公开(公告)号：US07383737B1

公开(公告)日：2008-06-10

申请号：US11693202

申请日：2007-03-29

申请人： Yingjie Lin ,  Carlos A. Urquidi ,  Francisco Romo

发明人： Yingjie Lin ,  Carlos A. Urquidi ,  Francisco Romo

IPC分类号： G01L9/12

CPC分类号： G01L9/0072

摘要： A capacitive pressure sensor includes a electrically conductive, generally piston shaped diaphragm with a flexible base wall configured to deflect under pressure. The diaphragm is generally U-shaped in cross section. The base wall includes an upper, flat sensing surface which acts as a capacitive electrode. The diaphragm further includes a step around a radially-outermost perimeter which is elevated from the flat sensing surface. A sensing electrode body is located on top of the step and creates a capacitive sensing cavity between the sensing surface and the bottom surface of the electrode body. On the bottom surface of the electrode body is formed a center, circular electrode and a ring electrode that surrounds the center electrode. The center electrode and the sensing surface form a variable capacitor which changes with pressure and the ring electrode and the sensing surface form a reference capacitor. A circuit determines a differential capacitance between the variable capacitor and the reference capacitor and generates a pressure signal indicative of the fluid pressure applied to the diaphragm. A spring ring holds the sensing electrode body against the diaphragm when assembled. The diaphragm can be a machined metal part or a sheet metal cup. The sensing electrodes and signal generating circuit can take the form of a hybrid circuit.

摘要翻译： 电容式压力传感器包括导电的，大体上活塞形的隔膜，其具有被配置为在压力下偏转的柔性底壁。 隔膜的横截面通常为U形。 底壁包括用作电容电极的上部平坦的感测表面。 隔膜还包括围绕从平坦感测表面升高的径向最外周边的台阶。 感测电极体位于步骤的顶部，并且在感测表面和电极体的底表面之间产生电容感应腔。 在电极体的底表面上形成围绕中心电极的中心圆形电极和环形电极。 中心电极和感测表面形成可变电容器，其随压力而变化，并且环形电极和感测表面形成参考电容器。 电路确定可变电容器和参考电容器之间的差分电容，并产生指示施加到隔膜的流体压力的压力信号。 组装时，弹簧环将感测电极体固定在隔膜上。 隔膜可以是加工的金属部件或钣金杯。 感测电极和信号发生电路可以采用混合电路的形式。