A touch screen is an input device that allows the user to interact with the computer by touching the display screen.
Early screens used beams of infrared light projected across the screen surface. Interrupting the beams generated an electronic signal identifying the location of the screen, which was relayed to software.
Modern touch screens use a thin, durable, transparent plastic sheet overlayed onto the glass screen. The location of a touch is calculated from the capacitance for the X and Y axes, which varies based upon where the sheet is touched.
The HP-150 was among one of the world's earliest commercialized touch screen computers. It actually has not a touch screen in the strict sense, but a 9" Sony CRT surrounded by infrared transmitters and receivers which detect the position of any non-transparent object on the screen.
It was popularised for use in video games by the Nintendo DS.
Different technologies:
- Capacitive
- Resistive
- Infrared
- Surface Acoustic Wave (SAW)
See also: Liquid crystal display television, Tablet PC.
External links
References
