Ordinary touch screen basically only has mutual capacitance, which is used to realize multi-touch detection. There are two kinds of capacitive sensors on the touch screen supporting floating touch, mutual capacitance and self capacitance. Self-capacitance can generate stronger signals than mutual capacitance, the detection distance of finger induction can reach 20 mm, and the electric field of mutual capacitance sensor is very small, and the signal intensity is very low, so it is impossible to sense those very weak signals. Therefore, when the user's finger hovers on the screen, the mutual capacitance sensor cannot sense the signal. Self-capacitance sensor is larger than mutual capacitance sensor. Large sensors can generate powerful signals, so the device can detect fingers 20 mm above the screen. Floating touch is realized by running self-capacitance and mutual capacitance on a touch screen at the same time. Mutual capacitance is used for normal touch sensing, including multi-touch. And the self-capacitance is used to detect the finger hovering above. Because the floating touch technology relies on self-capacitance, it is impossible to realize floating multi-touch, that is, when floating, the screen does not support multi-touch, and the screen can only realize multi-touch when touching. By using the existing capacitive touch sensor and lowering the threshold of touch input, floating touch and contact touch can be distinguished. All Android apps work perfectly. As before, only applications that explicitly "listen" for hover touch events will respond. In other words, the implementation of floating touch technology needs the support of internal application programs.