Knowledge

Overview of how capacitive touch screens work



Capacitive screen to achieve multi-touch, relying on the increase of mutual capacitance of the electrodes, simply said, is to divide the screen, in each region set up a set of mutual capacitance module is independent work, so the capacitive screen can independently detect the touch of each region, after processing, simple to achieve multi-touch. Capacitive Technology The touchscreen CTP (capacity touch Panel) works by using the human body's current sensing. 

Capacitive screen is a four-layer composite glass screen, the inner surface of the glass screen and the sandwich layer of Ito (nano-indium tin metal oxide), the outermost layer is only 0.0015mm thick silica glass protective layer, the sandwich ito coating for the face, four angle leads to four electrodes, the inner layer Ito for the screen layer to ensure the working environment. When the user touches the capacitive screen, due to the human field, the user's finger and the working face form a coupling capacitance, because the work surface is connected with high-frequency signal, so the finger absorbs a very small current, the current from the screen of the four angle of the electrode outflow, and theoretically through the four electrodes of the distance between the fingers to the square, The controller obtains the position by the precise calculation of four current ratios. Up to 99% accuracy, with a response speed of less than 3ms.