The latest patent, first reported on Windows Central, was filed in 2016 by Microsoft and describes "input based on interaction with a physical hinge", which outlines complexities introduced to touch input on a dual-screen hinged device compared with a single-screen device.
"Consequently, a typical gesture language may be inefficient for these devices given the ergonomics of holding and interacting with such a device. This can detract from user enjoyment and lead to user frustration when using these types of devices," Microsoft's engineers write.
Microsoft says the hinge design necessitates a new class of "hinge-based interactions" that involve the user moving the hinge to provide the computer with an input.
The hinge gesture could be used to start system-level commands, operations, interactions with content, and initiate transitions between views. Microsoft suggests a hinge angle change could be used to switch between a single-tasking state and multitasking state.
The company also considers the possibility of combining other input signals with hinge gestures, for example, for multitasking actions, to launch a related app, or to create a different view in the same app.
These signals could include the speed a hinge is moved at, how the user is gripping the device, and the screen's orientation.
If hinge gestures ever become a thing, Microsoft's engineers think it would be good to provide user feedback to show how far the user has to go to complete a gesture, such as a progress bar indicating what percent of a given action has been completed.
They also think audio and haptic feedback would be useful to tell the user if a gesture is being performed correctly or incorrectly.