surface capacitive technology
Surface Capacitive Technology is a technology for touchscreens based on the surface capacitance of the display. This process is used in large screens 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, generating 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 film and the finger. The coordinates at which the finger touches the screen are determined by a controller 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.
Another capacitive multitouch method is Projected Capacitive Touch( PCT), in which the screen is divided into a capacitive matrix.