Editing Touchscreen (section)

===Infrared acrylic projection===
A translucent acrylic sheet is used as a rear-projection screen to display information. The edges of the acrylic sheet are illuminated by infrared LEDs, and infrared cameras are focused on the back of the sheet. Objects placed on the sheet are detectable by the cameras. When the sheet is touched by the user, [[frustrated total internal reflection]] results in leakage of infrared light which peaks at the points of maximum pressure, indicating the user's touch location. Microsoft's [[Microsoft PixelSense|PixelSense]] tablets use this technology.