Patent attributes
A key unit and a keyboard using the same are provided. The key unit includes a circuit board, an elastic element, a keycap, and a processing circuit. The circuit board includes a capacitance sensing circuit embedded therein, and the capacitance sensing circuit includes a pair of sensor electrodes. The elastic element is disposed on the circuit board. The keycap is moveably disposed above and spaced apart from the circuit board. The elastic element is disposed between the keycap and the circuit board so that the keycap moves between a non-depressed position and a depressed position with respect to the circuit board. The processing circuit is electrically connected to the pair of sensor electrodes to obtain a variation of a coupling capacitance between the pair of sensor electrodes and to determine whether the keycap is touched or depressed according to the variation of coupling capacitance.