A keypad assembly includes a PCB, a light guiding board disposed on the PCB, a panel disposed on the light guiding board, a plurality of panel portions made of transparent material, set on the panel, a lighting device disposed on the PCB, and a sensing device disposed on the PCB. when an object touches or slides on/above the surface of the panel portion, the intensity of light sensed by the sensing device changes which causes the current of the four sensors to be changed, thus the sensing device generates a signal to complete a corresponding information input.