Expansion of detectable area by floating electrodes in capacitive three-dimensional proximity sensor

In the capacitive proximity sensing method, arranging multiple sensing electrodes makes it possible to obtain the three-dimensional position of a nearby object. The author has developed a capacitive proximity sensing method using LC resonance in three reactance elements. In this method, the detectable area can be greatly extended by the floating electrodes, which are capacitively connected to the sensing electrode. By connecting multiple floating electrodes in series, the detectable range can be extended up to the length of the array of floating electrodes. When these electrodes are arranged on a frame, the region surrounded by the frame becomes the detectable area. By applying this frame on any surface, it is possible to make the surface within the opening of the frame a non-contact operating panel, which can be applied as a gesture input device.