MIT's camera-embedded LCD screen
Almost three years ago MIT Media Lab researchers presented a gloveless gestural interaction system that incorporates optical sensors embedded directly behind an LCD display. Using the LCD display as a lens, the sensors can recognize and react to a human hand before the screen. The main obstacle at the time, according to the MIT News Office, is that LCD displays with built-in optical sensors weren't easy to find because they were an entirely new concept. The Media Lab had to produce mock-ups in order to test the technology.