The principle of touch switch: When a person touches the capacitive screen, the user's finger and the working surface form a coupling capacitance due to the electric field of the human body. Because the working surface is connected with high-frequency signals, the current absorbed by the fingers is very small, which flows out from the electrodes at the four corners of the screen respectively. Theoretically, the current flowing through the four electrodes is directly proportional to the distance from the finger to the four corners. The controller obtains the position by accurately calculating four current ratios.

The structure of capacitive touch screen is mainly to plate a transparent film on the glass screen, and then put a protective glass outside the conductor layer. Double glass design can completely protect the conductor layer and sensor.

Extended data:

Touch switches are divided into resistive touch switches and capacitive touch switches according to the switching principle, and single-wire touch switches and double-wire touch switches (live and zero wires) according to the connection mode.

From a global perspective, most countries adopt the wiring rules of single-wire system. Therefore, the early touch switch was mainly controlled by single fire line. With the deepening of application, the stability of neutral line and live line control is higher and the load of switch is greater. The market is dominated by zero-sum firewire control. Touch-sensitive operation panel has been rapidly applied in many fields with its sturdy, wear-resistant, insulating, dustproof and waterproof appearance, and has become a hot technology.

Baidu encyclopedia-touch switch