The capacitive screen does not need to be calibrated, and only the resistive screen needs to be calibrated.
Capacitive touch screen technology uses the current sensing of the human body to work. The capacitive touch screen is a four-layer composite glass screen. The inner surface and the interlayer of the glass screen are coated with a layer of ITO. The outermost layer is a thin layer of bauxite glass protective layer. The interlayer ITO coating is used as the working surface, and the four corners are taken out. Four electrodes, the inner layer of ITO is a shielding layer to ensure a good working environment. When the finger touches the metal layer, the user and the surface of the touch screen form a coupling capacitor due to the electric field of the human body. For high-frequency current, the capacitor is a direct conductor, and the finger sucks a small current from the contact point. This current flows out from the electrodes on the four corners of the touch screen, and the current flowing through the four electrodes is proportional to the distance from the finger to the four corners. The controller calculates the position of the touch point by accurately calculating the ratio of the four currents. .
