yeah, but how exactly do they implement FTIR? I'm pretty shure now, that it's just a beamer behind the screen and beneath that is camera to detect the finger movement. As massimo allready noted, there's no room light. I guess the contrast of the FTIR image would be too low in this case.
Yeah, I can't see how its working, too! Especially because the emphasize that it's low-cost. Well there is a sketch http://mrl.nyu.edu/~jhan/ftirsense/ but I have no clue how they detect the light. Is it just a row of light sensors on each border of the frame?