Another front has opened in the multi-faceted story of patent battles: Neonode, an optical touchscreen tech company based in Sweden, says that it has been granted a patent in the U.S. that covers the touch-and-glide gesture that it claims is used on devices like the iPhone and iPad.

The patent is notable not only because Neonode says the patent covers functions like the horizontal touch gesture that Apple uses between screens on its iOS devices, as well as in the slide-to-unlock feature. But also because slide-to-unlock is the same feature that Apple has been citing in its own patent lawsuits against Android device makers Motorola and Samsung.

That also underscores how even a piece of IP that one company has been claiming as its own can have a slippery position.

Neonode’s head of IP, Yossi Shain, says the company first filed the application in 2002 and has similar patents pending in other countries.

Neonode says the patent, number 8,095,879 from the U.S. Patent and Trademark Office, complements other existing patents, numbers 7,880,732 and 8,068,101, which it says cover small and midsized touchscreen devices.

Neonode has a number of OEMs and ODMs who already license other touchscreen technology. Shain tells us that Sony and Barnes & Noble are two licensees — both use them in their e-readers — but declined to name others except to describe them at tier-one.

Shain says that the patent was officially granted on January 10, 2012, and so it is now beginning to look at “friendly licensing” deals, with Apple its first port of call, before embarking on anything more aggressive, like lawsuits.

We have contacted Apple for its response to this and will update the story as we learn more.