Nearly all standard TRU-Vu monitors are available with resistive or capacitive touch screens, and USB or RS-232 versions.
A resistive touch screen system consists of a glass monitor panel that is composed of several layers. The two most important are two thin metallic electrically conductive and resistive layers separated by a thin space. When a object touches the touch screen panel, the layers are connected at the exact point. The change in the electric field is noted and the coordinates of that point are calculated by the computer, much the same as a mouse driver translates a mouse click or drag.
Resistive touch screen panels are generally the most affordable technology but only offer about 70-75% clarity (vs. 90% for capacitive), and the outer layer can be damaged with sharp objects. Resistive touch screen panels are not affected by outside elements such as dust or water; they are the most common type used today.
In a capacitive system, the monitor panel is coated with a layer of indium tin oxide, which conducts a continuous electrical charge across the surface. When a user's finger touches the surface, the charge on the capacitive layer decreases. This decrease is measured in circuits located at each corner of the monitor. The computer calculates exactly where the touch event took place and then relays that information to the touch screen driver software. Its primary advantage is that it transmits 90% of the light from the monitor, whereas the resistive system only transmits about 75%. This gives the capacitive system a much clearer picture than resistive technology. However, a capacitive system only responds to finger contact and will not work with a gloved hand or pen stylus.
For OEM projects, we also offer SAW and Infrared touch screen monitors.
Contact us for more details. Data sheets will be available shortly.
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