In a move that has long been rumoured, Microsoft has announced today on the Surface Blog that they have acquired the digital pen technology from N-Trig Ltd. This is the pen technology that they have employed in the Surface Pro 3, and now the Surface 3.
With Windows 10, pen input is getting even more useful, so this move makes a lot of sense.
One of the nice parts about the N-Trig technology is that the entire product stack required is much thinner, and there is no need for a deep level digitizer under the display, so the pen feels more like it is writing directly on the display.