So there will not be any more trackballs for future Blackberries and Android phones?
So How Does that Optical Mouse on a BlackBerry Work, Anyway?: "
The timing on this look under the hood of an optical mouse is pretty good. Earlier today, Sprint announced availability of the BlackBerry Curve 8530 for a low $49.99 and it sports one of those optical trackpads. I got my first look at one with the Curve 8520 and before I even touched the device, I wondered how well the itty-bitty trackpad would work. Turns out it works quite well, but I still wanted to know how. Lucky me — the official Inside BlackBerry blog reveals how this magical mouse works today.
Turns out there’s an LED sensor under the small trackpad, just like the kind you’d see under an optical mouse. Only this sensor reads up instead of down and you move your finger instead of moving a device. Light from the LED reflects back from your moving digit and hits a sensor where the movement is converted into X- and Y-axis changes. (And here you thought you’d never use that simple third-grade geometry again!)