Microsoft has long been rumored to be developing a foldable smartphone. Though the Redmond-based tech giant has yet to officially confirm such a device, a new patent provides hints on what the upcoming smartphone — dubbed the Andromeda or Surface Phone — may look like.

The patent, titled "Hinge With Free-Stop Function," was published by the World Intellectual Property Organization on Thursday, Dec. 21. The patent application describes a hinge mechanism designed for a dual-screen device. The placement of the hinge allows both displays to be rotated up to 360 degrees with respect to each other.

The hinge is seamlessly integrated into the device so it does not stick out or protrude. The foldable smartphone will lay flat when opened. The hinge's free-stop function will also allow the device to remain propped up without the user having to hold it.

Apart from detailing the mechanisms and illustrating the embodiments of the hinge, Microsoft also explained the value of releasing a dual-display smartphone.

According to the tech giant, consumers are interested in devices that increase the size of the display without affecting its form factor. They want to enjoy a device with an expansive display but at the same time have it still fit comfortably in their hands or their pockets.

Thus, dual-display devices are becoming more popular. However, at this time, hinges on such devices remain "problematic." Microsoft's patented hinge mechanism aims to rectify this issue.

Other rumored specs for the Andromeda/Surface Phone include 6-inch organic light-emitting diode (OLED) displays and a modified USB-C port.

Another patent also details the multitasking potential of the upcoming foldable smartphone. The device is expected to have pen support for notetaking or sketching. The displays can also be transformed into different modes such as a full-screen tablet or a mini laptop with the second display turned into a virtual keyboard and trackpad.

Microsoft's foldable smartphone is rumored to be released sometime in 2018.