The X and Y electrodes on the projected capacitive touch screen have an insulation layer in between them. ITO and a metal bridge are typically used to create a diamond pattern on the transparent electrodes.
The water in the human body makes it conductive. The conductivity of the human body is used by projected capacitive technology. A capacitance coupling occurs between a human finger and the electrodes when it touches a sensor with an X and Y electrode pattern, changing the electrostatic capacitance between the X and Y electrodes. The location and change in the electrostatic field are detected by the touchscreen controller.
A glass substrate serves as the bottom layer of a resistive touch screen, and a film substrate—typically clear polycarbonate or PET—serves as the top layer. Both layers are coated with a transparent conductive layer (ITO: indium tin oxide), and they are spaced apart by spacer dots to create a tiny air gap. The ITO material's two conducting layers are positioned face to face. The conductive ITO thin layers are in contact when a user touches a portion of the screen with their finger or a stylus. The resistance is altered. The RTP controller determines the touch position after noticing the change. This voltage shift serves as a pointer to the point of contact.
Resistive touch screens still reign in cost-sensitive applications. They also prevail in point-of-sale terminals, industrial, automotive, and medical applications.
The projected Capacitive Touch Panel (PCAP) was invented 10 years earlier than the first resistive touchscreen. But it was not popular until Apple first used it in iPhone in 2007. After that, PCAP dominates the touch market, such as mobile phones, IT, automotive, home appliances, industrial, IoT, military, aviation, ATMs, kiosks, Android cell phones, etc.