The U.S. Patent and Trademark Office has awarded Apple the popular slide-to-unlock feature, boasted by many smartphones nowadays, on a touchscreen device.

Apple had already been granted a similar patent before. Another major patent win would obviously strengthen Apple's position. The patent (U.S. Patent No. 8,406,721) is entitled Unlocking a Device by Performing Gestures on an Unlock Image, and has an open language as follows:

A device with a touch-sensitive display may be unlocked via gestures performed on the touch-sensitive display. The device is unlocked if contact with the display corresponds to a predefined gesture for unlocking the device. The device displays one or more unlock images with respect to which the predefined gesture is to be performed in order to unlock the device.

The performance of the predefined gesture with respect to the unlock image may include moving the unlock image to a predefined location and/or moving the unlock image along a predefined path. The device may also display visual cues of the predefined gesture on the touch screen to remind a user of the gesture.

In addition, there is a need for sensory feedback to the user regarding progress towards satisfaction of a user input condition that is required for the transition to occur.
 
In fact, in 2005, long before the first iPhone was unveiled, Apple had already applied for the unlock gesture.

Moreover, in 2007, Apple co-founder Steve Jobs described this feature in a presentation: To unlock the phone, I just take my finger and slide it across. Wanna see that again? We wanted something you could not do by accident in your pocket. Just slide it across - BOOM!

According to the patent, any mobile devices that use the slide-to-unlock function may infringe Apple's patent right.  However, many companies have copied this feature in their smartphones, such as Samsung, and HTC.

Actually, Google's Android operating system uses this feature and so does Microsoft's Window 8. Apple has been in severe patent legal battles with different companies across the world including Samsung and HTC and this win can help Apple take the lead.

It is pretty clear that any device using this feature could be sued for patent infringement. And, the number of devices offering it will encounter a dramatic decrease, as the competitors of Apple would have to think twice before they use it.