构的变化率为49.4%低于平膜结构1.7%。因而中心岛膜结构比平膜结构有更好的灵敏度和线性。

Central island structure of the sensitive diaphragm used in untouched-mode capacitive pressure sensor solved the problem of the different, nonlinear, compensation circuit complexity. Through the optimization structural design for polysilicon sensitivity diaphragm, flexibility, stress and other mechanical properties also be analyzed. Capacitance values, sensitivity and linearity of the sensitive diaphragm are calculated at different applied pressure. According to the optimizing design, when applied pressure varying between 0. 2-1.4×10^5Pa, capacitance value changed between 0. 0251-0. 0281 pF. By analyzing rate of flexibility in XY plane at the same position of the two different diaphragm structure. Central island structure is 49.4% below the plane diaphragml. 7%. Central island structure has a better sensitivity and linear.