I strongly believe that the integration of touchscreen into smartphones was most beautiful innovation of the mobile industry. It lets you use the maximum real estate of device without compromising with core features. It’s a screen when watching videos, produces qwerty when typing, acts as an on screen game controller and the list goes on.
Its not that the touchscreens eliminated the physical keypads immediately after their adoption. Initially, they just replaced the normal screens and were integrated along with the physical keypads. But with features like of on-screen keyboards, handwriting recognition, slide and all, they just kept growing their area and finally acquired the entire front area. Today, the candy bar touchscreen is the most popular form factor across all mobile platforms and no doubt, it will be there for a long time.
We started with a stylus, then resistive, then capacitive and then what? The innovation in this area seems to have stopped from last couple of years. Either the innovators have run out of ideas or they are busy in developing SIRI and its cousins.
The consensus on the next big technology for the touchscreen varies widely. However, depending on the prototypes available today, we can list a few technologies which may turn in to reality in the near future.