Surface Capacitive Technology is a technology for touch screens based on the surface capacitance of the display. This process is used in large displays and works with a transparent electrode film applied to the display panel. The electrode film is protected by a protective layer.
The electrode film has electrodes at the four corners to which an electric voltage is applied, creating a homogeneous electric field across the display. When a finger touches the screen, current flows from the electrodes through the finger via capacitive coupling between the electrode layer and the finger. The coordinates at which the finger touches the screen are determined from the ratio of the current, namely the current flow from the electrodes through the finger is inversely proportional to the distance between the electrodes and the finger.