Apple has received US patent #8,082,523 for a mobile phone with a touch screen and GUI which allows the user to invoke other apps while a phone call continues. Here's the abstract:
A portable electronic device displays, on a touch screen display, a user interface for a phone application during a phone call. In response to detecting activation of a menu icon or menu button, the UI for the phone application is replaced with a menu of application icons, while maintaining the phone call. In response to detecting a finger gesture on a non-telephone service application icon, displaying a user interface for the non-telephone service application while continuing to maintain the phone call, the UI for the non-telephone service application including a switch application icon that is not displayed in the UI when there is no ongoing phone call. In response to detecting a finger gesture on the switch application icon, replacing display of the UI for the non-telephone service application with a respective UI for the phone application while continuing to maintain the phone call.
At first this would seem to be a big problem for other players in the smart phone market, as they all now allow users to run other apps while a phone call is in progress. Experts believe there might be prior art, depending on how precisely the patent is to be construed.
There are many examples of earlier smartphones, including BlackBerry and Palm Treo phones, that allowed this function. But these were not touch screen phones. In the abstract above and in the more detailed list of Claims, the patent speaks largely of user interface and finger gestures. The patent only claims certain methods of invoking an application while a phone call is in progress. Apple filed the patent application on Jan. 6, 2008.
Other smart phones would seem to violate the Apple patent, narrow as it might be. But Apple has many user interface patents related to various gestures.
The Apple patent in flowchart form.
So it's not clear whether a prior art argument would work. "The other big question is whether this patent is obvious. When something is 'obvious,' it is not patentable, but it is difficult to make a clear-cut definition of obvious," Deborah Sweeney, CEO of MyCorporation.com, told BYTE in an email interview.
How did we get to a situation where such things are patentable? The US Patent and Trademark Office (USPTO) has been issuing a flood of such patents for years, making it difficult for software developers to know what is and isn't off limits. Says Sweeney, "...this patent may be considered by many to be weak and calls into question whether the USPTO is monetarily motivated to issue patents."