Default [Q] Disable touchscreen?

Is there a way to deactivate the screen so you can watch video or use navigation etc without worrying about bumping the screen? It would be easier to watch a video while traveling without having to worry about it. I don't know how this would work- how you would reactivate the screen, etc. but this would be a useful feature for those of us on the run or for those of us with kids (watch cartoons, etc.)