The document discusses different types of touch screen technologies. It provides a brief history of touch screens, describing the first touch sensor developed in 1971 and first transparent touch screen in 1974. It then explains the basic components and functioning of touch screens, including touch sensors, controllers, and software drivers. The document goes on to describe various touch screen technologies like resistive, capacitive, surface wave, and infrared technologies; and their advantages and disadvantages. It concludes by discussing applications of touch screens in public displays, customer self-service, and other areas.