On the back would lie an electrical tactile display, and whenever you touch the touch panel, it will send an electrical touch at the same spot on the back. This translates to you actually touching the front screen while giving the feeling that said touch is going through the screen and being traced on your palm. Should there be icons or graphics on display, they too, can be felt on your palm. Guess screen sizes are irrelevant here since that will largely depend on the size of your palms.
How will this technology change the way we use touchscreen displays, and will it be the next evolutionary step? Perhaps not quite just yet, as it is still in the experimental stage, although not running the risk of breaking your “touchscreen” is something worth thinking about.