The principle of operation for touch screens

The touch screen is a device that is a screen that responds to touch it. The touch screen was invented in the U.S. as part of research on programmed instruction. Computer system PLATO IV, appeared in 1972, had a touch screen on a grid of infrared beams, consisting of 16 × 16 blocks. But even such a low accuracy allows the user to choose an answer by pressing the right place on the screen. Touch screens were used mainly in industrial and medical instrumentation in those days. Touch screens are used in payment terminals, information stands, equipment for trade automation, handheld tablets, operator panels in the industry, electronic books. For information and vending machines, operator panels and other devices in which there is no active input, touch screens have proven to be a very convenient way humans interact with machines. Shortcomings do not allow you to use only touch-screen devices with which people work for hours. However, a competently designed touch-screen device might not be the only input device - for example, in the workplace teller touch screen can be used for quick selection of product, and the keyboard - to enter numbers. There are many different types of touch screens, which operate on different physical principles. The principle of infrared touch panel is simple - a grid formed by horizontal and vertical infrared beams, suspended in touch with the monitor any subject. The controller determines the location where the beam was interrupted. The glass panel is fitted with infra-red illumination. At the boundary glass-air turns total internal reflection at the interface glass - a foreign object light is scattered. This technology is used in devices such as Internet pad, handheld computer, an electronic book. To distinguish depression from hand presses any other object is a multi- technology, perhaps more tactile surface, up to a blackboard. Induction is a touch screen tablet with built-in screen. These screens only respond to a special pen. These screens are used when required response was to press a stylus (not by hand): art tablets class high-end, some computer models.