Capacitive displacement sensor for detecting planar submicrometer motion

This paper describes the design of a very simple displacement sensor that measures the change in the position of an object by sensing the change in capacitance due to the movement of this object in the sensor fringing electric field. Two sensor geometries with small footprints were considered and several sensor variations were built and tested. At distances of approximately 0.5 μm and 30 μm, test results demonstrated that the sensors' resolution was in the order of tens of nanometers.