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diffused surface illumination (touchscreen) (DSI)

Diffused Surface Illumination (DSI) is a technique that can simultaneously detect multiple touches from multi-touch sensitive screens. The DSI method is similar to Frustrated Total Internal Reflection( FTIR) and differs mainly in the infrared distribution. On the sides of the DSI display are infrared LED arrays that illuminate the display screen from all sides.

The display screen itself has a special plexiglass surface, contains tiny particles that act like micro mirrors and distribute the infrared light fed in from the edges evenly over the plexiglass.

When the display surface is touched by a finger or pen, the infrared light undergoes a different refraction and distribution, which is detected by the digital camera underneath and evaluated according to the coordinates. So that the user can follow his action on the screen, the calculated touch point is displayed on the screen.

Principle of Rear Diffused Illumination (DI)

Principle of Rear Diffused Illumination (DI)

The acquisition of the touch point and the evaluation of the coordinates is the same as for Diffused Illumination( DI) and Frustrated Total Internal Reflection (FTIR). The method is susceptible to ambient light and contamination of the screen. It can be used in screens of any size and simultaneously detect any number of touch points. A disadvantage is that it must be recalibrated regularly.

Informations:
Englisch: diffused surface illumination (touchscreen) - DSI
Updated at: 24.01.2013
#Words: 209
Links: method, frustrated total internal reflection (multitouch) (FTIR), infrared (IR), display, infrared LED (IR-LED)
Translations: DE
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