The working principle of capacitive touch screen

The working principle of Capacitive Touch Screen

To realize multi-touch on the capacitive Touch Screen, it relies on increasing the electrodes of mutual capacitance. Simply put, it is to divide the screen into blocks. Setting a set of mutual capacitance modules in each area works independently, so the Capacitive Touch Screen Panel can be tested independently. After processing the touch conditions of each area, multi-touch is simply realized.

The capacitive touchscreen is a four-layer composite glass screen. The inner surface and the interlayer of the glass screen are each coated with a layer of ITO (nano tin metal oxide). The outermost layer is a protective layer of silica glass with a thickness of only 0.0015mm. The interlayer ITO coating is used as a protective layer. On the working surface, four electrodes are drawn from the four corners, and the inner ITO is the screen layer to ensure the working environment.

When the user touches the Pcap Touch Screen, due to the electric field of the human body, the user's finger and the working surface form an exchange capacitance. Because the working surface is connected to a high-frequency signal, the finger absorbs a small current, which flows from the four corners of the screen. Allowed in the electrodes, and theoretically the current flowing through the four electrodes is proportional to the distance from the finger tip to the four corners. The controller obtains the position through the precise calculation of the four current ratios. Can reach 99% accuracy, less than 3ms response speed.