Cellphone keypads
So what can we make them easier to use?
One obvious approach is to unfold stiff wings with the keys on them. We understand how to make these, and they'd be not much less robust than the current designs. For the cost of slightly little more complex connections and a thicker package you get room for bigger keys, clearer labels, and a bigger screen.
The downside is that the wings have to be supported somehow. Think of trying to press buttons on a surface that wobbles from side to side. The user has to hold the phone with his hand open much wider--but that means the grip on the phone center is less secure. Try it on your own hand and see what I mean.
The wobble effect doesn't have to be a showstopper--with a little clever case molding you can probably make the phone fairly stable in your hand. And if you separate the dialing keys from the function keys you will probably make it easier to remember how everything works.
Another possibility for really miniaturized devices, requires that the number of virtual buttons be small. You access them by sliding a central button up and down and side-to-side. Small detents give you tactile feedback when the slider reaches a new digit, and the screen could show which virtual button you are about to push.
Using moving parts is less robust than ordinary buttons, of course, but you have a very simple layout: the slider/dialer and a few additional buttons beside it for other functions. I suspect that using it would be much quicker than punching buttons.
Navigation will be confusing if you have more than 3x4 or 4x3 virtual buttons, and the mechanics will be more complex and delicate. And the phone will be less water resistant. But it could be pretty doggone small.
