At the end of the Asus press conference at Computex 2011, Chairman Jonney Shih waited until the very last minute to unveil the best product of the night: The Asus PadFone, a convergent device that docks an Android smartphone into the back of a slate so that they can be used together as a single device.

You can dynamically switch between phone and tablet display while your phone is docked in. The PadFone is essentially a symbiotic relationship between smartphone and slate, whereas the Atrix’s screen and keyboard dock are intended to replace your netbook or laptop. It’s a concept that owners of both Apple iPhone and iPad wish were possible: To dock the former into the latter and quit having to use two separate devices.

The screen size of the tablet is 10.1-inches, while the Smartphone has a 4.3-inch one. The tablet dock also has a built-in battery that will extend the life of the one in the Smartphone.

The usage scenarios are evident with such a solution: Say you’re surfing the Web on the smartphone and find that the screen is too small for certain websites. You would rather love to enjoy the web surfing on the tablet like your PC, as well as you can be indulge to create mobile sites, which are already customized for phones only, with uses of docked Smartphone inside. You can stop what you’re doing, dock the phone, and pick up where you left on the tablet. This also applies to composing email, video conferencing, and playing media. Right now, the details are so limited that it sounds like this game-changing device is still a while away. But if it does come to fruition, it could be the future of tablet computing.