In recent years, with the rapid development of electronic technology, touch screen is more and more popular among consumers. At present, touch screen is more and more widely used in POS terminals. The size of POS terminals is mostly small, ranging from 3-4.3 inches to 11.6-15.6 inches. The capacitive touch screen is widely used by some merchants, who prefer to use capacitive touch screen because its inductive touch is convenient, more intuitive and convenient to operate.
The structure of capacitive touch screen is mainly to plate a transparent film layer on the glass screen, and then a piece of protective glass on the outside of the conductor layer. Double glass design can completely protect the conductor layer and inductor. In addition, the additional touch screen is plated with long and narrow electrodes to create a low-voltage AC electric field in the conductive body. When the user touches the screen, a coupling capacitor will be formed between the human body's electric field, finger and conductor layer. The current from the four electrodes will flow to the contact, and its strength is proportional to the distance between the finger and the electrode. The controller located behind the touch screen will calculate the ratio of current and strength and accurately calculate the position of the touch point. The capacitive touch screen's double glass can not only protect the conductor and sensor, but also effectively prevent the influence of external environmental factors on the touch screen. Even if the screen is stained with dirt, dust or oil, the capacitive touch screen can still accurately calculate the touch position.
