What you are 'missing' and the folks who watched minority report or Avatar are lusting after, is a transparent piece of material that they can display stuff on.<p>True, LCDs are, by their nature, transparent. However their contents are only 'visible' when there is light going through them, and they work by adjusting how much light passes through them using polarization. If you have a full spectrum light behind them, and you have red green and blue dots which you use for color selection, you get a color LCD.<p>However, these don't <i>generate</i> light. And no, nobody has built one of those yet. To build such a display would no doubt require that you build a pixel out of three (or four) LEDs that are nominally transparent, such that turning them on would cause the pixel to appear.<p>That would then make for a display which was clear, except for where it had data showing. So far, this technology (outside of using a projector to project the display on to a window where the user sees the reflection as the display) does not exist.