A Planar Capacitive Sensor for 2-Dimensional Long-range Displacements Measurement

摘要

A planar capacitive sensor (PCS) capable of 2-dimentional large scale measurement is presented in this paper.Displacement interpretation depends basically and independently on measuring the periodic variation in capacitance caused by the change of overlapped area of sensing electrodes on a moving plate and a fixed plate.Accumulating the number of quarters in each direction and the specific position in the final quarter,large scale measurement is fulfilled.X and Y direction displacements can be measured independently and simultaneously.A finite element simulation shows smaller gap distance and larger electrode length would guarantee better sensitivity.Experiments based on PCS prototype demonstrate that the PCS has a resolution of 0.038μm,and a sensitivity of 0.122mV/μm.High potential of PCS as an innovative 2-D long-range displacement sensor is authenticated.