Projected capacitive (pro-cap, pcap, or PCT) touch technology is used in such popular handheld devices as smartphones and tablets. Only recently has the technology been able to be scaled up for use in large screen applications like multitouch tables.
How does pro-cap work? Touch is detected when a finger or stylus comes in contact with the surface which signals a change in the system’s electromagnetic field and capacitance. The change, triggered by the touch, is then pin-pointed and converted to locations on an X, Y grid that the system uses to determine the placement of the touch. A conductive grid pattern of is applied to film or glass to create the projected capacitive field.