US Patent 10075163 Contact sensing device

A contact sensing device includes: a first electrode and a second electrode facing each other, a drive detection circuit of an electrostatic capacitance type, a first switching circuit that implements switching between connection and disconnection between the first electrode and ground, and a second switching circuit that implements switching between connection and disconnection between the first electrode and the second electrode. The drive detection circuit implements switching between a first state and a second state and detects an electrostatic capacitance change in the first state and an electrostatic capacitance change in the second state.