The touch screen monitor has been around almost as long as computers themselves. Invented in 1971 by Dr Samuel Hurst they have found a use in a wide variety of applications.
The main advantage of a touch screen monitor is that it both acts as an input and output device. A single touch screen monitor can replace an existing CRT (cathode ray tube), plasma or LCD monitor and replace the keyboard and mouse too.
Touch screen monitors work by a variety of different methods but the basic function of using a graphical user interface (GUI) that is sensitive to touch is fundamental to all approaches.
Recognising a person's touch is done by several methods, the most common being resistive, capacitive, infrared and acoustic wave.
Different methods are used for the different functions that a touch screen may be required to fulfill. For instance, resistive touch screens work by using conductive and a resistive metallic layers between a sheet of normal glass. An electrical current runs through the two layers and when a user touches the screen, interference in the electrical field is caused and the computer then calculates the coordinates.
Resistive touch screens are quite durable although they can be scratched which can reduce their efficiency but overall they are the most versatile system.
While surface acoustic wave technology used in some touch screens uses ultrasonic waves that pass over the panel. When the panel is touched, a portion of the wave is absorbed and this can be measured identifying the location of the touch. Unfortunately surface wave panels are easily damaged and contaminants on the surface will hinder its function but they offer a higher clarity than the resistive system making them better suited to laboratory work.
Capacitive touch screens that use an electrical charge that is soaked up when a user touches it rather than being resisted like a resistive system makes them more durable. Capacitive touch screens are therefore a mainstay of industrial computers because of their durability and their imperviousness to moisture, dirt and grease. Other touch screen technology including infra-red or strain gauge are used too but are less common.
Touch screens are a viable alternative to the standard monitor, mouse and keyboard assembly adding better durability and resistance to contaminants whilst also forgoing the need for wires and peripherals making them ideal for industrial or manufacturing purposes.
Richard N Williams is a technical author and a specialist in the industrial computer industry helping to develop industrial computers and protection for all environments. Please visit us for more information about touch screens or other industrial computer solutions.