When you think about it, there's no reason that biometric recognition can't provide security on tablets -- well, aside from the need for a sensor thin enough to fit on a slate. Fujitsu has been on the job, making significant progress since showing off its clunky palm vein reader. The company's latest development on the biometric front is an authentication sensor that measures a minuscule 5mm thick, which is slight enough for use in tablets. Fujitsu employed its PalmSecure technology for reading users' palm vein patterns without requiring physical contact with the sensor. This super-thin module is still in the thick of research and development, but it's likely destined for your tablet someday down the line.