There are currently several types of touch screens, including resistive (double-layer), surface capacitive and inductive capacitive, surface acoustic wave, infrared, as well as bending wave, active digital converter, and optical imaging. They can be divided into two categories: one requires ITO, such as the first three types of touch screens, and the other does not require ITO in their structure, such as the latter. Currently, there are mainly several types of touch screens, including resistive (double-layer), surface capacitive and inductive capacitive, surface acoustic wave, infrared, as well as bending wave, active digital converter, and optical imaging. They can be divided into two categories: one requires ITO, such as the first three types of touch screens, and the other type of structure does not require ITO, such as the last few screens