MojoKid writes: Microsoft may have discontinued its Lumia family of smartphones, but that doesn't mean that the company has given up on handsets altogether. A new patent filing reveals that Microsoft could still have a few more tricks up its sleeve; in this case, a folding smartphone. If such a design were to make it to production, it would likely adopt Surface branding, joining the likes of the flexible and convertible Surface Pro, Surface Book and Surface Studio. Entitled "Mobile Computing Device Having A Flexible Hinge Structure", the patent shows a smartphone with a side-mounted hinge that opens up to reveal an uninterrupted, large display surface more fitting for tablet duty. And just like patent filings leaked the Surface Studio months before its official unveil, this could be a precursor to a future Microsoft product. Of course, there are no guarantees when it comes to patent filings, as Microsoft has patented many design innovations without acting on them with a shipping product.