| 摘要 |
PROBLEM TO BE SOLVED: To provide an electrostatic capacitance sensor that enables prevention of a wrong action due to a water droplet.SOLUTION: The electrostatic capacity coupling type electrostatic sensor is configured to have an electrode made of a conductive material and a conductive member arranged in an insulator, and measure an electrostatic capacity of the conductive member and the electrode. In the measurement, the electrostatic capacity coupling type electrostatic sensor is configured to: generate a sin signal and a cos signal in synchronization with each other; apply the sin signal to an electrode group A10 made of a plurality of applied electrodes; multiply a signal subjected to electric current/voltage conversion of an output from an electrode group B11 by the sin signal and the cos signal; and measure a voltage converted to a DC signal through low-pass filters 21 and 22. By sequentially changing a combination of wiring for driving the electrode of the electrode group A10, wiring for connecting the electrode of the electrode group B11 via an electric current/voltage conversion circuit 15 and wiring for maintaining an unconnected state, the voltage converted to the DC signal is measured, a calculation process is implemented, and a state where a finger gets close to the electrode of the electrode group A10 and the electrode of the electrode group B11 and a state where an object is mounted on the electrode of the electrode group A10 and the electrode of the electrode group B11 are discriminated. |
