How does the touch screen in a phone work and what are the different types of touchscreens available?

 

                           Touchscreens, whether in smaller devices like mobile phones or in tablets and touchscreen-enabled computers, work in the same manner. The older type of touchscreen (resistive) uses a thin layer of flexible polyester film over a layer of glass or plastic. The various layers are criss-crossed with near-invisible wires. When the top layer is pressed onto the lower layer (by a finger, stylus or any hard object), these wires intersect, changing the flow of current, which in turn helps in determining the location of the touch on the screen. A fair amount of pressure is required to register the touch, and a resistive touchscreen's sensitivity usually tapers off towards the edges of the screen. The newer (capacitive) touchscreens which are all the rage now, have uniform sensitivity are far more sensitive than resistive screens.

                         A thin, inflexible capacitive layer that holds current sits on top of the screen. When the screen is touched by a bare finger (or similar material that conducts electricity), the charge on the capacitive layer decreases at that point—which is used to decide the contact point. Since there is no flexible layer and no actual intersection of wires takes place, a touch on a capacitive screen can be registered with even the slightest touch.