Apple has been granted a patent for a retro-style flip phone with an OLED screen display. 

The patent, published yesterday, details a foldable potential future iPhone with a flexible OLED display that spans from edge to edge.

Similar to flip phones popularised in the 90s by brands like Motorola, the phone is capable of being folded in half across its middle.

According to the patent, the phone would be split into two halves and joined by a hinge mechanism. The OLED screen itself doesn't split, and instead bends around the hinged case.

Connections between the two case sections would be made through flexible printed circuit boards.

Apple is yet to make wide use of OLEDs, which emit light across a surface rather than from a specific point. However, it has introduced the technology through the Apple Watch, and sources – including blog Apple Insider – speculate that it is likely to feature in 2017's iPhone.

In one example, the proposed flexible screen folds over onto itself. But an opposite configuration describes the display as facing outward after folding, with clips for fastening onto a user's clothing.

The document also details options with two hinges and a glass covering, and with different viewing angles taken into consideration.

Apple famously files large numbers of patents each year, although most never come to fruition. Earlier this year, the company sent an application for a customisable keyless keyboard, and were last year granted a patent for a wireless headset that mounts an iPhone in front of the eyes.