HTC isn't the only company with designs on a 3D phone. The likes of Apple and Sharp are also rumoured to be looking at 3D and now, it looks like RIM could be joining them.BlackBerry manufacturer Research In Motion (RIM) is rumoured to be planning for BlackBerries featuring a three-dimensional display, according to TechRadar. It's backed up by the company's recent purchase of Swedish company The Astonishing Tribe (TAT), who are specialists in producing 3D user interfaces.Apparently, TAT has been working on 3D displays for a while now, developing technology that would be well-suited to use in a smartphone. With RIM owning TAT, there's every chance that the technology could be heading to the phone in the future, possibly as soon as next year.But it's not quite so cut and dried as that. While you can see the likes of Apple and HTC using 3D to drive sales of 3D games, movies and other apps, that's not really the current BlackBerry market. If the company went down that road, it could alienate its core audience, with no guarantee of building a new one.Only time will tell. But don't expect to see anything until late 2011 at the very earliest.