A touch screen allows user commands to be issued by pressing corresponding buttons on the screen. Since their introduction in the 1970s, touch screens have become popular for computer and media technology. Chances are, if you have used an automated teller machine (ATM), owned a personal digital assistant (PDA), or played with the newer cell phones, you have already used touch screen technology.
There are several commonly used systems that allow for touch screens to work. Each method allows for commands to be translated by the computer as a result of touching a certain point on the screen. Many convert the coordinates of the touch locations to specific actions to be taken by the system.
One of the most common systems for touch screens is called resistive. Covering the transparent panel of the screen are conductive and resistive metallic layers that have an electric current between them. When the screen is touched, the electrical current can tell the exact spot of contact and send the coordinates to the operating system. This is similar to how a mouse works with a computer, where the central operating system notes the exact point of a click and can respond by activating the action requested.
Capacitive systems give a brighter and clearer image than resistive technology, as the electric layer on the monitor allows more light to pass through. These touch screens carry an electrical charge that reacts to the electrical fields of the human body. Circuits at each corner of the screen measure the distortion that occurs when you touch the screen and cause the operating system to react.
Strain gauge touch screens are often to be found on public ATMs. By using a spring mechanism in the corners of the screen, the strain gauge can measure the pressure put on a touch point. As anyone who as ever used an old ATM can tell you, the pressure points can wear out with use, preventing the machine from responding correctly.
Touch screens are considered useful in that they eliminate excess hardware such as computer mice and keyboards. Some experts believe that the day is not far off when personal computers will consist solely of a monitor and central processing unit. With the trend of making portable devices lighter and more compact, touch screen technology may also soon be as common for laptop computers as it already is for small mobile devices like cellular phones.
It can take considerable pressure to activate a touch screen, resulting in strain on the fingers and hands if used consistently. Some PDAs and smartphones include a thin instrument called a pen or stylus, which not only reduces strain but also allows greater precision. As touch screen technology becomes more prevalent for mobile devices, a stylus can be used to type on full touch screen keyboards and play mobile video games.