Using the words “convoluted” or “confusing” to describe the patent battles going on in the mobile space might be going a little easy on them. Everywhere it seems companies are suing one another over anything they can think of, while others collect license fees from device and software makers just looking to avoid ending up in court. Just about everyone owns a small number of the patents necessary to create a smartphone or a tablet, and they’re all constantly at war over them.

But a new patent just awarded to Apple brings a whole new level of pain to the game. According to a story from ZDnet, the U.S. Patent and Trademark Office just issued Apple a patent for a design feature that’s found on every iPhone, iPod Touch and iPad, as well as just about every single Android device currently in existence: “slide to unlock.”

This is the feature on touchscreen devices that requires users to “unlock” the device by sliding a thumb over a specific section of the screen, where it looks like they’re moving a button from one position to another. The slide feature has been widely adopted because it’s both simple and genius – it’s hard to accidentally unlock your phone in your pocket and start making inadvertent calls with the “slide to unlock” feature in place.

This is a pretty big new gun in the Apple patent fight arsenal, specifically because it is so widespread, and because it’s a user experience element rather than a physical element. In Apple’s battles with Samsung, for example, Apple is claiming infringement in a much more generalized way – it maintains that the “look and feel” of the iPad and iPhone have been copied in Samsung’s devices. And that argument seems to be working, with Samsung’s devices being temporarily banned in Germany, the Netherlands and Australia.

It might be possible to argue that the entire Android experience copies the “look and feel” of Apple’s iOS platform if Apple can demonstrate with tangible elements like “slide to unlock” that Android is borrowing its ideas. Of course, that discounts the fact that Apple has borrowed ideas from Android – the new notifications system in iOS 5 is definitely cribbed from Google’s mobile operating system – but what matters is what a judge thinks. Apple currently has the ability to take on any mobile device maker it wants that uses Android. It might not win, but that doesn’t change the capability.

However, “slide to unlock” is so minor a feature that it’s possible it’ll never come to blows in the courts. In fact, I’d be surprised if Google wasn’t spending the day figuring out a new way to unlock its devices that could be quickly disseminated in a small patch to carriers and device makers. Apple might have a patent on “slide to unlock,” but Google could likely come up with something just as effective to replace it. And that would have the benefit of presenting another distinctly Android effect to Android users – the kind of experience that mobile device users want and appreciate.

So while Apple might appear to have Google up against the ropes on this, I somehow doubt it’s going to have much of a rippling effect. If Google decides not to change the feature, it and its partners could still fight the patent in court, and they might just win. It’s hard to predict how cases like these will shake out, and the ubiquity of touchscreen devices and the simplicity of the “slide to unlock” design probably would work in Android’s favor.