The Characteristic Analysis of the Plane Type Capacitance Sensor with the Dummy Electrode

Abstract

Authors introduce here the plane type capacitance sensor for the human body detection technology used for realization of nursing care equipment. Since this sensor has characteristic form, it is used installing in equipment. In this sensor, it is necessary to distinguish the big difference of permittivity between human body and general objects on a seat, even when cushion material exists between objects and sensor in practical use. The useful results of simulations for the sensor properties with dummy electrodes are presented. The capacitance values in a 2-dimensional model were calculated with the FEM analysis. It becomes possible to acquire high capacitance by setting up dummy electrodes in the inner side and outside of measurement electrodes in the plane type capacitance sensor, and an object can be distinguished according to the difference of the capacitance by the difference in the relative permittivity. Furthermore, the sensor that we proposed showed the detection possibility of the size of an object.