Although modern PCs are tied to their keyboards, touch-screen technology takes the place of a keyboard and mouse for smartphones and a host of other devices. To sense the position of your fingertips, the touch screen employs a digitizer, a component that turns the screen into a set of coordinates on a grid. The digitizer tracks the movement of your fingers in real time, to control actions such as tapping out a text message, shooting a target in a game or bringing up the latest weather report.
Form and Location
Typically, a touch-screen digitizer is one piece in a multilayered "sandwich." In modern devices, the screen that produces the images is found at the bottom layer; the digitizer is a transparent sheet that occupies a middle layer on top of the screen, and a thin sheet of hard, protective glass forms the top layer.
The digitizer layer contains a set of microscopically small sensors arranged in regular rows and columns all over its surface. Touching the screen triggers sensors immediately under your fingertip; a specialized electronic circuit receives signals from these sensors and converts them into a specific location on the screen as X and Y coordinates. The circuit sends the location to software that interprets the touch and location according to the app you're using. For example, when you dial a phone number, your fingers touch the numbers on a virtual keypad on the phone's screen. The software compares the locations touched against the keypad and generates a phone number one digit at a time.
Devices that use touch-screen technology include smartphones and tablet computers. Because they don't require a dedicated keyboard, the usable screen size is maximized without compromising any capabilities. Graphics tablets used by artists and industrial designers also employ digitizers, as do ATMs and information kiosks. Because traditional keyboards and mice can be vulnerable in dusty or dirty environments, some industrial machines use touch screens for monitoring and control.
In recent years, an improved digitizer system called multitouch has brought more convenience to smartphones and other mobile devices. Multitouch tracks two or more fingers on the screen at the same time, allowing sophisticated gestures such as shrinking a picture by pinching it.
How the Digitizer / Touch Screen Works
There are two layers of glass for the digitizer assembly. The first is simply glass, which is what you touch. The second is attached to the glass and senses the touch via an electrical field which transmits and receives based on the "return" from your finger or stylus. The digitizer and LCD work independently from one another. So if one fails, it won’t necessarily cause the other part to fail. With cracked glass, you can see the content on your screen, but there is broken glass which makes it hard to see. Cracks, splinters, and shattered glass can be present while the digitizer is still responsive. However, the digitizer can fail over time.
Preventive measures include using a case for your phone that creates separation between objects and the screen. Cases that don´t create a ridge on the glass side of the screen may be fashionable, but they don't protect the glass. And screen protectors will only prevent scratches.
Digitizer (Touchscreen) Failure is when a phone stops responding to touchscreen commands. This can occur with impact damage (usually associated with cracks in the glass), extreme heat (such as lying in the sun for extended periods of time) or water damage to the device.
Remember that glass can scratch from a variety of things, including keys and rough surfaces such as concrete or pavement. Glass can be replaced to make your cell phone look new again. But try not to drop your phone!
Use a screen protector to prevent any kind of damages, but remember a hard case is always better. It's always cheaper to buy a case than having to replace or repair your device.