US Patent 9001080 Touch-panel device

A touch panel device includes a touch panel including first and second electrodes, an alternating-current (AC) signal source operable to input an AC signal into the first electrode, an inductive element electrically connected in series between the AC signal source and the first electrode, and a detection circuit operable to detect a change of a capacitance between the first electrode and the second electrode upon a touch of an object on the touch panel, based on a change of a signal output from the second electrode. This touch panel device can enhance detection sensitivity with a simple configuration.