Already done...

This idea has be repeated time and time and time again. Kudos for thinking of it indepentantly though!

Examples of this idea in practice:
iPad, Blackberry, Samsung Android, some laptops, some graphics tablets, so on and so on...

To give you some constructive criticism I would like to note that you could have added the text afterwards via PC to make it more legible, use clean paper that isn't scribbled all over and then erased and finally, spend more time on drawing the idea and develop it a bit more before you submit the idea to the art portal!