Smartphone manufacturers have already been treading on eggshells to avoid infringing on Apple’s lock screen patents. Now that Apple has been granted the right to ban Motorola from copying its slide to unlock feature, lock screen patents are an even bigger thorn in manufacturers’ side.

However, Patently Apple is showing off a number of lock screens apparently patented by Google that manage to steer clear of Apple’s patents, while providing screen lock options that remain simple and fully-functional.

With a multitude of unlock methods to develop, it looks like Google has a choice as to what will wind up on its range of Android devices.

A likely option is the circular lock screen, rocking a design that’s not too dissimilar to what can be found on Ice Cream Sandwich – complete with multiple shortcuts with drag-to-open functionality.

Interestingly, the mention of voice input suggests Google may be working on a voice controlled screen unlock mechanism.

As you can see, another of Google’s potential unlock systems is based around a bar at the top of the screen, containing icons that can be dragged down to in order to unlock them.

If these are indeed Google patents, there’s every possibility one of them might turn up on the lock screen of Android 5.0 Jelly Bean as Google continues its battle to win iPhone users over to Android.