Elektrosil's Multi-Point Touch
Normally, a touchscreen simply emulates the computer mouse, but the multipoint-touch function offers much more: the possibility to either have more than one specific touch hit in order to support multiple mouse pointers, or to use those multiple touch hits and the movement of the virtual mouse pointers to interpret gestures. For example, two fingers moving in opposite directions could be interpreted as zooming a picture in or out.
The vast majority of all applications still running are based on the Windows XP operating system, which is a big problem, as Windows 2000/XP/XPe OS does not differentiate between different mice. So the graphical user interface and the mouse subsystem only have a single-point structure. Hence the normal way to implement a new device by simply installing a driver is not possible for two reasons: first, the operating system is not able to deal with more than one pointing device; and second, the GUI does not support any kind of gesture-interpretation. So a multipoint touch functionally only can be realised with an application-specific solution.
Elektrosil´s infrared multipoint touchscreens use the principle of a light barrier. IR-LEDs and phototransitors are placed on a pcb-frame and create a grid of IR light beams. For a dual-point input method, which is sufficient for zoom or rotation functions, Elektrosil offers a solution with definite X/Y coordinate couples. Any function like zooming, rotating or mouse-clicking must be implemented in the application software. The company also offers software support and a source code library, which helps customers to program their own application must faster. For a real multipoint input method, touchscreens with up to 7 coordinate couples are also available.