Would you live without them. Your phone has one.
WHAT ARE TOUCH SCREENS
A touch screen is an electronic visual display that the user can interact with by using simple gestures touching the screen. You can zoom in and out click scroll and do basically everything you can do with a mouse.
HOW DO TOUCHSCREENS WORK
Most people take touch screens as granted but probably only 1 out of 25 people could tell me how they work. Touchscreens work in many ways each having their advantages and disadvantages. The one that is used most in places like hospitals, restaurant and factories is called resistive touchscreen. It comprises several layers, the most important of which are two thin, transparent electrically-resistive layers separated by a thin space. These layers face each other with a thin gap between. The top screen (the screen that is touched) has a coating on the underside surface of the screen. Just beneath it is a similar resistive layer on top of its substrate. One layer has conductive connections along its sides, the other along top and bottom. A voltage is applied to one layer, and sensed by the other. When an object, such as a fingertip or stylus tip, presses down onto the outer surface, the two layers touch to become connected at that point: The panel then behaves as a pair of voltage dividers, one axis at a time. By rapidly switching between each layer, the position of a pressure on the screen can be read.