Most panels and controllers out there suffer from about a 100ms delay. For taps and slow swipes that's not an issue but, as you wing your finger around the screen faster and faster (say, while quickly doodling in a painting app), the lag becomes quite apparent. The powerful minds over at Microsoft Research have figured out a way to get that delay down to a measly 1ms.
Really amazing video demonstration.Skip to around 0:52.
P.S - u can test it with ur iphone or ipad