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IQS Newsroom Articles on Touch Screens
Touch Screens
Touch screens are displays that are able to detect the
presence and location of human touch within a computer screen without using a
mouse, touchpad, keyboard or stylus (writing utensil). It is a
pressure-sensitive computer display screen that also acts as an input device.
Users are able to interact with the computer by touching images and text. It is
quickly becoming the main method of human machine interface (HMI) in
industrial, commercial and business systems. The retail, hospitality, manufacturing,
military, aerospace, medical, entertainment, transportation, automotive and
banking industries all use touch screens as a part of their computer systems.
Restaurant computer systems, cash registers and hand held electronics are the
most common items that regularly have touch screens.
There are three main types of touch screens—resistive,
capacitive and surface acoustic wave. Resistive touch screen systems are
composed of two layers: a scratch-resistant glass panel and a conductive and
resistive metallic layer. When a finger touches the glass screen, the two
layers touch each other in that spot, which changes the electrical field and is
calculated by the computer. The capacitive system’s glass panel is covered by a
layer that stores electrical charges. When a finger touches, the charge is
transferred to the user and decreases on the capacitive layer. The computer
system then calculates the difference. Finally, the surface acoustic wave
system is composed of a receiving and sending transducer and reflectors that
transfers an electrical signal from one transducer to another. The receiving
transducer knows if the wave has been disturbed by a touch and is able to
locate it. Resistive systems only transmit 75% of light from the monitor,
giving the monitor a much less clear picture than the other two systems, which
transmit between 90 and 100% of light.
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