The substrate of the capacitive touch screen is a single-layer plexiglass, and a layer of transparent conductive film is uniformly forged on the inner and outer surfaces of the plexiglass, respectively, and a long and narrow electrode is tapped on the four corners of the transparent conductive film on the outer surface.
The working principle of capacitive touch screen:

When the finger touches the capacitive touch screen, the high-frequency signal is connected to the working surface. At this time, the finger and the working surface of the touch screen form a coupling capacitance, which is equivalent to a conductor. Because there is a high-frequency signal on the working surface, it is sucked away at the touch point when the finger touches it. A small current flows from the electrodes on the four corners of the touch screen respectively. The current flowing through the four electrodes is proportional to the straight-line distance from the finger to the four corners. The controller calculates the ratio of the four currents to obtain Output the coordinate value of the contact point.
The capacitive touch screen can be simply regarded as a screen composed of four layers of composite screens: the outermost layer is a protective glass layer, followed by a conductive layer, the third layer is a non-conductive glass screen, and the fourth innermost layer is also conductive layer. The capacitive touch screen manufacturer tells you that the innermost conductive layer is the shielding layer, which plays the role of shielding the internal electrical signals. The conductive layer in the middle is the key part of the entire touch screen. There are direct leads on the four corners or four sides, which are responsible for the touch screen. Detection of handle position.