The benefits of such technology are obvious. Rather than lugging along extra input devices such as a mouse or a keyboard, the user need only his finger to manipulate the chosen device. But it’s not just mobile devices that benefit from this type of input. All kinds of devices can be equipped, including TV and computer monitors, LCD screens, and the older CRT computer monitors. As a result, a bartender can press on a screen to ring up drinks on a busy night rather than type in a price, a nurse can input patient information with one hand. Truly, the possibilities with touch screen monitors are endless.
Touch screen monitors usually come in three varieties that enable it to recognize a person’s touch. These are resistive, capacitive and surface acoustic wave. The resistive type works by having two panels with a thin space between them. When the user presses the screen, the two panels touch at that point, and the exact coordinates are then registered with the computer.
A capacitive system runs a small electrical charge throughout the touch screen. When the user touches the chosen area, some of the electrical charge is distributed to the finger, lessening the charge at that location. The coordinates are again recorded and sent to the computer. This type of touch screen produces a clearer picture because it transmits more light and doesn’t require two panels.
Finally, the surface acoustic wave system is the best, and results in the clearest picture. Transducers are used to send electrical signals across the screen, and if a user touches the screen, they can determine where based on how the electrical signal is received from one transducer to the other.
Since the capacitive system must have a finger to absorb electricity, most non-living objects won’t register as a touch. Resistive and surface acoustic wave systems on the other hand react to just about any form of pressure. Each has its different advantages as a result, and manufacturers will only find new ways to make use of them.
Finally, although touch screens provide a natural interface for computer novices, they are unsatisfactory for most applications because the finger is such a relatively large object. It is impossible to point accurately to small areas of the screen. In addition, most users find touch screens tiring to the arms after long use.