The structure of capacitive touch screen is mainly to coat a transparent film body layer on the glass screen, and then add a protective glass outside the conductor layer. The double glass design can completely protect the conductor layer and the sensor, and at the same time, the light transmittance is higher. Can better support multi-touch.

The basic structure of capacitive touch screen is: the substrate is a single-layer plexiglass. A layer of transparent conductive film is uniformly forged on the inner and outer surfaces of the plexiglass, and a narrow and long cone is placed on the four corners of the transparent conductive film on the outer surface. electrode. The working principle of capacitive touch screen is: When the finger touches the capacitive touch screen, the high-frequency signal is connected on the working surface. At this time, the finger and the touch screen working surface form a coupling capacitor, which is equivalent to a conductor. Because there are high-frequency signals on the working surface, the finger When touching, a small current is drawn at the touch point. This small current flows from the electrodes on the four corners of the touch screen. The current flowing through the four electrodes is proportional to the linear distance from the finger to the four corners. The controller passes through the four currents. By calculating the ratio, the coordinate value of the contact point can be obtained.
A capacitive touch screen can be simply viewed 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. Floor. The innermost conductive layer is the shielding layer, which plays the role of shielding the internal electrical signals. The middle conductive layer is the key part of the entire touch screen. There are direct leads on the four corners or sides to detect the position of the touch point.
Since the capacitance varies with the contact area and the dielectric of the medium, its stability is poor, and drift phenomenon tends to occur. This kind of capacitive touch screen is suitable for the debugging phase of system development.