As i feel this a simple thory that was mplemeted time ago and now it has come to a better level. When i serched on web for the technology it expalined here.

This is how you see the screen if you look at the screen without glasses.

This Keypad has 17 keys in a area of size 9.5X6.5. So If we calculate the area of a unit key, that will be 3.63 (cubic centimeters per key). But the good thing is this keypad is extremely easy to use. I can type super fast even without looking at the keys.
Then a general calculator. Normal size of a general calculator will be either same as that of a Keypad or less. We'll amuse that it is of size 8X5. So the area of a unit key will be 1.53.
And this is the most probable answer for my question. It's super cool. I know there are plenty of keys inside this tiny area. BUT who are you going to press those?. The area is around 2X2 cm in size. And have 16 keys on it. I don't see any use of all the keys if you don't have a pin. So the unit area for a key is 0.25.
The Other keypad that everybody users now a days is the mobile keypad. This is taken from the N95. it has 12 keys in a area of 4.5x2.5. So the area of a one key can be calculated as 0.93. This key pad is far better sample of a compact design.
And if you count the number of keys there that is 13. And the area taken by a single key is 0.46.We are creating an uncompromising middleware platform for Web services which treats Web services as first class components instead of as a facade to some existing platform like J2EE. Apache Axis2 is the first SOAP stack which espouses this design in its guts: we focus entirely on doing what's right for Web services first. We make no apologies for being XML centric instead of Java object centric. An add-on layer allows Axis2 to play by the, sometimes klunky, Java rules and regulations (like JAX-RPC) for those who want the comfort of (and are willing to pay the price of) those rules & regulations.
The best part is, all of our software is available free under an open source license.
The even better part is, we are not just giving the software away under open source licenses, but we are also developing it in true open source fashion fully involving the user community. Our role in Apache Web services projects proves that but much more is to come. We've only just begun.
In WSO2, in addition to building the pieces in Apache, we are working on offering integrated Web services server stacks which will provide uncompromising solutions to those looking for the absolute best Web services middleware. "
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